上证指数的预测分析

本文根据上海股市2005年6月到2009年8月的上证指数数据,通过建立数学模型的方法,对上海股票市场的走势情况作出了综合评价,建立短期内预测股市发展趋势模型对上证指数进行预测,并通过历史实际数据对模型进行了验证。     

Combined Free and Forced Convection in Vertical Channels of Porous Media

In this paper we investigate the combined free and forced convection of a fully developed Newtonian fluid within a vertical channel composed of porous media when viscous dissipation effects are taken into consideration. The flow is analysed in the region of a first critical Rayleigh number in order to interpret the multiple-valued solutions and discuss their validity. The governing fourth-order, ordinary differential equation, which contains the Darcy and the viscous dissipation terms, is solved analytically using perturbation techniques and numerically using D02HBF NAG Library. A detailed investigation of the governing O.D.E. is performed on both clear fluid and porous medium for various values of the viscous dissipation parameter, , when the wall temperature decreases linearly with height, and the pressure gradient is both above and below its hydrostatic value. Although mathematically the results in all cases show that there are two solution branches, producing four possible solutions, the study of the velocity and buoyancy profiles together with the Darcy effect indicate that only one of the two solutions at any value of the Rayleigh number appears to be physically acceptable. It is shown that the effect of the Darcy number decreases as the critical Rayleigh numbers increase.     

利用生命表函数对银川市职工养老保险基金进行分析预测

利用生命表函数对银川市职工养老基金进行分析预测.研究近期、中期养老保险基金收支、就业、人口、城市化、老龄化的变化态势.提出保持养老保险制度健康持续发展的建议.     

差分—等级依赖效用模型研究

等级依赖效用模型在决策权重设置上存在理论缺陷;差分-等级依赖效用模型在有限理性假设下,考虑结果差分变化对决策权重的影响,提出基于差分的决策权重与概率权重的组合权重控制机制,可克服等级依赖效用模型的缺陷;针对差分-等级依赖效用模型的检验表明模型可很好解释拆分效应;差分-等级依赖效用模型保持了等级依赖效用模型的理论框架,可对人们的风险决策行为做出更好的解释和预测.     

中西医结合治疗急性心肌梗塞25例临床观察

为观察葛根素，硝酸甘汕结合治疗急性心肌梗塞（ＡＭＩ）的疗效，将ＡＭＩ患者４３例随机分为两组，中西结合治疗组（中西组）２５例，给予葛根素，硝酸甘油等药治疗，一般治疗组（对照组）１８例，除不应用葛根素外，其余治疗均与中西组相同，结果表明，中西组的临床症状，心电图及酶学等的改善均优于对照组，中西医结合治疗ＡＭＩ疗效显著，是治疗ＡＭＩ是的一种有效措施。     

The combined energy variational principles in linear elasticity

In this paper, a new kind of mixed energy variational principles in linear elasticity—the combined energy variational principles is presented. First, we define the conjugate body of an elastic body, which is obtained by changing the boundary conditions of the elastic body. Next, we decompose the conjugate body into two component-states, construct functionals of potential energy and complementary energy, respectively, for the component-states and define the additional hybrid energy between the component-states. Thus the functionals of combined energy can be constructed. Three typical combined energy variational principles are demonstrated and the other forms of combined energy variational principles are given. The application of the proposed principles to the calculation of thin plates with complicated boundaries is shown.     

Combined stress waves with phase transition in thin-walled tubes简

The incremental constitutive relation and governing equations with combined stresses for phase transition wave propagation in a thin-walled tube are established based on the phase transition criterion considering both the hydrostatic pressure and the deviatoric stress. It is found that the centers of the initial and subsequent phase transition ellipses are shifted along the σ-axis in the στ-plane due to the tension-compression asymmetry induced by the hydrostatic pressure. The wave solution offers the "fast" and "slow" phase transition waves under combined longitudinal and torsional stresses in the phase transition region. The results show some new stress paths and wave structures in a thin-walled tube with phase transition, differing from those of conventional elastic-plastic materials.     

Experimental strain analysis of the losipescu shear test specimen

An experimental strain analysis of the losipescu shear test specimen was performed, utilizing a 20-ply AS4/3501-6 carbon/epoxy unidirectional composite. Using three-element strain-gage rosettes, it was shown that the presence of loading-point-induced transverse normal strains in the gage section do not affect the measured shear strain. Thus, the shear modulus determined using the standard notch specimen is not affected. Likewise, modulus determination is not influenced by cracking at the notch tips, since this occurs at strains beyond the range over which modulus is determined. To further evaluate the effect of notch-tip cracking, material was removed adjacent to the standard V-notches where these cracks initiate. The measured shear strength was unaffected by removing this material, although the shear modulus was reduced slightly (by as much as eight percent for the more grossly exaggerated geometries). E.Q. Lewis, former graduate student, is now Engineer, Lockheed Corporation.