| 1. |
- Cao, X., et al.
(författare)
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Comparative studies on annealed proton exchange waveguides in Y-cut MgO : LiNbO3 and Z-cut LiNbO3
- 2004
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Ingår i: Wuli xuebao. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 53:11, s. 3786-3793
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Tidskriftsartikel (refereegranskat)abstract
- Proton exchange waveguides in MgO:LiNbO.3 and LiNbO.3 crystals were fabricated , and the diffusion coefficients for the proton exchange process are obtained. The evolution characteristics of the waveguide index profile in the annealing process are studied. The structural deformation of the proton exchange waveguides in Mg O:LiNbO.3 and LiNbO.3 and the restoration effect of annealing are also studied tho roughly by the x-ray diffraction method and the OH-infrared absorption method. The optical and structural characteristics of annealed proton exchange waveguides in MgO:LiNbO.3 and LiNbO.3 are analysed and compared with eath other.
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| 2. |
- Chen, L., et al.
(författare)
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Analysis for the propagation of evanescent waves and the photo tunneling effect in a multi-layered structure containing materials with negative refractive index
- 2003
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Ingår i: Wuli xuebao. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 52:10, s. 2386-2392
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Tidskriftsartikel (refereegranskat)abstract
- The propagation properties of evanescent waves in a multi-layered structure containing materials with negative refractive index are analyzed. The decay or magnification of the amplitude of evanescent waves in different situations is explained analytically in detail. In particular, the influence of the dissipation of the negative refractive index medium on the photon tunneling effect is discussed. The propagation and energy storage of evanescent waves are shown clearly by using the incidence of a Gauss beam.
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| 3. |
- Chen, Xiangrong, 1982, et al.
(författare)
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Study on conducting characteristics of electrical trees in cross-linked polyethylene cable insulation
- 2012
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Ingår i: Wuli Xuebao/Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 61:8, s. Art. no. 087701-
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Tidskriftsartikel (refereegranskat)abstract
- The conducting characteristics of two typical electrical trees in cross-linked polyethylene (XLPE) cable insulation are studied by a combination of optical microscopy observation, partial discharge measurement and con-focal Raman spectroscopy analysis. Although they are grown under similar conditions, these two trees display very different shapes. One is a typical branch-pine tree grown at 9 kV, and the other is a branch tree grown at 11 kV. The growth and the partial discharge regularities show obvious differences. The disordered graphitic carbon is condensed in the main tree channels of the branch-pine tree. From the relative intensity of the graphitic carbon G band to D band, the graphitic domain is estimated to be about 8 nm in size. The tree channel resistance per unit length is less than 10 Ω· μm-1, which is sufficient to prevent the partial discharge from developing within the tree structure. The branch-pine tree shows the features of the conducting tree. The fluorescence background is observed in the channels of branch tree, which shows the existence of the products of the material degradation, but no disordered graphitic carbon is observed in these tree channels. These tree channels display obvious non-conducting characteristics, which is not sufficient to prevent the continuous effect of the partial discharges. Finally, a single channel growth model is proposed for the conducting and non-conducting trees grown in XLPE cable insulation. Based on the equivalent circuit theory, the growth mechanisms of the two trees with different conducting characteristics in XLPE cable insulation are discussed.
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| 4. |
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| 5. |
- Cheng, C., et al.
(författare)
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Optimization and elimination of black center of a large-bore copper vapor laser
- 2000
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Ingår i: Wuli xuebao. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 49:7, s. 1267-1272
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Tidskriftsartikel (refereegranskat)abstract
- Applying a genetic algorithm and taking the maximum output as an objective funct ion, a copper vapor laser with about 100W output is optimized and designed for reducing the “black center” of the radial laser intensity. The “black center ”, which results from the skin effect of the continuing pulsed field, is reduce d and the output is increased significantly by optimizing the laser tube radius- length and the LC circuit parameters.
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| 8. |
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| 9. |
- Ha, S., et al.
(författare)
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Transmission of low-energy Cl- ions through Al2O3 insulating nanocapillaries
- 2020
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Ingår i: Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 69:9
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Tidskriftsartikel (refereegranskat)abstract
- The transmission of 10-keV Cl- ions through Al2O3 insulating nanocapillaries is studied both by experiment and simulation. The double-peak structure in the transmitted angular distribution is found to be the same as our previous result. The peak around the direction of the primary beam is caused mainly by the directly transmitted Cl-, and the other peak around the tilt angle of Al2O3 nanocapillaries is mainly induced by Cl+ and Cl-0. The intensity of transmitted Cl- decreases with the tilt angle increasing, which is in accord with the geometrically allowed transmission. Beyond the geometrically allowed angle, the transmitted projectiles are mainly Cl+ ions and Cl-0 atoms. The ratio of transmitted Cl+ ion to Cl-0 atom drops as tilt angle increases, and it turns more obvious when the tilt angle is larger than the limit of the geometrical transmission. A detailed physics process was developed within Geometry and Tracking 4 (Geant4) to perform the trajectory simulation, in which the forces from the deposited charges and the image charges, the scattering from the surfaces as well as the charge exchange are taken into consideration. The transmissions at the tilt angle of 1.6 degrees are simulated for the cases without and with deposited charges of -100 e/capillary. For the deposition charge quantity of -100 e/capillary, the majority of the transmitted projectiles are mainly the directly transmitted Cl- ions exiting to the direction of tilt angle, and the transmitted Cl-0 and Cl+ account for a very small portion. While for the case with no deposited charges, the simulation results agree well with the experimental results. The dependence of the scattering process on the tilt angle, which results in the different features in the transmitted projectiles, is studied in detail by the simulation. It is found that the transmitted Cl-0 atoms exit through single to multiple scattering, and most of transmitted Cl-0 atoms exit through single and double scattering, and are centered along the axis of nanocapillaries, while Cl+ ions mainly exit by single scattering, which results in the fact that the intensity of the transmitted Cl-0 atoms drops slower than that of the transmitted Cl+ ions with the increase of the tilt angle, leading the ratio of the transmitted Cl+ to Cl-0 to decrease as the tilt angle increases in experiment. Our results describe the physical mechanism of low-energy ions through insulating nanocapillaries in detail, i.e. how the scattering process dominates the final transmission. It is found that the transmission of the negative ions in the energy range above 10 keV is caused by the scattering and the charge exchange process.
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| 10. |
- He, Sailing, et al.
(författare)
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Synchrotron radiation photoemission study of Yb2.75C60
- 2005
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Ingår i: Wuli xuebao. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 54:3, s. 1400-1405
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Tidskriftsartikel (refereegranskat)abstract
- The Yb275C60 thin film was prepared and studied by using the synchrotron radiation ultraviolet photoemission spectroscopy(PES) in an ultrahighvacuum system. The spectral line obtained in the range between the Fermi level and ～5 eV binding energy consists of those lines from the valence band (the molecular orbital LUMO, HOMO and HOMO1 derived energy bands of C60) and core levels(Yb 4f7/2 and 4f5/2). Taking into account the variations of the photoinization cross sections of C 2p and Yb 4f with different photon energies, we have measured the photoemission spectra under the condition of varying photon energies, and carried out simulations to deduce the component contributions. The peak positions, widths and intensities for the components are obtained quantitatively. The results reveals that the photoemission of 4f electrons has a significant intensity with the photon energies larger than ～300 eV, and that the measured spectra depart drastically from the density of states of the valence band. To observe the valence band structure, one should carry out the PES measurements by using photons with energies less than 300 eV. The photoionization crosssection oscillation is also observed in Yb275C60 with almost the same oscillation period as that for pure C60 However, the oscillation amplitude is obviously smaller than that for pure C60, which reveals that the chemical environment of C60 in compounds has nonnegligible effects on the photoionization crosssection oscillation phenomenon.
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