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91.
V.R. Romanovskii 《Physica C: Superconductivity and its Applications》2009,469(14):832-838
The influence of non-uniform temperature distribution in the cross section of a high-temperature superconductor (thermal size effect) on its voltage–current characteristic and the instability conditions of charged current is investigated. The boundary values of the electric field and the current above which the charged current is unstable are defined taking into account the size effect. It is shown that the calculated current of the instability determining the maximum allowable value of the charged current is reduced, if the thermal heterogeneity of the electrodynamics states is taken into consideration in the theoretical analysis of the stability conditions. As a result, the limiting stable values of the electric field and current depend nonlinearly on the thickness of the superconductor, its critical properties as well as on the external cooling conditions. Therefore, the current of instability will not increase proportionally to the increase in the thickness of superconductor or its critical current density at the intensive cooling conditions. 相似文献
92.
J. Piqueras B. Méndez R. Plugaru G. Craciun J.A. García A. Remón 《Applied Physics A: Materials Science & Processing》1999,68(3):329-331
Received: 4 May 1998 / Accepted: 30 October 1998 相似文献
93.
C. Corsi M. Inguscio S. Chudzynski K. Ernst F. D’Amato M. De Rosa 《Applied physics. B, Lasers and optics》1999,68(2):267-269
Sensitivity studies are also performed, to evaluate the minimum detectable concentration of HCl in air.
Received: 7 August 1998/Revised version: 5 October 1998 相似文献
94.
Guchang Han Yugui Wang Hanmin Han Zhihe Wang Shunxi Wang Weifan Yuan Qiaolin Huang Zhiming Liu Jinlin Chen 《Applied Physics A: Materials Science & Processing》1993,57(4):363-366
The transport critical current properties of Bi(2223) silver-clamped thick films are studied by the measurement of its dependence on magnetic field and temperature close to T
c. It is found that the transport critical current follows a power law J
c(1–T/T
c)3/2 for the sample with J
c>2.0×104 A/cm2 (77K, zero field) and that J
c(H) is basically reversible for increasing and decreasing magnetic field. After the transport current exceeds the critical current, the voltage-current (V-I) characteristics show a flux-creep-like behaviour until they smoothly join the flux-flow state. From the measurement of V-I curves, the pinning property of the sample may be estimated using the flux-creep mode. The flux-flow resistance is found to have a nonlinear magnetic field dependence. 相似文献
95.
Cd0.9Mn0.1S semiconductor nanorods were successfully prepared by the hydrothermal reaction of CdCl2·2.5H2O and MnCl2·5H2O with (NH4)2S in aqueous solution. Atomic absorption spectrometry (AAS) and energy dispersive spectroscopy (EDS) were used to determine the Mn contents of these complex nanorods. The samples were characterized by scanning electron microscopy (SEM-EDS), X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-vis absorption spectra, photoluminescence (PL) and compared with the undoped CdS nanorods. The results showed that nanostructured multiplex compounds with high aspect ratio were obtained via hydrothermal method. The products showed almost totally rod-like morphology with approximately identical diameter about 20 nm and the maximal length up to 200 nm. 相似文献
96.
We analyse the optimized geometric structure and energies of N,N′-diphenyl-N,N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD) neutral molecule in ground and excited states. Ab initio calculations are performed at the Hartree–Fock (HF) or single-excitation (CIS) level with 6-31G basis set using Gaussian 98 program. We got a good qualitative agreement with the results for the neutral molecule in the ground state obtained by density functional theory methods, which were previously reported in the literature. TPD in the ground state has a pronounced twisted geometry, with both central and peripheral dihedral angles of about 40°. On the other hand, the structure of excited state is more planar, as the central dihedral angle becomes smaller. We estimated the reorganization energies associated with the optical transitions, corresponding transition dipole moments, as well as HOMO and LUMO. On the basis of ab initio calculations, we developed a semi-empirical model for the observed absorption and photoluminescence and interpreted the large Stokes shift of about 0.4 eV. 相似文献
97.
98.
Bénédicte Martin Ghislain Blanquet Muriel Lepère 《Journal of Molecular Spectroscopy》2006,236(1):52-57
The CO2-broadening coefficients of 24 P- and R-branch transitions in the ν4 + ν5 band of acetylene were measured at room temperature using a diode-laser spectrometer. These lines with J values up to 26, were located in the spectral range 1270 to 1400 cm−1. The collisional broadening coefficients were retrieved by fitting the experimental profiles to the Voigt, Rautian, and Galatry lineshape models. Two experimental values for the narrowing coefficient were determined from the spectra and compared with the theoretical narrowing coefficient. The calculations of these broadenings were also performed in the frame of a semiclassical formalism involving a simple intermolecular potential with an adjustable parameter. The theoretical results are in good agreement with the experimental results and reproduce well the J dependence of the broadening coefficients. 相似文献
99.
M.M. Yamada 《Journal of Quantitative Spectroscopy & Radiative Transfer》2005,95(2):221-230
The pressure broadening coefficients and their temperature dependences for two submillimeter-wave transitions of ozone, one being monitored with Odin and the other to be monitored with JEM/SMILES and EOS-MLS, have been determined by using a BWO based submillimeter-wave spectrometer. The measurements have also been extended to one of the symmetric isotopic species, 16O18O16O. The isotopic species is observed in natural abundance and as a consequence the temperature dependence is not determined due to weak signal intensity. The pressure broadening parameters are determined with better than 1% accuracy, while the temperature dependence exponents are obtained within 1.5-3% accuracy for the normal species transitions. 相似文献
100.
E. Márquez J.M. González-Leal R. Prieto-Alcón M. Vlcek A. Stronski T. Wagner D. Minkov 《Applied Physics A: Materials Science & Processing》1998,67(3):371-378
40 S40Se20, deposited by thermal evaporation, were obtained in the 400 nm to 2200 nm spectral region. The optical constants of this
amorphous material were computed using an optical characterization method based mainly on the ideas of Minkov and Swanepoel
of utilising the upper and lower envelopes of the spectrum, which allows us to obtain both the real and imaginary parts of
the complex refractive index, and the film thickness. Thickness measurements made by a surface-profiling stylus have been
carried out to cross-check the results obtained by the optical method. The dispersion of the refractive index is discussed
in terms of the single-oscillator Wemple–DiDomenico model. The optical band gap has been determined from absorption coefficient
data by Tauc’s procedure. Finally, the photo-induced and thermally induced changes in the optical properties of a-As40S40Se20 thin films were also studied, using both transmission and reflection spectra.
Received: 11 February 1998/Accepted: 16 February 1998 相似文献