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931.
932.
Hsin-Yi Liao 《Theoretical chemistry accounts》2009,124(1-2):49-57
The phospha-Wittig reaction HP=PH3 + O=CHX → HP=CHX + O=PH3 (X = H, F, Cl, Me, OMe, NMe2, CMe3) was examined using the density functional theory calculations. All of the structures were completely optimized at the B3LYP/6-311++G** level of theory. The reactivities of various O=CHX were examined by estimating their activation energies. The main finding of this work is that the configuration mixing model can successfully predict the relative ordering of the activation energy and reaction enthalpies of the phospha-Wittig reaction. It was demonstrated that O=CHX with more electro-releasing substituents will possess a smaller singlet–triplet splitting. This will facilitate the phospha-Wittig reaction and will result in a larger exothermicity. 相似文献
933.
Chao-Shang Huang Tianjun Li Wei Liao Qi-Shu Yan Shou Hua Zhu 《The European Physical Journal C - Particles and Fields》2000,18(2):393-403
We reconsider the dimension-11 Planck scale, the physical scale of the eleventh dimension, the physical scale of the Calabi–Yau
manifold and the coupling in the hidden sector in M-theory on . Also we discuss reasonable bounds on them. Considering the F-term of the dilaton and moduli SUSY breaking and choosing two
representative points which correspond to the scalar quasi-massless scenario and the dilaton dominant SUSY breaking scenario,
respectively, we analyze experimental constraints on the parameter space. The sparticle spectrum and some phenomenological
predictions are also given.
Received: 9 June 1999 / Revised version: 12 July 2000 / Published online: 27 November 2000 相似文献
934.
孔洞受压的统一极限分析 总被引:1,自引:0,他引:1
采用俞茂宏统一强度理论分别就平面应变和平面应力总是对受压孔洞进行了极限分析,得到了各自的统一解形式。以往的基于Tresca、Mises、双剪屈服准则以及Mohr-Coulomb强度理论的极限解均为本文统一解的特例。此解可以适应于广泛的不同性质的各灯材料,合理也得出不同材料的相应解。 相似文献
935.
Zhongbing Huang Xiaoming Liao Yunqing Kang Guangfu Yin Yadong Yao 《Journal of colloid and interface science》2009,330(2):399-403
Why is it that drops do not slip down inclined thin fibers or spider silks? The possible explanation is based on the existence of fiber size, which causes a sustaining force that pins these drops. Following this explanation, the drop remains in equilibrium until a critical value of the sustaining force is reached. We suggest an alternative analyses, from the point of view of the inclined fiber at which the drop slips down is predicted. This result does not depend explicitly on silk surface roughness, but only on the drop size and surface tensions. 相似文献
936.
937.
Chang-Kuo Chen Tsung-Wen Lai Jun-Juh Yan Teh-Lu Liao 《Chaos, solitons, and fractals》2009,39(3):1055-1063
This study is concerned with the identical synchronization problem for a class of chaotic systems. A dynamic compensator is proposed to achieve the synchronization between master and slave chaotic systems using only the accessible output variables. A sufficient condition is also proposed to ensure the global synchronization. Furthermore, the strictly positive real (SPR) restriction, which is normally required in most of the observer-based synchronization schemes, is released in our approach. Two numerical examples are included to illustrate the proposed scheme. 相似文献
938.
This paper empirically explores the major considerations associated with Internet-enabled e-banking systems and systematically measures the determinants of customer interactions with e-banking services. The results suggest that perceived usefulness, ease of use, security, convenience and responsiveness to service requests significantly explain the variation in customer interactions. Exploratory factor analysis and reliability test indicate that these constructs are relevant and reliable. Confirmatory factor analysis confirms that they possess significant convergent and discriminatory validities. Both perceived usefulness and perceived ease of use have significant impacts on customer interactions with Internet e-banking services. Perceived security, responsiveness and convenience also represent the primary avenues influencing customer interactions. In particular, stringent security control is critical to Internet e-banking operations. Prompt responses to service requests can encourage customers to use Internet e-banking services. The findings have managerial implications for enhancing extant Internet e-banking operations and developing viable Internet e-banking services. 相似文献
939.
Experimental Techniques - 相似文献
940.
Glycosyl trifluoroacetimidates have been disclosed to be effective glycosyl donors for the synthesis of nucleosides; the present N-glycosylation protocol requires only a catalytic amount of TMSOTf as promoter and proceeds smoothly at room temperature. 相似文献