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41.
The orientation and concentration distributions of fibres in laminar and
turbulent channel flows are investigated numerically. The obtained results
are in good agreement with the experimental data. In the laminar flow
regime, more fibres orient to the flow direction as the Reynolds number
increases. The shear rate of fluid around a fibre plays an important role in
determining the orientation distribution of fibres, while the fibre density
and the fibre aspect-ratio have marginal influence on the orientation
distribution. In the turbulent regime, the orientation distribution of
fibres becomes more homogeneous with the increase of Reynolds number, and
the concentration profile is flatter than that in the laminar regime. The
fluctuating intensity of fibre velocity in the downstream direction is
larger than that in the lateral directions. 相似文献
42.
43.
44.
Let G be finite group and let S be a subset of G. We prove a necessary and sufficient condition for the Cayley digraph X(G, S) to be primitive when S contains the central elements of G. As an immediate consequence we obtain that a Cayley digraph X(G, S) on an Abelian group is primitive if and only if S−1S is a generating set for G. Moreover, it is shown that if a Cayley digraph X(G, S) on an Abelian group is primitive, then its exponent either is
or is not exceeding
. Finally, we also characterize those Cayley digraphs on Abelian groups with exponent
. In particular, we generalize a number of well-known results for the primitive circulant matrices. 相似文献
45.
JIANG Hua-Liang CHEN Kai-Xian TANG Yun CHEN Jian-Zhong JI Ru-YungShanghai Institute of Materia Medica Chinese Academy of Sciences Shanghai China 《中国化学》1995,13(2):131-140
In this paper theoretical studies were performed on artemisinin (qinghaosu) derivatives with semiempirical quantum chemical methods AMI and PM3. The antimalarial activity -logC has an obvious correlation with the net charge of C(16) and bond orders of bonds O(1)-C(10), O(2)-C(6), O(1)-O(2) and O(5)-C(16). According to the calculation results, we derived structure-activity relationship, presented the probable pharmacophore of qinghaosu derivatives and the interaction fashion between the drugs and the plasmodium receptor. 相似文献
46.
BaFe12O19 fine particles were prepared by the glass-ceramic method with the BaCO3?B2O3?Fe2O3 glass system. The effect of technology factors on the Mössbauer spectra and Hc was investigated. The possible mechanism of magnetization reversal of the BaM fine particles was discussed. 相似文献
47.
本文对一著名的互连网络ISE(Inverse Shuffle Exchange)网络的容错参数K和信息传输延迟参数d进行了深入的理论分析,在没增加任何冗余部件的前提下,设计了一具有一定容错能力(K=2)和延迟数量级最小(d=O(10g2n)的RMISE网络。并给出了该网络在正常和故障情况下的不同寻径算法。 相似文献
48.
耗散粒子动力学(dissipative particle dynamics,DPD)作为一种介观尺度拉格朗日型粒子方法,已经成功地应用于微纳米流动和生化科技的研究中.复杂固体壁面的处理和壁面边界条件的实施一直是DPD方法发展及应用的一个障碍.提出了处理复杂固体壁面的一种新的方法.复杂固体区域通过冻结随机分布并且达到平衡状态的DPD粒子代表;所冻结的DPD粒子位于临近流动区域的一个截距内;在靠近固体壁面的流动区域中设置流动反弹层,当流动DPD粒子进入此流动层后反弹回流动区域.应用这种固体壁面处理方法对简单流动区域的Poiseuille流动和复杂多孔介质内的流动进行了分析.研究表明,这种新的固体壁面处理方法能够有效模拟复杂固体区域,准确实施壁面边界条件. 相似文献
49.
ZOU Wen-Hua TIAN Yuan SHEN Shui-Fa GU Jian-Zhong PENG Bang-Bao ZHANG Di-Da MA Zhong-Yu 《中国物理C(英文版)》2010,34(1)
Recent years have witnessed intense activity concerning the study of nuclei with equal numbers of neutrons and protons (N = Z). Exotic properties have been exhibited in the N = Z nuclei, especially in those with atomic masses around 80. In the present paper, the projected shell model(PSM)together with a relativistic Hartree-Bogoliubov (RHB) theory is used to study the nuclear structure near the N = Z line in the mass A ≈ 80 region. For three Zr isotopes 80,82,84Zr, the projected potential energy surfaces and ground state bands are calculated. It is shown that shape coexistence occurs in all of these nuclei. Moreover, we find that the residual neutron-proton interaction strongly affects the ground state band of 80Zr; however, it slightly modifies those of 82Zr and 84Zr. 相似文献
50.
High pressure X-ray diffraction study of CaMnO3 perovskite 总被引:1,自引:0,他引:1
Using a diamond anvil cell device and synchrotron radiation,the in-situ high-pressure structure of CaMnO3 has been investigated.In the pressure up to 36.5 GPa,no pressure-induced phase transition is observed.The pressure dependence on the lattice parameters of CaMnO3 is reported,and the relationship of the axial compression coefficients is βa >βc > βb.The isothermal bulk modulus K298=224(25)GPa is also obtained by fitting the pressure-volume data using the Murnaghan equation of state. 相似文献