굴, 김 및 조피볼락에서 다환성방향족탄화수소(polycyclic aromatic hydrocarbons, PAHs)의 잔류에 미치는 요인에 대한 연구

김강전,최상훈,박관하 한국패류학회 2008 The Korean Journal of Malacology Vol.24 No.3

A total of 15 different residues of polycyclic aromatic hydrocarbons (PAHs) were analyzed in 20 samples each of Pacific oysters, dried laver and rockfish obtained from seafood markets. The prevalence of samples in which more than one PAH residues were found ranked as oyster (75%) > rock fish hepatopancreas (35%) > rockfish muscle = laver (0%). To estimate factors contributing to this residue level difference among organisms, at first the three organisms were exposed to phenanthrene, a representative PAH, in the laboratory experiments at 0.01 or 0.1 μg/ml for 2 weeks and tissue concentrations were analyzed. Phenanthrene levels after exposure were higher in the oyster digestive gland, laver and rockfish hepatopancreas, and in contrast they were lower in the oyster whole meat or rockfish muscle. This finding disproves any close relationship between the residue difference observed in market samples and concentrating properties of PAHs. The second possible factor analyzed was total lipid contents in the three organisms. The higher lipid levels in rockfish hepatopancreas may partially explain higher PAH residues in this organ compared to its muscle, however, such lipid factor does not seem to be important in other organism samples. The third factor estimated was the assessment of cytochrome P450 enzyme activity by measuring 7-ethyoxyresorufin-O-deethylase (EROD) activity. Higher EROD activity in rockfish is likely to contribute to lower PAH residue levels in market rockfish samples, in particular when compared to oyster samples. Factors other than examined in this study, e.g., different exposure history, organisms' ability to escape, ingestion through prey organisms, and post-harvest loss should be the research in the future studies. In summary, significance lies in the fact that the authors attempted for the first time to assess factors contributing to residence of PAHs in three major seafoods consumed by Koreans.

김 및 굴에서의 polycyclic aromatic hydrocarbons ( PAHs ) 의 농축현상 및 유통시료에서의 잔류량 연구

김정상,황인영,박관하,김강전 한국식품과학회 1999 한국식품과학회 학술대회 Vol.1999 No.1

냉간금형 인서트(insert)용 주강의 미세조직

강전연,박준영,김호영,김병환,Kang, Jun-Yun,Park, Jun-Young,Kim, Hoyoung,Kim, Byunghwan 한국열처리공학회 2017 熱處理工學會誌 Vol.30 No.5

The microstructure of a high-carbon and high-chromium cast steel (HK700) for cold-work die inserts was analyzed by advanced scanning electron microscopy. A continuous network of primary $M_7C_3$ carbide was developed among austenitic matrix after casting. A small amount of $M_2C$ was added to the carbide network owing to the enrichment of Mo and W during the solidification. After quenching in which the austenitization was performed at $1030^{\circ}C$ and double tempering at $520^{\circ}C$, the network structure of $M_7C_3$ was preserved while most of the matrix was transformed to martensite because of additional carbide precipitation. The $M_2C$ in the as-cast microstructure was also transformed to $M_6C$ due to its instability. The continuous network of coarse carbides owing to the absence of hot-working had little influence on the hardness after quenching and tempering, whereas it resulted in severe brittleness upon flexural loading.

Prestrain이 유황 쾌삭강의 절삭 특성과 기계적 물성에 미치는 영향

김종범,안형호,배재민,손동민,오규환,강전연,한흥남 한국소성·가공학회 2023 한국소성가공학회 학술대회 논문집 Vol.2023 No.5

냉간프레스금형용 고성능 주강 개발

강전연 ( Jun-yun Kang ),김병환 ( Byunghwan Kim ),김호영 ( Hoyoung Kim ) 한국열처리공학회 2018 熱處理工學會誌 Vol.31 No.6

The microstructure of a newly developed alloy tool steel (KV1) for casting cold-work press dies was analyzed using advanced scanning electron microscopy. Its mechanical properties and durability in use as piercing inserts were tested. It contained a continuous network structure which originated from the micro-segregation during solidification and was composed of retained austenite and primary carbides. However, after quenching and tempering, its continuity was destroyed due to the decomposition of austenite. The discontinuous spatial distribution and the smaller amount of primary carbide in the network presented KV1 enhanced ductility compared to the common alloy (HK700). The reduced C and Cr, the addition of V resulted in a small amount of primary carbides which primarily consisted of MC, as well as fine and uniform dispersion of precipitates. Owing to these features, KV1 exhibited delayed initiation of chipping when used for piercing inserts. (Received September 28, 2018; Revised October 10, 2018; Accepted October 15, 2018)

UMOS (Updateable Model Output Statistics) 시스템 개발

강전호,홍기옥,서명석,김찬수,서영경,최준태,이미선 한국기상학회 2008 한국기상학회 학술대회 논문집 Vol.2008 No.-

본 연구에서는 기상청 수치예보 자료를 이용하여 통계예측모델(MOS)을 개발하고, 이를 기반으로 모델의 변화 및 교체시 연속적으로 통계예측이 가능한 UMOS를 설계/개발하였다. Fig. 2는 2007년 가을(8월~12월) 150일 동안 남한 76개 관측 지점에 대해 새로운 모델의 샘플링 수에 따른 UMOS의 예측 수준을 나타낸 것이다. 기존의 모델과 새로운 모델의 차이로 인해 UMOS 초반에는 상관계수가 매우 낮고 편의도 크게 나타나지만, 새로운 모델의 샘플링 수가 100일이 넘어가면서 상관계수는 085~0.9 이상, 편의는 0에 가깝게 산출되는 것을 알 수 있다. Fig. 3은 RDAPS, KWRF, RDAPS 자료를 기반으로 개발한 MOS에 RDAPS (MOS_R)와 KWRF (MOS_K)를 각각 적용한 결과, 그리고 UMOS의 편의를 나타낸 것이다. RDAPS의 모의수준은 평균적으로 상관계수, 편의, RMSE가 각각 0.89, 0.33, 3.74, KWRF는 0.89, -0.061, 3.36으로 나타났다. MOS_R과 MOS_K의 모의수준은 상관계수, 편의, RMSE가 각각 0.96, 0.39, 2.14 및 0.92, -0.19, 2.91로 나타났다. UMOS의 검증수준은 Fig. 2보면 알 수 있듯이, 초반에는 검증수준이 좋지 않지만, 약 100일 이후에는 상관계수, 편의, RMSE가 각각 0.88, -0.23, 3.35 정도로 안정되게 산출하고 있다. 그리고 UMOS의 편의 분포는 통계모델을 거치지 않은 RDAPS나 KWRF의 모의수준에 비해 비교적 안정적으로 산출하고 있음을 알 수 있다. 〈이미지 참조〉 예보 모델 개발 및 시스템 구축-MOS 시스템의 기능 확대: UMOS 시스템 개발-"의 일환으로 수행된 것입니다.

냉간금형용 합금공구강 분말 및 적층조형체의 미세조직

강전연,윤재철,김호영,김병환,최중호,양상선,유지훈,김용진,Kang, Jun-Yun,Yun, Jaecheol,Kim, Hoyoung,Kim, Byunghwan,Choe, Jungho,Yang, Sangsun,Yu, Ji-Hun,Kim, Yong-Jin 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.3

A cold-work tool steel powder is used to fabricate 3-dimensional objects by selective laser melting using a high-pressure gas atomization process. The spherical powder particles form continuous carbide networks among the austenite matrix and its decomposition products. The carbides comprise Nb-rich MC and Mo-rich $M_2C$. In the SLM process, the process parameters such as the laser power (90 W), layer thickness ($25{\mu}m$), and hatch spacing ($80{\mu}m$) are kept fixed, while the scan speed is changed from 50 mm/s to 4000 mm/s. At a low scan speed of 50 mm/s, spherical cavities develop due to over melting, while they are substantially reduced on increasing the speed to 2000 mm/s. The carbide network spacing decreases with increasing speed. At an excessively high speed of 4000 mm/s, long and irregularly shaped cavities are developed due to incomplete melting. The influence of the scan pattern is examined, for which $1{\times}1 mm^2$ blocks constituting a processing layer are irradiated in a random sequence. This island-type pattern exhibits the same effect as that of a low scan speed. Post processing of an object using hot isostatic pressing leads to a great reduction in the porosity but causes coarsening of the microstructure.

Development of Updateable Model Output Statistics (UMOS) System for Air Temperature over South Korea

강전호,서명석,홍기옥,김찬수 한국기상학회 2011 Asia-Pacific Journal of Atmospheric Sciences Vol.47 No.2

In this study, a Updateable Model Output Statistics (UMOS)system has been developed for the forecast of 3-h temperature over South Korea using two significantly different models’ (Regional Data Assimilation and Prediction System (RDAPS) and Korea Meteorological Administration (KMA) Weather Research and Forecasting (WRF) model (KWRF)) outputs based on the Canadian UMOS system (Wilson and Vallee, 2002; 2003). The UMOS system is designed to consider the local climatology and the model's forecasting skills. The 20most frequently selected potential predictors for each season, station,and forecast projection time from the 67 potential predictors of the Model Output Statistics (MOS) system, were used as potential predictors of the UMOS system. The UMOS equations are developed by a weighted blending of the new and old model data, with weights chosen to emphasize the new model data while including enough old model data in the development to ensure stable equations and a smooth transition to dependency on the new model. The UMOS equations were updated regularly at a predefined time interval to consider the changes of covariance structure between the new model output and observations as the new model data increase. The validation results showed that seasonal mean bias, Root Mean Square Error (RMSE),and correlation coefficients for the total forecast projection times are −0.379~0.055oC, 1.951~2.078oC, and 0.741~0.965, respectively. Although,the forecasting skills of UMOS system are very consistent without regard to the season and geographic location, the performance is slightly better in autumn and winter than in spring and summer, and better in coastal regions than in inland region. When we take into account the significant differences of the RDAPS and KWRF, the UMOS system can be used as a supplementary forecasting tool of the MOS system for 3-h temperature over South Korea. However, the UMOS system is very sensitive to the selected number and/or types of predictors. Therefore, more work is needed to enable the use of the UMOS system in operation, including tuning of the number and types of potential predictors and automation of the updating processes of the UMOS equations.

Deep SVDD 알고리즘 기반의 품질 검사 시스템 설계

김정준,지성철,김승우,전광우,강전성,정현준 한국컴퓨터정보학회 2023 韓國컴퓨터情報學會論文誌 Vol.28 No.11

In manufacturing companies that focus on small-scale production of multiple product varieties, defective products are manually selected by workers rather than relying on automated inspection. Consequently, there is a higher risk of incorrect sorting due to variations in selection criteria based on the workers' experience and expertise, without consistent standards. Moreover, for non-standardized flexible objects with varying sizes and shapes, there can be even greater deviations in the selection criteria. To address these issues, this paper designs a quality inspection system using artificial intelligence-based unsupervised learning methods and conducts research by experimenting with accuracy using a dataset obtained from real manufacturing environments.

참굴에서의 Polycyclic Aromatic Hydrocarbons의 축정성과 생화학적 변화I: Fluoranthene을 model 물질로 한 연구

서영호,정의영,김강전,임완수,김희연,류동기,최선남,황인영,김정상 한국패류학회 1998 The Korean Journal of Malacology Vol.14 No.2

참굴에 다환성방향족탄화수소(PAHs)의 축적성과 이 물질들이 미치는 독성을 평가하기 위해 해양환경에서 빈번히 검출되는 PAHs 중의 하나인 fluoranthene을 사용한 모델연구를 수행하였다. Fluoranthene을 0.01-1ppm의 농도로 2주간 참굴에 노출시켰을 때 참굴 조직내의 fluoranthene의 농도는 노출기간 및 노출농도에 비례하여 최고 40-70배까지 증가하였다. 소화맹낭과 폐각근의 지질 과산화물가는 노출기간 및 노출농도에 관련하여 현저히 증가하였으며 수용성단백질의 함량은 노출기간이 길어짐에 따라 서서히 감소하였다. 그러나 glycogen 함량, nucleoside/nucleotide, DNA 및 RNA 함량은 변화하지 않았다. 이 결과로 fluoranthene은 굴의 조직내로 원활하게 축적함을 확인하였다. 또한 과산화지질의 함량은 fluoranthene에의 오염에 대해 신속히 반응하는 지표의 하나로 추정되며 수용성단백질의 감소도 비록 시간적으로 다소 둔감하기는 하나 또 다른 지표가 될 수 있을 것으로 사료된다.