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Volume 9 Issue 12
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Original Articles
Even and Odd Q-coherent State Representations of the Q-deformed Heisenberg-Weyl Algebra
WANG Fabo, KUANG Leman*
Chin. Phys. Lett. 1992, 9 (12): 629-232 .  
Abstract   PDF(pc) (151KB) ( 505 )
We construct explicitly even and odd q-coherent states. These q-coherent states are introduced in terms of the q-functions defined in the paper. It is shown that the even and odd q-coherent states form a kind of representations of the q-deformed Heisenberg-Weyl algebra which is realized in the form of matrix q-differential operators in the even and odd q-coherent state space. We also analyse some different between the even and odd q-CSs and the usual even and odd CSs.
Fermion System with Quantum Group Symmetry and Usual Fermion Realizations of S1q(2)
SUN Changpu, LI Jianming*
Chin. Phys. Lett. 1992, 9 (12): 633-636 .  
Abstract   PDF(pc) (144KB) ( 347 )
The usual fermion realizations of quantum algebra slq(2) defining higher-dimensional representations are built in this letter. Using them, we construct a usual fermion system with quantum group symmetry of slq(2) as a q-deformation of the pairing correlation model in many-body problems. Its energy spectra are exactly solved out from the representation theory of slq(2).

Can Boltzmann Soliton Star Exist?
SU Rukeng*, CHEN Xuelei*, PAN Rongshi**
Chin. Phys. Lett. 1992, 9 (12): 637-639 .  
Abstract   PDF(pc) (152KB) ( 353 )
The ferrnion soliton stars suggested by Lee and Pang are extended to finite temperature. The degeneracy temperature TD above which the fermion soliton star will become a Boltzmann soliton star is given. We prove that the Doltzmann soliton star cannot exist, because it is unstable.
Measurement of Ultra-short Pulse-width by Using Noncollinear Sum-Frequency Generation
LI Ming, ZHANG Xiulan, LIU Xiang, ZHANG Dongxiang, DENG Daoqun
Chin. Phys. Lett. 1992, 9 (12): 640-642 .  
Abstract   PDF(pc) (131KB) ( 533 )
The third-order correlation function G(3) (0, T ) can be measured by using the method of noncollinear sum-frequency, by which the pulse-width of the ultr-ashort pulse light produced by modelocked laser is deduced to be 35ps. This result is the same as that by other standrd method.
Two-Photon Laser Spectroscopy of Autoionizing Rydberg Series of Atomic Tin
JIN Mingxing, DING Dajun, LIU Hang, PAN Shoufu
Chin. Phys. Lett. 1992, 9 (12): 643-646 .  
Abstract   PDF(pc) (220KB) ( 444 )
Extensive new data on the even-parity autoionization Rydberg series of neutral-tin have been observed and identified by using two-photon resonant ionization laser spectroscopy and time-of-flight detection method. Observed autoionization Rydberg series are 5pnp(3/2,1/2)1,2, 5pnp(3/2,3/2)1,2,3, 5pnf3/2[5/2]2,3, 5pnp3/2[7/2]3,4, and 5pnf3/2[3/2]1,2. The second ionization limit I2 is obtained by fitting experimental data with the Rydberg formula. It is 63483.90±1.35cm-1.
Continuous-Wave Self-Focusing and Self-phase Modulation in C60-Benzene Solution
HAN Yanong, ZHANG Weijun, DONG Fengzhong, XIA Yuxing, ZANG Wencheng, YANG Ping, GU Gang, DU Youwei, FENG Duan
Chin. Phys. Lett. 1992, 9 (12): 647-649 .  
Abstract   PDF(pc) (121KB) ( 389 )
C60-benzene solutions are used as a new type of nonlinear Medium for observing cw self-focusing of laser beams. Self-phase modulation of much low power laser beam has been observed. The response time of C60-benzene solution has been measured.
Microdynamics Behavior of Liquid Transition Metal Cu and Ni
CHEN Kuiying, LI Qingchun
Chin. Phys. Lett. 1992, 9 (12): 650-652 .  
Abstract   PDF(pc) (148KB) ( 455 )
Besed on the embedded atom method, molecular dynamics simulations have been performed on microdynamics behavior of liquid transition metal. Cu and Ni. Mean-square displacement, self-diffusion coefficient and velocity self-correlation function have been calculated. In addition, effects of many body interactions have been discussed.
The Time-Dependence Growth of Metallic Crystal Ultrafine Particles
LIU Cunye, DENG Zhaojing
Chin. Phys. Lett. 1992, 9 (12): 653-655 .  
Abstract   PDF(pc) (160KB) ( 439 )
By using x-ray diffraction technique and transmission electron microscopy the in situ growth property of metal crystal ultrafine particles(CUFP) which are deposited on the silica-substrates have been studied experimentially. It is found that the diffraction intensity and the nucleus diameter of Ag CUFP are grown with time by power-law. Thus, the changes of crystal nucleus and the structure of Ag CUFP with time shows a crystallization trend, at the same time, the in situ growth of Ag CUFP displays a self-similarity character.

Radiation Damage in bcc Metal Nb Studied by Perturbed Angular Correlation and Positron Annihilation Techniques
ZHU Shengyun, ZHENG Shengnan, LI Anli, HUANG Hanchen, LI Donghong, XU Guoji
Chin. Phys. Lett. 1992, 9 (12): 656-658 .  
Abstract   PDF(pc) (159KB) ( 427 )
9 The radiation damage induced by the reactor neutrons in body-centered-cubic metal Nb is simulated by the 81 MeV carbon irradiation to a total dose of 2.5x1016/cm2. The created radiation damage and its thermal annealing behavior are studied by positron annihilation and perturbed angular correlation techniques. The results show the existence of both mono- and di-vacancies in Nb after the irradiation. Most of the defects caused by the radiation damage disappear after annealing around 960K. The radiation damage is completely annealed at 1058K.
Kinks and Solitons in Coupled Pendulum Lattices
HUANG Guoxiang, XU Zaixin
Chin. Phys. Lett. 1992, 9 (12): 659-662 .  
Abstract   PDF(pc) (199KB) ( 1071 )
Self-localized structures in nonlinear coupled pendulum lattices are investigated by use of the method of multiple-scales under quasi-discreteness approximation. The upper cutoff and noncutoff kinks observed by Denardo et al. recently are theoretically explained qualitatively and a lower cutoff standing soliton is also predicated.
New fcc Phase Formed in Immiscible Fe-Cu System by Solid State Diffusion
LIU Baixin*, PAN Feng, TAO Kun
Chin. Phys. Lett. 1992, 9 (12): 663-666 .  
Abstract   PDF(pc) (244KB) ( 391 )
Fe75Cu25 nano-multilayers were prepared by alternative deposition of pure Fe and Cu metals and then annealed in situ in transmission electron microscopy to investigate the structural phase transformation. A new phase was formed in the Fe-Cu multilayers by interdiffusion at 820°C for about I0min and was identified to be of fcc structure with a lattice parameter of 0.854±0.005nm.
Flux Pinning in Y1-xMxBa2Cu3O7-δ(M=Gd, Eu and Sm) System
LI Jonghen*, FANG Minghu, HU Gangjin, ZHANG Xiaojun, JIAO Zhengkuan, ZHANG Qirui, ZHANG Yitong, JIN Xin, YAO Xixian
Chin. Phys. Lett. 1992, 9 (12): 667-669 .  
Abstract   PDF(pc) (178KB) ( 450 )
In this paper, the flux pinning effects in Y1-xMxBa2Cu3O7-δ(M=Gd, Eu and Sm) samples are reported. It is found that there is another pinning mechanism under higher magnetic fields in addition to that under lower fields. This pinning effect may stem from the lattice stress field resulting from the partial substitution of the rare earth elements with different atomic radii for Y.
A Novel Metal and Nonmetal Cluster Source Produced by Laser Ablation
ZHU Lei, WANG Shenyi, WANG Peinan, CHEN Kaitai, LI Yufen
Chin. Phys. Lett. 1992, 9 (12): 670-672 .  
Abstract   PDF(pc) (169KB) ( 425 )
We have developed a simple, novel cluster source with which intense beam of carbon and silver clusters were generated. The formation mechanism of the fullerene carbon clusters are discussed, and the velocity distribution of small carbon clusters was measured. The intensity distribution of silver clusters shows a distinct odd-even alternation, which agrees well with our previous theoretical predictions.
Wave Function in Quantum Cosmology of Bergmann-Wagoner Scalar-Tensor Gravitational Theory
LIU Zixin*, CHEN Xiaojia
Chin. Phys. Lett. 1992, 9 (12): 673-676 .  
Abstract   PDF(pc) (208KB) ( 356 )
The semiclassical cosmological wave function in quantum cosmology of the Bergrnann-Wagoner scalar tensor gravitational theory is given in Vilenkin approach and Hartle-Hawking approach. The initial condition for inflation is given, we show there exists an extended inflationary phase in a hopeful particular model.
14 articles