High‐order finite elements applied to the discrete Boltzmann equation

A discontinuous Galerkin approach for solving the discrete Boltzmann equation is presented, allowing to compute approximate solutions for fluid flow problems. Based on a two‐dimensional high‐order finite element and an explicit Euler time stepping scheme, the D2Q9 model is discretized and the results are compared to the exact solution of the Navier–Stokes equation. Four numerical examples are considered, including stationary and instationary problems with curved boundaries. It is demonstrated that the proposed method allows to obtain the desired, highly efficient exponential convergence. Copyright © 2006 John Wiley & Sons, Ltd.     

大圆坯连铸带液芯矫直过程的应力、应变有限元模拟

应用Marc有限元软件对圆坯连铸的连续矫直变形过程进行模拟.以马鞍山钢铁公司大圆坯连铸机为原型,考虑铸坯与辊子的接触状态,建立了圆坯矫直变形模型;模拟分析了大圆坯连铸带液芯矫直过程中坯壳的应力、应变,得到了铸坯在矫直过程中的变形规律,可为铸机矫直工艺及设备设计提供参考依据,从而进一步优化铸坯的矫直变形,以提高圆坯的内部质量和表面质量.     

用等面积圆屈服准则分析复合边坡的稳定问题

采用Mohr-Coulomb等面积圆屈服准则和有限元强度折减系数法分析某工程深基坑复合边坡的稳定问题，提出了在平面应变条件下有限元分析模型的选取、边界条件的处理方法、收敛条件，以及采用大型通用软件ANSYS分析边坡稳定时c、φ值的替换原则；计算出该工程边坡的安全系数为1．718．该方法收敛性较好，计算结果稳定性好．     

P^1＋3中球形非线性脉冲的全局存在性

讨论非线性波动方程{((Э)2t-Δx)uε+F(εα|(Э)tuε|p-1(Э)tuε)=0,(t,x)∈[0,∞[×R3,uε|t=0=εU0(r,r-r0/ε),(Э)tuε|t=0=U1(r,r-r0/ε).解的全局存在性.在建立一些必要的估计的情况下,给出小初值和能量耗散条件下脉冲波的全局存在性,为讨论散射问题作了必要准备.     

Application of Fuzzy-PID Control System in Full-Mechanized Coal Face

The control system, which includes structure, the composition of software and hardware, the form of PID control system and its systematic closed-loop, was used in No.4236 full-mechanized coal face of Xinlongzhuang mine.The typical fuzzy PID control system structure was investigated, and a simplified fuzzy PID control system was taken the place of the complex three-dimension fuzzy controller. Based on the parameter relation between fuzzy controller and normal PID controller, a common method of parameter adjustment of PID controller was summed up and the computer simulation was realized. This system can overcome the problems of large delay, nonlinear, poor running environment and great load change in the full-mechanized coal face. The simulating investigation indicates that the designing method of fuzzy controller is simple and feasible.     

电动振动台扩展台面的动力学性能分析

针对电动振动台系统中的部件——扩展台面，提出了一阶固有频率的有限元算法，建立了模态求解的数学方程式；并根据已有算法和数学方程进行了工程实例计算，计算结果与产品的实测数据吻合，为附加台面的有效设计提供了预评价方法。     

毫米波宽带四加脊圆锥喇叭天线研究

本文利用有限单元法对毫米波宽带四加脊圆锥喇叭天线进行了理论分析和综合优化设计。对于这种形式的毫米波宽带天线在频率范围26—40G内的驻波分布情况进行了重点研究。并且，根据设计尺寸制作了一个实验样品，完成了有关实验，获得了满意的实验结果。     

Design and Fabrication of Drug Delivery Devices with Complex Architectures Based on Three-dimensional Printing Technique

1Introduction Drugdeliverydevices(DDD)playanimportantrole incontrollingthedrugreleaseinadesignedmanner[1].AsanimportantkindofDDD,theimplantableDDDmay beusedtotreatsomedeceases,suchasdiabetes,antibi oticadministration,immunization,andtheboneinfectio ns[2].…     

复杂工程系统基于随机分布的FDD优化算法

随着传感器、图像和数据处理等技术的发展，在炼钢、造纸和化工过程中，反馈量测信息是系统的在线随机输出分布，而并非输出变量在样本时刻的量值，不同于传统的故障检测和诊断（fault detection and diagnosis，FDD）问题，对于一类复杂随机工程系统，基于随机分布函数研究了一种新的优化FDD方法，利用B-样务逼近将输出概率密度函数（PDF）转化成动态权系数，进而建立了带有时滞的非线性不确定性权动态模型，将相应的FDD问题转化成一类非线性不确定时滞系统的FDD问题，基于线性矩阵不等式得到了可行的优化故障检测方法和广义自适应故障诊断算法，仿真实例也表明了该算法的有效性。     

Nonlinear seismic response analysis of reinforced concrete tube in tube structure

Super-highly reinforced concrete tube in tube structure is a developing structure system of high-rise building. The more reasonable derivation process of the multi-vertical-line-element model stiffness matrix is given.On the premise of pointing out the problems of present multi-spring element model, combined with present multivertical-line-element model for analyzing on shear wall, the model is expanded to spatial one, and the stiffness matrix of which is derived. Combined with hysteretic axial model and hysteretic shear model, it is suitable for columns,wall limbs and beams with all kinds of section form. Some examples are calculated and compared with test results,which shows that the models have relatively good accuracy. On the base of the experimental phenomenon and failure mechanism for tube in tube structure specimen, nonlinear seismic responses analysis program on the basis of the advantaged element model for tube in tube structure is developed. Calculation results are in good agreement with those of the pseudo-dynamic tests and the failure mechanism can be well reflected.