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fMRI time series analysis based on stationary wavelet and spectrum analysis

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Progress in Natural Science:Materials International 2006年第11期16卷 1171-1176页

作者： ZHI Lianhe~ 1,2.3., ZHAO Xia~4, SHAN Baoci~1**, PENG Silong~5, YAN Qiang~1, YUAN Xiuli~1 and TANG Xiaowei~ 1,6 (1. Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy physics, Chinese Academy of Sciences, Beijing 100049,{2. 2. Graduate School of Chinese Academy of Sciences, Beijing 100049,{2. {3., Zhoukou Normal University, Zhoukou 466100,{2. 4. Research Imaging Center, University of Texas Health Science Center, San Antonio, Texas 782.9, USA 5. National ASIC Design and Engineering Center, Institute of Automation, Chinese Academy of Sciences, Beijing 100049,{2. 6. department of physics, Zhejiang University, Hangzhou 3.002.,{2.) [a]Key Laboratory of Nuclear Analysis Techniques Institute of High Energy Physics Chinese Academy of Sciences Beijing China [b]Graduate School of Chinese Academy of Sciences Beijing China [c]department of physics Zhoukou Normal University Zhoukou China [d]Research Imaging Center University of Texas Health Science Center San Antonio Texas USA [e]National ASIC Design and Engineering Center Institute of Automation Chinese Academy of Sciences Beijing China [f]department of physics Zhejiang University Hangzhou China

The low signal to noise ratio (SNR) of functional MRI (fMRI) prefers more sensitive data analysis methods. Based on stationary wavelet transform and spectrum analysis, a new method with high detective sensitivity was developed for analyzing fMRI time series, which does not require any prior assumption of the characteristics of noises. In the proposed method, every component of fMRI time series in the different time-frequency scales of stationary wavelet transform was discerned by the spectrum analysis, then the components from noises were removed using the stationary wavelet transform, finally the components of real brain activation were detected by cross-correlation analysis. The results obtained from both simulated and in vivo visual experiments illustrated that the proposed method has much higher sensitivity than the traditional cross-correlation method.

关键词： fMRI stationary wavelet transform spectrum analysis data analysis.

A computational investigation of boron-doped chromium and chromium clusters by density functional theory

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Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 812-817页

作者： GE GuiXian1,JING Qun1 & LUO YouHua2.3.1 Key Laboratory of Ecophysics and {2. of physics,Normal College,Shihezi University,Xinjiang 83.003.{3. 2.School of Science,East china University of Science and Technology,Shanghai 2.02.0},{3. 3.Institute of Theoretical physics,School of physics and Information Optoelectronics,Henan University,Kaifeng 475004,{3. 1. Key Laboratory of Ecophysics and department of physics Normal College Shihezi University Xinjiang 832003 China2. School of Science East China University of Science and Technology Shanghai 200237 China3. Institute of Theoretical Physics School of Physics and Information Optoelectronics Henan University Kaifeng 475004 China

The geometries,stabilities and electronic properties of Crn and CrnB(n=2.9) clusters have been systematically investigated by density functional *** results suggest that the lowest energy structures for CrnB clusters can be obtained by substituting one Cr atom in Crn+1 clusters with B *** geometries of CrnB clusters are similar to that of Crn+1 clusters except for local structural *** second-order difference and fragmentation energy show Cr4,Cr6,Cr8,Cr3.,Cr5B and Cr8B cluster are the most stable among these studied *** impurity B increases the stabilities of chromium *** B is doped on the Crn clusters,cluster geometry does dominate positive role in enhancing their *** doped B atom does not change the coupling way of the Cr site in Crn clusters,but breaks the symmetry and the Cr atoms are no longer *** doped B atom increases the total magnetic moments of Crn in most cases.

关键词： Crn and CrnB clusters geometries electronic properties

Perturbations of the Yang-Mills field in the universe

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Research in Astronomy and Astrophysics 2009年第8期9卷 874-882页

作者： Wen Zhao1,2.1 department of physics, Zhejiang University of Technology, Hangzhou {2.0014,{2. W 2.School of physics and Astronomy, Cardiff University, Cardiff, CF2. {2.A, United Kingdom department of physics Zhejiang University of Technology Hangzhou 310014 China School of physics and Astronomy Cardiff University Cardiff CF24 3AA United Kingdom

It has been suggested that the Yang-Mills （YM） field can be a kind of candidate for the inflationary field at high energy scales or dark energy at very low energy scales, which can naturally give the equation of state - 1 〈 ω 〈 0 or ω 〈 - 1. We discuss the zero order and first order Einstein equations and YM field kinetic energy equations of the free YM field models. From the zero order equations, we find that w ＋ 1 ω α^-2. from which it follows that the equation of state of the YM field always goes to - 1, independent of the initial conditions. By solving the first order Einstein equations and the YM field equations, we find that in the YM field inflationary models, the scale-invariant primordial perturbation power spectrum cannot be generated. Therefore, only using this kind of YM field is not enough to account for inflationary sources. However, as a kind of candidate for dark energy, the YM field has the ＇sound speed＇ c^2. = -1/3.〈 0, which makes the perturbation Ф have a damping behavior at large scales. This provides a way to distinguish the YM field dark energy models from other kinds of models.

关键词： cosmology theory- gravitation- methods analytical

A first-principles study of dihydroazulene as a possible optical molecular switch

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Science china(physics,Mechanics & Astronomy) 2011年第3期Mechanics & Astronomy) .卷 437-441页

作者： XIA CaiJuan1, LIU DeSheng2.3.& LIU HanChen1 1 School of Science, Xi’an Polytechnic University, Xi’an 710048, china 2.School of {2., State Key Laboratory of Crystal Materials, Shandong University, Jinan 2.0100, china 3.{3. of {2., Jining University, Qufu 2.3.55, china 1. School of Science Xi’an Polytechnic University Xi’an 710048 China2. School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China3. Department of Physics Jining University Qufu 273155 China

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.

关键词： molecular switch nonequilibrium Green’s function electronic transport density functional theory

Experimental and theoretical study of^(13.C shielding tensors in new-style molybdenum complex

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Science china Chemistry 2004年第3期47卷 214-221页

作者： HOU Guangjin1,2. WANG Liying2. LU Xiaoming3. ZHENG Anmin2. DENG Feng2.&YE Chaohui1,2.1. department of {2., Huazhong University of Science and Technology, Wuhan 43.074,{2. 2. State Key Laboratory of Magnetic Resonance and Atomic and Molecular {2., Wuhan Institute of {2. and Mathematics, Chi-nese Academy of Sciences, Wuhan 43.071,{2. 3. department of Chemistry, Capital Normal University, Beijing 10003.,{2. 1. department of physics Huazhong University of Science and Technology 430074 Wuhan China 2. Chinese Academy of Sciences State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics 430071 Wuhan China 3. department of Chemistry Capital Normal University 100037 Beijing China

13. 2.-PASS spectra of two new cis-dioxo catecholatomolybdenum complexes (NH2.H2.H2.HCH2.2.H+)3.MovO 2.C6H4O2.2. and (NH2.H2.H2.H2.H2.2.H+)3.Mo(v)O2.(C2.2.2.2. have been obtained by solid-state nuclear magnetic resonance (NMR), in which the spinning sidebands were well-separated. The principal components of the 13. shielding tensors were extracted by theoretically fitting the intensities of 13. spinning sidebands. The effects of counter cations on 13. chemical shift isotropy and shielding tensor of cis-dioxo catecholatomolybdenum complex anion [Mo (v)O2.C6H4O2.2.3. were studied, comparing the 13. CSA of those carbon sites in complex anions with that of the counter cations. Based on the known structure of the molybdenum complex crystal, theoretical values of 13. shielding tensors were calculated by the ainitio GIAO method, in comparison with the experimental results.

关键词： NMR, magic angle spinning, chemical shift anisotropy, shielding tensor, cis-dioxo-monomolybdenum.

Lepton flavor violating Z-boson decays at GigaZ as a probe of supersymmetry

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Science china(physics,Mechanics & Astronomy) 2010年第11期53卷 1949-1952页

作者： YANG JinMin 1,2.1 department of physics,Henan Normal University,Xinxiang 45{2.07,{2. 2.Institute of Theoretical physics,Chinese Academy of Sciences,Beijing 100190,{2. 1. department of physics Henan Normal University Xinxiang 453007 China2. Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China

This paper briefly reviews the lepton flavor violating Z-decays at GigaZ as a probe of supersymmetry by focusing on Z → i j in two representative supersymmetric models: the minimal supersymmetric model without R-parity and the supersymmetric seesaw *** work concludes that under the current experimental constraints from LEP and i → j γ,these rare decays can still be enhanced to reach the sensitivity of the ***,supersymmetry can be probed via these decays at GigaZ.

关键词： Z-decay GigaZ supersymmetry

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 {2. of physics, Normal College, Shihezi University, Shihezi 83.003.{3. 2.School of Science, East{3. University of Science and Technology, Shanghai 2.02.0},{3. 3.Institute for Theoretical physics, Henan University, Kaifeng 475004,{3. 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

Image interpretation of weak-coupling N-mer adsorbate's STM system

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Chinese Science Bulletin 1997年第5期42卷 371-374页

作者： HUANG Xintang, Ql Shouren, LI Xinjiao and LI Yongping1 department of physics, Central{2. Normal University, Wuhan 43.070,{2. department of Solid State Electronics, Huazhong University of Science and Technology, Wuhan 43.074,{2. 2. department of physics, University of Science and Technology of{2., Hefei 2.3}02.,{2. department of physics Central China Normal University Wuhan China department of Solid State Electronics Huazhong University of Science and Techndogy Wuhan China department of physics University of Science and Technology of China Hefei China

Up to now, there have been many indistinctive points in the image interpretation of scanning tunnelhng microscopy (STM) system, and the problems have attracted almost all STM scientists’ attention. In 1992. Kenkre proposed the new programme which describes the behaviour of the electrons moving in the STM tunnelling by the method of exciton dynamics, and the programme not only breaks through the restrictions of Tersoff-Hamann theory, but also can be applied conveniently to discussing the effects of the tip structure, adsorbate structure, substrate structure, temperature, tunneling voltage, and the degree of coherence of elec-

关键词： weak-coupling N-mer adsorbates STM image interpretation exciton dynamics method.

Half-lives and fine structure for the α decay of deformed even-even nuclei

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Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 24-31页

作者： NI DongDong1,2.& REN ZhongZhou1,2.3.1department of {2., Nanjing University, Nanjing 2.0093.{2. 2.avli Institute for Theoretical {2.{2., Beijing 100190,{2. 3.enter of Theoretical Nuclear {2., National Laboratory of Heavy-Ion Accelerator, Lanzhou 73.000,{2. Nanjing Univ Dept Phys Nanjing 210093 Jiangsu Peoples R China Kavli Inst Theoret Phys china Beijing 100190 Peoples R China Ctr Theoret Nucl Phys Natl Lab Heavy Ion Accelerator Lanzhou 730000 Peoples R China

The α-decay properties of well-deformed even-even nuclei are systematically calculated within the multichannel cluster model (MCCM). Instead of working in the WKB framework, the quasibound solution to the coupled Schro¨dinger equation is presented with outgoing wave boundary conditions, and the coupling potential is taken into full account in terms of the general quantum theories. The calculated α-decay half-lives are found to agree well with the experimental data with a mean factor of less than 2. The fine structure observed in α decay is also well reproduced by the four-channel microscopic calculation. Very strikingly, the MCCM can give relatively precise descriptions of the branching ratio to excited 4+ states, which is often overestimated in the usual WKB calculations. We expect it to be a significant development of theoretical models toward quantitative descriptions of α transitions to high-spin daughter states.

关键词： α decay half-lives cluster model coupled channel approach