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排序方式: 共有871条查询结果,搜索用时 15 毫秒
801.
A. C. Rao 《Journal of Optimization Theory and Applications》1978,24(2):371-374
The ultimate aim of design is optimization. Not much has been reported in the literature on the cost optimization of four-bar function generators. An example problem is solved to illustrate the application of the method. 相似文献
802.
岩石钻爆开挖中预裂缝的隔震效果分析 总被引:13,自引:0,他引:13
通过应力波与由节理刚度系数描述的预裂缝的相互作用分析,考虑预裂缝在爆炸应力波作用下的闭合效应及预裂缝充水等条件下,研究了预裂缝的隔震机制与隔震效果,从而为岩石开挖过程中周边控制爆破方式的优选提供了理论依据。 相似文献
803.
Atomic force microscopy (AFM) is a useful tool, not only for imaging but also for quantification of normal and lateral forces exerted on the AFM tip while interacting with the surface of materials. In order to measure these forces, an accurate determination of the normal and lateral forces exerted on the AFM cantilever is necessary. To date, there is no generally accepted technique for the force calibration of AFM cantilevers. In this paper, we present a critical review of various techniques for measuring cantilever stiffness in the normal and lateral/torsional directions in order to calibrate the normal and lateral forces exerted on AFM cantilevers. The key concepts of each technique are presented, along with a discussion of their advantages and disadvantages. An understanding of the issues involved in the determination of the stiffness is needed for the proper choice and implementation of any given technique. 相似文献
804.
首次用激光布里渊散射方法,研究了自旋波劲度系数D随温度T的变化关系,得到了BCVIG单晶的从室温到居里点温度附近D~T关系。基于自旋波之间相互作用的理论,对实验结果进行了合理的解释。 相似文献
805.
From the crystal chemistry and icosahedral phase, two kinds of coordinational polyhedron with 8-fold rotational symmetry——hexakaicahedra and bicapped antiprism were possibly suggested and their one- and two-dimensional quasilattices were deducted. According to the principle of Bravais in conventional crystallography, four kinds of two-dimensional unit cell have been defined in 5, 8, 10, 12-fold rotational symmetry quasicrystal. The authors considered that quasicrystal is a kind of crystal which possesses an incommensurable translational period. This kind of translation is carried out by inflation or deflation symmetry operation. 相似文献
806.
The structures of gelatin gels have been studied by holographic relaxation spectroscopy (HRS) with fluorescein as a doped tracer. An HRS spectrum with double peaks has been observed. It has been experimentally proven that this anomalous HRS spectrum is related to the structures of the gelatin gels. It is shown that two kinds of gel networks are formed when a gelatin solution is cooled at a rate of 2°C/min to a temperature below the gel temperature. Microviscosity inside one kind of network is about four times lower than inside the other one. One with lower microviscosity is called a coarse network, and it is formed through aggregation of a collagen-like, triple-stranded helix. The other is named a fine network and it is constructed simply by entanglements between polymer chains. The structure of gelatin gel can be considered as a blend of these two networks. By controlling the cooling speed, the structure of gelatin gels can be dominated by either coarse or fine gel networks.Dedicated to Prof. Dr. W. Pechhold on the occasion of his 60th birthday. 相似文献
807.
808.
A biaxial hysteretic model for a structural system incorporating strength deterioration and pinching phenomena 总被引:2,自引:0,他引:2
Shu-Hsien Chao 《International Journal of Non》2009,44(7):745-756
A biaxial hysteretic model is developed to take into account the commonly observed hysteretic characteristics of strength and stiffness degradation, pinching and biaxial interaction. The concept of zero force point is proposed to develop the biaxial hysteretic model. Two non-linear inelastic springs and one linear elastic spring are connected in parallel to define the cyclic behavior of the proposed biaxial hysteretic model. The proposed biaxial hysteretic model is rate-independent and capable of simulating not only global (such as story shear force versus story drift response of the whole structure) but also the local hysteretic behavior of structural member (such as moment versus curvature or plastic rotation response of a structural element). The biaxial cyclic loading test data of six reinforced concrete columns, which are designed for flexural failure and shear failure, are used to validate the proposed biaxial hysteretic model. 相似文献
809.
L. M. Skvortsov 《Computational Mathematics and Mathematical Physics》2008,48(11):2007-2017
A scheme is proposed for solving nonlinear algebraic equations arising in the implementation of the implicit Runge-Kutta methods. In contrast to the available schemes, not only the starting values of the variables but also those of the derivatives are predicted. This makes it possible to reduce the number of evaluations of the function (the right-hand side) at each implicit stage without significantly reducing the accuracy of integration. 相似文献
810.