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101.
Carbon fibre reinforced ceramic matrix composites (CMC), originally developed for lightweight heat shields of spacecraft, are used for high performance brake discs in sports cars from different manufacturers. In contrast to the CMC materials for space applications, based on woven fabrics and costly manufacturing methods, these low cost friction materials are produced by liquid silicon infiltration of porous Carbon/Carbon (C/C) preforms, based on short fibre reinforced CFRP green bodies manufactured via warm press technique. In this work, different manufacturing methods for ventilated CMC brake discs are compared to each other, and the development of a new technology for the manufacture of single piece C/C‐SiC brake discs in net shape technique is presented. 相似文献
102.
LIWei XIEQiang 《中国矿业大学学报(英文版)》2005,15(1):1-6
Study on behavior of chlorine contained in oval-shaped densified refuse derived fuel (d-RDF) prepared from municipal solid waste in pyrolysis was carried out by means of temperature-programmed electrical furnace, and the gas evolving from pyrolysis was investigated by FFIR. De-HC1 rate was calculated by determining the emission fraction of HC1 in the flue gas and the fraction of C1 left in the pyrolysis residue. The results show that C1 in the d-RDF releases primarily in the form of HC1 during the pyrolysis, and the initial releasing temperature of HC1 enhances with the increase of heating rate. Meanwhile, the higher the end temperature of pyrolysis, the more the C1 released. De-HCl rate is about 70% when the end temperature of pyrolysis is around 600℃. Besides, mechanism of C1 release is discussed. 相似文献
103.
104.
B. Ouertani J. Ouerfelli M. Saadoun B. Bessaïs H. Ezzaouia J.C. Bernde 《Materials Characterization》2005,54(4-5):431-437
FeS2-thin films with good crystallinity were synthesized by a simple method which consists of sulphuration, under vacuum, of amorphous iron oxide thin films pre-deposited by spray pyrolysis of FeCl3·6H2O (0.03 M)-based aqueous solution onto glass substrates heated at 350 °C. At optimum sulphuration temperature (450 °C) and duration (6 h), black green layers having granular structure and high absorption coefficient (5.104 cm−1) were obtained. The study of the electrical properties of the as-prepared films vs. the temperature variations showed three temperature domain dependence of the conductivity behaviour. The first one corresponds to the high temperature range (330 K–550 K) for which an Arrhenius plot type was obtained. The activation energy value was estimated at about 61.47 meV. The second domain corresponding to the intermediate temperature range (80 K–330 K) showed a variable activation energy between the grain boundaries. The barrier height, q¯, was estimated to 27±0.5 meV, and the standard deviation, qσ, was evaluated at about 14±0.5 meV. We found that at lower temperatures (20 K–80 K), the conductivity is governed by two conduction types. The density of localised states, was about 2.45×1020 eV−1 cm−3. 相似文献
105.
Using photo acoustic technique, the thermal properties of CdS thin films grown by spray pyrolysis are measured. Thermal diffusivity
and conductivity in these films decrease at least two orders compared with bulk. These results are compared with our study
on nano CdS and the other available literature. The comparison is good. The dependence of thermal diffusivity on the thickness
of the layer or the size of the particles on the glass substrate are analysed from the present measurement and discussed.
The dependence of thermal diffusivity on the thickness of the layer on the glass substrate is discussed. 相似文献
106.
热重质谱联用研究兖州煤的热解行为 总被引:19,自引:3,他引:19
利用热重—质谱联用(TG/MS)研究了兖州煤的热解行为、热解气相产物(包括硫分)的在线析出行为以及矿物质对热解气相挥发分逸出的影响;比较了原煤和脱灰煤的TG/MS谱图.结果表明:TG/MS系统在获取煤样热失重信息同时,可以在线监测气相挥发分的选出行为;矿物质对热解过程中H2O,CH4和H2的析出没有影响,但对高温阶段CO和C02的析出有明显的作用.550℃附近硫的逸出产物主要来源于煤中黄铁矿的分解. 相似文献
107.
以流化床反应器为主体对废轮胎热解半焦微观结构的变化进行了研究。主要研究了热解温度、流化状态(床料粒径、流化数)对热解半焦的孔径分布的影响。结果表明,低温下热解所得半焦,200 μm左右的大孔比例很大,中小孔径系还没有得到充分发展。升高热解温度使大孔被破坏,同时中小孔孔系大量形成,使得整个半焦的孔结构以中孔为主,这样得到的半焦将有利于其作为生产吸附大分子污染物吸附剂的前驱物。采用0.135~0.304 mm粒径的床料,改变流化数对半焦的孔结构没有明显的影响,较小流化数也可以得到中孔比例很大的半焦。 相似文献
108.
109.
蒸发式冷凝器结构特点及工程应用 总被引:1,自引:0,他引:1
关朋 《制冷与空调(北京)》2004,4(2):63-66
本文对蒸发式冷凝器的结构、工作原理及安装、使用过程中应注意的问题作一下介绍.并结合工程实例,对蒸发式冷凝器和水冷式冷凝器作综合比较. 相似文献
110.
1 INTRODUCTIONSonolyticdegradationofpollutantshasrecentlyattractedintensiveattention ,includingdegradationofaromaticcompounds[1] ,halogen compounds[2 ] ,treatmentofwastewater[3] ,combinationwithothertechniques[4 ] ,andreactordesign[5] .Extremetem peratureand pressureexistingwithinthecollapsinggasbubbles[6 ] ,leadtothermolyticreactionsandfor mationoffreeradicalspecies[7] .Watermoleculessplittoformhydroxylfreeradicalandhydrogenatom .Hydroxylfreeradicalandtheself combinationproduct ,hydroge… 相似文献