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金牛座是冬季星空的代表星座,大约11月的傍晚之后,它便出现于东方天空,1月到2月它横越过头顶方向,直到4月的傍晚才降到西方天空.由于金牛座出现的时间长,升空的位置又相当高,因此,很利于大家观赏.在金牛座的"牛眼"附近有一颗闪耀着橙色光的亮星,中名毕宿五,学名金牛座α星,是全天21颗最亮恒星之一,在<中国大百科全书·天文学卷·最亮星表>中排名第13位.在毕宿五附近有7颗小星,与毕宿五一起排列成Y字形,这是著名的毕星团.由毕星团向西北方向寻去,可以找到6~7小星,这是金牛座的另一个著名星团--昴星团.毕宿五、毕星团和昴星团这三个天体就是本文的主角. 相似文献
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六月二十一日至七月二十日的生辰星座是巨蟹座.黄道十二宫1元硬币中的巨蟹座钱币正面与其他11枚一样为英国女王伊丽莎白二世带大王冠头像,下方为英文1美元,右方为英文库克群岛,左方为英文伊丽莎白二世;背面外圈为巨蟹图案,内圈为一小洞,内放巨蟹星座幸运宝石翡翠. 相似文献
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生辰星座的金牛座在4月21日~5月20日.黄道十二宫1元硬币中的金牛座钱币正面与其他11枚一样是英国女王伊丽莎白二世的大王冠头像,钱币背面的外圈为希腊神话中金牛星座图案,内圈为一小洞,内放金牛星座幸运宝石蓝宝石,下方是金牛座的符号(¤). 相似文献
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《世界航空航天博览》2005,(5):76-77
中俄边界勘定概况 中国同俄罗斯有着漫长的边界线。中俄共同边界总长4209.3千米,其中,陆界650.3千米,江河界3489千米,湖泊界70千米。从地理上看,中俄东段边界线主要以河流为界,大体上由额尔古纳河、黑龙江和乌苏里江构成。此次中俄国界东段补充协定涉及的黑瞎子岛和阿巴盖图洲渚,前者为黑龙江与乌苏里江夹角之间的一个小三角洲,处在中国的东北角。 相似文献
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反舰导弹平面机动突防策略的优化设计 总被引:1,自引:1,他引:0
研究了遗传算法在反舰导弹综合突防策略的优化设计方面的应用.反舰导弹的综合突防包括若干个相互承接的环节,首先将反舰导弹的综合突防概率优化问题分解为各个环节突防的条件概率的优化问题,复杂事件得到简化.反舰导弹为了提高突防概率必须做机动,每个环节对应的机动参数取值在一定范围内变化,每个环节的突防概率受到对应的这组参数的影响.选用遗传算法对突防参数进行优化设计.用遗传算法对反舰导弹各个突防环节进行优化设计,找出使每个突防环节突防概率最大的一组参数,进而得到综合突防最优机动参数组合,使反舰导弹的综合突防概率最大. 相似文献
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M. Chernetskiy I. PaskoA. Shevyrnogov N. SlyusarA. Khodyayev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Remote sensing applications have greatly enhanced ability to monitor and manage in the areas of forestry. Accurate measurements of regional and global scale vegetation dynamics (phenology) are required to improve models and understanding of inter-annual variability in terrestrial ecosystem carbon exchange and climate–biosphere interactions. Study of vegetation phenology is required for understanding of variability in ecosystem. In this paper, monitoring of vegetation dynamics using time series of satellite data is presented. Vegetation variability (vegetation rate) in different topoclimatic areas is investigated. Original software using IDL interactive language for processing of satellite long-term data series was developed. To investigate growth dynamics vegetation rate inferred from remote sensing was used. All estimations based on annual time series of Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. Vegetation rate for Enhanced Vegetation Index (EVI) and Normalized Difference Vegetation Index (NDVI) was calculated using MODIS data. The time series covers spring seasons of each of 9 years, from 2000 to 2008. Comparison of EVI and NDVI derived growth rates has shown that NDVI derived rates reveal spatial structure better. Using long-term data of vegetation rates variance was estimated that helps to reveal areas with anomalous growth rate. Such estimation shows sensitivity degree of different areas to different topoclimatic conditions. Woods of heights depend on spatial topoclimatic variability unlike woods of lowlands. Principal components analysis shows vegetation with different rate conditions. Also it reveals vegetation of same type in areas with different conditions. It was demonstrated that using of methods for estimating the dynamic state of vegetation based on remote sensing data enables successful monitoring of vegetation phenology. 相似文献
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The use of an electric field in increasing the resistance of plants to the action of unfavorable space flight factors. 总被引:2,自引:0,他引:2
G Nechitailo A Gordeev 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2004,34(7):1562-1565
The key role in increasing the resistance of plants to unfavorable space flight factors is assigned to biomembranes of root cells. It is these biomembranes in which numerous biochemical and biophysical processes determining the adaptive capacity of plant organisms occur. In the initial period of exposure to unfavorable space flight factors the adaptation reactions of the plant organism undoubtedly increase its resistance. But the intensification of removal of H+ ions through the plasmalemma with an increase of the external influence sharply raises the quantity of cations leaving the cell, which leads to the accumulation of a considerable quantity of intracellular negative charges. These charges together with negative charges built in the membrane force protons to concentrate on the external surface of the membrane. Since protons have a very strong electric field, they form such a charge of which the electric field is about from several to hundreds of V/cm. The concentration of positive charges of protons entails the formation of a double electric field which extremely impedes the diffusion of other ions. Thus, a proton barrier is formed. Its length can be very considerable due to which the whole process of transmembrane energy and mass-transfer is disturbed. The proton barrier is easily destroyed by a weak electric field created in the root zone. In experiments on electrostimulation of different plants under space flight conditions at the orbital station MIR the absorption of nutrient elements by the root system increased to the optimal level, the ratio of physiologically active substances in the rhizosphere was normalized, the content of chlorophyll, carotin, and ascorbic acid in leaves corresponded to the ground-based control. Understanding of the mechanism of formation of a proton barrier on the plasmalemma of root cells as a result of the response of plants to the negative action of external factors (microgravity) is of great importance. It allows the possibility of life support of the vegetable kingdom in extreme conditions to be estimated in a new way. 相似文献
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Neta A. Bahcall 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,3(10-12)
The spatial distribution of a complete redshift sample of nearby rich clusters of galaxies is studied. Strong superclustering, extending to very large scales (100h−1Mpc), is observed in the cluster distribution. In particular, we determined and discuss below the following studies:I. The spatial correlation function of rich clusters of galaxies.II. The construction of a complete catalog of superclusters and a study of their growth (percolation).III. The finding of large-scale superclusters surrounding the giant galaxy void in Bootes.IV. The finding of a 300 Mpc void of rich clusters of galaxies.All the above studies provide evidence for the existence of large-scale structure in the universe, and reveal some of its characteristics. These findings are of importance to models of the formation of galaxies and structure in the universe. 相似文献
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气泡雾化喷嘴的试验研究 总被引:3,自引:0,他引:3
进行了组不同结构形式的气泡雾化喷嘴的试验研究,初步试验结果表明:这种新型喷嘴对液体介质粘度不敏感,在小气液比条件下获得了很好的雾化效果,雾化性能明显优于从国外引进的某些空气雾化喷嘴,该成果已于1993年2月7日被授予中华人民共和国实用型专利。 相似文献
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I Mann T Mukai H Okamoto 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1995,16(2):37-40
The analysis of interplanetary dust shows that the majority of particles in out-of-ecliptic regions comes from comets and also that near solar dust, in the ecliptic regions, results most probably largely from comets. The intense radiation flux in the solar vicinity is expected to cause strong modifications in the material composition and surface structure of interplanetary dust particles and hence the analysis of near solar dust provides interesting insights into the evolution of meteoritic, especially cometary materials. Because of the lack of in-situ measurements our present knowledge concerning these processes derives from remote sensing, i.e. observations of the solar F-corona. In particular these are observations of albedo, polarization and colour temperature given in terms of average particle properties. For example the analysis of near infra-red F-corona data points to the existence of a strong component of irregularly structured silicate particles, most probably of cometary origin. The data may indicate a subsequent sublimation of different particles or different constituents of the particles. Here we compare particle properties derived from F-corona observations with model calculations of single particle properties and discuss perspectives of future analysis of cometary dust in the interplanetary cloud. 相似文献
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P Waliszewski J Konarski 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2001,28(4):545-548
Cell is a supramolecular dynamic network. Screening of tissue-specific cDNA library and results of Relative RT-PCR indicate that the relationship between genotype, (i.e., dynamic network of genes and their protein regulatory elements) and phenotype is non-bijective, and mendelian inheritance is a special case only. This implies non-linearity, complexity, and quasi-determinism, (i.e., co-existence of deterministic and non-deterministic events) of dynamic cellular network; prerequisite conditions for the existence of fractal structure. Indeed, the box counting method reveals that morphological patterns of the higher order, such as gland-like structures or populations of differentiating cancer cells possess fractal dimension and self-similarity. Since fractal space is not filled out randomly, a variety of morphological patterns of functional states arises. The expansion coefficient characterizes evolution of fractal dynamics. The coefficient indicates what kind of interactions occurs between cells, and how far from the limiting integer dimension of the Euclidean space the expanding population of cells is. We conclude that cellular phenomena occur in the fractal space; aggregation of cells is a supracollective phenomenon (expansion coefficient > 0), and differentiation is a collective one (expansion coefficient < 0). Fractal dimension or self-similarity are lost during tumor progression. The existence of fractal structure in a complex tissue system denotes that dynamic cellular phenomena generate an attractor with the appropriate organization of space-time. And vice versa, this attractor sets up physical limits for cellular phenomena during their interactions with various fields. This relationship can help to understand the emergence of extraterrestial forms of life. Although those forms can be composed of non-carbon molecules, fractal structure appears to be the common feature of all interactive biosystems. 相似文献
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载人运输飞船流体回路方案研究 总被引:4,自引:1,他引:3
流体回路是载人运输飞船热控分系统的重要组成部分,结合飞船所采取的其他热控措施,流体回路必须满足各种可能出现的热工况要求,同时尽量少占用飞船的资源。在进行分析和比较的基础上,确定流体回路的方案和系统配置,结合对接目标的热设计,重点解决与目标停靠期间的热控问题。文中介绍了载人运输飞船流体回路的主要设计要求及考虑重点,在能量平衡分析的基础上设计了两种流体回路方案,并进行了热分析计算和性能比较,对流体工质的选择也提出了建议。 相似文献
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R. Z. Sagdeev S. I. Anisimov A. A. Galeev V. D. Shapiro V. I. Shevchenko 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(12):133-143
The motion of dust particles near Halley Comet is studied and the probability of dust impacts with the spacecraft in case of the VEGA (Venus-Halley)- project is determined. The formation of a crater due to a particle impact with the dust shield is considered and the necessity for using a dual-sheet bumper shield is substantiated. The thickness of a front sheet that plays a role of the particle evaporator is estimated theoretically. The numerical experiment is carried out that simulates the dynamics of collision and evaporation of a particle. Three factors causing perforations of the rear sheet are discussed, i.e. dust penetrated through holes in the front sheet, gas jets and spall fragments of the front-sheet. The consideration of these factors makes it possible to estimate basic parameters of the dual-sheet bumper shield. Flexural vibrations of the front sheet under action of the reverse gaseous jet from the rear sheet are discussed that can affect essentially the shield strength. The perturbing effect of the dust and gas fluxes on the spacecraft is studied. 相似文献
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杨维垣 《中国空间科学技术》1993,13(1):25-32
在卫星研制工作中可采用11种接口数据单加强设备的接口数据管理工作。它们是:机械特性,设备示意图,热特性,热特性示意图,电源功率,接口电特性,电气方块图,接插件表,接插件接点分配表,遥测表,遥控指令表。它们包含了可以全面反映设备接口特性的各项数据。使用它们可以进行严格的状态管理并保证接口数据协调工作的质量。文内介绍了这些数据单的具体内容以及使用中的问题。 相似文献