Vol. 39, No. 7 (1990)
1990-04-05
GENERAL
1990, 39 (7): 1-7.
doi: 10.7498/aps.39.1-4
Abstract +
The algebras of meromorphic vector fields and the bases of meromorphic λ-differentials with multipoles are constructed explicitly on general genus Riemann surfaces. For Riemann sphere the central extension of the algebra is also given.
1990, 39 (7): 8-14.
doi: 10.7498/aps.39.8
Abstract +
The Gaussian effective potential of the double sine-Gordon model in n + 1 dim ensions is computed. Within the Gaussian approximation, we prove that the model is trivial for n ≥ 3 and there exists a Coleman phase transition point for n cr=(n+2π(n+1)/2(α1R+α2R/4)(3-n)/2)/(Γ(1/2(3-n))(α1R+α2R/16)).
1990, 39 (7): 15-18.
doi: 10.7498/aps.39.15
Abstract +
In this article, we found that scaling properties of the cluster are changed by uniform external fields, when we adopted the model of diffusion-limited aggregation without branching to simulate the irrevesible aggregation of small particles in uniform external fields. The relationship between Hausdorff dimension D of the cluster and uniform external fields has been found: D = 2.50F0.37exp(-1.08F) + 1
1990, 39 (7): 19-27.
doi: 10.7498/aps.39.19-2
Abstract +
According to the computer simulation results for diffusion-limited aggregation in two-dimensional Euclidean space, we give a discussion about some formula for the screening behavior introduced by Muthukumar, Tokuyama, Hentschel and Mutsushita separately. We show that these formula give a large disaggreement with our computer simulation results for a finite system. Then, through the analysis of the process of aggregation by random walk particles, we obtain a equation for the screening behavior that agrees with the simulations in this paper. Finally, we find that the formula introduced by Muthukumar is correct if the aggregate is sufficiently large.
1990, 39 (7): 28-34.
doi: 10.7498/aps.39.28
Abstract +
We study continuous time random walk with the waiting time distribution having long-time tail t-α, 0 <α< 1. The fractal time behavior of the hopping event set is treated in a systematic and rigorous way. We construct a dynamic model which shows the fractal time behavior. The expertmenu of dispersion diffution in amorphous systems are well explained by our theory.
1990, 39 (7): 35-39.
doi: 10.7498/aps.39.35-2
Abstract +
In this article, we propose a parabola approximation to the theory of bifurcation. From that the process of instability to bifurcation, the effect of stubilization after bifurcation, the limit to wards chaos can be made dear and the Feigenbaum number can be caluclated.
1990, 39 (7): 40-47.
doi: 10.7498/aps.39.40-2
Abstract +
This paper, based on the formulation of the entropy production of mixed optical bistable systems (OBS)[5] is devoted to the demonstration of the theorem of minimum enropy production.
ATOMIC AND MOLECULAR PHYSICS
1990, 39 (7): 48-53.
doi: 10.7498/aps.39.48
Abstract +
We report here the measurment and results of the odd parity autoionizing spectra of Ybl by the laser multistep excitation technique. More then thirty autoionizing levels were obtained. Our results were compared with the previous ones obtained by one photon absorption and electron collision excition technique.
CLASSICAL AREA OF PHENOMENOLOGY
1990, 39 (7): 54-58.
doi: 10.7498/aps.39.54-2
Abstract +
In this paper, the higher-order squeezing of a single mode light field state ｜ψ>=α｜0>+β｜m>(m>2) is studied. When m is even integral,we find that it exhibits arbitary higher-order squeezing except second order squeezing. But the higher-order squeezing and antibunchinf; do not appear simultaneously- Thus, we come to a conclusion that higher-order squeezing is a new nonclassicl effect of light field which is independent of second order squeezing and antibunching.
1990, 39 (7): 59-65.
doi: 10.7498/aps.39.59-2
Abstract +
A statistical numerical simulation method is proposed, and by which the accumulation of phase fluctuation and the spectral linewidth in semiconductor lasers are investigated theoretically. In the case of single mode, the result is quite in agreement with that by small signal approximation instead of being its 4 times. In the case of nearly single mode, the linewidth of the main mode is increased somewhat but not too seriously by the side mode. The overestimation and its cause of the results obtained by a Monte Carlo method used by other author recently is noted, and a power independent linewidth component of the side mode of the order of 100 MHz agreed with experiment is obtained where the small signal approximation is not applicable.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
1990, 39 (7): 66-76.
doi: 10.7498/aps.39.66
Abstract +
We have studied the relaxation of IIIA-VIA and IIB-VIA compounds AB (110) and AB (1010) surfaces with LEED, and found that the best agreement between theory and experiment occurs in such a sturcture, in which the B atoms are tilted outward and A atoms are tilted inward, with an angle of rotation ω, keeping the bond length at surface A-B unchanged, and the first atomic surfaces layer distances d1=0.610-0.810? [for IIIA-VA (110)] , 0.536-0.825?[for IIB-VIA (110)] and 0.633-1.060?[for IIB-VIA (1010)] and the second surfaces atomic layer distances d2 = 1.300-1.610?[for IIIA-VA(ll0)] , 1.430-1.700?[for IIB-VIA (110)] and 0.820-0.930?[for IIB-VIA (1010)] and third one d3 = 1.410-2.440?[for 1I1A-VA (110)], 2.020-2.250?[for IIB-VIA (110)] and 1.910-2.440?[for IIB-VIA (1010)] . For this structure the relaxation susceptibility a are: 0.24±0.02[for IIIA-VA (110)], 0.25±0.02 [for IIB-VIA (110)] and 0.33 ±0.03 [for IIB-VIA (1010)].
1990, 39 (7): 77-80.
doi: 10.7498/aps.39.77
Abstract +
The interaction between hydrogen and irradiated defects in iron was studied. Different kinds of complexes of hydrogen and defects would form if hydrogen was trapped by the defects. During aging at various temperatures, it was observed that interstitial-type loops formed above 300℃, vacancy-type loops formed above 450℃ and voids formed at 520℃. We consider that such complexes as H-I or H-Is, H-V and H-Vs result in interstitial-type loop, vacancy-type loop and void, respectively.
1990, 39 (7): 81-87.
doi: 10.7498/aps.39.81
Abstract +
In this paper, the gauge field theory of crystal defects is applied to analyse the characteristics of moving screw dislocation. The dynamic equations of screw dislocation are solved under certain gauge condition and the stress fields of uniformly moving screw dislocation are obtained. When K = μ/s (x is the coupling constant) approaches zero, the form of stress fields tends to be the same as that of uniformlymoving Volterra dislocation, but the limiting velocity happens to be 21/2c. When the velocity of this dislocation is zero, the stress are the same as that of Volterra dislocation at rest. Finally, the results are discussed in brief.
1990, 39 (7): 88-94.
doi: 10.7498/aps.39.88
Abstract +
In this paper, implantation of indium atoms into silicon forming pn juction by Nd-YAG pulse laser irradiation was reported. The indium depth profile in silicon has been determined by secondary ion mass spectrscopy (SIMS) and Rutherford backscatting spectroscopy (RBS). The results can be ascribed to a qualitative model for the physical process of implantation indium in 20ns pulse laser irradiation. Namely, if the laser energy density exceeds a certain threshold, there exist two parts at the surface layer of silicon, silicon-indium molten mixture and liquid state silicon. But only the liquid state silicon layer exists at the surface if the laser energy density does not reach that threshold. The pn juction has good properties revealed by means of I-V and C-V measurements. The results of deep level transient spectroscopy (DLTS) show that there are two kinds of defects in pn juction. One kind of the defects (E1) disappears at 600℃, 60s in rapid thermal annealing (RTA) and the study shows that the defect E1 may be the impurity-vacancy complex. The other defects E2 would not disappear in RTA and may be related to the dislocations.
1990, 39 (7): 95-100.
doi: 10.7498/aps.39.95
Abstract +
The effects of the space and time disorder on the survival probability of tunneling states and the relaxation time are analysed with the theory of continuous-time random walk (CTRW) on fractals. The infrared divergence response (IDR) theory is generalized and made possible to explain the relaxation phenomena in metal glasses.
1990, 39 (7): 101-105.
doi: 10.7498/aps.39.101-2
Abstract +
An amorphous phase of Ni/Ti bilayer system is formed by solid state reaction and inn beam mixing. The results of TEM cross sectional photograph show that the diffusion results in the amorphous phase formation, Ni is the dominate diffusion species, and the ion beam bombardment enhances Ni diffusion.
1990, 39 (7): 106-111.
doi: 10.7498/aps.39.106
Abstract +
Positron lifetime spectra have been measured as a function of temperature from 30 K to 150 K in condensed methane. In solid phase, the positronium (Ps) formation in free volume and the Ps yield of 27% were observed. The sigmoidal variation of o-Ps lifetime with temperature was interpreted by Ps trapping in the thermally activated defects. The activated energy Ea = 0.10±0.02 eV was derived in terms of Ps trapping model. In liquid methane with saturated vapor pressure, the results that o-Ps lifetime is 5-7ns and Ps formation probability is 36% indicate the Ps bubble formation. The temperature dependence of the bubble size and surface tension were estimated.
1990, 39 (7): 112-118.
doi: 10.7498/aps.39.112
Abstract +
The solid phase epitaxy processes of (100) Si implanted at 77K by 180 keV, 1×1014/cm2 P2+ and 90keV, 2×1014/cm2 P+ have been investigated by using time resolved reflectivity (TRB), Rutherford back scattering and channeling (RBS/C), and cross sectional transmission electron microscopy (XTEM). The difference of TRR spectra between P2+ and P2+ implanted samples annealed at 550℃ is due to the difference in implantation damage of the two different implants. Anomalous TRR spactra for P+ implanted sample can be explained by a model of two direction epitaxial growth from surface layer to amorphous layer and from substrate to amorphous layer.
1990, 39 (7): 127-133.
doi: 10.7498/aps.39.127
Abstract +
Titanium films are deposited on Si wafers by electron-beam evaporation in vacuum, the base pressure of the system is 10-7 Torr. Solid phase reaction results through rapid thermal annealing. After annealed at 540-600℃, two metastable phase diffraction peaks of Ti5Si4 are observed in X-ray diffraction (XRD) pattern. Prolonging the annealing time, the first nucleated phase Ti5Si4 remains unchanged until titanium is completely consumed, then it transforms into a stable phase TiSi2. When the annealing tcmpeiature is above 640℃, a stable phase TiSi2 is formed. The researches of sheel resistance and Raman scattering give the results which are in good agreement with XRD. The two Raman peaks at 207 and 244 cm-1 are characteristic Raman peaks of TiSi2, but the other three Raman peaks at 270, 297 and 341 cm-1 are likely attributed
1990, 39 (7): 158-162.
doi: 10.7498/aps.39.158-2
Abstract +
The two-phase structure invariants for the crystal, ψ2=ψH+ψH, are calculated, and the statistical distribution of negative Ψ2 with |E| is obtained. The results for this crystal show that Hauptman's probabilistic formula (1) may reliably determine the signs of Ψ2 as long as their |E| values are not too small in practical use. The computational results for other 5 crystals, C18H24NO4 and its derivatives, also support the above conclusion
GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS
1990, 39 (7): 163-166.
doi: 10.7498/aps.39.163-2
Abstract +
The dynamics of non-singular spherical black hole suggested by Gonzalez-Diaz is investigated. We show that it's matter configuration is in peculiar equilibrium and unstable. It's formation is seldom and it is liaule to transit to a normal black hole.
