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.

중추신경계 손상 환자의 우울과 삶의 질에 대한 음악요법의 효과

최성복,정호중,심영주 고신대학교 의과대학 2010 고신대학교 의과대학 학술지 Vol.25 No.1

Objectives: To identify whether music therapy is effective for depression and quality of life (QOL) of patients with central nervous system (CNS) injury, using controlled comparison method. Methods: Twenty nine subjects with CNS injury assigned to one of the two groups, music therapy group (therapy group) or control group. Music therapy was applied to fifteen patients in the therapy group twice a week for 5 weeks (10 sessions) with daily physical and occupational therapy, while only physical and occupational therapy were applied to the control group routinely. Depression of all subjects was assessed by Beck depression inventory (BDI) and Hamiltonrating scale for depression (HRSD). QOL was measured with the use of the world health organization quality of life assessment instrument-brief (WHOQOL-BREF). Each evaluation was assessed at the beginning of this study and after 10 sessions’music therapy. Results: The mean BDI scores reduced in the two groups, but the differences were not significant. In the therapy group, the mean score of HRSD was reduced significantly after song psychotherapy for 5 weeks, from 7.6±5.6 to 3.5±4.1 (p<0.05), while it was not significantly reduced in the control group. The mean scores of WHOQOL-BREF in the therapy group were advanced in every domain. In the control group the mean score of social relationships domain was worsen after 5 weeks comparing the mean score at the beginning of this study. Conclusions : The music therapy relieves patients with CNS injury from depression, and it also seems to be able to improve QOL of them.

뇌졸중 환자에서 연하장애와 신체기능장애의 연관성

김도성,심영주,김기찬,정호중 고신대학교 의과대학 2010 고신대학교 의과대학 학술지 Vol.25 No.2

Backgrounds : In almost stroke patients, dysphagia is improved with rehabilitation therapy. But, it is not identified the relationship between dysphagia and physical function recovery in stroke patients. Methods : A total of 21 patients with stroke-caused swallowing disorders based on a videofluoroscopic swallowing study (VFSS) were examined swallowing function and physical function at admission and after treatment for 4 weeks (including Vitalstim). Swallowing function was evaluated by the functional dysphagia scale (FDS) using VFSS before treatment and after treatment. Physical function was evaluated by the motricity index (MI) and modified barthel index (MBI) at admission and after 4 weeks. And the relationship between dysphagia and physical function recovery was evaluated. Results : After treatment for 4 weeks, total score, residue in oral cavity, oral transit time, laryngeal elevation and epiglottic closure, residue in valleculae, residue in piriform sinus, coating of pharyngeal wall after swallow were significantly decreased in FDS (p<0.05). There were a significant improvement in MBI (p<0.05) and the correlation between FDS and MBI. But, MI was not showed correlation with FDS. Conclusions : There was relationships between swallowing function improvement and recovery of physical function in almost FDS factors.

심첨부 비후 심근증에서 심근 내 미세 관상동맥의 혈류 예비력 평가 : 경흉부 도플러 심초음파를 이용한 연구 Study Using Transthoracic Doppler Echocardiography

윤호중,박철수,신재원,임상현,조은주,정해억,전희경,오용석,정욱성,김재형,최규보,홍순조 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.3

油菜의 雄性不稔系統에 關한 發生學的 硏究

李萬相,李重浩 圓光大學校 1981 論文集 Vol.15 No.1

油菜의 雄性不稔系統인 Mokpo MS, Chisa MS와 正常品種인 龍塘을 比較品種으로 하여 雄性不稔發現에 있어 그 原因올 밝히기 爲하여 發生學的으로 調査하였던 바, Chisya MS는 不完全하고, Mokpo MS는 小胞子母細胞減數分裂異常으로 四分子期 以後 退化되기 시작하여 開花直前에는 小胞子나 花紛粒은 찾아 볼 수 없고, 絨毯組織, 內被, 中層, 表皮가 그대로 殘存하고 있는 點으로 보아 完全한 雄性不稔系統임이 確實하다. 大胞子에서 Chisaya MS는 正常的으로 卵裝置가 形成되나, Mokpo MS는 異常이 있다. Present work was carried out to investigate the cause of male sterile appearance in the rape with Mokpo MS line and Chisaya MS one as the male sterile lines and with cv Yongdang as nomal variety. The results obtained were as follows: The male sterility of Chisaya MS line was imperfect, but that of Mokpo MS line was perfect on account of abnormal meiotic division of microspore mother cells or being lacking pollen grains at just before blooming and judging from intact remain of tapetal tissue, endothicium, middle layer and epidermis of anther at just before blooming. The egg apparatus of Chisaya MS line was normal, but that of Mokpo MS line, abnormal.

채터 주파수-회전 속도 선도를 이용한 채터 발생 진단에 관한 연구

이상호,박중윤,홍성욱 금오공과대학교 산업기술개발연구원 2000 産業技術開發硏究 Vol.16 No.-

This paper presents a method to identify the on-set of chatter by using the chatter frequency-spindle speed diagram for a milling spindle-workpiece system in face milling process. To this purpose, a new method using frequency response function is adopted for predicting both the chatter condition and chatter frequency. A chatter frequency-spindle speed diagram for various conditions is proposed and studied to diagnose the chatter. The experimental results show that the chatter frequency-spindle speed diagram is useful for diagnosis of the on-set of chatter vibration.

Vinblastine이 백서 배양 Type-1 별아교세포에 미치는 세포독성에 관한 연구

하상호,박승택,문연자,김종영,김정중,정연태 圓光大學校 醫科學硏究所 1994 圓光醫科學 Vol.10 No.1-2

It has been reported that vinblastine, anticancer drug, is a neuroteratogen inducing various neural malformations such as microcephaly and neural tube defect(NTD), but the study on the toxicity of neuroglial cells, especially type-1 astrocytes using culture system is not well established. In order to evaluate the cytotoxicity of vinblastine on cultured type-1 astrocytes of neonatal rat brain in vitro. MTT assay and also light and electron microscopic studies were carried out. The results were as follows: 1. MTT_90 and MTT_50 in cultured type-1 astrocytes were 1×10 exp (-1) μM and 1×10 exp (2)μM of vinblastine, respectively. 2. Vinblastine was highly toxic in cultured type-1 astrocytes(MTT_50 ≤ 100 μM). 3. In a light microscopy, cultured type-1 astrocytes showed decrease of cells in number, cytoplasmic perforation, vacuolization and cytoplasmic granulation after cultured type-1 astrocytes were treated with 1×10 exp (2)μM of vinblastine for 24 hours. Cultured type-1 astrocytes damaged by vinblastine showed degenerative changes of cells morphologically. 4. In an electron microscopy, increment of glial fibrillary acidic protein(GFAP), increased free-ribosomes, cisternal dilatation of rough endoplasmic reticulum (rER). few dense bodies and vacuoles were shown in cultured type-1 astrocytes treated with 1×10 exp (2)μM of vinblastine for 24 hours. The results indicate that vinblastine has markedly cytotoxic effect on the type-1 astrocytes of neonatal rat brain in vitro study.

師範大學 科學科 實驗實習敎育의 模型硏究

尹世重,李聖瑞,徐廷穆,崔鎬亨,蘇鮮燮 공주대학교 사범대학 과학교육연구소 1984 과학교육연구 Vol.16 No.1

師範大學의 生物 實驗 敎育의 改善 方向을 강구하기 위하여 전국 15개 師範大學의 生物敎育科에서 敎育하고 있는 실험 실습을 학점을 중심으로 조사하였고 아울러 20개 非師範系 대학의 생물 실험실습 학점도 조사하여 비교하고, 분석 하므로서 다음과 같은 몇 가지 결과를 얻게 되었다. 1) 師範系 生物 敎育科의 전공 학과중 實驗 實習 배정시간 및 학점수를 늘려 나가야 하겠다. 2) 探究學習 지도 能力을 保有할 수 있도록 實驗 實習 指導 改善 方法을 강구해야겠다. 3) 基礎 共通科目은 3과목 모두를 최소한 1학기는 이수토록 해야 하고 반드시 실험 실습을 竝行 하여야 하겠다. A study for the model of the laboratory experiment curriculum in teacher's college seience was done. Because of individual characteristics in each field in department sc-ience education, the model was not necessarily unique. However, the common elements of frame in this model were suggested as follows : 1. The ratio of laboratory experiment's credits and total major credits. 2. The ratio of basic common laboratory experiment's credits (basic physics, basic chemistry, basic biology, and basic earth science) and total laboratory experiment's credits. 3. Credits and course name of laboratory experiments charactoristic for the science education in teacher's college. 4. Suggestion of the experimental guide for an inquiry learning.

우각차단을 동반한 급사증후군 2예

박상선,남기병,최기준,송재관,김재중,박승정,박종훈,김유호 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.5

척추주위근을 침범한 신경통양 근위축증(Neuralgic Amyotrophy) 2례

전포성,정상욱,김기찬,정호중 高神大學 醫學部 1998 高神大學醫學部 論文集 Vol.13 No.1-2