Vol. 35, No. 11 (1986)
1986-06-05
CONTENT
1986, 35 (11): 1403-1410.
doi: 10.7498/aps.35.1403
Abstract +
In the shemes of Migdal and Migdal-Kadanoff renormalization group transformation, the strong coupling (high temperature) approximation and weak coupling (low temperature) approximation for U(l) lattice gauge theory are introduced, and the numerical results, including those for the intermediat coupling region, are given. We compare the results obtained by means of these transfomations with the exact results of strong coupling and weak coupling expansions and the recent Monte-Carlo calculation.
1986, 35 (11): 1411-1425.
doi: 10.7498/aps.35.1411
Abstract +
We have studied the kinetic effects on ballooning-mode more completely from the gyro-kinetic theory. Here we have consideres the effects of the following factors, i. e., collision, hot-ion components such as neutral beam injection or fusion α-particles, particle diamagnetitc drift, ion gyro-radius ,as well as trapped particles. It has been shown numerically that both gyro-radius of ion and trapped particles have stabilizing effects on ballooning-mode, whereas the collision term has the destabilizing effect besides, the kinetic theory reproduces the results given in Ideal MHD theory, i.e. the shear can improve the stability of ballooning-mode.
1986, 35 (11): 1426-1435.
doi: 10.7498/aps.35.1426
Abstract +
In this paper, the expression for the double probe V-l characteristics and a formula to determine the electron temperature are derived. They are applicable whether the R. F. disturbance voltage drop across the probe sheath exists or not. The influence of this R. F. disturbance voltage on the double probe diagnostics for a low pressure plasma is investigated. Furthermore, the electron temperatures of the R. F. plasma under the pressure of 10-2—10-3 Torr are obtained experimentally. Experimental results agree with the theoretical analysis very well, k is also demonstrated that, if the electron energy distribution is Maxwillian, the R. F. disturbance has no substantial effect on the determination of electron temperatures of the plasma.
1986, 35 (11): 1436-1446.
doi: 10.7498/aps.35.1436
Abstract +
In this paper, a new waiting time distribution function (WTDF), ψ(t), is adopted to discuss asymptotic solutions of the continuous-time random walk (CTRW) problems. This WTDF is not purely exponential and is universally valid for explaining the low-frequency (say, ω<10GHz) fluctuation, dissipation and relaxation properties of condensed matter. Many theoretically meaningful results are obtained, and they are in agreement with experiments, These results include the mean displacement, the dispersive mobility, the meansquared displacement, the dispersive diffusion coefficient, Nernst-Einstein relation, the variance and the standard variance, the lattice statistics, the initial site occupation probability, the dispersive conductivity, the dispersive electrical transport and the memory function. All results show that the CTRW process described by the WTDF ψ(t) behaves as non-Markovian over the very broad time domain and as Markovian only in long time limit, this is to say all results contain a single parameter, n, the infrared divergence exponent, which depends on the microscopic structure of condensed matter and determines the degree of dispersion. The larger the value of n is, the stronger the dispersion becomes. When n= 0, the dispersion disappears and all results reduce immediately to the classical Markovian forms.This is in agreement with receat experimental facts.
1986, 35 (11): 1447-1456.
doi: 10.7498/aps.35.1447
Abstract +
To elucidate the promotion action of cobalt on Mo sulfide catalysts, UPS, XPS and LEED have been applied to study the submonolayer deposite process of promotor metal Co on the active catalytic phase for Co-Mo catalyst-the highly edged surfaces and ion sputtered basal plane of MoS2 crystal. At a certain submonolayer coverage of deposited Co, the new Co-correlated interface states could raise surface EF to a new higher pinning position by about 0.30-0.35eV. So the surface barrier and work function for these catalytic active phases are decreased. The remarkable changes for electronic structure near EF and the studies of LEED patterns reveal that the active phase Co-Mo-S, in which the Co-Mo bond appears to behave in much the same way as in the intermetallic bond, could be formed by locating the promotor Co at the surface disorder defects in edge sites.
1986, 35 (11): 1457-1464.
doi: 10.7498/aps.35.1457
Abstract +
The wavefunctions of the Eu, state and the Eg state are evaluated for the ideal divacancy in Si, using the basic equations given in [1] and the tight binding Hamiltonian given by P. Vogl et al. Comparison between the culculated results and the ESR and ENDOR spectra of V2+ and V2- in Si is discussed.
1986, 35 (11): 1465-1472.
doi: 10.7498/aps.35.1465
Abstract +
This is the first theoretical calculation covering the whole energy range in LaFa3Nd3+ by using a crystalfield Hamiltonian of C2 point symmetry. The rms deviation is about 20.2 cm-2. Thus far, this calculation is the most accurate one. We also correct the previous assign ments of some sub-levels.
1986, 35 (11): 1473-1479.
doi: 10.7498/aps.35.1473
Abstract +
The approach of measuring all the electro-elastic constants for the crystals of D3(32) class has been developed by means of the vibrational theory for piezoelectric plates. As an example, all the electro-elastic constants of α-Quartz have been obtained using the approach.
1986, 35 (11): 1480-1487.
doi: 10.7498/aps.35.1480
Abstract +
This paper reports a study of the quasi real space (QRS) method. It is an intermediate procedure between the real space (RS) and multislice (MS) methods. With this technique, most of the numerical calculations are done in real space except that the rormalization is imposed beyond some threshold value, for example ∑|Φ|2>1.01 where Φ is the wave function of the electron. It is also shown why truncation of the propagation operator eλε△ to second order in the RS method can lead to computational divergencies and how they can be avoided by using the QRS method. Finally, results calculated by the QRS method are compared with other existing slice methods. The QRS method gives results similar to the conventional MS calculation with competitive computational speed.
1986, 35 (11): 1488-1495.
doi: 10.7498/aps.35.1488
Abstract +
In this paper, the relativistic fifth order geometrical aberration equation of a combined electric-magnetic focusing-deflection system with superimposed fields is derived by using varia-tional principle and taking symbolic derivative and inner product of complex numbers as mathematical tools.
1986, 35 (11): 1496-1501.
doi: 10.7498/aps.35.1496
Abstract +
The amorphous Y5Ni95 alloy films were hydrogenated bv electrolysis. The dependences of magnetization, resistivity and Hall resistivity on H content were measured respectively for a-Y5Ni95Hx in the temperature range from 1.5K to 400 K. Results show that the average moment at 0 K, the Curie temperature and the temperature coefficient of resistivity decrease with increasing H content. While the high field susceptibility, resistivity and extraordinary Hall coefficient increase quickly. These effects of hydrogen are discussed in terms of the current theories.
1986, 35 (11): 1502-1510.
doi: 10.7498/aps.35.1502
Abstract +
The low temperature magnetic properties of the amorphous Sm-Fe and Sm-Co thin films are investigated. It is found that there exists a distribution of the orientation of the Fe atomic moment in the Sm-Fe films, and the compositional dependence of the effective magnetic moments of the Co atoms in the Sm-Co films is very similar to that of the amorphous Nd-Co films. The magnetic structures of these two alloy systems are determined: there are asperomagnetic structure for the Sm-Fe thin films and the collinear ferromagnetic structure for the Sm-Co thin films. The magnetic moment of Sm atoms is very close to zero. The strength, temperature and compositional dependences of coercivity for these two amorphous alloy systems are measured. The Hc of Sm-Fe films is much larger than that of Sm-Co films, For the Sm-Fe amorphous films, Hc increases very quickly with increasing of the contants of samarium, and severely drops with increasing of temperature in the very low temperature region. But for the Sm-Co amorphous films, Hc reaches a maximum at about 43 at% Sm, and decreases with increasing of temperature in the exponental form. It is also found that the temperature dependence of magnetization in the low temperature region may be caused by the Bloch spin-wave excitation and Stoner electric excitation simultaneously.
1986, 35 (11): 1511-1520.
doi: 10.7498/aps.35.1511
Abstract +
A model is proposed to describe the diffusion and release behaviour of inect gases implanted into various solids. According to this model, in which the interactions between different defects or radiation damage and the inert gas atoms are taken into account, a set of diffusion equations is derived and the analytical solutions of these equations are obtained.The comparison between the theoretical results and the experimental results shows that this model can be used to describe the release of inert gases from the surfaces of solids very well. By least-squares fitting the theoretical release curve to that of the experiment, a method to determine the activation energies of different trapping centres and the trapped concentration is provided.
BRIEF REPORT
1986, 35 (11): 1521-1527.
doi: 10.7498/aps.35.1521
Abstract +
The soft optic mode spectra of monoclinic I lanthanum pentaphosphates LnP5O14(Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) are measured in the range of 20-300℃. The Ag-B2g and Ag-Ag soft modes in different LnP5O14 all soften to 20 cm-1 at ferroelastic transition temperature Tc. Another Bg-B3g soft mode softens to 38cm-1 at Tc. The coupling of Ag-B2gsoft mode with e5, plays an essential role in the phase trasition and the temperature dependence of soft-mode intensity can be described by means of the bilinear mode-coupling model. The increment of Tc from La to Tb in this system is owing to the lanthanum contraction.
1986, 35 (11): 1528-1531.
doi: 10.7498/aps.35.1528
Abstract +
The martensitic transformation in thirteen Fe-Ni alloys has been studied by positron annihilation technique. The experimental results show that the values of the average lifetime f and the lineshape parameter S increase by about 30% and 20% respectively in six annealed and liquid nitrogen quenched alloys (28.22-31.30 wt% Ni). This confirms that the direct transformation produces a great number of defects in these alloys. The changes of the positron parameters with treating temperature have been determined in two different martensitic substructure alloys. It has been detected that the defects are chiefly produced in the stage of the burst martensitic transformation. Two distinct stages in the isochronal annealing curve confirm that the defects formed in the direct transformation mainly consist of vacancies and dislocations.
1986, 35 (11): 1532-1536.
doi: 10.7498/aps.35.1532
Abstract +
In the present paper, we report the theoretical investigation results of DyP5O14 single crystals derived from absorption spectra according to the Judd-Ofelt theory. The experimental and theoretical oscillator strengths and three phenomenological intersity parameters are calculated. After evaluation the reducible matrix elements, the fluorescent radiative transition probabilities are obtained.
1986, 35 (11): 1537-1541.
doi: 10.7498/aps.35.1537
Abstract +
Clusters, which do must not have the same periodic structure as the corresponding large crystal, can also show an optical absorption similar to the crystal. In the present article, we report the results about the preparation and optical absorption properties of glasses containing CuClxBr1-x(x=0—1) colloids. Experimental results indicate that colloidal CuCl, CuClxBr1-x and CuBr in glasses with definite size can also show exciton absorption peaks similar to the corresponding large crystals, and that glasses have the same violet absorption edges as the crystals.
1986, 35 (11): 1542-1546.
doi: 10.7498/aps.35.1542
Abstract +
Using Green's function technique, we have discussed magnetization of surface and interface changes with temperature from T=0 to T=Tc. For the surface, result is in agreement with other authors. For interface, we not only fird that critical temperature is differente between interface and bulk, but also fird a relation: Tc1 cA,TcB).
