니켈기 초내열합금의 고온부식거동에 관한 연구

최승주,이재현,이찬규,김근수,이종훈 國立 昌原大學校 産業技術硏究所 1998 産技硏論文集 Vol.12 No.-

Hot corrosion behavior of the CMSX-2, CMSX-4, Rene 77, Rene 80 Ni-base superalloys was investigated at 900℃ by two different corrosion methods, immersing the samples in Na2SO4-NaCl mixture(immersion test)and coating the salt mixture on the surface of the samples(modified coating test). The effects of corrosion times and salt compositions from 0 to 100 percent in Na2SO4-NaCl mixtures were examined. Experimental results showed that the corrosion depths in the alloys increased with increasing time, and the depths of the modified coating test were shotter than those of the immersion test in the mixed salt. It was found that the depths of CMSX series alloys increasing NaCl contents in the mixtures up to 50% NaCl. Corrosion products of the alloys were composed of Cr, Al, Ti oxides. The oxide scale, such as Cr₂O₃, Al₂O₃, TiO₂, were shown to improve hot corrosion resistance in the fused Na₂SO₄-NaCl mixtures.

체외 충격파 쇄석기에 의해 발생된 음향 흐름 현상 연구

최민주,이승환,홍경진,김호찬,박재우,이헌주 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

Acoustic streaming produced by an extracorporeal shock wave lithotripter was visualized for the first time in the present study. It was observed that the streaming velocity increased with the shock wave amplitude and was reaching up to 3 cm/s at the highest output setting of the lithotripter.

신장에 발생한 섬유육종 1례

이재규,손경민,권동득,오봉렬,류수방,박양일,최찬 大韓泌尿器科學會 2001 Korean Journal of Urology Vol.42 No.7

MACHINING CENTER를 利用한 鏡面加工에서 表面粗度에 관한 硏究

최재용,전언찬 東亞大學校 海洋資源硏究所 1993 硏究論文集 Vol.6 No.1

This study has been performed to experiment of plastic metallic mold KP-4M on the variation of spindle revolution, feedrate, polishing times, grain size, and the pressure adding to tool.The results obtained from this study are as follows : 1. Surface roughness(Ra) grows worse, as the velocity is lower in the area of low revolution, and the velocity highter in the area of high revolution. 2. Above 1500rpm at the spindle revolution, Ra grows worse if polishing times (N) is less than 2 because of the preceding process, and the surface turn brillant if polishing times more than 4 because of loading. 3. As the higher pressure which adding to a tool is better when we expect more manufacturing quantity, and we need low pressure when surface roughness take precedence of quantity. 4. On the basic of the experimental findings, it is possible to be automatic of mirror like finishing with the machining center.

農業機械要素의 스트레인 測定에 關한 基礎的 硏究

崔秉旻,文燦,全炳柱,朴又龍,金在煐 順天大學校 1984 論文集 Vol.3 No.1

This experiment is on a direct measuring system of sensor's transform voltage by using measuring computer which does not use data recorder of oscillo graph. The results obtained from the experiment are as follows: 1. Measuring data can be promptly acquired by A/D converting program and measuring computer program. 2. Separte recording and graphing are needless, for a graph and a data of measuring voltage are directly printed by a printer. 3. Simplification and miniature of measuring can be obtained through on-line measuring system by using measuring computer program. 4. Strain, bending moment, bending stress and load can be gained by using a leanear equation which is gained by relation of voltage versus strain.

冷間押出用 헬리컬기어 金型의 强度解析

崔載燦,權赫洪,辛榮柱 부산대학교 공과대학 1992 工大論文集 Vol.44 No.-

In forging die design, pre-stressing is useful in preventing excessive tensile circumferential stresses which may cause die failure during forming. The finite element analysis (F.E.A.) package ANSYS reversion 4.4 A was used to this study. F.E.A., that is, static analysis was accomplished for insert-dies of helical gear. Die model was constructed with 8 node isoparametric solid finite elements. Static load analysis was performed for internal and outer pressure. Also, stress distribution and deformed shapes are shown. To assure durability and reliability, failure analysis was calculated by maximum normal stress theory and distortion energy theory. Results of the F.E. analysis and failure analysis for Samanta and new process dies were compared. The results of F.E. Analysis were in good agreement with that of experimental results. It is expected that the results of this study can be applied to designing various kinds of extrusion gear die.

골프지도자 서번트 리더십과 신뢰관계

최웅재,박찬희 한국스포츠리서치 2004 한국 스포츠 리서치 Vol.15 No.6

This study aims to examine the relationship beetween golf leaders' servant leadership style and trust. The study used survey research methods to analyze a sample group of students of from the department of golf teaching. Results were analyzed using the SPSS statical sftware program Generally, the main statistics employed were frequency, average and simple correlationship. To analyze the hypothesis, the overall regression F-test, ANOVA and LSD analysis were used. In this contest, the findings are as follow: The regression analysis with regard to golf leaders' leadership style showed that it was highly related to servant "sympathy(r=.262)". The lowest variable presented were sympathy related to servant. Opinion could impact golf leader and player's place or circumstances under trust. Result show that opinions could impact golf leader and player's place or circumstances under trust. Most of players select human network(72.2%), including active communication, building trust, sympathy ,and friendly exchange between alumni.

Hg₁-xMnxTe산화막의 홀효과에 관한 연구

오재근,최기영,송재흥,김영국,채건식,주유환,설정식,손인호,차성극,이상찬 慶南大學校 附設 基礎科學硏究所 1996 硏究論文集 Vol.8 No.-

HClO₄(pH:2) 수용액에서 양극산화 방법으로 HgMnTe(HMT)의 표면에 산화막을 형성 시켰다. 산화막의 두께는 SEM으로 측정하였으며 10㎛였다. 전류-전압 특성곡선을 얻어 산화 피크 전압으로부터 HTeO₂?, TeO?, HHgO₂? 막이 형성되었음을 알 수 있었다. 산화시키지 않은 HMT와 HClO₄수용액에서 산화시킨 HMT에 대해 Hall전압 및 자기저항을 각각 측정하였다. 홀전압과 자기저항은 HMT보다 HMT산화막에서 더 컸으며 이것은 HHgO₂? 공격자가 홀의 역할을 하고, TeO₄? 산화막은 전하의 포획도를 낮게하기 때문으로 생각할 수 있다. Anodic oxidation processes on HgMnTe surface has been studied in standard aqueous HClO₄(pH:2) solution. The 10㎛ thickness of the anodic oxide layers was measured by SEM. The Composition of the anodic oxide layers are evaluated from current-voltage(I-V) characteristic of HgMnTe Oxidation. The layers are composed of mixed oxide. ??, TeO₄, and?? in HClO₄solution. Transport properties have been investigated in HMT oxide layer made in HClO₄solution and virgin HMT samples at 300K. Hall voltage and magnetoresistance are greater in oxide layer HMT than virgin HMT. As a result, we know that the vacancy of ??in an anodic oxide layer acts as hole and the resulting oxide ?? layer exhibit a reduced degree of charge trapping and increase magnetoresistance.

진행성 위암과 동반된 후복막 섬유화증 7예의 임상적 고찰

장재영,천영국,최우봉,김진오,조주영,이준성,이문성,심찬섭 순천향의학연구소;Soonchunhyang Medical Research Institute 2000 Journal of Soonchunhyang Medical Science Vol.6 No.1

Background/Aims: Retroperitoneal fibrosis is a fibrosing disease process which frequently develops ureteral obstruction. Malignant retroperitoneal fibrosis has been reported that various types of cancer including cancer of the breast, stomach, prostate, lung, cervix, uteri, colon, pancreas, ovary, and even Hodgkin's disease. While the pathogenesis remains obscure, small foci of metastatic neoplasm in the retroperitoneal space can elicit a desmoplastic reaction in secondary form to malignancy. Methods: Recently we experienced 7 cases of retroperitoneal fibrosis with advanced gastric cancer. So, we report 7 cases of retroperitoneal fibrosis with clinical and radiologic characteristics. Results: The most common signs and symptoms were related irreversible renal dysfunction. The urologic finding noted medial deviation of the involved ureters and hydronephrosis Conclusions: Clinical manifestations are abdominal pain, back pain, hydronephrosis, and uremia. When sudden back pain and hydronephrosis develop in advanced malignancy, physicians should be considerd for retroperitoneal fibrosis.

통계적 기법을 이용한 마이크로 스피커 다이아프램의 최적형상설계에 관한 연구

안찬우,홍도관,최재기,박진우 東亞大學校附設 生産技術硏究所 2007 生産技術硏究所硏究論文集 Vol.12 No.-

This study uses response surface methodology to explain correlations between the objective function and design variables, fractional factorial design and central composite design were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on fractional factorial design and central composite design are made. Therefore this study carried to decide design variables for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using response surface methodology and screening(fractional factorial design), we showed improved design variables.