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Vol. 30, No. 12 (1981)

1981-06-20
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CONTENT
7Li NMR INVESTIGATIONS IN LiCl WITH DSPP
WANG GANG, LI ZI-RONG, CHEN LI-QUAN, ZHAO ZONG-YUAN
1981, 30 (12): 1569-1575. doi: 10.7498/aps.30.1569
Abstract +
In order to understand the mechanism of the ionic conduetivity enhancement in LiCl (or LiI) containing dispersed second-phase particles (DSPP), we have performed 7Li NMR investigations on both line width and spin-lattice relaxation time (T1) at 35 MHz in temperature range of 173-483 K. An additional peak was observed to overlap the resonance absorption line. The signal-to-noise ratio was obviously increased while T1 decreased. The profile of this peak changes with type and content of DSPP and temperature. It is concluded that the ionic eonductivity enhancement and the appearing of the additional peak are both given rise by the DSPP of submicron size. The high conduction in the space charge region near the interface between LiCl and DSPP is suggested as a possible mechanism for the ionic conductivity enhancement and the appearing of the additional peak.
DIELECTRIC PROPERTIES OF THE IONIC CONDUCTOR SINGLE CRYSTALS UNDER THE ACTION OF A DC FIELD
XU ZHENG-YI, ZHU YONG, ZHANG DAO-FAN, LI CHEN-XI
1981, 30 (12): 1576-1581. doi: 10.7498/aps.30.1576
Abstract +
In our previous works, it had been found the apparent dielectric constant ∈c′ of α-LiIO3 single crystal increases as a bias DC field is applied in the c direction. And it had been attributed to result of ionic conduction. In this paper, the dielectric properties of KLiSO4 and NaCl single crystals under the action of a DC field have been investigated. Similar to the situation of α-LiIO3 single crystal, the phenomenon of change of the apparent dielectric constant was observed in these crystals. It verified the conclusion mentioned above. We also studied the dependences of this property of ionic conductors on temperatures, frequencies and ambient atmosphere. The condition under which this phenomenon appeares was discussed.
ARTIFICIAL PHASE DEGENERATION IN THE DETERMINATION OF NON-CENTROSYMMETRIC STRUCTURES
FAN HAI-FU, GU YUAN-XIN, XU ZHANG-BAO
1981, 30 (12): 1582-1585. doi: 10.7498/aps.30.1582
Abstract +
During the phase derivation in the case of non-centrosymmetric crystal structure, if one forces the phases to degenerate into a set of signs corresponding to those of the real parts of structure factors, it then results in an E-map containing simultaneously the actual structure and its enantiomorph. Such an E-map may in turn easily be retrieved by use of the component relation leading to a unique solution of the structure. With this procedure only two possible values (0 or π) are necessary to be considered for each unknown phase within the starting set. Hence the amount of calculation can be greatly reduced as compared with that of the ordinary phase permutation method.
CRYSTAL STRUCTURE OF DIMETHYL SULPHOXIDE COMPLEX OF EUROPIUM
LIN YONG-HUA, HU NING-HAI, LIU SHU-ZHEN, ZHOU QING-LIAN, WU SHI-XUE, WANG MING-YI, SHI EN-DONG
1981, 30 (12): 1586-1590. doi: 10.7498/aps.30.1586
Abstract +
The crystal of dimethyl sulphoxide complex of europium Eu (NO3)3·4DMSO belongs to the monoclinic system. The space group is C2/c-C62h. The cnystal parameters are a = 14.806 (9)?, b = 10.948 (3)?, c = 15.335 (4)? and β= 108.07 (7) °. Four molecules are contained in a unit cell, z = 4. The diffraction data have been collected by using PW-1100 four-circle diffractometer, the total number of independent diffractions amounts to 2270. The structure was solved by heavy-atom method, and structure parameters have been refined by means of full-matrix and block-diagonal least square method, R = 0.069. The europium ion in this structure is found to be coordinated by ten oxygen atoms. The distances between the europium and the coordinating oxygens are Eu-ODMSO=2.38?, Eu-O(NO3)=2.61?.
COLLISIONAL AND INHOMOGENEOUS BROADENING EFFECTS IN GAS-FLOW AND CHEMICAL LASERS——THE THEORETICAL MODELS
GAO ZHI
1981, 30 (12): 1591-1602. doi: 10.7498/aps.30.1591
Abstract +
The analytical models which are used to predict the performance of gas-flow and chemical lasers are enumerated and compared. These analytical models include the currently accepted theory of Lorentz-Gauss line shape factor, the present theory of rectangular line shape factor and the theory presented in ref. [5]. For the idealized configuration of the mixing layer of diffusion chemical lasers, the specific results corresponding to the theories mentioned above are developed in brief. Analysis shows that for the general case in which the transition is simultaneously inhomogeneous broadened and collisionally broadened, particularly for the case in which the inhomogeneous broadening is dominant, the difference among the results of the two theories of line shape factor and the theory of article [5] are quite significant. The results of the theory of rectangular line shape factor are more precise than those of Lorentz-Gauss line shape factor. And the computing-time required by the theory of rectangular line shape factor is less than that of Lorentz-Gauss line shape factor.
IMAGE PROPERTIES OF TAPERED GRADIENT-INDEX FIBER
YIN ZONG-MIN, ZHU SONG-LAI
1981, 30 (12): 1603-1608. doi: 10.7498/aps.30.1603
Abstract +
Starting from the ray path equation, object-image relationships are found and used to determine the equivalent focal length and the principal planes of tapered GRIN fiber. These equation reduce to the known formulas when m = 0 (that is, for a cylindrical GRIN fiber). The aperture of tapered GRIN fiber is discussed in this paper and the photographs of the image are also included.
WHITE-LIGHT IMAGE ADDITION AND SUBTRACTION BY COLORIMETRIC MEASUREMENT
C. K. CHIANG, H. K. LIU, G. G. MU
1981, 30 (12): 1609-1614. doi: 10.7498/aps.30.1609
Abstract +
Theory and experiment of a new white-light image processing technique for black-and-white image addition and "subtraction" by means of Fourier plane spatial color filtering are described. The intensity transmittances of three (or two) processed images can be expressed in a chromaticity coordinate system of primary colors and so are the results of the addition and/or "subtraction" of the two images.
THE STOCHASTIC FORMULATION OF MICROCRACKS EVOLUTION
XING XIU-SAN
1981, 30 (12): 1615-1623. doi: 10.7498/aps.30.1615
Abstract +
The general problem in various fracture processes microcracks or voids evolution has been investigated by employing non-equilibrium statistical concept and method. The kinetic equation of microcrack evolution is derived from multivariated master equation describing the process of microcracks evolution. The way how to connect micro mechanism with macro process is indicated. And the inherent properties of distrubution function of microcracks is discussed.
STATISTICAL THEORY OF I(1) MODEL ANTIFERROMAGNE-TISM ON A FACE CENTERED CUBIC LATTICE WITH NEAREST-NEIGHBOR INTERACTION——A SERIES EXPANSION METHOD
XU WEN-LAN, LI YIN-YUAN
1981, 30 (12): 1624-1636. doi: 10.7498/aps.30.1624
Abstract +
The antiferromagnetism of Ising spin I(1) with the nearest neighbor interaction -J on fcc has been treated by the method of series expansion similar to [1]. The free energy function for the lower temperature ordered state is written in a series of exp(-J/kT) and that for the higher temperature disorder state in a series of J/kT. Using the Padé approximants we have shown clearly that the free energy curves of the two states cross at Tc= 1.33 J/k. The transition is one of the first order, the same conclusion as we obtained for the I(1/2) model, but Tc of I(1) is lower than that of I(1/2). The thermodynamic quantities such as the long-range and short-range order parameter, the internal energy, the entropy, the specific heat as well as the magnetic susceptibility were calculated in variation with temperature. They all change abruptly at Tc.We concluded that (1) on fcc the Ising spin AM-PM transtion being one of the first order should be attributed to the close-packing characteristics of this lattice; and (2) Tc(s) decreases as s increases.
BIFURCATION SOLUTIONS OF BROWN'S EQUATION AND PROBLEM OF FORMATION OF INCIPIENT MAGNETIC DOMAIN
LI BO-ZANG, PU FU-CHO
1981, 30 (12): 1637-1648. doi: 10.7498/aps.30.1637
Abstract +
The problem of formation of incipient magnetic domain in the scheme of Brown's equation is one of the typical problems of bifurcation. A scale transformation is introduced, so that the size of a ferromagnetic body appears explicitly as a parameter in the expressions of free energy and Brown's equation. We generalize the perturbation method in bifurcation theory to study the initial bifurcation of Brown's equation. After an analysis of the stability of single-domain state and bifurcation solutions, we arrived at the conclusion that the critical size of incipient domain formation equals to the smallest positive bifurcation point of size parameter and the process of incipient domain formation takes place either continuously following the bifurcation solutions starting from this bifurcation point or discontinuously with a jump at this point. The criteria for discriminating the continuity and discontinuity of such a transition were given. In addition, we also obtained the lower and upper limits of the precise critical size of single-domain, and also its exact value in particular cases.
NON-LINEAR ELECTRON MAGNETIC-DRIFT WAVES
ZHANG YANG-ZHONG
1981, 30 (12): 1649-1658. doi: 10.7498/aps.30.1649
Abstract +
In this paper, the electron magnetic-drift waves have been treated by the renorma-lization theory in the drift approximation with shear-free magnetic field, and its relations with the anomalous electron transport on Tokamak's analyzed. The resultant diffusion coefficient D⊥~(ωpe(T/eB0Lnk⊥2) roughly agrees with the present Tokamak experiments.
THE TRANSFORMATION PROPERTIES OF CONSTRAINED SYSTEM
LI ZI-PING
1981, 30 (12): 1659-1671. doi: 10.7498/aps.30.1659
Abstract +
The motion of constrained system may be described in terms of non-independent state functions. We considered the change of the action integral and constraint equations under the infinitesimal transformation of the time-space points and state functions of the constrained system, this leads to the general transformation result. We obtained the general equations for the transformation properties of constrained system along the trajectory of motion of that system. From these equations, the condition under which the transformation of constrained system yields conservation law can be worked out. For some specific transformations of the continuous system, we have found the equations of transformation properties. In the special cases, the general equations of transformation properties can be reduced to the results the classical Noether's theorem, The application of general results to classical mechanics is discussed in detail and the Poincare-Cartan invariant is generalized to the constrained system.
BRIEF REPORT
ROTATIONAL STRIATIONS IN CZOCHRALSKI-GROWN LiNbO3 SINGLE CRYSTALS
MING NAI-BEN, HONG JING-FEN, SUN ZHENG-MIN, YANG YONG-SHUN
1981, 30 (12): 1672-1675. doi: 10.7498/aps.30.1672
Abstract +
We intentionally render the rotational axis of growing crystal to deviate from the symmetry axis of the temperature field, the temperature fluctuations with sinusoidal form in meniscus are produced. The one-to-one correspondance between speed of crystal revolution temperature fluctuations, surface growth striations and interior growth striations have been demonstrated.
INVESTIGATION OF CONSTITUTIONAL SUPERCOOLING IN LITHIUM SODIUM STRONTIUM NIOBATE CRYSTALS GROWN BY CZOCHRALSKI METHOD AND IMPROVEMENT OF CRYSTAL QUALITY
XIAO CHAO-MANG, LU KUN-QUAN, ZHU BO-LIAN, WANG CHANG-QING
1981, 30 (12): 1676-1680. doi: 10.7498/aps.30.1676
Abstract +
The constitutional supercooling in single crystal grown by Czoehralski method has been studied by observing grind and polished and etched specimen with microscopy method. Structure transition temperature of the SNLN crystals has been studied under high temperature utilizing polarization lightmicroscope. The constitutional supercooling and internal growth striation in the SNLN crystals have been overcome and the optical homogeneity of the crystals have been improved by employing optimum growth condition and technique.
DETERMINATION OF CRYSTAL STRUCTURE OF BENZOYL PERFLUORO-PROPENYL METHYLENE TRIPHENY-LARSORANCE (YLID-VI)
ZHENG QI-TAI, ZHENG CHAO-DE, SHEN FU-LING, BAI XION-LING, ZHONG FU-MING
1981, 30 (12): 1681-1687. doi: 10.7498/aps.30.1681
Abstract +
Benzoyl Perfluoro-propenyl Methylene Triphenglarsorance (Ylid-VI) crystal is colourless and transparent. The space group is C2H5-P21/a. The crystal belongs to monoclinic system. The parameters of unit cell are a = 10.365 (8)?, b = 29.106 (4)?, c = 8.630 (8)?, β = 107.20 (28)°. There are four molecules in an unit cell (z = 4). The intensity data were collected on PW-1100 four circle diffraetometer, the total number diffraction amounts to 4966. The Ylid-VI crystal structure has been refined by means of block matrix least square method, R = 0.067.The molecular structure of Ylid-VI indicats that there occurs a eletronic transition between the arsenic atom and the carbon atom in the methene.
REMARKS ON QUANTUM BEAT EXPERIMENT OF HIGHLY EXCITED SODIUM ATOMS
ZHU XI-WEN
1981, 30 (12): 1688-1692. doi: 10.7498/aps.30.1688
Abstract +
A few analytical expressions for the observables in a quantum beat experiment is derived, which can be used to describe the experimental results and to obtain the fs splitting in sodium D states. The, change of the n2D states of sodium atoms in a weak electric field is also discussed.
AN ANALYTIC DERIVATION FOR THE MCMILLAN Tc FORMULA (Ⅲ)
WU HANG-SHENG, GU YI-MING
1981, 30 (12): 1693-1698. doi: 10.7498/aps.30.1693
Abstract +
The Tc formula obtained in the previous two papers of this series is generalized to the following form: Tc=αωlog(ωlog/ωc)(μ*/(λ-μ*))exp{-(1+λ)/(λ-μ*)}, and a set of equations to be used to calculate the function a, is derived from the linear Eliashberg equation. a is a function of λ and μ* in general. In the weak coupling limit, we obtain a = 2γ/π from the set of equations mentioned above, where Inγ = C = 0.5772 is the Euler constant. Hence the Tc formula obtained in the two previous papers is correct in the same limit. We further calculate numerically the value of a when λ=0.23, 0.25, 0.38 and 0.48 from the set of equations mentioned above for the case of the Einstein spectrum and μ*= 0. Our results show that at least, in the interval 0.23 ≤λ≤ 0.48, a is vary small and equal to 1/1.30 approximately. With this value of a, the Tc formula obtained by us reduce practically to the empirical McMillan Tc formula in the version proposed by Allen and Dynes.
THE SYMMETRY TRANSFORMATIONS OF THE CONSTRAINED SYSTEM
LI ZI-PING
1981, 30 (12): 1699-1706. doi: 10.7498/aps.30.1699
Abstract +
The motion of constrained system may be described in terms of the non-independent state functions. Suppose the action integral and constraint conditions of this system are invariant under the symmetry transformations of the time-space points and state functions, then we can generalize the Noether's theorem to this constrained system. In general, it does not yield the conservation laws as ordinary Noether's theorem. However, when the system only subjects to finite constraint, the generalized Noether's theorem can reduce to the results as ordinary Noether's theorem.
PROLATE ELLIPSOLIDAL BAG MODEL FOR THE HADRON WITH HEAVY QUARKNIUM
WANG JIA-ZHU, BI PIN-ZHEN, YIN PENG-CHENG
1981, 30 (12): 1707-1712. doi: 10.7498/aps.30.1707
Abstract +
The static prolate ellipsolidal bag model is discussed in this paper, and it is compared with the spherical bag model and the string-like bag model. The relations between the ellipsolid shape and the energy and 2d, the separation between quarks, are obtained. The cases for B=0 and σ=0 are discussed respectively.
REVISION OF KASNER METRIC BY VGM-GRAVITATION THEORY
WANG YONG-JIU, TANG ZHI-MING
1981, 30 (12): 1713-1716. doi: 10.7498/aps.30.1713
Abstract +
In this paper, according to the VGM theory of gravitation, we have found, under certain conditions, the vector graviton field and the metric field of an infinitely long mass line, and compared it with the solution of G.E. field equation (Kasner metric).