用于超高真空的磁力耦合传动元件工作特性的研究

本文介绍了用于超高真空设备中的磁力耦合传动元件的工作原理与结构，以及与普通磁力传动的差别。利用集总参数法建立了磁路参数计算的数学模型和公式，并得出传动力和力矩的计算公式。针对一种实用元件画出其工作特性曲线。这些内容是指导磁力传动元件优化设计和合理选用的理论其础。     

超磁致伸缩换能器磁力耦合固有特性分析

建立了超磁致伸缩换能器弹性支撑连续体磁力耦合模型,从第一类压磁方程出发,利用简化后得出的轴向压磁方程,建立了超磁致伸缩换能器的磁力耦合波动方程,在静态磁场下对换能器的磁力耦合固有特性进行了理论分析,初步确立了超磁致伸缩换能器的磁力耦合固有频率,并与一般连续体纵向振动固有频率进行了分析比较.     

磁感应式磁力传动器及其性能实验研究

对真空机器人用磁感应式磁力传动器进行了建模,对其磁路和机械本体部分进行了设计.根据结构尺寸要求和已有各参数间的影响关系,确定磁路的关键参数.利用集总参数法建立转矩计算模型,将得到的关键参数代入其中进行计算.搭建动态性能测试平台,对其动态转矩特性进行测试,将结果与理论设计值比较,得到本磁力传动器的动态性能特点:低频涡流损...     

真空电弧熔炼快冷制粉装置

介绍了真空电弧熔炼快冷制粉装置以及两个重点结构—水冷双电极和磁力耦合装置     

随机振动加载条件下焊点形态参数对板级光互连模块对准偏移影响分析

建立了光互连模块有限元分析模型并进行随机振动加载有限元分析,获取了垂直腔面发射激光器(Vertical Cavity Surface Emitting Laser,VCSEL)与耦合元件间的对准偏移;采用水平正交表设计了不同焊点结构参数组合并建立有限元模型,获取了对准偏移数据并进行方差分析。结果表明:在随机振动加载后,光互连模块VCSEL与耦合元件间会产生水平、垂直、轴向的偏移;陶瓷基板焊点高度、VCSEL焊点高度对对准偏移具有高度显著性影响;因素显著性排序由大到小依次为:陶瓷基板焊点高度、VCSEL焊点高度、陶瓷基板焊点体积和VCSEL焊点体积;单因子分析表明VCSEL与耦合元件对准偏移值随陶瓷基板焊点高度增加而增大,随VCSEL焊点高度增加而增大。     

橡胶悬置元件结构参数优化设计方法

由于橡胶悬置元件的结构比较复杂,截面不规则,无法用传统的优化方法对其结构优化.利用遗传算法和神经网络相结合的策略对橡胶悬置元件的几何结构参数进行优化,即用神经网络学习算法建立橡胶悬置元件几何结构参数与其三个方向刚度的非线性全局映射关系,获得遗传算法求解结构优化问题所需的目标函数,用遗传算法进行优胜劣汰的寻优搜索运算,求出最优解.优化结果表明,橡胶悬置元件结构参数优化设计方法是可行的.     

基于有限元的异步电机电磁振动分析

电机的电磁振动是电机电磁场与机械结构耦合的结果,要研究电机的电磁振动,需要将电机的电磁场和结构振动分析结合起来。通过有限元软件,采用一种弱磁-固耦合的方法,对异步电机的电磁振动特性进行分析。首先利用ANSOFT有限元软件建立异步电机的二维有限元模型,计算电机的瞬态电磁场,得到电机在给定转速稳态运行状态下的磁场分布和作用在定子上时变的电磁力;其次用ANSYS有限元软件建立异步电机结构的三维有限元模型,将ANSOFT软件得到的时变电磁力进行频谱分析并校正,然后施加到电机上,计算出电机结构的电磁振动响应。基于对电机电磁振动特性的分析,可以对电机的电磁参数和结构进行改进和优化设计,以降低电机的电磁振动     

桁架结构系统静强度与疲劳的耦合可靠性分析

根据结构可靠性分析理论和疲劳载荷对结构造成的损伤,建立了元件静强度和疲劳耦合可靠性分析的失效判别准则,给出了元件静强度失效时所对应的当量寿命,分析了元件静强度失效和疲劳失效之间的相互影响,进而讨论了结构系统静强度和疲劳的耦合可靠性分析方法。算例表明:在不同的使用年限内,静强度失效和疲劳失效对结构系统失效的贡献是不同的;在结构系统主要失效路径中既有元件静强度失效又有元件疲劳失效;若只考虑单一因素(或静强度、或疲劳)下的可靠性分析,可能会导致结构不安全。     

多源激励下浮筏隔振系统导纳功率流研究

建立了浮筏隔振系统的振子力学统计分析模型，使用导纳功率流的方法研究了隔振系统的振动响应和振动功率流特性，并通过数值方法分析了筏体和隔振器参数变化对传递到基础结构功率流的影响。分析结果表明：增大基础厚度、减小系统中耦合元件的耦合刚度和增大筏体质量可以有效控制系统的传递功率流。     

基于动力学模型与参数优化的ISD悬架结构设计及性能分析

为寻找结构简单、性能优越的悬架结构(Inerter-Spring-Damper,ISD),对储能元件、支撑元件及耗能元件按不同位置构建21种工程上可行的拓扑结构,建立通用动力学模型。以簧上质量加速度及轮胎动载为目标进行优化,获得每种结构的元件参数。与传统悬架对比发现有12种新型结构性能优于传统悬架。对典型结构分析表明,动力学建模与参数优化方法在ISD悬架设计中具有一般性、通用性。     

VRC－3200型薄绝缘环氧树脂真空浇注设备及工艺研究

本文简述了一种在干式变压器生产中具有重要意义的设备——ＶＲＣ－３２００型环氧树脂真空浇注设备。结合各个部分的作用及相应的工艺参数，介绍了整套设备的工作原理及结构特点     

微孔塑料物理发泡新技术

微孔塑料因其独特的结构性能和工艺合于环保要求而成为研究热点忧核过程和泡孔长大的控制是微孔发泡中的研究重点。文章阐述了泡核形成的均相成核,固液界面诱导的非均相成核以及空穴成核的机理和模型。在成核过程中,泡核的临界半径和成核速率占用 位,提高体系的过饱和度和压力降有利于泡核临界半径的减小和成核速率的提高。     

太阳能真空集热管排气台的设计

本文介绍了太阳能真空集热管气台的设计要求与结构特点。     

三工位片式钽电容器真空预烧炉的研制

介绍了三工位片式钽电容器真空预烧炉的基本结构、工作原理及钽电容器阳极块真空预烧的工艺过程,并对该设备在片式钽电容器制造行业的意义进行了阐述。     

Effect of manual and digital contact tracing on COVID-19 outbreaks: a study on empirical contact data

Non-pharmaceutical interventions are crucial to mitigate the COVID-19 pandemic and contain re-emergence phenomena. Targeted measures such as case isolation and contact tracing can alleviate the societal cost of lock-downs by containing the spread where and when it occurs. To assess the relative and combined impact of manual contact tracing (MCT) and digital (app-based) contact tracing, we feed a compartmental model for COVID-19 with high-resolution datasets describing contacts between individuals in several contexts. We show that the benefit (epidemic size reduction) is generically linear in the fraction of contacts recalled during MCT and quadratic in the app adoption, with no threshold effect. The cost (number of quarantines) versus benefit curve has a characteristic parabolic shape, independent of the type of tracing, with a potentially high benefit and low cost if app adoption and MCT efficiency are high enough. Benefits are higher and the cost lower if the epidemic reproductive number is lower, showing the importance of combining tracing with additional mitigation measures. The observed phenomenology is qualitatively robust across datasets and parameters. We moreover obtain analytically similar results on simplified models.     

大时差双倒向爆破拆除七层空心砖混结构楼

待拆七层公寓楼房为空心砖墙和钢筋混凝土构造柱结构 ,具有较小的高宽比。爆前通过预处理 ,切断南、北楼的联系 ,使它们成为独立的建筑物。采用大时差多段别延时爆破方案 ,使两个独立的楼房分别向南、北方向倒塌。文中论述了爆破方案设计、爆破参数确定以及在空心砖墙上进行钻孔和装药的施工工艺。     

高台阶崩落法处理复合采空区的应用实践

采用深孔牙轮钻机、利用高台阶崩落法成功地处理了复合采空区,解决了复合采空区处理难的问题,使技术人员在熟练浅采、深采空区处理的情况下,又探索出复合采空区的处理方法。为矿山的发展消除了安全隐患,扫清了前进的障碍;为同类矿山的空区处理及相关问题的探讨提供了参考依据。     

MCT的概念及其在工厂管理中的应用

介绍了生产制造击期的概念及其计算方法，讨论了在工厂管理中如何应用ＭＣＴ。     

A three-constituent multicontinuum theory for woven fabric composite materials

Multicontinuum theory (MCT) refers to the use of phase averaged constituent stress/strain fields for predicting failure in composite structural analysis. Given the composite material mechanical properties as well as those of the constituents, well known closed form algebraic expressions exist to decompose the composite stress/strain fields down to the constituent level. Recent research indicates constituent based failure algorithms show a great deal of promise in predicting material failure when coupled to nonlinear finite element codes. A limitation of MCT is that the traditional constituent decomposition is only valid for materials composed of two constituents. In this paper, the MCT decomposition is generalized to handle composite materials composed of three constituents. The application of interest is a woven fabric composite material. The three constituents consist of the warp bundles, fill bundles, and pure matrix pockets. Numerical results are presented for the proposed three-constituent decomposition and are shown to be in good agreement with phase averaged stresses obtained from direct volume averaging of finite element micromechanics models.     

“Vitamin E” fortified parenteral lipid emulsions: Plackett–Burman screening of primary process and composition parameters

The objective of this study was to screen the effect of eight formulations and process parameters on the physical attributes and stability of “Vitamin E”-rich parenteral lipid emulsions. Screening was performed using a 12-run, 8-factor, 2-level Plackett–Burman design. This design was employed to construct polynomial equations that identified the magnitude and direction of the linear effect of homogenization pressure, number of homogenization cycles, primary and secondary emulsifiers, pre-homogenization temperature, oil loading, and ratio of vitamin E to medium-chain triglycerides (MCT) in the oil phase on particle size, polydispersity index, short-term stability, and outlet temperature of manufactured emulsions. The viscosity of vitamin E was reduced from 3700 (100%) to 64 mPa.s (30%) by MCT addition. As viscosity is critical for efficient emulsification, vitamin/MCT ratio was the most significant contributor for the stability of emulsions. Particle size increased from 236 to 388 nm, and percentage vitamin remaining emulsified after 48 h dropped from 100 to 73% with increase in vitamin/MCT ratio from 30/70 to 70/30. Significant decrease in particle size and PI, and an increase in outlet temperature were also observed with increase in homogenization pressure and number of homogenization cycles. Emulsifiers and oil loading, however, had insignificant effect on the responses. Overall, stable submicron emulsions at vitamin/MCT ratio of 30/70 could be prepared at 25,000 psi and 25 cycles in ambient conditions. The identification of these parameters by a well-constructed design demonstrated the utility of screening studies in the “Quality by Design” approach to pharmaceutical product development.