A5101437873- GaN-based semiconductor devices and materials
- Engineering Applied Research
- Industrial Vision Systems and Defect Detection
- Surface Roughness and Optical Measurements
- Atomic and Subatomic Physics Research
- Optical Systems and Laser Technology
- Quantum optics and atomic interactions
- Impact of Light on Environment and Health
- Thin-Film Transistor Technologies
- Mechanical and Optical Resonators
- Advanced Measurement and Detection Methods
- Calibration and Measurement Techniques
- Organic Light-Emitting Diodes Research
- Statistical and numerical algorithms
- Reliability and Maintenance Optimization
- Mobile Agent-Based Network Management
- Landslides and related hazards
- Fault Detection and Control Systems
- Color Science and Applications
- Optical measurement and interference techniques
- Algorithms and Data Compression
- Advanced Statistical Methods and Models
- Geomechanics and Mining Engineering
- Advanced optical system design
- Electronic Packaging and Soldering Technologies
Chongqing University
2023-2024
Zhejiang Lab
2020-2021
Chinese Academy of Sciences
2015-2017
University of Chinese Academy of Sciences
2016-2017
Changchun Institute of Optics, Fine Mechanics and Physics
2015-2017
Yunnan Observatories
2007
Ordnance Engineering College
2002
St. Cloud State University
2001
Although the predicted lifetime of classical 6000 h test given by Energy Star is taken as normal LED products in most research and applications, aim this study to explore error prediction lamps based on test. A non-accelerated aging with 10 conducted for 20,000 (from March 2016 now) under room temperature, which long enough kind lamp reaching real normalized luminous flux dropping 70% naturally. At different periods, correspondent each sample lumen degradation, median τ0.5 samples obtained...
The lumen degradation of LED lamps undergoing an accelerated aging test is investigated. entire lamp divided into three subsystems, namely, driver, lampshade, and light source. parameters output power [Watts (W)], transmittance (%), flux (lm) are adopted in the analysis source, respectively. Two groups aged under ambient temperatures 25°C 85°C, respectively, with time 2000 h. from 3.8% to 4.9% for group a temperature 10.6% 12.7% 85°C. source most aggressive part which accounts 70.5% on...
In this paper, the step-down aging test for light-emitting diode (LED) lamps is designed according to stopping rule of IESTM-28 standard and experimental data. The experiment under temperature stresses 90 °C, 80 70 60 from which temperatures two-step-down are selected. A Nelson model used calculate equivalent time one another, a two-stage method adopted establish reliability LED accelerated temperature. Then, lifetime at ambient 25 °C deduced by use Arrhenius model. It shown that best...
An accelerated aging test is the main method in evaluation of reliability light-emitting diodes (LEDs), and first goal this study to investigate how junction temperature (Tj) LED varies during aging. The Tj measured by forward voltage shows an upward trend over time, which gives a variation about 6°C-8°C after 3,000 h under ambient 80°C. second affects lifetime estimation. It verified that at certain stage, as increases, normalized luminous flux linearly decreases with rate microns (μ)...
Accelerated aging tests are the main method used in evaluation of LED reliability, and can be performed either online or offline modes. The goal this study is to provide difference between two test In experiments, sample attached different heat sinks acquire optical parameters under junction temperatures LEDs. By measuring temperature process (Tj1), testing (Tj2), we achieve consistency with an Tj1 Tj2 a Tj2. Experimental results show that degradation rate luminous flux rises as increases,...
In order to investigate the difference of lifetime predictions between LED lamps and light source modules, different types accelerated aging tests have been done in this paper. The temperatures are 85 °C, 80 °C 60 for three tests, respectively. Luminous flux, as evaluation criteria degradation, is measured at temperatures. Fitted by exponential decay law luminous rate each sample acquired. Under condition Weibull distribution, two-stage method used solve degradation model calculate lifetimes...
The accelerated aging tests under electric stress for one type of LED lamp are conducted, and the differences between online offline degradation luminous flux studied in this paper. transformation two test modes is achieved with an adjustable AC voltage stabilized power source. Experimental results show that exponential fitting possesses a higher degree most lamps, rate by always lower than tests. Bayes estimation Weibull distribution used to calculate failure probabilities voltages, then...
This paper mainly introduces independent water account management system. system takes the comprehensive database as center, other subsystems develop round of database. Using development tool J2EE, charges, quota for proposed fare increase, price formulated such functions to be implemented.
In order to improve the precision and beam quality of a pump laser for spin exchange relaxation free inertial measurement device, we applied one scheme achieve square wave modulation power stability control another obtain uniform intensity distribution beam, in which acousto-optic modulator (AOM) proportion integration differentiation (PID) controller were used former, freeform surface lens was designed optimized latter based on TracePro software. experiments, first-order diffraction light...
In order to verify which of the distributions and established methods reliability model are more suitable for analysis accelerated aging LED lamp, three (approximate method, analytical method two-stage method) used analyze experimental data under condition Weibull distribution Lognormal distribution, in this paper. Ten lamps selected experiment luminous fluxes measured at an temperature. AIC information criterion is adopted evaluation models. The results show that accuracies higher than...
Due to installation errors, expansion and contraction of materials, or foundation settlement, GIS equipment is prone accidents such as cylinder cracks, support tilt gas leakage when the bellows are improperly deployed. Therefore, it great significance understand stress distribution characteristics its influencing factors for ensuring operation safety equipment. In this paper, field simulation research was carried out bellows, deformation displacement were solved, influence wall thickness...