Structure Based Compact Model for Output Capacitance of Trench Field-Plate MOSFET to Enable Power Loss Prediction

We propose a structure based compact model for out-put capacitance (Coss) of trench Field-Plate MOSFET. Ap-propriate equations were considered for Coss curves in three regions. Output charge (Qoss) and stored energy (Eoss) that were calculated by the proposed model corre-sponded very well to TCAD results. In assumption of 10 A and 2 MHz operation, conduction loss of 1.0 W and out-put charge loss of 1.26 W were estimated.2017 International Conference on Solid State Devices and Materials (SSDM2017), Sendai International Center, Sendai, Japan, September 19-22, 201

Formulation of Single Event Burnout Failure Rate for High Voltage Devices in Satellite Electrical Power System

Single-Event Burnout (SEB) is a catastrophic failure in the high voltage devices that is initiated by the passage of particles during turn-off state. Previous papers reported that SEB failure rate increases sharply when applied voltage exceeds a certain threshold voltage. On the other hand, the high voltage devices for the artificial satellite have been increasing. In space, due to increase flux of particle, it is predicted that SEB failure rate will be higher. In this paper, we proposed the failure rate calculation method for high voltage devices based on SEB cross section and flux of particles. This formula can calculate the failure rate at space level and terrestrial level depending on the applied voltage of the high voltage devices.2017 29th International Symposium on Power Semiconductor Devices and IC\u27s (ISPSD), May 28 2017-June 1 2017, Sapporo, Japa

Thermal Degradation Behavior of Poly(Lactic Acid) in a Blend with Polyethylene

Poly(L-lactic acid) (PLLA) is a candidate for feedstock recycling materials, because it easily depolymerizes back into the cyclic monomer, L,L-lactide. To examine the recycling of PLLA from blends with other kinds of polymers, a polymer blend of PLLA and linear low-density polyethylene (LLDPE) was prepared and thermally degraded with a degradation catalyst: magnesium oxide (MgO) in a thermogravimeter/differential thermal analyzer (TG/DTA) and pyrolysis-gas chromatograph/mass spectrometer (Py-GC/MS). To clarify the influence of the LLDPE ingredient in the blend, the thermal degradation data were analyzed kinetically using two simulation methods: integration and random degradation analytical methods. From the results, it was found that PLLA was effectively depolymerized in the presence of MgO into L,L-lactide with a low racemization ratio and that LLDPE had no effect on the feedstock recycling of PLLA

Structure-based capacitance modeling and power loss analysis for the latest high-performance slant field-plate trench MOSFET

Field-plate trench MOSFETs (FP-MOSFETs), with the features of ultralow on-resistance and very low gate–drain charge, are currently the mainstream of high-performance applications and their advancement is continuing as low-voltage silicon power devices. However, owing to their structure, their output capacitance (Coss), which leads to main power loss, remains to be a problem, especially in megahertz switching. In this study, we propose a structure-based capacitance model of FP-MOSFETs for calculating power loss easily under various conditions. Appropriate equations were modeled for Coss curves as three divided components. Output charge (Qoss) and stored energy (Eoss) that were calculated using the model corresponded well to technology computer-aided design (TCAD) simulation, and we validated the accuracy of the model quantitatively. In the power loss analysis of FP-MOSFETs, turn-off loss was sufficiently suppressed, however, mainly Qoss loss increased depending on switching frequency. This analysis reveals that Qoss may become a significant issue in next-generation high-efficiency FP-MOSFETs

Reductions of docosahexaenoic acid-containing phosphatidylcholine levels in the anterior horn of an ALS mouse model

AbstractIn this study, we analyzed the spatiotemporal alterations of phospholipid composition in the spinal cord of an amyotrophic lateral sclerosis (ALS) mouse model (G93A-mutated human superoxide dismutase 1 transgenic mice [SOD1G93A mice]) using imaging mass spectrometry (IMS), a powerful method to visualize spatial distributions of various types of molecules in situ. Using this technique, we deciphered the phospholipid distribution in the pre-symptomatic stage, early stage after disease onset, and terminal stages of disease in female SOD1G93A mouse spinal cords. These experiments revealed a significant decrease in levels of docosahexaenoic acid (DHA)-containing phosphatidylcholines (PCs), such as PC (diacyl-16:0/22:6), PC (diacyl-18:0/22:6), and PC (diacyl-18:1/22:6) in the L5 anterior horns of terminal stage (22-week-old) SOD1G93A mice. The reduction in PC (diacyl-16:0/22:6) level could be reflecting the loss of motor neurons themselves in the anterior horn of the spinal cord in ALS model mice. In contrast, other PCs, such as PC (diacyl-16:0/16:0), were observed specifically in the L5 dorsal horn gray matter, and their levels did not vary between ALS model mice and controls. Thus, our study showed a significant decrease in DHA-containing PCs, but not other PCs, in the terminal stage of ALS in model mice, which is likely to be a reflection of neuronal loss in the anterior horns of the spinal cords. Given its enrichment in dorsal sensory regions, the preservation of PC (diacyl-16:0/16:0) may be the result of spinal sensory neurons being unaffected in ALS. Taken together, these findings suggest that ALS spinal cords show significant alterations in PC metabolism only at the terminal stage of the disease, and that these changes are confined to specific anatomical regions and cell types

Arachidonic acid containing phosphatidylcholine increases due to microglial activation in ipsilateral spinal dorsal horn following spared sciatic nerve injury

Peripheral nerve injury induces substantial molecular changes in the somatosensory system that leads to maladaptive plasticity and cause neuropathic pain. Understanding the molecular pathways responsible for the development of neuropathic pain is essential to the development of novel rationally designed therapeutics. Although lipids make up to half of the dry weight of the spinal cord, their relation with the development of neuropathic pain is poorly understood. We aimed to elucidate the regulation of spinal lipids in response to neuropathic peripheral nerve injury in mice by utilizing matrix-assisted laser desorption/ionization imaging mass spectrometry, which allows visualization of lipid distribution within the cord. We found that arachidonic acid (AA) containing [PC(diacyl-16:0/20:4)+K]+ was increased temporarily at superficial ipsilateral dorsal horn seven days after spared nerve injury (SNI). The spatiotemporal changes in lipid concentration resembled microglia activation as defined by ionized calcium binding adaptor molecule 1 (Iba1) immunohistochemistry. Suppression of microglial function through minocycline administration resulted in attenuation of hypersensitivity and reduces [PC(diacyl-16:0/20:4)+K]+ elevation in the spinal dorsal horn. These data suggested that AA containing [PC(diacyl-16:0/20:4)+K]+ is related to hypersensitivity evoked by SNI and implicate microglial cell activation in this lipid production

A System for Worldwide COVID-19 Information Aggregation

The global pandemic of COVID-19 has made the public pay close attention to related news, covering various domains, such as sanitation, treatment, and effects on education. Meanwhile, the COVID-19 condition is very different among the countries (e.g., policies and development of the epidemic), and thus citizens would be interested in news in foreign countries. We build a system for worldwide COVID-19 information aggregation (http://lotus.kuee.kyoto-u.ac.jp/NLPforCOVID-19 ) containing reliable articles from 10 regions in 7 languages sorted by topics for Japanese citizens. Our reliable COVID-19 related website dataset collected through crowdsourcing ensures the quality of the articles. A neural machine translation module translates articles in other languages into Japanese. A BERT-based topic-classifier trained on an article-topic pair dataset helps users find their interested information efficiently by putting articles into different categories.Comment: Poster on NLP COVID-19 Workshop at ACL 2020, 4 pages, 3 figures, 7 table

Self-Turn-on-Free 5V Gate Driving for 1200V Scaled IGBT

Negative biasing of the gate voltage in a scaled insulated gate bipolar transistor (IGBT) during the off-state was modeled and found to be effective against self-turn-on failures. The required self-turn-on-free criteria were verified experimentally.31st IEEE International Symposium on Power Semiconductor Devices and ICs (ISPSD 2019), 19-23 May 2019, Shanghai, Chin