基于AutoCAD的有限元建模系统AutoFEM

介绍了基于ＡｕｔｏＣＡＤ平台开发应用程序的主要特点和在ＡｕｔｏＦＥＭ中采用的软件接口方案，数据模型及所见即所得等。     

基于汽车与行人碰撞载荷特点的下肢长骨建模

基于THUMS(total human model for safety)下肢长骨有限元模型, 在材料和单元属性等方面进行了改进. 在详细分 析行人下肢长骨载荷特点的基础上, 采用多种不同载荷工况下较新的生物力学实 验数据, 对长骨模型进行了前-后和外-内加载 方向的准静态三点弯曲验证, 同时对近心端1/3处、中部和远心端1/3处加载的动态三点弯曲 验证. 验证结果表明, 该模型具有较好的生物逼真度, 能够准确地模拟行人下肢长骨的骨折 及碰撞响应, 可用于后续行人下肢模型的开发, 并为行人下肢损伤机理和安全防护研究提供 准确高效的研究手段.     

三维离散网格中的弹性波动

本文采用形式解法研究三维有限元离散模型中波动的传播规律。文中由波动方程得到它的特征方程，进而给出了三维离散网格中波的频散关系，分析了三维网格中平面波、非匀匀波、寄生振荡及其它可能存在的运动形式的基本特点；详细讨论了平面波的频散、截止频率及偏振漂移等重要的不同于连续介质中的波动传播性质的特点，提示了其中不同于低维网格中 波动的现象。     

ELASTIC WAVES IN 3-D DISCRETE GRIDS

Wave motion in finite element models presents some characteristics different from thoseof wave motion in continuum,which leads to the errors and other special phenomena in finite elementsimulation of wave motion.The wave propagation in a 3-D finite element model is studied by utilizingthe formal solution in the paper,and the corresponding dispersion relations are derived.Then the mainproperties of wave motion in 3-D grids such as dispersion,cut-off frequency and polarization drift arediscussed.Characteristics different from those of wave motion in 2—D grids are revealed.     

Coupled viscoplasticity damage constitutive model for concrete materials

A coupled viscoplasticity damage constitutive model for concrete materials is developed within the framework of irreversible thermodynamics.Simultaneously the Helmholtz free energy function and a non-associated flow potential function are given, which include the internal variables of kinematic hardening,isotropic hardening and dam- age.Results from the numerical simulation show that the model presented can describe the deformation properties of the concrete without the formal hypotheses of yield criterion and failure criteria,such as the volume dilatancy under the compression,strain-rate sen- sitivity,stiffness degradation and stress-softening behavior beyond the peak stress which are brought by damages and fractures.Moreover,we could benefit from the application of the finite element method based on this model under complex loading because of not having to choose different constitutive models based on the deformation level.     

星形裂纹的应力分析

利用复变函数的方法, 通过构造适当的保角映射研究了星形裂纹的平面弹性问题,给出了裂纹尖端I型与II型问题应力强度因子的解析解.并由此模拟出了经典的Griffith裂纹,共点均匀分布三裂纹,十字裂纹,对称八裂纹问题.      

陆地棉体细胞胚胎的发生和遗传转化条件初探

以陆地棉（冀棉20）下胚轴为外植体，在含KT0．3mg／L和2，4－D0．08mg／L的MS培养基上，诱导产生了胚性愈伤组织，继代培养不需要添加激素，胚性愈伤组织即分化为胚状体，并萌发出小芽，胚状体萌发过程与合子胚相似，但出现了一些畸形胚，解剖学方法观察发现，这些畸形胚的维管束系统不明显或形态异常，以农杆菌介导法对冀棉20胚状体及胚性愈伤组织进行了雪花莲凝集素（GNA）基因的遗传转化条件探索，并以GUS基域瞬间进行检测加以证实，得出农杆菌的浓度为O．D600＝0．8时，浸染时间为5min，共培养时间为3d，筛选培养基中卡那霉素浓度为75mg／L，对冀棉20胚状体及胚性愈伤组织转化是较为适合的。     

Block Transformation of Hybrid Cellular Automata

By introducing a sequence-block transformation and vector-block transformation, we explore the dynamical properties of hybrid cellular automation (HCA) and hybrid cellular automation with memory (HCAM) in the framework of symbolic dynamics. As the local evolution rules of HCA and HCAM are not-uniform, the new uniform cellular automata (CAs) with multiple states are constructed by specifical the block transformations. Furthermore, because the new CA rules are topologically conjugate with the originals, the complex dynamics of the HCA and HCAM rules can be investigated via the new CA rules.     

Oxidation of isobutane over hydrothermally synthesized Mo-V-Te-Nb-O mixed oxide catalysts

MoV_0.3Te_0.17 and MoV_0.3Te_0.17Nb_0.12 catalysts were prepared by a hydrothermal synthesis route and tested for the oxidation of isobutane and isobutene. Characterization results showed that the structure and property of Mo-V-Te-based catalysts are relatively different depending on the presence of the Nb element. Catalytic tests showed that the selectivity of methacrolein can comparatively be improved by the addition of Nb into the MoV_0.3Te_0.17 catalyst for the selective oxidation of isobutane.