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Pathways of birnessite formation in alkali medium

Science china Earth Sciences 2005年第9期48卷 1438-1451页

作者： FENG Xionghan1, TAN Wenfeng1, LIU Fan1, HUANG Qiaoyun1 & LIU Xiangwen2 1. College of Resources and environment, Huazhong Agricultural University, wuhan 43.070, china 2. Testing Center, china University of Geosciences, wuhan 43.074, china College of Resources and environment Huazhong Agricultural University Wuhan China Testing Center China University of Geosciences Wuhan China

Birnessite is a common weathering and oxidation product of manganese-bearing rocks. An O2 oxidation procedure of Mn(OH)2 in the alkali medium has been used to synthesize birnessite. Fast and powder X-ray diffraction (XRD), transmission electron microscopy (TEM), electron diffraction (ED), energy dispersed X-ray analysis (EDAX), infrared spectroscopy (IR) techniques and chemical composition analysis, Eh-pH equilibrium diagram approaches were employed to investigate the reaction process and pathways of birnessite formation. Results showed that the process of the birnessite formation could be divided into four stages: (1) forma- tion stage for hausmannite and feitknechtite, (2) stage of transformation of hausmannite and feitknechtite to buserite, (3. buserite crystal growing stage, and (4) stage of conversion of buser- ite into birnessite. Mn(OH)2 was mainly present as amorphous state only for a short initial time of oxidation reaction. In the oxidation process, buserite formed following two pathways by recrys- tallization after dissolution of the intermediates, and the transformations of the minerals de- pended on the Eh determined by the dissolved O2 concentration on their surfaces. The results are fundamental in further exploration on the mechanism of birnessite formation in the alkali medium. A great practical significance would also be expected with respect to the areas of mate- rial sciences.

关键词： birnessite, pathway of formation, reaction process, Eh-pH diagram, hausmannite, feitknechtite.

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Quenched moderate deviations principle for random walk in random environment

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Science china Mathematics 2010年第8期53卷 1947-1956页

作者： HONG WenMing 1 & WANG HuaMing 1,2 1 Key laboratory of Mathematics and Complex Systems of ministry of education & School of Mathematical Sciences,Beijing Normal University,Beijing 100875,{3. 2 Department of Basic Courses,Business College,Beijing Union University,Beijing 100025,{3. Key laboratory of Mathematics and Complex Systems of ministry of education & School of Mathematical Sciences Beijing Normal University Beijing China Department of Basic Courses Business College Beijing Union University Beijing China

We derive a quenched moderate deviations principle for the one-dimensional nearest random walk in random environment,where the environment is assumed to be stationary and *** approach is based on hitting time decompos... 详细信息

关键词： random walk in random environment moderate deviations principle hitting time

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A community-centric approach to automated service composition

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Science china(Information Sciences) 2010年第1期53卷 50-63页

作者： LIU XuanZhe1,2, HUANG Gang1,2 & MEI Hong1,2 1School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, china 2Key laboratory of High Confidence Software Technologies, ministry of {3., Peking University, Beijing 100871, china School of Electronics Engineering and Computer Science Peking University Beijing China Key laboratory of High Confidence Software Technologies Ministry of Education Peking University Beijing China

In the recent years, the web has kept growing rapidly and undergone tremendous changes towards a user-centric environment. With the proliferation of services available on the Internet, millions of users are able to voluntarily participate in and collaborate for their own interests and benefits by means of service composition. However, due to the ever increasing number of services, it then becomes a challenging issue to enable the users to rapidly select and compose the proper services. In this paper, we propose an approach which utilizes service communities for automated service composition. This paper makes three contributions. Firstly, we propose the service community architecture and identify two key components to facilitate service discovery and composition. Secondly, assisted by the service community, we provide two composition types to help users explore the space of potential composition opportunities without having to understand too many details of individual candidate services. Finally, we evaluate our approach by performance analysis and provide a web-based prototype that lowers the entry barrier for the users.

关键词： services computing service composition service community

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AN APPROACH TO SEPARATING THE CURRENT VELOCITY IN ESTUARINE AND COASTAL WATERS

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Journal of Hydrodynamics 2009年第4期21卷 512-519页

作者： NI Zhi-hui SONG Zhi-yao WU Li-chun State Key laboratory of Hydrology-Water Resources and Hydraulic Engineering Ocean College Hohai University Nanj ing 210098 China Key laboratory of Virtual Geographic environment Ministry of Education Nanjing Normal University Nanjing 210097 China Chongqing education College Chongqing 400067 China

In the near-shore waters, the actual flow is mainly induced by tide, wind and salinity, and the river water runoff should also be included as a component in the estuary waters. The interactions among these major components are very complicated. Many approaches were proposed to study isolated tide and wind-driven currents or run-off based on the measured velocity, with all its components taken as a whole. In this article, firstly, based on the actual hydrodynamic characteristics of estuarine and coastal waters, an approach is proposed to separate the measured velocity by considering the theoretical current velocity profiles and using the least squares method. The vertical structures of tidal, wind-driven currents, density current and runoff can be obtained as well as their proportions in the measured velocity. Then, this approach is applied to the analysis of velocity data obtained in the North Branch of Yangtze River estuary and of laboratory test data. The results are found to be satisfactory. Finally, this approach is used to separate the measured velocity in the South Branch of Yangtze River estuary, to determine not only the bed friction velocity and roughness height, but also the surface wind stress, and to estimate the wind velocity data above the water surface. The results show that this method is simple in principle, practical in use, and reasonable in obtained results. So it can be used to effectively analyze the field data.

关键词： tide wind-driven current density current river water runoff friction velocity roughness height velocity separation

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加强科学素养考查提高人才选拔质量——2024年高考理科综合全国卷试题评析

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中国考试 2024年第7期 91-96页

作者： National education Examinations Authority 教育部教育考试院

2024年高考理科综合全国卷试题落实立德树人根本任务,展现我国传统文化成果和科技成就,激发学生强国之志,发挥高考育人功能。试题加强考查科学素养,注重引导学生进行科学研究和实验探究,鼓励其运用所学知识解决生产生活中的实际问题,培... 详细信息

2024年高考理科综合全国卷试题落实立德树人根本任务,展现我国传统文化成果和科技成就,激发学生强国之志,发挥高考育人功能。试题加强考查科学素养,注重引导学生进行科学研究和实验探究,鼓励其运用所学知识解决生产生活中的实际问题,培养创新思维,激发学生崇尚科学、探索未知的兴趣。试题命制遵循高中课程标准,强化对学科必备知识的考查,引导教学回归基础,回归课堂,提质增效。

关键词：高考高考理科综合科学素养教考衔接

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Influence of the density and thickness variation of the lithosphere on the parameters of NNR-NUVEL plate model:a preliminary study

Influence of the density and thickness variation of the lith...

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中国地球物理学会第二十七届年会

作者： WenBin Shen~(1,2*) Rong Sun~1 1.Dept.of Geophysics,School of geodesy and Geomatics,wuhan University,wuhan {3.,china 2.Key Lab.of geospace environment and geodesy,wuhan University,wuhan {3.,china

＜正＞*** Plate models given by geological studies describe the relative motion of one plate with respect to other ***,there are many plate models available,like NUVEL,PB2002 and ***,a plate model may be described by its geometric figure and rotation *** describe the relative motion of the plates to the underneath asthenosphere,additional requirements are *** frequently used is the no net rotation （NNR） requirement which assumes that the net angular momentum of the lithosphere is *** this frame,the inertia moments of each plate is obtained by calculating the surface integration on the surface of a unit sphere since the density and thickness of the lithosphere is considered to be invariant with respect to ***

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Miocene Bahean stratigraphy in the Longzhong Basin, northern central china and its implications in environmental change

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Science china Earth Sciences 2006年第12期49卷 1270-1279页

作者： LI Jijun1,2, ZHANG Jun1, SONG Chunhui1, ZHAO Zhijun2, ZHANG Yong1, WANG Xiuxi 1, ZHANG Jianming1 & CUI Qiaoyu1 1. Key laboratory of Western china’s environmental Systems ({3. of education) & College of Earth and environment Sciences, Lanzhou University, Lanzhou 73.000, china 2. Jiangsu Key laboratory of environmental Change and Ecological Construction & College of Geography, Nanjing Normal University, Nanjing 210097, china Key laboratory of Western china’s environmental Systems ({3. of education) & College of Earth and environment Sciences Lanzhou University Lanzhou China Jiangsu Key laboratory of environmental Change and Ecological Construction & College of Geography Nanjing Normal University Nanjing China

Fossil mammal-riched Neogene strata are widely distributed in the southeast corner of the huge Longzhong Basin at Tianshui, Gansu Province, northern central china. Hipparion weihoense, a typical member of late Middle Miocene Bahean stage, was recently excavated at Yaodian along a well-exposed outcrop. Owing to the importance of the Bahean stage in the mammalian evolution and its potential for environmental change, we suggested a name of Yaodian Formation for the stratigra- phy, which is correlated to the Bahe Formation at Lantian, Shaanxi. High resolution paleomagnetic dating of the section shows that the Yaodian Formation covers the period between 11.67 Ma and 7.43.Ma, with the site bearing Hipparion weihoense being estimated at about 10.54―10.3. Ma, providing first magnetostratigraphic chronology for the Bahean Stage. The Yaodian Formation consists of fluvial channel deposits (11.67―10.40 Ma) at the bottom, floodplain deposits in the middle (10.40―9.23.Ma) and shallow lake sediments at the top (9.23.7.43.Ma). This upward fining sequence suggests that the relief in nearby mountain ranges such as West Qinling to the south and Huajia Ling to the north was greatly reduced after long-term denudation, fluvial transport capacity was low, and finally the drainage system was disintegrated, replaced with broad-shallow lakes in which only fine sediments like mud and marlite were deposited, indicating an old stage of development of a planation surface. A remarkable shift in ecology and climatic environment was found at 7.4―7.7 Ma when paleoclimate changed from early warm humid to late dry as indicated by sedimentary facies changed from early shallow lake sequence to late eolian red clays and a former coniferous-deciduous mixed forest was replaced by grassland, leading to great growth of Hipparion Fauna of Baodean stage in the region. Therefore, it is estimated that the present high relief of Qinling and drainage pattern did not come into being until Late Pliocene in response

关键词： Bahean stage,magnetostratigraphy,Yaodian Formation,Neogene,Longzhong Basin.

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Robust multiuser MIMO scheduling algorithms with imperfect CSI

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Science china(Information Sciences) 2012年第4期55卷 815-826页

作者： MAO JunLing 1,3.GAO JinChun 1,3.LIU YuanAn 1,3.XIE Gang 2,3.& ZHANG Jian 1,3.1 School of Electronic Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,china 2 School of Information and Communication Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,china 3.Key Lab of Universal Wireless Communications,ministry of {3.,Beijing University of Posts and Telecommunications,Beijing 100876,china School of Electronic Engineering Beijing University of Posts and Telecommunications Beijing China Key Lab of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications Beijing China School of Information and Communication Engineering Beijing University of Posts and Telecommunications Beijing China

Robust multiuser multiple-input-multiple-output (MIMO) scheduling algorithms are proposed in this *** imperfect channel state information (CSI),traditional scheduling algorithms for the multiuser MIMO system based on the zero forcing precoding scheme will lose some performance due to the multi-user interference (MUI).In order to improve the system average throughput,we study the robust multiuser MIMO scheduling problem with imperfect *** the average capacity formula,we derive a robust factor which can transform the robust multiuser MIMO scheduling problem into the traditional one,thus most existing non-robust scheduling algorithms can be robust if this factor is *** results show that compared with the traditional algorithms,the proposed robust algorithms can improve the system average throughput significantly under the CSI error environment.

关键词： multiuser MIMO (MU-MIMO) scheduling robust imperfect CSI

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A new grid-associated algorithm in the distributed hydrological model simulations

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Science china(Technological Sciences) 2010年第1期53卷 235-241页

作者： XU Rui1,2,HUANG XiaoXue1,LUO Lin1 & LI ShaoCai3.1 State Key laboratory of Hydraulics and Mountain River Engineering College of Architecture and environment,Sichuan University,Chengdu 610065,china 2 College of Electronic Engineering,Guilin University of Electronic Technology,Guilin 541004,china 3.College of Life Sciences,Sichuan University,Chengdu 610065,china State Key laboratory of Hydraulics and Mountain River Engineering College of Architecture and environment Sichuan University Chengdu China College of Electronic Engineering Guilin University of Electronic Technology Guilin China College of Life Sciences Sichuan University Chengdu China

This paper presents a new grid-associated algorithm to improve the performance of a D8 algorithm based distributed hydrological model *** algorithm is based on the well known single-flow D8 algorithm of grid *** algorithm allocates calculation priorities according to the distance between the units and the outlet,then carries out the ergodic computations of the hydrological units according to the priority *** the parallelized algorithm,a standard thread-level shared memory system for parallel programming(OpenMP-Open specifications for Multi Processing) was introduced,and the parallel coding was implemented in C lan-guage.A case study showed that the absolute speed-up ratio of the grid-associated algorithm is 1.64 over the original D8 algorithm,and the linear speed-up ratio of the parallel associated algorithm is 2.42 under 4 *** parallel grid-associated algorithm can be applied to a variety of research fields that use the grid method.

关键词： distributed hydrological model grid-association algorithm OpenMP parallel computing

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The vertical attenuation of irradiance as a function of turbidity: a case of the Huanghai (Yellow) Sea in spring

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Acta Oceanologica Sinica 2009年第5期28卷 66-75页

作者： LIN Shaoying ZOU Tao GAO Huiwang GUO Xinyu Key laboratory of Marine environment and Ecology Ministry of Education of China Ocean University of China Qingdao 266100 China Center for Marine environmental Studies Ehime University 2-5 Bunkyo-Cho Matsuyama 790-8577 Japan

The planar photosynthetically available radiation （PAR）, turbidity and concentration of chlorophyll a （chl a）, were measured at 26 stations in the Huanghai （Yellow） Sea during a cruise of china SOLAS from 19 to 27 March 2005. Due to low chl a （〈0.3. mg · m^-3.） in upper layers （above 5 m）, suspended particulate matter became the major factor that influenced the turbidity in early spring. The calculated vertical diffuse attenuation coefficient of PAR, K PAR , varied with water depths with a maximum value in the upper 5 m layer. The mean K PAR in survey area was 0.277 ± 0.07 m^-1 that is considerably higher than most of the other case 2 waters. Within the survey area, K PAR also showed distinct regional characteristics, corresponding to the distribution of turbidity. Based on measurements, the relationship between K PAR and turbidity as well as chl a was established. It was suggested that suspended particulate matter plays an important role in light attenuation in the Huanghai （Yellow） Sea in spring.

关键词： Photosynthetically available radiation Diffuse attenuation coefficient Turbidity Chlorophyll a the Huanghai (Yellow) Sea

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