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Characteristics of fMRI BOLD signal and its neurophysiological mechanism

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Progress in Natural Science:Materials International 2007年第6期17卷 630-638页

作者： Zhao Xiaohu1,2. Wu Yigen3 and Guo Shengli3(1. College of Life Sciences, Zhejiang University, Hangzhou 310058, china 2. Imaging department of Tongji Hospital of Tongji University, Shanghai 2.0065, china 3. College of Mathematics and physics, Nanjing University of Information Science and Technology, Nanjing 2.0044, china) College of Life Sciences Zhejiang University Hangzhou 310058 China Imaging department Tongji Hospital Tongji University Shanghai 200065 China College of Mathematics and physics Nanjing University of Information Science and Technology Nanjing 210044 China

The functional magnetic resonance imaging (fMRI) based on blood oxygen level dependent (BOLD) contrast has emerged as one of the most potent noninvasive tools for mapping brain function and has been widely used to explore physiological, pathological changes and mental activity in the brain. Exploring the nature and property of BOLD signal has recently attracted more attentions. Despite that great progress has been made in investigation of the characteristics and neurophysiological basis, the exact nature of BOLD signal remains unclear. In this paper we discuss the characteristics of BOLD signals, the nonlinear BOLD response to external stimuli and the relation between BOLD signals and neural electrophysiological recordings. Furthermore, we develop our new opinions regarding nonlinear BOLD response and make some perspectives on future study.

关键词： functional magnetic resonance imaging blood oxygen level dependent nonlinear response neural electrophysiological activity.

X-ray spectra induced in highly charged 40Ar^q+ interacting with Au surface

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Science china(physics,Mechanics & Astronomy) 2006年第2期49卷 203-212页

作者： ZHANG Xiao’an1,2. XIAO Guoqing1, YANG Zhihu1, CHEN Ximeng3, ZHAO Yongtao1, LI Fuli4, ZHANG Yinping1, CUI Ying3, ZHANG Hongqiang3, XU Xu3, SHAO Jianxiong3 & ZHAN Wenlong11. Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 730000, china {2., Xianyang Normal University, Xianyang 712.00, china 3. department of Modern physics, Lanzhou University, Lanzhou 730000, china 4. department of Applied physics, Xi’an Jiaotong University, Xi’an 710049, china 1. Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 China 2. department of physics Xianyang Normal University Xianyang 712000 China 3. department of Modern physics Lanzhou University Lanzhou 730000 China 4. department of Applied physics Xi’an Jiaotong University Xi’an 710049 China

By use of optical spectrum technology, the spectra of X-ray induced by highly charged 40Arq+ ions interacting with Au surface have been studied. The results show that the argon Kα X-ray were emitted from the hollow atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ion, with electronic con-figuration 1s2.in its ground state below the solid surface. The yield of the projectile Kα X-ray is related to its initial electronic configuration, and the yield of the target X-ray is related to the projectile kinetic energy.

关键词： highly charged ion hollow multi-electron excitation X- ray.

FeS_(2. (pyrite) electrodeposition thin films and study of growth mechanism

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Science china(Technological Sciences) 2005年第6期48卷 601-611页

作者： DONG Youzhong1, ZHENG Yufeng1, ZHANG Xiaogang2. DUAN He1, SUN Yanfei1 & CHEN Yanhua1 1. department of physics, Xinjiang University, Urumqi 830046,{2. 2. Institute of Applied Chemistry, Xinjiang University, Urumqi 830046,{2. 1. department of physics Xinjiang University 830046 Urumqi China 2. Institute of Applied Chemistry Xinjiang University 830046 Urumqi China

Ferrous sulfide (FeS) thin films were initially electrodeposited on indium-tin oxide (ITO) substrates in the aqueous solution containing iron, sulfur elements and then annealed in the sulfur atmosphere. Thereby, we successfully obtained the single-phased iron pyrite (FeS2. thin films with good quality. The experimental parameters for electrodeposition and the post-growth thermal-dynamical conditions have been calculated so that more details about the effect of thermal-dynamical conditions on the micromechanism concerned with the iron pyrite crystal growth as well as the properties of the samples have been discussed.

关键词： electrodeposition, FeS2 (pyrite), thin films, growth dynamics.

The refined theory of deep rectangular beams based on general solutions of elasticity

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Science china(physics,Mechanics & Astronomy) 2006年第3期49卷 291-303页

作者： GAO Yang1 & WANG Minzhong2.1. College of Science, china Agricultural University, Beijing 100083, china 2. State Key Laboratory for Turbulence and Complex Systems and {2. of Mechanics and Engi- neering Science, Peking University, Beijing 100871, china College of Science China Agricultural University Beijing 100083 China State Key Laboratory for Turbulence Complex Systems department of Mechanics Engineering Science Peking University Beijing 100871 China

The problem of deducing one-dimensional theory from two-dimensional the- ory for a homogeneous isotropic beam is investigated. Based on elasticity theory, the re- fined theory of rectangular beams is derived by using Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. Based on the refined beam theory, the exact equations for the beam without transverse surface loadings are derived and consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beam under transverse loadings are derived directly from the refined beam theory and are almost the same as the governing equations of Timoshenko beam theory. In two ex- amples, it is shown that the new theory provides better results than Levinson’s beam the- ory when compared with those obtained from the linear theory of elasticity.

关键词： deep rectangular beams,the refined theory,Papkovich-Neuber solution,Lur'e method,governing equation

Doubly contracted CI method and applications

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Science china Chemistry 2004年第4期47卷 276-282页

作者： WANG Yubin1, HAN Huixian1, ZHAI Gaohong2.,SUO Bin1 & WEN Zheny1,2.1. Institute of Modern physics, Northwest University, Xian 710069, china 2. Laboratory of Physico-Inorganic Chemistry, {2. of Chemistry, Northwest University, Xian 710069,china Correspondence should be addressed to Wen Zhenyi 1. Institute of Modern physics Northwest University 710069 Xian China 2. Laboratory of Physico-Inorganic Chemistry Department of Chemistry Northwest University 710069 Xi’an China

Based on the hole-particle correspondence an approximate so-called doubly contracted CI scheme is proposed. Examples calculated based on the doubly contracted CI (DCCI) scheme show that the number of configurations after contraction is reduced by three orders of magnitude, and the computation time is reduced by an order of magnitude. The examples also show that compared with experiments the DCCI and uncontracted CI have similar and reasonable accuracy to some spectroscopic parameters.

关键词： doubly contracted CI hole-particle symmetry approximate MRCI

The eastward subtropical countercurrent on isopycnal surface in the western North Pacific

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Science china Earth Sciences 2005年第7期48卷 1065-1073页

作者： LI Rongfeng1, YOU Xiaobao1 & Peter C. Chu2.1. LASG, Institute of Atmospheric physics, Chinese Academy of Sciences, Beijing 10002., china 2. {2. of Oceanography, Naval Postgraduate School, Monterey, CA 93943-512., USA LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China department of Oceanography Naval Postgraduate School Monterey CA 93943-5122 United States

The monthly circulations on isopycnal surface in the western North Pacific are calculated based on the Navy’s Generalized Digital Environmental Model climatological tem- perature and salinity data on a 1/2. × 1/2. grid using a P-vector method. The eastward Sub- tropical Countercurrent (STCC) in the central subtropical gyre has been studied with emphasis on its spatial distribution, vertical structure, volume transport and its nearby eddy phenomenon. The results reproduce the observed feature of STCC, and reveal some new phenomena on isopycnal surface, such as: (1) At σθ = 2..6, there is strong seasonal variability in the distribution, origin and flow status of STCC. There is no STCC in January, February and March. (2. From May to October, a branch of the Kuroshio Countercurrent to the south of Japan merges into STCC, which increases the velocity of STCC and widens its width. (3) The velocity vector field shows that STCC and nearby eddies coexist. (4) The eastward volume transport of STCC across 137.5°E is the strongest in summer with the maximum of 6.9 Sv ( 1 Sv ≡ 106 m3 s?1) in August, and weaker in spring and autumn with 1.7 Sv in April and 1.6 Sv in November. Most of the transports of STCC occur between isopycnal surfaces 2..0σθ and 2..0σθ. (5) The distributions of the zonal flow along 137.5°E show that the flow core of STCC is between 2..3σθ and 2..7σθ .

关键词： P-vector method on isopycnal surface eastward subtropical countercurrent eddy phenomenon.

The refined theory of transversely isotropic piezoelectric rectangular beams

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Science china(physics,Mechanics & Astronomy) 2006年第4期49卷 473-486页

作者： GAO Yang1 & WANG Minzhong2.1. College of Science, china Agricultural University, Beijing 100083, china 2. State Key Laboratory for Turbulence and Complex Systems and {2. of Mechanics and Engi- neering Science, Peking University, Beijing 100871, china 1. College of Science China Agricultural University Beijing 100083 China 2. State Key Laboratory for Turbulence and Complex Systems and department of Mechanics and Engineering Science Peking University Beijing 100871 China

The problem of deducing one-dimensional theory from two-dimensional theory for a transversely isotropic piezoelectric rectangular beam is investigated. Based on the piezoelasticity theory, the refined theory of piezoelectric beams is derived by using the general solution of transversely isotropic piezoelasticity and Lur'e method without ad hoc assumptions. Based on the refined theory of piezoelectric beams, the exact equations for the beams without transverse surface loadings are derived, which consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beams under transverse loadings are derived directly from the refined beam theory. As a special case, the governing differential equations for transversely isotropic elastic beams are obtained from the corresponding equations of piezoelectric beams. To illustrate the application of the beam theory developed, a uniformly loaded and simply supported piezoelectric beam is examined.

关键词： rectangular beams, the refined theory, piezoelectric, transversely isotropic.

X-ray flares of γ-ray bursts: Quakes of solid quark stars?

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Science china(physics,Mechanics & Astronomy) 2009年第2期52卷 315-320页

作者： XU RenXin1 & LIANG EnWei2.1 School of physics and State Key Laboratory of Nuclear physics and Technology, Peking University, Beijing 100871,{2. 2.department of physics, Guangxi University, Nanning 530004,{2. 1. School of physics and State Key Laboratory of Nuclear physics and Technology Peking University Beijing 100871 China 2. department of physics Guangxi University Nanning 530004 China

A star-quake model is proposed to understand X-ray flares of both long and short γ-ray bursts (GRBs) in a solid quark star regime. Two kinds of central engines for GRBs are available if pulsar-like stars are actually (solid) quark stars, i.e., the SNE-type GRBs and the SGR-type GRBs. It is found that a quark star could be solidified about 103 to 106 s later after its birth if the critical temperature of phase transi- tion is a few Metga-electron-volts, and then a new source of free energy (i.e., elastic and gravitational ones, rather than rotational or magnetic energy) could be possible to power GRB X-ray flares.

关键词： γ-rays bursts: X-rays neutron stars elementary particles

Probing proton halo of the exotic nucleus ^(2.)S by elastic electron scattering

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Science china(physics,Mechanics & Astronomy) 2004年第1期47卷 42-51页

作者： WANG Zaijun1 & REN Zhongzhou1’2.1. department of physics, Nanjing University, Nanjing 2.0008,{2. 2. Center of Theoretical Nuclear physics, National Laboratory of Heavy-Ion Accelerator at Lanzhou, Lanzhou 730000,{2. Correspondence should be addressed to Ren Zhongzhou (email: zren@*** zren99@***) Received June 16, 2.03 1. department of physics Nanjing University 210008 Nanjing China 2. Center of Theoretical Nuclear physics National Laboratory of Heavy-Ion Accelerator at Lanzhou 730000 Lanzhou China

Elastic electron scattering on the exotic light nucleus 2.S is investigated in the plane wave Born approximation. The variation of the squared form factors of 2.S with momentum transfer is compared with that of 32.. It is found that the behavior of the form factors near the second minimum (with a moderate momentum transfer) is sensitive to the alteration of the charge density distribution of halo protons in 2.S. This indicates that elastic electron scattering can be a good probe of the structure of proton-halo nuclei.

关键词： elastic electron scattering, cross section, form factor, proton-halo nucleus.