期刊：
JOURNAL OF PHYSICS-CONDENSED MATTER,1997年9(23):4925-4930 ISSN：0953-8984
作者机构：
CENT CHINA NORMAL UNIV,DEPT PHYS,WUHAN 430070,HUBEI,PEOPLES R CHINA.;ACAD SINICA,INT CTR MAT PHYS,SHENYANG 110015,PEOPLES R CHINA.;NANJING UNIV SCI & TECHNOL,DEPT APPL PHYS,NANJING 210014,PEOPLES R CHINA.;UNIV SCI & TECHNOL CHINA,CTR FUNDAMENTAL PHYS,HEFEI 230026,ANHUI,PEOPLES R CHINA.;CENT CHINA NORMAL UNIV,DEPT PHYS,WUHAN,HUBEI,PEOPLES R CHINA.
摘要：
The magnetic properties of icosahedral MRu12 clusters are studied using the discrete-variational local-spin-density-functional method, where M = V, Cr, Mn, Fe, Co, and Ni. The results show that all of the I-h MRu12 clusters, just like the case for the I-h Ru-13 cluster, have double magnetic solutions. In contrast to the moment of 4 mu(B) for the I-h Ru-13 cluster, the total magnetic moments of the I-h MRu12 clusters, ranging from 1 mu(B) to 20 mu B, have been changed greatly by the substitution of the central Ru atom with M. Among them, the NiRu12 cluster has a giant moment of 20 mu(B). Furthermore, the NiRu12 cluster has nondegenerate ground state and could be expected to be remarkably stable. Therefore, for the purpose of enhancing the magnetic moment of the I-h Ru-13 cluster, Ni is a promising candidate as a dopant. Finally, we predict that all the I-h MRu12 clusters except NiRu12 might belong to the class in which the magnetization of the cluster increases with temperature.
摘要：
The variation with radius of the physical parameters(scale height, central temperature, and central density) of a self-gravitation and magnetized accretion disk is examined. We have adopted the different opacities in different regions as in the work by Collin-Souffrin and Dumont(1990II), and we consider a disc model with a 107M⊙ black hole at the center and with an accretion rate of 0.01M⊙/yr. Most of our results are very similar to theirs, but there are some differences between ours and theirs, that is: the critical radius where X-rays are able to heat significantly the disc is not sensitive to self-gravitation. However, self-gravitation has an influence on the location of the radius which emits the bulk of UV radiation, and the magnetic field affects both of them.
作者机构：
CCAST, WORLD LAB, BEIJING 100080, PEOPLES R CHINA.;HUAZHONG NORMAL UNIV, INST PARTICLE PHYS, WUHAN 430070, PEOPLES R CHINA.;[Jia, Y] Institute of Particle Physics, Huazhong Normal University, Wuhan 430070, China<&wdkj&>CCAST (World Laboratory), P. O. Box 8730, Beijing 100080, China<&wdkj&>Department of Physics, Huazhong Normal University, Wuhan 430070, China;[Li, JR] Institute of Particle Physics, Huazhong Normal University, Wuhan 430070, China;[Chen, YC] Department of Physics, Huazhong Normal University, Wuhan 430070, China
摘要：
We have investigated atomic coherent population trapping in a multilevel model of laser-induced continuum structure, in which a quasicontinuum of excited levels to be modeled as the Bixon-Jortner quasicontinuum is laser-embedded into a previously structureless atomic continuum. The condition leading to atomic coherent population trapping and the coherent population trapping state are given explicitly. The effects of nondegenerate detuning, the Fano factors and the laser intensities on the amount of population trapped in the atomic bound states and the populations distributed in the quasicontinuum are also examined.
作者机构：
[Li, JR; Hou, DF] HUA ZHONG NORMAL UNIV,INST PARTICLE PHYS,WUHAN 430070,PEOPLES R CHINA.
通讯机构：
Inst. für Theoretische Physik, Germany
摘要：
By considering the Debye screening and the damping rate of gluons, the viscosity coefficient of the quark-gluon plasma was evaluated via real-time finite temperature QCD in the relaxation time approximation at finite temperature and chemical potential. The results show that both the damping rate and the quark chemical potential cause considerable enhancements to the viscosity coefficient of the hot dense quark-gluon plasma. (C) 1997 Elsevier Science B.V.
期刊：
Chinese Astronomy and Astrophysics,1997年21(3):269-276 ISSN：0275-1062
通讯作者：
Wang, D.-X.
作者机构：
Department of Physics, Central-South Nationalities College, Wuhan 430074, China;Department of Physics, Ctrl. China Univ. of Sci. and T., Wuhan, China;[YangLan-tian] Institute of Astrophysics, Central China Normal University, Wuhan, China;[WangDing-xiong] Department of Physics, Central-South Nationalities College, Wuhan 430074, China, Department of Physics, Ctrl. China Univ. of Sci. and T., Wuhan, China
通讯机构：
[Wang, D.-X.] D;Department of Physics, Central-South Nationalities College, China
关键词：
Accretion disk;Instability
摘要：
We examine a weakly magnetized isothermal accretion model containing diffusing type viscosity for axisymmetric pulsational instability. It is shown that in general there exist four modes of axisymmetric oscillation, two of which are pulsationally unstable and the other two, stable, for which, respectively, the magnetic field and viscosity act as de-stabilizing and stabilizing factors. We also note that the magnetic field components affect mainly the instability of nearly axial pulsations and the viscosity, that of radial pulsations.
