基于三维CAD软件的快速成型制造技术及其精度控制

快速成型制造技术能将Pro/E软件设计的三维实体零件快速地制作成零件或者模具。采用STL转换格式进行Pro/E软件与快速成型软件数据对接,通过控制曲面到三角面片的弦高差来控制成型精度。     

可靠性分析方法在矿山边坡中应用研究

比较了矿山边坡可靠分析方法与传统的定数分析方法, 认为可靠性分析方法明显优于定数分析方法。概括地说明了可靠性分析方法的优点、原理及其几种主要分析方法, 进而介绍了该方法的分析程序, 最后以一矿山露天采矿小型边坡实例简单说明了可靠性分析方法的分析过程。     

大型活动屋顶行走系统的设计分析

对大型体育场活动屋盖的行走机构方案进行分析讨论,提出3种可行的行走结构,初步建立结构的选择原则,在此基础上确定适应实际需要满足经济性要求的结构方案。     

某矿似层状顶板支护技术研究

为了确定某矿似层状顶板的支护方式，首先通过了解该矿顶板围岩的工程地质、围岩的基本特征，分析该矿似层状顶板的冒落机理，得出了似层状顶板的一般破坏模式。再将该矿的矿岩稳定性与工程实际相结合，计算合理的采场结构参数，并利用控制爆破技术，最大限度保护似层状顶板的完整性。最后通过几种不同支护方式的分析比较，结合似层状顶板在工程中的特征，确定了该矿似层状顶板的支护方式为长锚索支护。长锚索支护方式可以改变似层状顶板支护安全性结构，提高该类型顶板支护结构的整体性和承载能力。目前，这种支护方法已经在该矿逐步推广应用，同时针对目前顶板管理的现状，总结了矿山顶板管理存在的问题，制定了合理有效的顶板管理制度，提高了采矿作业的安全性。     

一阶脉冲微分方程无穷边值问题

运用Krasnosel′skii′s不动点定理,研究了无穷区间上一阶脉冲微分方程边值问题解的存在条件,得到了解的存在准则,并给出了实例。     

网络百科全书现状分析与应用研究

目前,网络百科全书被越来越多的人所接受。文章根据对网络百科全书现状的研究以及与传统百科全书的对比,分析了网络百科全书的优势与缺陷,并对网络百科全书未来的发展提出了有建设性的建议。     

A study on the electro-oxidation and electropolymerization of a new OPE linear molecule by EQCM and in situ FTIR spectroelectrochemistry

A novel symmetric conjugated oligo(phenylene-ethynylene) (OPE) linear molecule (1,4-bis(4-aminophenylethynyl)benzene); BAB) was synthesized by Sonogashira cross-coupling reactions. The structure and purity of the compound were confirmed by ¹H NMR, ¹³C NMR and infrared (IR) and mass spectrometry (MS). The electrochemical oxidation process and mechanism of BAB were investigated via in situ Fourier transform infrared (FTIR) spectroelectrochemistry and electrochemical quartz crystal microbalance (EQCM). The electrochemical oxidation mechanism of BAB was proposed. The studies revealed that the BAB concentration and oxidation potential had a significant influence on the growth of the polymer film. A densely packed polymer film, which exhibited nonelectroactivity, was formed when a high monomer concentration and a high oxidation potential were used. When the electropolymerization of BAB was conducted at a lower concentration, a new pair of redox peaks appeared, and the resultant thin film had better electroactivity. The in situ FTIR studies confirmed that BAB could be electro-oxidized into radical cations and then electropolymerized via para (N-N) and/or ortho (N-C) coupling reactions to form polymers with a larger conjugated π-electron system. The surface morphology of the poly-BAB was also investigated with atomic force microscopy (AFM) and scanning electron microscopy (SEM).     

高职网页设计与制作课程教学的几点改进

网页设计与制作是一门实践性很强的课程,该文主要根据高职院校学生实际情况并结合本人实际教学经验,从教学目标、教学对象、教学内容、教学方法等几个方面阐述如何改进本课程的教学,并探讨如何培养学生的实际动手能力。     

高职信息安全专业课程体系改革与实践

高职院校课程体系建设应坚持以就业为导向、以能力为本位、以课程整合为手段等基本原则。本文从信息安全岗位群出发,分析专业职业目标、职业能力与学习领域之间的关系,提出我院信息安全专业课程体系建设的解决方案,并在课程体系设置中尽量做到知识、能力、素质三个层次不脱节。     

Comparison of empirical and semi-empirical calculation methods for venting of gas explosions

Venting is a widely applied method to protect process equipment from being destroyed by internal explosions. The key problem in venting is the appropriate design of the vent area necessary for an effective release of the material. For gas explosions different calculation methods exist, but there are no clear recommendations which one should be preferred for the practical cases under consideration. The present paper gives a review of different calculation methods, their ranges of validity, their physical background and applicability. The presented examples include a comparison of computed reduced explosion pressures for methane–air, propane–air and hydrogen–air mixtures with experimental data and two fictitious test cases. The results of different methods show a wide range of scatter, however some recommendations for their applicability can be given.