无人战斗机述论

2 推动无人战斗机发展的背景与原由(略)3无人战斗机的战术技术要求与作战特点3.1 对无人战斗机特殊的战术技术要求 据悉1997年初,在美国的中国湖城,美军方召集200多名专家历时多日专题研讨UCAV的战术技术要求问题,研究报告未见发表,但近些年文刊上也陆续有这方面的讨论(主要是针对对地攻击型UCAV的战技要求),其要点归纳如下:     

对复杂平面连杆机构运动分析的研究

本文提出了用转化机构法进行单自由度复杂平面连杆机构的运动分析.基本思想是通过改变机构的原动件或机架或同时改变原动件和机架,以简化机构的运动分析.这种方法对常见的平面复杂连杆机构的运动分析非常有效,无需进行复杂的试凑或迭代.同时本文提出的这种解法有较为广泛的意义,对加深认识机构的组成以及对机构其它问题的研究都是+分重要的.     

PDM技术在机械可靠性设计分析中的应用研究

多领域工具集成是复杂产品虚拟样机设计仿真需要解决的技术问题之一.提出了一个面向服务集成、具有良好开放性、基于标准的、即插即用的机械可靠性设计分析多领域工具集成平台,以及基于产品数据管理(PDM)技术的机械可靠性设计分析虚拟样机体系结构.讨论了如何面向模型数据管理实现设计和协同分析过程中CAD/CAE工具与PDM的综合集成.最后,以某空间结构锁系可靠性设计分析为例,简要介绍了基于CAD/CAE工具的机械可靠性一体化设计、分析方案,以及如何采用应用封装技术实现基于PDM的机械产品可靠性协同建模和分析.     

Changes in radio emission from PSR J0737–3039B

The double pulsar system, J0737–3039, provides a unique probe of a pulsar magnetosphere due to its edge-on viewing geometry, a tight orbit and a significant rate of advance of the angle of periastron. In this paper, we report on the changes in radio emission from the long period pulsar in this system, J0737–3039B, over a period of 9 months. Observations of this system with Giant Metrewave Radio Telescope (GMRT) show that the duration of the first bright phase of the pulsar centered at 210° orbital longitude from the ascending node is shrinking. These observations will be useful to constrain the proposed models for this system.     

Geosynchronous satellites expanding a future GNSS satellite constellation: A precise orbit determination study

The integration of geosynchronous orbit (GSO) satellites in Global Navigation Satellite Systems (GNSS) is mostly discussed to enable a regional enhancement for tracking. But how do GSO satellites affect the orbit determination of the rest of the constellation? How accurately can these orbits be determined in a future GNSS tracking scenario with optical links? In this simulation study we analyze the benefit of GSO satellites as an expansion of a MEO (Medium Earth Orbit) satellite constellation – we selected the Galileo satellite constellation – for MEO Precise Orbit Determination (POD). We address not only the impact on POD of MEO satellites but also the possibility to precisely determine the GSO satellites – geostationary orbits (GEO) and inclined geosynchronous orbits (IGSO) – in such an expanded MEO constellation. In addition to GNSS microwave observations, we analyze the influence of different optical links between the participating entities: Optical two-way Inter-Satellite Links (OISL) and ground-space oriented Optical Two-Way Links (OTWL). These optical measurements together with the GNSS microwave observations give a remarkable benefit for the POD capability. In the case of GNSS and OTWL, we simulate the measurements with regard to a network of 16 ground stations. We pay great attention to the simulation of systematic effects of all measurement techniques. We discuss the influence on the systematic errors as well as the formal orbit uncertainties. A MEO constellation expanded with GSO satellites as well as the use of optical links together with GNSS observations not only improves the MEO satellite orbits but also the GSOs to a great extent.     

Time variations of the total electron content in the Southeast Asian equatorial ionization anomaly for the period 2006–2011

This study presents the time variations of the total electron content in the South East Asian equatorial ionization anomaly. The time variation of the TEC is analyzed through the period 2006–2011 by using a latitudinal chain of GPS stations extending in the northern and southern hemisphere. The data shows that the shape of the diurnal variation of the TEC depends on the latitude: a plateau is observed at the stations near the equator and a Gaussian at the station distant from the equator. We observe a semiannual pattern in all the stations with maxima at equinox. In both hemispheres, the amplitude of the crest is larger in spring than autumn from 2006 to 2008 and smaller in spring than in autumn from 2009 to 2011. We also observe an asymmetry between the amplitude and the position of the two crests of ionization. There is a very high level of correlation between the amplitude of the TEC at the two crests and the sunspot number: ∼0.88. During the deep solar minimum 2008–2009, the amplitude of crests of ionization becomes small during several months in summer and winter. The results show that both crests move significantly equatorward in winter than other seasons and there is a tendency for both crests to appear earlier in winter and later in summer.     

Thermal Radiation Processes

We discuss the different physical processes that are important to understand the thermal X-ray emission and absorption spectra of the diffuse gas in clusters of galaxies and the warm-hot intergalactic medium. The ionisation balance, line and continuum emission and absorption properties are reviewed and several practical examples are given that illustrate the most important diagnostic features in the X-ray spectra.     

论战术数据链的基本特征

文章在强调战场资源有效共享与作战任务优化匹配的基础上,描述了战术数据链的涵义及其功能模型,探讨了其战术专用、消息标准、态势统一、协同模式、智能网络及控制规范等6个基本特征,提出了发展的建议。     

可变编码调制在遥感卫星中的应用效能研究

随着遥感卫星观测数据量的日益增加，卫星数据传输能力已成为制约遥感卫星使用效能的瓶颈因素。为充分利用近地遥感卫星数据传输的链路资源，采用可变编码调制（VCM）技术，通过对星地数传信道条件的动态评估，在保证链路传输误码率和链路余量的前提下，自适应地进行当前信道条件下的最优编码调制方式切换，充分利用系统链路余量，提高卫星星地数据传输效能。利用该方法，对VCM数传链路效能进行仿真分析，与相同符号速率的固定编码调制（CCM）体制相比，VCM传输效能平均提升42.1%，可为遥感卫星的数传通道设计提供借鉴。     

The INTEGRAL view of Gamma-Ray Bursts

After more than six and half years in orbit, the ESA space observatory INTEGRAL has provided new, exciting results in the soft gamma-ray energy range (from a few keV to a few MeV). With the discovery of about 700 hard X-Ray sources, it has changed our previous view of a sky composed of peculiar and “monster” sources. The new high energy sky is in fact full of a large variety of normal, very energetic emitters, characterized by new accretion and acceleration processes (see also IBIS cat4 (Bird et al., 2010). At the same time, about one GRB/month is detected and imaged by the two main gamma-ray instruments on board: IBIS and SPI. In this paper, we review the major achievements of the INTEGRAL observatory in the field of Gamma-Ray Bursts. We summarize the global properties of Gamma-Ray Bursts detected by INTEGRAL, with respect to their duration, spectral index, and peak flux distributions. We recall INTEGRAL results on the spectral lag analysis, showing how long-lag GRBs appear to form a separate population at low peak fluxes. We review the outcome of polarisation studies performed by using INTEGRAL data. Finally, concerning single GRB studies, we highlight the properties of particularly interesting Gamma-Ray Bursts in the INTEGRAL sample.