UScholar Works
 
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CreatorTitleDescriptionSubjectDate
126 Mattis, Daniel C.Eigenstates of excitons near a surfaceThe exact eigenstates and energies of an electron and a hole of equal effective masses, with an attractive δ-function interaction and hard-wall repulsion at the surfaces of a solid, are classified and obtained explicitly for a solid of arbitrary thickness. Both bound and scattering states of the e...Eigenstates; Frenkel excitons1978-10
127 Poulter, Charles DaleFarnesyl pyrophosphate synthetase. Mechanistic studies of the 1'-4 coupling reaction with 2-fluorogeranyl pyrophosphate.The mechanism of the 1'-4 coupling reaction between isopentenyl pyrophosphate and geranyl pyrophosphate catalyzed by farnesyl pyrophosphate synthetase from porcine liver was studied with the allylic substrate analogue 2-fluorogeranyl pyrophosphate. 2-Fluorogeranyl pyrophosphate is an alternate subst...Kinetics; Liver; Mass Spectrometry; Organophosphorus Compounds; Protein Binding1978-10-25
128 Ailion, David CharlesNuclear magnetic resonance study of diffusion of bound and free fluorine interstitials in alkaline earth fluorides doped with trivalent impuritiesWhen alkaline-earth fluorides are doped with trivalent impurities, interstitial fluorines are created to maintain charge neutrality. We have performed NMR dipolar-energy relaxation measurements over a wide temperature range and have observed the diffusion of both free and locally bound fluorine inte...Diffusion; Motion; Crystals; NMR; Fluorine1979
129 Miller, Joel StevenPotential technology directions of molecular metalsIn the past decade, anisotropic molecular conductors have been found which possess unusual electrical, optical, magnetic, and in some cases mechanical properties. Exploiting these properties for specific devices is inevitable, and a number of diverse applications of molecular metals have been repor...Molecular metals1979
130 Miller, Joel Steven; Epstein, Arthur J.Elastic properties of (N(CH3)3H) (I) (TCNQ)We present the results of a study of the temperature dependence of the Young's modulus and internal friction of (N(CH3 )3H)(I)(TCNQ). The Young's modulus was measured in a direction parallel to the TCNQ (tetracyanoquinodimethane) stacking axis using a vibrating reed technique. The results confirmed ...Metal-like, Conductivity, Magnetic1979
131 Potts, Wayne K.Gong method for capturing shorebirds and other ground-roosting speciesIn many shorebird studies it is necessary to capture adult birds. While shorebirds can often be trapped on the nest, capturing them away from the nest is usually very difficult and may require expensive equipment. After weeks of failure in our attempts to capture migrant and resident shorebirds in n...Gong method; Shorebirds; Capture; Ground-roosting1979
132 Ailion, David CharlesZeeman-quadrupole cross relaxation between two nuclear spin speciesWe derive an expression for the rate T / s ' of the cross relaxation between the Zeeman splitting of one nuclear spin species (/ spins, I = 1/2) and the quadrupole splitting of another spin species ( 5 spins, S > 1/2) via the IS dipolar interaction. We calculate T , s for the case of CFCL2-CFCL2 (/ ...Spin species; Spin-lattice relaxation1979
133 Boll, Steven F.Suppression of acoustic noise in speech using spectral subtractionA stand alone noise suppression algorithm is presented for reducing the spectral effects of acoustically added noise in speech. Effective performance of digital speech processors operating in practical environments may require suppression of noise from the digital waveform. Spectral subtraction offe...Suppression; acoustic noise; noise suppression algorithm; digital speech processors; Spectral subtraction1979
134 Miller, Joel Steven ; Epstein, Arthur J.Thermoelectric-power studies of (N-Methylphenazinium)x(Phenazine)1-x(Tetracyanoquinodimethanide), (0.5 <_ x <_ 1.0)Temperature-dependent thermoelectric-power (S) studies of (N-methylphenaziniurn)(x)- (phenazine) (1-x) (tetracyanoquinodimethanide) [(NMP)x(phen) (1-x)(TCNQ) 1 show that for x = 0.5, S(T) is indentical to that of (quinolinium) (TCNQ)2. S(T) for 0.5 <x < 1.0 is intermediate between that of (NMP)(TC...Semiconducting; Doping1979
135 Ailion, David CharlesNMR observations of molecular motions and Zeeman-quadrupole cross relaxation in 1,2- difluorotetrachloroethaneWe report measurements of "F NMR relaxation times Tu Tlf, TID, and T2 in the plastic crystal CFCL2-CFCL2 . From the data near the melting point, we obtain the jump time for translational selfdiffusion. At lower temperatures, we observe on the cold side of the T, and Tif minima an unusual field depe...NMR; Nuclear magnetic resonance; Order-disorder; Diffusion1979
136 Symko, Orest GeorgeCalibration of SQUID magnetometer for dilute alloy studiesA SQUID magnetometer used in the study of dilute magnetic alloys or other weak magnetic systems can be calibrated by using the nuclear paramagnetism of aluminum metal. This material is useful as a calibration standard since magnetic impurities such as Fe and Mn form no local moment. This calibration...SQUID magnetometer1979
137 Vardeny, Zeev ValentinePhonon anomalies in Cu halidesA great number of the observed phonon anomalies in the zinc-blende phase of Cu-halide crystals are explained by means of a dynamical model. It is assumed that a Cu ion populates four equivalent off-center sites or its ideal position. The off-center Cu+ population is temperature and pressure dependen...Phonon anomalies; Cu-halide crystals; Cuprous halides1979-03
138 Vardeny, Zeev ValentineDisorder-induced TA Raman lines in mixed Cu-halide crystalsThe Raman spectra of CuClxBr1=x and CuBrxI1=x solid solutions are shown to contain extremely intense disorder-induced first-order TA phonons. The intensity of these lines is a function of the concentration x, and is highest in CuCl0.6oBr0.40. The TA spectrum, well resolved at low temperature, fits...Cuprous halides; CuBr; CuCl; CuI; mixed Cu-halide crystals1979-03
139 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
140 Sokolsky, PierreSearch for new particles at the alternating-gradient-synchrotron beam dumpThis paper presents results of a beam-dump experiment performed at the Brookhaven alternating-gradient synchrotron to search for prompt sources of neutrinos and axionlike particles. We observe no excess of vµ or events, and no excess in neutral-current events over that expected from neutrinos from ...1979-05
141 Mattis, Daniel C.Molecular-field theory with correlationsWe derive an improved molecular-field theory for spins 1/2 from first principles. Formulas are obtained for use in cases when the fields, bonds, or occupation of the sites are random variables.Molecular-field theory; Spin glasses1979-05
142 Mattis, Daniel C.Ground-state symmetry in XY model of magnetismNumerical studies by Betts and Oitmaa have led those authors to conjecture that in the XY model the ground-state magnetization Mz is zero. This is a model of spins on a lattice with interactions - J(SnxSmx+SnySmy), that can also describe a hard-sphere boson fluid. In the present note I prove the c...Ground state; Magnetization; Bipartite lattice1979-06
143 Mattis, Daniel C.Soluble Ising model in 2+1/N dimensions and XY model in 1+1/N dimensionsThe XY model is exactly soluble on a comblike structure, by means of a modified Jordan-Wigner transformation. This method is used to reduce the transfer matrix of the Ising model, on planes which are joined to each other at one edge, to a soluble canonical form.Jordan-Wigner transformation1979-07
144 Poulter, Charles DalePrenyltransferase. Kinetic studies of the 1'-4 coupling reaction with avian liver enzyme.Prenyltransferase catalyzes the sequential, irreversible 1'-4 condensation of isopentenyl-PP with dimethylallyl-PP and geranyl-PP to yield farnesyl-PP. A kinetic study shows substrate inhibition by isopentenyl-PP at concentrations above 0.7 microM when the concentration of geranyl-PP is 1.0 microM o...Birds; Kinetics; Structure-Activity Relationship; Substrate Specificity1979-10-10
145 Miller, Joel StevenOptical and electron-energy-loss studies of the monomeric and dimeric phases of decamethylferrocenium tetracyanoquinodimethanide, (DMeFc)(TCNQ)The optical properties of the two crystallographic phases of 1:l decaniethylferrocenium tetracyanoauinodimethanide, (DMeFc)(TCNQ), have been measured from 0.1 to 10 eV. One phase consists of isolated paramagnetic TCNQ anion monomers while the other contains isolated diamagnetic dimers. The spectru...Ions; Spectrum1980
146 Davidson, Diane W.Competition and the structure of granivore communitiesWe trace the development of our investigations of granivory in desert ecosystems, illustrating the synthesis of the comparative and experimental approaches and noting the essential contributions of both. In the process, we also call attention to several major difficulties inherent to experimentatio...Granivory; Competition; Desert Ecosystems; Competitive investigations; Experimental investigations1980
147 Ailion, David CharlesNMR determination of structural domains in NaCNMeasurements of the first- and second-order quadrupole energy-level shifts are performed in a 23Na NMR experiment in a single crystal of NaCN. Twelve orthorhombic domains are found below the phase transition at 15°C. They consist of six pairs of domains with each one oriented by an angle 2/3 rel...NMR; Nuclear magnetic resonance; Crystals; Structural domains1980
148 Davidson, Diane W.Some consequences of diffuse competition in a desert ant communityExploitative and interference competition are investigated in detail in a community of six coexisting species of granivorous desert ants . A linear model that includes both direct and indirect competitive interactions is used to predict positive or negative correlations in the abundances of com...Ants; Arizona; California; Coexistence; Communities; Density specialization; Desert granivores; Resource partitioning1980
149 Golden, Kenneth M.Sea ice studies in the Weddell Sea aboard USCGC Polar SeaOur purpose was to investigate several of the characteristics of Weddell Sea pack ice that may affect the relative roles of dynamics and thermodynamics of pack ice development in this region. The total pack ice production and the movement of pack ice from its source area in the Weddell Sea is part...Floes.; Salinity; Formation1980
150 Vardeny, Zeev ValentinePhonon-polaritons in Cu halides: anomalies and their temperature dependenceThe polariton Raman spectra of CuCl, CuBr, and Cul crystals are studied at various temperatures of their zinc-blende phase. Two polar modes are proven to exist in CuCl at room temperature and below; their oscillator-strength ratio changes with temperature and follows the temperature dependence of ...Cuprous halides; CuBr; CuCl; CuI; Phonon anomalies; Temperature dependence; Zinc blende phase1980-03
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