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排序方式: 共有421条查询结果,搜索用时 31 毫秒
91.
Liao-Ran CAO Chun-Yu ZHANG Ding-Lin ZHANG Hui-Ying CHU Yue-Bin ZHANG Guo-Hui LI 《物理化学学报》2017,33(7):1354-1365
Molecular dynamics simulation (MDS) has gained increasing importance in current-day scientific research, as the supplement, guidance, or even replacement of experiments. In this review, we briefly introduce the history of the development of molecular dynamics simulation, focusing on recent progress including new-generation force fields, modern enhanced sampling schemes, and application for the investigation of complex biomolecules. 相似文献
92.
A complete analysis of the proton magnetic resonance spectra of quinoline1 and isoquinoline2,3 allowed to obtain signs and accurate magnitudes of the 1H-1H inter-ring coupling constants (HIRC). Since corresponding 19F-19F inter-ring coupling constants (FIRC) in perfluoro-quinoline4 and -isoquinoline5 are available it was worthwhile to consider whether a correlation could be established between HIRC and FIRC. A correlation of this kind would be of obvious interest to a better understanding of the transmission mechanism of long-range 19F-19F couplings. 相似文献
93.
The developments of Atomic Force Microscopy (AFM) allow to investigated solid surfaces with a nanometer scale. These techniques are useful methods allowing direct observation of surface morphologies. Particularly in the nuclear track fields, they offer a new tool to give many new informations on track formation. In this paper we present the preliminary results of a new use of this technique to characterize continuously the formation of the revealed track in a cellulose nitrate detector (LR115) after an alpha particle irradiation. For that, a specific cell has been used to observe, by nano-observations, the evolution of track shapes simultaneously with chemical treatment. Thus, the track shape evolution has been studied; visualizing the evolution of the tracks in real time, in situ during the chemical etching process. 相似文献
94.
Richard A. Formato 《Applied mathematics and computation》2011,217(21):8866-8872
An implementation of Central Force Optimization (CFO) utilizing variable initial probes and decision space adaptation is presented. The algorithm is tested against a suite of benchmark functions and CFO’s results compared to those of other algorithms. CFO performs well against the benchmarks, and also in scalability tests in 300-dimensions. 相似文献
95.
K.A. Mohammed A.D. Al-RawasA.M. Gismelseed A. SellaiH.M. Widatallah A. YousifM.E. Elzain M. Shongwe 《Physica B: Condensed Matter》2012,407(4):795-804
Compositions of polycrystalline Mg-Zn mixed ferrites with the general formula Mg1−xZnxFe2O4 (0≤x≤1) were prepared by the standard double sintering ceramic method. The structural properties of these ferrites have been investigated using X-ray diffraction and infrared absorption spectroscopy. The lattice parameter, particle size, bonds length, force constants, density, porosity, shrinkage and cation distribution of these samples have been estimated and compared with those predicted theoretically. Most of these values were found to increase with increasing Zn content. The energy dispersive (EDS) analysis confirmed the proposed sample composition. The scanning electron microscope (SEM) and transmission electron microscope (TEM) micrographs showed aggregates of stacked crystallites of about 200-800 nm in diameter. Far infrared absorption spectra showed two significant absorption bands. The wave number of the first band, ν1, decreases with increasing Zn content, while the band, ν2 shifts linearly towards higher wave numbers with Zn contents, over the whole composition range. The room temperature electrical resistivity was found to decrease as Zn-content increases. Values of the vacancy model parameters showed that the packing factors Pa and Pb decrease, the fulfillment coefficient, α, remains almost constant and the vacancy parameter, β, strongly increases with increasing Zn content in the sample. The small values of Pa, Pb, α and the strong increase of the vacancy parameter, β, indicate the presence of cation or anion vacancies and the partial participation of the Zn2+ vacancies in the improvement of the electrical conductivity in the Mg-Zn ferrites. 相似文献
96.
The measurement of soil reaction forces on a lug of a movable lug cage wheel was carried out in a soil bin. To elucidate the experimental results, a theoretical analysis of soil reaction forces on the lug of the movable lug cage wheel was made by using an analysis of the lug trajectory and a modified theory in soil–vehicle mechanics. The existing theory was modified and adjusted by considering the actual lug trajectory and the soil trench made by the preceding lug. The results showed that the theoretical analysis gave a good representation of the reaction forces measured experimentally. The higher pull and lift forces of the movable lug cage wheel compared with those of the fixed lug wheel was supported by the theoretical analysis. Although the theoretical representation of soil reaction forces should be improved by further works, it is sufficiently accurate to estimate the performance of the movable lug cage wheels by the proposed theory. 相似文献
97.
98.
The infrared and Raman spectra of the cadmiumdiammindibromide with 2H - isotopic substitution, have been measured. In order to examine the transferabilities of the skeletal and -NH3, ligand force constants, a normal coordinate analysis was carried out based on a Local Symmetry Force Field (LSFF). The results support the experimental assignments. 相似文献
99.
Harmonic and anharmonic symmetry force constants matrices have been calculated using a stepwise coupling method for the twelve isotopic species of nitrosyl fluoride, chloride and bromide. The valence force fields derived from the above matrices were used to recalculate the normal frequencies and the potential energy distribution among force constants. The valence force fields are compared with others previously reported obtained by different methods. 相似文献
100.