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The influence of hydrothermal modification on the structure and hydrodenitrogenation (HDN) activity of NiMo/γ-Al2O3catalyst was studied in the range 140~180 ℃. The experimental results indicated that the hydrodenitrogenation reaction rate of pyridine was accelerated using the NiMo/γ-Al2O3catalyst synthesized via hydrothermal route due to the change of the structure, the increase of the amount of Mo and Ni and the rise of the specific surface area. The change of the structure of catalysts was enhanced at higher hydrothermal temperature, producing NiMo/γ-Al2O3catalyst with better HDN activity. 相似文献
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IntroductionSincethespecialsuperiorityofartificialneuralnetworkstechnologyinvariousengineeringtechniquesfields,suchasoptimization ,associativememories,patternrecognition ,signalprocessingandautomaticcontrol,therehasbeenincreasinginterestintheinvestigati… 相似文献
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1IntroductionConsidertheretardedLi6nard--typeequationwherehisanonnegativeconstant,fitfi,WandgarecontinuousfunctionsonR.Recently,theboundedness,stability,oscillationandperiodicityofsolutionsofwhichisEq.(1)withoutdelayandW(x)=0,hasbeenwidelyinvestigated(of[1-5]).Clearly,iffi(x)=f(x),f200=0,W(x)=0,Eq.(1)isreducedtothewell-knownretardedLi6nardequationIn1963,Krasovskii[6]gaveasufficientconditionoftheuniformasymptoticstabilityofthezerosolutionforEq.(3).Hisworkcausedmuchinterest,itisseenbythewor… 相似文献
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以摩擦基板间的液晶薄层为研究对象,用分子场理论研究了向列相液晶分子排列转变行为.分子质心固定在简单立方晶格的格点上.液晶由极性分子构成,与基板相接触的一层分子同时受到色散和极性两类表面作用.通过自洽的数值计算,获得3种相图,清楚地展示了摩擦基板间向列相出现的从高温沿面到低温垂面排列的转变;获得实现这类转变所需要的两类表面作用的参数范围.结果表明:基板的摩擦会改变基板表面色散作用,但不会影响基板表面极性作用;表面极性相互作用能引起基板间向列相液晶发生沿面到垂面排列转变. 相似文献
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催化剂对纳米聚团床法制备的纳米碳材料形貌的影响 总被引:3,自引:0,他引:3
在纳米聚团床中用催化化学气相沉积法批量制备了碳纳米管,研\r\n究了过渡金属催化剂对碳纳米管形貌和产量的影响.实验结果表明,含\r\n铁催化剂的活性较低,产率较低,但产品质量较好;含镍催化剂的活性\r\n较高,产率较高,但产品质量较差;在钴催化剂作用下发现了一种新型\r\n的针状纳米碳材料.用含载体较少的铁催化剂可以得到纯度较高且微观\r\n结构较好的碳纳米管,但产率较低;不含任何载体的纯镍催化剂则不能\r\n得到碳纳米管.适宜的催化剂组成、催化剂活性点的均匀分布和裂解速\r\n度的控制等构成了纳米聚团床大批量制备碳纳米管技术的关键. 相似文献
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水热改性对氧化铝载体织构和表面性质的影响 总被引:2,自引:0,他引:2
The alumina support was treated in the moderate aqueous hydrothermal condition to avoid from the excess growth of boehmite (AlOOH) crystals which usually results in the obvious decrease of the specific surface area (BET). The experimental results indicated that the hydrothermal treatment of the alumina support at 140 ℃ for 2 hours promoted the formation of the plate-like AlOOH crystallites on the surface of the support via dissolution-precipitation route. The occurrence of the nano plate-like structure led to the improvement in the structural and surface properties, such as the increase of the specific surface area, the surface hydroxyl concentration and the surface acidity. 相似文献