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Volume 7 Issue 12
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Original Articles
INTERIOR MEHRA-LIKE SOLUTION IN HIGHER DIMENSIONS
WANG Xingxiang
Chin. Phys. Lett. 1990, 7 (12): 529-532 .  
Abstract   PDF(pc) (38KB) ( 340 )
A new spherically symmetric interior solution in higher dimension is presented by specifying mass density, i.e. k2ρ = A + Br2. The solution includes the Schwarzschild-like solution as a special case and can reduce to the interior Mehra solution when the number of dimension is four.
SCALING EXPONENT FOR 3-STATE POTTS MODEL ON 3-DIMENSIONAL RANDOM TRIANGLE LATTICE
CHEN Tianlun, HUANG Wuqun
Chin. Phys. Lett. 1990, 7 (12): 533-536 .  
Abstract   PDF(pc) (50KB) ( 273 )
An optimal Monte Carlo renormalization group method is applied to 3- state Potts model on 3-dimensional random triangle lattice. The scaling exponent v of the first order phase transition of this model has been obtained. In the disorder phase v = 0.369(±0.044), yT = l/v = 2.71(±0.32), in the order phase v= 0.393(±0.048), yT = 2.54(±0.31). They approximate to the prediction of the scaling theory.
SURFACE SELF-DIFFUSION ANISOTROPY OF TUNGSTEN ATOMS ON W(112) PLANE
GONG Yunming
Chin. Phys. Lett. 1990, 7 (12): 537-540 .  
Abstract   PDF(pc) (55KB) ( 434 )
Surface self-diffusion anisotropy of tungsten on W(112) plane has been measured along (||) and across (⊥) channels existed on this plane by using the field emission fluctuation method in two forms of the probeholes. In the round probehole the thermal activation energy E=13.0kcal, and the prefactor of the surface self-diffusion coefficient D0 = 4.8x10-7 cm2 s-1; in the long narrow rectangular slit, E(||) =13.2kcal, D0(||)= 7.1x10-7 cm2 s-1 and E (⊥) =6.2kcal, D0(⊥) =1.8X 10-9 cm2 s-1 at T=500~700K. The experimental data suggest that a W atom diffusing across channels should not climb over the channel wall, which would certainly require a much higher activation energy, but instead, displace an atom in the wall. This process requires a much smaller activation energy; however, since it involves concerted motion of at least two atoms, it will also have a much smaller prefactor.

DETERMINATION OF FINE STRUCTURE TRANSITION CROSS SECTIONS OF Rb(72D) ATOMS INDUCED BY COLLISIONS WITH MOLECULES OF H2 OR CO
SUN Xianping, LIU Zidong, LI Senlin
Chin. Phys. Lett. 1990, 7 (12): 541-543 .  
Abstract   PDF(pc) (42KB) ( 376 )
The cross sections for fine-structure transition (FST) of Rb(72D) atoms induced by collision with molecules of H2 and CO have been experimentally determined by the method of selective stepwise excitation of Rb atoms and observation of the resulting fluorescence. The cross sections (in units of 10-14cm2) for Rb(72D) - H2 are σ*fs(72D5/2 → 72D3/2) = 0.16±0.03, σ*`fs(72D3/2 →72D5/2) = 0.24 ±0.05, for Rb(72D)-CO: σ*fs = 0.10±0.06 and σ*`fs = 0.15±0.09. The cross sections σ*tr for transfer out of the 72D doublet were also determined.


DEPOLARIZERS MADE OF CHALCEDONY
LI Yi, SU Xiyu, Li Chengxiang, FU Jixiao
Chin. Phys. Lett. 1990, 7 (12): 544-547 .  
Abstract   PDF(pc) (43KB) ( 346 )
We report depolarizers made of a new kind of scattering depolarization material, named chalcedony, which can make the polarization directions of the photons in the linearly polarized incident light randomly distributed. With a piece of the chalcedony to a thickness of 3mm, a total transmission higher than 50% and the linear polarization degree tending to zero can be easily obtained.
AMPLIFICATION OF TUNABLE HIGH REPETITION PICOSECOND PULSE FROM SHORT CAVITY DYE LASERS
ZHU Lei, QIAN Liejia, ZHANG Guiyan, LIN Fucheng
Chin. Phys. Lett. 1990, 7 (12): 548-551 .  
Abstract   PDF(pc) (46KB) ( 361 )
It is reported here that synchronous amplification and tuning of 30ps pulses from the short cavity dye laser pumped by copper bromide laser have been achieved by a dye amplifier-dispersion system. It can be tuned continuously from 570 to 590nm to be almost Fourier-transform limited when using Rh6G solution.
GENERATION OF STOKES WAVE IN OPTICAL FIBER SOLITON PROPAGATION
ZHAO Yang
Chin. Phys. Lett. 1990, 7 (12): 552-555 .  
Abstract   PDF(pc) (44KB) ( 418 )
Considering cross-phase modulation, fiber loss and pulse walk off, the author studied analytically the evolution of the Stokes wave pumped by elementary soliton propagating in optical fiber. Cross-phase modulation leads to the periodical amplification of the Stokes wave. There exists a maximum amplification distance due to soliton fiber loss.
NEW ORGANIC SYSTEM FOR PHOTON-GATED PERSISTENT SPECTRAL HOLE BURNING
WANG Duoyuan*, HU Lingzhi*, HE Huizhu*, XIE Jie*, ZHANG Junyi*, ZHAO Lizeng, ZHANG Xiulan, ZHANG Dongxiang, MI Xin, NIE Yuxin, YE Peixian
Chin. Phys. Lett. 1990, 7 (12): 556-559 .  
Abstract   PDF(pc) (49KB) ( 451 )
We report a new system of organic materials for photon-gated persistent spectral hole burning by donor-acceptor electron transfer: a tetrabenzoporphyrin derivative as donor and one of several aromatic cyanides as an acceptor in a poly (methyl methacrylate) (PMMA) host matrix. Up to 500% deep spectral holes in transmission were burnt and appeared very high hole burning efficiency.
DIFFERENCE-EQUATION APPROACH IN EVALUATING ATOMIC CORRELATION FUNCTIONS OF STEPPED SURFACES
HUANG Li, ZHAO Lihua
Chin. Phys. Lett. 1990, 7 (12): 560-563 .  
Abstract   PDF(pc) (49KB) ( 349 )
The difference-equation approach is applied to evaluate the atomic pair correlation function analytically and exactly for a three-level system with steps distributed randomly on the surface. A simple closed-form solution is obtained for the angular distribution of the intensity diffracted from this surface.
RADIATION EFFECT ON Bi(Pb)-Sr-Ca-Cu-O BY 35MeV PROTON IRRADIATION
YU Jinnan, WANG Yuzhu, GAO Zhongcai*, CHEN Yiren, SHI Yuemei
Chin. Phys. Lett. 1990, 7 (12): 564-567 .  
Abstract   PDF(pc) (50KB) ( 413 )
Specimens of Bi(Pb)-Sr-Ca-Cu-O are irradiated by 35MeV proton at 70K, the critical zero-resistance temperature increases with the proton fluence within the range (2.21 x 1013 ~ 3.54x 1014 p/cm2). This increase is about 5K at 3.54 x1014p/cm2 for specimen-1 and is about 10K at 4.42X 1013 p/cm2 for specimen- 2. The critical current at 107K for specimen-1 increases by a factor of five. An endothermic reaction appears in the annealing process.
GROWTH OF BETA-BARIUM METABORATE SINGLE CRYSTAL FIBERS ALONG THE PHASE MATCHING DIRECTION
HOU Jianguo, TANG Dingyuan, CHEN Chuangtian, YE Linghua*, CHEN Jiqin*, DING Zuchang*
Chin. Phys. Lett. 1990, 7 (12): 568-570 .  
Abstract   PDF(pc) (75KB) ( 504 )
High optical quality single crystal fibers of β-BaB2O4(BBO), an important nonlinear optical material, were grown along the second-harmonic generation phase matching direction by the laser heated pedestal growth method. The effects of various growth parameters, especially growth rate, on growth stability and fiber quality were investigated. It was found that 0.25mm/min is the suitable growth rate which can reduces the harmful effects of growth anisotropy and constitutional supercooling on fiber quality.
11 articles