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Science china Earth sciences 2005年第9期48卷 1501-1509页

作者： CHEN Junfeng1,2. LI Xiubin2.& ZHANG Ming2.1. institute of Remote Sensing & GIS, Peking University, Beijing 100871, china 2. institute of Geographical sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, china institute of Remote Sensing & GIS Peking University Beijing China institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing Chin

Impacts of land cover changes on watershed hydrology have been a long-term academic concern with acute dispute. But little attention has been paid to such effects on mesoscale river basins, where the society has a closer link to river hydrology. The present study focuses on a mesoscale river basin, the Suomo Basin that is located on the upper reaches of the Yangtze River. Land covers in the basin in the years 1970, 1986 and 1999 were mapped. A lumped hydrologic model, CHARM, and a distributed hydrologic model, SWAT, were used to model the impacts of both land-cover change and climate variation on river runoff during the past four decades. The results show that the contribution of climate variation to the change of runoff regime makes up 60%―80%, while that of land cover changes only 2.%.

关键词： climate variation, land-cover changes, Suomo Basin, CHARM model, SWAT model.

Physical mechanisms of plant roots affecting weathering and leaching of loess soil

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Science china Earth sciences 2006年第9期49卷 1002-1008页

作者： LI Yong1,2. ZHANG Qingwen1,2. WAN Guojiang3, HUANG Ronggui3, PIAO Hechun3, BAI Lingyu2.& LI Lu2.1. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, institute of Soil and Water Conservation, chinese academy of sciences, Yangling 712.00, {2. 2. institute of Agro-Environment and Sustainable Development, chinese academy of Agricultural sciences, Beijing 100081, {2. 3. institute of Geochemistry, chinese academy of sciences, Guiyang 550002. {2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Chinese Academy of Sciences Yangling China institute of Agro-Environment and Sustainable Development Chinese Academy of Agricultural Sciences Beijing China institute of Geochemistry Chinese Academy of Sciences Guiyang China

Plant roots have potential impacts on soil mineral weathering and *** objective is to understand the physical mechanisms of plant roots affecting weathering andleaching of loess soil. Root densities were measured through the method of a large-size dug profile,and transport fluxes of soil elements were determined using an undisturbed monolith soilinfiltration device on the hilly and gully regions of the chinese Loess Plateau. The results showthat the improvement effects of soil environment by plant roots are mainly controlled by the densityand weight of the fibrous roots with the diameters less than 1 mm. Plant roots have the strongereffects on soil physical properties than chemical properties. The principal components analysis(PCA) indicates that soil physical properties by plant roots account for 56.7% of variations in soilenvironment whereas soil chemical properties and pH contribute about 2..2. of the soil *** roles of plant roots in controlling soil weathering and leaching increased in the followingorder: infiltration enhancement > increase of bio-active substance > stabilization of soilstructure. The effects of plant roots on soil mineral weathering and leaching can be quantifiedusing the multiple regression models with the high prediction accuracies developed in this study.

关键词： plant roots, soil weathering and leaching rates, soil environment field, principal components analysis (PCA), chinese Loess Plateau.

Magnetron sputtering synthesis of large area well-ordered boron nanowire arrays

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Science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 403-415页

作者： CAO Limin1,2. ZHANG Ze2.& WANG Wenkui1,2.1. Key Laboratory of Metastable Materials Science and Technology and College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, china 2. institute of Physics, {2., Beijing 100080, china Key Laboratory of Metastable Materials Science and Technology and College of Materials Science and Engineering Yanshan University Qinhuangdao China institute of Physics Chinese Academy of Sciences Beijing China

One-dimensionally nanostructured materials, such as nanowires and nanotubes, are the smallest dimensional structures for efficient transport of electrons and excitons, and are therefore critical building blocks for nanoscale electronic and mechanical devices. In this paper, boron nanowires with uniform diameters from 2. to 80 nm were synthesized by radio-frequency magnetron sputtering of pure boron powder and B2.3 powder mixtures in argon atmosphere. The boron nanowires produced stand vertically on the substrate surface to form well-ordered arrays over large areas with self- organized arrangements without involvement of any template and patterned catalyst. The high-density boron nanowires are parallel to each other and well distributed, forming highly ordered and uniform arrays. A more interesting and unique feature of the boron nanowires is that most of their tips are flat rather than hemispherical in morphologies. Detailed studies on its structure and composition indicate that boron nanowires are amorphous. Boron nanowire appears as a new member in the family of one-dimensional nanostructures. Considering the unique properties of boron-rich solids and other nanostructures, it is reasonable to expect that the boron nanowires will display some exceptional and interesting properties. A vapor-cluster-solid (VCS) mechanism was proposed to explain the growth of boron nanowires based on our experimental observations.

关键词： boron nanowires, magnetron sputtering, arrays, self-assembly.

Experimental study of composite medium with simultaneously negative permeability and permittivity

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Science china(Physics,Mechanics & Astronomy) 2004年第1期47卷 64-78页

作者： SUI Qiang1, 2.& LI Fang1 1. institute of Electronics, chinese academy of sciences, Beijing {2., china 2. School of Information, Beijing Broadcasting institute, Beijing 10002., china Correspondence should be addressed to Sui Qiang (email: suiqiang@***) Received July 2., 2.03 institute of Electronics Chinese Academy of Sciences Beijing 100080 China School of Information Beijing Broadcasting Institute Beijing 100024 China

This paper focuses on a composite medium structure that exhibits simultan- eously negative values of effective permeability and permittivity, and our experimental study in an anechoic chamber. The experiment results show that the artificial medium, based on a periodic array of interspaced conducting nonmagnetic split ring resonators and continuous metallic wires, can have a simultaneously negative effective permeability and permittivity within a frequency region in the microwave regime under certain linearly polarized waves.

关键词： permittivity, permeability, negative index of refraction, split ring resonator, LHM, RHM.

Human remains and the environment of Early Pleistocene in the Nihewan Basin

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Science china Earth sciences 2004年第5期47卷 437-444页

作者： CAI Baoquan1 & LI Qiang2.1. Department of History, Xiamen University, Fujian 361005, china 2. institute of Vertebrate Palaeontology and Palaeoanthropology, {2., Beijing 100044, china Department of History Xiamen University Fujian 361005 China Inst. of Vertebrate Palaeontology Chinese Academy of Sciences Beijing 100044 China

A new Early Pleistocene Paleolithic site was found in July 2.01 in the Nihewan Ba-sin, Hebei Province. Totally 500 mammal specimens assigned to 2. species and 5 lithic artifacts were collected. The coexistence of Allophaiomys deucalion, Borsodia chinensis and Yangia tingi provides important evidence of chronology. On the basis of the comparison of mammalian fauna, the date of Paleolithic artifacts is probably earlier than 1.8 MaBP, possibly 2.0 MaBP. This is the earliest evidence of hominid activity found so far in North china. The hominid at that time in the Nihewan Basin lived in an environment of arid grasslands with scattered trees of temperate zone. This discovery is significant to the study of human origin and cultural development.

关键词： human remains, environment, Early Pleistocene, Nihewan.

General inverse of Stokes, Vening-Meinesz and Molodensky formulae

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Science china Earth sciences 2006年第5期49卷 499-504页

作者： CHENG Luying1,2.& XU Houze1 1. institute of Geodesy and Geophysics, chinese academy of sciences, Wuhan 430077, {2. 2. Xi’an Research institute of Surveying and Mapping, Xi’an 710054, {2. institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan China Xi’an Research institute of Surveying and Mapping Xi’an China

The operator operations between the disturbing potential and the geoidal undulation, the gravity anomaly, the deflection of the vertical are defined based on the relations among the gravity potential, the normal gravity potential and the disturbing potential. With the sphere as the boundary surface, based on the solution of the external boundary value problem for the disturbing potential by the spherical harmonics in the physical geodesy, the general inverse Stokes’ formula, the general inverse Vening-Meinesz formula and the general Molodensky’s formula are derived from the operator operations defined. The general formulae can get rid of the restriction of the classical formulae only used on the geoid. If the boundary surface is defined as the geoid, the general formulas are degen- erated into the classic ones.

关键词： spherical harmonics, boundary value problem, general inverse Stokes' formula, general inverse Vening-Meinesz formula, general Molodensky's formula.

Debris Flow Hazard Assessment Based on Support Vector Machine

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Wuhan University Journal of Natural sciences 2006年第4期11卷 897-900页

作者： YUAN Lifeng 1, 2., ZHANG Youshui 3 1. institute of Mountain Hazards and Environment, chinese academy of sciences, Chengdu 610041, Sichuan, {2. 2. Graduate University of chinese academy of sciences, Beijing 100049, {2. 3. institute of Geographical sciences and Natural Resources Research, chinese academy of sciences, Beijing 100101, {2. institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu Sichuan China Graduate University of chinese academy of sciences Beijing China institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Seven factors, including the maximum volume of once flow , occurrence frequency of debris flow , watershed area , main channel length , watershed relative height difference , valley incision density and the length ratio of sediment supplement are chosen as evaluation factors of debris flow hazard degree. Using support vector machine （SVM） theory, we selected 2.9 basic data of 37 debris flow channels in Yunnan Province as learning samples in this study. We create a debris flow hazard assessment model based on SVM. The model was validated though instance applications and showed encouraging results.

关键词： debris flow hazard assessment support vector machine (SVM)

The features of gravity field and deep structure in western part of the South Yellow Sea

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chinese Science Bulletin 2000年第8期45卷 759-764页

作者： WANG Qianshen1 & AN Yulin1. institute of Geophysics, chinese academy of sciences, Beijing 100101, {2. 2. chinese University of Geology, Beijing 100083, {2. institute of Geophysics Chinesc Academy of Sciences Beijing China chinese University of Geology Beijing China

The gravity data from the sea region to the west of 12.° E of the South Yellow Sea have been processed and the feature of gravity fields analyzed. An experience relationship formula on the filter wavelength and corresponding depth has been put forward. Combined with the geological and seismic data, the deep tectonic framework and structural characters as well as possible favourable prospecting district for hydrocarbon in the South Yellow Sea have been discussed and analyzed.

关键词： western part of the South Yellow Sea gravity field deep structure.

The proof of FFD(L)≤11/9OPT(L) +7/9

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chinese Science Bulletin 1997年第15期42卷 1262-1265页

作者： LI Rongheng, YUE Minyi1. Department of Mathematics, Hunan Normal University, Changsha 410081, china 2. institute of Applied Mathematics, {2., Beijing 100080, china Department of Mathematics Hunan Normal University Changsha 410081 China institute of Applied Mathematics Chinese Academy of Sciences Beijing 100080 China

THE one-dimensional bin-packing problem is defined as follows: for a given list L={p1, p2.…, Pn}, where 0i≤1 denotes the item and its size as well, we are to pack all the items in-to bins, each of which has a capaci... 详细信息

THE one-dimensional bin-packing problem is defined as follows: for a given list L={p1, p2./sub>,…, Pn}, where 0i≤1 denotes the item and its size as well, we are to pack all the items in-to bins, each of which has a capacity 1, and the goal is to minimize the number of bins *** first-fit-decreasing （FFD） algorithm is a famous approximate algorithm for the bin-pack-ing problem. The FFD algorithm first sorts all the list into non-increasing order and then pro-cesses the pieces in that order by placing each item into the first bin into which it fits.

关键词： bin-packing minimal counter-example weigtht-function FFD-algorithm.

Geochemical simulation of the formation of brine and salt minerals based on Pitzer model in Caka Salt Lake

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Science china Earth sciences 2004年第8期47卷 720-726页

作者： LIU Xingqi1, CAI Keqin2.& YU Shengsong3 1. Nanjing institute of Geography and Limnology, chinese academy of sciences, Nanjing 2.0008, {2. 2. {2. University of Geosciences, Beijing 100083, {2. 3. institute of Salt Lakes, chinese academy of sciences, Xining 810008, {2. Nanjing institute of Geography and Limnology Chinese Academy of Sciences Nanjing China china University of Geosciences Beijing China institute of Salt Lakes Chinese Academy of Sciences Xining China

The geochemical simulation of the formation of brine and salt minerals based on Pitzer model was made in Caka Salt Lake. The evolution of the mixed surface-water and the mineral sequences were calculated and compared with the hydrochemical compositions of the brine and the salt minerals of the deposit in Caka Salt Lake. The results show that the formation temperature of the lake is between 0°C and 5°C, which is well identical with other studies. The mixing of salt-karst water with the surface waters, neglected by the former researchers, is very important to the formation of the lake, indicating that the initial waters resulting in the formation of the lake are multi-source. It is the first time to use Pitzer model in china for making geochemical simulation of the formation and evolution of inland salt lake and satisfactory results have been achieved.

关键词： Pitzer model,Caka Salt Lake,geochemical simulation,salt-karst water.