Role of various moving walls on energy transfer rates via heat flow visualization during mixed convection in square cavities

Energy ◽  
2015 ◽  
Vol 82 ◽  
pp. 1-22 ◽  
Author(s):  
Monisha Roy ◽  
S. Roy ◽  
Tanmay Basak
Keyword(s):  
Energy Transfer ◽  
Heat Flow ◽  
Mixed Convection ◽  
Flow Visualization ◽  
Transfer Rates

scholarly journals Diffusion Enhanced Upconversion in Organic Systems

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
A. Monguzzi ◽  
R. Tubino ◽  
F. Meinardi
Keyword(s):  
Energy Transfer ◽  
Molecular Diffusion ◽  
Blue Emission ◽  
Fast Diffusion ◽  
Triplet States ◽  
Excitation Light ◽  
Transfer Rates ◽  
Organic Systems ◽  
Emission Yield

The upconverted fluorescence generation in a solution of multicomponent organic systems has been studied as a function of the temperature to investigate the role of resonant energy transfer processes and of the molecular diffusion on the overall emission yield. The strong blue emission observed exciting the samples at 532 nm derives from a bimolecular triplet-triplet annihilation between 9,10 diphenylanthracene molecules, which produces singlet excited states from which the higher energy emission takes place. Diphenylanthracene excited triplet states are populated by energy transfer from a phosphorescent donor (Pt(II)octaethylporphyrin) which acts as excitation light harvesting. At low temperature, the experimental data on the efficiency of the transfer have been interpreted in the frame of a Dexter energy transfer in the Perrin approximation. At room temperature, the fast diffusion of the molecules has been found to be the main factor which affects the energy transfer rates and the overall photon upconversion efficiency.

scholarly journals The role of Nd3+ in the population inversion between 1G4 and 3H6 states of Tm3+ in Yb:Nd:Tm:YLF crystal 1 DOI: 10.5585/exacta.v5i1.1035

Exacta ◽  
2008 ◽  
Vol 5 (1) ◽  
Author(s):  
André Felipe Henriques Librantz ◽  
Lilia Coronato Courrol ◽  
Laércio Gomes ◽  
Sonia Lícia Baldochi ◽  
Izilda Marcia Ranieri
Keyword(s):  
Energy Transfer ◽  
Population Inversion ◽  
Upconversion Emission ◽  
Rate Equations ◽  
Kutta Method ◽  
Pumping Rate ◽  
Transfer Rates ◽  
Runge Kutta Method ◽  
Rate Threshold

In this paper, we present the energy transfer rates of YLF:Yb:Tm:Nd system, identifying the most important processes that lead to the thulium blue upconversion emission under excitation around 792 nm. The calculation of the rate equations system based on numerical method using Runge-Kutta method was employed for analyzing the population inversion between 1G4 and 3H4 states of Tm3+. Population inversion was achieved only in Yb:Nd:Tm doped YLF crystal, which exhibits a pumping rate threshold of 620 s-1. The Nd3+ absorption near 792 nm is very important because the excitation is rapidly transferred to Yb3+, that also interacts with Tm3+.

scholarly journals The role of Nd3+ in the population inversion between 1G4 and 3H6 states of Tm3+ in Yb:Nd:Tm:YLF crystal

Exacta ◽  
2008 ◽  
Vol 5 (1) ◽  
Author(s):  
André Felipe Henriques Librantz ◽  
Lilia Coronato Courrol ◽  
Laércio Gomes ◽  
Sonia Lícia Baldochi ◽  
Izilda Marcia Ranieri
Keyword(s):  
Energy Transfer ◽  
Population Inversion ◽  
Upconversion Emission ◽  
Rate Equations ◽  
Kutta Method ◽  
Pumping Rate ◽  
Transfer Rates ◽  
Runge Kutta Method ◽  
Rate Threshold

In this paper, we present the energy transfer rates of YLF:Yb:Tm:Nd system, identifying the most important processes that lead to the thulium blue upconversion emission under excitation around 792 nm. The calculation of the rate equations system based on numerical method using Runge-Kutta method was employed for analyzing the population inversion between 1G4 and 3H4 states of Tm3+. Population inversion was achieved only in Yb:Nd:Tm doped YLF crystal, which exhibits a pumping rate threshold of 620 s-1. The Nd3+ absorption near 792 nm is very important because the excitation is rapidly transferred to Yb3+, that also interacts with Tm3+.

Adiabatic large polarons in anisotropic molecular crystals

2011 ◽  
Vol 35 (1) ◽  
pp. 15-27
Author(s):  
Zoran Ivić ◽  
Željko Pržulj
Keyword(s):  
Energy Transfer ◽  
Effective Mass ◽  
Molecular Crystals ◽  
Single Chain ◽  
Proper Understanding ◽  
One Dimensional ◽  
Interchain Coupling ◽  
Large Polaron ◽  
The One

Adiabatic large polarons in anisotropic molecular crystals We study the large polaron whose motion is confined to a single chain in a system composed of the collection of parallel molecular chains embedded in threedimensional lattice. It is found that the interchain coupling has a significant impact on the large polaron characteristics. In particular, its radius is quite larger while its effective mass is considerably lighter than that estimated within the one-dimensional models. We believe that our findings should be taken into account for the proper understanding of the possible role of large polarons in the charge and energy transfer in quasi-one-dimensional substances.

Origin of the Red Sites and Energy Transfer Rates in Single MEH-PPV Chains at Low Temperature

ChemPhysChem ◽  
2011 ◽  
Vol 12 (8) ◽  
pp. 1499-1508 ◽  
Author(s):  
Florian A. Feist ◽  
Martin F. Zickler ◽  
Thomas Basché
Keyword(s):  
Energy Transfer ◽  
Low Temperature ◽  
Transfer Rates
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