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Pure spin polarized transport based on Rashba spin orbit interaction through the Aharonov Bohm interferometer embodied four-quantum-dot ring

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Chinese physics B 2013年第4期22卷 420-428页

作者：吴丽君韩宇 School of Science Shenyang Ligong University department of physics Liaoning University

The spin-polarized linear conductance spectrum and current–voltage characteristics in a four-quantum-dot ring embodied into Aharonov–Bohm （AB） interferometer are investigated theoretically by considering a local Rashba spin–orbit interaction. It shows that the spin-polarized linear conductance and the corresponding spin polarization are each a function of magnetic flux phase at zero bias voltage with a period of 2π, and that Hubbard U cannot influence the electron transport properties in this case. When adjusting appropriately the structural parameter of inter-dot coupling and dot-lead coupling strength, the electronic spin polarization can reach a maximum value. Furthermore, by adjusting the bias voltages applied to the leads, the spin-up and spin-down currents move in opposite directions and pure spin current exists in the configuration space in appropriate situations. Based on the numerical results, such a model can be applied to the design of a spin filter device.

关键词： quantum dot ring Rashba spin–orbit interaction spin-polarized transport "bound states in the continuum" phenomena bias voltage Aharonov–Bohm interferometer

Constraints on smoothness parameter and dark energy using observational H(z) data

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Research in Astronomy and Astrophysics 2011年第2期11卷 125-136页

作者： Hao-Ran Yu1,Tian Lan1,Hao-Yi Wan2,Tong-Jie Zhang1,3 and Bao-Quan Wang4 1 department of Astronomy,Beijing Normal University,Beijing 100875,china 2 Business Office,Beijing Planetarium,Beijing 100044,china 3 Center for High Energy physics,Peking University,Beijing 100871,china 4 department of physics,Dezhou University,Dezhou 253023,china department of Astronomy Beijing Normal University Beijing 100875 China Business Office Beijing Planetarium Beijing 100044 China Center for High Energy physics Peking University Beijing 100871 China department of physics Dezhou University Dezhou 253023 China

With large-scale homogeneity,the universe is locally inhomogeneous,clustering into stars,galaxies and larger *** property is described by the smoothness parameter α which is defined as the proportion of matter in the form of intergalactic *** we consider the inhomogeneities over a small scale,there should be modifications of the cosmological distances compared to a homogenous *** and Roeder developed a second-order ordinary differential equation（D-R equation） that describes the angular diameter distance-redshift relation for inhomogeneous cosmological ***,we may obtain the D-R equation for observational H（z） data（OHD）.The density-parameter ΩM,the state of dark energy ω,and the smoothness-parameter α are constrained by a set of OHD in a spatially flat XCDM universe as well as a spatially flat XCDM *** using a χ2 minimization method,we get α = 0.81＋0.19-0.20 and ΩM = 0.32＋0.12-0.06 at the 1σ confidence *** we assume a Gaussian prior of ΩM = 0.26 ± 0.1,we get α = 0.93＋0.07-0.19 and ΩM = 0.31＋*** the XCDM model,α is constrained to α≥ 0.80 but ω is weakly constrained around-1,where ω describes the equation of state of the dark energy（pX = ωρX）.We conclude that OHD constrains the smoothness parameter more effectively than the data of SNe Ia and compact radio sources.

关键词： cosmology -- dark energy -- cosmological parameters

Microstructure evolution of an Ni-Cr-Co base superalloy heat-treated at 704 and 760℃

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Rare Metals 2003年第3期22卷 169-174页

作者： ZHAOShuangqun XIEXishan HighTemperatureMaterialsResearchlaboratories UniversityofScienceandTechnologyBeijingBeijing100083China；DepartmentofPhysicsNingxiaUniversityYinchuan750021China HighTemperatureMaterialsResearchLaboratories UniversityofScienceandTechnologyBeijingBeiiing100083China

Thermodynamic calculation, SEM (scanning electron microscopy), TEM(transmission electron microscopy), XRD (X-ray diffraction), phase extraction, and chemical analysiswere employed to study the phase stability and phase precipitation in a new Ni-Cr-Co basesuperalloy heat-treated at 704 and 760 ℃ for a long tune. The results show that the precipitates ofthis new alloy heat-treated at standard annealing condition and heat-treated at 704 and 760℃ for atime up to 2000 h are γ′, MC, M_(23)C_6, and M_6C, and η phase forms at grain boundaries and inmatrix of samples heat-treated at 760 ℃ as well. The mass fractions of γ′ (+η), MC, M_(23)C_6,and M_6C in all samples have no large changes with an increase in aging time, but γ′ precipitatesgrow obviously. The γ′-to-η transformation in the samples heat-treated at 760℃ took place withincreasing aging time. The η precipitates form a Widmanstaetten pattern and the γ′ phases haveremelted partly in the samples heat-treated at 760 ℃. The alloy maintains a better microstructuralstability during prolonged aging at 704 ℃, but a worse microstructural stability during prolongedaging at 760 ℃.

关键词： Ni-Cr-Co base superalloy thermodynamic calculation microstructuralstability precipitate phase analysis

Searching for Top Squark at Hadron Colliders

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高能物理与核物理 2002年第Z1期26卷 25-33页

作者： YANG Jin-Min Young Bing-Lin (Institute of Theoretical physics, CAS, Beijing 100080, china)(department of physics and Astronomy, Iowa State University, Ames, Iowa 50011, US A) Institute of Theoretical physics CAS Beijing 100080 China Institute of Theoretical physics CAS Beijing 100080 China department of physics and Astronomy Iowa State University Ames Iowa 50011 USA

In this talk we briefly summarise our recent study(hep-ph/0007165)on searching fortop squark at hadron *** light top-squark(stop)if produced in hadron colliders in theform of the (?)(?) pair and decaying through the l... 详细信息

关键词：高能物理核物理 QCD Searching for Top Squark at Hadron Colliders pair LHC

FRACTAL RESEARCH ON CRACKS PROPAGATION OF GAS PIPELINE X52 STEEL WELDING LINE UNDER HYDROGEN ENVIRONMENT

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Acta Metallurgica Sinica(English Letters) 2001年第3期14卷 219-226页

作者： S.H. Dong , Y.M. Lu, Y. Zhang and Q. Wu (Mechanics Electronic department, University of Petroleum, Beijing 102200, china) (department of Material physics, University of Science and Technology Beijing, Beijing 100083, china) (Yan Shan University, Qinhuangd Dept. of Mech. Electron. Univ. of Pet. Beijing 102200 China

Based on the theory of hydrogen enhanced localized plasticity of the hydrogen induced cracking and the consideration of the effect of the residual stress produced by eliminated stress heat-treatment, a fractal model of hydrogen induced cracking was presented, and the relationships among the effective surface energy (H), fractal dimension D and stress intensity factor of hydrogen induced cracking, KIH, for welding pipeline under hydrogen environment was set up, from which the relationship of D and KISCC was obtained. The model has been verified experimentally to be correct.

关键词： Crack initiation Electric arc welding Environmental impact Fractals Hydrogen

A Series of Soliton-like and Double-like Periodic Solutions of a (2+1)-Dimensional Asymmetric Nizhnik-Novikov-Vesselov Equation

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Communications in Theoretical physics 2004年第11期42卷 655-660页

作者： CHEN Yong,~(1,3,4, WANG Qi~(2,4) LI Biao~(2,4) ~1department of Mathematics,Ningbo University,Ningbo 315211,china ~2department of Applied Mathematics,Dalian University of Technology,Dalian 116024,china ~3department of physics,Shanghai Jiao Tong University,Shanghai 200030,china ~4Key Laboratory of Mathematics Mechanization~ the Chinese Academy of Sciences,Beijing 100080,china department of Mathematics Ningbo University Ningbo 315211 China department of physics Shanghai Jiao Tong University Shanghai 200030 China Key Laboratory of Mathematics Mechanization the Chinese Academy of Sciences Beijing 100080 China department of Applied Mathematics Dalian University of Technology Dalian 116024 China

We generalize the algebraic method presented by Fan [***.A:***.36 (2003) 7009)] to uniformlyconstruct a series of soliton-like solutions and double-llke periodic solutions for nonlinear partial differential equations(NPDE),As an application of the method,we choose a (2+1)-dimensional asymmetric Nizhnik-Novikov-Vesselov equa-tion and successfully construct new and more general solutions including a series of nontraveling wave and coefficientfunctions’ soliton-like solutions,double-like periodic and trigonometric-like function solutions.

关键词： symbolic computation soliton-like solution Weierstrass and Jacobi elliptic functions periodic solution

Interaction of two two-level atoms with SU (1, 1 ) coherent states

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Chinese Journal of Lasers 1994年第6期B3卷 521-528页

作者： SONG Tongqiang FENG Jian WANG Wenzheng XU Jingzhi(l) Institufe of Optical Communicafion, Uaocbeng Teacborsl College,Shandong 252059, china)(2) department of physics, tiaocbong Teacborsl College,Shandong 252059, china) Liaocheng Teachers' Coll Liaocheng China

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Ｉｎｔｅｒａｃｔｉｏｎｏｆｔｗｏｔｗｏ－ｌｅｖｅｌａｔｏｍｓｗｉｔｈＳＵ（１，１）ｃｏｈｅｒｅｎｔｓｔａｔｅｓ￥ＳＯＮＧＴｏｎｇｑｉａｎｇ；ＦＥＮＧＪｉａｎ；ＷＡＮＧＷｅｎｚｈｅｎｇ；ＸＵＪｉｎｇｚｈｉ（ｌ）ＩｎｓｔｉｔｕｆｅｏｆＯｐｔ...

关键词： coherent state squeezed vacuum state two--photon TC model

Analytical Potential Energy Function,Spectroscopic Constants and Vibrational Levels for A^1E_u^+ State of Dimer ~7Li_2

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Communications in Theoretical physics 2007年第12期48卷 1081-1087页

作者： SHI De-Heng~1 MA Heng~1 SUN Jin-Feng~(1,2)and ZHU Zun-Lue~1~1 College of physics & Information Engineering,Henan Normal University,Xinxiang 453007,china~2 department of physics & Electron Science,Luoyang Normal University,Luoyang 471022,china College of physics & Information Engineering Henan Normal University Xinxiang 453007 China department of physics & Electron Science Luoyang Normal University Luoyang 471022 China

The symmetry-adapted-duster configuration-interaction method is used to investigate the spectroscopicproperties of ~7Li_2(A^1∑_u^+) over the internuclear distance ranging from 2.4ao to *** complete potential energycurves are calculated at numbers of basis *** the ab initio calculated points are fitted to the analytic MurrellSorbie function and then employed to compute the spectroscopic *** comparison,the spectroscopic constantsreproduced by the potential attained at D95(3df,3pd) are found to be very close to the experiments,a^d the values (T_e,D_e,R_e,ω_e,ω_eχ_e,α_e and B_e) are of 1.732 93 eV,1.161 36 eV,0.313 27 nm,251.95 cm^(-1),1.623 cm^(-1),0.005 35 cm^(-1),and0.490 cm^(-1),*** the potential obtained at D95(3df,3pd),the totally 75 vibrational states are found whenJ=*** vibrational levels,the classical turning points and the inertial rotation constants of the first 68 vibrationalstates are calculated for the first time and compared with the available *** agreement is *** centrifugal distortion constants of the first 32 vibrational states are also reported for the first *** reasonabledissociation limit for ~7Li_2(A^1∑_u^+) is deduced using the calculated results at present.

关键词： analytic potential energy function harmonic frequency dissociation energy vibrational level classical turning point

Performance of Polarizers and Coupler in an All Polarization Maintaining Fiber Interferometer

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Chinese Journal of Lasers 2000年第2期9卷 148-154页

作者： CHEN Zhe LIAO Yanbiao HU Yongming LI Xiujian MENG Zhou ( department of Electronic Engineering, Tsinghua University, Beijing 100084, china department of Applied physics, National University of Defense Technology, Changsha 410073, china ) 清华大学北京 100084 国防科学技术大学湖南长沙

It is given mathematical models and analyze the performance of polarizers and coupler in an all polarization maintaining fiber (PMF) Michelson interferometer. The optical coherent signal to noise ratio (CSNR) of the i... 详细信息

关键词： polarization maintaining fiber interferometer optical fiber polarizer optical fiber coupler Jones matrix