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Real time degradation monitoring system for high power IGBT module under power cycling test
Get PDF24th European Symposium on Reliability of Electron Devices, Failure Physics and Analysis. Schedule, September 30-October 4, 2013, Venue, Arcachon, FranceA “real time” monitoring system which enables to observe internal degradation process to failure of power semiconductors under power cycling test is proposed. The system was realized by combining a scanning acoustic tomography (SAT/SAM), power stress controlling, device cooling, water jet system and chip temperature monitoring. Two contradictory problems, namely, electrically wiring for power cycling and waterproof of device for SAT imaging were compatible with each other by experimental setup with an original water tank. Self-heating of power devices was supressed by controlling temperature of water which is couplant of ultrasonic wave for the SAT. A demonstration of this system was performed by using an IGBT module which maximum rating of collector current was 400 A (DC)
Moisture Transport Model for Porous Media and Application to Food Drying(A Characteristics of Moisture Distributions in Food During Microwave Vacuum Drying)
No full textMoisture transport is an important phenomenon in many technological fields. We summarize a fundamental description method with use of the relative permeability and the moisture diffusion coefficient. The theoretical approach for the two-phase flow in the porous media is based on the extended Darcy model. The relative permeability and the moisture diffusion coefficient are functions of the moisture content and they express the effects of the friction loss and the capillary pressure, respectively. The model is applied to the microwave vacuum drying of food, where the vapor pressure drives the moisture from the inner to the outer because of the internal heating by the microwave irradiation. The numerical moisture-distributions are compared with the experimental results obtained by the MRI. It is shown that the microwave vacuum drying gives a desirable moisture-distribution for the drying.
Moisture transport is an important phenomenon in many technological fields. We summarize a fundamental description method with use of the relative permeability and the moisture diffusion coefficient. The theoretical approach for the two-phase flow in the porous media is based on the extended Darcy model. The relative permeability and the moisture diffusion coefficient are functions of the moisture content and they express the effects of the friction loss and the capillary pressure, respectively. The model is applied to the microwave vacuum drying of food, where the vapor pressure drives the moisture from the inner to the outer because of the internal heating by the microwave irradiation. The numerical moisture-distributions are compared with the experimental results obtained by the MRI. It is shown that the microwave vacuum drying gives a desirable moisture-distribution for the drying
Electrochemical Detection of Duplex DNA Using Intercalation-Triggered Decomplexation of Ferrocene with β-Cyclodextrin
Get PDFThe redox peak of ferrocenylnaphthalene diimide used as a threading intercalator shifted positively due to the formation of its complex with β-cyclodextrin. This complex collapsed upon the addition of double-stranded DNA, and its redox potential shifted negatively. This behavior was applied for the homogenous detection of a polymerase chain reaction (PCR) product from Porphyromonas gingivalis, which is important for the diagnosis of periodontal disease, and its quantitative detection was achieved with a detection limit of 2.7 nM
Semantic Characteristics Prediction of Pulmonary Nodule Using Artificial Neural Networks
Get PDFThe 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC'13), July 3-7, 2013, Osaka, JapanSince it is difficult to choose which computer calculated features are effective to predict the malignancy of pulmonary nodules, in this study, we add a semantic-level of Artificial Neural Networks (ANNs) structure to improve intuition of features selection. The works of this study include two: 1) seeking the relationships between computer-calculated features and medical semantic concepts which could be understood by human; 2) providing an objective assessment method to predict the malignancy from semantic characteristics. We used 60 thoracic CT scans collected from the Lung Image Database Consortium (LIDC) database, in which the suspicious lesions had been delineated and annotated by 4 radiologists independently. Corresponding to the two works of this study, correlation analysis experiment and agreement experiment were performed separately
Calculation of critical current in DC HTS cable using longitudinal magnetic field effect
Get PDFProceedings of the 25th International Symposium on Superconductivity (ISS 2012) Advances in Superconductivity XXV , December 3-5, 2012, TOWER HALL FUNABORI, Tokyo, JapanIt is known from experimental data that the critical current of superconducting wires in a longitudinal magnetic field is higher than that in a transverse magnetic field. This property was proposed to apply to DC superconducting cables in our previous paper. Here, we propose a new calculation method of the current-carrying capacity for a new DC superconducting cable. An iteration method is used to calculate the magnetic field and critical current density in each layer and the current-carrying capacity of the cable. This enables us to calculate these quantities even for the cable with a different structure from the force-free one. When the critical current density increases with a longitudinal magnetic field, the optimal structure is found to be close to that of the force free cable. The optimal structure is obtained also when the critical current density decreases slightly with the longitudinal magnetic field. The reason for the enhanced current-carrying capacity even for such a case is a sufficiently larger critical current density in the longitudinal magnetic field than that in the transverse magnetic field
THE EVALUATOR’S ASSESSMENT LEARNING USING STUDENT’S REPORT AT CLASSROOM
Get PDFThe Fourth International Conference on e-Learning (ICEL2013), July 8-10, 2013, VSB-Technical University of Ostrava, Czech RepublicIn this research, the learner learns from evaluator's assessment for another students report on collaborative evaluation. Our system (evPoints) relate to moodle, that enable to report posting and mutual evaluation. In this paper, we report total design about this research
Strain Rate Concentration Factor for Double-Edge-Notched Specimens Subjected to High Speed Tensile Loads
Get PDF13th International Conference on Fracture, June 16–21, 2013, Beijing, ChinaEngineering plastics provide superior performance to ordinary plastics for wide range of the use. For polymer materials, dynamic stress and strain rate may be major factors to be considered when the strength is evaluated. Recently, high speed tensile test is being recognized as a standard testing method to confirm the strength under dynamic loads. In this study, therefore, high speed tensile test is analyzed by the finite element method; then, the maximum dynamic stress and strain rate are discussed with varying the tensile speed and maximum forced displacement. The strain rate concentration factor found to be constant independent of tensile speed, which is defined Ktέ as the maximum strain rate appeared at the notch root over the average nominal strain rate at the minimum section. The maximum strain rate is controlled by the tensile speed alone independent of the magnitude of the forced displacement. It is found that the difference between static and dynamic maximum stress concentration (σmax-σst) at the notch root is proportional to the tensile speed when u/t≦5000mm/s
Stochastic Runge-Kutta methods with deterministic high order for ordinary differential equations
Get PDFstochastic Runge-Kutta (SRK) methods for non-commutative stochastic differential equations (SDEs). As a result, we have obtained weak second order SRK methods which have good properties with respect to not only practical errors but also mean square stability. In our stability analysis, as well as a scalar test equation with complex-valued parameters, we have used a multi-dimensional non-commutative test SDE. The performance of our new schemes will be shown through comparisons with an efficient and optimal weak second order scheme proposed by Debrabant and Rößler (Appl. Numer. Math. 59:582–594, 2009)