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

Thermo-mechanical analysis on 10 kV SiC-MOSFETs to improve the reliability of solder layers

The study clarifies the thermo-mechanical characteristics of 10 kV SiC-MOSFET power modules to optimize die structures to improve their solder layer reliability The 10 kV SiC-MOSFET die is 8.1 mm square in size with 500 um thickness. As a reliability evaluation, a power cycle test (PCT) at a temperature swing 100 degC was performed on 10 kV and 3.3 kV SiC-MOSFETs, which differ in die size, thickness, and die edge width. Both samples failed in the solder layer under the die. A number of cycles to failure Nf of 3.3 kV, which has a shorter edge, was 30% compared to 10 kV. This Nf difference matched the calculated Nf based on plastic strain changes per cycle ɛ from 3D simulations. 3D simulations with various models indicate that the larger edge of SiC-MOSFETs, such as 10 kV, have higher solder lifetimes because the large temperature distribution of the die makes smaller solder temperature swings dT(solder). As an investigation of the influence of 10 kV SiC-MOSFET die structures, reducing the die thickness with the rectangular die shape was improved Nf by up to 3.5 times by halving ɛ. These results contribute to achieving an efficient digital design through thermo-mechanical simulations

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

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.Version of Recor

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

The Specialties Expected of Nurses by the Nursery School's Staff : Based on the Role of the Child Health Nursing Insupporting the Health of Children in Nursery School

保育施設における子どもの健康問題について,看護師にどのような専門性が期待されているかを明らかにすることを目的とし,2010年5 ～ 7月,愛知県内の44施設で働く保育士634名を対象に自由記載での自記式質問紙調査を実施した。対象者262名(回収率41.3%)であり,保育所看護師配置状況は「いない」とした者が208名(79.4%),配置希望者は197名(75.2%)であった。期待する専門性は,【園児の健康管理における判断と対応】,【看護師配置による安心】,【施設の安全管理と連携】,【保護者への対応】,【園児の健康管理における指導】,【保育士のメンタルサポート】の6つに類型化された。その結果,保育所看護師は数が少なく,配置の不均衡が示されるとともに,期待される存在であるが,多岐に及ぶ役割を明確に示し,普及と専門職としての連携が必要であると考えられた。This study aims to describe about the specialties expected of nurses by the nursery school’s staff related to the health problems. From May to July 2010, we used self-administered investigation for the 634nursery school's staff (working by 44 facilities) in Aichi Prefecture. The numbers of the analysis was 262 (recovery rate 41.3%). Two hundred eight (79.4%) staff answered non nurses in their nursery school and 194 (75.2%) staff demanded nurse's assignment. They expected the nurses specialties in 6 categories as "Judgement and action in health management of children", "Reassurance by assignment of nurses”, "Safety control and Collaborations in school”, "Parental support", "Instruction of health management for children", "mental support for nursery school's staff . The results of this study show that the school’s nurse were few, and there were some disproportion. They were expected existence ； however, it is important to show the role of coming to a variety clearly with spread and collaborateas professionals.journal articl