Table of contents

20 December 1997, Volume 6 Issue 12 Previous issue    Next issue

CLASSICAL AREAS OF PHENOMENOLOGY

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TRANSIENT OPTICAL VORTICES IN THE PROCESS OF PATTERN FORMATION IN A KERR SLICE SYSTEM WITH SINGLE FEEDBACK DING LI (丁立), XIE PING (谢平), DAI JIAN-HUA (戴建华), WANG PENG-YE (王鹏业), ZHANG HONG-JUN (张洪钧) Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  881-889.  DOI: 10.1088/1004-423X/6/12/001 Abstract ( 1329 )   PDF (277KB) ( 368 )   The transient process of the optical pattern formation in a Kerr medium is numerically studied. We find that the process is accompanied by transient optical vortices in the far field. The temporal evolutions of the appearance and disappearance of the vortices are presented. All vortices will vanish when the system approaches its steady state. The number of vortices versus time is given.

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A UNIVERSAL MODULATION FUNCTION AND A GENERALIZED ANALYTICAL SOLUTION FOR PHOTOREFRACTIVE TWO-WAVE COUPLING WANG XUE-REN (王学仁) Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  890-894.  DOI: 10.1088/1004-423X/6/12/002 Abstract ( 1122 )   PDF (138KB) ( 328 )   We proposed a universal form of the modulation function,and derived a generalized analytical solution of the two wave coupled equation in transmission geometry in photorefractive crystal corresponding to the universal modulation function. The generalized analytical solution can be transformed into different analytical solutions reported in previous works on different conditions.In addition, other new analytical solutions can be obtained from the generalized analytical so lution,and an example is given in the present paper.

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

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EFFECT OF MANGANESE SUBSTITUTION IN R2AlFe16-x Mnx(R=Y,Ho,Nd AND Pr)COMPOUNDS ON STRUCTURAL AND MAGNETIC PROPERTIES HAO YAN-MING (郝延明), YAN QI-WEI (严启伟), ZHANG PAN-LIN (张泮霖), SUN XIANG-DONG (孙向东), WANG FANG-WEI (王芳卫), SHEN BAO-GEN (沈保根) Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  895-900.  DOI: 10.1088/1004-423X/6/12/003 Abstract ( 1378 )   PDF (175KB) ( 682 )   The structural and magnetic properties of R2AlFe16-xMnx(0≤x≤8 for Y,Ho,0≤x≤10 for Pr, 0≤x≤16 for Nd) compounds have been investigated by means of X-ray diffraction and magnetization measurements.The R2AlFe16-xMnx compounds have a hexagonal Th2Ni17-type structure for R=Y and Ho, and a rhombohedral Th2Zn17-type structure for Nd and Pr.With increasing x, the unit-cell volumes have a small increase initially,followed by a greater linear increase.The Curie temperature and the saturation magnetizati on of these compounds show marvelous drop with increasing x. Compensation point was observed in the temperature dependence of the magnetization for Ho2AlFe12Mn4 compound.

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STRUCTURES,Pd SPACER POLARIZATION AND MAGNETIC PROPERTIES OF Co-Nb/Pd MULTILAYERS MEI LIANG-MO (梅良模), YAN SHI-SHEN (颜世申), LI MIN (李民), LIU YI-HUA (刘宜华), T.P.Ma, R.C.Barker Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  901-912.  DOI: 10.1088/1004-423X/6/12/004 Abstract ( 1160 )   PDF (401KB) ( 422 )   Magnetic multilayers ［Co-Nb(1.5 or 3.6 nm)/Pd(x nm)］40 were fabricated by radio frequency sputtering synthesis.The structures and magnetic properties of the Co-Nb/Pd multilayers were studied by X-ray diffraction,vibrating sample magnetometer,torque magnetometer and ferromagnetic resonance measurements.The oscillatory dependence of the phase structure,the strain,the ferromagnetic inter layer coupling and the spacer polarization of multilayers on the increase of Pd spacer thickness was observed.The relationship among phase structure,strain,inte rlayer coupling and the polarization of Pd spacers was discussed.The magnetic polarization of Pd spacers will enhance the ferromagnetic coupling between magnetic layers and will restrain antiferromagnetic coupling to occur.The spin dependent electron transport along the normal direction of multilayers and its exchange interaction play key roles in causing these oscillatory behaviors.

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DIELECTRIC RELAXATION BEHAVIOR OF CERAMICS IN THE Pb(Zn1/3Nb2/3)O3-BaTiO3-PbTiO3 SYSTEM YUE ZHEN-XING (岳振星), WANG XIAO-LI (王晓莉), ZHANG LIANG-YING (张良莹), YAO XI (姚熹) Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  913-920.  DOI: 10.1088/1004-423X/6/12/005 Abstract ( 1278 )   PDF (250KB) ( 408 )   The dielectric properties of ceramics in Pb(Zn1/3Nb2/3)O3-BaTiO3-PbTiO3 system were characterized using dielectric-temperature spectra. A spontaneous (zero field) relaxor-normal ferroelectric tran sition was observed for tetragonal rich compositions. A significant hysteresis effect accompanied by this transition, similar to first-order phase transition of normal ferroelectrics. This behavior was different from that of other relaxors, in which such transitions occurred only under a biased dc field. This observation was explained in terms of a thermally driven transformation from an ensemble of polar microregions to normal long-range ferroelectric state (micro-macro domain transition), which was attributed to the internal field resulting from the tetragonal strain.

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ELECTROLUMINESCENCE OF POLYMER DOPED WITH TRIPHENYL-2-PYRAZOLINE DENG ZHEN-BO (邓振波), S.T.LEE (李述汤), CHEN LI-CHUN (陈立春), DONG SHU-ZHONG (董树忠), SUN HENG-HUI (孙恒慧), WANG XUN (王迅) Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  921-926.  DOI: 10.1088/1004-423X/6/12/006 Abstract ( 1246 )   PDF (190KB) ( 496 )   Poly-phenylquinoxaline is used as the electroluminescent( EL) materials to fabricate the thin film electroluminescent devices by the spin coating method. Doped with 1,3,5-triphenyl-2-pyrazoline,the EL spectrum of the devices is shifted to the blue-green region with its peak located at 465nm. The incorporation of a hole transport layer,poly-vinylcarbazole,will enhance the EL intensity,and the quantum efficiency is estimated to be 0.2%. Thus,the devices can be driven by either positive or negative bias(or ac voltage) even though the currentvoltage curve possesses a rectifying property.

GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS

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OSCILLATIONS DRIVEN BY 3He IN THE NUCLEAR REACTION SYSTEM DISTURBED BY CONVECTIVE MOTION DU JIU-LIN (杜九林) Acta Physica Sinica (Overseas Edition), 1997, 6 (12):  927-932.  DOI: 10.1088/1004-423X/6/12/007 Abstract ( 1127 )   PDF (174KB) ( 377 )   The nuclear reactions in the solar interior are always influenced by the effects from convection, diffusion,pressure,gravitation,etc.,among which the convection is primarily responsible for driving the instability.On the basis of the charact eristic with which the particle number density of chemical compositions changes, we investigate the dynamical behaviors driven by 3He in the proton prot on nuclear reaction chain disturbed by convective motion with the aid of nonequi librium dynamics.The new supercritical oscillations of 3He are found in producing and destroying 3He in the nuclear reaction zone of the sun.The energy generation is therefore oscillating,and then this might change the predicted 8B and 7Be neutrino fluxes.