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1.
V.I. Kushch I. Sevostianov L. Mishnaevsky Jr 《International Journal of Solids and Structures》2008,45(18-19):5103-5117
The paper addresses the problem of calculation of the local stress field and effective elastic properties of a unidirectional fiber reinforced composite with anisotropic constituents. For this aim, the representative unit cell approach has been utilized. The micro geometry of the composite is modeled by a periodic structure with a unit cell containing multiple circular fibers. The number of fibers is sufficient to account for the micro structure statistics of composite. A new method based on the multipole expansion technique is developed to obtain the exact series solution for the micro stress field. The method combines the principle of superposition, technique of complex potentials and some new results in the theory of special functions. A proper choice of potentials and new results for their series expansions allow one to reduce the boundary-value problem for the multiple-connected domain to an ordinary, well-posed set of linear algebraic equations. This reduction provides high numerical efficiency of the developed method. Exact expressions for the components of the effective stiffness tensor have been obtained by analytical averaging of the strain and stress fields. 相似文献
2.
Antoni Leon Dawidowicz Najemedin Haribash Anna Poskrobko 《Mathematical Methods in the Applied Sciences》2007,30(7):779-787
The problem of the existence of the invariant measure is important considering its connections with chaotic behaviour. In the papers (Zesz. Nauk. Uniw. Jagiellońskiego, Pr. Mat. 1982; 23 :117–123; Ann. Pol. Math. 1983; XLI :129–137; J. Differential Equations 2004; 196 :448–465) the existence of invariant and ergodic measures according to the dynamical system generated by the Lasota equation was proved, i.e. the equation describing the dynamics and becoming different of the population of cells. In this paper, the existence of such measure for the quasi‐linear Lasota equation is proved. This measure is the carriage of the measure described by Dawidowicz (Zesz. Nauk. Uniw. Jagiellońskiego, Pr. Mat. 1982; 23 :117–123). Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
3.
Paul Van Der Meeren Jan Vanderdeelen Leon Baert 《Particle & Particle Systems Characterization》1994,11(4):320-326
Using a monodisperse PMMA dispersion, it was shown that light reflection at the sample cuvette walls may greatly influence the results of both static (SLS) and dynamic (DLS) light scattering experiments. Considering SLS, this reflection phenomenon mostly causes an overestimation of the scattered intensity at high scattering angles, which may give rise to the emergence of an additional, artificial peak in the lower region of the particle size distribution. On the other hand, the influcence of reflection on DLS measurements was shown to be particularly important in the upper region of the particle size distribution. The experimentally observed phenomena were explained from the basic principles of both particle sizing methods. Finally, it was shown that the disturbing effect of reflection could be avoided by modifying either the hardware or the software of the static and dynamic light scattering technique. 相似文献
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The purpose of this paper is to review the mechanisms and available theoretical methods for modeling the strength and failure of thin film/substrate systems 相似文献
6.
Li Zhang James A. Bain Jian-Gang Zhu Leon Abelmann Takahiro Onoue 《Journal of magnetism and magnetic materials》2006
A method of heat-assisted magnetic recording (HAMR) potentially suitable for probe-based storage systems is characterized. In this work, field emission current from a scanning tunneling microscope (STM) tip is used as the heating source. Pulse voltages of 2–7 V were applied to a CoNi/Pt multilayered film fabricated on either bare silicon or oxidized silicon substrates. Different types of Ir/Pt and W STM tips were used in the experiment. The results show that thermally recorded magnetic marks are formed with a nearly uniform mark size of 170 nm on the film fabricated on bare silicon substrate when the pulse voltage is above a threshold voltage. The mark size becomes 260 nm when they are written on the identical film fabricated on an oxidized silicon substrate. The threshold voltage depends on the material work function of the tip, with W having a threshold voltage about 1 V lower than Pt. A synthesized model, which contains the calculation of the emission current, the simulation of heat transfer during heating, and the study of magnetic domain formation, was introduced to explain experimental results. The simulation agrees well with the experiments. 相似文献
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Kadhim H. Al-Obaidi Robert D. Gillard Leon A. P. Kane-Maguire Peter A. Williams 《Transition Metal Chemistry》1977,2(1):64-66
Summary Bis-(5-nitro-1,10-phenanthroline)platinum(II) dichloride and diperchlorate have been prepared. The reaction between the parent cation and hydroxide ion has been studied using 1 FI n.m.r. spectroscopy and found to involve attack at the ligand. The bis-(2,2-bipyridyl)platinum(II) ion has been shown to be highly reactive towards methoxide ion. The dissociation of a 2,2-bipyridyl ligand is preceded by attack at the ligand.Part XI: R. D. Gillard, t.. A. P. Kane-Maguire and P. A. Williams,Transition Met. Chem., 2, 47 (1977).On leave from the University of Baghdad, Iraq. 相似文献
10.
Condensation of bis-(2-chloroethyl)phosphoramidic dichloride with 3′-amino-3′-deoxy-N,N-dimethyladenosine afforded the 2′,3′-cyclicphosphorodiamidate (III). By an improved synthesis, methyl 3-amino-3-deoxy-β-D-ribofuranoside was obtained as a model compound for conversion to the analogous 2,3-cyclicphosphorodiamidate (XII). Existence of the latter as two diastereomers due to phosphorus asymmetry was shown by nmr analysis, using comparison with the 5-(O-p-nitrobenzoate) (XIII) as a basis for assignments. 相似文献