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Ionization state of cosmic hydrogen by early stars and quasars

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Research in Astronomy and Astrophysics 2009年第6期9卷 665-681页

作者： Xiao-Chun Mao1,2.1 National Astronomical Observatories, Chinese Academy of Sciences, beijing 100012. china 2.Graduate University of Chinese Academy of Sciences, beijing 100049, {2. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Cosmic hydrogen is reionized and maintained in its highly ionized state by the ultraviolet emission attributed to an early generation of stars and quasars. The Lyα opacity observed in absorption spectra of high-redshift quasars permits more stringent constraints on the ionization state of cosmic hydrogen. Based on density perturbation and structure formation theory, we develop an analytic model to trace the evolution of the ionization state in the post-overlap epoch of reionization, in which the bias factor is taken into account. For quasars, we represent an improved luminosity function by utilizing a hybrid approach for the halo formation rate that is in reasonable agreement with the published measurements at 2.≤ z ≤ 6. Comparison with the classic Press-Schechter mass function of dark matter halos, we demonstrate that the biased mass distribution indeed enhances star formation efficiency in the overdense environment by more than 2. per cent following the overlap of ionized bubbles. In addition, an alternative way is introduced to derive robust estimates of the mean free path for ionizing photons. In our model, star-forming galaxies are likely to dominate the ionizing background radiation beyond z = 3, and quasars contribute equally above a redshift of z ～ 2.5. From 5 ≤ z ≤ 6, the lack of evolution in photoionization rate can thus be explained by the relatively flat evolution in star formation efficiency, although the mean free path of ionizing photons increases rapidly. Moreover, in the redshift interval z ～ 2.- 6, the expected mean free path and Gunn-Peterson optical depth obviously evolve by a factor of ～ 500 and ～50 respectively. We find that the relative values of critical overdensities for hydrogen ionization and collapse could be 430% at z ≈2.and 2. at z ≈6, suggesting a rapid overlap process in the overdense regions around instant quasars following reionization. We further illustrate that the absolute estimates of the fraction of neutral hydrogen computed fr

关键词： cosmology theory -- formation galaxies -- quasars general -- diffuse radiation -- intergalactic medium

Multi-level decollement zones and detachment deformation of Longmenshan thrust belt,Sichuan Basin,southwest china

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Science china Earth Sciences 2008年第S2期51卷 32-43页

作者： TANG LiangJie1,2.3,YANG KeMing4,JIN WenZheng1,2.3,L ZhiZhou4 & YU YiXin1,2.3 1 State Key Laboratory of Petroleum Resource and Prospecting,china University of Petroleum,beijing 102.49,china 2.Key Laboratory for Hydrocarbon Accumulation Mechanism,china University of Petroleum,Ministry of Education,beijing 102.49,china 3 Basin and Reservoir Research Center,china University of Petroleum,beijing 102.49,china 4 Southwest Division Company,SINOPEC,Chengdu 610081,china 1. State Key Laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China 2. Key Laboratory for Hydrocarbon Accumulation Mechanism China University of Petroleum Ministry of Education Beijing 102249 China 3. Basin and Reservoir Research Center China University of Petroleum Beijing 102249 China 4. Southwest Division Company SINOPEC Chengdu 610081 China

As is well known that many decollement layers were developed in the Longmenshan thrust belt,Si-chuan Basin,china. Through field investigation,explanation of seismic profiles and analysis of the balanced sections,we can divide the decollement zones into 3 categories: (1) the deep level decolle-ment zones,including the crust-mantle decollement layer,intracrustal decollement layer,and presinian basal decollement layer. The main structural styles of their deformation are the crust-mantle decoup-ling detachment deformation,the basal ductile shear deformation,etc.; (2. the middle level decollement zones,including the Cambrian-Ordovician decollement layer,the Silurian decollement layer,etc.,the main structural styles of their deformation are the isopachous fold,the angular fold,the saddle struc-ture,and the combination styles of them; and (3) the shallow level decollement zones,including the Xujiahe Formation decollement layer of Upper Triassic and the Jurassic decollement layers,the main structural styles of their deformation are the thrust-nappe tectonic,the pop-up,the triangle zone ,the duplex,etc. Multi-level decollement zones not only made the Longmenshan thrust belt develop many different deformation styles from deep place to shallow place,but also made some local areas have the superimposition of the tectonic deformation apparently. This study indicates that the multi-level de-collement zones have a very important effect on the shaping and evolution of the Longmenshan thrust belt.

关键词： decollement layer structural styles multi-level decollement zones Longmenshan thrust belt

Ecological rebuilding and land reclamation in surface mines in Shanxi Province, china

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Journal of Environmental Sciences 2000年第4期12卷 486-497页

作者： MIAO Ze wei 1, BAI Zhong ke 2. GAO Lin 1 (1. Research Center for Eco Environmental Sciences, Chinese Academy of Sciences, beijing 100085, china E\|mail: miaozewei@*** 2. Department of Soil Science, Shanxi Agricultural University Taigu, 03 中科院生态环境研究中心北京 1 0 0 0 85 山西师范大学山西临汾 0 3 0 80 1

It is well known that the mining industry produces a large amount of derelict land, and causes pollution of water loss and soil erosion as well as other environmental damage in china. As land is under pressure in china, it is now policy to restore or reclaim land despoiled by mining, the aim being to develop sustainable and healthy arable land ecosystems. This paper outlines the principles and approaches of ecological restoration, which have been adopted in Shanxi Province with reference to three typical surface mines. In the research, the principles of ecological engineering and ecological succession are considered as the critical theories of ecological restoration in mine degraded land. Meanwhile, the paper made a comparative research on main links of ecological rebuilding in three surface mines in Shanxi Province, which include new land construction, treatment of toxic substances, control of soil erosion, fertility management, irrigation, ecological planning and the establishment of legislation systems. As the research demonstrated, for successful restoration, new land construction is the fundamental framework, but it must be integrated with ecological engineering including ecological planning, the control of soil erosion and vegetation establishment and ecosystem creation in order to optimise land productivity and soil fertility. In addition, the establishment of the legislation systems and organization of administration are also indispensable aspects of ecological rebuilding in mined land.

关键词： ecological restoration land reclamation open-pit mine

Features of inclusions in the Funiushan gold deposits of Central china and its implications for prospecting

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Chinese Science Bulletin 1999年第S2期44卷 15-16页

作者： ZHANG Zhengwei~1, ZHU Bingquan~1 and DENG Jun~2.1. Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, china 2. china University of Geoscience, {2. 100083, china Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China china University of Geoscience Beijing 100083 China

GOLD mineralization popularly occurs in Funiushan area. Based on the studies on more than 40 gold deposits or ore spots, it is shown that most of them are small in scale except the Pengou gold deposit, whichcan be developed into a medium one. The Pengou is a gold deposit of medium-low temperature hydrothermal type. 1 Geological setting The Funiushan gold mineralization zone lying in the contiguous region of Nanzhao, Fangcheng andLushan Counties, Henan Province, is stituated on the tectonic and geochemical boundary between theNorth china block and Qinling Orogenic belt, and transverses the two first-grade tectonic units. Thehost rocks are mainly the strata of Xionger group （Pt2./sub> ） and the Funiushan granitic batholith. The Penggougold deposit is just located on the large-scale fault of Xiatang-Guihe. A series of metamorphic rocks ofXionger Group outcroped in the north of the deposit. 2.The features of deposit The ore bodies mostly appear in thick plate with sag-and-swell variation. The gold-bearing alterationzone from upper to lower layers can be divided as granite→ pyritization and phyllic alteration→ alteredgranitic porphyry→quartz vein→pyritization and phyllic alteration→cataclastic granite with phyllic alteration, i. e. the upper and lower gold-bearing layers can be separated by the altered granite. The ore

关键词： gold deposit inclusion geochemistry Funiushan.

Infrared Galaxies in the Nearby Universe

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Chinese Journal of Astronomy and Astrophysics 2008年第6期8卷 643-652页

作者： Jian-Ling Wang 1 National Astronomical Observatories,Chinese Academy of Sciences,beijing 100012.{2. 2.Graduate School of Chinese Academy of Sciences,beijing 100049,{2. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate School of Chinese Academy of Sciences Beijing 100049 China

We used the Sloan Digital Sky Survey （SDSS） Data Release 5 （DR5） to study the morphological properties of 1137 nearby infrared （IR） galaxies, most of which are brighter than 15.9 mag in r-band. This sample was drawn from a cross-correlation of the Infra-Red Astronomical Satellite （IRAS） point source catalog redshift survey with DR5 at z ≤ 0.08. Based on this IR galaxy sample, we constructed five volume-limited sub-samples with IR luminosity ranging from 10^9.5 L⊙ to 10^12.⊙. By deriving the IR luminosity functions （LF） for different morphological types, we found that normal spiral galaxies are the dominant population below LIR ~ 8 ~ 10^10 L⊙; while the fraction of barred spiral galaxies increases with increasing IR luminosity and becomes dominant in spiral galaxies beyond LIR ≈ 5 × 10^10L⊙. As the IR luminosity decreases, the IR galaxies become more compact and have lower stellar masses. The analysis also shows that normal spiral galaxies give the dominant contribution to the total comoving IR energy density in the nearby universe, while, in contrast, the contribution from peculiar galaxies is only 39%.

关键词： galaxies evolution galaxies interactions galaxies starburst infrared galaxies galaxies luminosity function

Southeastern extension of the Red River fault zone (RRFZ) and its tectonic evolution significance in western South china Sea

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Science china Earth Sciences 2006年第8期49卷 839-850页

作者： LIU Baoming1,2.3, XIA Bin1, LI Xuxuan1,3, ZHANG Minqiang1,3, NIU Binhua2. ZHONG Lifeng1, JIN Qinghuan1,4 & JI Shaocheng1,5 1. Key Laboratory of Marginal Sea Geology and Resources, Chinese Academy of Sciences,Guangzhou 510640, china 2. china University of Geosciences ({2.), {2. 100083, china 3. Research Center of Science & Technology Department, CNOOC, {2. 10002., china 4. Guangzhou Marine Geological Survey, Ministry of Land & Resources, Guangzhou 510075, china 5. Ecole Polytechnique Montreal, H3C3A7, Canada 1. Key Laboratory of Marginal Sea Geology and Resources Chinese Academy of Sciences Guangzhou 510640 China 2. china University of Geosciences (beijing) Beijing 100083 China 3. Research Center of Science & Technology Department CNOOC Beijing 100027 China 4. Guangzhou Marine Geological Survey Ministry of Land & Resources Guangzhou 510075 China 5. Ecole Polytechnique Montreal H3C3A7 Canada

Recent geophysical surveys and basin modeling suggest that the No.1 fault in the Ying- gehai basin (YGHB) is the seaward elongation of the Red River fault zone (RRFZ) in the South china Sea (SCS). The RRFZ, which separates the South china and Indochina block, extends first along the Yuedong fault, offshore of Vietnam, and then continues southward and breaks off into two branches: the Lupar fault and the Tinjia fault. The southern extension of the Lupar fault dies out beneath the NW Borneo while the Tinjia fault extends southeast and reaches the Brunei-Sabah area. According to the gravity and geomagnetic data, and the tectonic evolution of the basins, there are different evolution histories between the Wan’an basin (WAB) and the basins in the Nansha block. The Tinjia fault may be the boundary between the Balingian block and the Nansha block. Hence, the line linking the Yue- dong fault and the Tinjia fault, which both are continental margin faults and strike-slip ones in the geological evolution histories, constitute the boundary between the Indochina and Nansha block. The Lupar fault, in contrast, is an intraplate fault within the Indochina block. The results provide new hints for reconstructing the tectonic evolution history of the RRFZ and the opening of the SCS, and also a framework for hydrocarbon prospecting in the region.

关键词： Red River fault zone, tectonic evolution, fault, extension, western South china Sea.

Analysis on the decadal scale variation of the dust storm in North china

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Science china Earth Sciences 2005年第12期48卷 2260-2266页

作者： KANG Dujuan1,2.& WANG Huijun1 1. NZC/LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100871, china 2. Environmental Fluid Mechanics Laboratory, Stanford University, Stanford CA 94305, USA 1. NZC/LASG Institute of Atmospheric Physics Chinese Academy of Sciences 100871 Beijing China 2. Environmental Fluid Mechanics Laboratory Stanford University 94305 Stanford CA USA

In this paper, the temporal variation characteristics of the dust storm in North china are investigated. Based on power spectrum analysis and wavelet analysis, 1956-1970 and 1985-1999 are chosen as the high-frequency and low-frequency dust storm decades respectively. Analysis results clearly show that the spring and wintertime anomalous atmospheric circulation between these two dec-ades are significantly different. Compared with the former decade, there are a strengthened polar vortex, enhanced westerlies near 50°N, and a weak East Asian major though in the winter of the latter decade. The north and center parts of the Siberian high and the Aleutian low become weak. The southerly and easterly wind anomalies appear over the north and east parts of china, which implies the weakening of East Asian winter monsoon. Meanwhile, northern china experiences warmer winters and wetter springs, which are in favor of the weakening of dust storm intensity in North china. There are significant out-of-phase relationships between dust frequency and wintertime westerly intensity, as well as between dust frequency and Arctic Oscillation. It is also found that the frequency of dust weather is strongly re-lated to winter-springtime East Asian monsoon intensity.

关键词： dust storm, climate anomaly, decadal scale variability, East Asian monsoon, AO.

Estimation of methane and nitrous oxide emissions from biomass waste in china:A case study in Hebei Province

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Science china(Technological Sciences) 2010年第1期53卷 19-23页

作者： LUO YuXiang1,WANG Wei1,WAN Xiao2.DENG Zhou2.& ZHU CuiPing2.1 Department of Environmental Science and Engineering,Tsinghua University,beijing 10084,china 2.J&K china Cleaning Energy Technology Company Limited,beijing 100085,china 1. Department of Environmental Science and Engineering Tsinghua University Beijing 10084 China2. J&K China Cleaning Energy Technology Company Limited Beijing 100085 China

Crop residue,animal manure and MSW are selected as representative biomass *** gas emissions from treatment and disposal process of biomass waste in Hebei province are estimated for the period from 2.02.to 2.07,using the methodologies recommended by the Intergovernmental Panel on Climate *** gas emission was about 10 Mt CO2.equivalent *** 6% of greenhouse gas emission came from open burning of crop residue,74% from management system of animal manure,and 2.% from MSW *** all the greenhouse gas sources,landfill is the most concentrated one,and has significant potential of emission reduction.

关键词： biomass waste methane nitrous oxide IPCC methodology

Analysis of the severe group dust storms in eastern part of Northwest china

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Journal of Geographical Sciences 2002年第3期12卷 357-362页

作者： ZHOU Zijiang, WANG Xiwen(1. National Meteorological Center, beijing 100081, china 2. Lanzhou Central MeteorologicalObservatory, Lanzhou 73002., china) National Meteorological Center 北京 100081 Lanzhou Central Meteorological Observatory Lanzhou 730020

Based on the available original dust storm records from 60 meteorological stations, we discussed the identification standard of severe dust storms at a single station and constructed a quite complete time series of severe group dust storms in the eastern part of Northwest china in 1954–2.01. The result shows that there were 99 severe group dust storms in this region in recent 48 years. The spatial distribution indicates that the Alax Plateau, most parts of the Ordos Plateau and most parts of the Hexi Corridor are the main areas influenced by severe group dust storms. In addition, the season and the month with the most frequent severe group dust storms are spring and April, accounting for 78.8% and 41.4% of the total events respectively. During the past 48 years the lowest rate of severe group dust storms occurred in the 1990s. Compared with the other 4 decades, on the average, the duration and the affected area of severe group dust storms are relatively short and small during the 1990s. In 2.00 and 2.01, there were separately 4 severe group dust storms as the higher value after 1983 in the eastern part of Northwest china.

关键词： eastern part of Northwest china severe group dust storms temporal and spatial distribution characteristics