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191.
ZSM-5/Y复合分子筛在烃类催化裂化催化剂中的应用研究   总被引:7,自引:1,他引:7  
以大庆减压蜡油为原料,考察了水热脱铝ZSM-5/Y复合分子筛的催化裂化性能,并与经同样条件水热脱铝的ZSM-5和Y型沸石的机械混合分子筛进行了对比研究。结果表明,与机械混合样品相比,复合分子筛具有较大的柴油产率和气体产率,汽油产率降低。从复合分子筛结构和ZSM-5的择形催化两方面分析了复合分子筛和机械混合分子筛裂化性能差别的原因。复合分子筛的聚集体结构不利于大分子进入分子筛结构中进行裂化,有利于汽油组分的裂化。气体数据分析支持了复合分子筛的结构特点。  相似文献   
192.
采用共沉淀法引入Si对SO2-4/TiO2进行改性,制得了SO2-4/Ti-Si-O系列固体超强酸,试样经IR、SEM、XRD表征和低温正戊烷异构化活性测试,发现超强酸中心是硫酸根离子与金属原子Ti结合形成的双配位螯合结构,在超强酸性的样品中TiO2均呈锐钛矿晶型。引入Si仅迟滞TiO2晶化过程,控制Si在SO2-4/Ti-Si-O体系中的含量可以有效调节固体超强酸的酸性,并提高正戊烷异构化反应的选择性。  相似文献   
193.
3-(4-Phenyl) benzoyl propionic acid was used as the starting material for the synthesisof furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9-11). The behaviour of the derivatives of furanones and benzoxazinones toward different nucleophiles is reported.  相似文献   
194.
Most of the mercury and selenium exist in the insoluble fraction of dolphin liver. After the insoluble fraction was digested by alkaline protease in the presence of 1% SDS, approximately 50% of Hg and Se consisted in the supernatant and the others in the residue. Gel filtration chromatography of the hydrolysate showed that 96% of Hg and 87% of Se were combined with the high molecular weight proteins stably, which cannot be substituted by the complex reagents.Mercury and selenium in the residue were confirmed as HgSe crystal.  相似文献   
195.
On the Criteria of Instability for Electrochemical Systems   总被引:7,自引:0,他引:7  
LI  Ze-Lin REN  Bin 等 《中国化学》2002,20(7):657-662
Both cyclic-voltammetry-based and impedance-based experimental criteria that have been developed recently for the oscillatory electrochemical systems are critically appraised with two typical categories of oscillators.Consistent conclusions can be drawn by the two criteria for the category of oscillators that involve the coupling of charge transfer mainly with surface steps(e.g.ad-and desorption)such as in the electrooxidation of C1 organic molecules.Whereas,impedance-based criterion is not applicable to the category of oscillators that involve the coupling of charge transfer mainly with mass transfer(e.g.diffusion and convection) such as in the Fe(CN)6^3- reduction accompanying periodic hydrogen evolution.The reason is that the negative impedance cannot include the feedback information of convection mass transfer induced by the hydrogen evolution.However,both positive and negative nonlinear feedbacks,i.e., the diffusion-limited depletion and convection-enhanced replenishment of the Fe(CN)6^3- surface concentration,that coexist between the bistability,i.e.,Fe(CN)6^3- reduction with and without hydrogen evolution at lower and higher potential sides respectively,are all reflected in the crossed cyclic voltammogram(CCV).It can be concluded that the voltammetry-based criterion(in time domain)is more intuitive,less time-consuming and has a wider range of applications than the impedancebased one (in frequency domain).  相似文献   
196.
Some of the blending interpolation methods (which) stated by a convex combination technique are presented. This includes C1 ,C2 blending triangular interpolanls and C1 -blending quadrilateral inter polanls for surfaces. The mentioned methods can be generalized to the construction of C" blending interpolants.  相似文献   
197.
This article describes a process for the synthesis of diethyl oxalate by a coupling reaction of carbon monoxide, catalyzed by palladium in the presence of ethyl nitrite. The kinetics and mechanism of the coupling and regeneration reaction are also discussed. This paper presents the results of a scale-up test of the catalyst and the process based on an a priori computer simulation.  相似文献   
198.
三唑醇(Triadimenol,又称Baytan)是一种优良的内吸性广谱杀菌剂。谷类作物的种子经处理后,防治病虫害的效果极为突出,可增产粮食20%。此化合物化学名称为1-(对-氯苯氧基)-1-(1′,2′,4′-三氮唑-1′基)-3,3二甲基丁醇-2,结构式(Ⅰ)见后。由于分子中含有两个手性碳原子,故应有四种光学异构体。我们实验室曾分离出毫克量的三唑醇两个非对映异构体(A体和B体),生物测定表明两者的药效有明显差別,并确定有效者为A体。根据~1H-NMR中偶合常数,  相似文献   
199.
Some new derivatives of 3-ethoxycarbonyl-6-bromo-5-hydroxyindoles were designedand prepared, their antiviral activity were determined in cell culture with virus cytopathic effect assay. The results showed compound Ⅶ b, Ⅶ h exhibited potential antiviral activity.  相似文献   
200.
Effects of BaCl_2 on slow vacuolar ion channels on radish by patch-clamp   总被引:2,自引:0,他引:2  
Effects of BaCl2 on slow vacuolar ion channels on radish by patch-clamp YANG Pin (杨 频) & ZHANG Liping (张丽平) Institute of Molecular Science, Shanxi University, Taiyuan 030006, China Correspondence should be addressed to Yang Pin (email: yangpin@sxu.edu.cn)  相似文献   
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