Investigation of helicopter maneuverability by the power balance method

The algorithms for calculating available overloads and maneuvers are presented. Nesterov’s loop maneuver is analyzed.     

Metal creep model with the initial strain discontinuity and functional material constants

It is proposed that curves of metal creep be approximated by the time-relative linear law with the initial creep strain discontinuity; as a result, the solution of initial boundary value rheological problems is considerably simplified and is characterized by the adequate precision with a large service life. The labor intensity of computations is similar to the steady-state creep law. The introduction of functional material constants makes it possible to perform calculations of creep under the action of temperature that is different from the specified one in the basic experiments as well as calculations of nonuniformly heated structure elements.     

美国液体推进剂标准化发展状况

概述液体推进剂的适用范围、作用及其标准的分类,研究和分析美国液体推进剂各类标准的编制状况与发展趋势,并对各类标准的主要内容作了简介.     

平面波导器件封装工艺软件的研究与开发

平面波导器件的耦合封装是制约其发展的一个瓶颈,通过研究平面波导器件的封装工艺特点,分析了封装过程对控制系统的要求.基于Visual Basic.Net开发了封装工艺软件,研究了手动调整、视觉引导粗对准、自动化对准以及点胶固化四个模块的设计方法,并对编程过程中的关键技术进行了讨论.     

混杂系统的双测度稳定性及应用

近年来混杂系统的性质一直为人们所关注.系统的稳定性是衡量一个系统的重要指标.主要讨论了混杂系统的双测度稳定性,给出混杂系统双测度稳定性的判别准则.最后,介绍了甘油连续方式发酵1.3-丙二醇的动力系统,并借助上面的版别准则说明此动力系统是双测度稳定的.     

基于交叉验证的捷联惯导制导工具误差分离方法

在捷联惯导制导工具误差分离过程中引入交叉验证检验制导工具误差分离精度,并基于均方误差准则建立量化检验指标.首先建立简化的制导工具误差分离模型,并将数据划分成训练集和检验集;然后利用训练集进行制导工具误差分离;最后利用检验集和量化检验指标对分离效果进行检验.数学仿真表明,提出的误差分离模型正确可靠,精度较高,交叉验证能够对分离效果进行有效检验.     

基于改进最小模算法的弹载圆阵抗诱偏技术

为了保证反辐射导弹(ARM)的有效杀伤力,基于非相干两点源的诱偏原理,设计了一种弹载小型圆阵,同时在改进最小模算法(MNM)的基础上,估计辐射源的到达角(DOA),从而实现对目标雷达及诱饵的定位。给出了均匀圆阵下最小模算法的原理及其改进算法,并对七元阵结构下的非相干的三辐射源进行仿真,仿真结果证明了该方法的有效性。     

浅析继续教育在区域经济发展中的作用

本文研究了继续教育对区域经济发展的重要意义。首先分析了继续教育在经济发展中的必要性,指出了继续教育在校企合作中遇到的问题,进而针对上述问题提出了完善校企合作的建议,并结合北华航天工业学院的继续教学院的人才培养实践,提出了有针对性的有效校企合作机制。     

Relative occurrence rate and geoeffectiveness of large-scale types of the solar wind

We investigate the relative occurrence rate for various types of the solar wind and their geoeffectiveness for magnetic storms with Dst < —50 nT. Both integrated effect for the entire time 1976–2000 and variations during this period of 2.5 cycles of solar activity are studied As raw data for the analysis we have used the catalog of large-scale types of the solar wind for the period 1976-2000 (see ftp://ftp.iki.rssi.ru/omni/) created by us with the use of the OMNI database (http://omni.web.gsgc.nasa.gov) [1] and described in detail in [2]. The average annual numbers of different type of events are as follows: 124 ±81 for the heliospheric current sheet (HCS), 8 ±6 for magnetic clouds (MC), 99 ±38 for Ejecta, 46 ±19 for Sheath before Ejecta, 6 ±5 for Sheath before MC, and 63 ±15 for CIR. The measurements that allowed one to determine a source in the solar wind were available only for 58% of moderate and strong magnetic storms (with index Dst < —50 nT) during the period 1976–2000. Magnetic clouds (MC) are shown to be the most geoeffective (~61%). The CIR events and Ejecta with Sheath region are three times less geoeffective (~20–21 %). Variations of occurrence rate and geoeffectiveness of various types of the solar wind in the solar cycle are discussed.     

复合材料的切削加工技术

复合材料在航空、航天等工业中得到越来越多的应用.复合材料的种类很多,基体材料分金属和非金属两大类,增强材料分纤维和颗粒两大类.对复合材料进行切削加工的难度较大,一般需采用超硬刀具.