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Vol. 32, No. 5 (1983)

1983-03-05
CONTENT
WAVES AND STABILITY IN THE BELOUSOV-ZHABOTINSKY REACTION SYSTEM
ZHENG JIU-REN, HUO YU-PING
1983, 32 (5): 571-581. doi: 10.7498/aps.32.571
Abstract +
On the basis of the Oregonator model, we took the rate constant k6, the stoichio-metric coefficient f and the wave number k as the parameters to study the stability of the BZ reaction system. The expressions of the following physical quantities were obtained, they included: the critical rate constant k6c of the space periodic structure, its short-wavelength critical wave number ksc and long-wavelength critical wave number kLc; the critical rate constant k6c of time-space periodic structure and its critical wave number kc(kc = kLc). Then we worked out the critical frequency λc of BZ reaction system and analyzed the near-by critical state behavior of the system, whereby we obtained the trigger wave velocity ur and phave wave velocity up. We came to the conclusion that, under certain conditions, the near-by critical state of unstirred BZ reaction system may exhibit a stable wave group, or, a wave packet.. The trigger wave is a wave packet in the homogeneous system and the phase wave is a wave packet in the inhomogeneous one with a slight gradient. We have got that (uT=2ηDkc, where D is the diffusion coefficient of HBrO2,η changes slowly with [H+] (to the extent of experimental observation, η≈ 0.1), and UP = v, where v is the phase velocity.
ELLIPTIC INCLUSIONS WITH LINEAR EIGEN STRAINS
ZHANG HONG-TU, ZHAO XIAO-PENG
1983, 32 (5): 582-592. doi: 10.7498/aps.32.582
Abstract +
If the eigen strains εij* of an elliptic inclusion are linear functions of position, the constraint strains εijc in the inclusion will also be linear functions of position. In this paper, all the constraint coefficients of first order are given. For the case β《1, the analytical expressions of stress fields outside the inclusion are found. The results can be used directly to practical problems, such as that of the behavior of a crack under bending stresses and the interaction between a plate-form inclusion and a micro-crack.
A THEORY ON THE 1/f NOISE IN METALS
YU MING-KANG, LIU FU-SUI
1983, 32 (5): 593-606. doi: 10.7498/aps.32.593
Abstract +
In this paper, we suggest a new physical mechanism for the in 1/f noise metals phenomena, which have a history of experimental observation for more than forty years. We propose that the 1/f noise is caused by the diffusion transportation with infrared divergence of the local electrons in metals. Based on the general theory of the low-frenquency fluctuation, dissipation and relaxation, a non-Markovian diffusion equation is established. The noise spectra deduced from this equation can explain the four basic characteristics of the 1/f noise. With reasonable choice of parameters, our noise spectra agree fairly well with experimental results. Some further discussions concerning the current theory and related problems are also given.
THE STATISTICAL THEORY OF CHEMICAL REACTIONS
HUO YU-PING, HU XI-WEI
1983, 32 (5): 599-570. doi: 10.7498/aps.32.599
Abstract +
In this article, a quantum statistical theory of fluctuation in chemical reaction systems has been developed. Starting from the Liouville equation, the equation for characteristic function and distribution function of density fluctuation has been obtained by projection operator method. The results confirm our previous phenomeno-logical theory. Finally, the correction terms of statistical theory and its influences on spectrum of fluctuation waves has been discussed.
THE LONGITUDINAL CRITICAL CURRENT OF A THIN FILM OF TYPE II SUPERCONDUCTORS
WU HANG-SHENG, GU YI-MING
1983, 32 (5): 607-617. doi: 10.7498/aps.32.607
Abstract +
The structure of the mixed state of a current-carrying thin film of ideal type II superconductors in longitudinal magnetic field He is analysed. We show that the lossless current flow through the films in the mixed state is possible only if He is larger than Hc1)(d). The curves of longitudinal critical current obtained have complex structure and show peak effect in general. The main feature of the theoretical Ic-He curve of the films with thickness d larger than 5λ is identical with that observed by Heaton and Rose-Innes in Nb55Ta45 alloys.
THE FORM FACTOR OF RADIATION SCATTERING IN AN ANISOTROPIC PLASMA
JIN YONG, LU QUAN-KANG, CHEN GUO-RANG, WANG QIAN, XIONG XlAO-MING, TANG MING
1983, 32 (5): 618-626. doi: 10.7498/aps.32.618
Abstract +
In this paper, the pair density correlation functions in a multicomponent aniso-tropic plasma are derived by BBGKY hierarchy. The form factors of radiation scattering in a bi-maxwellian plasma are obtained.
THE MODULATION INSTABILITY AND THE COLLAPSE PROCESS OF WAVE PACKET IN PLASMA
HE XIAN-SHI
1983, 32 (5): 627-639. doi: 10.7498/aps.32.627
Abstract +
In this paper, the expressions of the high-frequency and low-frequency nonlinear currents that leads to strong turbulence formation in plasma were found by using Kinetic theory. According to the system of equations in the reference [2] which included pondermotive force, self-generated magnetic field and their damping effects, we generalized the modulation instability analysis given by Kono et al. and obtained the expressions of growth rate parameter etc. in various cases while the longitudinal and transverse waves were excited by Langmuir or transverse pump waves. Finally, we discussed the collapse dynamics of wave packet and extended the collapse argument on nonlinear Schrodinger equation to the case of the density and field coupling equation system.
CHARGE TRANSFER AT In-Si (111) INTERFACE AND SURFACE ELECTROMIGRATION OF INDIUM ADATOMS
ZHOU JUN-MING
1983, 32 (5): 640-647. doi: 10.7498/aps.32.640
Abstract +
For the first time, we found by EHEED that a part of indium adatoms on the Si(lll) surface transports easily under the influence of an applied dc electric field. According to the observation of the surface electromigration process, it is shown that the states of adsorption of indium atoms on a clean Si (111) surface can be characterized as two phases - the first interface layer bound to silicon surface tightly is hardly affected by a electric field, it is called the tightly bound layer; overlayers on the first layer bound to the first interface layer loosely, can transport along the direction of an applied electric field, they are called transport layers. From the temperature dependence of the transport mobility, we find that the activation energy of surface electromigration is △H = 0.43 eV.The charge transfer in the process of In-Si(111) interface formation has been investigated by measurements of the surface conductance. The results show that indium atom is adsorbed as surface deep donor. Surface electromigration is attributed to Coulomb force applied on the ionized indium atom.
THE MAIN REFLECTED WAVE FIELD OF THE COHERENT LIGHT FROM SURFACES WITH SMALL CRATERS AND PARTICLES
CHENG LU, LIU ZHI-GUO
1983, 32 (5): 648-656. doi: 10.7498/aps.32.648
Abstract +
The general expression of the expectation of the main reflected wave field of the coherent light from surfaces with randomly distributed small craters and particles is deduced with a statistical model called "randomly random walk". Curves are computed for the case of normal probability density distribution.
BRIEF REPORT
THE NONEQUIVALENCE OF x-AXIS AND y-AXIS FOR RAMAN SPECTRA OF UNIAXIAL CRYSTALS
LIU SI-MIN, ZHANG GUANG-YIN
1983, 32 (5): 657-663. doi: 10.7498/aps.32.657
Abstract +
In this paper, we show that in Raman spectrum of uniaxial crystals, for nonpolar mode and A(z) (or B(z)) mode, under any scattering geometry, x-axis and y-axis are always equivalent. For polar mode E(x) and E(y), in the tetragonal and hexagonal crystal systems, x-axis and y-axis are equivalent in most cases; but in the trigonal crystal system, they are equivalent only in a few cases.
POISSON RATIOS OF FCC CRYSTALS
REN SHANG-YUAN
1983, 32 (5): 664-669. doi: 10.7498/aps.32.664
Abstract +
By using a simple physical model, we explain the reason why the Poisson ratio v110 in fcc crystals is negative. The theoretical relationship between the values of Poisson ratio v110 and v110 is indicated. The theory agrees with experimental results fairly well.
MEASUREMENT OF THE ENERGY SPECTRUM IN THE 3S1 POSITRONIUM 3γ DECAY
ZHANG TIAN-BAO, LI YAO-QING, TANG XIAO-WEI, WANG SHO-JIE
1983, 32 (5): 670-674. doi: 10.7498/aps.32.670
Abstract +
Using a high purity Ge spectrometer with time selection, we have measured the continuous γ ray energy spectrum from the 3S1 positronium 3γ decay in the 300-510 keV energy region. The result is in agreement within the experimental error with the quantum electrodynamic theoretical calculation.
CRYSTAL STRUCTURE OF POTASSIUM LANTHANUM METAPHOSPHATE
LIN YONG-HUA, HU NING-HAI, ZHOU QING-LIAN, LIU SHU-ZHEN
1983, 32 (5): 675-680. doi: 10.7498/aps.32.675
Abstract +
The crystal of potassium lanthanum metaphosphate with composition KLa[PO3]4 belongs to monoclinic system. The space gr oup is P21 with lattice parameters α= 8.106(3)?, b= 8.551 (2)?, c = 7.326(3)?, β = 92.18(6)°. Two molecules are contained in the unit cell. A fullmatrix, least square refinement gave R=0.061, Rw = 0.062 for 1026 independent reflections. The basic structural units are helical ribbons, (PO3)n, formed by cornersharing tetrahedra of PO4. The LaO8 dodecahedra are isolated without sharing any O atom with each other, and K atom locate on the center of irregular interstitial polyhedra. The shorhest La-La distance is 7.063?.
THE CALCULATION OF CRITICAL TEMPERATURE FOR Nb-Cu MULTILAYER FILM SUPERCONDUCTOR
CAI XUE-YU, YIN DAO-LE
1983, 32 (5): 681-684. doi: 10.7498/aps.32.681
Abstract +
The calculation of critical temperature for Nb-Cu multilayer film superconductor without any adjustable parameter shows that as the periodic character of multilayer film is considered, the theory of proximity effect agrees reasonably with experiment within the range of layer thickness d>30?.It is also shown that there exists damped oscillation in the dependence of critical temperature Tcns on d, the electronic structure of interface between Nb and Cu has obvious influence upon Tcns only when d<30? and the strong heterogeneous interface probably increases the (NV) of Nb.
OBSERVATION ON “AS GROWN” MICRODEFECTS IN CZ SILICON SINGLE CRYSTAL
LIN RU-GAN, ZHANG JIN-FU, MAI ZHEN-HONG, CUI SHU-FAN, FU QUAN-GUI
1983, 32 (5): 685-688. doi: 10.7498/aps.32.685
Abstract +
Two different type of microdefects have been observed by means of Cu-decorating X-ray topography and etching method in p-type silicon single crystal grown along and/or n-type ones grown along direction. A kind of defects with special configuration has also been found in n-type silicon single crystal. The distribution and configuration of these defects are discussed preliminarily.It was the first time to investigate the "as grown" microdefects in silicon single crystal grown by Czochraski method directly by means of X-ray transmission projection and/or section topography. X-ray topographs of microdefects in CZ silicon crystal were obtained. The configuration, size and distribution of the microdefects observed were in agreement with that obtained by Cu-decorating X-ray topography quite well.