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The Study of Electroluminescence and Reliability of Polyimide Films in High DC Fields
摘要： Electroluminescence (EL) intensity of the polyimide (PI) films was tested under dc high electric field by home-made experimental device. The results showed that the EL intensity of PI films increased along with the electric field. EL intensity is approximately to background intensity when the electric-field intensity was less than 2.00 MV/cm. EL intensity increases along with increasing the electric field when electric-field intensity greater than 2.00 MV/cm. When electric-field at 2.80 MV/cm, EL intensity increasing strongly suggests that the excitation process related to hot electrons accelerated by the field approaching a critical threshold. Meanwhile, this work elaborates a method to deal with identical samples get different experimental data by using Weibull distribution method, and the concept of the reliability was presented. The nine groups of EL experimental data were analyzed, and the result showed that the lifetime of mid-value (t = 164.9 min). Mid-value of the breakdown field is E = 2.76 MV/cm.
关键词： reliability,breakdown,Weibull distribution,electroluminescence,PI films
更新于2025-09-23 15:23:52
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Preparation of ortho-symmetric double (OSD) Z-scheme SnO2\CdSe/Bi2O3 sonocatalyst by ultrasonic-assisted isoelectric point method for effective degradation of organic pollutants
摘要： In this paper, the maximum domain of attraction of the three-parameter conditional Exponential-Weibull distribution is studied. The conditional Exponential-Weibul distribution is confirmed and proven to belong to the maximum domain of attraction of the Gumbel distribution, and the expressions of the corresponding normalizing constants are derived. Numerical simulations are conducted to investigate the performance of the proposed normalizing constants.
关键词： Maximum domain of attraction,Exponential-Weibull distribution,Normalizing constants,Extreme value distribution
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - THz and IR detectors in applications : (Invited)
摘要： This paper investigates the efficiency of Gini’s mean difference (GMD) as a measure of variability in two commonly used process capability indices (PCIs), i.e., Cp and Cpk. A comparison has been carried out to evaluate the performance of GMD-based PCIs and Pearn and Chen quantile-based PCIs under low, moderate, and high asymmetry using Weibull distribution. The simulation results, under low and moderate asymmetric condition, indicate that GMD-based PCIs are more close to target values than quantile approach. Beside point estimation, nonparametric bootstrap confidence intervals, such as standard, percentile, and bias corrected percentile with their coverage probabilities also have been calculated. Using quantile approach, bias corrected percentile (BCPB) method is more effective for both Cp and Cpk, where as in case of GMD, both BCPB and percentile bootstrap method can be used to estimate the confidence interval of Cp and Cpk, respectively.
关键词： non-normal,Gini’s mean difference,process capability indices,Weibull distribution
更新于2025-09-23 15:19:57
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Probabilistic Generation Model of Solar Irradiance for Grid Connected Photovoltaic Systems Using Weibull Distribution
摘要： Around the world, countries are integrating photovoltaic generating systems to the grid to support climate change initiatives. However, solar power generation is highly uncertain due to variations in solar irradiance level during different hours of the day. Inaccurate modelling of this variability can lead to non-optimal dispatch of system resources. Therefore, accurate characterization of solar irradiance patterns is essential for effective management of renewable energy resources in an electrical power grid. In this paper, the Weibull distribution based probabilistic model is presented for characterization of solar irradiance patterns. Firstly, Weibull distribution is utilized to model inter-temporal variations associated with reference solar irradiance data through moving window averaging technique, and then the proposed model is used for irradiance pattern generation. To achieve continuity of discrete Weibull distribution parameters calculated at different steps of moving window, Generalized Regression Neural Network (GRNN) is employed. Goodness of Fit (GOF) techniques are used to calculate the error between mean and standard deviation of generated and reference patterns. The comparison of GOF results with the literature shows that the proposed model has improved performance. The presented model can be used for power system planning studies where the uncertainty of different resources such as generation, load, network, etc., needs to be considered for their better management.
关键词： solar power generation,irradiance patterns,Weibull distribution
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Study on Tarnishing Mechanism of Grid Lines on Crystalline Silicon Solar Cells
摘要： This paper investigates the efficiency of Gini’s mean difference (GMD) as a measure of variability in two commonly used process capability indices (PCIs), i.e., Cp and Cpk. A comparison has been carried out to evaluate the performance of GMD-based PCIs and Pearn and Chen quantile-based PCIs under low, moderate, and high asymmetry using Weibull distribution. The simulation results, under low and moderate asymmetric condition, indicate that GMD-based PCIs are more close to target values than quantile approach. Beside point estimation, nonparametric bootstrap confidence intervals, such as standard, percentile, and bias corrected percentile with their coverage probabilities also have been calculated. Using quantile approach, bias corrected percentile (BCPB) method is more effective for both Cp and Cpk, where as in case of GMD, both BCPB and percentile bootstrap method can be used to estimate the confidence interval of Cp and Cpk, respectively.
关键词： non-normal,Gini’s mean difference,process capability indices,Weibull distribution
更新于2025-09-23 15:19:57
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Performance evaluation for polarization shift keying modulation in atmospheric turbulence channel
摘要： The exponentiated Weibull (EW) distribution is adopted for all turbulence strengths when aperture averaging technology is applied. Firstly, the closed expression of the average bit error rate (BER) of a free space optical (FSO) system using polarization shift keying (POLSK) modulation under EW atmosphere turbulence model is derived. Then the effects of aperture averaging under different turbulence conditions described by the EW distribution are numerically studied with computer simulation, and the average BER of POLSK modulated system is compared with that of an on-off-keying (OOK) system. Numerical results show the effects of aperture averaging on the average BER under different turbulence strengths. The POLSK modulated FSO systems can offer better BER performance compared to OOK scheme.
关键词： average bit error rate,exponentiated Weibull distribution(EW),Polarization shift keying modulation(POLSK),aperture averaging,on-off-keying (OOK)
更新于2025-09-12 10:27:22
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[IEEE 2019 IEEE 12th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED) - Toulouse, France (2019.8.27-2019.8.30)] 2019 IEEE 12th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (SDEMPED) - Parametric degradation model of OLED using Design of Experiments (DoE)
摘要： This article presents an original parametric degradation model using Design of Experiments. This method is based on the estimation of a Weibull function under accelerated conditions. It is applied on cold white organic light emitting diodes OLEDs from Philips with a 10000 hrs theoretical lifetime. Accelerated degradation using thermal and electrical stress is tested. The predicted degrading model is a function of time, temperature, current density and their interaction. It illustrates the behaviour of the degradation of the OLED using multiple stress factors without really knowing the physics of these degradations. The proposed model is tested on experimental data for different luminances. The average error of the predicted model compared to real values is around 3 %. The proposed model is then compared to a previously developed lifespan model. The results obtained with the present approach are closer to the real values.
关键词： Degradation,Electrical stresses,Modeling,Thermal stresses,Design for Experiments,Accelerated aging,Organic light emitting diodes,Weibull distribution,Lifetime estimation
更新于2025-09-12 10:27:22