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Vol. 37, No. 9 (1988)

1988-05-05
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CONTENT
AMANY-BODY UNIVERSAL APPROACH TO THERMALLY ACTIVATED MAGNETOELASTIC RELAXATION IN FERROMAGNETIC ALLOYS
WANG YANG-PU, JIN QI-SMU
1988, 37 (9): 1401-1405. doi: 10.7498/aps.37.1401
Abstract +
The rmally activated magnetoelastic relaxation in disordered ferromagnetic alloys is studied by using a new relaxation mechanism based on the concept of many-body interaction leading to an infrared divergence response. It nas been found that except the thermally assisted transitions of directional ordered atoms, the directional ordering, which causes a relaxation behavior of magnetic domain walls, includes two different classes of configurational tunnelling caused by many-body interactions. Based on this mechanism, a new relaxation law of magnetization and a new formula of magnetic disaccommodation were derived. Using Boltzmann superposition principle, an universal formula of internal friction was also derived, which was verified by experimental date.
GREEN'S FUNCTION THEORY OF PHASE TRANSITION IN ORDER-DISORDER TYPE FERROELECTRICS AND ANTIFERROELECTRICS
LI TING, QIN ZI-KAI
1988, 37 (9): 1406-1414. doi: 10.7498/aps.37.1406
Abstract +
In this paper, we use the Green's function method with the symmetry decoupling scheme to study the phase transition in H-bond ferroelectric system. Some interesting results are obtained. Also, we find that the temperature and the order parameter at transition point, Tc and Sc, can be determined directly from the T-S relation, and the order of phase transition can be obtained naturally. The results are discussed in detail and compared with experiments.
RESONANCE FLUORESCENCE OF AN ADATOM NEAR THE SURFACE OF A PERIODIC OR QUASI-PERIODIC SUPERLATTICE FILM
LI XIAO-SHEN, GONG CHANG-DE
1988, 37 (9): 1415-1424. doi: 10.7498/aps.37.1415
Abstract +
Resonance fluorescence spectrum and squeezing phenomenon are studied for an adatom near the surface of a periodic or quasi-periodic superlattice film using the surface-dressed optical Bloch equations. The influences of thickness and dielectric properties of each layer composing this film, number of layers, and geometry structures are discussed.
A STUDY OF DAMAGE IN SILICON CREATED BY P2+ IMPLANTATION
FANG ZI-WEI, LIN CHENG-LU, ZOU SHI-CHANG
1988, 37 (9): 1425-1431. doi: 10.7498/aps.37.1425
Abstract +
The damage and annealing behavior of Si implanted at room temperature with P2+ and P+ at different energies (5-600 keV) and intermediate dose (~1014/cm2) has been investigated. Experimental results show that the damage created by P2+ implantation is always greater than that of P+ implantation. The ratio of total displaced atoms of the target cuased by molecular and ND(mol)/ND(atom)reached a maximal value at 100 keV (P2+)and 50 keV (P+) after rapid thermal annealing, the carrier concentration profiles measured by spreading resistance measurement are also different for the P2+ and P+ implanted samples. We attribute essentially this phenomenon to the displacement spike, but the multiple collision effect and the interaction between two molecular fragments should be considered when the incident energy is high.
DIFFRACTION OF ULTRASHORT LASER PULSES
HAN QUAN-SHENG, ZHU ZHEN-HE
1988, 37 (9): 1432-1437. doi: 10.7498/aps.37.1432
Abstract +
The energy distribution of the diffraction fields of the transform-limited ultrashort laser pulses is inspected. By calculating the single- and doubleslit diffraction of the transform-limited pulses, the dependence of diffraction patterns on the pulse duration is revealed. It is indicated that the information about the pulse durations and shapes can be obtained through the diffration inspection.
THE MULTI-PHOTON QUANTUM STATITISCAL THEORY OF DRIVEN OPTICAL SYSTEMS (II)——BAD CAVITY CASE
ZHANG LIN, LIN REN-MING, HUANG SI-XIAN
1988, 37 (9): 1438-1449. doi: 10.7498/aps.37.1438
Abstract +
In this paper, the multi-photon FPE of driven optical systems are treated for bad cavity case. The semi-classical linear stability analysis are performed. The non-classical effects are discussed, and it is shown that in two-photon case the atom-atom correlation enhances the non-clasical effects. This is in opposite to the single-photon case, and different from the good cavity case. The two-photon spectrum of transmitted light and resonance fluorescense are obtained, where the Rabi frequency Ω∝y2 (y is the incident field).
SYMMETRIZATION ANALYSIS OF VIBRATIONAL MODES AND STUDY OF RAMAN SPECTRA FOR MOLECULAR CRYSTAL RbC8H5O4
HONG SHUI-LI
1988, 37 (9): 1450-1460. doi: 10.7498/aps.37.1450
Abstract +
Based on the feature of molecular crystal, we apply the theorem that the foctor group of the space group is isomorphic to the point group and combine with the method of structural analysis, to classify the modes of internal vibrations of RbC8H5O4 directly according to the compatibility relations of the irreducible representations. For spectra of the fundamental frequency coupling and Fermi resonance in vibration spectra, we have to make determination according to the space relative position of each functional group and symmetrization of each fundamental direct product representation. Raman scattering spectra of three kind of isomor-phous crystal (i.e, RAP, TAP and KAP) have been obtained and compared with each other. The modes of external vibrations in crystal lattice was then isolated from the overall spectra.
PLANE AND SPHERICAL WAVES SOLUTIONS OF THE FIELD EQUATION FOR A COMPLEX SCALAR FIELD WITH A CUBIC NONLINEAR TERM IN FOUR DIMENSIONAL MINKOWSKI SPACE
LI FU-BIN
1988, 37 (9): 1461-1470. doi: 10.7498/aps.37.1461
Abstract +
The field equation for a complex scalar field with a cubic nonlinear term in tour-dimensional Minkowski space is studied. Two classes of exact solutions, corresponding to solutions of plane and spherical waves, are presented.
THE MECHANISM OF THE PROPERTY CHANGE OF THE MIXED Agl(Cr2A3) IONIC CONDUCTOR
WANG YU-XIA
1988, 37 (9): 1471-1479. doi: 10.7498/aps.37.1471
Abstract +
We study the infrared absorption spectrum, the ultraviolet and visible reflection spectrum of the Agl(Cr2O3) mixed ionic conductor, as well as its micro shape and result of composition analysis obtained with TEM. It is found that there exists some diffrence between Agl(Cr2O3) maxed ionic conductor and the pure Agl, Cr2O3 with microcosmic meticulous structure.A new model of the electrical medium is developed. According to the micro shape, we expect that the reason of the change in the microcosmic meticulous is the deformation electrical polorzation has been deformed. The mechnism of the property change of the AgI(Cr2O3) mixed inonic conductor is discussed.
FRACTAL GROWTH OF NICKEL-BASED ALLOYS IN THIN FILMS
HUANG LI-JI, DING JU-REN, LI HENG-DE, LIU BAI-XIN
1988, 37 (9): 1480-1485. doi: 10.7498/aps.37.1480
Abstract +
In this article, we report the formation of fractal structures in nickel-based alloy systems, in thin films during ion beam-solid interactions. The experimental results show that a necessary condition for the fractal growth in thin films is amorphous structural phase transition in the amorphous matrix. The fractal dimensions of the observed patterns depended on the specific alloy systems: Df = 1.4 for Ni-Zr system and Df=1.7 for Ni-Mo system. The relationship among ion-solid interaction, amorphous structural phase transition and the fractal growth in thin films is also discussed.
AN ANALYTICAL STUDY ON THE SCALING PROPERTIES OF DIFFUSION-LIMITED AGGREGATION IN EXTERNAL FIELDS
YU JIANG, HU GANG
1988, 37 (9): 1486-1493. doi: 10.7498/aps.37.1486
Abstract +
We have investigated the scaling properties of DLA clusters grown in the various kinds of external fields, using the meanfield theory with the continuum approximation. Our results show that the density of the growing cluster, ρ, initially dropping as 1/r, and becomes a constant value for constant external field. For the fields of type 1/rα we find that the aggregates exhibit very complicated, non-trivial scaling behaviours with the control parameter a varying.
BRIEF REPORT
PARTIAL-WAVE ANALYSIS OF 1Se STATES OF HELIUM ATOM AND STRONG RADIAL-ANGULAR CORRELATION REGIONS
BAO CHENG-GUANG
1988, 37 (9): 1494-1498. doi: 10.7498/aps.37.1494
Abstract +
The 1Se states of the helium atom have been calculated by diagonalizing the hamiltonian in a model space which is a union of four subspaces. The eigenwavefunctions have been analysed in detail and some features of internal structure have been found.
A NEW METHOD FOR STUDING THE SPECTRAL LINE STRUCTURE
ZHAO BAO-CHANG, LI CHUN-FANG, XUE MING-QIU
1988, 37 (9): 1499-1504. doi: 10.7498/aps.37.1499
Abstract +
The attempt to reconstruct high resolution spectrum using the interferogram of the Fabry-Perot interferometer has been achieved theoretically by solving an integral equation. But ordinarily, the solution of the equation is unstable. It is necessary to keep the antinoise ability at a level of 10-4 At present, it is very difficult to manufacture such a device, which attains this level. It is demonstrated by using computer simulation experiments that solving of the equation will become rather stable under certain conditions and the antinoise ability can be enhanced to 10-2. This result makes it possible to develop a satisfactory device.
A STUDY ON THE RELATIONSHIP BETWEEN THE SPONTANEOUS RADIATION AND THE STIMULATED RADIATION IN TRANSITION RADIATION FREE ELECTRON LASERS
LIU SHENG-GANG, SUN YAN
1988, 37 (9): 1505-1509. doi: 10.7498/aps.37.1505
Abstract +
As a fundamental theorem in free electron lasers, Madey Theorem reveals the relationship between the spontaneous radiation and the stimulated radiation. In this paper, this problem is studied for transition radiation free electron lasers. The results show that there is a formula corresponding to the first part of Madey Theorem, but the former is more complicated; while the second part remains the same. Then the results obtained are used to simplify the small signal gain calculation.
THE NEW LASING OF Rb ATOM IN NOBLE GAS SYSTEM
LU YI-QUN, ZHANG BING
1988, 37 (9): 1510-1516. doi: 10.7498/aps.37.1510
Abstract +
A new lasing of Rb atom in noble gas system excited by the argon laser (4579 ?) was observed. The lasing originates from the transition between the 5d state and 5p state of Rb atom. The wavelengths are 7760 ? and 762l?.
EXPERIMENTS OF PRODUCING SLOW POSITRON BEAM
HAN RONG-DIAN, GUO XUE-ZHE, WENG HUI-MIN, XIE LI, ZHANG SHAO-QIANG
1988, 37 (9): 1517-1521. doi: 10.7498/aps.37.1517
Abstract +
In this article, we describe an apparatus for producing a slow-positron beam by moderating the decay positrons from a radioactive source using a W-vane moderator. The integral energy spectrum of the slow-positrons was measured with a retarding field analyser. The results are compared with that obtained using a Ni+MgO moderator at the same apparatus.
STUDY OF DOMAIN VOLUME IN POLYURETHANE IONOMER
JIANG CHENG-HUA, YI CHUAN-YUAN, WANG HUA-QIN
1988, 37 (9): 1522-1526. doi: 10.7498/aps.37.1522
Abstract +
A sample of polyurethane ionomer is studied by small angle X-ray scattering, positron annihilation and density measurement. The experimental results demonstrate that the counter-ion radius, domain volume and density of polyurethane ionomer increase and free volume decreases with valency of the metal ion increasing. The application ranges of small angle X-ray scattering and positron annihilation are discussed and showed that positron annihilation is one of significant methods for studying domain volume in ionomer.
TEMPERATURE DEPENDENCE OF HARD BUBBLE FORMATION IN PULSE BIAS FIELDS
NIE XIANG-FU, SUN HUI-LING, OUYANG FANG-LI, TANG GUI-DE, XIU JIA-FA, HAN BAO-SHAN
1988, 37 (9): 1527-1533. doi: 10.7498/aps.37.1527
Abstract +
The temperature dependence of VBL group formation in stripe domain walls of epitaxial garnet bubble films was investigated by means of the method of single-pulse bias field. A critical temperature T02 was found, which relats to the parameters of bubble films. When T >T02, hard bubbles no longer form. It was also found that, when T02, there are two different stages for VBL group formation. Their demarcation temperature is T01. The experimental curves in the first stage have been qualitatively interpreted. And the difference of soft domain segment movements, which lead ro their hardening, in the two stages has been revealed by means of the method of double exposure photography.
STRUCTURAL AND MAGNETIC PROPERTIES OF Sm (Ti, Fe)12 INTERMETALLIC COMPOUNDS
YANG YING-CHANG, KONG LIN-SHU, CHENG BEN-PEI
1988, 37 (9): 1534-1539. doi: 10.7498/aps.37.1534
Abstract +
The rare earth-iron intermetallic compounds of SmTiFex with x ranges from 8 to 11, was synthesized by are-melting technic. We found that they crystallize in the ThMn12-type tetragonal structure, 14/mmm. We report here the crystallographic and magnetic properties of Sm(Ti, Fe)12 and Gd (Ti, Fe)12. Unusual uniaxial magnetocrystalline anisotropy was observed in Sm(Ti, Fe)12 compounds. For Sm(Ti, Fe)12, the c-axis is the easy magnetization direction, and Curie temperature is 610 K. The magnetizrystalline anisotropy of Sm and Fe sublattices in Sm(Ti, Fe)12 compounds was analyzed by measuring magnetization curves of Gd(Ti, Fe)12. On the basis of our data, we conclude that both Sm and Fe sublattices have easy axis. After the discovery of Nd2Fe14B magnets, Sm(Ti, Fe)12 is another ternary rare earth-iron intermetallic compounds with strong uniaxial anisotropy.
THE HYDROGENATION OF THE AMORPHOUS ALLOY Fe87V3Zr10
XU ZU-XIONG, MA RU-ZHANG, DUO LIANG, DING WEI-QING
1988, 37 (9): 1540-1544. doi: 10.7498/aps.37.1540
Abstract +
The hydrogenation of the amorphous alloy Fe87V3Zr10 is studied using secondary ion mass spectroscopy (SIMS) and Mossbauer spectroscopy (MS). It is shown that the atoms of hydrogen in charged samples combine preferentially with atoms of zirconium and produce clusters of ZrH, and a proportion of hydrogen combine with atoms of vanadium and iron and produce clusters of VH and FeH. the mechanism that hydrogen influences the magnetism of this alloy is discussed.
SURVEY OF PREBREAKDOWN PARAMETERS OF NF3
LI ZHENG-YING
1988, 37 (9): 1545-1549. doi: 10.7498/aps.37.1545
Abstract +
Using the pulsed drift-tube-mass spectrometer system, we measured the prebreakdown pa-rameters of NF3 mixtures used in excimer lasers or produced in discharges of SF6 mixtures, including electron attachment coefficients, attachment rate coefficients, ionic mobilities and kinds of negative ions. The relations between electron attachment rate coefficients and mean electron energies are measured as well.
A NOTE ON THE GROUND STATE OF STRONG ELECTRON-PHONON INTERACTING SYSTEM
ZHENG HANG
1988, 37 (9): 1550-1555. doi: 10.7498/aps.37.1550
Abstract +
In this paper, a new variational ground state of strong electron-phonon interacting system is proposed, in which the electron subsystem is in superconducting pairing state and the phonon subsystem in two -phonon coherent state. We show that such a variational state is necessary for obtaining a superconducting condensation energy with reasonable magnitude and for the effective mass of the charge carriers not being too large.
IN-SITU STUDY OF THE SUPERCONDUCTING TRANSITION AND INTERNAL FRICTION OF HIGH Tc SUPERCONDUCTOR YBaCuO
DU JIA-JU, JIANG JIAN-YI, WANG XIANG, YIN HUA-QING
1988, 37 (9): 1556-1559. doi: 10.7498/aps.37.1556
Abstract +
The resistance, internal friction and Young's modulus of a high Tc superconductor-YBa2Cu3O7-δ were measured in-situ at 80 K to 300 K. Two obvious peaks of internal friction were observed near Tc On account of character of the peaks, we suggest that these two peaks are associated with the eletronic relaxation between Cu3+ and Ca2+ The peak and anomalies of Young's modulus observed in the range of 160 K to 280 K may be related to the position adjustment of oxygen vacancies.
INFLUENCE OF OXYGEN DEFICIENCY ON THE THERMOELECTRIC POWER IN SINGLE PHASE YBa2Cu3O7-x SYSTEM
ZHANG QI-RUI, RUAN YAO-ZHONG, HU XUE-LONG, LI LI-PING, ZHAO YONG, PAN GUO-QIANG, CHEN ZU-YAO
1988, 37 (9): 1560-1563. doi: 10.7498/aps.37.1560
Abstract +
The influence of oxygen deficiency on the superconductivity and the thermoelectric power in single phase YBa2Cu3O7-x system was studied. The results show that the superconducting transition temperature decreases, and the magnitude of the thermoelectric power increases with the amount of oxygen vacancies. From the experimental results we suggest that holes conduction is predominant in single phase YBa2Cu3O7-x system, the relatively large phonon-drag thermopower indicates that there exists strong electron-phonon interaction in YBa2Cu3O7-x superconductors.
EXACT SOLUTION OF A GENERALISED MIXED SPIN MODEL ON DISORDER DOMAIN
TANG KUN-FA, HU JIA-ZHEN
1988, 37 (9): 1564-1568. doi: 10.7498/aps.37.1564
Abstract +
A condition given by Baxter for the general IRF model to exhibit a disorder solution is applied to a generalised mixed spin model. The exact expression for the free energy and the condition ensuring the validity of it are obtained. The asymptotic behaviour of the intra-row correlations is discussed.
AN IMPROVEMENT OF KOSSEL RATIO METHOD
HUANG RONG, WANG GUAN-YING
1988, 37 (9): 1569-1574. doi: 10.7498/aps.37.1569
Abstract +
An improvement of revised Kossel ratio method is put forward in this paper, at the same time a Kossel orientation method of crystal is developed. It can analyse more Kossel patterns than generally used ratio method. It is applied to a arbitrarily orientation Kossel pattern of a Fe-0.76wt%V-0.08wt%N alloy. The accuracy of the lattice parameter determination reaches 5×10-5?.