结构函数

In this thesis,based on the DFT+NEGF first-principles method,we construct a lead-molecule-lead sandwich system with single benzene-based molecule to investigate the relationship between the structure and properties of the molecular devices and the factors that influence properties of the molecular devices.Our computational investigations on these molecular devices are primarily concentrated on the effect of contact geometry between molecules and electrodes,the effect of side groups,the effect of different torsion angle between two phenyl rings and the effect of external electric field.This thesis consists of five chapters:In Chapter one,we mainly introduce the research background and development of the molecular electronics,including the experimental fabrication of molecular electronic components and theoretical simulation methods.Afterwards we discuss the questions that need to be solved in this area.Finally,the main contents of this thesis are listed.In Chapter two,we introduce the theoretical methods used in this thesis, including the main first-principles calculation methods,i.e.,the Density-Functionmethod and nonequilibrium Green\'s function.

本论文拟采用密度泛函理论和非平衡格林函数相结合的第一性原理计算方法，选取苯基小分子作为研究对象，构建了金属电极/有机小分子/金属电极三明治结构体系，系统地研究了苯基分子器件结构的改变与分子电输运性质之间的关系以及影响分子器件电输运性质的相关因素，其中重点研究了分子与电极间可能的接触结构改变、官能团、分子间的扭转角以及外电场对苯基分子电输运性质的影响，本论文主要包括以下五个章节的内容：第一章为综述部分，主要介绍了分子电子学产生的背景、分子器件的研究意义、当前研究分子器件的实验和主要理论方法，以及目前在研究分子器件中存在的一些问题，最后给出了本论文的主要研究内容和技术路线。

Based on the analysis of the mechanism of robot manipulators, a trajectory tracking controlling research model is first built up with ADAMS, and its mathematical model is formulated through the study of robot kinematics and dynamics. After the modeling errors are analyzed in practical robotic systems, a conception of centralized error is brought forward according to the theory of weighting functions. In the case of modeling errors' exist, the robotic uncertain model is derived by introducing an auxiliary control variable into inverse dynamic analysis. The control strategy of robust exponential convergence is applied to the robotic uncertain model, the applicable conditions and the applicable controller with this application are presented. The stable control effect under three main model uncertainties (parametric errors, joint disturbs, joint frictions) are systematically studied on the previously built research model. The problems of robust exponential convergence controller which often results in unstable output and so produces a large relative error when the input trajectory is in a small range are resolved by adjusting the control parameters based on the controller's structure.

本文在机械手的机械结构分析基础上，利用ADAMS建立了用于机械手轨线跟踪控制研究的机械手模型；通过对机器人运动学和动力学问题的研究，建立了机械手研究的数学模型；分析了机器人系统中模型误差的主要来源，根据加权函数法分析，提出了模型集中误差的概念；在存有模型误差的情况下，采用逆动力学结构并引入辅助控制量，由机器人误差模型推导了机器人非确定性模型；提出了采用鲁棒指数收敛法对上述机器人非确定性模型进行鲁棒镇定的控制策略，并给出了对机器人进行鲁棒指数收敛控制时系统不确定因素应满足的匹配条件；针对机械手研究模型，深入研究了鲁棒指数收敛控制器对机器人系统中常见的模型参数误差、关节扰动、关节摩擦等不确定因素的镇定控制效果；针对鲁棒指数收敛控制器易产生控制量振荡的问题以及在小范围内系统轨线跟踪的稳态误差过大问题，本文分别提出了基于控制器结构的控制参数调整法和基于轨线跟踪范围大小的控制参数分段切换法。

Based on the analysis of the single-ring resonator, both the transfer functions of parallel-coupled structure and the ones of series-parallel structure in multiple-ring high order resonators are derived using the transfer matrix method. And the influences of the length of straight waveguide between rings, coupling coefficients between rings, coupling coefficient between straight waveguides and ring, the number of rings and the radii of rings on spectral response are also analyzed. Spectral response at drop channel with maximally flat response pass bands and sharper roll-off could be achieved by optimizing these parameters, so as to improve the performance of output spectral response.

在分析单环结构的基础上，利用传输矩阵法，推导了多环并联和多环串联两种耦合结构的高阶谐振器的传输函数公式，分别分析了并联环间直波导的长度、串联环间耦合系数、环与直波导间的耦合系数、环个数和环半径对相应结构输出特性的影响，通过优化这些参数实现下话路输出光谱具有通带的最大平坦性和过渡带良好的滚降特性，从而达到改善其输出光谱特性的目的。

Concretely speaking, using the irreducible tensor theory, we deuced the formulism for fine-structure energies of boron-like atoms in the ground and first excited states, which involves spin-orbit, spin-spin and spin-other-orbit interactions; completing all the angular integrations and spin summations needed, we make the final expression for fine-structure energies of boron-like atoms in the ground and first excited states in a combination of radial integrations. Afterwards, employing the wave functions we got in Chapter Three, we accomplished all the radial integrations and so obtained the fine-structure energies.

具体地说，利用不可约张量理论导出了类硼离子基态以及第一激发态的精细结构的表达式，给出了自旋-轨道、自旋-自旋、自旋-其它轨道相互作用等所涉及的所有角向积分和自旋求和的解析计算方法，完成了角向积分、自旋求和的计算，使类硼离子基态以及第一激发态精细结构能级最终可以表示为径向积分之和；在此基础上利用以前所得到的非相对论性波函数，进一步完成了所有径向积分的计算，从而得到了对应能级的精细结构的理论计算值。

Half penalty method and optimism design of ten connecting bar mechanism of plunger slide in double action drawing press;2. The essential boundary condition is imposed by employing a penalty method .

将选择施加在"虚结构"控制点上的虚载荷作为形状优化的设计变量，并将它与无网格Galerkin法相结合来开展结构形状优化研究，采用罚函数法来施加边界条件，通过直接微分法建立了结构形状优化的离散型灵敏度分析算法，利用无网格法研究了节点坐标关于设计变量导数的计算。

The grain boundary energy, as a function of the excess volume △V, is closely related to the crystalline structure for the same element.

分别采用普适状态方程和准谐德拜近似对Co的fcc与hcp结构和Fe的fcc与bcc结构的界面能进行了计算，结果表明同一种元素不同结构的界面能有差异，它们的界面能是过剩体积△V的函数。

In order to compute the failure probability of structural systems for stability of gravity retaining walls, firstly, two performance functions against overturning and sliding of gravity retaining walls were established. Then, the first order second moment theory in structural reliability analysis, i.e., the checking point method was introduced to compute the two failure modes respectively, and two corresponding reliability indexes could be obtained.

为了计算重力式挡土墙稳定性的结构体系失效概率，首先分别建立重力式挡土墙结构抗倾覆稳定性和抗滑移稳定性的功能函数，然后引入结构可靠度分析一次二阶矩法中的验算点法分别对两种失效模式进行计算，得出两个相应的可靠度指标。

Molecular dynamics simulation was carried out to study transformation pseudoelasticity in NiAl alloy with a initial B2 structure, using EAM type interatomic potential for NiAl.

利用NiAl合金的嵌入原子势，进行了B2结构NiAl单晶中相变伪弹性的分子动力学模拟模拟过程中系统的径向分布函数和键连线原子分布图的变化表明，在外加拉应力的作用下，B2结构的奥氏体向L10结构的马氏体转变，马氏体在长大过程中发生了变体间的转化与合并，不同取向的变体之间由于自协调效应形成共格的孪晶界面。

Using the Mindlin theory, the four-node finite element shell modal of healthy and damaged structure is formed; Using Green Function theory, the fluid around the structure is considered to be inviscid, irrotational and incompressible, and then the effect of fluid to structure is translated to the added mass matrix compared with global mass matrix using BEM.

基于Mindlin理论，本文建立了描述健康和损伤的四结点有限元板壳单元模型；基于Green函数理论，将结构所处的流体环境考虑为无粘、无旋、不可压缩的理想流体，推导了三维问题拉普拉斯方程的基本解，并利用边界元方法将流体对结构的影响归结为对结构整体质量矩阵的影响；针对各向同性损伤单元，采取刚度各向整体弱化的方法分析；对于各向异性损伤单元，采用Kachanov理论，引入了x和y两个方向的弹性损伤折减系数。

In order to characterize the spatial characteristics at different scale, different theoretical model coefficient we defined to create the Kriging map and the rational number of sampling impendent from each other at different spatial scale.

变异函数结构分析显示，土壤机械组成的空间变异在各方向上具有不同变率，但均可通过线性变换而转换为各向同性的统一结构，属于几何各向异性结构；不同观测尺度上有着不同的空间结构特征，对不同空间结构的区域化变量确定了不同的理论模型参数，并绘制克立格图，给出不同观测尺度下满足独立取样的合理取样数目。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。