브레이징 온도 변화에 따른 ZrO2와 Ti-6Al-4V의 접합 특성

기세호,박상윤,허영구,정재필,김원중 大韓齒科補綴學會 2012 대한치과보철학회지 Vol.50 No.3

Purpose: In this study, brazing characteristics of ZrO2 and Ti-6Al-4V brazed joints with increasing temperature were investigated. Materials and methods: The sample size of the ZrO2 was 3 mm × 3 mm × 3 mm (thickness), and Ti-6Al-4V was 10 mm (diameter) × 5 mm (thickness). The filler metal consisted of Ag-Cu-Sn-Ti was prepared in powder form. The brazing sample was heated in a vacuum furnace under 5 × 10-6 torr atmosphere, while the brazing temperature was changed from 700 to 800℃ for 30 min. Results: The experimental results shows that brazed joint of ZrO2 and Ti-6Al-4V occurred at 700 - 800℃. Brazed joint consisted of Ag-rich matrix and Cu-rich phase. A Cu-Ti intermetallic compounds and a Ti-Sn-Cu-Ag alloy were produced along the Ti-6Al-4V bonded interface. Thickness of the reacted layer along the Ti-6Al-4V bonded interface was increased with brazing temperature. Defect ratios of ZrO2 and Ti-6Al-4V bonded interfaces decreased with brazing temperature. Conclusion: Thickness and defect ratio of brazed joints were decreased with increasing temperature. Zirconia was not wetting with filler metal, because the reaction between ZrO2 and Ti did not occur enough. 연구 목적: 온도 변화에 따른 ZrO2와 Ti-6Al-4V의 접합 특성에 대해 알아보기 위하여 새로운 브레이징 합금을 제조하고, 브레이징 온도가 접합 특성에 미치는 영향에 대하여 조사하고자 하였다. 연구 재료 및 방법: 본 연구에서 사용된 시편으로는 실험용 ZrO2 모재(ZirBlank-PS, Acucera, Inc., Gyeonggi-do, Korea)는 소결 전의 블록형태(65 mm × 36 mm × 12 mm (t))이며, 이를 잘라 사포(#2400)로 표면연마 후 소결하였다. 소결된 ZrO2 시편의 크기는 3 mm × 3 mm × 3 mm (t) 이다. Ti-6Al-4V 모재(Ti 6Al 4V ELI CG Bar, TMS, Washington, USA)는 직경 10 mm × 5 mm (t)를 사용하였다. 소결된 ZrO2와 Ti-6Al-4V의 접합을 위하여 브레이징 합금을 제조하였다. 시편을 3군으로 나누어A군은 700℃에서, B군은 750℃에서, C군은 800℃에서 각각 브레이징 하였다. 브레이징 부의 두께와 결함율의 측정은 각 군당 하나의 시편으로 각 시편 당 5회씩 반복 측정하여 평균값을 취하였다. 결과: 브레이징 합금을 사용하여 진공 브레이징을 수행한 결과 ZrO2 와 Ti-6Al-4V 는 700℃ - 800℃에서 양호한 접합을 보였다. 브레이징 후 브레이징 온도 변화에 따른 브레이징 부의 두께 및 결함율의 변화는SEM을 사용하여 측정하였다. 브레이징 온도가 700℃에서 800℃로 증가함에 따라 CuTi 금속간 화합물 층 및 Ti-Sn-Cu-Ag계 화합물 층의 두께는 각각 4.5 ㎛에서 10.3 ㎛로, 3.1 ㎛에서 5.0 ㎛로 증가되었다. 또한 브레이징 온도가 700℃에서 800℃로 증가함에 따라 브레이징 접합계면의 결함율은 ZrO2 및 Ti-6Al-4V 계면에서 각각25%에서 16.3%, 5%에서 1.5%로 감소되었다. 결론: 브레이징 온도가 700℃에서 800℃로 증가됨에 따라, 브레이징 접합계면의 결함율은 ZrO2 및 Ti-6Al-4V 계면에서 모두 감소되었다. 이는 결함부에서 ZrO2와 활성원소인 Ti과의 반응이 충분히 일어나지 않아서 브레이징 합금이 ZrO2에 웨팅되지 않은 것이 원인이라고 사료된다.

관상동맥 시술 도중 발생한 좌주간부 관상동맥 박리에 대한 스텐트 삽입 치료의 단장기 임상 결과 : acute and long-term results

이세환,이승환,홍명기,김영학,이철환,한기훈,송종민,강덕현,송재관,김재중,박성욱,박승정 대한내과학회 2004 대한내과학회지 Vol.66 No.6

목적 : 심도자 사용 시술과 관련된 좌주간부 관상동맥박리에 대한 적절한 치료는 아직 확실히 정립되지 않은 상태이다. 이에 본 연구는 좌주간부 관상동맥 박리에 대한 스텐트 삽입술의 단장기 임상결과를 후향적으로 분석하였다. 방법 : 좌주간부 관상동맥 박리에 대한 치료로 즉각적인 스텐트 삽입술을 시행하는 것이 안전하고 효과적인 방법임을 가설하였고, 이러한 즉각적인 스텐트 삽입을 시행한 10명의 환자를 대상으로 단장기적 임상경과를 의무기록 고찰과 전화 면담을 통해서 평가하였다. 결과 : 전체 환자 모두 처음부터 좌주간부 관상동맥에 유의한 협착을 가진 환자는 없었으며, 8명의 환자는 심도자의 조작으로 인한 박리가 발생한 경우였고(진단적 혈관 조영술 중에 3명, 유도 도자 조작 중에 5명), 나머지 2명은 다른 병변에 스텐트 삽입시술을 하는 중에 박리가 발생하였다. 이 10명의 환자에서 모두 즉각적인 스텐트 삽입술이 시행되었고, 4명의 환자에서 시술 도중 혈압 저하로 Intra-aortic Ballon Pump (IABP)를 장착하였다. 모든 환자에서 성공적으로 스텐트가 삽입되었고, 병원내 사망은 1명도 없었다. 6개월 추적 관상동맥 조영술은 8명의 환자에서 시행되었다. 혈관 조영상의 재협착(직경 협착 50% 이상)은 8명 모두에게서 관찰되지 않았으며, 퇴원 후 평균 31±25개월의 추적관찰 결과 주요 심장사건은 1건도 발생하지 않았다. 결론 : 비록 대상 환자가 적은 연구였지만 좌주간부 관상동맥 박리에 대한 스텐트 삽입술은 기술적으로 안전하고 빠르게 시행 할 수 있으며, 훌륭한 단장기적인 치료 효과를 보여준다. Background : The optimal treatment of patients with left main coronary artery (LMCA) dissection during catheter-based procedure remains uncertain. We retrospectively analyzed the acute and long-term results of bail-out stenting for LMCA dissection. Methods : In cases with significant LMCA dissection occurring during catheter-based procedure, prompt stent implantation may be safe and associated with favorable clinical outcome. We evaluated the acute and long-term results of bail-out stenting for LMCA dissection occurring during catheter-bases procedure in 1- patients. Results : Initially, there was significant stenosis of LMCA segment in these patients. Catheter-induced dissection occurred in 8 patients (during diagnostic angiography in 3 patients and guiding catheter manipulation in 5 patients). Two patients suffered dissection in the setting of stent deployment in other vessels. Therefore, bail-out stenting LMCA dissection was performed in a total of 10 patients. In 4 patients, hypotension developed and intra-aortic balloon pump was placed during procedure. Stents were successfully deployed in all patients. There was no in-hospital mortality. Six-month angiographic follow-up was performed in 8 patients. Angiographic restenosis(diameter stenosis 50%) was not observed in all patients at follow-up study. During a mean follow-up of 31±25 months after hospital discharge, there was no major adverse cardiac event (death, myocardial infarction, and target lesion revascularization). Conclusion : Bail-out LMCA stenting is technically feasible, and showed good acute and long-term results in a small series of patients.

휴대용 계산기에 의한 착물의 안정도상수의 계산

윤세중,오제직,박병빈,박성록 공주대학교 사범대학 과학교육연구소 1980 과학교육연구 Vol.12 No.1

A Pocket calcultor program(Texas Instruments TI58 or TI59) was constructed for evaluation of the Successive stability constants of Nikel-glycine complex. This program conld be used for many other systems having similar eguhibrium scheme and experimental method. TI59, this program could be extended to the calculation of ionic strength correction and high n Complexes.

지구과학 학습용 Computer program 연구 : 고등학교 지구과학Ⅰ 제1단원을 중심으로 Centering around the First Unit of Highschool Earth Science Textbook Ⅰ

尹世重,金在炫,崔錫源 공주대학교 사범대학 과학교육연구소 1984 과학교육연구 Vol.16 No.1

A Computer program which could be used for teaching material in new curriculum of highschool earth science course was programed with Goldstar Co. model FC-100 personal computer in BASIC language. The main contents of this program are calculation of radius, mass, average density, the acceleration of gravity of earth and evidences for rotation of earth etc. All these substances are explained with Korean or English and by means of derivation of formula, calculation or dynamic graphs.

TLC 검출의 適用硏究 : 環境科學 敎材硏究 A Teaching Material of Environmental Science

尹世重 공주대학교 사범대학 과학교육연구소 1977 과학교육연구 Vol.9 No.1

微量成分을 分離하고 確認하는데 여러가지 方法이 있지만, 그 중에서도 學生實驗敎材로 적합한 것으로는 chromatography를 들 수 있다. 특히 paper partition chromatography와 thin layer chromatography(TLC)는 실험이 간편하고 活用범위가 넓고, 많은 학생들에게 일일히 실험 시킬 수 있고, 時間을 유효하게 활용할 수 있고, 또 費用이 많이 들지 않기 때문에 널리 활용될 수 있는 方法이다. TLC는 paper partition chromatography와 거이 같은 내용의 조작을 하면서도, 전展開시간이 짧고 分離가 선명하게 잘 된다는 利點이 있다. 짧은 시간에 많은 학생이 하는 實驗敎材로 아주 훌륭하다. 이 實驗은 TLC를 활용하여, 微量으로도 生理的으로 活性인 alkaloid, caffeine에 대하여 여러가지 溶媒에 따라 Rf값을 측정하여 용매와 試料사이의 상관관계를 알아보고, 각종醫藥品과 市販되는 飮料水에서 caffeine 성분을 檢出해 내는데 適用시켜 보았다. 이를 통하여 TLC 적용의 技術뿐만 아니라, 溶媒의 極性에 따르는 시료의 分配原理를 익힐 수 있도록 시도해 보았다. Thin Layer Chromatography(TLC) is an excellent method for detection and separation of trace amounts of component. Because of shorter running time, clear detection, versatile application, and inexpensiveness, it can be available for non-major students experiment in college and for major students as well. In this experiments, the Rf values were measured when run with various solvents and observed the relationship on the partition of samples against solvents. Caffeine was detected from several drugs and commercial of samples against solvents. Caffeine was detected from several drugs and commercial soft drinks. This would be a base for detection of other biological active pollutants as well as an alkaloid. The Rf value of caffeine was largest in solvent which has a intermediary polarity such as chloroform, and was smallest in solvent which has either larger polarity or nothing such as ethanol or cyclohexane. The best solvent for detection of caffeine from samples was a mixed solvent, chloroform-ethylacetate 1:1 by volume.

조영 심초음파

임세중 대한의사협회 2003 대한의사협회지 Vol.46 No.11

中學校 科學科의 實驗實習 敎材의 開發硏究(Ⅲ)

尹世重,趙泰璟,吳濟直,金溫植,金黎相 공주대학교 사범대학 과학교육연구소 1983 과학교육연구 Vol.15 No.1

Teaching materials available for the effective performance of laboratory exp-erimental work in middle school were developed: Physics part ; A measuring apparatus of uniformly accelerated motion and normal force of inclined plane was developed. Chemistry part ; An imploved Eudiometer applicable in measuring reaction mole ratio and usful for a gas generating apparatus was developed. Biology part ; convenient teaching materials observing law of dominance, law of segregation, law of independence, incomplete dominance and dihybrid cross were developed. Earth science part ; A laboratory teaching materials observing formation of wave, current and graded bedding, and identification of sedimentary rocks were developed. Putting the above results of study together, the integrated suggestions were made to the effective development of science education in middle school : 1. The contents of science textbook should be simplified to the direction of the understanding of essential principles and concept. 2. The development and dirtrihbution of various supplementary teaching materials (film, T.P., cassettes film, supplementary textbook, program teaching materials individual learning materials) are required. 3. The experimental laboratory should be equipped with common instruments and equipements. 4. Efforts and time are needed to science teachers, and so remission of sundry duties and arrangement of assistant are hopefully considered. 5. Teacher's research activities should be encouraged by administrative route or relevant institute.

질량 명사와 가산 명사의 전환에 따른 영어 관사 용법

김세중 단국대학교 1998 論文集 Vol.33 No.-

The aim of this dissertation is to answer the following questions so often asked by adult language learners of English: (a) in which case do we use the? (b) in which case do we use a(n)? (c) in which case do we use Φ­­before nouns. This dissertation deals with what are the signals for the occurrence of the articles ―a(n), the, Φ―before nouns. This study discusses sho to distinguish count couns from mass ones and what makers an NP definite and what makes it indefinite. It also discusses the generic use of the English articles. This dissertation puts great emphasis on the best way to convert a mass noun into a count noun and vice versa. Five principles are presented for mass/count conversion. The best plausible signals for the English articles are found to be existence, uniqueness and familiarity Subtle differences among the generic use of the, a(n) and Φ are discussed and their respective distributions and restrictions are suggested. An over-all system of article usage is presented for learners of English as a foreign language.

의미와 번역 : 영어와 한국어 수사 의문문의 비교 연구를 중심으로 A Comparative Study on Translating Rhetorical Questions in English and Korean

金世中 한국영어교육연구학회 1998 영어교육연구 Vol.- No.18

It is true that there are many problems, conflicts and difficulties with which the translator is confronted in the process of translation. In these viewpoints the end of this paper is to deal with "function" with due regard to contexts and extralinguistic elements other than the style and form of language, especially when translating rhetorical questions in English and Korean. This paper is concerned with the definition of a rhetorical question and the classification of the function of those in English and Korea in order to know what is needed for the reproduction and transformation of the source language text. In conclusion, it is, to say the least, necessary that the function of a sentence be transformed considering the extralinguistic elements in translating, since language has both the meaning of structure and that of society, culture and function.

美國大學에서의 環境科學(環境硏究) 敎育의 現況分析과 適用

尹世重 공주대학교 사범대학 과학교육연구소 1982 과학교육연구 Vol.14 No.1

Contemporary education of environmtal study in the university of the United StStates was survayed. More than half of the sample universities have established the major or minor system on it. The author suggests that appropriate courses on environmental study should be provided at universities and be elected the course more than eighteen credits by students who are interested to be an environmental specialist.