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Vol. 45, No. 11 (1996)

1996-06-05
GENERAL
SOLITARY WAVE SOLUTIONS TO THE 2N+1 ORDER KdV-TYPE EQUATIONS
ZHU ZUO-NONG
1996, 45 (11): 1777-1781. doi: 10.7498/aps.45.1777
Abstract +
In this paper, explicit and exact solitary wave solutions to the 2N+1 order KdV-type equations are given. The higher order generalized KdV equation(GKdVE), the higher order generalized MKdV equation (GMKdVE), and the higher order generalized Schamel's MKdV equation(GSMKdVE) are covered by these equations. Moreover, 2N+1 order KP-type equation is discussed.
TWO KINDS OF DISLOCATION PATTERNS AND THE FORMING REASONS DURING THE PUSH-PULL FATIGUE PROCESS FOR Al SINGLE CRYSTALS
WANG JING, ZHU ZHEN-GANG, LIU GUO-DONG
1996, 45 (11): 1782-1787. doi: 10.7498/aps.45.1782
Abstract +
Variations of the stress σm and internal friction Q-1 versus cyclic number N under push-pull fatigue strain εt=6×10-4 for [100] Al single crystals were measured. The dislocation configuration at different stages of fatigue was observed by TEM. A elucidation was given with the view of dislocation slip geometry.
ATOMIC AND MOLECULAR PHYSICS
THE EXCITATION-AUTOIONIZATION OF Na-LIKE Cu ION
HU WEI, WANG YAN-SEN, FANG DU-FEI, TENG HUA-GUO, XU ZHI-ZHAN
1996, 45 (11): 1788-1792. doi: 10.7498/aps.45.1788
Abstract +
The excitation autoionization of Na-like Cu ion origination from inner-shell excitations of 1s22s22p63s→1s22s22p53s3l(l=0,1,2) was investigated in some detail. The inner-shell excitation cross sections were calculated in the distorted Columob-Born exchange approximation and the target ionic states were obtained in a single configuraton approximation. The autoionizing branch ratios were calculated by using both single configuration and configuration interaction wavefunctions. The results showed that, at an incident electron energy of 1090 eV, the correlation enhancement of excitation autoionization cross sections was mainly due to 1s22s22p53s3d configuration,in which the correlation effects increasd the excitation autoionization cross sections nearly to a factor of 2. The excitation autoionization cross sections for 1s22s22p53s2 were reduced about 36% when compared with the results of single configuration approximation. Howecer, The configuration interaction had only a slight effect on the autoionization cross sections for excitation to 1s22s22p53s3p configuration.
ARTIFACTS IN 2D NMR NOESY SPECTRA OF WATER DUE TO RADIATION DAMPING
GUO JIAN-XIN, MAO XI-AN
1996, 45 (11): 1793-1799. doi: 10.7498/aps.45.1793
Abstract +
Harmonic peaks appearing in ω1 dimension of the NOESY spectra on liquid water are sidcussed. The NOESY experiment is analuzed by using radiation damping line shape theory and the result shows that these harmonic peaks are artifacts induced by radiation damping. It is also shown that the line shapes of the artifacts are dependent on the mixing time,in good agreement with the experimental results. Some methods for eliminating these artifacts are proposed.
PHOTOIONIZATION STUDIES OF DIBROMOMETHANE USING SYNCHROTRON RADIATION: A STUDY OF VIBRATIONAL AUTOIONIZATION STATES FOR CH2Br2 IN 10-12eV
SHENG LIU-SI, ZHANG YUN-WU, LI QUAN-XIN, RAN QIN, CHEN CONG-XIANG, YU SHU-QIN, MA XING-XIAO
1996, 45 (11): 1800-1806. doi: 10.7498/aps.45.1800
Abstract +
The vibrational autoionization stucture of dibromomethane has been investigated in the supersonic beam conditions using VUV synchrotron radiation. Based on photoionization efficiency curve of CH2Br2+ in 105—123nm we have found that the adiabatic ionization potential(IP) of the dibromomethane is 10.23±0.01eV.The thresholds at 10.78±0.01eV,11.20±0.01eV and 11.27±0.01eV ware identified as the electronically excited states of CH2Br2+,i.e., A(2A2),B(2B1) and C(2A1) states. The discrete peaks with some autoionization features superposed on a step-like structure in the PIE curve of the parent ion were observed in the range of 115.01—121.15nm. The average step width was about 716.8±40.0cm-1,which was in good agreement with the value of the vibrational frequency of the Br-C-Br antisymmetrically stretching motion (v9) of the parent ion CH2Br2+(X2B2) which was measured by infrared absorption method. All strong peaks ware assigned to the autoionization, ns,np and nd Rydberg states converging to various vibrationally excited states of the ground state of CH2Br2+. In addition, the vibrational modes and autoionization structure occurring in the ground electronic state of the daughter ion CH2Br+(X)were also assigned.
CLASSICAL AREA OF PHENOMENOLOGY
EVEN AND ODD GENERALIZED COHERENT STATES IN THE NON HARMONIC OSCILLATOR POTENTIAL
XU ZI-WEN
1996, 45 (11): 1807-1811. doi: 10.7498/aps.45.1807
Abstract +
In this paper,the conception of even and odd coherent states is generalized to the nonharmonic oscillator potential. It is found that squeezing exists alternatively in the even and odd coherent states with the increase of the mean energy, and the squeezing of the quantum fluctuation of the natural coordinate in the time evolution has a period of π/2.
SEMICLASSICAL THEORY OF RAMAN FREE-ELECTRON LASERS
LI ZHI-KUAN
1996, 45 (11): 1812-1816. doi: 10.7498/aps.45.1812
Abstract +
In this paper, we point out that the problem of a system of many particles can be simplified into that of a single electron by using Thomas-Fermi potential in Raman free-electron lasers. Klein-Gordon equation is solved by using perturbation theory. The formula of the density of electric charge and current density are derived from the corresponding zero order wave function. If we simplify properly the Klein-Gordon equation, we can solved by using the methods of seperation of variables and WKB approximation. We also derived the formula of the electric charge and current density which correspond to the new wave function.
AN EXPERIMENTAL SIMULATION ON LARGE-SCALE HELITON
ZHAO SONG-NIAN, XIONG XIAO-YUN, ZHU JIANG
1996, 45 (11): 1817-1823. doi: 10.7498/aps.45.1817
Abstract +
Large-scale vortex motion, the typical example of which is typhoon in nature, has behaviour of soliton. This is proved by large-scale dynamical simulation experiment in the rotating annulus. Thus we suggest that one can adopt scientific term "Heliton"(i.e.,helical soliton) to characterize this motion pattern.
A STUDY ON THE PEIERLS TRANSITIONS OF BLUE BRONZE K0.3MoO3 SINGLE CRYSTAL
LIU ZHI-GUO, FENG DUAN, YIN JIANG, DOU AO-CHUAN
1996, 45 (11): 1824-1829. doi: 10.7498/aps.45.1824
Abstract +
K0.3MoO3 single crystals with the size of 2cm×1.5cm×1cm have been grown by electrolytic reduction of K2CO3-MoO3 melt with a K2CO3-to-MoO3 mole ratio of 1 to 4.32. The temperature dependence of normalized resistivity R(T)/R(290K)-T of a K0.3MoO3 single crystal has been determined. It is found that the semiconductor gap of the single crystal is 1320K(0.11eV). The threshold electric field ET is 0.129V/cm derived from the data of nonlinear conductivity at T=77K.DSC study of the samples shows that the K0.3MoO3 single crystal undertakes a new Peierls phase transition around 240K and that the phase transition is of first order. The Δcp-T curve shows that the phase transition around T=180K is a combination of a second order and a first.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
IMPROVING THE DIRECT METHOD FOR SOLVING SUPERSTRUCTURES
GU YUAN-XIN
1996, 45 (11): 1840-1845. doi: 10.7498/aps.45.1840
Abstract +
Direct methods have been proved to be effective and objective for solving superstructures. Two algorithms have been proposed to further improve the efficiency. The first was the same number of E's in all reflection groups. The second was a set of artificial E's in phase derivation to eliminate the effect from abnormal distribution of E values. The new algorithms have been incorporated into new version of SAPI.
DETERMINATION OF ANOMALOUS SCATTERING FACTOR FOR Ga BY USING ROCKING CURVES OF TRANSMITTED BEAM IN GaAs
ZHOU SHENG-MING, ZHAO ZONG-YAN, HAN JIA-HUA, HU YU-GEN, TETSUO NAKAJIMA, TOMOE FUKAMACHI, RIICHIROU NEGISHI, MASAMI YOSHIZAWA
1996, 45 (11): 1846-1851. doi: 10.7498/aps.45.1846
Abstract +
The diffracted and the transmitted rocking curves for GaAs(200) in the symmetric Laue case are observed near the Ga K-absorption edge by using the synchrotron radiation. The quantitative comparison between the measured transmitted rocking curves and the corresponding calculated ones based on the dynamical theory of X-ray diffraction has been cattied out, and the anomalous scattering factors for Ga K-absorption edge in GaAs have been determined.
ANALYSIS OF DEFECT STRUCTURE IN Mg-DOPED LiNbO3 CRYSTAL
LIU JIAN-JUN, ZHANG WAN-LIN, ZHANG GUANG-YIN
1996, 45 (11): 1852-1858. doi: 10.7498/aps.45.1852
Abstract +
According to the Li vacancy model of intrinsic defect in LiNbO3 the defect structures formed in LiNbO3:Mg with varying Mg contents are proposed. The Li2O,Nb2O5 contents [Li]/[Nb] ratio, in crystals and the densities of the crystals are calculated by using the defect models. The calculated calues are in good agreement with the experimental results.
THE DYNAMICALLY MECHANICAL PROPERTIES OF Zn-22%Al ALLOYS IN EUTECTOID DECOMPOSITION
LIU JUN-MIN, ZHANG JIN-XIU
1996, 45 (11): 1859-1864. doi: 10.7498/aps.45.1859
Abstract +
The mechanical properties of Zn-22% Al alloys were measured with the low-frequency forced vibration mode. It was observed that a typical transformation internal friction peak was associated with eutectoid decomposition. A relaxation peak in the complex elastic modulus M2-T curves with an activation energy of 100±1.2kJ/mol was observed at the low-temperature side of the eutectoid decomposition peak. It was deduced that the relaxation process was related to the diffusion process of Al atom along the α/β phase boundary and α/α crystal boundary.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
FERMI AND NON-FERMI LIQUID BEHAVIOR OF THE MULTICHANNEL RESONANT-LEVEL MODEL
YUAN QING-SHAN, CHEN HONG, ZHANG YU-MEI
1996, 45 (11): 1865-1874. doi: 10.7498/aps.45.1865
Abstract +
In this paper we have transformed the three-dimensional multichannel resonant-level model into one-dimensional model using ths s-wave scattering approximation, and then map it onto a single channel Kondo model at the operator level by use of a bosonization technique. The specific heat has been calculated and the Fermi and non-Fermi liquid behavior of the system have been discussed for two fixed point Hamiltonians.
SCATTERING-THEORETICAL METHOD FOR THE RECONSTRUCTED β-SiC(100) SURFACE
GUO QIAO-NENG, FAN XI-QING, ZHANG DE-XUAN, MA BING-XIAN
1996, 45 (11): 1875-1883. doi: 10.7498/aps.45.1875
Abstract +
By using scattering-theoretical method, we have calculated the surface-band structure of ideal and (2×1) reconstructed β-SiC(100) surface, and the lay-, atom-and orbital-resolved densities of states. The results show that the major effects of reconstruction occur in the band-gap energy region, and the reconstructed Si and C terminated surfaces are semiconducting. Our calculated surface-band structure are in good agreement with experiments. According to the bonding states and localized state densities of two dimerized atoms, the dimeric symmetry of Si atoms and the dimeric asymmetry of C atoms have qualitatively been explained.
THE ELECTRONIC STRUCTURE AND STRUCTURE STABILITY OF Ag(111) AND Ag(001) SURFACES
ZHANG HAI-FENG, LI YONG-PING, PAN BI-CAI
1996, 45 (11): 1884-1889. doi: 10.7498/aps.45.1884
Abstract +
By using the Linearized Muffin-Tin Orbital Method, the surface electronic structure of several "stable Ag(111) surfaces" obtained by different methods were systematically studied and contrasted, the different surface electronic character of the different relaxation surfaces were presented and discussed. According to the surface energy, the most stable Ag(111) surface was single layer inward relaxed surface, and the local electronic densities of states of this king of structure were presented and discussed. The local electronic dendities of states of ideal clean Ag(001) surface were also studied, and the results that the Ag(001) surface were also presented. the Ag(001) surface is more stable than Ag(111).
A THEORETICAL STUDY ON THE SURFACE ELECTRONIC STRUCTURES OF Si NANO-CLUSTERS
YE LING
1996, 45 (11): 1890-1897. doi: 10.7498/aps.45.1890
Abstract +
The electronic structures of H,O and OH chemisorbed on Si nano-clusters were calculated with local density functional formalism. Atomic force calculations were used to reach at an optimized chemisorption site for the adsorbates. Different models were used. For all H adsorbed clusters, wider energy gaps are opened up compared with that of bulk Si, and quantum size effect is obviously shown. When a shell of the adsorbed H atoms is replaced by oxygen atoms, oxygen induced tail states appear in the gap. Both occupied and unoccupied states exist, and the gap is reduced from that in all H-terminated cases. For O atoms replaced by OH, the tail states become all occupied, but the gap widths do not differ much. No quantum size effects are observable for both O and OH adsorption.
SRPES STUDY OF THE Sm/Si(100) INTERFACE FORMATION AND ELECTRONIC STRUCTURES
LU ER-DONG, YU XIAO-JIANG, PAN HAI-BIN, ZHANG FA-PEI, XU PENG-SHOU, XU SHI-HONG
1996, 45 (11): 1898-1904. doi: 10.7498/aps.45.1898
Abstract +
The behavior of interface formed by growing this Sm film on the Si(100)2×1 substrate at room temperature has been investigated by cove level and valence band photoemission using synchrotron radiation. The experimental results show the existence of distinct stages corresponding to chemisorption and agglomeration of Sm atoms(coverage Θ<0.5ML),reactive interdiffusion (0.5ML≤Θ≤4—6ML), and growth of metallic Sm. Compared to Si(111)7×7 the reactivity of Sm on the Si(100)2×1 substrate is enhanced and a greater tendency for interdiffusion of Sm and Si is observed. Also we have discussed the interface formation and the interface profile carefully.
ELECTRIC BREAKDOWN OF PERCOLATION SYSTEM OF 2D METAL FILM ON FULLERENE UNDERLAYER
GU ZHEN-NAN, ZHOU XI-HUANG, JIN ZHAO-XIA, WU KE, WU JUN-QIAO, WANG ZHI-JUN, ZHANG JIN-LONG, LI CHUAN-YI, YIN DAO-LE
1996, 45 (11): 1905-1912. doi: 10.7498/aps.45.1905
Abstract +
Fullerene (C60 and C70)films were epitaxially grown on fresh (001) mica fcc closely-packed plane parallel to the substrate surface. Metal-overlayers were deposited onto these fullerene films in an ultra-hight-vacuum(UHV) chamber and in situ resistance measurements were performed. With increasing current, we observed reversible resistance variation and irreversible breakdown. Nera the percolation threshold we find power law scaling behavior Ib~R-α,where Ib is breakdown current and R the sample resistance. The exponent α is much smaller than the values given by previous experiments and prediction of conventional Nodes-Links-Blobs(NLB) model. Possible explanation of these phenomena based on metal-fullerene interfacial interactions is discussed.
A COMBINATION MODEL OF SUPERCONDUCTIVITY UNDER s+d MIXED WAVE SYMMETRY
SUN JIU-XUN, ZHANG LI-YUAN
1996, 45 (11): 1913-1920. doi: 10.7498/aps.45.1913
Abstract +
Under the symmetry of the s+d mixed waves, a model is proposed which accounts for the combined influence of two factors on superconductivity. The first factor is the anisotropy of the pairing interaction between electrons, and the second is the Van Hove singularity in the two dimensional electronic structure. The theoretical results show that both the Van Hove singularity and the pairing interaction anisotropy are important factors to enhance Tc. The anisotropic pairing interaction naturally leads to the d-wave component. As this anisotropy strengthens, the d-wave component increases. The fairly high ratio of 2Δ(0)/kBTc of the high-Tc superconductors may be due to the fact that the weight of the s-wave component is far smaller than the weight of the d-wave component. The specific heat jump at Tc in combination model is completely different from the classical BCS theory.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
NUMERICAL SIMULATIONS OF LARGE SCALE EQUATORIAL SPREAD F
M.C.KELLEY, HUANG CHAO-SONG
1996, 45 (11): 1930-1839. doi: 10.7498/aps.45.1930
Abstract +
We have performed numerical simulations of nonlinear evolution of plasma interchange instability in equatorial spread F(ESF) under different conditions. It is shown that the interchange instability resulting from one-or two-dimensional initial density perturbations can grow into plasma bubbles but cannot evolve into the plumelike structures on the west wall of a plasma bubble .The production of plasma bubbles initiated by gravity waves takes a much shorter time than that resulting from two-dimensional density perturbations. When both a gravity wave and a smaller scale initial density perturbation are used,it is found that the large scale gravity wave determines the outer scale of ESF irregularities and the smaller scale perturbation results in the plumelike structures preferentially located on the west wall. The numerical results show a good agreement with observations.