Chin. Phys. B
Citation Search Quick Search

ISSN 1674-1056 (Print)
CN 11-5639/O4
About
   » About CPB
   » Editorial Board
   » SCI IF
   » Staff
   » Contact
Browse CPB
   » In Press
   » Current Issue
   » Earlier Issues
   » View by Fields
   » Top Downloaded
   » Sci Top Cited
Authors
   » Submit an Article
   » Manuscript Tracking
   » Call for Papers
   » Scope
   » Instruction for Authors
   » Copyright Agreement
   » Templates
   » Author FAQs
   » PACS
Referees
   » Review Policy
   » Referee Login
   » Referee FAQs
   » Editor in Chief Login
   » Editor Login
   » Office Login
Links
   »
HighLights More»   
Chin. Phys. B  
  Chin. Phys. B--2000, Vol.9, No.7
Select | Export to EndNote
GENERAL

TIME-DEPENDENT LANDAU SYSTEM AND NON-ADIABATIC BERRY PHASE IN TWO DIMENSIONS

Jing Hui, Wu Jian-sheng
Chin. Phys., 2000, 9 (7): 481-484 doi: 10.1088/1009-1963/9/7/001
Full Text: [PDF 178 KB] (Downloads:366)
Show Abstract
By applying the time-independent unitary transformation, the time-dependent Landau system is transformed into a product of a time-independent Landau system's Hamiltonian and a factor only depending on time, which can be solved exactly. Both the invariant operator and the eigenstate are obtained. In the periodical time-dependent case, the non-adiabatic Berry's phase is also presented.

THE GROWTH RATE AND STATISTICAL FLUCTUATION OF BOSE-EINSTEIN CONDENSATE FORMATION

Yan Ke-zhu, Tan Wei-han
Chin. Phys., 2000, 9 (7): 485-489 doi: 10.1088/1009-1963/9/7/002
Full Text: [PDF 116 KB] (Downloads:396)
Show Abstract
Using the generating function method to solve the master equation of Bose-Einstein condensate and to evaluate the growth rate, statistical fluctuation of condensate atoms, we find out that there is a plateau in the growth rate curve and a super-Poisson distribution observed.
NUCLEAR PHYSICS

STUDY OF THE NUCLEAR PHENOMENA IN THE LOW ENERGY (60-360 keV) PROTON BEAM IMPLANTATION ON METALS

Wang Tie-shan, Zhu Yong-tai, Wang Zhi-guo, Li Song-lin, Wang Shu-jin, Jin Gen-ming
Chin. Phys., 2000, 9 (7): 494-499 doi: 10.1088/1009-1963/9/7/004
Full Text: [PDF 1892 KB] (Downloads:394)
Show Abstract
A series of studies on the nuclear interaction and its effects in solids during proton implantation were performed in the energy region between 60 and 360keV. Some charged particle products were observed in the implantation experiments on metal samples such as deuterated titanium, titanium alloy, titanium foil on molybdenum substrate, molybdenum and stainless steel, etc.. The energies of the charged particle products are about 3.9, 5.6 and 8.4MeV, respectively. These particles were identified as alpha particles with both detector telescope and absorption measurements. These three kinds of alpha products were found from different proton sub-barrier reactions. The exciting curve of this reaction increases exponentially with the growth of proton energy in the energy region from 90 to 330keV. The radiation damages induced by the nuclear products in the sample have been studied with scanning electron microscopy technique. The possible surface damages induced by them were observed evidently. The origin of the nuclear reactions and their effect on implantation are discussed.
CLASSICAL AREAS OF PHENOMENOLOGY

ON THE BREAKDOWN OF A LONG STREAK IN A TRANSITIONAL BOUNDARY LAYER

Lee Cun-biao, Fu Song
Chin. Phys., 2000, 9 (7): 508-514 doi: 10.1088/1009-1963/9/7/007
Full Text: [PDF 5207 KB] (Downloads:413)
Show Abstract
Transition in regular K-regime of boundary layer is studied. The features of the long streak that is considered as a form of soliton/like coherent structure (CS-soliton) are investigated briefly. The experiment shows that the breakdown of long streak is generated by chain of ring-like vortices.

LATTICE BOLTZMANN METHOD SIMULATION ON THE FLOW OF TWO IMMISCIBLE FLUIDS IN COMPLEX GEOMETRY

Fang Hai-ping, Wan Rong-zheng, Fan Le-wen
Chin. Phys., 2000, 9 (7): 515-518 doi: 10.1088/1009-1963/9/7/008
Full Text: [PDF 124 KB] (Downloads:387)
Show Abstract
The multicomponent nonideal gas lattice Boltzmann model by Shan and Chen (S-C) can be used to simulate the immiscible fluid flow. In this paper, we show that the relaxation constant τ≤1 is a necessary condition for the immiscible fluid flow in the S-C model. In a system with very complex boundary geometry, for 0.8≤τ≤1, the S-C model describes the immiscible flow quite well, and τ=1 is the best.
ATOMIC AND MOLECULAR PHYSICS

STUDY OF BRANCHING RATIONS OF 3p3/2nd (J=1,3) AUTOIONIZING SERIES OF NEUTRAL MAGNESIUM

Li Cong-qi, Dai Chang-jian, Lü Jun
Chin. Phys., 2000, 9 (7): 500-503 doi: 10.1088/1009-1963/9/7/005
Full Text: [PDF 136 KB] (Downloads:418)
Show Abstract
With the K matrix and multichannel quantum defect theory, we have studied the branching ratios of 3p3/2nd (J=1,3) autoionizing series of Mg above the 3p1/2 ion limit. The calculations are compared with the previous experimental spectra, and the unmeasured branching ratios are presented. The conclusion is that 3p3/2nd state prepared by the three-step excitation can form population inversion between the 3p1/2 and 3s1/2 ionic states.

MODEL STRETCHING ENERGY LEVELS FOR SF6 MOLECULE

Zhu Jun, Cheng Yan, Chen Xiang-rong, Gou Qing-quan
Chin. Phys., 2000, 9 (7): 504-507 doi: 10.1088/1009-1963/9/7/006
Full Text: [PDF 98 KB] (Downloads:377)
Show Abstract
A four-parameter nonlinear model is introduced to the description of the X-Y stretching modes of XY6 octahedral molecules in the electronic ground state. We here only apply it to the calculations of S-F stretches of SF6 molecule. The model calculations appear to describe the observed data well, and predict some new vibrational bands at accurate energies not yet observed.
THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

THE NONLINEAR QCD DYNAMICAL EQUATIONS WITH HIGHER ORDER EFFECTIVE COUPLING

He Bo, Zhu Wu-ming
Chin. Phys., 2000, 9 (7): 490-493 doi: 10.1088/1009-1963/9/7/003
Full Text: [PDF 94 KB] (Downloads:297)
Show Abstract
Through studying the nonlinear QCD dynamical equations with higher order effective coupling, we find that shadowing effect is substantially weaker than that neglecting higher order effective coupling. This conclusion is very important for explaining the data from DESY ep collider HERA.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

EFFECT OF EXCITATION-AUTOIONIZATION IN NON-LOCAL THERMODYNAMIC EQUILIBRIUM PLASMAS

Wu Ze-qing, Zhang Ben-ai, Qiu Yu-bo
Chin. Phys., 2000, 9 (7): 519-522 doi: 10.1088/1009-1963/9/7/009
Full Text: [PDF 115 KB] (Downloads:449)
Show Abstract
Based on the detailed configuration accounting model, the authros have developed a method to calculate the rate of excitation-autoionization (EA) in the average atom model and used it in the rate equations. The numerical results show that EA effect is signifficant in high temperature low density plasma and can cause an additional ionization up to 15% of an ionization stage.

CRITICAL MAGNETIC SHEAR FOR THE TOKAMAK IDEAL INTERNAL KINK MODE IN THE ION KINETIC REGIME

Shi Bing-ren, Long Yong-xing, Sui Guo-fang, Li Ji-quan
Chin. Phys., 2000, 9 (7): 523-527 doi: 10.1088/1009-1963/9/7/010
Full Text: [PDF 147 KB] (Downloads:354)
Show Abstract
It is shown that for the ideal internal kink mode of tokamak plasma, there exists a critical magnetic shear s0c for its excitation when the finite ion Larmor radius effect is considered in the mode singular layer. This can be related to the sudden onset of the sawtooth and also to the stabilization of the sawtooth by the trapped hot ions observed experimentally. The alpha particle effect on this mode is revisited and some new results are reported.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

MICROSTRUCTURE AT THE INTERFACE OF TITANIUM CARBIDE AND NICKEL ALUMINIDES

Shen Dian-hong, Wu Xing-fang, Lu Hua, N. Froumin, M. Polak
Chin. Phys., 2000, 9 (7): 528-531 doi: 10.1088/1009-1963/9/7/011
Full Text: [PDF 3483 KB] (Downloads:476)
Show Abstract
Microstructure at the interface of titanium carbide and nickel aluminides in the samples obtained by infiltration of molten Ni3Al alloy has studied by a scanning electron microscopy (SEM) and an analytical transmission electron microscopy (ATEM) with an energy dispersive spectrometer (EDS). It is found that the morphology at the interfaces between hard phase skeleton of TiC0.7 and metallic phases depends on the ratio of Ti/C in carbide. Some periodic zigzag fringes are observed at a smooth interface between metallic phase and carbides in the sample of Ni3Al/TiC0.7. The results of analysis using EDS show that Ti in TiC0.7 carbide is easier than that in TiC0.7 to dissolve into the molten alloy during solid-liquid reaction. The formation of this periodic zigzag fringe,which may be a growth zone of a new Ti-Ni-Al phase,in the interface of TiC0.7/Ni3Al would occur during the initial stage of solidification.

RAPID DENDRITIC GROWTH INVESTIGATED WITH ARTIFICIAL NEURAL NETWORK METHOD

Wang Nan, Zhang Jun, Wei Bing-bo, Dai Guan-zhong
Chin. Phys., 2000, 9 (7): 532-536 doi: 10.1088/1009-1963/9/7/012
Full Text: [PDF 147 KB] (Downloads:405)
Show Abstract
Rapid dendritic growth of γ-(Ni, Fe) phase, β-CoSb intermetallic compound and α-Fe phase was realized by undercooling Ni-10%Fe single phase alloy, Co-60.5%Sb intermetallic alloy and Fe-40%Sn hypomonotectic alloy to a substantial extent. Their experimentally measured dendrite growth velocities were 79.5m/s, 12m/s and 0.705m/s, corresponding to undercooling levels of 303K(0.18TL), 168K(0.11 TL) and 219K(0.15 TL) respectively. Since the usual dendrite growth theory deviates significantly from reality at great undercoolings, an artificial neural network incorporated with stochastic fuzzy control was developed to explore rapid dendrite growth kinetics. It leads to the reasonable prediction that dendritic growth always exhibits a maximum velocity at a certain undercooling, beyond which dendrite growth slows down as undercooling increases still further. In the case of Fe-Sn monotectic alloys, α-Fe dendrite growth velocity was found to depend mainly on undercooling rather than alloy composition.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

FABRICATION AND CHARACTERIZATION OF THE SIZE-CONTROLLED AND PATTERNED nc-Si DOTS

Li Jian, Wang Li, Huang Xin-fan, Jiang Ming, Li Wei, Wang Zhao-ye, Xu Jun, Liu Zhi-guo, Chen Kun-ji
Chin. Phys., 2000, 9 (7): 537-540 doi: 10.1088/1009-1963/9/7/013
Full Text: [PDF 1488 KB] (Downloads:504)
Show Abstract
A new method of phase-modulated excimer laser crystallization is adopted to fabricate the patterned nanometer-sized crystalline silicon (nc-Si) dots within the sandwiched structure (a-SiNx:H/a-Si:H/a-SiNx:H) films. The results of transmission electron microscopy, electron diffraction and Raman scattering show the ultra-thin and single-layer nc-Si films were patterned in the lateral direction and the size of crystallites is controlled by the thickness of as-deposited a-Si film in the longitudinal direction. The effects of the laser energy density on the structures of the samples and the crystallization mechanism are discussed.

MAGNETIC VISCOSITY OF NANOCOMPOSITE Sm-Fe-Cu-Zr-Ga-C RIBBONS

Zhang Shao-ying, Zhang Hong-wei, Zhao Peng, Shen Bao-gen, F. R. de Boer, K. H. J. Buschow
Chin. Phys., 2000, 9 (7): 541-544 doi: 10.1088/1009-1963/9/7/014
Full Text: [PDF 136 KB] (Downloads:401)
Show Abstract
The magnetic viscosity was investigated at temperatures between 100 and 293 K for the nanocomposite Sm2Fe18.25Zr0.25Cu0.5Ga2C2 ribbons prepared by melt-spinning and subsequent annealing. It was found that the maximum S and χirr, located near coercivity, increase with increasing temperature. The viscosity parameter Sv was found to be strongly dependent on the applied fields at lower fields than the coercivities. The relation between Sv and coercivity was analyzed. The coercivity mechanism is mainly controlled by domain-wall pinning. The activation volume associated with magnetization reversal, which can be calculated from Sv, is much smaller than the grain volume.

GREAT MAGNETIC ENTROPY CHANGE IN La(Fe, M)13 (M=Si, Al) WITH Co DOPING

Hu Feng-xia, Shen Bao-gen, Sun Ji-rong, Zhang Xi-xiang
Chin. Phys. B, 2000, 9 (7): 550-553 doi: 10.1088/1009-1963/9/7/016
Full Text: [PDF 172 KB] (Downloads:827)
Show Abstract
Very large magnetic entropy change Δ SM, which originates from a fully reversible second-order transition at Curie temperature TC, has been discovered in compounds La(Fe, Si)13, La(Fe, Al)13 and those with Co doping. The maximum change ΔSM\approx19 J·kg-1·K-1, achieved in LaFe11.4Si1.6 at 209K upon a 5T magnetic field change, exceeds that of Gd by more than a factor of 2. The TC of the Co-doped compounds shifts to higher temperatures. ΔSM still has a considerable large magnitude near room temperature. The phenomena of very large ΔSM, convenience of adjustment of TC, and also thesuperiority of low cost, strongly suggest that the compounds La(Fe, M)13 (M=Si, Al) with Co doping are suitable candidates for magnetic refrigerants at high temperatures.
Copyright © the Chinese Physical Society
Address: Institute of Physics, Chinese Academy of Sciences, P. O. Box 603,Beijing 100190 China(100190)
Tel: 010-82649026   Fax: 010-82649027   E-Mail: cpb@aphy.iphy.ac.cn
Supported by Beijing Magtech Co. Ltd. Tel: 86-010-62662699 E-mail: support@magtech.com.cn