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Volume 5 Issue 1
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Original Articles
RAMAN SPECTRA OF MONOCLINIC NEODYMIUM-ALUMINUM BORATE
Kim Ha, SHI Shan*
Chin. Phys. Lett. 1988, 5 (1): 1-4 .  
Abstract   PDF(pc) (41KB) ( 491 )
The Raman spectra of monoclinic NdAL3(BO3)4(NAB) have been recorded and interpreted. A factor group analysis of the NAB space group shows that there are 25Ag and 26Bg Raman-active modes, and 34Au and 35Bu IR-active modes. A discussion of the assignment of the individual Raman lines was given. The predicted factor group splittings for the internal modes of BO3 anion were observed and interpreted.
MORPHOLOGY AND STRUCTURE OF HIGH Tc YBaCuO THIN FILMS
WANG Huisheng, LI Lin, ZHAO Bairu, LU Yong, SHI Yinhuan, ZHAO Yuying, YUAN Caiwen, GAO Ju
Chin. Phys. Lett. 1988, 5 (1): 5-8 .  
Abstract   PDF(pc) (92KB) ( 310 )
Thin superconducting films of YBa2Cu3O7-Δ have been prepared by magnetron reactive sputter deposition and subsequent heat treatment. The composition of the thin films has been determined by x-ray Bluorescence spectrum analysis, the structure by x-ray diffraction, and the morphology by scanning electron microscope. The results indicated that the crystallization process of the thin films on different substrates are markedly different. Best results are obtained on film deposited on SrTiO3 substrate, however, there still exists some non-superconducting phase at the grain boundaries making the superconducting phase weakly linked.

OPTICAL DIFFRACTION ON SIERPINSKI CARPET
JIN Guojun, FENG Bihua, FENG Duan
Chin. Phys. Lett. 1988, 5 (1): 9-12 .  
Abstract   PDF(pc) (50KB) ( 469 )
An experimental study of the optical diffraction on Sierpinski carpet is performed. The theoretical formula for diffraction intensity is derived and computer simulation is carried out in order to compare with experimentally observed diffraction pattern. The results shod that the pattern of the Fourier transform of a fractal grating is also selfsimilar and the fractal dimension may be determined with optical measurement.
THE FRAGMENT MASS DISTRIBUTION IN C+Ag COLLISIONS
LU Zhaoqi, ZHANG Xiaoze, SA Benhao
Chin. Phys. Lett. 1988, 5 (1): 13-16 .  
Abstract   PDF(pc) (41KB) ( 352 )
The mass yield distribution in C+Ag collision has been calculated . Not only the data are reproduced very well, but also a power law A is established for light fragments. In addition, the impact parameter dependence of the number of fragments and the evaporation neutrons as well as the fragment mass distribution for different impact parameter is given.
MESON-PROTON ELASTIC SCATTERING AT 250 GEV/C
Mohammad Saleem, Haris Rashid, Fazal-e-Aleem*
Chin. Phys. Lett. 1988, 5 (1): 17-20 .  
Abstract   PDF(pc) (45KB) ( 441 )
Very recent measurements of π+p and k+p elastic scattering at 250GeV/c have been explained by using the generalised Chou-Yang model. Dips are predicted to occur at -t=3.63 and 4.36(GeV/c)2 respectively.

OBSERVATION OF LEAKY SAW AND OTHER ACOUSTIC MODES ON 49°Y-ROTATED LiNbO3 BY OPTICAL DIFFRACTION METHOD
WU Wenqiu, XU Jian bin, ZHANG Shuyi
Chin. Phys. Lett. 1988, 5 (1): 21-24 .  
Abstract   PDF(pc) (47KB) ( 365 )
The propagation properties of LSAW and SAW as well as acoustic bulk waves on the substrate of 49°Y-rotated LiNbO3 excited by IDT are investigated by Schaefer-Bergmann diffraction technique and electrical method. The inverse phase velocity curves in the propagation plane are obtained both experimentally and theoretically. The existence of LSAW in some directions on the substrate has been verified.
LASER-IMPLODING DYNAMICS OF GLASS MICROBALLOONS BY MULTI-FRAME X-RAY SHADOWGRAPHY
LIN Zunqi, LI Jiaming*
Chin. Phys. Lett. 1988, 5 (1): 25-28 .  
Abstract   PDF(pc) (44KB) ( 390 )
X-ray shadowgraphs at four distinct times for each implosion of the glass microballoon illuminated by high power laser have been obtain. Ultilizing the anomalous scattering of the backlighting X-rays by judiciously selecting the photon energies, the motion of the innerwall of the imploding glass microballoon can be directly diagnosed.

THEORETICAL STUDY OF MOLYBDENUM CHEMISORPTION ON Si (111) AND Si(100) SURFACES
TANG Shaoping, ZHANG Kaiming, XIE Xide
Chin. Phys. Lett. 1988, 5 (1): 29-32 .  
Abstract   PDF(pc) (48KB) ( 358 )
The chemisorptions of Mo on both Si(111) and Si(100) surfaces are investigated by the DV-Xα-SCF method. The results show that after overcoming a certain energy barrier the adsorbate Mo can penetrate the surface to form adamantine structure. The electronic states of chemisorption are calculated and compared with experimental results.
THE EFFECTS OF CARBON SEGREGATION AND ARGON ADSORPTION ON THE ADHESIVE BEHAVIOR OF Fe-A1 COUPLE
SUN Jiansan, QI Zhenzhong, LIU Ling, YAO Weiguo
Chin. Phys. Lett. 1988, 5 (1): 33-36 .  
Abstract   PDF(pc) (38KB) ( 318 )
The effects of carbon segregation and argon adsorption on adhesive interaction between Fe-A1 contact were investigated experimentally. The presence of argon atoms and carbon segregation could reduce the adhesive interaction markedly.
TWO-DIMENSIONAL PHASE TRANSITION IN CHEMISORPTION SYSTEM - A MONTE CARLO SIMULATION
HU Zipu, LI Jia
Chin. Phys. Lett. 1988, 5 (1): 37-40 .  
Abstract   PDF(pc) (48KB) ( 345 )
A simple 12-4-3 exp potential model is proposed to describe the interaction between adatoms. Two dimensional phase transition is studied by Monte Carlo simulation with lattice gas model in which the third nearest neighbor interaction is considered. Both the ( √3 x √3 ) -30°and the (2x2) structure are obtained under different coverages and temperatures. A limited T-θ phase diagram which is similar to that from experiment is obtained.
STUDY OF TRANSIENTS IN DIFFUSION PROCESS
WU Xizhen, FENG Renfa, ZHUO Yizhong
Chin. Phys. Lett. 1988, 5 (1): 41-44 .  
Abstract   PDF(pc) (42KB) ( 379 )
The transient behaviour in approaching to equilibrium for a diffusion system is described by means of Fokker-Planck equation and particular attention is paid to the overshooting of probability current at high temperatures.
COSMIC STRINGS AND THE FORMATION EPOCH OF LARGE SCALE STRUCTURE
GAO Yu
Chin. Phys. Lett. 1988, 5 (1): 45-47 .  
Abstract   PDF(pc) (32KB) ( 421 )
The formation of galaxies, clusters and superclusters (SCs) is discussed based on a cosmic string model, and the constraints are given for the corresponding loops which form these structures by the accretion of the loops. Only those loops that came into horizon after teq (the time of equal matter and radiation) may be the seeds of clusters and SCs.
12 articles