163,581 research outputs found
Kramers Escape Rate in Nonlinear Diffusive Media
No full textIn this paper, we study nonlinear Kramers problem by investigating overdamped systems ruled by the one-dimensional nonlinear Fokker-Planck equation. We obtain an analytic expression for the Kramers escape rate under quasistationary conditions by employingIn this paper, we study nonlinear Kramers problem by investigating overdamped systems ruled by the one-dimensional nonlinear Fokker-Planck equation. We obtain an analytic expression for the Kramers escape rate under quasistationary conditions by employing a metastable potential and its predictions are in excellent agreement with numerical simulations. The results exhibit the anomalies due to the nonlinearity in W that the escape rate grows with D and drops as mu becomes large at a fixed D. Indeed, particles in the subdiffusive media (mu>1) can escape over the barrier only when D is above a critical value, while this confinement does not exist in the superdiffusive media (mu < 1)
Early Ordovician terrane accretion along the Gondwanian margin of the East Antarctic Craton: new Pb/Pb titanite ages from the Tonalite Belt, North Victoria Land, Antarctica
No full textEarly Palaeozoic subduction of the palaeo-Pacific plate and terrane accretion along the palaeomargin of the East Antarctic Craton is well-documented in North Victoria Land, where the Tonalite Belt is a complex of synkinematic intrusions emplaced within the Lanterman–Murchison Shear Zone at the boundary between the Wilson Terrane and the allochthonous Bowers Terrane. Stepwise leaching Pb/Pb and U–Pb studies of titanite separates carried out on two well-foliated samples of tonalites yielded ages of deformation bracketed between 490 and 480 Ma with an isochron age of 480 ±13 Myr. Ar/Ar and K–Ar ages of 477 Myr in the metamorphic rocks of accreted terranes point to fast cooling and uplift after accretion. The new titanite ages, compared with a regional distribution of magmatic and metamorphic ages, indicate an early Ordovician age for terrane collision and amalgamation. As a consequence of collision, subduction shifted to an outward position along the palaeomargin of the East Antarctic Craton
[Report to Chief J. E. Curry, by an unknown author #1]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
[Report to Chief J. E. Curry, by an unknown author #2]
No full textReport to Chief J. E. Curry, by an unknown author. The report contains a list of officers who gave depositions to the United States Attorney
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Kramers-Kronig Relations in Optical Materials Research
No full textThis is the first one-volume work to provide a thorough and comprehensive description of the physical background, rigorous theory and applications of Kramers-Kronig relations in the fields of linear and nonlinear optical spectroscopy. Currently, Kramers-Kronig relations have become basic tools in the investigation of the optical properties of materials. A brief presentation of the related data-retrieval technique, the maximum entropy method, is also given. The contents and style potentially make this a standard text for physicists, chemists and engineers interested in optical-materials research and development
Constraining Holocene sea levels using U-Th ages of phreatic overgrowths on speleothems from coastal caves in Mallorca (Western Mediterranean)
No full textPhreatic overgrowths on speleothems (POS) are carbonate formations deposited at the water table of caves in unique
karstic coastal settings having morphologies that can be directly related to sea level at the time of formation. The U-Th ages of
calcite and aragonite overgrowths collected from the modern water table in coastal caves on Mallorca (Cova de Cala Varques A
and Cova des Pas de Vallgornera) were determined using high-precision MC-ICPMS techniques. U-Th ages indicate that phreatic
carbonate deposition occurred between ca 2·8 and at least 0·6 ka BP and are in accord with an archeologically estimated age of
3·7–3·0 ka BP for a drowned prehistoric construction at a depth of 1 m below current sea level in a cave from the same area.
Speleothem δ13C and δ18O and chemical composition of cave pools provide supportive evidence that POS refl ect mixing between
seawater and brackish water table
Fiber-optic chemical sensing with Langmuir-Blodgett overlay waveguides
No full textFiber-optic chemical sensing has been demonstrated with a side-polished single-
mode optical fiber, evanescently coupled to chemically sensitive Langmuir-
Blodgett (LB) overlay waveguides. The sensors exhibit a channel-dropping
response centered on a wavelength that is dependent on the thickness and the
refractive index of the overlay waveguide. It has been shown that pH-sensitive
organic dyes proved to be suitable materials fur the formation of an overlay
waveguide whereas LB deposition provides the required thickness control. A
theoretical model of the sensor response, based on the Kramers-Kronig relations
and phase matching of the guided modes within the optical fiber and overlay
waveguide, shows good agreement with experimental results
Proeven over de warmte-afvoer van een splijtstofelement uit een kernreactor van het kokend water type
No full textApplied Science
Kramers-Kronig coherent receiver
No full textWe review the principles underpinning the Kramers-Kronig (KK) receiver operation and its various implementations. These include direct-detection based schemes, where the information-carrying signal is transmitted along with a CW field that is necessary for the implementation of the KK algorithm, as well as other schemes, where the CW is added at the receiver, owing to the availability of a local oscillator. Polarization-multiplexing with the KK receiver will also be discussed. Finally, an up-to-date review of the experimental implementations of KK transceiver solutions will be presented
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