전자기 듀오캐스팅으로 제조한 Al-Mn/Al-Si 하이브리드 알루미늄합금의 미세조직과 인장 특성

박성진,김종호,박준표,장시영,Park, Sung-Jin,Li, Tingju,Kim, Chong-Ho,Park, Jun-Pyo,Chang, Si-Young 한국재료학회 2012 한국재료학회지 Vol.22 No.2

The microstructure and tensile properties of Al-Mn/Al-Si hybrid aluminum alloys prepared by electromagnetic duocasting were investigated. Only the Al-Mn alloy showed the typical cast microstructure of columnar and equiaxed crystals. The primary dendrites and eutectic structure were clearly observed in the Al-Si alloy. There existed a macro-interface of Al-Mn/Al-Si alloys in the hybrid aluminum alloys. The macro-interface was well bonded, and the growth of primary dendrites in Al-Si alloy occurred from the macro-interface. The Al-Mn/Al-Si hybrid aluminum alloys with a well-bonded macro-interface showed excellent tensile strength and 0.2% proof stress, both of which are comparable to those values for binary Al-Mn alloy, indicating that the strength is preferentially dominated by the deformation of the Al-Mn alloy side. However, the degree of elongation was between that of binary Al-Mn and Al-Si alloys. The Al-Mn/Al-Si hybrid aluminum alloys were fractured on the Al-Mn alloy side. This was considered to have resulted from the limited deformation in the Al-Mn alloy side, which led to relatively low elongation compared to the binary Al-Mn alloy.

듀오캐스트 Al-Mg-Si/Al 하이브리드 합금의 미세조직과 기계적 변형 특성

한지민 ( Ji Min Han ),김종호 ( Chong Ho Kim ),박준표 ( Jun Pyo Park ),장시영 ( Si Young Chang ) 한국주조공학회 2012 한국주조공학회지 Vol.32 No.6

Al-Mg-Si/Al hybrid alloy was prepared by Duo-casting and the mechanical behavior was evaluated based on their microstructure and mechanical properties. The hybrid aluminum alloy included the Al-Mg-Si alloy with fine eutectic structure, pure Al with the grains in pure Al occurred from the macro-interface existing between Al-Mg-Si/ alloy and pure Al. The growth of columnar grains in pure Al occurred from the macro-interface. The tensile strength, 0.2% proof stress and bending strength of the hybrid aluminum alloy were almost similar to those of pure Al, and the elongation was much higher than the Al-Mg-Si alloy. The fracture of the hybrid alloy took place in pure Al side, indicating that the macro-interface was bonded and the mechanical behavior strongly depends on the limited deformation in pure Al side.

주면피폭선량 평가코드(INDAC)의 검증을 위한 월성원전 주면 삼중수소 농도 실측치와 예측치의 비교 평가

장시영,김창규,노병환,Jang, Si-Young,Kim, Chang-Kyu,Rho, Byung-Hwan 대한방사선방어학회 2000 방사선방어학회지 Vol.25 No.2

월성원전 주변에서 실측된 공기중 및 솔잎중 삼중수소 농도와 INDAC 코드 예측치의 비교 평가를 수행하였다. 또한, 방사성물질의 환경중 방출유형, 풍속분류, 지형 고려 유무 등에 따른 삼중수소 예측치의 변화를 측정치와 비교 평가함으로써, 규제실무에 적용할 수 있는 최적 기상자료 입력방안을 도출하였다 공기중 및 솔잎중 삼중수소 농도와 INDAC 코드 예측치의 비교평가 결과, 월성원전 주변 삼중수소 농도 예측치는 측정값의 불착실성, 지현의 복잡성, 해륙풍의 영향 등의 제한점에도 불구하고 규제검증에 필요한 정도의 보수성을 유지하면서도 삼중수소의 거동을 잘 모사함을 확인할 수 있었다. 또한, INDAC 코드에 적용된 솔잎중 삼중수소 농도의 평가방법론 즉, 대기내 수분중의 삼중수소 농도의 절반이 식물체내에 골고루 분포되어 있다고 가정하는 것은 규제 검증에 필요한 보수성을 확보하고 있음을 알 수 있었다. 최적 기상자료 입력방안의 도출을 위한 민감도 분석 결과, 혼합방출 및 지형을 고려하지 않는 경우에는 실측치 대비 과소 평가되는 부분이 있어 규제실무에 적용하기에는 적합하지 않은 것으로 나타났다. 따라서, 혼합방출을 고려하는 경우에는 58m 기상자료와 지형자료에 근거하여 대기확산인자를 평가하여야 하는 것으로 나타났다. The predicted results of INDAC code were compared with measured $^3H$ concentrations in air and pine-needle around the Wolsung site. The optimal sets of input data to INDAC were in addition selected by comparing the measured values with the predicted values of INDAC based on various conditions such as the release modes of effluents into the environment, the classification of wind classes, and the consideration of terrain. The predicted $^3H$ concentrations in air and pine-needle were shown to have good agreement with measured values, although there are some limitations such as uncertainties in measured values, complex topology around the site, and the land-sea breeze effects. The assumption on the $^3H$ behavior in vegetables or plants that the ratio of $^3H$ concentration in plant water to $^3H$ concentration in atmospheric water is 1/2 was shown to be conservative in terms of the audit calculation performed by the regulator. It was also found that data sets based on mixed mode and no terrain data were not appropriate for the audit calculation ensuring the compliance with regulations. Thus, if the mixed mode is considered as the release mode of effluents into the environment, meteorological data measured at 58 m height and terrain data should be used to evaluate the atmospheric dispersion factor.

EMS Al-Mg-Si/Al 하이브리드 합금의 계면에 미치는 열처리의 영향

이호훈(Ho Hun Lee),박성진(Sung-Jin Park),김종호(Jong-Ho Kim),박준표(Jun-Pyo Park),장시영(Si Young Chang) 한국소성가공학회 2013 한국소성가공학회 학술대회 논문집 Vol.2013 No.10

Al-Mg-Si/Al hybrid alloy was fabricated by Duo-casting, which is subject to the electromagnetic stirring(EMS), and the effect of heat treatment on interfacial characteristics was studied. After fabricating the hybrid alloy, some specimens were annealed at 100, 300 and 500℃ for 1h. And the other specimens were T6 treated (solution treatment at 500℃ for 1h, and aging at 160℃ for 5h). To investigate the effect of heat treatment, microstructure was observed by optical microscopy and scanning electron microscopy, and microhardness was measured. As annealing temperature increased, grain size of Al-Mg-Si alloy increased, and T6 heat treated Al-Mg-Si alloy showed a slight change in grain size. Near the macrointerface of hybrid alloy, microhardness increased gradually from pure Al side to Al-Mg-Si alloy side.

과학계량학적 정보분석을 통한 LED 및 광분야 유망기술 탐색에 관한 연구

장시영(Chang, Si-Young),이병철(Lee, Byoung-Chul),김윤배(Kim, Yun-Bae) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.3

본 연구는 과학계량학(scientometrics)을 활용하여 LED 및 광분야의 유망기술을 탐색하였다. 우선 Web of Science의 SCIE 논문 및 미국특허청(USTPO) 특허를 수집하여 키워드를 추출하였다. 추출된 키워드를 클렌징 과정을 통해 표준화하고, 동시단어 분석을 사용하여 LED 및 광분야의 논문과 특허 서지사항에 나타나는 정보간의 연합강도 (association strength)를 측정함으로써 기술의 패턴 및 경향을 밝혀내었다. 그리고 LED 및 광분야의 역동적인 변화를 추적하기 위하여 전략적 다이어그램을 도출하였다. 이를 통해 LED 및 광분야의 미래 유망연구영역 및 기술도출의 객관적인 방법으로서 과학계량학의 가능성을 보여준다. The aim of this research is to map the intellectual structure of the field of LED and optics during the period of 2000-2009. We utilize the scientometric tool of co-word analysis to reveal patterns and trends in the LED and optics field by measuring the association strengths of keywords (or IPCs). Data were collected from Science Citation Index Expanded (SCIE) and United Stated Patent and Trademark Office (USTPO) for the period of 2000-2009. Keywords were extracted from abstracts and further standardized using thesaurus. In order to trace the dynamic changes of the LED and optics field, the whole 10-year period was separated into two consecutive periods: 2000-2004 and 2005-2009. The results show that the LED and optics field has some established research themes and it also changes to embrace new themes.

초등학교 저학년 학생들의 스트레스를 감소시킬 수 있는 교실 환경 특징 - 서울특별시 ‘꿈을 담은 교실 만들기’ 사업을 중심으로 -

장시영(Chang, Si-Young),김석경(Kim, Suk-Kyung) 한국실내디자인학회 2022 한국실내디자인학회 학술대회논문집 Vol.24 No.1

한국인의 초과 방사선 암 위험도 평가에 근거한 국내원전의 안전목표치 설정 방법론

장시영,정운관,Chang, Si-Young,Chung, Woon-Kwan 대한방사선방어학회 1999 방사선방어학회지 Vol.24 No.3

통계청에서 최근에 발표한 한국인 인구통계 자료와 미국 학술원 산하 '방사선의 생물학적 영향 위원회'의 최근 보고서(BEIR-V)의 수정 상대위험 투사모델을 적용하여 한국인의 방사선 피폭에 의한 초과 암발생 위험도를 평가하였다. 인구통계 자료로부터 유도한 사소위험도(trivial risk) 및 계산된 방사선유발 초과 암 위험도를 비교한 후 사소위험도의 수준으로 개인의 피폭선량을 유지하기 위한 국내 원전의 안전운영 목표치를 유도하였다. 방사선 피폭 유발 초과 암 위험도는 0.1 Gy의 단일피폭의 경우에는 $5.5{\times}10^{-3}$, 1.0 mGy/y로 생애연속 피폭 시엔 $3.7{\times}10^{-3}$인 것으로 평가되었다. 한국인의 모든 원인에 의한 기저사망 위험도 및 사소위험도는 각각 $5.2{\times}10^{-3}$ 및 $5.2{\times}10^{-6}$인 것으로 예상되었다. 한국인의 사소위험도 및 방사선 위험도 평가 결과로부터 유도한 국내 원전운영의 안전목표치는 대략 0.05 mSv/y로, 이 값은 미국 원자력규제위원회(USNRC)가 연방규제법 10CFR50 부록 I에서 제시하고 있는 ALARA 지침값과 거의 동일한 값으로 밝혀졌다. By using the Korean demographic data and the modified relative risk projection model given in the Committee on the Biological Effect of Ionizing Radiation (BEIR) report-V under the U.S. National Academy of Science, the radiogenic excess risk in Korean population has been evaluated. On the basis of this risk, a safety goal for the safe operation of domestic nuclear power plants has been further derived in terms of personal dose. The baseline risk of death due to all causes in Korea and the trivial risk level, which the society considers safe, were estimated to be $5.2{\times}10^{-3}$ and $5.2{\times}10^{-6}$, respectively. The radiogenic excess cancer risk in Korea has been estimated to be $5.2{\times}10^{-3}$ for tie case of acute exposure to 0.1 Gy and $3.7{\times}10^{-3}$ for the case of chronic lifetime exposure to 1.0 mGy/y. On the basis of these risks estimate, the resulting safety goal for one year opeation of a reactor was 0.05 mSv, which is quite identical with the ALARA guideline prescribed by the USNRC in the Appendix I, 10CFR50.

플라즈마 전해 산화처리한 시효경화 Mg-Al 합금 피막의 기계적 및 전기화학적 특성

장시영,김예림,김양도,Chang, Si-Young,Kim, Ye-Lim,Kim, Yang-Do 한국재료학회 2007 한국재료학회지 Vol.17 No.12

Plasma electrolytic oxidation (PEO) treatment was performed on cast Mg-6 wt%Al alloy solution-treated at 693K for 16h and aged at 498K. The surface roughness, thickness, micro-hardness, wear and corrosion properties of coatings on solution-treated and aged Mg-6 wt%Al alloy were investigated. The coatings on aged Mg-6 wt%Al alloy had thinner layer and lower micro-hardness and wear resistance than the solution-treated Mg-6 wt%Al alloy. As the aging time increased, the thickness of coatings decreased while the surface roughness was almost no changed. In addition, the micro-hardness and wear property of coatings decreased with increasing the aging time unlike the uncoated Mg-6 wt%Al alloy showing the peak micro-hardness and the best wear property after aging for 16 h. However, the coatings on Mg-6 wt%Al alloy peak-aged for 16h revealed the best corrosion resistance in 3.5% NaCl solution, which was explained based on the microstructural characteristics.

A Control Room Dose Assessment for a 1300 MWe PWR Following a Loss of Coolant Accident

장시영,하정우,Chang, Si-Young,Ha, Chung-Woo Korean Association for Radiation Protection 1989 방사선방어학회지 Vol.14 No.1

프랑스의 1300 MWe 급(級) 표준(標準) P'4형 PWR 원전(原電)의 일차냉각재상실사고(一次冷却材喪失事故)(LOCA)시(時) 원전(原電) 주제어가내(主制御家內) 운전원(運轉員)에 대한 고사선(故射線) 피습선량(被濕線量)을 계산하여 주제어실(主制御室)의 체류안전성(滯留安全性)을 평가(評價)하였다. 본(本) 평가(評價)에서 사용(使用)된 제가정(諸假定)은 프랑스의 표준안전성분석보고서(漂準安全性分析報告書)에 따랐다. 본(本) 평가(評價)를 위하여 LOCA 사고시(事故時) 원자로건물외(原子爐建物外)로 방출(放出)되는 방사핵종(放射核種)의 방사능(放射能), 주제어실(主制御室)에서의 체적인자(體積因子) 및 제어실내(制御室內) 운전원(運轉員)의 전신(全身) 및 갑상선(甲狀膳) 피폭선량(被爆線量)을 사고발생후(事故發生後) 30일까지 전산(電算)할 수 있는 간단한 전산(電算)프로그램, COREX를 개발(開發)하였다. 본(本) 연구(硏究)에서 얻어진 계산결과(計算結果)는 대체적으로 프랑스의 EDF(불란서 전력주식회사(電力株式會社) 에서 제안(提案)한 결과(結果)와 대체적으로 잘 일치(一致)하였으나, 전신외부피폭선량(全身外部被爆線量)의 값은 일부(一部) 체적인자(體積因子) 값의 차이로 인(因)하여 일부 편차(偏差)를 보였다. The habitability of a reactor control room in a French 1300 MWe P'4 type PWR has been evaluated through the exposure dose assessment for the reactor operator following a Loss of Coolant Accident. The main hypotheses adopted in this evaluation are based on the French Standard Safety Analysis Report. A simple computer program, named COREX(Control Room EXposure), was developed to calculate : the time-integrated radioactivities released from the reactor building, the volume factors for radionuclides concerned and the resulting time-integrated external whole body and internal thyroid doses to the reactor operators staying in the control room up to 30 days following the LOCA. The results obtained in this study, on the whole, well agreed with those proposed by the EDF(Electricite de France) except for the case of the whole body exposure, which was attributed to the differences in the volume factors for the radionuclides concerned.

고교학점제 시행 고등학교의 홈베이스 공간 웰빙 디자인 요소 분석 - 웰빌딩 인증의 Mind와 Community 항목을 중심으로 -

장시영(Chang, Si-Young),김석경(Kim, Suk-Kyung) 한국실내디자인학회 2023 한국실내디자인학회 학술대회논문집 Vol.25 No.1