On the choice of proper average lifetime formula for an ensemble of emitters showing non-single exponential photoluminescence decay

2020 ◽  
Vol 32 (41) ◽  
pp. 415902
Author(s):  
G Zatryb ◽  
M M Klak
Keyword(s):  
Average Lifetime ◽  
Photoluminescence Decay ◽  
Single Exponential

A Deconvolution Technique for Determining the Intrinsic Fluorescence Decay Lifetimes of Crude Oils

1988 ◽  
Vol 42 (3) ◽  
pp. 406-410 ◽  
Author(s):  
M. F. Quinn ◽  
S. Joubian ◽  
F. Al-Bahrani ◽  
S. Al-Aruri ◽  
Oussama Alameddine
Keyword(s):  
Fourier Transform ◽  
Impulse Response ◽  
Exponential Decay ◽  
Fluorescence Decay ◽  
Average Lifetime ◽  
Nitrogen Laser ◽  
Alternative Approach ◽  
Deconvolution Technique ◽  
The Fourier Transform ◽  
Single Exponential

A simple deconvolution procedure using FT was developed for determining the average lifetime of samples excited by a nitrogen laser pumped dye laser operating at 428 nm. To overcome the noise limitations imposed by including higher frequency harmonics in the analysis, we used an alternative approach. This approach relied on taking the Fourier transform at 21 subharmonic frequencies and using an appropriate weighting procedure in the calculation of amplitude and lifetime of the sample impulse response. A single exponential decay was assumed.

scholarly journals Elimination of Chromosome Aberrations from Human Lymphocytes

Blood ◽  
1966 ◽  
Vol 27 (5) ◽  
pp. 706-714 ◽  
Author(s):  
AMOS NORMAN ◽  
M. S. SASAKI ◽  
R. E. OTTOMAN ◽  
A. G. FINGERHUT
Keyword(s):  
Radiation Therapy ◽  
Chromosome Aberrations ◽  
Human Lymphocytes ◽  
Average Lifetime ◽  
Structural Aberrations ◽  
Chromosome Fragments ◽  
Stable Frequency ◽  
Normal Women ◽  
Single Exponential

Abstract The frequency of chromosome aberrations in the lymphocytes of 36 hematologically normal women who had received radiation therapy for cervical carcinoma was measured. The decrease with time in the frequency of cells with acentric fragments, of cells with a single dicentric, and of quasidiploid cells can each be represented by a single exponential with an average lifetime, respectively, of 530 ± 64 days, 788 ± 98 days, and 5.55 ± 1.23 x 103 days. Aneuploid cells fall into two classes: One contains no chromosomes with structural aberrations and shows a stable frequency of about 5.8 per cent; the other contains chromosomes with structural aberrations and is eliminated at the same rate as cells with acentric chromosome fragments. The distribution of dicentrics among the lymphocytes at the end of the radiation therapy period is similar to that shown by a population of lymphocytes exposed in vitro to a single dose of about 300 rads.

Statistical approach for describing failures and lifetimes of water mains

1998 ◽  
Vol 38 (6) ◽  
pp. 209-217 ◽  
Author(s):  
Jianhua Lei ◽  
Sveinung Sægrov
Keyword(s):  
Data Base ◽  
Ductile Iron ◽  
Counting Process ◽  
Statistical Approach ◽  
Process Models ◽  
Average Lifetime ◽  
Maintenance Practice ◽  
Water Mains ◽  
Near Future

This paper demonstrates the statistical approach for describing failures and lifetimes of water mains. The statistical approach is based on pipe inventory data and the maintenance data registered in the data base. The approach consists of data pre-processing and statistical analysis. Two classes of statistical models are applied, namely counting process models and lifetime models. With lifetime models, one can estimate the probability which a pipe will fail within a time horizon. With counting process models one can see the deteriorating (or improving) trend in time of a group of “identical” pipes and their rates of occurrence of failure (ROCOF). The case study with the data base from Trondheim municipality (Norway) demonstrates the applicability of the statistical approach and leads to the following results: 1). In the past 20 years, Trondheim municipality has experienced approximately 250 to 300 failures per year. However, the number of failures per year will significantly increase in the near future unless better maintenance practice is implemented now. 2). Unprotected ductile iron pipes have a higher probability of failures than other materials. The average lifetime of unprotected ductile iron pipes is approximately 30 to 40 years shorter than the lifetime of a cast iron pipe. 3). Pipes installed 1963 and 1975 are most likely to fail in the future; 4) The age of a pipe does not play a significant role for the remaining lifetime of the pipe; 5). After 2 to 3 failures, a pipe enters a fast-failure stage (i.e., frequent multiple between failures).

Myocardial blood flow determined with krypton 85 in unanesthetized dogs

1962 ◽  
Vol 203 (1) ◽  
pp. 122-124 ◽  
Author(s):  
J. A. Herd ◽  
M. Hollenberg ◽  
G. D. Thorburn ◽  
H. H. Kopald ◽  
A. C. Barger
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Myocardial Blood Flow ◽  
Exponential Function ◽  
Scintillation Detector ◽  
Left Ventricular ◽  
Blood Flows ◽  
Single Exponential Function ◽  
Single Exponential ◽  
Rapid Measurements

Serial, rapid measurements of left ventricular myocardial blood flow in trained, unanesthetized dogs have been made by injecting krypton 85 through chronically implanted coronary artery catheters and counting with an external scintillation detector. Precordial radioactivity declined as a single exponential function during the first 2 min after injection, suggesting a single rate of myocardial blood flow. Simultaneous estimations with Kr85 and blood flowmeters in acute experiments established the accuracy and reproducibility of the technique. Myocardial blood flows between 40 and 55 ml/100 g/min were observed repeatedly in three well-trained, unanesthetized dogs in the basal state.

scholarly journals Research of Fluorescent Properties of a New Type of Phosphor with Mn2+-Doped Ca2SiO4

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2788
Author(s):  
Xiaozhou Fan ◽  
Wenqi Zhang ◽  
Fangcheng Lü ◽  
Yueyi Sui ◽  
Jiaxue Wang ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Green Emission ◽  
Response Speed ◽  
Sintered Sample ◽  
Solid State Reaction Method ◽  
Average Lifetime ◽  
Diffraction Spectrum ◽  
Fluorescent Properties ◽  
Fluorescent Material ◽  
New Type

Fluorescent optical fiber temperature sensors have attracted extensive attention due to their strong anti-electromagnetic interference ability, good high-voltage insulation performance, and fast response speed. The fluorescent material of the sensor probe directly determines the temperature measurement effect. In this paper, a new type of fluorescent material with a Mn2+-doped Ca2SiO4 phosphor (CSO:Mn2+) is synthesized via the solid-state reaction method at 1450 °C. The X-ray diffraction spectrum shows that the sintered sample has a pure phase structure, although the diffraction peaks show a slight shift when dopants are added. The temperature dependence of the fluorescence intensity and lifetime in the range from 290 to 450 K is explored with the help of a fluorescence spectrometer. Green emission bands peaking at 475 and 550 nm from Mn2+ are observed in the fluorescence spectra, and the intensity of emitted light decreases as the temperature rises. The average lifetime of CSO:Mn2+ is 17 ms, which is much higher than the commonly used fluorescent materials on the market. The fluorescence lifetime decreases with increasing temperature and shows a good linear relationship within a certain temperature range. The research results are of great significance to the development of a new generation of fluorescence sensors.

scholarly journals Linear Kernels and Single-Exponential Algorithms Via Protrusion Decompositions

2016 ◽  
Vol 12 (2) ◽  
pp. 1-41 ◽  
Author(s):  
Eun Jung Kim ◽  
Alexander Langer ◽  
Christophe Paul ◽  
Felix Reidl ◽  
Peter Rossmanith ◽  
...  
Keyword(s):  
Single Exponential

Trap-State-Induced Becquerel Type of Photoluminescence Decay in DPA-Activated Silicon Nanocrystals

2021 ◽  
Vol 125 (3) ◽  
pp. 2055-2063
Author(s):  
K. Kůsová ◽  
T. Popelář ◽  
I. Pelant ◽  
G. Morselli ◽  
S. Angeloni ◽  
...  
Keyword(s):  
Silicon Nanocrystals ◽  
Trap State ◽  
Photoluminescence Decay

scholarly journals Optimal Preventive Maintenance of Wind Turbine Components with Imperfect Continuous Condition Monitoring

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3801 ◽  
Author(s):  
Ahmed Raza ◽  
Vladimir Ulansky
Keyword(s):  
Wind Turbine ◽  
Condition Monitoring ◽  
Preventive Maintenance ◽  
False Negative ◽  
Maintenance Cost ◽  
Arbitrary Distribution ◽  
Average Lifetime ◽  
True Negative ◽  
Degradation Failure ◽  
Lifetime Maintenance

Among the different maintenance techniques applied to wind turbine (WT) components, online condition monitoring is probably the most promising technique. The maintenance models based on online condition monitoring have been examined in many studies. However, no study has considered preventive maintenance models with incorporated probabilities of correct and incorrect decisions made during continuous condition monitoring. This article presents a mathematical model of preventive maintenance, with imperfect continuous condition monitoring of the WT components. For the first time, the article introduces generalized expressions for calculating the interval probabilities of false positive, true positive, false negative, and true negative when continuously monitoring the condition of a WT component. Mathematical equations that allow for calculating the expected cost of maintenance per unit of time and the average lifetime maintenance cost are derived for an arbitrary distribution of time to degradation failure. A numerical example of WT blades maintenance illustrates that preventive maintenance with online condition monitoring reduces the average lifetime maintenance cost by 11.8 times, as compared to corrective maintenance, and by at least 4.2 and 2.6 times, compared with predetermined preventive maintenance for low and high crack initiation rates, respectively.

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