Objective Extracorporeal membrane oxygenation (ECMO) is used to provide continuous extracorporeal blood oxygenation to patients with severe cardiopulmonary failure to maintain the patients' life. The ECMO device consists of an oxygenator, a centrifugal pump, and a control system, of which the oxygenator is the core component for accomplishing the blood oxygenation. This study addresses the problem of technological gaps in the preparation of separation membrane fabrics for oxygenators and presents a study on the low-damage preparation of ECMO membrane fabrics based on warp knitting technology.

Method Through the stitch analysis of membrane fabrics made from polymethylpentene (PMP) hollow fibers membrane, the parameters such as knitting stitch, yarn type and other fabric specifications of membrane fabrics were determined. The knit fabrics were manufactured on the special Tricot warp knitting machine from PMP hollow fiber membrane. Based on the experimental results and the understanding of the knitting equipment, warp yarn tension was identified as one of the main influencing factors affecting the damage of the PMP hollow fiber knitting. An adaptive warp yarn tension control method was proposed with the Tricot warp knitting machine through the PID control strategy design and the fifth degree polynomial curve planning, aiming to achieve low-damage knitting of PMP hollow fiber.

Results The results showed that the damage of prepared ECMO membrane fabrics was mainly caused by the mismatch of yarn demand between the warp feed and knitting action at constant speed. The knitting tension amplitudes at 900, 1 000, and 1 100 mm/rack warp feed were 28, 23, and 19 cN, respectively, which led to the attenuation of PMP hollow fiber strength, outer diameter, and air flux. The ECMO membrane fabrics were prepared using the adaptive tension control method. The warp tension amplitude in a single cycle was regulated from 2.4-23 cN to 3-10 cN at the warp feed of 1 000 mm/rack, and the tension fluctuation amplitude was reduced by 56.5%. The results of ECMO film fabric preparation under adaptive tension control showed 3% loss of outer diameter and a 5% loss of strength at the weaving position. The N₂ flux was decayed by 17%, CO₂ flux by 12% and O₂flux by 14% before and after braiding. Compared with the experiment without adaptive tension control, each gas flux index showed 65% enhancement of N₂ flux, 63% enhancement of CO₂ flux, and 62% enhancement of O₂ flux, which further exemplified the effectiveness of the adaptive tension control scheme for the low-damage preparation of ECMO membrane fabrics.

Conclusion In this paper, based on warp knitting technology, a self-adaptive warp tension regulation method was developed to realize the low damage preparation of ECMO warp-knitted membrane fabrics by using homemade PMP hollow fibers as the substrate. The main research conclusions are as follows. 1) Through the membrane fabric preparation experiments, an adaptive tension control method is proposed, and through the PID control strategy and the fifth polynomial speed planning curve, the "peak shaving and valley filling" of the warp yarn tension curve in the preparation process of ECMO membrane fabrics is accomplished, realizing the low-damage preparation of ECMO membrane fabrics. 2) The strength, outer diameter, and air flux of the PMP hollow fiber are significantly attenuated during the knitting process of the ECMO membrane fabric on a HKS Tricot warp knitting machine. This attenuation is primarily attributable to the material properties of the PMP membrane. A key contributing factor is the mismatch between the constant speed let-off rate and the actual amount of yarn required for the knitting process. 3) By testing ECMO membrane fabrics preparation under adaptive tension control, it was found that the mechanical properties, outer diameter, and air permeability of the PMP hollow fibers were significantly improved. The N₂ flux of the prepared ECMO membrane fabrics was attenuated by 17%, the CO₂ flux was attenuated by 12%, and the O₂ flux was attenuated by 14%. The flatness, density, and gas flux results of the fabric have reached the level of foreign products.

Objective Flexible actuation materials with environmental stimulus responsiveness can respond to external stimuli and have corresponding actuation behaviors such as bending, deformation, rotation and contraction, which has great application prospects in the rehabilitation medicine, intelligent switches, artificial muscles, flexible robots and so on. However, the current problems, such as poor responsiveness, complex preparation process, high cost, and large pollution of stimulus sources, have greatly limited the development of the flexible actuation materials.

Method The polyvinyl alcohol(PVA)-ethylene(PE)/cellulose acetate butyrate (CAB) fibers were prepared by blending PVA-co-PE with CAB and then melting and extrusion. The PVA-co-PE nanofibers were obtained by separating CAB from composite fibers using acetone as solvent. Then, the obtained PVA-co-PE nanofibers were cut into pieces and put into a high-speed shear machine containing isopropyl alcohol aqueous solution (the PVA-co-PE nanofiber concentration was controlled at 3%), and a uniformly dispersed PVA-co-PE nanofiber suspension was formed by high-speed shearing for 2-3 min. Then, the obtained PVA-co-PE nanofiber suspension was evenly sprayed on the surface of PET substrate. After the solvent evaporated, the PET substrate was removed to obtain an independent PVA-co-PE nanofiber membrane. Then, the SiO₂ nanoparticles were dispersed in an aqueous solution with a concentration of 5%. Then, the dispersed SiO₂ nanoparticle dispersion solution was sprayed on the prepared PVA-co-PE nanofiber membrane. After drying at room temperature, the PVA-co-PE/SiO₂ composite actuation membrane was prepared. The microstructure characterization, contact angle properties, mechanical properties and actuation deform ability of the PVA-co-PE/SiO₂ composite actuation membrane were characterized.

Results First, the angle θ between the bending deformation of the PVA-co-PE/SiO₂ composite actuation membrane and the horizontal plane under the stimulation of moisture was taken as the maximum bending angle. It can be seen that the nanofibers stack layer by layer to form a disordered network structure, and with the decrease of the fiber diameter, the network structure of the nanofibers gradually decreased and became more uniform. In addition, the smaller the diameter of the PVA-co-PE nanofibers, the larger the specific surface area that can be provided, and the more conducive to the adhesion of SiO₂ powder on the surface of the PVA-co-PE nanofiber membrane. In addition, when the fiber diameter increased from 180 nm to 390 nm, the water contact angle on one side of the nanofiber membrane increased from 46.69° to 55.7°, and the water contact angle on the side of SiO₂layer increased from 10.9° to 45.9°. In other words, with the increase of nanofiber diameter, the hydrophilicity of both sides of the composite actuation membrane showed a decreasing trend. At the same time, the fiber diameter also had a great impact on the tensile properties of the composite membrane. As the diameter of the PVA-co-PE nanofiber increased from 180 nm to 390 nm, the tensile fracture stress of the PVA-co-PE/SiO₂ composite actuation membrane increased from 5.27 MPa to 6.94 MPa and the tensile strain increased from 3.33% to 8.99%. Then, the maximum bending angle and response speed of the composite membrane were characterized. The results showed that as the fiber diameter decreased from 390 nm to 180 nm, the maximum bending angle of the PVA-co-PE/SiO₂ composite membrane increased from 52.25° to 180°. At the same time, the increase of fiber diameter also affected the response speed of the composite membrane. With the decrease of fiber diameter, the response time of the composite actuation membrane decreased from 1.2 s to 0.7 s, and the bending angle of 180° was reached within 0.7 s. Additionally, the maximum bending angle of the PVA-co-PE/SiO₂ composite actuation membrane decreased with the increase of particle size of SiO₂ powder. As the particle size increased from 15 nm to 200 nm, the maximum bending angle decreased from 180° to 34°, and the response speed also gradually reduced from the initial 0.7 s to 1.2 s. Based on the excellent moisture stimulation response, the PVA-co-PE/SiO₂ composite actuation membrane was prepared into a bionic finger structure, which can induce the bending and stretching behavior similar to the human palm under external moisture stimulation.

Conclusion A PVA-co-PE/SiO₂ composite actuation membrane with an asymmetric structure was prepared by a simple spraying process. The tensile performance of the composite actuation membrane was greatly improved with the increase of fiber diameter, which can be attributed to the fact that the larger the fiber diameter, the larger the pores in the three-dimensional network structure of the nanofiber membrane, and the larger the relative slip space between the fibers, leading to increase in elongation at break. In addition, the hydrophilicity of the composite membrane also increased with the decrease of fiber diameter and powder particle size of SiO₂. This is because the smaller nanofiber diameter resulted in the dispersion effect of the powder, which in turn promoted rapid penetration and diffusion of water molecules on the membrane surface, and improvised the hydrophilicity. Finally, the PVA-co-PE/SiO₂ composite actuation membrane showed excellent actuation performance under external moisture stimulation. That is, the maximum bending angle of 180° can be reached within 0.7 s. This can be interpreted as the different hygroscopic response between the upper and lower layers, the PVA-co-PE/SiO₂ composite actuation membrane would have asymmetric hygroscopic swelling when stimulated by moisture, which led to the rapid and reversible deform behavior. Based on the rapid stimulation response and large-scale deformability of the composite actuation membrane, it has a great application prospect in the fields of intelligent control, artificial muscle and intelligent clothing.

Objective At present, self-coiling technology is rarely used in the field of blood vessels. Thermally induced self-coiling can make vascular tissue engineering materials self-coil at the corresponding temperature to wrap the injured blood vessels, which has a better fit compared with the existing artificial blood vessels. At the same time, self-coiling is irreversible, and the hardness of tissue engineering materials is enhanced after self-coiling. In orderto solve the problem of vascular endothelialization, gradient modification of growth factors was applied to the surface of the thermally induced self-coiling scaffolds to promote rapid endothelialization of the inner layer of the scaffold. At the same time, the scaffold has a multi-layer microstructure, which simulates the fiber direction of each layer of the blood vessel and has bionic performance.

Method Poly (l-lactic acid) (PLLA) and poly(lactic-co-glycolic acid) (PLGA) were used as raw materials to fabricate thermally induced self-coiling PLLA/PLGA nanofibrous vascular scaffolds by electrospinning technology. The thickness of the scaffolds was measured by a micrometer. The scaffold can self-coil at 37 ℃, and the driving force of self-coil comes from the difference in molecular motion rate between PLLA and PLGA after heating. The surface morphology of PLLA and PLGA nanofibrous membranes was observed by SEM. The gradient growth factor modification of the inner layer of the scaffold was made by electrostatic spraying technology and different mold coverings, and the gradient preparation was observed under fluorescence microscope by replacing vasular endothelial growth factor (VEGF) with rhodamine. The cytocompatibility of scaffolds was tested by CCK-8 assay. The effect of gradient-modified growth factors on rapid endothelialization was examined by seeding cells on both sides of the scaffold and observing them by fluorescent staining after 3 d.

Results The prepared PLLA/PLGA vascular scaffold had a multi-layer oriented nanofiber structure. The microstructures of the inner PLGA and the outer PLLA nanofiber membrane were both oriented fiber structures. The thickness of the scaffold was (6.75 ± 0.4) μm, and it could be self-coiled from a flat structure to a tubular structure at 37 ℃. The CCK-8 experiment showed no significant difference in cell proliferation in each component. The characterization results of gradient modification using rhodamine instead of VEGF showed that the fluorescence intensity gradually increased from both sides to the middle part with the increase of electrostatic spraying time, indicating that more growth factors were modified in the middle part of the inner layer of the scaffold. Gradient of growth factor accelerates the crawling of endothelial cells, and after 3 d into the luminal surface gradient growth factor of cell migration distance are 3.5 times that that of the control group.

Conclusion The preparation of PLLA/PLGA scaffolds has a multilayer orientation nanofiber structure and good biocompatibility. At 37 ℃, the scaffolds can be coiled into a tubular structure. VEGF was in a successful gradient modification on the inner lining to speed up the migration of endothelial cells and promote the fast endothelium of blood vessel lining. However, there are still some problems such as weak adhesion to the vascular stent and gaps after crisping. The adhesion of the scaffold needs to be improved in the future.

Objective For protective materials, excellent protective performance and wearing comfort are both important for their application. Although the nanofiber membrane has excellent protective performance, the small pore size and narrow pore size distribution prone to produce a stuffy feeling when worn for a long time, and would affect air permeability and moisture permeability. The wearing comfort of nanofiber protective materials still needs to be improved. Many ways are proposed to improve the wearing comfort of protective materials. Among them, the infrared radiation transmittance of the material has an important impact on its temperature regulation function, thus affecting the wearing comfort.

Method In order to improve the wearing comfort of nanofiber protective materials, the radiation cooling polyolefin elastomer (POE) nanofiber membrane was prepared by using the melt blended phase separation and subsequent deposition process. The morphology, infrared radiation transmittance, transparency, radiation cooling effect and water vapor transmittance of POE nanofiber membrane were studied and compared with the poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofiber membrane and cotton fabric.

Results The morphology of POE nanofiber membrane is uniform, with an average diameter of 570 nm, which is larger than that of PVA-co-PE nanofiber membrane. The POE nanofiber membrane is completely transparent to light in the mid-infrared band (7-14 μm), with a transmittance of almost 100%. This is mainly because the molecular structure of POE has no groups that can absorb mid-infrared light, and its pore size is much smaller than the mid-infrared wavelength, so it does not affect the mid-infrared radiation transmittance. The infrared radiation transmittance is directly related to the thickness of nanofiber membrane, and it decreases significantly with the increases of POE nanofiber membrane thickness. In contrast, the structure of PVA-co-PE contains groups that can absorb mid-infrared light, so that its transmittance in the corresponding band is reduced, while cotton fabric cannot transmit infrared light at all. As the infrared radiation accounts for more than 50% of the total heat loss of the human body, the POE nanofiber membrane has better infrared radiation cooling effect. At room temperature, the temperature of the heating module rises by only 0.5 ℃ after POE nanofiber membrane covering. Under vacuum, the temperature of the heating module remains unchanged after the POE nanofiber membrane is covered. Notably, the infrared transmittance of a material is not related to its transparency. In the visible light band, the transmittance of POE nanofiber membrane and cotton cloth is close to zero, and the transmittance of PVA-co-PE nanofiber membrane is about 30%. This is because the pore size of the POE nanofiber membrane is comparable to the wavelength of visible light, and light scattering makes the POE nanofiber membrane unable to transmit visible light. In addition, although POE is a hydrophobic polyolefin elastomer, it still has good moisture permeability by virtue of its three-dimensional porous structure. The water vapor transmittance of POE nanofiber membrane is 2 845 g/(m²·d), which is just slightly lower than the water vapor transmittance of 3 530 g/(m²·d) of cotton cloth. Therefore, the POE nanofibers can be used as coating materials to be coated on different substrate surfaces to improve the substrate protection performance without affecting its thermal and humid comfort.

Conclusion the prepared radiation cooling POE nanofiber membrane with excellent wearing comfort has a better thermal radiation cooling effect than PVA-co-PE nanofiber membrane and cotton fabric. The temperature change little after POE nanofiber membrane covering, hence maintaining excellent thermal comfort. In addition, the three-dimensional pore structure of POE nanofiber membrane gives it excellent moisture permeability, and its water vapor transmittance is only slightly lower than that of cotton fabric. The results demonstrate that the POE nanofiber membrane has excellent thermal and humid comfort, and it can be used as protective layer for medical use to improve protection without affecting comfort.

Objective In filtration simulation calculation for internal structure of fiber assemblies, the fiber filtration medium model established is limited to a single cylinder. Although this simplified model is conducive to the rapid solution of the problem, its limitation is that it cannot fully demonstrate the influence of multi-fiber structure on the filtration performance. In practical engineering applications, fibers in the assembly used for air filtration have axially curved structures, and are not completely cylindrical. If this factor is ignored, the simulated results will be inevitably different from the actual test results, and the filtration characteristics and internal pressure loss of the filter material can not be accurately described. In order to simulate and predict the properties of fiber filter media more accurately, more complex models need to be built to describe the internal structure of fiber assembly. This includes considering the bending and random arrangement of the fibers. The refined model will help understand furtherthe flow characteristics and filtration behavior of fiber filter media, improve the consistency of simulation results and actual test results, and provide a reliable scientific basis for the design and optimization of filter media in engineering applications.

Method A three-dimensional fiber filter media model with curvature K=0, 2, 4 and 6, solid volume fraction of 8%, randomly distributed in space was established by Digimat modeling software. Combined with computational fluid dynamics methods, based on Lagrange discrete model and Laminar flow field, similarity principle and Reynolds similarity criterion were used. The inlet velocities were set as 0.05, 0.142, 0.5, 1 and 2 m/s, respectively, and the average particle size was 0.25, 0.5, 1, 1.5, 2.5, 4 and 5 mm. The gas-solid two-phase flow inside the micron fiber model was numerically simulated.

Results As the fiber curvature K increases from 0 to 6, when the inlet velocity is 0.5 m/s, the distribution of the fiber in the filter region is irregular, random and asymmetrical, and the flow velocity distribution is also irregular, and the influence of curvature on the velocity field distribution is not obvious. With the increase of the curvature of the fiber model, the internal pressure loss of the fiber model increases linearly. The pressure value of the windward side of the fiber is greater than that of the leeward side, and the pressure loss when the curvature K is 6 is significantly greater than that when the curvature K is 0. The filtration efficiency of fiber filtration medium increases with the increase of model curvature. When the inlet velocity is 1 m/s and the curvature K is 6, the filtration efficiency of particles with an average particle size of 5 mm is close to 90 %, which is significantly higher than the filtration efficiency of K=0 under the same particle size. This is because the curvature of the fiber increases and more bending and folding will appear on the fiber surface, which will increase the surface area of the fiber. The larger surface area of the fiber provides more opportunity for the fiber to contact with the dusty air stream, which makes it easier for the fiber to collide with particles in the air stream and trap them. In addition, the greater the curvature of the fiber body, the greater the degree of deformation and distortion of the fiber body. Thus, a more complex and disorganized stacking and crossing structure can be formed between adjacent fibers, and the pore size between adjacent fibers is smaller, so that the interception and trapping capability of a single fiber on particles will be greatly improved, and the overall filtration efficiency of the filter medium will also be improved.

Conclusion The filtration efficiency and pressure loss of the fiber assembly increase with the increase of fiber curvature. In practical engineering applications, in order to improve the filtration capacity of the filter material, the filter material with more fold structure is used as far as possible to increase the filtration area and dust holding capacity of the filter material while ensuring the pressure loss as little as possible. The folded structure makes the fibers in the filter material show a high degree of non-uniformity. More interception sites and bending paths are created, effectively enhancing the interaction between particles and fibers, thereby improving the filtration efficiency of the filter material.

Objective A fiber dynamic pattern fabric design based on the grating animation principle is proposed to achieve the high-precision dynamic luminous picture pattern on the fabrics with color and brightness control.

Method This paper is based on the principle that grating gives static patterns dynamics. After dividing continuous movements into several specific patterns, a complete pattern is obtained after segmentation and rearrangement. The dynamic luminous fabric pattern was prepared on a jacquard loom by using polymer fiber with diameter of 0.25 mm and cotton yarn as raw materials. The polymer fiber is coupled to the light-emitting diode, and the light-emitting sequence and time of different action patterns are controlled by grouping electronic components grating to show dynamic moving patterns on the flat fabric.

Results Based on the analysis of the principle of raster animation, this paper expounds the realization principle of grating animation and the influence of different parameters on the animation display effect of optical fiber luminous fabric and the realization method for engineering of dynamic picture fabric using optical fiber for practical application. Drawing on the principle of grating animation, the light-emitting diode was adopted to control the optical fiber grouping, so that the animated pattern could be freely transformed on the optical fiber fabric. When the polymer fiber with a diameter of 0.25 mm was used as the smallest luminous unit, the fiber luminous fabric synthesized by 5 frames was found to be the best in the recognition and fluency of animation presentation. When the spacing stripe width was 0.25 mm, the object outline was clearer when the dynamic effect was presented. When the animation was composed of m images, the animation luminous frequency of 1/m s is the most appropriate. In other words, the optical fiber luminous fabric with an interval stripe width of 0.25 mm, a luminous frequency of 1/5 s and a pattern of 5 frames presented the best dynamic effect.

Conclusion Optical fiber luminescence is a dopted to display dynamic patterns, and the original grating image selection mechanism based on grating animation is evolved into an automatic image selection mechanism, facilitated by the use of optical fiber sequential luminescence without the need for a separate layer of grating. The single layer fabric prepared by using optical fiber and ordinary yarn has been proved to display dynamic patterns, which does not require the combination of grating fabric and base fabric as proposed in previous similar studies. By optimizing the fineness of the fiber, a graphic unit with higher precision is formed, and the visual effect of the luminous pattern can be further refined. By giving light to the packet fiber, not only can the white luminous dynamic pattern be obtained, it can also achieve color luminous dynamic pattern and color matching luminous dynamic pattern. The design of optical fiber luminous fabric pattern according to the pattern characteristics presents a new idea for aesthetic innovation of the clothing and textile industry, and also provides a new method for the information exchange in the field of safety warning.

Objective At present, light exercise is important for people's health. However, the conventional cooling and heating system has consumed significant amounts of energy to ensure optimal human body temperature during the light exercise. Sweat evaporation is an effective method for heat dissipation to maintain human thermal balance. The conventional textiles such as cotton fabric inevitably retain excessive sweat at the interface due to the intrinsic hydrophilicity, leading to wet and cool feeling. Therefore, fabrics with moisture and heat management capability is expected to transport liquid directionally, maintaining the skin dryness and finally achieving energy conservation and wearing comfort.

Method When a density difference exists on both sides of a single fabric, additional pressure difference will be generated to make water transfer spontaneously, according to the principle of differential capillary effect. Based on this principle, two polyester yarns (55.5 dtex(24 f) and 93.3 dtex(384 f)) were selected. Four concave-convex lattice fabrics were created with variations in structure, number, and distribution of connecting points, denoted as process A, B, C and D. In process A and B, the 55.5 dtex(24 f) polyester yarn was replaced by the 33.3 dtex(12 f) polyester yarn at the connecting coil to form obvious mesh, named as A2 and B4, respectively. In order to explore the influence of different coil structures on the moisture and heat management performance of fabric, 6 different fabrics A1, A2, B3, B4, C5 and D6 with the capability of moisture and heat management were prepared.

Results Fabrics in process A are configured with looping connecting coil and single tuck connecting coil, while process B incorporates three types of connecting coils: looping, single tuck, and double tuck coils. In contrast, process C only utilizes single tuck as the connecting coil, and process D incorporates looping connecting coil. Following the addition of 33.3 dtex(12 f) polyester yarn, fabrics A2 and B4 exhibited a noticeable mesh formation compared to A1 and B3. In order to assess the performance of the fabrics, various tests were conducted, including evaluation of moisture permeability, moisture management, droplet spreading, evaporation rate, and insulation rate. Analysis of the moisture permeability data revealed that fabric A1 outperformed the others. The presence of tuck connecting coils in processes B and C, spanning multiple horizontal rows, led to moisture condensation on the yarn/fiber and subsequent decrease in moisture permeability. Notably, the air permeability was primarily influenced by the fabric structure, with the introduction of 33.3 dtex(12 f) polyester yarn enhancing air permeability due to the formation of mesh. The weight of the fabrics demonstrated a positive correlation with unidirectional moisture transport capability. Thicker fabric D6 facilitated moisture transport, while the liquid easily penetrated soft fabrics. Fabric C5, featuring single tuck connection coil, displayed good unidirectional moisture transport and a large area change of droplet spreading due to the formation of transport channels. The relationship between evaporation and thermal insulation indicated a negative correlation, as faster liquid evaporation led to increased heat dissipation and decreased thermal insulation rate. The fabrics with a high proportion of microfibers, exhibited slow evaporation due to water absorption. Additionally, the mesh structure, provided improved evaporation efficiency. Overall, the connecting coils and fabric structure coordinately influenced the performance of fabric. As demonstrated by the correlation degree rankings, the comprehensive evaluation of the designed fabrics through grey relational analysis revealed that the tuck connection points in the process structure significantly influenced the fabric's heat and humidity management capabilities.

Conclusion Overall, the experiments show that the inner side of garment woven with 55.5 dtex(24 f) polyester yarn and the outer side knitted with 93.3 dtex(384 f) microfiber polyester achieved excellent unidirectional water transfer ab ability. It has been identified that the materials and structure jointly affected the comprehensive performance. The involvement of hydrophilic microfibre was found to reduce the moisture permeability and water evaporation rate. The connection coil of tuck was beneficial to unidirectional moisture transport but adverse to permeability. To the contrary, the structure of mesh was conducive to air permeability but poor in unidirectional water transport capability. In the final comprehensive evaluation, it demonstrated that single performance can not determine the overall moisture and heat management ability of the fabrics. The six fabrics used in this research are easy to produce without physical and chemical modification, which provides theoretical and experimental basis for the development of light sportswear fabrics with good moisture and heat management ability, environmental protection and durability.

Objective The aim of this study is to develop high-performance embroidered fabric electrodes for surface electromyography (sEMG) and optimize their process parameters. Four embroidered fabric electrodes with different stitch types were designed and produced to investigate the influence of stitch types on their conductivity properties and sEMG signal fitting performance, ultimately determining the optimal stitch type.

Method Fabric electrodes were produced using embroidery techniques by virture of the advantage of tailored fiber placement in embroidery. Silver-plated yarn, known for its high conductivity, served as the conductive embroidery thread, and elastic knitted structure were used as the substrate to improve the fit of the electrodes to the skin. Four embroidered fabric electrodes with different stitch types, i.e., tabby-stitch, box-stitch, annular-stitch and radial-stitch, were designed and produced. Skin-electrode impedance testing was conducted for each embroidered fabric electrode. In the states of walking and jogging, embroidered fabric electrodes and Ag/AgCl electrodes were aolopted to synchronously collect sEMG signal of the medial side of calf gastrocnemius muscle, and sEMG signal fitting performance of embroidered fabric electrodes and Ag/AgCl electrodes was evaluated in time-domain, frequency-domain and by correlation function analysis.

Results 1) Through skin-electrode impedance testing, it was found that direct embroidery on elastic knitted fabric tends to cause wrinkling in the fabric, resulting in deformation of the embroidered fabric electrodes. Placing non-adhesive interlinings such as paper interlining or cloth interlining on the bottom layer of elastic knitted fabrics cannot effectively solve this problem. However, using hydrosol double-sided fuse interlinings to synthesize elastic knitted fabrics and paper interlinings into fabric substrate for embroidery can effectively prevent fabric wrinkling and electrodes deformation. 2) Through skin-electrode impedance testing, it was found that stitch types significantly affect the skin-electrode impedance of embroidered fabric electrodes. During the test, the order of skin-electrode impedance was found to be annular-stitch electrode > box-stitch electrode > tabby-stitch electrode > radial-stitch electrode. The conductivity performance of embroidered fabric electrode with radial stitch is optimal. 3) In the time-domain comparison diagram, sEMG signal of each embroidered fabric electrode was basically consistent with that of Ag/AgCl electrodes. The time-domain indices extracted include root mean square (RMS) and average rectifying value (ARV), while frequency-domain indices encompassed mean power frequency (MPF) and median frequency (MF). RMS, ARV, MPF and MF of each embroidered fabric electrode were close to those of Ag/AgCl electrodes. Therefore, the sEMG acquisition effect of embroidered fabric electrodes were similar to that of Ag/AgCl electrodes. 4) The time-domain and frequency-domain characteristics of the sEMG signals collected by embroidered fabric electrode with radial stitch and Ag/AgCl electrodes were similar. Moreover, the ratio of information entropy of sEMG signal collected by embroidered fabric electrode with radial stitch and Ag/AgCl electrodes was the closest to 1, and the correlation coefficient between them was higher than 0.455 in the jogging state. So, it is believed that the sEMG signal fitting performance of the embroidered fabric electrode with radial stitch was better, and it was more suitable for sEMG monitoring. This result was related to the smaller skin-electrode impedance of embroidered fabric electrode with radial stitch, as generally speaking, the smaller the skin-electrode impedance of the electrode, the weaker the attenuation of the sEMG signal.

Conclusion The sEMG signal acquisition effect of four embroidered fabric electrodes with different stitch types are similar to that of Ag/AgCl electrodes, which verifies the feasibility of embroidered fabric electrodes. The type of stitch affects the skin-electrode impedance and sEMG signal fitting performance of embroidered fabric electrodes. The embroidered fabric electrode with radial stitch has the smallest skin-electrode impedance and demonstrated optimal sEMG signal fitting performance, indicating that optimizing stitch can improve the performance of embroidered fabric electrodes.

Objective Angle interlock composites have been widely used in defense engineering fields because of their excellent interlayer delamination performance, strong designability, near-clean forming and other characteristics, and can still maintain good structural integrity after post-processing. In recent years, major equipment components in the air, sky and sea have increasingly high requirements for lightweight, and, therefore, it is urgent to carry out innovative structural design and application of angle interlock composites to effectively reduce structural parameters and improve load-bearing efficiency. Among them, angle interlock composite with variable densities provides an effective means to realize the "light-strength coordination" of components.

Method In order to explore the influence of warp density or weft density on compression mechanical properties of angle interlock carbon/epoxy composites, the T700-12K carbon fiber was selected. Then three-dimensional (3-D) woven angle interlock composites with variable warp density or weft density and constant warp and weft density were prepared by resin transfer molding (RTM). On this basis, combined with digital image correlation technology (DIC), the out-of-plane compression test was carried out, and the damage morphology and damage distribution inside the samples were analyzed by scanning electron microscopy and computed tomography (Micro-CT). Finally, the progressive damage evolution process and failure mechanism of out-of-plane compression were sorted out.

Results All samples showed yield failure characteristics. In addition, by comparing with the compression specific strength and compression specific modulus of 5 types of composites, it was found that the compression specific modulus of samples with variable densities was significantly improved. Among them, the compressive specific strength of the warp yarn is dense at the top and sparse at the bottom composites (BJ-MS) sample was 4.36% higher than that of the warp yarn is sparse on the top and dense on the BJ-SM sample, and the compressive specific strength of the weft yarn is sparse on the top and dense on the BW-SM sample was 15.72% higher than that of he weft yarn is dense at the top and sparse at the BW-MS sample. In the warp and weft density remain unchanged composites (JZ) sample under compression load, the maximum strain first appeared at both ends of the sample. When the strain is 4.06%, a large range of stress concentration occurred in the middle region. Thus the continuously deformed resin matrix was first destroyed along the thickness direction, and then the load was transferred to the fiber bundle. Finally, there is an obvious kink phenomenon on the curved warp yarn. In the BJ sample under compression load, a large curved strain band appeared in the region with large warp density (strain 4.06%). With increase of the displacement, BJ sample finally developed a large range of delamination in the region with large warp density. For the BW sample under compression load, there is not only a large curved strain band, but also a kinking phenomenon in the area of small weft density (strain 4.06%). In addition, the damage of BW samples is slight in the area of larger weft density. According to the CT results, the interfacial cracks of the angle interlock composites were curved warp and straight weft. The damage volume and proportion of JZ samples were the largest, which were 26.90 mm³ and 3.09%, respectively. Moreover, as seen from the CT injury image the damage modes of the angle interlocking composites included matrix cracking, fiber debonding, fiber fracture and delamination.

Conclusion It can be concluded from the research that the variable density structural design is beneficial to improve the out-of-plane bearing capacity, and decrease the damage degree of the angle interlock composites. Because the bending degree of yarn varies with yarn density, the stress distribution along the thickness direction is affected. In addition, a variety of nondestructive testing methods can effectively reveal the damage process and mechanism of angle interlock composites. In the further study of three-dimensional woven angle interlock carbon/epoxy composites, it is necessary to develop a high-fidelity numerical simulation method. By establishing an accurate meso-structural model, researchers can effectively realize the prediction of progressive damage and failure mechanism.

Objective The confirmation of fabric quality in the textile industry is usually to put the woven fabric into the inspection equipment for inspection. When the fabric defects are found in the inspection process, the repair will be carried out and so increases the production time, thereby reducing the workshop efficiency. In order to improve the efficiency of the workshop, by collecting the real-time data of the weaving workshop, the fabric quality prediction model is established to predict the fabric quality and reduce the fabric production time.

Method Aiming at the problem of large difference in fabric quality and long time of conventional fabric inspection, a fabric quality grade prediction method based on K-nearest neighbor algorithm(KNN)improved PSO-BP algorithm was proposed by combining KNN and particle swarm optimization (PSO) improved error back propagation (BP) neural network algorithm. Firstly, the fabric quality prediction model is analyzed, and the fabric defects and fabric quality grades are divided. Secondly, 14 factors affecting the fabric quality are selected as the model input, and then the KNN algorithm is adopted to classify the original sample set. Finally, the classified data is brought into the fabric quality prediction model. The fabric quality prediction model is to use the particle swarm optimization algorithm to obtain the position and speed of the optimal solution through iterative update, and take this as the initial weight and threshold into the neural network structure for training to obtain the model. By predicting the fabric quality grade, the fabric quality is improved.

Results 16,186 fabric production data collected over a 3-month period from a textile factory in Lanxi, Zhejiang Province were adopted to establish a fabric quality prediction model. Firstly, the original data set was adopted to compare and analyze PSO-BP and BP algorithms with different training target errors. According to results of KNN-PSO-BP netural network model, PSO-BP algorithm showed higher accuracy and higher training speed than BP algorithm, and PSO-BP neural network model demonstrated an accuracy of 96% with the training target error 0.000 1. The KNN algorithm was adopted to divide the original sample set into five categories. The mean square error, accuracy and training time of the neural network model were calculated when the training target error is 0.000 1. The accuracy of the KNN-PSO-BP neural network model was 98.054%.

Conclusion This research demonstrated that KNN-PSO-BP algorithm has higher accuracy than PSO-BP algorithm and BP algorithm. The training time of fabric quality grade prediction is only 4.8 s, and the accuracy rate is 98.054%. The algorithm greatly shortens the detection time while ensuring the accuracy of fabric quality prediction, improves the production efficiency of weaving, and provides a certain basis for subsequent research on the location and size of fabric defects.

Objective Interfacial solar steam generation (ISSG) has emerged as a promising eco-friendly and low-carbon emission technology to address the global water scarcity. However, most current studies have focused too much on evaporation materials, ignoring the real bottlenecks are in the low-cost, scalable production and low fresh water yield in seawater desalination. In order to solve the above problems, this paper proposes a novel strategy to construct a water-electricity synergistic generator (WESG) by combining interfacial evaporation technology with photovoltaic generation.

Method The WESG containing a solar cell, thermoelectric generator, viscose fiber based nonwoven fabric and a copper condenser from top to bottom. The device skillfully uses the waste heat generated during the work of photovoltaic cells to facilitate interface evaporation, and solves the problem of low power generation efficiency caused by high temperature generated during the operation of the photovoltaic cells. The structure and wicking effect of the viscose fiber based nonwoven fabric, evaporation and electricity performance of the WESG was characterized.

Results The viscose nonwoven fabric is twisted, staggered, and interconnected to form a porous structure, resulting in good air permeability. The water droplets on the surface of viscose nonwovens fabric completely is diffused within 0.2 s, indicating that the water quickly reaches the gas-liquid interface and continuously supplies water to the evaporation interface. Assisted with evaporation process, the temperature of the photovoltaic cell is decreased from 62 ℃ to 48 ℃ under the simulated irradiation of 1 kW/m², and the evaporation rate reaches 1.36 kg/(m²·h). According to the voltammetry characteristic curve of the photovoltaic cell, the photovoltaic conversion efficiency is increased from 8.8% to 9.6% after cooling. The results show that the combination of photovoltaic power generation and interfacial water evaporation technology can effectively reduce the working temperature of photovoltaic cells and improve the photoelectric conversion efficiency of photovoltaic cells. The thermoelectric generator sheet can release 84 mV voltage, and the maximum power density is 28.12 μW/cm²during evaporation. The outdoor performance experiment of the WESG is able to generate 2.23 kg/m² of water and 37.3 (kW·h) /m²electricity in one day. The photoelectricity conversion efficiency and solar to vapor conversion efficiency are maintained at 9.5% and 82%, respectively during 144 h of cycle operation, suggesting that the excellent working stability of WESG. After purification, the ion concentration of salt water is decreased by 2-4 orders of magnitude, reaching the drinking water standards of the World Health Organization and the United States Environmental Protection Agency, implying that the WESG has a good water purification effect.

Conclusion In summary, this work provides a WESG with minimized energy loss and passive cooling condensation. The WESG cleverly uses the waste heat generated during the work of photovoltaic cells to realize interface evaporation, and solves the problem of low power generation efficiency caused by high temperature generated during the operation of the photovoltaic cells. The results show that the evaporation of water transported by viscose nonwoven fabric can effectively decrease the temperature of photovoltaic cells, and improve the photoelectric conversion efficiency of photovoltaic cells. This paper preliminary verifies the potential of utilizing traditional nonwoven materials and photovoltaic power generation to realize water-electricity synergistic generation and large-scale application.

Objective Flexible fabric pressure sensor arrays have great application potential in detecting and distinguishing the physical state of the elderly, because this technology offers high detection sensitivity, wide detection range and simple fabrication process. However, in the process of fabricating the piezoresistive flexible pressure sensor array, it is difficult to avoid the occurrence of abnormal sensing units and crosstalk, which results in the collection of inaccurate pressure data. In particular, the crosstalk phenomenon of the flexible pressure sensor array will cause serious distortion of the pressure contour generated based on the collected pressure data. The aim of this work is to devise a method for solving the problems mentioned above.

Method In order to solve these problems, a piezoresistive flexible fabric pressure sensor array system with 32×32 sensing units is first constructed. The causes for the detected abnormal values of the sensing units are then analyzed and the median filtering algorithm is adopted to process the abnormal values in the pressure distribution contour obtained by the system. Aimed at solving the crosstalk phenomenon, a U-Net convolutional neural network model is constructed and the pressure contour generated by the fabric pressure sensor array system is corrected by this machine learning method. In addition, the method for collecting the input and output data set for the model is designed.

Results The results show that the peak signal-to-noise ratio is taken as the benchmark to evaluate the quality of the processed pressure contour image in view of the detected abnormal values of the sensor units. Generally, when the PSNR of the image is greater than 30 dB, the image quality is good. In this paper, the pressure contour of three states, namely, pressure generated with no object, by a cylindrical water bottle, and by cylindrical small medicine bottle, are selected. After the three pressure contours with abnormal values are processed by the median filter algorithm, the calculated values of the peak signal-to-noise ratio are all between 30-40 dB for the three states. The actual processing results reflect the effectiveness of the median filter algorithm. For the crosstalk problem, after 4 200 iterations of training using the input and output pressure contour data sets, the root-mean-square error of the U-Net convolutional neural network model is decreased from over 100 to 7.108, reaching convergence. Under the same pressure exertion conditions by placing palm, foot, cylindrical bottle and rectangular stick on the sensor array, it is shown that the U-Net model can eliminate more effectively the influence of crosstalk by the pressure contours of the fabric pressure sensor array than by the flexible pressure sensor array without crosstalk effect, in terms of the corrected pressure contour.

Conclusion The median filtering algorithm can effectively eliminate the the abnormally detected values by a sensing unit in the flexible fabric pressure sensor array, and the peak signal-to-noise ratio of the pressure contour presented by the flexible fabric pressure sensor array is greater than 30 dB, ensuring contour images with better quality. This also help reduce the manufacturing requirements for the flexible fabric pressure sensor array. The U-Net convolutional neural network can solve the crosstalk problem of the flexible fabric pressure sensor array and eliminate the crosstalk effect while allowing the use of a simple voltage divider circuit to measure the resistance value of the sensing unit.

Objective Madder pigment is a natural dye of bright red color with stable performance. Bio-based polyamide 56 (PA56)is an environment-friendly and excellent bio-based polyamide material. In this research, madder pigment was adopted to dye PA56 fabrics, the dyeing process was optimized,and the dyeing kinetic mechanism was studied. The research results provide a theoretical basis for the application of madder natural dyes to bio-based PA56 fabrics. Furthermore, applying natural dyes to bio-based materials would meet the requirements of circular economy and low-carbon sustainable development.

Method In order to study the dyeing performance of madder on PA56 fabric, the parameters including pH, dyeing time, dyeing temperature and mass fraction of Peregal O were explored to find the optimal conditions. Through K/S value and color characteristics, the influences of mordants and mordant treatment processes were studied. The optimal conditions obtained were subsequently adopted to study the kinetic of madder pigment dyeing. Pseudo first-order and pseudo second-order kinetic models were adopted to examine the mechanism of the adsorption process. Kinetic parameters of madder pigment dyeing on PA56 fiber with different temperature, pH, auxiliaries and mordant were calculated.

Results The results showed that the optimum process for dyeing bio-based PA56 fabrics with madder pigment was as follows: dyeing pH value is 4.2, dyeing temperature is 80 ℃, dyeing time is 40 min and the amount of Peregal O is 1 g/L. After mordant dyeing, the K/S values of the dyed fabrics were significantly increased, and the color characteristics of dyed fabric changes obviously. Compared with the direct dyed fabric, the color fastness of the mordant dyed fabric has been improved. The kinetics of adsorption for different dye temperatures were evaluated by the pseudo first-order and second-order models. A large equilibrium adsorption density difference between the experiment and calculation was observed for the pseudo first-order model, indicating a poor pseudo first-order fit to the experimental data. The experimental data fitted well to the pseudo second-order kinetic model with high correlation coefficient above 0.999. In addition, the C_∞ agreed well with both experiment and calculation, suggesting that the second-order kinetic model well describes the adsorption of madder pigment onto PA56 fiber. The half-dyeing time decreased,and the diffusion coefficient increased with increasing temperature. The influences of dyeing pH, auxiliaries and mordant on the dyeing kinetic parameters were further analyzed. With the increase of pH value, the equilibrium adsorption amount decreased, the half-dyeing time was shortened,and the diffusion coefficient was increased. The addition of sodium sulfate and Peregal O reduced the equilibrium dyeing amount and the half-dyeing time of maddering dye. The rate constant (k₂) and the diffusion coefficient were increased with the addition of sodium sulfate and Peregal O. After mordant dyeing, the equilibrium adsorption amount was decreased, the half-dyeing time increased and the diffusion coefficient decreased, but K/S values of the dyed fabrics were increased.

Conclusion The optimal conditions and dyed fabric with darker color of bio-based PA56 dyed with madder pigment were obtained. The type and mode of mordant can enrich the color tone and improve the color fastness. Fitting calculations reveal that the dyeing process of madder pigment dyeing on bio-based PA56 fabrics conforms to the pseudo second order kinetic model. Madder has a fast adsorption rate on PA56 fabric. The adsorption capacity was dependent with pH value. The addition of sodium sulfate and Peregal O, as well as the pretreatment with mordant, the dyeing processes also conform to the quasi-second order kinetic model.

Objective Among polyester fibers, the black polyester fibers are in great demand. The black polyester fiber produced by conventional printing and dyeing methods is found to have poor color fastness and produce a large amount of printing and dyeing wastewater, but the black polyester produced by dope dyeing can avoid these problems. However, strong mechanical aggregates are formed between the carbon black pigment particles in ethylene glycol-based color paste, and it is difficult to obtain a stable and good glycol-based carbon black pigment suspension and dispersion system. Therefore, it is necessary to modify the carbon black to solve the problem of poor dispersion during the coloring of polyester fiber stock solution.

Method Liquid phase oxidation method was adopted to oxidize carbon black with nitric acid for different time durations (2, 4, 6, 8 h), and the oxidized carbon black was then characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and other instruments to screen out suitable oxidized carbon black. In the presence of dicyclohexylcarbodiimide and 4-dimethylaminopyridine, the 4 h oxidized carbon black was adopted to perform Steglich esterification reaction with ethylene glycol (EG), polyethylene glycol 200 (PEG200), polyethylene glycol 600 (PEG600) and pollyethylene glycol 800 (PEG800) in N,N-dimethylformamide to prepare grafted carbon black, which were named EG-OCB, PEG200-OCB, PEG600-OCB, PEG800-OCB, respectively. according to the graft polymers. The grafted carbon black was analyzed and tested.

Results Through nitric acid oxidation, the particle size of the original carbon black was reduced from 6 686 nm to 156.5-174.9 nm, and the particle size of the carbon black was the smallest with 4 h oxidation. Subsequently, the surface of oxidized carbon black was grafted, and the particle size was further reduced under steric hindrance effect. Compared with the original carbon black, the particle dispersion of oxidized carbon black and grafted carbon black was obvious, and no large aggregates appeared. The oxygen-containing functional groups on the surface of carbon black increased significantly after oxidation. Changing the oxidation time affected the carboxyl content on the surface of carbon black, and the carboxyl content increased with the increase of oxidation time, changing from 0.124 mmol/g to 0.616 mmol/g. It was seen that the diffraction peak of oxidized carbon black did not shift, indicating that nitric acid oxidation of carbon black only occurred on the surface of carbon black without causing serious damage to the carbon black skeleton. The mass loss of grafted carbon black mainly occurred at 40-100 ℃ and 300-450 ℃. The EG, PEG200, PEG600 and PEG800 were successfully grafted onto oxidized carbon black with a 4 h oxidation time duration, with a grafting rate exceeding 33%. The stability test results showed that the heat stability and storage stability of grafted carbon black were above 92% and 93%, respectively. It was found that the deposition of carbon black was not only correlated to the initial particle size, but also to the length of the molecular chain on the surface of carbon black.

Conclusion The average particle size of carbon black decreased significantly after oxidation, and the dispersion effect was the best with 4 h oxidation. The structure of carbon black was not destroyed after oxidation, and the carboxyl content of carbon black increased significantly, from 0.124 mmol/g to 0.537 mmol/g. The surface of oxidized carbon black was successfully grafted with ethylene glycol and polyethylene glycol with different relative molecular weights, and the grafting rate was above 33%. All of them could be stably dispersed in ethylene glycol, and the average particle size was between 132.8 nm and 148.6 nm, among which the average particle size of PEG600-OCB was the smallest. PEG800-OCB has the best storage stability, and the storage stability is above 95%. PEG200-OCB and PEG600-OCB have the best thermal stability, both of which are above 95%. It is dispersed in ethylene glycol to maintain its stability by steric hindrance.

Objective Polyester fabric has many advantages, including good thermal stability, chemical resistance and excellent mechanical properties, which make it widely used in clothing, furnishings and packaging. However, polyester fabric has a low limiting oxygen index and is flammable. When it burns, the polyester fabric produces a large amount of molten droplets which could quickly spread the flames to other combustible materials, and releases a significant volume of toxic smoke. Statistics show that most casualties in fires are caused by smoke inhalation, with more than one-third of total fire casualties directly attributable to smoke poisoning. Therefore, it is crucial to modify polyester fabric to control the release of smoke as well as the formation of molten droplets during combustion.

Method The Schiff base derivative 4-(((4-hydroxyphenyl)imino)methyl)benzene-1,3-diol (HIMB) was prepared and reacted with 9,10-dihydro-9-oxo-10-phosphophenanthrene-10 oxide (DOPO) to obtain a phosphorus- and nitrogen-containing Schiff base derivative flame retardant 4-DOPO-(((4-hydroxyphenyl)amino)methyl) benzene 1,3-diol (DOPO-HAMB). DOPO-HAMB was used as a chain extender to introduce into the molecular main chain of waterborne polyurethane (WPU) to prepare inherently flame-retardant waterborne poly-urethane (FRWPU). FRWPU was then applied to the surface of polyester fabrics through an impregnation method, providing the polyester fabrics with flame retardant properties while ensuring mechanical performance.

Results Photos and scanning electron microscopy images of the actual polyester fabrics before and after the treatment showed that the treated polyester fabric had a slight yellowing compared to the original polyester fabric, with no significant change in transparency. Scanning electron microscopy images showed that the surface of the treated polyester fabric was coated and the gaps between fibers were almost filled. Thermogravimetric experiments demonstrated that the temperature at 5% thermal decomposition, the temperature at the maximum rate of decomposition, and the char yield at 650 ℃ of the treated polyester fabric were all lower than that of the raw polyester fabric. The results of the limiting oxygen index (LOI) and vertical burning tests indicated that the raw polyester fabric had an LOI value of only 17.1%, the WPU treated fabric's LOI was 19.2%, and when DOPO-HAMB was introduced into the WPU molecular main chain, the LOI value of the FRWPU12 (the mass percentage of DOPO-HAMB in WPU is 12%) treated fabric increased to 24.5%, which was 7.4% higher than that of the raw polyester fabric. The raw polyester fabric continued to burn for 18 s after ignition, with a damage length reaching 30 cm, producing dripping that ignites the cotton beneath. However, the FRWPU12 treated fabric did not continue burning and was self-extinguished immediately after removing from the flame, with a damage length of only 9.7 cm and no dripping during combustion. Scanning electron microscopy images and energy dispersive X-ray spectroscopy spectra of the char residue showed that the surface of the char from the raw polyester fabric was fragmented and contained only C and O elements, while the char from the FRWPU3 (the mass percentage of DOPO-HAMB in WPU is 3%) and FRWPU12 treated polyester fabrics was smooth and dense, containing P in addition to C and O, indicating the principal role of P from DOPO-HAMB in the WPU molecular main chain was in the condensed phase. Tensile test of the polyester fabric before and after treatment revealed that the warp and weft breaking strength of the raw polyester fabric were 508 N and 253 N, and the warp and weft elongations at break were 34.0% and 16.9%, respectively. After treatment, the maximum warp breaking strength of the polyester fabric increased to 521 N, and the maximum weft breaking strength to 567 N, with the highest weft breaking at break up to 23.8%. The increase in warp and weft breaking strengths are attributable to the WPU and FRWPU between adjacent fibers, which increased the tightness of the yarns and the connection strength between the yarns. In the water-fastness test, the FRWPU12 treated fabric showed a significantly higher LOI value than the raw polyester fabric even after 50 washing cyeles with water, indicating good water washability of FRWPU12 on the polyester fabric surface.

Conclusion A phosphorus-and nitrogen-containing Schiff base derivative flame retardant, DOPO-HAMB, was synthesized and introduced into the main molecular chain of WPU as a chain extender to obtain FRWPU. The WPU and FRWPU were then applied to the surface of the polyester fabric by an impregnation method. When the mass percentage of DOPO-HAMB in WPU is 12%, the LOI value of the treated fabric reaches 24.5%, the length of damage in the vertical burning test is significantly decreases, and no dripping occurs during combustion. Compared with the raw polyester fabric, the warp and weft tensile breaking strength of the treated polyester fabric are improved to a certain extent. Moreover, the LOI value of the treated polyester fabric after 50 washing cycles remains significantly higher than that of the raw polyester fabric, demonstrating good water washability.

Objective Cotton fabric is one of the most common natural fabrics, and has excellent moisture absorption, breathability, thermal insulation and softness, which are widely used in clothing, household tems, military and other fields. Unfortunately, the limiting oxygen index of cotton fabric is only 18 %, and it is easily ignited in the air, causing fire accidents. In addition, the flame retardant durability of flame-retardant cotton fabrics is also very important. Hence, it is necessary to prepare efficient and durable flame-retardant cotton fabrics.

Method The ammonium phosphate (AHPA) flame retardant was prepared from phosphorus pentoxide and ethanolamine. The P/N-type flame retardant AHPA was heated to produce acidic substances such as polyphosphoric acid, which promoted the dehydration of the fabrics and formed a dense carbon layer. During this process, P/N-type flame retardant AHPA generated non-flammable gases, which isolated heat and oxygen, diluted combustible gases, and hindered flame spread. Flame retardant cotton fabrics were prepared by common rolling-baking-baking finishing process. The thermal stability and mechanical properties of flame retardant cotton fabrics were analyzed by vertical flammability test, limiting oxygen index test, thermogravimetric test, cone calorimetry test and universal material test.

Results The test results showed that the flame retardant AHPA was successfully synthesized,and the fiber surface had been successfully covered by the flame retardant. When the concentration of flame retardant AHPA was set to 300 g/L, the LOI value of flame retardant cotton fabric had been increased to 52.9 % from 18 %, with only 45 mm damaged carbon length. The heat release rate and total heat release of the treated cotton fabrics were decreased by 86.1 % and 31.5 %, respectively. The flame spread rate (FIGRA) and mean effective heat combustion (Mean-EHC) were decreased from 6 kW/(m²·s) and 23.5 MJ/kg to 0.3 kW/(m²·s) and 15.3 MJ/kg, respectively, representing 95 % and 34.9 % reductions in each perspective. The AHPA flame retardant worked to reduce the heat release and the combustion efficiency with improved safety. In nitrogen and air atmosphere, the carbon residue of flame-retardant cotton fabrics had been greatly increased compared to the pristine cotton fabric, indicating that the thermal stability of the flame-retardant treated cotton fabrics had been greatly improved. The breaking force of the finished cotton fabrics was decreased in both warp and weft directions. After 50 washing cycles, the LOI value of the flame retardant cotton fabrics maintained at about 31.6 %.

Conclusion In summary, the flame retardant AHPA endows cotton fabrics with efficient and durable flame retardant properties, self-extinguishing of fire, discontinuous smoldering phenomenon, and excellent washing durability. The flame retardant AHPA can be applied to cotton fabrics used for bedding, carpets, curtains and so on. In following-up research work, the mechanical strength of the flame retardant cotton fabrics needs be optimized, and the total smoke release should be reduced.

Objective Pickering emulsion uses solid-particles as emulsifier instead of small-molecule surfactants, in which solid particles are embedded on the surface of emulsion droplets, and thus its interfacial adsorption energy is far greater than the thermodynamic energy of the solid particle Brown motion. Consequently, it is difficult for the solid particles to escape from the oil-water interface, providing the emulsion with excellent storage stability. Pickering solid emulsifier in the paraffin emulsion does not cut down the paraffin crystalline temperature, and eliminates the subcool phenomenon, and improves its phase-change energy storage performance. Unfortunately, very few Pickering emulsifiers have existed, such as nano-silica, graphene oxide, nano-cellulose crystals, more often being applied with organic polymer co-emulsifier.

Methods Soap-free emulsion polymerization was carried out with styrene (St) and methacryloxyethyl-trimethylammonium chloride (DMC) as monomers, divinyl benzene (DVB) as crosslinker, ethanol as auxiliary solvent. Cationic copolymer particles characterized with monodispersity, clean surface, and designed size were obtained. The paraffin Pickering emulsions and paraffin droplets on viscose fabric phase change materials (Vis-PCM) were prepared by using the resultant copolymer nanoparticles (P(St-co-DMC)). The microstructure and properties, monomer conversion, nanoparticle size, Zeta potential and contact angles of P(St-co-DMC) particles as well as Vis-PCM were investigated by Fourier transform infrared spectrometry, scanning electron microscopy, thermogravimetry, differential scanning calorimetry, and contact angle goniometry.

Results The influences of DMC and initiator dosages, and ethanol contents on the monomer conversion and the nanoparticle size, as well as of DMC dosages on the contact angle and Zeta potential of the nanoparticles were studied. The results showed that cationic P(St-co-DMC) copolymer nanoparticles were successfully prepared, and the two major monomers were merged into the copolymer chain. The resulted polymers were shown to withstand the thermal shock during emulsification process, as well as phase change energy storage and heat release recycling processes. The monomer conversion presented bell-shape behavior, whereas the particle size and its dispersion index showed reversed bell tendency with the increases of DMC, initiator and ethanol. However, the Zeta potential of the copolymer particles initially soared up and then tended to be constant, whereas the hydrophilicity was improved with the increase of DMC dosage. When the amounts of DMC, KPS and ethanol were fixed at 25%, 2.5% and 15%, respectively, the monomer conversion reached 83%, the size, the Zeta potential, and the surface contact angle of the resultant copolymer particles were 114 nm, 47.2 mV, and 58°, respectively. The over three-month shelf life, oil-in-water paraffin Pickering emulsion at the oil-to-water volume ratio of 3∶1 and at the droplet size of (4.4±0.5) μm was eventually obtained. The phase change latent heat of Vis-PCM, which was obtained by impregnating spunlaced viscose nonwoven fabric into the Pickering emulsion, reached up to 139.3 J/g, and the paraffin leakage rate of Vis-PCM was only 0.6% after 20 thermal cycls.

Conclusion Copolymer particles with controllable surface features such as water contact angle, particle size and electricity, instead of the small molecule surfactant, can be adsorbed firmly at the oil-water interface to obtain a long shelf life Pickering emulsion. P(St-co-DMC) emulsifier copes with the paraffin subcool phenomenon due to small molecule surfactant plasticizer based on heterogeneous nucleation mechanism. Also it is emulsion droplets rather than de-emulsified paraffin bulk that adhere to the nonwoven surface, which ensures the paraffin-microencapsulated fabric acting as reusable phase change energy storage materials. All the results confirm that P(St-co-DMC) possesses excellent emulsifying ability, and Vis-PCM has good heat storage and heat release properties.

Objective In order to solve the problem that printing and dyeing wastewater is harmful to the environment and difficult to treat, this research aims to prepare an economical and environmentally friendly adsorbent with excellent adsorption effect, and the adsorption performance of ZIF-8 on azo dyes represented by anionic Congo Red dyes was investigated.

Method In this research, 2-methylimidazole and Zn(NO₃)₂·6H₂O were used as raw materials, and deionized water was used as solvent. The proportion of 2-methylimidazole, Zn(NO₃)₂·6H₂O and deionized water was adjusted and they mixed by mechanical stirring to prepare the homogeneous and clear particles of zeolitic imidazolate framework-8 (ZIF-8) material under normal temperature and normal pressure conditions. The structure of the ZIF-8 material was tested by scanning electron microscopy(SEM), infrared spectrometry, X-Ray diffraction, thermogravimetry, BET and other characterization methods. The adsorption performance of the material on dyes was evaluated by the water-bath constant-temperature shaking method, and the factors affecting the adsorption and the adsorption mechanism were analyzed.

Results It was found from SEM images that the ZIF-8 section was smooth, and that the particles were uniform and had a polyhedral structure. Infrared spectra analysis and X-Ray diffraction results showed that the ZIF-8 material was consistent with the finding reported in docoments. Thermogravimetric analysis and specific surface area tests revealed that the thermal cleavage temperature of the ZIF-8 material was 258 ℃, and the ZIF-8 had a good thermal stability. The specific surface area of BET was 869.63 m²/g, the specific surface area of Langmuir was 1 140.03 m²/g, and the average pore size was 3.27 nm. The adsorption equilibrium was reached in a shorter time at the lower initial concentration, and the adsorption amount reached the maximum when the initial concentration was 95 mg/L. It was found that the adsorption would first rise, then fall and finally tend to equilibrium with the increase of ion concentration, and the adsorption amount could reach the maximum when pH was neutral. It was also revealed that the adsorption rate of ZIF-8 could still be maintained at 69% after 4 cycles. The adsorption of ZIF-8 on Congo Red was more in line with the pseudo-second-order model through the fitting of kinetic model, which was dominated by chemical adsorption. The adsorption isotherm model fitting showed that the adsorption of ZIF-8 on Congo Red was in line with the Langmuir model, which belonged to the adsorption of the monolayer molecules. It was believed that the whole adsorption process was an exothermic reaction, and the low temperature was favorable for the adsorption. Under the conditions of 20 ℃ and pH=7, the adsorption effect of ZIF-8 on 95 mg/L Congo Red solution was the best, and the maximum adsorption rate was 671.41 mg/g.

Conclusion ZIF-8 prepared using deionized water as the solvent is found to reduce cost compared to the situation with methanol as the solvent, and the operation is simple and safe compared to other preparation methods. The ZIF-8 particles prepared are uniform and clear, with good thermal stability and large specific surface area. ZIF-8 has better adsorption performance on anionic dyes represented by Congo Red, so it can be applied to the treatment of general anionic dye waste liquid.

Objective With the development and application of flexible sensing technology, there is an urgent need for accurate evaluation of detected results, because there is no mature evaluation standard at present. For the fabric-type sensors, the output of its detection signal is closely related to the changing curvature of the human surface and the physical parameters of the material itself. Therefore, this study attempts to establish a continuous dynamic pressure finite element model for the interface between the human body and clothing, soas to provide theoretical basis for assessing the output accuracy of the fabric-type sensor. It could be used to characterize the accuracy of flexible sensing technology in practical application, so as to further promote the industrialization of smart wearable products.

Method In this research, the human arm is selected as the research object, and a three-dimensional finite element model of the human arm and the elastic pressure arm sleeve is established, based on the finite element principle. The processes of putting the elastic cuff around the human arm and the buckling of the human elbow joint after wearing the elastic arm sleeve are numerically simulated, and the equivalent stress of the soft tissue external surface of the human arm and the elastic pressure arm sleeve changing with time is calculated. Based on the data, a linear regression model was established, and root-mean-square error (RMSE) was selected as the representation index of the linear regression model to characterize the accuracy of the textile flexible sensor test.

Results In order to simplify the model, the fabric and bone were assumed to be isotropic linear elastomer, and the soft tissue was assumed to be isotropic hyper-elastomer. When the pressure arm sleeve was worn to the human arm, 16 points were determined according to the shape of the pressure arm. The effectiveness of the model was verified, and the relative error between the simulated value and the measured value was analyzed. The results showed that except for the outer part of ulna at the lower end of the arm (height 1-t side) and the muscle of the upper arm (height 4-p side), the finite element prediction results of the remaining 15 test points under three different fabrics were basically consistent with the pressure experiment results (0.2% to 8.9%), which can prove the validity of the model. Two types of textile flexible sensors were selected in the market, and the mechano-electric coupling model of the flexible sensors was established, and the electrical signals collected by the sensors were converted into stress values. The dynamic stress curve of the soft tissue surface on the outside of the elbow joint was extracted with time. Linear fitting was carried out according to the feature points, and the fitted curve was used as a linear regression model to characterize the application performance of the collected test data at the elbow joint. The RMSE was selected as the representative index of the regression model, and the accurate performance of the output signal applied to the elbow joint of the two sensors was characterized. The results showed that the regression effect of sensor A was better than that of sensor B. In other words, sensor A is more suitable for the measurement of elbow joint flexion with higher accuracy, indicating that this model could potentially characterize the performance of test accuracy of fabric-type flexible sensors.

Conclusion This paper proposes a method to characterize the accuracy of test data from textile flexible sensor. A finite element method was established to simulate the dynamic pressure of clothing, and a linear regression model was set up to calculate the dynamic pressure using RMSE to characterize the prediction error. For the future research, it is suggested that the establishment of materials and models can be further refined for different parts of the human body to balance the calculation time and get closer to the physiological characteristics of the human body. In order to simulate more complicated working conditions, it is necessary to further understand the biomechanics of the human body in the state of motion. In addition, it is necessary to explore the dynamic pressure model of clothing under multi-physical field coupling to better characterize the performance of fabric-type flexible sensors in practical applications.

Objective Immersion suit is a type of personal protective equipment to prevent cold shock or even death caused by rapid heat loss when the wearer accidentally falls into cold water, which can effectively prolong the survival time of the wearer. The existing immersion suit has good thermal insulation, but there may be physiological heat load during the non-water state. Therefore, the development of protective clothing capable of dynamically adjusting thermal insulation to provide thermal comfort in different operating environments is necessary. The performance evaluation under pressure conditions is also in demand.

Method An air inflatable temperature-regulating immersion suit was developed, containing an inflatable layer with adjustable static air volume, between the waterproof layer and the aerogel thermal layer. The thermal insulation of the developed air inflatable immersion suit and the commercial immersion suit with polyester wadding were measured and compared using thermal manikin "Newton". The total and local thermal insulations were analyzed under conditions of two thermal insulating materials (aerogel and polyester wadding), three pressure states (no pressure, low pressure, high pressure), and four inflation volumes (CON, 1/3FULL, 2/3FULL and FULL). The thermal insulations were calculated using the parallel method and statistically analyzed using SPSS software.

Results The experimental results showed that the thermal insulating materials had significant effect on the total thermal insulation of immersion suit under no pressure. The thermal insulation of the air inflatable immersion suit was 3.85 clo, which was significantly higher than that of the polyester wadding immersion suit whose a thermal insulation is 3.28 clo (P<0.01). Meanwhile, the total thermal insulation was significantly reduced under high pressure. The thermal insulation of the air inflatable immersion suit was significantly higher than that of the polyester wadding immersion suit at the forearm, chest, abdomen, back, and buttocks (P<0.01), while the differences in other areas were not significant. With the increase of pressure, the total thermal insulation of the immersion suit was decreased, and the reduction rate of air inflatable immersion suit was 11.53% from no pressure to low pressure and 24.40% from low pressure to high pressure, with the reduction rate of thermal insulation from no pressure to high pressure for the commercial immersion suit being 7.05%. The difference of thermal insulation between the two immersion suits was no longer significant. This may be related to the fact that the immersion suit was squeezed, reducing its overall thickness and damaging the warmth wadding and the static air layer underneath the suit. The pressure also reduced the local thermal insulation. Under low pressure, the thermal insulation of the air inflatable immersion suit was decreased less at the upper arm and the back. Under high pressure, the thermal insulation of the abdomen, back and buttocks was decreased remarkably, and there was no longer a significant difference between the two suits at the abdomen and thighs. This result is related to the degree of extrusion of the air layer under the clothing. When the thermal manikin is standing still, there is more air under the clothing in the lumbar and abdominal areas, and less air under the clothing in the shoulders and hips, and consequently a greater decrease in the thermal insulation of the lumbar and abdominal areas when it is extruded by an external force. With the increase of the inflation volume, the total thermal insulation did not change significantly under no pressure, was increased significantly (P<0.05) and then decreased slightly under low pressure and continued to increase under high pressure. This may be be cause of the fact that immersion suit contained a certain air layer between the layers, and the increase in inflation without pressure instead squeezes out the presence of the air layer, and no difference exists in the total thermal insulation. Pressure causes the air layers between layers and underneath the suit to be squeezed, but inflation resists the squeezing of the air layers caused by pressure, so the higher the inflation, the greater the thermal insulation of the suit. However, the inflation volume did not have a consistent pattern of influence on the local thermal insulation for the air inflatable immersion suit.

Conclusion The total thermal insulation and local thermal insulation of the two immersion suits were decreased under pressures, and the reduction was more pronounced as the pressure became higher. The difference between the thermal insulation of the two immersion suits was no longer significant, but the air inflatable immersion suit was still better than the commercial immersion suit. Under pressures, the thermal insulation of the air inflatable immersion suit tended to increase with increasing inflation volume, and the higher is the pressure, the more pronounced is this trend. In summary, compared with the commercial immersion suit, the air inflatable immersion suit provided better thermal insulation and could dynamically adjust under a certain pressure.

Objective Video generation based on a single dress image has important applications in the fields of virtual try-on and 3-D reconstruction. However, existing methods have problems such as incoherent movements between generated frames, poor quality of generated videos, and missing details of clothing. In order to address the above issues, a generative adversarial network model based on pose embedding mechanism and multi-scale attention links is proposed.

Method A generative adversarial network (EBDGAN) model based on pose embedding mechanism and multi-scale attention was proposed. Pose embedding method was adopted to model adjacent frame actions and improve the coherence of video generated actions, and attention links for each resolution scale feature were added to improve feature decoding efficiency and generate image frame fidelity. Human parsing images were utilized during the training process to improve the clothing accuracy of the synthesized images.

Results The learned perceptual image patch similarity (LPIPS) and peak signal-to-noise-ratio(PSNR) values indicated that the generated results of EBDGAN were closer to the original video in terms of color and structure. From the motion vector(MV), it was seen that the video generated by EBDGAN from a single image moved less between adjacent frames and had higher similarity between the two frames, leading to more stable the overall videos. Although the structure similarity index metric(SSIM) score was slightly lower than (CASD), this method was more efficient as it only requires image and pose information as input. In some frames where the characters were far from the camera, EBDGAN retained the details of hair and shoes. In some frames where the characters are closer to the camera, the front clothing image of EBDGAN retained the collar and hem, such as the collar of the left image in the second row and the hem of the right clothing. When the characters in the video turned around, EBDGAN did not cause the characters in the video to exhibit strange pose or lose some body parts, but instead generated a more reasonable body shape. The results of the ablation experiment showed that the complete model can efficiently utilize the pose information and features of the input image to guide video generation. Blocking any network component will result in a decrease in model performance. The results of EBDGAN-1 indicated that multi-scale attention linking could help networks generate images with more reasonable distribution. The MV of EBDGAN-2 suggested that when the attitude embedding module was added, the relative movement between adjacent frames was smaller, resulting in high video stability.

Conclusion This article proposes a method for generating videos from single images based on pose embedding mechanism and multi-scale attention linking. This method uses the pose embedding module EBD to model the pose between adjacent frames in the time series, reducing the number of parameters while ensuring the coherence of actions between adjacent frames. By using multi-scale attention linking, the efficiency of feature extraction is improved, further improving the quality of video generation. Using character analysis images as auxiliary input enhances the expressive ability of character clothing. The prosposed method was experimentally validated on a public dataset, with SSIM 0.855, LPIPS 0.162, PSNR 20.89, and MV 0.108 4. The ablation experiment proves that the model proposed model can help the network achieve better performance in video generation tasks. Comparative experiments have shown that the proposed method offers better stability in generating videos and more realistic character details.

Objective In order to solve the problems of slow speed, low efficiency, and high cost in conventional manual quality inspection methods for sewing thread, this study proposes a machine vision-based method for sewing thread defect detection in seams. This study aims to achieve fast, accurate, and automated identification of common defects such as cast thread, jumper thread, and broken thread in seams. This study also highlights the importance and necessity of improving product quality and production efficiency in the textile and garment industry.

Method This study adopts a two-step approach for defect detection. Firstly, a low-cost array camera was adopted to capture real-time images of the sewing seam and the DeblurGAN-v2 method was employed to remove motion blurriness from the images, aiming at improving image clarity. Secondly, the student-teacher feature pyramid matching method was applied for anomaly detection, which transfers the knowledge from a pre-trained ResNet-34 model as the teacher network to a student network with the same architecture, so as to learn the distribution of normal images. By comparing the differences between the feature pyramids generated by the two networks as a scoring method, the defect detection system made decisions on whether the image has anomalies, and marked the abnormal areas with a heat distribution map.

Results The defects of flat stitch fabric and overstitch fabric were tested and the performance of the proposed method was evaluated in terms of recall and accuracy rates. The results show that the proposed method can effectively detect various sewing thread defects and has high recall and accuracy rates for different types of defects. This study also provided some examples of defect detection results and scores for different types of defects.

Conclusion The feature pyramid matching technique is applied in the field of stitch trace detection. By adding the difficult sample mining technology, the average detection accuracy is increased to more than 95%, and the detection speed of a single image is less than 0.04 s. Aiming at image motion blur ring caused by jitter and fast movement. The DeblurGAN-v2 framework is used as the framework of deblurring algorithm, and the blueprint convolution is added to change the backbone network, and the processing speed of a single image is kept below 0.06 s. The model has excellent interference resistance and high processing speed, and can meet the requirement of stitch trace recognition.

Objective This research aims to investigate the potential application of aerogel composite materials for enhancing the thermal insulation performance of dry diving suit liners underwater. Through meticulous experimentation conducted at both fabric and garment levels, this research aims to assess the thermal insulation capabilities, tailored for garment application. Employing sophisticated seam-sealing techniques, the behavior of these materials under compression in underwater conditions are to be simulated to evaluate alterations in thermal insulation performance. This comprehensive methodology seeks to elucidate the optimal utilization of aerogel composite materials, providing valuable insights into enhancing thermal insulation in diving suits, particularly in the challenging low-temperature, high-pressure environments often encountered during underwater operations.

Method Experimental samples consisted of various aerogel composite materials known for their lightweight and superior thermal insulation properties. These are in the forms of foam, nonwoven fabric, and flake-type aerogel composites, along with a conventional polyester fiber cotton, specifically the C-type Thinsulate from 3M Corporation, used in dry diving suit liners. Fabrication involved combining these materials into a three-layered fabric system, maintaining consistency in outer and inner layer materials. Testing methodologies included sweating hot plate experiments for thermal resistance assessment and simulated compression design to simulate underwater pressure conditions. Additionally, sweating manikin method and underwater human subject trials were conducted to evaluate insulation performance in practical scenarios.

Results Thermal performance analysis provided valuable insights into the behavior of various fabric systems. Significant thickness variations were observed among the samples before seaming, with flake-type materials displaying the highest initial thickness due to their relaxed state. After seaming, these materials experienced substantial thickness reduction, indicating their susceptibility to compression. Conversely, non-woven and foam-type materials exhibited minimal thickness variation, suggesting their resilience to compression by virtue of inherent elasticity and structural composition. Regarding thermal resistance, considerable diversity was noted among fabric samples pre-seaming, with flake-type materials demonstrating higher thermal resistance compared to others. However, post-seaming, the thermal resistance disparity diminished significantly. This reduction was particularly pronounced in flake-type fabrics, suggesting a decrease in insulation capacity due to fiber compression and air expulsion. Conversely, multilayer fabric systems comprising aerogel composites exhibited enhanced thermal resistance post-seaming, indicating their potential for improved insulation performance in underwater conditions. Furthermore, the evaluation of thermal clothing insulation performance yielded promising outcomes. Combining aerogel composite materials in drysuit thermal liners resulted in higher total thermal resistance compared to conventional polyester fiber cotton liners. Additionally, the multilayer fabric system composed of aerogel composites demonstrated superior thermal resistance under compression, suggesting enhanced insulation efficacy in underwater environments. During underwater dressing experiments, divers maintained stable core body temperatures above 37 ℃, despite the water temperature being 14 ℃ while experiencing decreasing skin temperatures over time. Notably, thigh skin temperature exhibited the fastest decrease, attributed to lower metabolic heat production and increased heat dissipation. Overall, the aerogel composite material thermal liner demonstrated excellent insulation performance, highlighting its potential for use in underwater garments. The findings emphasized the promising prospects of aerogel composite materials in enhancing insulation performance in underwater environments. These materials offer thinner and more effective thermal clothing solutions compared to conventional materials, paving the way for advancements in underwater garment design and performance.

Conclusion The study reveals the favorable suitability of selected aerogel composite materials underwater, with flake-type aerogel composites demonstrating optimal performance. Despite lower initial thermal resistance compared to C-type Thinsulate polyester fiber cotton in natural conditions, aerogel composites exhibit similar thermal resistance under compression, indicating their suitability for underwater high-pressure environments. Foam-type and non-woven aerogel composites show minimal thermal resistance differences before and after seaming, with foam-type materials exhibiting deformation-related variations. The assembled aerogel composite thermal liner demonstrates excellent insulation performance, maintaining core body temperatures above 37 ℃ during underwater experiments, thereby ensuring diver safety during subaquatic operations, despite the challenging water temperature of 14 ℃ encountered during these underwater experiments. The study provides valuable data for selecting and applying insulation materials in underwater high-pressure environments, offering new solutions for diver protection and influencing the development of underwater protective clothing.

Objective In order to improve the friction and wear properties, prolong the service life of the steel collar and increase the efficiency of the steel collar in ring spinning machines, the friction and wear mechanism of diamond-like coating (DLC) on spinning steel collar at high temperature was studied, and the friction and wear resistance caused by the structure change of diamond-like coating was analyzed. In the actual running state, the force of diamond-like coating applied on the steel collar was analyzed, and the performance of diamond-like coating was studied through the maximum force value and the maximum deformation.

Method Cr-doped DLC coating was prepared by low temperature physical vapor deposition (PVD) coating technology on the surface of 20# steel. The surface morphology of DLC coating was studied using scanning electron microscope. The structure composition of DLC coating was analyzed by X-ray diffraction, energy spectrum and Raman spectrometer. Nanoindentation tester was a dopted to test the mechanical properties of the coating. High temperature friction and wear testing machine was a dopted to test the friction performance of the coating at different temperatures (25, 100, 200, 300 ℃), and the influence of the force on the friction process of the steel collar was analyzed by simulation.

Results From the friction test at different temperatures, the average friction factor of 20# and 20#-DLC samples were found to firstly increase and then decrease as temperature increased. At 300 ℃, 20# generated oxides, with a large amount of oxides formed an adhesion layer. The average friction coefficient was reduced to 0.54. The graphitization of 20#-DLC samples occurred at 200 ℃ and 300 ℃, forming a transfer layer dominated by carbon elements, and the transfer film replaced the attachment layer. The friction changed from coating to attachment layer to coating to transfer layer, and the average friction coefficient at the two interfaces was decreased to 0.145 and 0.107, respectively. DLC coating not only showed excellent anti-friction effect, but also reduced the stress and deformation in the process of friction. Through simulation analysis, the maximum stress value and maximum deformation of the steel collar after deposition of DLC coating were 4.20×10⁸ MPa and 1.47×10^-2 mm, respectively in actual operation.

Conclusion The DLC coating doped with Cr element was prepared on the substrate by low temperature PVD coating technology. The elastic modulus and hardness were 205.8 and 23.66 GPa, respectively. The coating surface showed honeycomb structure and amorphous structure. The average friction factors of 20# steel sample at 25, 100, 200 and 300 ℃ are 0.05, 0.62, 0.64 and 0.54, respectively. The average friction factors of 20#-DLC samples at 25, 100, 200 and 300 ℃ are 0.053, 0.213, 0.145 and 0.107, respectively. Under the same temperature conditions, the friction factor curve of 20#-DLC sample is significantly lower than that of 20# sample, and the DLC coating forms a transfer layer dominated by carbon elements at 200 ℃ and 300 ℃, which reduces the friction factor. DLC coating has excellent anti-friction properties and is suitable for textile steel collar working at high temperature. In the process of friction and wear, the two types of steel collar (20# and DLC-20#) showed different degrees of stress concentration and deformation at the lower right corner of the runway under the action of external forces. The maximum stress value and deformation amount of 20#-DLC are 4.20×10⁸ Pa and 9.69×10^-3 mm, respectively. The deformation of DLC coating absorbs part of the energy brought by the stress, which reduces the maximum stress value and deformation amount of the steel collar matrix.

Objective In the automatic production line of circular weft machines in knitting workshops, the identification of the residual yarn quantity of the spindle was the prerequisite and key to realizing the automatic loading and unloading of the spindle. The detection result of spindle residual amount was easily affected by many factors, such as background spindle, spindle type, yarn crease structure and so on. In order to ensure the accuracy and real-time performance of the information of spindle residual yarn quantity of yarn frame, a machine vision-based online detection technology of spindle residual yarn quantity was studied.

Method The improved Yolov5 model was adopted to detect the residual yarn quantity in a spindle, and the intercepted end picture of the spindle is extracted through perspective transformation, pixel average, contour detection and other operations to extract the inner and outer circle contours of the spindle. The circle fitting algorithm based on gradient descent designed in this paper was then adopted to fit the inner and outer circles of the spindle and obtain the inner and outer circle radii of the spindle. Finally, the principle of small-hole imaging was adopted to convert the pixel difference of the spindle into the actual residual yarn quantity.

Results In terms of model recognition, performance comparison of the three models showed that the model accuracy could be improved by 0.24% simply by improving the Yolov5 backbone network, and the accuracy could be further enhanced by 0.27% by incorporating the Shuffle-Attention mechanism. As for residual yarn quantity detection, detecting the residual yarn quantity demonstrated that the detection error of this algorithm was less than 3 mm, outperforming the Hough circle algorithm. With regards to the dataset, in order to cater to the practical production needs of factories, this paper created a dataset comprising spindles from the actual production process of factories.

Conclusion A method combining the improved Yolov5 with conventional image processing was proposed for sindle residual yarn quantity detection in the automated production line of circular weft machines. First, the spindle image was segmented using the enhanced Yolov5 model. Then, the segmented spindles image was processed by perspective transformation and end-face pixel averaging to effectively extract the inner and outer circular contours of the spindle. The circle fitting algorithm designed in this paper was utilized to fit the inner and outer circles of the spindle to complete the calculation of the residual yarn quantity the spindle. The improved YOLOv5 residual yarn quantity detection algorithm for spindle utilized an enhanced network structure and dataset. Therefore, it could be effectively applied to the on-line detection of residual yarn quantity in the spindle. It provided ideas for future applications in embedded devices.

Objective The single-station needling machine has low preform production efficiency. The existing linear double-station needling robot equipment occupies a large space, and both double stations are equipped with external rotary axes, ausing system programming difficult. A linear/rotary hybrid switching double-station needling robot system was proposed, with the function of automatic preform changing for efficient needling of large-size quasi-rotary composite preforms. The design of the double-station needling robot is aimed at automatic change of preforms while ensuring that the equipment occupies a small space with the reduced use of external rotary axes to ensure convenient programming of the system.

Method The mechanical structure design, design of quasi-rotary preforms mold and needling process, control system design, motion simulation and experimental verification of the double-station needling robot system were carried out. The double-station involved needling station and a layup station. The motor on the needling station was linked to a 6-joint mechanical arm, and system had only one external rotation axis. Within the rated load range of the robot arm, the number of needles of the needling robot effector was increased and the carrying capacity of the CNC rotary table was further improved to meet the needling molding of large-size preforms.

Results The double-station needling robot consisted of a 6-joint mechanical arm, a needling robot effector, and a double-station working platform. The robot arm controller model was Kawasaki E02/7.5 kW with rated end load of 50 kg. The needling robot effector had 25 needles using a TK13500EL CNC rotary table with a maximum allowable inertia of 19 kg/m² and a maximum allowable driving torque of 1 430 N·m. The experimental results demonstrated that the double-station needling robot system was able to fabricate successfully quasi-rotary composite preforms. The actual needling trajectories in the experiment were highly consistent with the simulated needling trajectories. In the system, the bearing capacity of the CNC rotary table was improved and the number of needles in the needling robot effector was increased to 25ss, which met the need for needling of large-size preforms, and the needling efficiency was double folded. The system facilitated the automatic preform changing, enabling the workers and needling robot to efficiently cooperate in production. The downtime of the robot after the needling of each unit layer was shortened from the existing 1 h to 1 min., and the needling production efficiency had been greatly improved. In addition, the linear/rotary hybrid switching method made it possible for the double-station working platform to occupy a small working space with a compact structure, providing enough distance between the raw material laying station and the robot needling station, ensuring the safety of raw material laying personnel.

Conclusion This paper presented a linear/rotary hybrid switching double-station needling robot system for efficient manufacturing of large-size quasi-rotary composite preforms. By increasing the carrying capacity of the CNC rotary table and the number of needles of the needling robot effector to 25, the system can achieve needling of quasi-rotary preforms with a height of 1.5 m and a diameter of 1 m. The needling trajectory on the surface of the experimentally prepared preform was highly consistent with the simulated needling trajectory, and the needling efficiency was double folded by virtue of the increase in the number of needles. The setting of double-stations made the automatic change of preforms possible, and the workers and the needling robot could efficiently collaborate in production, which greatly improved the efficiency of needling production. The linear/rotary hybrid switching method made the double-station working platform occupy a small working space with a compact structure. In the double-station, only the external rotary axis on the needling station was linked to the 6-joint mechanical arm. The system was relatively simple and the programming was convenient.

Significance Excesive consumption of petroleum-based synthetic fibers limits the sustainability of textile industry. It is urgent to find low-cost renewable biomass resources to replace convenitional petroleum resources. Due to the quick expansion of fast fashion, the amount of waste wool grows every year. In addition, waste wool is normally disposed through incineration or landfill, which is not conducive to economic development and causes severe secondary pollution to the environment. Keratin is the major component of wool, which has excellent mechanical stability, shape memory properties, piezoelectric properties, biological activity, biodegradability, biocompatibility, and adsorption properties. Thus, keratinous material extracted from waste wool can be applied to produce high-value applications such as functional finishing agents, thermal and sound insulation materials, flexible electronic devices, biomedical applications, or adsorption materials. The regeneration technology of keratin effectively contributes to the sustainable development of wool resources, which triggered dramatically interest in recent years.

Progress This review mainly reports the regeneration techniques of keratin, which includes the methods of extraction and recent high-value applications in the form of fibers, membranes, gels, and scaffolds. The common methods of keratin extraction primarily include physical, chemical, and biological methods. Owing to precisely destroying disulfide bonds and hydrogen bonds, chemical methods, such as reduction, oxidation, ionic liquid, and deep eutectic solvent methods, are widely applied. The reduction methods effectively preserve the secondary structure of keratin, and the free sulfhydryl groups generated after extraction can be reconstructed in the subsequent process to cross-link keratin chains, thus perfectly restoring the hierarchical structure in fibers. However, keratinous materials are normally brittle due to poor mechanical properties. In previous work, researchers had demonstrated that 1,4-dithiothreitol can effectively modulate the viscoelastic spinning dope and act as a bridge in the keratin chains. After the drafting in wet spinning, fibers were induced to rearrange to the secondary structure. The regenerated keratin materials with excellent mechanical properties have extensive application prospects, which mainly include flexible electronic devices (such as humidity sensors, conductive composites, gel electrolytes, and so on), biomedical productions (such as wound healing, hemostasis, drug release carriers, tissue engineering, and so on) as well as adsorption applications.

Conclusion and Prospect The regenerated techniques of waste wool keratin and its high-value applications receive a lot of attention, promoting the transformation of biomass resources into the valuable materials. However, there are still some challenges that prevent its further practical and commercial production, such as poor mechanical properties, toxicity of chemical reagents, higher cost, and non-environmentally friendly disposal techniques. In-depth investigations on keratin extraction techniques not only can ensure high extraction rate, but also guarantee integral secondary structure of keratin chains. For the extraction techniques, ionic liquids, and green reducing agents such as cysteine, glutathione, and lower toxic 1,4-dithiothreitol gain widespread attention. In addition, chemical methods to enhance the extraction rate of keratin can be assisted by ultrasonic or microwave treatment. A dearth of information regarding the improvement of mechanical property has far limited the process of industrialization. It is also suggested that further investigations are required to gain high molecular weight keratin, find eco-friendly cross-linking agents, increase the orientation and crystallinity of the prepared fibers. In order to reduce purification cost in the biomedical applications, researches should use green and environmentally friendly reagents in the extraction process. The rapid development of keratin regeneration techniques can greatly promote the recycling of biomass resources, and sustainable economic development.

Significance Fungi are neither plants nor animals, which are one of the first life forms on Earth. Fungi are widely distributed in nature, with millions of species. In recent years, with the improvement of people's awareness of environmental protection and the progress of cultivation technology, the application of fungi is also expanded. Fungi are rich in dextran and chitin, and have unique physical and chemical properties. Besides food and medicine, fungi are also widely used in material engineering. Fungal composite materials are a new type of environment-friendly material, which has the characteristics of simple production, complete degradation, durability and wide application scenarios which attracted much research interest. In order to promote the development of sustainable materials and advocate the concept of environmental protection, it is of great significance to review and summarize the current research status of fungi and mycelium composites.

Progress In order to better promote the development of fungal composites, this paper makes a comprehensive review of the current fungal materials covering the composition, fermentation mode and application status. The main structure, composition, active substances and application value of large fungi such as oyster mushroom, Flammulina mushroom and Ganoderma lucidum were first introduced respectively. In order to make the explanation clearer and more concise, some detailed data about fungi materials were collected. Fermentation methods also have a great influence on the properties of raw fungal materials. Fermentation products could have different thickness and density, requiring different processing routes. Therefore, the advantages and disadvantages of solid fermentation and liquid fermentation were compared and analyzed, and their effects on the processing properties of raw fungal materials were summarized. In addition, the research progress of pure mycelia materials and mycelium composites was comprehensively reviewed. At present, the research and development of fungal materials still show rapid growth. Mycelia composite materials have applications in sound insulation materials, building boards, packaging materials, textile leather and medical dressings, and so on. Fungal materials are rich in chitin, polysaccharide and other active ingredients, which provide unique material characteristics and medical value, and are expected to be further developed in the future to broaden applications. There are, however, problems in fungal materials, such as production pollution, pathogenicity, service life and future development direction, calling for further study. This paper makes an objective analysis and prospect of fungal materials, hoping to introduce the characteristics of fungal materials comprehensively and help researchers broaden their thinking.

Conclusion and Prospect Fungal materials, with good biocompatibility and no residue after degradation, have great potential to replace fossil-based materials, and their production is not limited by seasons. Particular problems to be solved have been identified as follows. 1) Conditions for fermentation needs to be optimized and suitable fermentation equipment needs to be devised to reduce pollution, as pollution and other problems increase the cost to a large extent. 2) Research on the service life of fungal materials is emperative. 3) The pathogenicity of the selected fungi materials and the possibility of insect colonization in fungi materials to become invasive species needs careful consideration. In a word, there is still a long way to go to use fungal composites on a large scale and the research and development of new fungal materials remain to be attractive.

Significance With the development of sophisticated technologies, novel materials are required for compatibility, lightweight, high strength and temperature resistance. Combined with the large length-to-diameter ratio and high specific surface area of one-dimensional materials, micro-nano inorganic fibers with size effect show great potential for many applications. However, there are some problems including insufficient fineness, poor controllability and continuity in the current methods of preparing micro-nano fibers, such as stretching method, chemical vapor deposition and phase separation. Moreover, the most mature and widely used electrospinning technology has some problems, such as low production efficiency and strict restrictions on spinning solution with high viscosity, which hinder the large-scale industrialization of high-performance inorganic fibers. Recently, electro-blown spinning, based on the coupling effect between electric field force and ejection force of the air stream, has demionstrated capability of contributing to the high yield and high quality of micro-nano fibers. Meanwhile, the airflow can assist in starting, stabilizing, and completing the rotation process of jet. Compared with traditional electrospinning and solution blow spinning technologies, inorganic fibers prepared by electro-blown spinning are characterized by higher yield (dozens to hundreds of times more than electrospinning), small diameter (nanometer and submicron scale) and uniformity.

Progress In order to promote the electro-blown spinning technology and provide theoretical and practical basis for preparing inorganic fiber, this paper reviews the basic researches, including the principle and advanced equipment. The core components are composed of feeding device, spinning die, high-voltage power supply, gas control system and receiving device. For large-scale production, there are many novel designs for spinning die, such as disc multi-nozzle, multi-branch/tip equipment, solution channel surrounded by internal/external double-layer air flow. The influencing factors of fabricating inorganic fibers by this technology are analyzed in detail in terms of the properties of spinning solution, the geometric characteristics of spinneret, the properties of air flow, the spinning voltage and the tip-collector distance, especially the controllable process of industrialization. Moreover, taking Al₂O₃ fiber as an example, the electro-blown spinning technology is compared with solution-blown spinning and conventional electrospinning technology from fiber morphology, pore size of membrane and production efficiency. The advantages and drawbacks of electro-blown spinning technology are discussed and clarified. In addition, the applications of electro-blown spinning inorganic fibers are presented, which concentrates on the fields of dye adsorption and degradation, biomedicine, energy, catalysis and industrial manufacturing.

Conclusion and Prospect It has been demonstrated that the superimposed airflow and electrostatic effect, with a double drafting force makes the electro-blown spinning technology achieve certain breakthroughs in the pursuit of both high yield and high quality of micro-nano inorganic fibers. The technology is suitable for preparing a wide range of ceramic materials and carbon fibers, especially for high-concentration solutions or gels. However, there are still some problems such as insufficient understanding of the jet motion under the dual control of airflow and voltage, poor toughness of produced inorganic fibers and mostly short fibers, and the lack of large-scale electro-blown spinning equipment. Therefore, efforts need to be made in the following aspects in the future. 1) It is crucial to improve the quality of inorganic fiber while ensuring the yield. The laws of jet motion and synergistic control methods under the dual control of airflow/voltage need to be clarified through the establishment of mathematical models and simulation. 2) It is necessary to diversify the structure/function of inorganic fibers. The first is to develop macro/micro special structure inorganic fibers, while the second is to play the advantages of electro-blown spinning technology easily combined with functional materials. 3) It is also necessary to strengthen the development and application of the porous and lightweight inorganic fibers and the ultrafine inorganic yarn.

Significance The diabetic foot is a serious chronic complications in diabetic patients and is characterized by high rates of disability, death, and recurrence. 50% of diabetic foot ulcers and amputations can be avoided through early screening, but only 15.7% of diabetic patients are screened regularly. Studies have shown that monitoring the skin temperature of diabetic patients' feet helps to detect foot abnormalities, and reduce the risk of primary and secondary diabetic foot. Currently, smart footwear for monitoring foot temperature in the diabetic foot has developed, such as Siren Diabetic Socks and SmartSox Socks. However, the willingness of patients for wearing diabetic footwear is low, and medical professionals suggest that there is still a lack of strong evidence for the diagnostic value of such products. Therefore, a comprehensive and scientific analysis of smart footwear for monitoring temperature in the diabetic foot can help improve the systematic understanding of these products among diabetic patients and related researchers, increase the popularity and usage rate, and provide theoretical references for future research.

Progress In order to systematically and objectively understand the mechanism and product efficacy of smart footwear for monitoring foot temperature, the differences in plantar temperature characteristics between different types of diabetic patients and healthy people were compared. Thermograms from the healthy people showed a symmetrical butterfly pattern with the medial arches showing the highest temperatures, while in diabetics, due to inflammation caused by neuropathy, abnormal thermoregulation, and local ischemia caused by peripheral arterial disease, the foot temperature is often higher than that of healthy feet, and the distribution is irregular, with higher temperatures in areas at high risk of ulceration. In order to fully extract the predictive value of temperature, there mainly exist three types of index extraction methods, i.e., thermal symmetry of foot, in dependent limb regional temperature difference, and temperature stress analysis. A 2.2 ℃ difference between contralateral spots is the most widely used as the predictive threshold of diabetic foot disease, and the predictive sensitivity and specificity are often improved by continuous duration-assisted analysis. Recently, smart footwear targeting foot temperature monitoring has been developed. The Optical-Fiber-Based Smart Sock has the advantages of multi-index monitoring, comfortable and reusable. However, there are still differences in the number of temperature sensors and monitoring areas between products. The main monitoring areas are heel, medial midfoot, first metatarsal head, fifth metatarsal head, and first toe.

Conclusion and Prospect The effectiveness of using temperature monitoring to prevent diabetic foot has been unanimously recognized by researchers. It is clinically meaningful to use the temperature difference of 2.2 ℃ between contralateral spots as the prediction threshold for diabetic foot. Nontheless, the individual baseline temperature differences should be taken into consideration, assisted with other indicators such as the duration of temperature difference and pressure, so as to improve the predictive sensitivity and specificity of smart footwear. In the future, the risk level can be identified based on the foot temperature values and distribution patterns of diabetic patients under different activity intensities based on big data, and other indicators such as pressure, shear stress, toe range of motion, humidity, pH, and sweat-based glucose level can be studied in depth to predict the potential value of diabetic foot risk, explore the relationship between the indicators, and dissect the diabetic foot development risk mechanism together with skin temperature. In addition, machine learning can be used to optimize early warning algorithms, automatically calculating and updating the typical foot temperature pattern individualized. Finally, the overall system of shoes and socks needs to be comprehensively explored regarding the care and prevention of diabetic foot.