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聚四氢呋喃醚二醇的合成和应用 总被引:5,自引:0,他引:5
本文介绍了聚四氢呋喃醚二醇的合成方法、应用、催化剂的种类以及物理和化学性质。该产品广泛应用于合成聚氨酯、聚氨酯弹性纤维(氨纶)等许多化工产品的生产领域。与由二异氰酸酯类合成的聚氨酯材料、用低聚多元醇合成的聚氨酯弹性体与弹性纤维等材料相比较,该产品性能更为突出。聚四氢呋喃醚二醇的市场需求将会越来越大,尤其对发展我国的氨纶生产,具有广阔的发展前景。 相似文献
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汽车工业滤纸浸渍乳液的研制 总被引:2,自引:0,他引:2
作者介绍了一种汽车工业滤纸浸渍乳液的制备方法.以丙烯酸丁酯、苯乙烯、甲基丙烯酸、硅烷偶联剂和交联型功能单体为主要原料,采用单体预乳化乳液聚合工艺,合成了滤纸浸渍乳液.讨论了单体的选择及配比、硅烷偶联剂、乳化剂对乳液性能的影响.结果表明:软硬单体丙烯酸丁酯与苯乙烯的最佳配比为(0.35~0.47):1;硅烷偶联剂和乳化剂的最佳用量分别为总单体量的0.68%~0.93%、0.45%.制得的乳液粒径细腻、固含量高、黏度适中、稳定性好、综合性能优异. 相似文献
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苯丙乳液及其乳胶漆的制备 总被引:1,自引:0,他引:1
介绍了水作溶剂,以苯乙烯、丙烯酸酯、丙烯酸、聚乙烯醇等共聚合成乳液,在此基础上进一步制备了乳胶漆(内墙涂料),对制得的乳液及内墙涂料进行了测试实验,讨论了影响因素,并给出了乳液和内墙涂料较佳的合成工艺。 相似文献
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本文描述最近引入的新的多功能有源器件—线性变换运算电流放大器的基本性质以及它在电流处理电路中的应用. 相似文献
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聚苯硫醚纤维是一种新型高性能合成纤维,由聚苯硫醚纤维级树脂采用常规的熔融纺丝方法,在高温下进行拉伸、卷曲和切断后制得,具有优异的热稳定性、耐化学腐蚀性、阻燃性等物化性能,在环保、电子、机械、汽车、纺织、航空航天等领域中得到了广泛应用。介绍了聚苯硫醚纤维的物化性能、制造工艺、技术进展、应用前景方面的一些情况,并对目前国内聚苯硫醚纤维产业的发展提出了一些建议。 相似文献
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Pile fabrics are currently enjoying a renewed popularity. They are not only an important upholstery fabric but also are gaining importance in other textile end-uses such as apparel, footwear, toys and accessories. Pile fabrics are made in both natural and synthetic fibres as well as natural and synthetic fibre blends. The study was an attempt to develop a procedure to evaluate the physical properties of pile fabrics to determine their suitability for specific end-uses. The study defined and tested different pile fabric samples which were representative of the 1979 interior textile fabric lines. Six pile fabrics, each with different fibre contents were subjected to seven separate tests and the results reported. The tests included fibre identification, fabric weight determination, fabric thickness determination, breaking load determination, tearing strength determination, and abrasion resistance determination. The results found that pile upholstery fabrics of different generic fibres performed differently when subjected to physical testing. The results obtained from the physical properties tests gave results which can be used to compare pile fabrics of different generic fibre content. 相似文献
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Synthetic polymers are rarely degraded in nature and cause environmental pollution. Biodegradable films have been developed to alleviate the pollution. Many countries have great interests in biodegradable food packaging films. Poly (3‐hydroxy butyric acid) (PHB) is a natural biodegradable plastic with biocompatibility. However, PHB has some problems of application to the food system because it is brittle and stiff. Because PHB has a poor site for chemical modification, the blends of PHB with flexible polymers can overcome these undesirable properties. Therefore, we prepared the blend films of PHB with chitosan, analysed the mechanical properties and barrier properties against water vapour, oxygen and lipid and monitored biodegradability of PHB/chitosan films in this study. The degree of crystallinity of PHB/chitosan films by X‐ray diffraction decreased with increasing chitosan concentration. The granular sizes of the films were reduced with the addition of chitosan to the film in the micro structural observation by a scanning electron microscope. Mechanical properties, including tensile strength and percent elongation of the blend films increased with increasing chitosan ration in the films. It is demonstrated that mechanical properties of the films were improved by the addition of chitosan. The water vapour permeability (WVP) of the PHB film was the highest and WVP was decreased by the addition of chitosan. Oxygen permeability of the films decreased as chitosan amount increased. The films had very good barrier property against lipid. The consumed oxygen of PHB film was greater than that of chitosan film for incubation on the biodegradability determination of the films. Therefore, the blend films could be expected to increase the rate of degradation in natural environments. 相似文献
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对基于Hadamard矩阵的LA码和基于劳伦多项式(Laurent Polynomial)的LS码的生成
及相关特性进行研究,从占空比、相关特性、零干扰窗长度、码字总数等方面仿真分析了LA
S码的性能,并结合实际应用,理论分析了LAS-CDMA系统与传统CDMA系统的归一化容量,仿
真比较了LAS码和Gold序列在准同步CDMA系统中的误码性能。仿真和理论分析表明:LAS码具
有均匀的零干扰窗(Interference Free Window,IFW)特性;不同主码的互相关函数IFW附
近存在较小的副峰,多址干扰较小;在准同步移动通信系统中,LAS-CDMA抗多址干扰性能
明显优于传统CDMA系统,使用 LAS码比使用Gold序列有更好的误码性能。 相似文献
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相对于基于傅里叶变换的频域成像算法,后向投影(BP)算法因采用时域逐点相干积累,更适合于复杂轨迹合成孔径雷达(SAR)高精度成像。但BP算法计算量巨大,限制了其应用于SAR大场景大数据量快速成像。图形处理器(GPU)具有强大浮点运算和并行处理能力,为大场景BP算法快速成像实现提供了途径。结合GPU并行处理,提出了一种基于图像流的复杂运动SAR大场景BP快速成像处理方法。该方法借助BP算法中图像像素点相互独立处理的特性,采用图像像素点并行及图像流程处理,设计了孔径与图像缓存调度方案,提高SAR大场景大数据BP算法成像效率。仿真和机载实测数据结果验证了方法的有效性,在有限GPU显存条件下实现了8 192×8 192大场景快速成像,并且成像加速比相对于传统CPU单线程处理可达300倍以上。 相似文献
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本文基于合成控制法,从反事实的角度,对我国32个城市的2009年4月以来的与房价相关的月度面板数据,结合上海重庆试点城市运用房产税调控政策的效果及敏感度问题进行研究.研究发现:房产税调控政策对不同区域的房价影响不同,如政策对上海市的房价影响效果较明显,上海对政策的敏感度高,但政策过后其房价上升更快;政策对重庆市的房价影响效果不明显,重庆市对政策的敏感度低.因此,提出建议:政策应因地制宜;对关系国计民生的土地及现有住房进行管控,降低存量房;实施保障房建设及住房申请制间接影响房价;将智慧养老与社区养老相结合,提高住房的利用率. 相似文献