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Vol. 33, No. 8 (1984)

1984-04-20
CONTENT
THE REFRACTION OF 4th SOUND BY SUPERLEAK GRAINS IN Hell
WANG BEN-REN, WEI RONG-JUE
1984, 33 (8): 1065-1074. doi: 10.7498/aps.33.1065
Abstract +
From the point of view of the average compressibility and density, and based on the theory of multiple scattering, the effects of superleak grains on the propagation of the 4th sound in liquid helium Ⅱ have been dicussed. The formulas of the index of refraction both (6) and (31) are obtained. The results of numerical calculations show the role of the former is negligible but the variation of 4th sound velocity due to the multiple scattering agrees well the experimental values given in the literature.
THE STEP STRUCTURES EFFECT OF DC JOSEPHSON CURRENT WITHIN ONE FLUX QUANTUM PERIOD φ0(Ⅱ)—— JOSEPHSON JUNCTION WITH LARGER DIMENSIONS
ZHANG YU-HENG, SHEN XIU-LING, WU YAN, ZHENG JIE-FEI, WANG MAO-QUAN
1984, 33 (8): 1075-1083. doi: 10.7498/aps.33.1075
Abstract +
We point out that by placing a large Josephson junction in high Q-value cavity whose rth eigen mode is excited by the Josephson frequency ω0=2cV0/h, the oscillating electromagnetic field will act on the juntion and one must recognize that the space part of the eigen mode of the field are not the same on the junction. We have obained theoretical result which is different from paper [2] and shows how the step structure current vary with the magnetic field. The match condition for eigen mode of the feedback field from the cavity and electromagnetic field radiated by Josephson junction has been worked out. Finally, the physical reason for the absence of step structure with period less than φ0 is given.
MAGNETIC AND ELECTRIC PROPERTIES OF AMORPHOUS (Fe1-xVx)84B16 ALLOYS
ZHANG SHENG-HUA, ZHAN WEN-SHAN, SHEN BAO-GEN, ZHAO JIAN-GAO
1984, 33 (8): 1084-1091. doi: 10.7498/aps.33.1084
Abstract +
Experimental results on some amorphous alloys with composition (Fe1-xVx)84B16 are summarized for x= 0 to 0.1 The temperature dependence of saturated magnetization and high temperature resistivity have been studied. The average moment for one magnetic atom decreases almost linearly with x. The calculated average moment are 2.08μB per Fe atom and -5.08μB per V atom. The Curie temperature Tc decreases from 622 (x = 0) to 478K (x = 0.10). Spin wave stiffness constant D is calculated using the relation σ(T)/σ(0) = 1-BT*
THE INFLUENCE OF OPTICAL ACTIVITY ON RAMAN SCATTERING IN α-QUARTZ
PEI LI-WEI, JIA WEI-YI
1984, 33 (8): 1092-1099. doi: 10.7498/aps.33.1092
Abstract +
The influence of optical activity on Raman scattering is discussed. Some pure Raman spectra of α-quartz with this effect eliminated have been obtained. Based on these results the nonequivalence between x and y axes in Raman spectra of the unia-xial α-quartz under some scattering geometries has been analyzed.
APPROXIMATE CALCULATION OF THE TILTING MODE INSTABILITY IN AN ELLIPTICAL SPHEROMAK BY VARIATIONAL METHOD
WU HAN-MING, PAN LIANG-RU
1984, 33 (8): 1100-1111. doi: 10.7498/aps.33.1100
Abstract +
Based on the variational principle, a new method for appoximately solving partial differential equation with an arbitrary boundary shape is proposed. Accordingly, the problem of solving a partial differential equation is reduced to one of solving a series of ordinary differential equations. This method proves to be more powerful when the boundary shape gets complicated. An application is made to the problem of the tilting mode instability for spheromak without restriction in ellipticity. The following physical conclusion is arrived at, namely, the oblate spheromak is better than elongated one as far as suppressing the tilting mode instability is concerned.
RESISTIVE FLUID INSTABILITY AT THE NONMONOTONOUS CURRENT PROFILE
MA TENG-CAI, GONG YE
1984, 33 (8): 1112-1119. doi: 10.7498/aps.33.1112
Abstract +
It can be shown that the dynamics of magnetic perturbation at the nonmonoto-nous profile of a current in tokamak is qualitatively different from that of normal profiles. Behaviour of the perturbation depends on the helical magnetic currents localized mainly between the two singular surfaces. In this paper the numerical method developed to study the non-linear evolution of tearing modes is described in detail.
GENERAL EXPRESSIONS OF THE CHARACTERISTIC FREQUENCY AND GRüNEISEN COEFFCIENT FOR SOLIDS
ZHANG WAN-XIANG
1984, 33 (8): 1120-1128. doi: 10.7498/aps.33.1120
Abstract +
Starting from the general expresson of frequency given by the dynamical theory of crystal lattices, we have derived three different expressions of the characteristic frequency for three kinds of solids, and re-obtained rS,rD-M and rf. We pointed out that rS,rD-M and rf. belong to three different models of solids. Finally, the general expressions of the characteristic frequency ω and Grüneisen coefficient γ for solids were found.
A DIRECT DERIVATION OF THE KERR-NEWMAN METRIC
GUI YUAN-XING, CHEN FANG-PEI, ZHANG JI-GUANG, ZHANG YANG
1984, 33 (8): 1129-1136. doi: 10.7498/aps.33.1129
Abstract +
A direct derivation of the Kerr-Newman metric and corresponding electromagnetic field from Einstein-Maxwell equation by elementary methods is given in this paper.
CALCULATION OF PROJECTED ION-RANGE DISTRIBUTION MOMENTS IN COMPOUNDS AND ALLOYS (Ⅱ)——RANGE DISTRIBUTION MOMENTS FOR LIGHT IONS (Z1≤10)
XIA YUE-YUAN, YANG HONG, TAN CHUN-YU, SUN XIU-FANG, GAO SHOU-WEN
1984, 33 (8): 1137-1148. doi: 10.7498/aps.33.1137
Abstract +
An empirical formula of electronic Stopping Cross Section, Se, for low energy ions, such as Li+,Be+,B+,C+,N+,O+,F+ and Ne+, in solid materials is established according to the experimental electronic stopping power data in solid media. The formula can be used not only to describe the experimental Z1 and Z2-oscillation of electronic stopping power, but also to describe very satifactorily the Se varying with ion energy, E. The projected rang distribution moments up to third order for ten light ion species from H+ to Ne+ in different substrates, such as amorphous Al2O3,SiO2, 20/25/Nb stainless steel, LiNbO3 and UO2, are calculated by use of the electronic stopping cross section formula proposed by the present authors and the nuclear scattering function which agrees with the WHB atomic interaction potential. Our theoretical results are compared with the experimental results published recently, and our projected ranges, Rp agree with the experimental measurements more closely in the low energy end of the energy regime which we deal with in the present work.
A STUDY ON MIGRATION OF Li IONS IN α-LiIO3 SINGLE CRYSTAL UNDER AN ELECTROSTATIC FIELD APPLIED ALONG THE c-AXIS BY 6Li (n, α)t NUCLEAR REACTION
YANG TONG-HUA, BAO ZONG-YU
1984, 33 (8): 1149-1154. doi: 10.7498/aps.33.1149
Abstract +
The detailed information about the migration of Li ions under an DC electric field applied along the c-axis of an α-LiI03 single crystal has been obtained by analysing the spectrum of the nuclear reaction 6Li (n, α)t in the single crystal bombarded by thermal neutrons. The migration of Li ions in the crystal can be continuously studied non-destructively by this method. The results show that the Li ions have migrated into Al-electrode when 0.1 Columb of charge is accumulated and have penetrated the Al-electrode at 0.3 Columb. The relutive density of the Li ions at various depth in the single crystal have also been measured versus different amount of accumulated charge.
BRIEF REPORT
PHASE DIAGRAM OF THE ALLOYS IN Gd-Sn BINARY SYSTEM
LIU JING-QI, ZHENG JIAN-XUAN
1984, 33 (8): 1155-1159. doi: 10.7498/aps.33.1155
Abstract +
The phase diagram of gadolinium-tin system has been completed by X-ray method in conjunction with differential thermal analysis. Three new intermetallic compounds: Gd3Sn,Gd8Sn7 and Gd3Sn4, were observed.In this system, there exist eight intermetallic compounds:Gd3Sn,Gd5Sn3,Gd5Sn4,Gd8Sn7,Gd11Sn10,Gd3Sn4,GdSn2 and GdSn3. The intermetallic compounds Gd3Sn and Gd5Sn3 melt congruently at 1173℃ and 1243℃, and the intermetallic compounds Gd5Sn4, Gd8Sn7, Gd11Sn10, Gd3Sn4, GdSn2 and GdSn3 are foymed by Six peritectic reactions at 1179℃,, 1114℃, 1095℃, 995℃,941℃, and 905℃, respectively. Three eutectic reactions occur at 15at% Sn and 1103℃, 32at% Sn and 1141℃, l00at% Sn and 232℃ Neither Gd in Sn nor Sn in Gd Shows any detectable solid solubility.
CALCULATION FOR THE SPLITTING CHAIN OF CRYSTAL-FIELD ENERGY LEVELS OF Pr3+-DOPED LiYF4 CRYSTAL
XIU SHANG-DA, HUANG FU-HUA, XU PENG-SHOU
1984, 33 (8): 1160-1166. doi: 10.7498/aps.33.1160
Abstract +
In this paper. Tang's tensor operator method is applied to a fitting calculation of crystal-field energy levels of the rare earth ions. The splitting chain of energy levels of LiYF4: Pr3+,crystal-field parameters and approximate wave functions cor-reoponding to the crystal-field group chain R3?Td?D2d?S4 are ohtoined. These results can he used to analyse various prohlems, such as space charge distribution, spectral line intensity and other optical, magnetic and thermodynamic properties in cases with different approximate symmetry.
GROWTH AND OPTICAL PROPERTIES OF K5Bi0.9Er0.1(MoO4)4 SINGLE CRYSTALS
LIU JIAN-CHENG, TANG LIAN-AN, CHEN JIA-PING
1984, 33 (8): 1167-1171. doi: 10.7498/aps.33.1167
Abstract +
Single crystals of 5Bi0.9Er0.1(MoO4)4 were grown from stoichiometric melts by the usual Czochralski technique. The crystal belongs to trigonal system, with space group R3m , z=1.5, and cell parameters a=6.029?, c=20.823? (hexagonal setting). Due to the layered structure, the crystals exhibit easy cleavage along (0001) face. The room temperature absorption spectrum of 5Bi0.9Er0.1(MoO4)4 consists of severalbands characteristic for the rare earth ions in crystals. The spectrum is dominated by three absorption bands associated with transition from the ground 4I15/2 level of Er3+ to the 4G11/2, 2H11/2 and 4I13/2 levels, Details of room temperature emission Spectra Corresponding to the 4I13/2→4I15/2 transition are also given.
WHITE LIGHT DYE LASER
ZHANG FU-GEN, YU CHUN-LIAN, MIAO HAI-PING, YANG CHEN-GUANG
1984, 33 (8): 1172-1176. doi: 10.7498/aps.33.1172
Abstract +
In this paper, we report the experimental results of obtaining white light dye laser using the mixed system of two laser dyes. This white light laser has the turnable characteristic of the output wavelength and intensity of its three basic colours respectively. We have also analysed the conditions which shoud be satisfied by the mixed system of two laser dyes in multi-colour operation.
ELECTRON SPIN RANDOMIZATION OF OPTICALLY PUMPED ALKALI-ATOMS IN THE SPIN TEMPERATURE LIMIT
PAN SHAO-HUA, HOU MEI-YIN
1984, 33 (8): 1177-1181. doi: 10.7498/aps.33.1177
Abstract +
The behavior of electron spin randomization of optically pumped alkali-atoms in the spin temperature limit is treated theoretically in this article. Numerical solutions of the relaxation equation of motion are presented. And a generalized slowing down factor as a funtion of the polarization and nuclear spin is analysed in detail.
CRYSTALLIZATION PHASES IN AMORPHOUS Ni-P ALLOY
LAI ZONG-HE, WU YU-KUN, GUO KE-XIN
1984, 33 (8): 1182-1186. doi: 10.7498/aps.33.1182
Abstract +
Vafaei-Makhsoos claimed to have discovered three new Ni3P phases in crystallized Ni-P amorphous alloy. By analysis of his experimental data as well as our own electron diffraction experiments, it is shown that the various electron diffraction patterns of the so-called new Ni3P phases are in fact all belonging to Ni12P5. Thus it is clear that there are seven crystallization phases in annealed amorphous Ni-P alloys: metastable fcc phase α (α=5.48?), metastable hexagonal polytypes α1,α2,α3 transformed from α, bct Ni12P5, bct Ni3P and Ni solid solution.
αs(Q2) AND INTERACTION POTENTIAL BETWEEN THE HEAVIER STRATONS
GOU LIANG, HUANG TAO
1984, 33 (8): 1187-1191. doi: 10.7498/aps.33.1187
Abstract +
In this letter, we suggest a possible interaction potential between the heavier stra-tons by considering the asymptotic freedom at the lorge Q2 and the multi-gluons effect at the lower Q2 in the QCD, and calculate the spectrum of the J/ψ and the γ families. The result is in agreement with experiments. In addition, we discuss a possible mass spectrum of T(tt) family.
LETTERS
ANOMALIES OF LiNbO3 CRYSTAL IN CONOSCOPIC INTERF-ERENCE PATTERN AND REFRACTIVE INDEX BETWEEN ROOM TEMPERATURE AND 130℃
XU ZI-RAN, SHEN HUI-MIN, WANG XIAN, WANG YE-NING
1984, 33 (8): 1192-1195. doi: 10.7498/aps.33.1192
Abstract +
Conoscopic interference pattern in pure and doped LiNbO3 (LN) has been investigated with the light propagated along z direction. Anomalous change of birefrigence is observed at about 45 ℃ as well as 75 ℃ in pure LN. The crystal changes from uniaxial crystal to biaxial crystal near these two temperatures. Similar phenomena also occur in doped LN, but the temperature ranges of the anomalies are widened. The index of refraction n0 and ne were both measured. Abrupt changes are also discovered at about 45℃ and 75℃ . The behavior of conoscopic interference at 75℃ is very similar to that of the electrooptic effect with the electric field being applied along x direction of LN at room temperature. This suggests that the anomalous change at 75℃ in LN is caused by internal electric field of about 105V/m resulting from the displacement of ions along x direction in LN.
PSEUDO WEAK PHASE OBJECT APPROXIMATION IN HIGH RESOLUTION ELECTRON MICROSCOPY
LI FANG-HUA, TANG DONG
1984, 33 (8): 1196-1197. doi: 10.7498/aps.33.1196
Abstract +
A pseudo weak phase object approximation to the principle of image formation in high resolution electron microscopy is presented. It is pointed out that there is the possibility of preferential revealing lighter or heavier atoms in the crystal structure in high resolution electron micrographs by choicing different crystal thickness.
POLARONS IN A 1:3 PEIERLS SYSTEM
XING DING-YU, GONG CHANG-DE
1984, 33 (8): 1198-1201. doi: 10.7498/aps.33.1198
Abstract +
Using the continuum limit of SSH model, we find explicitly the "polaron" soliton in one-dimensional Peierls system with commensurability-3. It is shown within the weak-coupling limit that the polaron solution satisfies exactly the self-consistent condition for the order parameter of the ionic displacements. The creation energy and characteristic width of the polaron are given. Furthermore, the possible soliton excitations in the general commensurability-M case are discussed.
SUPERCONDUCTING PROPERTIES OF GETTER SPUTTERED Mo1-xSix FILMS
ZHAO ZHONG-XIAN, MENG RU-LING, ZHOU PING, LI LIN
1984, 33 (8): 1202-1204. doi: 10.7498/aps.33.1202
Abstract +
The superconductivity properties of four Mo1-xSix thin films were measured. The results of superconducting transition temperatures, the critical magnetic fields near Tc, the critical current densities at 4.2 K and room temperature (300K) and low temperature (8 K) resistivity measurements indicated that the four samples showed characteristic features of amorphous films, the Mo78Si22 film showed better ‘ amorphousness' among them.