At present mounts of optoelectronic measurement system have mainly two kinds of frame , i . e . altitude - azimuth form and equatorial form . the vast majority of large telescopes built are of an altitude - azimuth pedestal design in order to track fast moving satellites 陆基型光学测量设备目前主要采用地平式和极轴式两种结构模式，由于地平式系统成本低，软硬件成熟度和工作可靠性高等原因，在观测人造卫星的仪器中绝大部分采用地平式装置。
Based on swmm ( storm water management model ) , a typical urban region is selected to calculate the status under the design storms with different frequencies in the region , such as drainage effect and water - logging , overland flow on road etc . , and simultaneously , the storm floods under different conditions , including reforming the protruding green belts into plain or concave ones , placing flood storage areas etc . , are simulated with the evaluation on their effects 摘要以swmm为基础，选取北京市典型小区，计算不同频率设计暴雨下小区排水效果以及积水、道路坡面流等情况，同时进行不同情景下的暴雨洪水模拟并评价其影响，包括改凸式绿地为平式和凹式、设置蓄洪区等。
At first , according to the concrete requirement of the servo control system , a collective scheme , which provide guarantee to meet the requirements of the global performance , is established . in this scheme , the structure of gimbal and the torque motor driven mode are adopted , and angle measurement is accomplished by inductosyn and velocity measurement is accomplished by dynamically tuned gyro respectively 首先，根据目标真值测量设备伺服系统的具体要求，确定了地平式常平架结构，力矩电机驱动，分别采用动力调谐式速率陀螺仪及圆盘式感应同步器作为速率及位置反馈元件这一总体方案，为伺服系统满足整体性能指标要求提供了保证。
In this paper the author assume that micro - cracks will occur in the concrete structure after damage threshold value is reached . because of existence of micro - cracks , it is very difficulty for us to analysis concrete ' s damage . the numerical method for analysis of damage failure is put forward through combination model of exponent function damage with model of smeared crack model 当混凝土结构在外载作用下进入损伤破坏阶段后，在本文内认为当混凝土结构内的损伤达到损伤阈值后，在结构内部将会产生微裂纹，由于这些裂缝的存在，使得混凝土结构的损伤分析变得异常困难，为此本文以抹平式裂纹模型为基础，引入指数函数损伤模型，以调整单元刚度的方法考虑裂纹和损伤的影响，建立了混凝土结构损伤破坏分析的数值方法，并进行了算例分析，取得了较好的结果。
That is , the occasional situation where the object of interest passes directly overhead ( 90 zenith pass ) . azimuth axis must rotate nearly 180 ? instantly . therefore , the standard two - axis altitude - azimuth pedestal will be unable to remain pointed at the object through the zenith pass event 所谓天顶盲区问题是指目标过天顶时对地平式设备方位轴有一个极大的过载要求，需要方位轴瞬时调转180 (或略小于180 ) ，此时方位变化的角速度和角加速度在数学意义上是无穷大，导致目标丢失。
