75 research outputs found
Ultrafast quasiparticle relaxation dynamics in normal metals and heavy fermion materials
We present a detailed theoretical study of the ultrafast quasiparticle
relaxation dynamics observed in normal metals and heavy fermion materials with
femtosecond time-resolved optical pump-probe spectroscopy. For normal metals, a
nonthermal electron distribution gives rise to a temperature (T) independent
electron-phonon relaxation time at low temperatures, in contrast to the
T^{-3}-divergent behavior predicted by the two-temperature model. For heavy
fermion compounds, we find that the blocking of electron-phonon scattering for
heavy electrons within the density-of-states peak near the Fermi energy is
crucial to explain the rapid increase of the electron-phonon relaxation time
below the Kondo temperature. We propose the hypothesis that the slower Fermi
velocity compared to the sound velocity provides a natural blocking mechanism
due to energy and momentum conservation laws.Comment: 10 pages, 11 figure
Asymptotic Expansions for Stationary Distributions of Perturbed Semi-Markov Processes
New algorithms for computing of asymptotic expansions for stationary
distributions of nonlinearly perturbed semi-Markov processes are presented. The
algorithms are based on special techniques of sequential phase space reduction,
which can be applied to processes with asymptotically coupled and uncoupled
finite phase spaces.Comment: 83 page
Catalytic method of synthesis of 2,4-diphenylfuran and 2-phenylindole
2,4-Diphenylfuran has been obtained from acetophenone and its mixture with aniline, over K-16 catalyst. It has been established that the reaction proceeds through a stage of dypnone formation. When the aniline-acetophenone mixture is used as the starting material, small amounts of 2-phenylindole are formed. Β© 1992 Plenum Publishing Corporation
Catalytic method of synthesis of 2,4-diphenylfuran and 2-phenylindole
2,4-Diphenylfuran has been obtained from acetophenone and its mixture with aniline, over K-16 catalyst. It has been established that the reaction proceeds through a stage of dypnone formation. When the aniline-acetophenone mixture is used as the starting material, small amounts of 2-phenylindole are formed. Β© 1992 Plenum Publishing Corporation
N-allylation and N-benzylation of 2-phenylindole and its condensation with carbonyl compounds
By allylation and benzylation of 2-phenyl- and 2-phenyl-3-formylindole, N-allyl- and benzyl-substituted indoles have been obtained. By condensation of 2-phenylindole with 2-formylfluorene, and also with 4-aza- or 3-methyl-2-azafluorenone, compounds containing fragments of the indole, fluorene, and azafluorenone systems have been synthesized. In the interaction of 2-phenylindole or indole with formaldehyde and 2,5-dimethylpiperidin-4-one, depending on the temperature, bis(2-phenylindol-3-yl)methane, (2β²,5β²-dimethyl-4β²-oxopiperidino)-(1-indolyl)methane, and bis(indol-3-yl)methane are formed. Β© 1993 Plenum Publishing Corporation
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