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Electronic structure and magnetism of Fe-doped SiC nanotubes

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Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 1582-1589页

作者： ZHANG WeiHu1,2,3,ZHANG FuChun3,ZHANG ZhiYong4,LU ShuYuan5 & YANG YanNing3 1 Xi’an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi’an 710068,china 2 Graduate university of Chinese Academy of Sciences,Beijing 100049,china 3 college of physics and Electronic Information,Yan’an university,Yan’an 716000,china 4 Information Science and technology Institution,Northwest university,Xi’an 71012.,china 5 Department of Telecommunications,Xi’an Institute of Posts and Telecommunications,Xi’an 71012.,china Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an China Graduate university of Chinese Academy of Sciences Beijing China college of physics and Electronic Information Yan’an University Yan’an China Information Science and technology Institution Northwest University Xi’an China Department of Telecommunications Xi’an Institute of Posts and Telecommunications Xi’an China

The electronic structure and magnetic properties of Fe-doped SiC nanotubes are investigated by using the first-principles method based on density functional theory(DFT) in the local spin density approximation(LSDA).The calculation results indicate that the SiC nanotube of Fe substitution for C exhibits antiferromagnetism while ferromagnetism features prominently when Fe substitutes *** is a kind of half-metal magnetic *** formation energy calculation results show that the formation energy of ferromagnetic structure is 3.2 eV lower than that of antiferromagnetic *** atoms are more likely to replace Si ***-orbit coupling induces electron spin polarization in the ground ***,the doping Fe atoms make relaxation towards the outside of the tube to some extent and larger geometric distortion occurs when Fe substitutes C,but the whole geometric structure of SiC nanotubes is not damaged due to the *** is revealed in the calculation of energy band structure and density of states that more dispersed distribution of energy levels is produced near the Fermi *** Fe substitution for Si,obviously there are spin-split and intense p-d hybrid effects by Si 3p electron spins and Fe 3d electron spins localized at the exchanging interactions between magnetic transitional metal(TM) *** electronic density results indicate that system magnetic moments are mainly generated by the unpaired 3d electrons of Fe *** these results show that the transition metal doping SiC nanotube could be a potential route to fabricating the promising magnetic materials.

关键词： SiC nanotube the first-principles doped magnetic properties

BRST quantization and canonical Ward identity of the supersymmetric electromagnetic interaction system

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Science china(physics,Mechanics & Astronomy) 2007年第3期50卷 339-347页

作者： HUANG YongChang1,3,4, JIANG YunGuo1 & LI XinGuo2,3 1 Institute of Theoretical physics, college of Applied Sciences, Beijing university of technology, Beijing 100022, china 2 Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 730000, china 3 Center of Theoretical Nuclear physics, National Laboratory of Heavy Ion Collisions, Chinese Academy of Sciences, Lanzhou 730000, china 4 china Center of Advanced Science and technology (World Laboratory), Beijing 100080, china Institute of Theoretical physics College of Applied Sciences Beijing University of Technology Beijing China Center of Theoretical Nuclear physics National Laboratory of Heavy Ion Collisions Chinese Academy of Sciences Lanzhou China china Center of Advanced Science and technology (World Laboratory) Beijing China Institute of Modern physics Chinese Academy of Sciences Lanzhou China

According to the method of path integral quantization for the canonical constrained system in Becchi-Rouet-Stora-Tyutin scheme, the supersymmetric electromagnetic interaction system was quantized. Both the Hamiltonian of the supersymmetric electromagnetic interaction system in phase space and the quantization procedure were simplified. The BRST generator was constructed, and the BRST transforma- tions of supersymmetric fields were gotten; the effective action was calculated, and the generating functional for the Green function was achieved; also, the gauge generator was constructed, and the gauge transformation of the system was ob- tained. Finally, the Ward-Takahashi identities based on the canonical Noether theorem were calculated, and two relations between proper vertices and propaga- tors were obtained.

关键词： supersymmetric electromagnetic interaction BRST quantization Ward identity

Carbon Nitride Thin Films Deposited by Plasma Assisted Nd∶YAG Laser Ablation of Graphite in N2+H2 Atmosphere

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Chinese Journal of Lasers 2001年第6期10卷 56-60页

作者： YU Wei WANG Shufang ZHANG Lianshui LI Xiaowei FU Guangsheng (college of physics Science and technology, Hebei university, Baoding 071002, china) 河北大学物理科学与技术学院河北保定 071002

Carbon nitride thin films are deposited on silicon wafers by 532 nm Nd∶YAG laser ablation of graphite in the N 2+H 2 atmosphere assisted by a dc glow discharge plasma at a higher gas pressure of about 4.0 kPa. The properties of the thin films are investigated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). The results show that the deposited films are composed of α-C 3N 4, β-C 3N 4 phase and have the N/C atomic ratio of 2.01. The optical emission spectroscopy (OES) studies indicate that the introduction of a dc glow discharge and the adoption of a higher gas pressure during the film deposition are favorable to the net generation of the atomic N, CN radicals and N + 2 in B 2Σ + u excited state in the plasma, which are considered to play a major role in the synthesis of carbon nitride.

关键词： pulsed laser deposition dc glow discharge carbon nitride

Limit theorems for the weighted occupation time for super-Brownian motions on H~d

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Progress in Natural Science:Materials International 2006年第8期16卷 803-807页

作者： TANG Jiashan (college of Mathematics and physics, Nanjing university of Posts and Telecommunications, Nanjing 210003, china) college of Mathematics and physics Nanjing University of Posts and Telecommunications Nanjing 210003 China

Weighted occupation time processes associated with the super-Brownian motions on hyperbolic spaces are investigated. Longtime behavior and a central limit type theorem for the processes are obtained. For all dimension d≥2, the right normings for two fluctuations are t and t1/2 , and the limit results are the Riemannian measure and some centered Gaussian random measure, respectively.

关键词： super-Brownian motion hyperbolic space occupation time process longtime behavior.

A Study of Intermediate Energy Proton-160 Elastic Scattering Based on the α-Particle Model

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Communications in Theoretical physics 2007年第4期 711-714页

作者： ZHANG Rong~(1,2) YANG Yong-Xu~(1,+) LU Xiao~1 LI Qing-Run~31 Department of physics,guangxi Normal university,guilin 541004,china2 college of Science,china university of Mining and technology,Xuzhou 221008,china3 Institute of High Energy physics,Academia Sinica,Beijing 100039,china Depaxtment of physics Guangxi Normal UniversityGuilin 541004China college of Science China University of Mining and TechnologyXuzhou 221008China Depaxtment of physics Guangxi Normal UniversityGuilin 541004China Institute of High Energy physics Academia SinicaBeijing 100039China

In the framework of KMT multiple scattering theory,an optical potential for the intermediate energyproton-;O elastic scattering is presented based on the α particle model of;*** differential cross sections,theanalyzing powers,and the total cross sections of the intermediate energy proton-;O scattering have been calculated byusing the obtained optical *** main features of the measured angular distributions of the cross section and theanalyzing power can be well *** calculated total cross sections are in good agreement with the experimentaldata at energies below 0.7 GeV and underestimate the data about 8% at higher energies.

关键词： proton-nucleus elastic scattering nuclear α-particle model optical potential

Effects of radial velocity on line profiles and images from the standard thin disk

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Science china(physics,Mechanics & Astronomy) 2010年第1期53卷 155-162页

作者： PAN CaiJuan Department of physics and Telecommunication Engineering, Baise university, Baise 533000, china Center for Astrophysics, university of Science and technology of china, Hefei 230051, china Department of physics and Telecommunication Engineering Baise University Baise China Center for Astrophysics University of Science and Technology of China Hefei China

This paper has derived the general formulae of observed line profiles based on the effects of radial velocity on the standard thin disk fluid around a rotating black hole. Through the ray-tracing method the line profiles of different parameters have been calculated. Comparison of the line profiles with and without a radial velocity shows that the effects of radial velocity on line profiles cannot be neglected in most cases. In both cases the accretive disk imaging shape remains unchanged.

关键词： standard thin disk radial velocity Kerr metric line flux

Phase engineering of Ni-Mn binary layered oxide cathodes for sodiumion batteries

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Journal of Energy Chemistry 2024年第4期91卷 501-511页

作者： Feifei Hong Xin Zhou Xiaohong Liu guilin Feng Heng Zhang Weifeng Fan Bin Zhang Meihua Zuo Wangyan Xing Ping Zhang Hua Yan Wei Xiang college of Materials and Chemistry&Chemical Engineering Chengdu University of TechnologyChengdu 610059SichuanChina college of Chemical Engineering Sichuan UniversityChengdu 610065SichuanChina Research Institute for Electronic Science(RIES)and Division of Information Science and technology Graduate School of Information Science and TechnologyHokkaido UniversityN20W10SapporoHokkaido 001-0020Japan School of Materials Science and Engineering Suzhou University of Science and TechnologySuzhou 215009JiangsuChina Yibin Libode New Materials Co. Ltd.Yibin 644200SichuanChina Engineering Research Center of the Ministry of Education for Advanced Battery Materials School of Metallurgy and EnvironmentCentral South UniversityChangsha 410083HunanChina

Nickel-manganese binary layered oxides with high working potential and low cost are potential candidates for sodium-ion batteries,but their electrochemical properties are highly related to compositional *** composite materials with various phase structures of P3,P2/P3,P2,P2/O3,and P2/P3/O3 were synthesized by manipulating the sodium content and calcination conditions,leading to the construction of a synthetic phase diagram for Na_(x)Ni_(0.25)Mn_(0.75)O_(2)(0.45≤x≤1.1).Then,we compared the electrochemical characteristics and structural evolution during the desodiation/sodiation process of P2,P2/P3,P2/03,and P2/P3/O3-Na_(x)Ni_(0.25)Mn_(0.75)O_(2).Among them,P2/P3-Na0.75Ni0.25Mn0.75O2exhibits the best rate capability of 90.9 mA h g^(-1)at 5 C,with an initial discharge capacity of 142.62 mA h g^(-1)at 0.1 C and a capacity retention rate of 78.25%after 100 cycles at 1 C in the voltage range of 2-4.3 *** observed superior sodium storage performance of P2/P3 hybrids compared to other composite phases can be attributed to the enhanced Na^(+)transfer dynamic,reduction of the Jahn-teller effect,and improved reaction reversibility induced by the synergistic effect of P2 and P3 *** systematic research and exploration of phases in Na_(x)Ni_(0.25)Mn_(0.75)O_(2)provide new sights into high-performance nickel-manganese binary layered oxide for sodium-ion batteries.

关键词： Phase engineering Ni-Mn layered oxide Cathode Sodium-ion batteries

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

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Science china(physics,Mechanics & Astronomy) 2004年第5期47卷 612-620页

作者： ZENG Zhaoquan1,3, WANG Yong2, DU Xiaolong1, MEI Zengxia1, KONG Xianghe3, JIA Jinfeng1, XUE Qikun1 & ZHANG Ze2, 4 1. State Key Laboratory for Surface physics, Institute of physics, Chinese Academy of Sciences, Beijing 100080, china 2. Laboratory of Electron Microscopy, Institute of physics, Chinese Academy of Sciences, Beijing 100080, china 3. college of physics and Engineering, Qufu Normal university, Qufu 273165, china 4. Beijing university of technology, Beijing 100022, china State Key Laboratory for Surface physics Institute of Physics Chinese Academy of Sciences Beijing China college of physics and Engineering Qufu Normal University Qufu China Laboratory of Electron Microscopy Institute of Physics Chinese Academy of Sciences Beijing China Beijing university of technology Beijing China

A Ga wetting layer was used to modify the surface structure of sapphire (0001) substrate to prepare high-quality ZnO film by radio frequency plasma-assisted molecule beam epitaxy. We found that this Ga layer plays a crucial role in eliminating 30 rotation domains, controlling polarity and decreasing defect density in ZnO epilayers, as demonstrated by in situ reflection high energy electron diffraction, ex situ high resolution X-ray diffraction and high resolution cross-sectional transmission electron microscopy. Zn-polar film of ZnO was determined by convergent beam electron diffraction. A Ga bilayer model is proposed to understand the effects of the Ga wetting layer on high-quality ZnO growth.

关键词： Ga wetting layer, sapphire, polarity, defect density, zinc oxide, rf-MBE, RHEED, HRXRD, TEM, CBED.

Online diagnosis of electron excitation temperature in CH_4+H_2 discharge plasma at atmospheric pressure by optical emission spectra

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Science china(physics,Mechanics & Astronomy) 2008年第12期51卷 1892-1896页

作者： CUI JinHua1, XU ZhenFeng2, ZHANG JiaLiang3↑, NIE QiuYue3, XU GenHui4 & REN LongLiang5 1 Faculty of Chemistry and Chemical Engineering, Liaoning Normal university, Dalian 116021, china 2 Technique Center for Modern Education, Liaodong college, Dandong 12.709, china 3 State Key Laboratory for Materials Modification by Laser, Ion and Electron Beams, Dalian university of technology, Dalian 116023, china 4 college of Chemical Engineering, Tianjin university, Tianjin 300072, china 5 Department of physics, Science college, Tianjin university, Tianjin 300072, china Faculty of Chemistry and Chemical Engineering Liaoning Normal University Dalian China Technique Center for Modern Education Liaodong College Dandong China State Key Laboratory for Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Dalian China college of Chemical Engineering Tianjin University Tianjin China Department of physics Science College Tianjin University Tianjin China

Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy. In this study, CH4+H2 dis- charge plasma was on-line diagnosed by optical emission spectra so as to char- acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas. The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure. The diagnostic method is easy, efficient and fairly precise. A serious er- ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

关键词： low temperature plasma electron excitation temperature optical emission spectrum online diagnosis