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1.
纳米碳酸锌的制备和热分解动力学参数的测定 总被引:3,自引:0,他引:3
Nanosized zinc carbonate was prepared in the droplet of nano-reactor based on microemusion. The influences of the concentration of the surfactant and reactant on the diameter of nanoparticles were studied and the kinetic pa-rameters of thermal decomposition reaction were determined. It can be shown from experimental results, the di-ameter of the droplet in the microemulsion which have dissolved reactant zinc nitrate and sal volatile is between 4.9nm and 7.7nm, 6.2nm and 12.4nm, respectively. Nanosized zinc carbonate prepared by the method of mi-croemusion has shown good dispersion, narrow distribution and light agglomeration. The particle size of nanosized zinc carbonate is between 5nm and 40nm, and its kinetic parameters of thermal decomposition reaction-activation energy E and reaction order n are 110kJ·mol-1 and 0.9, respectively. 相似文献
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采用水热法合成RUB-13分子筛,探讨了有机模板剂(OSDA)、硅源、晶化温度和水硅比等制备条件对RUB-13分子筛晶体结构的影响,考察了RUB-13分子筛在甲醇制烯烃(MTO)反应中的催化性能。结果表明,采用1,2,2,6,6-五甲基哌啶(PMP)为有机模板剂、白炭黑为硅源,在晶化温度为170℃的条件下,选择H2O/Si比为100和80时可分别合成出高纯度的低硅铝比(Si/Al=100)和高硅铝比(Si/Al=200)的RUB-13分子筛晶体,且晶粒呈棒状形貌。H-Al-B-RUB-13(Si/Al=200)分子筛用于催化甲醇制烯烃反应时,在400℃下表现出高的低碳烯烃选择性(C2=-5选择性达97. 8%,丙烯选择性为54. 5%),优于传统的H-SAPO-34和H-ZSM-5分子筛催化剂。 相似文献
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Effect of N2 Plasma Annealing of Properties of Fluoring Doped Silicon Dioxide Films with Low Dielectric Constant for Ultra—Large—Scale Integrated Circuits 下载免费PDF全文
The influence of N2 plasma annealing on the properties of fluorine doped silicon oxide (SiOF) films is investigated.The stability of the Dielectric constant of SiOF film is remarkably improved by the N2 plasma annealing.After enduring a moisture absorption test for six hours in a chamber with 60% humidity at 50℃,the dielectric constant variation of the annealed SiOF films is only 1.5%,while the variation for those SiOF films without annealing is 15.5%.Fourier transform infrared spectroscopic results show that the absorption peaks of Si-OH and H-OH of SiOF films are reduced after the N2 plasma annealing because the annealing can wipe off some unstable Si-F2 bonds in SiOF films.These Unstable Si-F2 bonds are suitable to react with water,resulting in the degradation of SiOF film properties.Therefore,the N2 plasma annealing meliorates the properties of SiOF films with low dielectric constant. 相似文献
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The water Cherenkov detector array (WCDA) for the Large High Altitude Air Shower Observatory (LHAASO) will employ more than 3600 hemisphere 8-inch photomultiplier tubes (PMTs). Good time performance of the PMT, especially the transit time spread (TTS), is required for the WCDA. In order to meet the demand of the WCDA experiment, an accurate measurement of PMT TTS based on the photoelectron spectrum is studied. The method is appropriate for multi-photoelectrons and makes it possible to measure the TTS of different photoelectrons simultaneously. The TTS of different photoelectrons for a Hamamatsu R5912 PMT is tested with a specially designed divider circuit. The relationship between TTS and number of photoelectrons is also presented in this paper. 相似文献
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分别以拟薄水铝石、硅溶胶和磷酸为铝源、硅源和磷源,四乙基氢氧化铵为模板剂,采用两步水热晶化法合成出粒径为200~300 nm的纳米级SAPO-34分子筛.采用X射线衍射(XRD)、X射线荧光光谱(XRF)、29Si 、27Al、31P MAS NMR、SEM、BET和NH3-TPD等手段对合成的SAPO-34分子筛进行... 相似文献
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