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71.
Gang Lv Fadong Wei Hui Jiang Yanyan Zhou Xuemei Wang 《Journal of Molecular Structure》2009,915(1-3):98-104
Density functional B3LYP method with 6-31++G** basis set is applied to optimize the geometries of the luteolin, water and luteolin–(H2O)n complexes. The vibrational frequencies are also studied at the same level to analyze these complexes. We obtained four steady luteolin–H2O, nine steady luteolin–(H2O)2 and ten steady luteolin–(H2O)3, respectively. Theories of atoms in molecules (AIM) and natural bond orbital (NBO) are used to investigate the hydrogen bonds involved in all the systems. The interaction energies of all the complexes corrected by basis set superposition error, are within −13.7 to −82.5 kJ/mol. The strong hydrogen bonding mainly contribute to the interaction energies, Natural bond orbital analysis is performed to reveal the origin of the interaction. All calculations also indicate that there are strong hydrogen bonding interactions in luteolin–(H2O)n complexes. The OH stretching modes of complexes are red-shifted relative to those of the monomer. 相似文献
72.
73.
José F. Cariñena 《Reports on Mathematical Physics》2007,60(2):237-258
A rigorous geometric proof of the Lie theorem on nonlinear superposition rules for solutions of nonautonomous ordinary differential equations is given filling in all the gaps present in the existing literature. The proof is based on an alternative but equivalent definition of a superposition rule: it is considered as a foliation with some suitable properties. The problem of uniqueness of the superposition function is solved, the key point being the codimension of the foliation constructed from the given Lie algebra of vector fields. Finally, as a more convincing argument supporting the use of this alternative definition of superposition rule, it is shown that this definition allows an immediate generalization of the Lie theorem for the case of systems of partial differential equations. 相似文献
74.
75.
One of the major applications for dielectrophoresis is selective trapping and fractionation of particles. If the surrounding medium is of low conductivity, the trapping force is high, but if the conductivity increases, the attraction decreases and may even become negative. However, high-conductivity media are essential when working with biological material such as living cells. In this paper, some basic calculations have been performed, and a model has been developed which employs both positive and negative dielectrophoresis in a channel with interdigitated electrodes. The finite element method was utilized to predict the trajectories of Escherichia coli bacteria in the superpositioned electrical fields. It is shown that a drastic improvement of trapping efficiency can be obtained in this way, when a high conductivity medium is employed. 相似文献
76.
77.
The experimental results of viscoelastic mechanical tests, at five different levels of conversion, are reported for a thermoset
composite matrix system toughened with an appropriate percentage of a thermoplastic polymer. The results from static tests
are used to construct the master curves at a specific degree of cure, while the shift factors are compared with the corresponding
values from dynamic experiments in order to assess the validity of the time-temperature superposition for each conversion.
Neat resin plates were cured accurately, according to the full kinetics model for a dynamic and isothermal temperature regime;
the conversion gradient in the plane and across the thickness of the plates was assessed by a thermal analysis of samples
taken from different locations before extracting the samples from them. The viscoelastic behaviour of the resin matrix showed
a sensible difference in the relaxation time spectrum upon conversion according to the provisional trend of mobility theory;
a higher conversion induced a horizontal shift of the principal relaxation time for each level of conversion, which could
be related very well to the glass transition at the same conversion. Good results were also obtained for the ultimate modulus
of the resin at a temperature just before the onset of the co-curing phase for partially cured samples.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 2, pp. 265–278, March–April, 2008. 相似文献
78.
We clarify once again that Kabsch's method and the Quaternion method are mathematically equivalent methods, that is, that they contain identical information and, when properly understood and applied, lead to identical answers to any questions regarding least-squares rotational superposition, either by proper rotations or by rotation-reflections. We also provide the correct bounds for the eigenvalue spectrum. 相似文献
79.
80.
提出一种基于波叠加法的近场声全息空间分辨率增强方法. 该方法在波叠加法的基础上,利用全息面声压信号求得布置在全息面附近的虚源面上的简单源源强,再根据求得的简单源源强实现对全息面声压的插值,进而利用插值后的全息面声压数据进行重建. 该方法可以提高近场声全息重建图像的空间分辨率,减少测量工作量,简化测量过程. 通过仿真对影响插值结果的参数进行了分析,给出了合理的选取范围;通过仿真和实验研究验证了该方法的有效性.
关键词:
波叠加法
近场声全息
空间分辨率 相似文献