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991.
992.
Xinhua Liang Zhentao Mi Yaquan Wang Li Wang Xiangwen Zhang 《Reaction Kinetics and Catalysis Letters》2004,82(2):333-337
The ammoximation of acetone to acetone oxime with 30 wt.% hydrogen peroxide over TS-1 has been studied. The conversion of
acetone and the selectivity to acetone oxime can reach 99% and 94%, respectively. The by-products are the corresponding hydrazone,
imine and small amounts of unidentified compounds. The influence of various parameters such as solvent, temperature, amounts
of catalyst and the NH3 to acetone molar ratio were investigated.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
993.
994.
W. Shi Y.J. Ding C. Fang Q. Pan Q. Gu 《Applied Physics A: Materials Science & Processing》2003,77(3-4):567-570
The optimal corona-poling temperature of polymer films was accurately determined by measuring the temperature dependence of the in situ second-harmonic (SH) intensity profile under the applied poling electric field. The in situ SH intensity profile was first measured by probing both the surface voltages and the poling currents induced by surface/space charges for the corona-poled polymer films. Moreover, charge effects on the stability of the chromophore orientation were first studied by using the thermally stimulated discharge-current technique. PACS 72.20.Jv; 42.65.Ky; 73.61.Ph; 81.40.Tv 相似文献
995.
由于含时波包方法具有经典的直观又不乏量子力学的准确 ,选择含时波包方法来处理F +CH2 D2 →CH2 D/CHD2 +DF/HF反应 .把半刚性振转子 (SVRT)模型应用到该反应体系中 ,研究了两个通道中该反应从基态反应物开始在修正过的J1(MJ1)势能面上计算出来了反应几率、积分截面、速率常数 .反应几率随能量变化的图的数值结果给出了振荡结构 ,这些振荡结构是可以和动力学振荡联系起来的 .而这些振荡结构在积分截面随着能量变化的图中就被反应几率求和后的平均结果所掩盖了 .速率常数和实验结果的比较也得到了较好的结果 . 相似文献
996.
The electronic structures of ABi2Ta2O9 (A=Ca, Sr, and Ba) were calculated by using first-principles under optimized structure. As the size of A-site cation decreases from that of Ba2+ to Ca2+, the band-gap between O 2p and Ta 5d increases from 2.0 to 2.9 eV, which responses to the stronger orbital hybridizations between Ta 5d and O 2p orbits favoring improvement of the ferroelectric property, decrease in leakage current, and increase in both spontaneous polarization and Curie temperature by the structural distortion. In contrast to CaBi2Ta2O9 and SrBi2Ta2O9, the hybridization between Ba 5p orbits and O 2p orbits in BaBi2Ta2O9 has better structural stability. 相似文献
997.
998.
Millimeter-sized molybdenum nitride (MoN), in the forms of fiber-like prisms or hollow tubes, has been successfully synthesized via thermal ammonolysis of molybdenum polysulfide precursor. The initial morphology of the precursor is well preserved in the final product. This method could be expanded to preparation of other fiber-like nonmetal ceramics without addition of template. The polysulfide precursor (abbreviated to PS), hydrothermally prepared at 30°C (PS1) or 150°C (PS2), was characterized by various methods for better comprehension of the sulfide-nitride topotactic conversion model. 相似文献
999.
Envelop solitons in dusty plasmas for warm dust 总被引:1,自引:0,他引:1
A nonlinear Schrödinger equation is obtained for the warm dusty plasmas. The modulational instability of envelop soliton is investigated in this paper. Both the temperature of the dust grains and the charge variations of dust grains affect the instability regions of the dusty plasmas. It also affect the amplitude and the width of the envelop soliton. 相似文献
1000.
El Kebir Boukas Peng Shi Sing Kiong Nguang 《Journal of Mathematical Analysis and Applications》2003,282(1):241-255
This paper studies the problem of stochastic stability and disturbance attenuation for a class of linear continuous-time uncertain systems with Markovian jumping parameters. The uncertainties are assumed to be nonlinear and state, control and external disturbance dependent. A sufficient condition is provided to solve the above problem. An H∞ controller is designed such that the resulting closed-loop system is stochastically stable and has a disturbance attenuation γ for all admissible uncertainties. It is shown that the control law is in terms of the solutions of a set of coupled Riccati inequalities. A numerical example is included to demonstrate the potential of the proposed technique. 相似文献