Search results for "polarization."
showing 10 items of 1842 documents
Dual-polarization-pump CW laser operation in Nd3+:LiNbO3 channel waveguides fabricated by reverse proton exchange
2008
Abstract In this work, continuous-wave laser action at 1084.5 nm at room temperature in LiNbO 3 :Nd 3+ channel waveguides, fabricated by reverse proton exchange (RPE), is reported. The sample was pumped at λ = 808 nm in either σ or π-polarized configurations, TE- and TM-pumping schemes, being the laser emission π-polarized at all power levels. The laser characteristics, as function of the pumping scheme (TE or TM), have been obtained. In both cases, the laser emission was stable, without any reduction in the output power even under continuous pump operation at maximum power at room temperature, indicating high resistance to photorefractive damage.
Electrophysiological Analysis of Effects of Exogenous and Endogenous Adenosine in Hippocampal Slices
1988
Little doubt remains that adenosine serves a modulatory role in the nervous system (Sattin and Rail, 1970; Shimizu and Daly, 1970; Fredholm and Hedqvist, 1980; Phillis and Wu, 1981; Stone, 1981; Daly et al., 1984; Dunwiddie, 1985). While electrophysiologically active concentrations of adenosine have been found in the extracellular fluid, the source and control of the levels of this active adenosine are unclear. There are indications that adenosine is released (or coreleased) from synaptic endings, fulfilling a typical transmitter role (Burnstock, 1975, 1981; Nagy et al., 1986). A synaptic hyperpolarization in autonomic neurons has been identified as an adenosine-mediated potential (Akasu et…
Repetitive Transcranial Magnetic Stimulation
2019
Transcranial magnetic stimulation (TMS) represents a valuable neurophysiological technique useful for both research and clinical practice purposes [1]. TMS acts by inducing electrical fields which cause electric currents to flow in targeted cortical areas. These currents interact with the electrical activity of the brain and can depolarize cortical interneurons and/or projection neurons depending on the characteristics of the stimulation. The induced excitation can spread throughout the nervous system by the brain’s normal mechanisms of propagation of neuronal signals. In this way, TMS can also induce functional changes in areas remote to the stimulated cortical area, including both functio…
Model predictions of the ionic mechanisms underlying the beating and bursting pacemaker characteristics of molluscan neurons
1976
The general properties of the excitable membrane on molluscan pacemaker neurons can be described on the basis of a fair amount of experimental evidence available in the literature. The neuronal membrane exhibits under voltage clamp an initial inward current carried by both Na+ and Ca2+ ions, the time- and voltage-dependent characteristics of which are similar to that of other excitable structures. The conductance mechanism for the two ion species and the transport kinetics appear to be closely similar. The time course and amplitude of the delayed outward current carried by K+ ions shows a marked dependence on the membrane potential. Characteristic for the molluscan neurons is the existence …
Coupling of electrochemical, electrogravimetric and surface analysis techniques to study dithiocarbamate/bronze interactions in chloride media
2018
International audience; Interaction between ammonium pyrrolidinedithiocarbamate (PDTC) and bronze in 30 g L-1 NaCl was investigated at several concentrations between 0.1 and 10 mM by means of various electrochemical and spectroscopic techniques. Electrochemical measurements revealed a fast adsorption process of PDTC on Cu and Pb and the formation of a thick insulating and protective film with a high surface coverage. At high concentrations, PDTC prevents oxides formation. Surface analyses confirm PDTC adsorption on bronze mainly via interaction between sulphur atoms and Cu sites to form Cu I-PDTC complex.
Dynamic nuclear polarisation of biological matter
1986
Polarised targets as used in high energy physics experiments may be of considerable interest in biological structure research using polarized neutrons. So far, this promising method has been facing difficulties in getting reasonable polarization of the target nuclei. We report on a polarized "frozen spin" target which has been prepared from an enzyme dissolved in a mixture of heavy water and deuterated propanediol doped with a completely deuterated paramagnetic radical. Clusters of 700 protons defined by the structure of lysozyme embedded in a fully deuterated matrix were polarized to 75% within an hour by 4 mm microwave irradiation in a magnetic field of 2.5 tesla at a temperature of 0.3 K…
Phosphorescence emission and polarization of quinoline 3-carbonitrile
1993
Abstract The phosphorescence emission and excitation spectra and their polarization have been studied for quinoline 3-carbonitrile in methylcyclohexane and ethanol glasses at 77 K. From the results obtained in this molecule (τ=1.15 sec in ethanol, τ=1.04 sec in methylcyclohexane and out-of-plane polarization) it is concluded that the emission is orginated from a triplet state of 3 ππ * character. The two major spin-orbit coupling mechanisms through which the ππ * state of quinoline 3-carbonitrile acquires dipole-allowed character via nπ * states are: 1. In ethanol glass: 2. In methylcyclohexane glass:
"Table 3" of "Measurement of the transverse polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons produced in proton-proton collisions at $\sqrt{s}=…
2015
Transverse polarization POL of LAMBDA and LAMBDABAR hyperons as a function of PT.
"Table 2" of "Measurement of the transverse polarization of $\Lambda$ and $\bar{\Lambda}$ hyperons produced in proton-proton collisions at $\sqrt{s}=…
2015
Transverse polarization POL of LAMBDA and LAMBDABAR hyperons as a function of XF.
Polarization attraction using counter-propagating waves in optical fiber at telecommunication wavelengths
2008
International audience; In this work, we report the experimental observation of a polarization attraction process which can occur in optical fibers at telecommunication wavelengths. More precisely, we have numerically and experimentally shown that a polarization attractor, based on the injection of two counter-propagating waves around 1.55 mu m into a 2-m long high nonlinear fiber, can transform any input polarization state into a unique well-defined output polarization state.