横截面

Based on the analytical theory of aeolotropy,thermal distortion and temperature field distributions of Nd∶YVO4 crystal with rectangular section were investigated when the third thermal boundary condition was considerated.

以各向异性半解析热分析理论为基础，研究矩形横截面Nd∶YVO4激光晶体在有第三类热边界条件工作时，激光晶体温度场分布和晶体抽运面热形变分布。

The basic approach of protecting people from being hurt or killed in an accident is to improve crashworthiness of vehicles. This paper starts with discussing theories and methods for vehicle passive safety design, which included experiential methods, analytic methods, multi-body dynamics methods, crash test methods and the finite element method. Emphasis will be paid to the basic FEM theories and algorithms of impact problems. Topics discussed include the governing equation, element discretization, hourglass control, time integration, material model, shell element algorithms and contact-impact algorithms. For more reliable simulation results, this paper then conducts study on how to accurately get material model parameters by combining the FEM method with experimental method, and develops relevant material test machine and parameter calculating software. Based on that, basic typical impact simulation and test validation study are conducted. On the basis of the above work, the paper studies the thin-shell structures'crashworthiness, which was affected by the following factors: spot-weld features, shell thickness, cross-section and pre-deformation. As to vehicle parts'crashworthiness, the paper conducts simulation study of designing energy-absorbing steering system and adaptive airbag system. A practical energy-absorbing steering wheel is designed as an example. In further depth research, the paper suggests several inverse quantificational methods for vehicle crashworthiness design based on the ideal crash characteristics. The above theories and methods are applied with good results through several practical vehicles' crashworthiness design and improvement.

文中对汽车碰撞安全性的设计理论和方法进行了归类和总结，其中包括经验法、解析法、多刚体动力学法、试验法以及有限元方法等；重点介绍了碰撞有限元法的基本理论和有关算法，涉及到有限元求解控制方程、单元离散、沙漏模态控制、时间积分、材料模型和应力修正、薄壳单元算法以及接触碰撞界面算法等，探讨了有限元计算中的材料模型参数获取技术，开发了相应的材料试验装置及材料模型参数反求软件，在此基础上进行了基本的碰撞仿真算例和试验对比研究；文中通过应用有限元方法研究了薄壁构件的碰撞吸能特性，指出了设计薄壁吸能构件时需要考虑的几个主要影响因素，即焊点、壁厚、横截面和预变形等；在关于车辆部件的碰撞安全性能设计中进行了吸能转向机构和自适应安全气囊的仿真研究，提出了吸能转向机构和自适应安全气囊的仿真研究方法；文中最后探讨了整车碰撞性能的设计与改进方法，提出了以理想碰撞特性为目标，采用分段加速度或者根据碰撞时间进行设计的反推设计法、部件吸能仿真优化设计法等量化设计方法，并通过综合应用文中所讨论的相关技术进行了整车碰撞性能的设计与改进实例研究，所选定的车型是大众化的普通轿车和碰撞安全性基础较差的微型面包车，研究结果表明，本文所提出的设计与改进方法是适用而有效的，具有重要的工程实用意义和价值。

From energy balance equation, using micro-piece analytical method, heat balance equation for high power fast axial flow CO〓 laser tube is established with the boundary conditions of actual fast axial CO〓 laser, the analyzed solution of the temperature distribution in the laser tube is obtained.

并应用热传导的物理边界条件，求出了热能平衡方程的解析解，得到了实际器件放电管横截面内的气体温度分布公式及温度分布曲线，并求得了激光功率变化对热致负透镜焦距的影响关系式。

Some Andalusite crystals have carbonaceous inclusions, arranged so that in cross-section they form a dark cross.

某些红柱石晶体含有碳质包裹体，正是这种结构导致了她的横截面有一个黑十字。

If the shaft seal bad back, there will be large number of resin powder leaked, each class should be pressed for several Pan-gen still leakage phenomenon not only affects the sanitation, and increase the volume of maintenance and therefore a need to use The system forms a seal 4 gear is reasonable Screw conveyor is the use of motor driven rotary screw, the passage of materials in order to achieve the purpose of transportation machinery, it can level, tilt or vertical transmission, a simple structure, small cross sectional area, sealing, and easy to operate, easy maintenance, facilitate closure transportation and other advantages.

如果轴后端密封不好，就会有大量树脂粉泄漏，每个班要压好几次盘根，仍有泄漏现象，既影响了环境卫生，又增加了维修量，因此急需选用一种适用于该系统的密封形式 4传动装置的合理性螺旋输送机是利用电机带动螺旋回转，推移物料以实现输送目的的机械，它能水平、倾斜或垂直输送，具有结构简单、横截面积小、密封性好、操作方便、维修容易、便于封闭运输等优点。

Recently, barrettes have been used widely all over the world. A lot of researches carried out on their vertically-loaded behaviour, especially in influence of their non-axisymmetrical cross-section on it. But all these methods are implicit methods, which needs a lot of computing time. So in order to improve the understanding the vertically-loaded or lateral-loaded behaviour of barrette behaviour further, preliminary researches on barrettes are carried out in this paper.

近年来，随着壁板桩的广泛应用，相关研究也在逐步展开，有关其竖直承载特性方面的研究也在逐渐展开，尤其在壁板桩横截面非轴对称性对承载特性的影响方面也取得了很大的进展，但是这些方法多为三维隐式分析方法，需要耗费大量计算时间和内存。

Meanwhile, the variation of the cross-section in width and height has significant effect on the distribution of the moment and the deflection of the beam and on the displacement and the velocity of the mass.

同时，横截面宽度和高度的变化对简支梁上弯矩分布、挠度分布、刚性质量块的位移和速度都产生了明显的影响。

In addition, to the simple beams with equal sectional area but different sectional shape, the distribution of the moment and the deflection of the beam and on the displacement and the velocity of the mass are different.

另外，轴向上同一位置处，横截面面积相等而形状不同的梁，其弯矩分布、挠度分布、刚性质量块的位移和速度均产生了较明显的变化。

The shear and bending moment of beam cross-section were calculated by the internal function of Excel.

根据Excel的内置函数求梁在横截面上的剪力和弯矩。

Based on the harmonic algorithm, the conductivity reconstruction method and the corresponding algorithm in oblique slice were proposed. Then the numerical simulation was performed by solving the Neumann boundary problem, Ohm's law and Biot-Savart law to obtain the magnetic flux density used to reconstruct the conductivity.

然后通过数值仿真来实现提出的算法，首先进行了正问题求解，即利用Neumann边界值问题、欧姆定律和毕奥－萨伐尔定律逐步计算出重建电导率分布的磁通密度的一个分量，接着进行了逆问题求解，即根据重建算法得到了横截面和斜位面内的相对电导率分布，并对仿真的结果进行了分析和讨论。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。