微米铜丝的低温力学性能测试

针对纤维材料变温环境力学性能测试的需要,在华中科技大学研制的纤维材料试验机的基础上引入了温控装置,从而实现纤维材料在高低温环境下的力学性能测试。采用该装置对不同直径微米铜丝在不同温度、不同拉伸速率条件下的力学性能开展实验研究,测试结果表明弹性模量和抗拉强度随温度的降低而线性增加,屈服强度的变化不太明显。另外,低温环境下微米铜丝的力学性能表现出与其直径相关的尺度效应,而这一现象在常温下一直没有观测到。最后,还研究了拉伸速率对微米铜丝的力学性能影响,结果表明,在现有装置的许用范围之内,拉伸速率对其力学性能的影响不大。     

弹性杆与结构接触冲击的冲击力计算研究

本文提出了一种将杆与结构的接触冲击问题简化为集中力与集中阻尼的常规结构动力学问题的计算模型。对于大型结构，可采用一种特殊的人工边界，只需对人工边界域内的结构用有限元法进行计算。这种人工边界是齐次的，可根据冲击影响区的大小人为地确定     

基于Canny算子的红外图像边缘检测研究

在红外图像处理中,提出了尺度相乘的Canny边缘检测器,定义了尺度相乘函数,该函数是两个尺度检测滤波器响应的乘积.通过确定尺度相乘后的梯度图像,采用非最大值抑制方法得到边缘图像.实验结果表明,该算子提高了传统Canny检测算子的性能,具有良好的检测精度,在定位和噪声抑制两方面得到了较好的折中.     

二维空间中半线性摄动波动方程初值问题解的渐近理论

研究二维空间中具初值问题的半线性波动方程解的渐近理论,在二次连续的古典空间中得到了形式近似解的渐近合理性在长时间范围内成立,这一结果描述了渐近解的长时间存在性.作为所得到的渐近理论的应用,对二维空间中的一个特殊波动方程作出了分析.     

Projected gradient methods for linearly constrained problems

The aim of this paper is to study the convergence properties of the gradient projection method and to apply these results to algorithms for linearly constrained problems. The main convergence result is obtained by defining a projected gradient, and proving that the gradient projection method forces the sequence of projected gradients to zero. A consequence of this result is that if the gradient projection method converges to a nondegenerate point of a linearly constrained problem, then the active and binding constraints are identified in a finite number of iterations. As an application of our theory, we develop quadratic programming algorithms that iteratively explore a subspace defined by the active constraints. These algorithms are able to drop and add many constraints from the active set, and can either compute an accurate minimizer by a direct method, or an approximate minimizer by an iterative method of the conjugate gradient type. Thus, these algorithms are attractive for large scale problems. We show that it is possible to develop a finite terminating quadratic programming algorithm without non-degeneracy assumptions. Work supported in part by the Applied Mathematical Sciences subprogram of the Office of Energy Research of the U.S. Department of Energy under Contract W-31-109-Eng-38. Work supported in part by the Applied Mathematical Sciences subprogram of the Office of Energy Research of the U.S. Department of Energy under Contract W-31-109-Eng-38.     

DATA PREORDERING IN GENERALIZED PAV ALGORITHM FOR MONOTONIC REGRESSION

Monotonic regression （MR） is a least distance problem with monotonicity constraints induced by a partiaily ordered data set of observations. In our recent publication [In Ser. Nonconvex Optimization and Its Applications, Springer-Verlag, （2006） 83, pp. 25-33], the Pool-Adjazent-Violators algorithm （PAV） was generalized from completely to partially ordered data sets （posets）. The new algorithm, called CPAV, is characterized by the very low computational complexity, which is of second order in the number of observations. It treats the observations in a consecutive order, and it can follow any arbitrarily chosen topological order of the poset of observations. The CPAV algorithm produces a sufficiently accurate solution to the MR problem, but the accuracy depends on the chosen topological order. Here we prove that there exists a topological order for which the resulted CPAV solution is optimal. Furthermore, we present results of extensive numerical experiments, from which we draw conclusions about the most and the least preferable topological orders.     

缩尺模型和计算机模拟与大厅音质设计

阐释了缩尺模型的发展,计算机模拟与可听化技术对大厅音质设计不同阶段与程度的辅助功能;介绍了操作缩尺模型时需注意的要点事项,对演算过程的可操作性进行优化建议,同时深化解析了可听化技术的优劣与迷思。     

结合LSTM与CNN的野外车辆声信号分类

针对野外环境下微声传感器采集的小型轮式车、大型轮式车和履带车3种车辆声信号受风噪影响严重、分类性能较低的问题,提出了一种长短时记忆网络(LSTM)与多尺度、多层次特征融合卷积神经网络(CNN)相结合的分类算法——野外车辆识别算法(FVNet).该算法先采用一层LSTM网络提取声信号的时序特征,充分利用声信号的长时依赖关...     

纳米材料的电学、光学和光电性能及应用前景

简要介绍了纳米材料的电学性能以及单电子器件的基本原理和应用；纳米材料的光学性能和光电性能，高的光吸收系数和光致荧光现象可使其应用于敏感元件，由于其光电特性具有超快响应速度，可望在超快光电子器件中得到应用。     

LED全彩大屏幕同步显示系统设计

根据LED全彩大屏幕同步显示控制系统的设计技术指标要求,讨论了系统的组成,确定了以DVI为数字接口,采用串行LVDS传输方式的LED全彩大屏同步显示方案.采用数据重组方法对像素数据进行分场存储,创造性地采用了变频方法对存储数据进行分场扫描,从而实现了无亮度损失的分场显示.对关键模块的仿真结果证明了系统设计的可行.