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41.
Aleksey M. Shor Elena A. Ivanova-Shor Svetlana S. Laletina Vladimir A. Nasluzov Notker R?sch 《Surface science》2010,604(19-20):1705-1712
We studied the interaction of small Agn clusters (n = 1–4) with paramagnetic defect centers of a dehydroxylated silica surface using an all-electron scalar relativistic density functional method. The surface and adsorption complexes on it were modeled with an accurate quantum mechanics/molecular mechanics (QM/MM) scheme of embedding QM clusters in an elastic polarizable environment, described at the molecular mechanics level (MM). We analyzed two types of frequent point defects as sites for trapping and growing of Ag clusters: a silicon atom with a dangling bond (E′ center), ≡ Si?, and a non-bridging oxygen center (NBO), ≡ Si–O?. The Ag clusters interact with these paramagnetic centers forming strong covalent metal-defect bonds. The high adsorption energy allows one to consider the NBO and E′ sites as traps of single Ag atoms and as centers of cluster growth. We also explored the effect of adsorption on observable electronic properties of the silver clusters and of the defects of the silica surface. 相似文献
42.
The scattering of a well collimated electron beam by a strong standing laser wave of ultrashort duration, giving rise to a great number of scattered photons, is considered. This type of scattering is found to cause an electron beam to divide effectively into two parts. Ultrashort laser pulses are shown to be capable of forming ultrashort electron bunches whose length is governed by the laser beam diameter. 相似文献
43.
E. V. Brakhman G. V. Danilyan A. V. Fedorov I. L. Karpikhin V. A. Krakhotin V. S. Pavlov R. Golub E. I. Korobkina T. Wilpert 《JETP Letters》2004,80(11):675-677
The preliminary result of the P-odd asymmetry of prompt neutron emission in 235U fission induced by polarized cold neutrons is a=(2.7±0.8)×10?5. Only scission neutrons can show such asymmetry, whereas neutrons emitted by excited fragments are the unavoidable background, which suppress the sought asymmetry. The P-odd asymmetry of light fragment emission for 235U is equal to (8.4±0.6)×10?5. Assuming that the last figure defines the parity mixture of the fissile nucleus, then the suppression factor is equal approximately to 3. 相似文献
44.
N. V. Vysotina A. S. Naumov N. N. Rozanov R. L. Sabirov V. E. Semenov V. A. Smirnov T. V. Starchikova S. V. Fedorov S. A. Chizhov V. E. Yashin 《Optics and Spectroscopy》2004,97(3):411-415
The final stage of self-focusing of 500-ps pulses of a neodymium laser in silicate and phosphate glasses and in the nonlinear liquids perfluorooctane, benzene, and toluene is studied theoretically and experimentally. The formation of spatial solitons, which are stable due to the nonlinearity saturation, is demonstrated. It is found that the intensity of the nonlinearity saturation is close to that of the threshold breakdown for glasses and the role of stimulated Raman scattering is significant for liquids. 相似文献
45.
A. N. Vasiliev V. N. Grishin A. M. Davidenko A. A. Derevschikov Yu. A. Matulenko Yu. M. Melnik A. P. Meschanin V. V. Mochalov L. V. Nogach S. B. Nurushev A. F. Prudkoglyad P. A. Semenov L. F. Soloviev V. L. Solovianov V. Yu. Khodyrev K. E. Shestermanov A. E. Yakutin N. S. Borisov V. N. Matafonov A. B. Neganov Yu. A. Plis Yu. A. Usov A. N. Fedorov A. A. Lukhanin 《Physics of Atomic Nuclei》2004,67(8):1487-1494
Results are presented that were obtained by measuring single-spin asymmetry in the inclusive production of neutral pions in the reaction p+p ↑→ π 0+X at x F≈0. A beam of 70-GeV protons was extracted directly from the vacuum chamber of the accelerator by means of a bent single crystal. For transverse momenta in the range 1.0<p T<3.0 GeV/c, the single-spin asymmetry independently measured by two detectors is zero within the errors. This result is in agreement with Fermilab data obtained at 200 GeV, but it is at odds with CERN data measured at 24 GeV. 相似文献
46.
Valla T Fedorov AV Johnson PD Glans PA McGuinness C Smith KE Andrei EY Berger H 《Physical review letters》2004,92(8):086401
High-resolution photoemission has been used to study the electronic structure of the charge-density wave (CDW) and superconducting dichalcogenide, 2H-NbSe2. From the extracted self-energies, important components of the quasiparticle interactions have been identified. In contrast to previously studied TaSe2, the CDW transition does not affect the electronic properties significantly. The electron-phonon coupling is identified as a dominant contribution to the quasiparticle self-energy and is shown to be very anisotropic (k dependent) and much stronger than in TaSe2. 相似文献
47.
P. V. Pavlov I. V. Babushkin N. A. Loiko N. N. Rosanov S. V. Fedorov 《Radiophysics and Quantum Electronics》2004,47(10-11):898-904
We consider spatial dissipative solitons arising in the system of two nonlinear thin films which interact resonantly with light. Symmetric and nonsymmetric solitons and methods of their exciting and switching are studied. 相似文献
48.
Yang HB Pan ZH Sekharan AK Sato T Souma S Takahashi T Jin R Sales BC Mandrus D Fedorov AV Wang Z Ding H 《Physical review letters》2005,95(14):146401
We report a systematic angle-resolved photoemission study on Na(x)CoO2 for a wide range of Na concentrations (0.3 < or = x < or = 0.72). In all the metallic samples at different x, we observed (i) only a single holelike Fermi surface centered around gamma and (ii) its area changes with x according to the Luttinger theorem. We also observed a surface state that exhibits a larger Fermi surface area. The e'(g) band and the associated small Fermi surface pockets near the K points predicted by band calculations are found to sink below the Fermi energy in a manner almost independent of the doping and temperature. 相似文献
49.
A. A. Kotov L. A. Vaishnene V. G. Vovchenko Yu. A. Gavrikov V. V. Polyakov M. G. Tverskoi O. Ya. Fedorov T. Fukahori Yu. A. Chestnov A. V. Shvedchikov A. I. Shchetkovskii 《Bulletin of the Russian Academy of Sciences: Physics》2007,71(6):809-811
The results of measuring total cross sections for proton-induced fission of natPb, 209Bi, 232Th, 233U, 235U, 238U, 237Np, and 239Pu nuclei at proton energies from 200 to 1000 MeV are reported. The measurements were carried out in steps of ≈100 MeV. Complementary fission fragments were detected in coincidence by two parallel-plate avalanche gas counters placed in the beam line on both sides of the thin target close to it. Energy and isotope dependences of the fission cross sections are analyzed. 相似文献
50.
V. Trnovcová P. P. Fedorov M. D. Valkovskii T. Šrámková A. A. Bystrova B. P. Sobolev 《Ionics》1997,3(3-4):313-320
The anisotropy of the ionic conductivity and permittivity of (1) BaR2F8 (R=rare earth element) single crystals with monoclinic BaTm2F8 structure and of (2) (β-YF3 structured) rare earth trifluorides is studied. Single crystals, eutectic composites and ceramics are investigated in a broad
temperature range. In the monoclinic BaR2F8 crystals, a pronounced anisotropy of the ionic conductivity and a slight anisotropy of the permittivity are found. The fastest
ionic transport with the lowest activation energy (0.563 eV) and the highest value of the permittivity are observed along
thea axis. The temperature dependencies of the fluoride ion conductivities of various orthorhombic rare earth trifluorides differ
only slightly from one another. For the bulky single crystals, the conductivity at 500 °C and the conduction activation enthalpy
are equal to 1.1(4)×10−5 S/cm and 0.75(3) eV, respectively. The ionic conductivity is almost isotropic, but the anisotropy of the permittivity is
significant. For the fluorides of both structural types, plausible conduction mechanisms are proposed, networks of most probable
conduction paths are presented and the origin of the observed anisotropy of the ionic conductivity is elucidated.
Paper presented at the 4th Euroconference on Solid State Ionics, Renvyle, Galway, Ireland, Sept. 13–19, 1997 相似文献