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Chinese physics B 2015年第5期24卷 451-459页

作者：李若言贺亮孙青纪安春田光善 school of physics Peking University Institut für Theoretische Physik Leopold-Franzens Universitat Innsbruck Department of physics Capital Normal University

Spin-wave excitation plays important roles in the investigation of the magnetic phases. In this paper, we study the spin-wave excitation spectra of two-component Bose gases with spin-orbit coupling in a deep square optical lattice using the spin-wave theory. We find that, while the excitation spectrum of the vortex crystal phase is gapless with a linear dispersion in the vicinity of the minimum point, the spectra of the commensurate spiral spin phase and the skyrmion crystal phase are gapped. Significantly, the spin fluctuations strongly destabilize the classical ground state of the skyrmion phase with the appearance of an imaginary part in the eigenfrequencies of spin excitations. Such features of the spin excitation spectra provide further insights into the exotic spin phases.

关键词： ultracold Fermi gas optical lattice spin-orbit coupling spin excitation spectrum

Neural network prediction of solar cycle 24

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Research in Astronomy and Astrophysics 2011年第4期11卷 491-496页

作者： A.Ajabshirizadeh N.Masoumzadeh Jouzdani Shahram Abbassi Department of physics University of Tabriz school of Astronomy Institute for Research in Fundamental Sciences (IPM) school of physics Damghan University

The ability to predict the future behavior of solar activity has become extremely import due to its effect on the environment near the Earth. Predictions of both the amplitude and timing of the next solar cycle will assist in estimating the various consequences of space weather. The level of solar activity is usually expressed by in- ternational sunspot number （Rz）. Several prediction techniques have been applied and have achieved varying degrees of success in the domain of solar activity prediction. We predict a solar index （Rz） in solar cycle 24 by using a neural network method. The neural network technique is used to analyze the time series of solar activity. According to our predictions of yearly sunspot number, the maximum of cycle 24 will occur in the year 2013 and will have an annual mean sunspot number of 65. Finally, we discuss our results in order to compare them with other suggested predictions.

关键词： Sun: activity -- sunspots -- neural networks -- prediction

Investigation into the rotational bands of ^(185)Pt with the particle-rotor model

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Science China(physics,Mechanics & Astronomy) 2011年第S1期54卷 114-118页

作者： LI GuangShun1,2, ZHOU XiaoHong1,2, ZHANG ShuangQuan3, ZHANG YuHu1 & MENG Jie3 1 Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 730000, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China 3 school of physics and SK Laboratory of Nuclear physics & Technology, Peking University, Beijing 100871, China 1. Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 China 2. Graduate University of Chinese Academy of Sciences Beijing 100049 China 3. school of physics and SK Laboratory of Nuclear physics & Technology Peking University Beijing 100871 China

Theoretical calculations have been performed for the ν9/2+[624](i13/2) and ν7/2-[503](f7/2) bands of 185Pt in the framework of particle-rotor model. The band properties of signature splitting and configuration mixing have been analyzed. The level energy and signature splitting before the band crossing can be well interpreted by introducing triaxiality. The positive-parity yrast band is pro posed to be dominated by the ν9/2+[624](i13/2) component, while the negative-parity band shows strong mixing of ν7/2-[503](f7/2) and ν9/2-[505](h9/2) configurations.

关键词： High-spin states particle-rotor model signature splitting configuration mixing

Frequency-stabilized Yb：fiber comb with a tapered single-mode fiber

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Chinese physics B 2016年第4期25卷 166-170页

作者：谢阳韩海年张龙于子蛟朱政侯磊庞利辉魏志义 school of physics and Optoelectronic Engineering Xidian UniversityXi'an 710071China Beijing National Laboratory for Condensed Matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

We demonstrate a stable Yb：fiber frequency comb with supercontinuum generation by using a specially designed tapered single-mode fiber, in which a spectrum spanning from 500 nm to 1500 nm is produced. The carrier-envelope offset signal of the Yb：fiber comb is measured with a signal-to-noise ratio of more than 40 dB and a linewidth narrower than 120 kHz. The repetition rate and carrier-envelope offset signals are simultaneously phase locked to a microwave reference frequency.

关键词： tapered single-mode fiber supercontinuum generation optical frequency comb

Bipolar outflows as a repulsive gravitational phenomenon——Azimuthally Symmetric Theory of Gravitation(Ⅱ)

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Research in Astronomy and Astrophysics 2010年第11期10卷 1151-1176页

作者： Golden Gadzirayi Nyambuya North-West University(Potchefstroom Campus) School of Physics(Unit for Space Research)

This paper is part of a series on the Azimuthally Symmetric Theory of Gravitation （ASTG）. This theory is built on Laplace-Poisson＇s well known equation and it has been shown that the ASTG is capable of explaining, from a purely classical physics standpoint, the precession of the perihelion of solar planets as a consequence of the azimuthal symmetry emerging from the spin of the Sun. This symmetry has and must have an influence on the emergent gravitational field. We show herein that the emergent equations from the ASTG, under some critical conditions determined by the spin, do possess repulsive gravitational fields in the polar regions of the gravitating body in question. This places the ASTG on an interesting pedestal to infer the origins of outflows as a repulsive gravitational phenomenon. Outflows are a ubiquitous phenomenon found in star forming systems and their true origin is a question yet to be settled. Given the current thinking on their origin, the direction that the present paper takes is nothing short of an asymptotic break from conventional wisdom; at the very least, it is a complete paradigm shift because gravitation is not at all associated with this process, but rather it is thought to be an all-attractive force that only tries to squash matter together onto a single point. Additionally, we show that the emergent Azimuthally Symmetric Gravitational Field from the ASTG strongly suggests a solution to the supposed Radiation Problem that is thought to be faced by massive stars in their process of formation. That is, at ,- 8-10M⊙, radiation from the nascent star is expected to halt the accretion of matter. We show that in-falling material will fall onto the equatorial disk and from there, this material will be channeled onto the forming star via the equatorial plane, thus accretion of mass continues well past the value of - 8-10M⊙, albeit via the disk. Along the equatorial plane, the net force （with the radiation force included） on any material there-on

关键词： stars formation -- stars mass-loss -- stars winds, outflows -- ISM jets and outflows

DFT study of the conductance of molecular wire:The effect of coupling geometry and intermolecular interaction on the transport properties

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Science China Chemistry 2006年第6期49卷 492-498页

作者： QI Yuanhua1,2, GUAN Daren1 & LIU Chengbu1 1. Institute of Theoretical Chemistry, Shandong University, Jinan 250100, China 2. school of physics and Microelectronics, Shandong University, Jinan 250061, China 1. Institute of Theoretical Chemistry Shandong University Jinan 250100 China 2. school of physics and Microelectronics Shandong University Jinan 250061 China

The density functional theory (DFT) combining with the non-equilibrium Green functions (NEGF) method is applied to the study of the electronic transport properties for a Di-thiol-benzene (DTB) molecule coupled to two Au(111) surfaces. The dependence of the transport properties on the bias, the coupling geometry of the molecule-electrode interface, and the intermolecular interaction are examined in detail. The results show that the existence of the hydrogen atom at the end of the DTB molecule would significantly decrease the transmission coefficients, and then the differential conductance (dI/dV). By changing the position of the DTB molecule located between two electrodes a maximum value of calculated current is observed. It is also found that the intermolecular interaction will strongly influence the transport properties of the system studied.

关键词： non-equilibrium Green functions method, transmission spectrum, the molecular projected selfconsistent Hamiltonian, projected density of state.

Studies on the microstructure,optical and electrical properties of organic microcavity devices based on a porous silicon reflector

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Science China(Technological Sciences) 2005年第2期48卷 191-201页

作者： XIONG Zuhong1, FAN Yongliang2, ZHAN Yiqiang2, ZHANG Songtao2, DING Xunmin2 & HOU Xiaoyuan2 1. school of physics, Southwest China-Normal University, Chongqing 400715, China 2. Surface physics Laboratory (National Key Laboratory), Fudan University, Shanghai 200433, China 1. school of physics Southwest China-Normal University 400715 Chongqing China 2. Surface physics Laboratory (National Key Laboratory) Fudan University 200433 Shanghai China

A novel type of microcavity organic light-emitting diode based on a porous silicon distributed Bragg reflector (PS-DBR) has first been achieved and its microstructure, optical, and electrical properties have also been investigated in detail. The microcavity is made up of the central active organic multilayer sandwiched between a top silver film and a bottom PS-DBR, formed by electrochemical etching of p++-Si substrate. The field- emission scanning electron microscopy cross-section images show the nanometer-scale layered structure and flat interfaces inside the microcavity. The reflectivity (relative to an Al mirror) of the PS-DBR is up to 99%, and the stopband is about 160 nm wide. Resonant cavity mode appears as a tip in the reflectivity spectrum of the Si-based organic multilayer films, which is a symbol that the Si-based organic multilayer structure is indeed a microcavity. The peak widths of the electroluminescence (EL) spectra from the cavities emitting green and red light are greatly reduced from 85 nm and 70 nm to 8 nm and 12 nm, respectively, as compared with those measured from non-cavity structures. Note that the EL emission from the cavity devices is single-mode, and the off-resonant optical modes are highly suppressed. Moreover, increases of a factor of about 6 and 4 of the resonant peak intensity from the cavities emitting green and red light are also observed, respectively. In addition, the current-brightness-voltage characteristics and effect parameters on the lifetime of the cavity devices are also discussed. The present technique for obtaining enhanced EL emission from Si-based organic microcavity may also be another novel effective method for realizing Si-based optoelectronics device integration.

关键词： electrochemical etching, Si-based microcavity, electroluminescence, organic light-emitting diodes.

Extracting physics From BESⅢ　Experiment

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Extracting Physics From BESⅢ　Experiment

Surface and Electrical Properties of NiCr Thin Films Prepared by DC Magnetron Sputtering

中国物理学会高能物理分会第七届学术年会

作者： Yajun Mao (school of physics, PKU) for BESⅢCollaboration

来源： cnki会议评论

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Journal of Wuhan University of Technology(Materials Science) 2008年第2期23卷 159-162页

作者： ZHOU Jicheng TIAN Li YAN Jianwu school of physics Science and Technology Central South University Changsha 410083 China

Several batches of NiCr alloy thin films with different thickness were prepared in a multi-targets magnetron sputtering apparatus by changing sputtering time while keeping sputtering target power of Ni and Cr fixed. Then the as-deposited films were characterized by energy-dispersive X-Ray spectrometer （EDX）, Atomic Force Microscope （AFM） and four-point probe （FPP） to measure surface grain size, roughness and sheet resistance. The film thickness was measured by Alpha-Step IQ Profilers. The thickness dependence of surface roughness, lateral grain size and resistivity was also studied. The experimental results show that the grain size increases with film thickness and the surface roughness reaches the order of nanometer at all film thickness. The as-deposited film resistivity decreases with film thickness.

关键词： magnetron sputtering NiCr alloy films surface morphology resistivity