2,136 research outputs found
Optical Constants of Magnesium Oxide in the Far Ultraviolet
Optical constants of magnesium oxide in far ultraviole
Biodiversity study of Southern Biscayne Bay and Card Sound 1968-1973
A multi-disciplinary investigation was conducted in southern Biscayne Bay and Card Sound from 1968 to 1973. The purpose of the investigation was to conduct an integrated study of the ecology of southern Biscayne Bay with special emphasis on the effects of the heated effluent from the Turkey Point fossil fuel power plant, and to predict the impact of additional effluent from the planned conversion of the plant to nuclear fuel. The results of this investigation have been discussed in numerous publications. This report contains the unpublished biology data that resulted from the investigation. (PDF contains 44 pages
Dynamical excitonic effects in metals and semiconductors
The dynamics of an electron--hole pair induced by the time--dependent
screened Coulomb interaction is discussed. In contrast to the case where the
static electron--hole interaction is considered we demonstrate the occurrence
of important dynamical excitonic effects in the solution of the Bethe--Salpeter
equation.This is illustrated in the calculated absorption spectra of noble
metals (copper and silver) and silicon. Dynamical corrections strongly affect
the spectra, partially canceling dynamical self--energy effects and leading to
good agreement with experiment.Comment: Accepted for publication on Phys. Rev. Let
Optical Constants of Lithium Fluoride in the Far Ultraviolet
Optical constants of lithium fluoride in far ultraviole
Methods of regularization for computing orbits in celestial mechanics
Numerical and analytical methods for orbit computation in celestial mechanics during and beyond collision by introduction of regularized coordinate
Critical properties of the double exchange ferromagnet Nd0.4Pb0.4MnO3
Results of a study of dc-magnetization M(T, H), performed on a Nd0.6Pb0.4MnO3
single crystal in the temperature range around T_C (Curie temperature) which
embraces the critical region | epsilon | = |T -T_C |/T_C <= 0.05 are reported.
The magnetic data analyzed in the critical region using the Kouvel-Fisher
method give the values for the T_C =156.47 +/- 0.06 K and the critical
exponents, beta = 0.374 +/- 0.006 (from the temperature dependence of
magnetization), and gamma = 1.329 +/- 0.003 (from the temperature dependence of
initial susceptibility). The critical isotherm M(T_C, H) gives delta = 4.547
+/- 0.1. Thus the scaling law gamma+beta=delta beta is fulfilled. The critical
exponents obey the single scaling-equation of state M(H, epsilon) = epsilon^b
f_+/- (H/epsilon^(beta + gamma)) where, f_+ for T > T_C and f_- for T< T_C. The
exponent values are very close to those expected for the universality class of
3D Heisenberg ferromagnets with short-range interactions.Comment: 19 pages, including 6 figure
Rapid characterisation of large earthquakes by multiple seismic broadband arrays
An automatic procedure is presented to retrieve rupture parameters for large earthquakes along the Sunda arc subduction zone. The method is based on standard array analysis and broadband seismograms registered within 30°–100° epicentral distance. No assumptions on source mechanism are required. By means of semblance the coherency of <i>P</i> waveforms is analysed at separate large-aperture arrays. Waveforms are migrated to a 10°&times;10° wide source region to study the spatio-temporal evolution of earthquakes at each array. The multiplication of the semblance source maps resulting at each array increases resolution. Start, duration, extent, direction, and propagation velocity are obtained and published within 25 min after the onset of the event. First preliminary results can be obtained even within 16 min. Their rapid determination may improve the mitigation of the earthquake and tsunami hazard. Real-time application will provide rupture parameters to the GITEWS project (German Indonesian Tsunami Early Warning System). The method is applied to the two <i>M</i>8.0 Sumatra earthquakes on 12 September 2007, to the <i>M</i>7.4 Java earthquake on 2 September 2009, and to major subduction earthquakes that have occurred along Sumatra and Java since 2000. Obtained rupture parameters are most robust for the largest earthquakes with magnitudes <i>M</i>&ge;8. The results indicate that almost the entire seismogenic part of the subduction zone off the coast of Sumatra has been ruptured. Only the great Sumatra event in 2004 and the <i>M</i>7.7 Java event on 17 July 2006 could reach to or close to the surface at the trench. Otherwise, the rupturing was apparently confined to depths below 25 km. Major seismic gaps seem to remain off the coast of Padang and the southern tip of Sumatra
Handling and analysis of ices in cryostats and glove boxes in view of cometary samples
Comet nucleus sample return mission and other return missions from planets and satellites need equipment for handling and analysis of icy samples at low temperatures under vacuum or protective gas. Two methods are reported which were developed for analysis of small icy samples and which are modified for larger samples in cometary matter simulation experiments (KOSI). A conventional optical cryostat system was modified to allow for transport of samples at 5 K, ion beam irradiation, and measurement in an off-line optical spectrophotometer. The new system consists of a removable window plug containing nozzles for condensation of water and volatiles onto a cold finger. This plug can be removed in a vacuum system, changed against another plug (e.g., with other windows (IR, VIS, VUV) or other nozzles). While open, the samples can be treated under vacuum with cooling by manipulators (cut, removal, sample taking, irradiation with light, photons, or ions). After bringing the plug back, the samples can be moved to another site of analysis. For handling the 30 cm diameter mineral-ice samples from the KOSI experiments an 80x80x80 cm glove box made out of plexiglass was used. The samples were kept in a liquid nitrogen bath, which was filled from the outside. A stream a dry N2 and evaporating gas from the bath purified the glove box from impurity gases and, in particular, H2O, which otherwise would condense onto the samples
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