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.

특발성 자발성 신장 파열 1예

윤재철,김원,조규종,홍정석,이미우,장성은,오세현,임경수 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Primary aldosteronism is a syndrome characterized by hypertension, hypokalemia, suppressed plasma renin activity, and elevated serum aldosterone levels. Conn first described it 1955 in association with adrenal cortical adenoma(Conn's syndrome). Today, it can be divided into at least six distinctive sub-groups. The diagnosis of primary aldosteronism is usually suspected when the patient presents with poorly controlled hypertension with hypokalemia. The main issues in the evaluation of primary aldosteronism are to differentiate an adenoma from hyperplasia and to localize the adenoma. Basic hormonal studies and computed tomographic(CT) scanning can be used effectively for that differentiation. An adenoma is one of a few potentially curable forms of hypertension, and it is best treated by removing the adrenal tumor. We experienced a case of a typical adrenal adenoma. The patient was a 37-year-old male who had experienced in both his legs over a period of several days a weakness due to hypokalemia. He was diagnosed using basic hormonal studies and adrenal CT scanning. After, he received laparoscopic adrenalectomy and was discharged with improved condition.

인발 성형 공정을 이용한 carbon-glass hybrid composite 제작

박상윤,최원종,강길호,문초록,김세영 한국항공대학교 항공우주산업기술연구소 2002 航空宇宙産業技術硏究所 硏究誌 Vol.12 No.-

단면이 일정한 구조용 복합재료 제조공정에 널리 사용되고 있는 pultrusion 공정을 이용하여 glass-carbon fiber hybrid composite을 제조하였다. 열분석을 통하여 모재의 경화온도와 경화시간을 분석한 후 금형의 온도와 pulling speed를 결정하였다. 다양한 섬유 비율의 hybrid composite를 제작하였으며 flexural modulus를 측정한 결과 rule of mixture를 이용한 예상치 보다 높은 값을 보였다. Glass-carbon hybrid composite was manufactured by pultrusion process. The major processing conditions such as temperature of heating die and pulling speed have been fixed from thermal analysis results. Hybrid composites with various carbon fiber content were manufactured and flexural modules of each hybrid composite as measured. Compare with rule of mixture, positive hybrid effect was observed.

노랑초파리 ecdysone 결핍 돌연변이(ecd1ts)에서 기능적 ecdysone수용체 구성분의 발현

김세제,박지권,윤원식,이영기,고영상 제주대학교 생명과학연구소 1998 제주생명과학연구 Vol.1 No.-

In Drosophila, the steroid hormone ecdysone triggers the key regulatory cascades controlling the coordinated changes in the developmental pathway of molting and metamorphosis. Ecdysone action is mediated by heterodimer consisting of the ecdysone receptor(EcR) and ultraspiracle proteins(Usp). Heterodimers of these proteins bind to ecdysone response element and ecdsone to modulate gene transcription. In this study, the transcripts of functional ecdsone receptors and ecdysone response genes(Fbp1 and Uro) in ecdysoneless(ecd-1ts) mutation were analyzed by using a RT-PCR and competitive RT-PCR method. The expression of functional ecdysone receptor components were not correlated with tissue-specific ecdysone response genes(Fbp1 and Uro), Suggesting that several other factors involved in the complexity of various ecdysone responses in Drosphila melanogaster. But we showed that the transcripts of EcR-B1 isoforms were expressed with higher level than those of EcR-A in the late third instar larvae of ecdysoneless(ecd-1ts) mutation.

랫드 배양배아에서 ginsenosides가 superoxide dismutase 유전자 발현에 미치는 영향

김재승, 이세라, 김연, 연정민, 백인정, 안병우, 김윤배, 이범준, 윤영원, 남상윤 충북대학교 동물의학연구소 2006 Journal of Biomedical and Translational Research Vol.7 No.2

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염산증기 흡입에 의해 발생한 화학성 폐렴 1예

장재혁,원경준,권세훈,하성일,권용은,이승일,윤성호 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.2

A 38-year-old man with dyspnea admitted to the emergency department after exposure to hydrochloric acid in pharmaceutical product manufacturer. Crackle was auscultated in both lung fields in initial physical examination. Chest radiograph showed consolidation and diffuse parenchymal infiltration in both lung fields. Arterial blood gas analysis showed severe hypoxia. This patient was treated by mechanical ventilation, corticosteroid, antibiotics and bronchodilators and was improved completely in a week after the admission. The authors report a rare case of chemical pneumonitis caused by hydrochloric acid.

Electrical Switching Phenomena in V_2O_5 - TeO_2 Glass Semiconductors

RHEE, Chunghi,YOON, Se Won 慶熙大學校 1974 論文集 Vol.8 No.-

10∼70 mole%를 포함한 몇개의 V_2O_5-TeO_2유리의 電流-電壓 特性이 유리의 組成 成分과 電極사이 간격에 따라서 조사되었다. 유리표면에서 非可逆的인 스윗칭이 한번 일어난 後에는 電壓을 每번 올렸다 내림에 따라 S型. 負性微分抵抗 特性이 再現됨을 發見하였다. 첫번째 스윗칭이 생긴후 形成된 필라멘트가 結晶化 하는 것으로 보아 스윗칭 현상은 不規則的인 유리質 狀態로부터 規則的인 結晶質 狀態로의 相變化와 관계됨을 알수있다. 結晶化된 狀態는 構造가 安定하여 S型 特性을 再現시키며 이 現象은 電子的 過程보다는 熱 果에 현저히 基因하고 있다. Current-voltage characteristic of se-veral V_2O_2-TeO_2 glasses containing 10-70 molar percent V_2O_2 was investigated as a function of composition and electrode separation. It has been found that the irreversible switching phenomenon occurs once on a virgin surface of the glasses and s-type negative differential resis-tance is reproduced in each voltage recycling. Evidence of devitrification of the filament formed after the first switching reveals that the switching action is associated with a phase transi-tion from a disordered glassy-state to an ordered devitrified-state due to self-heating effects. The devitrified state is structure stable and yields a reproducible s-type characueristic, which is attributed predominantly to thermal effects rather than to electronic processes.

마우스 생식기계에 있어서 고려홍삼 추출물이 SOD계 유전자 발현에 미치는 영향

백인정, 연정민, 이세라, 김미라, 김윤배, 이범준, 윤영원, 남상윤 충북대학교 동물의학연구소 2007 Journal of Biomedical and Translational Research Vol.8 No.1

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乳牛에서 驅蟲效果가 泌乳量과 乳脂率에 미치는 效果에 관한 觀察

金泰鍾,李元暢,尹和重,金世寧 건국대학교 1995 學術誌 Vol.39 No.2

The purpose of this study was make an observation on effects of anthelmintics such as Albendazole, Ivomec-F and Nilzan for amount of milk production and milk fat levels before and after administration on Nematoda, Trematoda and Cestoda in helminths infestated from 218 heads of dairy cattle in Gyongi province. The results are summerizied as follows : Infestation and distribution rate in percent of helminths among the collected fecal samples from dairy cattle are Bunostomum species(spp.) 1.3%, Strongyloides spp. 4.5%, Tricostrongylus spp. 0.8%, Ostertagia spp. 7.3%, Cooperia spp. 4.7%, Nematodrius spp. 1.6%, Haemonchus spp. 5.7% and Oesphagostumum spp. 6.5% in Nematoda, and that of Eurytrema app. 2.1%, Fascioloa spp. 11.8% and Pharamphistomum spp. 51.3% in Trematoda, and that of Moniezia spp. in Cestoda, respectively. After administration for three kinds of anthelminthics infestated dairy cattle, high level of efficacy were confirmed against Nematodes and Cestodes. The average values tend to be incresed amount of milk production and its fat levels after anthelmintics administration on helminths infestated dairy cattle were 1.8 kg and 0.14 % per daily, respectively (p<0.01). Key word : Infestation of helminths in dairy cattle, Effects of milk products.

거대 긴장성 낭종으로 내원한 폐 Langerhans 세포 조직주증

양석철,손장원,윤호주,신동호,박성수,함시영,장세진,박용욱 한양대학교 의과대학 2000 한양의대 학술지 Vol.20 No.1

Pulmonary Langerhans cell histiocytosis is a hetergenous group of conditions of unknown etiology characterized by an abnormal proliferation of antigen presenting cell of bone marrow derivation known as Langerhans cells that invade and destroy distal bronchioles. The outcome is highly variable, ranging from rapid spontaneous resolution to irreversible respiratory failure. We describe a patient with biopsy-confirmed pulmonary Langerhans cell histiocytosis who presented with large tension cyst, treated with pneumothorax tube with Heimlich flutter valve.