Journal articles: 'Lifetime'

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Omar, Moien A. "The Significance of Considering Battery Service-Lifetime for Correctly Sizing Hybrid PV–Diesel Energy Systems." Energies 17, no. 1 (December 23, 2023): 103. http://dx.doi.org/10.3390/en17010103.

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This study emphasizes how crucial it is to consider battery service lifetime when determining the optimal battery size in PV–diesel hybrid systems. It investigates how battery size influences the evaluation of hybrid systems and their lifetime due to battery cycling. Unlike previous research that relies on assumed battery lifetimes, this study delves into the tangible impact of battery cycling, revealing the intricate relationship between battery size, cycling behavior, and service lifetime. Utilizing HOMER Pro version 3.14.2 software, a case study assessed three battery capacities (300 Ah, 800 Ah, and 1000 Ah) in a hybrid PV system catering to a 24 kWh daily demand. Across varying assumed lifetimes (5, 10, and 20 years), the study found that a 300 Ah battery was the most feasible under a 5-year assumed battery lifetime. However, for 10-year and 20-year battery lifetimes, the 800 Ah system emerged as the optimal choice, emphasizing the influence of assumed lifetime on determining the optimal battery size. Throughput battery lifetime analysis estimated service lifetimes of 4.9, 10.96, and 13.64 years for the 300 Ah, 800 Ah, and 1000 Ah batteries, respectively. Notably, smaller-rated batteries exhibited shorter estimated service lifetimes linked to usage patterns. Among the systems assuming a 20-year calendar lifetime, the optimal 800 Ah system, with a service lifetime of 10.96 years, yielded an energy cost of 0.312 USD/kWh, annual costs of USD 2736.5, and a total cost of USD 37,450. Considering service lifetime, the 800 Ah system emerged as optimal, contrasting the initially favored 300 Ah system under a 5-year assumed lifetime. This underscores the crucial significance of comprehending and integrating service lifetime considerations to optimize the economic feasibility of PV hybrid systems.

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Chung, Gil Yong, Mark J. Loboda, M. J. Marninella, D. K. Schroder, Tamara Isaacs-Smith, and John R. Williams. "Carrier Generation Lifetime in 4H-SiC Epitaxial Wafers." Materials Science Forum 615-617 (March 2009): 283–86. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.283.

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The pulsed MOS-C (Metal Oxide Semiconductor-Capacitor) technique was used to measure generation lifetimes in 4H-SiC epitaxial wafers. The ratio of generation to recombination lifetime has been investigated to understand the dominant defect for generation lifetime. The EH6/7 defect level is considered to limit generation lifetime and field enhanced emission is proposed to explain extremely large variation of generation lifetime in a small area. Generation lifetime is limited by dislocations when they are above a threshold density of about 106cm-2. Generation lifetimes measured on 4 and 8 degree off-cut angle epi-substrates are very comparable.

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Chung, Gil Yong, Mark J. Loboda, Mike F. MacMillan, Jian Wei Wan, and Darren M. Hansen. "Carrier Lifetime Analysis by Microwave Photoconductive Decay (μ-PCD) for 4H SiC Epitaxial Wafers." Materials Science Forum 556-557 (September 2007): 323–26. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.323.

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Excess carrier lifetimes in 4H SiC epitaxial wafers were characterized by microwave photoconductive decay (o/PCD). The measured decay compromised of surface and bulk recombination curves have fast and slow components. Measured lifetimes are not changed with various surface passivation techniques. High resolution lifetime maps show good correlation with stress birefringence images and lower lifetime around extended material defects like grainboundaries, defect clusters, edge defects and polytype switching bands. Chlorosilane based CVD epiwafers show higher bulk lifetime values than standard silane based CVD materials due to less bulk lifetime defect density.

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Brismar, H., O. Trepte, and B. Ulfhake. "Spectra and fluorescence lifetimes of lissamine rhodamine, tetramethylrhodamine isothiocyanate, texas red, and cyanine 3.18 fluorophores: influences of some environmental factors recorded with a confocal laser scanning microscope." Journal of Histochemistry & Cytochemistry 43, no. 7 (July 1995): 699–707. http://dx.doi.org/10.1177/43.7.7608524.

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We report on the spectra and fluorescence lifetimes of four commonly used fluorophores: lissamine rhodamine (LRSC); tetramethyl rhodamine isothiocyanate (TRITC); Texas Red; and cyanine 3.18 (Cy-3). Fluorescence lifetime recordings revealed that these spectrally overlapping fluorophores can be individually detected by their lifetimes, indicating that at least four fluorophores can be individually identified in discrete tissue domains by confocal microscopy. A further advantage of lifetime recordings is that fluorophores that emit light within the same wavelength band can be used and chromatic aberrations are therefore circumvented, thereby improving the spatial accuracy in imaging of multiple fluorophores. Low and high pH, respectively, tended to influence fluorophore emission spectra and fluorescence lifetime. IgG conjugation of the fluorophores tended to shift the spectra towards longer wavelengths and to change the fluorescence lifetimes. The IgG-conjugated form of the fluorophores may, when applied to tissue specimens, change the emission spectrum and lifetime. In addition, different tissue embedding procedures may influence fluorescence lifetime. These observations emphasize the importance of spectral and lifetime characterization of fluorescent probes within the chemical context in which they will be used experimentally. Changes in spectra and fluorescence lifetimes may be a useful tool to gain information about the chemical environment of the fluorophores.

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Thomas, T. D., and T. X. Carroll. "Inner-shell lifetimes from lifetime-vibrational interference." Chemical Physics Letters 185, no. 1-2 (October 1991): 31–35. http://dx.doi.org/10.1016/0009-2614(91)80134-j.

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Waters, P. Dean, and David H. Burns. "Optimized Gated Detection for Lifetime Measurement over a Wide Range of Single Exponential Decays." Applied Spectroscopy 47, no. 1 (January 1993): 111–15. http://dx.doi.org/10.1366/0003702934048622.

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Optimal estimation parameters are determined for the rapid lifetime determination technique (RLD) of fitting an exponential model to luminescence decay data that exhibit a wide range of lifetimes. Optimization of the lifetime estimate by this technique depends on only two parameters—period of integration and separation between the periods of integration. Luminescence quenching experiments produce a range of decay lifetimes. Selection of a fixed set of measuring parameters to determine lifetime throughout the entire range can simplify instrumentation and result in enhanced computation speed. The measuring parameters must be optimized to yield the best estimation of each lifetime in the range. The errors in measured lifetime for the RLD technique are investigated for a wide range of luminescence decays. Optimal separation and periods of integration for the modified RLD technique are found by modeling a set of simulated decay data with different lifetimes. Results from the simulation are then compared to similar measurements of oxygen-quenched luminescence decay. Agreement between simulation and quenching data is good.

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Hoffmann, L., C. M. Hoppe, R. Müller, G. S. Dutton, J. C. Gille, S. Griessbach, A. Jones, et al. "Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies." Atmospheric Chemistry and Physics Discussions 14, no. 11 (June 25, 2014): 16865–906. http://dx.doi.org/10.5194/acpd-14-16865-2014.

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Abstract. Chlorofluorocarbons (CFCs) play a key role in stratospheric ozone loss and are strong infrared absorbers that contribute to global warming. The stratospheric lifetimes of CFCs are a measure of their global loss rates that are needed to determine global warming and ozone depletion potentials. We applied the tracer-tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11) and CF2Cl2 (CFC-12). We present estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 yr for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), the HIgh Resolution Dynamics Limb Sounder (HIRDLS), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We found a CFC-11/CFC-12 lifetime ratio of 0.47±0.08 and a CFC-12 lifetime of 111(96–132) yr for ACE-FTS, a ratio of 0.46±0.07 and a lifetime of 112(97–133) yr for HIRDLS, and a ratio of 0.46±0.08 and a lifetime of 112(96–135) yr for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.47±0.04 and the CFC-12 lifetime estimate is 112(102–123) yr. These results agree with the recent Stratosphere-troposphere Processes And their Role in Climate (SPARC) reassessment, which recommends lifetimes of 52(43–67) yr and 102(88–122) yr, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled model we found a CFC-11/CFC-12 lifetime ratio of 0.48±0.07 and a CFC-12 lifetime of 110(95–129) yr, based on a ten-year perpetual run. Closely reproducing the satellite observations, the new model system will likely become a useful tool to assess the impact of advective transport, mixing, and photochemistry as well as climatological variability on the stratospheric lifetimes of long-lived tracers.

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Hoffmann, L., C. M. Hoppe, R. Müller, G. S. Dutton, J. C. Gille, S. Griessbach, A. Jones, et al. "Stratospheric lifetime ratio of CFC-11 and CFC-12 from satellite and model climatologies." Atmospheric Chemistry and Physics 14, no. 22 (November 27, 2014): 12479–97. http://dx.doi.org/10.5194/acp-14-12479-2014.

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Abstract. Chlorofluorocarbons (CFCs) play a key role in stratospheric ozone loss and are strong infrared absorbers that contribute to global warming. The stratospheric lifetimes of CFCs are a measure of their stratospheric loss rates that are needed to determine global warming and ozone depletion potentials. We applied the tracer–tracer correlation approach to zonal mean climatologies from satellite measurements and model data to assess the lifetimes of CFCl3 (CFC-11) and CF2Cl2 (CFC-12). We present estimates of the CFC-11/CFC-12 lifetime ratio and the absolute lifetime of CFC-12, based on a reference lifetime of 52 years for CFC-11. We analyzed climatologies from three satellite missions, the Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS), the HIgh Resolution Dynamics Limb Sounder (HIRDLS), and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). We found a CFC-11/CFC-12 lifetime ratio of 0.47±0.08 and a CFC-12 lifetime of 112(96–133) years for ACE-FTS, a ratio of 0.46±0.07 and a lifetime of 113(97–134) years for HIRDLS, and a ratio of 0.46±0.08 and a lifetime of 114(98–136) years for MIPAS. The error-weighted, combined CFC-11/CFC-12 lifetime ratio is 0.46±0.04 and the CFC-12 lifetime estimate is 113(103–124) years. These results agree with the recent Stratosphere-troposphere Processes And their Role in Climate (SPARC) reassessment, which recommends lifetimes of 52(43–67) years and 102(88–122) years, respectively. Having smaller uncertainties than the results from other recent studies, our estimates can help to better constrain CFC-11 and CFC-12 lifetime recommendations in future scientific studies and assessments. Furthermore, the satellite observations were used to validate first simulation results from a new coupled model system, which integrates a Lagrangian chemistry transport model into a climate model. For the coupled model we found a CFC-11/CFC-12 lifetime ratio of 0.48±0.07 and a CFC-12 lifetime of 110(95–129) years, based on a 10-year perpetual run. Closely reproducing the satellite observations, the new model system will likely become a useful tool to assess the impact of advective transport, mixing, and photochemistry as well as climatological variability on the stratospheric lifetimes of long-lived tracers.

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Guo, Wei Feng, Xiang Lei Chen, Huai Jiang Du, Hui Min Weng, and Bang Jiao Ye. "Positron Annihilation in Carbon Nanotubes." Materials Science Forum 607 (November 2008): 198–200. http://dx.doi.org/10.4028/www.scientific.net/msf.607.198.

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Positron annihilation lifetime spectra have been measured in carbon nanotubes being pressed as a function of pressure up to 1536MPa. In addition, positron lifetime experiments for carbon nanotubes in vacuum, nitrogen and air have been performed respectively. Lifetimes have been obtained using LIFETIME program. The results display a single-component positron annihilation lifetime. Positron lifetime for carbon nanotubes decreases as the pressure increases, but lifetime is basically consistent after the pressure of 960MPa. Positron annihilation lifetime for carbon nanotubes in air is the shortest whereas the lifetime in vacuum the longest. We conclude that a positron annihilates with an electron on the external surface of carbon nanotubes.

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Sodemann, Harald. "Beyond Turnover Time: Constraining the Lifetime Distribution of Water Vapor from Simple and Complex Approaches." Journal of the Atmospheric Sciences 77, no. 2 (January 10, 2020): 413–33. http://dx.doi.org/10.1175/jas-d-18-0336.1.

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Abstract The time water vapor spends in the atmosphere from evaporation to precipitation, termed here the water vapor lifetime, is of fundamental relevance for characterizing the water cycle, for the turnover of mass and energy, causes of precipitation extremes, and the recycling of precipitation over land. While the global average lifetime of water vapor is commonly considered as about 8–10 days, recent work indicates that the distribution of water vapor lifetimes is highly skewed, and that a large part of the water vapor could have average lifetimes of about 4–5 days. Besides calling for scrutiny of these new estimates, these findings also prompt an investigation of the factors shaping the distribution of the lifetime of water vapor. Using idealized setups and reanalysis data, I explore the influence of heterogeneity and nonstationarity on water vapor age and lifetime. The combination of nonstationarity and heterogeneity allows for short and long local lifetimes and water vapor ages, while maintaining the global average mass balance and corresponding mean water vapor lifetime. A plausibility argument based on humidity-weighted winds suggests that median lifetimes of 4–5 days are more consistent with weather system patterns in the extratropics. I propose that the median of the lifetime is more representative, since its mean value is affected by uncertainty originating from a long, thin tail. To more comprehensively understand the water vapor lifetime, methods will need to report the full lifetime distribution. Simulations with artificial water tracers could thereby provide the framework to compare different methods consistently in the future, while stable water isotopes could serve as an observational constraint.

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Saish Nilesh Joshi. "Orbital Lifetime Estimation of Rocket Bodies in Eccentric Low Earth, Low Inclination Orbits." Acceleron Aerospace Journal 3, no. 6 (November 30, 2024): 613–23. https://doi.org/10.61359/11.2106-2463.

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The dense population of Low Earth Orbit (LEO) due to frequent launches necessitates precise knowledge of the orbital lifetime of rocket bodies in this region. This study focuses on estimating the orbital lifetime of rocket bodies in eccentric, low-inclination LEO. Using the open-source software General Mission Analysis Tool (GMAT), the orbital lifetimes of rocket bodies with masses of 1000 kg, 1200 kg, and 1400 kg were calculated for altitudes ranging from 250 km to 500 km and inclinations of 0˚, 10˚, and 20˚. The orbital lifetimes of the defunct rocket bodies ranged from 3 to 832 days. GMAT-derived orbital lifetimes were compared with those obtained using Systems Tool Kit (STK). A subsequent 2D interpolation code was developed to interpolate the lifetime for a user-provided configuration of mass and orbital altitude. The Python code interpolated the orbital lifetimes for the given configurations with a maximum error of 5% compared to the GMAT-simulated lifetime values. This approach provides essential data for assessing post-mission disposal plans for rocket bodies and ensuring alignment with the Inter-Agency Space Debris Coordination Committee (IADC) 25-year guideline. Key findings reveal that the orbital lifetime of a rocket body increases with inclination. Additionally, it was observed that the orbital lifetime increases with mass due to slower orbital decay.

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Miyazawa, Tetsuya, Masahiko Ito, and Hidekazu Tsuchida. "Evaluation of Long Carrier Lifetimes in Very Thick 4H-SiC Epilayers." Materials Science Forum 679-680 (March 2011): 197–200. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.197.

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We investigate the carrier lifetimes in very thick 4H-SiC epilayers (~250 μm) by means of time-resolved photoluminescence and microwave photoconductive decay. Both the minority carrier lifetime and the high injection lifetime are found to reach 18.5 μs by applying the carbon implantation/annealing method to the as-grown epilayers. We also study the epilayer thickness dependence of the carrier lifetime by successive experiments involving lifetime measurement and polishing. Based on the relationships between epilayer thickness and carrier lifetime, the bulk carrier lifetime and the hole diffusion constant are discussed.

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Chen, Xiang Lei, Wei Feng Guo, Huai Jiang Du, Hui Min Weng, and Bang Jiao Ye. "The Calculation of Positron Lifetime in Ni₃Al Alloy." Materials Science Forum 607 (November 2008): 146–48. http://dx.doi.org/10.4028/www.scientific.net/msf.607.146.

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Superposed-neutral-atom model and the finite-difference method (SNA-FD) are used to calculate the positron lifetime of different sizes and types of vacancy clusters in Ni3Al alloy. The calculated positron bulk lifetime in Ni3Al agrees well with the experimental results mentioned in literatures. The positron lifetimes of vacancy clusters with the same amount of vacancy but different components are also calculated. The results show that the positron lifetime is different when its components are different. The positron lifetimes of vacancy clusters with a single element but different sizes are also calculated. The result shows that the positron lifetime is almost a constant when its component is only Al vacancy, but the positron lifetime will increase at first and trend to be a constant when its component is only Ni vacancy.

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Sun, Jian Wu, Satoshi Kamiyama, Rositza Yakimova, and Mikael Syväjärvi. "Effect of Surface and Interface Recombination on Carrier Lifetime in 6H-SiC Layers." Materials Science Forum 740-742 (January 2013): 490–93. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.490.

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Carrier lifetimes in 6H-SiC epilayers were investigated by using numerical simulations and micro-wave photoconductivity decay measurements. The measured carrier lifetimes were significantly increasing with an increased thickness up to 200 μm while it stays almost constant in layers thicker than 200 μm. From a comparison of the simulation and experimental results, we found that if the bulk lifetime in 6H-SiC is around a few microseconds, both the surface recombination and interface recombination influence the carrier lifetime in layers with thickness less than 200 μm while only the surface recombination determines the carrier lifetime in layers with thickness more than 200 μm. In samples with varying thicknesses, a bulk lifetime = 2.93 μs and carrier diffusion coefficient D= 2.87 cm2/s were derived from the linear fitting of reciprocal lifetime vs reciprocal square thickness.

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KUIK, D. J., C. POELMA, and J. WESTERWEEL. "Quantitative measurement of the lifetime of localized turbulence in pipe flow." Journal of Fluid Mechanics 645 (February 22, 2010): 529–39. http://dx.doi.org/10.1017/s0022112009993065.

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Transition to turbulence in a pipe is characterized by the increase of the characteristic lifetimes of localized turbulent spots (‘puffs’) with increasing Reynolds number (Re). Previous experiments are based on visualization or indirect measurements of the lifetime probability. Here we report quantitative direct measurements of the lifetimes based on accurate pressure measurements combined with laser Doppler anemometry (LDA). The characteristic lifetime is determined directly from the lifetime probability. It is shown that the characteristic lifetime does not diverge at finite Re, and follows an exponential scaling for the observed range 1725 ≤ Re ≤ 1955. Over this small Re range the lifetime increases over four orders of magnitude. The results show that the puff velocity is not constant, and the rapid disintegration of puffs occurs within 20–70 pipe diameters.

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Pfalzner, Susanne. "Deriving Median Disk Lifetimes from Disk Lifetime Distributions." Research Notes of the AAS 6, no. 10 (October 21, 2022): 219. http://dx.doi.org/10.3847/2515-5172/ac9b53.

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Abstract Observations show that individual protoplanetary disk lifetimes vary from <1 Myr to ≫20 Myr. The disk lifetime distribution is currently unknown. For the example of a Gaussian distribution of the disk lifetime, I suggest a simple method for deducing such a disk lifetimes distribution. The median disk lifetimes inferred with this method is also shown.

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Di Crescenzo, Antonio, Patrizia Di Gironimo, and Suchandan Kayal. "Analysis of the Past Lifetime in a Replacement Model through Stochastic Comparisons and Differential Entropy." Mathematics 8, no. 8 (July 22, 2020): 1203. http://dx.doi.org/10.3390/math8081203.

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A suitable replacement model for random lifetimes is extended to the context of past lifetimes. At a fixed time u an item is planned to be replaced by another one having the same age but a different lifetime distribution. We investigate the past lifetime of this system, given that at a larger time t the system is found to be failed. Subsequently, we perform some stochastic comparisons between the random lifetimes of the single items and the doubly truncated random variable that describes the system lifetime. Moreover, we consider the relative ratio of improvement evaluated at x ∈ ( u , t ) , which is finalized to measure the goodness of the replacement procedure. The characterization and the properties of the differential entropy of the system lifetime are also discussed. Finally, an example of application to the firing activity of a stochastic neuronal model is provided.

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Hooper, I. R., E. Khorani, X. Romain, L. E. Barr, T. Niewelt, S. Saxena, A. Wratten, N. E. Grant, J. D. Murphy, and E. Hendry. "Engineering the carrier lifetime and switching speed in Si-based mm-wave photomodulators." Journal of Applied Physics 132, no. 23 (December 21, 2022): 233102. http://dx.doi.org/10.1063/5.0128234.

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For a diverse range of semiconductor devices, the charge carrier lifetime is an essential characteristic. However, the carrier lifetime is difficult to control, as it is usually determined by a variety of recombination processes. For indirect bandgap materials, it is well known that effective carrier lifetimes can be improved by passivating the surface, effectively extinguishing surface-related recombination processes. However, for some applications, such as photomodulators for sub-infrared radiation, it is beneficial to tailor lifetimes to specific values, in this particular case trading off between photo-efficiency and switching speed. In this paper, we design a new type of silicon-based metamaterial with a tunable electron–hole lifetime. By periodically patterning a dielectric surface passivation layer, we create a metamaterial whereby the filling fraction of passivated relative to unpassivated areas dictates the effective charge carrier lifetime. We demonstrate tunable lifetimes between 200 μs and 8 ms in a 670 μm thick Si wafer, though in principle our approach allows one to generate any lifetime between the fully passivated and unpassivated limits of a bulk semiconductor. Finally, we investigate the application of these metamaterials as photomodulators, finding switching times that depend upon both the photoexcitation intensity, wafer thickness, and the carrier lifetime.

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Murphy, J. D., N. E. Grant, S. L. Pain, T. Niewelt, A. Wratten, E. Khorani, V. P. Markevich, et al. "Carrier lifetimes in high-lifetime silicon wafers and solar cells measured by photoexcited muon spin spectroscopy." Journal of Applied Physics 132, no. 6 (August 14, 2022): 065704. http://dx.doi.org/10.1063/5.0099492.

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Photoexcited muon spin spectroscopy (photo- μSR) is used to study excess charge carrier lifetimes in silicon. Experiments are performed on silicon wafers with very high bulk lifetimes with the surface passivation conditions intentionally modified to control the effective lifetime. When the effective lifetime is low (<500 μs), implanting the muons to different depths enables the reliable measurement of carrier lifetime as a function of distance from a surface. It is also demonstrated that the photo- μSR technique can measure effective carrier lifetimes in completed commercial gallium doped silicon passivated emitter and rear cell devices, with results validated with harmonically modulated photoluminescence imaging. It is discovered, however, that prolonged muon irradiation of samples with very long effective lifetimes (>10 ms) results in detectable degradation of the measured lifetime. Re-passivation of degraded samples with a temporary room temperature superacid-based passivation scheme demonstrates that degradation occurs in the silicon bulk. Deep-level transient spectroscopy measurements reveal the existence of several defect-related traps near the muon-exposed surface in concentrations of order 1010 cm−3 that are not present near the surface not exposed to muons. In contrast to the common perception of the μSR technique, our results demonstrate that muons are not inert probes and that beam-induced recombination activity modifies the bulk lifetime significantly in samples with high effective carrier lifetimes.

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Walczysko, Petr, Ute Kuhlicke, Sabine Knappe, Christiana Cordes, and Thomas R. Neu. "In Situ Activity of Suspended and Immobilized Microbial Communities as Measured by Fluorescence Lifetime Imaging." Applied and Environmental Microbiology 74, no. 1 (November 2, 2007): 294–99. http://dx.doi.org/10.1128/aem.01806-07.

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ABSTRACT In this study, the feasibility of fluorescence lifetime imaging (FLIM) for measurement of RNA:DNA ratios in microorganisms was assessed. The fluorescence lifetime of a nucleic acid-specific probe (SYTO 13) was used to directly measure the RNA:DNA ratio inside living bacterial cells. In vitro, SYTO 13 showed shorter fluorescence lifetimes in DNA solutions than in RNA solutions. Growth experiments with bacterial monocultures were performed in liquid media. The results demonstrated the suitability of SYTO 13 for measuring the growth-phase-dependent RNA:DNA ratio in Escherichia coli cells. The fluorescence lifetime of SYTO 13 reflected the known changes of the RNA:DNA ratio in microbial cells during different growth phases. As a result, the growth rate of E. coli cells strongly correlated with the fluorescence lifetime. Finally, the fluorescence lifetimes of SYTO 13 in slow- and fast-growing biofilms were compared. For this purpose, biofilms developed from activated sludge were grown as autotrophic and heterotrophic communities. The FLIM data clearly showed a longer fluorescence lifetime for the fast-growing heterotrophic biofilms and a shorter fluorescence lifetime for the slow-growing autotrophic biofilms. Furthermore, starved biofilms showed shorter lifetimes than biofilms supplied with glucose, indicating a lower RNA:DNA ratio in starved biofilms. It is suggested that FLIM in combination with SYTO 13 represents a useful tool for the in situ differentiation of active and inactive bacteria. The technique does not require radioactive chemicals and may be applied to a broad range of sample types, including suspended and immobilized microorganisms.

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Bae, Hong-Kyun, Jeewon Ahn, Dongwon Lee, and Sang-Wook Kim. "LANCER: A Lifetime-Aware News Recommender System." Proceedings of the AAAI Conference on Artificial Intelligence 37, no. 4 (June 26, 2023): 4141–48. http://dx.doi.org/10.1609/aaai.v37i4.25530.

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From the observation that users reading news tend to not click outdated news, we propose the notion of 'lifetime' of news, with two hypotheses: (i) news has a shorter lifetime, compared to other types of items such as movies or e-commerce products; (ii) news only competes with other news whose lifetimes have not ended, and which has an overlapping lifetime (i.e., limited competitions). By further developing the characteristics of the lifetime of news, then we present a novel approach for news recommendation, namely, Lifetime-Aware News reCommEndeR System (LANCER) that carefully exploits the lifetime of news during training and recommendation. Using real-world news datasets (e.g., Adressa and MIND), we successfully demonstrate that state-of-the-art news recommendation models can get significantly benefited by integrating the notion of lifetime and LANCER, by up to about 40% increases in recommendation accuracy.

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Triantou, K., K. Mergia, and I. E. Stamatelatos. "Positron Annihilation Lifetime Spectroscopy in the study of defects in materials." HNPS Proceedings 24 (April 1, 2019): 235. http://dx.doi.org/10.12681/hnps.1872.

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The Positron Annihilation Lifetime Spectroscopy (PALS) is a valuable method for the study of the open volume defects in materials. The reduced electron density at the vacant/defect site increases the positron lifetime, and positron lifetime increases as the size of defect increases. In the current paper the experimental apparatus for the measurement of the positron lifetime in materials is described and the spectra from W and Cd specimens are analyzed. The presence of dislocations and vacancy defects is found, since the positron lifetimes of specimens are higher than the defect-free (bulk) values.

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Udal, Andres, and Enn Velmre. "Investigation of Charge Carrier Lifetime Temperature-Dependence in 4H-SiC Diodes." Materials Science Forum 556-557 (September 2007): 375–78. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.375.

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Recently published experimental results for 4H–SiC diodes up to 700 °C are used to deduce the hole lifetime temperature-dependence in n-base for high temperature range. The reverse recovery measurements are interpreted by the nonisothermal drift-diffusion simulator DYNAMIT. The uncertainties from lifetimes unknown behavior in emitter layers and consequences from possible nonuniform lifetime distribution in n-base are analyzed. Results show that up to temperature 400 °C nearly quadratic dependence of lifetime versus temperature τ ~ T 2 holds. At higher temperatures lifetime growth is accelerated approximately to quartic dependence τ ~ T 4.

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Iranian, Pooria, Thomas Lapauw, Thomas Van den Dries, Sevada Sahakian, Joris Wuts, Valéry Ann Jacobs, Jef Vandemeulebroucke, Maarten Kuijk, and Hans Ingelberts. "Fluorescence Lifetime Endoscopy with a Nanosecond Time-Gated CAPS Camera with IRF-Free Deep Learning Method." Sensors 25, no. 2 (January 14, 2025): 450. https://doi.org/10.3390/s25020450.

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Fluorescence imaging has been widely used in fields like (pre)clinical imaging and other domains. With advancements in imaging technology and new fluorescent labels, fluorescence lifetime imaging is gradually gaining recognition. Our research department is developing the tauCAMTM, based on the Current-Assisted Photonic Sampler, to achieve real-time fluorescence lifetime imaging in the NIR (700–900 nm) region. Incorporating fluorescence lifetime into endoscopy could further improve the differentiation of malignant and benign cells based on their distinct lifetimes. In this work, the capabilities of an endoscopic lifetime imaging system are demonstrated using a rigid endoscope involving various phantoms and an IRF-free deep learning-based method with only 6-time points. The results show that this application’s fluorescence lifetime image has better lifetime uniformity and precision with 6-time points than the conventional methods.

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Reshanov, Sergey A., Wolfgang Bartsch, Bernd Zippelius, and Gerhard Pensl. "Lifetime Investigations of 4H-SiC PiN Power Diodes." Materials Science Forum 615-617 (March 2009): 699–702. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.699.

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Lifetime measurements are performed on 4H-SiC pin power diodes (6.5 kV). The lifetime values in the base range from 1.1 s to 2.1 s; these values demonstrate the high quality of the 4H-SiC epilayer and the optimized device processing. The observed lifetimes are correlated with deep defect centers detected by deep level transient spectroscopy. The role of the Z1/2-center as a lifetime killer is discussed.

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Abu-Baker, Amjad, Hong Huang, and Satyajayant Misra. "Maximizing lifetime sequences of wireless sensor networks powered by renewable energy." Sensor Review 34, no. 4 (August 26, 2014): 374–81. http://dx.doi.org/10.1108/sr-09-2012-704.

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Purpose – The purpose of this paper is to investigate conditional and unconditional lifetime sequence of wireless sensor networks (WSN) that have many important practical applications. A significant limitation for WSN is its short lifetime due to the limited capacity of the battery. Renewable energy can significantly extend the lifetime of WSN. In this paper, we investigate the whole sequence of lifetimes of every sensor in WSN, as different application scenarios have different requirement on how many sensors can die until the WSN is no longer functional. Design/methodology/approach – Linear programming formulation was used to investigate both the conditional and unconditional lifetime sequence of WSN. The lifetime sequences of WSN without and with differ levels of solar power were studied. Findings – This investigation of lifetime sequences discovered three interesting phenomena: the sensors that die first are on the peripheral of the network, rather close to the base station; multiple sensors tend to die simultaneously; and the lifetimes of sensors that die later can be extended by renewable energy much more significantly than those that die early, which is very good news to applications that can tolerate the death of a fraction of sensors. Originality/value – In this paper, the first optimization formulation for maximizing both unconditional and conditional lifetime sequences of WSNs with renewable energy sources was provided. Only the conditional lifetime sequence has been investigated in a previous work, but this method runs n-times faster than the previous work, with n being the number of nodes in the WSN.

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Yeh, Chun-Lang. "Effect of Burner Operation on the Catalyst Tube Lifetime of a Steam Methane Reformer: A Numerical Study." Applied Sciences 11, no. 1 (December 29, 2020): 231. http://dx.doi.org/10.3390/app11010231.

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In this paper, the catalyst tube lifetime of a practical steam methane reformer is analyzed numerically. The effect of burner operating mode on the flow development, hydrogen yield, and catalyst tube lifetime is discussed, with the aim of improving the reformer performance. The results of this study reveal that using the periodic boundary conditions, the temperatures and hydrogen yields obtained are much lower than the experimental values and the pressures are much lower than those using the real model. This results in overestimating the catalyst tube lifetime and underestimating the reformer operation risk. The catalyst tubes in the downstream area have longer lifetimes, while those in the upstream area have shorter lifetimes. Turning the upstream burners off is more efficient to the catalyst tube lifetime, while turning off the central groups of burners is less efficient. The main drawback of turning off burners is the decrease of hydrogen yield.

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VĂDUVA, Ion. "A PARTICULAR LIFETIME DISTRIBUTION." Review of the Air Force Academy 15, no. 2 (October 20, 2017): 5–14. http://dx.doi.org/10.19062/1842-9238.2017.15.2.1.

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Chung, Gil Yong, Mark J. Loboda, M. J. Marinella, D. K. Schroder, Paul B. Klein, Tamara Isaacs-Smith, and J. W. Williams. "Generation and Recombination Carrier Lifetimes in 4H SiC Epitaxial Wafers." Materials Science Forum 600-603 (September 2008): 485–88. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.485.

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Compared to silicon, there have been relatively few comparative studies of recombination and carrier lifetimes in SiC. For the first time, both generation and recombination carrier lifetimes are reported from the same areas in 20 m thick 4H SiC n-/n+ epi-wafer structures. The ratio of the generation to recombination lifetime is much different in SiC compared to Si. Activation energy calculated from SiC generation lifetimes shows that traps with energy levels near mid-gap dominate the generation lifetime. Comparison of both generation and recombination lifetimes and dislocation counts measured in the device area show no correlation in either case.

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Yu, Chun-Min, Kuen-Suan Chen, and Ting-Hsin Hsu. "Confidence-Interval-Based Fuzzy Testing for the Lifetime Performance Index of Electronic Product." Mathematics 10, no. 9 (April 22, 2022): 1405. http://dx.doi.org/10.3390/math10091405.

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When the lifetime of an electronic component does not reach the required level, it can be enhanced by means of the paralleling current sharing backup system or the redundant backup system. The lifetime of the redundant backup system is the sum of lifetimes of all electronic components, which is the maximum of all the electronic components’ lifetimes, compared with the lifetime of the parallel current sharing backup system. For the purpose of enhancing products’ reliability, electronic goods are usually designed with spare electronic components. If it is assumed that there are m−1 redundant backup components for each electronic product, then the lifetime of the electronic product will be distributed as a Gamma distribution with two parameters—m and λ, where λ is the mean for each lifetime of each electronic component. According to numerous studies, the sample size is not large, as it takes a long time to test the lifetime of an electronic product, and enterprises consider cost and timeliness. This paper concerns the performance index of the lifetime of the electronic product. Therefore, based on the confidence interval, this paper aims to develop a fuzzy testing model. As this model can integrate past data and expert experience, the testing accuracy can be retained despite small-sized samples. In fact, through adopting the testing model proposed by this paper, companies can make precise and intelligent decisions instantly with the use of small-sized samples to grasp the opportunities for improvement.

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Hewitt, Joseph D., and Linda B. McGown. "On-the-Fly Fluorescence Lifetime Detection of Humic Substances in Capillary Electrophoresis." Applied Spectroscopy 57, no. 3 (March 2003): 256–65. http://dx.doi.org/10.1366/000370203321558155.

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On-the-fly fluorescence lifetime detection was investigated as a tool for studying humic substances in capillary zone electrophoresis (CZE). Humic substances are complex, heterogeneous mixtures of natural products that tend to migrate in a single, broad CZE peak. The intrinsic fluorescence lifetime of five humic substances from the International Humic Substances Society (IHSS) was monitored using excitation at 488 or 364 nm to produce intensity-lifetime electropherograms for each of the substances. Each frequency-domain lifetime measurement, collected at sub-second intervals during the CZE run, contains the equivalent of a complete decay profile. Lifetime analysis of each decay profile was used to construct a lifetime-resolved electropherogram for each lifetime component, from which the variation in relative intensity contributions of each lifetime across the broad CZE peak could be determined. Absorption spectra, fluorescence excitation–emission spectra, and lifetime profiles of batch solutions of the samples were determined as well. It was found that, whereas absorption and fluorescence spectral characteristics tended to discriminate between humic acids and fulvic acids, the batch solution lifetime profiles discriminated instead between samples from different sources, regardless of fraction. On-the-fly lifetime detection provided a more detailed view of the fluorescence decay of the samples, including greater resolution of lifetimes for two of the fulvic acids and greater discrimination among samples based on lifetime profiles across the CZE peaks.

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Hemmingsen, Sherry L., and Linda B. McGown. "Phase-Resolved Fluorescence Spectral and Lifetime Characterization of Commercial Humic Substances." Applied Spectroscopy 51, no. 7 (July 1997): 921–29. http://dx.doi.org/10.1366/0003702971941458.

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Phase-resolved excitation-emission matrices (PREEMs) are shown to provide a unique visual representation of the intrinsic fluorescence properties of humic acids under a variety of solution conditions. The calculation of spectral peak ratios in PREEMs as well as steady-state excitation-emission matrices provides a convenient means for quantitating differences between the spectra with good precision. Absorbance correction is shown to be essential for accurate comparison among spectral features. Increased detail is available from PREEMs at various modulation frequencies that reveal the distribution of fluorescence lifetime contributions across the spectral surface. Direct measurement of fluorescence lifetime recovered three ranges of lifetime components in the humic substances, <1 ns, 2–5 ns, and 8–14 ns, that are consistent with previously reported lifetimes. PREEMs, which provide a concise “survey” of how the lifetimes change across the spectrum, may aid in pinpointing spectral regions that provide the best lifetime discrimination among samples.

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Wu, Shu-Fei, and Kuan-Yi Chiang. "Assessment of the Overall Lifetime Performance Index of Weibull Products in Multiple Production Lines." Mathematics 12, no. 4 (February 7, 2024): 514. http://dx.doi.org/10.3390/math12040514.

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Process capability indices have been extensively employed to assess process performance in order to drive ongoing enhancements in quality and productivity, where the larger, the better for these lifetime performance indices. For multiple production lines, an overall lifetime performance index is proposed and the relationship between the overall lifetime performance index and the individual lifetime performance index is displayed. For products with lifetimes following the Weibull distribution for the ith production line, the maximum likelihood estimator and asymptotic distribution for the individual lifetime performance index were investigated so that the maximum likelihood estimator and asymptotic distribution for the overall lifetime performance index were also derived. Based on the pre-assigned target value of the overall lifetime performance index, the target value of an individual lifetime performance index could be determined. To test whether the overall lifetime performance index reached the target value was equivalent to testing whether the individual lifetime performance index reached the corresponding target value. The testing procedure based on the maximum likelihood estimator is given in this paper and the analysis of test power is displayed by figures. Finally, one practical example is given to illustrate the use of this testing algorithmic procedure to determine whether the overall production process was capable.

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RAMIREZ, JUAN EDUARDO. "A HIGH STATISTICS MEASUREMENT OF Ξc LIFETIMES." International Journal of Modern Physics A 16, supp01b (September 2001): 508–10. http://dx.doi.org/10.1142/s0217751x01007340.

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Preliminary results of the charm-strange baryon lifetimes from the FOCUS experiment at Fermilab are presented. The [Formula: see text] lifetime is determined to be 0.440±0.031 ps and the [Formula: see text] lifetime to be 0.124±0.013 ps. The systematic errors are still under review.

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Wu, Shu-Fei, and Wei-Tsung Chang. "The Evaluation on the Process Capability Index CL for Exponentiated Frech’et Lifetime Product under Progressive Type I Interval Censoring." Symmetry 13, no. 6 (June 8, 2021): 1032. http://dx.doi.org/10.3390/sym13061032.

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We present the likelihood inferences on the lifetime performance index CL to evaluate the performance of lifetimes of products following the skewed Exponentiated Frech’et distribution in many manufacturing industries. This research is related to the topic of skewed Probability Distributions and Applications across Disciplines. Exponentiated Frech’et distribution is a generalization of some lifetime distributions. The maximum likelihood estimator for CL for lifetimes with exponentiated Frech’et distribution is derived to develop a computational testing procedure so that experimenters can implement it to test whether the lifetime performance reached the pre-assigned level of significance with a given lower specification limit under progressive type I interval censoring. At the end, two examples are provided to demonstrate the implementation on the algorithm for our proposed computational testing procedure.

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Ishibashi, Shoji, Madoka Tokumoto, Nobumori Kinoshita, Norio Terada, Hideo Ihara, Ryoichi Suzuki, Toshiyuki Ohdaira, Tomohisa Mikado, and Hiroyuki Anzai. "Positron lifetimes in molecular crystals." Canadian Journal of Physics 74, no. 7-8 (July 1, 1996): 534–39. http://dx.doi.org/10.1139/p96-077.

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Positron lifetime measurements were carried out on molecular crystals of C60, TTF-TCNQ, and (BEDT-TTF)2Cu(NCS)2 utilizing a pulsed variable-energy positron beam. Each lifetime spectrum is well described by a single component. Their values are 390, 338, and 357 ps, respectively. In addition, positron lifetimes were calculated theoretically. The electronic density was obtained by the superposed-neutral-atom model or quantum-chemical molecular-orbital calculations with various basis sets. The lifetime enhancement due to the positron–electron correlation was taken into account through an enhancement factor as a function of the high-frequency dielectric constant in the local density approximation or a gradient correction in the generalized gradient approximation. The results are compared with the measured lifetimes.

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Alshehri, Mashael A., and Mohamed Kayid. "Mean Residual Lifetime Frailty Models: A Weighted Perspective." Mathematical Problems in Engineering 2021 (December 13, 2021): 1–21. http://dx.doi.org/10.1155/2021/3974858.

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The mean residual life frailty model and a subsequent weighted multiplicative mean residual life model that requires weighted multiplicative mean residual lives are considered. The expression and the shape of a mean residual life for some semiparametric models and also for a multiplicative degradation model are given in separate examples. The frailty model represents the lifetime of the population in which the random parameter combines the effects of the subpopulations. We show that for some regular dependencies of the population lifetime on the random parameter, some aging properties of the subpopulations’ lifetimes are preserved for the population lifetime. We indicate that the weighted multiplicative mean residual life model generates positive dependencies of this type. The copula function associated with the model is also derived. Necessary and sufficient conditions for certain aging properties of population lifetimes in the model are determined. Preservation of stochastic orders of two random parameters for the resulting population lifetimes in the model is acquired.

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Bowman, Adam J., Cheng Huang, Mark J. Schnitzer, and Mark A. Kasevich. "Wide-field fluorescence lifetime imaging of neuron spiking and subthreshold activity in vivo." Science 380, no. 6651 (June 23, 2023): 1270–75. http://dx.doi.org/10.1126/science.adf9725.

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The development of voltage-sensitive fluorescent probes suggests fluorescence lifetime as a promising readout for electrical activity in biological systems. Existing approaches fail to achieve the speed and sensitivity required for voltage imaging in neuroscience applications. We demonstrated that wide-field electro-optic fluorescence lifetime imaging microscopy (EO-FLIM) allows lifetime imaging at kilohertz frame-acquisition rates, spatially resolving action potential propagation and subthreshold neural activity in live adult Drosophila . Lifetime resolutions of <5 picoseconds at 1 kilohertz were achieved for single-cell voltage recordings. Lifetime readout is limited by photon shot noise, and the method provides strong rejection of motion artifacts and technical noise sources. Recordings revealed local transmembrane depolarizations, two types of spikes with distinct fluorescence lifetimes, and phase locking of spikes to an external mechanical stimulus.

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Booker, I. D., Jawad ul Hassan, Anders Hallén, Einar Ö. Sveinbjörnsson, Olof Kordina, and Peder Bergman. "Comparison of Post-Growth Carrier Lifetime Improvement Methods for 4H-SiC Epilayers." Materials Science Forum 717-720 (May 2012): 285–88. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.285.

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We compare two methods for post-growth improvement of bulk carrier lifetime in 4H-SiC: dry oxidations and implantations with either 12C or 14N, followed by high temperature anneals in Ar atmosphere. Application of these techniques to samples cut from the same wafer/epilayer yields 2- to 11-fold lifetime increases, with the implantation/annealing technique shown to give greater maximum lifetimes. The maximum lifetimes reached are ~5μs after 12C implantation at 600°C and annealing in Ar for 180 minutes at 1500°C. Higher temperatures give decreased lifetimes, a result which differs from reports in literature.

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Batthula, Venkata Jaipal Reddy, Richard S. Segall, Daniel Berleant, Hyacinthe Aboudja, and Peng-Hung Tsai. "Future Satellite Lifetime Prediction From the Historical Trend in Satellite Half-Lives." Journal of Systemics, Cybernetics and Informatics 20, no. 3 (June 2022): 40–45. http://dx.doi.org/10.54808/jsci.20.03.40.

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Satellite lifetime is one of the important characteristics of satellite design and construction. It’s also of practical importance to know when a satellite is about to fail, as reentry and disposal can become operational matters. Satellite lifetime estimation is not necessarily a one-time action, but can be repeated, and it depends on many factors such as orbital parameters, operational requirements, and various others. Many products today are designed with safety, quality, and service life in mind. Based on the historical trend in satellite lifetimes, the approach used here is to predict the lifetimes of satellites using half-life values of their launch year cohorts. Half-life calculations can be made using either launch year or failure year cohorts, making a comparison of these of interest in forecasting the future lifetimes of satellites. This study focuses on analyzing satellite half-lives and using that information to project lifetimes of satellites that are still operational from the satellite launch year. We examine conformance of satellite lifetime data to fitted curves that remove noise from the data and thereby predict lifetimes of satellites from their launch year cohorts.

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Koh, Dongjoo, Song Won Ko, Jung In Yang, Betul Akkopru-Akgun, and Susan Trolier-McKinstry. "Effect of Mg-doping and Fe-doping in lead zirconate titanate (PZT) thin films on electrical reliability." Journal of Applied Physics 132, no. 17 (November 7, 2022): 174101. http://dx.doi.org/10.1063/5.0101308.

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Uniformly acceptor doped Pb(Zr0.48Ti0.52)O3 (PZT) films with 2 mol. % Mg or Fe prepared by chemical solution deposition exhibited decreased dielectric constants and remanent polarizations relative to undoped PZT. For highly accelerated lifetime testing (HALT) at 200 °C and an electric field of 300 kV/cm in the field up direction, the HALT lifetimes (t50) for undoped, Mg-doped, and Fe-doped PZT films were shortened from 2.81 ± 0.1 to 0.21 ± 0.1 and 0.54 ± 0.04 h, respectively. Through thermally stimulated depolarization current measurement, significant [Formula: see text] electromigration was found in homogeneously Mg-doped PZT thin films, a major factor in their short HALT lifetime. Because the concentration of oxygen vacancies increases with uniform acceptor doping, the lifetime decreases. In contrast, when a thin layer of Mg-doped or Fe-doped PZT was deposited on undoped PZT or Nb-doped PZT (PNZT), the HALT lifetimes were longer than those of pure PZT or PNZT films. This confirms prior work on PNZT films with a Mn-doped top layer, demonstrating that the HALT lifetime increases for composite films when a layer with multivalent acceptors is present near the negative electrode during HALT. In that case, the compensating electrons are trapped, presumably on the multivalent acceptors, thus increasing the lifetime.

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Roelofs, G. J. "A steady-state analysis of the temperature responses of water vapor and aerosol lifetimes." Atmospheric Chemistry and Physics 13, no. 16 (August 21, 2013): 8245–54. http://dx.doi.org/10.5194/acp-13-8245-2013.

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Abstract. The dominant removal mechanism of soluble aerosol is wet deposition. The atmospheric lifetime of aerosol, relevant for aerosol radiative forcing, is therefore coupled to the atmospheric cycling time of water vapor. This study investigates the coupling between water vapor and aerosol lifetimes in a well-mixed atmosphere. Based on a steady-state study by Pruppacher and Jaenicke (1995) we describe the coupling in terms of the processing efficiency of air by clouds and the efficiencies of water vapor condensation, of aerosol activation, and of the transfer from cloud water to precipitation. We extend this to expressions for the temperature responses of the water vapor and aerosol lifetimes. Previous climate model results (Held and Soden, 2006) suggest a water vapor lifetime temperature response of +5.3 ± 2.0% K−1. This can be used as a first guess for the aerosol lifetime temperature response, but temperature sensitivities of the aerosol lifetime simulated in recent aerosol–climate model studies extend beyond this range and include negative values. This indicates that other influences probably have a larger impact on the computed aerosol lifetime than its temperature response, more specifically changes in the spatial distributions of aerosol (precursor) emissions and precipitation patterns, and changes in the activation efficiency of aerosol. These are not quantitatively evaluated in this study but we present suggestions for model experiments that may help to understand and quantify the different factors that determine the aerosol atmospheric lifetime.

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Xu, Jing, Gang Yan, and Ming Lu. "Evaluation of the Minority-Carrier Lifetime of IMM3J Solar Cells under Proton Irradiation Based on Electroluminescence." Crystals 13, no. 2 (February 10, 2023): 297. http://dx.doi.org/10.3390/cryst13020297.

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The shortening of the minority carrier lifetime is the main reason for the degradation of the electrical performance of solar cells; therefore, it is particularly important to evaluate the minority carrier lifetime of inverted metamorphic triple junction (IMM3J) GaInP/GaAs/InGaAs solar cells. We evaluate the minority carrier lifetime of each subcell of IMM3J solar cells before and after 2 MeV proton irradiation by the electroluminescence (EL) method. Before proton irradiation, the minority carrier lifetimes of the GaInP, GaAs, and InGaAs subcells were 6.99 × 10−9 s, 3.09 × 10−8 s, and 2.31 × 10−8 s, respectively. After proton irradiation, the minority carrier lifetime of GaInP, GaAs, and InGaAs subcells degraded significantly. When the proton fluence was 2 × 1012 cm−2, the minority carrier lifetimes of the GaInP, GaAs, and InGaAs subcells degraded to 1.63 × 10−10 s, 1.56 × 10−11 s, and 1.65 × 10−10 s, respectively. These results provide a reference for predicting the degradation of the short-circuit current and open-circuit voltage of each subcell.

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Geng, Hongwei, Shanlin Pan, and Dehong Hu. "Electrogenerated Chemiluminescence and Fluorescence Lifetime Spatial Heterogeneity of Poly (2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) in Presence of [6,6]-phenyl-C61-butyric Acid Methyl Ester." MRS Proceedings 1493 (2013): 263–68. http://dx.doi.org/10.1557/opl.2013.19.

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ABSTRACTWe present electrogenerated chemiluminescence (ECL) and fluorescence lifetime mapping of MEH-PPV/PCBM thin films. The ECL results show that the oxidation peak of MEH-PPV near 0.7 V (vs. SCE) and ECL response of films shifted positively towards 1.2 V in the presence of PCBM. At the same time, the oxidation current density of MEH-PPV increases along with the decrease of ECL intensity in the presence of PCBM. The fluorescence lifetime images clearly show that the lifetime spatial heterogeneities are affected by different substrates and MEH-PPV/PCBM ratios. Meanwhile, the lifetime of MEH-PPV decreases with the increasing of film thickness. The lifetimes of MEH-PPV films on TiO2 substrate are lower than films on glass.

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Zhou, Meng, Tatsuya Higaki, Guoxiang Hu, Matthew Y. Sfeir, Yuxiang Chen, De-en Jiang, and Rongchao Jin. "Three-orders-of-magnitude variation of carrier lifetimes with crystal phase of gold nanoclusters." Science 364, no. 6437 (April 19, 2019): 279–82. http://dx.doi.org/10.1126/science.aaw8007.

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Atomic packing controls exciton lifetime Like semiconductors, small metallic clusters can absorb light and create excitons (electron-hole pairs). In ligand-capped gold clusters of 30 to 40 atoms (Au 30 to Au 40 ) that adopt the usual face-centered cubic packing, the lifetime of these excitons is ∼100 nanoseconds. Zhou et al. found that atomic packing and molecular orbital overlap can greatly affect carrier lifetimes. Despite having similar bandgaps to those of face-centered cubic clusters, a hexagonal close-packed Au 30 cluster had a much shorter lifetime (∼1 nanosecond), and a body-centered cubic Au 38 cluster had a lifetime of ∼5 microseconds, which is comparable to bulk silicon. Science , this issue p. 279

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Pisarska, Joanna, Wojciech A. Pisarski, Radosław Lisiecki, and Witold Ryba-Romanowski. "Phonon Sideband Analysis and Near-Infrared Emission in Heavy Metal Oxide Glasses." Materials 14, no. 1 (December 30, 2020): 121. http://dx.doi.org/10.3390/ma14010121.

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In this work, spectroscopic properties of europium and erbium ions in heavy metal oxide glasses have been studied. The phonon energy of the glass host was determined based on Eu3+ excitation spectra measurements. Near-IR emission spectra at 1550 nm related to 4I13/2 → 4I15/2 transition of erbium in heavy metal glasses were examined with special regards to luminescence bandwidth and measured lifetime. In particular, correlation between phonon energy and the measured lifetime 4I13/2 (Er3+) was proposed. The luminescence lifetime for the 4I13/2 upper laser state of erbium decreases with increasing phonon energy in glass matrices. Completely different results were obtained glass samples with europium ions, where the 5D0 lifetime increases with increasing phonon energy. Our investigations suggest that the values of measured 5D0 lifetime equal to radiative lifetimes for all heavy metal oxide glasses.

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Clayton, Andrew H. A. "Phase-Sensitive Fluorescence Image Correlation Spectroscopy." International Journal of Molecular Sciences 25, no. 20 (October 17, 2024): 11165. http://dx.doi.org/10.3390/ijms252011165.

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Fluorescence lifetime imaging microscopy is sensitive to molecular interactions and environments. In homo-dyne frequency-domain fluorescence lifetime imaging microscopy, images of fluorescence objects are acquired at different phase settings of the detector. The detected intensity as a function of detector phase is a sinusoidal function that is sensitive to the lifetime of the fluorescent species. In this paper, the theory of phase-sensitive fluorescence image correlation spectroscopy is described. In this version of lifetime imaging, image correlation spectroscopy analysis (i.e., spatial autocorrelation) is applied to successive fluorescence images acquired at different phase settings of the detector. Simulations of different types of lifetime distributions reveal that the phase-dependent density of fluorescent objects is dependent on the heterogeneity of lifetimes present in the objects. We provide an example of this analysis workflow to a cervical cancer cell stained with a fluorescent membrane probe.

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PAULINI, MANFRED. "PROPERTIES OF HEAVY B HADRONS." International Journal of Modern Physics A 24, no. 24 (September 30, 2009): 4413–35. http://dx.doi.org/10.1142/s0217751x09046114.

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We review recent measurements of heavy B hadron states including masses and lifetimes of the [Formula: see text] meson as well as excited B states [Formula: see text]. We discuss properties of the [Formula: see text] meson such as lifetime, lifetime difference ΔΓs/Γs and CP violation in [Formula: see text] decays. We also summarize new measurements of the masses and lifetimes of bottom baryons including the [Formula: see text] baryon, the Σb baryon states as well as the [Formula: see text] and [Formula: see text] baryons.

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Bieniek, M., and M. Burkschat. "On unimodality of the lifetime distribution of coherent systems with failure-dependent component lifetimes." Journal of Applied Probability 55, no. 2 (June 2018): 473–87. http://dx.doi.org/10.1017/jpr.2018.31.

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Abstract We study the conditions for unimodality of the lifetime distribution of a coherent system when the ordered component lifetimes in the system are described by generalized order statistics. Results for systems with independent and identically distributed lifetimes of components are included in this setting. The findings are illustrated with some examples for different types of systems. In particular, coherent systems with strictly bimodal density functions are presented in the case of independent standard uniform distributed lifetimes of components. Furthermore, we use the results to derive a sharp upper bound on the expected system lifetime in terms of the mean and the standard deviation of the underlying distribution.

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Chung, Gil Yong, Mark J. Loboda, Siddarth G. Sundaresan, and Ranbir Singh. "Correlation between Carrier Recombination Lifetime and Forward Voltage Drop in 4H-SiC PiN Diodes." Materials Science Forum 645-648 (April 2010): 905–8. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.905.

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Correlation between carrier lifetime and forward voltage drop in 4H-SiC PiN diodes has been investigated. PiN diodes from the drift layer of 20 m shows breakdown voltage of 3.3 kV and forward voltage drop as low as 3.13 V at 100A/cm2. Variation of calculated forward voltage drop ( ) from measured carrier lifetimes is very comparable to measured of fully processed PiN diodes. Measured carrier lifetime and of PiN diodes also show good spatial correlation. Wafer level lifetime mapping can be employed to assess and predict of PiN diodes.

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Journal articles on the topic 'Lifetime'

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