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Volume 6 Issue 4
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Original Articles
A NEW SOLUTION OF CHIRAL N=2, D=10 SUPERGRAVITY
JU Guoxin, WANG Mian
Chin. Phys. Lett. 1989, 6 (4): 145-148 .  
Abstract   PDF(pc) (44KB) ( 358 )
We combine the Freund-Rubin (FR) type ansatz with the nonlinear sigma model, a new solution of the chiral N=2, D=10 supergravity compactified on manifold M4 x N4 x H2 is obtained. Its properties are discussed.
MONTE CARLO STUDY OF SU(2)XSU(2) CHIRAL MODEL WITH MIXED ACTION ON THE 2-DIMENSIONAL RANDOM LATTICE
ZHANG Jianbo, YING Heping, LI Wenzhou
Chin. Phys. Lett. 1989, 6 (4): 149-152 .  
Abstract   PDF(pc) (51KB) ( 409 )
We analyzed the SU(2)x SU(2) chiral model with mixed fundamental-adjoint action on the 2-dimensional(2-D) random lattice by using Monte-Carlo (M-C) simulation. The results show that the model behaves like the mixed SU(2)xSU(2) chiral model on the 2–D regular lattice, but the character of the phase transition seems to be different.

ONE FIRE-BALL
WANG Zhengzhi
Chin. Phys. Lett. 1989, 6 (4): 153-156 .  
Abstract   PDF(pc) (38KB) ( 339 )
In the case of k=l, √s ≥√s0 =l.847x108x (l ± 0.397)Gev and at the constant temperature and volume, the overage particle number in each fire-ball n and the rapidity y can be related to the following equation 1/n.dn/dy=1/ch2y. (3)/F(Mc2/kBT).exp(-Mc2/kBT.chy)[1+ Mc2/kBT.chy+1/2(Mc2/kBT.chy)2] and in the inelastic case where √s ≥√s0 , the cross section σin ~ constant.


A NEW METHOD FOR PROFILING BORON BY NUCLEAR REACTION ANALYSIS
LU Xiting*, XIE Yuan*, ZHENG Zongshuang, JIANG Weilin, LIU Jiaru
Chin. Phys. Lett. 1989, 6 (4): 157-160 .  
Abstract   PDF(pc) (43KB) ( 393 )
By studying the relative excitation curve of 11B ( p , α0 ) 8Be , we found that there is a wide platform (~100KeV) near the Ep=2.62Me V peak, which can be used to profile boron. A brief comparison between the new method and that of 11B ( p , α1 ) 8Be* reaction has been given.
LIFETIME MEASUREMENT FOR THE (23537)°9/2 LEVEL OF NdII USING THE COLLINEAR ION BEAM-LASER INTERACTION
LU Fuquan, WU Songmao, SHI Wei, SHI Peixiong, YANG Jianjun, SONG Linggen, TANG Jiayong, YANG Fujia
Chin. Phys. Lett. 1989, 6 (4): 161-164 .  
Abstract   PDF(pc) (48KB) ( 344 )
The collinear fast ion beam-laser spectroscopy has been used to measure the radiative lifetime of the (23537)°9/2 level of the rare earth ions NdII. The measurement was carried out by the interaction between the 30keV NdII ion beam and tunable collinear dye laser which resonantly excited a metastable level to the (23537)°9/2 level, and by the observation of its time-resolved decay downstream. The lifetime value obtained from a fit program was 27.6±0.9ns . The result may provide a possibility of determining the unknown configuration of the (23537)°9/2 level.
A COMPARISON OF EMISSION CROSS SECTIONS IN COLLISION BETWEEN Ar2+ AND Ne OR He
YANG Feng, LEI Ziming, LIU Jiarui, PAN Guangyan, YU Dehong, SUN Xiang
Chin. Phys. Lett. 1989, 6 (4): 165-168 .  
Abstract   PDF(pc) (48KB) ( 342 )
There are three channels of excitation in collisions between Ar2+ and Ne or He, the first is double-electron capture into excited states, the second is single-electron capture into excited states and the third is direct excitation of target by the impact of incident ion. The emission cross sections of ArI, ArII, NeI, NeII, HeI and HeII lines have been obtained and compared. The emission cross sections of Ar2+ +Ne collision system is much larger than that of Ar2+ +He collision system.
AMORPHOUS PHASE FORMATION IN CARBON-IMPLANTED NICKEL
XU Minghua, S.Patu, WANG Zhongguang
Chin. Phys. Lett. 1989, 6 (4): 169-172 .  
Abstract   PDF(pc) (61KB) ( 474 )
Implantation 150keV carbon ions into pure nickel to a dose of 2 x 1017 ions / cm2 produced a multiple-layer structure in the implanted region. This multiple-layer consists of amorphous, Ni3C and some other metastable phases.
SOLID STATE AMORPHIZATION REACTION REACTION UNDER HIGH PRESSURE
YAN Zhihua, LI Jinfeng, WANG Wenkui
Chin. Phys. Lett. 1989, 6 (4): 173-176 .  
Abstract   PDF(pc) (46KB) ( 337 )
The solid state reaction of Ni50Ti50 multilayer under high pressure was carried out to investigate the effect of pressure on the amorphization process. Under the pressure of 20kbars amorphization reaction could not occur at 250°C while amorphous phase formed by isothermal annealing at same temperature in vacuum as well as lower pressure. It is suggested that the effect of pressure on diffusion played a predominant role, and Ni atom should diffuse into Ti layers with vacancy mechanism rather than interstitial one.
THERMOELECTRIC POWER IN SUPERCONDUCTING Bi2Sr2 Ca2 Ox CRYSTAL
YAN Shousheng, CHEN Tong, ZHANG Wenbin, ZHANG Haibo, WU Ke, TONG Litai, ZHANG Hong*
Chin. Phys. Lett. 1989, 6 (4): 177-180 .  
Abstract   PDF(pc) (61KB) ( 316 )
The thermoelectric power S of a superconducting Bi2Sr2CaCu2Ox crystal has been measured from 77K to 290K, and obvious anisotropy has been observed. The values of S in a-b plane are negative and small, and S in c-axis are positive. If the semiconductor-like behavior of R(T) is intrinsic in c direction, supposing the existence of metallic links between Cu-O planes caused by defects in crystal, the behaviors of S(T) and R(T) in c direction of our sample could be understood.
PHOTOINDUCED DEFECT OPTICAL ABSORPTION IN a-Si:H
WU Lei, HAN Daxing
Chin. Phys. Lett. 1989, 6 (4): 181-184 .  
Abstract   PDF(pc) (49KB) ( 373 )
The photoinduced defect absorption in a-Si:H excited by bandgap light was studied. Energy position of light-induced metastable defects is different from that of native dangling bonds.
THE LINEAR TEMPERATURE BEHAVIOR OF RESISTMTY AND OXYGEN STOICHIOMETRY IN YBa2Cu3O7-x
ZHU shining, ZHANG Xingkui, XU Ziran, WANG Hao, XIA Hua
Chin. Phys. Lett. 1989, 6 (4): 185-188 .  
Abstract   PDF(pc) (55KB) ( 358 )
By employing a gettered annealing technique, we studied the relationship between the resistivity ρ(x, T) (20°C≤ T≤ 30°C) and oxygen content in the high-Tc superconductor YBa2Cu3O7-x. ρ(x, T) is approximately linear for 0.0≤ x ≤0.6, and both the slope dρ/dT and the residual resistivity increase continuously decreasing oxygen content. A qualitative analysis is given.
CONTRIBUTION OF Sm3+ ION TO THE MAGNETOCRYSTALLINE ANISOTROPY IN SmTiFe11 COMPOUND
PEI Xiedi*, YANG Yingchang, ZHA Yuanbo, SUN Hong, KONG Linshu
Chin. Phys. Lett. 1989, 6 (4): 189-192 .  
Abstract   PDF(pc) (54KB) ( 408 )
The magnetocrystalline anisotropy of SmTiFe11 has been studied. In addition to experimental investigations, the contribution of Sm3+ ion to the magnetocrystalline aniso-tropy of SmTiFe11 has been calculated using the single ion theory. The effect of the first excited state of Sm3+ has been taken into consideration in the calculations, and the calculated results are consistent with the experimental data.
12 articles