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71.
Oxygen K-edge x-ray absorption spectra were studied on the electrochromic amorphous thin film a-WO3 in the comparison with crystalline oxides having variable electronic (d0, d1, d2) and atomic structure: monoclinic m-WO3 (insulator - d0), cubic Na0.6WO3 (metal - d1), cubic ReO3 (metal - d1), layered-type hexagonal h-WO3, WO3H2O and with intercalated HxReO3 (metal - d2), HxWO3 oxides having a metal-isulating transition. The changes in the XANES range 10–15 eV above the absorption edge are interpreted
based on the known band-structure calculations. The high-energy features are related to the multiple-scattering processes
(EXAFS) on the nearest atoms. The intensity of the feature at 550–560 eV is attributed for the first time to the value of
the metal-oxygen-metal bond angle.
Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998. 相似文献
72.
Dmitri M. Gitman 《International Journal of Theoretical Physics》1996,35(1):87-99
We describe a class of transformations in a super phase space (we call them D-transformations) which play the role of ordinary canonical transformations in theories with second-class constraints. Namely, in such theories they preserve the form invariance of equations of motion, their quantum analogs are unitary transformations, and the measure of integration in the corresponding Hamiltonian path integral is invariant under these transformations. 相似文献
73.
Abstract— The long lived triplets from all-trans retinal and 11-cis retinal are quenched by a nitroxyl radical, 4-hydroxy-2,2,6,6-tetramethylpiperidinoyl, with essentially identical rate constants. The rates vary with solvent but do not correlate with solvent polarity. The results confirm implications of earlier work with oxygen quenching and are compatible with the view that isomerization occurs in non-relaxed triplets or that the triplet (or triplets) observed spectroscopically decay by way of a single triplet state which has a small electronic energy gap to ground state isomers. 相似文献
74.
Yang Y Nesterenko DV Trump RP Yamaguchi K Bartlett PA Drueckhammer DG 《Journal of chemical information and modeling》2005,45(6):1820-1823
Three new virtual databases have been developed for use with the bond-orientation-based database searching program CAVEAT. These consist of a database of trisubstituted monocyclic hydrocarbons having ethyl, vinyl, and phenyl substituents; a database of unsubstituted bicyclic hydrocarbons; and a database of core structures from established combinatorial synthetic methods having hydrogen, ethyl, vinyl, and phenyl substituents at the readily varied positions. Each collection of molecules was subjected to a batch conformational search, minimization, and conversion to a vector database for use with CAVEAT. 相似文献
75.
Quantum detector properties of the quantum point contact (QPC) are analyzed for an arbitrary electron transparency and coupling strength to the measured system and are shown to be determined by the electron counting statistics. Conditions of the quantum-limited operation of the QPC detector, which prevent information loss through the scattering time and scattering phases, are found for arbitrary coupling. We show that the phase information can be restored and used for the quantum-limited detection by inclusion of the QPC detector in the electronic Mach-Zehnder interferometer. 相似文献
76.
Smalyukh II Lavrentovich OD Kuzmin AN Kachynski AV Prasad PN 《Physical review letters》2005,95(15):157801
Using laser tweezers, we study colloidal interactions of solid microspheres in the nematic bulk caused by elastic distortions around the particles with tangential surface anchoring. The interactions overcome the Brownian motion when the interparticle separation r-->p is less than 3 particle diameters. The particles attract when the angle theta between r-->p and the uniform far-field director n0 is between 0 degrees and approximately 70 degrees and repel when 75 degrees 相似文献
77.
We report a new high-frequency (>10 kHz) ac electrospray that is capable of generating micron-sized electroneutral drops. Unlike its dc counterpart, the drops are not ejected continuously from a sharp Taylor cone but intermittently from a resonating meniscus at the orifice. We attribute the resonant frequency to the capillary-inertia vibration time of the meniscus and the drop ejection to the Maxwell-Wagner electric stress at the drop tip, which is observed to reverse its direction across a crossover frequency. Above this frequency, the oppositely directed Maxwell-Wagner force causes the liquid to recede up the microneedle as an apparent electrowetting effect. 相似文献
78.
79.
Throughout this paper, G is a connected semisimple algebraicgroup defined over an algebraically closed field k of characteristiczero, and g is its Lie algebra. 相似文献
80.
Anomalous absorption of bulk shear sagittal acoustic waves in a layered structure with viscous fluid
It is demonstrated theoretically that the absorptivity of bulk shear sagittal waves by an ultra-thin layer of viscous fluid between two different elastic media has a strong maximum (in some cases as good as 100%) at an optimal layer thickness. This thickness is usually much smaller than the penetration depths and lengths of transverse and longitudinal waves in the fluid. The angular dependencies of the absorptivity are demonstrated to have significant and unusual structure near critical angles of incidence. The effect of non-Newtonian properties and non-uniformities of the fluid layer on the absorptivity is also investigated. In particular, it is shown that the absorption in a thin layer of viscous fluid is much more sensitive to non-zero relaxation time(s) in the fluid layer than the absorption at an isolated solid-fluid interface. 相似文献