电脑系统快速备份与恢复的几种方法

计算机系统及信息数据非常重要.熟练掌握系统的备份与恢复,可以减少重新安装带来的麻烦,尽快恢复原有的系统和软件及驱动设置.为此对Windows 2000和Windows XP操作系统下的数据备份和恢复功能进行了阐述,给出了针对整个系统进行的镜像(GHOST)备份和恢复的方法,并以实例形式分析了各种备份、恢复策略及适用场合.     

屏蔽门玻璃的选用及有限元分析

介绍了钢化玻璃的性能及其自爆的原因,提出了地铁屏蔽门玻璃的安全选用建议,通过对钢化玻璃的相关参数进行分析,得到了玻璃厚度的最优解,为屏蔽门系统的设计及防护提供相关依据。     

基于齿轮时变啮合刚度的转炉倾动机构固有特性研究

在分析倾动机构结构特点的基础上,应用分析力学理论建立了某厂300t炼钢转炉全悬挂倾动机构的12自由度扭振动力学模型;对其耳轴悬挂大齿轮和与之啮合小齿轮的时变啮合刚度进行了二次抛物线拟合和计算分析,得到啮合刚度的变化曲线;在考虑时变啮合刚度的情况下计算了系统的固有频率。结果表明,系统固有频率发生时变,且与时变啮合刚度具有相同的变化趋势;时变啮合刚度对系统高阶固有频率影响较大,对分析系统高频段异常振动与故障诊断具有积极意义。     

Thermo-mechanical-martensitic Transformation Numerical Simulation of High Strength Steel in Hot Forming

在已建立的高强度钢板热成形热、力、相变多场耦合本构模型和板料、水冷模具相互耦合的接触热传导模型基础上,基于自主开发的商业化金属成形CAE软件KMAS(King-Mesh analysis system)构建热成形热、力、相变耦合的非线性、大变形静力显式数值模拟模块.对典型U形高强度钢板的热成形过程进行数值模拟分析;计算板料与模具相互耦合的温度场变化规律,并将钢板组织相变释放的潜热考虑其中;将温度场计算结果引入热成形热、力、相变多场耦合的本构方程和静力显式有限元列式中,计算钢板等效应力和组织相变分布变化规律.通过钢板温度场以及马氏体转变量数值模拟结果与试验结果的一致性对比,验证建立的多场耦合本构模型和KMAS热成形仿真模块的正确性和有效性.     

基于模糊熵的16V280ZJA型柴油机缸盖螺栓的可靠性优化设计

缸盖螺栓工作的可靠性将严重影响柴油机运动件的整体动平衡、功率及油耗状况。将模糊设计与优化设计理论相结合,并引入熵理论,整理并推导出柴油机缸盖螺栓可靠性优化设计数学模型,通过Matlab编程实现数值解的计算及图形输出。该方法在DF8B型货运内燃机车装用的16V280ZJA型柴油机上进行了实例设计,结果表明,该方法设计的螺栓比原设计方案的质量减小了55.56%,优化效果十分明显。     

Effect of Peroxiredoxin 1 on the biological function of airway epithelial cells and epithelial-mesenchymal transition

Peroxiredoxin 1 (PRDX1) participates in tumor cell proliferation, apoptosis, migration, invasion, and the epithelial-to-mesenchymal transition (EMT). This study aimed to investigate the effect of PRDX1 on the EMT of airway epithelial cells stimulated with lipopolysaccharide (LPS) and transforming growth factor-beta 1 (TGF-β1). PRDX1 overexpression significantly increased the proliferation and migration of human bronchial epithelial (BEAS-2B) cells, reduced cell apoptosis (p < 0.01), and induced EMT and collagen deposition by upregulating the expression of the matrix metallopeptidase (MMP)2, MMP9, α-smooth muscle actin (α-SMA), N-cadherin, vimentin and twist proteins and inhibiting E-cadherin expression (p < 0.05). PRDX1 overexpression promoted TGF-β1-mediated inhibition of cell proliferation and migration and significantly enhanced the TGF-β1-induced EMT and collagen synthesis (p < 0.05). Knockdown of PRDX1 inhibited cell proliferation, migration, EMT, and collagen synthesis (p < 0.01), reversed LPS-mediated inhibition of cell proliferation and migration, and significantly suppressed LPS-induced EMT and collagen synthesis (p < 0.01). The result indicating that PRDX1 may be involved in LPS/TGF-1-induced EMT and collagen synthesis in human bronchial epithelial cells.     

基于启发式算法的农机混流装配线平衡分析与优化

针对某农机企业装配车间生产效率低下的问题,以玉米机装配线为研究对象,对其构建和优化混流装配线进行了研究.首先计算了玉米机不同型号产品构建混流装配线的综合作业时间,绘制了作业优先顺序图,然后运用启发式算法对该混流装配线的平衡问题进行了分析与优化,最后运用Flexsim仿真软件对混流装配线进行了动态仿真,以此验证了构建的混...     

基于安全系统工程设计方法的超高速铣床机械安全设计研究

阐述了机械产品安全系统工程设计方法的基本技术原则和主要内容,研究了机械产品安全系统工程设计方法在超高速铣床机械安全设计中的应用.     

SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION WITH MAGNETO- RHEOLOGICAL DAMPERS: PART Ⅰ-CONTROLLER SYNTHESIS AND EVALUATION

A modified skyhook-based semi-active controller is proposed for implementing an asymmetric control suspension design with symmetric magneto-rheological (MR) dampers. The controller is formulated in current form, which is modulated by integrating a continuous modulation and an asymmetric damping force generation algorithms, so as to effectively minimize switching and hysteretic effects from the MR-damper. The proposed controller is implemented with a quarter-vehicle MR-suspension model, and its relative response characteristics are thus evaluated in terms of defined performance measures under varying amplitude harmonic, rounded pulse and random excitations. The sensitivity of the semi-active suspension performance to variations in controller parameters is thoroughly evaluated. The results illustrate that the proposed skyhook-based asymmetric semi-active MR-suspension controller has superior robustness on the system parameter variations, and can achieve desirable multi-objective suspension performance.     

一种可直接脉冲调制的MEMS红外激发源

针对红外气体探测器对光源的要求,结合现有MEMS(微机电系统)工艺及与其兼容的IC工艺,研制了一种可用于红外多气体传感器的脉冲式MEMS辐射光源。该光源主要有Si₃N₄/SiO₂的复合支撑层和铂金发热电极组成,可以产生相当于黑体300~800 K的红外辐射,在温度T＝1 106 K时有λ=2.62 μm峰值辐射波长;并且光源有足够强的辐射强度和2~15 μm红外辐射波段,能够满足大部分气体在2~14 μm波长范围内特征的吸收谱线的要求。经过对辐射元的动态测量可知,辐射源的动态调制频率可达到50 Hz,完全能够满足气体测量对所需红外光源调制频率的要求。