A model of low-frequency quasi-periodic oscillations in black hole X-ray binaries     

Zhi-Yun Wang  Chang-Yin Huang  Ding-Xiong Wang  Jiu-Zhou Wang 《天体物理学报》2012,(6):661-670

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恒星级黑洞的观测证认研究进展     

张双南 《天文学进展》2012,30(1):1-16

具有不同质量的恒星在耗尽其热核能源后,最终可能会坍缩成为性质完全不同的致密天体,如白矮星、中子星或者黑洞。从20世纪30年代起,黑洞的观测及其证认一直是天体物理学的研究热点之一。首先简要地回顾了恒星级黑洞的形成及其候选天体的研究历史;然后介绍了如何从观测上证认恒星级黑洞:接着详细讨论了恒星级黑洞的质量和自转参数的测量方法;最后介绍恒星级黑洞观测及其证认的最新研究进展,并做出结论:目前已经有充分的证据宣告在部分吸积X射线双星中存在恒星级黑洞。  相似文献   

湘中安化黑色页岩土壤玉米的元素地球化学分析   总被引：1，自引：0，他引：1  

杨克苏  彭渤  刘茜  余昌训  唐晓燕  谢淑容  谭长银 《矿物岩石地球化学通报》2012,31(3):236-248

利用等离子质谱(ICP-MS)等分析技术,对产于安化东坪、烟溪黑色页岩土壤上的玉米进行元素地球化学分析.结果.表明:尽管东坪、烟溪黑色页岩土壤重金属元素富集的程度及其元素组合特征明显不同,但生长在其上的玉米有相似的主量元素和重金属元素的富集特征.玉米中Cd、Cr、Sc、Tl、Zn等重金属相对富集,以Cd的富集尤为明显;而Ba、Co、Cu、Fe、Mo、Ni、Pb、Sb、U、V等重金属相对亏损.黑色页岩土壤重金属污染的环境地球化学效应表现为Sc、Cr、Cd、Tl等生物毒性重金属元素在玉米中富集,而Ba、V、Co、Ni、Mo、Rb、Sr等生物必需微量金属在玉米中亏损.  相似文献   

Jurassic Black Shales Facies from Qiangtang Basin (Northern Tibet):Rare Earth and Trace Elements for Paleoceanographic Implications   总被引：1，自引：0，他引：1  

CHEN Lan  YI Haisheng  TSAI Louis Loung-Yie  XU Guiwen  DA Xuejuan  LIN Andrew Tien-Shun 《《地质学报》英文版》2013,87(2):540-554

The Biluo Co and Amdo 114 station, northern Tibet, cropping out the Early Toarcian and Middle-Late Tithonian (Jurassic) organic-rich black shales, have been a focus to petroleum geologists in discussing their oil-producing potential. This paper first reports the trace elements and rare earth elements to discuss the paleoenvironments, redox conditions and sedimentary mechanisms of those black shales. Both sections exhibit variation in trace element abundances with concentrations <0.1 ppm to 760 ppm, mostly enriched in V, Cr, Ni, Cu, Zn, Mo, Ba and U. Element ratios of Ni/Co, V/Cr, U/Th and V/(V+Ni) plus U were used to identify redox conditions. The shale-normalized rare earth element (REE) patterns are characterized by the flat-shale type with instable Ce anomalies and very weekly positive Eu anomalies. Positive Ceanom values are significant with values varying between –0.064 and 0.029 in Biluo Co, which may be interpreted as release of REE and input of riverine terrestrial matter with rich Ce (resulting in pH change) during the anoxic conditions. In the middle parts of Amdo 114 station, distinct negative Ceanom values are observed (?0.238 to ?0.111) and associated surface water warming were interpreted as being related to a major sea level rise. In contrast, the formation of the black shales in the lower and upper part of the studied succession took place during a cooler (Ceanom values >–0.10), lower surface water productivity, and lower sea-level stage. Thus, we emphasize the role of different factors that control the formation of local and regional black shales. The most important factors are sea-level fluctuations and increasing productivity.  相似文献   

矿山对生态环境的“黑洞与白洞”效应假说     

赵文廷 《四川地质学报》2013,(3):325-327

矿山就是矿产资源开发建设与施工在自然生态面上挖除了一块,使完整的自然生态面出现一个“空洞”,它就像宇宙中“黑洞”与“白洞”干扰和影响宇宙场一样,对自然生态及其环境有很大的破坏作用。矿山对生态环境是否存在“黑洞与白洞”效应？单个矿山生态环境有怎样的“黑洞与白洞”效应？矿山集群对生态环境有怎样的“黑洞与白洞”效应？矿山生态环境可以人为优化吗？对这些问题的探索与研究对矿山生态环境的总治理与保护具有重要意义。  相似文献   

陕西省商南县穆家河钒矿床地质特征及钒的赋存状态研究     

李赛赛 《地质与勘探》2013,49(4):609-619

穆家河钒矿床产于南秦岭下寒武统水沟口组第一岩性段,含矿岩石主要为硅质岩夹( 炭质) 泥岩。钒矿体严格受层位控制,呈层状、似层状产出,沿走向、倾向上延伸均较稳定。通过物相分析、X - 射线衍射测试及电子探针分析,穆家河钒矿床中钒主要有三种赋存状态: 存在于钒云母中、以胶体状态存在的 V - Fe 氧化物、以氧化物集合体形式存在的 V - Ti,其中以钒云母为主。①钒云母的标型为2M1 型,化学式为 K( Al,V)2( Si,Al)4O10( OH)2或( K,Ba,Na)0. 75( Al,Mg,Cr,V)2( Si,Al,V)4O10( OH,O)2,呈片状、条带状产出,其 V2O5含量最高可达到 22. 68%,钒以类质同相形式替代云母中的铝; ②胶体状态存在的 V - Fe 氧化物,呈草莓状、圆球状、星点状、环状产出,颗粒直径小于 10μm,化学组成主要为 V、Fe、O,其中含钒最高可达到10. 09%,不含水,为胶体老化后形成的非晶质体; ③ V - Ti 氧化物集合体呈浸染状、星散状分布于岩石基质中,它最初是以胶体形式沉积,在后期成岩及地质演化过程中,其中钛的氧化物结晶形成锐钛矿、板钛矿等。  相似文献   

东昆仑东段杏树沟金矿化带内石英钠长斑岩LA-ICP-MS锆石U-Pb年龄及围岩地球化学特征          下载免费PDF全文

时超  李荣社  何世平  于浦生  王超  潘术娟  张海迪 《地质科学》2013,(4):984-996

东昆仑成矿带是我国西部重大成(找)矿潜力的贵金属-有色金属成矿带。野外调查期间,对东昆仑东段都兰县诺木洪南下石炭统哈拉郭勒组(C₁h)杏树沟金矿(化)点进行了年代学及围岩地球化学研究。通过高精度LA-ICP-MS锆石微区原位U-Pb同位素测年,获得金矿(化)点的石英钠长斑岩 ²⁰⁶Pb/²³⁸U 年龄加权平均值为243.4±1.9 Ma,确定金矿(化)发生在早三叠世。地球化学分析表明,杏树沟金矿(化)点围岩(安山玄武岩)具有高Al₂O₃、Na₂O,低TiO₂、K₂O的特征。在Zr/TiO₂-Nb/Y图解中全部样品均落入安山玄武岩区,TFeO/Mg-SiO₂图解中全部样品均落入拉斑系列区域中,属于拉斑系列玄武岩。稀土和微量元素显示其富集LREE、LILE和部分HFSE,Nb、Ta、Nd、Zr、Hf相对亏损,REE表现为LREE/HREE明显分离的分配模式,从多种判别图解综合分析,认为该套火山岩形成于大陆裂谷环境中。  相似文献   

The nature and origin of pigments in black opal from Lightning Ridge,New South Wales,Australia     

J. R. Herrmann  R. Maas  P. F. Rey  S. P. Best 《Australian Journal of Earth Sciences》2013,60(7):1027-1039

Abstract

Black opal (opal-AG) owes its dark coloration to a fine-grained pigment commonly inferred to be mainly carbon, yet chemical compositions for black opals suggest there may be additional components. Here we search for such components in pigment concentrates prepared by dissolving black opal nodules (nobbies) from Lightning Ridge (NSW) in hydrofluoric acid, using electron microscopy (scanning electron microscopy, transmission electron microscopy), X-ray diffraction and laser-ablation ICP-MS. The results demonstrate the presence of sulfides—predominantly pyrite and chalcopyrite, with minor galena and Ti-oxide phases, as additional components of the pigment. ATR-FTIR analysis indicates the presence of C=O and C–H groups, consistent with an organic origin. Transmission electron microscopy images of pigment show variously deformed, originally spherical ～100?nm particles rich in sulfide and carbon, which are interpreted as thin coatings of pigment on now dissolved opaline silica spheres. Laser-ablation ICP-MS analysis identifies remnant silica in pigment concentrates, which may be interpreted as opaline silica surviving HF treatment protected as inclusions in sulfides. When examined within the context of petrographic observations from more than 1000 opal nodules (nobbies) at Lightning Ridge, these new results suggest that pigment carbon and sulfides in the nodules formed microbially under initially anoxic groundwater conditions, within pre-existing cavities concurrently being filled with silica sol ultimately derived from chemical weathering of feldspar-rich volcaniclastic sediment. Intensely black pigment layers observed at the floor of many nodules indicate settling of dark, high-density (sulfide–Ti-oxide-rich) pigment within cavities, with the implication that sulfate-reducing bacterial (SRB) activity commences early during the silica sol-gel ripening process. Microbial activity may persist until after the cavity has completely filled with the silica sol, as illustrated by abundant black opals with uniformly distributed pigment. Pigment formed at this stage may no longer be able to settle out within the ripening and increasingly viscous silica gel, thus forming pigmentation throughout the opal cavity. The existence of ‘amber’, pigment-poor opal with intensely black basal pigment layers is interpreted as signalling a lack of sulfate to sustain further SRB activity, or a change to more oxidising conditions, possibly related to interaction with surface waters within a downward-penetrating weathering front. A change in redox conditions would shut off activity of SRB and thus sulfide pigment production and allow development of aerobic microbial activity as described by others.  相似文献   

Investigation of Soil Shear-Strength Parameters and Prediction of the Collapse of Gully Walls in the Black Soil Region of Northeastern China   总被引：1，自引：0，他引：1  

《自然地理学》2013,34(2):161-178

The collapse of gully walls is an important mode of gully erosion, and it depends strongly on two soil shear-strength parameters: cohesion and the internal friction angle. However, little research has examined these parameters in China's black soil region. In the present study, we sampled six groups of surface soils from four different land uses, and two groups of soils at depths of 30 cm and 60 cm. The cohesion (c) and internal friction angle (φ) of each group were determined at 10 levels of water content. The results show that c increased with increasing water content until a certain level (12% for the surface soils, and 14% for the deeper soils), after which c decreased. Internal friction angle generally decreased with increasing water content. We developed a model predicting collapse of gully walls based on four parameters: dry bulk density, water content, crack depth, and the width of the soil collapse. The model predicts that soil collapse would occur at two levels of water content: dry and wet conditions. Field data showed that collapse only occurred under the wet condition; the critical mass water content given by the model is between 31.0% and 33.8% moisture.  相似文献   

Primordial black holes     

Maxim Yu. Khlopov 《天体物理学报》2010,(6):495-528

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