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℃.

자궁내 태아사망의 임상적 고찰

이권해,이정재,조현철,이석민,이임순,이해혁,김권대,이순곤,남계현 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.2

Objective: This study was designed to evaluate diagnosis and complication, prognosis during clinical study of cases of intrauterine fetal death. Methods and materials: This is a clinical study of 56 cases of the intrauterine fetal death among 8064 deliveries at Seoul Sunchunhyang university hospital during 5 years from January, 1994 to December, 1998. Results: The incidence was 0.7%. The age distribution of mothers was 18 - 44 years and was highest in the 25 - 29 years range(46.4%). The parity was the most highest in the nulliparous group(51.8%). The most common gestational weeks was 20 - 28 weeks gestational period(46.4%), and most common presentation was cephalic(73.5%). The most common weights of the intrauterine fetal death was from 5,00gm to 1,000g(48.2%). The mode of the most common delivery was the induction of delivery(57.2%). The etiologic factors were: unknown(42.9%), preeclampsia(17.9%), chorioamnionitis(14.3%), congenital anomaly(12.5%), abruptio placenta(7.1%), cord complication(3.6%), placenta previa, death of one for twin. There were 2 cases of maternal complication(DIC, Uterine atony). Conclusion : Intrauterine fetal death should be diagnosised early and treated properly to reduce risk of the maternal complication.

A Quantitative A naly sis of the Fire Hazard Generated from Hydrogen Fuel Cell Electric Vehicles

Sungwook Kang(Sungwook Kang),Kyu Min Lee(Kyu Min Lee),Minjae Kwon(Minjae Kwon),Ohk Kun Lim(Ohk Kun Lim),Joung Yoon Choi(Joung Yoon Choi) 한국화재소방학회 2022 International Journal of Fire Science and Engineer Vol.36 No.2

There is a lack of information on (i) the potential fire load of new green-technology vehicles, (ii) flame spread behavior, (iii) thermal impacts on high-pressure hydrogen storage vessels (HSVs) and lithium-ion batteries (LIBs) during fuel cell electric vehicles fires (FCEVs), and (iv) thermal damage to adjacent vehicles and upper structural members during FCEV fires occurring in civil structures, such as underground spaces, multi-story parks, and tunnels. In view of this, a full-scale fire test was conducted in this study to quantitatively assess the fire risk of hydrogen FCEVs. Large-scale cone calorimetry was used to quantify the thermal intensity released from the FCEV fire. The flame spreading behavior through an FCEV with HSVs and LIBs was observed using the thermocouples installed. Changes in the temperature and irradiance around the FCEV fire were also measured using an instrumented test rig. The peak heat release rate, total heat released, and fire growth rate were observed to be 5.99 MW, 11.8 GJ, and 0.0055 kW/s², respectively. The temporal point of hydrogen gas release from the HSVs' thermal pressure relief device (TPRD) was estimated to be 16.2-26.2 min. The initiation of thermal runaway of LIBs was deduced from the temperature-time profiles of the LIB modules and their metal housing approximately 22.2 min after HCEV ignition. Moreover, FCEV fires could thermally impair adjacent upper structural members by 800 ℃ combustion gas for at least 13 min and emit a median heat flux of 27.2 kW/m² (peak heat flux of 76.5 kW/m²) to adjacent vehicles. The measurements and findings obtained from this study can contribute to the evaluation of and further studies on newly emerging fire hazards.

Effects of hydrogen plasma treatment on SnO2:F substrates for amorphous Si thin film solar cells

Min-Seung Choi,Young-Ju Lee,Jung-Dae Kwon,Yongsoo Jeong,Ju-Yun Park,강용철,Pung Keun Song,Dong-Ho Kim 한국물리학회 2013 Current Applied Physics Vol.13 No.8

We investigated the effects of hydrogen plasma treatment on the physical and electrical properties of fluorine-doped tin oxide (FTO) films used for amorphous silicon (a-Si) thin film solar cells. A slight increase in carrier concentration by the hydrogen doping effect was observed for the FTO film exposed to the hydrogen plasma for 5 min. For further exposure to the plasma, the chemical reduction became prominent and resulted in deterioration of the electrical and optical properties of the film. XPS analysis revealed that the chemical reduction of SnO2 to Sn metallic state occurs on the surface region. It was found that the defects formed by hydrogen plasma act as recombination centers at the interface between FTO electrode and p-layer of a-Si solar cells. This phenomenon resulted in the deterioration of the cell performance. The averaged conversion efficiency (6.82%) of the cells on pristine FTO hydrogen substrate was decreased to 5.81% for the cells on FTO treated for 5 min, which is mainly attributed to the decrease in short-circuit current density.

폐경기 여성에서 호르몬 대치 요법시 병행 투여된 프로제스토젠 투여 방법에 따른 혈청 지질 및 지단백에 미치는 영향

이임순,전섭,이순곤,이해혁,이권해,정집광,이석민 순천향의학연구소 1998 Journal of Soonchunhyang Medical Science Vol.4 No.1

Objective : The purpose of our study is to evaluate the effect of different administration method of progestogen on lipid profiles including total cholesterol, LDL(low density lipoprotein)-cholesterol, HDL(high density lipoprotein)-cholesterol, triglycerides during hormone replacement therapy in postmenopausal women. Methods and Materials : Seventy-one postmenopausal women who were assigned to following groups (Group I : conjugated equine estrogen(CEE), 0.625 mg/day plus continuous medroxyprogesterone acetate (MPA), 2.5mg/day, Group II : CEE, 0.625 mg/day plus cyclic MPA, 5mg/day for 12days/month. And we measured serum total cholesterol, high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, and triglycerides before hormone replacement therapy(HRT) and 12 months later after hormone replacement therapy. Results: 1. Total cholesterol decreased in group I,III. 2. HDL-cholesterol increased in group I,II,III. 3. LDL-cholesterol decrease in group I,II. 4. Triglycerides increased in group I,II,III. There was significance in serum total cholesterol and LDL-cholestrerol among three groups. Conclusions : Estrogen alone or in combination with progestogen both in cyclic and continuous use improves lipid profiles, so medroxyprogesterone acetate(MPA) does not seem to blunt estrogenic effect on lipid profiles.

크론병에 대한 CoPPLX의 방어효과에 대한 연구

이호학,김유림,문창기,이재일,양병윤,김종수,이정민,정재혁,안석진,박상준,김윤권,김소연,김영중,조민구,최영자,장성조 圓光大學校 醫科學硏究所 2005 圓光醫科學 Vol.20 No.1

다산부에서 자간전증의 임상적 고찰

이주롱,이석민,한효상,이해혁,이임순,이권해 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.2

목적 : 전자간증 산모에서 초임신부와 다산부 각각의 임상적 특징을 조사하여 비교 분석하고자 하였다. 연구방법 : 1998년 1월부터 1999년 12월까지 2년간 순천향대학 서울병원에서 입원 분만한 임신성 고혈압성 질환 환자중 초임신부 106명과 다산부 50명, 총 150명을 대상으로 임상통계학적으로 조사 분석하였다. 결과 : 분만까지 임신기간의 비교시 초임신부에서는 33-36주에서 17.9%였고 다산부에서는 34.0%로, 다산부에서 조기분만의 예가 의의있게 많았다. 신생아 체중이 2500g 미만인 군이 초임신부군에서는 36.8%였고 다산부군에서는 62.0%로 다산부군에서 더 많았다. 임신성 고혈압성 질환의 중등도를 보면 중증자간전증의 초임신부에서 35.8%와 다산부에서는 44.0%로, 초임신부에 비해 다산부군의 중증 자간전증의 비율이 많았다. 결론 : 중증 임신성 고혈압성 질환이 다산부군에서 더 많았으며 적은 주수에서 제왕절개술을 시행해 출생아의 체중이 초임신부군에 비해 더 작았고 Apgar 점수도 더 낮았다. Objective : To study the clinical differences of primiparous and multiparous preeclamptic patients. Methods : We statistically analyzed 106 primiparous and 50 multiparous preeclamptic patients who were admitted to the Soonchunhyang University Hospital from January 1998 to December 1999. Results : It was statistically found that multiparae were more likely to give premature birth than primiparae: Thirty four percents of multiparae gave birth in the period between the 33rd and the 36th gestational weeks while 17.9% of primiparae did in the same period. Sixty two percents of the newborn babies of multiparae weighed less than 2500g. Among primiparae, the ratio was 36.8%. In addition, more multiparae(44.0% vs. 35.8%) suffered from severe preeclampsia. Conclusion : severe preeclampsia was found more frequently among multiparae. Since they gave birth earlier by cesarian section than primiparae, their babies weighed less and had lower apgar scores.

Label-free, microfluidic separation and enrichment of human breast cancer cells by adhesion difference

Kwon, Keon Woo,Choi, Sung Sik,Lee, Sang Ho,Kim, Byungkyu,Lee, Se Na,Park, Min Cheol,Kim, Pilnam,Hwang, Se Yon,Suh, Kahp Y. GENERAL AND APPLIED CHEMISTRY JOURNALS 2007 LAB ON A CHIP Vol.7 No.11

<P>A label-free microfluidic method for separation and enrichment of human breast cancer cells is presented using cell adhesion as a physical marker. To maximize the adhesion difference between normal epithelial and cancer cells, flat or nanostructured polymer surfaces (400 nm pillars, 400 nm perpendicular, or 400 nm parallel lines) were constructed on the bottom of polydimethylsiloxane (PDMS) microfluidic channels in a parallel fashion using a UV-assisted capillary moulding technique. The adhesion of human breast epithelial cells (MCF10A) and cancer cells (MCF7) on each channel was independently measured based on detachment assays where the adherent cells were counted with increasing flow rate after a pre-culture for a period of time (<I>e.g.</I>, one, two, and four hours). It was found that MCF10A cells showed higher adhesion than MCF7 cells regardless of culture time and surface nanotopography at all flow rates, resulting in label-free separation and enrichment of cancer cells. For the cell types used in our study, an optimum separation was found for 2 hours pre-culture on the 400 nm perpendicular line pattern followed by flow-induced detachment at a flow rate of 200 µl min<SUP>−1</SUP>. The fraction of MCF7 cells was increased from 0.36 ± 0.04 to 0.83 ± 0.04 under these optimized conditions.</P> <P>Graphic Abstract</P><P>A label-free microfluidic cell separation and enrichment device is presented here by using cell adhesion as a physical marker. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b710054j'> </P>

레이저 웨이퍼 다이싱 장비의 가공 특성 평가

한민섭,김성수,민병권,이승우,이진하,이혜진 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

As the semiconductor wafer is required to be thinner for better compactness and higher integrity of the electronic products, mechanical dicing saw technique using the diamond blade is facing serious problems such as low cutting speed, tool wear, side wall crack and back side chipping. Recently, UV laser dicing process has emerged as an alternative methods to the blade dicing especially for the very thin wafers below 100㎛. In this study 355 nm UV laser dicing system has been developed in order to improve the productivity and reliability of ultra thin wafer dicing process. For the quality improvement of the developed dicing system various laser parameters are investigated such as power, speed and frequency of the laser beam. Moreover various measurement techniques are employed to evaluate the dicing quality using optical microscope, SEM and focused ion beam.

기계적 자극을 이용한 인체 중간엽줄기세포로부터 유사-섬유모세포로의 분화 유도

최경민 ( Kyung Min Choi ),서영권 ( Young Kwon Seo ),윤희훈 ( Hee Hoon Yoon ),권순용 ( Soon Yong Kwon ),이화성 ( Hwa Sung Lee ),박용순 ( Yong Soon Park ),손영숙 ( Young Sook Son ),송계용 ( Kye Yong Song ),김영진 ( Young Jin Kim 한국조직공학과 재생의학회 2006 조직공학과 재생의학 Vol.3 No.4

Recently, in vitro reconstruction of anterior cruciate ligament(ACL) has been tried using tissue engineering technique, especially mesenchymal stem cell(MSC) is considered as a good cell source. In this study, we tried to find the effect of mechanical stimulus on the differentiation of bone marrow-derived MSC into ACL fibroblastlike cell using a cell training bioreactor imposing cyclic mechanical tension whose parameters were 120 min/day, 1 Hz, and 5% strain. After 2 weeks of culture, MSCs under cyclic tension showed more regularly oriented alignment and lower expression of CD73 and CD105 than control by microscopy and FACS analysis. In transcriptional level, type I collagen, type II collagen, fibronectin, elastin, α-smooth muscle actin mRNA expressions of MSCs under cyclic tension were higher than control and similar to native ACL. In conclusion, it is thought that mechanical cyclic tension induced the loss of stemness of MSC, therefore improved the differentiation into ACL fibroblast-like cell.