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Estimating surface evapotranspiration using combined MODIS and CBERS-02 data

Science China(Technological Sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2, LIU Qinhuo1, TANG Yong1,3. TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2, ZHENG Hongsheng4 & CHEN Jiayi4 1. State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100101, China 2. Research Center for Remote Sensing and GIS, department of Geography, Beijing Normal University, Beijing 100875, China 3. Graduate University of Chinese Academy of Sciences, Beijing 10003., China 4. department of Atmospheric physics, Peking University, Beijing 100871, China 1. State Key Laboratory of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences 100101 Beijing China2. Research Center for Remote Sensing and GIS Department of Geography Beijing Normal University 100875 Beijing China3. Graduate University of Chinese Academy of Sciences 100039 Beijing China4. Department of Atmospheric Physics Peking University 100871 Beijing China

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02 data were used to produce land use class of Baiyangdian area, Hebei Province, China in the autumn of 2004. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

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Study on the thermal stability and electrical properties of the high-k dielectrics (ZrO_2) _x(SiO_2)_(1-x)

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Science China(Technological Sciences) 2009年第8期52卷 2222-2226页

作者： Lü ShiCheng1,2, YIN Jiang1,2, XIA YiDong2,3. GAO LiGang2,3.& LIU ZhiGuo2,3.1 department of physics, Nanjing University, Nanjing 210093. China 2 National Laboratory of Solid Sate Microstructures, Nanjing University, Nanjing 210093. China 3.department of Materials Science and Engineering, Nanjing University, Nanjing 210093. China 1. department of physics Nanjing University Nanjing 210093 China 2. National Laboratory of Solid Sate Microstructures Nanjing University Nanjing 210093 China 3. department of Materials Science and Engineering Nanjing University Nanjing 210093 China

(ZrO2)x(SiO2)1-x (Zr-Si-O) films with different compositions were deposited on p-Si(100) substrates by using pulsed laser deposition technique. X-ray photoelectron spectra (XPS) showed that these films remained amorphous after annealing at 800℃ with RTA process in N2 for 60 s. The XPS spectra indi- cated that Zr-Si-O films with x=0.5 suffered no obvious phase separation after annealing at 800℃, and no interface layer was formed between Zr-Si-O film and Si substrate. While Zr-Si-O films with x >0.5 suffered phase separation to precipitate ZrO2 after annealing under the same condition, and SiO2 was formed at the interface. To get a good interface between Zr-Si-O films and Si substrate, Zr-Si-O films with bi-layer structure (ZrO2)0.7(SiO2)0.3.(ZrO2)0.5(SiO2)0.5/Si was deposited. The electrical properties showed that the bi-layer Zr-Si-O film is of the lowest equivalent oxide thickness and good interface with Si substrate.

关键词： high-k dielectric film pulsed laser deposition pseudo ternary alloy

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Density functional theory study on the structural and electronic properties of Ag-adsorbed (MgO)_n clusters

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Science China(physics,Mechanics & Astronomy) 2009年第5期52卷 734-741页

作者： GE GuiXian1, JING Qun1 & LUO YouHua2,3.1 Key Laboratory of Ecophysics and department of physics, Normal College, Shihezi University, Shihezi 83.003. China 2 School of Science, East China University of Science and Technology, Shanghai 20023., China 3.Institute for Theoretical physics, Henan University, Kaifeng 475004, China Key Laboratory of Ecophysics and department of physics Normal College Shihezi University Shihezi 832003 China School of Science East China University of Science and Technology Shanghai 200237 China Institute for Theoretical physics Henan University Kaifeng 475004 China

Equilibrium geometries, charge distributions, stabilities and electronic properties of the Ag-adsorbed (MgO)n (n = 1-8) clusters have been investigated by density functional theory (DFT) with generalized gradient approximation (GGA) for exchange-correlation functional. The results show that hollow site is energetically preferred for n≥4, and the incoming Ag atoms tend to cluster on the existing Ag cluster. The Mulliken populations indicate that the interaction between the Ag atom and Magnesia clusters is mainly induced by a weak atomic polarization. The adsorbed Ag atom only causes charge redistributions of the atoms near itself. The effect of the adsorbed Ag atom on the bonding natures and structural features of Magnesia clusters is minor. Furthermore, the investigations on the first energy difference, fragmentation energies and electron affinities show that the Ag(MgO)4 and Ag(MgO)6 are the most stable among studied clusters.

关键词： Ag (MgO)_n clusters geometries electronic properties

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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 13.023.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 physics 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 823.K, σ=2.1 ×10-3.S/cm at 1123.K) is the same as that of CeO2, but smaller than that of Y2O3.stabilized ZrO2. A marked curvature at T = 823.K has been observed in the Arrhenius plot of the bulk conductivity. The activation energy below 823.K is lower than that above 823.K, and the reason has been discussed.

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

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Determination of Young's modulus by nanoindentation

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Science China(Technological Sciences) 2004年第4期47卷 398-408页

作者： MA Dejun1, Chung Wo Ong2, LIU Jianmin1 & HE Jiawen3.1. Surface Engineering Research Institute, CMES, Beijing 100072, China 2. department of Applied physics and Materials Research Center, The Hong Kong Polytechnic University, Hong Kong, China 3. State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, Xian 710049, China 1. Surface Engineering Research Institute CMES 100072 Beijing China 2. department of Applied physics and Materials Research Center The Hong Kong Polytechnic University Hong Kong China 3. State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University 710049 Xi’an China

A methodology for determining Youngs modulus of materials by non-ideally sharp indentation has been developed. According to the principle of the same area-to-depth ratio, a non-ideally pyramidal indenter like a Berkovich one can be approximated by a non-ideally conical indenter with a spherical cap at the tip. By applying dimensional and finite element analysis to the non-ideally conical indentation, a set of approximate one-to-one relationships between the ratio of nominal hardness/reduced Youngs modulus and the ratio of elastic work/total work, which correspond to different tip bluntness, have been revealed. The nominal hardness is defined as the maximum indentation load divided by the cross-section area of the conical indenter specified at the maximum indentation depth. As a consequence, Youngs modulus can be determined from a nanoindentation test only using the maximum indentation load and depth, and the work done during loading and unloading processes. The new method for determining Youngs modulus is referred to as pure energy method. The validity of the method was examined by performing indentation tests on five materials. The experimental results and the standard reference values are in good agreement, indicating that the proposed pure energy method is a promising substitution for the most widely used analysis models at present.

关键词： Young's modulus, nanoindentation, nominal hardness, indentation work.

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Molecular dynamics simulations on the structures and properties of ε-CL-20-based PBXs ——Primary theoretical studies on HEDM formulation design

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Science China Chemistry 2007年第6期50卷 737-745页

作者： XU XiaoJuan1,2, XIAO JiJun1, HUANG Hui3. LI JinShan3.& XIAO HeMing1 1 department of Chemistry, Nanjing University of Science and Technology, Nanjing 210094, China 2 department of Chemistry, Yancheng Teacher’s College, Yancheng 224002, China 3.Institute of Chemical Materials, China Academy of Engineering physics, Mianyang 621900, China department of Chemistry Nanjing University of Science and TechnologyNanjing 210094China department of Chemistry Yancheng Teacher''s CollegeYancheng 224002China Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900

Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703.GAP,HTPB,PEG,and F_(23.4))were *** dynamics(MD)method was employed to investigate their binding energies(E_(bind))20/PEG 20/ Estane5703.≈ epsilon-CL-20/GAP 20/HTPB 20/F_(23.4).By pair correlation function g(r)analyses,hydrogen bonds and vdw are found to be the main interactions between the two *** elasticity and isotropy of PBXs based epsilon-CL-20 can be obviously improved more than pure epsilon-CL-20 *** is not by changing the molecular structures of epsilon-CL-20 for each binder to affect the *** safety and energetic properties of these PBXs are mainly influenced by the thermal capability(C_p^(deg))and density(p)of binders,respectively.

关键词： high energy density material (HEDM), hexanitrohexaazaisowurtzitane (CL-20), polymer bonded explosives (PBXs), molecular dynamics (MD), compatibility, safety properties, mechanical properties, energetic properties

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Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

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Science China(physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2, WANG Chuan1, DENG Zhiwei3. LU Zhiheng4, & LONG Guilu1,5 1. Key Laboratory For Quantum Information and Measurements of MOE, department of physics, Tsinghua University, Beijing 100084,China 2. department of Materials Science and Engineering, Beijing Normal University, Beijing 100875, China 3. Testing and Analytical Center, Beijing Normal University, Beijing 100875,China 4. department of physics, Beijing Normal University, Beijing 100875, China 5. Key Laboratory For atomic and Molecular Nanosciences, Tsinghua University, Beijing 100084,China 1. Key Laboratory For Quantum Information and Measurements of MOE Department of Physics Tsinghua University 100084 Beijing China 2. department of Materials science and Engineering Beijing Normal University 100875 Beijing China 3. Testing and Analytical Center Beijing Normal University 100875 Beijing China 4. department of physics Beijing Normal University 100875 Beijing China 5. Key Laboratory For Atomic and Molecular Nanosciences Tsinghua University 100084 Beijing China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2m+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

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Morphological Evolution of Nb_2O_5 in a Solvothermal Reaction: From Nb_2O_5 Grains to Nb_2O_5 Nanorods and Hexagonal Nb_2O_5 Nanoplatelets

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Journal of Wuhan University of Technology(Materials Science) 2009年第2期24卷 245-248页

作者：胡卫兵 School of Chemical and Environmental Engineering Hubei Institute for Nationalities department of physics Huazhong University of Science and Technology

Novel Nb2O5 nanorods and polygonal Nb2O5 platelets were generated by a simple solvothermal technique. The geometry evolution of the resultant Nb2O5 from amorphous nanoparticles to crystallized particles, from polygonal platelets to well-elongated nanorods was been studied in detail. The processing parameters, including the reaction temperature, reaction time, concentration of the precursors, and pH value of the solution, which affect the shape and size of the nanorods, were investigated. The Nb2O5 nanorods with different aspect ratios were examined by XRD, SEM and TEM. The experimental results show that Nb2O5 nanorod is the orthorhombic structure and well-crystallized. The growth of the nanorods follows their [001] direction. The successful generation of high quality Nb2O5 nanorods is not only important for transition metal oxide research, but also potentially important for further formation of new Nb-based 1-D nanostructures, such as NbS2 and NbN.

关键词： solvothermal morphological evolution Nb2O5 nanomateraials

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α-decay Branching Ratios to Rotational Band of Heavy Even-even and Odd-A Nuclei

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原子核物理评论 2009年第S1期26卷 55-58页

作者： REN Zhong-zhou1,2,3.XU Chang2,3.(1 Center of Theoretical Nuclear physics,National Laboratory of Heavy Ion Research Facility in Lanzhou,Lanzhou 73.000,China 2 department of physics,Nanjing University,Nanjing 210008,China 3.Joint Center for Particle,Nuclear physics and Cosmology,Nanjing 210008,China) Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Research Facility in LanzhouLanzhou 730000China department of physics Nanjing UniversityNanjing 210008China Joint Center for Particle Nuclear Physics and CosmologyNanjing 210008China department of physics Nanjing UniversityNanjing 210008China Joint Center for Particle Nuclear Physics and CosmologyNanjing 210008China

By using a simple barrier penetration approach,we predict the α-decay branching ratios to members of ground-state rotational band of heavy even-even No isotopes. We also extend our approach to calculate the α-decay branching ratios to the rotational band of heavy odd-A nuclei. The theoretical branching ratios of α-decays are found in good agreement with the available experimental data.

关键词： α-decay branching ratio heavy nuclei

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Stochastic resonance in surface catalytic oxidation of carbon monoxide induced by colored noise

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Science China Chemistry 2004年第2期47卷 106-112页

作者： GONG Yubing1,2, HOU Zhonghuai1 & XIN Houwen1 1. department of Chemical physics, University of Science and Technology of China, Hefei 23.026, China 2. department of physics, Yantai Teachers University, Yantai 264025, China 1. department of Chemical physics University of Science and Technology of China 230026 Hefei China 2. department of physics Yantai Teachers University 264025 Yantai China

The dynamical behavior of surface catalytic oxidation reaction of Pt(110)/CO+O2 modulated by colored noise, under the condition of specific temperature, has been investigated when the partial pressure of CO gas is near the supercritical Hopf bifurcation point. By computer simulation the oscillation and stochastic resonance induced by colored noise are observed. The influences of the intensity and correlation time of colored noise on stochastic resonance are discussed. The range of sensitivity of the system to the environmental fluctuation is analyzed.

关键词： colored noise, stochastic resonance, surface catalytic reaction of Pt(110)/CO+O2, supercritical Hopf bifurcation, signal-to-noise ratio (SNR).

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