基于残留高度控制的椭球面铣削螺旋刀轨

针对光学领域的高精度椭球面加工,文章提出了使用基于残留高度控制的螺旋刀具轨迹加工椭球面的方法。推导出了椭球面与球面之间的几何关系,提出了用NX UG软件快速进行椭球面建模的方法;对椭球面的残余高度进行分析,得出了椭球面球刀加工的残留高度及刀轨行距的近似计算公式;推导出了包络椭球面的螺旋线的参数方程,利用NX UG软件建立了包络椭球面的螺旋线,并根据残留高度要求确定螺旋线的圈数;通过实例验证了通过生成的螺旋线驱动生成刀具轨迹,进行仿真后,结果满足理论粗糙度的要求。     

型腔高速铣削加工刀具轨迹优化研究

本文详细介绍了型腔高速铣削加工的常见方法,指出了各自方法的特点,并阐述了当前型腔高速加工中拐角加工残余的产生和去除以及刀具轨迹优化的策略。     

鼓风机扭叶转子的数控加工轨迹研究

以鼓风机扭叶转子的端面曲线方程为基础,采用截面铣削法,首先求出扭叶转子螺旋曲面方程,再由扭叶转子螺旋曲面的法向等距面推导出球头铣刀中心在x—y平面上的轨迹曲线,并实例验证所求轨迹的可行性。     

基于MasterCAM的数控铣削加工刀具路径优化

通过作图比较,研究了不同尺寸刀具的切削粗糙度要求对刀具轨迹的影响,又进一步通过对曲面特征细分进行研究,并举例说明了如何利用MasterCAM的虚拟仿真技术和自动编程技术,以实现数控铣削加工刀具路径优化。     

高速铣削残留高度对加工表面粗糙度的影响

针对球头铣刀高速铣削表面残留高度的数学模型,提出了控制表面粗糙度的主要途径,并通过实验研究获得了行间距、进给速度、切削速度对高速铣削铝合金表面粗糙度的影响规律,对优化切削参数,改善零件表面质量具有重要意义.     

复杂车削类零件数控加工刀具轨迹分析

分析了基于华中Ⅰ型数控系统的数控车床加工曲线回转类零件的几种编程方法，研究了该类零件的各种数控编程方法的优缺点，提出了该类零件数控编程的合理方案。     

汽车同步器齿套加工刀具设计及切削参数的优化

本文分析了汽车同步器齿套滑块槽的加工现状,提出了采用飞刀摆线加工同步器齿套滑块槽的新方法,设计了专用切削刀具.为了延长刀具使用寿命、提高切削效率,介绍了采用单因素法进行切削参数的优化实验,并根据实验结果选出了最佳的切削参数.     

模具型腔高效加工的分片轨迹规划研究

为了实现模具型腔的高效数控加工,提出了一种基于切削带宽方向分区的轨迹规划方法.该方法先将参数曲面进行离散,然后求出各离散点的任意切削带宽方向与带宽大小的关系函数;在UV参数图上表示出此点在取得最大切削带宽条件下的带宽方向,并对离散点的带宽方向进行聚类划分;分片后,根据切削带宽的方向对各分片区内首条加工轨迹进行优化;进而使用等残留高度轨迹规划方法,生成模具型腔精加工的刀具轨迹.仿真证明,该方法能有效地提高加工效率.     

数控车床多刀具加工时刀具偏差的校正方法

分析了直接对刀法进行数控车加工的缺陷，介绍了用样件试车法进行多刀具加工的刀偏补偿方法，以满足实际生产中对产品加工精度的要求．     

数控编程中刀具半径补偿的应用技巧

刀具半径补偿指令是加工中心和数控铣床上一个常用的应用指令,实际使用中经常出现程序校验错误或补偿后的运动轨迹异常等现象.本文以铣削加工为例,详细分析了刀具半径补偿指令在数控铣床编程中的使用技巧.     

刀具路径规划在数控铣削加工中的应用

比较了不同的切削模式和参数对数控铣削加工的影响.利用UG NX模拟了某型飞机加强角材冲压凹模的数控铣削加工过程,对生成的刀具轨迹路径进行了比较分析,得到了优化路径.     

空间相关的多点多维地震动合成方法

基于谱方法的随机场理论,借助功率谱密度函数来描述地震动随机场,同时考虑不同点、不同向地震动分量间的相关性,分别采用Clough-Penzien模型和屈铁军-王君杰相干模型来描述平稳自功率谱和平稳互功率谱,建立了空间相关的多点多维地震动合成方法。采用Matlab R2010b编制生成程序,并以某445m大跨度拱桥场地条件为例,生成空间相关的多点多维地震动时域样本,并将该时域样本的功率谱密度函数与目标功率谱密度函数进行对比。结果表明:模拟结果与目标值吻合较好,按照上述方法生成的多点多维地震时域样本满足要求。     

Varying paths for learning to revise

The paper draws on the Vygotskyan view of instruction, advocating the support of learners within their individual Zones of Proximal Development. It describes an instructional design developed iteratively—gradually building in scaffolding techniques to support the use of the procedural facilitation of text evaluation during revision—and the open-ended management of its provision to students, so that they could fade it out themselves.The study took place in a writing class for students at basic writing levels. The present, post hoc analysis is concerned with individual differences among three members of the class identified as weak, intermediate and more advanced novices while learning to revise within that program.     

Case study evaluation of an intervention planning tool to support emotional well-being and behaviour in schools

Questions of how best to support both children’s emotional well-being and behaviour in schools are pervasive. The efficacy of an intervention planning tool to support internalising and externalising emotional needs and promote early intervention was explored in a small-scale case study. Adults were trained in two primary schools to carry out the intervention planning tool which they did with a total of 12 children. The intervention planning tool was based on principles of multi-element plans (MEPS) and target-monitoring and evaluation (TME). Data from scaling (TME), the Strengths and Difficulties Questionnaire, a questionnaire based on the School Children’s Happiness Inventory (SCHI), and interviews with school staff and children were analysed using statistical and thematic analyses. Findings indicated that the intervention planning tool supported positive outcomes overall for the children, and that while some barriers were identified, several unexpected advantages were also revealed.     

Development of a virtual tool for learning basic organisation and planning in rural engineering projects

This paper presents a virtual lab for the contents of an Engineering project, for designing an agro-industrial building, which is also useful for a range of different transversal courses in Engineering sciences. The aims of this tool are to analyse the most important contents of a project-document (calculation, regulations, drawings and budgets), as well as their relationship with the activities which make up the work and the schedule. The design criteria we considered were: its online applications and their compatibility with Moodle; the inclusion of different learning approaches, such as exploratory learning and inquiry-based learning; its interactivity, and the use of multimedia elements for visualisation and direct analysis on material common to Engineering subjects. The students’ perceptions of the improvements brought by the virtual lab were analysed statistically through a series of questions over two academic years. The results of the questionnaires suggested that most of those who had used the e-learning tool valued positively its overall suitability for reaching the objectives in their subject as well as the way it improved the working methodology. The practical knowledge acquired by the students was also highly valued. In addition, the lack of constraints commonly related to field trips (expenses, time and complexity) illustrates the utility of self-access learning tools in key transversal disciplines such as Engineering projects.     

大学生职业生涯规划课体验式教学法初探

当前,高校毕业生的就业率和就业质量是评估高校人才培养质量的重要指标之一,大学生职业生涯规划课已成为各高校的必修课程,授课教师在课程模块及教学模式方面都进行了相当多的探索。不足之处是对如何提升课堂教学效果的创新相对较少。文章重点探讨了大学生职业生涯规划现有教学模式的不足,论述了体验式教学的内涵,进而提出创新大学生职业生涯规划课程教学模式的着力点。     

Solutions to Efficient Provision of Accommodations for Universities in China

Chinese universities are facing a series of challenges in their accommodations,of which a pr\edominant one is how to provide both students and staff with enough accommodations of a large scope and good quality in good time and with limited budgets,In order to find applicable approaches to solve this problem,the current situations of the Chinese higher education reform and the resulted rapid growth of student numbers whereby the requirement of lodgings is greatly incresed are discussed.It is elucidated that in providing enough accommodations for staff and students,Chinese universities are confronted with difficulties including demand too big,lack of funding support,time limitation and incapability in both project management and facilities management.Industrialized building approach is demonstrated to be a desirable access to build large quantities of accommodations of good quality in limited time.and Private Fuinancial Initiative(PFI) appears to be a prosperous solution to the fund shortage,Regarding project and facilities management,qualified professionals are available by either employing exterior consultants or training related staff of universities for such occupations.