Vol. 33, No. 8 (1984)
1984, 33 (8): 1065-1074. doi: 10.7498/aps.33.1065
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
1984, 33 (8): 1075-1083. doi: 10.7498/aps.33.1075
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  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.
1984, 33 (8): 1084-1091. doi: 10.7498/aps.33.1084
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*
1984, 33 (8): 1092-1099. doi: 10.7498/aps.33.1092
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
1984, 33 (8): 1100-1111. doi: 10.7498/aps.33.1100
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.
1984, 33 (8): 1112-1119. doi: 10.7498/aps.33.1112
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.
1984, 33 (8): 1120-1128. doi: 10.7498/aps.33.1120
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.
CALCULATION OF PROJECTED ION-RANGE DISTRIBUTION MOMENTS IN COMPOUNDS AND ALLOYS (Ⅱ)——RANGE DISTRIBUTION MOMENTS FOR LIGHT IONS (Z1≤10)
1984, 33 (8): 1137-1148. doi: 10.7498/aps.33.1137
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
1984, 33 (8): 1149-1154. doi: 10.7498/aps.33.1149
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.
1984, 33 (8): 1155-1159. doi: 10.7498/aps.33.1155
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.
1984, 33 (8): 1160-1166. doi: 10.7498/aps.33.1160
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.
1984, 33 (8): 1167-1171. doi: 10.7498/aps.33.1167
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.
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.
1984, 33 (8): 1177-1181. doi: 10.7498/aps.33.1177
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.
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.
1984, 33 (8): 1187-1191. doi: 10.7498/aps.33.1187
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.
ANOMALIES OF LiNbO3 CRYSTAL IN CONOSCOPIC INTERF-ERENCE PATTERN AND REFRACTIVE INDEX BETWEEN ROOM TEMPERATURE AND 130℃
1984, 33 (8): 1192-1195. doi: 10.7498/aps.33.1192
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.
1984, 33 (8): 1196-1197. doi: 10.7498/aps.33.1196
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.
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.
1984, 33 (8): 1202-1204. doi: 10.7498/aps.33.1202
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.