Isomérisation photosensibilisée par des colorants et photoréduction de l'azobenzène en solution. II

1974 ◽  
Vol 52 (10) ◽  
pp. 1858-1867 ◽  
Author(s):  
Jacques Ronayette ◽  
René Arnaud ◽  
Jacques Lemaire
Keyword(s):  
Methylene Blue ◽  
Energy Transfer ◽  
Quantum Yield ◽  
Rose Bengal ◽  
Experimental Results ◽  
The Other ◽  
Eosin Y ◽  
Triplet States ◽  
Trans Form ◽  
Photochemical Isomerization

The photochemical isomerization of azobenzene in solution can be sensitized by dyes which have low-lying triplet states (rose Bengal, eosin Y, fluorescein, methylene blue) but cannot be inhibited by such compounds. The two triplet levels, Tβc and Tαc of the cis form are indistinguishable experimentally. On the other hand, the experimental results verify the existence of two triplet levels, Tβt and Tαt, with different properties, in the trans form. Population, by energy transfer, of the lower triplet, Tαt, leads to isomerization with a quantum yield near 0.5, whereas population of the triplet Tβt only rarely leads to isomerization (quantum yield about 0.03).The photoreduction of azobenzene in isopropanol also has been studied. Only the cis form is photoreducible and it is very difficult experimentally to determine whether this photoreduction can be sensitized.A Jablonski diagram of the two forms of azobenzene is presented to correlate these observations. [Journal translation]

Strahlungslose Übertragung der Anregungsenergie in lumineszierenden Lösungen verschiedener Konzentrationsverhältnisse von Donor zu Akzeptor / Non-Radiative Excitation Energy Transfer in Luminescent Solutions at Different Ratios of Donor to Acceptor Concentration

1973 ◽  
Vol 28 (10) ◽  
pp. 1697-1702 ◽  
Author(s):  
C. Bojarski ◽  
F. Burak ◽  
E. Grabowska
Keyword(s):  
Energy Transfer ◽  
Quantum Yield ◽  
Excitation Energy ◽  
Acta Phys ◽  
Rhodamine B ◽  
Excitation Energy Transfer ◽  
Experimental Results ◽  
Quantum Yields ◽  
Full Agreement ◽  
Acceptor Concentration

Photoluminescence (PL) quantum yields (η/η0) of Na-fluoresceine (donor) in dependence on phloxin (acceptor) concentration in glycerin-water solutions at ratios of donor to acceptor concentration CD/CA equal to 48.2, 14.5 and 2.4 have been measured.Similar measurements have been made on acriflavine (donor) and rhodamine B (acceptor) in methanol for CD/CA = 10 and 0.4. In all systems investigated it was found that the PL-yield η/η0 of the donor at a fixed value of CA is the smaller the bigger is the value of CD/CA. The experimental results have been compared with a theory (Z. Naturforsch. 25 a, 1760 [1970], Acta Phys. Hung. 30, 145 [1971]) describing concentrational changes of the PL-quantum yield. Full agreement of theory with experiment is found and the possibility of multi-step non-radiative excitation energy transfer from donor to acceptor has been proved.

On the Mechanism of Quenching by Amines: A New Method for Investigation of Interactions with Triplet States

1974 ◽  
Vol 52 (16) ◽  
pp. 2889-2893 ◽  
Author(s):  
Robert H. Young ◽  
D. Brewer ◽  
R. Kayser ◽  
R. Martin ◽  
D. Feriozi ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Charge Transfer ◽  
Singlet Oxygen ◽  
Rose Bengal ◽  
Rate Constants ◽  
Direct Method ◽  
Diffusion Limit ◽  
Triplet States ◽  
Novel Approach ◽  
Series Of Experiments

Rate constants for the quenching of singlet oxygen by a series of substituted N,N-dimethylanilines were obtained by a direct method employing a dye-laser. The Hammett ρ value obtained from the data (−1.71) suggests that a (partial) charge-transfer complex may be responsible for the quenching action. This rate data was combined with that obtained for the total quenching action on the sensitized photooxidation of 1,3-diphenylfuran. The quenching action on the photooxidation reaction is due to both the quenching of singlet oxygen and the quenching of the triplet state of the sensitizer (rose bengal or methylene blue). The combination of the data from each series of experiments resulted in rate constants of quenching of the triplet states of the sensitizers. A number of the N,N-dimethylanilines quenched the triplet states at the diffusion limit. Hammett ρ values (−1.86 for rose bengal and −4.19 for methylene blue) indicate that charge-transfer intermediates are probably responsible for the quenching action. This was confirmed by the observation of a transient intermediate assigned to the charge-transfer radical of methylene blue. The technique used here represents a novel approach to the investigation of triplet states.

Investigations of the Reversible Energy Transfer in Concentrated Dye Solutions

1987 ◽  
Vol 42 (12) ◽  
pp. 1451-1455 ◽  
Author(s):  
C. Bojarski ◽  
G. Żurkowska
Keyword(s):  
Energy Transfer ◽  
Theoretical Model ◽  
Quantum Yield ◽  
Rhodamine B ◽  
Fluorescence Quantum Yield ◽  
Rhodamine 6G ◽  
Experimental Results ◽  
High Concentration ◽  
Concentration Region ◽  
Dye Solutions

In the system rhodamine 6G (donor)/rhodamine B (acceptor) the reverse energy transfer considerably increases the donor fluorescence quantum yield, particularly in the high concentration region. These experimental results confirm a theoretical model with no adjustable parameters.

The Influence of Water Regime on the Performance of Aquatic Plants

1994 ◽  
Vol 29 (4) ◽  
pp. 127-132 ◽  
Author(s):  
Naomi Rea ◽  
George G. Ganf
Keyword(s):  
Deep Water ◽  
Aquatic Plants ◽  
Water Regime ◽  
Optimal Performance ◽  
Experimental Results ◽  
The Other ◽  
Full Potential ◽  
Influence Of Water ◽  
Emergent Species

Experimental results demonstrate bow small differences in depth and water regime have a significant affect on the accumulation and allocation of nutrients and biomass. Because the performance of aquatic plants depends on these factors, an understanding of their influence is essential to ensure that systems function at their full potential. The responses differed for two emergent species, indicating that within this morphological category, optimal performance will fall at different locations across a depth or water regime gradient. The performance of one species was unaffected by growth in mixture, whereas the other performed better in deep water and worse in shallow.

Mining discriminative patches for script identification in natural scene images

2021 ◽  
Vol 40 (1) ◽  
pp. 551-563
Author(s):  
Liqiong Lu ◽  
Dong Wu ◽  
Ziwei Tang ◽  
Yaohua Yi ◽  
Faliang Huang
Keyword(s):  
Neural Networks ◽  
Experimental Results ◽  
The Other ◽  
Natural Scene ◽  
Fixed Size ◽  
Script Identification ◽  
Aspect Ratios ◽  
Novel Approach ◽  
Public Datasets ◽  
Natural Scene Images

This paper focuses on script identification in natural scene images. Traditional CNNs (Convolution Neural Networks) cannot solve this problem perfectly for two reasons: one is the arbitrary aspect ratios of scene images which bring much difficulty to traditional CNNs with a fixed size image as the input. And the other is that some scripts with minor differences are easily confused because they share a subset of characters with the same shapes. We propose a novel approach combing Score CNN, Attention CNN and patches. Attention CNN is utilized to determine whether a patch is a discriminative patch and calculate the contribution weight of the discriminative patch to script identification of the whole image. Score CNN uses a discriminative patch as input and predict the score of each script type. Firstly patches with the same size are extracted from the scene images. Secondly these patches are used as inputs to Score CNN and Attention CNN to train two patch-level classifiers. Finally, the results of multiple discriminative patches extracted from the same image via the above two classifiers are fused to obtain the script type of this image. Using patches with the same size as inputs to CNN can avoid the problems caused by arbitrary aspect ratios of scene images. The trained classifiers can mine discriminative patches to accurately identify some confusing scripts. The experimental results show the good performance of our approach on four public datasets.

scholarly journals DV-DVFS: merging data variety and DVFS technique to manage the energy consumption of big data processing

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hossein Ahmadvand ◽  
Fouzhan Foroutan ◽  
Mahmood Fathy
Keyword(s):  
Big Data ◽  
Energy Consumption ◽  
Processing Time ◽  
Experimental Results ◽  
The Other ◽  
Data Sets ◽  
Multiple Sources ◽  
Evaluation Phase ◽  
Dynamic Voltage ◽  
Processing Resources

AbstractData variety is one of the most important features of Big Data. Data variety is the result of aggregating data from multiple sources and uneven distribution of data. This feature of Big Data causes high variation in the consumption of processing resources such as CPU consumption. This issue has been overlooked in previous works. To overcome the mentioned problem, in the present work, we used Dynamic Voltage and Frequency Scaling (DVFS) to reduce the energy consumption of computation. To this goal, we consider two types of deadlines as our constraint. Before applying the DVFS technique to computer nodes, we estimate the processing time and the frequency needed to meet the deadline. In the evaluation phase, we have used a set of data sets and applications. The experimental results show that our proposed approach surpasses the other scenarios in processing real datasets. Based on the experimental results in this paper, DV-DVFS can achieve up to 15% improvement in energy consumption.

Study of wave attenuation in concrete

1993 ◽  
Vol 8 (9) ◽  
pp. 2344-2353 ◽  
Author(s):  
J-M. Berthelot ◽  
Souda M. Ben ◽  
J.L. Robert
Keyword(s):  
Experimental Study ◽  
Plane Wave ◽  
Wave Attenuation ◽  
Plane Waves ◽  
Propagation Distance ◽  
Experimental Results ◽  
The Other ◽  
Wave Frequency ◽  
Concrete Composition ◽  
Analytical Expression

The experimental study of wave attenuation in concrete has been achieved in the case of the propagation of plane waves in concrete rods. Different mortars and concretes have been investigated. A transmitter transducer coupled to one of the ends of the concrete rod generates the propagation of a plane wave in the rod. The receiver transducer, similar to the previous one, is coupled to the other end of the rod. The experimental results lead to an analytical expression for wave attenuation as function of the concrete composition, the propagation distance, and the wave frequency.

Double dye cubic-sensitized solar cell based on Förster resonant energy transfer

RSC Advances ◽  
2015 ◽  
Vol 5 (13) ◽  
pp. 10026-10032 ◽  
Author(s):  
Wenxia Li ◽  
Jingbo Zhang ◽  
Yingyu Cao ◽  
Yuan Lin
Keyword(s):  
Energy Transfer ◽  
Spectral Response ◽  
Dye Sensitized Solar Cells ◽  
Eosin Y ◽  
Zno Thin Film ◽  
Resonant Energy ◽  
Dye Sensitized ◽  
Response Range ◽  
Resonant Energy Transfer ◽  
Sensitized Solar Cells

To extend the spectral response range of dye-sensitized solar cells through Förster resonant energy transfer, eosin Y and rhodamine B were chosen as an donor and a acceptor to cubic-sensitize nanocrystalline ZnO thin film.

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