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Vol. 36, No. 7 (1987)

1987-04-05
CONTENT
THE ROUGHNESS OF THE Si-SiO2 INTERFACE
HONG GUO-GUANG, HUANG BING-ZHONG, YU YU-ZHEN
1987, 36 (7): 829-837. doi: 10.7498/aps.36.829
Abstract +
The roughness at the Si-SiO2 interface has been determined by the ellipsometric spectroscopy. Several geometric forms have been used to simulate the surface irregularities. The dielectric properties of the rough layer are modelled in the effective-medium approximation by dividing the rough layer into a number of sub-layers with equal thickness. The asperity height H (normal to surface) and the correlation length L (along the surface) can be defined by best fit of the theoretically calculated multiphase reflective ellipsometric parameters ψcal, △cal to the measured ellipsometric parameters ψexp, △exp. It is found that the trend of the electric properties of the sample is consistent with the variance of its roughness. It is also found that the dielectric function of Si has some anisotropic properties at the interface.
A RESEARCH FOR THE ENTIRE BREAKDOWN PROCEDURE IN THIN DIELECTRIC FILMS
CHEN DOU-NAN
1987, 36 (7): 838-846. doi: 10.7498/aps.36.838
Abstract +
A new model used to interpret the phenomena of dielectric breakdown is proposed over the whole range of applied field. There are two main mechanisms that one of which is the avalanche breakdown, so-call intrinsic type, and the other is the filament heating transport leading to the destructive breakdown exist in the breakdown process. The theoretical analysis and the experimental data indicate that the field strength of intrinsic breakdown depends on the band gap and the thickness of film, but the filament heating transport which induces a destructive breakdown depends on the properties of film. In particular, the defect is the main origin leading to the occurrence of destructive breakdown. In addition, the effect of various physical parameters, testing conditions and process factors on the breakdown are discussed briefly.
A PHENOMENOLOGICAL THEORY OF INTERFACE DYNAMICS IN THE PROCESS OF DIFFUSIONLESS PHASE TRANSFORMATION AND ITS APPLICATIONS
ZHANG JIN-XIU, LI XIE-JUN
1987, 36 (7): 847-854. doi: 10.7498/aps.36.847
Abstract +
The relationship between average velocity of phase and/or domain interface V and the effective phase transformation (PT) driving force in the process of diffusionless (DL) PT △G' (the difference between PT driving force AG and the resistence △GR, △G'=△G - △GR) can be expressed as V = φ(△G - △GR). Consider a monodirectional varying external field (intensity is ξ and varying rate is ξ) exerted on a DLPT system, the phase interface moves and then the DLPT takes place when △G provided by the external field increases to a critical value △GR. If a hamonic external stress σ = σ0 sin ωt which can interact with the moving interface exerts on the system and the coupling factor is n,an expression between dynamic relation of interface V = φ(△G - △GR) and the internal friction in the DLPT process Q-1, related modulus defect △M/M, PT rate dF/dξ and the PT strain ε0 can be derived as d lnφ(△G')/d△G'= Q-1ω/n2M(dF/dξ) = (△M/M)ω/nMε0(dF/dξ)ξ, or and (△M/M)Q-1=ε0/n. where ω is frequency of hamonic stress, M is modulus related to vibration mode. A gerenal solution of the interface dynamic equation can be obtained as V = ∑(±n)/(α≠-1) Aα exp[((△G - △GR)/△Gα*)α+1/(α+ 1)] +∑(m)/(β0) Aβ(△G-△GR)/△Gβ*)β where Aα,Aβare coefficient, △Gα* and △Gβ* are resistance parameters related to the high velocity interface. The specific solution and the value of △GR can be determined by the experimental data of the internal friction in the DLPT with diffrent ξ. The equation of (△M/M )/Q-1 can be used to determine whether the soft mode contributes in the process of DLPT.
A STUDY OF CREEP RUPTURE IN COPPER BY MEASUREMENTS OF INTERNAL FRICTION
KONG QING-PING, DAI YONG
1987, 36 (7): 855-861. doi: 10.7498/aps.36.855
Abstract +
On the basis of our previous work [1] on commercially pure aluminum, the change of internal friction peak of grain bound- (Ke peak) in commercially pure copper has been studied in the course of creep. Creep experiments were conducted under different conditions: (a) high temperature and low stress; (b) medium temperature and medium stress; (c) low temperature and high stress; which lead to intergranular, mixed type and transcrystalline rupture respective'y. From the changes of grain boundary peak under different creep conditions, it can be deduced that the strength of grain boundaries is changed little during creep at high temperature and low stress; somewhat increased at medium temperature and medium stress; and considerably increased at low temperature and high stress. The present work indicates that the strength of grain boundaries is changeable during creep. The extent of strengthening of grain boundaries is different under different creep conditions, which is believed to be an important roie to lead to different type of creep rupture. This provides a modification and complement of the idea of "equicohesive temperature".
EFFECT OF La (OR MISCHMETAL Mm) ON THE HYDROGEN STORAGE CHARACTERISTICS OF TiFe
LIANG JING-KUI, RAO GUANG-HUI
1987, 36 (7): 862-869. doi: 10.7498/aps.36.862
Abstract +
The hydrogen storage capacities and pressure-composition isotherms of TiFe + La and TiFe + Mm alloys were measured by exhausting water method. The effect of La and Mm on the activation characteristics of the alloys was studied. It was shown that the activation characteristics of the alloys could be improved greatly and the alloys were activated near the room temperature when the quantities of La or Mm in the alloys were greater than 4 wt% under our experimental conditions. However, La or Mm did not enter the crystal lattice of TiFe. They presented in the alloys in the form of a second phase to purify the alloys. The hydrogen storage mechanism mainly depends upon the intermetallic compound TiFe. The formation enthalpies of the hypothetical hydrides TiFeLayH1.0, were also calculated after Miedema's formulae and compared with the experimental results.
DISPERSION RELATION OF GENERAL MAGNETICALLY CONFINED WEAK RELATIVISTIC PLASMAS
GUO SHI-CHONG, CAI SHI-DONG
1987, 36 (7): 870-880. doi: 10.7498/aps.36.870
Abstract +
The dispersion relation for weak relativistic inhomogeneous plasma in general magnetic field configurations is derived from the relativistic gyrokinetic equations, which is valid for arbitrary frequencies. In the derivations the singular integrations with the quadratic denominator are represented by the drift plasma dispertion functions. This dispersion relation can be used to study the various micro instabilities driven by gradient and curvature of B, weak relativistic effects, and/or gyrofrequency shift. Extending the results to the nonequilibrium case such as loss-cone distribution is simple and straight forward. For demonstration, we apply it to investigate the lower hybrid drift instability. Using this dispersion relation we can recover the re-suits of Drake et al. in a straight forward and much more transparent way.
RADIAL RESONANT ELECTRON FLOW DRIVEN BY LOWER-HYBRID WAVES
XIA MENG-FEN, WU WEI-MIN
1987, 36 (7): 881-891. doi: 10.7498/aps.36.881
Abstract +
In lower-hybrid current drive Tokamak, the waves can drive radial resonant electron flow, which is composed of an average flow and a diffusion flow. The characteristics and the effects of the radial flow are discussed.
A NEW APPROACH TO INVESTIGATING THE VALENCE FLUCTUATION COMPOUNDS
ZHENG HANG
1987, 36 (7): 892-901. doi: 10.7498/aps.36.892
Abstract +
The ground state properties of the Sm-based valence fluctuation compounds are discussed by introducing an indirect on-site hybridization mediated by phonons, as the direct on-site hybridization is forbidden by inversion symmetry. The Hamihonian including this indirect hybridization is transformed into an effective Hamihonian of a "small polaron" type by means of a. canonical transformation. A self-consistent field approximation is used, a non-zero energy gap and the noninteger occupation of the f level have been given. The results obtained can be used to explain the small energy gap and the valence fluctuation phenomena observed in SmB6 and SmS.
STUDY ON THE MICROSTRUCTURE OF AMORPHOUS ALLOYS TM80M20 BY MSSBAUER SPECTROSCOPY
M. GHAFARY, U. GONSER, XU YU-SHENG
1987, 36 (7): 902-908. doi: 10.7498/aps.36.902
Abstract +
The Mossbauer spectra of amorphous alloys Fe80B20-xMx (M = P, C) at room temperature and 4.2 K have been measured. It is found that the mean values of the hyperfine field and the isomer shift vary linearly when M (P, C) substitutes for B. Two structure models of amorphous alloys, microcrystal model and Bernal-Polk model, have been compared using these results and that of their crystalline counterparts. The study suggests that there do not exist a microcrystalline short range order and corresponding transition in amorphous alloys TM-M as in the crystalline counterparts. For describing the microstructure of amorphous alloys TM-M the Bernal-Polk model is preferable to the microcrystal model.
NEW BEHAVIORS OF BIFURCATION AND CHAOS IN A NONLINEAR OPTICAL RING CAVITY
ZHAO YONG, HUO YU-PING
1987, 36 (7): 909-914. doi: 10.7498/aps.36.909
Abstract +
In this paper, lkeda equation for a nonlinear optical ring cavity is studied by numerical method. It is found that the topological structure, the way of bifurcation and its convergence rate and the period-window-structure depend on the parameters B and φ0 in long delay time limit. In short delay time limit, some anomalous period-windows and nonperiod-doubling bifurcations are revealed, and it is also discovered that the self-similar structure in chaotic bands is blurred in the short time limit.
THE HEAVY-FERMION BEHAVIOR IN THE RARE-EARTH AND ACTINIDE COMPOUNDS
CHEN CHANG-FENG, ZHANG LI-YUAN
1987, 36 (7): 915-923. doi: 10.7498/aps.36.915
Abstract +
In this paper, the periodic Anderson Hamiltonian has been used to study the heavy-fermion behavior in the Rare-Earth and Actinide compounds. The mean-field approximation has been applied to the Coulomb correlation term between the f electrons and a self-energy term has been introduced to represent the effect of the many-body interaction. The single-site approximation has been used for the self-energy term. The properties of the systems have been discussed in a quasi-particle picture. The effective mass of the quasi-particles has been obtained through the self-consistent calculation of the average occupation number of the f electrons. The conditions necessary for the presence of the heavy fermions and the corresponding change of the magnetic properties have been discussed and numerical computation has been carried out. The calculated results have been compared with recent experiments.
THE EFFECT OF ANNEALING ON THE PROPERTIES OF AMORPHOUS GERMANIUM/CRYSTALLINE SILVER BILAYER
LIU HONG-BAO, WANG JI-HONG, WANG CHANG-SUI, XUE BAI, ZHANG YU-HENG
1987, 36 (7): 924-929. doi: 10.7498/aps.36.924
Abstract +
By using X-ray differaction, SEM and the measurement of sheet resistance, the effect of annealing of a-Ge/c-Ag bilayer were studied. Sheet resistance of the bilayers were measured in the range 80-300 K. The relation between sheet resistance at room temperature and annealing temperature was presented. A new diffusion mechanism was found. As the temperature increased, amorphous germanium crystallize. In the meantime, a part of Ge diffuse into Ag. When the temperature went on increasing, the germanium which diffused into silver would separate out again. The activation energy of diffusion was estimated to be 0.15 eV by means of measuring the sheet resistance of bilayer.
THE OPTICAL PHONONS, PLASMON AND LO PHONON-PLASMON COUPLING MODE IN MIXED CRYSTAL GaAs1-xPx GROWN BY LIQUID PHASE EPITAXY
FANG ZHI-LIE, LAO PU-DONG, LU WEI, YE HONG-JUAN, TAO FENG-XIANG, SHEN XUE-CHU
1987, 36 (7): 965-973. doi: 10.7498/aps.36.965
Abstract +
The far infrared reflection spectra of n-GaAs1-xPx with x= 0.328 and x = 0.40 are investigated in the frequency range of 40-700 cm-1 and the temperature range of 4.2-300 K. The important physical parameters describing the optical phonons, plasmon and LO phononplasmon coupling mode of the material and infrared optical constants are obtained by the multioscilla-tor fitting and K-K relation calculation. A model of two conduction band valley with a donor level below and associated with X minimum is presented to explain the behavior of the dependence of plasmon frequency on temperature and the variation of the three coupling modes with temperature.
A STUDY ON THE CRITICAL CONDITION OF LASER RECRYSTALLIZATION FOR POLY-CRYSTALLINE SEMICONDUCTOR FILM ON INSULATING SUBSTRATE
LENG JING-MING, QIAN YOU-HUA, LIN CHENG-LU, FANG FANG
1987, 36 (7): 974-980. doi: 10.7498/aps.36.974
Abstract +
For poly-crystalline semiconductor film deposited on an insulator and then recrystallized by a laser beam, the influence of the substrate upon recrystallization of the film was analyzed theoretically. We found the critical laser power necessary for solid-liquid phase transition to take place, will change to a lower value as the poor thermal conduction of insulating substrate being reasonably considered. It is well known that the existence of stress in recrystallized films may be taken as a criterion for melting process that undergoes during laser irradiation. A large number of SOI samples prepared by LPCVD technology were studied after its laser recrystallization, to obtain the critical transition conditions through strass determination by use of Raman peak shifts. A comparison of the calculations based on the model taking low thermal conductance of the substrate into account with the experimental results showed its fitting is better than that with the influence of substrate being neglected.
BAND STRUCTURE OF RARE EARTH INTERMETALLIC COMPOUNDS CeSn3 AND CeIn3
YE LING, HUANG MEI-CHUN, ZHU ZI-ZHONG
1987, 36 (7): 981-985. doi: 10.7498/aps.36.981
Abstract +
The electronic energy band structures of CeSn3 and Celn3 are studied with LMTO-ASA method. The behavior of the f-electrons of Ce and the hybridization between f-orbitals and the s, p, d orbitals of non-f-atoms are discussed. The density of states and energy bands are investigated, especially in the vicinity of EF.
A STUDY ON AS-GROWN SWIRL DEFECTS IN CZ SILICON CRYSTAL
DUAN PEI, GAO PING, TANG JI-YOU
1987, 36 (7): 986-991. doi: 10.7498/aps.36.986
Abstract +
The oxide precipitates (1000-6000 ?) were separated from as-grown CZ silicon crystal containing the swirl defects by means of chemical etching method. The selected-area electron diffraction analysis of the precipitates, which had been prepareted into the extraction replica specimens, was carred out in TEM. Simultaneously, the morphology of the swirl defects in silicon thin foil specimens was observed with TEM. Thereby, the corresponding relation between the particles in the extraction replicas and the swirl defects in the silicon thin foils was established. It was concluded that a great number of the swirl defects are keatite (silica k) in the form of sguare-shaped platelets with {100} habit planes and sides in parallel with 〈ll0〉 direction, and a small part of the swirl defects are a-cristobalite in the form of hexagon-shaped platelets with {111} habit planes and sides in parallel with 〈ll0〉. IR absorption spectra of as-grown CZ silicon samples showed that the square plate-shaped keatite were probably associated with the absorptior band at 1224cm-1.
PARAMETER CHOICE FOR A LASER BEAT-WAVE ACCELERATOR
YU WEI, XU ZHI-ZHAN
1987, 36 (7): 992-997. doi: 10.7498/aps.36.992
Abstract +
The three-wave interaction in a laser beat-wave accelerator are studied. We find that with the parameters of σ = ωp(ω1-ω2) and β=ω2/ω1 properly chosen (where ωp, ω1, ω2 are the plasma frequency and frequencies of the two laser beams respectively), the required large-amplitude plasma wave will be excited even though the incident laser beams are relatively weak. As a result, the injected electrons will get a sighificant energy gain.
WAVE FUNCTIONS FOR AND OSCILLATOR STRENGTHS BETWEEN HIGH RYDBERG STATES OF Na ATOM
ZHANG XUE-RONG, LI BAI-WEN, CHEN AI-QIU, ZHANG CHENG-XIU
1987, 36 (7): 998-1003. doi: 10.7498/aps.36.998
Abstract +
The phenomenological atomic potential model with analytical solutions is employed to obtain the wave functions of the Rydberg states (10≤n≤40) and the oscillator strengths of the ns-n'p, np-n'd and nd-n'f transitions between them. The results are very close to those obtained by the CA method. These results show that there exists a kind of scaling law for the above oscillator strengths.
DISAPPEARANCE AND REAPPEARANCE OF THE (001) REFLECTIONS OF MONTMORILLONITE
ZHU BIN, WANG DA-ZHI, ZHOU GUI-EN, YU WEN-HAI
1987, 36 (7): 1004-1009. doi: 10.7498/aps.36.1004
Abstract +
Montmorillonite samples treated at different temperatures had been studied by XRD. The (001) reflections of some samples disappeared, and reappeared under some conditions. The crystallographic significance and the possible phase transformation had been discussed.
BOUNDARY COUPLING EFFECTS OF LATTICE VIBRATION IN ACOUSTIC BRANCH
LI JING-DE
1987, 36 (7): 1010-1018. doi: 10.7498/aps.36.1010
Abstract +
Taking account of two- and three-body interaction of the nearestneighbours, the acoustic modes of N×N square lattice is solved in harmonic approximation. The boundary coupling effect leads to physical pictures of phonons different from those in infinite lattice. The standing wave phonons can only be classified according to space species, and the wave vector losses it's sense. Numerical computation shows that the strengthening of the covalent property leads to appearence of a boundary coupling soft mode. The modes related to rotation, inner-rotation, C/I structure, and surface wave phonon are also given. The phonon spectrum of finite lattice extends to the lower and higher end. The effects in three dimensions are also considered.
APPLICATION OF AN EXACT DECIMATION TRANSFORMATION WITH MEAN-FIELD APPROXIMATION METHOD TO THE POTTS MODEL
YE QING, TANG KUN-FA, HU JIA-ZHEN
1987, 36 (7): 1019-1026. doi: 10.7498/aps.36.1019
Abstract +
In this paper, the critical exponents of the Potts model are calculated by using the exact decimation with mean-field approximation method. The results obtained are in good agreement with that of the exact calculation. The accurary of this method is better than other renor-malisation group methods.
EFFECTS OF LINE-TYING ON HOT ELECTRON INTERCHANGE MODE
HUANG CHAO-SONG, REN ZHAO-XING, QIU LI-JIAN
1987, 36 (7): 1027-1032. doi: 10.7498/aps.36.1027
Abstract +
The effects of cold plasma and conducting end plates on interchange instability of finite-length hot electron plasma are studied. A dispersion relation including line-tying is derived, and new stability criteria are found. Strong line-tying effect can greatly reduce the threshold of densky ratio needed for stabilizing interchange mode of hot electrons. The modes with low m and long wavelength may be stabilized more easily.
THE INTERACTION BETWEEN NEAR NEIGHBORING ATOMS IN METGLAS Fe80B20 AND Fe80Si6B14
WANG WEN-CAI, CHEN YU
1987, 36 (7): 1033-1040. doi: 10.7498/aps.36.1033
Abstract +
The X-ray K absorption spectra of iron in metglas Fe80B20 and Fe80Si6B14 are measured, using the rotating anode X-ray generator and the EXAFS spectrometer with bend crystal. The structural parameters of near neighbor of these metglases are determined by EXAFS. Besides, their XANES are also measured. While comparing the XANES of iron in metglases with that in α-Fe, FeB and Fe2B, we discovered some changes on the energies of their absorption edge and the characters of "white line". These show that there is stronger interaction between near neighboring atoms Fe-B, Fe-Si and Fe-Fe in metglases than that in the stable compounds of iron and boron. And this has an important effect on the shortrange order structure of these metglases.
HALL EFFECTS AND SUPERCONDUCTIVITY OF ANORPHOUS InSb AND ITS METASTABLE INTERMEDIATE PHASES IN THE PROCESS OF THE CRYSTALLIZATION PHASE TRANSITION
ZHANG YU-HENG, CAO XIAO-WEN, ZHAO DIAN-FENG
1987, 36 (7): 1041-1047. doi: 10.7498/aps.36.1041
Abstract +
Hall effects of amorphous InSb and its metastable intermediate phases which appear in the process of the crystallization phase transition have been studied. Experimental results show that the conduction of the electron is dominative in the metal-type amorphous InSb and the conduction of the hole is dominative in the semiconductor-type amorphous InSb. The first jump of the conductance is a process of the structure relaxation from the liquid-like amorphous state to the lattice-like one; the third jump of the conductance was caused by In-Sb solid solution with the rich In or rich Sb which was separated out and segregated on the grain boundaries. The three types of the crystallization phase transition of the metal-type amorphous InSb present obviously different transportion hehaviours. The rise of superconducting Tc of the metastable crystalline metallic phase which corresponds to the peak of the second jump of the conductance originates possibly from the increase of the electron concentration.
BRIEF REPORT
A NEW METHOD TO GENERATE THE SOLUTIONS OF THE REDUCED EINSTEIN EQUATIONS
HOU BO-YU, LI WEI
1987, 36 (7): 930-934. doi: 10.7498/aps.36.930
Abstract +
In this paper, we present a new transformation in the solution space of the Ernst equation and investigat the relationship between the solutions of the Ernst equation and our transformation. We show that the Ernst equation is invariant under such a transformation, i.e., our transformation can be used to generate the new solutions of the Ernst equation from the old ones. Finally, we discuss the relationship between the Virasoro algebra and this transformation.
QUANTIZED MOTION OF TWO-DIMENSIONAL ELECTRONS IN A STRONG MAGNETIC FIELD
XIONG XIAO-MING, ZHOU SHI-XUN
1987, 36 (7): 935-939. doi: 10.7498/aps.36.935
Abstract +
In the symmetric gauge with vector potential the one-body wave functions of two-dimen sional electron in a strong magnetic field have been obtained analytically. Based on the diseussing of two non-interacting electrons, we get a relation of the wave functions in two representations. This relation is useful in considering the interactions between the electrons.
THE CHARACTERIZATION OF FLUX PINNING FORCE FOR Nb3Sn SUPERCONDUCTING MATERIALS IN HIGH MAGNETIC FIELDS
ZHOU LIAN, CUI CHANG-GENG, CAO ZHONG-SHENG
1987, 36 (7): 940-944. doi: 10.7498/aps.36.940
Abstract +
Expenrimental results of Jc(B) in high magnetic fields for diffusion and CVD Nb3Sn tapes and MF Nb3Sn wires have been analysed by using regression analysis, the empirical rules for Jc(B) and FP(B) in high magnetic fields were obtained. The rules are different from Kramer scaling law. There is a need for a new model of flux pinning mechanism to explain the empirical rules.
THE PLANAR HALL EFFECT AND THE MAGNETORESISTANCE EFFECT IN THE AMORPHOUS SOFT MAGNETIC FILM Fe90-xCoxZr10
ZHANG WEN-XING, CHENG XIAN-AN, WANG XV-WEI, WANG YIN-JUN
1987, 36 (7): 945-950. doi: 10.7498/aps.36.945
Abstract +
In this work, the dependence of the planar Hall votage and the magnetoresistance on composition, temperature, and the applied magnetic field has been studied. All the measurements were made by the six probe method. From the results, the planar Hall votage and the magnetoresistance are shown to satisfy the phenomenological formula simultaneously: Vy = p0M2sin2θ and △ρ = cM2cos2θ, and we obtain an equation Vy = cρ2M2sin2θ. Morever, the change of the planar Hall votage of Co90Zr10 and Fe70 Co20Zr10 after their crystallization are just opposite, that is, the above-mentioned value of the Co-rich one increases, but that of the later one decreases.
MEASUREMENTS OF THE WHOLE SET OF THE ELASTIC AND PIEZOELECTRIC PARAMETERS OF THE SINGLE CRYSTALS Fe:LiNbO3 AND Cr:LiNbO3 BY BRILLOUIN SCATTERING OF LIGHT
JIANG ZUI-MIN, LIU YU-LONG, ZHANG PENG-XIANG
1987, 36 (7): 951-955. doi: 10.7498/aps.36.951
Abstract +
Brillouin scattering of light from certain crystal plane of polished single crystal spheres was measured. From the obtained data of sound velocity anisotropy, all the elastic and piezoelectric parameters of the single crystals of Fe and Cr doped LiNbO3 were deduced. The results were compared with pure LiNbO3. Discussion indicated that the sign uncertainty of some elements of the elastic tensor was due to the choice of the coordinates.
[Al-O-P] GROUPS IN Na2O- Al2O3-P2O5 GLASSES
JIN YI-FEN, CHEN XIANG-SHENG, HUANG XI-HUAI
1987, 36 (7): 956-959. doi: 10.7498/aps.36.956
Abstract +
In this paper, we present the Raman spectra of [Al-O-P]- groups in Na2O-Al2O3-P2O5 glasses. We attribut the regular shift of high frequency peak in the Raman spectra to the decrease in the glass network polymerization.
THE MEASUREMENTS OF HARD X-RAY FLUCTUATIONS IN THE HT-6B TOKAMAK
WANG ZHENG-MIN, LI LIN-ZHONG
1987, 36 (7): 960-964. doi: 10.7498/aps.36.960
Abstract +
Nal(Tl) scintillation detector and Si(Au) surface barrier semiconductor detector are used to measure X-ray fluctuations in the HT-6B Tokamak device. The hard X-ray emission and sawtooth oscillations have been observed. The experiment shows hard X-ray fluctuations are due to MHD disturbances in the frequency range of 2-25 kHz.
A PHENOMENOLOGICAL MODEL FOR 0- MESON (Ⅰ)
ZHANG ZHENG-GANG, WU ZI-YU, LAN HUI-BIU, WANG KE-LIN, LIU YAO-YANG, XIAN DING-CHANG
1987, 36 (7): 1048-1055. doi: 10.7498/aps.36.1048
Abstract +
By use of the spinor-spinor Bethe-Salpeter equation of field theory, we assumed a phenome-nological "flat bottom" hadronic potential which is relativistically covariant. And the meson wave functions was obtained in the momentum space.
EQUAL TIME KAC-MOODY ALGEBRA FOR GENERAL TWO DIMENSIONAL NON-LINEAR σ MODEL
WANG XIAO-LIN, DAI YUAN-BEN
1987, 36 (7): 1056-1059. doi: 10.7498/aps.36.1056
Abstract +
It is shown that for general compact simple Lie groups and arbitrary value of coupling constant λ0, the equal time current algebra of the two dimensional non-linear σ model with Wess-Zumino term is a Kac-Moody algebra with center charge.
THE DOUBLE CURIE TEMPERATURE PHENOMENON OF NbNi AMORPHOUS ALLOYS
CHEN ZHAO-JIA, WU BAI-MEI, LIU YAN-ZHANG, LIU ZHI-YI
1987, 36 (7): 1060-1063. doi: 10.7498/aps.36.1060
Abstract +
In the amorphous alloys Nb1-xNix (x = 0.564, 0.598, 0.65), we observed the double Curie temperature phenomenon of itinerant electron magnetism and also the typical susceptibility cusp for spin glass freezing. In this alloy system, both itinerant electron magnetism and localized magnetic moments appear very clearly.
ON ULTRAVIOLET-VISIBLE ELLIPOMETRIC SPECTRA OF As+ IMPLANTED SILICON
JIANG REN-RONG, XIANG SONG-GUANG, WANG HAO-WEN, XU ZE-HONG, MO DANG
1987, 36 (7): 1064-1069. doi: 10.7498/aps.36.1064
Abstract +
The radiation damage and the annealing behaviour of 1×1016-3×1012/cm2 As+ implanted silicon have been measured with a TPP-1 spectroscopic ellipsometer. The results are as follows: (1) The amorphous layers were formed on the surface of Si samples when the doses of implanted As+ were higher than the critical value. In the case of the doses were smaller than the critical value, both the n-λ and the ε2-λ curves for As+ implanted silicon shifted downward with an increase dose of implanted As+. (2) With annealing at 700℃, the n-λ curve and ε2-λ curve in the spectra range of 4000-7000 ? of As+ implanted silicon exhibited the behavious of single crystalline silicon. However in the range of 2700-4000 ?, the curves did not show crytalline silicon behaviour and the difference between these curves and those taken with cryslline silicon increased with the doses of implanted As+. (3) The dose dependence of the radiantion damage has been obtained.
HYDROGEN ADSORPTION ON GaAs AND InP (111), (111) SURFACES STUDIED BY HREELS
HOU XIAO-YUAN, YANG SHU, DONG GUO-SHENG, DING XUN-MIN, WANG XUN
1987, 36 (7): 1070-1074. doi: 10.7498/aps.36.1070
Abstract +
The hydrogen adsorption on GaAs and InP surfaces was studied by high resolution electron energy loss spectroscopy (HREELS). The stretching vibration modes of Ga-H, As-H, In-H and P-H bonds corresponding to different energy loss peaks in the spectra were all observed. However, the As-H vibration mode was usually confused with Ga-H "phonon echo" peak which is the Ga-H vibration mode plus an optical surface phonon loss. The identifying of As-H from the "phonon echo" peak could be done only by comparing the relative intensities of the loss peaks. The experimental HREELS show that the bonding between the adsorbed hydrogen and the surface atoms was determined largely by the surface atomic structure and electron distribution. For the GaAs (111) surface, only surface Ga atoms form bonds with the hydrogen under low exposure, while at high exposure both As-H and Ga-H bonds could be formed. On InP(lll) surface which was treated by annealing under phosphorus pressure, in addition to the In-H bond the P-H bond was formed even at low exposure. Only P-H loss peak could be seen on InP(lll), which suggested that such surface was fully terminated with P atoms. In the case of forming facets on (111) surface, both surface group Ⅲ and group V atoms could from bonds with hydrogen.
STUDIES ON UPS AND XPS OF O2 AND H2O ABSORPTION ON SURFACES OF SrTiO3
CHEN YUN-QI, LIN ZHANG-DA, QI SHANG-XUE, XIE KAN, CHANG YING-CHUAN, HOU DE-SEN, WANG TAI-HONG
1987, 36 (7): 1075-1080. doi: 10.7498/aps.36.1075
Abstract +
The presence of surface state originated from Ti3+ ion on reductive SrTiO3 surface has been observed. The action of Ti3+ on photodecomposition of water and the action of light irradiation on regeneration of activity are analysed.
BIREFRINGENCE IMAGES OF END-ON SCREW DISLOCATIONS IN GGG CRYSTALS CONTAINING A LONG-RANGE PLANE STRAIN FIELD
GE CHUAN-ZHEN, FENG DUAN, ZHANG JING
1987, 36 (7): 1081-1086. doi: 10.7498/aps.36.1081
Abstract +
The expression for intensity distribution and computer simulated images of screw dislocations with Burgers vector 1/2〈1ll〉viewed end-on in gernet crystals subjected to a long-range strain have been obtained by considering only the anisotropy of the photo-elastic property of the material. The computer-simulated images of end-on screw dislocations show twofold symmetry with a pair of dark and bright petals which result from the effect of a longe-range plane strain field superimposed on screw dislocation. The computer-simulated images are in good agreement with the experimental images in GGG crystals.
INTERPRETATION OF THE CONDUCTANCE OF AMORPHOUS SUPERIONICS BASED ON THE THEORY OF LOW-FREQUENCY FLUCTUATION, DISSIPATION AND RELAXATION
DING YI, WU KUN-YU, YU WEN-HAI
1987, 36 (7): 1087-1092. doi: 10.7498/aps.36.1087
Abstract +
Based on the characteristics of superionic glasses and a physical picture of unified theory of the low-frequency fluctuation, dissipation and relaxation phenomenon, the transport features of a non-Markovian process of conduct ions are explored. The theory predict that the frequency independent conductance follows a simple Arrhenius type dependence on temperature at high temperatures. The theory can also explain the frequency dispersion of the conductance at low temperatures, and the degree of the frequency dispersion depends on the infrared divergence exponent n.
SHIFT OF THE CENTER OF GRAVITY OF RARE EARTH ION IN THE CRYSTALS
ZHANG SI-YUAN
1987, 36 (7): 1093-1098. doi: 10.7498/aps.36.1093
Abstract +
In this paper, the influence of crystal field on the shift of center of gravity of rare earth ion are discussed theoretically. The shifts of the center of gravity of 4IJ state due to the J-mixing effect occur in 15 crystals doped Nd3+ are calculated. The results show that the splitting width of spectral term 2S+1L due to spin-orbit coupling is increased by J-mixing effect and it dependents on the composition and structure of the host.
ISOTHERMAL COMPRESSION OF α-LiIO3 AND ITS PHASE TRANSITION UNDER HIGH PRESSURE AND HIGH TEMPERATURE
HU JING-ZHU, CHEN LIANG-CHEN, WANG LI-JUN, TANG RU-MING, CHE RONG-ZHENG
1987, 36 (7): 1099-1104. doi: 10.7498/aps.36.1099
Abstract +
The volume compression of α-LiIO3 has been studied by X-ray diffraction in a diamond anvil cell up to 23.0 GPa at room temperature. The anisotropic compression of lattice was observed. The ratio of c/a of parameters decreased with a rate of -6.187×10-3/GPa with pressure. The bulk modulus of normal pressure and its first pressure deviative have been determined to be equal to 39.2 and 3.787 GPa respectively. At high pressure and high temperature, hexagonal α-LiIO3 transformed to a tetragonal phase. The structure was the same as quenching-releasing pressure phase, i.e., the ε phase.