The temperature dependence of sensitized Er(3+) emission via localized states and silicon nanoclusters has been studied to get an insight into the excitation and de-excitation processes in silicon-rich oxynitride films. The thermal quenching of Er(3+) luminescence is elucidated by terms of decay time and effective excitation cross section. The temperature quenching of Er(3+) decay time demonstr...

The authors obtain, in the Laplace transform space, the exact analytic solution for the Green function and survival probabilities for the excited-state diffusion-influenced reversible geminate reaction, A*+B <==> C*+D, with two different lifetimes and in the presence of an added quenching process. This extends a previous investigation by Popov and Agmon [J. Chem. Phys. 117, 5770 (2002)] of the ...

The quenching by molecular oxygen of the fluorescence from a protoporphyrin IX adduct of horseradish peroxidase has been investigated using both intensity and time-resolved techniques. The bimolecular quenching rate constant determined for this process, as evaluated by the conventional Stern-Volmer analysis, was 2 x 10(8) M-1 s-1, among the lowest observed for protein systems. This result sugge...

Regulation of nonradiative dissipation of absorbed light energy in PSII is an indispensab]e process to ayoid photoinhibition in plants. To dissect molecular mechanisms of the regulation, we identified Arabidopsis mutants with reduced quenching of Chl fluorescence using a fiuorescence imaging system. By analyses of Chl fluorescence induction pattern in the light and quantum yield of both photosy...

In this paper the description of the simplest variant of conservative averaging method for partial differential (or integro-differential) equations in cylinder type domain is given. Different types of boundary conditions (both linear and non-linear) are considered. As application of the method the process of intensive steel quenching as the time inverse ill-posed problem for the hyperbolic heat...

Under selective excitation of the P0 level of the Pr3+ ion in YPO4, the emission spectra and fluorescence decay curves were measured at different concentrations and temperatures. The origin of the spectral line located at 16 318 cm−1 (612.8 nm) was discussed and attributed to the D2 → H4 transition. The process of concentration quenching for the D2 state was also studied. Using the Inokuti–Hira...

objective(s):cefixime (cfx), is a semi-synthetic third-generation oral cephalosporin antibiotic that is prescribed for the treatment of susceptible infections. there are some procedures for the determination of cfx in pharmaceutical formulations and biological samples. herein a spectrofluorimetric method was proposed for cfx determination based on the fluorescence quenching of terbium-danofloxa...

aqueous polymer quenchants are being used increasingly in steel heat treatment industries as a substitution for conventional quenchants. by adjusting the quench parameters of the polymeric media, it is possible to achieve desirable microstructure and mechanical properties in addition to reduction in distortion and cracking. in this work, polyalkylene glycol (pag) aqueous solution was used as th...

Quenching-partitioning-tempering (Q-P-T) heat treatment is a relatively novel approach to attain excellent ductility in high-strength steels. In the present work, microstructural evolution and mechanical properties of low carbon microalloyed advanced steel were systematically investigated after Q-P-T process. The was explored by employing X-ray diffraction, transmission electron microscopy scan...