• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.143-144
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• 2014

The demand of diesel engine on the construction equipment has been rapidly increased because of thermal efficiency and power. But some of the construction equipment is imported from other country, since the their demands are not so large as compared with the other construction equipment. The imported construction equipments will be tested for emission with standard measurement mode. This study was conducted to measure emission characteristics of the construction equipment with changed standard measurement experimentally.

• Structural Engineering and Mechanics
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• 제57권2호
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• pp.369-387
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• 2016

In this work, random homogenization analysis for the effective thermal properties of a three-dimensional composite material with unidirectional fibers is presented by combining the equivalent inclusion method with Random Factor Method (RFM). The randomness of the micro-structural morphology and constituent material properties as well as the correlation among these random parameters are completely accounted for, and stochastic effective thermal properties as thermal expansion coefficients as well as their correlation are then sought. Results from the RFM and the Monte-Carlo Method (MCM) are compared. The impact of randomness and correlation of the micro-structural parameters on the random homogenized results is revealed by two methods simultaneously, and some important conclusions are obtained.

• 한국항공우주학회지
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• 제43권1호
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• pp.33-39
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• 2015

본 논문은 램프의 수명저하 없이 $1,000^{\circ}C$이상의 초고온 급속가열 환경을 지속적으로 모사할 수 있고 기존 사용해온 열하중 부가장치 대비 내구성과 신뢰성이 향상된 열하중 부가장치를 개발하여 초고속 비행체 날개의 구조 건전성 평가에 적용, 그 활용가능성을 수록한 내용이다. 본 시험을 통하여 초고온의 운용환경에 노출되는 비행체 날개의 공력가열에 의한 강성저하를 정량적으로 예측할 수 있었으며, 향후 비약적인 증가추세에 있는 공력가열온도를 경험하게 되는 극초음속 비행체에 대한 고온환경에서의 구조 강도특성 평가가 가능해짐으로써 시험 신뢰성 향상과 함께 고온구조강도시험 수행능력을 한 단계 도약시킬 수 있는 계기가 되었다.

• Journal of Power Electronics
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• 제16권2호
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• pp.685-694
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• 2016

This paper presents a reliability assessment model for the power semiconductors used in wind turbine power converters. In this study, the thermal loadings at different timescales of wind speed are considered. First, in order to address the influence of long-term thermal cycling caused by variations in wind speed, the power converter operation state is partitioned into different phases in terms of average wind speed and wind turbulence. Therefore, the contributions can be considered separately. Then, in regards to the reliability assessment caused by short-term thermal cycling, the wind profile is converted to a wind speed distribution, and the contribution of different wind speeds to the final failure rate is accumulated. Finally, the reliability of an actual power converter semiconductor for a 2.5 MW wind turbine is assessed, and the failure rates induced by different timescale thermal behavior patterns are compared. The effects of various parameters such as cut-in, rated, cut-out wind speed on the failure rate of power devices are also analyzed based on the proposed model.

• 반도체디스플레이기술학회지
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• 제19권2호
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• pp.16-21
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• 2020

How accurately reproducible energy is delivered to the wafer in the process of making thin films using PE-CVD (Plasma enhanced chemical vapor deposition) during the semiconductor process. This is the most important technique, and most of the reaction on the wafer surface is made by thermal energy. In this study, we studied the method of monitoring the change of thermal energy transferred to the wafer surface by monitoring the temperature change according to the change of the thin film formed on the showerhead facing the wafer. Through this research, we could confirm the monitoring of wafer thin-film which is changed due to abnormal operation and accumulation of equipment, and we can expect improvement of semiconductor quality and yield through process reproducibility and equipment status by real-time monitoring of problem of deposition process equipment performance.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.957-963
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• 2014

Converter transformers play important roles in high-voltage direct current transmission systems. This paper presents experimental and analysis results of the combined electrical and thermal aging of oil-impregnated paper at pulsating DC voltages. Breakdown voltages and time-to-breakdown of oil-paper specimens were measured by using short-time and constant-stress tests. The breakdown characteristics of combined electrical and thermal aging on insulation system were discussed. According to the relationship between failure time and aging temperature, the two-parameter Weibull model was improved. On the basis of the competing risk algorithm and the improved Weibull model, the two factors failure model was calculated. And the influence of temperature in the insulation system has been analyzed. This model performs better than the two-parameter Weibull model when both time and temperature are considered as variables in estimating the lifetime of oil-paper insulation.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2018년도 공동국제학술발표회
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• pp.162-162
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• 2018

• 드라이브 ㆍ 컨트롤
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• 제16권1호
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• pp.59-61
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• 2019

• 한국인터넷방송통신학회논문지
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• 제19권6호
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• pp.9-13
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• 2019

본 논문에서는 IoT 기반 열상 센서와 영상 센서 일체형 IP CCTV 설계에 관하여 연구하였으며 Full HD IP 카메라 영상과 열상모듈에서 전송되어지는 열상 데이터를 동시에 인지하여 가공 및 전송 할 수 있는 모니터링 시스템에 사용할 수 있도록 하였다. 열상 센서에서 감지하는 신호를 디지털로 변환하여 영상에 중첩시켜 실제 주변 온도에 대한 정보를 영상과 함께 실시간 제공하고, 영상 카메라에 열상이 추가됨으로 온도 변화를 예측하여 기존 장비에서 불가능한 화재 예측이 가능하게 하였다. 따라서 열상 센서와 영상센서 일체형 감시 장비를 통하여 환경 모니터링 시스템에서 전송되는 온도 데이터와 영상 신호를 송신하여 모니터링 시스템에 적용 가능하도록 하였다.

• 한국항공우주학회지
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• 제42권9호
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• pp.789-794
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• 2014

정지궤도급 차세대 통신위성에 탑재될 디지털신호처리기에는 디지털 고속통신을 위한 FPGA가 사용된다. 적용된 FPGA는 높은 열소산량을 가지고 있으며, 이로 인한 접합온도의 상승은 부하경감 요구조건을 만족하기 어렵고 장비의 수명과 신뢰도 저하의 주요 원인이다. 지상과는 달리 우주환경에서의 전장품의 열제어는 대부분 열전도를 통하여 이루어지고 있다. CCGA 또는 BGA 형태의 FPGA는 인쇄회로기판에 장착되지만, 인쇄회로기판의 열전도율은 FPGA의 열제어에 효율적이지 못하다. FPGA의 열제어를 위하여 부품 리드와 하우징을 직접 연결하는 히트싱크를 제작하였으며, 우주인증레벨의 열진공시험을 통하여 그 성능을 확인하였다. 높은 전력소모량을 가진 FPGA는 우주환경에 적용하기 어려웠으나, 히트싱크를 적용함으로써 부하경감 온도 마진을 확보하였다.