Table of contents

20 January 1993, Volume 2 Issue 1 Previous issue    Next issue

ATOMIC AND MOLECULAR PHYSICS

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STUDY OF FARADAY ANOMALOUS DISPERSION SPECTRA OF THE HYPERFINE STRUCTURE OF Rb D2 LINES PENG YU-FENG (彭玉峰), TANG JUN-XIONG (汤俊雄), WANG QING-JI (王庆吉) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  1-8.  DOI: 10.1088/1004-423X/2/1/001 Abstract ( 1340 )   PDF (167KB) ( 495 )   Natural rubidium is a mixture of the two isotopes, 85Rb and 87Rb, the natural abundances of which are 72.2 and 27.8 percent, respectively. Taking into account their hyperfine structure, we have cal-culated the Faraday anomalous dispersion spectra (FADS)of Rb D2 lines in different magnetic fields and observed them experimentally. The theoretical calculations are in good agreement with the experi-mental results. In this paper, we also discuss the results.

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A SINGLE-BEAM OPTICAL TRAP FOR AIR BUBBLES IN A LIQUID AND THE CHANGE OF THE OPTICAL FIELD LIU SI-MIN (刘思敏), ZHANG GUANG-YIN (张光寅), YAN XIANG-JUN (严向军), XU JING-JUN (许京军), JI WEI-XING (纪卫星), WU YUAN-QING (武原庆), GUO RU (郭儒) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  9-14.  DOI: 10.1088/1004-423X/2/1/002 Abstract ( 1294 )   PDF (221KB) ( 508 )   We report a single-beam optical trap for particles with refractive index lower than that of the surrounding medium—the air bubbles in the liquid. This phenomenon is explained by radiation pressure.

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MEASUREMENTS OF RELAXATION OF SPIN POLARIZED 129Xe NUCLEI IN HIGH MAGNETIC FIELDS ZHAO MING-XIN (赵明信), LIU ZI-DONG (刘子东), LI LI-YUN (李丽云), LI SEN-LIN (李森林), WU ZHENG-HUA (吴正华), ZENG XI-ZHI (曾锡之) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  15-21.  DOI: 10.1088/1004-423X/2/1/003 Abstract ( 1301 )   PDF (166KB) ( 520 )   We observed the NMR signal of low-pressure gas 129Xe by laser enhanced method on an MSL-400 NMR spectrometer and measured nuclear spin relaxations of 129Xe gas at various temperatures. The relaxation rate constant of 129Xe-133Cs spin exchange was obtained as (6.8±0.5)×10-16cm-3s-1.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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THE IMPURITY TRANSPORT IN HT-6B TOKAMAK HUANG RONG (黄荣), XIE JI-KANG (谢纪康), LI LIN-ZHONG (李林忠), HE YE-XI (何也熙), WANG SHU-YA (汪舒娅), DENG CHUAN-BAO (邓传宝), LI GUO-XIANG (李国相), WEI LE-HAN (魏乐汉), QIU LI-JIAN (邱励俭) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  22-34.  DOI: 10.1088/1004-423X/2/1/004 Abstract ( 1250 )   PDF (382KB) ( 460 )   The quasi-stationary profiles of the impurity ionization stages in HT-6B Tokamak were absolutely determined by monitoring the VUV and visible line emissions. An impurity transport code was set up. The impurity transport coefficients and other parameters about impurities were determined. From the changes of impurity emission profiles, it was concluded that the impurity confinement was improved and the impurity recycling was reduced by the slow magnetic compression along the minor radius. Some characteristics about the impurity transport in this small device are discussed.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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DISLOCATION DISSOCIATION ON CLIMB PLANE IN TEXTURED YBa2Cu3O7-$\delta$ SUPERCONDUCTOR ZHENG JIAN-GUO (郑建国), LI QI (李齐), FENG DUAN (冯端) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  35-41.  DOI: 10.1088/1004-423X/2/1/005 Abstract ( 1288 )   PDF (285KB) ( 869 )   Using high resolution electron microscopy, the structure of [100] tilt boundary with misorientation of 1.2° in YBa2Cu3O7-$\delta$has been determined. The boundary is shown to consist of an array of partial dis-locations, These partials result from the dissociation of a perfect dislocation with a Burgers vector [0, 0, c] on its climb plane according to the reaction, b→b1+b2+b1+b2+b1+b2. Here b=[00c], b1=[O,b/2, c/6} (or [a/2, 0, c/6] ). b2=[0, -b/2. c/6] (or[ -a/2, 0, c/6] ). The spacing between the perfect dislocations satisfies the Read-Shockley formula. There exist no amorphous phases in the boundary region.

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EXPRESSION OF THE ELASTIC ENERGY IN TWO-DIMENSIONAL QUASICRYSTALS HU CHENG-ZHENG (胡承正), DING DI-HUA (丁棣华), YANG WEN-GE (杨文革) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  42-47.  DOI: 10.1088/1004-423X/2/1/006 Abstract ( 1338 )   PDF (164KB) ( 515 )   The application of group theory to elasticity in two-dimensional (2D) quasicrystals is presented. The expression of elastic energy as a function of gradients of the phonon and phason fields has been derived to quadratic order. The phonon response to an external stress is isotropic, but the response of phason field is anisotropic for eightfold and twelvefold symmetries.

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GROWTH CHARACTERISTICS OF DIAMOND FILMS DEPOSITED ON Si AND W SUBSTRATES ZHANG FANG-QING (张仿清), ZHANG WEN-JUN (张文军), ZHANG YA-FEI (张亚菲), CHEN GUANG-HUA (陈光华), GAO QIAO-JUN (高巧君), JIANG XIANG-LIU (蒋翔六) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  48-55.  DOI: 10.1088/1004-423X/2/1/007 Abstract ( 1259 )   PDF (417KB) ( 575 )   Growth characteristics of diamond films synthesized by using a dc arc discharge plasma CVD were studied by means of XRD,SEM and reflection electron diffraction. The results showed that columnar growth of the diamond films was observed, the columns having an average diameter of about 15μm, with sharp and regular base edges. Diamond grains grows on the substrata were initially of uniform polygons. An interfacial transition layer of polycrystalline SiC was observed between the diamond film and Si substrate. Diamond grains grown during the early-stage on W substrate were also uniform, and an interfacial transition layer of polycrystalline WC was observed between the diamond film and the substrate.

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

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INVESTIGATION OF THE EFFECT OF SLOW NEUTRON IRRADIATION ON HALOGEN-DOPED HIGH-Tc SUPERCONDUCTORS AND ITS MECHANISM JIN JI-RONG (金继荣), JIN XIN (金新), JI HE-LIN (吉和林), ZHANG YI-TONG (张贻瞳), XU XIAO-NONG (徐小农), SHI ZHI-XIANG (施智祥), ZHANG ZHI-PING (张治平), YAO XI-XIAN (姚希贤), ZHUANG RUI-FANG (庄瑞芳), XIE HUI (谢晖) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  56-64.  DOI: 10.1088/1004-423X/2/1/008 Abstract ( 1197 )   PDF (271KB) ( 718 )   Irradiation effect of low-fluence (-108 n/cm2 ) slow neutrons on halogen-doped superconductors is presented in this paper. And the mechanism of the effect is also described from the viewpoint of nuclear physics for both fast and slow neutrons on high-temperature superconductors (HTSC). It is shown ex-perimentally and theoretically that slow neutrons of low fluence has a similar irradiation effect to that of fast neutron beams with an energy En>0.1 MeV and fluence 1016-1018 n/cm2-However,quite differ-ent mechanisms are involved in them: Fast neutrons transfer their energies through elastic scattering in HTSC, whereas slow neutrons give off their energies during the slow neutron capture (n, $\gamma$) reaction.

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Li ION BACKSCATTERING STUDY ON HIGH-Tc YBaCuO AND GdBaCuO SUPERCONDUCTOR FILMS JIANG WEI-LIN (江伟林), ZHENG ZONG-SHUANG (郑宗爽), ZHU PEI-RAN (朱沛然) Acta Physica Sinica (Overseas Edition), 1993, 2 (1):  65-71.  DOI: 10.1088/1004-423X/2/1/009 Abstract ( 1084 )   PDF (162KB) ( 332 )   Rutherford backscattering (RBS) measurements of 4.2 MeV Li and 2.4 MeV He ions were done for YBaCuO and GdBaCuO high-Tc, superconductor films deposited on MgO and SrTiO3 single crystalline substrates and for their bulk samples. Energy spectra of both ions were calculated using the RBS analysis program rewritten by the authors. Comparisons between these two non-destructive tech-niques showed some advantages in analyzing the layer thickness and composition ratios of those thin films by MeV Li ions backscattering. Estimated errors are within 7 % for the measured elemental con-centrations and l0 % for the layer thickness in our experiments. A brief discussion is also made of the results.