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Growth and Characterization of Trumpet-Shaped ZnO Microtube Arrays on Si Substrates

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Chinese Physics Letters 2007年第1期24卷 236-239页

作者：李梦轲王德真史峰丁圣金红 department of Physics Dalian University of Technology Dalian 116020 School of Idhysics and Electronic Technology Liaoning Normal-University Dalian 116029 department of electromechanics Fushun Vocational and Technical College Fushun 113006

Aligned trumpet-shaped zinc oxide microtube arrays have been successfully prepared on silicon （100） substrates via the chemical vapour deposition method with a mixture of ZnO and active carbon powders as reactants. The results show that two types of trumpet-shaped ZnO microtubes can be obtained. A plausible growth mechanism based on the studies of scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, x-ray diffraction （XRD）, and room-temperature photoluminescence spectroscopy is proposed and discussed. The initial metastable zinc-rich ZnOx embryos play a key role in the formation of trumpet-shaped ZnO microtubes. On the different surfaces of metastable zinc-rich ZnOx （x 〈 1）, embryos exhibit different stabilities and resistivities to oxidation; these tiny embryos are gradually extended with different growing rates along the directions of its long axis and circular boundary around its oxide shell. Just this special reason creates the formation of trumpet-shaped microtubes and results in the inerratic and imperfect hexagonshaped cross section that appears. Moreover, the analytical results also show that the as-synthesized ZnO microtube arrays can exhibit better room-temperature photoluminescence behaviour.

关键词： Growth and Characterization Trumpet-Shaped ZnO Microtube Arrays Si Substrates

Temperature Effects of Parabolic Linear Bound Potential and Coulomb Bound Potential Quantum Dot Qubit

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Communications in Theoretical Physics 2009年第10期52卷 601-605页

作者： CHEN Ying-Jie XIAO Jing-Lin College of Physics and Engineering Qufu Normal University Qufu 273165 China department of Physics and electromechanics Inner Mongolia National University Tongliao 028043 China

On the condition of electric-LO phonon strong coupling in a parabolic quantum dot,we obtain theeigenenergy and the eigenfunctions of the ground state and the first-excited state using the variational method ofPekar *** system in a quantum dot may be employed as a two-level quantum *** the electronis in the superposition state of the ground state and the first-excited state,we obtain the time evolution of the *** relations of the probability density of electron on the temperature and the electron-LO-phonon couplingconstant and the relations of the period of oscillation on the temperature,the electron-LO-phonon coupling constant,the Coulomb binding parameter and the confinement length are *** results show that the probability densityof electron oscillates with a period when the electron is in the superposition state of the ground and the first-excitedstate,and show that there are different laws that the probability density of electron and the period of oscillation changewith the temperature and the electron-LO-phonon coupling constant when the temperature is lower or *** is obtained that the period of oscillation decreases with increasing the Coulomb bound potential and increases withincreasing the confinement length not only at lower temperatures but also at higher temperatures.

关键词： quantum dot qubit Coulomb potential temperature effect

Properties of Parabolic Linear Bound Potential and Coulomb Bound Potential Quantum Dot Qubit

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Communications in Theoretical Physics 2008年第2期49卷 311-314页

作者： WANG Zi-Wu LI Wei-Ping YIN Ji-Wen XIAO Jing-Lin department of Physics and Electron Information Engineering Inner Mongolia Chifeng College Chifeng 024000 China department of Physics and electromechanics Inner Mongolia Nationality University Tongliao 028043 China

On the condition of electric-LO phonon strong-coupling in a parabolic quantum dot, we obtain the eigenenergy of the ground-state and the first-excited state, the eigenfunctions of the ground-state and the first-excited state by using variational method of Pekar type. This system in quantum dot may be employed as a two-level quantum system-qubit. When the electron is in the superposition state of the ground- and the first-excited state, we obtain the time evolution of the electron density. The relation of the probability density of electron on the Coulomb binding parameter and the relations of the period of oscillation on the Coulomb binding parameter, the electron-LO-phonon coupling constant and the confinement length are derived.

关键词： quantum dot quantum information qubit decoherece

Properties of a Bound Polaron under a Perpendicular Magnetic Field

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Communications in Theoretical Physics 2007年第5X期48卷 930-934页

作者： LIU Jia XIAO Jing-Lin HUO Shu-Fen CHEN Zi-Yui department of Physics Beijing University of Aeronautics and Astronautics Beijing 100083 China College of Physics and electromechanics Inner Mongolia University for Nationalities Tongliao 028043 China

We investigate the influence of a perpendicular magnetic field on a bound polaron near the interface of a polar-polar semiconductor with Rashba effect. The external magnetic field strongly changes the ground state binding energy of the polaron and the Rashba spin-orbit （SO） interaction originating from the inversion asymmetry in the heterostructure splits the ground state binding energy of the bound polaron. In this paper, we have shown how the ground state binding energy will be with the change of the external magnetic field, the location of a single impurity, the wave vector of the electron and the electron areal density, taking into account the SO coupling. Due to the presence of the phonons, whose energy gives negative contribution to the polaron＇s, the spin-splitting states of the bound polaron are more stable, and we find that in the condition of week magnetic field, the Zeeaman effect can be neglected.

关键词： asymmetric heterostructures spintronics Rashba spin-orbit interaction

DOUBLE LOOP ACTIVE VIBRATION CONTROL OF PNEUMATIC ISOLATOR WITH TWO SEPARATE CHAMBERS

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Chinese Journal of Mechanical Engineering 2006年第4期19卷 610-613页

作者： YANG Qingjun LI Jun WANG Zuwen department of Fluid Control and Automation Harbin Institute of Technology Harbin 150001 China College of electromechanics and Materials Engineering Dalian Mantime University Dalian 116026 China

A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.

关键词： Pneumatic isolator Active vibration control Double-loop control Two separate chambers Mass flow rate compensation (MFRC)

Persistent Currents in the Double Aharonov-Bohm Ring Connected to Electron Reservoirs

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Communications in Theoretical Physics 2007年第3期47卷 573-576页

作者： ZHANG Ying XIAO Jing-Lin department of Mathematics and Physics Hebei Normal University of Science and Technology Qinhuangdao 066004 China College of Physics and electromechanics Inner Mongolia National University Tongliao 028043 China

We study persistent currents in the double Aharonov-Bohm ring connected to two electron reservoirs by quantum waveguide theory. It is found that the persistent currents in the double Aharonov-Bohm ring depend .on the direction of the current flow from one reservoir to another. When the direction of the current flow reverses, tl2e persistent current in each ring of the double Aharonov-Bohm ring changes. If the two rings are of the same size, the persistent currents in the left and the right rings exchange at the reversal of the current flow direction.

关键词： quantum waveguide theory mesoscopic structure persistent currents

Behavior-based Autonomous Navigation and Formation Control of Mobile Robots in Unknown Cluttered Dynamic Environments with Dynamic Target Tracking

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International Journal of Automation and computing 2021年第5期18卷 766-786页

作者： Nacer Hacene Boubekeur Mendil Laboratory of Industrial Technology and Information(LITI) Faculty of TechnologyUniversity of BejaiaBejaia 06000Algeria department of Automatics and electromechanics Faculty of Science and TechnologyUniversity of GhardaiaGhardaia 47000Algeria

While different species in nature have safely solved the problem of navigation in a dynamic environment, this remains a challenging task for researchers around the world. The paper addresses the problem of autonomous navigation in an unknown dynamic environment for a single and a group of three wheeled omnidirectional mobile robots(TWOMRs). The robot has to track a dynamic target while avoiding dynamic obstacles and dynamic walls in an unknown and very dense environment. It adopts a behavior-based controller that consists of four behaviors: "target tracking", "obstacle avoidance", "dynamic wall following" and "avoid robots". The paper considers the problem of kinematic saturation. In addition, it introduces a strategy for predicting the velocity of dynamic obstacles based on two successive measurements of the ultrasonic sensors to calculate the velocity of the obstacle expressed in the sensor frame. Furthermore, the paper proposes a strategy to deal with dynamic walls even when they have U-like or V-like shapes. The approach can also deal with the formation control of a group of robots based on the leader-follower structure and the behavior-based control, where the robots have to get together and maintain a given formation while navigating toward the target, avoiding obstacles and walls in a dynamic environment. The effectiveness of the proposed approaches is demonstrated via simulation.

关键词： Behavior-based autonomous navigation dynamic obstacles and walls dynamic target tracking formation control of multi-robot systems dynamic environment

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Optimal Feedback Control of Nonlinear Variable-Speed Marine Current Turbine Using a Two-Mass Model

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Journal of Marine Science and Application 2020年第1期19卷 83-95页

作者： Rajae Gaamouche Abdelbari Redouane Imad El harraki Bouchra Belhorma Abdennebi El Hasnaoui electromechanics department Mohammadia School of Engineering10000 RabatMorocco electromechanics department National Superior School of Mines10000 RabatMorocco National Centre for Energy Sciences and Nuclear Techniques 10000 RabatMorocco

This paper presents a contribution related to the control of nonlinear variable-speed marine current turbine(MCT)without pitch operating below the rated marine current *** that the operation of the MCT can be divided into several operating zones on the basis of the marine current speed,the system control objectives are different for each *** deal with this issue,we develop a new control approach based on a linear quadratic regulator with variable generator *** proposed approach enables the optimization of the rotational speed of the turbine,which maximizes the power extracted by the MCT and minimizes the transient loads on the *** novelty of our study is the use of a real profile of marine current speed from the northern coasts of *** simulation results obtained using MATLAB Simulink indicate the effectiveness and robustness of the proposed control approach on the electrical and mechanical parameters with the variations of marine current speed.

关键词： Marine current turbine Two-mass model Tip speed ratio Linearization Optimal control Linear quadratic regulator(LQR)

A Novel Matlab-Based Underwater Acoustic Channel Simulator

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通讯和计算机（中英文版） 2013年第8期10卷 1131-1138页

作者： Zarnescu George department of Electrical Engineering and Telecommunications Faculty of Electromechanics Maritime University of ConstantaConstanta 900663 Romania