共查询到19条相似文献,搜索用时 140 毫秒
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通过对催化重整反应原理、特性的分析,表明了反应压力控制的重要性,提出了催化重整反应压力自动控制的必要性。对重整装置工艺流程进行了简单描述,提出了控制反应压力的原理、方法和步骤。在实际生产中成功实施,提高了催化重整反应压力的稳定性,优化了装置的运行。 相似文献
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与单金属原子催化剂相比,双金属原子催化剂可以打破反应中间体的吸附能和协同效应的比例关系,在燃料电池相关反应具有良好的活性。本文阐述了用于电催化反应的PdAu双金属催化剂的合成方法以及PdAu双金属催化剂的不同结构对性能的影响,并综述了PdAu双金属催化剂用于燃料电池相关反应(包括氧还原反应、甲醇氧化反应、乙醇氧化反应和甲酸氧化反应)的最新研究进展,最后提出了PdAu双金属催化剂存在的不足并对在燃料电池中高效利用的未来方向提出了个人观点。 相似文献
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合成PEN的酯交换反应工艺优化研究 总被引:1,自引:0,他引:1
以 2 ,6 萘二甲酸二甲酯和乙二醇为原料 ,Zn(AC) 2 为催化剂 ,在选定的反应条件下 ,研究了合成PEN(聚 2 ,6 萘二甲酸乙二醇酯 )的酯交换反应。详细论述了温度、催化剂浓度、反应时间、反应物摩尔配比等反应因素对NDC和EG酯交换反应的影响 ;确定了酯交换反应优化工艺条件 相似文献
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为了进一步探讨硅烷接枝聚乙烯水解交联反应机理及动力学,通过酸、碱和盐催化作用原理,说明了羧酸锡对交联反应的作用,用凝胶含量(G%)指标表征了交联反应程度,讨论了反应条件(温度、催化剂用量、水分扩散速度等)对该反应动力学的影响.结果表明:交联反应程度随催化剂浓度升高和环境湿度增大而增大;利用Arrhenius方程可表征该反应动力学的特征,并可求出交联反应的活化能(39.46 kJ/mol);提高水解温度,可加快水在聚乙烯中的扩散速度,因此,也加快了交联反应.硅烷接枝聚乙烯水解交联反应是关于催化剂和水分浓度的一级反应. 相似文献
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由于直接外加增强体液态法制备颗粒增强铝基复合材料存在诸多的问题,而固-液原位反应法制备铝基复合材料具有外加法所没有的一些优点,因此近年来固-液原位反应法引起了广泛关注。重点概述了接触反应法、混合盐反应法、还原反应法、自然浸润法4种固-液原位反应法制备铝基复合材料的最新研究进展。最后,总结了当前固-液原位反应法遇到的难题,并提出今后固-液原位反应法制备铝基复合材料的研究方向。 相似文献
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反应挤出在聚乳酸合成及改性中的应用进展 总被引:1,自引:0,他引:1
综述了反应挤出技术的特点以及历史发展概况,主要从反应挤出聚合、反应挤出接枝以及反应挤出共混3个方面总结了反应挤出技术在聚乳酸材料的制备和改性中的应用情况,指出了其在聚乳酸材料领域的重要地位,并展望了其在未来的发展趋势. 相似文献
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利用环氧氯丙烷通过非均相共价接枝反应将丝素蛋白分子接枝到聚乙烯醇大分子上,制备了以丝素蛋白分子为支链结构、以聚乙烯醇为主链的新型大分子聚乙烯醇接枝丝素(PVA-g-SF)。介绍了制备反应原理,通过FT-IR、DSC测试对接枝反应进行了验证,并通过单因子实验分析讨论了反应温度、反应时间、丝素溶液浓度对丝素接枝效率的影响,优选出了最佳反应条件。最终发现:丝素蛋白分子成功接枝到了聚乙烯醇分子上,并且当反应温度为40℃、反应时间为4h、丝素溶液浓度为10%时,丝素蛋白的最大接枝效率可达13.54%。 相似文献
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M. Kallio P. Ruuskanen J. Mäki E. Pöyliö S. Lähteenmäki 《Journal of Materials Synthesis and Processing》2000,8(2):87-92
This is a study of the possibility of using the aluminothermic reaction for the treatment of the steel industry by-products consisting of ferric oxides and contamination. The experimenal method consists of mixing of the powder materials followed by initiation of the aluminothermic reaction. The microstructures of the reaction products are analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques. Regardless of the composition of the initial oxide mixture, similar reaction products are formed during the reaction. These reaction products are reduced iron and a slag phase consisting of Al2O3, Fe, and FeAl2O4. As a consequence of the high temperature of the aluminothermic reaction, zinc and lead oxides can be separated from the iron phase during the reaction. The remainder of the contamination is either vaporized or burned during the reaction. It is possible that utilization of the aluminothermic reaction offers an energy-efficient, economic process for the recycling of a variety of different by-products containing ferric oxides. 相似文献
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Petter Holme 《Journal of the Royal Society Interface》2009,6(40):1027-1034
The large-scale properties of chemical reaction systems, such as metabolism, can be studied with graph-based methods. To do this, one needs to reduce the information, lists of chemical reactions, available in databases. Even for the simplest type of graph representation, this reduction can be done in several ways. We investigate different simple network representations by testing how well they encode information about one biologically important network structure—network modularity (the propensity for edges to be clustered into dense groups that are sparsely connected between each other). To achieve this goal, we design a model of reaction systems where network modularity can be controlled and measure how well the reduction to simple graphs captures the modular structure of the model reaction system. We find that the network types that best capture the modular structure of the reaction system are substrate–product networks (where substrates are linked to products of a reaction) and substance networks (with edges between all substances participating in a reaction). Furthermore, we argue that the proposed model for reaction systems with tunable clustering is a general framework for studies of how reaction systems are affected by modularity. To this end, we investigate statistical properties of the model and find, among other things, that it recreates correlations between degree and mass of the molecules. 相似文献
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以水为溶剂,N-异丙基丙烯酰胺(NIPAM)为单体,N,N-亚甲基双丙烯酰胺(Bis)为交联剂,分别通过微波合成法和水浴加热法制备了聚N-异丙基丙烯酰胺(PNIPAM)水凝胶,研究了交联剂浓度、反应时间、反应温度等对反应的影响,及PNIPAM水凝胶在不同温度和pH值下的溶胀性变化。研究结果表明,与水浴加热法相比,微波合成法缩短了反应时间,从10h缩减至1h左右;适当延长反应时间和提升反应温度有利于提高单体转化率。微波法合成PNIPAM的最佳条件为:H2O为溶剂,100℃~110℃反应40 min~60 min,交联剂m(Bis)/m(NIPAM)=5/100,单体转化率97%~98%。而且,微波合成法制备的水凝胶具有更显著的温度和pH敏感性能。 相似文献
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T. Takahashi 《成像科学杂志》2013,61(5-6):212-216
The reaction, in solution, between gelatin and various hardeners has been examined by gel permeation chromatography, HPLC and amino acid analysis. It is concluded that there are two types of crosslinking reaction. One of them is the reaction between the hardener and the lysine and hydroxylysine residues in gelatin, whilst the other is the reaction between the hardener and the amino acid residues, except lysine and hydroxylysine. The crosslinking reactions are influenced by the reaction conditions including pH value, concentration etc. The amount of unrcacted lysine, determined by amino acid analysis, correlates with the reduction in the level of a-component due to the crosslinking reaction. It is considered that the results suggest that interchain crosslinking reactions, at the lysine and hydroxylysine residues, mainly take place in gelatin solution. 相似文献
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Using an original technique, new data for the interfacial reaction in B-Al composites have been obtained. Two stages of the boron fibre/aluminium interface reaction were revealed. In Stage 1, due to the aluminothermal reduction of the oxide film on the boron fibre, finecrystalline rhombohedral boron, alumina and dispersed aluminium borides are formed. The latter are formed by the reaction with the-fine-crystalline boron and do not affect the fibre strength but can contribute to a more intensive interaction. In Stage 2, borides are formed by direct reaction with the fibres, thus seriously reducing their strength. 相似文献
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聚氯乙烯与丁腈橡胶交联反应的分子模拟 总被引:1,自引:0,他引:1
用分子模拟方法对聚氯乙烯(PVC)与丁腈橡胶(NBR)化学交联机理及交联反应位置进行了研究,通过DMol 3计算反应的自由能、活化能和反应热,进而研究他们对交联反应行为的影响。模拟结果显示:在453K时,过氧化二异丙苯(DCP)能够引发NBR发生夺取α-亚甲基活泼氢的反应和双键的加成反应,产生NBR大分子自由基,进而引发NBR的自交联反应,加成反应的速率要快于夺取α-亚甲基活泼氢的反应速率;DCP能够引发PVC发生脱氢反应,形成PVC大分子自由基进而引发PVC的交联,但不能引发PVC发生脱氯的反应;PVC与NBR能够发生共交联反应;NBR的自交联反应最快,PVC与NBR的共交联反应次之,PVC的自交联反应最慢。 相似文献