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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。

In this paper we use pointwise modulus of smoothness to study approximation direct theorem and equivalent theorem for some linear operators and quasi-interpolant operators; Using pointwise modulus we discuss the strong converse inequality on K-functional; and using a modified weighted K-functional and weighted modulus of smoothness we study approximation with Jacobi weight on operator with non-zero first order moments.

本文利用点态光滑模ω_~(2r)来研究某些线性算子及逆中插式逼近正定理和等价定理；利用点态光滑模讨论其关于K-泛函的强逆不等式；同时利用一种改变的带权K-泛函和带权光滑模研究一阶矩不为零的算子的点态带Jacobi权逼近。

According to the demand of high magnetic field power supply, reference is increased with a set ramp rate and stops at a set stable value, so reference system is composed of digital setting and digit to analog converting circuit. But the stability of reference is mostly guaranteed by the performance of D/A circuit, so D/A circuit is particularly studied in reference system. The scheme of D/A circuit, the selection of DAC and its voltage reference, hardware anti-jamming design and PCB design are discussed in detail, and software of remote control and PLC are discussed in brief. Zero-flux DC current transformer well satisfies the demands of the high stability of Load current detection unit, so the principle of zero-flux DC current transformer is analyzed; in the mean time a project which detects the long term stability is designed. During 8 hours, analog signal which is detected with high precision digit multimeter is recorded in computer at 1HZ frequency by GPIB communication. The drift error source and related parameters are explained in the compare-amplify part. Detailed subtraction circuit is designed; also amplifier chip and periphery components are selected and verified according to the theory of error analysis.

根据强磁场电源的需求，参考源应按照软件设定的斜率逐渐上升到设定稳态值，则参考源系统应由数字给定和数模转换电路两大部分组成，而参考源的稳定度主要依靠完成数模转换功能的模拟电路的性能来保证，因此本文对参考源系统的研究以数模转换电路为重点，分别从电路方案的确定、数模转换芯片及其基准电压源的选取和验证、电路板硬件抗干扰和PCB设计几方面进行了论述，然后对数字给定部分的远控组态和PLC程序设计作了简要介绍；采用零磁通原理的直流电流转换器很好地满足了对负载电流检测单元高稳定度的需求，本文详细分析了零磁通检测的原理，并在选定此种类型电流转换器的基础上设计了一套检测长期稳定度的方案，8小时内以1秒为采样周期，通过计算机Labview程序和高精度数字电压表的GPIB通讯，将被高精度数字电压表数字化后的模拟信号采样值连续记录至计算机中；比较放大环节简要阐述了漂移产生的原因和相关参数指标，确定了具体的减法电路形式，并根据误差分析理论对运算放大器和外围元器件进行了选取和验证。

The results also show that the module of state vector is more sensitive than other parameters stat...

研究结果还表明，相对于态矢量增量的模、态矢量方向的改变等参量，态矢量的模在震前的变化更为敏感，此外，对于相同震级的地震，最佳扫描区域尺度大小不一，并对这些现象进行了一定的解释。

The results shown that, for the typical kind of photonic crystal fibers with hexagonally arrayed circular air holes, the band gap of acoustic wave of XY mode appears only when the air holes' filling rate is greater than certain threshold value, and the upper and lower boundary values of the band gap decrease with the increasing of the air holes' filling rate.

结果表明，对于较为常见的空气孔排列为六角密排结构、空气孔形状为圆形的实芯光子晶体光纤，只有当空气孔的填充率大于一定阈值时才出现较明显的XY模态声波的带隙，并且最低与次低带隙的上下边界均随空气孔的填充率的增大而下降。

In the second chapter, we introduce the definition of pointwise convex modulus. The relation between numbers of pointwise convex modulus and relevant geometric properties will be discussed. we research the characteristics of numbers of pointwise convex modulus .

在本文第二部分引入了点态凸性模的定义，并讨论了点态凸性模的取值与相关几何性质之间的关系，研究了点态凸性模取值特点。

Firstly, the high resolution pictures of dragonfly wings from sample tests were studied thoroughly, and the unique feature of the reticulate vein distribution and the variation of the vein sizes and the grid shapes in different zones were figured out;then several computational models based on a dragonfly wing were established by using ANSYS, and beam 189 and shell 93 elements were used respectively in modeling of the veins and the membrane so as to ensure the compatibility between the veins and the membrane at a deformed state;these models subject to uniform loading cases were analyzed respectively so as to explore the unique performances of the wing structure, furthermore, through eigenvalue spectrum analyses of these models, the special role of the pterostigma in eliminating or suppressing the wing quivering effect was also evaluated.

首先，对实验中获取的高清晰度的蜻蜓翅膀数码图片进行了细致地分析，找出了翅膀网状翅脉结构中翅脉的分布规律与尺寸变化、网格形状的差异及不同形状网格的分布等独特的结构特征；再利用ANSYS建立蜻蜒翅膀网状翅脉结构模型，采用三节点等参数梁元beam189模拟翅脉和八节点等参数曲壳单元shell93模拟翅膜，以满足翅脉和翅膜间的变形协调性要求；通过非线性数值分析，探索了蜻蜓翅膀网状翅脉结构在均布荷载作用下所具有的独特的结构性能；通过模态分析，揭示了翅膀前缘靠近翼尖附近的翅痣在翅膀消震减振中所发挥的作用。

Thus he listed Aristotle's system in four groups of three: quantity (universal, particular, singular), quality (affirmative, negative, infinite), relation (categorical, hypothetical, disjunctive) and modality (problematic, assertoric, apodeictic).

因此，康德以四个三元组列出了亚里斯多德的体系：量（普遍的、特殊的、具体的），质（肯定的、否定的、无限的），关系（绝对的、假设的、选言的），模态（或然的、实然的、必然的）。

Thus he listed A ristotle's system in four groups of three: quantity (universal, particular, singular), q uality (affirmative, negative, infinite), relation (categorical, hypothetical, disjunctive) and modality (problematic, assertoric, apodeictic).

因此，康德以四个三元组列出了亚里斯多德的体系：量(普遍的，特殊的，具体的)，质(肯定的，否定的，无限的)，关系(绝对的，假设的，选言的)，模态(或然的，实然的，必然的)。

By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the reson...

通过用正弦波形模拟桥面的不平和考虑移动车辆-桥梁间的相互作用，在Euler＿Bernoulli梁理论的基础上建立了一种车桥系统的耦合振动模型·利用模态分析法和Runge＿Kutta法对模型进行数值求解，获得了车桥系统耦合振动的动态响应和共振曲线·发现车桥耦合振动的共振曲线中存在两个共振区域，一个反映主共振而另一个反映次共振·讨论了桥面不平、桥梁振型和车辆间的相互作用对系统振动的影响·数值结果表明，这些参数对系统振动的影响很大，桥面不平和振型对车桥系统耦合振动的影响不能忽略，设计车速应该远离临界车速

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。