Measuring Fiber Orientation in Nonwoven Fabrics by Laser Scattering Method Part Ⅱ: Algorithm and Verification

The algorithm for evaluation of fiber orientation distribution function (ODF) by laser scattering method based on 2 - dimentional model of fiber arrangement and the method of determining diffuse scattering intensity are presented. The fiber ODFs of nonwoven samples measured by the computer-program-controlled laser scattering intensity testing system are compared with that of the data obtained by microprojector method. The results show that the algorithm is feasible for assessing the fiber ODFs of nonwoven fabrics manufactured by different processing methods.     

Relationship between Light Scattering Intensity and Basis Weight of Non-Woven Fabrics

The relationship between light scattering intensity and basis weight of nonwoven fabrics is studied by using the theory of electromagnetic wave propagation and scatter-ing in random media.The theoretical analysis shows that the backscattering intensity of nonwoven fabric is closely related to its basis weight,and 2 series nonwoven samples manufactured by spun-bonded and thermal-bounded processing methods are tested for checking the theoretical expression.The study shows that the scattering intensity increases with increasing basis weight of nonwoven fabrics in exponential equation,and theoretical expression is consistent with the experimental data.     

INVESTIGATION OF THE CHARACTERISTICS OF DYNAMIC HEAT AND MOISTURE TRANSMISSIONS THROUGH FABRICS

In this paper, the dynamic heat and moisture transmissions through fabrics are investigated, and their interaction manner is discussed. The essentials of the apparatus developed for measuring the amount of heat flow through fabrics during the whole period of simulated sweating action is reported. The registered heat flow flux in a continuous curve form covering the complete dry-wet-dry cycle of the sample is presented. Interpretation of the feature of the curve and indexes for characterizing the wearing comfort property of fabrics are suggested.     

Thermal Protective Performance of Heat and Flame Resistant Fabrics in Different Radiant and Convective Heat Exposures

The thermal protective performance （TPP） is important for heat and flame resistant fabrics. In this study, fabrics which are made of flame resistant cotton, Nomex, polybenzimidazole （PBI）, polysulfonamide （PSA）, kermel, and blend of kermei with rayon fiber are investigated on high intensity of different radiant and convective heat source. The mechanism of heat transfer in different situations is discussed. It is identified that exposed candition has an important effect on thermal protective performance. TPP rating increases with the increasing percentage of convective heat.     

Analysis of stimulated Brillouin scattering in multi-mode fiber by numerical solution

Stimulated Brillouin scattering in optical fibers is described by a theoretical model and numerical analysis. The results showed that, for an optical fiber pumped by a laser beam with ns-order-pulse width and kW-order peak-power, SBS reflectivity tends to saturate when the fiber length exceeds a limit, named “effective fiber length“. Using small core-diameter and long enough fiber, the SBS reflectivity level could be raised but is limited by optical damage of the entrance surface of the fiber. Therefore, just a small dynamic range can be obtained.     

Gray Synthetic Evaluation on Moisture Comfort of Sportswear Fabrics under the Condition of Heavy Sweating

Moisture and water transfer under the condition of heavy sweating are analyzed. Four different experiments are made to test moisture resistance, water-keep, wicking effect and drying ability of samples. Then gray analysis method is introduced to evaluate the comprehensive comfort of these fabrics. Result shows chemical fiber with high moisture transfer performance has advantage in water transfer and diffusion, which is suitable for human under the condition of heavy sweating. Though natural fiber can absorb moisture well, it cannot transfer fluid sweat. Therefore natural fiber fabrics such as cotton, wool are unsuitable to make functional sportswear.     

Factors Influencing Anti-ultraviolet Performance of Undyed-woven Fabrics

Main factors influencing anti-ultraviolet performance of woven fabrics are investigated. By means of detailed arrangement of sample design, sample making, testing and analyzing, it shows that fiber materials, fabric compactness, fabric weave and yarn type are the four important factors influencing anti-UV performance of woven fabric, but with different effects. Among them fiber material is the most important factor. For the common fiber materials used, it shows that the anti-UV performance of polyester is comparatively better than others. Once fiber material is determined, fabric with medium float weave and high compactness can offer a good anti-UV performance. The anti-UV performance of fabric with ＂anti-UV＂ filament yarn is better than that with ＂anti-UV＂ staple yarn. The anti-UV property of fabrics with untwisted filament yams is better than that with twist counterparts.     

Measurement of the Average Molecular Weight of Cotton Cellulose Crosslinked by a Polycarboxylic Acid at Different pH Using Multiple Angle Light Scattering Photometer in a DMAc/LiCl Solvent System

Durable press finishing of cotton fabrics with polycarboxylic acid increases fabric wrinkle-resistance at the expense of its mechanical strength. Severe tensile strength loss is the major disadvantage for wrinkle resistant cotton fabrics. Tensile strength loss of cotton fabric crosslinked by a polycarboxylic acid can be attributed to depolymerization and crosslink of cellulose molecules. Measurement of the molecular weight of cotton fabric before and after crosslinked by polycarboxylic acids can offer a possibility of direct understanding of the depolymerization. In this research, a multiple angle laser light scattering photometer was used to determine the absolute molecular weight of cotton fabric treated with BTCA at different pH and then hydrolyzed with 0.5 M NaOH solution at 50℃ for 144 h. The results indicate that average molecular weights of cotton fabric treated with polycarboxylic acids at different pH are almost the same.     

RESEARCH ON THE STRUCTURE AND THE PROPERTY OF THE HYGROSCOPIC AND PERMEABLE FABRIC FOR SPORTSWEAR

Two structure models for knitting fabric are set up according to the wet-heat transmission principle of the fabric. Four kinds of knitted fabrics for sportswear are designed and produced. The wet-heat property of these fabrics is researched.     

Comparison of Low Stress Mechanical Properties of Light Weight Wool and Wool Blend Fabrics using the KES-F and FAST Instruments

This study compares the test results of the FAST (Fabric Assurance by Simple Testing) with those of the KES - F (Kawabata Evaluation Systems for Fabrics) for a range of nineteen light weight wool and wool blend fabrics in terms of the low - stress mechanical properties of bending, shear, and tensile deformation. It is found that there are very significant correlations between the corresponding parameters for extensibility and shear rigidity obtained from the test results of the two systems. The correlation between the values of bending rigidity obtained from the two systems is only moderate. Furthermore, for the fabrics tested in this study, the values of bending rigidity, shear rigidity, and extensibility measured using the KES - F instruments are higher than those of the corresponding parameters measured using the FAST instruments. The linear regression equation is given for each pair of corresponding parameter.     

Measuring Fiber Orientation in Nonwoven Fabrics by Laser Scattering Method Part II: Algorithm and Verification

The algorithm for evaluation of fiber orientation distribution function (ODF) by laser scattering method based on 2 - dimentional model of fiber arrangement and the method of determining diffuse scattering intensity are presented. The fiber ODFs of nonwoven samples measured by the computer- program-centrolled laser scattering intensity testing system are compared with that of the data obtained by microprojector method The results show that the algorithm is feasible for assessig the fiber ODFs of nonwoven fabrics manufactured by different processing methods.     

基于激光散射强度测量非织造布面密度的实验研究

应用光技术测量原理研究了非织造布的激光散射强度与面密度的关系,并应用计算机程序控制非织造布激光散射强度测定系统测定和分析了3种加工方法的非织造布试样。结果表明:非织造布面密度与激光散射强度之间存在十分密切的关系,这里所述的方法具有无放射性和易于采用计算机测量的优点,可用于薄型非织造布面密度的测量。     

基于PCS的纳米颗粒粒度测量系统设计

引入不同孔径的光纤传输激光和散射光子,不同孔径的Y形光纤传输入射光和散射光,采用光子相关光谱法（PCS）设计了纳米颗粒测量系统.讨论了光纤芯径、显微物镜的数值孔径、温度和散射角度对测量结果的影响.实验结果表明,温度在13~22 ℃超净间中,该系统能准确地测量纳米颗粒粒度.     

Strength Distribution Analysis of Typical Staple Fibers

IntroductionThe mechanical properties of yarns are deter mined bytheir constituent fibers.Consequently,the strength offibers is an i mportant property in deter mining the finalquality of all textile products.Generally,it is al ways truethat the higher the strength of fibers,the higher thestrength of yarns and fabrics.However,because of the variation of fiber strength,the fibers within a yarn will not break at the same ti meunder a tensile load.In fact,break will take place at theweakest fiber…     

短纤维强力的概率分布分析

纤维强力对于纱线乃至织物来说都是一个重要的性能，而纤维的强力有一定分布。这里对羊毛、绢丝、棉、亚麻、腈纶、涤纶、芳纶、玻璃纤维、碳纤维等9种纤维的强力进行了测试和统计分布拟合。发现棉、腈纶、涤纶、芳纶和碳纤维的强力严格符合二参数的Weibull分布，而羊毛、绢丝的强力则符合三参数的Weibull分布，而亚麻的强力用两种     

用于裂隙光源的侧面发光塑料光纤散射点设计

设计一种侧面发光塑料光纤表面正四棱锥形微结构散射点，使侧面发光塑料光纤可用作裂隙灯显微镜的裂隙光源，以减小裂隙光源的体积.采用光学仿真软件分析光纤上表面(有散射点)和光纤下表面(无散射点)的散射率，当塑料光纤直径为1 mm时，得到优化后的正四棱锥散射点的底边宽度和深度均为80μm.仿真结果表明，光纤下表面散射光的光束发散角在垂直于光纤方向约为40°,在平行于光纤方向约为110°,经过焦距为50 mm的投射镜会聚后的光带宽度约为0.3 mm,可以满足裂隙灯显微镜的要求.     

掺镱光纤激光器时域特性的研究

利用光纤的非线性效应－受激布里渊散射（SBS）和二色镜的选频利用,以国产的激光二极管作泵浦源,在掺镱光纤激光器中得到了稳定的自调Q光脉冲输出,脉冲重复频率为29．4MHz,脉冲光宽度约为2ns。     

混杂纤维格栅编织物混凝土梁弯曲强度试验

对碳/玻璃混杂纤维格栅织物增强混凝土复合材料进行三点弯曲试验,绘出了它们的典型荷载挠度曲线,实验结果表明,碳/玻璃混杂纤维格栅织物增强混凝土的效果是很明显的.最后展望了该材料在建筑结构中的发展前景.     

基于光频域反射技术的表面粘贴分布式光纤传感器应变传递特性分析与试验

分布式光纤传感器由多层结构组成,用于测量土木工程构筑物表面变形时,光纤与结构基体间存在一个应变传递过程。为了揭示表面粘贴分布式光纤传感器应变传递特性规律,结合经典的剪滞理论,分析光纤在不同粘贴长度和中间层参数下,低应变传递系数区段的范围与变化。通过室内试验,在PVC管表面紧邻并行粘贴两条光纤,采用基于光频域反射(optical frequency domain reflectometer,OFDR)的分布式光纤感测技术测量光纤在管中部受不同集中荷载下的应变,得到应变传递系数分布及变化。结果表明:在不同荷载下,OFDR实测光纤应变传递系数的分布规律具有一致性,符合理论分析,研究成果对分布式光纤传感器应用于结构表面变形的检测与监测工作具有一定的指导意义。