Search results for "induced [background]"
showing 10 items of 366 documents
Integrated analytical methodologies for the study of corrosion processes in archaeological bronzes
2011
Abstract The investigations on structure and micro-chemical composition of archaeological metal alloys are needed in archaeometry. The aim of this study is devoted both to acquire information about their provenance and production technology, and to improve our understanding about the corrosion processes. In this paper we present the study of the corrosion phenomena of bronze samples, laboratory-made according to binary, ternary and quaternary alloys typical of Roman archaeometallurgical production through an integrated methodology based on the use of non or micro invasive physical techniques. Among the analysed samples, two were artificially aged through burial in the archaeological site of…
UV-Photoinduced Defects In Ge-Doped Optical Fibers
2005
We investigated the effect of continuous-wave (cw) UV laser radiation on single-mode Ge-doped H2- loaded optical fibers. An innovative technique was developed to measure the optical absorption (OA) induced in the samples by irradiation, and to study its dependence from laser fluence. The combined use of the electron spin resonance (ESR) technique allowed the structural identification of several radiation-induced point defects, among which the Ge(1) (GeO4 -) is found to be responsible of induced OA in the investigated spectral region.
Polymerization reactions and modifications of polymers by ionizing radiation
2020
International audience; Ionizing radiation has become the most effective way to modify natural and synthetic polymers through crosslinking, degradation, and graft polymerization. This review will include an in-depth analysis of radiation chemistry mechanisms and the kinetics of the radiation-induced C-centered free radical, anion, and cation polymerization, and grafting. It also presents sections on radiation modifications of synthetic and natural polymers. For decades, low linear energy transfer (LLET) ionizing radiation, such as gamma rays, X-rays, and up to 10 MeV electron beams, has been the primary tool to produce many products through polymerization reactions. Photons and electrons in…
Laser-induced plasma spectroscopy in near vacuum ultraviolet using ordinary spectrograph and ICCD
2002
An experimental setup to measure laser-induced plasma emission spectra with an ordinary Czerny-Turner spectrograph and intensified charge-coupled device in the near vacuum ultraviolet down to 130 nm is described. Spectra of bromine, chlorine and iodine were recorded to demonstrate the performance of the setup.
More than a pore: How voltage-gated calcium channels act on different levels of neuronal communication regulation.
2021
ABSTRACT Voltage-gated calcium channels (VGCCs) represent key regulators of the calcium influx through the plasma membrane of excitable cells, like neurons. Activated by the depolarization of the membrane, the opening of VGCCs induces very transient and local changes in the intracellular calcium concentration, known as calcium nanodomains, that in turn trigger calcium-dependent signaling cascades and the release of chemical neurotransmitters. Based on their central importance as concierges of excitation-secretion coupling and therefore neuronal communication, VGCCs have been studied in multiple aspects of neuronal function and malfunction. However, studies on molecular interaction partners …
The neurobiological bases for the pharmacotherapy of nicotine addiction.
2007
Nicotine, the major psychoactive agent present in tobacco, acts as a potent addictive drug both in humans and laboratory animals, whose locomotor activity is also stimulated. A large body of evidence indicates that the locomotor activation and the reinforcing effects of nicotine may be related to its stimulatory effects on the mesolimbic dopaminergic function. Thus, it is now well established that nicotine can increase in vivo DA outflow in the nucleus accumbens and the corpus striatum. The stimulatory effect of nicotine on DA release most probably results from its ability to excite the neuronal firing rate and to increase the bursting activity of DA neurons in the substantia nigra pars com…
An electrospray ionization Fourier transform ion cyclotron resonance mass spectrometric study of the gas-phase stabilities and fragmentation ofN-alky…
2006
Five N-alkylated ammonium resorcarene derivatives, differing either in the nitrogen atom or in the lower rim alkyl chain, were studied using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The main purpose was to clarify the fragmentation and the relative stabilities of the protonated molecules by collision-induced dissociation (CID) experiments. The results indicate that fragmentation of the upper rim alkyl amino substituents at the 2-position occurs readily. Variation in the gas-phase stabilities of these molecules was also observed. In addition, the proposed fragmentation pathways are depicted.
The minimal number of characters over a normal p-subgroup
2007
Abstract If N is a normal p-subgroup of a finite group G and θ ∈ Irr ( N ) is a G-invariant irreducible character of N, then the number | Irr ( G | θ ) | of irreducible characters of G over θ is always greater than or equal to the number k p ′ ( G / N ) of conjugacy classes of G / N consisting of p ′ -elements. In this paper, we investigate when there is equality.
Atomic spectroscopy: a review
2010
Atomic Absorption Spectrometry 4653 Flame Atomic Absorption Spectrometry 4653 Electrothermal Atomic Absorption Spectrometry 4654 Volatile Species Generation Atomic Absorption Spectrometry 4654 Direct Solids Atomic Absorption Spectrometry 4655 Continuum Source Atomic Absorption Spectrometry 4655 Atomic Fluorescence Spectrometry 4655 Atomic Emission Spectrometry 4656 DC Arc and Low-Power RF Radiation Sources 4656 Inductively Coupled Plasmas 4656 Microwave Induced Plasmas 4658 Microplasmas 4658 Laser Induced Breakdown Spectroscopy 4658 Glow Discharge Optical Emission and Mass Spectrometry 4660 Fundamental Studies 4660 Methodological Studies and Applications of GD-OES and GDMS 4661 New GD Sourc…