CBGA组件热变形的2D-Plane42模型有限元分析

本文介绍有限元中的2D-Plane42模型在CBGA组件热变形中的应用，利用有限元的模拟CBGA组件的应变、应力的分布，通过模拟表明有限元法是研究微电子封装中BGA焊点、CBGA组件的可靠性的方法。     

Micromechanical modelling of ductile crack growth in the binder phase of WC–Co

This study focuses on numerical simulation of ductile failure in the Co binder phase of WC–Co hardmetal. The growth of edge cracks under mode I loading is considered. A computational micromechanics approach is taken where the Co binder ligaments are explicitly represented in finite element models. An embedding technique is employed. Crystal plasticity theory is used to represent plastic deformation in the Co ligaments. Crack propagation in the binder is simulated using an element removal technique based on a modified Rice and Tracey model for ductile void growth, and fracture resistance curves are generated. Parameter studies are performed for variations in microstructrual parameters such as numbers of Co ligaments ahead of the crack tip and local Co volume fraction. The importance of thermal residual stresses and finite element mesh density are also investigated.     

POWER OPTIMIZATION OF FINITE STATE MACHINE BASED ON GENETIC ALGORITHM

Using state assignment to minimize power dissipation and area for finite state machines is computationally hard.Most of published results show that the reduction of switching activity often trades with area penalty.In this paper,a new approach is proposed.Experimental results show a significant reduction of switching activity without area penalty compared with previous publications.     

Solution of large deformation contact problems with friction between Blatz-Ko hyperelastic bodies

The present paper is devoted to the analysis of the contact problems with Coulomb friction and large deformation between two hyperelastic bodies. One approach to separate the material nonlinearity and contact nonlinearity is presented. The total Lagrangian formulation is adopted to describe the geometrically nonlinear behavior. Nondifferentiable contact potentials are regularized by means of the augmented Lagrangian method. Numerical examples are carried out in two cases: rigid-deformable contact and deformable-deformable contact with large slips. The numerical results prove that the proposed approach is robust and efficient concerning numerical stability.     

On inversive maximal period polynomials over finite fields

Over finite field GF(q) withq a power of an odd primep, we characterize inversive maximal period polynomials in terms of polynomials of orderq + 1, and then we study some properties of polynomials of orderq + 1.This paper was written while the author was visiting the Institute of Information Processing, Austrian Academy of Sciences, AustriaThe author would like to thank the Institute of Information Processing, Austrian Academy of Sciences, Austria, for its hospitality and for using its facilities     

主动约束层阻尼板结构动力学建模研究

将有限元法和GHM法相结合，给出了建立主动约束层阻尼（ACLD）板结构动力学模型的新方法。建模时，考虑到粘弹材料（VEM）的纵向位移影响，采用GHM方法描述VEM的本构关系，解决了VEM的力学特性随温度和频率变化的难点，避免因VEM的复杂本构关系而产生的微分积分方程。算例表明本文给出的建模方法是准确的，ACLD结构能够有效控制结构振动。     

波动方程正演模型及应用

本采用声波方程，通过四阶有限差分近似，实现了复杂地质构造零炮距的数值模拟。中同时展示实际应用效果。     

纤维素酶分子的计算机辅助序列分析

利用生物大分子数据库（EMBL、SWALL和PDB）及软件技术（DNASIS和AntheProt）对嗜热子囊菌（Thermoascus aurantiacus)的产生的一种纤维素酶分子进行了序列分析及结构预测；通过多种来源的纤维素酶的比较研究，分析了其催化区、活性位点及局部保守序列。     

隔河岩重力拱坝拱座深层处理平面有限元分析

清江隔河岩重力拱坝坝基地质条件复杂，软弱夹层，断裂构造多，岩溶发育，两岸拱座存在局部滑动问题。