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| 1 | 7~Be: A Geochemical Tracer for Seasonal Erosion of Surface Soil in Watershed of Lake Hongfeng, Guizhou, China显示文摘7Be penetrative depth in undisturbed surface soil is within 4mm.^7Be activity shows exponential decrease with soil depth,which is expressed as a diffusion process.7Be penetrative depth in undisturbed surface soil is apparently deeper in the fall (0.22-0.37g cm^-1) than in the spring (0.11-0.28g cm^-2) at the same site;Whereas,^7Be apparent activity at the top of surface soil is higher in the spring (0.3-2.2Bq g^-1)than in the fall (0.2-0.5Bqg^-1) at the same site,The 7Be inventory(189-544Bq m^-2)changes with both locations and seasons.Although the ^7Be flux to the earth's surface increases with amount of precipitation,its maximum inventory in the soil profiles decreases to 30%-40% after the rainy period.Calculated by the diffusion equation,the erosion and accumulation rates of soil particles are agreeable with the observation in situ,Which shows that the rates in fall are 1.5 times those in spring.The eroded soil particles almost all have been removed on the tablelands rathel than transported into the drainage system.This indicates that the soil erosion process in the karst region is only partial transportation within a short distance. | BAI ZHANGUO WAN GUOJIANG WANG CHANGSHENG WAN XI HUANGRONGGUI P.H. SANTSCHIZ and M. BASKARANZ(1￣State Key Lab. Of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences,Guiyang 550002 (China))(2￣Department Of Marine Scien | 1996 | Pedosphere1996，6，1： | 10 |
| 2 | Landuse/landcover changes in Zhangye oasis of Hexi Corridor显示文摘Taking two f alse color composite Landsat 5 TM (Thematic Mapper) images of band 4,3,2 taken in 1995 and 2000 as data resources, this paper carried out study on LUCC of Zhan gye oasis in recent five years by interpretation according to land reso urces classification system of 1:100,000 Resources and Environmental Data base of the Chinese Academy of Sciences. The results show that great changes have taken place in landuse/landcover in Zhangye oasis since 1 995: (1) Changes of landuse structure show that cropland and land for urban c onstruction and built-up area increased, on the contrary, water area an d grassland decreased. These changes reflect the deterioration of eco-e nvironment and the acceleration of urbanization, and also indicate the problems existing in the arrangement of water and land resources betw een the upper and lower reaches of the Heihe River. (2) Regional diff erences of landuse/landcover are evident, characterized by following asp ects: in Sunan County located in Qilian Mountain area, unused land an d grassland decreased, but cropland and land for urban construction an d built-up area increased. In Minle and Shandan counties located in f oothills, unused land, water area and cropland decreased, but grassland and land for urban construction and built-up area increased. In Zhan gye City, Linze County and Gaotai County located in plain area of th e middle reaches of the Heihe River, unused land, water area and gra ssland decreased, while woodland, cropland and land for urban construction and built-up area increased. | MENG Jijun,WU Xiuqin,LI Zhengguo(Department of Urban and Environmental Scien ce, Peking University, Laboratory of Analysis and Simulation of Earth Surface P rocesses, the Ministry of Education, Beijing 100871, China) | 2003 | Journal of Geographical Sciences2003，13，1： | 9 |
| 3 | EFFECT OF INTERPHASE LIFT FORCE ON THE FLUID FLOW IN AN AIR-STIRRED CYLINDRICAL VESSEL显示文摘In the present paper, based on the two-phase model (Eulerian model), the two dimensional fluid flow liz air-stirred water systems is simulated, and the effect of interphase lift force on the fluid flow is specially discussed. In the Eulerian two-phase model, gas and liquid phase are considered to be two different continuous fluids interacting with each other through the finite inter-phase areas. The exchange between the phases is represented by source terms in conversation equations. Turbulence is assumed to be a property of the liquid phase, k - ε model is used to describe the behavior of the liquid phase. The dispersion of phases due to turbulence is represented by introducing a diffusion term in mass consecrvation equation. The contribution of bubble movement to the turbulent energy and its dissipation rate is taken into accounted by adding extra volumetric source terms to the equations of turbulent enemy and its dissipation rate. The comparison between the mathematical simulation and experiment data indicates that the interphase lift force has a big effect on the flow behavior, and considering both drug force and lift force as interphase forces is important to accurately simulate the gas-water two-phase fluid flow in air-stirred systems. The interphase lift force makes bubbles move away from the centerline, the gas concentration is decreased near the centerline, and increased near the wall. The lift force is smaller than drug force at the same place, especially far away from the centerline. | L.F. Zhang K.K. Cai Y. Qu and Y.S. Shen Postdoctoral Fellow of Japan Science Promotion Society Taniguchi Lab., Department of Metallurgy, Graduate School of Engineering, Tohoku University, Sendai980-8579, Japan School of Metallurgy, University of Scien | 2000 | Acta Metallurgica Sinica(English Letters)2000，13，4： | 6 |
| 4 | Positorn annihilation study on point defects in lead tungstate显示文摘A study on point defects in lead tungstate (PbWO4) by using positron annihilation lifetime method is presented. The measurement was carried out for the cases of untreated, vacuum-annealed, oxygen- annealed and La-doped PbWO4 crystals.It was found that the components τ2, which reflect the positron annihilation in point defects, are different from each other for each case. Some tentative models for the defects are discussed. | GU Mu TANG Xue-Feng TONG Hong-Yong LIANG Ling YAO Ming-Zhen CHEN Ling-Yan(Department of Physics, Tongji University, Shanghai 200092)LIAO Jing-Ying SHEN Ding-Zhong YIN Zhi-Wen(Laboratory of Functional Inorganic Materials, the Chinese Academy of Scien | 2000 | Nuclear Science and Techniques2000，11，2： | 2 |
| 5 | Novel Method for Making MicroopticsElements with Continuous Relief显示文摘 | CHEN Bo GUO Lurong TANG Jiyue GUO Yongkang(Information Optics Research Center Sichuan University Chengdu 610064 China)ZHOU Mingbao(The State Key Lab. of optical technologies on microfabrication Institute of Optics & Electronics Chinese Academy of Scien | 1997 | Chinese Journal of Lasers1997，，01： | 1 |
| 6 | A numerical experiment for the simulating effects of Kuwait oil fire and volcanoes in Philippines and Japan on the general circulation and climate显示文摘AnumericalexperimentforthesimulatingeffectsofKuwaitoilfireandvolcanoesinPhilippinesandJapanonthegeneralcirculationandclimateW... | Wang Jian(Beijing Meteorological College, Beijing 100081, China)Zhao Zongci(Chinese Academy of Meteorological Scienes, Beijing 100081, China)Sun Churong(National Meteorological Center, Beijing 100081, China) | 1994 | Journal of Environmental Sciences1994，6，2： | 0 |
| 7 | THE SAND WEDGE AND MIRABILITE OFTHE LAST ICE AGE AND THEIR PALEOCLIMATICSIGNIFICANCE IN HEXI CORRIDOR显示文摘The sand wedges in Hexi Corridor occur in the alluvial gravel stratum of bajada and high terraces. The 14C ages of eolian sand in sand wedges prove that they formed during the Last Ice Age, with the mean annual air temperature about- 5. 6℃. The common 14C and AMS 14C dating ages of terrestrial branch relicts in Huahai clay-mirabilite interlayer are (11600± 280) a B. P. and (1118 ± 54) a B. P. respectively, proving that the drirabilite formed at the cold episode of the Last Glacial Maximum(LGM) and Younger Dryers (YD) in Huahai Lake. It is pointed out that the mean annual air temperature in Hexi Corri- dor during LGM was about - 3℃ - - 7℃, 11℃ - 15℃ lower than that of present, and that during YD was about 0℃ - 2℃, 6℃ - 8℃ lower than at present. This decreasing temperature values are generally coincident with those inferred by pollen, sand wedge and ice core in the northern China, and also with the research on temperature-falling amplitude of middle and high latitude on the Northern Hemisphere recently. | HU Gang, WANG Nai-ang (School of Resources and Environment, Lanzhou University, Lanzhou 730000, P. R. China Cold and Arid Regrons Environment and Engineering Research Institute, the Chinese Academy of Scienes, Lanzhou 730000, P. R. China) | 2001 | Chinese Geographical Science2001，11，1： | 0 |
| 8 | Synthesis of 8-(ω-Chloroalkyl)-dipyrrinones显示文摘 | TU Bin 1, ZHANG Yi 1, WANG Chang qi 2 and MA Jin shi 1,** (1. Center for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, P. R. China 2. Institute of Photographic Chemistry, Chinese Academy of Scien | 2000 | Chemical Research in Chinese Universities2000，16，3： | 0 |
| 9 | Photochromism in CaS:Sm显示文摘The photochromism in CaS:Sm (from white to pink) was observed for the first time byexposing it to ultraviolet light. The experiments results show that the absorption intensity of Sm2+in the range of 500~600um was strongly increased after irradiation. This reveals that there is thevalence changing of Sm. If the sample was excited by visible light again, the pink color turned towhite, indicating that CaS:Sm has potential application in the field of storage material. | Xiao Lin SUN Gut Lan ZHANG Guo Qing TANG Wen Ju CHEN Guang Yan HONG Hong Peng YOU(Optical Information Science Laboratory, Institute of Modern Optics, Nankai University, Tianjin,300071)(Changchun Institute of Applied Chemistry, Chinese Academy of Scien | 1999 | Chinese Chemical Letters1999，10，2： | 0 |
| 10 | Coherent transition radiation from REB in plasma ripple显示文摘The coherent transition-radiation emission from an underdense rela tivistic beam of electrons, travelling through a dense plasma ripple, was studied. The evolution of this radiation field is described by a set of self-consistent pendulum-wave equations. Analytic calculations of the small-signal gain and numerical computations of the nonlinear saturation of this emission are presented. It is shown that such a device may provide a source of tunable coherent radiation ranging from the microwave to the infrared region. | DAI Zhi-Min ZHANG Jin-Song ZHAO Xiao-Feng (National Shanghai Synchrotron Radiation Center Shanghai 201800 Shanghai Institute of Nuclear Research, the Chinese Academy of Sciences, Shanghai 201800 Institute of Plasma Physics, the Chinese Academy of Scien | 2000 | Nuclear Science and Techniques2000，11，1： | 0 |
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