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Linear and Nonlinear Optical Absorptions of a Donor Impurity in Spherical Quantum Dots

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Communications in Theoretical Physics 2009年第7期52卷 155-158页

作者： xie wen-Fang School of Physics and Electronic Engineering Guangzhou University Guangzhou 510006 China

An investigation of the optical properties of a hydrogenic donor in spherical parabolic quantum dots hasbeen performed by using the matrix diagonalization *** optical absorption coefficient between the ground(L=0) and the first excited state (L=1) have been examined based on the computed energies and wave *** results are presented as a function of the incident photon energy for the different values of the confinement *** results show the effects of the quantum size and the impurity on the optical absorption coefficient of a donorimpurity quantum dot.

关键词： quantum dot optical absorption

A Study of Confined Helium Atom

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Communications in Theoretical Physics 2007年第2X期48卷 331-334页

作者： xie wen-Fang Department of Physics Guangzhou University Guangzhou 510006 China

The helium atom confined by a spherical parabolic potential well is studied employing the adiabatic hyperspherical approach method. Total energies of the ground and three low-excited states are obtained as a function of the confined potential radii. We find that the energies of a spherical parabolic potential well are in good agreement with those of an impenetrable spherical box for the larger confined potential radius. We find also that the confinement may cause accidental degeneracies between levels with different low-excited states and the inversion of the energy values. The results for the three-dimensional spherical potential well and the two-dimensional disc-like potential well are compared with each other. We find that the energy difference between states in a two-dimensional parabolic potential is also obviously larger than the corresponding levels for a spherical parabolic potential.

关键词： helium atom energy spectrum

Microstructure and nanoindentation hardness of shot-peened ultrafine-grained low-alloy steel

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Journal of Iron and Steel Research International 2019年第5期26卷 472-482页

作者： Xiao-wei Feng juan xie wen-ying Xue Yong-feng Shen Hong-bo Wang Zhen-yu Liu Institute of Systems Engineering of China Academy of Engineering Physics Mianyang 621999 Sichuan China Key Laboratory for Anisotropy and Texture of Materials (MOE) School of Materials Science and Engineering Northeastern University Shenyang 110819 Liaoning China The State Key Lab of Rolling and Automation Northeastern University Shenyang 110819 Liaoning China

The effect of shot peening (SP) on microstructure and hardness of ultrafine-grained (UFG) low-alloy steel was investigated. With increasing shot-peening time from 0.5 to 1.5 h, grain size of UFG low-alloy steel decreases from 400 to 280 nm at surface whilst that of the layer with a depth of 160μm decreases from (230 ± 15) to (75 ± 5) nm. Interestingly, nanoindentation shows that hardness increases linearly with increasing the SP duration, reaching a value as high as (7.10 ± 0.1) GPa at the depth of 160 μm after the SP duration of 1.5 h. The thickness of the SP treated layer is measured as^300 μm. The Hall-Petch (H-P) relationship was established for the hardening layer. Correspondingly, abrasion resistance should be ~51% higher than that of as-prepared UFG low-alloy steel. As shown in SP processing, grain refinement is the key factor responsible for the strengthening of the studied steel.

关键词： Low-alloy steel Shot peening Grain refinement Nanoindentation Hardness

Study on Vortex-Induced Motions of A New Type of Deep Draft Multi-Columns FDPSO

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China Ocean Engineering 2018年第1期32卷 1-13页

作者： GU Jia-yang xie Yu-lin ZHAO Yuan LI wen-juan TAO Yan-wu HUANG Xiang-hong Marine Equipment and Technology Institute Jiangsu University of Science and Technology Zhenjiang 212003 China School of Naval Architecture and Marine Engineering Jiangsu University of Science and Technology Zhenjiang 212003China Marine Design & Research Institute of China Shanghai 200011 China

A numerical simulation and an experimental study on vortex-induced motion（VIM） of a new type of deep draft multi-columns floating drilling production, storage and offloading（FDPSO） are presented in this paper. The main dimension, the special variable cross-section column and the cabin arrangement of the octagonal pontoon are introduced based on the result. The numerical simulation is adapted to study the effects of current incidence angles and reduced velocities on this platform’s sway motion response. The 300 m water depth equivalent truncated mooring system is adopted for the model tests. The model tests are carried out to check the reliability of numerical simulation. The results consist of surge, sway and yaw motions, as well as motion trajectories. The maximum sway amplitudes for different types of offshore platform is also studied. The main results show that the peak frequencies of sway motion under different current incidence angles and reduced velocities vary around the natural frequency. The analysis result of flow field indicates that the change of distribution of vortex in vertical presents significant influences on the VIM of platform. The trend of sway amplitude ratio curve of this new type FDPSO differs from the other types of platform. Under 45° current incidence angle, the sway amplitude of this new type of FDPSO is much smaller than those of other types of offshore platform at 4.4 ≤ V;≤ 8.9. The typical ‘8’ shape trajectory does not appear in the platform’s motion trajectories.

关键词： FDPSO multi-columns vortex-induced motion(VIM) model tests variable cross-section column

Interference of the East Asian Winter Monsoon in the Impact of ENSO on the East Asian Summer Monsoon in Decaying Phases

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Advances in Atmospheric Sciences 2014年第2期31卷 344-354页

作者： FENG juan CHEN wen Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences

The variability of the East Asian winter monsoon （EAWM） can be divided into an ENSO-related part （EAWMEN） and an ENSO-unrelated part （EAWMres）.The influence of EAWMres on the ENSO-East Asian summer monsoon （EASM） relationship in the decaying stages of ENSO is investigated in the present *** achieve this,ENSO is divided into four groups based on the EAWMres：（1） weak EAWMres-E1Ni（n）o （WEAWMres-EN）; （2） strong EAWMres-E1Ni（n）o （SEAWMresEN）; （3） weak EAWMres-La Ni（n）a （WEAWMres-LN）; （4） strong EAWMres-La Ni（n）a （SEAWMres-LN）.Composite results demonstrate that the EAWMres may enhance the atmospheric responses over East Asia to ENSO for WEAWMres-EN and *** corresponding low-level anticyclonic （cyclonic） anomalies over the western North Pacific （WNP） associated with El Ni（n）o （La Ni（n）a） tend to be ***,this feature may persist into the following summer,causing abundant rainfall in northern China for WEAWMres-EN cases and in southwestern China for SEAWMres-LN *** contrast,for the SEAWMres-EN and WEAWMres-LN groups,the EAWMres tends to weaken the atmospheric circulation anomalies associated with E1 Ni（n）o or La Ni（n）*** these cases,the anomalous WNP anticyclone or cyclone tend to be reduced and confined to lower latitudes,which results in deficient summer rainfall in northern China for SEAWMres-EN and in southwestern China for *** study suggests that anomalous EAWMres may have an effect on the extra-tropical sea surface temperature anomaly,which persists into the ensuing summer and may interfere with the influences of ENSO.

关键词： East Asian winter monsoon ENSO East Asian summer monsoon

Reducible solution to a quaternion tensor equation

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Frontiers of Mathematics in China 2020年第5期15卷 1047-1070页

作者： Mengyan xie Qing-wen WANG Department of Mathematics Shanghai UniversityShanghai 200444China

We establish necessary and sufficient conditions for the existence of the reducible solution to the quaternion tensor equation A*N C*NB=C via Einstein product using Moore-Penrose inverse,and present an expression of the reducible solution to the equation when it is ***,to have a general solution,we give the solvability conditions for the quaternion tensor equation A1*N C1*MB1+a1*C2*MB2+A2*NC3*MB2=e,which plays a key role in investigating the reducible solution to A*NC*NB=*** expression of such a solution is also presented when the consistency conditions are *** addition,we show a numerical example to illustrate this result.

关键词： Quaternion tensor quaternion tensor equation Einstein product Moore-Penrose inverse general solution reducible solution

Cubic Metric Reduction for Repetitive CAZAC Sequences in Frequency Domain

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China Communications 2021年第12期18卷 196-207页

作者： Yajun Zhao juan Liu Saijin xie Beijing Institute of Technology Beijing 100081China ZTE Corporation Beijing 100029China

To meet the requirements of Occupied Channel Bandwidth(OCB)of unlicensed spectrum,in NR-based Access to Unlicensed Spectrum(NR-U)of 5G New Radio(NR)system,the channels of PRACH and PUCCH have to employ some frequency domain sequence repetition *** repeti-tion schemes cause serious Cubic Metric(CM)prob-lems for these channels,although these two types of channels are composed of Constant Amplitude Zero Auto-correlation(CAZAC)*** the properties of CAZAC sequences,which are used for PRACH and PUCCH(refer to PUCCH format 0 and format 1)in 5G NR system,in this paper,we pro-pose some new schemes of CM reduction for these two channels taking into account the design princi-ples to ensure the sequence performance of the auto-correlation and *** the recom-mended CM reduction schemes are evaluated and the optimized parameters are further provided considering both CM performance and the complexity.

关键词： 5G OFDM cubic metric NR-U oc-cupied channel bandwidth CAZAC zadoff-chu se-quence

Enhanced photogalvanic effect in the two-dimensional MgCl_(2)/ZnBr_(2) vertical heterojunction by inhomogenous tensile stress

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Frontiers of physics 2022年第1期17卷 177-182页

作者： Liyu Qian juan Zhao Yiqun xie Department of Physics Shanghai Normal University100 Guilin RoadShanghai200234China

The photogalvanic effect (PGE) occurring in noncentrosymmetric materials enables the generation of a dc photocurrent at zero bias with a high polarization sensitivity, which makes it very attractive in photodetection. However, the magnitude of the PGE photocurrent is usually small, leading to a low photoresponsivity, and therefore hampers its practical application in photodetection. Here, we propose an approach to largely enhancing the PGE photocurrent by applying an inhomogenous mechanical stretch, based on quantum transport simulations. We model a two-dimensional photodetector consisting of the wide-bandgap MgCl_(2)/ZnBr_(2) vertical van der Waals heterojunction with the noncentrosymmetric C_(3v) symmetry. Polarization-sensitive PGE photocurrent is generated under the vertical illumination of linearly polarized light. By applying inhomogenous mechanical stretch on the lattice, the photocurrent can be largely increased by up to 3 orders of magnitude due to the significantly increased device asymmetry. Our results propose an effective way to enhance the PGE by inhomogenous mechanical strain, showing the potential of the MgCl_(2)/ZnBr_(2) vertical heterojunction in the low-power UV photodetection.

关键词： photogalvanic effect mechanical stretch polarization-sensitive vertical heterojunction ultraviolet photodetection

Modeling simulation and experiment of micro-Doppler signature of precession

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Journal of Systems Engineering and Electronics 2010年第4期21卷 544-549页

作者： Hongwei Gao Lianggui xie Shuliang wen Beijing Institute of Radio Measurement Beijing 100039 R R. China China Aerospace Science & Industry Corporation Beijing 100048 P. R. China

Spatial precession is a special micro-motion of the spinning-directional target, and the micro-Doppler signature of the cone-shaped target with precession is studied. The micro-motion model of precession is built first, and then the micro-Doppler model is developed based on the proposed concept of micro-motion ma- trix, by which the theoretical formula of micro-Doppler signature of precession is derived. In order to further approach to the actual case, the occlusion effect is firstly considered in micro-Doppler, and the simulated result with occlusion effect is well in accordance with the measured result in microwave anechoic chamber, which suggests that the micro-motion model and micro-Doppler model of precession are both valid.

关键词： precession micro-Doppler micro-motion matrix occlusion effect.