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The estimation is obtained for the quenching time τl of the non-equilibrium orbital momentum of the electron that can be got after the excitation by the femtosecond optical pump. The quenching process of the l is supposed to be determined by the interaction of l with the crystal field and its deformations (phonons). The time τl is determined not only by the parameters of the crystal field but also by the speed of relaxation of the virtual phonon 1/τ(ω) with the frequency ω≈1/τl. Considering the frequency dependence of τ(ω) enlarges the estimated value of τl up to the microsecond scale. This value exceeds greatly the picoseconds times of the ultrafast magnetic dynamics (UMD) processes observed after the action of the femtosecond optical pump. This means that the results obtained in our work are not supposed to be compared with the experimental data on UMD. The presented description of the quenching of l is the solution of one of the auxiliary tasks that can be useful for construction of the UMD theory. [ABSTRACT FROM AUTHOR]

The series of Bi co-doped YPO : Eu nanophosphors were successfully synthesized by the slow evaporation method. Bi-doped and un-doped YPO : Eu phosphors were characterized by using powder X-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. Photoluminescence (PL) properties and decay time of phosphors were studied at room temperature. The YPO : Eu and Bi exhibit enhancement in PL intensity and quenched at 0.5 mol% of Bi ions. [ABSTRACT FROM AUTHOR]

The flame-retardant polylactic acid (PLA) has been prepared via mixing the flame retardant TGIC-DOPO derived from phosphaphenanthrene and triazine groups into matrix. The flame retardancy of TGIC-DOPO/PLA composites was characterized using the limiting oxygen index (LOI), vertical burning test (UL94), and cone calorimeter test. Results reveal that the 10%TGIC-DOPO/PLA composite obtained 26.1% of LOI and passed UL94 V-0 rating. The flame-retardant mechanism of PLA composites was characterized via thermogravimetric analysis (TGA), pyrolysis gas chromatography/mass spectroscopy, and TGA-Fourier transform infrared. It discloses that TGIC-DOPO promoted PLA decomposing and dripping early, and it also released the fragments with quenching and dilution effects. These actions of TGIC-DOPO contribute to reducing the burning intensity and extinguishing the fire on droplets, thus imposing better flame retardancy to PLA. When TGIC-DOPO was partly replaced by melamine cyanuric with dilution effect and hexa-phenoxy-cyclotriphosphazene with quenching effect in composites respectively, the results confirm that TGIC-DOPO utilize well-combination in dilution effect and quenching effect to flame retard PLA. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Terbium ion doped zinc aluminum phosphate (ZAP) glasses with composition (90− x )((90− y )P 2 O 5 –10Al 2 O 3 – y ZnO)– x Tb 2 O 3 ( x =0.5–9 in mol% and y =30, 35, 40 in mol%) have been prepared by melt quenching method, and the effects of the Tb 2 O 3 and ZnO content on the luminescence properties have been studied by photoluminescence spectroscopies. It was found that the green emission peaked at 544 nm is significantly enhanced under higher Tb 2 O 3 content, meanwhile the sensitization effect of ZnO content is confirmed from the enhanced main emission. The quenching effect attributed to the resonant energy transfer through the cross-relaxation mechanism is observed when Tb 2 O 3 concentration is beyond 2.5 mol% due to the fact that more Tb 3+ ions enhance the 4f→5d and 4f→4f electronic transitions through the dipole–dipole (d–d) interaction. Also, ZnO plays a role of the disperser to prevent non-radiative de-excitation process. A characteristic luminescence image of the (100− x )(60P 2 O 5 –10Al 2 O 3 –30ZnO)· x Tb 2 O 3 series glasses under UV excitation at 366 nm is presented for the first time, and the transition of luminescence suggests that the Tb 3+ -doped ZAP glasses are suitable for green and dual-color blue/green LED applications by modulation of Tb and ZnO composition. [ABSTRACT FROM AUTHOR]

In this paper, we report the production of C[C] with the highest specific radioactivity to date by improving of previously reported method. To avoid the loss of C, the porous carbon after adsorbing C labeled furan resin was sintered by 'Baking' method instead of heating at 1,000 °C in the electric furnace. As a result of this improvement, the specific radioactivity of the produced C[C] was found to be 0.958 MBq/mg (18.7 mCi/mmol). This is the highest specific radioactivity among those reported to date. [ABSTRACT FROM AUTHOR]

Highlights: [•] Determination of carbamate pesticides in dried lime tree flowers by EEM and PARAFAC. [•] Quenching effect and overlapping spectra are solved by three way techniques. [•] The second order property of PARAFAC decomposition is useful to solve problems in EEM. [•] Using PARAFAC to select the adequate dilution that minimizes the quenching effect. [•] A procedure to choose a D-optimal design for a multi-analyte standard addition method. [ABSTRACT FROM AUTHOR]

Highlights: [•] This work deals with the first attempt to study the effect of glutathione on chemiluminescence of peroxyoxalate. [•] The bimolecular rate constant of quenching of POCL system in the presence of an amino acid was estimated for the first time. [•] This system was applied successfully to determine glutathione in biological samples. [Copyright &y& Elsevier]