Biodegradability of cellulose fabrics

Biodegradability of cellulose fabrics was evaluated by use of a soil burial test, an activated sewage sludge test, and an enzyme hydrolysis. Surface changes after biodegradation were observed by optical microscopy. From X‐ray diffraction analysis (XRD), changes in the crystallinities and the internal structures as a result of degradation were also investigated. It was shown that biodegradability decreased in the following order: rayon > cotton ? acetate. Rayon fibers, which have a low crystallinity and a low degree of orientation, showed the highest biodegradability in most cases. However, in spite of its low crystallinity, acetate fibers exhibited very low biodegradability, probably because of the presence of hydrophobic groups in its structure. On the other hand, linen showed an inconsistent behavior in that it had the highest biodegradability in the soil burial test, but a lower biodegradability than that of cotton in the activated sewage sludge test. XRD analysis revealed that there was a slight increase in the crystallinity of linen, cotton, and rayon fabrics at the initial stage, but a continuous decrease thereafter. From the correlation analysis, it was revealed that the biodegradability of cellulose fabrics was closely related to the moisture regain of the fibers, which reflects the hydrophilicity and internal structure of the fibers at the same time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 248–253, 2004     

快速虚顶点光子映射的焦散绘制

目的 模拟绘制焦散效果是真实感图形绘制的重要组成部分。利用可编程GPU硬件,基于图像的光子映射方法绘制速度快,但由于使用了近似采样和计算,会产生失真。为了克服这一现象,针对理想的镜面反射、折射体,提出一种快速绘制焦散效果的方法（VOBPBT）。方法 该方法首次定义了光子路径映射图的概念,并提出通过基于虚顶点光子映射的光子束跟踪来准确构建光子路径映射图的方法;此外,方法也创新性地提出利用光子路径映射图来查找焦散三角形,创建焦散映射图的方法。结果 实验结果表明,本文绘制结果真实,可以处理多次递归反射、折射,能够绘制连贯的高频焦散效果,同时可以达到交互的绘制性能。结论 本文VOBPBT方法在可交互计算机仿真、计算机游戏、虚拟漫游等应用领域具有一定的实用价值。     

Time optimization of ultraviolet–ozone pretreatment for improving wool fabrics properties

Wool fabrics were exposed to ultraviolet (UV)–ozone treatment for different periods. After exposure, the fabrics were analyzed by Fourior transform infrared spectroscopy (FTIR). Also, the crystallinity and amorphousity regions were followed by an X‐ray diffraction technique. The results were correlated by mechanical properties measurements. After a certain period of exposure, the dyeability and printability were improved because these abilities are strongly related to the percentage ratio of crystallinity regions to amorphousity regions in wool fabrics. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1469–1476, 2002     

X射线荧光光谱法测定连铸保护渣的化学成分

根据连铸保护渣成分及试样特点,对试样预处理、试样熔融条件、熔制程序及干扰校正等进行试验研究,运用X射线荧光光谱法测定连铸保护渣中主要化学成分的含量。测定结果显示,各成分校准曲线相关系数大于0.999,相对标准偏差小于0.5%,与化学法对照结果无显著差异。     

三维温度梯度场中本征声线轨迹的求取

为了降低声波在温度梯度场中的折射现象对声学CT法温度场重建精度的影响,研究了温度梯度场中声波的真实传播路径,即本征声线轨迹,提出了一种三维本征声线出射角确定法.利用正三棱锥前向展开法,在单峰、双峰模型温度场中进行了三维本征声线追踪.结果表明,三维温度梯度场中的声线轨迹有明显弯曲,该三维本征声线轨迹求取法可用于复杂三维温度场中实际声线轨迹的确定,并有望应用于三维温度场声学CT重建系统中.     

基于手势的交互式三维场景并行光线跟踪绘制研究

利用光线跟踪可以绘制出高质量的真实感场景画面,但计算量很大,难以实现实时交互式绘制.为此,三维真实感场景的实时交互式绘制往往需要用到集群,但集群的绘制速度是由绘制速度最慢的节点决定的,如果节点之间的任务没有被划分均匀,集群的绘制效率就会下降.为了满足实时交互式绘制的要求、提高集群的绘制效率,设计了在粗粒度和细粒度两个层次上同时实现并行计算的集群绘制系统,并针对集群的负载均衡问题提出了基于像素递归深度的负载均衡方法.该方法首先统计出每个像素的递归深度从而得到整个场景的递归深度图,然后对上一帧按递归深度进行均衡划分.根据连续两帧所对应的场景具有的时空相关性,上一帧的划分结果可作为下一帧划分的依据.本算法的优势在于能够快速实现三维动态场景下的集群负载均衡.实验表明,该集群绘制系统可以高效地实现基于Kinect的实时交互式绘制.     

X射线荧光光谱在铝矿石赤泥组分分析中的应用

文介绍X射线荧光光谱在铝矿石，赤泥等材料组分分析中的应用。采用熔融玻璃片和粉末压片法制样，用理论α系数和散射线内标法校正元素间的效应。使用PW2403x射线光谱仪对样品中的Al2O3、SiO2、Fe2O3、TiO2、K2O、NB2O、CaO、MgO、P2O5、灼减、MnO、S、Pb、Zn、Sr、Zr、V、Ga、Cr等19个元素进行测定，其分析结果的精密度和准确度可与化学法相媲美。     

扩大小径管对接焊缝检出范围的滤波方法

从分析X射线检测小径管对接焊缝时散射线对检测的影响出发,提出利用滤波方法来扩大检测范围.分析了滤波片的材料、尺寸以及放置位置对检测范围的影响.实验表明,滤波方法能有效地扩大对接焊缝检出范围,并且操作简单方便.     

电弧超声焊缝跟踪的试验研究

利用声发射探头接收的电弧超声信号进行焊缝跟踪检测。结果表明：对称位置接收到的声发射信号的相位差和幅值差可以作为电弧超声焊缝跟踪的依据。     

碳素材料内部缺陷检测方法的探讨

讨论了产生碳素制品不均质结构和决定材料性能的影响因素,以及由此而产生的结构缺陷对材料内部质量检测的影响。论述了超声波、X射线及声发射三种无损检测方法在碳素材料内部质量检测中的应用状况。在此基础上,通过大量实验,分析对比了三种检测方法在碳素材料内部质量检测中不同的检测效果。提出了超声波脉冲回波法不适合检测碳素制品的内部缺陷,超声波波速分析法适合检测碳素制品均质结构。X射线法是适合定量评价碳素制品内部缺陷的方法。