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Optimization of CHARMM force field parameters for the chalcone fragment
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作者 ZHANG Hui YAO Yuan +1 位作者 QI XiaoLi LI ZeSheng 《Science China Chemistry》 SCIE EI CAS 2012年第12期2580-2586,共7页
In this work,we developed the CHARMM all-atom force field parameters for the nonstandard biological residue chalcone,followed by the standard protocol for the CHARMM27 force field development.Target data were generate... In this work,we developed the CHARMM all-atom force field parameters for the nonstandard biological residue chalcone,followed by the standard protocol for the CHARMM27 force field development.Target data were generated via ab initio calculations at the MP2/6-31G* and HF/6-31G* levels.The reference data included interaction energies between water and the model compound F(a fragment of chalcone).Bond,angle,and torsion parameters were derived from the ab initio calculations and renormalized to maintain compatibility with the existing CHARMM27 parameters of standard residues.The optimized CHARMM parameters perform well in reproducing the target data.We expect that the extension of the CHARMM27 force field parameters for chalcone will facilitate the molecular simulation studies of the reaction mechanism of intramolecular cyclization of chalcone catalyzed by chalcone isomerase. 展开更多
关键词 CHARMM force field parameters CHALCONE
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Energy of the Gravitational Field as an Equivalent of the Dark Energy of the Universe
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作者 Valentyn Nastasenko 《Journal of Applied Mathematics and Physics》 2021年第7期1541-1548,共8页
Determination of the structural foundations and parameters of the Universe is an important urgent task since it enables us to understand and explain the structure and basic parameters of the material world. Herewith, ... Determination of the structural foundations and parameters of the Universe is an important urgent task since it enables us to understand and explain the structure and basic parameters of the material world. Herewith, it is necessary to be aware of modern problems of physics and possible ways to solve them. Among such problems, hypotheses concerning dark matter and the energy of the Universe occupy an important place. However, the determination of their on the basis of modern theories still leads to abstract equations that do not give concrete results;therefore, they have a level of hypotheses. A number of initial scientific propositions based on this abstract of mathematical dependencies have controversial meanings. Elimination of this disadvantage is the main goal of the work performed. Its main difference and scientific novelty are the justification of the energy parameters of the gravitational field of the Universe, the magnitude of which can replace its dark energy and dark mass. The solution to this problem is justified by strict physical dependencies, which are obtained on the basis of fundamental physical constants. It is an urgent and important scientific and applied problem, since it develops knowledge about the gravitational field and the material world in general. The performed work is based on the methods of deduction and induction in the research of the material world based on the application of the well-known reliable laws of physics and the general principles of the development of the theory of knowledge. Other research methods are still unknown, since the work performed is associated with new scientific discoveries, the search for which is difficult to formalize by technique methods. The results of the study consist of the analysis of wave, force and energy parameters of the relict gravitational field of the Universe. The calculated value of this energy is 1.58 × 10<sup>70</sup> J. This energy is enough to cover the amount of dark energy and mass in the Universe, which casts doubt on their existence. Conclusions: This paper can supplement previously performed research on the dark mass and energy of the Universe, which requires further for their reconciliation. 展开更多
关键词 Wave force and Energy parameters of the Relict Gravitational field of the Universe and the Possibility of Replacing of Them Dark Energy and Mass
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