126 - 150 of 924
Number of results to display per page
126 Saam, BrianWall relaxation of 3He in spin-exchange cellsThe 3He longitudinal spin-relaxation rate T1-1 is crucial for production of highly polarized 3He by spin-exchange optical pumping. We show that T1-1 is increased by a factor of 2-20 solely by exposure of spin-exchange cells to a few-kG magnetic field. The original T1-1 can be restored by degaussing ...Wall relaxation; Spin-exchange cells; 3He; Longitudinal spin-relaxation; Spin-exchange optical pumping; SEOP; Hyperpolarized 3He; Surface magnetism; Glass cells2001-09
127 Vardeny, Zeev ValentineOptical studies of metallodielectric photonic crystals: bismuth and gallium infiltrated opalsWe have fabricated three-dimensional metallodielectric photonic crystals that consist of bismuth and gallium metals infiltrated into porous synthetic opals that have 300 nm diam silica balls. The specular reflectivity was measured in a broad spectral range from 0.3 to 25 mm using a variety of light ...Metallodielectric photonic crystals; Bismuth infiltrated opals; Gallium infiltrated opals; Bragg; Porous synthetic opals2004
128 Vardeny, Zeev ValentineSpecific heats and lattice dynamics of cuprous halidesThe specific heats Cp(T) of CuCl, CuBr, and Cul were measured by the adiabatic calorimetric technique. The corresponding Debye temperature for each crystal is given and a comparison between the results is drawn. The room-temperature phonon dispersion relations for these cystals are fitted by a nine...Cuprous halides; CuBr; CuCl; CuI1978-10
129 Wu, Yong-ShiNear-horizon Virasoro symmetry and the entropy of de Sitter space in any dimensionDe Sitter spacetime is known to have a cosmological horizon that enjoys thermodynamic-like properties similar to those of a black hole horizon. In this note we show that a universal argument can be given for the entropy of de Sitter spacetime in arbitrary dimensions, by generalizing a recent near ho...1999-05
130 Symko, Orest GeorgeSize considerations in interfacing thermoacoustic coolers with electronicsSmall thermoacoustic coolers heat pumps show much promise for heat management in microcircuits, especially since they can be miniaturized for interfacing with circuits. Usually they are operated in the resonant mode with sound pumping heat; the device dimensions are reduced when the acoustic pump fr...Thermoacoustic coolers; Heat management; Microcircuits; Miniturization2002
131 Vardeny, Zeev ValentineHigh-pressure study of picosecond exciton dynamics in solid C60We have studied the singlet exciton decay by picosecond photoinduced absorption in films of Qo, under pressures up to 62 kbar. The picosecond decay of excitons excited in the absorption tail continues to be dominated by broad distributions of lifetimes at high pressure. These results suggest that th...Picosecond exciton dynamics; Solid C601994-08
132 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
133 Mishchenko, EugeneMesoscopic spin-Hall effect in 2D electron systems with smooth boundariesThe spin-Hall effect in a ballistic 2D electron gas with Rashba-type spin-orbit coupling and smooth edge confinement is studied. We predict that the interplay of semiclassical electron motion and quantum dynamics of spins leads to several distinct features in spin density along the edge that origina...Spin- Hall effect; 2D electron systems2009-05
134 Symko, Orest GeorgeDoes the quasicrystal AlCuFe follow Ohm's law?We present the first measurements of the electrical I-V characteristics of AlCuFe quasicrystalline thin films processed by solid state interdiffusion of magnetron sputtered Al, Cu, and Fe layers. Despite the peculiar electronic properties of quasicrystals, our results show that those samples follow ...AlCuFe; Quasicrystal1994-10
135 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
136 DeTar, CarletonHigh-precision lattice QCD confronts experimentThe recently developed Symanzik-improved staggered-quark discretization allows unquenched lattice-QCD simulations with much smaller (and more realistic) quark masses than previously possible. To test this formalism, we compare experiment with a variety of nonperturbative calculations in QCD draw...Staggered quarks2004-01
137 Mattis, Daniel C.Tricritical point in random-field Ising modelThe numerical investigation of the random-field Ising model by Houghton, Khurana, and Seco1 has revealed a number of interesting features concerning the three-dimensional Ising model in a random external field Bt. Earlier, Aharony2 had already found that even in a mean-field approximation the b...Random external field; Tricritical points; Gaussian distribution1985
138 Vardeny, Zeev Valentine; Nahata, AjayThermal emission from metallic films perforated with subwavelength hole arraysThis report presents an overview of our study on the optical transmission and thermal light emission properties of subwavelength hole arrays fabricated in a square lattice with 4 um periodicity. The structures were fabricated in thin aluminum (Al) films on silicon (Si) substrates using conventional ...2008
139 Gondolo, PaoloCosmic ray positron excess and neutralino dark matterUsing a new instrument, the HEAT Collaboration has confirmed the excess of cosmic ray positrons that they first detected in 1994. We explore the possibility that this excess is due to the annihilation of neutralino dark matter in the galactic halo. We confirm that neutralino annihilation can produ...Neutralinos; Supersymmetric models; Positron flux; Annihilations2002-02
140 Wu, Yong-ShiGround-state degeneracy in the Levin-Wen model for topological phasesWe study the properties of topological phases by calculating the ground-state degeneracy (GSD) of the two-dimensional Levin-Wen (LW) model. Here it is explicitly shown that the GSD depends only on the spatial topology of the system. Then we show that the ground state on a sphere is always nondegener...2012-01-01
141 Lupton, John MarkMechanisms of spin-dependent dark conductivity in films of a soluble fullerene derivative under bipolar injectionWe report room-temperature pulsed electrically detected magnetic resonance measurements of the dark conductivity of films of the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) under bipolar (electron-hole) and unipolar (electron-rich) injection conditions. Directly after mate...2014-01-01
142 Vardeny, Zeev ValentineMechanically stretchable and reversibly deformable liquid metal-based plasmonicsWe demonstrate that liquid metals are attractive materials for active plasmonic devices at terahertz frequencies. Using a liquid metal injected into an elastomeric mold, we measure the static and stretched transmission properties of aperture arrays.2012-01-01
143 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
144 Gerton, JordanImproved localization accuracy in stochastic super-resolution fluorescence microscopy by K-factor image deshadowingLocalization of a single fluorescent particle with sub-diffraction-limit accuracy is a key merit in localization microscopy. Existing methods such as photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM) achieve localization accuracies of single emitt...2014-01-01
145 Gondolo, PaoloLight dark matter in leptophobic Z' modelsRecent experimental results in direct dark matter detection may be interpreted in terms of a dark matter particle of mass around 10 GeV=c2. We show that the required scenario can be realized with a new dark matter particle charged under an extra Abelian gauge boson Z0 that couples to quarks but not ...2012-01-01
146 Lupton, John MarkExciton storage in CdSe/CdS tetrapod semiconductor nanocrystals: electric field effects on exciton and multiexciton statesCdSe/CdS nanocrystal tetrapods are interesting building blocks for excitonic circuits, where the flow of excitation energy is gated by an external stimulus. The physical morphology of the nanoparticle, along with the electronic structure, which favors electron delocalization between the two semicond...2012-01-01
147 DeTar, CarletonTensor component of the two-nucleon interaction in the quark-bag modelA previously developed method for computing the interaction energy of the two-nucleon system at short distances in the static MIT bag model of confined quarks is extended to all isospin and spin channels available to the two-nucleon interaction. The present study is restricted to spherical geometri...Bag models; Quark bag; Nucleons; Deformation energy1979-03
148 Ailion, David CharlesProtein hydration changes in the formation of the nicotinamide adenine dinucleotide complexes of glyceraldehyde 3-phosphate dehydrogenase of yeast. II. The spin lattice relaxation of solvent water protonsThe glyceraldehyde 3-phosphate dehydrogenase of yeast is known to undergo a particle volume contraction and the commensurate loss of a hydration component when it forms a complex with NAD. We have inquired whether the water movement in the conformational transition can be monitored by measurements ...Protein hydration; Nicotinamide adenine dinucleotide complexes; Glyceraldehyde 3 phosphate dehydrogenase; Solvent water protons1973
149 DeTar, CarletonQCD thermodynamics with Wilson quarks at large KWe extend our study of the high temperature transition with two flavors of Wilson quarks on 123 x 6 lattices to K = 0.19. We also perform spectrum calculations on 123 x 24 lattices at K = 0.19 to find the physical lattice spacing and quark mass. At this value of K the transition is remarkable in tha...Wilson quarks; Polyakov loop; Phase transitions1994-09
150 DeTar, CarletonQCD equation of state with 2+1 flavors of improved staggered quarksWe report results for the interaction measure, pressure, and energy density for nonzero-temperature QCD with 2 + 1 flavors of improved staggered quarks. In our simulations, we use a Symanzik improved gauge action and the Asqtad O(a2) improved staggered quark action for lattices with temporal extent ...Staggered quarks; Quark-gluon plasma2007-05
126 - 150 of 924