10,314 research outputs found
Application of wavelets to singular integral scattering equations
The use of orthonormal wavelet basis functions for solving singular integral
scattering equations is investigated. It is shown that these basis functions
lead to sparse matrix equations which can be solved by iterative techniques.
The scaling properties of wavelets are used to derive an efficient method for
evaluating the singular integrals. The accuracy and efficiency of the wavelet
transforms is demonstrated by solving the two-body T-matrix equation without
partial wave projection. The resulting matrix equation which is characteristic
of multiparticle integral scattering equations is found to provide an efficient
method for obtaining accurate approximate solutions to the integral equation.
These results indicate that wavelet transforms may provide a useful tool for
studying few-body systems.Comment: 11 pages, 4 figure
A Preliminary Look at the Physics Reach of a Solar Neutrino TPC: Time-Independent Two Neutrino Oscillations
This paper will discuss the physics reach of a solar neutrino TPC containing
many tons of He4 under high pressure. Particular attention is given to the LMA
and SMA solutions, which are allowed by current data, and which are
characterized by a lack of time-dependent phenomena (either summer-winter or
day-night asymmetries). In this case, the physics of neutrino masses and mixing
is all contained in the energy dependence of the electron neutrino survival
probability, (or in its reciprocal, the electron neutrino disappearance
probability).Comment: 19 pages, 12 figure
Figures of merit of thermoelectric and bolometric thermal radiation sensors
Figures of merit condensing the performance parameters of radiation sensors such as responsivity, noise equivalent power, and time constant in a single number can be useful for rating the performance of a particular sensor in comparison to other ones or to fundamental performance limits. The classification system and the figures of merit of radiation sensors introduced by R. C. Jones are revisited for thermal radiation sensors with the focus on thermopiles and bolometers. As a result it is stated that radiation thermopiles and bolometers should be classified differently: type III detectors for thermopiles vs. type II detectors for bolometers. Modified figures of merit are suggested and relations between them given. The figures of merit are applied in an overview on state-of-the-art thermopiles and bolometers operated at room temperature
Influence of the temperature on the depinning transition of driven interfaces
We study the dynamics of a driven interface in a two-dimensional random-field
Ising model close to the depinning transition at small but finite temperatures
T using Glauber dynamics. A square lattice is considered with an interface
initially in (11)-direction. The drift velocity v is analyzed for the first
time using finite size scaling at T = 0 and additionally finite temperature
scaling close to the depinning transition. In both cases a perfect data
collapse is obtained from which we deduce beta = 1/3 for the exponent which
determines the dependence of v on the driving field, nu = 1 for the exponent of
the correlation length and delta = 5 for the exponent which determines the
dependence of v on T.Comment: 5 pages, Latex, Figures included, to appear in Europhys. Let
The OutâofâPlane Deformation Frequency of the NH Group in the Peptide Link
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70613/2/JCPSA6-21-3-570-2.pd
Precision Measurement of the 29Si, 33S, and 36Cl Binding Energies
The binding energies of 29Si, 33S, and 36Cl have been measured with a
relative uncertainty using a flat-crystal spectrometer.
The unique features of these measurements are 1) nearly perfect crystals whose
lattice spacing is known in meters, 2) a highly precise angle scale that is
derived from first principles, and 3) a gamma-ray measurement facility that is
coupled to a high flux reactor with near-core source capability. The binding
energy is obtained by measuring all gamma-rays in a cascade scheme connecting
the capture and ground states. The measurements require the extension of
precision flat-crystal diffraction techniques to the 5 to 6 MeV energy region,
a significant precision measurement challenge. The binding energies determined
from these gamma-ray measurements are consistent with recent highly accurate
atomic mass measurements within a relative uncertainty of .
The gamma-ray measurement uncertainties are the dominant contributors to the
uncertainty of this consistency test. The measured gamma-ray energies are in
agreement with earlier precision gamma-ray measurements.Comment: 13 pages, 4 figure
Spectra of Homologous Series of Monosubstituted Amides
Infrared spectra of the pure liquid and of dilute solution were observed for Nâmethyl, Nâethyl, Nâpropyl, and Nâbutyl acetamides and propionamides and of Nâdeuterated Nâbutylacetamide. Also infrared spectra of N15âbutylacetamide and Nâdeuterated N15âbutylacetamide and the Raman spectra of Nâbutylacetamide and Nâdeuterated Nâbutylacetamide were observed. In each series a band in the higher members was related to each band of the Nâmethyl compound on the basis of similarity in frequency, intensity, band width, and the influence of dilution. In Nâmethylacetamide and Nâbutylacetamide bands thus related were found to have also similar Raman activities and similar shifts on replacing the peptide hydrogen by deuterium. The extra bands could be related systematically to the extra CH2 groups. The implications of these results in protein spectroscopy and in the spectroscopic study of homologous series is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70627/2/JCPSA6-29-5-1097-1.pd
Superaging correlation function and ergodicity breaking for Brownian motion in logarithmic potentials
We consider an overdamped Brownian particle moving in a confining
asymptotically logarithmic potential, which supports a normalized Boltzmann
equilibrium density. We derive analytical expressions for the two-time
correlation function and the fluctuations of the time-averaged position of the
particle for large but finite times. We characterize the occurrence of aging
and nonergodic behavior as a function of the depth of the potential, and
support our predictions with extensive Langevin simulations. While the
Boltzmann measure is used to obtain stationary correlation functions, we show
how the non-normalizable infinite covariant density is related to the
super-aging behavior.Comment: 16 pages, 6 figure
Efeito do zinco no nĂvel da colectina conglutinina e a relação com a incidĂȘncia de enfermidades em bezerros.
Mid-Infrared Emission from E+A Galaxies in the Coma Cluster
We have used ISO to observe at 12m seven E+A galaxies plus an additional
emission line galaxy, all in the Coma cluster. E+A galaxies lacking narrow
emission lines have 2.2m to 12m flux density ratios or limits similar
to old stellar populations (typical of early-type galaxies). Only galaxies with
emission lines have enhanced 12m flux density. Excess 12m emission is
therefore correlated with the presence of on-going star formation or an active
galactic nucleus (AGN).
By comparing the current star formation rates with previous rates estimated
from the Balmer absorption features, we divide the galaxies into two groups:
those for which star formation has declined significantly following a dramatic
peak 1 Gyr ago; and those with a significant level of ongoing star
formation or/and an AGN. There is no strong difference in the spatial
distribution on the sky between these two groups. However, the first group has
systemic velocities above the mean cluster value and the second group below
that value. This suggests that the two groups differ kinematically.
Based on surveys of the Coma cluster in the radio, the IRAS sources, and
galaxies detected in H emission, we sum the far infrared luminosity
function of galaxies in the cluster. We find that star formation in late type
galaxies is probably the dominant component of the Coma cluster far infrared
luminosity. The presence of significant emission from intracluster dust is not
yet firmly established. The member galaxies also account for most of the far
infrared output from nearby rich clusters in general.Comment: AAS Latex, accepted for publication in Ap
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