Table of Content

20 January 1992, Volume 1 Issue 1    Next Issue

GENERAL

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THE INHOMOGENEOUS PERIODIC STATES IN A COUPLED MAP LATTICE DING E-JIANG, Lü YAN-NAN 1992, 1 (1):  3-10.  doi: 10.1088/1004-423X/1/1/001 Abstract ( 0 )   PDF (156KB) ([an error occurred while processing this directive])   Numerical method is used to study the inhomogeneous periodic states in a coupled map lattice, and some scaling relations are obtained. The statistical language is proven to be suitable to describe the inhomogeneous periodic states because of its sensitive dependence on the initial conditions.

ATOMIC AND MOLECULAR PHYSICS

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NON-BOLTZMANN ENERGY LEVEL DISTRIBUTIONS OF ARGON ATOMS IN THE INDUCTIVELY COUPLED ARGON PLASMA HUANG MAO, LIU KE-LING 1992, 1 (1):  11-18.  doi: 10.1088/1004-423X/1/1/002 Abstract ( 0 )   PDF (221KB) ([an error occurred while processing this directive])   Based on collisional and radiative processes occurring in the inductively coupled plasma, non-Boltzmann energy level distributions of argon atoms are calculated under various conditions, by using ideal gas law and solving rate equations.

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STUDY OF HIGH-LYING EXCITED STATES OF RARE-EARTH ELEMENT Dy BY LASER RESONANCE IONIZATION SPECTROSCOPY ZHOU HAI-JUN, XU XIANG-YUAN, HUANG WEN, LI LIANG-QUAN, CHEN DIE-YAN 1992, 1 (1):  19-26.  doi: 10.1088/1004-423X/1/1/003 Abstract ( 0 )   PDF (200KB) ([an error occurred while processing this directive])   This paper describes the investigation of high-excited states of Dy. which includes the measurement of high Rydberg states and autoionizing states, by means of laser resonance ionization spectroscopy (LRIS). Two high Rydberg series (n>40), 4f10(5I8) 6sns and 4f10(5I8) 6snd, have been obtained by exciting the state of 4f10(5I8) 6s6p (3P02) 5I08 using two-step laser excitation-electric field ionization method. With the data obtained, we determined the first ionization potential of Dy. It is 47901.7±0.6 cm-1, that is. about one order more accurate than the results given in the literature. Using the same technique, we found 97 autoionizing states by exciting the state of 4f95d6s(7H07).

CLASSICAL AREAS OF PHENOMENOLOGY

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ANALYSIS OF THE GENERAL EFFECTS IN DOUBLE-GRATING DIFFRACTION-INTERFERENCE SYSTEM ZHAN LI, TU JIN-HONG, GUO JIA-RONG 1992, 1 (1):  27-44.  doi: 10.1088/1004-423X/1/1/004 Abstract ( 0 )   PDF (439KB) ([an error occurred while processing this directive])   Based on the ambiguity function, the optical phenomena of the double-gearing diffraction-interference system are analysed with partially coherent illumination. Different patterns are observed on the observation plane when the optical elements are placed in their proper positions. Detailed discussions on the two extremes of coherence are given. Conclusions could be obtained about the Lau effect, the generalized Lau effect, the incoherent grating-lens imaging, the Talbot effect, the joint-Talbot effect and the generalized joint-Talbot effect. Some special cases are also verified by experiments.

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

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FIRST-PRINCIPLE SELF-CONSISTENT PSEUDOPOTENTIAL CALCULATION OF THE ELECTRONIC STRUCTURES OF SHORT-PERIOD (GaAs)m(AlAs)n SUPERLATT1CES FAN WEI-JUN, GU ZONG-QUAN, XIA JIAN-BAI, LI GUO-HUA 1992, 1 (1):  45-50.  doi: 10.1088/1004-423X/1/1/005 Abstract ( 0 )   PDF (172KB) ([an error occurred while processing this directive])   With the local density approximation, the band structares of the short-period (GaAs)1(AlAs)1 and (GaAs)2(AlAs)1 superlattices are calculated by using the first-principle self-consistent pseudopotential method. The results show that the (GaAs)1(AlAs)1 superlattice is an indirect semiconductor, and the lowest conduction band state is at point R in the Brillouin zone; the (GaAs)2(AlAs)1 superlattice is a direct semiconductor and the lowest conduction band state is at point Γ. The squared matrix elements of transition are calculated. The pressure coefficients of energy gaps of the (GaAs)1(AlAs)1 and (GaAs)2(AlAs)1 superlattices are calculated and compared with those obtained by hydrostatic pressure experiments.

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FAR-INFRARED AND INFRARED REFLECTIONS OF Tl2Ba2Ca2Cu3O10 FILM YE HONG-JUAN, HU CAN-MING, HUANG YE-XIAO, LU XIAO-FENG, WANG ZHI-TAO, ZENG WEN-SHENG, ZHANG GUANG-YIN, YAN SHAO-LIN 1992, 1 (1):  51-56.  doi: 10.1088/1004-423X/1/1/006 Abstract ( 0 )   PDF (170KB) ([an error occurred while processing this directive])   The far-infrared and infrared reflection spectra of Tl2Ba2Ca2Cu3O10 superconducting film are reported in this paper. It is found there are three sharp reflection edges in both the superconducting and normal states, their positions being near ≈ 150, ≈ 350 and ≈600 cm-1. We attribute these reflection spectra to the Drude free carriers and a wide mid-infrared absorption band. When the incident angle increases from 7° to 30°, some additional stractures appear in the refiection spectra, which are the A2u phonon modes vibrating along c-axis.

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MAGNETIC PROPERTIES AND CRYSTALLIZATION OF THE RAPIDLY QUENCHED (Fe1-xNdx) 81.5B18.5 ALLOYS SHEN BAO-GEN, YANG LIN-YUAN, GUO HUI-QUN 1992, 1 (1):  57-62.  doi: 10.1088/1004-423X/1/1/007 Abstract ( 0 )   PDF (186KB) ([an error occurred while processing this directive])   Magnetic properties and crystallization behaviors of amorphous (Fe1-xNdx) 81.5B18.5 alloys were studied. The crystallization temperature is found to rise at first and then drop monotonically with x, having a maximum value of 976K at x=0.11 (9at% Nd). The (Fe1-xNdx) 81.5B18.5 alloys prepared at a quenching rate of vs = 6.6m /s are amorphous, and exhibit good glass formability. Both the coercive field Hc and energy product (BH)max depend strongly on Nd concentration. Amorphous (Fe1-xNdx) 81.5B18.5 alloys with higher Nd concentration have a high coercive field at low temperature, due to the large random uniaxial anisotropy of Nd. The room-temperature Hc and (BH)max obtained on optimal annealing con-ditions show two maxima as a function of Nd concentration x. The highest room-temperature coercive field Hc =22 kOe within the Nd concentrations around x=0.368 and the maximum energy product(RH)max= 13.3 MG·Oe at x =0.055 are observed. The hard magnetic properties of these crystallized samples are related to the presence of the bard magnetic Nd2Fe14B phase.

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DYNAMICS OF CARRIER CAPTURE IN AlGaAs/GaAs MULTIPLE QUANTUM WELLS LIN WEI-ZHU, PENG WEN-JI, QIU ZHI-REN, ZHOU XUE-CONG, MO DANG 1992, 1 (1):  63-68.  doi: 10.1088/1004-423X/1/1/008 Abstract ( 0 )   PDF (187KB) ([an error occurred while processing this directive])   Dynamics of carrier relaxation and capture in AlGaAs/GaAs multiple quantum wells (MQW) at 80 K is studied using picosecond luminescence and femtosecond absorption saturation measurements. Carriers generated in the wells and in the barriers scatter initially out of the excited states to a quasi-equilibrium state in 35 and 400 femtoseconds, respectively, before they are captured into the bound states of the quantum wells. Carrier capture occurs during carrier cooling and recombination. A carrier capture time of 25 ps has been deduced from time-resolved luminescence.