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High-pressure synthesis and properties of CeO_2.ZrO_2.solid solution

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chinese Science Bulletin 2001年第10期46卷 801-806页

作者： XU Dapeng, WANG Quanyong, LU Zhe, LIU Zhiguo, ZHANG Gongmu & SU Wenhui1. Department of physics, Jilin University, Changchun 13002. China 2. International Center for Materials physics, chinese academy of sciences, Shenyang 110015, China 3. Center for condensed matter and Radiation physics, China Center of Advanced Science and Technology (World laboratory), beijing 100080, China Department of physics Jilin University Changchun China International Center for Materials physics Chinese Academy of Sciences Shenyang China Center for condensed matter and Radiation {2. China Center of Advanced Science and Technology (World Laboratory) Beijing China

Using nanoparticles of CeO2.and ZrO2.prepared by the chemical precipitation method as starting materials, the single-phase cubic Ce0.5Zr0.5O2.solid solution (c-Ce0.5Z0.5O2. has been synthesized under 3.1 GPa at 1073 K for the first time. The structure of the c-Ce0.5Zr0.5O2.has not been changed before and after annealing at 773 K for 1 h. Only an unknown EPR signal (g =1.990) has been observed in the c-Ce0.5Zr0.5O2.and not varied after annealing at 773 K for 1 h, which exhibited that there exists no Ce3+ in the c-Ce0.5Zr0.5O2.and the Ce4+ has not been reduced into Ce3+ after annealing. The transport mechanism is ionic for the c-Ce0.5Zr0.5O2. The bulk conductivity (a =1.2.10-5 S/cm at 82. K, σ=2.1 ×10-3 S/cm at 112. K) is the same as that of CeO2. but smaller than that of Y2.3-stabilized ZrO2. A marked curvature at T = 82. K has been observed in the Arrhenius plot of the bulk conductivity. The activation energy below 82. K is lower than that above 82. K, and the reason has been discussed.

关键词： CeO2.ZrO2 nanocrystalline high-pressure and -temperature solid-state reaction solid solution.

Simulation of freezing and melting of soil on the northeast Tibetan Plateau

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chinese Science Bulletin 2011年第20期56卷 2145-2155页

作者： XIA Kun 1,2.3,LUO Yong 2.4,5 & LI WeiPing 2.1 institute of Atmospheric physics,{2.,beijing 10002.,China 2.4} Climate Center,China Meteorological Administration,beijing 100081,China 3Graduate University of {2.,beijing 100049,China 4 Center for Earth System Science,Tsinghua University,beijing 100084,China 5Key laboratory of Earth System Numerical Simulation,Ministry of Education,beijing 100084,China institute of Atmospheric physics Chinese Academy of Sciences Beijing China national Climate Center China Meteorological Administration Beijing China Graduate University of chinese academy of sciences Beijing China Center for Earth System Science Tsinghua University Beijing China Key laboratory of Earth System Numerical Simulation Ministry of Education Beijing China

Using observational data spanning the period from February to December 2.09 and recorded at the Suli station in Qinghai Province,the land-surface model CLM3.0 was employed to simulate the freezing and melting of *** results indicate that the simulated soil temperature is higher than the observed soil temperature and the ultimate thawing date is earlier than the observed date during the melting *** the freezing period,the simulated soil temperature is lower than the observed soil temperature and the ultimate freezing of the deep soil is earlier than that ***,the simulation of freezing is better than that of melting,and the simulation of a shallow layer is better than that of a deeper *** the original CLM3.0,it is assumed that frozen soil begins to melt when the soil temperature exceeds 0C,which is inconsistent with *** critical freeze-thaw temperature was calculated according to thermodynamics equations and the freeze-thaw condition was *** this work,the melting rate for frozen soil was reduced using the modified scheme,and the simulated soil temperature was lowered. Meanwhile,the refreezing of soil during the melting season was well simulated and more closely matched ***,it was found that the rates of melting and freezing differ,with the former being slower than the latter,but refreezing during the melting season is rather quick.

关键词：土壤温度冻结期青藏高原东北部模拟融化观测数据热力学方程表面模型

Possible mechanism of the effect of convection over Asian-Australian “land bridge” on the East Asian summer monsoon onset

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Science China Earth sciences 2006年第11期49卷 1223-1232页

作者： HE Jinhai1, WEN Min2. DING Yihui3 & ZHANG Renhe2.1. Jiangsu Key laboratory of Meteorological Disaster (KLME), Nanjing institute of Meteorology, Nanjing University of Informa- tion Science and Technology, Nanjing 2.0044, China 2. State Key laboratory of Severe Weather (LaSW), chinese academy of Meteorological sciences, beijing 100081, China 3. national Climate Center, chinese Meteorological Administration, beijing 100081, China Jiangsu Key laboratory of Meteorological Disaster (KLME) Nanjing Institute of Meteorology Nanjing University of Information Science and Technology Nanjing China State Key laboratory of Severe Weather (LaSW) Chinese Academy of Meteorological Sciences Beijing China national Climate Center Chinese Meteorological Administration Beijing China

The Asian-Australian “land bridge” is an area with the most vigorous convection in Asian monsoon region in boreal spring, where the onset and march of convection are well associated with the onset of East Asian summer monsoon. The convection occurs over Indo-China Peninsula as early as mid-April, which exerts critical impact on the evolution of monsoon circulation. Before mid-April there are primarily sensible heatings to the atmosphere over Indo-China Peninsula and Indian Peninsula, so the apparent heating ratios over them decrease with height. However, after mid-April it changes into latent heating over Indo-China Peninsula due to the onset of convection, and the apparent heating ratio increases with height in mid- and lower troposphere. The vertical distribution of heating ratio and its differences between Indo-China Peninsula and Indian Peninsula are the key factors leading to the splitting of boreal subtropical high belt over the Bay of Bengal. Such mechanism is strongly supported by the fact that the evolution of the vertical heating ratio gradient above Indo-China Peninsula leads that of 850 hPa vorticity over the Bay of Bengal. Convections over Indo-China Peninsula and its surrounding areas further increase after the splitting. Since then, there is a positive feedback lying among the convective heating, the eastward retreat of the subtropical high and the march of monsoon, which is a possible mechanism of the advance of summer monsoon and convection from Indo-China Peninsula to South China Sea.

关键词： Asian-Australian 'land bridge', tropical convection, Indo-China Peninsula, the splitting of boreal subtropical high belt, East Asian summer monsoon onset.

Estimation on dynamic release of phosphorus from wind-induced suspended particulate matter in Lake Taihu

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Science China Earth sciences 2004年第8期47卷 710-719页

作者： FAN Chengxin1, ZHANG Lu1,2. QIN Boqiang1, WANG Sumin1, HU Weiping1 & ZHANG Chen1 1. Taihu Lake laboratory for Ecosystem Research, Nanjing institute of Geography & Limnology, {2., Nanjing 2.0008, China 2. Graduate School of {2., beijing 100039, China Taihu Lake Lab. for Ecosystem Res. Nanjing Inst. of Geography/Limnology Chinese Academy of Sciences Nanjing 210008 China Grad. Sch. of chinese Acad. of Sci. Beijing 100039 China

Through man-made disturbance experiments, the corresponding relationships be-tween suspended particulate matter (SPM) and wind speed in different lake areas were simu-lated, the physicochemical formal transformation and biological mineralizing and decaying processes of phosphorus in SPM were studied, the contribution of phosphorus transformation to phosphorus loading of the water of Lake Taihu was quantitatively estimated. The results show that about 0.44 t·a-1 loading in Lake Taihu mainly comes from phosphorus-releasing action of SPM in physicochemical transformed to soluble reactive phosphorus (SRP), and the contribution mainly from biological mineralizing and decaying was about 42..8 t·a-1, which is equal to 15.0% of the total external loading of Lake Taihu, namely 4.7—7.5 times as much as SRP loading en-tering the lake by the rivers; thus it is the important source in dynamical internal loading of the lake. The determining factors for dynamical internal loading in lakes are organic phosphorus content in suspended solid and its biological transition availability.

关键词： phosphorus release,wind wave disturbance,particulate decaying,dynamical loading,Lake Taihu.

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, {2., Yangling 712.00, China 2. institute of Agro-Environment and Sustainable Development, chinese academy of Agricultural sciences, beijing 100081, China 3. institute of Geochemistry, {2., Guiyang 550002. China 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.

Temporal study of GRS 1915+105 with rms-flux relation:The importance of magnetic activities in the corona

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Science China(physics,Mechanics & Astronomy) 2010年第S1期53卷 120-124页

作者： HAN Dong1,ZHANG ShuangNan2.& SONG LiMing2.1 Department of Engineering physics & Center for Astrophysics,Tsinghua University,{2. 100084,China 2.Key laboratory of Particle Astrophysics,institute of High Energy physics,chinese academy of sciences,{2. 100049,China Department of Engineering physics & Center for Astrophysics Tsinghua University Beijing China Key laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China

The rms-flux relations for some observations of GRS 1915+105 are *** rms-flux relations of the light curves in only one state,state C or state A,can be described by the simple non-linear model provided Zhang;we thus interpret that such a linear relation reflects the relative importance of magnetic instability for X-ray emission in the corona of the system,compared to the thermal viscous instability for the X-ray emission in the accretion *** rms-flux relations for state B are very scattered,possibly because of the dominance of thermal viscous instability for the X-ray emission in the accretion *** complex rms-flux relations for the observations of transitions between two or three states are caused by the combination of the different rms-flux relations of these *** underlying physical processes are the combination of magnetic topology in the corona and thermal viscous instability in the accretion disk.

关键词： rms-flux relation data analysis GRS 1915+105 magnetic instability

Influence of atmospheric heat sources over the Tibetan Plateau and the tropical western North Pacific on the inter-decadal variations of the stratosphere-troposphere exchange of water vapor

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Science China Earth sciences 2008年第8期51卷 1179-1193页

作者： ZHAN RuiFen1,2.LI JianPing2.1Shanghai Typhoon institute of China Meteorological Administration,Shanghai 2.0030,China 2.tate Key laboratory of Numerical Modeling for Atmospheric {2. and Geophysical Fluid Dynamics(LASG),institute of Atmospheric physics,chinese academy of sciences,beijing 10002.,China Shanghai Typhoon institute of China Meteorological Administration Shanghai China State Key laboratory of Numerical Modeling for Atmospheric sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China

This study investigates the Stratosphere-Troposphere Exchange(STE) of water vapor,emphasizes its interdecadal variations over Asia in boreal summer,and discusses the influences of atmospheric heat sources over the Tibetan Plateau and the tropical western North Pacific(WNP) on them by using the Wei method with reanalysis data from the European Centre for Medium-Range Weather Forecasts(ECMWF) for the years of *** climatology shows that the upward transport of water vapor across the tropopause in boreal summer is the most robust over the joining area of the South Asian Peninsula and Indian-Pacific Oceans(defined as AIPO).The upward transport over there can persistently convey the abundant water vapor into the stratosphere and then influence the distribution and variation of the stratospheric water *** analysis shows that interdecadal variations of the water vapor exchange over the AIPO are significant,and its abrupt change occurred in the mid-1970s and the early *** these three periods,as important channels of the water vapor exchange,the effect of Bay of Bengal-East Asia as well as South China Sea was gradually weakening,while the role of the WNP becomes more and more *** studies show that atmospheric heat sources over the Tibetan Plateau and the WNP are two main factors in determining the interdecadal variations of water vapor *** thermal influences over the Tibetan Plateau and the WNP have been greatly adjusted over the pass 44 *** synthesis influences the interdecadal variations of the water vapor exchange by changing the Asian summer monsoon,but their roles vary with time and *** after 1992.the influence of heat source over the Tibetan Plateau remarkably weakens,while the heat source over the WNP dominates the across-tropopause water vapor *** have important implications for understanding the transport of other components in the atmosphere and estimating the impact of human activities(

关键词： Tibetan Plateau tropical western North Pacific atmospheric heat source STE inter-decadal variations

BUD2.encoding an S-adenosylmethionine decarboxylase,is required for Arabidopsis growth and development

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Cell Research 2006年第5期16卷 446-456页

作者： Chunmin Ge~(1,2.*) Xia Cui~(1,2.*) Yonghong Wang~1 Yuxin Hu~3 Zhiming Fu~1 Dongfen Zhang~(1,2. Zhukuan Cheng~1 Jiayang Li~1 ~1State Key laboratory of Plant Genomics and national Center for Plant Gene Research,{2. of Genetics and Developmental Biology,chinese academy of sciences,beijing 100101,China ~2.raduate School,chinese academy of sciences,beijing 100101,China ~3{2. of Botany,chinese academy of sciences,beijing 100093,China State Key laboratory of Plant Genomics and national Center for Plant Gene Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences Beijing China Graduate School Chinese Academy of Sciences Beijing China institute of Botany Chinese Academy of Sciences Beijing China

Polyamines are implicated in regulating various developmental processes in plants,but their exact roles and how theygovern these processes still remain *** report here an Arabidopsis bushy and dwarf mutant,bud2.which resultsfrom the complete deletion of one member of the small gene family that encodes S-adenosylmethionine decarboxylases(SAMDCs) necessary for the formation of the indispensable intermediate in the polyamine biosynthetic ***2.plant has enlarged vascular systems in inflorescences,roots,and petioles,and an altered homeostasis *** double mutant of bud2.and samdcl,a knockdown mutant of another SAMDC member,is embryo lethal,demonstrat-ing that SAMDCs are essential for plant *** results suggest that polyamines are required for the normalgrowth and development of higher plants.

关键词： BUD2 polyamines embryogenesis plant architecture Arabidopsis

Cloning and expression of putative ethylene receptor genes in soybean plant

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Progress in Natural Science:Materials International 2007年第10期17卷 1152-1160页

作者： Xie Zongming1,2.3, Lei Gang1,2. Wuriyanghan Hada1,2. Tian Aiguo1, Zhang Jinsong1 and Chen Shouyi1(1. national Key laboratory of Plant Genomics, {2. of Genetics and Developmental Biology, chinese academy of sciences, beijing 100101, China 2. Graduate School of chinese academy of sciences, beijing 100039, China 3. Xinjiang academy of Agricultural and Reclamation Science, Shihezi 832.00, China) national Key laboratory of Plant Genomics Institute of Genetics and Developmental Biology Chinese Acad. of Sci. Beijing 100101 China Graduate School Chinese Acad. of Sci. Beijing 100039 China Xinjiang academy of Agricultural and Reclamation Science Shihezi 832000 China

Ethylene plays important roles in plant growth, development, and stress responses, and ethylene receptors have been identified and studied extensively in various plant species. Here we report the cloning of four ethylene receptor genes from soybean, i.e. GmETR1, GmERS1, GmETR2.and GmEIN4. Construction of the phylogenic tree showed that GmETR1 and GmERS1 belong to subfamily I whereas GmETR2.and GmEIN4 belong to subfamily II. The four ethylene receptor genes showed different tissue-specific expression patterns in roots, stems, leaves, cotyledons, flowers, pods and seeds of soybean. These genes were differentially regulated by various abiotic stresses and plant hormones. The possible roles of the four genes in soybean plant were also discussed.

关键词： abiotic stress expression analysis ethylene receptor plant hormone soybean.