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231.
《Surface and interface analysis : SIA》2005,37(8):683-688
Heating (100) silicon at high temperature (say, higher than 850 °C) in H2, cooling to 670–700 °C in the same ambient, and quenching to room temperature in N2 results in environmentally robust, terraced 1 × 1 (100) SiH2. Evidence for this conclusion is based on angle‐resolved x‐ray photoelectron spectroscopy, atomic force microscopy, infrared absorption spectroscopy in the attenuated total reflection mode, thermal programmed desorption, and reflection high‐energy electron diffraction. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
232.
Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate 总被引:2,自引:0,他引:2
Gaojun An Yunqi Liu Yongming Chai Hongyan Shang Chenguang Liu 《天然气化学杂志》2006,15(2):127-133
The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate (CTriMATT) were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Ultraviolet visible (UV-Vis) spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis (TG), differential thermal analysis (DTA) and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption (BET) and scanning electron microscopy (SEM). The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen. 相似文献
233.
234.
Thermal decomposition of transition metal malonates, MCH2C2O4?xH2O and transition metal succinates, M(CH2)2C2O4?xH2O (M=Mn, Fe, Co, Ni, Cu, Zn) has been studied employing TG, DTG, DTA, XRD, SEM, IR and Mössbauer spectroscopic techniques. After dehydration, the anhydrous metal malonates and succinates decompose directly to their respective metal oxides in the temperature ranges 310–400 and 400–525°C, respectively. The oxides obtained have been found to be nanosized. The thermal stability of succinates have been found to be higher than that of the respective malonates. 相似文献
235.
Cu,Pd-ZSM-5上NO分解和CO氧化的催化作用 总被引:4,自引:0,他引:4
双交换Cu,pd-ZSM-5催化剂(Cu交换度为105%,Pd交换度分别为3.4%和33%)对CO氧化反应有活性增强作用,对NO分解反应不存在增强效应.双交换催化剂在于交换程序不同,而表面物种不同,活性组分的分布状态不同,因而有不同的活性.先交换Cu,400℃焙烧后再交换pd的Cu-Pd-ZSM-5催化剂,对上述两类反应的活性存双组分催化剂中均为最高.H_2-TPR谱表明,共交换的Cu-Pd-ZSM-5中尚有部分CuCl+占据了部分交换位置,而使CO氧化活性稍有下降.N_2-DTA和H_2-TPR谱结果表明,Pd交换到Cu-ZSM-5中后,抑制了吸附水和水合铜化合物的形成,由此提高了在200—300℃时氧的吸附量.后者的大小和CO氧化活性有顺变关系.N_2-DTA谱中340—445℃的放热峰可能分别表征了和NO分解活性有关的铜氧桥或把氧桥的形成,该放热峰的峰温愈低,峰面积愈大,则NO分解活性愈高. 相似文献
236.
Bredikhin A. A. Lazarev S. N. Bredikhina Z. A. Savel"ev D. V. Vandyukova I. I. Gubaidullin A. T. Litvinov I. A. 《Russian Chemical Bulletin》2003,52(4):846-852
Crystalline specimens of homochiral and racemic glycidyl p-toluenesulfonate were studied by IR spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis. The melting phase diagram of glycidyl p-toluenesulfonate was constructed. The stacking effect in the crystals of the racemic sulfonate is responsible for a more dense molecular packing, with the result that a heterochiral type of crystallization becomes more favorable. 相似文献
237.
Balek V. Zeleňák V. Mitsuhashi T. Bakardjieva S. Šubrt J. Haneda H. 《Journal of Thermal Analysis and Calorimetry》2002,67(1):83-89
Results of emanation thermal analysis (ETA) characterizing microstructure changes of SiC based materials during heat treatment in argon are demonstrated. This method made it possible to reveal fine changes of the texture of SiC nano-sized powders, SiC micro-sized powders and SiC whiskers under in situconditions of the heating. ETA curves can serve as fingerprints of the respective samples.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
238.
本工作用四种较新的质谱技术(碰撞诱导解离(CID),电荷剥离(CS),电荷分离(CSe),电子捕获诱导解离(ECID)谱研究了邻、间、对溴甲苯和溴化苄四种异构体。四种技术在一定程度上都可区分这些异构体。其中比较四种异构体ECID谱中ECID峰的相对强度可得到满意的区分效果。 相似文献
239.
The effect of pressure during thermal plasma chemical vapor deposition of diamond films has been investigated for a pressure range from 100 to 760 Torr. The maximum growth rate in our experiments occurs at 270 Torr for substrate temperatures around 1000°C. The existence of an optimum pressure for diamond deposition may he related to the balance between generation and recombination of atomic hydrogen and carbon-containing active species in front of the substrate. To estimate the concentrations of atomic hydrogen and methyl radicals under thermal plasma conditions, calculations based on thermodynamic equilibrium have been performed. This approximate evaluation provides useful guidelines because rapid diffusion results in a near frozen chemistry within the boundary layer. The effect of substrate pretreatment on diamond deposition depends on the type of substrate used. Two growth modes have been observed-layer growth and island growth of diamond crystals on various substrates. Screw dislocations have been observed in diamond deposition in thermal plasmas, and defects such as secondary nucleations are more concentrated along (III) directions than along (100) directions. 相似文献
240.
A new technique, called modulated thermogravimetry, is introduced as a tool for obtaining continuous kinetic information for
decomposition and volatilization reactions. The approach makes use of an oscillatory temperature program to obtain kinetic
parameters during a mass loss. MTGA™ may be used under quasi-isothermal conditions to observe a single mass loss or may be
combined with linear heating rate or Hi-Res™ controlled rate thermogravimetry to scan from one mass loss region to another.
Results obtained are in agreement with those obtained by other kinetic methods.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献