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991.
李鹏 《新疆师范大学学报(自然科学版)》1998,(4)
本文利用了Visual Foxpro3.0中文数据库语言对图书馆自动化管理系统中流通模块的催还通知子模块进行了设计。 相似文献
992.
This paper evaluates the comfort properties of eightkinds of woven fabric commonly used for children'ssummer wear in Hong Kong,China.Due to the expan-sion of children's wear market and the quality require-ment for parents,objective and subjective measurementsare the main methods used to evaluate the chosen fabricsfor garment deslgners and consumers as reference. Objective measurement was carried out through ex-periments by means of the Kawabata Evaluation Systemfor Fabrics(KES-F).Experimental tests on fabrics in-clude compression,surface,bending,air permeability,thermal and tensile.Subjective measurement was con-ducted by a market research on consumers' opinions onfabrics for children's summer wear in the form of ques-tionnaire survey.These two ways of measurement onfabrics were analyzed and compared. It was found that Fabric Sample 6 which is com-posed of polyester and cotton fibre has the best perfor-mance in terms of its comfort properties.Besides,Sam-ple 4 composes of rayon and cotton fibre also ha 相似文献
993.
龙海如 《东华大学学报(英文版)》1998,(3)
On the basis of a mechanical model, cam-to-needle impact force during weft knitting is analyzed and some needle parameters related to the peak impact forces are presented. An experimental method is built to measure dynamic parameters of needle. Contrast tests of impact forces with different needles show that needle modifications Influence apparently needle parameters and peak impact forces. 相似文献
994.
The mesh efficiency of the planetary mechanism of 2K - H[D] style is discussed. It comes to a new formula. Usually, an approximate value is taken as the mesh efficiency of a planetary mechanism. If the formula is used, the theoretical value of mesh efficiency can be gotten. The theoretical mesh efficiency can help engineers to know the true efficiency of 2K - H[D] style when it runs. The mesh efficiency serves the transmitting efficiency of a planetary mechanism. 相似文献
995.
Torsional Models of Two - ply Yarn 总被引:1,自引:0,他引:1
In this paper,the vector equation of a generaliseddoubly wound helix was derived.Treloar's pliedyarn geometry could be obtained as a special case ofthe generalised doubly wound helix.The shortest fi-bre length around the surface of a helical tube(formed by fibre helices)was determined by apply-ing variational principles.The fibre length as calcu-lated by using Treloar's geometry was compared in-directly with the shortest possible fibre length at dif-ferent levels of yarn deformation when some of Tre-loar's rigid geometrical constraints were relaxed.Anew idea based on non-concentric circles was intro-duced to approximate the fibre helix movement in atwo-ply yarn.A torsional model of two-ply yarnwas developed and the theoretical predictions werecompared with some preliminary experimental re-sults. 相似文献
996.
Research on Tearing Property of Reinforced Plastic Film with Bi - axial Warp Knitted Fabric Skeleton
The specification of laid-in and warp yams,thedensity of fabric and the specification of groundyam are of great importance when the bi-axialwarp knitted fabric being knitted.In this paper,the tearing property of the reinforced plastic filmwith bi-axial warp knitted fabric skeleton istested and analyzed.The resuits show thatamong the three factors,the specification of laid-in and warp yam has the greatest influence onthe tearing strength of the reinforced plastic film,while the rest of them has secondary and lesseffect respectively,and there is exponential re-lation between the tearing strength of the rein-forced plastic film and the number of yams in thedirection of force. 相似文献
997.
A mathematical model to describe the TCS process inPET high-speed melt-spinning is established.The de-velopment of crystallinity,molecular orientation andmorphological features of high-speed-spun PET fiberin TCS process is investigated at take-up speeds rangingfrom 3600-4400 m/min and thermal channel tempera-tures ranging from 160-200℃ by simulation.The pro-files of tensile force,running velocity,temperature,bi-refringence,crystallinity and diameter in the TCS spin-line for various process conditions are obtained.Thepredicted results using this model are compared with themeasured crystallinty,diameter and birefringence.Theresults indicate that they are in fairly good agreement.The"necking point"in the TCS spinline can be predictedby this model,and its position changes with the corre-sponding process parameters such as take-up speed andthermal channel temperature.It is found that the neck-ing point moves towards the spinneret when the take-upspeed or the thermal channel temperature increases. 相似文献
998.
应用变形速率连续可变式热裂纹试验方法(VDR法)研究了碳、钼和稀土元素对奥氏体不锈钢焊缝热裂敏感性的影响。试验结果表明,降低奥氏体不锈钢熔敷金属中的碳含量并加入适量的钼可显著提高焊缝的抗热裂性能。稀土元素对焊缝的抗热裂性也有显著影响,加入适量稀土能减少焊缝中夹杂物的数量和大小,改变其成分及分布,提高抗裂性。但是如果加入过量,焊缝中会形成大量稀土夹杂物,降低奥氏体不锈钢焊缝的抗裂性。 相似文献
999.
研究了夹克泡沫保温管道在保持钢管、泡沫层和夹克管同步变形时,钢管与泡沫、泡沫与夹克间接触面的剪切力,横截面上各部分轴力、应力以及轴向变形。结果表明,各接触面剪切力略大于管道所处环境与夹克间的摩擦阻力,在实际生产中应保证管道中各种材料间的接触面具有一定的抗剪切强度,工程中应尽量减小环境对管道的约束。且在进行强度和变形计算时,可忽略泡沫和夹克的影响。 相似文献
1000.
为了研究和分析石墨纤维表面与孔隙的结构和分形性质,采用场发射扫描电子显微镜、电感耦合等离子体发射光谱仪、全自动物理吸附分析仪对其进行测试与表征.研究结果表明:石墨纤维以圆柱状存在,直径约为12~18μm,表面较光滑,缺陷较少,有利于气体吸附;石墨纤维碳的质量分数约为95.86%,还含有少量的N、H、O、S和微量的Ca、Fe、Mg、Si、Al等元素,生产过程中留下的孔道不多;石墨纤维的比表面积较大,其微孔体积占总孔体积的97.98%,平均孔径在微孔区域,且孔径分布较窄,包含大量0.84nm左右和少量1.21nm左右的微孔,较丰富的微孔结构使其具有良好的吸附性能;石墨纤维的表面与孔隙具有较好的分形特性,分形维数分别为2.11和2.99,是一种有工业前景的吸附材料. 相似文献