Table of contents

20 May 1994, Volume 3 Issue 5 Previous issue    Next issue

GENERAL

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COMPLETENESS OF THE JOST SOLUTIONS IN THE CASE OF THE NLS+ EQUATION WITH NONVANISHING BOUNDARY CONDITION CHEN ZONG-YUN (陈宗蕴), HUANG NIAN-NING (黄念宁) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  321-327.  DOI: 10.1088/1004-423X/3/5/001 Abstract ( 1300 )   PDF (138KB) ( 357 )   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

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OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)1$\Pi$g, (7d)1$\Pi$g HIGH-LYING RYDBERG STATES IN Na2 PAN YONG-LE (潘永乐), DING LIANG-EN (丁良恩), MA LONG-SHENG (马龙生), SUN DIAI-PING (孙殿平), WANG ZU-GENG (王祖赓) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  328-336.  DOI: 10.1088/1004-423X/3/5/002 Abstract ( 1258 )   PDF (234KB) ( 439 )   Two 1$\Pi$g states of Na2 for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B1$\Pi$u  state are identified by the numerical calculations with the molec-ular constants for B1$\Pi$u←X1$\Sigma$g+ transitions and confirmed by the complemen-tary A1$\Sigma$g+←X1$\Sigma$g+ polarization spectra. Absolute vibrational numberings of the (6d)1$\Pi$g and (7d)1$\Pi$g 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)1$\Pi$g, (7d)1$\Pi$g states are reported.

CLASSICAL AREAS OF PHENOMENOLOGY

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EXPERIMENTAL STUDY OF DIFFRACTIVE PROPERTIES OF WAVELENGTH-SIZED SINGLE GROOVE IN Si-Si3N4 SUBSTRATE Lü Hui-bin (吕惠宾), R.E.Burge, D.N.Qu, X.Yuan Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  337-344.  DOI: 10.1088/1004-423X/3/5/003 Abstract ( 1181 )   PDF (192KB) ( 359 )   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.

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THREE-DIMENSIONAL ANALYSIS OF ELECTROMAGNETICALLY PUMPED FREE-ELECTRON-LASER QIAN BAO-LIANG (钱宝良), LIU YONG-GUI (刘永贵) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  345-352.  DOI: 10.1088/1004-423X/3/5/004 Abstract ( 1110 )   PDF (173KB) ( 493 )   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

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PERIODIC WINDOWS AND CHAOTIC TRANSIENT IN COUPLED MAP LATTICES QU ZHI-LIN (屈支林), XU CHANG-YE (徐昌业), MA BEN-KUN (马本堃), HU GANG (胡岗) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  353-359.  DOI: 10.1088/1004-423X/3/5/005 Abstract ( 1624 )   PDF (159KB) ( 609 )   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

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A DOUBLE-TEMPERATURE-GRADIENT TECHNIQUE FOR THE GROWTH OF PURE C60 SINGLE CRYSTALS FROM THE VAPOR PHASE WANG GANG (王刚), XIE SI-SHEN (解思深), LIU WEI (刘维), FU CHUN-SHENG (傅春生), LI CHAO-RONG (李超荣), WANG CHANG-QING (王昌庆), LI NAN (李楠), QIAN SHENG-FA (钱生法), ZHANG ZE-BO (张泽勃), YU YU-DE (俞育德), ZHOU WEI-YA (周维亚) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  360-365.  DOI: 10.1088/1004-423X/3/5/006 Abstract ( 1318 )   PDF (233KB) ( 413 )   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

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INFLUENCE OF SPIN AND CHARGE FLUCTUATIONS ON THE HIGH-Tc SUPERCONDUCTIVITY XIAO MING-WEN (肖明文), XU XIAO-HUA (徐晓华), LI ZHENG-ZHONG (李正中) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  366-373.  DOI: 10.1088/1004-423X/3/5/007 Abstract ( 1056 )   PDF (211KB) ( 385 )   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 $\Delta$(0), the superconducting gap at T=0, and therefore, enhances the ratio 2$\Delta$(0)/Tc. This provides a reasonable physical interpretation for the relevant experimental results.

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LOW-TEMPERATURE LOW-FREQUENCY DIELECTRIC RELAXATIONS IN VDF(81)/TeFE(19) COPOLYMERS ZHANG XING-YUAN (张兴元), TAKEO FURUKAWA Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  374-383.  DOI: 10.1088/1004-423X/3/5/008 Abstract ( 1285 )   PDF (293KB) ( 577 )   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.

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WELL-WIDTH DEPENDENCE OF THE EXCITON LIFETIME IN GaAs/AlGaAs QUANTUM WELLS JIN SHI-RONG (金世荣), XU ZHONG-YING (徐仲英), LUO JIN-SHENG (罗晋生), LUO CHANG-PING (罗昌平), XU JI-ZONG (许继宗), ZHENG BAO-ZHEN (郑宝真) Acta Physica Sinica (Overseas Edition), 1994, 3 (5):  384-389.  DOI: 10.1088/1004-423X/3/5/009 Abstract ( 1306 )   PDF (183KB) ( 480 )   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.