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Al-Si 도금된 보론강 레이저 소스에 따른 레이저 용접부의 미세조직과 기계적 성질에 미치는 핫스탬핑 처리의 영향
오명환,공종판,권민석,강정윤,Oh, Myeong-Hwan,Kong, Jong-Pan,Kwon, Min-Suck,Kang, Chung-Yun 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.6
In this study, the effect of laser source($CO_2$ and Nd:YAG) on the microstructure and tensile properties of laser welded Al-Si coated boron steel(1.2mmt) was investigated with before and after hot-stamping. In case of as welds condition, fracture occurred in base metal unrelated to the laser source. It could be explained that tensile strength of fusion zone composed of martensite and bainite is higher than that of base metal that contains a lot of ferrite despite dilution of Al and Si from coating layer to fusion zone. In case of hot-stamping condition, the fracture occurred in fusion zone irrelevant to laser source and the tensile strength was lower than hot stamped base metal. In the $CO_2$ laser welds, $Fe_3$(Al,Si) formed near the bond line was transformed into ferrite during hot-stamping. Therefore tensile strength of bond line is lower than that of base metal and center of fusion zone and the fracture occurred in the bond line. On the other hand, in the Nd:YAG laser welds, the higher concentration of Al formed the ferrite in the fusion zone during hot-stamping treatment. Also, the thickness of centerline was thinner than that of base metal. Therefore, it is considered that fracture occurred in centerline of fusion zone due to effect of concentration stress, and it leaded to a lower tensile strength and elongation.
심장질환 및 당뇨병의 재발 위험요인의 예측을 위한 SVM 기반 회귀분석의 성능비교
오명환(Myeong Hwan Oh),정용규(Yong Gyu Jung) 한국IT마케팅학회 2014 한국IT마케팅학회 학술대회 Vol.2014 No.1
Recently, as the Korean Digital equipment and technology develops, by analyzing the stored data, in order to provide my users know the new information, data mining techniques have been utilized. Data mining techniques are verified according to the purpose to be used, confirmation, discovered, are used for purposes such as prediction. In this paper, not only patients with no cardiovascular or coronary artery disease is blood sugar valued dye in the risk factors that provided, blood pressure, aspirin, to evaluate the risk of heart disease and diabetes to have a non smoking, and to predict the risk, that give us the user is desired, using a regression analysis. Regression analysis, are suitable for predictive analytics, you will be able to perform a variety of regression analysis. Typically there is an SVM-based regression analysis. SVM is analysis capability for performing error generalized in a direction to a minimum is evaluated as excellent. By analyzing the SVM-based regression and general multiple regression analysis to compare the performance SVM.
사군자추출분말(HU033)의 Quisqualic Acid 성분 분석법 검증
김명일(Myeong-Il Kim),윤지수(Ji-Soo Yoon),오명환(Myeong-Hwan Oh),손락호(Rak-Ho Son),연성흠(Sung-Hum Yeon) 한국식품영양과학회 2021 한국식품영양과학회지 Vol.50 No.2
사군자추출분말(HU033)을 식약처 건강기능식품 개별인정 원료로 개발하기 위한 연구의 일환으로 원료 표준화를 위해 지표성분인 quisqualic acid의 HPLC 분석법을 설정하였고 이에 대한 검증을 실시하였다. 그 결과 표준용액과 HU033의 HPLC 크로마토그램을 비교하여 다른 물질의 간섭 없이 피크가 선택적으로 분리되었으며, 표준용액과 HU033의 피크 머무름시간이 정확히 일치하는 것을 확인하였다. 또한 동일한 스펙트럼을 나타내는 것을 확인하여 본 시험법의 특이성을 확인하였다. 검량선의 상관계수(R2)는 모두 0.998 이상으로 높은 직선성을 확인하였고, 직선성의 검출한계는 0.976 ㎍/mL, 정량한계는 2.958 ㎍/mL로 확인되었다. HU033에 1.25~10 ㎍/mL 농도로 표준물질을 첨가하여 조제한 용액을 동일한 조건으로 반복 실험하여 시험한 결과, 전체 평균회수율은 100.26%로 분석의 높은 정확성을 확인하였다. HU033의 검체량을 달리하여 각각 5회 반복 분석한 결과 전체 RSD(%) 구간은 0.52~1.90%로 확인되었고, quisqualic acid 분석의 정밀성을 확인하고자 intra-day와 inter-day 정밀성을 확인하였다. Intra-day 정밀성은 0.24~0.41%, inter-day 정밀성은 0.02~0.66% 수준으로 확인되어 높은 정밀성을 나타내었다. 따라서 본 연구를 통해 HU033의 지표성분 quisqualic acid 분석법은 적합한 시험법임을 검증하였으며 향후 기능성 원료 개발을 위한 기초자료로 활용될 것으로 사료된다. In the current study, high performance liquid chromatography was used to validate and establish a method for identification of quisqualic acid (QA) in Quisqualis indica extract powder (HU033), which is widely used in health functional foods. Sample preparation was achieved by applying o-phthalaldehyde derivatization and protein hydrolysis. Analysis was performed on a C18 column with a gradient elution containing a mixture of sodium acetate (0.01 M, pH 4.6) and acetic acid (0.2 M) in water, and a flow rate of 1.0 mL/min methanol, detected at 338 ㎚. Method validation was achieved by measuring the specificity, linearity, accuracy and precision. Calibration curve of QA showed high linearity (R²=1), and limits of detection and quantification were determined to be 1.0 and 3.0 ㎍/mL, respectively. Recovery rate ranged from 98.66% to 101.11%, and QA content in HU033 was approximately 1.09%. Based on these results, we conclude that the developed method can be applied for quantifying QA in Quisqualis indica extract powder (HU033).
DS18B20 온도센서를 이용한 어항 자동 온도제어 장치
정혜림(Hye Lim Jung),오명환(Myeong Hwan Oh),김명관(Myung Gwan Kim) 한국IT마케팅학회 2014 한국IT마케팅학회 학술대회 Vol.2014 No.1
Nowadays IOT, smart phones, according to the development of IT technology, such as clouds, or the user is away distance, puppies equipped that it is not me summarized inevitably, tropical fish, a program for managing pets such as cats became easier it is to manage the pet been developed. To fit the reality is demand for ornamental fish pet is increasing, in this paper, using the IT technology, I think to try to make the automatic temperature control device of the fishing port that can be Fushisuru the water temperature of the fishing port.