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Vol. 39, No. 9 (1990)

1990-05-05
Topics
GENERAL
STRUCTURE CONSTANTS OF QUANTUM ALGEBRA AND YANG-BAXTER RELATION FOR THE Zn-SYMMETRIC STATISTICAL MODEL
WEI HUA
1990, 39 (9): 1357-1362. doi: 10.7498/aps.39.1357
Abstract +
The Zn-symmetric solution of Yang-Baxter equation in statistical mechanics is analyzed with care, the structure constants of the corresponding quantum algebra are obtained naturally, and a direct proof for this solution is presented.
SOME NEW MULTIPLE SOLITON SOLUTIONS OF HIGH-DIMENSIONAL NONLINEAR WAVE EQUATIONS
HUANG GUO-XIANG, NI GUANG-JIONG, LOU SEN-YUE
1990, 39 (9): 1363-1369. doi: 10.7498/aps.39.1363
Abstract +
By using the base equations technique and the transtormation relations to get new solutions of the base equations, we obtain some new multiple soliton solutions of n+1 dimensional nonlinear wave equations. Gibbon et al. pointed out that the number of the soliton in the multiple soliton solutions is constrainted by N≤2n+1. However, our result shows that their conclusion is not ture, the number of the soliton N may be an arbitrary positive integer.
ATOMIC AND MOLECULAR PHYSICS
OBSERVATION AND MEASUREMENT OF THE AUTOIO-NIZATION SPECTRA FOR 4f76s(7S)np SERIES OF Eu
HU SU-FEN, ZHANG SEN, CHEN XING
1990, 39 (9): 1370-1378. doi: 10.7498/aps.39.1370
Abstract +
The autoionization spectra of Eu have been observed by using three-step laser excitation method. Seventy five energy levels of Eu which are located in the 45740.3-47341.0cm-1 energy interval with even parity have been measured. The 4f76s(7S)np (n=12-46) 6PJ autoionization Rydberg series converging to the 7S3 level of the configuration 4f76s in Eu II have been identified. The energy levels and quantum defects for this series in above energy interval are reported.
CLASSICAL AREA OF PHENOMENOLOGY
STUDIES OF RAMAN FREE ELECTRON LASER BY AN OPTICAL KLYSTRON CONFIGURATION
CHEN JI-ZHONG, WANG MING-CHANG, WANG ZHI-JIANG, LU ZAI-TONG
1990, 39 (9): 1379-1384. doi: 10.7498/aps.39.1379
Abstract +
A design of an over-all experiment of Raman free electron laser with an optical klystron configuration is put forward. The gain and efficiency improvement of free electron laser by an optical klystron configuration has been studied by one dimensional single-particle model.
TUNABLE VACUUM-ULTRA VIOLET RADIATION GENERATED BY TWO-PHTON RESONANTFOUR-WAVE DIFFERENCE MIXING IN Hg VAPOR
HUANG XIAN-LING, XIA ZONG-JU, ZOU YING-HUA
1990, 39 (9): 1385-1392. doi: 10.7498/aps.39.1385
Abstract +
Vacuum-ultra violet radiation is generated by 61S0-61D2 or 61S0-63D2 two photon resonant four-wave difference mixing (ω4=2ω1-ω3) in Hg vapor. VUV radiation is tunable when one of the input wave (ω3) is tuned, the tuning range is 184.9-187.5 nm. The mechanism of this frenquency conversion, for example, the two-photon and single-photon resonant enhancement and phase matching have been investigeted. The competing processes and saturation effect on conversion efficiency have been analyzed. Using the generated tunable VUV radiation, we have recorded the absorption spetrum of O2 in air.
SOLITARY WAVES ON A TWO-LAYER FLUID WITH BASIC CURRENTS
YAN JIA-REN, ZHONG JIAN-XIN
1990, 39 (9): 1393-1399. doi: 10.7498/aps.39.1393
Abstract +
In this paper, we study the interface and surface solitary waves on a two-layer fluid with basic currents. It is found that there are two modes of solitary waves, i.e., the fast mode and rhe slow mode, they are always governed by a KdV equation. The influence of currents on solitary waves is discussed. By using the two-fluid model, the themocline in ocean is studied, the long, weak nonlinear waves in a homogeneous density fluid with shear flow are studied also.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
A SURVEY ON THE LIMITING BREAKDOWN STRENGTH AND ELECTRON ATTACHMENT RATE CONSTANTS IN ELECTRONEGATIVE GAS MIXTURES
LI ZHENG-YING
1990, 39 (9): 1400-1406. doi: 10.7498/aps.39.1400
Abstract +
The relationship between the limiting breakdown strength and the pressure-dependent electron attachment rate constants is discussed. Also discussed are the various types of synergistic behavior in the limiting breakdown strengths including linear, synergism, positive synergism and negative synergism which have been observed in binary dielectric gas mixtures as well as the conditions under which different types of synergistic effects would occur.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
A NEW METHOD FOR SIMULATING HIGH RESOLUTION ELECTRON MICROSCOPE IMAGES FROM NON-PERIODIC OBJECTS
WANG YUAN-MING, HU TIAN-BAO, CHEN JIANG-HUA, ZENG XIAO-BIAO
1990, 39 (9): 1407-1412. doi: 10.7498/aps.39.1407
Abstract +
It is shown that the dynamical diffraction calculation using periodic extension of the sampling boundary points leads to serious and artificial errors in the High Resolution Electron Microscope (HREM) image simulation for a non-periodic object in FFT Multi-Slice (FFTMS) method which is now routinely used for the simulation of HREM images from periodic objects.In a systematic study of the problem of induced numerical artifacts, a new method has been proposed for the HREM image simulation of non-periodic objects. It is based on some improvements in the calculation of the phase grating and the propagation operator to the Real Space Multi-Slice (RSMS) method, which are compatible with a non-periodic object.It can be seen from the comparison with the experimental HREM images that much more better agreement can be obtained by using Real Space Multi-Slice method for Non-periodic objects (RSMSN).
MECHANICAL ALLOY METHOD AND FORMATION ABILITY OF FexAl100-x AMORPHOUS POWDER
WANG GEN-MIAO, CHEN HUI-YU, WANG WEI-HUA, DONG YUAN-DA
1990, 39 (9): 1413-1417. doi: 10.7498/aps.39.1413
Abstract +
The FexA100-x(x = 10, 20,30,40,50, 60, 70) amorphous powder were prepared by ball grinding through different time. The X-ray diffraction indicates that the intensity of diffraction peaks for each sample decreases more and more while the width of peaks becomes wider due to ball grinding time increasing. This results from the formation of amorphous portion in samples. On the other hand, X-ray diffraction and magnetic properties measurements show that to get the same ratio of amorphous in samples, we must take different time to ball grind the different content powder sample, Fe50Al50 crystalline powder can be transformed into amorphous powder most easily.
STUDY OF DEFECTS IN CRYSTAL OF TRIHYDROXYME-THYLAMINOMETHANE BY X-RAY TOPOGRAPHY
ZHAO QING-LAN, HUANG YI-SEN
1990, 39 (9): 1418-1423. doi: 10.7498/aps.39.1418
Abstract +
Trihydroxymethylaminomethane (TAM) is a new crystal analyzer with both chemical stability and X-ray analytical performance better than pentaerythrite(PET). The X-ray topographic experiment results show that there are not only a variety of dislocations with Burgers vectors b=±[100], ±[010], ±[001], ±[101], ±[101] and ± [011] etc, but also macroscopic inclusion arrays or isolate inclusions. The planar defect parallel to (001) plane is occured rarely. Origins of defective formation are discussed briefly.
X-RAY TOPOGRAPHIC CONTRAST OF INCLUSIONS IN THE CRYSTAL OF LOW TEMPERATURE FORM BARIUM BORIC OXIDE
ZHAO QING-LAN, HUANG YI-SEN
1990, 39 (9): 1424-1428. doi: 10.7498/aps.39.1424
Abstract +
The inclusion contrast in the crystal of low temperature form barium boric oxide (BBO) has been studied by use of X-ray topography. Two types of contrasts arranged in equi-triangular cones have been observed experimentally, and believed to be due to the atomic displacemens of Ba.
ELIMINATION OF P SEGREGATION DURING MOLECULAR BEAM EPITAXIAL GROWTH OF Si ON GaP (111) SUBSTRATE
JIANG WEI-DONG, FAN YONG-LIANG, SHENG CHI, YU MING-REN
1990, 39 (9): 1429-1434. doi: 10.7498/aps.39.1429
Abstract +
The segregation of P from substrate to the surface of Si epilayer has been observed during MBE preparation of Si/GaP (111) heterostructure. In this paper, the mechanism of P segregation and relationship between the surface reconstruction and segregation are discussed, according to the results of AES and RHEED under different experimental conditions. The conclusion is that the segregation of P was caused by substituting P atom with Si deposited atom during growth. From this, a new method for eliminating the segregation of P efficiently is proposed.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
INVESTIGATION OF THE VALENCE-BAND STRUCTURE OF GRAPHITE AND THE INTERACTION OF GRAPHITE WITH NICKEL
LUO CHUN-PING, QI SHANG-XUE, LI NAN, LIN ZHANG-DA
1990, 39 (9): 1435-1440. doi: 10.7498/aps.39.1435
Abstract +
The valence-band structure of graphite was investigated by UPS and XPS, and the result was compared with theoretical result of Painter et al. Due to the interaction of C-atom with Ni-atom, Ni3C was observed after vapor deposition of Ni on graphite surface. The C 2px,y orbital is raised up to 5eV below the Fermi lever, while the C 2px orbital is approaching the Fermi lever closely after formation of Ni3C.
CALCULATION FOR g-VALUES OF THE AMORPHOUS Si AND AMORPHOUS Si-BASED ALLOY SEMICONDUCTORS
YU GONG, CHEN GUANG-HUA, SU YU-CHENG, ZHANG FANG-QING
1990, 39 (9): 1441-1445. doi: 10.7498/aps.39.1441
Abstract +
In this paper, the g-values of the ESR signals in amorphous Si and Si-based alloys have been calculated by using the improved CNDO/2 molecular orbital method. The effects of the structural relaxation on the g-valucs have been also discussed. The calculated results are in accord with the experiments.
A NEW GENERAL FORM OF THE KRONIG-PENNEY MODEL SUITABLE FOR SUPERLATTICE STUDIES
YANC GUO-ZHEN, PAN SHAO-HUA, FENG SI-MIN
1990, 39 (9): 1446-1452. doi: 10.7498/aps.39.1446
Abstract +
A new form of the Kronig-Penney model has been developed which is more general and practical than the new form in Ref. [1] . It gives not only odd and even index subbands separately but also wave functions for all k values. Moreover, a thorough analysis of the parity of tin-wave functions can also be given. Hence it affords a more suitable theoretical form for the analysis of superlattices and application to device designs.
DISCUSSION ON NORMAL STATE RESISTIVITY IN A RVB SYSTEM
LIU MEI, XING DING-YU
1990, 39 (9): 1453-1460. doi: 10.7498/aps.39.1453
Abstract +
In terms of the theory of linear response, we have studied the normal state resistivity due to holon-spinon scattering or holon-phonon scattering in a RVB system. The calculated results show that the resistivity due to holon-spinon scattering may be fitted by a formula ρ- Tα with α depending weakly on temperature and varying between 1.4 and 1.5, while the resistivity due to scattering by phonons exhabits linear temperature behavior in a wide temperature range.
EXPLANATION OF THE QUANTIZED MAGNETORESIS-TANCE IN MULTPLY CONNECTED PERIMETERS IN TWO-DIMENSION ELECTRON SYSTEMS
PENG JIAN-PING, ZHOU SHI-XUN
1990, 39 (9): 1461-1464. doi: 10.7498/aps.39.1461
Abstract +
We explain the quantized magnetoresistance in multiply connected perimeters in two-dimensional systems observed by Fang and Stiles based in terms of a model which states that the two-terminal resistance of a two-dimensional electron system in a quantizing magnetic field in any open geometry is given by h/fe2, where f is the Landau filling factor.
SUBBAND STRUCTURE OF GaAs/AlGaAs SUPERLAT-TICES UNDER CROSSED ELECTRIC AND MAGNETIC FIELDS
FAN WEI-JUN, XIA JIAN-BAI
1990, 39 (9): 1465-1472. doi: 10.7498/aps.39.1465
Abstract +
The subband structure and optical transition of GaAs/AlGaAs superlattices are investigated in the presence of an electric field applied along the growth direction and a magnetic field parallel to the GaAs/AlGaAs interface by using the effective mass theory. In the presence of the parallel magnetic field, the twofold degeneracy is removed and heavy and light holes are mixed. The presence of the electric field introduces the Stark shift. The magnetic-optical transition probability is also discussed.
GROUND STATE STUDY OF SPIN S = 1 ISING ANTIFER-ROMAGNETIC MODEL ON FACE-CENTRED CUBIC LATTICE
XU GUO-LIANG, WANG YANG-PU
1990, 39 (9): 1473-1479. doi: 10.7498/aps.39.1473
Abstract +
This paper develops the method presented in reference (1) where the Fermion transformation is used to obtain the ground state of the Ising model. According to that after the Ferrnion transformation, the phase boundary can be obtain using the condition that energy of excited state is greater than zero, we propose that phase boundary can be obtain by directly comparing the energy of the vacuum state. Using this method, we study the most general spin S=1 Ising antifer-romagnetic model with nearest neighbor interaction, and obtain rigorously the ground state energy and the OK phase diagram of the model on fcc lattice. Meanwhile, using equation of many phase point, we divide the plane of parameter k,l into 56 regions, which correspond to topologi-cally distinct OK phase diagrams.
STUDY OF A QUANTUM TRANSVERSE ISING MODEL WITH RANDOM FIELDS
MA YU-QIANG, LI ZHEN-YA
1990, 39 (9): 1480-1487. doi: 10.7498/aps.39.1480
Abstract +
In this paper, we propose a new method, which combines the pair approximation with the discretized path-integral representation, to study the quantum transverse Ising model with random-field. Full phase diagrams are obtained for various random-field distributions. When applied random fields are trimodal (and bimodal), the critical properties including the possibility of the existence of the tricritical points and rcentrance phenomena are numerically analyzed in detail. In the limit z→∞, the extended mean-field result is recovered.
EFFECT OF COMPOSITION AND TRANSITION METALS ON CRYSTALLIZATION TEMPERATURE OF Fe-Zr-BASED AMORPHOUS ALLOYS
CHEN JIN-CHANG, SHEN BAO-GEN, WO FENG, YANG LIN-YUAN, ZHAO JIAN-GAO, GUO HUI-QUN, ZHAN WEN-SHAN
1990, 39 (9): 1488-1493. doi: 10.7498/aps.39.1488
Abstract +
The composition dependence of the crystallization temperature Tcr for Fe100-xZrx,(Fe1-xZrx)84B16 and Fe90-xMxZr10(M = V,Cr,Mn,Co,Ni,Si,B) amorphous alloys is investigated systematically. The main results are: the substitution of Zrfor some Fe in Fe-based amorphous alloysTcr exhibits an increase markedly; for amorphous Fe90-xMxZr10 alloys, Tcr increases following the order M = Mn, Cr, V and with increasing M content x, and decreases following the order M = Co, Ni and with increasing x; in most of the samples studied, the ratio of crystallization temperature to melting point is about 2/3; when the alloy composition was varied ( <20at%-M) or an alloying transition element was added, Tcr increased linearly with decreasing average number outer electrons per atom which was calculaied by taking into account both the s,p and d electrons of the transition metal atoms. These results are discussed in connection with various factors such as composition, phase diagram, melting point, interatomic force and e/a effecting the stability of amorphous alloys.
REENTRANT BEHAVIOUR OF SPIN GLASS AND THE MAGNETIC PHASE DIAGRAM OF A SPINEL SYSTEM CoxZn1-x(Fey-Cr1-y)2O4
ZHOU WEN-SHENG, BIAN YAN
1990, 39 (9): 1494-1500. doi: 10.7498/aps.39.1494
Abstract +
A study of magnetic properties in the insuluing spinel system CoxZn1-x(FeyCr1-x2O4 has been made based on the temperature relationships of the low-frequency, weak field ac susceptibilities and low field magnetizations measurements. According to the above experimental results, we propose a probable magnetic phase diagram of the spinel. This magnetic phase diagram shows the reentrant spin glass phenomena in quite wide concentration ranges in the spinel. Increasing the concentration of the magnetic ions, the freezing temperatures of the reentrant spin glass increase. These properties are common in the systems with a few kinds of the magnetic ions or the magnetic ions which concentration are quite high. The mechanism of reentrance of spin glasses has been discussed in the paper. The reentrant spin glass in the spinel is a mixed state of spin glass and ferrimagnetic microdomains or spin clusters, which come from the collapse of the ferrimagnetic state.
THE ANOMALOUS DIFFRACTION OF A LASER BEAM IN LiNbO3:Fe CRYSTAL (Ⅰ)——e→ e DIFFRACTION
JIANG YI-JIAN, LIAO LI-JI, CHEN WEI-QUN, ZHANG PENG-XIANG, LIU YU-LONG
1990, 39 (9): 1501-1510. doi: 10.7498/aps.39.1501
Abstract +
Based on the anisotropic diffraction theory of phase gratings of Stepanov et al., using the method developed by Gu and Li, we have made a detail calculation of the effect of anomalous diffraction of a laser beam passing through a cube of LiNbO3: Fe crystal. Fourier transform of the chaotic destribution of electric charge excessively accumalated in small regions shows the existence of infinite number of phase gratings. The diffraction pattern is determined by the diffraction efficiency of these gratings. The results of calculation show that the two lobes on both sides of the central spot the shapes of which are determined by the lease effect can be interpreted. Theory and experimental data fit fairly well.
THE ANOMALOUS DIFFRACTION OF A LASER BEAM IN LiNbO3:Fe CRYSTAL (Ⅱ)——o→e DIFFRACTION
LIAO LI-JI, CHEN WEI-QUN, LIU YAN, JIANG YI-JIAN, ZHANG PENG-XIANG, LIU YU-LONG
1990, 39 (9): 1511-1519. doi: 10.7498/aps.39.1511
Abstract +
Some experimental facts concerning the anomalous diffraction pattern which arises when a laser beam o ray passes through a LiNbO3: Fe crystal with diffracted e ray and related phenomena in the Raman spectra are described. And the same method as was used in ref. [1] is applied to calculate the diffraction pattern quantitatively. Result of the calculations fits the experiment fairly well, this manifests the applicability of the theory of anisotropic diffraction of volume phase gratings to the anomalous diffraction with a 90° rotation of the polarization of the beams. Many other experimental facts are interpreted as well.
THE REFLECTION OF H+, D+ AND T+ FROM SURFACE OF SOLIDS
LUO ZHENG-MING
1990, 39 (9): 1520-1530. doi: 10.7498/aps.39.1520
Abstract +
In the present paper, the reflection coefficients of H+, D+ and T+ of various energies from surface of solids have been calculated by means of the recently-developed bipartition theory of light ion transport. A comparison of the results with relevant experiments and the Monte-Carlo results shows a good agreement. These results also show that the bipartition theory of light ion transport is an effective theoretical method for investigation of ion reflection from surface of solids.