Seismo-Ionospheric Variations during Strong Earthquakes Based on the Example of the 2010 Earthquake in Chile

Seismo-ionospheric variations during the strong earthquake on February 27, 2010 in Chile have been considered. An analysis of the ionospheric state has been performed using measurements based on a GPS satellite navigation system. The results of processing have shown that the decrease in the electron concentration on February 24, 2010 relative to the preceding day was from 24 to 35%. It has also been noted that, 3 days prior to the seismic event, a substantial drop in the rate of change of in the total electron content was observed near the epicenter zone for 1.5 h. It has been shown that, directly before the earthquake, instantaneous variations in the rate of change in the electron content by an order of value that exceeds normal background behavior was observed.     

光学太阳反射镜抗静电薄膜的设计原则

对氧化铟锡（ITO）薄膜在光学太阳反射镜（OSR）抗静电放电设计中的应用进行了研究，采用Drude理论分析了ITO薄膜的表面方阻等对OSR的太阳光谱吸收比的影响，测试了光学太阳反射镜充电电位，讨论了薄膜接地状况对OSR表面充放电性能的影响，结果表明，ITO薄膜应用于OSR表面防静电放电时，需合理设计表面方阻和接地方式。     

A comparison between the 19th century early proposals and the 20th–21st centuries realized projects intended to contact other planets

Methods dealing with how to contact other planets that are supposed to be inhabited by “intelligent” civilizations have begun more than one century and a half ago. The historical question has been already treated in several studies and the aim of this paper is not to provide details on that aspect. On the other hand, it could be interesting to make a comparison between the different approaches to contact planets, formulated at different epochs (even if obviously techniques were not in the same state of advancement). The most important characteristics of the earliest messages, remained only on a theoretical form, will be presented. The main features of modern messages, which have been concretely realized, will also be emphasized. Drawing a parallel between these two series of projects could demonstrate what has been considered as unavoidable by both pioneer and modern messages creators, while it has not been proved that the first ones have had any influence on the second ones. The common points emerging from this comparison could then (perhaps) help to select adequate models for an intelligible message intended to ETs, particularly concerning the language forms. Besides this, the differences could illustrate the human cultural advances in the field of METI and underline the tendencies that have been chosen in that field since the last decades.     

星载FPGA内时序电路设计与时钟控制技术分析

在分析星载FPGA内时序电路特性以及FPGA可编程资源特性的基础上,指出了FPGA内同步时序电路出现时钟偏斜现象的机理。针对时钟偏斜,提出了星载FPGA内时序电路的设计准则。基于设计准则,提出了并行移位寄存器的一种异步化设计方法,阐述了在FPGA源代码中设置设计约束,或在逻辑综合与布局布线过程中联合设置设计约束,将主要同步时序电路时钟信号布置在全局时钟网络上的方法。工程实践表明：上述方法很好地解决了星载FPGA内同步时序电路时钟偏斜问题,可确保星载FPGA工作的稳定性与可靠性。     

基于电磁矢量传感器阵列的广义旁瓣相消器

提出一种基于特殊电磁矢量传感器阵列的广义旁瓣相消器。首先在理论层面推导得到广义旁瓣相消器最优权矢量;针对信号是否在偶极子均匀圆阵处发生极化失配的四种情况进行讨论,进而明确阵列广义旁瓣相消器的适用场合;最后对广义旁瓣相消器和Capon波束形成器进行性能对比。理论分析和仿真实验表明,将广义旁瓣相消器推广到电磁矢量传感器阵列...     

Assessing the legacy of the Space Shuttle

This article reviews the core legacies of the Space Shuttle program after 25 years and suggests that, while it was not an unadulterated success, on balance the Shuttle served a valuable role in the development of spaceflight and deserves an overall positive assessment in history. There are five core legacies that deserve discussion. First, the Space Shuttle has a reputation as a mistake resulting from a policy failure that should never have been pursued. Second, it has been criticized as a program that prohibited other paths for the US space program. Third, and more positively, the Space Shuttle provided more than two decades of significant human spaceflight capability and stretched the nature of what could be accomplished in Earth orbit much beyond where it had previously been. Fourth, it served as a relatively flexible platform for scientific activities. Finally, and perhaps most significantly since the US human spaceflight program has always been focused on national prestige, the Space Shuttle served well as a symbol of American technological verisimilitude.     

A Study of the Destruction of Spacecraft Surfaces at Contact Interactions with Microparticles of the Space Environment

The results of studying the high-velocity impact interactions of a particle flux of space’s meteoric background with satellites have been presented. The effects that arises during the microparticle motion in the material have been described; the models of solid particle interactions with spacecraft’s onboard hardware protection have been presented. The experimental and analytical dependences have been given. The basic factors have been revealed, and their effect on the erosion wear of satellite’s surface has been estimated. The dependences for calculating the rectilinear (horizontal, inclined and vertical) sections of satellite’s surface have been given. The presented dependences represent the results of experimental and analytical studies.     

Theory of physical libration of the Moon with the liquid core: Forced librations

For a two-layer model of the Moon that consists of a solid nonspherical mantle and an ellipsoidal homogeneous liquid core, a theory of forced librations under the effect of gravitational Earth’s moments has been developed. The motion of the Moon over its orbit has been described by the high-accuracy theory of DE/LE-4 orbital motion. Tables have been constructed that present forced librations of the Moon caused by the second harmonic of its force function, in the neighborhood of its motion according to the generalized Cassini laws. Disturbances of the first-order with respect to dynamic compressions of the Moon and its core are obtained in analytical form for Andoyer variables and Poincare variables and for the projection of the angular velocity vector of Moon’s mantle rotation and the Poincare coordinate system (relative to which core’s liquid accomplishes simple motion) on its major central axes of inertia, as well as for the classical variables in the Moon libration theory, etc. Constructed tables of the forced librations theory give the amplitudes and periods of librations and combinations of arguments of the orbital motion theory that correspond to libration parameters. The interpretation of basic variations has been given and a comparison with the previous theories has been carried out, in particular with the modern empirical theory constructed based on the laser observation data.     

流量调节器研制中的主要问题及结构改进

介绍了一种用于液氧／煤油发动机的流量调节器的结构、原理。在调节器研制中出现的主要问题有滑阀卡滞、主级工况的负载特性存在负差率、转级活塞不能复位等。根据调节器的工作条件,运用静力学原理,分析了产生的原因,提出了改进方法,并进行了试验验证。试验结果表明：结构改进后的调节器工作可靠性得到了明显提高。     

Terraforming Mars: conceptual solutions to the problem of plant growth in low concentrations of oxygen

The widespread growth of higher plants on Mars following ecopoiesis has often been invoked as a method of generating atmospheric oxygen. However, one issue that has been overlooked in this regard is the fact that terrestrial plants do not thrive under conditions of low oxygen tension. A review of the relevant botanical literature reveals that the high oxygen demands of root respiration could limit the introduction of most plants on Mars until after terraforming has raised the atmospheric pO2 to 20-100 mbar. A variety of physiological strategies are discussed which, if it is possible to implement them in a genetically engineered plant specifically designed for life on Mars, might allow this problem to be overcome.     

星间光通信中BER的口径自适应控制法

从接收机的比特误码率与发射机的振动关系出发,采用OOK调制方式,以APD为光电探测器,推导得到了描述发射机天线口径与发射机振动关系的数学模型。针对比特误码率(BER)随振动幅值增加而上升的问题,提出了用发射天线口径与自适应方法控制BER的解决方案。用MATLAB6.5计算得到了自适应和标准条件下BER与跟踪系统信噪比的关系曲线。计算结果表明,采用天线口径自适应方法可将BER值控制在设计要求以下。     

Survival and germinability of Bacillus subtilis spores exposed to simulated Mars solar radiation: implications for life detection and planetary protection

Bacterial spores have been considered as microbial life that could survive interplanetary transport by natural impact processes or human spaceflight activity. Deposition of terrestrial microbes or their biosignature molecules onto the surface of Mars could negatively impact life detection experiments and planetary protection measures. Simulated Mars solar radiation, particularly the ultraviolet component, has been shown to reduce spore viability, but its effect on spore germination and resulting production of biosignature molecules has not been explored. We examined the survival and germinability of Bacillus subtilis spores exposed to simulated martian conditions that include solar radiation. Spores of B. subtilis that contain luciferase resulting from expression of an sspB-luxAB gene fusion were deposited on aluminum coupons to simulate deposition on spacecraft surfaces and exposed to simulated Mars atmosphere and solar radiation. The equivalent of 42 min of simulated Mars solar radiation exposure reduced spore viability by nearly 3 logs, while germination-induced bioluminescence, a measure of germination metabolism, was reduced by less than 1 log. The data indicate that spores can retain the potential to initiate germination-associated metabolic processes and produce biological signature molecules after being rendered nonviable by exposure to Mars solar radiation.     

基于模糊理论的航天发射场火箭煤油贮存泄漏风险研究

分析了导致火箭煤油发生泄漏事故的危险因素,对各影响因素进行了分类,通过层次分析法确定各因素的权重,运用模糊综合评价法对泄漏事故风险进行评价。评价结果表明火箭煤油在贮存过程中出现泄漏事故的风险等级为第4等级,即风险处于“较大”级别。     

一种新型燃速催化剂的作用效果研究

合成了一种新型二茂铁化合物—1,1—双(三甲基硅氧乙基)二茂铁,并研究了这种化合物对AP/HTPB复合推进剂燃烧性能、力学性能以及工艺性能的影响。实验结果表明,这种化合物具有改善推进剂燃烧性能和力学性能的双重作用。     

常增益递推滤波器的输出误差

一个常增益递推滤波器的误差源为初始估值误差、输入随机误差和滤波器预测截断误差。这些误差在滤波器中传播就构成输出误差。本文导出了输出随机误差协方差矩阵和输出截断误差矢量的表示式,并在讨论矩阵幂级数范数表示式的基础上,给出了输出误差范数的表示式。     

高超音速飞行器气动加热计算

对高超音速飞行器气动加热计算方法进行研究，采用基于热流量平衡方程的工程估算方法和二维薄层近似N－S方程数值模拟，计算高超音速飞行器对称面中心线上的温度分布。以天地往返运输系统的气动加热为例进行了计算，并对计算结果进行了分析和比较，计算结果表明：该工程估算方法和数值计算方法是可行的。     

含微裂纹的固体导弹弹射筒的可靠性研究

为了对含微裂纹的固体导弹弹射筒进行可靠性评估，从断裂力学的角度，对随机载荷作用下的钢制弹射筒裂纹累积损伤进行了分析和研究，建立了裂纹累积损伤失效物理模型。在此基础上应用蒙特－卡罗方法对算例进行仿真计算，并分析了影响弹射筒可靠性的因素。结果表明，初始裂纹的大小是影响弹射筒可靠性的主要因素，这与实际结果较符合。     

Recent Advances in the Theoretical and Applied Study on Compressible Turbulent Flow over Aerospace Vehicles

This paper focused on the fundamental and applied research of turbulent flows encountered in the hypersonic flight of aerospace vehicles,which take place in the boundary layer and mixing layer.As to the plate boundary layer,LES approach has been used to simulate the flows over compression corners and incident shock waves,revealing that turbulent flows would significantly inhibit the boundary layer separation caused by shock wave-boundary layer interaction(SWBLI).The boundary layer transition over a circular cone has been analyzed through stability analysis and wind-tunnel test,by which the angle-of-attack effect in case of small angle of attack has been studied.Non-linear evolution process and secondary instability structure in the supersonic mixing layer(Mc=0.5) were initially figured out through the study of mixing layer,and knowledge of the flow control mechanism of the boundary layer and mixing enhancement mechanism of the mixing layer has been obtained through this research.Artificial boundary-layer transition technique based on subharmonic resonance has been proposed and applied to the flow control in a scramjet inlet,inhibiting the flow separation of the boundary layer while improving the inlet performance.To guarantee the mixing of kerosene and supersonic airflow in the scramjet combustor,the mixing enhancement method based on subharmonic resonance has been adopted and a concept of combustor with smooth wall and low internal drag has been proposed for ignition and stable combustion.Finally,future turbulence research and technological development of aerospace vehicles is predicted.     

风标式攻角传感器在超声速飞行运载火箭中的应用研究

以运载火箭上的风标式攻角传感器为研究对象,首先运用风洞试验研究其在超声速气流中的静态以及跟随特性。针对箭体常采用的规则旋成体,运用数值仿真分析当地攻角与来流攻角的关系。发现同一位置不同高度(距箭体壁面)当地攻角的变化较小,而同一截面不同周向位置上的影响则较大。在攻角平面内当地攻角不反映来流攻角信息;在垂直于攻角的平面内,受绕流的影响,当地攻角大于来流攻角;在两平面夹角的中心位置,当地攻角大致与来流攻角相当。运用数学分析解算出探测攻角与当地攻角、侧滑角的变换关系,最终获得攻角传感器的探测特性。基于火箭绕流流场的特征以及传感器的探测特性,建议工程应用时在4个象限的中心线上分别布置一个攻角传感器以获得飞行攻角和侧滑角。