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.

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.

가토에서 일측 요관 부분 및 완전폐색시 신장과 요관의 조직학적 변화

김상현,김용웅,육승모,한동석,노안식,임재성,김홍식,나용길,설종구 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

This study was designed to clarify histologic changes in the experimental rabbit kidney and ureter after unilateral partial or complete ureteral obstruction. A total of 20 adult white rabbits were divided into 4 subgroups in the partial obstruction followed by 2 weeks, the partial obstruction followed by 4 weeks, the complete obstruction followed by 2 weeks, and the complete obstruction followed by 4 weeks. The normal control group was consisted of 5 adult white rabbits. The kidneys and ureters for light microscopy were fixed in 10% neutral formalin, embedded in paraffin and stained with hematoxylin and eosin. Abnormal histologic fingings showed in ipsilateral kidney and ureter of all subgroups(such as dilatation of uriniferous tubule, focal necrosis and desquamation of epithelium, interstitial fibrosis, glomerular congestion, widening of Bowman's space, dilatation of ureter, epithelial cell atrophy or loss, interstitial fibrosis and interstitial inflammation). These findings were most severe in the group of the complete-obstructed ureter for 4 weeks. No significant changes showed in contralateral ureter of all subgroups. The degree of obstruction was severe and period of obstruction was long, the histological changes in ipsilateral side were severe. Despite of changes in ipsilateral side no abnormal findings showed in contralateral side. We suggest that long term experimental investigation of histologic changes in ipsilateral side and compensatory changes in contralateral side have to be studied.

식이섬유 보충용 식품의 섭취에 따른 여성의 비만관련 체구성 요인 및 배변만족도의 변화

임용택,강선영,김재등,김성수,김재우,이충영,김정모 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.1

The Purpose of this study was to investigate the effect of functional food including dietary fiber supplementation on body composition concerning obesity and defecation satisfaction of women. Twelve young healthy women but had defecation difficulty were participated as a subject. Body weight, %body fat, WHR mesurement and defecation satisfaction questionnaire were performed before and after 2 weeks' supplementation. The results of this study were as follows : First, Body composition concerning obesity such as body weight(p=.0065), % body fat(p =.0004) and WHR(p=.0007) after 2 weeks' functional food including dietary fiber supplementation was decreased significantly. Second, defecation satisfaction functional food including dietary fiber supplementation was increased significantly(p = .0039). This results suggested that functional food including dietary fiber supplementation should be recommended as effective dietary food for persons with obesity and defecation difficulty.

중추성 요붕증으로 발현된 랑거한스세포 조직구증식증 1례

김준성,윤원상,김근모,최영권,박기원,김병희,유용상 대한소아내분비학회 2004 Annals of Pediatirc Endocrinology & Metabolism Vol.9 No.1

만성 승모판 패쇄부전증 환자에서의 안지오텐신 전환효소 억제제의 장기 투여 효과

김대희,이명묵,이해영,조현재,박승정,서재빈,서정원,양한모,윤창환,조상호,이준희,김용진,김명아,손대원,오병희,박영배 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

창의력 개발을 위한 초등실과 교수·학습자료의 개발

김용익,박행모,방기혁 光州敎育大學校 初等敎育硏究所 2002 初等敎育硏究 Vol.17 No.-

The purpose of this study was to develop instructional materials for the development of creativity through practical arts subject. This study was carried out mainly through literature review. The concept of creativity was organized as creativity domain(X axis) including cognitive and affective one, creativity dimension(Y axis) including historical creativity and psychological creativity, and the viewpoint of creativity level(Z axis) including novelty and appropriateness. In the future, creativity education in practical arts subject should be more emphasized because of creativity development education through practical arts subject was more effective than through other subjects. Most of preceding researches related to creativity in practical arts subject dealt with instructional model and guidance for creativity rather than development of various instructional materials. This study explored Treffinger's instructional model which was composed of difficulty finding, data finding, problem finding, solution finding, and acceptance finding. And, Instructional guidance plan related to 'woodworking lesson' was made at base of the model. Besides, other instructional materials for the improvement of creative thought was concretely presented. Finally, it was suggested that more instructional materials should be developed and a test for effectiveness of such a creative program should be made afterward.

지방분권과 지역언론 활성화방안 연구

김덕모,조용철 호남대학교 2005 호남대학교 학술논문집 Vol.26 No.1

According to the launching of participation government, decentralization of power and balabced development of land are uprised as a vital national agenda and diverse discussions are under way actively. Meanwhile evils of localism and Seoul-Metropolitan area based national development strategies put the local far away. So the sense of alienation of local reached the top of a boiling pot. The government of Ro Moo Hyun's plan for decentralization of power and balabced development of land cast a vision of revolutional change in the field of all arena such as politics, economy, society and culture. For that reason, local newspaper (which is the locomotive of local development) is said that he has to be changed more dynamically than ever before. Sprouting of colorful discussions about decentralization of power and measurements of the vitalization of local newspaper after the launching of participation government attribute to that stream. These discussions include institution practices which is accumulated during so many years, changes of media environment and awakening of local pressmen and residents. Now local press is cinfronted with serious agony whether they are making a role of agenda setting for decentralization of power and balanced development of land. In this respects, Gwangju-Jeonnam based newspaper's first page change (top news of each news paper is different from another newspaper) is accepted as positive which reflect the diversitied of society, But critic criticised megative aspects that diversity does not reflect many color of market of public opinion but promotes the disintegration of public opinion. This study aims at trying to find a solution to a problem of what is the better way and measurement to reform local newspaper. To find a solution to a problem, bibliographic research and statistical analysis approach are used here.

R·C SLAB의 炭素織維 SHEET 補强效果에 關한 硏究(1)

모귀석,김용선 대불대학교 1999 論文集 Vol.5 No.1

An experimental study was conducted to determine the effect of reinforced concrete slab with carbon fiber sheet. A structure that was already in place was used, and ten reinforced concrete slab specimens of variable concrete compressive An experimental study was conducted to determine the effect of reinforced strengths and reinforcing methods were fabricated. One was loaded up using a live load while the others were loaded up to failure point to explore the applicability of the structures. The test results showed that the reinforcing method using bond strength is not effective in structures with low concrete compressive strength because of the concrete aeration.

실과 전담교사 교육 프로그램 개발을 위한 기초연구

김용익,박행모,방기혁 광주교육대학교 초등교육연구소 2001 初等敎育硏究 Vol.16 No.1

The purposes of this study were to justify the need of exclusive responsibility teachers in elementary practical arts subject, and to investigate the actual conditions and problems of practical arts' teacher education. This study was carried out through review of literature and questionnaire survey. The results of this study were as follows; 1)The need of exclusive responsibility teachers in elementary practical arts subject was could be justified in the aspect of social specified trend, special character of practical arts, and use of machine and equipment facilities. 2)Natural disposition needed for exclusive responsibility teachers in elementary practical arts subject was identified as possession of firm belief toward practical arts' philosophy and ideology, enough understanding and competence of practical arts, and complete knowledge and skill of instructional method. 3)The main problems of practical arts' teacher education was identified as the absences of educational goals in program, an unbalance among discipline parts, and the low degree of satisfaction toward teacher education program. 4)Therefore, it is necessary to establish the educational goals of program clearly, to coordinate the discipline parts proportionately, an to recommend and experimentation & practice in teaching and performance assessment.