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As planetary exploration advances, the likelihood of encountering suspected artifacts of astrobiological activity increases, which, it is argued, should be investigated under the auspices of proto-scientific xenoarchaeology. Considering both the unfavorable conditions under which such an investigation may be undertaken (e.g., while observing international planetary protection protocols, utilizing remote sensing techniques in exotic pressure, temperature, chemical, and gravity environments, or adhering to stringent terrestrial biological quarantine and security measures) as well as the demonstrated propensity of the social mind to romanticize or mythologize even the most benign planetary landforms, it is clear that a reactive and poorly preconceived xenoarchaeological methodology will be plagued by inaccuracies, rushed judgments, unrealized bias, misinformation, and erroneous conclusions, along with the negative socio-political impacts that accompany them. Central principles for establishing a rigorous xenoarchaeological methodology are proposed, scientific and technical difficulties are discussed, pertinent international protocols and agreements are reviewed, and sociological and historical considerations are explored. 相似文献
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Sylvie Sahal-Bréchot Milan S. Dimitrijević Nicolas Moreau Nabil Ben Nessib 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
“Stark” broadening theories and calculations have been extensively developed for about 50 years and can now be applied to many needs, especially for accurate spectroscopic diagnostics and modeling. This requires the knowledge of numerous collisional line profiles. Nowadays, the access to such data via an online database becomes essential. STARK-B is a collaborative project between the Astronomical Observatory of Belgrade and the Laboratoire d’Étude du Rayonnement et de la matière en Astrophysique (LERMA). It is a database of calculated widths and shifts of isolated lines of atoms and ions due to electron and ion collisions (impacts). It is devoted to modeling and spectroscopic diagnostics of stellar atmospheres and envelopes, laboratory plasmas, laser equipments and technological plasmas. Hence, the domain of temperatures and densities covered by the tables is wide and depends on the ionization degree of the considered ion. STARK-B has been fully opened since September 2008 and is in free access. 相似文献
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随着新一代航天器的飞速发展,航天器装备多功能化、高度集成化、一体化、微小型化、轻量化趋势不可逆转,电气互连技术将成为影响和制约新研航天器技术迭代的关键因素之一。文章以传统电缆网互连的现状引出航天器互连系统无缆化的需求,总结归纳国内外互连技术实现无缆化的有效途径及措施,并针对现有无缆化互连技术存在的固有缺陷进行分析,从而推论出无缆化互连技术未来将朝着立体柔性光纤传输互连、非接触高效传输互连、MEMS一体化集成互连、组网多维互连等方向发展的趋势,为先进互连技术的发展提供一定的指导意义。 相似文献
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固体火箭发动机工作时,摆动喷管受到伺服力和气动力等载荷的共同作用,在轴向上会产生小幅度的振动,振动频率与燃烧室内腔轴向声频耦合时会造成压力振荡幅值增大,诱发不稳定燃烧,导致燃烧室内压力、燃速不均等情况的出现。应用数值方法研究了摆动喷管轴向激励对燃烧室压力振荡的影响,分析了压力振荡对喷管轴向激励幅值和频率的响应规律,以及燃烧室内的声压分布特征。结果表明,当喷管以燃烧室内腔固有频率做轴向振动时,会诱发燃烧室内的非线性不稳定燃烧,其稳定的极限振幅远高于其他激励频率下压力振荡幅值;喷管振动频率一定时,燃烧室内各点压力振荡幅值随喷管振动幅值增大而线性增大;持续的轴向激励使燃烧室呈现出驻波声场的特征,压力分布不均,波腹处声压达到0.14 MPa,约为燃烧室总压的2%。 相似文献
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喷雾场测试技术研究进展 总被引:2,自引:0,他引:2
喷注器的喷雾质量直接影响推进剂在燃烧室中的燃烧效率。为了准确获得其喷雾特性,以收集法、PDA及PIV为代表的喷雾场测试技术一直在不断发展和完善中,其中PIV技术与数字全息技术相结合发展的DHPIV技术具有较好的应用前景。对近年来的喷雾场测试技术进行了综述,介绍了各种测试技术的原理、特点及其在喷雾场测试中存在的问题。 相似文献
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首先介绍了延迟积分电荷耦合器件(TDICCD)的基本原理,并根据某高分辨率多光谱航天相机定制的一款五光谱TDICCD的输出特性,设计了一种基于五光谱TDICCD的模拟信号发生器,给出了该模拟信号发生器的系统组成,包括图像处理电路、数模转换电路和模拟信号滤波电路。最后通过测试验证了该系统的信号波形、信号噪声和输出图像都满足设计要求,其输出的16通道模拟五光谱TDICCD信号频率可以达到20MHz,噪声控制在10mV以内,具有高精度、多通道和低噪声等特点。目前该模拟信号发生器已成功应用到新一代高分辨率多光谱TDICCD相机成像电路系统的研制中。 相似文献