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Structural Stabilities of Ordered Nb4 Clusters on the Cu（111） and Cu（100） Surfaces

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Chinese Physics Letters 2007年第1期24卷 172-175页

作者：王晓春朱梓忠 Department of Physics and Institute of Theoretical Physics and Astrophysics Xiamen University Xiamen 361005

Based on first-principles calculations, we show that very high-density periodic arrays of Nb4 clusters with both the tetrahedron and quadrangle configurations can be stably absorbed on the Cu（111） and Cu（100） surfaces, with the quadrangle configurations more stable than the tetrahedron ones. The strong covalent bonding between atoms within the Nb4 clusters contributes to the stability of Nb4 adsorptions on the Cu surfaces. The energy barriers for the tetrahedron to the quadrangle-Nb4 on Cu（111） and （100） are around 1.21 eV and 0.94 eV/cluster, respectively. The stable adsorption of high-density Nb4 on these surfaces should have important applications.

关键词： GROWTH arrays tetrahedrons Structural stability Adsorption Energy barrier Clusters Quad Pill arrays

Simulation of Space Charge Effect in Field Emission from a Nanowire

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Chinese Physics Letters 2005年第3期22卷 648-650页

作者：裴铁张耿民 KeyLaboratoryforthePhysicsandChemistryofNanodevicesandDepartmentofElectronics SchoolofElectronicsEngineeringandComputerSciencePekingUniversityBeijing100871

At present, field emission from nanowires (NWs) is under intenseinvestigation. In experiments, the dependence of field emission current from an NW on appliedvoltage (I-V behavior) often deviates from the Fowler-Nordheim (FN) theory. We simulate the role ofthe space charge effect in the I-V behaviour of an NW. We determine the threshold electric field, atwhich the space charge effect starts to manifest itself, under different NW work functions. Oursimulation result has confirmed that space charge effect is one of the possible factors responsiblefor the nonlinearity of the FN plots of an NW at high fields. Furthermore, our calculation revealsthat the threshold field is related to the NW work function in an almost linear manner.

关键词： CARBON NANOTUBES arrays

Real-time reconfigurable metasurfaces enabling agile terahertz wave front manipulation

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Light(Science & Applications) 2023年第12期12卷 2551-2553页

作者： Huixian Zhou Cheng Zhang School of Optical and Electronic Information&Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Real-time controlled programmable metasurfaces,having an array-of-subarrays architecture under the control of one-bit digital coding sequence,are demonstrated for rapid and precise multifunctional Terahertz wave front... 详细信息

关键词： reconfigurable wave arrays

Field Emission Enhancement of Carbon Nanotubes by Surface Modification

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Chinese Physics Letters 2007年第1期24卷 233-235页

作者：勇振中巩金龙王震霞朱志远胡建刚潘强岩 Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 Graduate School of the Chinese Academy of Sciences Beijing 100049

By employing a multi-walled carbon nanotube （MWCNT） film as the substrate, we obtain Fe tipped carbon nanorods or carbon nanoparticles grown on the outer walls of MWCNTs by combining sputtering deposition of Fe films and rf plasma enhanced chemical vapour deposition at high temperature. Scanning electron microscopy and high-resolution transmission electron microscopy are used to examine the structure of carbon nanorods and carbon nanoparticles. In addition, the formation mechanism is discussed briefly. The electron field emission tests indicate that the turn-on field （at 10μA/cm^2） of the treated MWCNT films decreases from 2.4 V/μm to O. 79 V/μm and the field emission current is relatively stable. The enhanced field enhancement factor, increasing emission densities coming from the grown nanorods and nanoparticles, and H terminated by H plasma a11 are responsible for the enhancement of the field enhancement factor.

关键词： CHEMICAL-VAPOR-DEPOSITION PLASMA FILMS NANOFIBERS DISPLAY GROWTH arrays Multi-Walled Nanotube Carbon Nanotubes Nanorods Plasma enhanced chemical vapor deposition carbon nanoparticles arrays Nanofibres Surface treatment Plasmas Films exterior walls enhancement factor AT-Rich Interactive Domain-Containing Protein 1A

Fabrication of GaN Nanorods in a Large Scale on Si（111）Substrate by Ammoniating Technique

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Chinese Physics Letters 2006年第11期23卷 3052-3054页

作者：艾玉杰薛成山孙莉莉孙传伟庄惠照王福学陈金华李红 Institute of Semiconductors Shandong Normal University Jinan 250014 School of Information Science and Engineering Jinan University Jinan 250022

GaN nanorods in a large scale have been synthesized on Si （111） substrates by ammoniating Ga2O3/Mg films under flowing ammonia atmosphere at the temperature of 1000℃ for 15 min. The as-synthesized GaN nanorods are characterized by scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and highresolution transmission electron microscopy. The results demonstrate that these straight nanorods are hexagonal wurtzite GaN single crystals in diameters ranging from 200 nm to 600 nm.

关键词： GALLIUM NITRIDE arrays

Monte Carlo Simulation of Magnetization Behaviour of Co Nanowires

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Chinese Physics Letters 2006年第1期23卷 200-203页

作者：钟克华黄志高冯倩蒋丽钦杨艳敏陈志高 Department of Physics Fujian Normal University Fuzhou 350007

Based on the Monte Carlo method, we simulate the magnetization curves with various magnetic field orientations for various single Co nanowires at room temperature. The simulated switching field as a function of angle between the field and the wire axis is consistent well with the experimental data. Correspondingly, the coercivity as a function of angle θ is presented, which together with the switching field plays an important role on explaining the magnetic reversal mechanism. It is found that the angular dependence of coercivity depends on the diameter of nanowires, and the coercivity and switching field versus θ deviate markedly from the prediction from the classical uniform rotation mode in the chain-of-sphere model. Furthermore, the magnetic reversal configurations display that magnetization reversal in the wires with small diameters is a nucleation-propagation process, and it is similar to the curling spread process in the larger wires.

关键词： MAGNETORESISTANCE REVERSAL arrays NICKEL NI ANISOTROPY PARTICLES FE

Experimental Investigation on a Fibre-Optic Hydrophone with a Cylindrical Helmholtz Resonator

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Chinese Physics Letters 2008年第5期25卷 1606-1608页

作者：王泽锋胡永明孟洲倪明 College of Photoelectric Science and Engineering National University of Defense Technology Changsha 410073

A novel mechanical anti-aliasing filtering fibre-optic hydrophone with a cylindrical Helmholtz resonator is con- structed and tested. The experimental results show that the hydrophone has a function of low-pass filtering. The low frequency acoustic sensitivity is about -160 dB （1 rad/#Pa）, and the response curve has a resonance deter- mined by the Helmholtz resonator. Theoretical and experimental results both show that the resonant frequency moves towards high frequency with the increasing orifice diameters. The sensitivity attenuation of high frequency is larger than lOdB. This new fibre-optic hydrophone is a prototype device for a class of sensors used to eliminate the aliasing in future sonar systems.

关键词： arrays

Vortex Pinning due to Dynamic Spin-Vortex Interaction in a Superconductor//Ferromagnet Multilayer

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Chinese Physics Letters 2009年第1期26卷 310-313页

作者：吴鸿业邹涛成昭华孙阳 State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190

We investigate the mutual interaction between superconductivity and ferromagnetism in a Nb/Ni81 Ee19 multilayer by ac susceptibility measurements. Compared with a pure superconducting Nb film, the critical current density of the multilayer is apparently enhanced in a low magnetic field region but remains nearly the same in high magnetic fields, which indicates that a continuous ferromagnetic layer with in-plane magnetization can produce strong vortex pinning in a low field region. We interpret this unusual vortex-pinning phenomenon as a consequence of dynamic spin vortex interaction which induces a spin rotation following vortex movement. In addition, we propose that this dynamic interaction could be used for spin manipulation via a superconductor.

关键词： MAGNETIC DOTS arrays

Evolution of Matter Wave Interference of Bose-Condensed Gas in a 1D Optical Lattice

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Chinese Physics Letters 2007年第9期24卷 2493-2496页

作者：徐志君张冬梅 College of Science Zhejiang University of Technology Hangzhou 310032 The State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071

For a Bose-condensed gas in a combined potential consisting of an axially-symmetric harmonic magnetic trap and one-dimensional （1D） optical lattice, using the mean-field Gross-Pitaevskii （G-P） equation and the propagator method, we obtain the analytical result of the order parameter for matter wave interference at any time. The evolution of the interference pattern under a variation of the relative phase △Ф between successive subcondensates trapped on an optical lattices is also studied. For △Ф=π, the interference pattern is symmetric with two sharp peaks, which are symmetrically located on a straight line on both sides of a vacant central peak and moving apart from each other. This work is in agreement with available experimental results.

关键词： EINSTEIN CONDENSATE SUPERFLUID arrays TRAP