SHS 공정에 의해 제조된 Mo_xW_1-xSi₂ 발열체의 열화메커니즘

이동원,이상헌,김용남,이성철,구상모,오종민,Lee, Dong-Won,Lee, Sang-Hun,Kim, Yong-Nam,Lee, Sung-Chul,Koo, Sang-Mo,Oh, Jong-Min 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.10

The degradation mechanism of $Mo_xW_{1-x}Si_2$ ultrahigh-temperature heating elements fabricated by self-propagating high-temperature synthesiswas investigated. The $Mo_xW_{1-x}Si_2$ specimens (with and without post-annealing) were subjected to ADTs (accelerated degradation tests) at temperatures up to $1,700^{\circ}C$ at heating rates of 3, 4, 5, 7, and $14^{\circ}C/min$. The surface loads of all the specimen heaters were increased with the increase in the target temperature. For the $Mo_xW_{1-x}Si_2$ specimens without annealing, many pores and secondary-phase particles were observed in the microstructure; the surface load increased to $23.9W/cm^2$ at $1,700^{\circ}C$, while the bending strength drastically reduced to 242 MPa. In contrast, the $Mo_xW_{1-x}Si_2$ specimens after post-annealing retained $single-Mo_xW_{1-x}Si_2$ phases and showed superior durability after the ADT. Consequently, it is thought that the formation of microcracks and coarse secondary phases during the ADT are the main causes for the degraded performance of the $Mo_xW_{1-x}Si_2$ heating elements without post-annealing.

Effect of post annealing on the microstructure, mechanical properties, and failure of Mo_xW_1-xSi₂ heaters produced by self-propagating high-temperature synthesis

Cho, Myung-Yeon,Lee, Sung-Chul,Park, Chulhwan,Lee, Daeseok,Koo, Sang-Mo,Moon, Kyoung-Sook,Lee, Dong-Won,Oh, Jong-Min Elsevier 2019 INTERMETALLICS Vol.110 No.-

<P><B>Abstract</B></P> <P>High-performance tungsten molybdenum disilicide (Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB>) heating elements were prepared using a self-propagating high temperature synthesis process. The effect of post annealing on the degradation behavior of the alloy was experimentally investigated. Increasing the attrition milling time up to 20 min during powder preparation resulted in Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters with the highest density, which increased the fracture strength compared to samples with shorter attrition times. Such samples were annealed and evaluated as heating elements using accelerated degradation tests and failure analysis in order to compare their structural characteristics and flexural strength with as-fabricated samples. The annealed Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heater showed a relatively dense structure with few pores and no secondary phases, apart from a SiO<SUB>2</SUB> layer. This favorable structure prevented bubble formation, which can result in fracturing of the heater, as revealed by evaluation at high temperatures with various heating rates. The flexural strength of the annealed specimen was 2.5-times higher than that of the as-fabricated specimen, which was attributed to removal of secondary phases during annealing. Failure time and surface load analyses were used to investigate the fracture mechanism of the Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters in detail at 1790 °C by quantifying bubble formation and the presence of secondary phases.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Self-propagating high temperature synthesis of Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters demonstrated. </LI> <LI> Post-annealed Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si<SUB>2</SUB> heaters were highly dense, with good flexural strength. </LI> <LI> Bubble formation (the main cause of fracture) suppressed at ultra-high temperature (above 1700 °C). </LI> <LI> Surface load, failure time, and bubble formation used to study fracture mechanisms. </LI> </UL> </P>

SHS 공정으로 제조된 Mo<SUB>x</SUB>W<SUB>1-x</SUB>Si₂ 발열체의 가속수명시험과 고장분석

이동원(Dong-Won Lee),이상헌(Sang-Hun Lee),김용남(Yong-Nam Kim),이희수(Heesoo Lee),이성철(Sung-Chul Lee),구상모(Sang-Mo Koo),오종민(Jong-Min Oh) 한국전기전자학회 2017 전기전자학회논문지 Vol.21 No.3

고온자전합성과 후열처리 공정으로 MoxW1-xSi₂ 발열체를 제조하였다. MoxW1-xSi₂ 발열체의 신뢰성을 검증하기 위해 가속수명시험을 수행하였으며, 수명시간을 Minitab 프로그램으로 추정하였다. 또한, 가속수명시험 후의 MoxW1-xSi₂ 발열체의 고장분석을 전기적과 구조적 특성으로부터 수행하였다. 그 결과, MoxW1-xSi₂ 발열체의 지배적인 고장 유형은 발열체 내부의 크랙 형성과 SiO₂ 보호층의 박리임을 확인하였다. MoxW1-xSi₂ heaters were fabricated by self-propagating high-temperature synthesis (SHS) process and post sintering process. To validate the reliability of the MoxW1-xSi₂ heaters, the accelerated life test (ALT) was conducted, and then lifetime to MoxW1-xSi₂ heaters was estimated by using Minitab programs. Also, the failure analysis of MoxW1-xSi₂ heaters after ALT was performed through electrical and structural properties. As the results, it was confirmed that the dominant failure mode of MoxW1-xSi₂ heaters is the crack formation in heaters and the delamination of protective SiO₂ layers.

염상섭 초기 소설의 변화 과정 고찰 -매체와의 상관성을 중심으로-

이희정 ( Hee Jung Lee ),김상모 ( Sang Mo Kim ) 한민족문화학회 2011 한민족문화연구 Vol.38 No.-

본고에서는 염상섭 초기 소설의 변화 과정을 고찰하면서 근대 초기 작가의 주 무대였던 ``매체``와 작품과의 상호영향에 특히 주목했다. 기존의 연구에서는 염상섭 초기소설의 변화 양상을 크게 ``내면적인 것에서 실제 현실에 대한 관심으로의 이동``이라는 측면에서 파악하였다. 그리고 이러한 변화의 내적 동인을 작가의 세계관의 변화라는 측면에서 분석하고 있다. 그런데 근대 초기의 작품들이 대부분 잡지와 신문을 통해 발표되었고, 이로 인해 작가들의 작품이 발표매체들과의 상호 영향 속에서 형성되었다는 점을 고려할 필요가 있다. 이 때 기존의 논의에서 좀 더 나아가 염상섭 초기 작품의 전개과정에 끼친 매체의 영향력을 짚어 볼 수 있다. 이러한 관점에서 본고에서는 『개벽』을 통해 발표된 염상섭의 작품이 당시 『개벽』이라는 잡지의 매체적 특성과 상호영향을 주고 받았으며, 이후 『동아일보』에 소설을 연재한 경험이 다시 『개벽』에 게재한 「금반지」와 「검사국대합실」의 창작에 많은 영향을 주었던 것을 밝히고자 했다. 형식적인 측면에서 볼 때 초기 소설에서는 한자가 남발되고 일본식 번역투의 문장이 나타났으나, 「금반지」와 「검사국대합실」에서는 이러한 것들이 거의 사라졌다. 내용적으로도 초기에 강하게 나타났던 내면에의 천착이 이후 풍속에 대한 관심으로 전환되었다. 이러한 현상은 바로 염상섭의 신문매체의 경험을 통해 이뤄진 것임을 알 수 있다. Existing studies grasped the changes of initial novel trend of Yeom Sang-Seop largely in the aspect of ``shift from internal things to the concern to actual reality``. Also, they analyzed inner motive occurring such change focused on the change of his view to the world. However, the part this article emphasizes is a mutual influence between ``media`` which was main stage of works for writers in the early of modern times and works. Works in the early of modern times were mostly published via magazines and newspapers, and due to this, writers` works were finally formed within mutual influences of publishing media. Even the progress of initial works of Yeom Sang-Seop was also influenced absolutely by such media. The work published via [Gaebyeok] was mutually influenced with media characteristics of magazine. Since then, the experience of Yeom to publish novel serially to [DongA Daily] effected much on the creation of [Gold Ring] and [Lobby of Investigation Bureau] published again on [Gaebyeok]. Overuse of Chinese characters and Japanism sentences which were shown on his initial works were mostly not shown on [Gold Ring] and [Lobby of Investigation Bureau]. Also, it can be said that the switch from detailed exploration to inner side to the concern to customs was made from his experience to such media including newspapers.

Phenotype evaluation of a large-scale CRISPR/Cas9-mediated gene-edited rice population

Yurim Kim,Sieun Choi,Song Lim Kim,Sang Ryeol Park,In Sun Yoon,Jiheon Han,Hayeong Lee,Yeeun Jun,Soonhwa Kwak,Hosun Cheon,Youngjun Mo1 한국육종학회 2023 한국육종학회 공동학술발표집 Vol.2023 No.-

해남 모이산 천열수 금은광상의 지구화학적 특성

문동혁,고상모,이길재,Moon, Dong-Hyeok,Koh, Sang-Mo,Lee, Gill-Jae 대한자원환경지질학회 2010 자원환경지질 Vol.43 No.5

전남 해남군 모이산 금광상에서 지구화학적 특성에 대한 연구를 수행하기 위하여 모이산 지표 및 갱내, 대산 지표에서 채취한 총 140개 시료에 대한 지구화학분석결과를 상관분석, 요인분석 그리고 군집분석 등 다변수 통계처리 하였다. 상관분석 결과, 금의 함량이 100 ppb 미만인 비광화대와 100 ppb 이상인 광화대에서 동시에 금과 높은 상관관계를 가지는 원소는 Ag, Cu, Bi, Te 등이며, 이는 연구지역에서 수반되는 함금 은 광석광물들(엘렉트럼, 실바나이트, 칼라버라이트 및 스퉤자이트)과 기타광석광물들(황동석, 텔룰로비스무타이트 및 비스무시나이트)의 산출과 일치된 결과로 인지된다. Mo은 비광화대(0.269)에서 보다 광화대(0.615)에서 상대적으로 높은 상관계수를 가지므로 금광화작용에 의해 그 함량이 강하게 지배되고 있는 것으로 해석된다. Mn, Cs, Fe, Se 등은 비광화대에서는 금과 정의 상관관계를 가지지만 광화대에서는 음의 상관관계를 가지므로 금광화작용 시 모암으로부터 용탈되는 원소군으로 해석된다. Sb은 광화대에서 금과 높은 상관성을 보이지만 비광화대에서는 음의 상관관계를 가지므로 금광화작용 시 부화되는 원소로 지시될 수 있다. 요인분석결과, 비광화대에서 금의 함량에 영향을 받는 요인군에 속하는 원소는 Se, Ag, Cs, Te 등이며 이들은 연구지역 내 비광화대에서 금의 존재 여부를 알려줄 수 있는 원소로 해석될 수 있다. 반면 광화대에서는 Mo과 Te 등이 강하게 금광화작용의 여부를 지시해 주며, 금과 함께 수반되는 은광화작용의 여부를 지시해 줄 수 있는 원소는 Sb과 Cu 등으로 해석된다. 군집분석 결과 비광화대에서 Cd-Zn-Pb-S, Bi-Fe-Cu-Mn, Se-Te-Au-Cs-Ag, As-Sb-Ba 등이 유사한 거동을 보이는 원소군으로 나타나는 반면, 광화대에서는 Cd-Zn-Mn-Pb, Fe-S-Se, As-Bi-Cs, Ag-Sb-Cu, Au-Te-Mo 등이 유사한 거동을 보여주는 원소군으로 나타난다. 이상과 같은 지구화학분석 자료의 다변수 통계처리를 이용하여 금광화대와 비광화대의 산출광물의 거동 및 지구화학적 특성 차이의 비교가 가능하므로 추후 이러한 방법이 이와 유사한 유형의 광상탐사에 유용한 방법으로 적용될 수 있을 것으로 기대된다. Geochemical characteristics of the Moisan epithermal gold-silver deposit with total 140 samples in Haenam area, Jeollanamdo were studied by using multivariate statistical analysis (correlation analysis, factor analysis and cluster analysis). The correlation analysis reveals that Ag, Cu, Bi, Te are highly correlated with Au in the both non-mineralized and mineralized zone. It is resulted from the presence of Au-Ag bearing minerals (electrum, sylvanite, calaverite and stuezite) and non Au-Ag containing minerals (chalcopyrite, tellurobismuthite and bismuthinite). Mo shows relatively much higher correlation at the mineralized zone (0.615) than non-mineralized zone (0.269) which implies Mo content is strongly affected by Au-mineralization. While Mn, Cs, Fe, Se correlated with Au at the nonmineralized zone, they have negative correlation at the mineralized zone. Therefore, they seem to be eluviated elements from the host rock during gold mineralization. Sb is enriched during the gold mineralization showing high correlation at the mineralized zone and negative correlation at the non-mineralized zone. According to the factor analysis, Se, Ag, Cs, Te are the indicators of gold mineralization presence due to the strong affection of gold content in the non-mineralized zone. In the mineralized zone, on the other hand, Mo, Te and Sb, Cu are the indicators of gold and silver mineralization, respectively. While the cluster analysis reveals that Cd-Zn-Pb-S, Bi-Fe-Cu-Mn, Se-Te-Au-Cs-Ag, As-Sb-Ba are the similar behavior elements groups in the non-mineralized zone, Cd-Zn-Mn-Pb, Fe-S-Se, As-Bi-Cs, Ag-Sb-Cu, Au-Te-Mo are the similar behavior elements groups in the mineralized zone. Using multivariate statistical analysis as mentioned above makes it possible to compare the behavior of presented minerals and difference of geochemical characteristics between mineralized and non-mineralized zone. Therefore, it will be expected a useful tool on the similar type of mining exploration.

Poster Ⅱ : Part D : Prokaryotic Gene Expression ; Secretion of Foreign Protein Using the Glucose - resistant Mutant amyR₂ Promoters in Bacillus subtilis

Sung Il Kim,Jin Mo Kim,Se Yong Lee 생화학분자생물학회(구 한국생화학분자생물학회) 1991 추계학술대회집 Vol.- No.-

Session F : Eukaryotic Gene Structure and Expression : EXPRESSION AND FUNCTIONAL ANALYSIS OF YEAST ARS BINDING FACTOR Ⅰ GENE AND ITS MUTANT GENES IN YEAST

Sang Kyung Lee,Gi Nam Cho,Gu Hung Jung,Hyune Mo Rho,Ji Young Kim 생화학분자생물학회(구 한국생화학분자생물학회) 1993 추계학술대회집 Vol.- No.-

Enhancement of CH4-water mass transfer using methyl-modified mesoporous silica nanoparticles

Sung-Yeob Lee,Kyo-Sung Mo,최진하,허남회,오병근,이진원 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.9

Surface-modified mesoporous silica nanoparticle (MSN) with methyl groups was used to enhance the CH4-water volumetric mass transfer coefficient (kLa) and the solubility of CH4 in water. Two types of samples were tested: unmodified MSN and methyl-modified MSN. The mass transfer for each type of sample was measured every 20 s by gas chromatography. The results showed that the methyl-modified MSN, which have both hydrophobic and hydrophilic properties on the surface, exhibited higher CH4-water volumetric mass transfer coefficient and solubility in water. The dissolved concentrations of CH4 were enhanced by 10.7% and 27.8%, and the volumetric mass transfer coefficient were enhanced by 28.6% and 84.7%, respectively, by using unmodified MSN and methyl-modified MSN.

Characterization of Plant Growth Promoting Potential of Bacillus Sp. LKE15 Culture Filtrate on Host Plants Via Phytohormonal Interaction

Sang-Mo Kang,Ramalingam Radhakrishnan,Ko-Eun Lee,Seok-Min Lee,Yeon-Gyeong Park,Ah-Yeong Kim,Chang-Woo Seo,In-Jung Lee 한국원예학회 2015 한국원예학회 학술발표요지 Vol.2015 No.5