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Terrestrial transect study on driving mechanism of vegetation changes

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Science china Earth sciences 2008年第7期51卷 984-991页

作者： ZHANG YuJin1,2 & ZHOU GuangSheng1 1 State key laboratory of Vegetation and Environmental Change, Institute of Botany, chinese academy of sciences, beijing 100093, china 2 Graduate University of chinese academy of sciences, beijing 100049, china 1. State key laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing 100093 China 2. Graduate University of chinese academy of sciences Beijing 100049 China

In terms of chinese climate-vegetation model based on the classification of plant functional types, to- gether with climatic data from 1951 to 1980 and two future climatic scenarios (SRES-A2 and SRES-B2) in china from the highest and the lowest emission scenarios of greenhouse gases, the distribution patterns of vegetation types and their changes along the Northeast china Transect (NECT) and the North-South Transect of Eastern china (NSTEC) were simulated in order to understand the driving mechanisms of vegetation changes under climatic change. The results indicated that the vegetation distribution patterns would change significantly under future climate, and the major factors driving the vegetation changes were water and heat. However, the responses of various vegetation types to the changes in water and heat factors were obviously different. The vegetation changes were more sensi- tive to heat factors than to water factors. Thus, in the future climate warming will significantly affect vegetation distribution patterns.

关键词： driving mechanism vegetation terrestrial transect climatic change plant functional types

Simulation of aerodynamic performance affected by vortex generators on blunt trailing-edge airfoils

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Science china(Technological sciences) 2010年第1期53卷 1-7页

作者： YANG Ke1,2,ZHANG Lei1,3 & XU JianZhong1,2 1 Institute of Engineering Thermophysics,chinese academy of sciences,beijing 100190,china 2.key laboratory of Wind Energy Utilization,chinese academy of sciences,beijing 100190,china 3 Graduate School of chinese academy of sciences,beijing 100190,china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100190 China2. Key Laboratory of Wind Energy Utilization Chinese Academy of Sciences Beijing 100190 China3. Graduate School of Chinese Academy of Sciences Beijing 100190 China

An investigation was carried out by numerical simulation on a wind turbine airfoil and a blunt trailing-edge airfoil with and without vortex generators (VGs), and the performance of the airfoils was analyzed. By the simulation of airfoil DU 91-W2-250 it was verified that the numerical method and model were credible. Based on this airfoil, a new one with a blunt trailing edge of 6% chord was blended by symmetrically adding thickness, and its characteristics curves were obtained through computing at key angles of attack. Additionally, the pressure distribution on blended airfoil was analyzed by comparing to the airfoil without blend. The interaction of streamwise vortices induced by VGs with trailing vortex or separation vortex was considered, followed by the uncovery of how VGs can suppress the boundary layer separation.

关键词： vortex generators airfoil blunt trailing-edge

NONCONFORMING FINITE ELEMENT APPROXIMATIONS TO THE UNILATERAL PROBLEM

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Journal of Computational Mathematics 1999年第1期17卷 15-24页

作者： Lie-heng Wang(State key laboratory of Scientific and Engeneering Computing, ICMSEC,chinese academy of sciences, beijing 100080, china) chinese Acad Sci State Key Lab Sci & Engn Comp ICMSEC Beijing 100080 Peoples R China

The nonconforming finite element (two Crouzeix-Raviart linear elements and Wilson element) approximations to the unilateral problem are considered. The error bounds for these elements are obtained in the appropriate a... 详细信息

关键词： unilateral problem nonconforming finite element

Interannual variation of annual precipitation and urban effect on precipitation in the beijing region

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Progress in Natural Science:Materials International 2007年第9期17卷 1042-1050页

作者： Yu Shuqiu(State key laboratory on Severe Weather,chinese academy of Meteorological sciences,beijing 100081,china) State key laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081， China

The large scale character of the interannual variation of precipitation and the urban effect on local annual precipitation anomaly are investigated in this paper based on the 1960-2000 annual precipitation observations at 20 stations in the beijing *** results show that:the annual precipitation in the beijing region possesses the large scale variation character with the linear trend of-1.197/10 yr,which corresponds to a total reduction of 27.82 mm in annual precipitation in the 41 years;the local annual precipitation anomalies(percent of the normal 1960-2000)show a positive center near the urban area,*** precipitation island(UPI),whose intensity increases with the linear trend of 0.6621%/10 yr,opposite to the interannual trend of large scale precipitation over the beijing region;changes in the UPI are also associated with the intensity of synoptic processes of precipitation,and when the synoptic processes are strong(wet years),the intensity of UPI strengthens,while the synoptic processes are weak(dry years),and the UPI disappears in the beijing region.

关键词： urban precipitation island effect interannual climate variation precipitation beijing atmospheric science

An integrative estimation model of summer rainfall-band patterns in china

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Progress in Natural Science:Materials International 2007年第3期17卷 280-288页

作者： WEI Fengying (State key laboratory of Severe Weather, chinese academy of Meteorological sciences, beijing 100081, china) State key laboratory of Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081 China

Three variation indices are defined to objectively and quantitatively represent fluctuations of three rainfall-band patterns in summers in china for the period from 1951 to 2005, and the variation features of these indices are analyzed on both of interdecadal and interannual scales. A new method is proposed to establish an integrative estimation model based on the analysis of rainfall-band indices, and the model is applied to air, ocean factors to estimate their roles on variations of three rainfall-band patterns on different time-scales. The tests of estimation effects show that the fluctuations of three rainfall-band patterns are composed of variations on both significant inter-decadal and interannual scales, of which the interannual variation is mainly influenced by the Elnino/Lanina events, the East Asia monsoon and the ridge locations of subtropical high pressures in western pacific, while the interdecadal variation is mainly controlled by the Pacific decadal oscillation and interdecadal oscillations of the Arctic oscillation, ENSO, Nino3 sea surface temperature and summer monsoon. The estimated results from the integrative estimation model of rainfall-band patterns suggest that the way of estimation first according to each time scale of both the interdecadal and interannual scales, then estimating with an integration, which is proposed in this paper, has an obvious improvement on that without separation of time scales.

关键词： rainfall-band pattern interannual variation interdecadal variation integration estimation model.

The effects of K^+ growth conditions on the accumulation of cesium by the bacterium Thermus sp. TibetanG6

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Science china(Life sciences) 2006年第2期49卷 123-129页

作者： WANG Hailei1,2,3, KONG Fanjing1,2,3 & ZHENG Mianping1,2,3 1. R&D Center for Saline Lake and Epithermal Deposits, chinese academy of Geological sciences, beijing 100037, china 2. key Open laboratory of Saline Lake resources and Environment, chinese academy of Geological sciences, beijing 100037, china 3. Institute of mineral resources, chinese academy of Geological sciences, beijing 100037, china R&D Center for Saline Lake Epithermal Deposits Chinese Academy of Geological Sciences Beijing 100037 China key Open laboratory of Saline Lake resources Environment Chinese Academy of Geological Sciences Beijing 100037 China Institute of mineral resources Chinese Academy of Geological Sciences Beijing 100037 China

The accumulation of cesium by the bacterium Thermus sp. TibetanG6 was examined under different K+ growth conditions. The effects of external pH and Na+ on the accumulation of ce-sium were also studied, and the mechanism involved was discussed. K+ regimes played an important role in the accumulation of cesium by the strain TibetanG6. The quantity of cesium accumulated (24 h) was much higher in K+-deficient regime than that in K+-sufficient regime. The pH and Na+ had different effects on the accumulation of cesium in the two K+ regimes. IR spectra analyses indicated that the biosorption is a process of homeostasis with cesium initially accumulated on the cell wall.

关键词： Thermus sp. TibetanG6, cesium, bioaccumulation, K+-growth condition, pH, sodium, IR spectroscopy.

2MASS photometry and age estimation of the globular clusters in the outer halo of M31

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Research in Astronomy and Astrophysics 2012年第2期12卷 115-126页

作者： Jun Ma 1,21 National Astronomical Observatories,chinese academy of sciences,beijing 100012,china 2.key laboratory of Optical Astronomy,National Astronomical Observatories,chinese academy of sciences,beijing 100012,china National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China key laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present the first photometric results in J, H and Ks from 2MASS （Two Micron All Sky Survey） imaging of 10 classical globular clusters （GCs） in the far outer regions of M31. Combined with the V and I photometric data from previous literature, we constructed a color-color diagram between J - Ks and V - Ⅰ. By comparing the integrated photometric measurements with evolutionary models, we estimate the ages of these clusters. The results showed that all of these clusters are older than 3 × 109 yr, and among them four are older than 10 Gyr and the other six have intermediate ages between 3 - 8 Gyr. The masses for these outer-halo GCs are from 7.0 × 104 M to 1.02 × 10^6 M. We argued that GC2 and GC3, whose ages, metallicities and distance moduli are almost the same, were accreted from the same satellite galaxy, if they did not form in situ. The statistical results show that the ages and metallicities of these 10 M31 outer-halo GCs do not vary with projected radial position, and a relationship between age and metallicity does not exist.

关键词： galaxies: halos - galaxies: individual (M31) - star clusters: general

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 1. Institute of mineral resources Chinese Academy of Geological Sciences 100037 Beijing China 2. National Center of Rock and mineral Analysis Chinese Academy of Geological Sciences 100037 Beijing China 3. Resource Assessment Center of Yunnan 650011 Kunming China 4. Institute of Geology and Geophysics Chinese Academy of Sciences 100101 Beijing China 5. chinese academy of Geological sciences 100037 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.

Thermal analysis of the baffle structure of the Solar Space Telescope

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1755-1764页

作者： LI Rong1,2,3 & WANG Sen1,3 1 National Astronomical Observatories,chinese academy of sciences,beijing 100012,china 2 Graduate University of chinese academy of sciences,beijing 100049,china 3 key laboratory of Solar Activity,National Astronomical Observatories of chinese academy of sciences,beijing 100012,china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Laboratory of Solar Activity National Astronomical Observatories of Chinese Academy of Sciences Beijing 100012 China

The SST(Space Solar Telescope) is an astronomical telescope with a primary mirror of 1 m in *** observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray *** baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control *** this study,the compatibility analysis of the thermal effect of baffle structures in SST is *** GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are *** objective and method of the compatibility analysis are *** the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3' tilt angle and 16' tilt angle,and different tilt angles of the outer baffle with a 200 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray *** design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 200 mm,and the outer baffle of tilt angle 3' are successfully *** paper presents the relationship between the thermal control design and stray light elimination plan in the *** aims of the optimal design of the baffle structure of SST are *** thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

关键词： baffle the main baffle the outer baffle GCF BRDF