中国物理B

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GENERAL SOLITON SOLUTIONS OF THE NLS⁺ EQUATION UNDER NON-VANISHING BOUNDARY CONDITION

陈宗蕴, 李再光, 黄念宁

1994 (1): 1-17. doi: 10.1088/1004-423X/3/1/001

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For the NLS⁺ equation under nonvanishing boundary condition, to avoid complexity due to Riemann surface, required for double-valued function of the usual spectral parameter, starting from a particular auxiliary spectral parameter, a special inverse scattering method is systematically developed, and explicit expressions of the general multi-soliton solutions are successfully obtained. Asymptotic behaviors of the muiti-soliton solutions, additional displacement of center and additional phase shift of the peak are derived. When the boundary value approaches zero, all the formulas become the known ones naturally.

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GENERAL SOLITON SOLUTIONS OF THE COUPLED SCALAR FIELDS

海文华

1994 (1): 18-25. doi: 10.1088/1004-423X/3/1/002

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Let σ and ρ be two field variables of the n-dimensional coupled scalar fields. Taking the function transformations σ=σ(ξ) and ρ=ρ(ξ) leads to an equation F(σ,ρ,dσ/dρ,d²σ/d²ρ) =0. Inserting any solution of this equation into the field equations yields a pair of general soliton solutions σ=σ(ξ) and ρ=ρ[σ(ξ)]. Some interesting specific soliton solutions are given. The stability and other properties of these solitons are discussed.

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THE PROCESS OF SPACE CURRENT NEUTRALIZATION OF INTENSE RELATIVISTIC ELECTRON BEAM UNDER AN EXTERNALLY APPLIED MAGNETIC GUIDE FIELD

刘国治, 刘乃泉, 谢羲

1994 (1): 26-35. doi: 10.1088/1004-423X/3/1/003

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The process of space current neutralization of intense relativistic electron beam under an externally applied magnetic guide field is discussed in this paper. Ionization by electron avalanching and by beam electrons impact and recombination is included in the calculation of plasma density buildup, with plasma heating by return current and two- stream instability taken into account. A code to evaluate the process of space current neutralization was set up. The calculations demonstrate that the optimum gas pressure increases as peak beam current increases and it decreases as the risetime of beam pulse increases.

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STUDY ON THE MAGNETIC COMPRESSION OF INTENSE RELATIVISTIC ELECTRON BEAMS UNDER A CONVERGING MAGNETIC GUIDE FIELD

刘国治, 刘乃泉, 谢羲, 邱爱慈, 樊亚军, 张嘉生

1994 (1): 36-44. doi: 10.1088/1004-423X/3/1/004

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The magnetic compression of intense relativistic electron beams under a converging magnetic guide field is studied theoretically and experimentally in this paper. A code to evaluate the compressed-beam transport is set up. Calculations of the beam energy fraction transmitted through magnetic mirror are in good agreement with experimental data.

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EXPERIMENTAL STUDY ON THE UNIFORMITY OF LARGE AREA INTENSE RELATIVISTIC ELECTRON BEAMS

刘国治, 邱爱慈, 张嘉生, 刘乃泉, 谢羲

1994 (1): 45-50. doi: 10.1088/1004-423X/3/1/005

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The uniformity of intense relativistic electron beams under a converging magnetic guide field is studied experimentally in this paper. In the experiments, fluence calorimeter and X-ray pinhole photograph were used to measure the beam uniformity. The experimental results show that the externally applied magnetic flux density at the cathode and the shape of cathode face have considerable influence on the beam uniformity, The beam uniformity better than 80% is obtained over an area of 200cm² when the externally applied magnetic flux density at the cathode is about 0.6T and the cathode face is concave to a depth of 1.5 mm, relative to the cathode edge.

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EFFECTS OF THE HUBBARD INTERACTIONS AND ELECTROSTATIC PINNING ON THE 2D LOCALIZED MODES OF TRANS-(CH)_x AROUND A SOLITON

姚凯伦, 李占杰, 邢彪

1994 (1): 51-55. doi: 10.1088/1004-423X/3/1/006

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The electron-lattice coupling vibrational modes are calculated using a two-dimensional ex-tension of the Su-Schrieffet-Heeger model that includes the bond-bending term, the electron-electron interactions and the electrostatic pianing for doped samples, The result shows that all ten localized modes exist after turning on the e-e interactions and doped pinning effects, but their localizations has been strengthened and the frequencies have been moved slightly.

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ELECTRONIC PROPERTIES FOR A CLASS OF ONE-DIMENSIONAL QUASILATTICES

黄秀清, 莫党, 刘有延

1994 (1): 56-63. doi: 10.1088/1004-423X/3/1/007

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We have studied a new class of one-dimensional quasiperiodic lattices, for which the substitution rules are B→BA, and A→BAB. The Kohmoto-Kadenoff-Tang (KKT) renormalization group method has been used to study the asymptotical behavior of the spectrum. It is found that the energy spectra are Cantor-like but have different salf-similarity from that of Fibonacci lattice. By use of several different criteria, three kinds of wave function behavior (extended, localized, and intermediate states) are clearly observed.

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PREPARATION, SUPERCONDUCTIVITY AND STRUCTURE OF THE LaBaCaCu₃O_7-x SUPERCONDUCTORS WITH T_c HIGHER THAN 80 K

车广灿, 杜玉扣, 贾顺莲, 杨晔, 赵忠贤

1994 (1): 64-70. doi: 10.1088/1004-423X/3/1/008

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In this paper, the preparation process of the tetragonal LaBaCaCu₃O_7-x (LBCCO) superconductor with T_c=84 K is repored. The superconductivity and structure of the LBCCO superconducting phase are investigated by means of X-ray diffraction (XRD), transmission electron microscope(TEM) and superconductivity measurements, The results indicate that the superconducting phase with T_c=82K in the LBCCO system has a tetragonal structure with a=0.3966nm, c=l.1838nm and space group P4/mmm. About 50% of the Ca and La atoms are located in 1d sites (i.e. Y site in the YBCO structure). It is confirmed that there is in fact no orthorhombic to tetragonal transition in this material. The relationship between the oxygen content and T_c is also presented.

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