参数方程

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。

Through the analytical solutions of momentum differential equation for a stream with varying mass, a general characteristic parameter , depending on structure scale and flow parameter, is introduced.

在径向流体分布器的变质量动量方程理论模型的基础上，通过对模型解析解的分析，获得了包括径向分布器结构尺寸和流动参数的特征参数k／C。

Part Two. The approximation theory of distributed parameter systems.

偏微分方程的特征函数理论是研究分布参数系统的一个有效方法，但分布参数系统的特征函数的求取十分困难。

Sur . This model was used to simulate the experimental data of lipase-catalyzed hydrolysis of olive oil in AOT/isooctane reversed micelles. The model parameters were obtained and the model equation was in good agreement with the experimental data.

利用该模型方程对AOT／异辛烷反胶团中脂酶催化橄榄油水解的动力学数据进行拟合，得出了模型参数，模型方程与实验结果吻合较好。

It was presented that a dynamic retrieving differential equation mode of two-variable hydrologic time series considering one main cycle.

3提出一种考虑一个主周期的水文二元时间序列动力反演微分方程模式，并应用双向差分法和最小二乘法推导微分方程参数，给出求解公式。

Methodological analysis is based on pulse wave to conduct the principle of blood pressure of time computation artery, put forward pulse wave to conduct the relation equation of time and blood pressure, discussed method of equation parameter demarcate.

方法分析基于脉搏波传导时间计算动脉血压的原理，提出脉搏波传导时间和血压的关系方程，并论述了方程参数标定方法。

On the basis of propulsive model,a mathematical model which is used to describe the motion of pitching and heaving of dolphin's caudal fin by ways of coordinate transformation is deduced.Meanwhile,this model can show the relationship between the motion of caudal fin and parameters related,then the motion of caudal fin of dolphin is simulated by the software of Matlab which showed the swimming principle.

以海豚背腹式摆动推进方程为基础，应用坐标变换的方法，建立了描述海豚尾鳍俯仰－沉浮运动的数学模型，同时建立了描述豚尾各运动参数之间关系的方程，随后运用Matlab的仿真功能再现了海豚在游动过程中尾鳍的运动规律。

In the description, the fluid lump and the precursor film are calculated as a whole using order parameter coupled Navier-Stokes equations, CHW (Cahn, Hilliard and van der Waales) equation and GNBC (Generalized Navier boundary condition).

流体团和先驱膜作为一个整体用与组分序参数耦合的Navier-Stokes方程， CHW(Cahn， Hilliard， van der Waales)方程和GNBC(广义Navier边界条件)进行数值模拟和分析。

By using the Nernst equation and measured electromotive force data,the corresponding mean activity coefficients of KI and interaction parameters were obtained.The weak association of KI in methanol was discussed.

研究较多的是利用离子选择性电极与电解质溶液组成无液接电池，测定对某一电解质响应的电动势数据，由此从电动势出发可以关联得到电解质溶液活度系数的Pitzer方程或其它方程的参数，进而得到电解质溶液的活度系数[1]。

The parameters were obtained by fitting the experimental data to a modified Langmuir equation.

使用修正的Langmuir方程对吸附等温线进行关联，计算出Langmuir方程参数。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。