Table of contents

20 January 1995, Volume 4 Issue 1 Previous issue    Next issue

ATOMIC AND MOLECULAR PHYSICS

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DISTORTED WAVE CORRECTION OF CENTRIFUGAL SUDDEN WAVE PACKET APPROXIMATION REN TING-QI (任廷琦), LI DAI-QING (李岱青), LIU SHENG-DIAN (柳盛典), ZHANG QING-GANG (张庆刚) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  1-5.  DOI: 10.1088/1004-423X/4/1/001 Abstract ( 1376 )   PDF (122KB) ( 419 )   A distorted wave procedure is employed to correct the centrifugal sudden wave packet approximation, and the accurate results compared with the standard close coupling method for m-dependent integral cross sections for short- and long- range Ar+N2 potentials at E=O.O258eV are obtained only by using the second-order corrections to the CSWP wave function.

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STUDY OF THE DOPPLER-FREE OPTICAL-OPTICAL TRIPLE-RESONANCE(DF-OOTR) SPECTROSCOPY AND ITS LINESHAPES PAN YONG-LE (潘永乐), XIA HUI-RONG (夏慧荣), YE CUN-YUN (叶存云), DING LIANG-EN (丁良恩), MA LONG-SHENG (马龙生), WANG ZU-GENG (王祖赓) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  6-15.  DOI: 10.1088/1004-423X/4/1/002 Abstract ( 1213 )   PDF (313KB) ( 430 )   The Doppler-free optical-optical triple-resonance(DF-OOTR) spectroscopy and its line-shapes have been studied in detail theoretically and experimentally. The line center, linewidth and lineshape of an isolated DF-OOTR spectra component have been derived by using density matrix motion equation describing the interaction of a three-level system with three optical fields. The variations of the lineshape symmetry, the relative position and the strength of the Doppler-free Lorentzian dip to its background are comparable to the experimental traces varying with the relative intensities of the two mutual-saturating probe laser beams, as well as with the detuning of the first pumping laser from the intermediate level. The DF-OOTR technique shows a distinguished advantage especially in the labeling of the transitions and in the determination of absolute position of the upper level affected by perturbation shift, as these happened often in the dense molecular highly excited states.

CLASSICAL AREAS OF PHENOMENOLOGY

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THEORETICAL STUDY OF SELF-STARTING MODE-LOCKED ALL-FIBER LASERS SUN JUN-QIANG (孙军强), HUANG DE-XIU (黄德修), LI ZAI-GUANG (李再光) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  16-23.  DOI: 10.1088/1004-423X/4/1/003 Abstract ( 1280 )   PDF (202KB) ( 528 )   In this paper, the self-startlng mode-locking characteristics of all-fiber lasers are in-vestigated theoretically. The mechanism of self-starting mode-locking is analyzed and the experimental phenomena are explained successfully by introducing effective energy gain. The modulation characteristics of all-fiber lasers and the effect of gain saturation on modulation characteristics are discussed by analyzing the transmissivity of Er-doped fiber loop. Finally, the dynamic processes of all-fiber self-starting mode-locked lasers are simulated numerically.

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SPECTRA, ENERGY LEVELS AND UP-CONVERSION EFFECT OF ERBIUM IONS IN LiNbO3 CRYSTALS RUAN YONG-FENG (阮永丰), LI BAO-LING (李宝凌), LI WEN-RUN (李文润), WAN LIANG-FENG (万良风) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  24-32.  DOI: 10.1088/1004-423X/4/1/004 Abstract ( 1124 )   PDF (237KB) ( 418 )   The Optical properties and spectral data of erbium-doped Lithium Niobate crystals,including absorption spectrum, emission spectrum, luminescence lifetime and up-conversion effects are reported in this paper. The energy level scheme, Stark splitting under crystal field and up-conversion mechanism are discussed in detail. The possible applications of this material in waveguide optics and opto-electronics are also prospected.

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A STUDY OF THE PHYSICAL PROPERTIES OF ZEEMAN ABSORPTION FARADAY ANOMALOUS DISPERSION OPTICAL FILTER DUAN MING-HAO (段明浩), LI YI-MIN (李义民), TANG JUN-XIONG (汤俊雄), WANG QING-JI (王庆吉) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  33-38.  DOI: 10.1088/1004-423X/4/1/005 Abstract ( 1304 )   PDF (149KB) ( 454 )   This paper reports what is to our knowledge the first demonstration of Zeeman absorption Faraday anomalous dispersion optical filter (hereafter abbreviated to FADOF/Zeeman). The mutual relations among passband, tuning capability, cell temperature and magnetic field of FADOF/Zeeman have been studied theoretically and experimentally. The results showed that the single passband of FADOF/Zeeman was about 1 GHz, which is 3 times less than the passband of FADOF. The tuning capability was about 1 GHz/0.01 T.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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THE ELECTRON CYCLOTRON RESONANCE HEATING EXPERIMENTS ON HL-1 TOKAMAK XU YAO-CONG (徐耀聪), XUE SI-WEN (薛思文), LIU YONG (刘永), XU DE-MING (徐德明), GUO GAN-CHENG (郭干城), DING XUAN-TONG (丁玄同), CHEN MIAO-WEN (陈妙文), YU LI-MU (余利木), JIANG XIU-FANG (蒋秀芳), LI XIAO-DONG (李晓东), DENG XI-WEN (邓希文), WANG EN-YAO (王恩耀), YANG SI-ZE (杨思泽), YAO XIN-ZI (姚鑫兹), V.V.ROZHDESTVENSK, B.V.SHISHKIN, V.I.MALYGIN Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  39-46.  DOI: 10.1088/1004-423X/4/1/006 Abstract ( 1262 )   PDF (213KB) ( 459 )   The electron cyclotron resonance heating (ECRH) experiments on HL-1 tokamak with 300kW of power generated by a gyrotron are described. With ECE diagnostics, a 30% increase of electron temperature has been obtained. The following phenomena have been observed with various diagnostics during ECRH: increase of radiation intensity of soft X-ray; amplitude change and period elongation of sawtooth oscillation; MHD instability suppression; increase of H$\alpha$ spectral fine intensity and ionized impurity radiation from edge plasma; increase of the temperature and density of edge plasma. Although the total plasma energy content increases, the energy confinement time is decreased. Initial results of low voltage start-up experiments have also been obtained.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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STUDY ON THE STABILITY OF GaAs/AlGaAs SUPERLATTICE STRUCTURE XU XIAN-GANG (徐现刚), HUANG BAI-BIAO (黄柏标), REN HONG-WEN (任红文), JIANG MIN-HUA (蒋民华) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  47-53.  DOI: 10.1088/1004-423X/4/1/007 Abstract ( 1336 )   PDF (207KB) ( 449 )   This paper reports the stability of GaAs/AlGaAs superlattice structures after theorem annealing, Zn diffusion and MeV Si+ ion implantation. The MeV Si+ ion implantation induced damage in GaAs/AlGaAs superlattices, its annealing properties, and the effects on superlattice structure stability are reported as well. Thermal annealing at 650℃ for 30min has little effect on superlattice structure. Zn diffusion may induce superlattice layer disordering. And annealing at 650℃ for 30min can eliminate damage caused by 2.3MeV,1.5×1015 cm-2 Si+ ion implantation, which cannot induce superlattice layer disordering.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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A TWO-STATE MODEL FOR NON-EXPONENTIAL RELAXATION IN CONDENSED MATTER WEN CHAO (文超) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  54-61.  DOI: 10.1088/1004-423X/4/1/008 Abstract ( 1347 )   PDF (232KB) ( 355 )   A two-state model is presented for polarization relaxation in condensed matter. The dynamics of relaxation is treated with quantum transition theory. The physical meaning of the so-called time-dependent transition rate is clarified. The new model not only gives the fractional exponential and power-law relaxation functions naturally, but also indicates that the universality of the relaxation law results from the scaling behavior of low-frequency effective spectrum.

CROSS DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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CALCULATION OF THE HEAT OF FORMATION OF TERNARY COMPOUNDS: P-Ga-As, N-Ga-As, N-Ga-P WU XIAO-SHAN (吴小山), YAN XIAO-HUA (鄢晓华), MA BEN-KUN (马本堃), LIN ZHEN-JIN (林振金), YANG XI-ZHEN (杨锡震) Acta Physica Sinica (Overseas Edition), 1995, 4 (1):  62-70.  DOI: 10.1088/1004-423X/4/1/009 Abstract ( 1020 )   PDF (261KB) ( 358 )   Miedema method, which was proposed to calculate the heat of formation of binary alloy system, is extended for calculating the heat of formation of ternary system by using the Toop's model. The hypothetical metallic allotropes correspounding to the properties of nonmetallic elements are introduced. In our calculation, the structure-dependent energy contributions have not been taken into account. The heat of formation of GaAs1-x Px, GaAs1-xNx, and GaP1-xNx are obtained by projecting the heat of formation of ternary systems, P-Ga-As, N-Ga-As, and N-Ga-P onto the plane of the concentration of Ga, c2 = 0.5, respectively. The possibility of existence of ordered ternary compound was predicted. The dependence of direct band gap, E$\varGamma$, or indirect one, EX, for GaP1-xNx and GaAs1-xNx, on x, the concentration of N, is obtained by using the dielectric theory of electronegativity.