Table of contents

15 March 2000, Volume 9 Issue 3 Previous issue    Next issue

GENERAL

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SOME NEW AND EXACT EXPLICIT SOLUTIONS OF THE HIGHER ORDER BROER-KAUP EQUATIONS Bai Cheng-lin (白成林), Bai Cheng-jie (白成杰), Xu Bing-zhen (徐炳振) Chinese Physics, 2000, 9 (3):  161-165.  DOI: 10.1088/1009-1963/9/3/001 Abstract ( 1001 )   PDF (93KB) ( 408 )   A simple solitary wave solution and infinitely many rational function solutions, especially the closed form of the solution for the initial value problem of the higher order Broer-Kaup (BK) systems in (1+1) and (2+1) dimensions, are obtained by using the extended homogeneous balance method.

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EXPLICIT REPRESENTATION OF PLANAR WAVE SPEED AND DISPERSIVE RELATION IN GENERAL EXCITABLE MEDIA Zhou Tian-shou (周天寿), Zhang Suo-chun (张锁春) Chinese Physics, 2000, 9 (3):  166-170.  DOI: 10.1088/1009-1963/9/3/002 Abstract ( 943 )   PDF (102KB) ( 307 )   We transform the problem of seeking the planar wave speed in general excitable media into a cubically algbraic equation, thus we can find the explicit representation of the planar wave speed (in one-dimensional case, the traveling wave speed) and dispersive relation. Especially for a few typical excitable media, we give the formula for calculating the corresponding wave speed.

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INFLUENCE OF ENTANGLEMENT DEGREE ON SQUEEZING AND PHOTON ANTIBUNCHING IN THE JAYNES-CUMMINGS MODEL Ye Liu (叶柳), Guo Guang-can (郭光灿) Chinese Physics, 2000, 9 (3):  171-174.  DOI: 10.1088/1009-1963/9/3/003 Abstract ( 1115 )   PDF (136KB) ( 591 )   We consider the case that one of entangled atoms interacts with a single-mode cavity field. The atom is selectively detected after exiting the cavity, and it is found that the nonclassical properties of field states depend strongly on the entanglement degree between the two atoms. Meanwhile it is proven that squeezing of field and photon antibunching can be greatly enhanced via selective atomic measurements.

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CHAOTIC SOLITON IN COUPLED LONG JOSEPHSON JUNCTIONS Hai Wen-hua (海文华), Liu Xi-chun (刘习春), Fang Jian-shu (方见树), Huang Wei-li (黄卫立), Zhang Xi-li (张细利) Chinese Physics, 2000, 9 (3):  175-179.  DOI: 10.1088/1009-1963/9/3/004 Abstract ( 998 )   PDF (139KB) ( 463 )   The interaction between soliton and sinusoidal wave in two weakly coupled long Josephson junctions is studied. Theoretical analysis reveals that the soliton may be embedded in Melnikov chaotic attractors and the Fiske-step-modes are implied in the boundedness condition of the system. Comparison between the chaotic soliton oscillators and synchronized soliton oscillators shows that the former possesses greater maximal velocity and energy.

ATOMIC AND MOLECULAR PHYSICS

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STRETCHING VIBRATIONS OF BENZENE MOLECULE IN THE NONLINEAR MODEL Zhu Jun (朱俊), Chen Xiang-rong (陈向荣), Gou Qing-quan (芶清泉) Chinese Physics, 2000, 9 (3):  180-183.  DOI: 10.1088/1009-1963/9/3/005 Abstract ( 977 )   PDF (101KB) ( 337 )   A five-parameter nonlinear model is introduced to the description of the stretching vibrational modes of benzene molecule in the electronic ground state, and is applied for the first time to the calculations of energy levels of C-H and C-D stretches of C6H6 and C6D6 in vapor phase. The results obtained agree well with the experimental vibrational energy levels and with the results obtained from other model calculations. Moreover, our model calculations predict accurately some new overtone and combination bands that have not been studied experimentally.

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THE MID-INFRARED FREQUENCY STANDARD USING 14NmO(m=16,17,18) SPECTRAL LINES Liu Yu-yan (刘煜炎), Liu Hong-ping (刘红平), Guo Yuan-qing (郭远清), Lin Jie-li (林洁丽), Liu Xiao-yong (刘效庸), Huang Guang-ming (黄光明), Li Feng-yan (李奉延), Li Jin-rui (李津蕊) Chinese Physics, 2000, 9 (3):  184-193.  DOI: 10.1088/1009-1963/9/3/006 Abstract ( 1328 )   PDF (142KB) ( 406 )   Based on the global analysis of all available and reliable data for isotopic species 14NmO(m=16,17,18), the 14N16O rovibrational spectral lines are calculated with very high accuracy and completely agree with previous results. These lines with relative intensities can be achieved as an infrared frequency standard in the spectral range 1600-5600 cm-1. The calculated rovibrational transitions of 14NmO(m=17,18) have the same accuracy as that for 14N16O although their data are rare due to their small natural abundance.

CLASSICAL AREAS OF PHENOMENOLOGY

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NONLINEAR REFRACTION IN MULTILEVEL MOLECULAR SYSTEMS Li Chun-fei (李淳飞), Wang Yu-xiao (王玉晓), Zhang Xue-ru (张学如) Chinese Physics, 2000, 9 (3):  194-198.  DOI: 10.1088/1009-1963/9/3/007 Abstract ( 1080 )   PDF (120KB) ( 463 )   The intensity-dependent nonlinear refraction phenomena in a non-resonant multilevel molecular system is studied using rate equations in steady state, including saturable refraction, reverse saturable refraction, and the turnover between these two effects. The relationship between the refraction saturation and the optical Kerr effect is also discussed.

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

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DYNAMICS IN A DRIVEN DISORDERED VORTEX LATTICE: A NUMERICAL STUDY Cao Yi-gang (曹义刚), Jiao Zheng-kuan (焦正宽) Chinese Physics, 2000, 9 (3):  199-202.  DOI: 10.1088/1009-1963/9/3/008 Abstract ( 1089 )   PDF (116KB) ( 413 )   Using a repulsive vortex-vortex interaction model, we numerically investigate the dynamics of vortices in a driven disordered two-dimensional superconductor. At low driving forces and temperatures, we have seen the evidence of plastic and filamentary flow. At high driving forces and very low temperatures, the evidence of an ordering of the moving vortices is seen in the flux flow regime. Our results are in agreement with the previous simulation results and recent experiments.

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INTEGRABILITY OF THE SPIN-1 XXX CHAIN WITH BOUNDARY IMPURITIES AND THEIR BETHE ANSATZ Hou Bo-yu (侯伯宇), Shi Kang-jie (石康杰), Yue Rui-hong (岳瑞宏), Zhao Shao-you (赵少游) Chinese Physics, 2000, 9 (3):  203-209.  DOI: 10.1088/1009-1963/9/3/009 Abstract ( 2931 )   PDF (111KB) ( 480 )   By using the fusion method, we give the spin-1 XXX chain associated with sl2 with two arbitrary spin boundary impurities. Then the exact diagonalized Hamiltonian of this model was obtained by the means of Bethe ansatz method.

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SPECTROSCOPIC INVESTIGATION ON THE PROPERTIES OF VISIBLE AND NEAR INFRARED EMISSIONS IN Tm3+, Ho3+ Co-DOPED YVO4 CRYSTALS Wang Jin-guo (王金国), Zhang Zhi-guo (张治国), Xu Jing-zhou (许景周), Xu Ji-ren (徐积仁), Fu Pan-ming (傅盘铭), Chen Xiao-bo (陈晓波) Chinese Physics, 2000, 9 (3):  210-215.  DOI: 10.1088/1009-1963/9/3/010 Abstract ( 1084 )   PDF (166KB) ( 576 )   With the help of absorption and fluorescence spectra, the spectroscopic properties of Tm3+, Ho3+:YVO4 crystals have been investigated under different dopant concentrations. The absorption results show that the maximum absorption in the spectral range of currently available powerful laser diodes (LD) is at 796 nm, corresponding to the transition 3H6→3H4 of Tm3+ in the crystals. Upon the excitation with a LD at 808 nm, we have detected ten fluorescence bands in the spectral range spanning from visible to infrared. In visible region 4 upconversion bands have been observed centered at 475, 547, 660, and 701 nm. Discussions of the energy transfer processes suggest that cross relaxations and excited absorptions with the involvement of Tm3+ 3F4, 3H5 and Ho3+ 7I5 states are responsible for the four upconversion emissions. Comprising the relative integrated intersities of 2 μm (Ho3+: 5I7→5I8) and 1.8 μm (Tm3+: 3F_4→3H6) bands we have observed an efficient energy transfer from Tm3+ (3F4) to Ho3+ (5I7). Examination of the ratios of the intensity of 2 μm band to that of 1.8 μm band as a function of the ratios of Tm3+ concentration (cTm) to Ho3+ concentration (cHo) indicates that small concentration ratios (cTm/cHo) lead to high efficient energy transfers of Tm3+(3F4)→Ho3+(5I7).

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POSITRON STUDY OF DEFECTS IN TiNi ALLOYS Wang Jing-cheng (王景成), You Fu-qiang (尤富强), Yin Jun-lin (殷俊林), Tang Xue-feng (汤学峰), Qi Jin-lin (祁金林) Chinese Physics, 2000, 9 (3):  216-221.  DOI: 10.1088/1009-1963/9/3/011 Abstract ( 1104 )   PDF (166KB) ( 465 )   A number of TiNi samples with different compositions and states were measured by positron annihilation technique. And microdefects and the influence of them on shape memory effect were analyzed, giving some valuable information for the study of technological processes of preparing TiNi functional shape memory devices.

CROSS DISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY

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InAs SELF-ASSEMBLED NANOSTRUCTURES GROWN ON InP(001) Li Yue-fa (李月法), Liu Feng-qi (刘峰奇), Xu Bo (徐波), Lin Feng (林峰), Wu Jü (吴巨), Jiang Wei-hong (姜卫红), Ding Ding (丁鼎), Wang Zhan-guo (王占国) Chinese Physics, 2000, 9 (3):  222-224.  DOI: 10.1088/1009-1963/9/3/012 Abstract ( 839 )   PDF (800KB) ( 386 )   The 6-period stacked layers of self-assembled InAs quasi-quantum wires(qQWRs) and quantum dots(QDs) embedded into InAlAs on InP(001) substrates have been prepared by solid molecular beam epitaxy. The structures are characterized by atomic force microscopy(AFM) and transmission electron microscopy(TEM). From AFM we have observed for the first time that InAs qQWRs and QDs coexist, and we explained this phenomenon from the view of the energy related to the islands. Cross-sectional TEM shows that InAs qQWRs are vertically aligned every other layer along the growth direction [001], which disagrees with conventional vertical self-alignment of InAs QDs on GaAs substrate.

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THE RELATION BETWEEN PREEXISTING DEFECTS AND CHARGING-UP IN 9mol%Y2O3-ZrO2 STUDIED BY AUGER ELECTRON SPECLROSCOPY Guo Han-sheng (郭汉生), W. Maus-Friedrichs, V. Kempter Chinese Physics, 2000, 9 (3):  225-232.  DOI: 10.1088/1009-1963/9/3/013 Abstract ( 856 )   PDF (186KB) ( 304 )   Electron beam damage and charging process in 9mol%Y2O3-stabilized zirconia (YS-ZrO2) are studied by Auger electron spectroscopy (AES). Electron bombardment induces electron-stimulated desorption at the surface on one hand; on the other hand, it modifies the preexisting defects in the irradiated zone. Both effects will lead to charging-up of YS-ZrO2. The charging related to the first effect can be compensated by an O2 environment of 6.5×10-6 Pa, and the charging related to both effects can be inhibited by specimen heating up to 300℃. However, the modified preexisting defects will not return to their initial states prior to the radiation. Their charging behavior and charge compensation are discussed in the model of the variants of the oxygen vacancies.