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Local and non-local sources of airborne particulate pollution at Beijing——The ratio of Mg/Al as an element tracer for estimating the contributions of mineral aerosols from outside Beijing

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Science China Chemistry 2005年第3期48卷 253-264页

作者： HAN Lihui1. ZHUANG Guoshun1.2,3, SUN Yele1.& WANG Zifa3 1. The center for Atmospheric Environmental Study, {1. of Chemistry, Beijing Normal University, Beijing 1.0875, China 2. center for Atmospheric Chemistry Study, {1. of Environmental Science & engineering, Fudan University, Shanghai 200433, China 3. LAPC/NZC, Institute of Atmospheric physics, CAS, Beijing 1.0029, China 1. The center for Atmospheric Environmental Study Department of Chemistry Beijing Normal University 100875 Beijing China 2. center for Atmospheric Chemistry Study Department of Environmental Science & Engineering Fudan University 200433 Shanghai China 3. Institute of Atmospheric physics CAS LAPC/NZC 100029 Beijing China

A new element tracer technique has firstly been established to estimate the contri-butions of mineral aerosols from both inside and outside Beijing. The ratio of Mg/Al in aerosol is a feasible element tracer to distinguish between the sources of inside and outside Beijing. Mineral aerosol, inorganic pollution aerosol mainly as sulfate and nitrate, and organic aerosol are the major components of airborne particulates in Beijing, of which mineral aerosol accounted for 32%―67% of total suspended particles （TSP）, 1.%―70% of fine particles （PM2.5）, and as high as 74% and 90% of TSP and PM2.5, respectively, in dust storm. The sources from outside Beijing contributed 62% （38%―86%） of the total mineral aerosols in TSP, 69% （52%―90%） in PM1., and 76% （59%―93%） in PM2.5 in spring, and 69% （52%―83%）, 79% （52%―93%）, and 45% （7%―79%） in TSP, PM1., and PM2.5, respectively, in winter, while only20% in summer and autumn. The sources from outside Beijing contributed as high as 97% during dust storm and were the dominant source of airborne particulates in Beijing. The contributions from outside Bei-jing in spring and winter are higher than those in summer, indicating clearly that it was related to the various meteorological factors.

关键词： mineral aerosol local sources non-local sources dust storm re-suspended dust element tracer technique.

Inconsistency between WMAP data and released map

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Chinese Science Bulletin 2010年第10期55卷 907-909页

作者： LIU Hao1.& LI TiPei1.2,3 1.Key Laboratory of Particle Astrophysics,Institute of High Energy physics,Chinese Academy of Sciences,Beijing 1.0049,China 2 department of physics & center for Astrophysics,Tsinghua University,Beijing 1.0084,China 3 department of engineering physics & center for Astrophysics,Tsinghua University,Beijing 1.0084,China Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing China department of {1. & center for Astro{1. Tsinghua University Beijing China department of {1. physics & center for Astrophysics Tsinghua University Beijing China

A remarkable inconsistency between the calibrated differential time-ordered data (TOD) of the Wilkinson Microwave Anisotropy Probe (WMAP) mission,which is the input for map-making,and the cosmic microwave background (CMB) temperature maps published by the WMAP team is revealed,indicating that there must exist a serious problem in the map making routine of the WMAP *** inconsistency is easy to be confirmed without the use of WMAP map-making *** view of the importance of this issue for cosmology study,we invite readers to check it by themselves.

关键词：威尔金森微波各向异性探测器 WMAP 地图制作宇宙微波背景有序数据制作软件 TOD CMB

Effects of Ca substitution and surface treatment on electrochemical performances of Ml_(1.0-x) Ca_xNi_(4.0) Co_(0.6) Al_(0.4) hydrogen storage alloy electrodes

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中国有色金属学会会刊：英文版 1999年第3期9卷 487-492页

作者： Chen Weixiang(陈卫祥) 1. Qi Jianqin(祁建琴) 1. Chen Changpin(陈长聘) 2 1. department of {1. 2. department of Materials Science and engineering, Zhejiang University, Hangzhou 31.027, P. R. China Zhejiang Univ Dept Phys Hangzhou 310027 Peoples R China Zhejiang Univ Dept Mat Sci & Engn Hangzhou 310027 Peoples R China

The influences of Ca substitution for Ml and surface treatment on electrochemical performances of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 hydrogen storage alloy electrode were investigated. Ca substitution with x 0.2 could decrease the capacity. It was also found that Ca substitution deteriorates the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. In order to improve these properties of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 alloy electrode, the alloy was treated in 6 mol/L KOH+0.02 mol/L KBH 4 solution. The results showed that the surface treatment improves the electrochemical performances such as the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. :The influences of Ca substitution for Ml and surface treatment on electrochemical performances of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 hydrogen storage alloy electrode were investigated. Ca substitution with x 0.2 could decrease the capacity. It was also found that Ca substitution deteriorates the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode. In order to improve these properties of Ml 1.0- x Ca x Ni 4.0 Co 0.6 Al 0.4 alloy electrode, the alloy was treated in 6 mol/L KOH+0.02 mol/L KBH 4 solution. The results showed that the surface treatment improves the electrochemical performances such as the electrocatalytic activity, high rate dischargeability and cycling durability of the alloy electrode.

关键词： hydrogen storage alloy electrode Ca substitution surface modification

The dynamical properties of Rydberg hydrogen atom near a metal surface

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Science China(physics,Mechanics & Astronomy) 2005年第6期48卷 667-675页

作者： GE Meihua1. ZHANG Yanhui1. WANG Dehua2, DU Mengli3 & LIN Shenglu1.1. College of physics and Electronics, Shandong Normal University, Jinan 25001., China 2. {1. of Mathematics and physics, Shandong Institute of Architecture and engineering, Jinan 25001., China 3. Institute of Theoretical physics, Chinese Academy of Sciences, Beijing 1.0080, China 1. College of physics and Electronics Shandong Normal University 250014 Jinan China 2. department of Mathematics and {1. Shandong Institute of Architecture and Engineering 250014 Jinan China 3. Institute of Theoretical physics Chinese Academy of Sciences 100080 Beijing China

The dynamical properties of Rydberg hydrogen atom near a metal surface are presented by using the methods of phase space analysis and closed orbit theory. Transforming the coordinates of the Hamiltonian, we find that the phase space of the system is divided into vibrational and rotational region. Both the Poincaré surface of section and the closed orbit theory verify the same conclusion clearly. In this paper we choose the atomic principal quantum number as n = 20. The dynamical character of the exited hydrogen atom depends sensitively on the atom-surface distance d. When d is sufficiently large, the atom-surface potential can be expressed by the traditional van der Waals force and the system is integrable. When d becomes smaller, there exists a critical value dc. For d > dc, the system is near-integrable and the motion is regular. While chaotic motion appears for d < dc, and the system tends to be non-integrable. The trajectories become unstable and the electron might be captured onto the metal surface.

关键词： Rydberg hydrogen atom, van der Waals interaction, Poincaré surface of section, closed orbit theory, chaos.

Superconductivity of small metal grains

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Science China(physics,Mechanics & Astronomy) 2005年第4期48卷 431-441页

作者： ZHENG Renrong1.CHEN Zhiqian2 & ZHU Shunquan1.3 1. department of {1., Shanghai Normal University, Shanghai 200234, China 2. department of {1., Southwest Normal University, Chongqing 40071., China 3. department of Computer and Electric Technology, Shanghai Business School, Shanghai 201.00, China 1. department of {1. Shanghai Normal University 200234 Shanghai China 2. department of {1. Southwest Normal University 400715 Chongqing China 3. department of Computer and Electric Technology Shanghai Business School 201400 Shanghai China

The formulas of the energy gap and superconducting critical temperature appropriate for systems with both odd and even number of electrons are derived; the bases of the derivations are BCS theory and energy level statistics. Numerical results qualitatively agree with the experimental phenomena. i.e., the superconductivity of small metallic grains will first enhance then decrease to zero when the grain are getting smaller and smaller. The calculations indicate that the above phenomena happen in the metallic grains belonging to Gaussian Orthogonal Ensemble (GOE) and Gaussian Unitary ensemble (GUE) with zero spin; The superconductivity of small metallic grains in Gaussian Symplectic Ensemble (GSE) will monotonically decrease to zero with the decreasing of the grain size. The analyses suggest that the superconductivity enhancements come from pairing and the balance of the strengths between spin-orbital coupling and external magnetic field. In order to take the latter into account, it is necessary to include the level statistics given by Random Matrix Theory (RMT) in describing small metallic grains.

关键词： size effect, superconductivity enhancements, small metallic grains.

The influence of laser pulse on the photoabsorption spectra of Li atom in strong external field

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Science China(physics,Mechanics & Astronomy) 2006年第2期49卷 178-186页

作者： WANG Dehua1.& LIN Shenglu2 1. School of physics and Electronic {1., Yantai Normal University, Yantai 264025, China 2. department of physics, Shandong Normal University, Jinan 25001., China 1. School of physics and Electronic {1. Yantai Normal University Yantai 264025 China 2. department of {1. Shandong Normal University Jinan 250014 China

Using the time-dependent perturbation theory and the calculation formula of the single- and double-pulse absorption spectra of the atom in strong external fields, we calculate the single- and double-pulse absorption spectra of Li atom in strong magnetic field for different pulse widths. The results show that a pulse of some width can reduce the contribution of the short period closed orbits and eliminate the contribution of the long period orbits. Compared with the single-pulse absorption spectra, we found that for some phase differences, the double-pulse laser absorption spectra are strengthened; while for others, they are reduced. Therefore, we can use the pulse laser to control the oscillation of the absorption spectra and obtain the optimization object.

关键词： laser pulse closed orbit absorption spectra.

Recurrence spectra of He atoms in strong external fields

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Science China(physics,Mechanics & Astronomy) 2004年第4期47卷 477-484页

作者： LIN Shenglu1. LI Hongyun1. WANG Dehua2, ZHAO Wenli1.& GAO Feng1.1. department of {1., Shandong Normal University, Jinan 25001., China 2. department of Mathematics and {1., Shandong Institute of Architecture and engineering, Jinan 25001., China 1. department of {1. Shandong Normal University 250014 Jinan China 2. department of Mathematics and {1. Shandong Institute of Architecture and Engineering 250014 Jinan China

By employing a model potential including the electron exchange energy, we extend the semiclassical closed orbit theory to study the multielectron atoms. Using special region-splitting consistent and iterative method, we figure out the closed orbits in the corresponding classical system and calculate the recurrence spectra of triplet helium atoms in parallel electric and magnetic fields at scaled energy ε=?0.03,n≈40,n=0. The core-scattering effects have been taken into account, which lead to more peaks in the spectra. It has also been confirmed by means of the direct comparison between the spectral portrait in such a plot and those of hydrogen case. In order to compare the theoretic results with experiment, we investigate the closed orbits and recurrence spectra of helium atoms for the similar exchange potential but applied only by single electric field at scaled energy ε=?2.7 case. The spectra are in good agreement with the experimental observation. We conclude that our model is correct and it is necessary to consider the exchange effect for determining the photoabsorption spectra of multielectron atoms in strong external fields.

关键词： exchange potential, recurrence spectra, semiclassical closed orbit theory, core-scattering.

s-ordering operator expansions of quantum-mechanical fundamental representations and their applications

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Science China(physics,Mechanics & Astronomy) 2011年第12期54卷 2150-2154页

作者： FAN HongYi 1.3 , XU YeJun 2 & YUAN HongChun 3,4 1.department of Materials Science and {1., University of Science and Technology of China, Hefei 230026, China 2 department of physics Electronic and {1., Chizhou University, Chizhou 247000, China 3 department of physics, Shanghai Jiao Tong University, Shanghai 200030, China 4 College of Optoelectronic {1., Changzhou Institute of Technology, Changzhou 21.002, China 1. department of Materials Science and {1. University of Science and Technology of China Hefei 230026 China3. Department of Physics Shanghai Jiao Tong University Shanghai 200030 China2. Department of Physics Electronic and Engineering Chizhou University Chizhou 247000 China4. College of Optoelectronic Engineering Changzhou Institute of Technology Changzhou 213002 China

We show that the quantum-mechanical fundamental representations, say, the coordinate representation, the coherent state representation, the Fan-Klauder entangled state representation can be recast into s-ordering operator expansion, which is elegant in form and has many applications in deriving new operator identities. This demonstrates that Dirac's symbolic method can be merged into Newton-Leibniz integration theory in a broad way.

关键词： s-ordering operator expansion operator identities quantum mechanical representation

A fractal study for nucleate pool boiling heat transfer of nanofluids

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Science China(physics,Mechanics & Astronomy) 2010年第1期53卷 30-37页

作者： XIAO BoQi 1., JIANG GuoPing 2 & CHEN LingXia 1.1.department of {1. and Electromechanical engineering, Sanming University, Sanming 365004, China 2 Earthquake engineering Research Test center, Guangzhou University, Guangzhou 51.405, China 1. department of {1. and Electromechanical engineering Sanming University Sanming 365004 China2. Earthquake Engineering Research Test Center Guangzhou University Guangzhou 510405 China

In this paper, a fractal model for nucleate pool boiling heat transfer of nanofluids is developed based on the fractal distribution of nanoparticles and nucleation sites on boiling surfaces. The model shows the dependences of the heat flux on nanoparticle size and the nanoparticle volume fraction of the suspension, the fractal dimension of the nanoparticle and nucleation site, temperature of nanofluids and properties of fluids. The fractal model predictions show that the natural convection stage continues relatively longer in the case of nanofluids. The addition of nanoparticles causes a decrease of the pool nucleate boiling heat transfer. The nucleate pool boiling heat transfer coefficient is decreased by increasing particle concentration. An excellent agreement between the proposed model predictions and experimental data is found. The validity of the fractal model for nucleate pool boiling heat transfer is thus verified.

关键词： nanofluid nucleate pool boiling fractal heat transfer