Search results for "electromagnetic [current]"
showing 10 items of 1008 documents
Theoretical study of the discrete and continuum spectrum of BeH
2008
The transition intensities supplied in this Letter are directly connected with a description of the discrete and continuum spectrum of BeH. An attempt to meet our goal requires the calculation of the absorption oscillator strengths of several transitions to Rydberg states of BeH, together with differential oscillator strengths which give rise to different dipole-allowed photoionization channels from the molecular ground state. The calculations have been performed with the molecular-adapted quantum defect orbital (MQDO) approach. Predictions of new spectroscopic data on BeH at energies where high Rydberg transitions can take place, including the continuum region of the spectrum have been mad…
Total absorption studies of high priority decays for reactor applications: 86Br and 91Rb
2017
Preliminary results from beta decay studies of nuclei that are important for reactor applications are presented. The beta decays have been studied using the total absorption technique (TAS) and the pure beams provided by the JYFLTRAP system at the IGISOL facility of the University of Jyväskylä. peerReviewed
Limitations of electron cyclotron resonance ion source performances set by kinetic plasma instabilities.
2015
Electron cyclotron resonance ion source (ECRIS) plasmas are prone to kinetic instabilities due to anisotropy of the electron energy distribution function stemming from the resonant nature of the electron heating process. Electron cyclotron plasma instabilities are related to non-linear interaction between plasma waves and energetic electrons resulting to strong microwave emission and a burst of energetic electrons escaping the plasma, and explain the periodic oscillations of the extracted beam currents observed in several laboratories. It is demonstrated with a minimum-B 14 GHz ECRIS operating on helium, oxygen, and argon plasmas that kinetic instabilities restrict the parameter space avail…
A Theoretical Model for Excitation Energy Transfer in Chlorosomes: Lamellar and Rod-Shaped Antenna Structures
2008
A model based on exciton theory is presented for description of excitation energy transfer in chlorosomes. Three models to describe the internal organization of the pigments inside the chlorosome were considered, a stack of single-wall rods, a stack of double-wall rods and a stack of lamellae directed along the long axis of the chlorosome. Simulated absorption, circular dichroism and linear dichroism spectra of single-wall rod and the lamella structures turned out to be practically identical. It was shown that rod—rod interactions may localize the exciton states in the regions of a rod facing a neighboring rod. Such localized states provide a fast excitation energy transfer mechanism in per…
Exciton description of chlorosome to baseplate excitation energy transfer in filamentous anoxygenic phototrophs and green sulfur bacteria.
2013
A description of intra-chlorosome and from chlorosome to baseplate excitation energy transfer in green sulfur bacteria and in filamentous anoxygenic phototrophs is presented. Various shapes and sizes, single and multiwalled tubes, cylindrical spirals and lamellae of the antenna elements mimicking pigment organization in chlorosomes were generated by using molecular mechanics calculations, and the absorption, LD, and CD spectra of these were predicted by using exciton theory. Calculated absorption and LD spectra were similar for all modeled antenna structures; on the contrary, CD spectra turned out to be sensitive to the size and pigment orientations in the antenna. It was observed that, bri…
Observation of inclined EeV air showers with the radio detector of the Pierre Auger Observatory
2018
With the Auger Engineering Radio Array (AERA) of the Pierre Auger Observatory, we have observed the radio emission from 561 extensive air showers with zenith angles between 60 and 84. In contrast to air showers with more vertical incidence, these inclined air showers illuminate large ground areas of several km2 with radio signals detectable in the 30 to 80 MHz band. A comparison of the measured radio-signal amplitudes with Monte Carlo simulations of a subset of 50 events for which we reconstruct the energy using the Auger surface detector shows agreement within the uncertainties of the current analysis. As expected for forward-beamed radio emission undergoing no significant absorption or sc…
Condensation and thermalization of classsical optical waves in a waveguide
2011
http://pra.aps.org/; International audience; We consider the long-term evolution of a random nonlinear wave that propagates in a multimode optical waveguide. The optical wave exhibits a thermalization process characterized by an irreversible evolution toward an equilibrium state. The tails of the equilibrium distribution satisfy the property of energy equipartition among the modes of the waveguide. As a consequence of this thermalization, the optical field undergoes a process of classical wave condensation, which is characterized by a macroscopic occupation of the fundamental mode of the waveguide. Considering the nonlinear Schrödinger equation with a confining potential, we formulate a wav…
MICROWAVE EFFECTS ON ACETYLCHOLINE-INDUCED CHANNELS IN CULTURED CHICK MYOTUBES
1988
The behavior of cultured myotubes from chick embryos exposed to microwaves has been experimentally analyzed. Recordings of acetylcholine-induced currents have been obtained via patch-clamp techniques using both cell-attached (single-channel current recording) and whole-cell (total current recording) configurations. During the exposure to low-power microwaves the frequency of the ACh-activated single channel openings decreased, while the ACh-induced total current showed a faster falling phase. Channel open time and conductance were not affected by microwave irradiation. It is concluded that the exposure to microwaves increases the rate of desensitization and decreases the channel opening pro…
Bis(stilbenyl)squaraines — Novel pigments with extended conjugation
1996
Abstract We report on the synthesis of a novel type of squaraines ( 11a-f, 17c ) in which the conjugation of the chromophore is extended by stilbene units. These pigments exhibit absorption bands which have their maxima at the end on the Vis region and reach partly into the NIR.
ChemInform Abstract: Bis(stilbenyl)squaraines. Novel Pigments with Extended Conjugation.
2010
Abstract We report on the synthesis of a novel type of squaraines ( 11a-f, 17c ) in which the conjugation of the chromophore is extended by stilbene units. These pigments exhibit absorption bands which have their maxima at the end on the Vis region and reach partly into the NIR.