用电控方式实现胶带输送机打滑的保护

作者针对用机械方法实现胶带输送打滑保护的弊端,提出一种简洁、方便、实用的用电控方式解决胶 带输送机打滑保护的思路,对于胶带输送机的安全运行和技术改造都有一定借鉴意义。     

硅橡胶反应性杂化材料制备及其性能研究

以六甲基二硅氧烷、双乙烯基四甲基二硅氧烷和硅酸乙酯为主要原料,合成加成反应型单体。红外和电子透镜分析结果表明,该单体中含有乙烯基、羟基和[SiO1/2]等基本结构,单体中的[SiO2]单元以2～10nm的聚集体形式存在。随该纳米单体的加入,硅橡胶拉伸强度提高为增强前的7～8倍,击穿强度增高4kV·(mm)-1左右;相对介电常数增大,介质损耗也相应发生变化。     

路基压实密度水囊检测方法

介绍了新型水囊式容积测定仪的结构和原理，提出了用新型水囊式容积测定仪测试密度的方法．通过室内和现场对比试验，对新型水囊式容积测定仪测试精度进行了研究，并分析了测试精度对干密度计算值的影响．研究表明，新型水囊式容积测定仪具有仪器轻便、操作简单、测试精度较高的特点，具有较大的应用前景。     

Softballs

There is currently much debate about the safety of the sport of softball. Batted‐ball speed and average pitcher reaction time are factors often used to determine safe performance. Batted‐ball speed is shown to be the most important factor to consider when determining safe play. Average pitcher reaction time is explained and directly correlated to batted‐ball speed. Eleven aluminum multi‐wall, three aluminum single‐wall and two composite softball bats were tested with mid‐compression polyurethane softballs averaging 1721 ±62 N/6.4 mm to represent the relative bat‐ball performance for the sport of slow‐pitch softball. Nine men and six women were chosen for this study out of a test group of over three hundred slowpitch softball players. On average, aluminum bat performance results were within the recommended safety limits established by the national softball associations. However, when composite bats were used, their performance results exceeded the recommended safety limits which can pose a significant safety risk. Using aluminum softball bats, batted‐ball speeds ranged from 80 to 145 km.h^‐1. Using composite softball bats, batted‐ball speeds ranged from 146 to 161 km.h^‐1. The scientific relevance of this study is to provide performance information that can lead to injury prevention in the sport of softball.     

丙烯酸酯橡胶阻尼材料研究进展

分析了高聚物材料的阻尼机理,简要介绍了阻尼性能的评价方法,重点阐述了丙烯酸酯橡胶的共混、共聚、IPN、添加小分子及填充改性制备高性能阻尼材料的研究进展,指出对丙烯酸酯橡胶阻尼材料应用于耐高温环境的阻尼性能缺乏研究,还有待深入,研制集绿色和多功能为一体的新型阻尼材料将是未来高聚物阻尼材料又一个重要的发展方向.     

电梯缓冲器上的橡胶缓冲头性能试验研究

由于橡胶材料具有一定的弹性和较大的阻尼特性,所以在电梯缓冲器上普遍安装橡胶垫起一定的缓冲作用。介绍了在一简易装置上对橡胶缓冲头的刚度和阻尼进行了试验,近似得出了其变化规律。     

Shape memory behavior of SMPU knitted fabric

A preliminary investigation of shape memory (SM) effects of SMPU (shape memory polyurethane) knitting fabric is presented in this paper. Three SMPU knitted fabrics series with different content of SMPU fibers: 100% SMPU, 50% SMPU and 50% cotton, 16% SMPU and 84% cotton are designed and manufactured in our lab. Their shape memory behaviors at different temperatures are characterized in terms of bagging. Our experimental results showed that shape memory effect can be improved with increasing content of SMPU fibers. A comparison between Lycra and SMPU knitted fabrics was also made to validate the shape memory effects of SMPU knitted fabrics.     

西双版纳曼旦村人工橡胶林“退胶还林”经济补偿标准研究

热带雨林是地球的生物多样性宝库,近年人类活动导致全球热带雨林面积不断减少,使得保护雨林、保护环境,促进可持续发展成为当今世界各个国家和人民的共同愿望。从20世纪50年代至今,西双版纳森林覆盖面积减少了近30%,大部分转变为人工橡胶林。面对经济发展与不良生态效应之间的矛盾关系,以政府为主导的有偿“退胶”是在一定程度上拯救雨林的直接途径。本研究采用土地期望值理论和复利计算法,估算出西双版纳曼旦村橡胶林的土地期望值和森林价值,进而制定出“退胶还林”经济补偿标准,并采用了以20年为年限分期付款、征收/租赁的补偿方式。这一研究结果在理论和实践两方面为“退胶还林”面临的实际问题提供了科学的解决方案和参考依据。为促进“退胶还林”的实施,本文还建议在大规模“退胶还林”计划实施之前,要采取政策和措施,尽可能缓解大面积橡胶林对西双版纳当地生态环境的负面影响。     

基于硅胶模具产品快速制造工艺探析

介绍硅胶模具制作、零件浇注的步骤和方法,分析其关键工艺问题．分型面、浇口和排气口的位置以及流道的确定,直接关系到浇注产品能否顺利脱模和产品质量的好坏．浇注速度、固化温度和时间是影响产品性能的重要因素．材料的收缩是影响产品尺寸误差的主要原因．     

耐水性聚碳酸酯聚氨酯-环氧树脂共混物研究(英文)

研究了耐水性聚碳酸酯聚氨酯－环氧树脂共混物（ＰＣＰＵ－ＥＰ）的结构与性能,并采用红外光谱仪、示差扫描量热仪、扫描电镜和动态粘弹谱仪对其进行检测．结果表明,ＰＣＰＵ－ＥＵ在１０／１００（ｗｔ／ｗｔ,ＰＣＰＵ／ＥＵ）时具有优异的耐水性能和力学性能．