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41.
D. R. Tilley 《Zeitschrift für Physik A Hadrons and Nuclei》1970,238(5):399-403
We show that the kernel of the integral equation for the time dependent pair potential can be expressed in terms of a retarded classical normal state correlation function, as conjectured by Bergmann. The proof makes the same assumptions as the corresponding proof for the time independent equation. 相似文献
42.
Tilley RD Warner JH Yamamoto K Matsui I Fujimori H 《Chemical communications (Cambridge, England)》2005,(14):1833-1835
Silicon nanocrystals with a uniform size distribution were synthesized in inverse micelles using powerful hydride reducing agents. The silicon nanocrystals surfaces were then stabilized with 1-heptene to produce particles with strong blue photoluminescence. 相似文献
43.
The phases in samples of gross composition PbxWO3 (0.01 ? x ? 0.28) heated at temperatures between 973 and 1373°K have been investigated. At all temperatures a nonstoichiometric tetragonal tungsten bronze phase forms for compositions x > 0.18. At temperatures up to 1273°K a series of orthorhombic intergrowth bronzes also forms, but these appear to be unstable at higher temperatures and were not found in the preparations made at 1373°K. Aspects of the crystal chemistry of these latter materials are discussed, including structure, crystal habit, valence of the Pb atoms in these phases, and the relation of the phases found here to other related intergrowth bronze phases. 相似文献
44.
D. R. Tilley 《Zeitschrift für Physik A Hadrons and Nuclei》1972,254(1):71-80
We give a general formulation for the problem of scattering of light off the surface of a superconductor with the creation of two quasiparticles. The cross-section is evaluated at all temperatures for a pure superconductor; at zero temperature the result agrees with earlier calculations by Abrikosov and Falkovskii and by Tong and Maradudin. At zero temperature there is no scattering with a frequency shift ω of less than 2Δ; as the temperature increases the scattering for ω<2 Δ increases progressively because of the increasing number of thermally excited quasiparticles. 相似文献
45.
R.O. Nelson J.R. Williams D.R. Tilley D.G. Rickel N.R. Roberson S. Maripuu C.P. Cameron R.D. Ledford 《Nuclear Physics A》1976,261(3):427-438
The mean lifetimes of levels in 55Co below 5.2 MeV have been investigated with the Doppler-shift attenuation method and the 54Fe(3He, d)55Co reaction at 12 MeV. Scattered particles were detected in two E-ΔE telescopes at ±55° with respect to the beam axis, in coincidence with γ-rays observed at 90° and 130° in a 50 cm3 Ge(Li) detector. Mean lifetimes are reported for the following levels (energy in keV, lifetime in fs): 2166 (139±18), 2566 (680±200), 2923 (>245), 2939 (190±65), 3303 (99±22), 3323 (54±15), 3642 (680?300+400), 3943 (>170), 4164 (54±15), 4180 (<16), 4722 (<33), 4749 (<70) and 5174 (<40). The experimental results are compared with a detailed shell-model calculation. 相似文献
46.
Crystals of tin dioxide, SnO2, have been grown pure or doped with a few percent of antimony using vapor growth methods in order to investigate the microstructures of reduced and oxidized SnO2. They were examined by X-ray diffraction and by optical and electron microscopy. SnO2 crystals were found to contain few faults, but the antimony-doped crystals were extensively twinned in some regions. Reduction of SnO2 crystals to yield CS phases was unsuccessful. These results are discussed in terms of the known crystal chemistry of the oxides involved. 相似文献
47.
R.J.D. Tilley 《Journal of solid state chemistry》1982,41(3):233-243
The rhombohedral phase which occurs at about 20 mole% BaO in the Bi2O3BaO system has been studied by electron microscopy. While some material seems identical to that found by X-ray diffraction, many crystals show the existence of a superlattice on the electron diffraction patterns. This superlattice is believed to arise as a result of ordering of the Bi and Ba atoms in the structure. Electron micrographs suggest that the ordered regions are small and can be regarded as microdomains within the parent crystal matrix. 相似文献
48.
E. Iguchi K. Ogino H. Sawatari R.J.D. Tilley 《Journal of Physics and Chemistry of Solids》1981,42(9):813-819
Dielectric constants and a.c. resistivities of rutile (TiO2) doped with gallia (Ga2O3) have been measured as a function of frequency in the range 30–60 kHz at 20°C. The specimens were prepared by heating rutile single crystals on Ga2O3 pellets, at 1300°C, in air for various times. The dielectric constants depend on the frequency of measurement. In the c axis, the dielectric constant at low frequencies (30–100 Hz) increases as the sample heating time is extended to 1 week, but it decreases rapidly when the heating time is prolonged over 1 week. However, in the a axis, the dielectric constant does not change from the value of the starting material, being independent of the heating time. Besides dielectric measurements, the defect structures were determined using transmission electron microscopy, which showed that low concentrations of planar faults on {120} planes occur. The changes in dielectric constant are interpreted as being due to space change effects associated with Ga3+ ions located in the tunnels which lie parallel to the rutile c axis. Calculations are also included which show why other defects in the crystals have no effect on the value of the dielectric constant compared to pure rutile. 相似文献
49.
Three‐Dimensional Branched and Faceted Gold–Ruthenium Nanoparticles: Using Nanostructure to Improve Stability in Oxygen Evolution Electrocatalysis 下载免费PDF全文
Dr. Lucy Gloag Dr. Tania M. Benedetti Dr. Soshan Cheong Dr. Yibing Li Dr. Xuan‐Hao Chan Prof. Lise‐Marie Lacroix Prof. Shery L. Y. Chang Dr. Raul Arenal Dr. Ileana Florea Dr. Hector Barron Dr. Amanda S. Barnard Dr. Anna M. Henning Prof. Chuan Zhao Prof. Wolfgang Schuhmann Prof. J. Justin Gooding Prof. Richard D. Tilley 《Angewandte Chemie (International ed. in English)》2018,57(32):10241-10245
Achieving stability with highly active Ru nanoparticles for electrocatalysis is a major challenge for the oxygen evolution reaction. As improved stability of Ru catalysts has been shown for bulk surfaces with low‐index facets, there is an opportunity to incorporate these stable facets into Ru nanoparticles. Now, a new solution synthesis is presented in which hexagonal close‐packed structured Ru is grown on Au to form nanoparticles with 3D branches. Exposing low‐index facets on these 3D branches creates stable reaction kinetics to achieve high activity and the highest stability observed for Ru nanoparticle oxygen evolution reaction catalysts. These design principles provide a synthetic strategy to achieve stable and active electrocatalysts. 相似文献
50.
In this paper, we describe the synthesis and growth mechanism of highly monodispersed platinum nanocubes. The platinum nanocubes are synthesized by the decomposition of a platinum precursor in a hydrogen atmosphere. The morphology and size distribution of the platinum particles formed has been studied with HRTEM. By controlling the concentration of the platinum precursor, we demonstrate that at low concentration, it is possible to grow polydispersed nanocubes with {1,0,0} facets. Increasing the concentration of the precursor changes the growth mechanism, resulting in the formation of highly monodispersed platinum nanocubes. Highly monodispersed platinum nanocubes are formed in a two-step growth mechanism with initial growth of the {1,1,1} facets followed by secondary growth filling the {1,0,0} facets. The particle monodispersity facilitates the formation of long-range arrays of nanocubes. 相似文献