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41.
Summary Three PEO-PSt-PEO triblock polymers and their parent ho-nopolystyrene have been studied by means of light scattering technique
in chloroform, toluene and ethyl acetate. It has been found that the weight average molecular weights calculated by using
the equation Mapp-
were unbelievable negative values; and the largest deviation appeared for the sample with PEO mole content of about 50%.
Data of PSt-PEO-PSt triblock polymers in literature have been quoted and discussed. 相似文献
42.
Decai Yang Bailan Zhang Yongkuan Yang Zheng Fang Guifen Sun Zhiliu Feng 《Polymer Engineering and Science》1984,24(8):612-617
Great attention has been paid to the toughening of isotactic polypropylene (PP) in recent years in order to make full use of this plastic. This paper presents the results of our study on the compatibility of PP with ethylene-propylene-diene rubber (EPT), polybutadiene rubber (PB) or styrene-butadiene rubber (SBR) through characterization of the blends' morphology, and on. the morphology and properties of binary blends of PP with EPT (EPT/PP) and ternary blends of PP, EPT, and polyethylene (PE) (EPT/PE/PP). Morphological structure of solution blends and the great improvement in low-temperature impact strength and other properties of the mechanical blends have shown the difference among EPT, PB, and SBR in compatibility with PP, the effectiveness of using EPT as PP's toughening agent, and the effect of EPT on EPT/PP blend as both toughening agent and compatibilizer. Addition of EPT to EPT/PP made interesting changes in morphology but no effect on properties was observed. 相似文献
43.
一、前言工业生产中广泛使用的甲醇合成铜基催化剂具有活性高、选择性好、起始活性温度低等优点。但铜基催化剂抗毒性能差,影响了它的使用寿命。铜基催化剂的主要毒物是原料气中所含的 H_2S。铜基催化剂 H_2S 中毒失活研究,国内未见报道,美国的 Wood 等和 Rdvodic 等作过一些研究。本文通过对国产 C207铜基催化剂硫化氢中毒失活动力学的研究,建立描述活性衰退过程的失活动力学方程,得到活性与硫化 相似文献
44.
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46.
Poly(ethylene terephthalate) (PET) was blended with two different poly(oxybenzoate‐p‐trimethylene terephthalate) copolymers, designated T28 and T64, with the level of copolymer varying from 1 to 15 wt %. All samples were prepared by solution blending in a 60/40 (by weight) phenol/tetrachloroethane solvent at 50°C. The crystallization behavior of the samples was studied by DSC. The results indicate that both T28 and T64 accelerated the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of PET crystallization rate was most pronounced in the PET/T64 blends with a maximum level at 5 wt % of T64. The melting temperatures for the blends are comparable to that of pure PET. The observed changes in crystallization behavior are explained by the effect of the physical state of the copolyester during PET crystallization as well as the amount of copolymer in the blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1599–1606, 2002 相似文献
47.
本文针对地铁车厢内控制设备分散的问题,设计了基于TCNRTP的地铁列车控制网络系统。采用NS2网络模拟软件构建的虚拟网络环境,编写消息数据传输层协议,通过测试列控网络的通信效率,得出了影响通信效率的因素;通过配置列控通信设备的基本功能和设定装置运行参数达到配置网络化通信的目的。 相似文献
48.
建设鄱阳湖生态经济区是国家从战略全局和长远发展出发作出的一项重大决策。如何主动策应鄱阳湖生态经济区建设,推动吉安进位赶超、跨越发展,是摆在我们各级政府和科技部门面前一项亟待解决的问题。为此,一是要提高认识,统一思想,切实增强策应规划的使命感和责任感;二是要结合实际,突出重点,全面对接鄱阳湖生态经济区规划;三是要加强领导,落实措施,确保吉安进位赶超、绿色崛起取得明显成效。 相似文献
49.
卢礼华 《武汉理工大学学报(材料科学英文版)》2009,(Z1):186-189
A DC motor and ball-screw-driven stage is studied for long-range nanometer positioning.The closed-loop system with high-gain PID controller is specially designed for high-precision point-to-point (PTP) positioning.A particular input shape of the closed-loop system is proposed to avoid overshoot and vibration by taking into account the nonlinear characteristics of the feed drive.Friction modeling and identification are avoided and the effect of friction is greatly suppressed by the controller.Experimental and simulated results demonstrate long-range nanometer positioning is achieved without overshoot.In PTP positioning from 10 mm down to 5 nm,the positioning error is within ±5 nm and response dynamic is satisfactory. 相似文献
50.
Jianfeng Wu Jian Li Xiaohong Xu Lanfang Yang Jufang Wu Fang Zhao Chuanguo Li 《武汉理工大学学报(材料科学英文版)》2009,24(4):651-653
A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding
SiC ceramic foam as matrix and Na2SO4 as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results
indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs
between Na2SO4 and SiC matrix. Na2SO4 has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage
density and high thermal conductivity, it is suit for energy storage under high temperature.
Funded by the “863” Hi-Tech Research and Development Program of China (2008AA05Z418) 相似文献