Vol. 35, No. 3 (1986)
THE RENORMALIZED STRONG TURBULENCE THEORY FOR THE LOW-FREQUENCY MAGNETIC FIELD AND THE ION ACOUSTIC WAVE EXCITED BY HIGH-FREQUENCY WAVE
1986, 35 (3): 283-299. doi: 10.7498/aps.35.283
In this paper, the renormalized turbulence theory for the lowfrequency magnetic field and the ion acoustic wave in the high temperature plasma is developed in order to improve the usual weak nonlinear-approach. From Vlasov-Maxwell equations, the coupled renormalized equations of the high and low frequency propagator, with the "most divergence" and "secondary divergence" effects included, are derived in the Fourier representation. Thus, we obtain the coupled relation of the renormalized par-tical distribution function and field for high and low-frequency oscillation.Under "most divergence" renormalization approximation, the propagator equations for high and low-frequency are solved. Expanding to the order of v4—the ratio of the energy density of the high-frequency turbulence field to the thermal energy density of the plasma particle, the approximate solutions for the propagator and the expressions for the renormalized dielectric function are obtained. Then, by performing Fourier inverse transformation, the renormalized strong turbulence equations are derived in the spacetime representation.Finally, as an example which shows the renormalized effects, under onedimensional and stationary approximation, the analytical form for the soliton is solved.
1986, 35 (3): 300-310. doi: 10.7498/aps.35.300
Starting from the kinetic equation in the K space, which is the Fourier space of velocity V and using the technique of operator calculation and transformation, the re-normalized dispersion equation of turbulent plasma has been deriv ed rather simply. The effect of finite correlation time of the turbulence has been calculated under the approximation of assuming a turbulence with effective correlation time τeff instead of the one with time and space correlation. It shows that the effect of finite τeff will reduce the effect of turbulence. Therefore, the expression obtained in the limiting case of short eorrelation time is the upper bound of the turbulence effect. The effects of turbulence on the ion sounds, electron langmuir waves and drift waves have also been discussed.
1986, 35 (3): 311-318. doi: 10.7498/aps.35.311
The effects of self-generated magnetic field on the density profile modification in laserplasma interactions are studied by calculating the field structure, assuming that plane electromagnetic waves propagate into an one-dimensional inhomogeneous magnetized plasma. The results obtained by computation are in agreement not only with the laser-target experiments using Nd-glass laser, but also with that using CO2 laser. In addition, calculations show naturally the density dip which has been observed in experiments.
A STUDY ON THIN FILM WITH COMPLEX REFRACTION INDEX BY SPECTROSCOPIC ELLIPSOMETRY——OPTICAL CONSTANT DISPERION AND GROWTH RATE OF ITO
1986, 35 (3): 319-328. doi: 10.7498/aps.35.319
In this paper, we propose a method which make it possible to investigate the films with complex refraction index using spectroscopic ellipsometry. By introducing a new aiming function, the search parameters space can be reduced to 4-dimension, so we not only can calculate the optical constant and the thickness of the films, but also the optical constant of the substrate simultaneously. Using this method, we studied the optieal constant dispersion and the growth rate of ITO films which is deposited on Si substrate by sputtering. At the same time, we observed that the apparent optical constants of the Si substrate were changed.
The inhomogeneous anisotropic interactions of solids under MAS of slow rotation break up the NMR spectra into a series of spinning sidebands which contain all the information about the interaction tensors. This structural useful information can be extracted by computing and analysing only a few of ths sidebands. This method ,which is applicable for various inhomogeneous interactions and is based on an expansion of the Bessel functions using the irreducible spherical tensor and operator representation of the spin interactions, is reported in the paper. The experimental spectra of typical samples dominated respectively by chemical and quadrupolar interaction agree well with the theoretical ones.
1986, 35 (3): 338-345. doi: 10.7498/aps.35.338
The formation of hard bubbles (including dumbbell domains) in epitaxial garnet films by using a series of pulse bias fields was investigated in some detail. It was found that the effect of a series of pulses is not simply the adding up of that of a single pulse (the physical process of hardening of soft domain segments), but has its own regularity, there exist two other physical processes, i.e. further hardening and softening of hard domain segments. The experimental results can be reasonably interpreted in terms of the above-mentioned three processes.
1986, 35 (3): 346-351. doi: 10.7498/aps.35.346
The 119Sn M?ssbauer spectra of SmCo3.66Fe0.13Sn0.06 PM sintering slices have been studied by M?ssbauer spectoscopy. At tin nuclei, near zero magnetic splitting was observed. It was concluded that the majority of additive tin and iron whose atomic ratio is not less than 2:1 entered into the lattice of SmCo5 homogeneously and the iron-tin neighbour developed an ordered structure. The principal characteristic constituents is similar to FeSn2. The effect of coercive force of these atomic configuration and possibly emerging spin configuration is discussed.
1986, 35 (3): 352-358. doi: 10.7498/aps.35.352
In this paper, structural and magnetic studies are carried out on the alloys of the iron-rich Nd-Fe-B ternary system. The results show that for the iron-rich (Fe>40 at%) alloys ternary compound Nd2Fe2Si2 is formed (Si>20%) as well as pseudobinary compound Nd2(Fe, Si)17, in which Si atoms are substituted for the iron atoms on 9d-sites instead of forming new ternary compound as that of Nd2Fe14B. Upon substitution of Si for Fe, both cell volume and magnetization of the Nd2(Fe,Si)17 alloys decrease, but Curie temperature Tc increases due to an enhancement of the ferromagnetic interaction in the Fe sublattice. The room temperature anisotropy fields decrease with increasing Si eon-tent as a result of reduction of the plane anisotropy in the Fe sublattice.
A TEM STUDY OF THE CRYSTALLIZATION OF AMORPHOUS Ni-Zr ALLOY(I)——METASTABLE PHASES FORMED DURING CRYSTALLIZATION OF Ni67Zr33
1986, 35 (3): 359-364. doi: 10.7498/aps.35.359
The crystallization behaviour of Ni67Zr33 amorphous alloy has been studied by using transmission electron microscopy. Two metastable phases, T0 and T1, have been found at 500℃. The T1 phase has a body centred orthorhombic er pseudo-tetragonal lattice (α≌b=0.89 nm, c=3.14nm) and the Ibα2 or Ibαm space group. As the temperature increases, the metastable phases gradually change into the stable phase T2(Ni10Zr7) containing a lot of faults. The diffraction streaks parallel to c* with h+k ≠ 2n can be explained satisfactorily by the 1/2(α+ b) displac ement of (001) plane in T2. The final stable phases are Ni10Zr7 and Ni21Zr8.
1986, 35 (3): 365-374. doi: 10.7498/aps.35.365
In this article, as-evaporated and annealed samples of Ge/Au, Ge/Ag bilayer films and Ge-Au, Ge-Ag alloy films were investigated by TEM. In situ observations of Ge/ polyerystalline Au (p-Au) and Ge/p-Ag films during heating were also made by TEM. It is found that crystallization temperature Tc of amorphous Ge (a-Ge) in a-Ge/p-Au is much lower than Tc of a-Ge/monocrystalline Au (m-Au). It is shown that the boundary triple points and other interface defects of p-Au films are the favourable nucleating positions for a-Ge crystallization in bilayer films. Tc of a-Ge in the condensation regions of Ge/p-Au films (≈100℃) is lower than Tc (≈150℃) in the noncondensa-tion regions. There are some large Ge grains in the condensation regions because of the effect of favourable crystallization in local regions. Tc of a-Ge in a-Ge/p-Ag and a-Ge/ m-Ag films is about 280℃. Tc of alloy films is higher than that of correlative bilayer films when metallic content in alloy film is low (CAu Agc of alloy films is lower than that of bilayer films when metallic content is relatively high. It is because of smpersaturation metallic atoms which reduce the crystallization potential barrier of a-Ge significantly.
1986, 35 (3): 375-378. doi: 10.7498/aps.35.375
In the inflationary phase of our universe, the true vacuum bubbles, appearing during the non-homogeneous phase transition, may collapse into primordial black holes. The lowest mass limit of them is 104g, and they may accompanied by t'Hooft-polyakov rno-nopoles. This result may have certain observational significance as compared with that of Carr, Hwaking and Wu.
1986, 35 (3): 379-383. doi: 10.7498/aps.35.379
The isothermal internal friction of a Ag-42.3% Cd alloy has been measured by means of a low frequency inverted torsion pendulum apparatus between room temperature and 250℃. The relation between Q-1 and temperature with various heating and cooling rate were determined. Experimental results show that as the bainitic transformation occurs, the Q-1 of Ag-Cd alloy increases rapidly. It may be postulated that there are regions of instability of the parent lattice in the course of nucleation process for the bainitic transformation. The increment of Q-1s is a function of the product of internal friction of the fraction of the lattice localized soft region per volume and the nuclea-tion rate J* of the bainite.
1986, 35 (3): 384-388. doi: 10.7498/aps.35.384
The carbon and oxygen on the Mo (110) surface has been investigated by means of LEED and AES. We found that, after argonion bombardment of Mo (110) surface containing carbon and oxygen with the beam energy 1 keV and beam current 6μA, the Auger, peak shapes and carbon intensities changed. Depth-profile technique showed that carbon was diffused from the bulk. Heating sample to temperature above 700 ℃ or 750℃, two types of LEED patterns of Mo(110) c(4×4)-C, (-4 2 2 2) -C were observed respectively.
1986, 35 (3): 389-392. doi: 10.7498/aps.35.389
The optical phonon spectra for ZrH1.7 (containing 0.2% C) and PdH0.7 are measured at room temperature and low temperature (97 K) -with beryllium filter detector spectrometer adjacent to the heavy water pile in the Institute off Atomic Energy. The results show that: (1) Optical phonon Energy Level for ZrH1.7 is equal essentially spacing, the width of energy level essentially does not change with T i.e. the anharmonicity of optical phonon. is weak and it obeys Einstein harmonic model. (2) The second optical phonon energy level spacing for PdH0.7 is about 8 meV larger than that of the first level spacing, and the width of its optical phonon energy level changes from 38 meV at room temperature to 20 meV at 97 K. This means that the optical phonons which ply important role in supercondectivity of PdHx exhibit significant anharmonicity.
1986, 35 (3): 393-396. doi: 10.7498/aps.35.393
When the effective phonom spectrum is calculated from the electron tunneling spe-ctrum by invertion of strongly coupled superconducting energy gap equation, the electron density of states must be measured under the condition T→OK. Otherwise the error of the electron density of states and the deviation of effective phonon spectrum from the real one will be very large. In this paper a method is given for correcting this temperature effect, and the above-mentioned difficulty can be overcome. The correct effective phonon spectrum, andλand μ* values can be obtained by this method using electron tunneling spectrum data measured even at T/Tc=0.22.
1986, 35 (3): 397-402. doi: 10.7498/aps.35.397
In this paper, we propose a formula (2△0)/(kBTc)=4.95[1-T01/2/A(1/(λω0)+1/(20λ)+1/(20))], it can describe well the relations between 2△0/(kBTc) and the parameters of the phonon spectrum of disordered and amorphous superconductors for the non-transition metals and their alloys. Here T0 =0.66K, A =1/5K1/2, λ is electron-phonon coupling constant, is the average phonon frequency and ω0 the high frequency cutoff of the effective phonon spectrum a2F(ω). The values of 2△0/(kBTc) of disordered and amorphous superconductors which have the known parameters of the phonon spectrum have been calculated. Agreement with experiment is within a few percent. We show that the amorphous superconductor of non-transition metals and alloys is either a strong coupling superconductor which has a 2△0/(kBTc) valve much larger than the BCS theory value or a weak coupling superconductor which has a considerable smaller one than the BCS theory value.
THE STRUCTURE AND SUPERCONDUCTIVITY IN THE PROCESS OF PHASE TRANSITION IN InSb FILMS CONDENSED AT LOW TEMPERATURE
1986, 35 (3): 403-407. doi: 10.7498/aps.35.403
The structure changes and their effect on superconducting phase transitions in the process of the phase transitions in InSb films condensed at low temperature are studied. A series of new results are found through the experiment of X-ray diffraction. The conductivity and corresponding Tc are explained in this article. It is shown that the second peak of eleetroconductance is caused by layers conducting mechanism of hexagonal (InSb)H.
1986, 35 (3): 408-412. doi: 10.7498/aps.35.408
We have discussed theoretically the interface structures of superlattices made of materials with different lattice structures. At first, the ideal matching conditions are obtained for the rigidlattiee model. On the basis of these, we have investigated the regions of parameters, where the practical materials may be fitted into these ideal matching conditions through some elastic strains. As an example, the phase diagrams of the interface structures for fee (111)-bee (110) superlattice have been calculated.
1986, 35 (3): 413-418. doi: 10.7498/aps.35.413
For the general case (either paraxial approximation or non-paraxial situation) and the case of discrete sample, we show that any given linear transform can be achieved by dual phase-amplitude mask optical system. Using feed-back iteration approach, the specific formulae to design the phase-amplitude distributions of dual masks are obtained. Adopting four dimension al Walsh transfom in three orders as examples, we have given the phase-amplitude distributions for masks and evaluated the approiach degree. These results axe relatively satisfactory. It shows the present proposal is reasonable and useful.