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On the Scaled Fractional Fourier Transformation Operator

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Chinese Physics Letters 2008年第2期25卷 513-516页

作者：范洪义胡利云 Department of Physics Shanghai Jiao Tong University Shanghai 200030

Based on our previous study [Chin. Phys. Lett. 24 （2007） 2238] in which the Fresnel operator corresponding to classical Fresnel transform was introduced, we derive the fractional Fourier transformation operator, and... 详细信息

关键词： pulsars x-ray spectra relativity and gravitation redshift

Single-Photon Emission from a Single InAs Quantum Dot

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Chinese Physics Letters 2008年第2期25卷 501-504页

作者：窦秀明孙宝权黄杜松倪海桥牛智川 SKLSM Institute of Semiconductors Chinese Academy of Sciences PO Box 912 Beijing 100083

Excitation power-dependent micro-photoluminescence spectra and photon-correlation measurement are used to study the optical properties and photon statistics of single InAs quantum dots. Exciton and biexciton emissions, whose photoluminescence intensities have linear and quadratic excitation power dependences, respectively, are identified. Under pulsed laser excitation, the zero time delay peak of second order correlation function corresponding to exciton emission is well suppressed, which is a clear evidence of single photon emission.

关键词： pulsars x-ray spectra relativity and gravitation redshift

A Measure for Isotropy-Equilibrium Degree of a Multi-Particle System

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Chinese Physics Letters 2008年第2期25卷 447-450页

作者：刘智春李润泽许明梅刘连寿 College of Physical Science and Technology Huazhong Normal University Wuhan 430079

Aiming at using sphericity as a tool to study the isotropy-equilibrium property of a multi-particle system, in particular the hadronic final state IFS produced in instanton-induced DIS events, we discuss in detail the dependence of sphericity on multiplicity and the multiplicity distribution, as well as on the isotropy degree of the system. A rotational symmetric model with a fluctuating isotropy-degree is constructed, which can fit the mean and width of sphericity of the Monte Carlo IFS-results simultaneously. The IFS from the Monte Carlo simulation is found to be not ideally isotropic but has a probability of 4.7% to be isotropic within error of 5%. The results provide us a description of how far the IFS departs from equilibrium. The method developed is applicable to any Monte Carlo generated multi-particle system, for which the isotropy-equilibrium property is significant.

关键词： pulsars x-ray spectra relativity and gravitation redshift

Design of Broadband Single Fundamental Mode Hollow Core Bragg Fibre

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Chinese Physics Letters 2008年第2期25卷 570-573页

作者：林晨曦张巍黄翊东彭江得 Department of Electronics Engineering Tsinghua University Beijing 100084

The condition of the single fundamental mode （HE11） transmission in hollow core Bragg fibres is investigated theoretically by the transfer matrix method. The influences of core size and cladding parameters on the single HE11 mode bandwidth are analysed, showing that the maximal bandwidth is more sensitive to the core size than the cladding. The numerical results show that sufficiently broad bandwidth of single HE11 mode transmission can be achieved by proper fibre design. A simple and fast method based on improved hollow metal waveguide model is proposed to optimize fibre structure parameters for the maximal single HE11 mode bandwidth.

关键词： pulsars x-ray spectra relativity and gravitation redshift

B→K Transition Form Factor with Tensor Current within the kT Factorization Approach

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Chinese Physics Letters 2008年第2期25卷 436-439页

作者：曾代敏吴兴刚方祯云 Department of Physics Chongqing University Chongqing 400044

We apply the kT factorization approach to deal with the B→K transition form factor with tensor current in the large recoil regions. Main uncertainties for the estimation are discussed and we obtain FT^B→K （0） = 0.25±0.01±0.02, where the first error is caused by the uncertainties from the pionic wavefunctions and the second is from that of the B-meson wavefunctions. This result is consistent with the light-cone sum rule results obtained in the literature.

关键词： pulsars x-ray spectra relativity and gravitation redshift

An Integrative Biosensor Based on Contra-Directional Coupling Two-dimensional Photonic Crystal Waveguides

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Chinese Physics Letters 2008年第1期25卷 141-143页

作者：毛晓宇姚荻笔赵凌云黄翊东张巍彭江得 State Key Lab of Integrated Optoelectronics Department of Electronics Engineering Tsinghua University Beijing 100084

We propose an integrative biochemical sensor utilizing the dip in the transmission spectrum of a normal singleline defect photonic crystal （PC） waveguide, which has a eontra-directional coupling with another PC waveguide. When the air holes in the PC slab are filled with a liquid analyte with different refractive indices, the dip has a wavelength shift. By detecting the output power variation at a certain fixed wavelength, a sensitivity of 1.2 × 10^-4 is feasible. This structure is easy for integration due to its plane waveguide structure and omissible pump source. In addition, high signal to noise ratio can be expected because signal transmits via a normal single-line defect PC waveguide instead of the PC hole area or analyte.

关键词： pulsars x-ray spectra relativity and gravitation redshift

Low-Frequency Relaxation Oscillations in Capacitive Discharge Processes

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Chinese Physics Letters 2008年第2期25卷 707-710页

作者：周筑文 M. A. LIEBERMAN Sungjin KIM 吉世印邓明森孙光宇 Department of Physics Guizhou Educational College Guiyang 550003 Department of Electrical Engineering and Computer Sciences-1770 University of California Berkeley CA 94720 USA

Low-frequency （2.72-3.70 Hz） relaxation oscillations at 100 mTorr at higher absorbed power were observed from time-varying optical emission of the main discharge chamber and the periphery. We interpret the low frequency oscillations using an electromagnetic model of the slot impedance with parallel connection variational peripheral capacitance, coupled to a circuit analysis of the system including the matching network. The model results are in general agreement with the experimental observations, and indicate a variety of behaviours dependent on the matching conditions.

关键词： pulsars x-ray spectra relativity and gravitation redshift

Asymptotic Analysis of Vertical Branch-Cut Integral of Shear Waves in a Fluid-Filled Borehole Utilizing the Steepest-Descent Method

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Chinese Physics Letters 2008年第2期25卷 578-581页

作者：姚桂锦宋若龙王克协 College of Communication Engineering Jilin University Changchun 130012 School of Physics Jilin University Changchun 130021

We obtain an asymptotic solution to the vertical branch-cut integral of shear waves excited by an impulsive pressure point source in a fluid-filled borehole, by taking the effect of the infinite singularity of the Hankel functions related to shear waves in the integrand at the shear branch point into account and using the method of steepest-descent to expand the vertical branch-cut integral of shear waves. It is theoretically proven that the saddle point of the integrand is located at ks-i/z, where ks and z are the shear branch point and the offset. The continuous and smooth amplitude spectra and the resonant peaks of shear waves are numerically calculated from the asymptotic solution. These asymptotic results are generally in agreement with the numerical integral results. It is also found by the comparison and analysis of two results that the resonant factor and the effect of the normal and leaking mode poles around the shear branch point lead to the two-peak characteristics of the amplitude spectra of shear waves in the resonant peak zones from the numerical integral calculations.

关键词： pulsars x-ray spectra relativity and gravitation redshift

Classical Study of Transfer and Ionization in A^2＋＋He Collisions

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Chinese Physics Letters 2008年第2期25卷 479-481页

作者：丁宝卫陈熙萌付宏斌刘兆远 School of Nuclear Science and Technology Lanzhou University Lanzhou 730000

A simple model for the direct ionization and transfer ionization probabilities in A^2＋＋He collisions in a wide projectile energy range is proposed based on the Bohr-Lindhard model and the classical statistical model... 详细信息

关键词： pulsars x-ray spectra relativity and gravitation redshift