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Ionization state of cosmic hydrogen by early stars and quasars

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, china 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 25 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

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A measuring method of effects of herbs based on classification used for intelligent calculation of efficacies of prescriptions

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Science china(Information Sciences) 2010年第10期53卷 2047-2061页

作者： GAO QuanQuan 1 & REN TingGe 2 1 academy of Math & Systems, chinese academy of Sciences, beijing 100190, china 2 beijing University of chinese Medicine, beijing 100029, china academy of Math & Systems Chinese Academy of Sciences Beijing China beijing University of chinese Medicine Beijing China

It is important to translate dosage of each medical herb in a prescription into intensity of its effects measured by mathematical models. In this paper, we present intelligent calculational algorithms on efficacies of prescriptions of chinese Medicine (CM), study "how curative effects of any herb depend on dosage" when constructing CM intelligent systems, and discuss relevant issues and definitions. In order to measure intensities of effects of all herbs reasonably, the natural classification method is proposed to classify herbs into 38 natural classes according to their dosage ranges using the knowledge of CM dosage and distribution rules of herbs. Then the 38 natural classes are clustered to 6 basic classes reflecting characteristic attributes of various herbs. Based on the results of classified herbs, a set of nonlinear measuring functions of intensities of effects is designed for various basic classes. These functions have been embedded in our intelligent calculation system of efficacies of prescriptions. The effects of 560 herbs and curative efficacies of more than 1000 prescriptions derived from "ShangHan Lun", "JinGui YaoLue", "Ming Jia Yi An", etc., have been calculated and discovered successfully. It is proved that the accuracy of theses results by these models has been obviously enhanced.

关键词： intelligent calculation mathematical modeling measuring method efficacies of prescriptions

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Combined adjustment project of national astronomical geodetic networks and 2000' national GPS control network

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Progress in Natural Science:Materials International 2005年第5期15卷 435-441页

作者： YANG Yuanxi1*, ZHA Ming2, SONG Lijie3, WEI Ziqing1, WANG Zhouping2, OUYANG Guichong2, XU Bilin2, WU Xiaoping3 and WANG Junqin4(1. Xi'an Research Institute of surveying and mapping, Xi'an 710054, china 2. Xi'an Informational and Technical Center of surveying and mapping, Xi'an 710054, china 3. Zhengzhou Institute of surveying and mapping, Zhengzhou 450052, china 4. The First surveying Team of Tianjin, Tianjin 300140, china) Xi'an Res. Inst. of surveying and mapping Xi'an 710054 China Xi'an Info. and Technical Ctr. of surveying and mapping Xi'an 710054 China Zhengzhou Inst. of surveying and mapping Zhengzhou 450052 China First surveying Team of Tianjin Tianjin 300140 China

The combined adjustment project of the nationwide astronomical geodetic networks and 2000' national GPS control network involve 48519 terrestrial observational stations and 2666 GPS observational stations. In the terrestrial network, 25107 stations are height fixed and 23412 stations are in three dimensions. 440793 terrestrial observations and 183668 unknowns are involved in the adjustment. The three-dimensional observational models for the adjustment have been established. The crustal deformation influences and corrections are researched. Fast methods of solving partitioned adjustment for super large-scale geodetic network have been studied. The standard deviations of three-dimensional coordinates for all stations are evaluated. As a result of the combined adjustment, a unified national geodetic network with nearly 50000 stations is established, the high accurate three-dimensional geocentric coordinates are obtained. The standard deviation for geoid is averagely 0.2 m, for vertical deflection is about 1.5″, for the horizontal position is about 0.12 m, for the geodetic height is about 0.14 m, and for the three-dimensional position is averagely 0.3 m.

关键词： astronomical geodetic network GPS network combined adjustment datum geocentric coordinates.

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Mineralization episode of porphyry copper deposits in the Jinshajiang-Red River mineralization belt: Re-Os dating

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Science china Earth Sciences 2005年第2期48卷 192-198页

作者： WANG Denghong, QU Wenjun, LI Zhiwei, YIN Hanlong4 & CHEN Yuchuan Institute of Mineral Resources, chinese academy of Geological Sciences, beijing 100037, china National Center of Rock and Mineral Analysis, chinese academy of Geological Sciences, beijing 100037, china Resource Assessment Center of Yunnan, Kunming 650011, china Institute of Geology and Geophysics, chinese academy of Sciences, beijing 100101, china chinese academy of Geological Sciences, beijing 100037, china Institute of Mineral Resources Chinese Academy of Geological Sciences Beijing China National Center of Rock and Mineral Analysis Chinese Academy of Geological Sciences Beijing China Resource Assessment Center of Yunnan Kunming China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing China chinese academy of Geological Sciences Beijing China

Re-Os isotopic dating for the molybdenites from the porphyry copper deposits of the Jinshajiang-Red River mineralization belt in Yunnan Province yields isochron ages of 33.9±1.1 Ma for the Machangqing deposit and 34.4±0.5 Ma for the Tongchang deposit. This result shows that both the Machangqing and the Tongchang porphyry Cu-Mo deposits from two different ore-fields formed simultaneously. This new data and the published Re-Os model ages of molybdenite (35.4 Ma, 35.9 Ma, 36.2 Ma) of the Yulong porphyry copper deposit in Tibet, which is located in the same Jinshajiang-Red River mineralization belt as the Machangqing deposit and the Tongchang deposit, suggest that these three Cenozoic porphyry copper deposits in the Jinshajiang-Red River mineralization belt were contemporary for their mineralization episode. That is to say, even their present locality is far away and nearly iso-distantly distributed, these three porphyry Cu(Mo) deposits belong to the same mineralization episode at the end of Eocene.

关键词： Re-Os isotopic dating, porphyry Cu deposits, Cenozoic, mineralization episode.

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Study on the generator f of the operators I_n and I_t

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Science china Mathematics 2010年第10期53卷 2589-2603页

作者： CHEN HanLin academy of Mathematics and Systems Science,chinese academy of Sciences,beijing 100190,china academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China

Define two operators In and It,the inner product operator In(g)(x) := j∈Zs(g,f(·-j))f(x-j) and the interpolation operator It(g)(x) := j∈Zs g(j)f(x-j),where f belongs to some space and integer s *** call f the generator of the operators In and *** is well known that there are many results on operators In and *** there remain some important problems to be further *** application we first need to find the available generators (that can recover polynomials as It(p) = p or In(p) = p,p ∈Πm-1) for constructing the relative *** this paper,we focus on the available generator in the class of spline *** shall see that not all spline functions can be used to construct available ***,we do find a spline function in S,of degree m-1,where m is even and S is a class of *** for odd m the problem is still *** on spline functions in this paper are new.

关键词： generator available generator inner product operator spline interpolation operator two-closed refinable

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Expert Consensus on the Prevention and Treatment of Chronic Hepatitis B in Children

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Infectious Diseases & Immunity 2024年第3期4卷 106-120页

作者： chinese Society of Infectious Diseases chinese Medical Association chinese Society of Hepatology chinese Medical Association Group of Infectious Diseases chinese Pediatric Society chinese Medical Association National Clinical Research Center for Infectious Diseases(beijing) Fu-Sheng Wang Shishu Zhu Min Zhang Jianshe Wang Shuangjie Li Junliang Fu Yuanyuan Li Yuming Guo Jing Li Hongmei Xu Wenxian Ouyang Yuemin Nan Sainan Shu Shuangsuo Dang Xiaoyuan Xu Taisheng Li Jinlin Hou 不详 The Fifth Medical Center of PLA General Hospital Beijing 100039China Fudan University Children’s Hospital Hunan Children’s Hospital Children’s Hospital of Chongqing Medical University Third Hospital Hebei Medical University Tongji Hospital Tongji Medical CollegeHuazhong University of Science and Technology The Second Affiliated Hospital of Xi’an Jiaotong University Peking University First Hospital Peking Union Medical College Hospital Chinese Academy of Medical Sciences&Peking Union Medical College Nanfang Hospital Southern Medical University

The aim of this consensus is to standardize the prevention, diagnosis, and treatment of chronic hepatitis B in children and to achieve the goal of “eliminating viral hepatitis as a major public health threat by 2030” issued by the World Health Organization. Formulated by organized experts of the chinese Society of Infectious Diseases and chinese Society of Hepatology, chinese Medical Association;Group of Infectious Diseases, chinese Pediatric Society, chinese Medical Association;and the National Clinical Research Center for Infectious Diseases (beijing), the consensus provides the latest evidence and recommendations for the prevention, diagnosis, and treatment of chronic hepatitis B in children.

关键词： Chronic hepatitis B Children Treatment Prevention Consensus

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Reconstruction of temperature series in china for the last 5000 years

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Progress in Natural Science:Materials International 2006年第8期16卷 838-845页

作者： GE Quansheng, WANG Shunbing and ZHENG Jingyun (Institute of Geographical Sciences and Natural Resources Research, chinese academy of Sciences, beijing 100101, china Graduate School of the chinese academy of Sciences, beijing 100039, china) Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Graduate School of the chinese academy of Sciences Beijing 100039 China

A temperature series with a 100 year resolution for the last 5000 years in china has been reconstructed by using 31 longterm temperature proxy series selected from recent publications in the last 20 years. The proxy records include pollens, stalagmites, lake-sediments, peat, ice cores and historical documents. The result reveals that in the millennial scale temperature variation it was warm in 3050-250 BC and it was cold in 250 BC-1950 AD. In the above two periods there were many stages of sub-scale temperature fluctuations. The result also shows an obvious temperature discrepancy on the century to multi-century scale between the Eastern Monsoon Region, the Qinghai-Tibet Region and the Northwestern Region in 2850 BC, 2350 BC, 1350 BC, 950-350 BC, 50-250 AD, and 550 AD. A comparison between the reconstructed series of this paper and some North Hemisphere temperature series indicates that in the longterm scale change, the temperature change in china is in phrase with that of the Northern Hemisphere during the last 5000 years, while on the century to multi-century scale there are differences at the beginning and end times, which may imply that temperature change does not occur simultaneously in different regions.

关键词： temperature series the last 5000 years china.

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Patterns of platinum-group elements in mantle peridotite, granulite xenoliths and basalt in Hannuoba

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chinese Science Bulletin 1999年第18期44卷 1676-1681页

作者： CHU Xuelei, LI Xiaolin, XU Jiuhua and LIU Jianming1. The Research Center of Mineral Resources Exploration , chinese academy of Sciences , beijing 100101, china 2. Institute of Geology , chinese academy of Sciences , beijing 100029, china 3. Institute of High Energy Physics , chinese academy of Sciences , beijing 100817 , china 4. beijing University of Science and Engineering , beijing 100083, china Corresponding author The Research Center of Mineral Resources Exploration Chinese Academy of Sciences Beijing China Institute of Geology Chinese Academy of Sciences Beijing China Institute of High Energy Physics Chinese Academy of Sciences Beijing China beijing University of Science and Engineering Beijing China

Neutron activation analysis after preconcentration of nickel sulfide fire assay was used in measurement of Ru, Ph, Pd, Os, Ir, Pt (i.e. PGE elements) and Au concentrations for basalt, mantle and granulite xenoliths in Hannuoba. The chondrite- and primitive mantle-normalized PGE patterns generally exhibit flat (for Iherzolite), negative slope (for harzburgite),

关键词： mantle xenolith granulite xenolith basalt platinum-group element Hannuoba.

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The principle of relativity, kinematics and algebraic relations

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 591-597页

作者： GUO HanYing1, HUANG ChaoGuang2,3, WU HongTu4 & ZHOU Bin5 1Institute of Theoretical Physics, chinese academy of Sciences, beijing 100190, china 2Institute of High Energy Physics, chinese academy of Sciences, beijing 100049, china 3Theoretical Physics Center for Science Facilities, chinese academy of Sciences, beijing 100049, china 4Department of Mathematics, Capital Normal University, beijing 100048, china 5Department of Physics, beijing Normal University, beijing 100875, china Institute of Theoretical Physics Chinese Academy of Sciences Beijing China Institute of High Energy Physics Chinese Academy of Sciences Beijing China Theoretical Physics Center for Science Facilities Chinese Academy of Sciences Beijing China Department of Mathematics Capital Normal University Beijing China Department of Physics Beijing Normal University Beijing China

Based on the relativistic principle and the postulate of universal invariant constants (c, l), all kinematic symmetries can be set up as the subsets of the Umov-Weyl-Fock-Hua transformations for the inertial motions. ... 详细信息

关键词： principle of relativity with (c l) Umov-Weyl-Fock-Hua transformations kinematics special relativity triple

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Regional soil moisture simulation for Shaanxi Province using SWAT model validation and trend analysis

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Science china Earth Sciences 2010年第4期53卷 575-590页

作者： LI MingXing1,2,MA ZhuGuo1 & DU JiWen3 1 Key Laboratory of Regional Climate-Environment Research for Temperate East Asia,Institute of Atmospheric Physics,chinese academy of Sciences,beijing 100029,china 2 Graduate University of chinese academy of Sciences,beijing 100049,china 3 Shaanxi Administration of Meteorology,Xi’an 710014,china Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of Sciences Beijing China Shaanxi Administration of Meteorology Xi’an China

The soil moisture in Shaanxi Province,a region with complex topography,is simulated using the distributed hydrological model Soil Water Assessment Tool(SWAT).Comparison and contrast of modeled and observed soil moisture show that the SWAT model can reasonably simulate the long-term trend in soil moisture and the spatiotemporal variability of soil moisture in the *** to NCEP/NCAR and ERA40 reanalysis of soil moisture show that the trend of variability in soil moisture simulated by SWAT is more consistent with the *** model results suggested that high soil moisture in surface soil layers appears in the southern Shaanxi with high vegetation cover,and the Qinling mountainous region with frequent orographic *** deeper soil layers,high soil moisture appears in the river basins and *** regional soil moisture showed a generally decreasing trend on all soil layers from 1951 to 2004,with a stronger and significant decreasing trend in deeper soil layers,especially in the northern parts of the province.

关键词： SWAT soil moisture content simulation validation trend analysis

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