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纳米级和特型活性碳酸钙的制备 总被引:6,自引:0,他引:6
详细介绍了三种液相法合成纳米碳酸钙的反应系统 :Ca(OH) 2 H2 O CO2 反应系统、Ca2 + H2 O CO2 -3反应系统、Ca2 + R CO2 -3 反应系统 (R为有机介质 )以及每种反应系统的特点 ,综述了利用添加剂控制碳酸钙形状 ,制备链状、立方状、纺锤状、球形、片状等 5种微粉碳酸钙的工艺条件及方法 ,并对碳酸钙的表面活性化处理进行了系统的研究。 相似文献
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采用溶胶凝胶法和共沉淀法制备了2种不同的Cu O-CeO_2-ZrO_2催化剂,并在不同的温度(400℃,500℃和600℃)下进行焙烧,利用X射线衍射(XRD)、程序升温还原(H2-TPR)技术对所制备的催化剂进行了表征,考察了催化剂的CO氧化性能。研究结果表明,共沉淀法制备的Cu O-CeO_2-ZrO_2催化剂的CO氧化活性明显高于溶胶凝胶法制备的催化剂,共沉淀法制备的催化剂表面高分散Cu O的颗粒较大、活性位最多,当焙烧温度为500℃时,CO完全转化时的温度仅为90℃。 相似文献
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《合成材料老化与应用》2015,(4)
采用了表面活性剂-模板法、柠檬酸溶胶-凝胶法及共沉淀法三种制备方法在其余条件相同的情况下制备了一系列催化剂,并采用XRD、H2TPR、CO2TPD、BET等表征手段对它们进行了表征,并对三种催化剂进行了CO2加氢活性评价,结果表明利用柠檬酸溶胶-凝胶法制备的催化剂具有更高的铜分散度,且在活性评价中具有更高的CO2转化率及较高的甲醇选择性。 相似文献
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在醇-水体系中采用共沉淀表面修饰法制备了硫代磷酸烷基酯修饰的Sm2(CO3)3纳米微粒.利用多种分析手段表征了表面修饰Sm2(CO3)3纳米微粒的结构和润滑性能,结果表明形成了以Sm2( CO3)3为纳米核、有机硫磷化合物为表面修饰层在有机溶剂中具有良好分散性的Sm2( CO3)3纳米微粒,作为润滑油添加剂,具有良好的... 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile
Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, 13C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc. 相似文献
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G. R. Hamed 《The Journal of Adhesion》1983,16(1):31-39
A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength. 相似文献
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The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu3Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu3Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters. 相似文献
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责任是人应主动承担的角色义务和对其因过失所造成后果应承担的责罚.有两层涵义:一是义务;二是后果.责任心是个体自觉做好分内事务和履行道德义务的心理倾向,是个性心理品质成分中自我特征维度上的重要内容.责任心具有两个方面的涵义:一是角色分内职责;二是角色道德义务.责任心是一种通过责任认知、责任个性和责任适应的动态形式表现出来的静态品质,责任心是责任心过程结构与责任心关系结构相互制约、相互影响的统一体. 相似文献