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Chin. Phys. B  
  Chin. Phys. B--1994, Vol.3, No.5
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GENERAL

COMPLETENESS OF THE JOST SOLUTIONS IN THE CASE OF THE NLS+ EQUATION WITH NONVANISHING BOUNDARY CONDITION

CHEN ZONG-YUN, HUANG NIAN-NING
Chin. Phys. B 1994, 3 (5): 0321;  doi: 10.1088/1004-423X/3/5/001
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In the case of the NLS+ equation with nonvanishing boundary condition, a complete set of the Jost solutions is chosen, and its completeness is shown by means of the Marchenko inverse scattering equation.
ATOMIC AND MOLECULAR PHYSICS

OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)1Πg, (7d)1Πg HIGH-LYING RYDBERG STATES IN Na2

PAN YONG-LE, DING LIANG-EN, MA LONG-SHENG, SUN DIAI-PING, WANG ZU-GENG
Chin. Phys. B 1994, 3 (5): 0328;  doi: 10.1088/1004-423X/3/5/002
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Two 1Πg states of Na2 for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B1Πu state are identified by the numerical calculations with the molec-ular constants for B1Πu←X1Σg+ transitions and confirmed by the complemen-tary A1Σg+←X1Σg+ polarization spectra. Absolute vibrational numberings of the (6d)1Πg and (7d)1Πg states are determined by comparing the experimental OODR excitation intensities with the simulated Franck-Condon factors. The Dnnham coef-ficients and the Rydberg-Klein-Rees (RKR) potential energy curves of the (6d)1Πg, (7d)1Πg states are reported.
CLASSICAL AREAS OF PHENOMENOLOGY

EXPERIMENTAL STUDY OF DIFFRACTIVE PROPERTIES OF WAVELENGTH-SIZED SINGLE GROOVE IN Si-Si3N4 SUBSTRATE

Lü Hui-bin, R.E.Burge, D.N.Qu, X.Yuan
Chin. Phys. B 1994, 3 (5): 0337;  doi: 10.1088/1004-423X/3/5/003
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Experimental results are presented for the diffractive properties of wavelength-sized single groove in Si-Si3N4 substrate. The experimental results show that the diffraction of wavelength-sized single grooves in a non-perfectly conducting material is more complex than that of perfectly conducting material. The diffraction intensities change with the change of polarization angle of the incident light. The diffraction intensities for TM polarization light are larger as the groove width is larger. The diffraction intensities of TM polarization light decrease gradually and that of TE polarization light increase gradually when the groove width is close to the wavelength of the incident light. The variations of diffraction intensities are quite different not only for various grooves with different widths but also for different diffraction angles for the same groove. Although the intensity variation of each diffraction order has a very regular sinusoidal dependence on the polarization angles of the incident light, the variation phase of each diffraction order is not all the same.

THREE-DIMENSIONAL ANALYSIS OF ELECTROMAGNETICALLY PUMPED FREE-ELECTRON-LASER

QIAN BAO-LIANG, LIU YONG-GUI
Chin. Phys. B 1994, 3 (5): 0345;  doi: 10.1088/1004-423X/3/5/004
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An analysis of the electromagnetieally pumped free-electron-laser, which includes a solid relativistic electron beam and a cylindrical waveguide, is presented in this paper. Linear and nonlinear dispersion relations are derived. The mode structure is investigated and the instability growth rates are formulated for both the Raman regime and high-gain Compton regime. The results show that the growth rates closely depend on the amplitude and fre-quency of the pump wave, the electron density, and the electron energy. The growth rates are also related to the radii of the electron beam and waveguide, as well as the structure of coupled modes. The growth rates can be greatly enhanced as long as reasonable parameters are chosen. In addition, a comparison of theoretical and experimental results is finally given in the present paper.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

PERIODIC WINDOWS AND CHAOTIC TRANSIENT IN COUPLED MAP LATTICES

QU ZHI-LIN, XU CHANG-YE, MA BEN-KUN, HU GANG
Chin. Phys. B 1994, 3 (5): 0353;  doi: 10.1088/1004-423X/3/5/005
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A class of special periodic windows in coupled Logistic lattice and its bifurcation behaviors versus the coupling strength are investigated, The system has long chaotic transient and the average transient length increases exponentially with respect to the system size.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

A DOUBLE-TEMPERATURE-GRADIENT TECHNIQUE FOR THE GROWTH OF PURE C60 SINGLE CRYSTALS FROM THE VAPOR PHASE

WANG GANG, XIE SI-SHEN, LIU WEI, FU CHUN-SHENG, LI CHAO-RONG, WANG CHANG-QING, LI NAN, QIAN SHENG-FA, ZHANG ZE-BO, YU YU-DE, ZHOU WEI-YA
Chin. Phys. B 1994, 3 (5): 0360;  doi: 10.1088/1004-423X/3/5/006
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Pure C60 single crystals were grown by a sublimation-condensation method in an evacuated dosed quartz tube situated in a double-temperature-gradient furnace. Large C60 single crystals, up to a size of 0.6 mm×1.0 mm×2.0 mm with quite smooth and shiny faces, were obtained. X-ray diffraction, electron diffraction and X-ray morphology were carried out and showed that the quality of large C60 single crystals grown by the double-temperature-gradient technique is excellent. In this paper the experimental results of the growth of large C60 single crystals are reported and the morphological and structural characterizations are discussed in detail.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

INFLUENCE OF SPIN AND CHARGE FLUCTUATIONS ON THE HIGH-Tc SUPERCONDUCTIVITY

XIAO MING-WEN, XU XIAO-HUA, LI ZHENG-ZHONG
Chin. Phys. B 1994, 3 (5): 0366;  doi: 10.1088/1004-423X/3/5/007
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In the framework of the weak coupling theory of superconductivity, we have proved that spin and charge fluctuations in the high-Tc superconductors can pro-duce respectively, pair-breaking and pair-forming effects on the superconductivity resulting from the "generalized BCS mechanism". With the coupling constant for spin fluctuations larger than that for charge fluctuations, they combine to produce a temperature-dependent effective pair-breaking effect, which makes Tc decrease more rapidly than Δ(0), the superconducting gap at T=0, and therefore, enhances the ratio 2Δ(0)/Tc. This provides a reasonable physical interpretation for the relevant experimental results.

LOW-TEMPERATURE LOW-FREQUENCY DIELECTRIC RELAXATIONS IN VDF(81)/TeFE(19) COPOLYMERS

ZHANG XING-YUAN, TAKEO FURUKAWA
Chin. Phys. B 1994, 3 (5): 0374;  doi: 10.1088/1004-423X/3/5/008
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The complex dielectric constants of ferroelectric copolymers VDF(81)/TeFE(19) with dif-ferent crystallinities have been measured over the range of-120- +40℃ and 10-2-10-4 Hz, using an improved dielectric relaxation spectrometer. The low-temperature processes of di-electric relaxation show that the frequency spectra of copolymers below room temperature consist of two parts: a low-frequency component which accords with a WLF equation and is ascribed to the micro-Brownian motions of frozen-in segments in the noncrystalline regions, and a high-frequency component which follows an Arrhenius rule and is designated as the local motions of small-scale segments in the crystalline and/or noncrystalline regions. The calculated results indicate that Tg of copolymers is -52℃ and the activation energy of local relaxation is 37.7 kJ/mol.

WELL-WIDTH DEPENDENCE OF THE EXCITON LIFETIME IN GaAs/AlGaAs QUANTUM WELLS

JIN SHI-RONG, XU ZHONG-YING, LUO JIN-SHENG, LUO CHANG-PING, XU JI-ZONG, ZHENG BAO-ZHEN
Chin. Phys. B 1994, 3 (5): 0384;  doi: 10.1088/1004-423X/3/5/009
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The dependence of the excitonic lifetime on the well width has been studied in conventional GaAs/AlGaAs quantum wells. Two clearly different variations of the measured excitonic lifetime have been observed. For wide well widths, we find a nearly linear decrease of the lifetime with decreasing well width. However, when the well is further decreased, a saturation and even increase of the lifetime with decreeing well width are observed. The experimental data are compared with the theory of radiative excitonic recombination, and show that well width dependence of the measured photoluminescence lifetime can be attributed mainly to the change of the excitonic effective volume and the overlap integral as well.
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