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71.
T. Kumita Y. Kamiya M. Babzien I. Ben-Zvi K. Kusche I. V. Pavlishin I. V. Pogorelsky D. P. Siddons V. Yakimenko T. Hirose T. Omori J. Urakawa K. Yokoya D. Cline F. Zhou 《Laser Physics》2006,16(2):267-271
Thomson scattering of high-power laser and electron beams is a good test of electrodynamics in the high-field region. We demonstrated production of high-intensity X-rays in the head-on collision of a CO2 laser and 60-MeV electron beams at Brookhaven National Laboratory, Accelerator Test Facility. The energy of an X-ray photon was limited at 6.5 keV in the linear (lowest order) Thomson scattering, but the nonlinear (higher order) process produces higher energy X-rays. We measured the angular distribution of the high-energy X-rays and confirmed that it agrees with theoretical predictions. 相似文献
72.
The tape stripping technique is an experimental method frequently used for reconstruction of the in-depth distribution of various topically administered substances within the horny layer of human skin, e.g., compounds contained in sunscreens. Titanium dioxide (TiO2) nanoparticles (25–200 nm in diameter) are one such compound. Optical techniques which apply blue light are found to be suitable for reconstruction. However, the presence of particles affects the light propagation within the skin and therefore causes incorrect determination of strip thickness, leading to an improper reconstructed distribution of nanoparticle concentration revealed from the experimental data. This study evaluates the errors emerging from the use of blue (400 nm) and NIR (800 nm) radiation and finds the use of longer wavelength light more advantageous. Particles of different diameters are considered, and it is revealed that the application of small particles (25–60 nm) results in the lowest rate of error. 相似文献
73.
74.
The spatial structure of Bragg angles and the transfer functions of an acousto-optic cell are calculated for the cases of isotropic and anisotropic light diffraction in a uniaxial crystal. Their change with ultrasound frequency is traced. The possibility of image processing by acousto-optic filtration of the spatial spectrum of an image is considered. The results of experimental visualization of the transfer functions of a calcium molybdate crystal cell are presented. 相似文献
75.
V. Yu. Belashov 《Radiophysics and Quantum Electronics》2002,45(5):376-380
We consider generalizations of the earlier results, obtained for one-dimensional equations of the Kadomtsev–Petviashvili (KP) class, to two- and three-dimensional KP-class equations with an arbitrary nonlinearity index with allowance for the higher-order dispersion correction and terms describing dissipation and instability. The asymptotics of soliton and nonsoliton solutions are derived. Constructing phase portraits in the 8-dimensional space based on the results of a qualitative analysis of generalized Korteweg–de Vries (KdV) equations is discussed. 相似文献
76.
A noiselike fine structure of ferromagnetic resonance spectra in magnetic powders was investigated after ultrasonic treatment. Magnetic interactions between particles are proved to have an influence upon the fine structure formation. After decreasing dipole-dipole magnetic interactions in dilute suspension a special order appears in fine-structure spectra, which is generally the same for different systems. 相似文献
77.
de Souza P. A. Garg V. K. Klingelhöfer G. Gellert R. Gütlich P. 《Hyperfine Interactions》2002,139(1-4):705-714
A portable Mössbauer spectrometer, developed for extraterrestrial applications, opens up new industrial applications of MBS. But for industrial applications, an available tool for fast data analysis is also required, and it should be easy to handle. The analysis of Mössbauer spectra and their parameters is a barrier for the popularity of this wide-applicable spectroscopic technique in industry. Based on experience, the analysis of a Mössbauer spectrum is time-consuming and requires the dedication of a specialist. However, the analysis of Mössbauer spectra, from the fitting to the identification of the sample phases, can be faster using by genetic algorithms, fuzzy logic and artificial neural networks. Industrial applications are very specific ones and the data analysis can be performed using these algorithms. In combination with an automatic analysis, the Mössbauer spectrometer can be used as a probe instrument which covers the main industrial needs for an on-line monitoring of its products, processes and case studies. Some of these real industrial applications will be discussed. 相似文献
78.
Critical problems of the present approach of electrolytes for Solid Oxide Fuel Cells (SOFCs) for commercialization are discussed.
Major progress is expected from the development of materials based on the “SEA (Single Element Arrangement)” concept. The
galvanic cell consists in this case basically of a single chemically homogeneous compound, which functions as electrodes at
high and low activity and as electrolyte at intermediate activities of the electroactive component.
In view of the large structural flexibility of the chemical nature of the constitutents, we explored perovskite (ABO3)-type compounds to be used as SEAs for SOFCs. Results of studies on Pr-substituted LSGM and Fe-substituted SrSnO3 perovskite-type oxides are presented. For instance, SrSn1-xFexO3-δ with x=0.1 exhibits p and n-type electronic conduction at the cathode and anode sides of the SOFC, respectively, while oxide
ion conduction prevails at intermediate oxygen partial pressures. The SEA concept is also applicable for other devices in
the field of Ionics. 相似文献
79.
Q. Sun Q. Wang X.G. Gong V. Kumar Y. Kawazoe 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):77-81
We report results of the atomic and electronic structures of Al7C cluster using ab initio molecular dynamics with ultrasoft pseudopotentials and generalized gradient approximation. The lowest energy structure is
found to be the one in which carbon atom occupies an interstitial position in Al7 cluster. The electronic structure shows that the recent observation [Chem. Phys. Lett. 316, 31 (2000)] of magic behavior of Al7C- cluster is due to a large highest occupied and lowest unoccupied molecular orbital (HOMO-LUMO) gap which makes Al7C- chemically inert. These results have further led us to the finding of a new neutral magic cluster Al7N which has the same number of valence electrons as in Al7C- and a large HOMO-LUMO gap of 1.99 eV. Further, calculations have been carried out on (Al7N)2 to study interaction between magic clusters.
Received 28 July 2001 相似文献
80.
An overview of theoretical and experimental studies of the coherent type-B e
+
e-pair production by photons in aligned crystals performed at Nuclear Physics Institute at Tomsk Polytechnic University is given. 相似文献