1992 Vol. 16, No. 5

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Mossbauer Study of GdBa2Cu3O7-δ
CHEN Zhi-Qian, ZHENG Ren-Rong, YIN Chuan-Zong
1992, 16(5): 385-389.
57Fe-Mossbauer spectra of GdBa2 (Cu1-xFex)O7-δ (x=0.005) are studied at a wide temperature range (1.4K-700K),and the valence states and surroundings of iron cations are analyzed.There are four sites for Fe:A,B,C and D.Fe(A),Fe(B) and Fe(C) occupy Cu (1) sites with different O-coordinations.Fe(D) is attributed to a Cu(2) site with only one defined O-surrounding.The Fe cations are identified as high spin 4+ at site B and 3+ at site D.Alignment of powder absorber in a magnetic field leads to small texture effects.
Variation of Intensity of High Energy Cosmic Ray Hadrons with Altitude
LU Sui-Ling, REN Jing-Ru, SU Shi, WANG Cheng-Rui, HE Mao
1992, 16(5): 390-391.
Using small Pb emulsion chambers placed at a camping site for Mr.Qomolangma mountaineering with an altitude of 6500m a.s.l.,the intensity of high energy cosmic ray hadrons is determined.Combining the data with those observed at Mt.Kanbala (5500m a.s.l.)and the Yunnan Cosmic Ray Observatory (3200m a.s.l.),the variation of high energy cosmic ray hadrons are obtained.
Propagation of Cosmic-Ray Nuclei with Reacceleration
ZHANG Li, ZHANG Ming, MU Jun, YU Chuan-Zan
1992, 16(5): 392-397.
Introducing effective energy change tate of galactic cosmic ray (GCR) during interstellar propagation,we obtain a general method of solving the propagation equation of GCR nuclei-modified slab weighted method.In the leaky box model,we give comparisons of calculated ratios of secondary and primary nuclei and primary energy spectra with observed results.
CP-Violating Effects in Two-Body Baryonic Decays of B0-B0 System
DU Dong-Sheng, XING Zhi-Zhong
1992, 16(5): 398-407.
CP-violating effects in partial-decay-decay-rate asymmetries for two-body baryonic decays of B0-B0 and B0-B0 systems are examined.We concentrate on those final states into which both B0 and B0 can decay.Two cases are discussed in detail:one is for Z0 factory for incoherent BB production,the other is for C=+1 BB production above the Υ(4S) resonance at symmetric colliders.The bb pairs needed for testing these effects are estimated for 3σ signature.For the decay modes B0→PP,Δ++Δ-- and Δ0Δ0,Nbb~107—108.
Description of the Complete Integrability of the SU(2) and SU(3) Self-Dual Yang-Mills Source-Free Field Equations System and Further Discussions
LI Fu-Bin
1992, 16(5): 408-413.
With the theory of harmonic maps and the eight-dimensional Riemannian manifold,the completely integrable SU(2) and SU(3) self-dual Yang-Mills source-free field equations are described.Sixteen independent Killing vector fields are determined,two transformation groups which map solutions into solutions are constructed,and a conjecture on the complete integrability of systems by the inverse scattering method is formulated.
The Crossing Matrices and Correlation Function in Nonunitary SUK(2) Wess-Zumino-Witten Model
HOU Bo-Yu, SHI Kang-Jie, YUE Rui-Hong
1992, 16(5): 414-422.
By using the Feigin-Fuch integral,we calculate the correlation function,operator product coefficient and crossing matrices in the nonunitary SUK(2) WZW model.We explicitly give the modular matrix and discuss the relations between the nonunitary SUK(2) WZW model and the unitary one.
s′ Boson and the S-D Truncation in the IBM
SANG Jian-Ping
1992, 16(5): 423-430.
In order to investigate the S-D truncation in the interacting boson model,s′-boson is considered to enlarge the collective subspace.The structures of the s,d and s′-bosons are determined in terms of one of the microscopic IBM approaches.The calculation and discussion of the s′-boson and the system including one s′-boson show that ,although the s′-boson has little contribution to the excited states below 2MeV which are already well described by the sd IBM,it is expected that the introducing of the s′-boson may extend the applicability of the model to a number of states above 2MeV.
State Densities of Deformed Nuclei Based on Axisymmetric Harmonic Oscillator Potential
YANG Xian-Jun, FAN Xi-Pei
1992, 16(5): 431-438.
On the premise of considering Pauli exclusion principle strictly,we have obtained an exact general formula of multiparticle and multi-hole state densities for any single-particle Hamiltonian.Besides,under the semi-classical Thomas-Fermi approximation,for deformed nuclei.we have derived a completely analytic expression of state densities based on axisymmetric harmonic oscillator potential.By means of this expression,we have calculated the state densities of g1p1h,g1p2h,g2p1h,g2p2h and their corresponding cumulative state densities of N1p1h,N1p2h,N2p1h,N2p2h,and made comparisons with the results based on the three-dimensional linear harmonic oscillator potential.The results indicate that for medium-heavy nuclei,deformation parameter has a great effect on state densities.
Final State Distribution and Signal of Quark-Gluon Plasma in High Energy Heavy-Ion Collisions
CHENG Qing-Hua, ZHUANG Peng-Fei, LIU Lian-Shou
1992, 16(5): 439-445.
With hydrodynamical model and equations of state,the dependence of the final state distributions on phase transition and its order is analysed in heavy-ion collisions.Because of the important collective phenomena at high energies and heavy nuclear mass,the rapidity distributions of 197Au-197Au collisions at 100+100GeV per pair of nucleons may be considered as the signal of quark-gluon plasma.
Measurement of the Complete Fusion Excitation Function for the 16O+24Mg Reaction
LIU Guo-Xing, ZHENG Ji-Wen, CHEN Ke-Liang
1992, 16(5): 446-452.
The complete fusion excitation function for the 16O+24Mg reaction has been measured in range of 41.6—50.0MeV in step of 0.30MeV with in-beam γ-spectroscopy technique.It is shown that the complete fusion excitation function for this system is not smooth and exist some fluctuations.The peak values of fluctuations correspond to 27.6 and 28.9MeV of center of mass energies.
Measurement of the Complete Fusion Excitation Function for the 16O+12C Reaction
WANG Su-Fang, ZHENG Ji-Wen, LIU Guo-Xing, CHEN Ke-Liang, BAI Xing-Ping, YU Xian, ZHENG Ping-Zi, ZHANG Huan-Qiao, XU Jin-Cheng, LIU Zu-Hua, XU Kan, RUAN Ming, LV Jun
1992, 16(5): 453-460.
The complete fusion excitation function has been measured for the 16O+12C reaction in the energy range of 50—90MeV with a position sensitive ΔE-E telescope system.It is found that the complete fusion excitation function is not smooth and exhibits some structures.The peak position of the fluctuations correspond to 26.0,31.0 and 36.4MeV in the center of mass system.The experimental results are discussed and compared with that obtained in previous works.
The Generalized q-Coherent State Representation of the Quantum Algebra SUq(2)
YU Zu-Rong
1992, 16(5): 461-467.
The generalized q-coherent state of the quantum group SUq(2) is defined.The q-coherent state realization of the quantum algebra SUq(2) is given.This realization may be considered as q-Dyson realization.In analogy to the usual Lie algebra SUq(2),the q-Holstein-Primakoff representation is also found from the q-Dyson representation.The transformation matrix between the q-Dyson and Holstein-Primakoff representation is obtained.
Entropy Production,Collision Number and the Forming Process of Hot Nucleus
LIU Jian-Ye, YANG Fu-Zhong
1992, 16(5): 468-474.
The time processes of entropy production and collision number in intermediate energy heavy ion collisions were calculated by use of BUU equation with momentum dependence mean field and nucleon-nucleon collisions in the medium.The effects of momentum dependence mean field and nucleon-nucleon collisions in the medium on the entropy production and collision number are obvious and sensitive to impact parameter and bombarding energy.Especially these time processes reflect the properties of hot nuclear matter.
Analytical Calculation of the Vibrator-Rotor Transition in the Sdg Interacting Boson Model
WANG Bao-Lin
1992, 16(5): 475-480.
Analytical calculation of the vibrator-rotor transition is given by utilizing the 1/N expansion technique in the sdg IBM.The phase transition of low-lying energy spectrum and E2 transition for Sm isotopes are calculated.