我心目中的空管人

空管,我并不陌生,甚至曾经走得很近。空管,也曾是我为之努力的理想。本科四年,在飞行学院学的正是空中交通管制,而且还是该校的第一届“。右转30度”“爬升至9000米报告”,面对模拟机上密密麻麻的飞机,一条条指令由我们口中发出,那是一种自豪,那更是一种责任。模拟机训练构建了     

漂亮的军火出口成绩单 2004年俄罗斯军火销售的绩效评析

在政府的积极推动下．俄罗斯2004年的军火销售再度取得55亿美元的亮丽成绩，销售的种类和层次不仅已有所提升，在北非和阿拉伯半岛的军火市场亦有所突破。不过俄国军火企业的基本问题倘无法获得解决，对其未来发展恐怕会有相当影响，非常值得注意。     

New split-winding doubly salient permanent magnet motor drive

A new split-winding doubly salient permanent magnet (DSPM) motor drive is proposed. This DSPM motor drive offers the advantages of high power density, high efficiency, and wide speed range. The corresponding operation, analysis, implementation, and experimentation are successively presented. Finally, experimental results are used to confirm that the proposed DSPM motor drive offers high efficiency over a wide output power range, exhibits good dynamic performance, and extends the constant-power operation range significantly.     

对当前就业问题的思考

“十五”期间正值我国就业的高峰时期,解决好就业问题,首先要摸清现阶段就业状况及导致失业的原因,提出相应的解决对策,无疑是具有积极意义的。     

AE9, AP9 and SPM: New Models for Specifying the Trapped Energetic Particle and Space Plasma Environment

The radiation belts and plasma in the Earth’s magnetosphere pose hazards to satellite systems which restrict design and orbit options with a resultant impact on mission performance and cost. For decades the standard space environment specification used for spacecraft design has been provided by the NASA AE8 and AP8 trapped radiation belt models. There are well-known limitations on their performance, however, and the need for a new trapped radiation and plasma model has been recognized by the engineering community for some time. To address this challenge a new set of models, denoted AE9/AP9/SPM, for energetic electrons, energetic protons and space plasma has been developed. The new models offer significant improvements including more detailed spatial resolution and the quantification of uncertainty due to both space weather and instrument errors. Fundamental to the model design, construction and operation are a number of new data sets and a novel statistical approach which captures first order temporal and spatial correlations allowing for the Monte-Carlo estimation of flux thresholds for user-specified percentile levels (e.g., 50th and 95th) over the course of the mission. An overview of the model architecture, data reduction methods, statistics algorithms, user application and initial validation is presented in this paper.     

Random signal radar - a winner in both the military and civilian operating environments

Besides some general requirements, modern military radars should possess excellent LPI (low probability of intercept) properties. And civilian radars should satisfy the rigorous requirement of EMC (electro-magnetic compatibility) performance. The special features of random signal radar are analyzed here based on the different requirements for military and civilian use. Results show that random signal radar has excellent LPI property and EMC performance simultaneously, which can satisfy both military and civilian requirements.     

位同步提取环路带宽的自适应控制的研究

本文主要研究数字匹配滤波器在位同步提取环路带宽的自适应控制中的应用。首先，从理论上分析了匹配滤波器的误码性能，定量地推出数字匹配滤波器的误码率计算公式；然后，分析了输入信噪比与数字匹配滤波器输出状态的关系；最后，给出了位同步提取环路带宽的自适应控制的硬件实现方案。     

新体制卫星导航信号特性与跟踪环路设计

从新体制卫星信号的特性出发,论述新体制卫星导航信号跟踪环路的一种实现方式,即三环双估计器跟踪环路的设计方法,并以一个仿真系统为例给出各项参数推导的详细过程,最终的仿真结果证明所述方法合理可行。     

吸气式脉冲爆震发动机壁温试验

为了探索各频率下管壁温度随时间的变化趋势及爆震管外壁面的温度分布规律,对爆震室内径68mm,长2 000mm,以汽油为燃料、空气为氧化剂的吸气式脉冲爆震发动机进行试验,用热成像仪对稳定工作在10Hz,20Hz,40Hz下的管壁温度进行了监测。结果表明:同一频率下随时间的增加壁面温度增加速度减小;热平衡时壁面温度随频率的增加而增长,10Hz,20Hz,40Hz热平衡时外壁面最高温度分别在726℃,1011.5℃,1159.5℃以上;热平衡前管壁温度的增长速度随频率的增加而增加,管壁温度的增长速度跟频率约成正比;爆震室上沿着压缩波叠加至形成爆震的方向,温度在外壁面上递增分布,在爆震形成区温度最高,从爆震形成区到发动机出口处,温度在外壁面上逐渐降低;各频率下最高温度区位置基本不变,距点火位置1 350mm左右;同一轴向位置上的外壁面温度随频率的增加而增加,温度的增长幅度随频率的增加而减小。     

高层建筑的防火安全对策

针对高层建筑的特点，分析了高层建筑发生火灾的危险性和危害性，对提高高层建筑消防安全需要进行全面系统设计，实施全方位科学运作，加强各方面综合协调，并对防范火灾发生，控制火灾扩大，确保安全疏散等问题进行了探讨。