Special-shaped tube drawing forming and conformal optimization of die cavity

Aiming at the issues in quick processing and modeling design of drawing special-shaped tube die, by Conformal Mapping Theory and the numerical trigonometry method of interpolation between odd points and even points, the conformal mapping function is obtained. As the result, three-dimension drawing forming were converted into that of two-dimension problems, and the plastic stream function was analyzed, die cavity modeling and its optimized function were set up. Combining with modern processing technology, NC program and CAM of die cavity can be realized. Taking the drawing forming of hexagon tube with arc radii r and ellipse-shaped tube as instances, the drawing die cavity optimization of special-shaped tube was achieved, as well as, the changing principle of wall thickness was analyzed.     

基于正交试验的注塑成型工艺参数CAE模拟设定

运用基于CAE技术的注塑工艺参数优化配置和注塑工艺方案设计的思想,结合正交试验设计方法对工艺参数进行CAE仿真试验,并以零件翘曲变形为优化目标,通过敏感因子分析,获得最佳工艺参数组合.经注塑机试模和三坐标测量机的检测分析,验证了CAE模拟结果的准确性和最佳工艺参数组合在实际生产中的效果.     

模具生产联合体加工作业统一调度问题的研究

模具生产联合体是由小规模企业组成的模具设计、制造联盟，由于设备、工装和人员分属于不同的加盟企业，其作业排序过程非常复杂。为此提出一种复合式模具生产联合体的生产排序方法：依据基本优先规则首先完成单一工序作业，然后对多工序作业用改进遗传算法进行工艺优化，求出最优解和次优解，再使用评价函数法选择最佳作业路线。该方法在生产试验中取得了良好的成效．能较好满足模具用户和加盟企业两方面的需要。     

数控程序的高效设计及其刀具轨迹优化

介绍了提高数控程序编制效率的途径 ,并以实例说明了如何对数控程序刀具轨迹的质量进行优化 ,对从事数控工艺与编程的技术人员有参考和借鉴的作用。     

基于流场数值模拟的导流堤加固方案优化设计

流态和流速分析是导流堤设计的先决问题。以某沿海水利枢纽导流堤为研究对象,采用有限元数值模拟的手段及平面二维水流数学模型,对其加长加固方案进行对比分析,优选出合理的导流堤结构型式和长度,为工程设计提供理论参考。     

有关C语言教学方法优化的探讨

C语言程序设计是一门重要的课程,却难学难教。教学方法优化十分必要。教学方法优化应从激发学生兴趣入手,采用循序渐进的方式,着重培养学生举一反三的编程能力,引导学生写出高质量的程序,并丰富考核方式。     

A note about the complexity of minimizing Nesterov's smooth Chebyshev–Rosenbrock function

This short note considers and resolves the apparent contradiction between known worst-case complexity results for first- and second-order methods for solving unconstrained smooth nonconvex optimization problems and a recent note by Jarre [On Nesterov's smooth Chebyshev–Rosenbrock function, Optim. Methods Softw. (2011)] implying a very large lower bound on the number of iterations required to reach the solution's neighbourhood for a specific problem with variable dimension.     

Genetic algorithm‐based neural‐network modeling approach applied to AlGaN/GaN devices

An accurate equivalent circuit large‐signal model (ECLSM) for AlGaN‐GaN high electron mobility transistor (HEMT) is presented. The model is derived from a distributed small‐signal model that efficiently describes the physics of the device. A genetic neural‐network‐based model for the gate and drain currents and charges is presented along with its parameters extraction procedure. This model is embedded in the ECLSM, which is then implemented in CAD software and validated by pulsed and continuous large‐signal measurements of on‐wafer 8 × 125‐μm GaN on SiC substrate HEMT. Pulsed IV simulations show that the model can efficiently describe the bias dependency of trapping and self‐heating effects. Single‐ and two‐tone simulation results show that the model can accurately predict the output power and its harmonics and the associated intermodulation distortion (IMD) under different input‐power and bias conditions. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

纳微米聚合物调驱渗流理论模型研究及其应用

纳微米聚合物作为一种新型的逐级调驱剂,可在油层深部发生物理和化学变化,实现液流改向。根据纳微米聚合物调驱渗流特点,此文建立了三维三相三组分纳微米聚合物调驱数学模型,考虑了对流扩散和调驱渗流特性,采用隐压、显饱、隐浓的差分方法求解数学模型,并编制了相应的数值模拟软件。对纳微米聚合物调驱矿场试验区进行了数值模拟研究,分析了纳微米聚合物浓度、段塞长度、段塞组合对开发指标的影响,并制定合理的注入方案,实施后达到了增油降水和提高采收率的目的,与数值模拟预测指标基本符合。     

宽带钢厚度模型的研究与优化

介绍莱钢宽带钢厚度模型的优化,以改善板形,提高控制精度.