3 ) a 3 - d geometry and finite element model of the assembly of the obturator of the breech mechanism is established . quasi - static and dynamic finite element analysis of stiffness , strength and obturating performance of the obturator of the breech mechanism is carried out , based on elastoplastic theory and multi - body contact algorithm , and the simulation results coincide with experimental results , further , th e effect of friction factor on its obturating performance is investigated 建立了炮闩闭气结构的三维装配体几何实体模型和有限元模型，对炮闩闭气结构刚强度和闭气性能进行了准静态及动态多体接触弹塑性有限元分析，分析结果与试验结果相吻合，进一步研究了摩擦系数对其闭气性能的影响。
Non - steady transient thermal elastohydrodynamic lubrication analysis model based on surface roughness in high - speed cylindrical roller bearing has been established , and effects of roughness amplitude , wavelength , and texture in contact surface of raceway and rolling element on bearing elastohydrodynamic lubrication performance are analysed 摘要建立了基于表面粗糙的高速圆柱滚子轴承非稳态时变热弹流分析模型，分析了抽承滚道与滚动体接触表面粗糙度幅值大小及其方向对轴承弹流性能的影响。
The immersion electrical heater is chiefly applied in the direct contact mode of fluid heating . it features fast heat exchange and high thermal efficiency . it has the varieties of water heater , oil heater and gas heater . its heating element power density , i . e . the power per unit of heating area of the heating element , is an important parameter of the electrical heating element , which has a direct bearing on the performance and working life . the working out of the value is a highly specialized problem , being under the influence of many factors ( media flow rate , tempt , physical and chemical properties and direction in which the medium flows past the element etc ) 浸入式电加热器主要用于直接对流体接触加热的场合，具有热交换快，热效率高等特点，分为水用加热器、油用加热器、气体用加热器，加热元件的功率密度：即电加热元件单位发热面积上的功率，它是电加热元件极重要的参数，直接影响加热器的使用性能及使用寿命，它的取值是一个非常专业的问题，受到许多因素的影响（如介质的流速、温度、物理和化学性质及介质流过加热元件的方向等等） 。
