1 - 25 of 1,920
Number of results to display per page
CreatorTitleDescriptionSubjectDate
1 Femtosecond dynamics of quasi-particles in YBa2Cu3O7-δ superconductor filmsWe have studied the transient electronic response of YBa2Cu307-δ epitaxialy grown H T c superconductor thin films in the femtosecond time domain, using transient photoinduced reflectivity (AR) with 60 fsec time resolution. For temperatures T>Tc only a bolometric signal was observed with ARrO. For ...Femtosecond dynamics; YBa2Cu3O7-8; Transient electronic response; Transient optical response1991-03
2 Charge transfer complexes of 2,4,6-tricyano-s-triazine with tetrathiafulvalene (TTF) and N,N,N' ,N'-tetramethyl-p-phenylenediamine (TMPD)Reaction of 2,4,6-tricyano-s-triazine (TCT) with tetrathiafulvalene (TTF) and N,N,N',N'-tetramethylp-phenylenediamine (TMPD) leads to 1 : 1 charge transfer complexes. The crystal structures of the TTF[TCT], as well as the decomposition product due to hydrolysis of the [TMPD][TCT], i.e. HTMPD]+[2,4-d...Electron; Solution; Hydrolysis2002
3 Spin frustration and metamagnetic behavior in a molecular-based quasi 1-D-ferrimagnetic chain: (MnTPP)(TCNE)We report an experimental observation of spin frustration and metamagnetic behavior in a quasi-1D ferrimagnetic chain, (MnTPP) + (TCNE) -. Metastability, hysteresis effects, and irreversibility of thermal and magnetic histories are observed in magnetization measurements. The "memory" phenomenon is ...Magnetic; Magnetization; Anisotropy1993
4 Floating of the modulation wave and phase pinning in incommensurate Rb2ZnBr4Nuclear-magnetic-resonance measurements in incommensurate Rb2ZnBr4 show the existence of regions where the modulation wave is floating. The floating regions coexist with other regions where the modulation wave is static. Impurity phase pinning and a roughening of the modulation wave at higher temper...Floating; Incommensurate phase; Phason mode; Lattices1983
5 Anomalous optical and ESR properties of doped polydiethynylsilanesThe optical, transport, and ESR properties of soluble conducting four-membered polydiethynylsilane heterocycles are described. The undoped one-dimensional gap is 2.0 eV in both films and solutions; no photoluminescence is observed. I2 doping induces a single absorption band at -1.05 eV in solutions...Polydiethynylsilane; Doped polydiethynylsilanes1991-09
6 Hadronic spectrum of the quark plasmaWe have carried out a numerical simulation in SU(3) lattice gauge theory with four flavors of low-mass staggered fermions at zero baryon-number density in the vicinity of the high-temperature phase transition on 6x 103 and 6x 102x20 lattices. Static screening masses (static susceptibilities) were m...Hadronic matter; Quark plasma; Chiral symmetry; Phase transitions1987-07
7 Scaling tests of the improved Kogut-Susskind quark actionImproved lattice actions for Kogut-Susskind quarks have been shown to improve rotational symmetry and flavor symmetry. In this work we find improved scaling behavior of the r and nucleon masses expressed in units of a length scale obtained from the static quark potential, and better behavior of the ...Instantons; Static potential2000-04
8 Optical bias control of dispersive relaxations in α-SI:HRelaxation of the photoinduced ir absorption band in a-Si:H was studied in the microsecond time domain as a function of cw bias illumination. The decays follow a power law t-a where the dispersion parameter a increases with bias illumination. At low temperatures, a increases linearly with the stead...Optical bias; Dispersive relaxations; Amorphous silicon; a-Si:H; Photoinduced absorption; Bias-controlled tunneling; Multiple trapping1984-01
9 Conus peptides as tools for the neuroscientistRecombinant DNA technology has had a powerful impact on understanding receptors and ion channels, the key components in the nervous system that are involved in intercellular communication. Cloning genes encoding these proteins has revealed that for every receptor and ion channel type, multiple molec...Conus peptides; Conotoxins1993
10 Critical behavior in Nt=4 staggered fermion thermodynamicsQuantum chromodynamics with two zero mass flavors is expected to exhibit a phase transition with O(4) critical behavior. Fixing the universality class is important for phenomenology and for facilitating the extrapolation of simulation data to physical quark mass values. Other groups have reported r...Staggered fermions; Phase transitions2000-01
11 Open syntaxin docks synaptic vesiclesSynaptic vesicles dock to the plasma membrane at synapses to facilitate rapid exocytosis. Docking was originally proposed to require the soluble N-ethylmaleimide-sensitive fusion attachment protein receptor (SNARE) proteins; however, perturbation studies suggested that docking was independent of the...2007
12 Crystallization of the MS2 translational repressor alone and complexed to bromouridineThe coat protein from the MS2 bacteriophage plays a dual role by encapsidating viral RNA and also by binding RNA as a translational repressor. In order to study the isolated dimer in a conformation not influenced by capsid interactions, a mutant molecule was crystallized that is defective in capsid ...Crystallization; RNA Bacteriophage; RNA Hairpin; Translational Repressor1995
13 Time variation of Newton's gravitational constant in superstring theoriesThe present time variation of coupling constants in superstring theories with currently favorable internal backgrounds critically depends on the shape of the potential for the size of the internal space. If the potential is almost flat, as in perturbation theory to all orders, the value of G/G for N...Gravitational constant; Time variation1986-10
14 Grupos funcionales en arbustos deserticos del norte de Chile, definidos sobre la base de las fuentes de agua utilizadasLa productividad primaria y la estructura de la vegetación en ecosistemas áridos están determinadas por la disponibilidad de agua. En un estudio realizado en el secano costero del norte-centro de Chile (29/43'S; 71/14'O, 300 m) se compararon los mecanismos de utilización de distintas fuentes de...Grupos funcionales; Functional groups; Arbustos deserticos; Desert shrubs; Fuentes de agua; Water sources; Water availability; Arid ecosystems; Pastoreo con caprinos; Goat overgrazing1999-01-01
15 Infrared ultrafast optical probes of photoexcitations in ∏-conjugated organic semiconductorsWe measured the ultrafast dynamics of photoexcitations in a variety of semiconductor ∏-conjugated polymer films and solutions, in the spectral range from 0.13 eV to 1.05 eV and time domain from 100 fs to 800 ps. The measurements were made in the low signal regime, where the relative changes in tra...Infrared ultrafast optical probes; Photoexcitations; Ultrafast dynamics; MEH-PPV2005
16 Housekeeping gene xanthine oxidoreductase is necessary for milk fat droplet enveloping and secretion: gene sharing in the lactating mammary gland.Xanthine oxidoreductase (XOR) is the rate-limiting enzyme in purine catabolism occurring in most cell types. However, this housekeeping gene is expressed at very high levels in a number of mammalian tissues including the lactating mammary epithelium, suggesting additional roles for XOR in these tiss...Body Weight; Cell Differentiation; Cell Membrane; Epithelium2002-12-15
17 Characterization of lysozyme messenger and lysozyme synthesized in vitroIn vitro systems for protein systhesis have been in wide use for about 10 years. In most of the early work protein synthesis was measured by following the incorporation of radioactive amino acids into acid precipitable material. This test cannot distinguish between the synthesis of complete, activ...Lysozyme Messenger; Lysozyme Synthesized; Protein Synthesis1969
18 NMR relaxation study of molecular motions between unequal potential wells in solid trans, trans- muconodinitrileWe report observations of extremely unusual proton NMR relaxation rates in solid trans, transmuconodinitrile (TMD, N=C-CH = CH-CH = CH-C = N). In particular we measured, over the temperature range 77-423 °K, proton dipolar relaxation times Tw and spin lattice relaxation times Tt (at 24 and 58 MH...NMR; Nuclear magnetic resonance; Lattices; Relaxation time1977
19 An analog light scattering experiment of hexagonal icelike particles. part I: experimental apparatus and test measurementsAn experimental apparatus to measure the scattering properties of hexagonal icelike particles in the analog manner at the helium neon laser wavelength of 0.633 mm has been designed and built. The instrument consists of an array of 36 highly sensitive and linear photodiode detectors that are positi...1999
20 Macular pigment Raman detector for clinical applicationsClinical studies of carotenoid macular pigments (MP) have been limited by the lack of noninvasive, objective instruments. We introduce a novel noninvasive optical instrument, an MP Raman detector, for assessment of the carotenoid status of the human retina in vivo. The instrument uses resonant excit...Diagnosis, Computer-Assisted; Equipment Failure Analysis; Sensitivity and Specificity2004
21 Self-assembly of coordinative supramolecular polygons with open binding sitesThe design and synthesis of coordinative supramolecular polygons with open binding sites is described. Coordination-driven self-assembly of 2,6-bis(pyridin-4-ylethynyl)pyridine with 60? and 120? organoplatinum acceptors results in quantitative formation of a supramolecular rhomboid and hexagon, resp...2010
22 Sensory information processing and symbolic computation (1 Jan. 1975 - 30 June 1975)This research uses digital computation to investigate processes, both linear and nonlinear, for the filtering. restoration, enhancement, bandwidth reduction, distortion immunization and analysis of both visual and auditory information.Sensory information processing; Symbolic computation; Auditory information; Visual information1973
23 Ultrafast femtosecond relaxation processes in luminescent and nonluminescent conducting polymersWe have employed the time-resolved photomodulation (PM) technique to study the photoexcitation dynamics in a luminescent (Si-PT) and nonluminescent ( s-(CH)x ) conducting polymers in the low signal limit. In each polymer, we identify two exponential decay processes in the PM decay, with characterist...Ultrafast femtosecond relaxation; Femtosecond spectroscopy; Pump-and-probe technique; PM decay; Polarization memory; Bi-exponential response1997
24 Nuclear magnetic resonance solution conformation of α-conotoxin AuIB, an α3ß4 subtype-selective neuronal nicotinic acetylcholine receptor antagonistThe neuronal nicotinic acetylcholine receptors constitute a highly diverse group, with subtypes consisting of pentameric combinations of α and ß subunits. α-Conotoxins are a homologous series of small peptides that antagonize these receptors. We present the three-dimensional solution structure ...Conotoxins; a-conotoxin AuIB2000
25 Photo induced infrared active phonons in trans polyacetyleneWe measured photogenerated ir active phonons in trans-(CH) by the photoinduced absorption technique. A correlation was found to exist with a photoinduced absorption band in which electronic transitions are involved. Our results show photoproduction of free charged defects with long lifetimes.Photoinduced phonons; Trans polyacetylene1983-06
1 - 25 of 1,920