舰队弹道导弹计划（1）“北极星”诞生

我们必须保证我们国家的生存．但我们不能仅仅满足于求得生存。我们是一个全球国家，我们的幸福取决于我们的行动自由，我们现在并不能做到自给自足，我们当中的任何一个人都不可能做到一辈子自给自足，即使我们作为一个国家能够使我们自己的生命和利益得以维持，我们的国家又会是个什么样的呢？软弱无力．束手无策，顶多是个中等国家。所以，我们必须关心我们的全球利益。我们全球利益受到的主要军事威胁来自苏联．苏联是另一个唯一真正的全球军事大国。所以我们必须针对苏联，针对苏联的全球利益和行动对我们构成的威胁，衡量我们保持行动自由的能力。 这不是穷兵黩武．不是战争叫嚣，也不是某种随意恐吓的战术。这就是我所理解的为使我们的军事实力达到标准而应采取的最明智和最负责任的立场。[编者按]     

改善小型混响室低频性能的技术

第一节引言本报告给出了小型混响室特性的试验研究结果。在研究过程中,设计、制造和评定了一个容积为135呎~3,用混凝土建造的小型矩形混响室.试验结果表明:当简正方式重叠指数大于1/3时,以统计可靠性、时间均方声压     

The possible origin and persistence of life on Enceladus and detection of biomarkers in the plume

The jets of icy particles and water vapor issuing from the south pole of Enceladus are evidence for activity driven by some geophysical energy source. The vapor has also been shown to contain simple organic compounds, and the south polar terrain is bathed in excess heat coming from below. The source of the ice and vapor, and the mechanisms that accelerate the material into space, remain obscure. However, it is possible that a liquid water environment exists beneath the south polar cap, which may be conducive to life. Several theories for the origin of life on Earth would apply to Enceladus. These are (1) origin in an organic-rich mixture, (2) origin in the redox gradient of a submarine vent, and (3) panspermia. There are three microbial ecosystems on Earth that do not rely on sunlight, oxygen, or organics produced at the surface and, thus, provide analogues for possible ecologies on Enceladus. Two of these ecosystems are found deep in volcanic rock, and the primary productivity is based on the consumption by methanogens of hydrogen produced by rock reactions with water. The third ecosystem is found deep below the surface in South Africa and is based on sulfur-reducing bacteria consuming hydrogen and sulfate, both of which are ultimately produced by radioactive decay. Methane has been detected in the plume of Enceladus and may be biological in origin. An indicator of biological origin may be the ratio of non-methane hydrocarbons to methane, which is very low (0.001) for biological sources but is higher (0.1-0.01) for nonbiological sources. Thus, Cassini's instruments may detect plausible evidence for life by analysis of hydrocarbons in the plume during close encounters.     

Serpentinization and its implications for life on the early Earth and Mars

Ophiolites, sections of ocean crust tectonically displaced onto land, offer significant potential to support chemolithoautotrophic life through the provision of energy and reducing power during aqueous alteration of their highly reduced mineralogies. There is substantial chemical disequilibrium between the primary olivine and pyroxene mineralogy of these ophiolites and the fluids circulating through them. This disequilibrium represents a potential source of chemical energy that could sustain life. Moreover, E (h)-pH conditions resulting from rock- water interactions in ultrabasic rocks are conducive to important abiotic processes antecedent to the origin of life. Serpentinization--the reaction of olivine- and pyroxene-rich rocks with water--produces magnetite, hydroxide, and serpentine minerals, and liberates molecular hydrogen, a source of energy and electrons that can be readily utilized by a broad array of chemosynthetic organisms. These systems are viewed as important analogs for potential early ecosystems on both Earth and Mars, where highly reducing mineralogy was likely widespread in an undifferentiated crust. Secondary phases precipitated during serpentinization have the capability to preserve organic or mineral biosignatures. We describe the petrology and mineral chemistry of an ophiolite-hosted cold spring in northern California and propose criteria to aid in the identification of serpentinizing terranes on Mars that have the potential to harbor chemosynthetic life.     

Detectability of planetary characteristics in disk-averaged spectra II: synthetic spectra and light-curves of earth

Spatially and spectrally resolved models were used to explore the observational sensitivity to changes in atmospheric and surface properties and the detectability of surface biosignatures in the globally averaged spectra and light-curves of the Earth. Compared with previous efforts to characterize the Earth using disk-averaged models, a more comprehensive and realistic treatment of the surface and atmosphere was taken into account here. Our results are presented as a function of viewing geometry and phases at both visible/near-infrared (0.5-1.7 microm) and mid-infrared (5-25 microm) wavelength ranges, applicable to the proposed NASA-Terrestrial Planet Finder visible coronagraph and mid-infrared interferometer and to the ESADarwin mission architectures. Clouds can change the thermal emission by as much as 50% compared with the cloud-free case and increase the visible albedo by up to 500% for completely overcast cases at the dichotomy phase. Depending on the observed phase and their distribution and type, clouds can also significantly alter the spectral shape. Moreover, clouds impact the detectability of surface biosignatures in the visible wavelength range. Modeling the disk-averaged sensitivity to the "red-edge," a distinctive spectral signature of vegetation, showed that Earth's land vegetation could be seen in disk-averaged spectra, even with cloud cover, when the signal was averaged over the daily time scale. We found that vegetation is more readily discriminated from clouds at dichotomy (50% illumination) rather than at full phase. The detectability of phytoplankton was also explored, but was found to be more difficult to detect in the disk-average than land vegetation.     

雷达的进展及基本原理的推广应用

这篇论文是基于2006年10月在中国上海召开的国际雷达会议“雷达-06”上作者的报告完成的。此会议由中国电子协会（CIE）主办，是“五国，五年”系列国际雷达会议（包括中国、英国、澳大利亚、法国和美国）中最近的一次会议。     

采用GMTI雷达跟踪难以确定的动-停-动目标的VS-IMM评估器

提出了可变结构相互作用的多模型(V-IMM)评估器的设计，它采用从机载传感器中获得的地面动目标指示(GMTI)的报告来跟踪难以确定的地面目标。为了避开GMTI传感器的探测，目标采用“动-停-动”模式，即目标在加速之前的某个时候以非常低的速度运动或停止。在这种情况下，当目标的径向速度(沿传感器的视线方向)降至低于某个最小的可探测速度时，传感器就无法探测到目标。在这种条件下，如果使用的传感器不能识别“动-停-动”运动模式，将破坏目标的运动轨迹。本文所提出的VS-IMM评估器就是处理难以确定“动-停-动”目标的运动，在这里，当目标的速度降至某个门限以下，跟踪模型就包括了“停止-目标”模式。采用停止目标模型后，即使在目标检测不连续时仍能保持跟踪的稳定。文中采用仿真的方法来说明设计参数的选择和跟踪器的具体设计。最后，对使用停止目标模式的VS-IMM评估器和传统的：IMM评估器进行性能比较。     

美伊战后回顾4——没有发生的担心：城镇地区作战

在这次由英美联军独自发起的“自由伊拉克”（Operation lraqi Freedom）作战中，城镇地区作战所占比重极大。就传统军事教范观点来看，城镇地区作战向来被视为一项吃力不讨好的繁重任务，因为即便是攻击方拥有绝对战略主动优势，只要守方能够稳住阵脚，利用城镇地区现成的家屋和建筑物善加战场经营，就有机会在攻击者受限于城镇地区地形无法展开和情报受限的情况下造成对手惨重伤亡。从二战时葬送整个德国第六军团的斯大林格勒到让俄罗斯装甲纵队灰头土脸的车臣首府格罗兹尼，血淋淋的教训都明确验证了城镇地区作战的困难。