Search

NIMA (never in mitosis, gene A)-related kinase-6 (NEK6) a cell cycle regulatory gene was found to regulate cardiac hypertrophy. However, it’s role in diabetic cardiomyopathy (DCM) have not been fully elucidated. This research was designed to illustrate the effect of NEK6 involved in DCM. Here we used a streptozotocin (STZ) induced mice diabetic cardiomyopathy model and NEK6 knockout mice to explore the role and mechanism of NEK6 on DCM. NEK6 knockout mice and wild type littermates were subjected to STZ injection (50mg/kg/d for five constitute days) to induce DCM model. As a result, 4 months after final STZ injection, DCM mice revealed cardiac hypertrophy, fibrosis and systolic and diastolic dysfunction. NEK6 deficiency caused deteriorated cardiac hypertrophy, fibrosis as well as cardiac dysfunction. Moreover, we observed serve inflammation and oxidative stress in NEK6 deficiency mice heart under DCM pathology. We used an adenovirus to overexpress NEK6 in neonatal rat cardiomyocytes, and found that NEK6 ameliorated high glucose induced inflammation, and oxidative stress. Mechanismly, we found that NEK6 increased phosphorylation of heat shock protein 72 (HSP72) and enhanced the protein level of PGC-1α, NRF2. Co-IP assay experiment confirmed that NEK6 interacted with HSP72. When we silence HSP72 the anti-inflammation and anti-oxidative stress effects of NEK6 were blurred. In summary, NEK6 could protect diabetic induced cardiomyopathy via interacting with HSP72 and promoting the HSP72/PGC-1α/NRF2 signaling.

Fabrics with weaves of low interlacing density and smooth yarns such as continuous cuprammonium filaments are often susceptible to sewing damage of cracks perpendicular to the sewing line, seriously influencing the aesthetics of the finished garment. To understand how the important factors such as yarn modulus, yarn bending stiffness, sewing needle radius, yarn-on yarn-friction, fabric counts and fabric weaves act on the crack length of such a fabric, a micromechanical model is proposed, and the experimental results are compared with the theoretical prediction. Single yarn pull-out tests and single yarn axial compression tests are performed to estimate yarn-on-yarn friction and yarn bending stiffness, respectively. The model indicates that the sewing crack length is positively proportional to the yarn tensile modulus, yarn bending stiffness and the needle radius and is negatively proportional to the fabric count and the inter-yarn friction. The model predicted crack lengths are within the range of the experimental results in warp direction while the predicted value is substantially larger than the observed crack lengths in weft direction due to the high compressibility of the weft yarn, which decreased yarn tension, bending stiffness and increased yarn cover power. For a given fabric, increasing yarn-on-yarn friction and raising yarn compressibility is an effective way to control the crack lengths.

The interfacial structure and binding forces of polytrimethylene terephthalate/polyethylene terephthalate filament were investigated through the methods of Carbon-13 nuclear magnetic resonance (13C-NMR), differential scanning calorimeter (DSC), scanning electron microscopy (SEM) and optical microscopy. When two molten polymers met during the spinning process, an interface layer between the PTT and PET components formed and played an important role in binding the two components together. When the blending time was sufficient, an ester-interchange reaction took place with the generation of the copolymer. The PET recrystallisation was observed in the DSC curve under the influence of entangled PTT molecular chains. The morphology of the cross-section and side view proved that the linear boundary line was short and weaker in binding without a chemical bond and molecular diffusion. Side-by-side bi-component fiber and split-type fiber was able to be controllably spun by adjusting the spinning parameters.

Electroneurophysiology has been more and more widely used to evaluate the tactile comfort of fabrics. In our previous study, it was found that three different types of subjects exist, namely extraordinary, ordinary, and non-sensitive people, corresponding to their electroneurophysiological responses to fabric-skin contact. In the current study, 19 subjects were recruited, including one extraordinary sensitive, eight ordinary sensitive and 10 non-sensitive subjects who were tested with a smooth cotton fabric and a rough polyester fabric in a fabric-skin dynamic contact experiment. Electromyography, electroencephalography, and electrocardiography signals of the human body, paired with subjective evaluation were carried out. The results show that the rough polyester fabric, compared with the smooth cotton fabric, tended to cause higher mean amplitude and larger waveform area of the myoelectric potential, reduced energy percentage of α wave, improved pneumogastric nerve activity and heart rate variability of the ordinary sensitive subjects, indicating more discomfort in fabric-skin dynamic contact. However, for the non-sensitive subjects, no consistent pattern could be observed in all of the above indicators. Therefore, the ordinary sensitive subjects are more suitable in clothing tactile comfort evaluation using electroneurophysiological measurements. In addition, it was found that ordinary sensitive subjects are predominantly females while non-sensitive subjects are most likely males.

Particulate matter (PM) with a diameter of 0.3 µm is inhalable and brings great threats to human health. Traditional meltblown nonwovens used for air filtration need to be treated by high voltage corona charging, which has the problem of electrostatic dissipation and thus reduces the filtration efficiency. In this work, a kind of composite air-filter with high efficiency and low resistance was fabricated by alternating lamination of ultrathin electronspun nano-layer and melt-blown layer without corona charging treatment. The effects of fiber diameter, pore size, porosity, layer number, and weight on filtration performance were investigated. Meanwhile, the surface hydrophobicity, loading capacity, and storage stability of the composite filter were studied. The results indicate that the filters (18.5 gsm) laminated by 10 layers fiber-webs present excellent filtration efficiency (97.94%), low pressure drop (53.2 Pa), high quality factor (QF 0.073 Pa−1), and high dust holding capacity (9.72 g/m2) for NaCl aerosol particles. Increasing the layers and reducing individual layer weight can significantly improve filtration efficiency and reduce pressure drop of the filter. The filtration efficiency decayed slightly from 97.94% to 96.48% after 80 days storage. The alternate arrangement of ultra-thin nano and melt-blown layers constructed a layer-by-layer interception and collaborative filtering effect in the composite filter, realizing the high filtration efficiency and low resistance without high voltage corona charging. These results provided new insights for the application of nonwoven fabrics in air filtration.

Three-dimensional lithium (Li) hosts have been shown to suppress the growth of Li dendrites for next generation Li metal batteries. Here, we report a cost-effective and scalable approach to produce highly stable Li composite anodes from industrial hemp textile waste. The hemp@Li composite anodes demonstrate stable cycling both in half and full cells.

Intramolecular guanine quadruplexes (G4s) are non-canonical nucleic acid structures formed by four guanine (G)-rich tracts that assemble into a core of stacked planar tetrads. G4-forming DNA sequences are enriched in gene promoters and are implicated in the control of gene expression. Most G4-forming DNA contains more G residues than can simultaneously be incorporated into the core resulting in a variety of different possible G4 structures. Although this kind of structural polymorphism is well recognized in the literature, there remain unanswered questions regarding possible connections between G4 polymorphism and biological function. Here we report a detailed bioinformatic survey of G4 polymorphism in human gene promoter regions. Our analysis is based on identifying G4-containing regions (G4CRs), which we define as stretches of DNA in which every residue can form part of a G4. We found that G4CRs with higher degrees of polymorphism are more tightly clustered near transcription sites and tend to contain G4s with shorter loops and bulges. Furthermore, we found that G4CRs with well-characterized biological functions tended to be longer and more polymorphic than genome-wide averages. These results represent new evidence linking G4 polymorphism to biological function and provide new criteria for identifying biologically relevant G4-forming regions from genomic data.

In this paper, a novel kind of electromagnetic (EM) functional textiles is proposed, which show high-pass characteristics as they interact with EM waves. The periodically conductive woven fabric was designed, fabricated, and measured. Specifically, by means of unit cell model building and EM simulation, the theoretical S21 (transmission coefficient) and S11 (reflection coefficient) curves were obtained. A concrete sample was fabricated through weaving process, and its transmission characteristics were measured in the microwave anechoic chamber. The measured and simulated results were highly consistent, demonstrating the validity of design process. Compared with the aluminum foil paper sample, the S21 values of fabricated sample were a little smaller, and the reason could be attributed to yarn crimp and surface roughness. The EM characteristics of fabricated sample under two different polarization modes were slightly different, which was due to the beating-up tension of weaving process. The work could offer new research ideas, and the related products have potential advantages over rigid plates on the account of textile characteristics.

assa

In this paper, frequency selective fabrics (FSFs) with narrow-band transmission characteristics were proposed. The square-ring FSF was taken as an instance to illustrate the design principle. Based on the existing theoretical basis and by means of software simulation and optimization, the optimum structures with ideal narrow-band band-stop or band-pass characteristics were obtained. Then, the practical specimens were manufactured through a computer-based carving process and measured using the transmission method in an anechoic chamber. Two structural models were respectively simulated using two different algorithms and the results showed very small differences, primarily verifying the effectiveness of the design methods and reasonability of the model simplification. The measured and simulated transmission characteristics of square-ring FSFs were compared and showed a high consistency, which further verified the validation of the design method. The other two kinds of FSFs, namely Jerusalem-shaped and circle/ring hybrid FSFs, were designed and measured, which showed the narrow-band frequency selective characteristics were quite ideal. This indicates that the proposed design method using simulation software may be applied to many different structures and has directive sense in the related product design and development process.

Two kinds of complementary cylindrical frequency selective fabrics (CFSFs) with Jerusalem-shaped units were designed, constructed and analyzed in this paper. The models were built and simplified based on the thickness and equivalent electromagnetic parameters of the base fabrics. Considering the unit number difference of the models and bending directionality, the simulation processes were separately carried out using the waveguide method in HFSS software. Based on the preparation of preliminary planar prototypes and corresponding bending molds, different CFSF samples with the same planar units and varying bending curvature were fabricated, and the transmission characteristics were measured using the transmission method to study the influences of bending effects. The measured transmission characteristics with and without the curved mold were similar, proving the use of the curved mold exerted a negligible effect on the actual measured results of samples. For the two kinds of complementary structures, the measured and simulated S21(transmission coefficient) curves had indistinguishable differences, which justified the validity of the modeling and simulation process. Although the bending direction and curvature affected the S21curves of aperture and patch CFSFs at varying degrees, the transmission characteristics did not show drastic fluctuation and shifting, which could be attributed to the ideal symmetry of Jerusalem-shaped units and good array characteristics.

Scalable manufacturing of yarn-based supercapacitors with high energy density is highly desired for powering wearable electronics and smart textiles. In this paper, we report a novel type of sheath-core polyaniline nanowire array grown on aligned carbon nanofibers/carbon fiber yarn electrode (CFY@CNFs@PANI NWA) based supercapacitors. The carbon fiber yarn can maintain the yarn electrode with high electrical conductivity and mechanical properties. The introduced PANI NWA can further enlarge the specific surface area of the electrode and introduce pseudo-capacitance. The assembled solid-state supercapacitors show high areal specific capacitance of 234 mF/cm2 at a current density of 0.1 mA/cm2, and corresponded energy density of 21.4 μW h/cm2 at power density of 0.52 mW/cm2 in EMIMBF4/PVDF/DMF gel electrolyte. The supercapacitors also exhibit ultrahigh rate capability (68%) and excellent cycle stability (90% after 8000 cycles). We also demonstrated that a 20-cm long supercapacitor can be readily to power up 36 pieces of red LEDs with a logo of “DHU”. The scalable strategy paves a way towards mass production of wearable energy storage devices for smart textiles.

Based on the research work of traditional electromagnetic shielding fabrics and frequency selective surfaces, the novel high-pass woven fabrics were proposed. Two different unit cell models were built and compared, and a series of design samples were further simulated based on the models. Through contrastive analysis and discussion of the simulated results, the validity of model 1 was verified and the influence rules of various parameters were explored. Compared with model 1, model 2 was more precise containing the textile information, like yarn crimp, fabric porosity and thickness, but model 1 could substitute model 2 to predict the transmission characteristics to some extent. The ratio of conductive and dielectric yarns affected the high-pass characteristics greatly, and different from two-dimensional high-pass woven fabrics, one-dimensional high-pass woven fabrics showed distinct polarization selective characteristics. Yarn electromagnetic parameters and fabric parameters could also exert an effect on the S21 curves in different degrees, which could help designers choose materials and determine the fabric parameters effectively. The modelling and simulation work could provide guidance to the development of actual high-pass woven fabrics.

Uniform NiS hierarchical hollow cubes were facilely fabricated by an anion exchange reaction of low-cost Ni formate framework precursor ([CH3NH3][Ni(HCOO)3]) with S2−. The hierarchical hollow structure formed due to the Kirkendall effect and Ostwald ripening. When evaluated as electrode materials for supercapacitors, NiS hierarchical hollow cubes exhibited high specific capacitance (874.5 F g−1 at 1 A g−1) and good cycling stability (retention of 90.2% after 3000 cycles). Moreover, the as-fabricated asymmetric supercapacitor had an enhanced energy density of 34.9 Wh kg−1 at a power density of 387.5 W kg−1.

Electrostatic precipitation is combined with a carbon fabric filter to develop a novel filtration system with high collection efficiency for submicron particles while maintaining a pressure drop as low as 6–56 Pa. The effects of high voltages on the filtration properties of carbon woven fabric filters are investigated by varying the fabric areal density, face velocity, number of fabric layers, and environmental relative humidity (RH). The filtration performance tests show that the corona initiation voltage applied to carbon woven fabric should be higher than 20 kV in ambient condition, and filtration efficiency increases with the increasing of fabric areal density and supplied voltage. As the face velocity increases from 2 m/min to 4 m/min, the filtration efficiency at 30 and 40 kV decreases 13%. As the face velocity increases from 4 to 8 m/min, the filtration efficiency decreases much less. The filtration efficiency is not significantly influenced by the number of fabric layers but can be increased dramatically with the increasing of RH. The maximum filtration efficiency reaches 99.8% for PM 1.0 at high RH. Meanwhile, the corona inception voltage decreases to 10 kV as the RH increased from 40% to 95%.

SnSb nanoparticles are dispersed in carbon nanofibers by electrospinning technology and different SnSb precursors, including Sn0.92Sb0.08O2.04 nanoparticles, Sn(CH3COO)2/Sb(CH3COO)3, and SnCl4·5H2O/SbCl3, are used to tune the morphology of the resultant SnSb/C nanofibers. Porous SnSb/C nanofibers are formed during carbonization Sn0.92Sb0.08O2.04 nanoparticles and Sn(CH3COO)2/Sb(CH3COO)3 are used as precursors of SnSb, while solid nanofibers are observed with SnCl4·5H2O/SbCl3 as the precursor indicating the formation mechanism is closely related to the properties of SnSb precursors. Excellent cycling preference (99% capacity retention after 200 cycles) and high coulombic efficiency (above 99% after 10 cycles) are obtained for the SnSb/C nanofibers using Sn0.92Sb0.08O2.04 as precursor, due to its high surface area and stable SnSb/C structure. It is demonstrated that the uniquely designed composite nanofiber structure with excellent lithium storage performance can be realized simply by selecting precursors with appropriate dissolution and decomposition properties.

Metal–organic framework (MOFs)-derived metal oxides with diverse morphologies and microporous structures have shown potential applications in heterogeneous catalysis. In this study, two types of porous Co3O4 catalysts, Co3O4–MA and Co3O4–DMA (MA = methylamine and DMA = dimethylamine), were successfully synthesized via a one-step pyrolysis of Co-based metal-formate frameworks, [Amine][Co(HCOO)3] (Amine = methylamine, dimethylamine), in air. The obtained porous Co3O4 catalysts were systematically characterized by XRD, SEM, TEM, XPS, H2-TPR, and N2 adsorption–desorption analysis. The results show that the obtained porous Co3O4 catalysts are composed of nanoparticles and inherit the morphology from the precursor [Amine][Co(HCOO)3]. Co3O4–MA and Co3O4–DMA exhibit an excellent catalytic activity for CO oxidation, with both of them reaching a 100% CO conversion at 170 °C.

Mn3O4 hollow microcubes and solid nanospheres were selectively fabricated from a metal formate framework ([CH3NH3][Mn(HCOO)3]) by employing the ion exchange reaction in alkaline solution under different hydrothermal conditions. The relationships between Mn3O4 morphology and reaction molar ratio and reaction time were investigated. When used as the electrode materials for supercapacitors, Mn3O4 hollow microcubes and solid nanospheres had specific capacitances of 176 and 150 F g−1 respectively at a current density of 0.3 A g−1 in 1 M Na2SO4. The specific capacitance retentions of the Mn3O4 hollow microcubes and solid nanospheres were 95% and 86% respectively after 8000 charge–discharge cycles at a current density of 2 A g−1. Electrochemical results show that the Mn3O4 hollow microcubes and solid nanospheres exhibit acceptable specific capacitance and excellent cycling stability.

In order to improve the cycling stability of SnSb/C nanofiber anodes for Li-ion batteries, the deep cryogenic treatment was firstly used to modify the morphology structure of SnSb/C nanofibers. Three different processing schedules were employed to treat SnSb/C precursor nanofibers including direct carbonization, deep cryogenic treatment & carbonization, and carbonization & deep cryogenic treatment. The morphology structure, especially the morphology rebuilding mechanism has been evaluated after being treated by these three schedules. The decreased-porous and increased-porous SnSb/C nanofibers were rebuilt because the increased carbon trapped in pores to close some pores and induced more CO2 evolution to create more pores, respectively. The SnSb/C nanofiber anodes with more pores and larger surface area exhibited improved cycling stability and coulombic efficiency. The deep cryogenic treatment was successfully used to modify the morphologies and properties of nanofibers, it provided a new way to improve the electrochemical performance of nanofiber anodes.

Polyacrylonitrile-based carbon fibers are cryogenically conditioned both through a low cooling rate and a quench rate to explore the effects of cryogenic treatments on properties and micro-structures of carbon fibers. The internal structure, tensile properties and surface morphologies of the fiber are investigated. Increase in crystallinity and tighter packing of molecules of the fiber after the cryogenic treatments are observed regardless the cooling rate. After slow cooling cryogenic treatment, the inter-planar distance increases in the fiber axial direction and decreases in the fiber radial direction, resulting in 3% shrinkage of fiber diameter and extension in fiber axial direction. Scanning electron microscopy and atomic force microscopy analysis show slightly wider and deeper rill-like folds and 41% roughness increase for the fiber surfaces, leading to an increase in interfacial shear strength between the fiber and epoxy by 30.2%. In contrast, after sharp cooling cryogenic treatment, no obvious change is detected in inter-planar distance, fiber diameter, surface morphology and interfacial shear strength with epoxy. The bimodal additive Weibull distributions of tensile strengths for the cryogenic treated fibers show an increase of the bimodality parameter α and a decrease in scale parameter σ indicating higher probability of extrinsic defects but no significant mechanical degradation of the fiber after cryogenic treatments.

Current research was carried out on hydrophilic wool fibers at three different humidity conditions through atmospheric pressure plasma jet (APPJ). Samples were taken to evaluate surface microscopic morphology, surface roughness, directional friction effect (DFE), and surface chemical composition. The scanning electron microscope (SEM) and fiber friction coefficient test (FFT) results show that wetting pretreatment has significant effect on surface etching and DFE, but very limited effect on surface roughness. Allworden reaction and X-ray photoelectron spectroscopy (XPS) results reveal that extra moisture changes C, O, N, S contents and their related characteristic functional groups, therefore increases etching degree on wool fiber surface scales. It was concluded that APPJ treatment is effective in processing wool fiber with high moisture contents.

Cellulose acetate was dissolved in trifluoroacetic acid and electrospun onto polypropylene non-woven material. An upstream layer of polypropylene non-woven material was added to form a three-layered polypropylene/cellulose acetate/polypropylene filter. The thickness of the electrospun cellulose acetate layer was varied by changing the electrospinning time. The fabricated filter was then characterized. Cellulose acetate nanofibers were also electrospun onto an aluminum foil collector with the aim of studying the changes in fiber properties when they are electrospun onto the polypropylene non-woven material. The results obtained in this research work indicated that the layer of nanofibers electrospun onto polypropylene non-woven material increased the filtration efficiency of polypropylene non-woven material from 50.23% to 91.29%, but the quality factor reduced by 29.1%. When the cellulose acetate deposition time was increased from 3 h to 6 h, the filtration efficiency further increased to 98.26% and the quality factor increased by 0.6%. A comparison between cellulose acetate nanofibers electrospun using an aluminum foil as the collector and those electrospun directly onto the polypropylene non-woven material indicated that cellulose acetate fibers electrospun onto polypropylene non-woven material had poorer fiber quality properties.

Poly vinylidene fluoride:poly methyl methacrylate:cellulose acetate (CA) at ratios of 100:0:0, 90:10:0, 90:5:5 and 90:0:10 respectively, were successfully electrospun. These membranes were mixed to form a 12 wt% solution prepared with volume ratio 7:3 of DMAc:acetone solvents. These membranes were then analyzed using differential scanning calorimetry, scanning electron microscopy, FTIR, WAXD, pore size, porosity% and electrolyte uptake (EU)%. It was observed that the best absorption results were obtained in the presence of CA. The electrospun membrane at ratio of 90:0:10 was observed with the highest porosity of 99.1 % and EU at 323 %. It also had a 43.6 % crystallinity and a 162 °C melting temperature. It was then concluded that addition of CA improved the separator properties.

In this work the effect of atmospheric plasma treatment on carbon fiber has been studied. The carbon fibers were treated for 1, 3 and 5 min with a He/O2 dielectric barrier discharge atmospheric pressure plasma. The fiber surface morphology, surface chemical composition and interfacial shear strength between the carbon fiber and epoxy resin were investigated using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and the single fiber composite fragmentation test. Compared to untreated carbon fibers, the plasma treated fiber surfaces exhibited surface morphological and surface composition changes. The fiber surfaces were found to be roughened, the oxygen content on the fiber surfaces increased, and the interfacial shear strength (IFSS) improved after the atmospheric pressure plasma treatment. The fiber strength showed no significant changes after the plasma treatment.

Both air/He and air/O 2/He atmospheric plasma treatments are applied to desize PVA on cotton, then PDR (percent desizing ratio) and tensile strengths of cotton fabrics and single yams are measured. XPS and SEM are used to analyze the effects of atmospheric pressure plasma treatments on PVA. These treatments can both remove some PVA sizing and significantly improve PDR by washing, especially by cold water washing. The tensile strengths of cotton fabrics treated with atmospheric pressure plasma are the same as for the unsized fabric. XPS analysis of the plasma treated PVA films reveals surface chemical changes such as chain scission and formation of polar groups, which promote the solubility of PVA in cold water. Air/O2/He plasma is more effective than air/He plasma on PVA desizing.

In order to investigate the effect of atmospheric pressure plasmas on adhesion between aramid fibers and epoxy, aramid fibers were treated with atmospheric pressure helium/air for 15, 30 and 60 s on a capacitively-coupled device at a frequency of 5.0 kHz and He outlet pressure of 3.43 kPa. SEM analysis at 10 000× magnification showed no significant surface morphological change resulted from the plasma treatments. XPS analysis showed a decrease in carbon content and an increase in oxygen content. Deconvolution analysis of C1s, N1s and O1s peaks showed an increase in surface hydroxyl groups that can interact with epoxy resin. The microbond test showed that the plasma treatment for 60 s increased interfacial shear strength by 109% over that of the control (untreated). The atmospheric pressure plasma increased single fiber tensile strength by 16-26%.

The aging effects of atmospheric plasma treatments on UHMPE fibers are studied. UHMPE fibers are treated for 0.5 and 1 min with He/O2/air gas and for 2 and 4 min with He/air gas by atmospheric pressure plasma on a capacitively coupled device at a frequency of 5 kHz. The samples are tested for fiber/epoxy interfacial shear strength at time intervals of 0, 3, 15 and 30 days after initial plasma treatment. Scanning electron microscopy shows micro-cracks on each set of treated fibers, which is not affected by aging over the 30 day study. Interfacial shear strengths (IFSS) for plasma-treated fibers are 2–3 times as high as that of the control. The IFSS for the plasma treated fibers remains constant up to 15 days and then decreases afterwards. XPS Analysis shows a slight increase in atomic concentration of oxygen and nitrogen for each plasma-treated sample. For the He/O2/air plasma-treated samples, XPS analysis shows an observable increase in C–OH bonds, C=O bonds and COOH bonds, while for the He/air plasma-tre...

For fibers with irregular cross sections such as ultrahigh modulus polyethylene (UHMPE) fibers and ribbon-like carbon fibers, the original shear lag model would not provide accurate calculations for interfacial shear stress because it assumes a circular fiber cross section. In this study, a modified shear lag model is proposed to calculate the interfacial shear stress that reflects the change of fiber cross-sectional shape. Microbond test on a UHMPE fiber/epoxy system was used for verification of the model. The difference between the interfacial shear strength (IFSS) calculated using the modified model and that using the original model assuming an equivalent fiber diameter was found to be as high as 15% and it linearly increased as the irregularity of the cross-sectional shape increased. When the irregularity constant exceeds 1.12, the error in IFSS involved in using the original shear lag model and an equivalent fiber diameter is greater than 10%.

In this study, both air-oxygen-helium and air-helium atmospheric pressure plasma treatments were employed to desize PVA on a rayon (viscose) fabric. Both the plasma treatments were able to remove some of the PVA on the rayon fabric and increase PVA solubility in cold water, resulting in a higher weight loss in cold washing. The effect of the atmospheric pressure plasmas became greater as the treatment time increased. Plasma treatment followed by one cold and one hot washing had the same effect as the conventional chemical treatments followed by two cycles of cold and hot washing. The atmospheric plasma treatment did not have negative effect on rayon fabric tensile strength.

Ultrahigh modulus polyethylene fibers were treated with atmospheric pressure helium + oxygen plasma in a capacitively coupled device at a frequency of 7.5 kHz. The fibers were treated for 0, 0.5, 1, 1.5, and 2 min. The surfaces of the fibers treated with He + O2 plasma were etched and micro-cracks were formed. XPS analysis showed a 65ndash213% increase in oxygen content on the surfaces of all plasma-treated fibers, except for the 1.5 min group. An increase in the concentration of C—O and the appearance of C=O bonds on the surfaces of plasma-treated fibers were observed. In the micro-bond test, He + O2 plasma-treated groups had a 65–104% increase in interfacial shear strength over that of the control. The tensile strength of the fibers was either unchanged or decreased by 10–13% by the plasma treatments.

Ultrahigh-modulus polyethylene fibers were treated with atmospheric pressure He plasma on a capacitively coupled device at a frequency of 7.5 kHz and a He partial vapor pressure of 3.43 × 103 Pa. The fibers were treated for 0, 1, and 2 min. Microscopic analysis showed that the surfaces of the fibers treated with He plasma were etched and that the 2-min He plasma-treated group had rougher surfaces than the 1-min He plasma-treated group. XPS analysis showed a 200% increase in the oxygen content and a 200% increase in the concentration of C—O bonds (from 11.4% to 31%) and the appearance of C=O bonds (from 0% to 7.6%) on the surface of plasma-treated fibers for the 2-min He plasma-treated group. In the microbond test, the 2-min He plasma-treated group had a 100% increase of interfacial shear strength over that of the control group, while the 1-min He plasma-treated group did not show a significant difference from the control group. The 2-min He plasma-treated group also showed a 14% higher single-fiber tensil...