Corrosion Behavior of Hastelloy C-276 for Carbon-anode-based Oxide Reduction Applications

Jeon, Min Ku,Kim, Sung-Wook,Choi, Eun-Young Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.3

The corrosion behavior of Hastelloy C-276 was investigated to identify its applicability for carbon-anode-based oxide reduction (OR), in which Cl₂ and O₂ are simultaneously evolved at the anode. Under a 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar flow, the corrosion rate was less than 1 g·m^-2·h^-1 up to 500℃, whereas the rate increased exponentially from 500 to 700℃. The effects of the Cl₂-O₂ composition on the corrosion rate at flow rates of 30 mL·min^-1 Cl₂, 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂, and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ with a constant 170 mL·min^-1 Ar flow rate at 600℃ was analyzed. Based on the data from an 8 h reaction, the fastest corrosion rate was observed for the 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ case, followed by 30 mL·min^-1 Cl₂ and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂. The effects of the chlorine flow rate on the corrosion rate were negligible within the 5-30 mL·min^-1 range. A surface morphology analysis revealed the formation of vertical scratches in specimens that reacted under the Cl₂-O₂ mixed gas condition.

Corrosion Behavior of Inconel X-750 for Carbon Anode Oxide Reduction Application

Jeon, Min Ku,Kim, Sung-Wook,Lee, Sang-Kwon,Choi, Eun-Young Korean Radioactive Waste Society 2020 방사성폐기물학회지 Vol.18 No.3

The corrosion behavior of the Inconel X-750 alloy was investigated for its potential application under a Cl₂-O₂ mixed gas flow in an Ar atmosphere. The corrosion rate was found to be negligible at temperatures up to 400℃ under a flow rate of 30 mL·min^-1 Cl₂ + 170 mL·min^-1 Ar, whereas an exponential increase was observed in the corrosion rate at temperatures greater than 500℃. The suppression of the corrosion reaction due to the presence of O₂ was verified experimentally at flow rates of 30 mL·min^-1 Cl₂ (4.96 g·m^-2·h^-1), 20 mL·min^-1 Cl₂ + 10 mL·min^-1 O₂ (2.02 g·m^-2 ·h^-1), and 10 mL·min^-1 Cl₂ + 20 mL·min^-1 O₂ (1.34 g·m^-2·h^-1) under a constant Ar flow rate of 170 mL·min^-1 at 600℃ for 8 h. The surface morphology analysis results revealed that porous surfaces with tunnel-type holes were produced under the Cl₂-O₂ mixed-gas condition. Furthermore, the effects of the Cl₂ flow rate on the corrosion rate were investigated, indicating that its impact was negligible within the range of 5-30 mL·min^-1 Cl₂ at 600℃.

Variation of Harbor Oscillations in Yeongil Bay

Min­Su Jeon,Joong­Woo Lee,Jae­Hyun Jeong,Sang­Yong Yang,Young­Hwan Jeong 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-

  Today, harbor oscillation problems are the most significant factor to consider when designing harbors serving very large ships. In coastal harbors, large vessels moored in the elastic hawsers are often displaced due to the resonance between long period waves and mooring systems. As a result, cargo handling may be interrupted and the hawsers may be broken, especially when the amplification becomes extreme. The most significant harbor confronted with harbor oscillation problem in Korea is Pohang New port. Many cases of problems are being reported by the pilot association and the local office of MOMAF (Ministry of Maritime Affairs and Fisheries). However, it is difficult to prevent the arrival of long waves causing oscillation within this harbor. Moreover, the Korean government has already started a new port plan at the mouth of Yeongil Bay without addressing the problems that have occurred in Pohang New port. This study deals with the variation of harbor oscillation due to the construction of a 4.1 km breakwater at the bay mouth including the arrangement of the new berths. Numerical methods used are in fairly standard form from the extended mile slope equation. The obtained numerical results were compared with field measurement from the previous and this will bring a certain level of discussion and consideration of variation to the future port development.

Evaluation of High Power Light Emitting Diodes (HPLEDs) as Potential Attractants for Adult Spodoptera exigua (Hübner)

Min-Seok Oh,Sang-Guei Lee,Ju-Hyun Jeon,Hoi-Seon Lee 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.10

To response evaluation of high power light emitting diodes (HPLEDs) as potential attractants to the Spodoptera exigua adults, we investigated the attractiveness of specific wavelength, illuminance intensity and light-exposure time, and compared them to the fluorescent. The all light treatments with the 40 lux intensity attracted the significantly highest number of S. exigua. The optimal light-exposure time exhibited the highest attraction rate at the 60 min. When the attraction and repellent rate in the optimal conditions to the S. exigua was surveyed, the white HPLED exhibited the highest attraction rate (91.1%), whereas the red HPLED exhibited the most repellent rate (33.3%). When evatuated of illuminance efficiency with fluorescent as control, white and red HPLED were found to be 9.14 and 10.34 times more efficient than fluorescent. These data clearly show that both the 40 lux intensity and the 60 min light-exposure time by using the white HPLED was the most suitable for attraction of the S. exigua.

Surface Modification of Block Copolymer Through Sulfur Containing Plasma Treatment

Choi, Sang Wook,Shin, Jae Hee,Jeon, Min Hwan,Mun, Jeong Ho,Kim, Sang Ouk,Yeom, Geun Young,Kim, Kyong Nam American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.10

<P>Some of the important issues of block copolymer (BCP) as an application to the potential low cost next generation lithography are thermal stability and deformation during pattern transfer process in addition to defect density, line edge/width roughness, etc. In this study, sulfur containing plasma treatment was used to modify the BCP and the effects of the plasma on the properties of plasma treated BCP were investigated. The polystyrene hole pattern obtained from polystyrene polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) was initially degraded when the polystyrene hole was annealed at 190 degrees C for 15 min. However, when the hole pattern was treated using sulfur containing plasmas using H2S or SF6 up to 2 min, possibly due to the sulfurization of the polystyrene hole surface, no change in the hole pattern was observed after the annealing even though there is a slight change in hole shapes during the plasma treatment. The optimized plasma treated polystyrene pattern showed the superior characteristics as the mask layer by showing better thermal stability, higher chemical inertness, and higher etch selectivity during plasma etching.</P>

오죽잎차와 오죽죽순차의 성분 분석 및 항산화 효과

김상민 ( Sang Min Kim ),전제승 ( Je Seung Jeon ),강석우 ( Suk Woo Kang ),김우리 ( Woo Ri Kim ),이기덕 ( Ki Deok Lee ),엄병헌 ( Byung Hun Um ) 한국응용생명화학회 2012 Journal of Applied Biological Chemistry (J. Appl. Vol.55 No.2

Nutritional components of Ojuk leaf tea and Ojuk shoot tea prepared from the leaves and shoots of black bamboo (Phyllostachys nigra Munro) by tea manufacturing process were evaluated. In addition, the extraction yield of water soluble components from these teas in the general tea brewing condition (water extraction in 80oC for 10 min.) and the contents of polyphenol and flavonoid were compared with not only the dried raw materials, but also green tea and mate tea. Finally, offline and online scavenging activities against 2,2`-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid) (ABTS) and di(phenyl)-(2,4,6 trinitrophenyl)iminoazanium free radicals were investigated to evaluate the antioxidant activity and explore the components showing ABTS free radical scavenging activity from tea infusion. These results demonstrated that these teas from black bamboo contain various nutritional components and can be used as traditional tea beneficial to human health.

The Korean Association of lnternal Medicine : Poster Session ; PS 1357 : Nephrology ; Age is the Strongest Effector for the Relationship between Estimated Glomerular filtration Rate and Coronary Artery Calcifi cation in Apparently Healthy Korean Adults

( Hyun Beom Chae ),( Eun Jung Rhee ),( Hae Jung Park ),( Min Kyung Lee ),( Won Seon Jeon ),( Se Eun Park ),( Cheol Young Park ),( Won Young Lee ),( Ki Won Oh ),( Sung Woo Park ) 대한내과학회 2014 대한내과학회 추계학술발표논문집 Vol.2014 No.1

Background: Cardiovascular disease (CVD) is a major clinical problem and the most common cause of morbidity and mortality in patients with chronic kidney disease (CKD). Coronary artery calcifi cation (CAC) is a potential mechanism that explains the association between renal function and cardiovascular mortality. We aimed to evaluate the association between renal function and CAC in apparently healthy Korean subjects. Methods: In 23,617 participants in the health screening program in Kangbuk Samsung Hospital health screening program from January 2010 to December 2011, estimated glomerular fi ltration rate (eGFR) was assessed by Cockcroft-Gault equation. Coronary artery calcium score (CACS) was measured by multi-detector computed tomography (MDCT). Subjects were divided into 3 groups according to the CKD Staging system with eGFR grade; stage 1: eGFR = 90 mL/min/1.73 m2, stage 2: eGFR 60-89 mL/ min/1.73 m2, stage 3: eGFR 30-59 mL/min/1.73 m2. Results: Mean age of the participants was 41.4 years, and mean eGFR was 103.6±21.7 mL/min/1.73 m2. Hypertension and diabetes were noted in 43.7% and 5.5% of the participants, respectively. eGFR showed weakly negative but signifi cant association with CACS in bivariate correlation analysis (r=-0.076, p<0.01). Mean CACS signifi cantly increased from CKD stage 1 to 3. The proportion of subjects who had CAC signifi cantly increased from CKD stage 1 to 3. Although odds ratio for CAC signifi cantly increased from stage 1 to 3 after adjustment for confounding factors, this signifi cance was inversed when age was included in the model. Age was the strongest factor that affects CAC. Conclusions: This study performed in young Korean subjects with relatively normal renal function, age was the mostly strongest effector on the association between eGFR and the degree of CAC.

알루미늄 PEO 코팅의 결정상에 미치는 공정 조건에 대한 연구 I. Unipolar 펄스와 코팅시간

김배연,함재호,이득용,김용남,전민석,김기윤,최지원,김성엽,김광엽,Kim, Bae-Yeon,Ham, Jae-Ho,Lee, Deuk Yong,Kim, Yong-Nam,Jeon, Min-Seok,Kim, Kiyoon,Choi, Ji-Won,Kim, Sung Youp,Kim, Kwang Youp 한국결정성장학회 2014 韓國結晶成長學會誌 Vol.24 No.2

전해질로 $Na_2SiO_3$을 사용하여 A1050 알루미늄 판재를 pulse 폭 $ 2000{\mu}sec$, impulse 420 V, 400 ${\mu}$sec의 unipolar pulse로 플라즈마 전해 산화 코팅(plasma electrolytic oxidation coating)을 하여 산화 피막을 2, 5, 15, 30분에 따라 형성시킨 다음 산화피막을 분석하였다. 표면에 형성된 산화물의 결정상은 ${\alpha}-alumina$와 ${\gamma}-Alumina$로서 시간에 따른 변화는 없었다. 반응 초반에는 ${\gamma}-Alumina$가 많이 생성되었지만 시간이 갈수록 ${\gamma}-Alumina$의 양에는 변화 없이 ${\alpha}-alumina$가 많이 생겨남을 알 수 있었다. 이런 결과는 micro plasma에 의해서 ${\gamma}-Alumina$가 우선 생성되고, 이후 계속되는 micro plasma의 열에 의해서 ${\alpha}-alumina$로의 전이가 일어나기 때문으로 판단된다. Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1050, were investigated. The electrolyte of PEO was $Na_2Si_2O_3$ and KOH. Unipolar pulse, $ 2000{\mu}sec$ with $400{\mu}sec+420V$ impulse, were applied for 2 min, 5 min, 15 min, and 30 min. ${\gamma}-Alumina$, as well as ${\alpha}-alumina$, was main crystal phase. ${\gamma}-Alumina$ was appeared in the beginning, then the amount of ${\alpha}-alumina$ was increased with time, but the amount of ${\gamma}-Alumina$ remained constant without any increasing. So, it is concluded that plasma gas produce ${\gamma}-Alumina$ at the first, and then ${\gamma}-Alumina$ transform ${\alpha}-alumina$ finally. During the transformation, high temperature of micro plasma gives transformation energy.

수근관 증후군의 국소 스테로이드 주사

조민규,이성훈,강은영,전평식,최영태 大韓再活醫學會 2000 Annals of Rehabilitation Medicine Vol.24 No.5

보호경찰관들의 탈북자 지원 경험 분석

전우택,윤덕용,민성길 大韓神經精神醫學會 2001 신경정신의학 Vol.40 No.2

본 연구는 남한에 들어와 살고 있는 탈북자들의 남한 사회 적응 지원 및 신변보호를 2년간 담당한 경찰관들을 대상으로 그들의 활동 속에서 경험한 지원상의 어려움, 인간 관계, 관계 개선을 위한 노력 등을 분석함으로써 향후 탈북자 지원 업무를 담당할 경찰관들과 자원봉사자들, 관련 공무원들을 활동을 더욱 효과적으로 하는데 목적이 있다. 방법: 과거 탈북자 보호 업무를 2년간 담당하였던 전국의 경찰관 전원을 대상으로 경찰청의 도움을 받아 설문조사를 실시하였다. 결과: 총 172명의 경찰관이 설문에 답하였다. 탈북자들의 성별, 연령, 학력에 따른 인간관계 평균점수에는 통계적으로 유의한 차이가 없었다. 그러나 인민학교 출신 탈북자들은 유일하게 시간이 지남에 따라 인간 관계가 더 나빠지는 것으로 나왔다. 또한 인간관계 유형도 연령대에 따라 다르게 나왔다. 탈북 경로에 있어 북한에서 직접 남한으로 들어온 사람들이 러시아, 중국 등을 경유하여 들어온 사람들보다 인간관계 평균점수가 통계적으로 유의하게 더 좋게 나왔다. 경찰관들의 연령대에 따른 인간관계 평균점수의 차이는 없었으나 관계 유형에는 차이가 있었다. 경찰관들이 탈북자들의 문제를 직접 해결을 하려고 나섰을 경우보다 교육행동적인 태도를 가지고 있었을 때 인간관계 평균점수가 통계적으로 더 유의하게 좋게 나왔다. 적응 초기에는 불안과 불신, 사회 부적응 등이 인간 관계에 문제가 되었으나 후기에는 자립의지 부족, 이기주의, 돌출행동 등이 문제가 되었다. 결론: 본 연구는 보호경찰관들과 탈북자들간의 인간관계가 그들의 인구학적 특징, 탈출 경로 등에 따라 다르게 나타남을 보여주었다. 또한 인간 관계를 좋게 하기 위한 노력의 방법이나 지원 방법에 따라 인간관계가 다르게 나타남을 보였다. 이것은 탈북자들을 지원함에 있어 과학적인 지침이 요구됨을 보여주는 것이었다. Objectives: The purpose of this study is to analyze the experience of South Korean police-men who are in charge of supporting the North Korean defectors' adaption to South Korean society for 2 years. Method: Written-form survey questionnaire were sent to all policemen who were in charge of defectors with the help of the National police bureau. Results: 172 policemen answered to survey questionnaire. There was no difference of human relationship score according to the defectors' sex, age, academic career. But defectors with low academic career showed bad human relationship as time went by. The type of human relationship change were different according to the defectors' age. Defectors who entered to South Korea directly from North Korea in short period had a better relationship in comparison with those who escaped to China or other third countries and stayed there for a long time to get a chance to enter to South Korea. As the policemen are younger, the relationship scores were better. But when some problem occurred in their relationship, younger policemen were less successful in solving the problem. There were many kind of efforts of policemen to improve the human relationship and it showed that the education-oriented effort is more effective and successful than direct problem-solving effort. Conclusions: This study showed that the human relationship of defectors and policemen in charge are affected by some demographic factors and defection routes and the types of efforts of policemen to improve the human relationship. It was suggested that the role of policemen in charge of defectors should be more well-defined, and NGO(Non Government Organization) need to have more continuos and specified program to help defectors' adaptation. Finally, the importance of continuing scientific researches about defectors' adaptation was emphasized.