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Volume 11 Issue 4
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Original Articles
Quantum Field Theory on the Universe Model of Closed Friedmann
SHEN Yougen, CHENG Zongyi, DING Haogang
Chin. Phys. Lett. 1994, 11 (4): 193-196 .  
Abstract   PDF(pc) (125KB) ( 378 )
The quantum field theory on the universe model of closed Friedmann, i. e. the third quantization, is discussed in detail, and an abnormal distribution is given which is different from Hosoya’s result.
High Order Variational-Cumulant Expansion for the 2- and 3-Dimensional Ising Model
LIU Ruijie, CHEN Tianlun
Chin. Phys. Lett. 1994, 11 (4): 197-199 .  
Abstract   PDF(pc) (135KB) ( 446 )
The variational-cumulant expansion method is applied to the 2- and 3-dimensional Ising model on the simple quadratic and cubic lattice. The model is evaluated to the seventh order. The critical temperature is given, and curves of the internal energy and specific heat are displayed for 3-dimensional case.
Energy Loss and Stopping Power of 4He Ions in mylar Foils
JIN Changwen, LU Xiting, HUANG Xiaojing, YE Yanlin, XIA Zonghuang, LIU Hongtao, JIANG Dongxing
Chin. Phys. Lett. 1994, 11 (4): 200-202 .  
Abstract   PDF(pc) (154KB) ( 515 )
The energy loss and stopping power of 4He ions in mylar foils were determined in a transmission geometry. The experimental stopping power data were compared to the previous measurements at higher energies. At lower energies, no previous measurements exist. The present results were also compared to the commonly used semiempirically theoretical predictions by Ziegler and Manoyan, and significant deviations were observed.
High Yield Synthesis of Bucky Tubules and Bucky Onions
XU Xiaoping, WANG Youwen, LI Wenzhu(Wenzhou Li)
Chin. Phys. Lett. 1994, 11 (4): 203-206 .  
Abstract   PDF(pc) (371KB) ( 445 )
The bucky tubules and bucky onions are synthesized in macroscopic quantity with high yield by modified Kratschmer-L8mb-FostiropoulogHuffman method. Besides ordinary concentric bucky tubules, also are observed abnormal nonconcentric multilayer graphitic tubules with varying layer spacings. The curved graphitic tubules are observed, showing the tendency to form torus. Under appropriate helium pressure, about half of the synthesized product is the multi-shell bucky onions, polyhedral in shape in accord with the theoretical calculation.

Water Soluble C60-Liposome and the Biological Effect of C60 to Human Cervix Cancer Cells
LI Wenzhu (Wenzhou Li), QIAN Kaixian, HUANG Wendong, ZHANG Xinxin, CHEN Wanxi
Chin. Phys. Lett. 1994, 11 (4): 207-210 .  
Abstract   PDF(pc) (377KB) ( 594 )
A preparative technique to obtain water soluble C60 -liposome by means of molecular package of C60 with lecithin has been established. The concentration of C60 presented in liposome is 1.09 x 10-4mol/dm3. The molecular system of C60 -liposome with human cervix cancer cells is irradiated with laser (570nm,800mW), there is obvious biological effect of C60 to huma cervix cancer cells.

Effect of the Cylindrical Interface Properties on Ultrasonic Transverse Wave Scattering
WANG Yaojun (Y.J.Wang), OU Xianhua, NING Wei
Chin. Phys. Lett. 1994, 11 (4): 211-214 .  
Abstract   PDF(pc) (156KB) ( 367 )
A simplified model for ultrasonic transverse wave scattering in cylindrically layered composite with thin interface layers is developed. The ultrasonic transverse wave attenuation due to the scattering in a fiber reinforced composite is found to be greatly affected by the properties of the interface layers which are simulated as viscoelastic media.
Calculation of Energetic Ion Tail from Ion Cyclotron Resonance Frequency Heating
WANG Jianguo, LI Youyi, LI Jiangang
Chin. Phys. Lett. 1994, 11 (4): 215-218 .  
Abstract   PDF(pc) (200KB) ( 381 )
The second harmonic frequency of hydrogen ion cyclotron resonance heating experiment on HT-6M tokamak was studied by adding the quasi-linear wave-ion interaction term in the two-dimensional (velocity space), time-dependent, nonlinear and multi-species Fokker-Planck equation. The temporal evolution of ion distribution function and relevant parameters were calculated and compared with experiment data. The calculation shows that the ion temperature increases, high-energy ion tail (above 5 keV) and anisotropy appear when the wave is injected to plasma. The simulations are in reasonable agreement with experiment data.
Damage Production and Annealing During MeV He Ion RBS/Channeling Analysis of GaP
LI Xiangyang, CHENG Huansheng, YANG Fujia
Chin. Phys. Lett. 1994, 11 (4): 219-222 .  
Abstract   PDF(pc) (223KB) ( 400 )
The creation of defects in GaP bombarded with MeV 4He ions has been studied under ultra-high-vacuum condition by Rutherford backscattering/channeling (RBS/C) method. Our experimental results suggest that the defect generation rate is strongly related to the surface condition. When the GaP is covered with a thin amorphous layer, a significant ion beam annealing effect Will be observed. The present results show that for GaP the damage is produced mainly by nuclear collision.
Exact Results for the Low-Energy Excitations and the Phase Transition in Slot-Janssen 1D Modulated Crystals
ZHANG Degang, YAN Fengli, LI Bozang
Chin. Phys. Lett. 1994, 11 (4): 223-226 .  
Abstract   PDF(pc) (164KB) ( 358 )
The static low-energy excitations, their stability and the undistorted-incommensurate phase transition in Slot-Janssen one-dimensional (1D) modulated crystals are studied anew in detail. The exact results are obtained.
Variational Analysis of Shape Equations for Axisymmetric Vesicles
ZHENG Weimou, LIU Jixing, HU Jianguo
Chin. Phys. Lett. 1994, 11 (4): 227-230 .  
Abstract   PDF(pc) (197KB) ( 487 )
In derivation of the shape equation for axisymmetric vesicles from the Helfrich free energy the variation must be taken with respect to the contour. It is pointed out that the widely used Helfrich shape equation and the one proposed by Peterson were derived by improper variations, hence both equations are generally incorrect. The validity of the two equations is analyzed.
Slow Positron Annihilation in Silicide Films Formed by Solid State Interaction of Co/Ti/Si and Co/Si
LIU Ping, LIN Chenglu, ZHOU Zuyao, ZOU Shichang, WENG Huiming, HAN Rongdian, LI Bingzong
Chin. Phys. Lett. 1994, 11 (4): 231-234 .  
Abstract   PDF(pc) (222KB) ( 427 )
Slow positron beam was used to investigate the solid state reaction of Co/Si and Co/Ti/Si. Variable-energy (0-20 keV) positrons were implanted into samples at different depths. The Doppler broadening of the annihilation γ-ray energy spectra measured at a number of different incident positron energies is characterized by a line-shape parameter, S. It was found that the measured S parameters are sensitive to thin film reaction and crystalline characteristics. In particular, the S parameter of epitavial CoSi2 formed by the ternary reaction is quite different from that of the polycrystalline CoSi2 formed by direct reaction of Co with Si.
Blue-Green Electroluminescence of Free-Standing Diamond Thin Films
ZHANG Binglin, SHEN Shupo, WANG Jian’en, HE Jintian, Howard R. Shanks*, Moeljanto W. Leksono*, Robert Girvan*
Chin. Phys. Lett. 1994, 11 (4): 235-238 .  
Abstract   PDF(pc) (230KB) ( 526 )
Blue-green electroluminescence has been observed in free-standing diamond films which were deposited by microwave plasma assisted CVD on silicon substrates. The electroluminescence device is driven by a 60 Hz power supply. The threshold voltage was about 112 V peak-to-peak. The electroluminescence spectrum at room temperature, showed a blue-green band with the peak centered at 485nm suggesting band A type emission. Electroluminescence was also observed at 77K.
Photoelectrochemical Behavior of the GaAs/A1xGal-xAs Superlattice Elect rode/Electrolyte Interface
LIU Yao, XIAO Xurui, LI Xueping, REN Xinmin, ZHENG Haiqun*, ZENG Yiping*, YAN Chunhui*, SUN Dianzhao*
Chin. Phys. Lett. 1994, 11 (4): 239-241 .  
Abstract   PDF(pc) (127KB) ( 419 )
Single and multiple quantum wells of lattice-matched superlattices material GaAs/A1xGal-xAs have been studied as photoelectrodes in photoelectrochemical cells containing nonaqueous electrolyte. Structured photocurrent spectra in the potential range of -1.8 to 1.0 V (vs standard calomel electrode) were obtained. The quantum yields for both superlattice electrodes were estimated and compared.
Electron-Phonon Vertex Corrections and Superconductivity in Alkali-Metal-Doped C60 Solids
XU Tiefeng*, CHEN Feng, YAN Dadong, LI Wenzhu (Wenzhou Li)
Chin. Phys. Lett. 1994, 11 (4): 242-245 .  
Abstract   PDF(pc) (165KB) ( 469 )
The narrow conduction band of C60 leads to the breakdown of the Migdal theorem and the McMillan formula is no longer applicable. In this letter, the second-order electron-phonon vertex correction is considered to explain the superconductivity in doped C60 solids and the transition temperature Tc thus obtained is in accordance with the experimental results.
Ultrafast Optical Response of Phthalocyanine Langmuir-Blodegett Film
YUAN Ping, XIA Zongju, ZOU Yinghua (Y. H. Zou), QIU Ling*, SHEN Jifeng*, SHEN Yuquan*, XU Huijun*
Chin. Phys. Lett. 1994, 11 (4): 246-249 .  
Abstract   PDF(pc) (214KB) ( 426 )
The mechanism of 2, 9, 16, 23- tetra-heptadecylamido substituted vanadyl phthalocyanine Langmuir-Blodegett film was studied with femtosecond laser pulses. An ultrafast decay due to phonon-exciton coupling greatly affected by temperature, and exciton-exciton annihilation leading to the recovery of the ground state (T~lops) and an even slower relaxation were observed.
Impulse-Coupling Coefficient of Laser-Surface Interaction in Air
MEI Liangmo, XIA Yueyuan, WANG Qingpu, XU Bingzhang, TAN Chunyu, ZHAO Shengzhi, WANG Xiangtai*, WANG Gongtang*
Chin. Phys. Lett. 1994, 11 (4): 250-252 .  
Abstract   PDF(pc) (162KB) ( 494 )
Impulse-copling coefficients, for A1 and Cu samples with finite surface area irradiated in air by 1.06 μm, 10ns laser pulses produced by a Nd: YAG laser, have been measured experimentally. A modified theoretical model of impulse-coupling is proposed, which significantly improves the agreement between the calculated impulse-coupling coefficient and the measured one.

Microstructural Characterization for Ge Clusters Embedded in a-SiNy Matrix Prepared by PECVD Method
QU Xuexuan, CHEN Kunji, WANG Mingxiang, LI Zhifeng, XIA Hua, FENG Duan
Chin. Phys. Lett. 1994, 11 (4): 253-256 .  
Abstract   PDF(pc) (258KB) ( 516 )
We report the successful synthesis of Ge clusters embedded in a-SiNy : H matrix prepared by the plasma enhanced chemical vapor deposition (PECVD) method. Chemical and microstructural characteristics of this granular thin film were analyzed using the infrared absorption, x-ray diffraction, Raman scattering, and transmission electron microscopy. Finally we discuss briefly the synthesis mechanism of this new material.
17 articles