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2000年, 第9卷, 第4期　刊出日期：2000-04-15 上一期    下一期

GENERAL

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THE RELATIVISTIC COVARIANCE OF ONNES EQUATION 刘泽文, 朱镇龙, 孟祥君 2000 (4):  241-243.  doi: 10.1088/1009-1963/9/4/001 摘要 ( 873 )   PDF(171KB) ( 332 )   On the assumption that Onnes equations meet the requirements of the relativistic covariance, virial coefficients as functions of temperature are derived by using the transformations between thermodynamic variables provided by the vector theory of relativistic thermodynamics, and result in agreement with those obtained from cluster expansions in statistics. This breaks, to some extent, the traditional ideas that the thermodynamic theory is not able to derive equations of state at all and presents a possibly simple and new way of finding theoretically the equation of state. 相关文章 | 计量指标

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USING OPTIMAL FEEDBACK CONTROL FOR CHAOS TARGETING 彭召旺, 钟廷修 2000 (4):  244-249.  doi: 10.1088/1009-1963/9/4/002 摘要 ( 1033 )   PDF(146KB) ( 377 )   Since the conventional open-loop optimal targeting of chaos is very sensitive to noise, a close-loop optimal targeting method is proposed to improve the targeting performance under noise. The present optimal targeting model takes into consideration both precision and speed of the targeting procedure. The parameters, rather than the output, of the targeting controller, are directly optimized to obtain optimal chaos targeting. Analysis regarding the mechanism is given from physics aspect and numerical experiment on the Hénon map is carried out to compare the targeting performance under noise between the close-loop and the open-loop methods. 相关文章 | 计量指标

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RESONANT INTERACTION BETWEEN A PAUL-TRAPPED ION AND A STANDING WAVE LASER 冯芒, 海文华, 朱熙文, 高克林, 施磊 2000 (4):  250-258.  doi: 10.1088/1009-1963/9/4/003 摘要 ( 1029 )   PDF(321KB) ( 370 )   An ultracold two-level ion experiencing the standing wave of a resonant laser in a Paul trap is investigated in the Lamb-Dicke limit and weak excitation regime, with full consideration of the time-dependence of the trapping potential. The analytical forms of the wave functions of the system can be described with our approach, and the time evolution of the pseudo-energy of the system as well as the squeezing property of the quadrature components is studied in comparison with the treatment of harmonic oscillator model. 相关文章 | 计量指标

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QUANTUM LANGEVIN THEORY OF WHISPERING-GALLERY-MODE MICROSPHERE LASER 柴金华, 路轶群, 梁培 2000 (4):  259-273.  doi: 10.1088/1009-1963/9/4/004 摘要 ( 1358 )   PDF(324KB) ( 447 )   A quantum Langevin theory of whispering-gallery-mode microsphere laser theory is developed. The linear and nonlinear analysis are made for laser operation below and above the threshold. In these analysis, corresponding to the specific property of microsphere, the effect of inversion fluctuation is treated. The coherence functions of laser field are calculated, and the intensity, the amplitude fluctuation and the linewidth of the field are obtained, which are connected with the enhancement factor of whispering-gallery-mode microsphere. It is shown that the strong couple and strong pumping are useful for the amplification of intensity and the decrease of linewidth below the threshold. It is also shown that, for the laser action above threshold, the variances of photon number and the linewidth of internal field are related to the enhancement factor and the square of the enhancement factor, respectively. 相关文章 | 计量指标

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DISPERSION RELATION OF A MAGNETIZED PLASMA-FILLED BACKWARD WAVE OSCILLATOR 高宏, 刘盛纲 2000 (4):  274-278.  doi: 10.1088/1009-1963/9/4/005 摘要 ( 1036 )   PDF(109KB) ( 518 )   A linear theory and a more general dispersion relation of electromagnetic radiation from a magnetized plasma-filled backward wave oscillator with sinusoidally corrugated slow-wave structure driven by a solid intense relativistic electron beam have been given. The comparisons show good agreement with the previous works when B0→∞ and ωb=0 from this dispersion relation. 相关文章 | 计量指标

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THE EFFECT OF MESH ANODE ON CATHODIC ARC IN FOCUSING MAGNETIC FIELD 张涛, 侯君达, 汤宝寅, T. K. Kwok, 曾照明, I. G. Brown, Paul K. Chu 2000 (4):  279-283.  doi: 10.1088/1009-1963/9/4/006 摘要 ( 1136 )   PDF(129KB) ( 450 )   The performance and characteristics of a cathodic arc deposition apparatus consisting of a titanium cathode, an anode with and without a tungsten mesh, and a coil producing a focusing magnetic field between the anode and cathode are investigated. The arc voltage Va is measured with a fixed arc current. The relationship between Va and the magnetic field B with and without a mesh is obtained. In addition, the relationship between the arc current Ia and Vc, the voltage to which the artificial transmission line was charged, is measured with and without the mesh to determine the minimum ignition voltage for the arc. The arc resistance increases with the focusing magnetic strength B and decreases when using the mesh. Our results indicate that the high transparency and large area of the mesh allows a high plasma flux to penetrate the anode from the cathodic arc. The mesh also stabilizes the cathodic arc and gives better performance when used in concert with a focusing magnetic field. 相关文章 | 计量指标

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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CHARACTERIZATION OF POLYCRYSTALLINE GRADIENT THIN FILM BY X-RAY DIFFRACTION METHOD 李彬, 陶琨, 刘兴涛, 苗伟, 冯涛, 杨宁, 柳百新 2000 (4):  284-289.  doi: 10.1088/1009-1963/9/4/007 摘要 ( 1142 )   PDF(239KB) ( 333 )   A direct method is proposed to quantitatively characterize the structural depth profiles emerged in the polycrystalline thin films based on the information obtained by X-ray diffraction (XRD) with various incident angles and treated by a numerical procedure known as the constrained linear inversion. It should be noted that the proposed method was neither sensitive to the random noise appearing in experiment nor to the error originated from the measured thickness of the specimen. To testify the validity of the method, XRD measurements were carried out on a specially designed Pd/Ag bilayer sample, which was annealed at 490℃ for 20 min, and the depth profiles were accordingly calculated through resolving the obtained XRD patterns. The elemental concentration depth profile of the Pd/Ag bilayer sample was in turn calculated from the resolved patterns, which was in good agreement with those obtained by Auger electron analysis on the annealed sample. 相关文章 | 计量指标

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ELECTRON PARAMAGNETIC RESONANCE STUDIES OF DIMENSIONALITY OF POLYANILINE FILMS 蒋志洁, 莫党 2000 (4):  290-293.  doi: 10.1088/1009-1963/9/4/008 摘要 ( 1044 )   PDF(98KB) ( 368 )   The line shape analysis of electron paramagnetic resonance (EPR) spectra for low-dimensional solids are calculated. A comparison is carried out between the experimental EPR results of polyaniline samples and theoretical calculation. The dimension evolution of the samples from nonconducting to conducting states is obtained. It is found that the dimensional properties determined by EPR are in good accordance with those obtained using previous ellipsometric methods. 相关文章 | 计量指标

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AXISYMMETRIC ELASTICITY PROBLEM OF CUBIC QUASICRYSTAL 周旺民, 范天佑 2000 (4):  294-303.  doi: 10.1088/1009-1963/9/4/009 摘要 ( 1033 )   PDF(121KB) ( 533 )   A method for analyzing the elasticity problem of cubic quasicrystal is developed. The axisymmetric elasticity problem of cubic quasicrystal is reduced to a single higher-order partial differential equation by introducing a displacement function. As an example, the solutions of elastic field of cubic quasicrystal with a penny-shaped crack are obtained, and the stress intensity factor and strain energy release rate are determined. 相关文章 | 计量指标

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MAGNETIC PROPERTIES OF BALL MILLED FexCu1-x (x=0.4, 0.5) ALLOY 李玉芝, 林磊, 王汪陈, 熊曹水, 沈保根 2000 (4):  304-308.  doi: 10.1088/1009-1963/9/4/010 摘要 ( 1210 )   PDF(143KB) ( 408 )   The samples Fe0.4Cu0.6 and Fe0.5Cu0.5 ball milled for 50 h are investigated by X-ray diffraction, M?ssbauer spectra, as well as magnetic measurement. The experiments show that the structure of the samples is fcc, with lattice constant 0.361 nm and there are fcc Fe-rich phase and fcc Cu-rich phase in the samples. Most of Fe atoms (91%) are in the fcc Fe-rich phase, which is a ferromagnetic phase. The M-H curve at 1.5 K shows the saturation magnetization of the samples are 80.5 emu/g and 101.6 emu/g for Fe0.4Cu0.6 and Fe0.5Cu0.5 respectively. The average magnetic moment of Fe atoms is deduced to be 2.40 μB . Compared with theoretical predication, the Fe atoms in the fcc phase are in high spin state. 相关文章 | 计量指标

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MICROSTRUCTURE OF SiOx:H FILMS PREPARED BY PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION 马智训, 廖显伯, 孔光临, 褚君浩 2000 (4):  309-312.  doi: 10.1088/1009-1963/9/4/011 摘要 ( 969 )   PDF(117KB) ( 504 )   The micro-Raman spectroscopy and infrared (IR) spectroscopy have been performed for the study of the microstructure of amorphous hydrogenated oxidized silicon (a-SiOx:H) films prepared by Plasma Enhanced Chemical Vapor Deposition technique. It is found that a-SiOx:H consists of two phases: an amorphous silicon-rich phase and an oxygen-rich phase mainly comprised of HSi-SiO2 and HSi-O3. The Raman scattering results exhibit that the frequency of TO-like mode of amorphous silicon red-shifts with decreasing size of silicon-rich region. This is related to the quantum confinement effects, similar to the nanocrystalline silicon. 相关文章 | 计量指标