查询词典 analytic geometry

We think that the coupling dynamical modeling offlexible multibody system should be established on continuum mediummechanics and analytic dynamics and making the coupling dynamicalmechanism between large overall motions and deformation motions clear.

本文认为柔性多体系统刚-柔耦合动力学建模应从连续介质力学和分析动力学出发，合理地描述柔性体的变形运动，才能探明大范围运动和变形运动之间的耦合动力学机理。

The nanostructures and mechanical properties of nanocrystalline Ni with average grain size ranging from 2.09nm to 5.23nm were simulated with analytic embedded-atom method and Molecular Dynamics.

摘 要：运用分子动力学技术，结合分析型嵌入原子方法模拟计算了平均晶粒尺寸为2.09~5.23nm的纳米多晶Ni的微观结构和力学性能。

Keywords Nanocrystalline;Analytic embedded-atom method;Molecular dynamics;Microstructure;Grain boundary;Mechanical properties

Article From 湖南大学；材料物理与化学硕士论文 2004年度纳米晶体；分析型嵌入原子方法；分子动力学；微观结构；晶界；力学性能

The types of Subei basin, the structural features of main abundant hydrocarbons depressions, the features and genetic mechanisms of structural trap assemblages and the characters of oil-gas distribution are chiefly studied in this work with applying comparative structural geology, analytic structural geology and Earth dynamics, the control of the structure on oil-gas is generalized, and then the exploration targets were found based on these analysis.

综合运用比较构造学、解析构造学和地球动力学等方法，重点研究了苏北盆地成因类型、主要富烃凹陷构造特征、构造圈闭组合特征和成因、油气分布特征，总结了构造对油气分布的控制作用，在此基础上寻找有利的勘探方向。

Using the Newton-Euler approach, the whole complex analytic dynamics equations considering the base link and two leg's 12 links are derived. Based on the complete dynamics model, the reactive force/moment by the ground could be computed in the simulation.

先利用牛顿-尤拉法推导出含躯干和双足之完整解析动力学方程式，由完整解析动力学模式可以计算动态行走过程中，机器人与地面接触所产生的地面反作用力/力矩。

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 addition, this paper gives the analytic expression of space posit...

给出了采用关节式测头架的测量机的数学模型

The characteristic equation of the beam is derived, as well as an analytic expression of its eigenfunction.

推导了此梁弯曲振动的频率方程及振型函数的解析表达式。

Besides, the multinomial analytic expression of the intensity is get.

此外，给出了散射光分布的多项式解析表达。

The analytic expression of its stacking line is deduced.

推导了其积迭线的解析表达式。

The receding calculations and experiment analyses in this subject are built on the blood cast of pig tongue.

本研究课题的前期工作是采用猪舌血管铸型模拟人舌而进行的数值计算与实验分析。

"Each human infection constitutes an opportunity for genetic modification of the virus through reassortment, mutation, or both...."

&每一次人类的感染都暗藏着一次基因修改的机会，无论是通过病毒的整合、突变或者兼而有之。。。。&