We also provide engineering services for the day - to - day maintenance , routine inspection and testing , fault and complaint attendance , minor repairs , term contract management and standard stores management for electrical installations 我们的服务驻点遍布全港, 24小时随时候命,确保能迅速回应紧急故障召唤。
Martin ( ref . 36 ) proved the equivalence between some invexity and the case that every stationary point or kuhn - tucker point is a global minimum point for unconstrained or constrained scalar programming Martin在文献[ 36 ]中,证明了无约束或约束单目标规划中某类不变凸性与每个驻点(或k - t点)即为全局最优点的等价性。
The calculation of stagnation point position of straight pipeline section with both movable ends and l - type pipeline section with bend at one end and bellows type expansion joint at other end is discussed 摘要探讨了两侧为活动端的直管段及一侧活动端为弯头,而另一侧活动端为波纹管补偿器的水平转角管段驻点位置的计算。
The spot operation : provide to halt some type service with the form of the office , fixedly adjust one degree personnel fixs the spot manager , carry each link within process to link up with the operation assurance of norm perfect 现场操作:以办事处形式提供驻点式服务,固定调度人员固定现场管理人员、以规范的操作保证运过程中的每个环节的衔接完善。
Micro - jets impingement cooling heat sink is used to cool the high power lda owing to the very thin hydrodynamic and thermal boundary layers in the impingement region when a jet impinges on a surface . reasonable array of jets can develop the uniform of temperature distribution on target very much 微射流阵列冷却热沉,是利用射流冲击在驻点区能产生很薄的边界层来提高换热效率的,合理的布置射流孔,可以极大的提高被冷却表面温度分布的均匀性。
Motivated by the above results , the third part of this paper considers the equivalence problems that every stationary point or kuhn - tucker point is an efficient solution . we define i - quasi - invex vector function . , i - strictly quasi - invex vector function and kt - i - strictly quasi invex vector function , and derive the above equivalent condition for unconstrained or constrained multiobjective programming 于是,在本文的第三部分,我们定义了类不变拟凸、类严格不变拟凸、 kt -类严格不变拟凸的向量值函数,并且在无约束或约束多目标规划中,获得了每个驻点(或k - t点)是有效解的等价条件。
Thirdly , this dissertation briefly introduces the engineering estimation method of the aerodynamic heat and supplies the simplified formulas . not considering the rejection , the ablation and some other factors , the author calculates the stagnation heat flux and the non - stagnation field heat flux distribution of some fly situation as the example aerodynamic heat environment . finally , by using the ansys program , the thermal vibration characters of the plate and missile body structures with different materials is analyzed 这一方法提高了热振动的分析效率;第三,简要的介绍了工程上计算气动熟的估算方法及热流密度计算的简化公式,在不考虑烧蚀以及质量引射等影响下,本文计算了几种飞行条件下驻点和非驻点区的热流密度分布,作为本论文算例的气动加热环境。
In the thesis the low drag - low noise optimization of the vehicle main form design is realized , main accomplishments are as follows . researched the knowledge of drag and flow noise , the parameters of the boundary layer are calculated by the hess - smith method and boundary layer momentum integral method . the calculation of the length of transition zone and change in boundary layer displacement thickness between laminar and turbulent states in the transition is improved , then the drag coefficient and self - noise from the transition zone are calculated as the objective functions of the optimization 主要研究内容和成果如下:对航行器绕流流场进行分析,深入研究了阻力和流噪声产生机理,建立了阻力系数和自噪声的评估数值计算模型;采用物面分布源汇法和边界层动量积分法对绕流流场的流体动力参数进行计算,改进了转捩区长度和边界层位移厚度的计算,应用于航行器头部驻点自噪声的计算;最后设计了阻力系数和自噪声数值计算程序模块。
Abstract : approximate methods for calculating aerodynamic heating rates on space shuttles are discussed . various methods are given for predicting the heating rate at axisymmetric stagnation points , general three dimensional stagnationpoints and the leading edge stagnation point of wings . numerous laminar and turbulent heating techniques for flat plates and cones are analyzed and compared . a brief review of some methods is presented to predict heating rate for winward centerline and lateral direction off the symmetry plane . the results show that the methods are simpler and can guarantee enought precision for predicting aerodynamic heating environment of space shuttles 文摘:介绍了国内外预测航天飞机气动加热的工程计算方法.给出了轴对称、非轴对称和机翼前缘等各种外形驻点热流密度的计算,分析和比较了平板、锥体的层流和湍流热流密度计算的各种方法,概述了航天飞机迎风面中心线和离开中心线横向热流密度的计算.计算结果表明,本文方法用在航天飞机气动热环境初步设计中比较简单并且有足够精度