级配碎石基层非线性对沥青路面结构受力的影响

目的基于级配碎石基层材料的非线性特征,研究级配碎石上基层沥青路面结构力学响应规律,进而为该种路面结构设计提供理论依据．方法通过ABAQUS有限元软件的二次开发,运用Fortran语言对级配碎石非线性本构模型进行编译,建立级配碎石上基层沥青路面结构的有限元模型．结果随级配碎石层和面层厚度的增加,级配碎石非线性沥青路面结构各结构层所受层底拉应力较级配碎石线弹性沥青路面结构都有所增加,路表弯沉变化不大．推荐在中等级交通下的面层厚度为7—15cm,级配碎石层厚度为10—15cm．结论应用该种路面结构时,考虑到级配碎石层非线性对该路面结构受力产生的不利影响,必须确定合理的级配碎石层和面层厚度．     

多项式微分方程的广义反射函数及其周期解

为了研究多项式微分方程周期解的存在性与稳定性,通过多项式微分方程的广义反射函数来寻找其Poincaré映射.给出了多项式微分方程具有线性广义反射函数的充要条件,以及在该条件下线性广义反射函数的具体表达式和多项式微分方程周期解的存在性与稳定性.该结果对研究相关微分方程周期解与稳定性具有一定的参考价值和指导意义.     

均匀平面电磁波的极化及基于HFSS极化状态的课堂展示

极化是描述电磁波和天线的重要参量之一,是电磁教学中的重要知识点,在卫星广播、雷达、航空航天遥感等领域中有着广泛的应用。介绍电磁波极化这一概念,分析均匀平面电磁波极化的成因,并基于电磁分析软件HFSS(high frequency simulator structure),呈现了线极化及圆极化波增益图形曲线。课堂中引入仿真图形及数据,增加学生的感性认识及兴趣,使得教学效果得到改善。     

反射衰减诊断激光光束的应用分析

介绍了普通光学元件反射诊断激光光束的应用,提出了利用平面平晶的平面反射进行光能衰减,详细论述了采用该方法进行光能衰减的可行性,分析了平面平晶反射衰减中反射光S偏振态和P偏振态能量的差异,对激光束诊断的影响和解决方法,结合半导体绿激光器的光束诊断进行了应用分析。实验证明,该方法结构简单、调整方便、误差小,利用普通平面平晶反射衰减即可满足激光强度的匹配要求,实现了待测激光束无失真取样,达到很好的测试效果。     

Effect of extrusion wheel angular velocity on continuous extrusion forming process of copper concave bus bar

The continuous extrusion forming process for producing large section copper concave bus bar under different extrusion wheel angular velocities was studied by three-dimensional finite element technology based on software DEFORM-3D. The rigid-viscoplastic constitutive equation was employed in the model. The numerical simulation results show that the deformation body flow velocity in the die orifice increases gradually with the increase of the extrusion wheel angular velocity. But slippage between the rod and extrusion wheel occurs when the extrusion wheel angular velocity is high. The effective stress near the die orifice enhances gradually with increasing extrusion wheel angular velocity. High stress is concentrated in adjacent regions of the flash gap. The effective strain gradient is greater near the abutment than that near the die orifice. The effective strain of the product increases gradually with increasing extrusion wheel angular velocity. In the deformation process, the deformation body temperature increases remarkably due to friction and deformation. So the cooling is necessary in the region of the die and tools.     

Evaluation of TiAI and 40Cr diffusion bonding quality using ultrasonic reflection spectrum

Combined with ultrasonic pulse-echo technique, reflection spectrum analysis was introduced to evaluate TiAl and 40Cr diffusion bonding quality. Frequency dependence of reflection coefficient was used to distinguish perfect bonding from imperfect bonding. It is found that the reflection coefficient from perfect bonding interface does not vary with frequency. When the size of imperfections is much smaller than the wavelength of ultrasound, the reflection coeffwient depends on frequency. When the size of imperfections is the same order of or even larger than the wavelength of ultrasound, the reflection coeffwient does not exhibit frequency dependence. However the amplitude of imperfect interface is higher than the amplitude of perfect bonding interface. A combination of reflection spectrum analysis and ultrasonic pulse-echo technique provides more accurate information about the bonding quality of dissimilar materials.     

焊接理论：一般问题

铝合金脉冲GTAW熔池表面反射模型的建立；大电流钨极氲-氦混合气体电弧行为分析；材料的焊接性对焊接质量及焊接成本的影响；铝合金脉冲MIG焊熔宽动态过程的视觉传感辨识；焊接性的数学分析——报告题目。     

反射熔炼铝废料时垂直喷枪的应用

反射熔炼铝废料时垂直喷枪的应用［俄罗斯］Ｂ．１１．ｙｋｏＢ等薛文林译范靖亚校目前，在使用石油液化气（ＣＩＩГ）为能源的再生有色金属冶炼企业中，有５０％以上的铝废料是在反射炉中进行再生处理的￣［１］，这种较普遍采用的方法是以熔炼大块头铝及其合金废料并有...     

哈密金矿小型反射型焙烧炉的应用实践

小型反射型焙烧炉对含碳金精矿焙烧处理量为1．2～1．5t／d，投资少，总造价1万元，焙烧后进炭浆系统，金总回收率达90%．     

基于插件技术的试题多样化解决方案和实现

针对在线外语学习平台中试题展示的需要, 研究了插件的基本思想, 将插件的思想应用到试题的设计过程中, 提出了一种基于插件的试题设计与展现方法, 并在ASP.NET MVC环境下给出了具体的设计与实现, 并将此方法应用到易立方智能化外语学习平台中. 实践证明该方法能够很好的解决题型多样化问题, 为当前在线学习平台的设计提供了一定的参考价值.