Search

Article

x

Vol. 40, No. 6 (1991)

1991-03-20
GENERAL
GRAVITATIONAL AND CONFORMAL GAUGE THEORY IN INTEGRABLE WEYL SPACE
ZHAO SHU-CHENG
1991, 40 (6): 849-856. doi: 10.7498/aps.40.849
Abstract +
The conformal gauge field theory in the integrable Weyl spacetime is proposed. Based on this, a formula of the inertial mass field, m = kΦ(x), is obtained. The meaning of k is shown to be the gravitational charge and Φ(x) the inertial factor. By use of the geometrical characteristics of Weyl salar Φ(x), the conformal symmetry is shown to be broken spontaneously and the Eistein gravity emerged. The theory predict the existence of Weyl vector meson, which is massive and can not interact with any other matter fields.
ATOMIC AND MOLECULAR PHYSICS
X-RAY PHOTOELECTRON SPECTROSCOPY STUDY OF Fe ION IMPLANTED POLYCRYSTALLINE Al2O3
LI SHI-PU, FAN DONG-HUI, WANG GUO-MEI, XING NING, REN WEI
1991, 40 (6): 857-861. doi: 10.7498/aps.40.857
Abstract +
In this paper, all ionic states in the polycrystalline Al2O3 implanted with Fe ions are studied by X-ray photoelectron spectroscopy. The Gaussian decomposition of spectra is done by computer, and the relative content of various valence of implanted Fe ion is obtained.
OPTICAL ABSORPTION OF THE PYRAZINE-BRIDGED MIXED-VALENCE DIMER
PENG JING-CUI
1991, 40 (6): 862-869. doi: 10.7498/aps.40.862
Abstract +
A many-mode model which contains the intra-structure of pyrazine ring is presented and applied to the Creutz-Taube ion, a pyrazi ne-bridged mixed-valence compound of ruth-enium. In C-T ion, two Ru4dxz obitals are coupled with one π* obital on the pyrazine bridged ligand. They form linear combination which we lable as bonding (B), nonbonding (N), and antibonding (A) combination. Three many-dimensional potential surfaces are constructed. And the optical absorptions are considered as corresponding to transition between related potential surfaces. The results are more close to experimental data.
FORMATION OF Zn2 EXCIMER AND ITS EMISSION BEHAVIOR
CHENG BING-YING, LI ZHAO-LIN, YANG YONG-WU, NIE QING-XIANG, ZHANG DAO-ZHONG
1991, 40 (6): 870-877. doi: 10.7498/aps.40.870
Abstract +
Two emission bands of Zn2 excimers have been observed in mixture of Zn vapor and buffer gases by optically pumping Zn (4s1S0—4p3P1) resonance line. Expe rimental evidence shows that they are possibly from the same 3∑u+ upper state of Zn2 excimer, this coincides with theoretical prediction. Their temporal and temperature behaviors, and also the effect of buffer gases were studied. The upper limits of molecular formation and quenching rate were determined separately. The rescults indicate that the buffer gases dominate the molecular formation and decay process.
LASER-INDUCED FLUORESCENCE EXCIATION SPECTRUM OF OXALYL CHLORIDE
LU QING-ZHENG, CHEN YANG, TANG SONG-BAI, MA XING-XIAO
1991, 40 (6): 878-884. doi: 10.7498/aps.40.878
Abstract +
Laser-induced fluorescence excitation spectrum of oxalyl cholride (C2O2Cl2) in the rang of 358-372.5nm has been observed. More than 60 vibrational transitions have been assigned, in which 24 bands were not found in absorption spectrum. From the vibrational structure, we obtained some of the vibrational frequencies in ground state and excited state in which v"7=84cm-1 and v'7= 164cm-1 are new data. The rotational analysis of high resolved 401 band leads to the rotational constants A = 0.190cm-1, B = 0.114cm-1, and C = 0.048cm-1.
LASER-INDUCED FLUORESCENCE EXCITATION SPECTRUM OF CCl2 COOLED IN THE SUPERSONIC JET
CHEN YANG, LU QING-ZHENG, WANG DONG-QING, SHEN LIU-SI, WANG HONG-FEI, ZHANG YUN-WU, YU SHU-QIN, MA XING-XIAO
1991, 40 (6): 885-890. doi: 10.7498/aps.40.885
Abstract +
Laser-induced fluorescence excitaion spectrum of gas-phase dichlocarbene (CC12) cooled in the supersonic jet has been observed in the range of 497-517 nm. The K-structrue of the (v1,v2,0)-(0,0,0) vibrational bands was resolved. About 80 su-bbands were assigned. v'1= 643.5cm-1, v'2 = 308.0cm-1 and the anharmonic costants, and (A'-B') = 3.67cm-1, (A" - B") = 1.80cm-1 were obtained from the analysis of spectra.
VUV RADIATION IN COLLISIONS BETWEEN Ar+ AND ATOMS
PAN GUANG-YAN, LEI ZI-MING, YANG FENG, LU XIAO-LIN, LIU CAN-WEN, LIU JIA-RUI, SUN XIANG
1991, 40 (6): 891-896. doi: 10.7498/aps.40.891
Abstract +
The VUV emission spectra have been absolutely measured in collisions between Ar+ and He, Ne, Xe by using LHT-30 Monochromator. The ionization excitation processes of incident ions and target atoms have been observed. The "promotion" of electron of molecular orbit model of Fano and Lichten, and adiabatic MO correlation diagram have been introduced. We have made attempt to work out some qualitative explanation.
COMPARISON OF IONIZATION CROSS-SECTION FORMULAS WITH EXPERIMENTS IN MICROANALYSIS
TANG TAO, WU ZI-QIN, ZHANG SHU-YUAN
1991, 40 (6): 897-903. doi: 10.7498/aps.40.897
Abstract +
Characteristic X-ray intensity ratios of M and L lines I(M)/I(L) from a series of pure elements were measured in the analytical electron microscope at 75-200kV. Compiling the previous measured ratios together, all the data have been compared with the calculated values from eight cross-section formulas after normalization in order to eliminate the uncertain parameters, leaving only the voltage dependence of the cross-section. These formulas can be divided into four groups for I(L)/I(K) or three groups for I(M)/I(L) ratios. Only one group, containing two formulas suggested by Fabre de la Ripelle and Schreiber and Wims, is in good agreement with all the experimental data.
CLASSICAL AREA OF PHENOMENOLOGY
SQUEEZING OF THE SQUARE OF THE FIELD AMPLITUDE IN TWO-PHOTON ABSORPTION PROCESS
HE LIN-SHENG
1991, 40 (6): 904-911. doi: 10.7498/aps.40.904
Abstract +
From the master equation of the field density for the two-photon process, with the help of the generation function method, the expressions of the squeezing of the square of the field amplitude generated in two-photon absorption process are derived. The variations of the square of the field amplitude with the dimensionless time τ, the phase θ and the average number of photons of the incident field are discussed. It is shown that the two-photon absorption process is an effective way generating the squeezing effect of the square amplitude of the field. Finally, the independence of the amplitude-squared squeezing effect is demonstrated.
GENERATION OF PHOTON-NUMBER SQUEEZED STATE BY OPTICALLY PUMPED THREE-LEVEL ATOMIC SYSTEM
GUO GUANG-CAN, CHAI JIN-HUA
1991, 40 (6): 912-922. doi: 10.7498/aps.40.912
Abstract +
In this paper, we show that the photon-number squeezed state can be generated by optically pumped three-level atomic system. The Fano factor of the output radiation field has been calculated under the condition of incoherent pumping, weak coherent pumping and strong coherent pumping respectively. We find that the optimum squeezing effect of photon-number occurs in the situation of weak coherent pumping and the corresponding Fano factor is 0.16. This method of generating photon-number squeezed state is convenient and practical in experiment.
A STUDY ON THE OPTICAL NONLINEARITY OF SOME NEW TYPES OF KERR MEDIA
LIU SI-MIN, KANG MIN-JIAN, ZHANG GUANG-YIN, WU YUAN-QING, XU JING-JUN
1991, 40 (6): 923-925. doi: 10.7498/aps.40.923
Abstract +
We have restudied the optical nonlinearity of the solutions of Chinese tea in ethyl alcohol or water using z-scanning method. The study shows that the optical nonlinearity only depends on the laser-heating-induced negitive lens effect in the media.
INJECTED PARAMETRIC OSCILLATION IN LITHIUM VAPOR
ZHU BAO-QIANG, ZOU YING-HUA, XIA ZONG-JU
1991, 40 (6): 926-934. doi: 10.7498/aps.40.926
Abstract +
The injected 2s-3d two-photon resonant parametric oscillation in lithium vapor has been studied theoretically and experimentally. It's output, compared with general pamametric oscillation, has better monochromaticity and appears as a "sharper" conical radiation. Furthermore, the injected parametric oscillation is tunnable as we change the frequency of the seed beam on the red side of the 2s-2p transition of lithium atom.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
ANALYTIC SOLUTION OF HYDROMAGNETIC FLOW DUE TO A ROTATING DISK AND CALCULATION OF EFFECTIVE SEGREGATION COEFFICIENT Keff OF SOLUTE IN SILICON MELT
YANG SHU-LIN, MAI ZHEN-HONG, MAO ZAI-XIAN
1991, 40 (6): 935-942. doi: 10.7498/aps.40.935
Abstract +
Based on the analytic solution of hydromagnetic flow due to a rotrating disk, both velocity field and effective segregation coefficient Keff of solute in silicon melt in terms of one dimensional model were calculated under actions of various axial magnetic field strength. Results of computer simulation are presented graphically. It is found that not only the magnitudes of velocity components are strongly suppressed by magnetic field, but also the Keff of solute increases as the magnetic field increases with given rotational rate, finally tends to a constant within some definite regions of magnetic field. In addition, it is also found that the Keff is strongly dependent on the diffusion coefficient of solute.
EVOLUTION OF HYDROGEN (DEUTERIUM) IN PALLADUIM HYDROGEN (DEUTERIUM) SYSTEM AND THE DISTRIBUTION OF HYDROGEN NEAR THE SURFACE
PENG QING-ZHI, FU JI-SHI, ZHANG LI-ZHU, ZHANG BO-RUI, QIN GUO-GANG
1991, 40 (6): 943-948. doi: 10.7498/aps.40.943
Abstract +
Hydrogen and deulerium have been introduced into palladuim cathods in an electrolysis process for 150 h with light and heavy water as electrolyte respectively. The palladuim cathods used had quenched or annealed after a thermal treatment at 950℃. The variation of diffraction pattern and lattice constant of β phase of palladuim-hydrogen system in air with time have been measured by X ray diffraction method. The distribution of hydrogen in the surface layer of palladuim-hydrogen system bas been measured by the nuclear reaction1H(19F,αγ)16O. Comparing a quenched palladuim cathod with annealed palladuim cathod, it is shown that the former has higher initial concentration of hydrogen and faster evolution velocity than the latter after the electrolysis. The concentration of hydrogen arrives its maximum at the surface of palladuim hydrogen system and its minimum at a depth of several hundred angstroms from the surface.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
ON THE CORRESPONDENCE OF BAND EIGENSTATES OF (GaAs)1(AlAs)1(001) SUPERLATTICE AND Ga0.5Al0.5As ALLOY
WANG REN-ZHI, HUANG MEI-CHUN
1991, 40 (6): 949-956. doi: 10.7498/aps.40.949
Abstract +
Based on the LMTO-ASA numerical calculations, we contrast the band eigensrates of the (GaAs)1(AlAs)1(001) superlatrice with those of the zincblende Ga0.5Al0.5As alloy. We find that they can be described unifiedly by the partial-wave states of the III and V group atomic planes. In this scheme, we analyze in more detial the correspondence relations of the band eigenstates of superlattice and zincblende alloy at Γ, M(X), and R(L) points. The effects of the superlattice zone folding on the eigenstates are also discussed.
ELECTRON CORRELATION AND SOLITON
SUN XIN, XIE SHI-JIE, MEI LIANG-MO
1991, 40 (6): 957-961. doi: 10.7498/aps.40.957
Abstract +
The electron correlation and soliton in polyacetylene have been studied with the CBF method. By considering the complete electron-electron interaction, we concluded that the stable static configuration of a PA chain with odd atoms and a single electric charge is a soliton. With the increase of e-e interaction strength U and interaction range α/β the localization of soliton is enhanced, and the soliton creation energy is reduced, so although the e-e interaction is considered, the conclusion that soliton is main charged carrier in high conducting polymers is still tenable.
RAMAN SCATTERING STUDIES OF MBE-GROWN GaAs/Si
HU FU-YI, LI AI-ZHEN
1991, 40 (6): 962-968. doi: 10.7498/aps.40.962
Abstract +
The origin, profiling and interaction of biaxial compressive and tensile stresses in unan-nealed MBE grown GaAs/Si along the growth direction for thickness range of 500?-4.2μm has been studied by Raman Scattering Spectroscopy measurement. The shift asymmetry of the LO phonon peak was investigated in detail.
STUDY OF AlGaAs/GaAs WAVEGUIDE STRUCTURE BY X-RAY DOUBLE CRYSTAL DIFFRACTION
MAI ZHEN-HONG, GUI SHU-FAN, WANG CHAO-YING, WU LAN-SHENG
1991, 40 (6): 969-977. doi: 10.7498/aps.40.969
Abstract +
An AlGaAs/GaAs waveguide structure sample was investigated by X-ray double crystal diffraction technique. Based on the X-ray dynamical diffraction theory the reflection intensities of the substrate and the films were calculated. Comparing the calculated results with the experimental ones, the real structure of the sample was obtained. The factors affecting the double crystal diffraction recking curves are discussed.
ANALYSIS OF CORRECTION FACTOR FOR SAMPLES' LENGTHS IN MEASUREMENT OF DC MAGNETIZATION
WANG YU-GUI, YUAN SONG-LIU, WANG SHUN-XI, XIONG XIAO-ZHONG, YANG YU
1991, 40 (6): 978-984. doi: 10.7498/aps.40.978
Abstract +
In this paper, we analysed the diamagnetization flux of samples with different lengths by calculating the distribution of the magnetic field produced by magnetization current. A simple and clear correction factor which was determined by the coil size and samples' lengths was obtained. An accurate calculation method for absolute magnetization of samples with small cross section was presented. Through the measurement of the susceptibility on BiPbSrCaCuO superconductors with different lengths, this method is shown to be valid.
TIME DEPENDENT CRITICAL CURRENT AT ZERO FIELD FOR SINTERED Tl2Ba2Ca2Cu3Oy SUPERCONDUCTOR
DING SHI-YING, SHI KE-XIN, ZENG CHAO-YANG, YU ZHENG, SHI ZHI-XIANG, QIU LI
1991, 40 (6): 985-989. doi: 10.7498/aps.40.985
Abstract +
A new method determining the distribution of flux pinning energy U0, is described. The method is mainly the measurement of time dependent zero field critical current for sintered high temperature superconductor magnetized in applied field. By means of this method, the U0 distribution of Tl2Ba2Ca2Cu3Oy at 78K is obtained. Based on the experimental result, the dispersion of reported U0 is discussed.
LOW TEMPERATURE STABLE PHASES OF HIGH Tc SUPERCONDUCTOR YBa2Cu3Oz
WANG QIANG, ZHANG XIAO-WEN, GU BING-LIN, TANG XIAO-FENG
1991, 40 (6): 990-997. doi: 10.7498/aps.40.990
Abstract +
Based on eight-point cluster variation method and introduction of isotropic nearest neighbor interaction and anisotropic next nearest neighbor interactions, the orderdisorder phase transition phenomena of the □-O (□: oxygen vacancy; O: oxygen) system on the copper-oxygen plane between two Ba-layers were studied. Calculation results show that there is not only a superconducting orthohombic phase (I) near z = 7.0, but also a superconducting orthohombic phase (II) near z = 6.5, as well as other metastable phases.
MAGNETIC AND M?SSBAUER SPECTRA STUDY OF YTi(Fe1-xCox)11
KONG LIN-SHU, YANG YING-CHANG
1991, 40 (6): 998-1004. doi: 10.7498/aps.40.998
Abstract +
YTi(Fe1-xCox)11 crystallizes in the ThMn12-type tetragonal structure, with x ranging from 0.0 to 1.0, the Curie temperature increases with the increase of Co content. In order to understand the relation between magnetic properties and microst-ructure of these compounds, we studied their M?ssbauer spectra. The M?ssbauer effect measurements were carried out at room temperature on YTi(Fe1-xCox)11, with x equal to 0.0, 0.2 and 0.4. The best fits confirm that Co atoms preferentially occupy the j and f sites. The hyperfine fields of the measured samples reach a maximum at x = 0.2,which is in agreement with the results of magnetic measurements. By comparing the experimental results of M?ssbauer spectra of YTi(Fe1-xCox)11, Y2(Fe1-xCox)14B and YTi(Fe1-xNix)11, we analyze the difference of the 3d band structure between YTiFe11, and Y2Fe14B.
A THEORETICAL STUDY ON THE MAGNETIC FIELD OF A RECORDING HEAD WITH ARBITRARY POLE-ANGLE
YAO XUE-BIAO
1991, 40 (6): 1005-1010. doi: 10.7498/aps.40.1005
Abstract +
In this paper, the distribution of the magnetic field of a recording head with arbitrary pole-angle in the vicinity of the head's air gap is studied by the method of Schwartz-Christ-offel transformation. The theoretical formulas are real, and the numerical values of the distribution of the field are obtained. Some applications are also discussed.
ELECTRON SPIN RESONANCE INVESTIGATION OF Eu2+ IN BaCl2
SHI CHAO-SHU, HAN SHI-YING, HOU BI-HUT, LU XIAO-PU, XIA SHANG-DA
1991, 40 (6): 1011-1016. doi: 10.7498/aps.40.1011
Abstract +
The ESR spectra of BaCl2: Eu powder showed that Eu2+ ion substituting the ion Ba2+ is situated in a crystal field of the orthorhcmbic symmetry. By fitting the ESR experimental data to the axial symmetric spin Hamiltonian and the crystal field Hamiltonian, the spin Hamiltonian parameters were obtained. In addition, based on variation of ESR peak-hight versus doping concentration of Eu, the doping value Cs for saturated substitution of Eu2+ was found to be 0.34 mol%.
EFFECT OF THE PERPENDICULAR PUMPING CONFIGURATIONS ON THE SECOND-ORDER SPIN-WAVE INSTABILITY THRESHOLD IN SINGLE CRYSTAL YIG FILMS
CHEN MING, ZHANG YOU-TING
1991, 40 (6): 1017-1024. doi: 10.7498/aps.40.1017
Abstract +
This paper is to further discuss the second-order spin-wave instability processes for the ferrite sample of ellipsoidal shape using Schl?mann and Patton methods. The theoretical expressions of the second-order spin-wave instability threshold for film samples are different from Anderson-Suhl formula. The threshold calculations for single crystal YIG films under three different perpendicular pumping configurations show that the calculated thresholds are reasonably consistent with the experimental results for three configurations, and the threshold values given theoretically and experimentally are in close relationship with the oreintation of the linearly polarized microwave magnetic field.