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141.
On the basis of critical comparison of experimental and theoretical values of the E parameter and investigation of the retardation effect of oxygen on the evaporation rate of ZnO, CdO and HgO, it was concluded that the dissociative evaporation of ZnO and HgO proceeds with releasing of atomic oxygen (O) as a primary product of decomposition. By contrast, the mechanism of dissociative evaporation of CdO corresponds to the equilibrium reaction with releasing of molecular oxygen (O2) as a primary product of decomposition. As was shown, this difference in mechanisms is not related with interatomic OO distances in these oxides. From the analysis of crystal structure for 12 different oxides, which evaporate with releasing of atomic oxygen, and for 13 compounds, which evaporate with releasing of molecular oxygen, it was revealed that the first mechanism is observed for all oxides with the cubic crystal structure. It was proposed that a decisive role in this difference belongs to a local symmetry in the position of O atoms. 相似文献
142.
Software Cold Test Simulation of Coupled Cavity Slow-Wave Structure in Millimeter Wave TWT 总被引:2,自引:0,他引:2
In this paper, the software cold-test simulation method to obtain RF dispersion, interaction impedance by MAFIA software is discussed considering effect of the conducting barrel in the millimeter-wave TWT. The dispersion simulation result is obtained more consistent with experiment data than the method that ignoring effect of the conducting barrel. By changing the structure parameter, high frequency characteristic will be affected. The change relationship of high frequency characteristic with structure parameter is obtained. The different calculation methods of the interaction impedance are discussed. These results are received and are consistent with experiment data. 相似文献
143.
A novel and cost-effective sol-gel process for preparation of MgAl2O4 spinel nanometer powders has been developed in this study. A solution of magnesium and aluminum nitrates in stoichiometric proportion was successfully embraced in the biology polysaccharide gel network, formed by the synergistic interaction between xanthan gum (XG) and locust bean gum (LBG) utilizing their broad-spectrum stability of salt tolerance and character of transformation from sol to gel on the condition of proper temperature and relative proportion of polymeric components. Dry gel could be obtained by vacuum dehydration of aqueous gel at low temperatures. Monolithic MgAl2O4 spinel nanometer powders were produced by calcining the dry gel above 800°C, with average crystallite size of 20 nanometers. 相似文献
144.
145.
Ruili?ZhangEmail author Jianming?Dai Wenhai?Song Yongqing?Ma Jie?Yang Yuping?Sun 《中国科学G辑(英文版)》2004,47(1):113-120
It is helpful to study the photo-induced effect in the perovskite manganites not only for elucidating the mechanism of colossal
magnetoresistance (CMR) effect but also for potential applications in technology. The laser-induced effect in the Co doping
layered perovskite manganites La1.2Sr1.8Mn1.8Co0.2O7, is studied in this paper and the obtained results are also compared with that gained in the Nd-doping manganites with cubic
perovskite structure. 相似文献
146.
M. R. Setare 《International Journal of Theoretical Physics》2004,43(11):2237-2242
We compute particle creation for a real massive scalar field conformally coupled to a spatially closed Robertson–Walker space-time background, with time-dependent scale factor. This is a dynamical Casimir effect with moving boundaries. 相似文献
147.
激发对相干态的等阶Y压缩效应 总被引:16,自引:0,他引:16
用数值计算法研究了激发对相干态|ζ;m〉=a+mb+m|ζ〉的等阶Y压缩效应.结果表明:对于态a+mb+m|ζ〉,光场存在着等阶K(=2,3,4,5,…)次方Y压缩效应,但是随着场模上光子增加数m的增大,等阶K次方Y压缩效应减弱. 相似文献
148.
We use methods of nonequilibrium statistical thermodynamics to investigate two dissipative processes in solids. We find the electron energy losses of a particle moving in a planar channeling regime and the sound absorption coefficient in metals under electron impurity scattering. The oscillator model is used to analyze the contribution from the effect of electron entrainment by a moving scattering center to the total dissipated energy. We investigate the frequency and temperature dependence of energy losses and also the dependence of the absorption coefficient on the sound wave vector. 相似文献
149.
Phenethylammonium-based perovskites, which can be regarded as a semiconductor/insulator multiple quantum well consisting of lead halide semiconductor layers sandwiched between phenethylammonium insulator layers were prepared. To investigate the effects of the electronic state and the orientation of organic insulator layers on the optical properties of layered perovskites, fluorine substituted analogues were also prepared. The structure and optical properties were investigated by the XRD, UV–Vis absorption, and fluorescence measurements. The exciton absorption peak was shifted by the substitution of fluorine atoms in organic ammonium compounds. It became clear that the optical properties of two-dimensional perovskite compounds were controlled by the substitution of fluorine atoms. 相似文献
150.