可调倾角非球面加工夹具仿真软件的设计

对可调倾角非球面加工夹具进行运动学分析,确定工作台转角与电机转角之间的关系,以及工件坐标系原点相对于基坐标系的位置向量.使用VC++6.0作为编程开发平台,结合开放性图形库(OpenGL)技术,将3D Studio(3DS)模型导入VC环境中,并正确地显示出模型.在此基础上对夹具的各部分进行分别的控制,进而实现可倾角夹具的仿真.此外,用Matlab进行图像处理,然后利用VC与Matlab的混合编程,在VC中调用计算结果.     

一种简单可靠的数控加工工装夹具设计

工装夹具在实际生产中至关重要,它不仅影响加工的质量和精度,同样影响着加工的效率。在实际工作中,结合生产需求,设计一款结构简单可靠、稳定的工装夹具,合理的利用加工中心工作台面,达到降低工装装夹时间、定位精度、提高生产效率、减少对加工中心机床台面的摩擦为目的,并在实际生产中批量推广使用,获得的积极的反响。     

小型非球面超精密加工建模及控制技术研究

根据高精度小型非球面制造的需要,探讨了一种针对小型非球面元件的加工方法,并分析了实现数控加工控制的技术途径.根据非球面加工理论,基于工控机和Windows系统,用VB.NET开发实现了小型非球面数控加工控制软件.     

加工中心高效加工模式研究

通过夹具的创新设计,充分利用加工中心的工作台面,一次更换刀具后连续加工一组零件,以减少换刀时间、空刀行走时间、开关门时间,降低加工中心的非创效时间,增加人机分离程度,实现加工中心高效加工、一人多机的目的。     

工-夹系统刚度计算及变形加工误差模型

研究切削加工过程中工件-夹具系统的刚度计算方法及变形加工误差.运用经典Hertz接触理论和有限元方法,基于切削加工中工件的准静态受力分析,提出工件-夹具系统刚度计算的新方法,建立了基于工件-夹具系统刚度的工件加工误差预报模型.该方法避免了有限元计算中接触分析的使用,无需多次非线性迭代计算,减少了计算时间.     

基于最小材料去除量的比较球面计算与仿真

基于非球面最接近球面的计算方法分析,构建成型设备与工件间坐标变换矩阵,借鉴并优化材料去除量最小原则,计算最接近球面与理论非球面间的偏离量,建立数学模型.针对典型的圆形口径和矩形口径同轴、离轴非球面元件的比较球面求解进行仿真.结果表明,所建立的数值求解模型可有效计算同轴、离轴非球面元件的比较球面使材料去除量最小,对加工实践起到指导作用.     

可转位连杆加工夹具设计

机械加工中夹具设计对零件加工质量和生产效率有至关重要的作用.针对连杆加工中存在的问题,通过误差分析,设计了可转位连杆加工夹具.分析了定位、夹紧和转动过程.该设计可提高连杆加工生产效率.     

推动架及其加工夹具的设计

推动架及其加工夹具的设计主要有两方面的内容,主要有机械加工和夹具设计两个部分,论文从机械加工工艺、加工方法、工艺路线、刀具的选择和夹具设计等方面进行探讨,本论文的应用分析着重于从B6065刨床出发,根据被加工零件的特点,来制定推动架及其加工夹具的设计工作,保证加工工作的高效、经济,保证工作稳定可靠。     

影响非球面面形精度的因素分析

根据国内外非球面零件加工难的现状,其根本原因在于多数非球面光学零件很难找到可作为加工依据的准确轨迹,同时也很难找到使轨迹在加工过程中精确转移的方法.而且在加工中,保证面形精度也是最难的问题.本论文主要就非球面面形精度进行探讨.根据等距线公式建立了数学模型,得出保证加工精度时对截取参数选择的方法.     

回转工作台台面参数化设计与稳态分析

介绍了一种利用Pro/E的参数化技术功能对回转工作台台面进行参数化建模的方法,大大提高了回转工作台台面设计的效率,缩短台面工艺结构的开发周期,提高设计质量.由于回转工作台的台面在运动过程中受力情况相当复杂,利用ANSYS10.0对Pro/E的参数化台面模型进行稳态分析.为产品的预评价、生产加工提供了重要依据.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Editorial note for the special topic on ＂Nanopore Analysis＂

The concept of nanopore analysis, using the pore-forming protein a-hemolysin to detect individual nucleic acids at a single-molecule level, was first proposed in 1996. Over the past two decades, tremendous progress has been made in the nanopore field, and nanopore analysis has become a label-free and high-throughput method for probing bio- molecules and other analytes with single-molecule sensi- tivity, especially holds the promising for ＂third generation＂ DNA sequencing. However, challenges still remain in the experimental strategies and the design of whole nanopore-based instruments. Here, we proudly present a special topic dedicated to the topic of ＂Nanopore Analysis＂, with 8 reviews/articles providing up to date coverage of the experimental strategies, theoretical calcu- lations and simulations, and instrument design. Reviews and articles on the experimental strategies cover control of DNA partitioning into a nanopore, detection of target DNA, and the advantages of nanopore-based DNA sequencing. The theoretical calculations and simulations discuss the translocation behavior of DNA, and an inte- grated measurement system and data analysis software are presented for instrument design.     

Effects of climate change on biodiversity

1 Rise of studies on climate change＇s effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America＇s annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].     

Discussing the Expansive Learning in Modern Organizations

<正>1 Introduction Endeavours on learning methods have long occupied the mind spaces of scholars and there have been theories abound on how people learn and in what way organisations can use some of the knowledge gained in the art of learning to maximise human productivity.While the theories by themselves are not solutions to problems,they are steps of inquiry that provide us with interesting perspectives that we can use to extend our knowledge of the dimensions of learning.This paper is an exploratory work on the theories postulated by three notable scholars including Zimmerman     

Progress in Linear Scaling Non-Orthogonal Localized Molecular Orbitals Method

The non-orthogonal localized molecular orbital(NOLMO)is the most localized representation of electronic degrees of freedom.As such,NOLMOs are thus potentially the most efficient for linear scaling calculations of electronic structures for large systems.However,direct ab initio calculations with NOLMO have not been fully implemented and widely used,partly because of the slow convergence issue in the optimization of NOLMO.We devel-     

An Accurate and Universal HEOM Approach to Strongly Correlated Quantum Impurity Systems

A hierarchical equations of motion(HEOM)approach is developed for general open quantum systems coupled to fermionic environment.The HEOM method is in principle formally exact,as it resolves nonperturbatively the combined effects of many-body interaction,system-bath dissipation,and non-Markovian memory.In practice,the HEOM approach is highly accurate and efficient for the characterization of strongly correlated quantum impurity sys-     

关于有理混合吸引子的Ciric型非唯一不动点定理

本文我们应用有理混合吸引子条件去证明具非唯一不动点的映射Ciric型的若干不动点定理.结果推广并改进已知的一些结果.     

次线性算子交换子在变指数Herz-Morrey空间上的有界性

本文主要利用给出的次线性算子分别与BMO函数及Lipschitz函数生成的交换子在变指数L~(p(·))(R~n)空间上的有界性,证明了其在变指数Herz-Morrey空间MK_(q,p(·))~α~((·)),λ(R~n)上的有界性.     

利用GPS双频观测值实现PPP电离层延迟高阶项改正

给出了利用双频观测值计算L3组合电离层延迟高阶项改正的方法,并与全球电离层延迟文件的改正效果进行对比.利用赤道附近的15个国际全球卫星导航定位系统服务组织(IGS)站的数据进行比较,结果表明:2种方法计算的电离层二阶项延迟互差最大不超过1 cm,三阶项延迟互差最大不超过5 mm;电离层高阶项改正后的观测值精密单点定位(PPP)解算结果N、E、U方向互差平均值分别为0.4、0.5、1.0mm,因此2种改正方法效果在同一水平.