排序方式: 共有45条查询结果,搜索用时 15 毫秒
31.
Kordyum EL Nedukha EM Popova AF Sidorenko PG Fomicheva VM Sytnik KM 《Acta Astronautica》1983,10(4):225-228
On the basis of using of modern methods of cytological analysis the cell growth peculiarities, reproduction and structure of plant cells of different level organisation (unicellular algae, mosses, angiosperms, cell cultures of higher factors--weightlessness, hypogravity, magnetic fields of various intensity, vibration and acceleration were cleared. It is shown that many discovered biological effects of space flight are connected with the degree of complexity of the object organisation and intensified with the increasing duration of influence. 相似文献
32.
33.
信息维数是从信息量的角度来度量复杂网络分形特性的常用指标。在现有的基于盒子覆盖法的复杂网络信息维数概念上,进一步考虑网络节点间的差异性,将每个盒子包含信息的概率定义为该盒子内节点度的总和与网络中所有节点度的总和之间的比值,提出了一种新的复杂网络信息维数计算方法。在5个真实网络数据集上进行分形分析,并将分析结果与利用基于盒子覆盖法的复杂网络信息维数法得到的结果以及利用盒维数法得到的结果进行对比。研究结果表明:新的信息维数法计算所得的信息维数值与网络的盒维数值相近,并且该方法同样能够较好的度量实际网络的分形特性。 相似文献
34.
天津滨海国际机场创建于日伪时期,其前身是天津张贵庄机场,1952年改扩建是建国后我国改建的第一个机场,本机场先后共经过四次较大规模的改扩建。除1996-1998年,扩建了10万m^2的停机坪,增加一条快速出口滑行道,并对助航灯光、34号跑道仪表着陆系统及配套设施进行了改造外,原有跑道系统是在1974年扩建的基础上形成的。有一条跑道、一条平行滑行道、两条端联络道、两条垂直联络道和一条快速出口滑行道。 相似文献
35.
36.
当今喷气燃料研究的几个热点问题 总被引:6,自引:0,他引:6
现代空战的实践证明,消耗物资中喷气燃料占第一位.随着空军的发展,各国更加重视喷气燃料的研究工作.针对高技术的局部战争的特点,进入90年代后,对喷气燃料的研究集中在以下几个问题上.外场喷气燃料质量监控系统的研究由于空军的特点,对油料质量的要求非常严格,在任何条件下,都 相似文献
37.
Microbial populations in Antarctic permafrost: biodiversity, state, age, and implication for astrobiology 总被引:1,自引:0,他引:1
Gilichinsky DA Wilson GS Friedmann EI McKay CP Sletten RS Rivkina EM Vishnivetskaya TA Erokhina LG Ivanushkina NE Kochkina GA Shcherbakova VA Soina VS Spirina EV Vorobyova EA Fyodorov-Davydov DG Hallet B Ozerskaya SM Sorokovikov VA Laurinavichyus KS Shatilovich AV Chanton JP Ostroumov VE Tiedje JM 《Astrobiology》2007,7(2):275-311
Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one. Up to 10(4) viable cells/g, whose age presumably corresponds to the longevity of the permanently frozen state of the sediments, have been isolated from Antarctic permafrost. Along with the microbes, metabolic by-products are preserved. This presumed natural cryopreservation makes it possible to observe what may be the oldest microbial communities on Earth. Here, we describe the Antarctic permafrost habitat and biodiversity and provide a model for martian ecosystems. 相似文献
38.
39.
40.
国航天津分公司飞行部综合楼工程位于天津市东丽区滨海国际机场国航天津分公司飞行部院内,占地5696.75m^2,共分主楼、食堂、室外连廊、动力房等多个子单位工程,建筑面积共计7661m^2,建筑物最大高度17.85m。主楼、食堂、室外连廊为框架结构,动力房为砖混结构。主楼、食堂、室外连廊 相似文献