http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
정용현(Yonghyun Chung),이은석(Eunseok Lee),설우석(Wooseok Seol),양창환(Changhwan Yang),김우겸(Wookyum Kim) 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.5
케로신과 액체산소를 사용하는 액체로켓엔진은 극저온 영역과 고온의 연소가스 영역이 공존하게 된다. 전기부품을 포함한 엔진의 각 부품의 원활한 작동을 위해서는 단열재가 적절하게 엔진에 적용되어야 한다. 본 연구에서는 이러한 액체로켓엔진의 단열재 적용방안에 대해 세단계로 나누어 고찰하였다. 첫 번째로 고온및 극저온 부품을 정의하고 영역의 온도장을 해석하는 것이다. 두 번째는 각 부품 간을 연결해주는 배관 등의 연결부품에 대한 열전달 해석을 수행한다. 세 번째로 이러한 열전달 해석을 근거로 단열기준을 설정하여 적절한 온도분포가 형성되도록 단열재를 선정하고 적용하는 것이다. 본 논문에서는 이러한 적용방안에 대한 해외사례를 고찰하고 각 단계별로 단열재 적용방안을 마련해 본다. Liquid Rocket Engine is generally composed of extremely low and high temperature field. So that the component works properly including the electric component, the heat insulator should be applied appropriately. There are three steps. First, the heat source components should be defined and temperature field analyzed. Second, the heat transfer of pipes between the heat sources should be analyzed. Third, the components and pipes before and after applying the heat insulator should be analyzed. Finally, the optimized heat insulator depth can be calculated. In this paper, the procedure of this steps is established and investigated.
마우스의 기도 내 점적을 통한 가습기살균제 CMIT/MIT와 사망 간의 원인적 연관성에 관한 연구
김하영(Hayoung Kim),정용현(Yonghyun Chung),박영철(Yeongchul Park) 한국환경보건학회 2017 한국환경보건학회지 Vol.43 No.4
Objectives: The deaths of Korean victims exposed to the disinfectant CMIT/MIT have remained unresolved. This is mainly due to a lack of concordance between the few available toxicity tests and the abundant epidemiological data, making it difficult to establish a cause-and-effect relationship. Therefore, this study was carried out to investigate any potential associations between CMIT/MIT exposure and death. Methods: Groups of experimental and control C57BL/6 mice were instilled (in the trachea) with chloromethylisothiazolinone/methylisothiazolinone (CMIT/MIT) using a visual instillobot. CMIT/MIT was instilled over a period of three days and eight weeks, respectively, to achieve acute and chronic exposures. A threshold dose-response model was applied for estimating the threshold level as one line of evidence for a causal association between CMIT/MIT and death. Results: An acute exposure of 1.2 mg ai/kg/day of CMIT/MIT was estimated to reflect the threshold for death. The dose-response curve with this threshold showed a very steep slope and a narrow range of CMIT/MIT exposures. The narrow range of CMIT/MIT exposures, in particular, indicated an evident boundary between survival and death, thus implicating a strong causal association. A similar threshold dose-response relationship observed following acute exposure was also seen following chronic exposure to CMIT/MIT. Airborne disinfectant exposure was visible as minimal or mild lung damage with no fibrosis, as shown by histopathological tests. However, many observations are considered to be functional respiratory tract or lung failure due to death, as observed in necropsies of the mice that died due to CMIT/MIT exposures. Conclusions: There are two strong lines of evidence for a causal association between death and CMIT/MIT exposure: 1) The threshold dose-response curve, with a very steep slope and a narrow range of CMIT/MIT exposures showing a visible boundary between survival and death; and 2) many cases of functional respiratory or lung failure.
무인항공기 및 다중분광센서를 이용한 하천부유쓰레기 탐지 기법 연구
김흥민,윤홍주,장선웅,정용현,Kim, Heung-Min,Yoon, HongJoo,Jang, SeonWoong,Chung, YongHyun 대한원격탐사학회 2017 大韓遠隔探査學會誌 Vol.33 No.5
본 연구는 무인항공기 및 다중분광센서를 이용한 부유쓰레기 탐지 알고리즘을 개발하고자 하였다. 또한 알고리즘을 적용하여 하천의 부유쓰레기 발생 범위를 산정하였다. 부유쓰레기 탐지 구간을 대상으로 무인항공기를 이용한 항공촬영을 통해 면적 계산이 가능한 정사영상을 생성하였으며, 분광조사를 수행하여 하천수, 스티로폼, 초목류 등의 분광학적 특성을 이용한 부유쓰레기 탐지 지수식을 산출하였다. 그리고 산출된 지수식을 이용한 센서의 밴드 조합을 통해 스티로폼을 비롯한 부유쓰레기를 탐지하였다. 탐지 지수식 적용 결과 정사영상 내 총 3지점에서 대량의 부유쓰레기 집적 구간이 확인되었으며, 탐지 대상 면적 중 집적구간을 포함한 3.6%에 해당하는 0.82 ha($8,200m^2$)에서 스티로폼과 초목류를 포함한 대량의 부유쓰레기가 발생한 것으로 추정되었다. This study aims to develop the floating debris detection algorithm using a Unmanned Aerial Vehicle (UAV) and multispectral sensors. In addition, the occurrence range of floating debris was estimated by applying the algorithm. An aerial photograph using an unmanned aerial vehicle was used to generate an orthoimage that can calculate the area. A spectrum survey of water, plants litter, polystyrene foam etc. was conducted. After obtaining spectroscopic characteristics of floating debris and water, the River Floating Debris (RFD) index was calculated. And we detected the floating debris through band combination of sensor using RFD. As a result of the RFD application, accumulation zone of floating debris was confirmed at three sites in the orthoimage. It was estimated that a lot of floating debris was accumulated at 0.82 ha ($8,200m^2$), which is corresponding to 3.6% including the accumulation zone.
경유의 황성분이 SiC 매연저감장치의 성능에 미치는 영향
정건우(Gunwoo Jeong),강정호(Jeongho Kang),여아영(Ahyoung Yeo),정재우(Jae-Woo Chung),윤영훈(Younghun Yoon),정용현(Yonghyun Jeong),조재득(Jaedeug Jo),유영환(Younghwan You) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
Nowaday, Many country have been using many kind of DPF system. But reduction efficiency was decrease when using less than 430ppm sulfur contents diesel fuel used for a long time. Because sulfur poisoning. Therefore, It was hard to using for diesel fuel. some country using less than 430ppm sulfur contents diesel fuel. In this paper was studied for endurable SiC filter of sulfur poisoning. Because Reduction efficiency decrease Occurs. due to sulfur contents Because low sulfur diesel used for a long time. than uses 30ppm of sulfur contents in Constraints on. Need to be developed. In order to export to foreign countries for consumption will occur So I need to be developed to sulfur poisoning resistant SiC filter. Properties were examined for Sulfur poisoning by dynamometer durability Test. As the result. Reduction efficiency was found that many were not different. to Emissions and particulate matter. Reduction efficiency changes depending on the amount of coating. Suggested the possibility to filter development.
양전자 방출 단층 영상장치의 시스템 구조 및 촬영대상에 특화된 반복적 사이노그램 공백 보간 방법
김광돈(Kwangdon Kim),이기성(Kisung Lee),이학재(Hakjae Lee),정용현(Yonghyun Chung),주성관(Sungkwan Joo) 대한전자공학회 2016 대한전자공학회 학술대회 Vol.2016 No.6
Various geometries have been used to develop the positron emission tomography (PET) scanner in order to improve PET image resolution, and to detect events with higher sensitivity. However, the blind zones or inter-detector gaps for each detector block result in various artifacts and image distortions in reconstruction images. To compensate for this distortion, the literature offers several gap-filling methods, such as linear interpolation methods and iterative gap-filling methods. Uygar Tuna et al. proposed a novel gap-filling algorithm that shows superior gap-filling results, which can be attributed to the PET scanner geometry. However, the algorithm is not dedicated to imaging objects, and should be manually optimized for these objects. We aim to develop a gap-filling algorithm, in particular the filter mask design method of the algorithm, which optimizes the filter to the imaging object by an adaptive and iterative process, rather than by manual means. We generated the data set with two analytic phantom studies, Shepp-Logan and Jaszczak. The proposed algorithm shows results that compare to those of the manually optimized discrete-cosine transform 2 (DCT2) algorithm without perfect or full information of the imaging object, and improve the image quality of the reconstructed image.