Link-16战术数据链抗干扰性能评估与仿真

分析了JTIDS系统的结构与特点,重点探讨了其抗干扰性能,在Simulink仿真平台实现了对JTIDS系统的仿真,给出了具体的仿真模型并对模型中的每个模块进行了较为详细的说明,对仿真结果进行了简要分析.     

阵列测向半实物仿真硬件平台设计和实现

分析了阵列信号处理算法实用化过程中存在的一些问题,总结了DOA估计快速算法.研究了软硬件设计应具有的功能,提出并实现了基于FPGA DSP的阵列信号半实物仿真硬件平台,指出了下一步研究的方向.     

X6232型铣床的拓宽加工

论述了由龙门铣床加工改为普通万能铣床加工工艺方案的实施过程。此项工艺研究不仅有效地保证了工件的加工精度，缓解了大型设备的紧张生产状况，而且降低了成本、提高了效益，为拓宽普通铣床的加工范围积累了经验。     

卫星通信中的超宽带无线技术研究

首先介绍了超宽带技术的定义,描述了超宽带技术的特点和调制方式,分析了在卫星通信中采用超宽带技术的可行性;然后给出了一种采用超宽带技术的固定卫星通信系统结构,给出了系统链路预算,并对多载波方案的系统吞吐量进行了分析计算;最后给出了结论和需要进一步研究的问题。     

从新会计准则角度探析上市公司盈余管理

新会计准则的出台对我国上市公司的会计核算带来了实质性的影响，与原来的准则相比，毫无疑问新准则有了极大的完善，向国际会计准则的趋同迈出了一大步。本文以新会计准则出台为契机，从盈余管理的内涵入手，揭示了会计准则与盈余管理的关系，剖析了新会计准则对上市公司盈余管理的制约因素，分析了新会计准则下盈余管理提供了新的利润操纵空间以及探讨了新会计准则下对上市公司盈余管理的规范措施。     

卫星服务舱湿度控制系统性能分析及改进研究

文章介绍了卫星服务舱湿度控制系统的组成及工作原理。采用分析和测定相结合的方法建立了基于传递函数的系统的数学模型,通过试验验证了该模型的准确性, 并用模型分析了系统性能, 分析结果表明系统性能满足了技术指标的要求。文章最后提出了进一步提高系统性能的主要途径,这为改进系统设计提供了理论依据。     

浮珠保温冒出口在铝合金叶片上的应用

金属型冒口尺寸较大，不仅浪费金属液而且清理费用高，同时还不易保证铸件内部质量。采用了浮珠保温冒口后，使铸件得到了良好的补缩，提高了铸件的内部质量；由于冒口直径的缩小节约了铝液，给清理工作带来了很大方便，降低了铸件成本，提高了经济效益。     

过氧化氢推力室技术研究

简述了过氧化氢作为火箭推进剂的优点,重点介绍了近几年陕西动力机械设计研究所在过氧化氢单组元推力室和双组元发动机推力室研制中取得的进展。设计了几种过氧化氢单组元推力室并进行了试验;进行了过氧化氢／煤油双组元火药点火试验;进行了催化点火技术的研究,27次点火试验全部取得成功;设计并生产了几种双组元推力室,对过氧化氢／煤油自燃点火技术进行了研究,累计进行了500余次点火试验;采用37kN推力室分别进行了90％过氧化氢／煤油的火药点火试验和自燃点火试验,试验获得了成功。     

空间拦截中只测量视线角速度的跟踪滤波器的可观性分析

建立了空间拦截中导弹与目标的相对运动方程。论述了卡尔曼滤波器的可观性准则，研究了跟踪滤波器的可观性，并分析了影响跟踪滤波器可观性的因素。数字仿真证实了理论的正确性。     

神舟项目管理成熟度模型的建立与应用

综合分析了神舟飞船研制管理历程，提炼了项目管理成熟过程，在研究了国际上典型的项目管理成熟度模型基础上，建立了神舟项目管理成熟度模型，给出了模型的应用步骤和应用方法。     

Analysis of the Accuracy of Ballistic Descent from a Circular Circumterrestrial Orbit

The problem of the transportation of the results of experiments and observations to Earth every so often appears in space research. Its simplest and low-cost solution is the employment of a small ballistic reentry spacecraft. Such a spacecraft has no system of control of the descent trajectory in the atmosphere. This can result in a large spread of landing points, which make it difficult to search for the spacecraft and very often a safe landing. In this work, a choice of a compromise scheme of the flight is considered, which includes the optimum braking maneuver, adequate conditions of the entry into the atmosphere with limited heating and overload, and also the possibility of landing within the limits of a circle with a radius of 12.5 km. The following disturbing factors were taken into account in the analysis of the accuracy of landing: the errors of the braking impulse execution, the variations of the atmosphere density and the wind, the error of the specification of the ballistic coefficient of the reentry spacecraft, and a displacement of its center of mass from the symmetry axis. It is demonstrated that the optimum maneuver assures the maximum absolute value of the reentry angle and the insensitivity of the trajectory of descent with respect to small errors of orientation of the braking engine in the plane of the orbit. It is also demonstrated that the possible error of the landing point due to the error of specification of the ballistic coefficient does not depend (in the linear approximation) upon its value and depends only upon the reentry angle and the accuracy of specification of this coefficient. A guided parachute with an aerodynamic efficiency of about two should be used at the last leg of the reentry trajectory. This will allow one to land in a prescribed range and to produce adequate conditions for the interception of the reentry spacecraft by a helicopter in order to prevent a rough landing.     

基于羽流效应分析的航天器发动机布局设计研究

为解决由航天器姿控发动机等带来的羽流热效应问题,文章通过仿真得到了在不同的发动机布局下航天器表面的羽流热流密度分布情况,通过增大发动机的推力线角度和安装点高度,可以使得发动机羽流核心区远离航天器表面,从而降低喷流对航天器表面的加热效应。综合考虑控制力矩及推力损失、布局包络和发动机支架设计等因素,对某航天器发动机布局进行了优化设计及羽流热防护设计。     

航天材料基因工程及其若干关键技术

材料基因工程的理念和将空间环境与效应纳入到航天材料研制全流程的思路将对航天材料的开发带来颠覆性的革命。文章在对国内外材料基因组计划和航天材料需求分析的基础上,首先对航天材料基因工程的内涵进行阐述,进而对基于航天材料基因工程的航天材料研制流程进行分析,最后结合空间环境效应及材料基因工程,从计算工具、试验工具、数字化数据三个维度,提出空间多因素环境与航天材料的耦合作用机理、航天材料空间多因素环境效应等效评价方法、空间复杂使役环境下航天材料性能演化模型、航天材料空间环境效应数据库、基于材料基因工程的航天材料设计模型、航天材料研制的不确定性及优化方法等关键技术和发展方向。     

Estimate of accuracy of determining the orientation of the star sensor system according to the experimental data

The BOKZ-M60 star sensor (Unit for Measuring Star Coordinates) is intended for determining the parameters of the orientation of the axes of the intrinsic coordinate system relative to the axes of the inertial system by observations of the regions of the stellar sky. It is convenient to characterize an error of the single determination of the orientation of the intrinsic coordinate system of the sensor by the vector of an infinitesimal turn of this system relative to its found position. Full-scale ground-based tests have shown that, for a resting sensor the root-mean-square values of the components of this vector along the axes of the intrinsic coordinate system lying in the plane of the sensor CCD matrix are less than 2″ and the component along the axis perpendicular to the matrix plane is characterized by the root-mean-square value of 15″. The joint processing of one-stage readings of several sensors installed on the same platform allows us to improve the indicated accuracy characteristics. In this paper, estimates of the accuracy of systems from BOKZ-M60 with two and four sensors performed from measurements carried out during the normal operation of these sensors on the Resurs-P satellite are given. Processing the measurements of the sensor system allowed us to increase the accuracy of determining the each of their orientations and to study random and systematic errors in these measurements.     

镁铝贫氧推进剂的能量分析

利用冲压发动机热力计算程序，对镁铝中能贫氧推进剂的能量特性进行了系统研究，并探讨了高能级分对该类贫氧推进剂能量性能的影响，研究结果表明，在镁铝中能贫氧推进剂中增加镁粉含量（或减少铝粉含量）贫氧推进剂的比冲下降，在一定空燃比范围内，增加空燃比有助于提高冲压发动机的比冲。提高贫氧推进剂中ＣＬ－２０和硼粉含量，可以显著提高共能量，而采用叠氮类含能粘合剂取代惰性粘合剂时贫氧推进剂的比冲降低。     

舱压对载人航天器密封舱姿态光学敏感器安装精度影响分析

姿态光学敏感器是航天器在轨姿态控制的重要部件,其安装精度直接影响航天器的姿态控制精度。为了研究舱压对载人航天器密封舱姿态光学敏感器安装精度的影响,以某载人航天器密封舱外安装的姿态光学敏感器为研究对象,通过对其安装精度要求、安装状态与舱体变形情况的分析,提出了一种敏感器在设计阶段布局的分析方法。在地面进行了模拟充压试验,验证了分析方法的有效性。根据分析和试验结果在型号后续设计中进行了相应的布局改进,改进结果满足了敏感器安装精度要求并经过了飞行试验验证。     

航天器新型高密度排插型DC10电缆安装技术

以互联网卫星上首次使用的新型高密度排插型电缆组件为研究对象,介绍了集成式排插型电连接器的制造技术要求和工作原理,从电连接器结构分析出发,研究影响该类型电缆的安装因素。首次提出了新型高密度排插型电缆的安装方法,阐述了该类型电缆的弯曲半径要求、绑扎要求、紧固力矩值要求和使用专用工装的拆卸方法。经过分系统的实际在轨性能测试验证,该安装技术可以显著降低新型高密度排插型电缆组件在大通量、高饱和度信号传输状态下性能下降的现象,成功解决了该类型电缆在卫星狭小空间下的安装与拆卸难题,提高了该类型电缆在卫星狭小空间内的安装精度和分系统的在轨可靠性,为该新型高密度排插型电缆组件的安装在后续卫星批量应用提供了技术指导和工艺基础。     

寻求一片纯洁的天空——《受活》的一种解读

《受活》这部作品以写实和荒诞的笔调,在历史和现实中回环往复,书写了历史与现实中存在的乌托邦幻想与冲动,以及这些乌托邦行为给底层人们带来的苦难,并通过对人物心灵的剖析透视了乌托邦梦想的困境。在对残疾人与圆全人两个世界的对比中,作者肯定了受活人的生存状态,表达了对那种自由自在以及纯洁的心灵世界的向往与追求。     

Multipole Models of the Earth's Magnetic Field

To develop a mathematical model of rotational motion of an artificial satellite about its center of mass under the action of various forces (magnetic, Lorentz, etc.) caused by the geomagnetic field, it is necessary to know the induction of the Earth's magnetic field (EMF) as a function of the radius vector of a given point in the near-Earth space. Because the EMF possesses a complex structure and the above-mentioned functional dependence is unavailable in explicit analytic form, a set of approximate models of the EMF should be used. The simplest such model—a right dipole (aligned with the axis of rotation)—does not enable one to reveal in detail the influence of diurnal EMF rotation on the rotational motion of a satellite. The next EMF approximation—an inclined magnetic dipole—does not suffer from the above-mentioned drawback. However, it is shown that not all corrections to the magnetic induction of the EMF of the same order of magnitude are taken into account in the course of transformation from the model of aligned dipole to the model of inclined dipole. So, to develop the EMF model accurately accounting for the absence of axial symmetry of the EMF with respect to the axis of diurnal rotation of the Earth, in general, the effect of the quadrupole component of the geomagnetic potential on the EMF induction (and, probably, even the components of higher orders) must be taken into consideration. By using the International Geomagnetic Reference Field IGRF-2000, the multipole models of the EMF, corresponding to quadrupole, octupole, and higher-order approximations, were constructed and studied in this work. The EMF potential is expressed in terms of its multipole tensors. As a result, projections of the induction and induction gradient of EMF in the center of mass of the satellite onto the axes of the orbital coordinate system can be written in convenient and concise form. The expressions for the first four multipole tensors through the known geomagnetic constants are found. A method for estimating the reliability of these models is put forward, and the regions of applicability of the quadrupole and octupole models are drawn on the plane of orbital parameters.     

Synthesis of a combined system for precise stabilization of the Spektr-UF observatory: II

The paper presents the second part of the results of search studies for the development of a combined system of high-precision stabilization of the optical telescope for the designed Spectr-UF international observatory [1]. A new modification of the strict method of the synthesis of nonlinear discrete-continuous stabilization systems with uncertainties is described, which is based on the minimization of the guaranteed accuracy estimate calculated using vector Lyapunov functions. Using this method, the synthesis of the feedback parameters in the mode of precise inertial stabilization of the optical telescope axis is performed taking the design nonrigidity, quantization of signals over time and level, and errors of orientation meters, as well as the errors and limitation of control moments of executive engine-flywheels into account. The results of numerical experiments that demonstrate the quality of the synthesized system are presented.