- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Las Vegas, NV, USA (2019.5.28-2019.5.31)] 2019 IEEE 69th Electronic Components and Technology Conference (ECTC) - Assessment of Accelerometer Versus LASER for Board Level Vibration Measurements
摘要： The ongoing trend to deploy ICs in more complex and harsher applications, entails precise evaluation of solder joint reliability of components subjected to vibration loads. For this, a good understanding of the PCB vibrational motion during a board level vibration test is essential. This can only be achieved by a well characterized vibration test setup. The vibration motion can be recorded by using a contact-based measurement approach, using an accelerometer, or a contactless measurement configuration, i.e. using a Laser Doppler Vibrometer (LDV). This paper evaluates both measurement techniques by recording the PCB dynamic response, i.e. the resonance frequency and peak-to-peak displacement, in a board level vibration test set up. Bare and assembled printed circuit boards (PCBs) are investigated using different PCB form factors and package outlines (Wafer Level Chip Scale Package (WLCSP) and Ball Grid Array (BGA)), showing that LDV enables better lateral resolution and a more accurate measurement solution. Especially when the weight of the accelerometer cannot be neglected compared to the weight of the component on the PCB. An accelerometer is shown to perturb the PCB vibration motion. It is found that depending upon the test objectives and PCB electronic system involved, both techniques can be used as complementary to one another. The accelerometer weight may give rise to substantial modification of vibration response which can be used to simulate the presence of a component on a bare PCB. In addition, both methods are expected to recognize the same trends when e.g. studying the environmental impact during vibration tests. Finally, the experimental observations are also confirmed using a Finite Element Model (FEM).
关键词： board level reliability,LASER Doppler Vibrometer,Wafer Level Chip Scale Package,vibration test,modal analysis,PCB dynamic response
更新于2025-09-11 14:15:04
-
Imaging and micro-structural characterization of moisture induced degradation in crystalline silicon photovoltaic modules
摘要： Moisture induced degradation in photovoltaic (PV) modules operate via multiple chemical mechanisms commonly identi?ed by the sole use of destructive techniques. However, in such cases, e?ective use of spatial imaging techniques can aid identi?cation of certain operating mechanisms on the basis of degradation pattern characteristics. This paper presents an approach of imaging the e?ects of moisture induced degradation in crystalline silicon PV modules under damp heat (DH) test conditions using electroluminescence (EL) and dark lock-in-thermography (DLIT) imaging techniques. The a?ected regions were extracted for identi?cation of degradation products using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) micro-structural characterization technique. Consequently, combination of both imaging and micro-structural characterization techniques were used to propose the mechanism of degradation. The presented approach was instrumental in identi?cation of the e?ects of moisture induced degradation through imaging techniques, moreover the investigation also provided insights in this ?eld of work. The results present signature image patterns for identi?cation and di?erentiation of dominant chemical mechanisms under moisture induced conditions viz. tin migration at the ?nger-wafer interface and formation of silver oxide at cell cracks and edges. The ribbon interconnects was identi?ed as an active site for deposition of oxides from solder material, and aluminium electrode in presence of water as an electrolyte. Moreover, loss in interfacial adhesion between wafer, encapsulant and ?nger. In addition, material quality, manufacturing distinctions, and module design parameters seem to be responsible for observing di?erent operating mechanisms. Also, the obtained insights were applied for investigation of a 20-year-old aged PV module.
关键词： Chemical degradation,Damp heat test,Photovoltaic modules,Electroluminescence imaging,Dark lock-in thermography imaging,Moisture induced degradation
更新于2025-09-11 14:15:04
-
[IEEE 2019 International Conference on Communications, Information System and Computer Engineering (CISCE) - Haikou, China (2019.7.5-2019.7.7)] 2019 International Conference on Communications, Information System and Computer Engineering (CISCE) - Remaining Useful Lifetime Prediction of Semiconductor Lasers Using Radiation-Induced Model and Particle Filtering Method
摘要： The main factor, which leads to semiconductor lasers degradation in space mission experiments, is the introduction of lattice defects in the detector material produced by radiation. Therefore, a new remaining useful life (RUL)prediction method considering radiation effect is presented. The prediction method is based on failure mechanisms and particle filters, which realizes the combination of a physical model and data-driven method. The particle filters can abundantly employ degradation data and avoid ignoring the failure mechanism. Accelerated degradation testing (ADT) is proposed for effectively assessing the proposed prediction method, in which the proton radiation is selected as the accelerated stress. The prediction results are compared with other methods to verify the accuracy and effectiveness of the proposed prediction method.
关键词： Particle filter,Remaining useful life,radiation effect,Physics of failure,Accelerated degradation test
更新于2025-09-11 14:15:04
-
Estimation on hazardous characteristics of the components from linear type of end-of-life light-emitting diode lamps
摘要： The supply of light-emitting diode (LED) lamps has been expanding as lighting devices to replace fluorescent lamps. Accordingly, it is expected that a large amount of end-of-life LED lamps will be generated. Among various types of LED lamps, liner LED lamps are generally used. Since linear LED lamps have been reported to use hazardous materials such as As and Pb, the hazardous characteristics of end-of-life LED lamps were estimated. To verify the hazardous characteristics of end-of-life linear LED lamps, leaching tests such as Korea Extraction Test (KET) and Toxicity Characteristics Leaching Procedure (TCLP) were carried out for the overall mixture and the each component of end-of-life linear LED lamps. The linear LED lamp is generally composed of cover, frame, LED, the driver and others. The portions of LED and the driver in linear LED lamp are only about 1% and 10%, respectively. End-of-life linear LED lamp can be non-hazardous waste because leaching concentrations of heavy metals in the overall mixture of end-of-life linear LED lamp were lower than the regulatory level. Since leaching concentrations of As, Pb and Cu in LED and the driver were higher than the regulatory level, however, LED and the driver can be classified as the hazardous waste.
关键词： Hazardous characteristic,LED,Toxicity characteristics leaching procedure (TCLP),Korea extraction test (KET)
更新于2025-09-11 14:15:04
-
Extended multiplicative signal correction for FTIR spectral quality test and pre‐processing of infrared imaging data
摘要： Spectral quality control is an important step in the analysis of infrared spectral data, however, often neglected in scientific literature. A frequently used quality test that was originally developed for infrared spectra of bacteria is provided by OPUS software from Bruker Optik GmbH. In this study the OPUS quality test is applied to a large number of spectra of bacteria, yeasts and moulds and hyperspectral images of microorganisms. It is shown that the use of strict thresholds for parameters of the OPUS quality test leads to discarding too many spectra. A strategy for optimizing parameters thresholds of the OPUS quality test is provided and a novel approach for spectral quality testing based on Extended Multiplicative Signal Correction (EMSC) is suggested. For all the data sets considered in our study, the EMSC quality test is shown to be the best among different alternatives of OPUS quality test provided.
关键词： Extended Multiplicative Signal Correction,infrared spectroscopy,spectral quality test
更新于2025-09-11 14:15:04
-
Performance evaluation and degradation assessment of crystalline silicon based photovoltaic rooftop technologies under outdoor conditions
摘要： Keeping track of ?eld performance and degradation rate of photovoltaic panels in regions with diverse environmental exposures is critical. The objective of this paper is to determine two and half year performance characteristics and degradation rate of poly-crystalline and heterojunction with intrinsic thin layer roof-top photovoltaic units under prevailing weather conditions in the Central Anatolia region. Degradation rates of the photovoltaic units were determined through analysing the effective peak power, and the temperature corrected performance ratio of each technology. Processing of the measured data covering the test period reveals that the thin ?lm technology offers lower degradation rate with nearly (cid:1)0.1% than the poly-crystalline based technology within the range of (cid:1)0.67% to (cid:1)0.83%, respectively. The study allows a better understanding of variations in performance and behaviour of the output power of poly-crystalline and heterojunction with intrinsic thin layer roof-top photovoltaic units after 2.5 years of outdoor exposure.
关键词： Degradation rate,Performance,Outdoor test,PV
更新于2025-09-11 14:15:04
-
[IEEE 2019 28th Wireless and Optical Communications Conference (WOCC) - Beijing, China (2019.5.9-2019.5.10)] 2019 28th Wireless and Optical Communications Conference (WOCC) - Relaxed Polar Codes under AWGN Channels with Low Complexity and Low Latency
摘要： In this paper, we demonstrate a wafer-level sorting test solution developed for quad-channel linear driver to be used in a 400G silicon photonics transceiver module. In-house built tester-on-a-board (TOB) system was used to provide power and control signals to the device-under-test (DUT), as well as conduct parametric tests. RF switch matrix was implemented to support multi-channel RF tests up to 50GHz. This wafer sorting test solution covers contact tests, power consumption tests, single-ended and true-mode differential full S-parameter tests, output signal swing and total harmonic tests. This work enables wafer-level driver die sorting capability for next-generation 400G silicon photonics coherent transceiver module.
关键词： wafer-level test,silicon photonics,transceiver module,driver die
更新于2025-09-11 14:15:04
-
Dynamically Tunable Plasmon-Induced Transparency Based on Radiative–Radiative-Coupling in a Terahertz Metal–Graphene Metamaterial
摘要： The thin aluminum liners with an aspect ratio R/?r (cid:28) 1 have been imploded on the primary test stand (PTS) facility, where R is the outer radius of the liner and ?r is the thickness. The x-ray self-emission images present azimuthally correlated perturbations in the liner implosions. The experiments show that at ?10 ns before the stagnation, the wavelengths of perturbation are about 0.93 mm and 1.67 mm for the small-radius and large-radius liners, respectively. We have utilized the resistive magnetohydrodynamic code PLUTO to study the development of magneto-Rayleigh–Taylor (MRT) instabilities under experimental conditions. The calculated perturbation amplitudes are consistent with the experimental observations very well. We have found that both mode coupling and long implosion distance are responsible for the more developed instabilities in the large-radius liner implosions.
关键词： Z-pinches,thin liner implosion,primary test stand (PTS),magneto-Rayleigh–Taylor instability,magnetohydrodynamic (MHD)
更新于2025-09-11 14:15:04
-
Experimental Investigation of the Ternary Ge-Sn-In and Ge-Sn-Zn Systems
摘要： This paper presents results of experimental examinations of alloys from the ternary Ge-Sn-In and Ge-Sn-Zn systems. Differential thermal analysis, scanning electron microscopy with energy dispersive spectroscopy and x-ray diffraction were used for the experimental investigation of the prepared samples. Obtained experimental results were compared with the thermodynamically extrapolated phase diagrams of the Ge-Sn-In and Ge-Sn-Zn ternary systems based on the thermodynamic parameters for the constitutive binary systems. A good agreement is seen, which suggests that it is not necessary to introduce new thermodynamic parameters for the ternary Ge-Sn-In and Ge-Sn-Zn systems. By using the proposed thermodynamic dataset, a liquidus projection and invariant reactions have been predicted for both investigated ternary systems.
关键词： phase diagrams,liquidus projection,experimental test
更新于2025-09-11 14:15:04
-
Feasibility of Macular Integrity Assessment (MAIA) Microperimetry in Children: Sensitivity, Reliability, and Fixation Stability in Healthy Observers
摘要： PURPOSE. To assess the feasibility of macular integrity assessment (MAIA) microperimetry (MP) in children. Also to establish representative outcome measures (differential light sensitivity, ?xation stability, test–retest reliability) for children without visual impairment. METHODS. Thirty-three adults and 33 children (9–12 years) were asked to perform three monocular MAIA examinations within a single session (dominant eye only). RESULTS. Children exhibited poorer test–retest reliability than adults for measures of both mean sensitivity (95% coef?cient of repeatability [CoR95] ? 2.7 vs. 2.3 dB, P ? 0.036) and pointwise sensitivity (CoR95 ? 6.2 vs. 5.7 dB, P < 0.001). Mean sensitivity was lower in children (27.6 vs. 29.5 dB, P < 0.001), and ?xation stability was poorer (95% bivariate contour ellipse area [BCEA95] ? 4.58 vs. 1.14, P < 0.001). Mean sensitivity was negatively correlated with ?xation stability (r ? (cid:2)0.44, P < 0.001). Both children and adults exhibited substantial practice effects, with mean sensitivity improving by 0.5 dB (adults) and 0.9 dB (children) between examinations 1 and 2 (P (cid:3) 0.017). There were no signi?cant differences between examinations 2 and 3 (P ? 0.374). CONCLUSIONS. Microperimetry is feasible in 9- to 12-year-old children. However, systematically lower sensitivities mean that the classi?cation boundary for "healthy" performance should be lowered in children, pending development of techniques to improve attentiveness/?xation that may reduce or remove this difference. High measurement variability suggests that the results of multiple tests should be averaged when possible. Learning effects are a potential confound, and it is recommended that the results of the ?rst examination be discarded.
关键词： test-retest reliability,MAIA,microperimetry,visual ?elds,differential light sensitivity,perimetry,children
更新于2025-09-11 14:15:04