Geminga脉冲星的COS-B和HEAO-B卫星资料分析     

马宇倩  程凌翔  李惕碚  孙学军  吴枚  宋黎明  马琳 《中国天文和天体物理学报》1992,(4)

本文利用COS-B和HEAO-B卫星资料对Geminga脉冲星进行了守时性分析和谱分析,结果进一步证实了Geminga脉冲星是一颗具有强γ辐射,弱X辐射的γ射线脉冲星.  相似文献   

GENESIS OF THE CUMULATE EUCRITES SERRA DE MAGÉ AND MOORE COUNTY: A GEOCHEMICAL STUDY     

M.-S. Ma  R.A. Schmitt 《Meteoritics & planetary science》1979,14(1):81-89

Major, minor and trace element abundances have been determined by instrumental neutron activation analysis (INAA) in whole rock and plagioclase separates of Serra de Magé (SdM). The whole rock contains 52% normative plagioclase and its chondritic normalized REE abundance pattern shows a large Eu anomaly, dominated by the plagioclase REE distribution, and nearly unfractionated La-Sm and Sm-Lu abundances. The plagioclase separates contained ～ 6% pyroxenes and exhibited a typical plagioclase REE distribution. The REE abundances in the derivative equilibrium magmas from which SdM and Moore County (MC) plagioclases crystallized have been estimated from the plagioclase data and the plagioclase mineral/liquid partition coefficients. The REE distributions in possibly earlier parental magmas were calculated by assuming that various degrees of plagioclase and pigeonite (plagioclase/pigeonite = 1) fractional crystallization had been operative prior to the crystallization of SdM and MC. The calculated La/Sm and Sm/Yb ratios for the earlier magmas are essentially the same as the equilibrium magmas over a wide range (10–95%) of the assumed fractional crystallization. Considering the REE distributions and the Fe/Fe+Mg ratios, calculation shows that there is no simple genetic relationship between MC and SdM via fractional crystallization processes. A hypothesis for the derivation of these cumulate eucrites in the plutonic environment from residual diogenitic liquid, which was produced by the extensive partial melting of an eucritic source material followed by the crystallization of diogenite, also fails to account for the fractionated REE patterns calculated for the equilibrium and the possible parental magmas for either SdM or MC. Equilibrium non-modal partial melting calculations indicate that SdM and MC could be genetically related by a factor ～ 6 difference in the degrees of partial melting from a similar source material. However, this common source material which should contain > 30% high-Ca clinopyroxene and has a chondritic normalized La/Yb ～ 3, is different than that proposed for the non-cumulate eucrites.  相似文献   

The Moho depth in the Canadian Basin and its tectonic implications          下载免费PDF全文

Ma Yuanyuan  Zhao Lihong  Ling Zilong  Yang Mingming  Pang Beibei 《极地研究》1988,31(3):284

  相似文献   

An experimental study on variation of <Emphasis Type="Italic">b</Emphasis> value during deformation of rock samples with different structural models     

Chen Shun-yun  Liu Li-qiang  Ma Sheng-li  Ma Jin 《地震科学（英文版）》2005,18(3):338-344

A preliminary study of b value of rocks with two kinds of structural models has been made on the base of a new acoustic emission recording system. It shows that b value of the sample decreases obviously when the sample with compressive en echelon faults changes into a tensile one after interchange occurs between stress axis σ ₁ and σ ₂. A similar experiment is observed when the sample with tensile en echelon faults changes into that with a bend fault after two segments of the en echelon fault linking up. These facts indicate that the variation of b value may contain the information of the regional dominant structural model. Therefore, b-value analyses could be a new method for studying regional dominant structural models.  相似文献   

Climatological distribution of lightning density observed by satellites in China and its circumjacent regions   总被引：14，自引：1，他引：13  

MA Ming  TAO Shanchang  ZHU Baoyou & LU Weitao School of Earth  Space Sciences  University of Science  Technology of China  Hefei  China 《中国科学D辑(英文版)》2005,48(2):219-229

The 0.5°×0.5°grid resolution distribution of lightning density in China and its circumjacent regions have been analyzed by using the satellite-borne OTD (Apr 1995-Mar 2000) and LIS (Dec 1997-Mar 2003) databases. It is shown that: (i) Firstly, the variability of the lightning density (LD) is particularly pronounced over the different subareas, 9 times greater over the south than the north side of Himalayas Mountains, 2.5 times greater over the eastern than the western area of China. While the maximum and minimum LD are respectively 31.4fl/km2/a (in Guangzhou region) and less than 0.2fl/km2/a (in the desert of western China). Secondly, the LD of China's continent regularly varies with latitude and distance off coast, which is consistent with annual mean precipitation in varying trend. In conclusion, the Qinghai-Tibet Plateau, the China's three-step staircase topography and the latitude are three important factors affecting macro-scale characteristics of the LD distribution, (ii) The regional differences  相似文献   

The crystal structure of (Fe<Subscript>4</Subscript>Cr<Subscript>4</Subscript>Ni)<Subscript>9</Subscript>C<Subscript>4</Subscript>     

Nicheng?ShiEmail author  Zhesheng?Ma  Ming?Xiong  Mingquan?Dai  Wenji?Bai  Qingsong?Fang  Binggang?Yan  Jingsui?Yang 《中国科学D辑(英文版)》2005,48(3):338-345

(Fe4Cr4Ni)9C4 is a metal carbide mineral formed by combination of Fe, Cr and Ni with C. It occurs in a chromite deposit in the Luobusha ophiolite, Tibet. Based on the determination of its crystal structure, the empirical formula is (Fe4.12Cr3.84Ni0.96)8.92C3.70 and the simplified formula is (Fe4Cr4Ni)4C9. The mineral is hexagonal with a = 1.38392(2) nm, c = 0.44690(9) nm, pace group P63 m c, Z=6 and the calculated specific gravity Dx = 7.089 g/cm3. Fe, Cr and Ni occupy different crystallographic sites and their coordination numbers are approximately 12, forming an alternate stacking sequence of flat and puckered layers along the c axis. Some metallic atoms have a defect structure. The interatomic distances of Fe, Cr and Ni are 0.2525-0.2666 nm, and the distances between Fe, Cr, Ni and C are 0.1893-0.2169 nm. The coordination number of carbon is 6. It occurs in interstices of the metallic atoms Fe, Cr and Ni to form trigonalprismatically coordinated polyhedra. These coordination polyhedra are linked with each other via shared corners or shared edges into a new type of metal carbide structure.  相似文献   

应用塑性图对陕西特殊土的判别     

马桂芝 《地球科学与环境学报》1995,(2)

塑性图是由卡萨格兰德（Ａ·Ｃａｓａｇｒａｎｄｅ）于１９４２年首次提出的，该图将阿太量（Ａ·Ａｅｔｅｒｂｅｒｇ）界限（液限、塑限）应用于土质分类．本文根据塑性图判别理论并应用塑性图，对陕西省特殊土（黄土、三趾马红土、膨胀土等）进行了判别，结果为黄土位于ＣＬＹ区，三趾马红土和膨胀土位于ＣＨＥ区，其效果较好，达到了分类的目的．  相似文献   

面向Internet的农业气象产量动态预报   总被引：2，自引：1，他引：1  

王石立  马玉平  刘文泉  林日暖  庄立伟 《气象》2004,30(4):42-45

针对信息时代Internet网上用户对产量预报动态查询的需求 ,探讨了面向Inter net的农业气象产量预报的解决方案。试验结果表明 ,由于作物生长发育和产量形成是一个光、温、水、土条件长期、综合作用 ,生物量长期累积的过程 ,因此利用积分回归方法 ,考虑全生育期光、温、水气象因子的综合影响 ,根据已出现的天气实况 ,在假定后期天气条件正常的情况下 ,有可能预测出未来产量的趋势。随着天气实况的逐一出现 ,后期的预报结果可望逐步接近实际值。统计检验和试报结果误差均在允许范围内。  相似文献   

中国大陆7级强震前地下流体前兆时空特征   总被引：5，自引：0，他引：5  

晏锐  黄辅琼  顾瑾平 《地震》2004,24(1):126-131

对中国大陆1969年以来11次7级强震前地下流体前兆观测资料分阶段进行统计分析,并选用雷达图描述了中国大陆7级强震前地下流体前兆异常的时空特征,认为其特征主要表现在：异常出现时间上的阶段性与不均匀性,中长期趋势性异常分散,短临异常相对集中,且各占总异常比例的50％左右;震前异常集中在一定的范围内,并沿活动断裂呈现出一定的集中性;中长期趋势异常较早出现在震源区附近,并呈现出由震源区向外围扩散-收缩-扩散-收缩的过程,特别是进入短临阶段后,异常向震源区收缩的趋势更为明显;在震源区(或在距震源较近的范围内)异常所占的比例大,远离震源区所占比例小,且有由震源区向外围逐渐减小的趋势。  相似文献   

Co-seismic ground deformation and source parameters of Mani M7.9 earthquake inferred from spaceborne D-InSAR observation data   总被引：4，自引：0，他引：4  

SHAN Xinjian  MA Jin  WANG Changlin  LIU Jiahang  SONG Xiaoyu & ZHANG Guifang .Institute of Geology  Laboratory of Tectonophysics  China Seismological Bureau  Beijing  China  .Institute of Remote Sensing Application  Chinese Academy of Sciences  Beijing  China 《中国科学D辑(英文版)》2004,47(6):481-488

In recent ten years, Differential Interferometric Synthetic Aperture Radar (D-InSAR) has become a major technique of space-based geodesy together with GPS, VLBI and SLR. Interferometric Synthetic Aper-ture Radar (InSAR) has many advantages, such as all-weather, all-time, strong stability and dynamic survey property, and no requirements for ground sta-tions. In particular, the surveying results by InSAR can cover a large range of the ground deformation field in succession and has gr…  相似文献