Search results for "Spectroscopy"
showing 10 items of 10293 documents
Shine bright or live long: substituent effects in [Cu(N^N)(P^P)]+-based light-emitting electrochemical cells where N^N is a 6-substituted 2,2'-bipyri…
2016
We report [Cu(P^P)(N^N)][PF6] complexes with P^P = bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) and N^N = 6-methyl-2,2′-bipyridine (Mebpy), 6-ethyl-2,2′-bipyridine (Etbpy), 6,6′-dimethyl-2,2′-bipyridine (Me2bpy) or 6-phenyl-2,2′-bipyridine (Phbpy). The crystal structures of [Cu(POP)(Phbpy)][PF6]·Et2O, [Cu(POP)(Etbpy)][PF6]·Et2O, [Cu(xantphos)(Me2bpy)][PF6], [Cu(xantphos)(Mebpy)][PF6]·CH2Cl2·0.4Et2O, [Cu(xantphos)(Etbpy)][PF6]·CH2Cl2·1.5H2O and [Cu(xantphos)(Phbpy)][PF6] are described; each copper(I) centre is distorted tetrahedral. In the crystallographically determined structures, the N^N domain in [Cu(xantphos)(Phbpy)]+ and [Cu(…
Analytical measurements of fission products during a severe nuclear accident
2018
The Fukushima accident emphasized the fact that ways to monitor in real time the evolution of a nuclear reactor during a severe accident remain to be developed. No fission products were monitored during twelve days; only dose rates were measured, which is not sufficient to carry out an online diagnosis of the event. The first measurements were announced with little reliability for low volatile fission products. In order to improve the safety of nuclear plants and minimize the industrial, ecological and health consequences of a severe accident, it is necessary to develop new reliable measurement systems, operating at the earliest and closest to the emission source of fission products. Throug…
The effect of excipients on the stability and phase transition rate of xylazine hydrochloride and zopiclone
2015
The compatibility of thermodynamically unstable polymorph of two active pharmaceutical compounds (xylazine hydrochloride form X and zopiclone form C) with different excipients was investigated. The effects of the excipient and its amount in the sample on the thermal properties and possible chemical interactions were studied. The most commonly used excipients in the pharmaceutical industry - calcium carbonate, lactose hydrate, cellulose, magnesium stearate hydrate and calcium stearate hydrate were selected for this study. The dependence of the phase transition rate from an unstable to a more stable polymorph on the excipients and their amounts in the initial sample was analysed at 80°C, and …
Urea Glass Route as a Way to Optimize YAGG:Ce3+,Cr3+,Pr3+ Nanocrystals for Persistent Luminescence Applications
2022
A new approach for the synthesis of Y3Al2Ga3O12 (YAGG) nanophosphors allowing the preparation of crystallites with sizes starting from 45 nm is presented. The controllability of the energy and trap density of the resulting material samples by annealing temperature was confirmed by thermoluminescence (TL) measurements. It has been shown that the annealing of samples at temperatures up to 1300 degrees C does not cause any substantial growth of crystallites, still remaining below 100 nm, but leads to changes in the activation energy of the persistent luminescence (PersL) process. On the other hand, annealing above 1400 degrees C results in grain growth on the submicron scale, which was confirm…
Toxicity of fatty acid hydroperoxides towards Yarrowia lipolytica: Implication of their membrane fluidizing action
2007
Abstract Linoleic acid hydroperoxide (HPOD), substrate of hydroperoxide lyase, an enzyme of the lipoxygenase pathway, can be transformed into many aromatic compounds, the so-called “green notes”. The presence of linoleic acid hydroperoxide in the culture medium of Yarrowia lipolytica, the yeast expressing the cloned hydroperoxide lyase of green bell pepper, undoubtedly exerted an inhibition on the growth and a toxic effect with 90% of yeast cells died after 120 min of exposition in 100 mM HPOD solution. The increase in cell membrane fluidity evaluated by measuring fluorescence generalized polarization with the increasing concentration of HPOD in the medium confirmed the fluidizing action of…
Electronic structure of indium selenide probed by magnetoabsorption spectroscopy under high pressure
2010
We report on an investigation of the peculiar electronic structure of the layered semiconductor InSe by magneto-optical experiments under high pressure up to 5 GPa. Magneto-absorption spectroscopy is performed under pulsed magnetic field up to 53 T using a specific setup. Excitonic magnetofingerprints and high-field oscillatory magnetoabsorption yield significant details on the band structure. In addition, the application of an external pressure unveils phenomena that confirm the specific $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ model proposed for this compound on the basis of earlier measurements.
Mechanical characterization of TiO2 nanofibers produced by different electrospinning techniques
2015
Abstract In this work TiO2 nanofibers produced by needle and needleless electrospinning processes from the same precursor were characterized and compared using Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and in situ SEM nanomechanical testing. Phase composition, morphology, Young's modulus and bending strength values were found. Weibull statistics was used to evaluate and compare uniformity of mechanical properties of nanofibers produced by two different methods. It is shown that both methods yield nanofibers with very similar properties.
Atomic transition probabilities for selected Yb II lines emitted from a ferroelectric plasma source
2010
The relative intensities of several hundred emission lines of Yb II between 200 nm and 900 nm were obtained with the use of ferroelectric plasma source. These relative intensities obtained for lines from 21 energy levels have been used to determine the line branching fractions, which have then been combined with accurate experimental radiative lifetime measurements to give absolute transition probabilities for 111 Yb II lines. The obtained values were compared with theoretical and experimental data taken from available literature.
Chemistry of lanthanide–metal carbonyl systems: the ytterbium–chromium carbonyls interaction
2001
Abstract The interaction of the chromium carbonyl hydrides HCr2(CO)10− or HCr(CO)5− with Yb(acac)3·3H2O has been investigated, and the experimental conditions leading to the isolation of ytterbium–chromium carbonyl complex species are reported. Formulation of the coordination compounds produced by such interactions has been proposed on the basis of analytical data and IR spectroscopy.
Developments for resonance ionization laser spectroscopy of the heaviest elements at SHIP
2016
Abstract The experimental determination of atomic levels and the first ionization potential of the heaviest elements ( Z ⩾ 100 ) is key to challenge theoretical predictions and to reveal changes in the atomic shell structure. These elements are only artificially produced in complete-fusion evaporation reactions at on-line facilities such as the GSI in Darmstadt at a rate of, at most, a few atoms per second. Hence, highly sensitive spectroscopic methods are required. Laser spectroscopy is one of the most powerful and valuable tools to investigate atomic properties. In combination with a buffer-gas filled stopping cell, the Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniq…