查询词典 inverse element

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 the second chapter, elementary theories and ideas of one step forming inverse approach were described and warped modification method, implemented by Cook, was introduced into one step forming simulation and based on idea of surface spreading; new quadrilateral element modification arithmetic was put forward. By spreading warped quadrilateral onto plane in local coordinate system, a plane quadrilateral element whose shape and area were equal to original warped quadrilateral element was gotten and internal force vectors of four nodes and stiffness matrix of elements were improved to increase precision of simulations on this plane element.

第二章从一步成形逆有限元法的基本理论和思想出发，将Cook基于弹性理论的四边形单元的翘曲修正算法引入基于塑性的一步成形，并且基于曲面展开的思想，本文提出一种新的四节点单元翘曲修正方案，通过把翘曲的单元展开的方法在局部参考系中得到一个与实际翘曲单元的形状与面积非常接近的平面单元，在该平面单元中进行单元刚度及内力向量的计算，进一步改善模拟结果的精度。

The operation laws including:commutative law, associative law, cancellation law, unity of operation, inverse element, and distributive law between two operations,here we just omit them.

这些运算律包括：交换律，结合律，消去律，运算单位元，运算逆元，两个运算之间的分配律等，在此不再一一说明详细过程。

This scheme is more efficient by avoiding the calculation of inverse element over the field Z.

该方案避免了Z中的求逆运算，从而提高了效率，并且通过对该方案的详细安全性分析，证明了它是安全的。

In the third chapter, the finite element inverse approach has been applied to an L-shaped cup drawing simulation. Compared with the experimental result and incremental FEM result, the numerical results of inverse approach validate the efficiency and accuracy of inverse approach. In the fourth chapter, a rear fender has been chosen to be an example of 3D complicated auto panel.

采用有限元逆算法数值模拟了L-形方盒件的冲压成形过程，计算结果与试验结果及增量有限元结果进行了比较分析，结果表明：有限元逆算法结果与试验结果基本吻合，而且有较高的精度，在产品初期设计阶段具有较大的应用价值。

The S box was constituted with the multiplication inverse element affined transformation in GF(2) of all elements of limited field GF(28),with S box s nonlinear byte changed,ciphered text attained the ideal status of the even of difference and the linear of deviation,and increased the capability of the AES algorithm of anti beating the difference cipher of analysis and linear cipher of analysis.

S盒由有限域G F(28)上所有元素的乘法逆元及在域G F(2)上的仿射变换构成，经过S盒的非线性字节代换，密文的差分均匀性和线性偏差都达到较理想的状态，提高了A E S算法抗击差分密码分析及线性密码分析的能力。

This paper systematically provides an overview of recent developments in small punch test technology including empirical and computational methods for determining elasto-plastic parameters from the measured data of small punch test. The computational methods involve finite element and parameter method, inverse finite element procedure, finite element and inverse methodology, inverse identification based on artificial neural networks, finite element optimization, shape deformation and hybrid inverse procedure et al.

本文系统综述小冲杆试验的测量技术及从测量数据来确定材料弹塑性参数的各种经验方法和计算方法，例如有限元分析和参数法、反向有限元法、有限元和反方法、反向识别和人工神经网络、有限元优化和试验变形形状以及杂交反方法等。

This paper is generaly devided into three parts,The first prepare knowledge,introduceing some conceptions asssociated with the polynomial ring and ring of power series such as power-zero element,inverse element and primitive polynomia and so on,prepare to introduce characters of power series.

本文主要分为以下三部分：首先介绍与环、多项式环、幂级数环密切相关的一些概念，如幂零元、可逆元、本原多项式等，为接下来介绍幂级数环的定义及其性质做下铺垫；然后着重讨论了环的性质，加深对多项式环与幂级数环的理解；最后讨论了多项式的性质，并将这些性质推广到幂级数环中，这也是本文的重点所在。

The inverse polynomial and the invertible affine transformation exist by the finite field, linear algebra and matrix theory. The invertible affine transformation and the inversion in are easily realized by using lookup table. An algorithm can be used to get the inverse element of modulo .

本文运用有限域、线性代数和矩阵理论，论证了逆多项式和逆仿射的存在性，并且应用查表法简捷地实现了中元素的求逆和逆仿射变换；设计了一个易于在在计算机上实现的算法，来求形如的多项式模时的逆元，该多项式的系数在上。

In our study,two important lepidopteron pests,beet armyworm and cotton bollworm were surveyed for their endogenous piggyBac.As a result,endogenous piggyBac elements were found in these two insects,and one of the piggyBac elements isolated from the genome of cotton bollworm was intact and thought to be potentially active.1 Clonging and sequence analysis of piggyBac from beet armywormUsing PCR technique,with degenerate primers,a DNA fragment of piggyBac-like element was cloned from the genome of beet armyworm,spodoptera exigua hubner.The DNA fragment was 456bp in length,and the deduced amino acid sequence shares 50%- 78% similarity with other piggyBac elements from insects.But one stop code was found in this DNA fragment.

由于转座子很难用常规的RT-PCR和RACE技术进行克隆鉴定，故本研究在兼并引物PCR的基础上，利用inverse PCR和vectorret PCR技术，不仅调查了鳞翅目两种重要的农业害虫甜菜夜蛾和棉铃虫的內源piggyBac存在情况，同时克隆到了內源性的piggyBac转座子，并且从棉铃虫中获得了一个结构完整、具有潜在活性的piggyBac转座子HaPLE1.1甜菜夜蛾piggyBac转座子基因的克隆与序列分析采用PCR技术，利用兼并引物，从甜菜夜蛾基因组中克隆出一个內源性piggyBac类似因子的DNA片段，并命名为SePLE。

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。