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| Creator | Title | Description | Subject | Date | ||
|---|---|---|---|---|---|---|
| 1 |
 | Saam, Brian | 3He spin exchange cells for magnetic resonance imaging | We 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 cells | 2002 |
| 2 |
 | Lupton, John Mark | Bright electroluminescence from a conjugated dendrimer | Photoluminescence and electroluminescence (EL) from a conjugated dendrimer consisting of three distyrylbenzene units linked by a central nitrogen atom as core and meta-linked biphenyl units as dendrons were investigated. The conjugated dendrimer emits green light and shows photoluminescence quantum ... | Conjugated dendrimer | 2002 |
| 3 |
 | Ailion, David Charles | Dynamics of the pinned modulation wave in incommensurate bis (4-chlorophenyl) sulfone (BCPS) | We show that both the anomalously huge resonance-frequency dependence of the 3 5Cl nuclear quadrupole resonance (NQR) spin-lattice relaxation time in BCPS, reported here for the first time, and its anomalous temperature dependence can be explained by large-scale fluctuations of the pinned modulation... | NQR; Spin-lattice; Relaxation-time; Pinned modulation wave | 2002 |
| 4 |
 | Vardeny, Zeev Valentine; Raikh, Mikhail E. | Evidence for braggoriton excitations in opal photonic crystals infiltrated with highly polarizable dyes | We 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 dyes | 2002 |
| 5 |
 | Vardeny, Zeev Valentine; Raikh, Mikhail E. | Excitations in opal photonic crystals infiltrated with polarizable media | Photonic crystals (PC) are a class of artificial structures with a periodic dielectric function. PCs can be a laboratory for testing fundamental processes involving interactions of radiation with matter in novel conditions. We have studied the optical properties of opal PCs that are infiltrated with... | Opal photonic crystals; Polarizable media; Bragg gap; Polaritonic gap; Photonic stop band | 2002 |
| 6 |
 | Lupton, John Mark | Exciton confinement in organic dendrimer quantum wells for opto-electronic applications | Organic dendrimers are a fascinating new class of materials for opto-electronic applications. We present coupled electronic oscillator calculations on novel nanoscale conjugated dendrimers for use in organic light-emitting diodes. Strong confinement of excitations at the center of the dendrimers is ... | Exciton confinement; Opto-electronic applications; Coupled electronic oscillator | 2002 |
| 7 |
 | Lupton, John Mark | Frequency up-conversion as a temperature probe of organic opto-electronic devices | Frequency up-conversion is demonstrated in a polyfluorene-based conjugated polymer. Up-converted emission is observed upon excitation to the red of the 0-0 luminescence band. The emission intensity depends strongly on temperature and provides an accurate probe of the operating temperature of organic... | Frequency up-conversion; Organic opto-electronic devices | 2002 |
| 8 |
 | Sokolsky, Pierre | High Resolution Fly's Eye - status and preliminary results on cosmic ray composition above 10^18 eV | We describe the current status of the High Resolution Fly's Eye detector. Event reconstruction and associated systematics for stereo reconstruction are discussed and recent preliminary results on the study of the composition of ultra-high energy cosmic rays by the Xmax method are presented. These r... | Ultra-high energy cosmic rays; Fluorescence; Stereo detection | 2002 |
| 9 |
 | Boehme, Christoph | Light-intensity and temperature dependence of trap-dangling bond recombination in hydrogenated microcrystalline silicon | A quantitative study of the trap-dangling bond tunneling recombination in hydrogenated microcrystalline silicon (μc-Si:H) is presented. The transition coefficients were measured at various light exposures and temperatures between T= 10 K and T= 140 K using time-domain measurements of spin-dependen... | Hydrogenated microcrystalline silicon; Spin-dependent recombination | 2002 |
| 10 |
 | Dawson, Kyle | Masses of high-redshift clusters via SZ effect observations | We present Sunyaev-Zel'dovich Effect (SZE) observations of distant, highly X-ray luminous clusters of galaxies. We use the SZE data to constrain their total masses, independent of X-ray observations. To do this, we assume the clusters have the same gas mass fraction as that derived from SZE measure... | Sunyaev-Zel'dovich Effect; X-rays; Redshift | 2002 |
| 11 |
 | Lupton, John Mark | Molecular thermometer based on long-lived emission from platinum octaethyl porphyrin | A highly sensitive molecular thermometer based on platinum octaethyl porphyrin, which can be employed in a range of environments, is presented. The thermal activation of the emission spectrum results in a change in emission intensity by an order of magnitude over a temperature range of 45 K about ro... | Molecular thermometer; Platinum octaethyl porphyrin | 2002 |
| 12 |
 | Vardeny, Zeev Valentine | Multiple resonances in microdisk lasers of ∏-conjugated polymers | We have fabricated microdisk lasers from p-conjugated polymers that show multiline emission spectrum upon optical excitation. Using Fourier transform analysis, each emission line is assigned integer to an interger Bessel function that helps to estimate the field distribution inside the photoexcited ... | Multiple resonances; Microdisks; Microdisk lasers; pi-conjugated polymers | 2002 |
| 13 |
 | Lupton, John Mark | On-chain defect emission in electroluminescent polyfluorenes | We present time-resolved photoluminescence measurements on a range of poly- and oligofluorenes with different molecular weights in both dilute solution and thin films. The commonly observed parasitic broad green emission band, which has previously been attributed to an excimer, is identified in all... | Defect emission; Parasitic broad green emission band | 2002 |
| 14 |
 | Williams, Clayton C. | Single electron tunneling to insulator surfaces detected by electrostatic force | The detection of single-electron tunneling events between a metallic scanning probe tip and an insulating surface is demonstrated by an electrostatic force method. When a voltage-biased oscillating atomic force microscopy tip is placed within tunneling range of the surface of an insulator, single... | Single electron; Tunneling events; Scanning tunneling microscope | 2002 |
| 15 |
 | Symko, Orest George | Size considerations in interfacing thermoacoustic coolers with electronics | Small 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; Miniturization | 2002 |
| 16 |
 | Vardeny, Zeev Valentine | Conjugation-length dependence of spin-dependent excition formations rates in ∏-conjugated oligomers and polymers | We have measured the ratio, r =ơ s/ơT of the formation cross section, ơ of singlet and triplet excitons from polarons in ∏-conjugated oligomer and polymer films, using a spectroscopic technique we developed recently. We discovered a universal relation between r and the conjugation length (CL): ... | pi-conjugated polymers; Conjugation length; Polaron recombination | 2002-04 |
| 17 |
 | Gondolo, Paolo | Cosmic ray positron excess and neutralino dark matter | Using 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; Annihilations | 2002-02 |
| 18 |
 | Wu, Yong-Shi | Deformed Hubbard operator, bosonization, and phase diagram of the one-dimensional t-J model | We present an analytic study of the phase diagram of the one-dimensional t-J model and a couple of its cousins. To deal with the interactions induced by the no double occupancy constraints, we introduce a deformation of the Hubbard operators. When the deformation parameter ∆ is small, the induced... | Hubbard operator; Bosonization; Deformation; t-J model | 2002-10 |
| 19 |
 | Vardeny, Zeev Valentine | Excited-state relaxation in ∏-conjugated polymers | We study ultrafast relaxation processes of odd- (Bu) and even-parity (Ag) exciton states in poly(p-phenylene vinylene) derivatives. The Bu states are studied using a regular two-beam pump-and-probe spectroscopy, which can monitor vibronic relaxation and exciton diffusion. In order to observe the A... | Ultrafast relaxation; Excited-state relaxation; pi-conjugated polymers; PPV | 2002-05 |
| 20 |
 | DeTar, Carleton | Heavy-light decay constants with three dynamical flavors | We present preliminary results for the heavy-light leptonic decay constants in the presence of three light dynamical flavors. We generate dynamical configurations with improved staggered and gauge actions and analyze them for heavy-light physics with tadpole improved clover valence quarks. When th... | Leptonic decay; Decay constants | 2002-03 |
| 21 |
 | Lupton, John Mark | Intrinsic room-temperature electrophosphorescence from a π-conjugated polymer | Electrically induced phosphorescence from a poly(para-phenylene) ladder-type polymer is observed for the first time and characterized using time resolved spectroscopy. Short-lived phosphorescence is also observed in gated fluorescence spectra and is found to be quenched reversibly by oxygen. Therm... | pi-conjugated polymers; Electrophosphorescence; Ladder-type polymer; Gated fluorescence spectra | 2002-09 |
| 22 |
 | DeTar, Carleton | Lattice calculation of heavy-light decay constants with two flavors of dynamical quarks | We present results for f B , f Bs , f D , f Ds and their ratios in the presence of two flavors of light sea quarks (Nf52). We use Wilson light valence quarks and Wilson and static heavy valence quarks; the sea quarks are simulated with staggered fermions. Additional quenched simulations with nonpe... | Wilson quarks; Chiral perturbation | 2002-11 |
| 23 |
 | Lupton, John Mark | Nonequilibrium polariton dynamics in organic microcavities | Microcavities containing a J-aggregate forming organic dye were prepared in the strong-coupling regime. Changing the position of the neat organic films within the microcavity allows a tuning of the giant Rabi splitting observed. We set the Rabi splitting to 25 meV and study the thermal activation o... | Nonequilibrium polariton dynamics; Organic microcavities; Optical microcavities; Rabi splitting; Light-matter interactions; Arrhenius activation | 2002-08 |
| 24 |
 | Wu, Yong-Shi | On gauge invariance of noncommutative Chern-Simons theories | Motivated by possible applications to condensed matter systems, in this paper we construct U(N) noncommutative Chern-Simons (NCCS) action for a disc and for a double-layer geometry, respectively. In both cases, gauge invariance severely constrains the form of the NCCS action. In the first case, it ... | 2002-05 | |
| 25 |
 | Lupton, John Mark | Origin of spectral broadening in amorphous π-conjugated amorphous semiconductors | We present a study of the picosecond fluorescence dynamics of p-conjugated semiconducting organic dendrimers in the solid state. By varying the degree of branching within the dendrons, referred to as the dendrimer generation, a control of intermolecular spacing of the emissive core and therefore o... | pi-conjugated polymers; pi-conjugated semiconductors; Spectral broadening; Solid state; Picosecond fluorescence dynamics | 2002-10 |