UScholar Works
 
Filters: Department: "Physics" Collection: "ir_uspace"
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CreatorTitleDescriptionSubjectDate
1 Ailion, David Charles109Ag NMR investigation of atomic motions in the incommensurate and paraelectric phases of proustite (Ag3AsS3)109Ag NMR line shape, T1 , Hahn spin echo, and Carr-Purcell-Meiboom-Gill ~CPMG! spin-echo measurements were performed in proustite (Ag3AsS3) between 420 and 47 K in order to understand the role of atomic motions in phase transitions in a system containing an incommensurate phase. These measurements ...NMR; Atomic motion; Proustitie; Phase transitions; Line shape2000
2 Ailion, David Charles14N study of the role of N-D---O bonds in the deuteron glass transition14N spin-lattice relaxation-time measurements in Rb0.28(ND4)0.72D2PO4 provide direct evidence for the fast exchange averaging of the "long" and "short" N-D---O hydrogen bonds between the ND4 group and the four surrounding PO4 groups. This exchange and the associated distortion of the ND4 tetrahedron...NMR; Hydrogen bonds; Spin-lattice; Relaxation-time; Deuteron glass1999
3 Ailion, David Charles31P NMR spin-lattice relaxation: structural glass dynamics in Rb1-x(ND4)xD2PO4We performed 3 1P NMR measurements of the temperature-dependent spin-lattice relaxation time in several mixed single crystals of Rbi_x(ND4 ) xD2P04 [DRADP] having different ammonium concentration x (x =0.22, 0.44, 0.78) as well as in three pure single crystals (ND4)D2P04 [DADP], (NH4)H2P04 [ADP], an...NMR; Spin-lattice; Relaxation; Crystals; Glass; Spin-glass1993
4 Ailion, David Charles; Blinc, Robert35Cl spin-lattice relaxation in incommensurate bis(4-chlorophenyl)sulfoneThe 35C1 nuclear-quadrupole-resonance (NQR) spin-lattice relaxation rate in incommensurate bis(4- chlorophenyl)sulfone (BCPS) is determined by Raman processes below 60 K and by direct one-phonon processes above 60 K. The variation of the 35C1 spin-lattice relaxation rate over the incommensurate NQR...35Cl; Incommensurate bis(4-chlorophenyl)sulfone; Raman processes; NQR; Incommensurate systems1995-01
5 Saam, Brian3He spin exchange cells for magnetic resonance imagingWe present a protocol for the consistent fabrication of glass cells to provide hyperpolarized (HP) 3He for pulmonary magnetic resonance imaging. The method for producing HP 3He is spin-exchange optical pumping. The valved cells must hold of order 1 atm.L of gas at up to 15 atm pressure. Because char...3He; Spin exchange cells; Hyperpolarized 3He; Pulmonary magnetic resonance imaging; Spin-exchange optical pumping; SEOP; Glass cells2002
6 Ailion, David Charles79Br nuclear-quadrupole-resonance lineshape and Raman-induced spin-lattice relaxation in the incommensurate phase of β- ThBr4We performed 7 9Br nuclear-quadrupole-resonance (NQR) line-shape and spin-lattice relaxation time measurements in the incommensurate (D system j8-ThBr4 over the temperature range 293-2.5 K. In addition, we extended the theory of the effects of Raman processes on amplitudon and phason spin-lattice re...Spin-lattice; NQR; Raman process; Line shape; Phason gap; Incommensurate systems1989
7 Ailion, David Charles93Nb NMR in the imcommensurate and quasi-commensurate phases of barium sodium niobateNMR spectra have been measured for the quadrupole perturbed 1/2 -1/2 transition of 9 3Nb in barium sodium niobate (BSN) between 300 and 650 K. The spectra are inhomogeneously broadened in the incommensurate (/) phase between T7 = 580 K and r c = 540 K as well as in the quasicommensurate (QC) phase ...NMR; Spectra; Barium sodium niobate; Line shapes1994
8 Mattis, Daniel C.A contribution to the many-fermion problemIn this work we reexamine the many-fermion problem in arbitrary dimensions. It is shown that in two dimensions or higher, the Hamiltonian of interacting fermions can be separated into individual nonintersecting sectors labeled by the wave-vector q. Within each sector the Hamiltonian maps onto a gene...2012-01-01
9 Gondolo, PaoloAberration features in directional dark matter detectionThe motion of the Earth around the Sun causes an annual change in the mag-nitude and direction of the arrival velocity of dark matter particles on Earth, in a way analogous to aberration of stellar light. In directional detectors, aberration of weakly interacting massive particles (WIMPs) modulates ...2012-01-01
10 Wu, Yong-ShiAbsence of (1,0) supersymmetry anomaly in world-sheet gauge theories: a purely cohomological proofA purely cohomological proof is given for the absence of the (1,0) supersymmetry anomaly in gauge theories on a world sheet. In particular, it is shown that generalized cohomological approaches to anomalies in supersymmetric gauge theory, either formulated in whole superconnection space or only in t...World sheet; String theory; Superfields; Superspace1989-01
11 Symko, Orest GeorgeAbsorption at radio frequencies in superconducting Y1Ba2Cu3OyThe large magnetic-field-dependent ac absorption in superconducting Y1Ba2Cu3Oy ceramics and powders decreases slowly with increasing frequency in the range 2-16 MHz. The magnetic-field-dependent ac absorption is observed below Tc in superconducting Y1Ba2Cu3Oy ceramics, powders and twinned crystals ...Copper-octahedral oxygen perovskites; Superconducting Y1Ba 2Cu3Oy; ac absorption1989
12 Vardeny, Zeev ValentineAbsorption studies of charged excitations in α-sexithiopheneWe present photoexcitation studies of vacuum deposited neutral films of α,ω-substituted sexithiophene (α-6T) using photoinduced absorption (PA) and PAdetected magnetic resonance spectroscopy (PADMR). We find evidence for photoinduced polarons having spin 1/2, with two absorption bands at 0.80...alpha- sexithiophene; Charged excitations; Photoexcitation; Photoinduced absorption1996
13 Vardeny, Zeev ValentineAbsorption-detected magnetic-resonance studies of photoexcitations in conjugated-polymer/C60 compositesPhotoexcitations in poly[2-methoxy-5-(2'-ethyl-hexyloxy -p-phenylene vinylene] (MEH-PPV) and composites of MEH-PPV and C60 (MEH-PPV/C60) were studied by photoinduced absorption and absorptiondetected magnetic-resonance spectroscopies. We report direct evidence that the prominent triplet photoexci...Photoexcitations; Conjugated-polymer/C60 composites; Triplet photoexcitations1996-02
14 Mattis, Daniel C.Accuracy of bosonization for localized interactionsBosonization is commonly used to calculate the ground-state energy and the dynamics of simple model nonmagnetic impurities in metals. We analyze the accuracy of this procedure in the calculation of the ground-state energy of a simple, solvable, model.Fermions; Electrons; Magnetic2000
15 Symko, Orest GeorgeAcoustic approach to thermal management: miniature thermoacoustic enginesAn acoustic approach to thermal management in electronics can be efficient and it can be directly interfaced with electronic devices. It is based on two types of thermoacoustic heat engines, which are being developed for microcircuit applications. One type of device, the prime mover, converts heat t...Thermoacoustic engines; Thermal management2006
16 Symko, Orest GeorgeAdiabatic compressional cooling of He3By adiabatic compression of a two-phase mixture of liquid and solid He3, temperatures below 2.5 mK have been obtained. These are in the range expected for nuclear ordering in solid He3.He3; Adiabatic compressional cooling1969-03
17 Rogachev, AndreyAdmittance spectroscopy study of polymer diodes in small magnetic fieldsWe performed a systematic study of bipolar and unipolar organic diodes based on the p-conjugated polymer, 2-methoxy-5-(20-ethylhexyloxy) (MEH-PPV), using electronic and magneto-transport measurements with magnetic field in the range 0-180mT and admittance spectroscopy in the frequency range 1 Hz<f<1...2012-01-01
18 Williams, Clayton C.Advances in experimental technique for quantitative two dimensional dopant profiling by scanning capacitance microscopySeveral advances have been made toward the achievement of quantitative two-dimensional dopant and carrier profiling. To improve the dielectric and charge properties of the oxide-silicon interface, a method of low temperature heat treatment has been developed which produces an insulating layer with c...Doping; Scanning capacitance microscope; SCM1999
19 Gondolo, PaoloAGAPE, a microlensing search in the direction of M31: status reportThe M31 galaxy in Andromeda is the nearest large galaxy after the Small and Large Magellanic Clouds. It is a giant galaxy, roughly 2 times as large as our Milky Way, and has its own halo. As pointed by some of us [1, 2] and independantly by A. Crotts [3], M31 provides a rich field of stars to searc...AGAPE; Andromeda Gravitational Amplification Pixel Experiment; Microlensing; MACHO; Massive compact halo objects1995
20 Gondolo, PaoloAGAPE: a search for dark matter in M31 by microlensing effects on unresolved starsM 31 is a very tempting target for a microlensing search of compact objects in galactic haloes. It is the nearest large galaxy, it probably has its own dark halo, and its tilted position with respect to the line of sight provides an unmistakable signature of microlensing. However most stars of M 31...M31; AGAPE; Pixel method; Galaxy; Halo; Cosmology; Gravitational lensing1997
21 Gondolo, PaoloAGAPE: andromeda gravitational amplification pixel experimentThe aim of the AGAPE (Andromeda Gravitational Ampli_x000C_cation Pixel Experiment), experiment which has been _x000C_rst proposed in June 1992 is to examine the distribution of massive astrophysical compact halo objects ((MACHO's) which possibly are in the galactic haloes and which could account for...AGAPE; Andromeda Gravitational Amplification Pixel Experiment; Microlensing; MACHO; Massive compact halo objects1997
22 Gondolo, PaoloAGAPEROS: searching for microlensing in the LMC with the pixel method. I. Data treatment and pixel light curves productionRecent surveys monitoring millions of light curves of resolved stars in the LMC have discovered several microlensing events. Unresolved stars could however signi _x000C_cantly contribute to the microlensing rate towards the LMC. Monitoring pixels, as opposed to individual stars, should be able to ...Data analysis techniques; Halo; Galaxies; Gravitational lensing; Pixel method; Large Magellanic Cloud; LMC1999
23 Gondolo, PaoloAgapeZ1: a large amplification microlensing event or an odd variable star towards the inner bulge of M31AgapeZ1 is the brightest and the shortest duration microlensing candidate event found to date in the Agape experiment. It occurred only 4200 from the centre of M31 at RA = 0h42m41:47s and Dec = 41°16'39.1" (J2000). Our photometry shows that the half intensity duration of the event is 5.3 days and ...AgapeZ1; Galaxy; Halo; Cosmology; Gravitational lensing; M31; Pixel method1999
24 Lupton, John MarkAir-induced fluorescence bursts from single semiconductor nanocrystalsWe observe a dramatic enhancement of the fluorescence intensity from single core/shell CdSe/ZnS nanocrystals upon sudden exposure to air from an evacuated surrounding. Both the number of particles contributing to emission increases as well as the average emission intensity from a single particle, le...CdSe; ZnS; Air-induced; Fluorescence bursts2004
25 Wu, Yong-ShiAlgebraic and geometric aspects of generalized quantum dynamicsWe briefly discuss some algebraic and geometric aspects of the generalized Poisson bracket and noncommutative phase space for generalized quantum dynamics, which are analogous to properties of the classical Poisson bracket and ordinary symplectic structure.Quantum dynamics; Jacobi identity1994-06
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