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Volume 10 Issue 2
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Original Articles
Modified Carlsson-Gelatt-Ehrenreich Scheme for the Inverse Problem of Cohesive Energy
DENG Wenji, CHEN Nanxian, LIU Youyan, GONG Changde
Chin. Phys. Lett. 1993, 10 (2): 65-67 .  
Abstract   PDF(pc) (153KB) ( 431 )
By using the Hardy-Wright-Möbius inverse formula, we have improved the Carlsson-Gelatt-Ehrenreich scheme for the inverse problem of cohesive energy. The advantage of the new method is that the inverse formula are in a sense independent of the geometries of lattices.
On the Invalidity of a Conjecture of Dirac
LI Ziping
Chin. Phys. Lett. 1993, 10 (2): 68-70 .  
Abstract   PDF(pc) (169KB) ( 598 )
Besed on the symmetry properties of constrained Hamiltonian system, we present one other example to show that Dirac’s conjecture fails in a different way than other examples in that there is no linearization of constraint in this problem. A clear discussion is made on the relationships of the coefficients connecting with the first-class constraints in the gauge generator for a constrained Hamiltonian system. The results of this counterexample are also in contradiction with the other conclusions.
Retardation Effect on Baryon Spectra
DONG Yubing, SU Junchen, WU Shishu
Chin. Phys. Lett. 1993, 10 (2): 71-74 .  
Abstract   PDF(pc) (189KB) ( 320 )
The retardation effect of gluon propagation on baryon spectra is examined. The calculated results show that the consideration of this effect gives appreciable improvements on both positive and negative parity baryon spectra.
Heat Kernel Expansion at Finite Temperature in Curved Space
XU Dianyan, XU Xiaofeng*
Chin. Phys. Lett. 1993, 10 (2): 75-78 .  
Abstract   PDF(pc) (138KB) ( 417 )
The method of heat kernel expansion at finite temperature in curved space is proposed in this letter. The general formulas are derived which are covariant under the general coordinate transformations. The thermal De Witt-Seeley-Gilkey coefficients E2(x, β) and E4(x, β) are calculated.
NNπ Interaction at Finite Temperature and Finite Density
HU Sizhu, ZHENG Guotong, CAI Shengshan, SU Rukeng
Chin. Phys. Lett. 1993, 10 (2): 79-82 .  
Abstract   PDF(pc) (0KB) ( 382 )
By means of the Matsubara imaginary-time Green's function method, we extend the NNπ interaction to finite-temperature and finite-density by summing bubble diagrams. We find that the effective mass of pion increases but the effective NNπ interaction decreases as the density and/or temperature increase.
A Study of the Upper Limit of vτ-Mass at BEPC
DU Dongsheng, GU Jianhui, HUANG Tao, JIN Shan, LI Jin, LIU Chun
Chin. Phys. Lett. 1993, 10 (2): 83-85 .  
Abstract   PDF(pc) (143KB) ( 424 )
By using the new result of τ-mass from Beijing spectrometer and the data of τ→5πvτ from ARGUS, the upper limit of vτ-mass of 30 MeV is obtained at 95% confidence level. The upper limit of the vτ-mass could be largely reduced if a high resolution detector is used in the improved Beijing electron positron collider, which is under discussion.
Calculation of the Matrix Elements of 12C for the 15.1MeV Level
Pao Lu, B. P. Nigam, Yueh Shan
Chin. Phys. Lett. 1993, 10 (2): 86-88 .  
Abstract   PDF(pc) (122KB) ( 462 )
We present here the result of the calculation on the ratio of
|<1+||Tmag1||0+>1/q|2/|<1+||Tmag1||0+>1/q|2q=0 for the 15.1 MeV level in 12C. We use the wave function corresponding to the nucleons moving in a common harmonic potential plus a hard core.

On Fusion Reactions Induced by 11Li via Soft Dipole Mode and Static Deformation
LIU Guiming, FU Deji*, CHENG Xiaowu
Chin. Phys. Lett. 1993, 10 (2): 89-92 .  
Abstract   PDF(pc) (184KB) ( 394 )
The numerical calculations for fusion reactions of a halo nucleus 11Li with deformed target nuclei at low energies have been carried out under the sudden limit for rotational excitation combined with a double folding potential of ion-ion interaction. The properties of fusion cross section involving the combined effects both from projectiles and target nuclei in such systems are investigated in detail.
An Improved Microscopic Method for Calculating Initial Exciton Number
MA Yugang, SHEN Wenqing, FENG Jun
Chin. Phys. Lett. 1993, 10 (2): 93-96 .  
Abstract   PDF(pc) (237KB) ( 405 )
An improved microscopic model to calculate the initial exciton number has been developed on the basis of original microscopic model-so-called phase-space model. In our model the particle number p0 and hole number h0 are treated separately and the Vlasov or BUU dynamics is used during the nucleus-nucleus collision instead of simple dynamical process without friction. This model reproduces the experimental results rather well.
The α Transfer Effect on Sub-barrier Fusion of Heavy Ions
SHEN Hong, HE Guozhu
Chin. Phys. Lett. 1993, 10 (2): 97-99 .  
Abstract   PDF(pc) (134KB) ( 505 )
The α transfer effect on sub-barrier fusion is calculated for 16O+148Sm system by using the linear combination of nuclear orbits theory. The coupling between elastic scattering channel and α transfer reaction channel causes the enhancement of the fusion cross section at sub-barrier energies.
Probe Contamination Effect in Silane Plasma and its Improvement
XI Zhonghe, ZHANG Guanghua, YANG Fan, XU Fang, ZHANG Qiang*
Chin. Phys. Lett. 1993, 10 (2): 100-102 .  
Abstract   PDF(pc) (180KB) ( 510 )
The contamination behavior of Langmuir probe in silane glow discharge plasma are discussed. A hot electrical probe is suggested to improve the diagnostics of SiH4 plasma. Results show the safe duration for reliable measurements of electron temperature can be as long as 40min by this method.
Molecular Dynamics Simulations on the Consolidation Process and Relaxed Structure of Nanocrystalline Alpha-Iron
CHEN Zhiying, YUAN Quan, DING Jiaqiang
Chin. Phys. Lett. 1993, 10 (2): 103-106 .  
Abstract   PDF(pc) (221KB) ( 465 )
The consolidation process of nanocrystalline α-Fe from single crystal grains is simulated and its relaxed atomic structure is obtained using molecular dynamics method. A uniaxial tensile “computer experiment ”on this model nanocrystalline material proves that this “material ”is mechanically stable and may be useful for the further studies on its mechanical and physical properties. As prepared nanocrystalline α-Fe consists of a crystalline component and a grain boundary component. This result agrees with experimental facts qualitatively. The calculated radial distribution function shows that the structure of the grain boundary component of nanocrystalline α-Fe appears to have an atomic distribution of short-range order.
Physical Model of the Anomalously Amplitude Dependent Internal Friction Peak (PlPeak)
FANG Qianfeng
Chin. Phys. Lett. 1993, 10 (2): 107-110 .  
Abstract   PDF(pc) (173KB) ( 399 )
A model of the interaction between the solute atoms and the dislocations bowing out under the action of the internal stress is proposed to interpret the P1 peak. On the basis of this model ahd the comparison between theoretical and experimental results the important relaxation parameters of P1peak such as relaxation time and relaxation energy are obtained approximately.
Tunneling Between High-Tc Oxide and Normal Metal
XIAO Mingwen, LI Zhengzhong, QIU Yang
Chin. Phys. Lett. 1993, 10 (2): 111-114 .  
Abstract   PDF(pc) (258KB) ( 490 )
In slave-fermion representation t - J model is adopted to study the tunneling between high-Tc oxide and normal metal. The differential conductance shows an asymmetric V-shape behavior on a constant background. The constant results from the motions of holons on the background of the spiral antiferromagnetism produced by partially condensed spinons. The asymmetry changes with hole concentration and becomes insignificant in the region optimal for high-Tc superconductivity.
Nonlinear Optical Absorption in Polydiacetylene Crystal
PENG Jingcui
Chin. Phys. Lett. 1993, 10 (2): 115-118 .  
Abstract   PDF(pc) (176KB) ( 473 )
In this paper, the nonlinear optical absorption under two input optical waves is investigated. The nonlinear absorption coefficient is derived, and numerical results are calculated, which agree with experimental results.
Development of Valence Bands of C60 from Submonolayer to Two and Three Dimensionality
XUN Kun, DENG Junzhuo, LIU Fengqin, YAO Jun, LÜ, Sihua, WANG Zuquan, WU Sicheng,
Chin. Phys. Lett. 1993, 10 (2): 119-122 .  
Abstract   PDF(pc) (257KB) ( 456 )
For submonolayer amounts of C60 condensed on Sn substrate, the peaks derived from top two occupied molecular orbitals were broadened by 0.3eV in comparison with solid C60. For coverage θ < 1 monolayer, the broadenings are independent of the coverage. It indicates that the delocalizations of electrons in valence bands of C60 are weak and the widths do not reflect the true band dispersions.
UV Laser Induced Reaction Between C60 and W(CO)6 in Benzene Solution
ZHANG Jie, WANG Wenhua, ZHANG Tingjiang*, ZHENG Minghui* LIN Jingu, SHE Yongbo, FU Kejian
Chin. Phys. Lett. 1993, 10 (2): 123-125 .  
Abstract   PDF(pc) (163KB) ( 520 )
UV laser induced reaction between C60 and W(CO)6 in benzene solution was studied by infrared absorption spectroscopy. The reversible formation of a C60 complex of w(CO)5, presumably (η2- C60)W(CO)5, was observed.
Thermal Radiation of Dirac Particles from Vaidya Black Hole
LI Zhongheng*, ZHAO Zheng
Chin. Phys. Lett. 1993, 10 (2): 126-128 .  
Abstract   PDF(pc) (95KB) ( 508 )
With a new method calculating the location and temperature of the event horizon of the non-static black hole, the Dirac equation is reduced and solved near the horizon in Vaidya space-time when the tortoise coordinate is adopted. The location of Vaidya event horizon, the Hawking temperature and the formula of thermal spectrum of the Dirac particles are derived.
18 articles