排序方式： 共有182条查询结果，搜索用时 15 毫秒
31.
LU Ren MIAO Bingkui WANG Guiqing DAI Deqiu LIN Yangting OUYANG Ziyuan LI Chunlai Institute of Geochemistry Chinese Academy of Sciences Guiyang Guizhou Graduate School Chinese Academy of Sciences Beijing Institute of Geology Geophysics Chinese Academy of Sciences Beijing Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou Guangdong National Astronomical Observatories Chinese Academy of Sciences Beijing 《《地质学报》英文版》2004,78(5):1052-1059
Petrography and mineral chemistry of 24 ordinary chondrites from the Grove Mountains, Antarctica, have been studied in order to identify their chemical-petrographic types. These samples were selected from a total of 4448 Grove Mountains (GRV) meteorites collected during the 19th Chinese Antarctic Research Expedition so as to make an estimation of the large GRV meteorite collection. The chemical-petrographic types of these meteorites are presented below: 1 H3,2 H4, 4 H5, 2 H6, 1 L4, 7 L5, 5 L6, 1 LL4 and 1 LL6. The new data weaken the previous report that unequilibrated ordinary chondrites are unusually abundant in the Grove Mountains region. However, this work confirms significant differences in distribution patterns of chemical-petrographic types between the Grove Mountains and other 相似文献
32.
中国天文学会天文学名词审定委员会 《天文学进展》2008,26(1):95-99
中国天文学会名词审定委员会从1985年开始在<天文学进展>发表天文学名词的推荐译名,到2007年已公布了14批2280个名词.现再推荐第十五批151个名词,其中大多数是近年来出现的天文学新词.希望读者在试用过程中对译名提出改进意见. 相似文献
33.
利用上海地区GPS综合应用网提供的高时空分辨率的双频GPS观测资料,研究了该区域内一电离层不均匀体的产生、消亡过程.首先,采用Kalman滤波的方法改善双频伪距之差的观测精度,并利用参数估计的方法计算该时段内相应的硬件延迟.再根据电离层单层模型,利用GPS双频观测量、测站位置和GPS精密星历,求出GPS信号穿刺点的坐标和垂直方向电离层的电子含量;然后内插并获取其等值线图.等值线图随时间的变化表明,受等离子体湍流的影响,2003年9月8日北京时间9时40分左右在38°N、118°E左右产生了一电离层不均匀体,其尺度大约在50km左右,生存时间大约为5min.受地球重力场和高空风场的影响,该不均匀体向东北方向扩散.然后,利用大气扩散模型,按扩散方程计算分析了该不均匀体可能发生的电离层层区.理论计算表明,该不均匀体发生在电离层扩展F区,高度在350km左右. 相似文献
34.
Experiments on ion implantation were performed in order to better characterize diffusion of noble gases in lunar soil.4He+ at 50 keV with 5×1016 ions/cm2 was implanted into lunar simulants and crystal ilmenite.Helium in the samples was released by stepwise heating experiments.Based on the data,we calculated the helium diffusion coefficient and activation energy.Lunar simulants display similar 4He release patterns in curve shape as lunar soil,but release temperatures are a little lower.This is probably a con... 相似文献
35.
Rui-Xiang Xie Min Wang Yi-Hua YanNational Astronomical Observatories Yunnan Observatory Chinese Academy of Sciences Kunming National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2005,(1)
A rare Type I-like noise storm was observed with the solar radio spectrometers (1.0-2.0 GHz and 2.60-3.8 GHz) at National Astronomical Observatories of China (NAOC) on September 23, 1998. We concentrate on checking the Type I-like noise storm occurred in the decay phase of a Type Ⅳ radio burst. This noise storm consists of many Type I bursts and isolated Type Ⅲ or Type Ⅲ pair bursts. It has a bandwidth of ≤0.5 GHz. The duration of each Type I burst is of the order of 100-300 ms. The total duration is greater than 11 minutes. The circular polarization 相似文献
36.
太阳物理学中的分形和混沌 总被引：1，自引：0，他引：1
对非线性科学的两个重要分支；分形和混沌在太阳物理学中的应用情况作了综述信要内容包括；太阳活动混沌性的揭示；对太阳活动混沌性的可能解释－太阳非线性发电机理论；一些太阳现象的分形描述；耀斑的自组织临界行为研究，最后给出了作者对这一领域工作前景的展望。 相似文献
37.
Zhong-Mu Li Zhan-Wen Han 《中国天文和天体物理学报》2009,9(2)
More than about 50% of stars are in binaries, but most stellar population studies take single star stellar population (ssSSP) models, which do not take binary interactions into account. In fact, the integrated peculiarities of ssSSPs are different from those of stellar populations with binary interactions (bsSSPs). Therefore, it is necessary to investigate the effects of binary interactions on the Lick indices and colors of populations in detail.We show some formulae for calculating the difference between the Lick indices and colors of bsSSPs, and those of ssSSPs. Twenty-five Lick indices and 12 colors are studied in this work. The results can be conveniently used for calculating the effects of binary interactions on stellar population studies and for adding the effects of binary interactions into present ssSSP models. The electronic data and fortran procedures in the paper can be obtained on request from the authors. 相似文献
38.
On the DB gap of white dwarf evolution:effects of hydrogen mass fraction and convective overshooting
Jie Su Yan Li National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming China Graduate University of Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2010,10(3)
We investigate the spectral evolution of white dwarfs by considering the effects of hydrogen mass in the atmosphere and convective overshooting above the convection zone.Our numerical results show that white dwarfs with MH～10-16M⊙ show the DA spectral type between 46000■Teff■26000K and the DO or DB spectral type may appear on either side of this temperature range.White dwarfs with10-15M⊙ appear as DA stars until they cool to Teff～31000K;from then on they will evolve into DB white dwarfs as a result of conve... 相似文献
39.
The simultaneous photometric and spectroscopic observations of the spotted G dwarf AP149 in the young open cluster α Persei are analyzed here.We reconstruct the observed light curves with a two-starspot model by means of a light curve modeling technique,and find that the active regions shift oppositely along longitude on a time scale of one day.Combining with the observational data obtained by other groups,we discuss the evolution of spotted regions in the photosphere,and find that its starspots evolve not ... 相似文献
40.
Bo Wang Zhan-Wen Han National Astronomical Observatories/Yunnan Observatory Chinese Academy of Sciences Kunming China Graduate University of Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2010,10(3)
Type Ia supernovae(SNe Ia)play an important role in the study of cosmic evolution,especially in cosmology.There are several progenitor models for SNe Ia proposed in the past years.By considering the effect of accretion disk instability on the evolution of white dwarf(WD)binaries,we performed detailed binary evolution calculations for the WD+red-giant(RG)channel of SNe Ia,in which a carbon-oxygen WD accretes material from a RG star to increase its mass to the Chandrasekhar mass limit.According to these calcu... 相似文献