• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.467-468
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• 2016

국내 가정용 태양광인버터의 주류는 3kW급으로 그린홈 보급사업, 태양광 대여사업 및 자가 설치 사업 등에서 사용되고 있다. 당사에서 효율향상 및 전력밀도 향상의 목표로 개발하여 2016년도 출시한 태양광인버터의 특징 및 태양광인버터 개발에 있어 추가적인 고려요소를 소개한다.

• 한국전산유체공학회지
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• 제19권4호
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• pp.8-13
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• 2014

A series of numerical simulation has been carried out to study performance of a cyclone type oil separator, which is designed for the compressor of a refrigeration system. Working fluid is R22, which is a typical refrigerant, and mineral oil droplet is supplied. Pitch of the helix is considered as design parameters to make a compact separator. Depending on the helix pitch, separation efficiency varies from 97.5 to 99%, while predicted pressure drop ranges from 5 to 6.5 kPa. Considering both of the pressure drop and separation efficiency, helix pitch of the separator has been designed as 50 mm.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.248-251
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• 2005

Graphite reinforced conductive polymer composites for PEMFC bipolar plates were fabricated by the compression molding technique. Graphite powder was mixed with an phenol resin to impart electrical property in composites. In this study, conductive polymer composites with high filler $loadings(>60wt.\%)$ were manufactured to accomplish high electrical conductivity above 100S/cm. The level of compaction is important because graphite powder increase electrical conductivity of composites by direct physical contact between particles. The optimum molding pressure according to filler was proposed experimentally. Various tests(electrical conductivity, flexural strength, compressive strength, leach test, etc) were carried out to verify the performance of fabricated composites for PEMFC bipolar plates. Fabricated composites have good electrical conductivity and mechanical strength. The results of leach test and contact angle measurement showed similar characteristics compared with commercial bipolar plates.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2004년도 추계학술발표대회논문집 제23권 2호
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• pp.421-424
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• 2004

한국 동해시 연안역에서 2001년 6월, 2003년 5월 및 2004년 5월 해상실험 및 실시간 모니터링 부이 시스템을 통해 수집된 해양관측(수온, 유속)자료와 SAR (Synthetic Aperture Radar)위성영상을 분석한 내부파의 물리적 특성을 정리하였다. 이를 토대로 음파전달 모델(RAM)을 통해 내부파에 의한 음파전달 영향을 파악하고, 음도파관 불변 이른(Waveguide invariant theory)을 적용하여 내부파에 의한 해양 변동성을 음향학적으로 정량화 하였다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2004년도 추계학술발표대회논문집 제23권 2호
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• pp.381-384
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• 2004

본 논문은 천해에서의 전구 음원 특성 연구를 수행하였다. 일반적으로 전구 음원의 특성은 수심에 따라 달라지며, 크기와 같은 물리적인 요인에 의해서도 달라지는 것으로 알려져 있다. 최근 전구 음원의 저주파 광대역 음원로써의 사용 가능성에 관한 연구가 수행되고 있다. 본 연구에서는 해상 실험 자료 분석을 통해 전구 음원 특성을 분석하였으며, 연구 결과 전구 음원이 천해에서 저주파 광대역 음원으로써 사용 가능함을 확인하였다.

• 전기학회논문지
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• 제65권10호
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• pp.1633-1638
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• 2016

Loop system arrangement in the primary distribution system has been increased for higher reliability of power supply to the customer. This paper presents a new fault calculation method for the loop structured unbalanced distribution feeders. Mathematical modeling method of the distribution system and superposition principal based fault calculation procedures are provided. In order to establish feasibility of the proposed method, various case studies have been performed using Matlab power system toolbox.

• 전기학회논문지
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• 제66권10호
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• pp.1460-1465
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• 2017

Outage areas can be transferred to adjacent feeders to restore power supply in case of the fault on the distribution system. Feeders in the small island or mountain area may not have backup feeders due to the low density of load. In this weakly meshed open loop system, BESS can be used as a backup feeder to improve reliability of power supply. This paper proposes a new network reconfiguration method for BESS based service restoration. Fuzzy decision making technique is adopted to deal with fuzziness of service restoration planning rules. Case studies using KEPCO real distribution system have been performed to verify feasibility of the proposed method.

• Journal of Nutrition and Health
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• 제50권6호
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• pp.595-602
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• 2017

Purpose: Malnutrition is a major concern in patients with gynecologic cancer receiving chemotherapy. The aim of this study was to evaluate the prognostic significance of malnutrition in patients with gynecologic cancer undergoing chemotherapy. Methods: A prospective, observational study was conducted on a total of 99 subjects who were treated at a tertiary hospital in Korea. Data regarding demographic, clinical, nutritional, and psychological characteristics at baseline and survival were obtained. Results: Performance status, nutritional status, depression, and annual income were significantly different between survivors and non-survivors. Multivariate Cox modeling after adjusting for other factors showed that a malnourished status in patients with gynecologic cancer undergoing chemotherapy was a significant and independent negative influencing factor for survival. Conclusion: These findings provide evidence that adequate nutritional assessment and intervention may assist in improving survival in patients with gynecologic cancer undergoing chemotherapy.

• 조명전기설비학회논문지
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• 제29권7호
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• pp.14-21
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• 2015

Distribution systems are operated in radial structure, but temporal loop structure could be founded the live load transfer. Main purposes of reconfiguration of distribution network are load balancing, loss minimization and voltage drop maintaining. In the loop structure, huge loop current can be flowed between two substations in case of large voltage angle difference. Protection devices of distribution line can be triped by this huge loop current. So, precise calculation of loop current is very important for secure switching. This paper proposes a novel calculation method of loop current using the voltage angle differences measured at the tie switches. Feasibility of the propose method has been verified by various case studies based on Matlab simulation.

• 한국초등과학교육학회지:초등과학교육
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• 제39권2호
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• pp.204-218
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• 2020

This study aims to investigate the representation patterns used by elementary teachers and their meaning-making process in electromagnetic experiments. In particular, we analyzed the representations depending on three levels of their abstractness: enactive representation (action based), iconic representation (image based) and symbolic representation (language based). For this, four experiment activities of two teachers were analyzed and the results are as follows. First, as an overall pattern of representation, an experiment subject is presented as the form of symbolic representation and the related concepts, experimental materials and methods are embodied through iconic representation. Then, through enactive representation, the actual experiments are implemented. The experimental results are primarily recorded through iconic representations and abstracted into symbolic representations to draw conclusions. The different levels of representations complement each other to expand their meanings, however, sometimes they also make inconsistent meanings among different levels. Based on these results, educational implications were discussed in terms of supporting and improving electromagnetic experiment activities.