201 - 225 of 924
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CreatorTitleDescriptionSubjectDate
201 Lupton, John MarkEnergetic disorder limits energy transfer in semiconductor nanocrystal-DNA-dye conjugatesWe demonstrate the influence of spectral linewidths of individual donor-acceptor couples on energy transfer efficiency in semiconductor nanocrystal-DNA-organic dye conjugates. Temperature-dependent single molecule and ensemble spectroscopy data are analyzed using the Förster theory within the mac...2009
202 Symko, Orest GeorgeEnergy conversion using thermoacoustic devicesThermoacoustic engines offer the possibility for simple and efficient energy convmiondevices. They can be prime movers where heat produces sound or heat pumps and refrigerators where sound pump heat. An important element in such engines is the secondary thermodynamic medium, the stack which provides...Thermoacoustic devices; Thermoacoustics1999
203 Sokolsky, PierreEnergy estimation of UHE cosmic rays using the atmospheric fluorescence techniqueWe use the CORSIKA air shower simulation program to review the method for assigning energies to ultra-high energy (UHE) cosmic rays viewed with the air fluorescence technique. This technique uses the atmosphere as a calorimeter, and we determine the corrections that must be made to the calorimetric ...Fluorescence; Energy estimation; Ultra-high energy cosmic rays2000-08
204 Rogachev, AndreyEnhancing superconductivity: magnetic impurities and their quenching by magnetic fieldsMagnetic fields and magnetic impurities are each known to suppress superconductivity. However, as the field quenches (i.e. polarizes) the impurities, rich consequences, including field-enhanced superconductivity, can emerge when both effects are present. For the case of superconducting wires and th...Thermal phase slippage; Coulomb blockade2006-09-01
205 DeTar, CarletonEquation of state and QCD transition at finite temperatureWe calculate the equation of state in 2 + 1 flavor QCD at finite temperature with physical strange quark mass and almost physical light quark masses using lattices with temporal extent Nr = 8. Calculations have been performed with two different improved staggered fermion actions, the asqtad and p4 a...Deconfinement; Chiral symmetry; Staggered fermions; Phase transitions; Polyakov loop2009-07
206 DeTar, CarletonEquation of state for two flavor QCD at Nt=6We calculate the two flavor equation of state for QCD on lattices with lattice spacing a=(6T)21 and find that cutoff effects are substantially reduced compared to an earlier study using a=(4T)21. However, it is likely that significant cutoff effects remain. We fit the lattice data to expected forms ...Phase transitions; Quark-gluon plasma; Chiral symmetry1997-06
207 DeTar, CarletonEquation of state for two flavor QCD at Nt=6We calculate the two flavor equation of state for QCD on lattices with lattice spacing a=(6T)21 and find that cutoff effects are substantially reduced compared to an earlier study using a=(4T)21. However, it is likely that significant cutoff effects remain. We fit the lattice data to expected forms ...Phase transitions; Quark-gluon plasma; Dynamical quarks1997-06
208 Mishchenko, EugeneEquilibrium currents in chiral systems with nonzero Chern numberWe describe a simple quantum-mechanical approach to calculating equilibrium particle current along the edge of a system with nontrivial band spectrum topology. The approach does not require any a priori knowledge of the band topology and, as a matter of fact, treats topological and nontopological co...2014-01-01
209 Gondolo, PaoloEvidence for "sterile neutrino" dark matter?I show that it may be possible to explain the present evidence for a gamma-ray emission from the galactic halo as due to halo WIMP annihilations. Not only the intensity and spatial pattern of the halo emission can be matched but also the relic density of the candidate WIMP can be in the cosmologica...Sterile neutrino; WIMP; Weakly interacting massive particles; Annihilations; Z boson; Higgs sector1998
210 Sokolsky, PierreEvidence for 10^18-eV neutral particles from the direction of Cygnus X-3Analysis of the cumulative Fly's Eye data reveals an excess of air showers from the direction of Cygnus X-3 at energies above 0.5 x 10^18 eV. No point source has previously been identified at such high energies. The probability of this excess arising as a chance clustering of isotropic cosmic rays i...Cygnus X-3; Extensive air showers; Neutral particles1989-01
211 Sokolsky, Pierre; Cassiday, George L.Evidence for a high-energy cosmic-ray spectrum cutoffWe report a measurement of the ultrahigh-energy cosmic-ray spectrum using an atmospheric fluorescence technique for extensive-air-shower detection. The differential spectrum between 0.1 and 10 EeV (1 EeV = 10^18 eV) is well fitted by a power law with slope 2.94 ±0.02. Above 10 EeV evidence is prese...Energy spectrum; Extensive air showers; Spectral cutoff1985-04
212 Vardeny, Zeev Valentine; Raikh, Mikhail E.Evidence for braggoriton excitations in opal photonic crystals infiltrated with highly polarizable dyesWe studied angle-dependent reflectivity spectra of opal photonic crystals infiltrated with cyanine dye aggregates, which are highly polarizable media with very large Rabi frequency. We show that, at resonance condition between the exciton-polariton of the dye aggregate and the Bragg gap, the Bragg s...Braggoriton excitations; Opal photonic crystals; Cyanine dye aggregates; Bragg; Photonic band-gap; PBG; Polarizable dyes2002
213 Kieda, David B.Evidence for changing of cosmic ray composition between 10(17) and 10(18) eV from multicomponent measurementsThe average mass composition of cosmic rays with primary energies between 1017 and 1018 eV has been studied using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum and the ...Cosmic rays; Particle energy; Muon array2000
214 Sokolsky, PierreEvidence for changing of cosmic ray composition between 10^17 and 10^18 eV from multicomponent measurementsThe average mass composition of cosmic rays with primary energies between 1017 and 1018 eV has been studied using a hybrid detector consisting of the High Resolution Fly's Eye (HiRes) prototype and the MIA muon array. Measurements have been made of the change in the depth of shower maximum and the...Extensive air showers; Fluorescence; Energy spectrum; Muon density; Cherenkov light2000-05
215 Sokolsky, PierreEvidence for correlated changes in the spectrum and composition of cosmic rays at extremely high energiesThe Utah Fly's Eye detector has revealed a change in the cosmic ray composition which is correlated with structure in the all-particle energy spectrum. The data can be fitted by a simple model of a steep power law spectrum of heavy nuclei which is overtaken at high energies by a flatter spectrum of ...Energy spectrum; Extensive air showers1993-11
216 Kieda, David B.; Gaisser, Thomas K.; Sokolsky, PierreEvidence for correlated changes in the spectrum and composition of cosmic rays at extremely high energiesThe Utah Fly's Eye detector has revealed a change in the cosmic ray composition which is correlated with structure in the all-particle energy spectrum. The data can be fitted by a simple model of a steep power law spectrum of heavy nuclei which is overtaken at high energies by a flatter spectrum o...Ultrahigh energy cosmic rays; Fly's Eye; Cosmic ray composition; Cosmic ray spectrum1993-11
217 Ailion, David CharlesEvidence for elastic disorder in the elastically ordered phase of KCNWe have obtained evidence from 1 3C NMR measurements that the CN~ ion in the elastically ordered phase of KCN is misoriented slightly with respect to the orthorhombic b axis. This misorientation varies randomly over the lattice, averaging to zero on a macroscopic scale. The misorientations are mani...Potassium cyanide; Anisotropy; Orthorhombic crystal; NMR; Nuclear magnetic resonance1981
218 Vardeny, Zeev ValentineEvidence for excimer photoexcitations in an ordered ?-conjugated polymer filmWe report pressure-dependent transient picosecond and continuous-wave photomodulation studies of disordered and ordered films of 2-methoxy-5-(2-ethylhexyloxy) poly(para-phenylenevinylene). Photoinduced absorption (PA) bands in the disordered film exhibit very weak pressure dependence and are assign...2011
219 Williams, Clayton C.Evidence for internal electric fields in two variant ordered GaInP obtained by scanning capacitance microscopySingle and two variant ordered GaInP samples are studied in cross section with the scanning capacitance microscope. Our study shows significant differences in the electronic properties of single and two variant GaInP. In unintentionally doped, ordered two variant samples, both n and p-type like do...GaInP2; Atomic ordering; Internal electric fields; Scanning capacitance microscope1996
220 Lupton, John MarkEvidence for temperature-independent triplet diffusion in a ladder-type conjugated polymerWe study the temperature dependence of triplet formation and decay by considering the phosphorescence dynamics in a prototypical conjugated polymer matrix. The dynamics of triplet formation as a function of temperature are unraveled by applying an electric field during optical singlet generation a...Triplet diffusion; Triplet excitons; Ladder-type conjugated polymers; Temperature dependence2006-12
221 Williams, Clayton C.Evidence of internal electric fields in GaInP2 by scanning capacitance and near-field scanning optical microscopyGaInP2 is studied in cross section with the scanning capacitance and near-field scanning optical microscope. Our study shows significant differences in the electronic and optical properties between ordered single- and two-variant GaInP2. In single-variant samples, spatially uniform capacitance signa...Atomic ordering; transmission electron diffraction; near-field scanning optical microscope1997
222 Williams, Clayton C.Evidence of internal fields in two-variant ordered GaInP2 by near-field scanning optical microscopyGaInP2 is studied in cross section with the scanning capacitance and near-field scanning optical microscope. Our study shows significant differences in the electronic and optical properties between ordered single- and two-variant GaInP2. In single-variant samples, spatially uniform capacitance signa...Photoluminescence; GaInP2; Microscopy; Electrical fields1997
223 Vardeny, Zeev ValentineEvolution of excitons and polarons in polythiophene from femtoseconds to millisecondsWe have studied the photoexcitation dynamics in electrochemically polymerized polythiophene thin films using transient photomodulation spectroscopy measured from 100 fs to 20 ms in the spectral range from 0.25 to 2.2 eV, and by the novel technique of absorption-detected magnetic resonance (ADMR). ...Femtoseconds; Milliseconds; Photoexcitation dynamics1992-07
224 Mattis, Daniel C.Exact solution of a many-fermion system and its associated boson fieldLuttinger's exactly soluble model of a one-dimensional many-fermion system is discussed. We show that he did not solve his model properly because of the paradoxical fact that the density operator commutators [p(p), p(-p')], which always vanish for any finite number of particles, no longer vanish in ...Many-electron problem; Fermi surface; Boson field; Dirac sea1965
225 Mattis, Daniel C.Exact wave functions in superconductivityThe ground-state wave function and some of the excited states of the BCS reduced Hamiltonian are found. In the limit of large volume, the boundary and continuity conditions on the exact wave function lead directly to the equations which Bardeen, Cooper, and Schrieffer found by a variational techniqu...Ground states1961
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