细分曲面切片轮廓线的Lifting小波变换

基于Lifting小波变换原理对细分曲面实体切片操作产生的离散交点序列进行处理,将它们组织为属于多个层次结构的多分辨率曲线。用4种不同的Lifting小波变换进行了多分辨率曲线的构造实验,并对产生的多分辨率曲线进行了对比,讨论分析了这些Lifting变换方法的性能特点。     

正压法在立式拱顶油罐变形修复中的应用

分析了一例常压拱顶油罐罐顶失稳的原因 ,介绍了拱顶油罐注水补压修复方法。为了保证设备的安全 ,对壳 顶节点的强度及罐体提升力进行了校核 ,并分析了外界环境和注水量对罐内压力的影响 ,对处理类似问题有一定的参考价值     

基于反求工程的机械产品方案设计

反求工程是一种现代快速设计方法，方案设计是机械产品设计的关键。文中提出了基于反求工程的机械产品方案设计的基本思路和设计要点。     

Manual handling performance: the effects of menstrual cycle phase

Physiological and subjective responses to physical performance have been shown to interrelate with fluctuations in the female hormonal environment throughout the menstrual cycle. The aim of this study was to examine whether these fluctuations affect the strenuous performance required in manual handling. Seventeen eumenorrheic females performed lifting tasks in five phases of their menstrual cycle. These tasks were maximal isometric lifting strength (MILS) and an endurance lift at 45% MILS (t), at both knee and waist height; and the selection of a maximal acceptable load (MAL) to lift six times per min, for 10 min, in both the sagittal and asymmetric planes. Heart rate response (HR) and rating of perceived exertion (RPE) were recorded throughout each of the lifting tasks. MILS, t and the chosen MAL were unaffected by menstrual phase over both heights and planes of lift (p>0.05). HR to the isometric endurance lift was greater following ovulation than prior to ovulation by ? 7 beats.min^?1 (p> 0.05). This was true when the data were analysed at 50, 80 and 100% of the time to volitional fatigue, and by an area under the curve procedure. HR to the dynamic lifting tasks was also elevated by ? 7 beats.min^?1 following ovulation. This difference was non-significant due to the low power of the analysis. Re-analysis of the data by re-sampling 1000 matched comparisons produced significant phase variations (p> 0.05). The RPE for all of the lifting tasks was independent of menstrual phase (p> 0.05). The impact of the eumenorrheic menstrual cycle on lifting capability was negligible in the present study. However, the results of this study indicate that all further investigations utilizing HR data to produce recommendations for health and safety in manual handling tasks must control for menstrual cycle phase in female populations.     

On the Convergence of a Spline Method for Singular Two Point Boundary Value Problems Arising in Physiology

The second order spline method developed by Iyengar et al. [11] for the problems $$\eqalign{ x^{-\alpha}(x^\alpha y^\prime)^\prime & = f(x,y),\quad 0     

70MN液压机横梁机加工翻身用吊耳设计研究

针对70MN液压机三大梁钢板焊接加工特点,通过类比法开发设计了用于机加工翻身用吊耳装置,并通过理论分析和有限元仿真计算,对其设计强度进行校核验证,最终满足设计使用要求。     

薄壁大平板铸件的反重力充型数值模拟

Sola-VOF方法是目前进行铸件充型模拟的主流方法。用VOF方法捕捉自由表面，难以施加自由表面条件。采用守恒标量法将气液两相作为同一相来计算，从根本上克服了VOF方法所遇到的计算困难。而守恒标量法在处理气／液界面时存在着两相参数跃迁的难题。针对守恒标量法格式的特点，对相应的Simple格式进行了重构，从而解决了上述问题。根据以上原理，用反重力充填大平板的水力模拟试验作了验证计算，计算结果与试验结果基本符合。     

重型扬矿管主动升沉补偿系统的设计与仿真研究

本文设计了一种采用电液比例方向阀控制的重型扬矿管主动升沉补偿系统，利用SIMULINK和功率键合图建立了升沉补偿系统的仿真模型，对系统的静动态特性进行了仿真研究，分析了其对控制策略的要求。     

移动式天气雷达系统改装设计中的若干问题

介绍了移动式天气雷达系统的改装设计方案,对系统的布局、双摇杆机构的杆件长度、升降装置的载荷与工作原理、减振架和减振平台的结构、立位转台的调节、工程车的改装等问题作了分析,给出了系统结构的主要参数和一些有实用价值的计算结果。     

A new symbolic representation method to support conceptual design of mechatronic system

Regarding the typical mechatronic system that realizes controlled motion behaviour as the research object, the mechatronic system is composed of three subsystems, they are generalized executive mechanism subsystem, sensing and testing subsystem, and information processing and control subsystem. Based on the three subsystems, a new kind of symbolic representation method to represent a design scheme of mechatronic system is presented. This symbolic representation method includes graphical symbols, literal symbols and port information flows on the abstract layer of basic mechatronic function units in common use. Two applied instances are given. The method standardizes scheme representation of mechatronic system. The purpose is that the computer can identify and operate the standardized scheme representation. Furthermore, the method can be implemented in connection with related knowledge base to produce creative scheme. The symbolic representation method provides theoretical basis for computer aided conceptual design of mechatronic system.