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51.
52.
本文获得了有各种相互作用的一般n阶特征量泛函,其耦合系数反映了不同特征量泛函之间的耦合强度.依据定量因果原理,导出了一般n阶特征量泛函的变分原理,获得了一般n阶特征量泛函的Euler-Lagrange方程,它的不同系数可拟合不同的物理现实,如从线性到任意n阶非线性物理系统,使复杂难解的任意n阶非线性物理系统变得具体可解.并获得了该对称变换下不变的m个的守恒量,以及它们之间的关系和统一描述.依据定量因果原理导出了相对性原理,证明了绝对加速参考系、牵连参考系和相对参考系的力都有来自加速度和质量变化的贡献.利用定量因果原理自然导出了广义牛顿第一定律和广义牛顿第二定律,而且还导出了一个新定律,即广义牛顿第三定律,亦即平移不变性系统合力为零定理.进而将研究结论应用于对银河系的修正引力势、分子势、夸克禁闭势等,且其结果与物理实验一致. 相似文献
53.
54.
H. Lee Woodcock Milan Hodošček Paul Sherwood Yong S. Lee Henry F. Schaefer III Bernard R. Brooks 《Theoretical chemistry accounts》2003,109(3):140-148
A replica path method has been developed and extended for use in complex systems involving hybrid quantum/classical (quantum
mechanical/molecular mechanical) coupled potentials. This method involves the definition of a reaction path via replication
of a set of macromolecular atoms. An “important” subset of these replicated atoms is restrained with a penalty function based
on weighted root-mean-square rotation/translation best-fit distances between adjacent (i±1) and next adjacent (i±2) pathway steps. An independent subset of the replicated atoms may be treated quantum mechanically using the computational
engine Gamess-UK. This treatment can be performed in a highly parallel manner in which many dozens of processors can be efficiently
employed. Computed forces may be projected onto a reference pathway and integrated to yield a potential of mean force (PMF).
This PMF, which does not suffer from large errors associated with calculated potential-energy differences, is extremely advantageous.
As an example, the QM/MM replica path method is applied to the study of the Claisen rearrangement of chorismate to prephenate
which is catalyzed by the Bacillus subtilis isolated, chorismate mutase. Results of the QM/MM pathway minimizations yielded an activation enthalpy ΔH
†† of 14.9 kcal/mol and a reaction enthalpy of −19.5 kcal/mol at the B3LYP/6-31G(d) level of theory. The resultant pathway was
compared and contrasted with one obtained using a forced transition approach based on a reaction coordinate constrained repeated
walk procedure (ΔH
†† =20.1 kcal/mol, ΔH
rxn = −20.1 kcal/mol, RHF/4-31G). The optimized replica path results compare favorably to the experimental activation enthalpy
of 12.7±0.4 kcal/mol.
Received: 16 December 2001 / Accepted: 6 September 2002 / Published online: 8 April 2003
Contribution to the Proceedings of the Symposium on Combined QM/MM Methods at the 22nd National Meeting of the American Chemical
Society, 2001.
Correspondence to: H.L. Woodcock e-mail: hlwood@ccqc.uga.edu
Acknowledgements. The authors thank Eric Billings, Xiongwu Wu, and Stephen Bogusz for helpful discussions and related work. The authors also
show grateful appreciation to The National Institutes of Health and The National Science Foundation for support of the current
research. 相似文献
55.
56.
Michel Weïwer Trevor Sherwood Robert J. Linhardt 《Journal of carbohydrate chemistry》2013,32(7):420-427
Floridoside (2-O-glycerol-α-D-galactopyranoside) is a natural glycerol glycoside found in red algae and is believed to play important roles in carbon storage, transport, and assimilation and in the regulation of osmotic balance. We describe here a rapid, high-yield, and high-stereoselectivity synthesis of floridoside in which the key step involves the 1,2-cis O-glycosylation of 1,3-dibenzylglycerol with ethyl 2,3,4,6-tetra-O-benzyl-1-thio-β-D-galactopyranoside using iodonium dicollidine perchlorate (IDCP) or N-iodosuccinimide/trimethylsilyl triflate (NIS/TMSOTf) as promoters. 相似文献
57.
R.O. Ansell T. Dickinson A.F. Povey P.M.A. Sherwood 《Journal of Electron Spectroscopy and Related Phenomena》1977,11(3):301-313
The relative photoionisation cross-sections of the tin 3d and 4d electrons are determined and combined with angular variation studies to establ 相似文献
58.
T. Dickinson A.F. Povey P.M.A. Sherwood 《Journal of Electron Spectroscopy and Related Phenomena》1973,2(4):441-447
An ESCA study of some “intermediate” conductors demonstrates a differential charging effect when the sample block is biased. The variation of the intensity and width of the peak from silver 3d electrons in silver iodide is used to show how the flux of the beam, the conductivity of the sample, the size and polarity of the bias and the grid mounting alter the effect. The results suggest that in unbiased samples differential sample charging contributes significantly to the width of peaks. 相似文献
59.
T. Dickinson A.F. Povey P.M.A. Sherwood 《Journal of Electron Spectroscopy and Related Phenomena》1973,2(5):441-447
An ESCA study of some “intermediate” conductors demonstrates a differential charging effect when the sample block is biased. The variation of the intensity and width of the peak from silver 3d electrons in silver iodide is used to show how the flux of the beam, the conductivity of the sample, the size and polarity of the bias and the grid mounting alter the effect. The results suggest that in unbiased samples differential sample charging contributes significantly to the width of peaks. 相似文献
60.
On the completion of probabilistic metric spaces 总被引:1,自引:0,他引:1
H. Sherwood 《Probability Theory and Related Fields》1966,6(1):62-64