Luminescent materials often suffer from thermal quenching (TQ), limiting the continuation of their applications under high temperatures up to 473 K. The formation defect levels could suppress TQ, but rational synthesis and deep understanding multiple defects-regulated luminescent working in such a wide temperature range still remain challenging. Here, we prepare negative (NTQ) phosphor LiTaO3 :...

The heat capacities of annealed and quenched samples of Lio.osZno.poFea.as04 and of quenched ZnFqO, have been determined over the range .5-350°K. Addition of lithium to zinc ferrite lowers the temperature of the co-operative thermal anomaly associated with antiferromagnetic ordering transition in accord with theory, and quenching of either material results in nearly complete disappearance of th...

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...

Large grain polycrystalline silicon wafers have been subjected to post~annealing (900 °C/45 ruin) after POCI3 pre-diffusion at different temperatures. For the first time we have investigated the effect of the furnace starting and quenching temperature on the gettering efficiency. The optimisation of thermal cycle parameters include the determination of the best combination of starting temperatu...

We propose a rate process model for describing photochemical damage to retinal cells by short wavelength laser exposures. The rate equation for photochemical damage contains a positive rate that is temperature independent, and a negative (quenching) rate that is temperature dependent. Using the traditional Arrhenius integral to describe thermal damage, we derive damage threshold doses for both ...

The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies...

A series of Mg2-xAl4Si5O18:xDy(3+) (0 ≤x≤ 0.18) samples were synthesized, for the first time, by a solid state method both in a reducing atmosphere and in air. XRD, diffuse reflectance spectra, excitation spectra, emission spectra, decay times and thermal quenching were used to investigate the structure, photoluminescence, energy transfer and thermal properties. The results show that Mg2Al4Si5O...

transparent glasses in a system of li2o-mgo-sio2-al2o3-fchemical constituents were prepared by melt quenching method. in the fabrication of nanocrystal glass-ceramics, controlled nucleation and subsequent crystal growth were necessary to avoid loss of transparency. it was therefore important to understand thermal properties and crystallization kinetics of the glass ceramics. the crystallization...

the quenching of quinine fluorescence intensity in the presence of some anions in aqueous solution at ambient temperature has been investigated. the quenching is found to be collisional or dynamical in nature. this study reveals the order of two groups of quencher: nai > nabr > nacl > naf and k2cr2o7 > kmno4 >na2so4 > naclo3. increasing anion size in the both groups leads to an  increase in the...