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Simulation of Helium Behaviour in Titanium Crystals Using Molecular Dynamics

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Chinese Physics Letters 2006年第7期23卷 1666-1669页

作者：汪俊侯氢孙铁英吴仲成龙兴贵吴兴春罗顺忠 Key Laboratory for Radiation Physics and Technology Institute of Nuclear Science and Technology Sichuan University Chengdu 610064 Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900

The behaviour of helium in Ti crystals at 300 K has been investigated by means of the molecular dynamics. The study is focused on the influences of He-Ti interaction on the aggregation of helium atoms in the substrate. When a Born-Mayer potential is used to describe the He-Ti interaction, the He atoms are unable to cluster with each other due to the weak bridge barrier that cannot trap the helium atoms, Whereas using a He-Ti potential that is constructed by fitting the ab initio pairwise He-Ti potential, the clustering of He atoms can be observed. The results indicate that suitable He-Ti potential plays an important role in the formation of He clusters in metals. Moreover, it is noted that the shape of the formed He cluster is irregular, and the produced defect prefers to congregating on one side of the He cluster rather than spreading symmetrically around it.

关键词： CLUSTERS METALS ALLOY gases

Single-atom catalysts boosted ultrathin film sensors

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Rare Metals 2020年第10期39卷 1110-1112页

作者： Rahul Kumar Mahesh Kumar Department of Electrical Engineering Indian Institute of Technology JodhpurJodhpur 342037India

Nowadays,demand for fast and accurate detection of toxic and flammable gases is increasing for human health safety,industrial process and environmental ***,gas sensor technology has become a requisite in our daily *** nanoscience and nanotechnology propel fabrication of a gas sensor at the miniaturization level for burgeoning Internet of things applications.

关键词： film nanotechnology gases

Stability Diagrams of a Bose-Einstein Condensate in Excited Bloch Bands

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Chinese Physics Letters 2009年第1期26卷 227-230页

作者：梁兆新胡斑比 Department of Physics Centre for Nonlinear Studies and The Beijing-Hong Kong-Singapore Joint Centre for Nonlinear and Complex (Hong Kong) Hong Kong Baptist University Kowloon Tong Hong Kong Department of Physics University of Houston Houston Texas 77204-5005 USA

Landau and dynamical instabilities o/a Bose-Einstein condensate （BEC） in the excited bands of a one-dimensional optical lattice are investigated by the Gross Pitaevskii theory. Our results show that there always exists Landau instability for a BEC in the whole region of excited bands. We also map out the dangerous zones of the dynamical instability. The experimental implications of the stability diagram are discussed.

关键词： OPTICAL LATTICES SUPERFLUID DYNAMICS gases

Controlled Manipulation with a Bose-Einstein Condensates N-Soliton Train under the Influence of Harmonic and Tilted Periodic Potentials

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Chinese Physics Letters 2008年第7期25卷 2370-2373页

作者：宗丰德张解放 Institute of Nonlinear Physics Zhejiang Normal University Jinhua 321004

A model of the perturbed complex Toda chain （PCTC） to describe the dynamics of a Bose-Einstein condensate （BEC） N-soliton train trapped in an applied combined external potential consisting of both a weak harmonic and tilted periodic component is first developed. Using the developed theory, the BEC N-soliton train dynamics is shown to be well approximated by 4N coupled nonlinear differential equations, which describe the fundamental interactions in the system arising from the interplay of amplitude, velocity, centre-of-mass position, and phase. The simplified analytic theory allows for an efficient and convenient method for characterizing the BEC N-soliton train behaviour. It further gives the critical values of the strength of the potential for which one or more localized states can be extracted from a soliton train and demonstrates that the BEC N-soliton train can move selectively from one lattice site to another by simply manipulating the strength of the potential.

关键词： OPTICAL LATTICES TUNNEL ARRAYS WAVE SYSTEMS PROPAGATION STABILITY DYNAMICS VORTEX gases CHAOS

Coherence Measurement of White Light Emission from Femtosecond Laser Propagation in Air

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Chinese Physics Letters 2005年第10期22卷 2608-2610页

作者：金展张杰刘运全李昆远晓辉郝作强郑君鲁欣李玉同王兆华令维军魏志义 Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 State Key Laboratory of Transient Optics Technology Xi'an Institute of Optics and Precision ~lechanics Chinese Academy of Sciences Xi'an 710068

Strong white light emission is observed from femtosecond laser propagation in air. The divergence angle of the white light emission is measured to be about 5mrad. Young＇s double-slits and a Michelson interferometer are used to investigate the coherence. The wavelength components of the white light emission are identified to have a good spatial coherence and a coherence time of about 0.5ps.

关键词： SUPERCONTINUUM GENERATION OPTICAL CHARACTERISTICS CONTINUUM GENERATION PULSES FILAMENTATION DYNAMICS gases BEAM TI

Energetic Protons Emitted from Coulomb Explosion Dynamics of Large-Sized Hydrogen Clusters Driven by an Ultrashort Intense Laser Pulse

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Chinese Physics Letters 2006年第11期23卷 2956-2959页

作者：李洪玉刘建胜王成倪国权李儒新徐至展 State Key Laboratory of High Field Laser Physics Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800

Protons with very high kinetic energy of about lOkeV and the saturation effect of proton energy for laser intensity have been observed in the interaction of an ultrashort intense laser pulse with large-sized hydrogen dusters. Including the cluster-size distribution as well as the laser-intensity distribution on the focus spot, the theoretical calculations based on a simplified Coulomb explosion model have been compared with our experimental measurements, which are in good agreement with each other.

关键词： MOLECULAR CLUSTERS NUCLEAR-DYNAMICS DEUTERIUM CLUSTERS ATOMIC CLUSTERS FIELDS IONIZATION ELECTRON gases

Production of Hyperpolarized 129^Xe Gas Without Nitrogen by Optical Pumping at 133^Cs D2 Line in Flow System

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Chinese Physics Letters 2004年第8期21卷 1501-1503页

作者：周欣孙献平罗军曾锡之刘买利詹明生 StateKeyLaboratoryofMagneticResonanceandAtomicandMolecularPhysics WuhanInstituteofPhysicsandMathematicsChineseAcademyofSciencesWuhan430071

We report production of hyperpolarized 129Xe gas via spin-exchange with optically pumped Cs atoms at the D2 line, achieved at low magnetic field in a flow system and in the absence of nitrogen gas. The nuclear spin polarization of hyperpolarized 129Xe gas is enhanced by a factor of 10000 compared to that without optical pumping under the same condition, which corresponds to polarization of about 2.66%. Due to the high spin polarization, the radiation damping of hyperpolarized 129Xe gas has also been observed in the flow system.

关键词： gases

Self-Trapping of Two Bose-Einstein Condensates with a Coupling Drive

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Chinese Physics Letters 2006年第6期23卷 1387-1390页

作者：邱建国 School of Information and Communication Engineering North University of China Taiyuan 030051

We present an approximate analytical solution to the population imbalance of two-component Bose-Einstein condensate with the coupling drive. The dependence of the time evolution of self-trapping upon the radio frequency wave, the Rabi coupling frequency, the initial atom number and relative phase between two condensates are investigated. The lower radio frequency wave, the same atom number and initial relative phase between condensates are beneficial to observe the self-trapping.

关键词： DYNAMICS INTERFERENCE OSCILLATIONS PHASE gases

On the Spectral Problems for the Discrete Boltzmann Models

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Chinese Physics Letters 2000年第3期17卷 159-161页

作者： Aq Kwang-Hua Chu J.FANG Jing Department of Mechanics and Engineering Science Peking UniversityBeijing 100871

The discrete Boltzmann models are used to study the spectral problems related to the one-dimensional plane wave propagation in monatomic gases which are fundamental in the nonequilibrium statistical *** results show that the 8-velocity model can only describe the propagation of the diffusion mode(entropy wave)in the intermediate Knudsen number *** 4-and 6-velocity models^instead^can describe the propagation of sound inodes quite well,after comparison with the continuum-mechanical results.

关键词： propagation instead gases