Table of Content

20 July 1996, Volume 5 Issue 7 Previous Issue    Next Issue

THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Select

THE TWO-BOSON SCATTERING PHASE SHIFTS IN THE GENERAL φ6 THEORY WITH THE GAUSSIAN WAVE-FUNCTIONAL APPROACH LU WEN-FA, XU BO-WEI, ZHANG YU-MEI 1996, 5 (7):  481-492.  doi: 10.1088/1004-423X/5/7/001 Abstract ( 0 )   PDF (272KB) ([an error occurred while processing this directive])   The two-particle scattering phase shifts with a λφ4 +ξφ6 interaction are com-puted in (1 + 1) and (2 + 1) dimensions using the Gaussian wave-functional approach.Through numerical analysis, we give the phase-shift curves with respect to the scat-tering energy for most cases of this theory. In (1 + 1) and (2 + 1 ) dimensions, for the symmetry vacuum the phase shifts are positive or negative depending on the signs of the renormalized parameter, while for the asymmetric vacuum the phase shifts are negative.

ATOMIC AND MOLECULAR PHYSICS

Select

A NEW EXPERIMENTAL METHOD IN THE STUDY OF IONIC RYDBERG STATES BY RESONANCE IONIZATION MASS SPECTROSCOPY HUANG WEN, XU XIANG-YUAN 1996, 5 (7):  493-498.  doi: 10.1088/1004-423X/5/7/002 Abstract ( 0 )   PDF (169KB) ([an error occurred while processing this directive])   We report a new method for detecting highly excited ions. With a strong constant electric field ionization following the extracting of ions by a pulsed electric field in a time-of-flight mass spectrometer, the direct multi-photon ionization background can be eliminated in laser multi-step resonance ionization mass spectroscopy of ionic Rydberg states. A high detection efficiency call be obtained for law members of ionic Rydberg states by use of this method. We have applied the method in the study of the spectroscopy of ionic Rydberg states ia ytterbium.

Select

K-SHELL IONIZATION OF IRON BY ELECTRON BOMBARDMENT HE FU-QING, LONG XIAN-GUAN, PENG XIU-FENG, LUO ZHENG-MING, AN ZHU 1996, 5 (7):  499-504.  doi: 10.1088/1004-423X/5/7/003 Abstract ( 0 )   PDF (156KB) ([an error occurred while processing this directive])   K-shell ionization cross sections for Fe by electron impact were measured by detecting the characteristic X-rays emitted from the thin solid film target of known mass thickness with a Si(Li) detector. Reflection correction of the substrate was done using a bipartition model of electron transport. The experimental results are satisfactory as compared with the theoretical calculation and empirical formula.

CLASSICAL AREAS OF PHENOMENOLOGY

Select

INFLUENCE OF DRIVING-FIELD PHASE FLUCTUATION ON ABSORPTION AND DISPERSION IN A SIMPLE THREE-LEVEL ATOMIC SYSTEM GONG SHANG-QING, XU ZHI-ZHAN, TENG HUA-GUO 1996, 5 (7):  505-510.  doi: 10.1088/1004-423X/5/7/004 Abstract ( 0 )   PDF (164KB) ([an error occurred while processing this directive])   The steady-state behavior of a simple three-level atomic system has been investi-gated by taking into account the effect of phase fluctuations in the driving field. For a monochromatic driving field, lasing with or without inversion can be established over a wide frequency range for the probe and driving fields. A large refractive index can also be generated even if the population inversion is positive. For a finite linewidth of the driving field, the refractive index enhancement tends to decrease. Furthermore, a behavior change from inversion laser to noninversion laser can occur as the driving field linewidth increases.

Select

THEORETICAL STUDIES ON LASER-INDUCED GRATINGS IN ORGANIC PHOTOISOMERS SI JIN-HAI, ZHAO JIANG, WANG YOU-GUI, YE PEI-XIAN 1996, 5 (7):  511-519.  doi: 10.1088/1004-423X/5/7/005 Abstract ( 0 )   PDF (301KB) ([an error occurred while processing this directive])   A theoretical model for formation of light-induced gratings in organic photoisomers is presented. Using this model, dynamic behaviors of the light-induced gratings are studied theoretically for two different cases: in the first case, in addition to a CW loser generating the writing beams and the reading beam, a pulsed laser is used as an optical pump, in the second case, the writing beams are provided by a pulsed laser, and the reading beam comes from a CW laser. Agreement between experiment and theory is also demonstrated.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

Select

THEORETICAL INVESTIGATION OF ELECTRON-NEUTRAL ATOM COLLISION PROCESS AND ELECTRON TRANSPORT PARAMETERS IN DC GLOW DISCHARGE OF PLASMA WITH A TRANSVERSE MAGNETIC FIELD WEI HE-LIN, LIU ZU-LI, LI ZAI-GUANG, ZHENG QI-GUANG 1996, 5 (7):  520-529.  doi: 10.1088/1004-423X/5/7/006 Abstract ( 0 )   PDF (264KB) ([an error occurred while processing this directive])   A Monte Carlo simulation (MCS) technique is used to simulate the cathode sheath region of a helium dc glow discharge. In such a simulation, a nonuniform electric field and a transverse uniform magnetic field are considered. When the magnetic field intensity increases from 0 to 800 G, all types of collision considered in this paper are enhanced. This result is in agreement with the experimental result. The results also show that with the increase of magnetic field intensity, the electron transport time, the electron density increase, and the electron mean energy decreases.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

Select

MICROSTRUCTURE AND FRACTAL FORMATION OF ANNEALED Ge-Au FILM AND Ge-Au/Au BILAYER FILMS BA LONG, ZENG JIAN-LIN, ZHANG SHU-YUAN, WU ZI-QIN 1996, 5 (7):  530-537.  doi: 10.1088/1004-423X/5/7/007 Abstract ( 0 )   PDF (393KB) ([an error occurred while processing this directive])   The as-deposited and annealed Ge-Au film and Ge-Au/Au bilayer films have been observed by transmission electron microscopy. The bilayer with a composition of Ge-5at%Au film is amorphous, while the Ge-22at%Au film is polycrystalline. Higher concentration of Au raises the structural heterogeneity and instability. Fractals can be observed in the Ge-5at%Au/Au bilayer samples annealed at 60-100℃. The difference of the fractal patterns generated from Ge-Au/An and a-Ge/Au films call be attributed to the higher heterogeneity and instability in Ge-Au/An bilayers.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

Select

ELECTRICAL TRANSPORT BEHAVIOR OF AN Au DIFFUSE FRINGE FILM PERCOLATION SYSTEM FENG CHUN-MU, GE HONG-LIANG, YU GAO-XIANG, ZHANG QI-RUI 1996, 5 (7):  538-543.  doi: 10.1088/1004-423X/5/7/008 Abstract ( 0 )   PDF (188KB) ([an error occurred while processing this directive])   The preparation of a metallic diffuse fringe film system by dc-magnetron sputtering is described. The diffuse fringe structure of the film system is clearly observed in the SEM photograph when, during the film deposition process, the distance between the slit shutter and the substrate is large enough. Our experimental results show that the anomalous nonlinear I-V behavior of the system is mainly caused by the diffuse fringe effect. The temperature dependence of the sheet resistance is similar to that of the metallic flat film system in the temperature interval 77-300 K.

Select

FORMATION AND MAGNETIC PROPERTIES OF A NOVEL Gd3(Fe,Ti)29Ny NITRIDE B. NASUNJILEGAL, YANG FU-MING, ZHU JIAN-JUN, PAN HUA-YONG, WANG JIAN-LI, QIN WEI-DONG, TANG NING, HU BO-PING, WANG YI-ZHONG, LI HONG-SHUO, J. M. CADOGAN 1996, 5 (7):  544-551.  doi: 10.1088/1004-423X/5/7/009 Abstract ( 0 )   PDF (217KB) ([an error occurred while processing this directive])   The novel Gd3(Fe0.978Ti0.022)29 compounds and their nitride have been synthesized. The X-ray diffraction patterns of the Gd3(Fe,Ti)29Ny and its parent compounds were indexed in the Nd3(Fe,Ti)29-type structure with a monoclinic symmetry and space group P21/c, Both the nitride and the parent compounds exhibit ferrimagnetlc coupling. Nitrogenatio led to an increase in Curie temperature and saturation magnetization. The Curie temperatures are 517K for the parent and 765K for the nitride. The saturation magnetizations σs at 4.2K are 101.9A·m2/kg for the parent and 128A·m2/kg for the nitride. Both the nitride and parent exhibit a planar anisotropy. Nitrogenation led to a decrease of the contribution of Fe-sublattice to planar anisotropy. The anisotropy fields at 4.2K are 9.8T for the parent and 6.5 T for the nitride.