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Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

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Science China Earth sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2.& LI YaoKun3,4 1national Marine Environmental Forecasting Center, beijing 100081, China 2.irst {2. of Oceanography, State Oceanic Administration, Qingdao 2.6061, China 3State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics, {2. of Atmospheric physics, chinese academy of sciences, beijing 10002., China 4Graduate University of chinese academy of sciences, beijing 100049, China national Marine Environmental Forecasting Center Beijing China First institute of Oceanography State Oceanic Administration Qingdao China State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

Modeling the climate effects of different subregional uplifts within the Himalaya-Tibetan Plateau on Asian summer monsoon evolution

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chinese Science Bulletin 2012年第35期57卷 4617-4626页

作者： ZHANG Ran 1,JIANG DaBang 1,2.3,LIU XiaoDong 4 & TIAN ZhiPing 2.5 1 Climate Change Research Center,chinese academy of sciences,beijing 10002.,China 2.Nansen-Zhu Inter{2. Research Centre,institute of Atmospheric physics,chinese academy of sciences,beijing 10002.,China 3 Key laboratory of Regional Climate-Environment Research for Temperate East Asia,chinese academy of sciences,beijing 10002.,China 4 State Key laboratory of Loess and Quaternary Geology,institute of Earth Environment,chinese academy of sciences,Xi’an 710075,China 5 Graduate University of chinese academy of sciences,beijing 100049,China Climate Change Research Center Chinese Academy of Sciences Beijing China Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Key laboratory of Regional Climate-Environment Research for Temperate East Asia Chinese Academy of Sciences Beijing China State Key laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi’an China Graduate University of chinese academy of sciences Beijing China

Considering the different uplifting time of different subregions of the Himalaya-Tibetan Plateau(TP),a series of numerical simulations have been conducted with the Community Atmosphere Model(CAM4) developed at the national Center for Atmospheric Research to explore the effects of the phased tectonic uplift of the Himalaya-TP on the evolution of Asian summer *** results show that the uplifts of the Himalaya and northern TP significantly affect the evolutions of South Asian summer monsoon and northern East Asian summer monsoon *** is,the tectonic uplift of the Himalaya intensifies the South Asian summer monsoon circulation and increases the precipitation in South Asia,whereas the uplift of the northern TP intensifies the northern East Asian summer monsoon circulation and increases the precipitation in northern East *** with previous simulations,current comparative analyses of modeling results for different subregional uplifts within the Himalaya-TP help deepen our understanding of the evolutionary history of Asian monsoons.

关键词：青藏高原隆升喜马拉雅亚洲季风高原气候夏季季风次区域隆起演化建模

Periodicity of Retzius lines in fossil Pongo from South China

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chinese Science Bulletin 2012年第7期57卷 790-794页

作者： HU Rong1,2.3, ZHAO LingXia1,2.& WU XinZhi2.1 Key laboratory of Evolutionary Systematics of Vertebrates, institute of Vertebrate Paleontology and Paleoanthropology, {2., beijing 100044, China 2.laboratory of Human Evolution, institute of Vertebrate Paleontology and Paleoanthropology, {2., beijing 100044, China 3 Graduate University of {2., beijing 100049, China Key laboratory of Evolutionary Systematics of Vertebrates Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing China laboratory of Human Evolution Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China

Periodicity of Retzius lines is a key factor in dental development. In this study, we examined the periodicity of Retzius lines in fossil Pongo from South China using polarized light microscope observation of dental ground sections. The periodicities all of the 15 teeth were 9 d. Comparisons of periodicity were made with extant primates, fossil apes and hominins. Periodicity of fossil Pongo from South China was relatively long but fell within the variation of extant Pongo, Gorilla and modern human, and longer than periodicity of Pan and other extant primates. Fossil Pongo from South China was similar to Lufengpithecus and Sivapithecus, shorter than Gigantopithecus and longer than European and African fossil apes and most early hominins in periodicity. Generally, the periodicities of Asian large-body fossil apes were longer than the periodicities of European and African large-body fossil apes in Miocene. Difference among species and trend of evolution in periodicity were analyzed and discussed. We found that periodicity might gradually increase from Proconsul in early Miocene to several fossil apes in Miocene and then Gigantopithecus in Pleistocene. In addition, this study made correlate analysis between periodicity and body mass respectively in males and females of six extant apes and five fossil apes, and found that periodicity positively correlated with body mass.

关键词：周期性变化中国南方大猩猩化石灵长类动物早中新世类人猿显微镜观察

Kumada chain-growth polycondensation as a universal method for synthesis of well-defined conjugated polymers

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Science China Chemistry 2010年第8期53卷 1620-1633页

作者： GENG YanHou1,HUANG Li1,2.WU ShuPeng1,2.& WANG FoSong1 1State Key laboratory of Polymer physics and Chemistry Changchun {2. of Applied Chemistry,chinese academy of sciences,Changchun 13002.,China 2.raduate University of chinese academy of sciences,beijing 100049,China State Key laboratory of Polymer physics and Chemistry Changchun institute of Applied Chemistry Chinese Academy of Sciences Changchun China Graduate University of chinese academy of sciences Beijing China

Kumada chain-growth polycondensation (KCGP) is a novel method for the synthesis of well-defined conjugated *** the Ni-catalyst can transfer in an intramolecular process to the propagating chain end,the polymerization follows chain-growth *** this newly developed method,various conjugated polymers,such as polythiophenes,poly(p-phenylene) (PPP),polypyrrole (PPy),and polyfluorene with controlled molecular weights and relatively narrow polydispersities (PDIs),have been ***,the polymerizations for poly(3-alkylthiophene)s (P3ATs),PPP,and PPy exhibited quasi-living characteristics,which allows preparing polymer brushes,fully-conjugated block copolymers,and macroinitiators and macro-reactants for the synthesis of rod-coil block *** the current review,the progress in this new area is summarized.

关键词： chain growth polycondensation conjugated polymers Kumada reaction block copolymers polymer brush

Survival of Human Metallothionein-2.Transplastomic Chlamydomonas reinhardtii to Ultraviolet B Exposure

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Acta Biochimica et Biophysica Sinica 2006年第3期38卷 187-193页

作者： Yu-Kun ZHANG~1 Gui-Fang SHEN~2.Bing-Gen RU~1*1 national laboratory of Protein Engineering and Plant Genetic Engineering,Peking University,{2. 100871,China 2.Biotechnology Research institute,the chinese academy of Agricultural sciences,{2. 100081,China national laboratory of Protein Engineering and Plant Genetic Engineering Peking UniversityBeijing 100871 China Biotechnology Research institute the Chinese Academy of Agricultural SciencesBeijing 100081 China

Solar ultraviolet (UV) radiation has a great influence on green organisms,especially planktonlike Chlamydomonas.A human metallothionein-2.gene,which is generally considered to have an anti-radiationfunction by its coding product,was transferred into the chloroplast genome of Chlamydomonas *** dynamically measure the UV effects on Chlamydomonas cells grown in liquid tris-acetate-phosphatemedium,a new method was developed based on the relationship between the chlorophyll content of an algalculture and its absorbance at 570 nm after the 3-(4,5-dimethylthiazol-2.yl)-2.5-diphenyltetrazolium *** this experiment,both the wild-type and the transplastomic *** ceils were cultivated in 96-well microplates containing liquid tris-acetate-phosphate medium in the absence or presence of zinc,copper,cadmium and *** transgenic *** showed a higher resistance than wild-type to UV-Bexposure under all the examined *** in the medium had positive impacts on both types of cells,but had significant influence only on the transplastomic ***,the high cell viability of the trans-genie alga at the end of the 8 h UV-B treatment disappeared after a 2.-h recovery *** did notprotect cells from UV-B damage,but clearly enhanced the growth of both wild-type and transgenic ***.

关键词： ultraviolet B MTT transplastomic Chlamydomonas metallothionein

Influence of magnetic current on the ground state entanglement in an isotropic transverse XY chain

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Progress in Natural Science:Materials International 2007年第10期17卷 1147-1151页

作者： Liu Dan1,2., Zhang Yong3 and Long Guilu1,2.1. Key laboratory for Atomic and Molecular Nanosciences, and Department of {2., Tsinghua University, beijing 100084, China 2. Center of Quantum Information Science and Technology, Tsinghua national laboratory for information Science and Technology, beijing 100084, China 3. institute of physics, School of sciences, beijing University of Posts and Telecommunications, beijing 100876, China) Key laboratory for Atomic and Molecular Nanosciences Department of Physics Tsinghua University Beijing 100084 China Center of Quantum Information Science and Technology Tsinghua National Laboratory for Information Science and Technology Beijing 100084 China institute of physics School of Sciences Beijing University of Posts and Telecommunications Beijing 100876 China

We study the ground state entanglement in a three-qubit XY chain under the influence of a magnetization current. It is found that the ground state changes from a W state to a disentangled state as the magnetic field varies. When the Lagrange multiplier λ>3, namely under a strong magnetic current, the ground state holds onto a W state for a large range of the magnetic field strength. A phase transition to the magnetization-current phase occurs under a certain condition.

关键词： Heisenberg-XY chain magnetic-current phase transition.

A cumulant-based parameter estimation algorithm for near-field sources

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Progress in Natural Science:Materials International 2007年第8期17卷 900-905页

作者： Liang Junli~(1,2.) Yang Shuyuan~(1,2. Zhang Junying~3 (1.institute of Acoustics,chinese academy of sciences,{2. 100080,China 2.Graduate School,chinese academy of sciences,{2. 100039,China 3.national laboratory of Radar Signal Processing,Xidian University,Xi'an 710071,China) institute of Acoustics Chinese Acad. of Sci. Beijing 100080 China Graduate School Chinese Acad. of Sci. Beijing 100039 China national laboratory of Radar Signal Processing Xidian University Xi'an 710071 China

To efficiently use the array aperture and avoid the complicated parameter pairing computation,this paper proposes a new cumulant-based algorithm for localizing near-field narrowband ***,this algorithm proposes a symmetric uniform linear ar- ray (ULA),and constructs three cumulant matrices by using the fourth-order cumulants of some properly chosen sensor outputs;second- ly,unlike the conventional parallel factor (PARAFAC) analysis models in data or subspace domain,it forms a three-way array (TWA) in the fourth-order cumulant domain using the three matrices,and analyzes the uniqueness of its low-rank decomposition;thirdly,it jointly estimates the frequency,the direction-of-arrival (DOA),and the range of each near-field source from the matrices via the low-rank de- composition of the *** simulation results are presented to validate the performance of our proposed method.

关键词： array signal processing localization cumulant parallel factor (PARAFAC) analysis three-way array (TWA)

Simulating the transfer and fate of hexachlorocyclohexane in recent 50 years in beijing, China

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Science China Earth sciences 2005年第12期48卷 2203-2213页

作者： CAO Hongying1, LIANG Tao1 & TAO Shu2.1. institute of Geographical sciences and Natural Resources Research, {2., beijing 100101, China 2. laboratory for Earth Surface Processes, Peking University, beijing 100871, China institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China laboratory for Earth Surface Processes Peking University Beijing China

Taking beijing as a study area, a dynamic fugacity model was used to simulate the transfer and fate of technical HCHs according to the physic-chemical properties of the studying environment and HCH isomers. Dynamic changes of the transfer fluxes and concentrations of HCH isomers during 1952.2.03 were simulated and the model results suggest good agreement between the calculated and measured concentrations of HCH isomers. During 1952.1983, the average input and output amount of HCHs through agricultural application and degradation are 130 t and 150 t respectively. The dominant transfer processes of HCHs in the study area are air-soil deposition, soil erosion and soil-air diffusion, transfer fluxes of these processes are 80 t?a?1, 16 t?a?1 and 11 t?a?1, which account for 92. of total transfer fluxes of HCHs isomers. There were approximately 2.3t HCHs in all environmental compartments of the study area during this period and 97% of which existed in soil compartment. Air and water advection became the dominant input sources of HCHs after 1984 when the application of technical HCHs was prohib-ited, concentration of HCHs quickly descended to a quite low level in several years. Total amount of HCHs isomers remaining in the study area environment now is less than 5% that before 1983, and this percentage may descend to 0.5% after 2. years by prediction.

关键词： fugacity model, hexachlorocyclohexane, compartment, transfer flux, fate.

Isospin-dependent relativistic microscopic optical potential in the Dirac Brueckner-Hartree-Fock method

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Science China(physics,Mechanics & Astronomy) 2004年第2期47卷 189-198页

作者： RONG Jian1 & MA Zhongyu1,2.3 1. China institute of Atomic Energy, beijing 102.13, China 2. Center of Nuclear Theoretical {2., national laboratory of Heavy Ion Accelerator of Lanzhou, Lan-zhou 730000, China 3. institute of Theoretical {2., chinese academy of sciences, beijing 100080, China Correspondence should be addressed to Rong Jian (email: jrong@***) China institute of Atomic Energy Beijing China Center of Nuclear Theoretical physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China institute of Theoretical physics Chinese Academy of Sciences Beijing China

The relativistic microscopic optical potential in the asymmetric nuclear matter is studied in the framework of the Dirac Brueckner-Hartree-Fock method. A new decomposition of the Dirac structure of the nuclear self-energy in nuclear matter is adopted. The self-energy of a nucleon with E > 0 in nuclear matter is calculated with the G matrix in the Hartree-Fock approach. The optical potential of a nucleon in the nuclear medium is identified with the nucleon self-energy. The energy and asymmetric parameter dependence of the relativistic optical potentials for proton and neutron are discussed. The resulting Schroedinger equivalent potentials have reasonable behaviors of the energy dependence. The asymmetric parameter dependence of relativistic optical potentials and Schroedinger potentials are emphasized.

关键词： Dirac Brueckner Hartree-Fock, relativistic microscopic optical potential, asymmetric nuclear matter, isospin-dependence.