Table of contents

20 September 1994, Volume 3 Issue 9 Previous issue    Next issue

GENERAL

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A NEW DIRECT METHOD FOR HEAT KERNEL EXPANSION IN CURVED SPACE AND THE RESUMMED FORM OF NONDERIVATIVE TERM XU DIAN-YAN (许殿彦) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  641-652.  DOI: 10.1088/1004-423X/3/9/001 Abstract ( 1199 )   PDF (217KB) ( 361 )   A new method is proposed for heat kernel expansion in curved space, without using the recursion relation. The existence of the resummed form of nonderivative terms arising out of X from the operator A =-□+ X is proved. The De Witt-Seeley-Gilkey coefficients E2(x) and E4(x) are derived.

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THE UNIVERSAL TRANSITION OF PLATEAU STRUCTURE OF LYAPUNOV EXPONENTS WANG BING-HONG (汪秉宏), CHEN GUO-YI (陈国义), GU GUO-QING (顾国庆) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  653-666.  DOI: 10.1088/1004-423X/3/9/002 Abstract ( 1218 )   PDF (285KB) ( 467 )   The universal transition of Lyapunov exponents between conservative limit and dissipa-tire limit of nonlinear dynamical system is studied. It is discovered numerically and proved analytically that for homogeneous dissipative two-dimensional maps, along the equal dissi-pation line in parameter space, the Lyapunov exponents of attractor orbits possess a plateau structure and strict symmetry about its plateau value, The ratios between the plateau width and the stable window width of period 1-4 orbits for Henon map are calculated. The result shows that the plateau structure of Lyapunov exponents remains invariant for the attractor orbits belonging to a period doubling bifurcation sequence. This fact reveals a new universal transition behavior between order and chaos when the dissipation of the dynamical system is weakened to zero.

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INHOMOGENEOUS FLUCTUATION DISTRIBUTION IN THE OUTPUT OF STOCHASTIC RESONANCE SYSTEMS AND ITS APPLICATION WEN XIAO-DONG (温孝东), HU GANG (胡岗), YANG CHUN-YUAN (杨春元), LI RONG (李蓉), GONG DE-CHUN (龚德纯), WANG FU-ZHONG (王辅忠) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  667-675.  DOI: 10.1088/1004-423X/3/9/003 Abstract ( 1375 )   PDF (235KB) ( 648 )   Inputting a periodic signal mixed with white noise into a bistable system, we find that the fluctuation distribution in the time series of the output is strongly inhomogeneous. In certain phase part fluctuation is very low under the stochastic resonance condition, and consequently, the signal-to-noise ratio (SNR) there is much higher than that of the input. This mechanism can be used to design a nonlinear receiver to extract the signed from noise with SNR three times higher than the largest SNR obtained so far by the optimal linear filter.

CLASSICAL AREAS OF PHENOMENOLOGY

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LIGHT-INDUCED ABSORPTION ENHANCEMENT IN C60 TOLUENE SOLUTION ZHAO JIANG (赵江), ZHANG ZHAN-XIANG (张占祥), YE PEI-XIAN (叶佩弦), XIE SI-SHEN (解思深), ZHANG ZE-BO (张泽勃), ZHENG YOU-FENG (郑幼风) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  676-681.  DOI: 10.1088/1004-423X/3/9/004 Abstract ( 1252 )   PDF (171KB) ( 340 )   Absorption enhancement induced by a pump beam of 532 nm in C60 toluene solution has been observed and studied from 560nm to 63Onm, and the absorption cross section of its lowest triplet state has been determined in this wavelength range according to our theoretical model.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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INVESTIGATION ON THE COMPOSITION AND STRUCTURE OF SILICON NITRIDE FILM PREPARED BY ECR-PECVD CHEN JUN-FANG (陈俊芳), CHENG SHAO-YU (程绍玉), REN ZHAO-XING (任兆杏), ZHANG SU-QING (张束清), NING ZHAO-YUAN (宁兆元), WU XUE-MEI (吴雪梅) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  682-689.  DOI: 10.1088/1004-423X/3/9/005 Abstract ( 1289 )   PDF (238KB) ( 438 )   In this paper, the effect of temperature on the composition and structure of the Si3N4 thin film is investigated. X-ray diffraction pattern and transmission electron microscope (TEM) analyses show that the Si3N4 film undergoes the transition from amorphous to crystalline phase with increasing deposition temperature. Infra-red qualitative analysis shows that the content of hydrogen decreases with increasing deposition temperature.The stoichiometric of Si3N4 is investigated by X-ray photoelectron spectroscopy or electron spectroscopy for chemical analysis.

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MONTE CARLO SIMULATION OF THE ION BEAM ENHANCED DEPOSITION OF SILICON NITRIDE FILMS SHAO QI-YUN (邵其鋆), PAN ZHENG-YING (潘正瑛) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  690-696.  DOI: 10.1088/1004-423X/3/9/006 Abstract ( 1161 )   PDF (186KB) ( 413 )   In this paper, the growth process of silicon nitride films by ion beam enhanced depo-sition (IBED) is investigated by using the dynamic Monte Carlo simulation, which is based on the binary collision approximation. The effects of the incident angles, energies of the bombarded ions and the interaction potentials on the composition of the films are discussed. The successive and alternate deposition process of silicon and implantation of nitrogen ions have been applied to simulate the actual continuous and synchronous process of IBED. The relationship between the calculated composition of the films and the ion/atom arrival ratio of implanted nitrogen ions to deposited silicon atoms has been established. The composition profile obtained by computer simulation is in good agreement with the experimental results.

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

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THERMALLY ACTIVATED HOPPING IN Dy1-xPrxBa2Cu3O7-$\delta$ SYSTEM CAO XIAO-WEN (曹效文) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  697-701.  DOI: 10.1088/1004-423X/3/9/007 Abstract ( 1267 )   PDF (152KB) ( 344 )   The temperature dependence of resistivity in Dy1-xPrxBa2Cu3O7-$\delta$ system with x>0.6 was measured. The experimental results show that Pr substitution leads to the localization of mobile holes and such a localization is enhanced with increasing Pr concentration. The gradually enhancing of localization induces Anderson transitions one by one in this system, including the transition from the conduction by excitation of holes to the one by thermal activation hopping between localized states, the so called Anderson transition type-I, and the transition from nearest neighbor hopping (NNH) to variable range hopping (VRH), the Anderson transition type-II, and the Anderson transition type-lI from 3D to 2D.

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THE CRYSTALLIZATION OF Bi IN THE ANNEALED a-Ge/Bi BILAYER AND ITS EFFECT ON CONDUCTIVITY LI YU-ZI (李玉芝), LI TIE (李铁), XU CUN-YI (许存义), ZHOU GUI-EN (周贵恩), ZHANG YU-HENG (张裕恒) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  702-707.  DOI: 10.1088/1004-423X/3/9/008 Abstract ( 1213 )   PDF (140KB) ( 380 )   In this paper, the crystallization behaviors and transport properties are investigated for a-Ge/Bi bilayers annealed at different temperatures. For 200nm/100nm bilayers, it is found that the orientations of Bi in the bilayers annealed at 200℃ and 340℃ are preferred, as well as the original one. But they are random when the bilayers are annealed at tem-peratures between 240℃ and 300℃. For 200nm/50nm bilayers, the orientation of Bi are always preferred. Corresponding to the orientations mentioned above, the minimum on the R(300K)-Ta curve appears only in the case of 200nm/100 nm bilayers.

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LOW-FIELD MICROWAVE SIGNAL IN UNDOPED AND Sb-DOPED Bi-Pb-Sr-Ca-Cu-O HOU BI-HUI (侯碧辉), WANG MEI-SHENG (王梅生), CHEN ZHAO-JIA (陈兆甲), XU QIN-LUN (许勤论), JIN TONG-ZHENG (金通政) Acta Physica Sinica (Overseas Edition), 1994, 3 (9):  708-711.  DOI: 10.1088/1004-423X/3/9/009 Abstract ( 1076 )   PDF (129KB) ( 409 )   Non-resonant low-field microwave signal in undoped Bi-Pb-Sr-Ca-Cu-O (2223) sample inches monotonously with decreasing temperature, like that in many bulk samples of high-Tc superconductor. But the signed of a Sb-doped sample shows a peak at 103K, and declines gradually and tends to stabilize when the temperature is further reduced. A distorted 2223 phase (i.e., 130K phase) which was an intergrowth of 2223 and insulating monoclinic phases in the Sb-doped sample, was unstable, and it might change into the stable insulating monoclinic phase and lost its superconductivity at lower temperatures.