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Volume 10 Issue 7
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Original Articles
Property of Van Hove Critical Points in Fractional-Dimensional Space
YU Zhaoxian, MO Dang
Chin. Phys. Lett. 1993, 10 (7): 385-388 .  
Abstract   PDF(pc) (167KB) ( 482 )
The model of fractional-dimensional space is used to study dielectric function associated with electron interband transitions near a Van Hove critical point in anisotropic systems. Using fractional derivative spectra (FDS) method, it is found that in fractional-dimensional space only a minimum yields a symmetric Lorentzian line shape in FDS but a maximum does not.
A Bäcklund Transformation of a Kind of Nonlinear Wave Equation
HAI Wenhua
Chin. Phys. Lett. 1993, 10 (7): 389-392 .  
Abstract   PDF(pc) (174KB) ( 483 )
Applying the method of canonical, transformation, we studied the nonlinear wave equation φxx - φtt = dF ( φ ) /dφ . A Bäcklund transformation (BT) of this equation is obtained. Combining BT of this equation with the well-known BT of sine-Gordon equation (SGE), a formula of nonlinear superposition which contains some arbitrary functions of x and t has been established. This formula leads to a kind of general solution of SGE through its some known solutions. The general soliton solutions and their properties are simply discussed.

Radiation Phase Quantization and Its Application to the Transport Through a Quantum Dot Turnstile
LIU Chengyi, CHEN Qingming, LI Zaiguang
Chin. Phys. Lett. 1993, 10 (7): 393-396 .  
Abstract   PDF(pc) (172KB) ( 503 )
Following Schommers’ viewpoint on time, we give radiation time a reasonable definition. We realize the radiation phase quantization by supposing that a radiation-matter interaction process is an eigen state of radiation time operator. The successful application to the transport through a quantum dot turnstile in a radiation field leads to quantized current formula.
Split-Bin Correlation Functions for Multi-Particle Processes in PP Collisions at 400 GeV/c
WANG Shaoshun, ZHANG Jie, XIAO Chenguo, XIONG Weijun, KOU Jinchun, XIA Xiaojuan, ZHONG Yu
Chin. Phys. Lett. 1993, 10 (7): 397-400 .  
Abstract   PDF(pc) (177KB) ( 430 )
The pseudorapidity and azimuthal angle distributions for charged particle produced in pp collisions at 400 GeV/c have been measured by using the LEBC films offered by CERN NA27 collaboration. The split-bin correlation functions have been calculated. The results show that the correlations are produced by resonance-like processces.
Nuclear Interaction Radii for Light Exotic Nuclei
FENG Jun, SHEN Wenqing, MA Yugang
Chin. Phys. Lett. 1993, 10 (7): 401-404 .  
Abstract   PDF(pc) (184KB) ( 736 )
We developed a simple model to calculate the interaction radii for light neutron-rich nuclei based on Coulomb-modified Glauber model. Considering a relation of surface diffuseness of neutron distribution with the neutron separation energy of nucleus, the large increasing of nuclear interaction radii for exotic nuclei (such as 6He, 8He, 11Li, 11Be) on 12C target can be reasonably explained.
Calculation of the Energy Spectra of Atom Rb in Strong Magnetic Fields
LIU Lianjun, ZHANG Zhehua, GAO Daoneng, CAO Yaohui, HE Xinghong*, LI Baiwen*
Chin. Phys. Lett. 1993, 10 (7): 405-408 .  
Abstract   PDF(pc) (213KB) ( 537 )
The energy spectra and oscillator strength of atom Rb in strong magnetic fields are calculated. The wavefunctions obtained by an improved potential model proposed by some of us are chosen as the zero-order ones. The results show that the diamagnetic term seems to affect substantially only high Rydberg states. And there is a maximum of oscillator strength in each n-manifold, which varies with n increased.
Optical Fiber Raman Spectra of CCl4
LI Zuowei, CHANG Tiejun, SUN Xin, PEI Li, GAO Shujin*
Chin. Phys. Lett. 1993, 10 (7): 409-412 .  
Abstract   PDF(pc) (169KB) ( 479 )
Raman spectra of CCl4 is enhanced by a factor of 102-103 by means of hollow core quartz optical fiber filled with binary solution containing CCl4. The concentration of CCl4 in solution affects on Raman scattering coefficient of CC14 also on aperture angle of liquid core optical fiber. For each kind of solution filling the hollow core optical fiber there is an optimum CC14 concentration corresponding to a maximum Raman spectra of CCl4.

An Approach for Getting High GL in Recombination Soft x-Ray Laser
PENG Huimin, ZHANG Yuquan, LAN Ke, ZHANG Tanxin
Chin. Phys. Lett. 1993, 10 (7): 413-416 .  
Abstract   PDF(pc) (195KB) ( 375 )
We use computational codes for simulating laser-produced plasmas conditions the excited level populations of the Li-like aluminium ions. The optimal gain region for 3d - 4f transition is obtained and an approach for getting high gain length is suggested.
Mechanism of Low Pressure dc Breakdown in a Thermo-Cathode Gas Discharge
HU Xiwei, CHEN Yang
Chin. Phys. Lett. 1993, 10 (7): 417-420 .  
Abstract   PDF(pc) (201KB) ( 536 )
A theory about the dc breakdown process of a gas discharge with thermocathode in a very low pressure (10-2 Pa) is provided. The mobility of ions due to ion-neutral charge exchange collisions is mainly responsible for the space cumulative effect of positive charges and the formation of the virtual anode. A numerical result for the breakdown process of the argon gas discharge is given.
Radial Ion Flux Induced by Inhomogeneous Wave Power Deposition
LIU Caigen, GAO Qingdi
Chin. Phys. Lett. 1993, 10 (7): 421-424 .  
Abstract   PDF(pc) (173KB) ( 497 )
The enhancement of radial ion transport induced by spatially inhomogeneous rf power deposition is studied during ion cyclotron resonant heating in a tokamak. It is shown that the magnitude of this ion flux is dependent on the inhomogeneous factor F and its velocity derivative ∂F/∂v. In the special power deposition cases, this radial flux is presented.
Theoretical Calculation of Delayed Radiation Induced Conductivity in Electron Beam Charged Polymer Foils
XIE Xishun, HUANG Xiaoqin*
Chin. Phys. Lett. 1993, 10 (7): 425-428 .  
Abstract   PDF(pc) (135KB) ( 569 )
In this paper, We present the result of theoretical calculation of delayed radiation induced conductivity (DRlC) in charge free neutral polymer foils, which are irradiated by impenetrable electron beam. If a single trap level and a constant charge distribution are supposed in the irradiated region, within a very short time, DRIC of a charged film is found to vary hyperbolicly. It is just as that of charge free neutral material. But when t is infinite, the electrons in the conduction band of a charged film do not decay to zero. The DRIC will change exponentially for larger time.
Peak Effects in EuBa2Cu3Oy Crystal Prepared by Melt-Textured Growth Method
WEI Chongde, LIU Zunxiao, CAN Zizhao, REX Hongtao*, XIAO Ling*, HE Qing*
Chin. Phys. Lett. 1993, 10 (7): 429-432 .  
Abstract   PDF(pc) (182KB) ( 464 )
The magnetization curves of EuBa2Cu3Oy crystal prepared by melt-textured growth method were measured from 1.5 to 87K up to field 7.5T for H || C and H ⊥ C. Peak effects were observed at 60, 70 and 73K for H || C, and 70, 73 and 77K for H ⊥ C. It is shown that the magnetic field Hp at which the magnetization or critical current reach their extremum is approximately independent of temperature lire and the peak erects observed can be explained by matching effects.
Anticrossing Due to Resonant Coupling of Hole Levels in Asymmetric Coupled- Quantum- Wells
XU Shijie, JIANG Desheng, LI Guohua, ZHANG Yaohui, LUO Jinsheng
Chin. Phys. Lett. 1993, 10 (7): 433-436 .  
Abstract   PDF(pc) (245KB) ( 479 )
We present distinct evidence of anticrossing behavior for excitonic transitions due to resonant coupling of heavy-hole ground levels in a biased GaAs/Al0.35 Ga0.65As/GaAs (50/40/100Å) asymmetric coupled-double-quantum-wells p-i-n structure by using photoluminescence spectra. The minimum level splitting is about 2.5meV.
Quantum-Mechanical Method for the Soliton Transported Bio-energy in Protein
PANG Xiaofeng
Chin. Phys. Lett. 1993, 10 (7): 437-440 .  
Abstract   PDF(pc) (202KB) ( 565 )
The equations of motion of the soliton transported bio-energy in the protein, were heretofore already obtained by a combination of quantum-mechanical and classical methods, but here have been derived based completely on quantum mechanics. And we point out the shortcoming of no self-consistency of the Davydov theory. Some interesting results have also been got.

A Study of Weak Laser-DNA Molecule Interaction and Its Chaotic Behaviour
ZHOU Lingyun
Chin. Phys. Lett. 1993, 10 (7): 441-444 .  
Abstract   PDF(pc) (160KB) ( 499 )
The motion equations with the effect of laser-deoxyribonucleic acid (DNA) molecule interaction are advanced. The chaotic behaviour about these equations were studied by Afelnikov’s method. It is found that DNA molecule system can turn into chaotic state under the weak laser action. This result is
helpful for the explanation of laser-induced biological genetic variation effect.
The Motion of a Gyroscope Freely Falling Along the Radial Geodesic in the Space-Time of a Black Hole with a Global Monopole
JING Jiliang, YU Hongwei, WANG Yongjiu
Chin. Phys. Lett. 1993, 10 (7): 445-448 .  
Abstract   PDF(pc) (153KB) ( 496 )
By means of the orthonormal frame, the motion of the axis of a gyroscope freely falling along the radial geodesic in the space-time of a black hole with a global monopole is investigated. It is shown that the axis of the gyroscope rotates about the radial direction as it falls into the black hole.

16 articles