机械CAD技术研究进展与开源软件应用介绍

为进一步推广开源的机械CAD软件,本文概述了CAD技术研究现状与发展趋势及软件开发情况,梳理并挑选出6款机械CAD应用方面较为流行且功能全面的开源软件,包括Libre CAD^;、Python CAD;、Python CAD^;、Sag CAD;、Sag CAD^;、QCAD;、QCAD^;、Free CAD;、Free CAD^;和SALOME;和SALOME^;。1通过综述逐一介绍各软件技术特色、功能特点、界面风格、使用经验和开发历史等,以期有助于更多的机械工程技术和研究人员了解和使用这些软件,推动CAD技术及开源软件应用发展。     

基于AcDb数据库的有限元程序及其后处理

介绍了基于CAD系统的有限元软件的特点 ,并以开发可视化的岩土工程有限元分析程序 (VGeoFea)为例 ,说明了将有限元分析与CAD系统相结合的方法 .最后 ,通过该程序的后处理的实现 ,表明了将有限元分析向CAD系统内部集成是实现科学计算可视化的有效手段 .     

互联网环境下的暖通CAD组件模块的开发方法研究

针对单机环境下暖通CAD软件重复开发量大、开发周期长等现状，提出了基于互联网环境的三层体系结构及其开发的通用环境，即整个暖通CAD系统被分为不同逻辑块，开发和管理的工作向服务器方转移，从而使分布处理数据成为可能，基于组件的软件开发是互联网环境中应用软件的主要开发方式，以构架为组装蓝图，以可重用组件为组装预制块，支持组装式软件重用，从而克服人力和物力的浪费，进而为了重用暖通CAD已开发出的功能模块，给出组件逆向工程的开发方法、组装流程和组件管理过程。     

产品开发中计算机辅助设计软件的组合运用

主要讨论了在现代新产品设计和开发中，将几个CAD软件组合运用，即针对不同产品特点或产品开发不同阶段使用不同功能的CAD软件，而非使用单一的CAD软件，从而充分发挥CAD软件及设计人员的各自优势，达到提高产品开发效率，减少设计错误的目的。还以一款手机产品设计为例，介绍多种软件的相互配合使用，实现高效开发的过程。     

基于MFC与OpenGL的可视化机械仿真设计系统

通用可视化机械设计系统对硬件要求高,其仿真运动模拟一般不响应定量数据输入.为此,本文研究了一种对硬件要求低且运动仿真模拟能实时响应定量数据输入的机械设计系统.该系统基于微软基础类库(MFC)与开放图形库(OpenGL)以及科学计算软件而开发.开发实例表明:相较于大型CAD软件,该系统具有更为快速的绘制功能,对于不同精度条件下的零件数据都能够计算并予以可视化显示.该设计系统能够实现机械零件的快速设计和开发.同时给出了对心尖顶直动从动件盘形凸轮机构可视化系统开发实例.     

MATLAB在数字图像处理教学中的应用

数字图像处理是电子信息专业高年级学生的一门专业课程,其教学特点是如何利用计算机来完成图像的处理,这必然要求学生熟练掌握一门计算机编程语言来实现课程中的算法。MATLAB作为一款强大的科学计算软件,易学易用,而且自身有大量的工具箱函数可供调用,大大降低了程序编写和调试的难度,非常适合在教学科研中使用。     

PDF文档表格信息的识别与提取

为编辑PDF文档中的表格信息，设计一种基于Python平台的，包含文件选取与文件转换两大功能模块的信息提取软件。该软件利用Python内置库，针对PDF中不同表格的结构设计算法，识别表格内的文字信息与表格结构,将得到的表格结构还原至Word与Excel文档中,文字信息同样复原至对应单元格内。实验表明:开发的软件完整快速地提取了PDF中的表格信息，并将其转化为易于编辑的Excel和Word文档，达到了预期目的；其转换速度与收费软件WPS相当，转换速度明显快于其他免费转换软件；识别精确度与迅捷PDF转换器、Smallpdf等相比有所提高。     

集成电路版图CAD系统的数据结构方法

本文在引进美国Gould公司Coneept32/2750小型计算机CAD系统开发交互式集成电路版图CAD软件中,介绍一种建立版图数据结构及其管理方法。对图形实行数字化,文件化,提高了图形编辑效率。为设计LSI版图CAD系统软件提供了一个有效的图形文件化手段。     

机制专业CAD教学模式的思考

通过分析部分CAD软件特点及其应用，提出利用三维造型原理，重点讲解CAD软件建模的共性知识；结合学生的毕业去向，支持学生有针对性地学习相关CAD软件；根据就业需要，采用教学、自学与培训共存，鼓励学生考证；并对教师在学生学习与使用CAD软件过程中的主导作用做了阐述。     

基于I-deas的工装CAD系统中知识库系统的研究

论述了基于三维建模软件I-deas的工装CAD系统中工装知识库系统的结构、功能及其子库实现方法，分析了子库之间的相互关系。以开发的工装设计管理系统中工装知识库系统开发为例，描述了知识库系统与工装设计管理系统的集成。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that