有限要素法에 依한 Notch部의 應力解析

崔國光 慶北工業專門大學 1974 論文集 Vol.11 No.-

The stress concentration factors of U-notched and V-notched plate subjected to tensile force are calculated by finite element method. Photo-elastic experiment are also carried out. The solutions are compared with Neuber's and Inglis and Armbruster's formula. The following properties are investigated; (1) The data of photo-elastic experiment of U-notched plate are 0.5% greater than the calculated data of finite element method. (2) The data of photo-elastic experiment of V-notched plate are 0.4% greater than the calculated data of finite element method. (3) The calculated data of Armbruster's formula are 1.7% greater than those of U-notched plate by finite element method. (4) The calculated data of Inglis formula are 10% greater than those of V-notched plate by finite element method. The data of photo-elastic experiment among three analysis methods agree satisfactorily with the calculated data by finite element method. This paper is shown that analysis of notched plate by finite element method obtain accurate-solution.

유동층을 이용한 탈황제의 마모특성에 관한 연구

오광중,김형국,최은화,조기철 부산대학교 환경문제연구소 1999 環境硏究報 Vol.17 No.1

For the efficient energy use and the protection of environmental pollution, attrition characteristics, depending on the component and the condition of sorbent for the purification of fuel gas, were analyzed by a fluidized-bed tester. Results of these studies can be summarized follows. 1) When Mn-based sorbent(M, MT, MFT) prepared with varying addictives and induration conditions was compared in terms of particle size distribution and AI(Attrition Index), MT and MFT possessing TiO2 and Fe203 had much higher attrition resistance than M. Attrition resistance of M, MT and MFT increased as bentonite contents and induration temperature increased, when bentonite contents induration temperature were changed from 2 to 5% and from 1000 to 1100℃, respectively. Therefore when powdery catalysts are prepared, the attrition rate can be considerably affected by the controls of addictive, binder and induration temperature. 2) Attrition tests using MT1100-5 were performed under the conditions that particle size distribution was uniform and had much more over +270mesh and under -325mesh. AI due to attrition was 8.83, 21.54 and 1.67%, respectively. Thus, initial particle size distribution showed a great influence on both produced fines distribution and attrition loss. Therefore, the size distribution of particles injected initially and the particle size that carried over showed be considered to reduce the loss of particulate materials and the replacement cost due to attrition. 3) An experiment using MT1100-5 sorbent was also carried out to predict AI as a function of time and particle size distribution during 23hr. AI of prepared sorbent was 4.54, 7.73, 9.08, 11.35 and 12.48 after 1.5, 3, 5, 9 and 23hr. respectively. Thus, it was shown that the amount of produced fines during the same time was shorten with the increase of time. The operating condition of dust capturing equipment and the rate of powder exchange needs to be considered because most of the fines due to fluidization of particulate material was generated at initial operation.

첨단 수송장비용 센서 및 응용시스템 개발

朴世光,崔時永,全國鎭,李光萬 경북대학교 센서기술연구소 1997 연차보고서 Vol.1997 No.-

자동차의 안전성 향상과 편리성은 정밀한 기계적 시스템과 첨단 전자 시스템의 조화에 의한 것이다. 현재 자동차의 전자 시스템 중 엔진의 고효율을 위해 엔진유입 공기량, 실린더의 압력, 엔진의 회전수 등을 검출하는 센서부와 사고의 원인인 타이어 펑크를 모니터링하는 시스템이 첨단 수송 장비의 핵심 부품이다. 따라서 이를 개발하기 위해서 1) 자동차용 Air Flow Sensor, 2) 자동차용 엔진 MAP Sensor, 3) 멀터센서 모니터링 시스템, 4) 자동차 실내 환경제어용 센서시스템 개발을 위한 연구를 수행하였다. 자동차용 엔진 공기유량센서를 제작하기 위해서 유한차분법과 SPICE로 시뮬레이션을 수행하고 이 결과로 센서를 설계하였다. 센서의 저항체를 제작하기 위해서 백금박막을 제작하고 각각 조건별로 특성을 조사하여 패터닝이 잘되고 저항값이 크고 온도계수가 큰 조건을 선택하여 센서를 제작하였다. 센서는 lift-off법으로 백금을 패터닝하고 PI-2723을 보호막으로 사용하였다. 구동회로는 정온도형으로 동작하도록 피이드백 회로를 사용하였고, 기준유량계 출력과 일치하도록 피이드백 회로의 출력전압을 증폭하였다. 유체의 온도와 유량을 변화시킬 수 있는 실험장비를 제작하고 기준유량계와 제작한 유량계의 출력을 동시 측정하여 실험결과를 비교하였다. 유량에 대한 실험에서는 증폭한 출력전압은 기준유량계 출력과 거의 일치하였고, 스텝응답과 과도응답에서도 기준유량계 출력과 거의 일치함을 보았다. 자동차용 엔진 MAP Sensor의 연구에서는 SDB 웨이퍼를 이용하여 절대압 압력센서를 제조하였다. 센서의 구조는 두 개의 휫스톤 브릿지 회로와 다이아프램으로 구성되어있다. 두 개의 휫스톤 브릿지중 하나는 다이아프램의 가장자리에 위치하고, 다른 하나는 다이아프램의 가운데 부분에 위치한다. 다이아프램의 공극은 10^-5 Torr의 진공에서 형성시켜 공극안의 공기로 인한 압력센서의 감도에 미치는 온도효과를 줄였다. 이것은 압력센서의 온도보상에 대한 부수적인 방법이다. 본 실험의 주된 온도 보상법은 두 브릿지의 오프셋 전압의 차를 이용한 방법이다. 이 방법을 이용하여 22 ∼ 100℃ 범위에서 온도 영향을 80 %이상 보상할 수가 있었다. 멀티센서 모니터링 시스템 연구에서는 첨단 수송장치용에 적합한 직접 디지털 출력을 갖는 압력 센서와 온도 센서를 멀티 센서에 적합한 형태로 제작하였다. 압력 센서는 PR 희생층과 금속 구조층으로 하는 표면 마이크로머시닝 기술을 이용하여 제작하였으며, 온도 센서는 n-well CMOS 공정을 이용한 substrate PNP BJT 트랜지스터를 이용하여 제작하였다. 이 두 센서를 함께 제작할 수 있는 공정을 개발하였으며 각각소자에 대하여 측정 셋업을 구성하여 측정하였다. 직접 디지털 압력 센서의 출력에 대한 기본적인 동작 특성을 확인하였으며, 제작된 온도 센서의 감도는 1.57 ㎷/℃ 이다. 자동차 실내환경제어용 센서시스템 개발에서는 표준 CMOS 공정기술과 실리콘미세가공기술을 이용하여 자동차 실내환경 제어용 센서시스템을 개발하기 위하여 마이크로 가스유량센서와 습도센서를 설계하고 제조공정을 수행하였다. 가스유량센서의 경우 설계된 칩의 크기는 3 × 3 ㎟이고, 히터 좌우에 6 쌍의 n-poly/p-poly 열전대를 구성하였다. 습도센서의 경우 칩의 크기가 0.8 × 1.2 ㎟이고 단일 n-poly 실리콘히터로만 구성되어 있는 매우 간단한 구조를 하고 있다. 최소의 열용량과 기판 및 페케지를 통한 열손실을 최소화하기 위하여 열적 및 기계적 특성이 우수한 NON 구조의 브릿지형 다이아프램을 실리콘 미세가공 기술을 이용하여 구현하였다. 또한 NON절연막의 열전도특성을 연구하기 위한 측정소자를 설계·제작하고 그 특성을 측정 중에 있다. 마이크로 습도센서의 동작원리를 기술하고 마이크로 열센서를 구동하게 될 구동회로를 설계·검증하고 있으며 CMOS 회로화 하여 센서와 함께 집적된 센서시스템을 구현할 것이다. The improvement of safety and convenience in motor car lies on the harmony of a minute mechanical system and high-tech electric system. Nowadays the core part of the high-tech transport equipment is the system and the sensor part. The system monitors the flat tire that causes accidents and the sensor part detects the air amount of a engine intake, the pressure of the cylinder and the turn number of an engine for high efficiency of engine in car electronic system. In order to develop it, therefore we have studied 1) an air flow sensor for car engine, 2) a pressure sensor for car engine, 3) the system monitoring pressure of car tire. We designed air flow sensor in use of a finite different method and SPICE simulation to make it. In order to make resistors in the sensor, we made platinum thin film and then we tested the characteristics of the thin film in various conditions. So we chose the condition which is patterning better, higher resistor value and higher temperature coefficient. The sensor of platinum thin film was patterned by lift-off method and passivated with PI-2723. We used the feedback circuit to make an operation circuit drive in constant temperature. We amplified the output voltage of the fabricated sensor in accordance with that of a reference flowmeter. We made an equipment to change fluid temperature and flow. We measured the output of the reference flowmeter and the fabricated flow sensor simultaneously, and compared them. In the experiment, the amplified output voltage nearly agree to the output of the reference flowmeter. The absolute pressure sensor using SDB wafer has been fabricated. The structure of the sensor consists of two Wheatstone bridges and a diaphragm. One of the two Wheatstone bridges is located on the edge of diaphragm, and the other is located on the center of diaphragm. The diaphragm cavity is sealed in vacuum(∼10^-5 Torr) to reduce the effect of temperature due to the vapor in the cavity on the sensitivity of pressure sensor. This is the minor method of temperature compensation method. In this experiment the main compensation method is to use the differrence of the two bridge offset voltages. In this method the temperature effect in the range of 22 ℃ ∼ 100 ℃ was compensated over 80 %. We produced a pressure sensor and a temperature sensor, which are suitable for a multi sensor, and have the direct digital output suitable for an advanced transporting equipment. The pressure sensor was fabricated using a surface micromachining technique with a sacrificial PR layer and a structural metal layer. The temperature sensor was fabricated using a substrate PNP BJT made by use of an n-well CMOS process. We developed the process that could produce these two sensors together, organized and estimated the setup about each element. The basic operating characteristics are identified about the direct digital output of the pressure sensor, and the sensitivity of the produced temperature sensor is 1.57㎷/℃ Micro gas-flow sensor and humidity sensor were designed and fabricated using a standard CMOS process technology and silicon micromachining techniques for an Interior Environment of Automotive. The chip size of designed gas-flow sensor is 3 × 3 ㎟ with six pairs of n-poly/p-poly thermocouples around the heater. For the case of the humidity sensor, the size is 0.8 × 1.2 ㎟ with single n-poly silicon heater and simplicity. A bridge type diaphragm of NON structure having an excellent mechanical and thermal properties, was implemented by silicon anisotropic etch. The thermal properties of NON insulator is investigating using by the measurement device that was designed and made specially. The operating principle of micro humidity sensor was described and the driving circuits of the micro thermal sensors were designed and verified. The circuits in CMOS will be integrated into the sensor system with the thermal sensor.

有限要素法에 依한 notch部의 應力解析과 光彈性實驗과의 比較

鄭然輝,崔國光 嶺南大學校 工業技術硏究所 1974 연구보고 Vol.2 No.1

The design of machine elements formed with various notched shapes requires accurate predictable stress value of the notched position, therefore, many investigators have dealt with this subject, but they only reached approximate value In this paper, the stress concentration factors of the U-notched plate and V-notched plate subjected to tensile force was calculated by the photo-elasticity experiment and the finite element method, subsequently with equations by above method and many invesgatied equants were compared. The result was as follows. (1) The values of photo-elasticity experiment of the U-notched plate are greater than the values calculated by the finite element method. by 0.5% (2) The values of photo-elasticity experiment of the V-notched plate are 0.4% greater than the values calculate by the finite element method. by 0.4% (3) Trying to compare the values, we applied Armbruster's equation to the U-notched plate and to the V-notched plate and the values calculated by the finite element method. The values of the both theoritical equations are 1.7%, this is 10% greater than the values by finite element method respectively.

유방암과 관련된 부수종양성 Stiff-Person Syndrome 1예

방현,이상암,최은정,김광국,박성혜 대한신경과학회 1999 대한신경과학회지 Vol.17 No.5

신부전이 동반된 당뇨병 환자에서 발생된 침습성 모균증 : 수술과 Liposomal amphotericin B 및 GM-CSF 병합 요법에 의한 성공적인 치험 1예

이원영,오기원,임국희,장재혁,이동건,최정현,강무일,신완식,차봉연,이광우,손호영,강성구 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.4

저자들은 신부전이 동반된 당뇨병 환자에서 발생된 부비동형 모균증에 대하여 수술과 함께 liposomal amphotericin B 및 GM-CSF의 복합치료를 하여 성공적으로 치료한 1예를 경험하였기에 문헌 고찰과 함께 보고하는 바이다. Mucormycosis (zygomycosis) primarily affects diabetic or immunocompromised patients and typically progresses rapidly, necessitating surgical excision and antifungal therapy with amphotericin B. Large doses of amphotericin B are needed for cure, but it has the risk of causing significant renal toxicity. The recent development of liposomal amphotericin B allows antifungal therapy to be administered with potentially improved efficacy and reduced nephrotoxicity. We have experienced a case of paranasal mucormycosis successfully treated with surgery, liposomal amphotericin B and GM-CSF. A 59-year-old male suffering from diabetes mellitus for 6 years was admitted with pain at left maxillary area. He was diagnosed as mucormycosis after cytologic exam on the necrotic nasal mucosa, which showed typical hyphae. He have had diabetic nephropathy with macroproteinuria and had rapidly rising serum creatinine levels with the amphotericin B treatment: creatinine levels reverted to basal level with the use of liposomal amphotericin B. Despite surgical excision and continued antifungal therapy, his infection was not effectively controlled. Therefore, GM-CSF was administered additionally to improve phagocytic activity of leukocytes. He was finally cured after receiving a combination of aggressive surgery, liposomal amphotericin B and GM-CSF. To our knowledge, this is the first detailed clinical description of the treatment of mucormycosis with liposomal amphotericin B in Korea.

Comparison of a novel bedside portable endoscopy device with nasogastric aspiration for identifying upper gastrointestinal bleeding.

Choi, Jong Hwan,Choi, Jae Hyuk,Lee, Yoo Jin,Lee, Hyung Ki,Choi, Wang Yong,Kim, Eun Soo,Park, Kyung Sik,Cho, Kwang Bum,Jang, Byoung Kuk,Chung, Woo Jin,Hwang, Jae Seok WJG Press 2014 World journal of gastroenterology Vol.20 No.25

<P>To compare outcomes using the novel portable endoscopy with that of nasogastric (NG) aspiration in patients with gastrointestinal bleeding.</P>

고휘도 LED의 해수투과 특성분석

최성국(Sung-Kuk Choi),최재성(Jae-Sung Choi),정광석(Kwang-Seok Jung),장운용(Un-Yong Jang),길경석(Gyung-Suk Kil) 한국마린엔지니어링학회 2009 한국마린엔지니어링학회 학술대회 논문집 Vol.2009 No.-

This paper described the sea-water penetration of high brightness LEDs depending on wavelength to develop a LED-fish attracting lamp. For the analysis, we fabricated a blue and a white 30W LED modules. The modules set under the sea-water, and the light intensity emitted from the module was measured by a spectrometer as a function of distance. Experimental results shows that the penetration rates were almost same in the air, but the blue light of 470nm was the best in the sea-water.

Dry-Air 및 혼합가스의 절연성 평가

최은혁(Eun-Hyeok Choi),최영길(Young-kil Choi),장승호(Seung-Ho Jang),최상태 (Sang-Tae Choi),우성훈(Sung-Hun Woo),김이국(Lee-Kuk Kim),이광식(Kwang-Sik Lee) 대한전기학회 2008 대한전기학회 학술대회 논문집 Vol.2008 No.5

현재 산업사회의 발달과 더불어 신뢰성 높은 양질의 전기에너지와 운전 및 보수의 간편화, 계통운용의 신뢰성의 확보가 요구되고 있다. 또한 SF. 을 대체할 친환경적인 절연매체의 개발이 절실히 요구되고 있다. 이에 본 연구는 모의 GIS내 친환경적인 절연재료인 질소(N₂)와 산소(O₂)의 혼합가스(N₂:O₂=79:21, N₂:O₂=60:40, N₂:O₂=40:60)과 Dry-Air 기본적인 절연 특성을 밝혀, 각종 전력응용 설비의 절연매체로 사용가능함을 구명하고저 한다.

Temporal changes in adult density of Platypus koryoensis (Coleoptera: Platypodidae) within oak forests

Jung-Su Lee,Won-Il Choi,Dae-Sung Won,Jong-Kuk Kim,Kwang-Sik Choi,Sang-Chul Shin 한국응용곤충학회 2008 한국응용곤충학회 학술대회논문집 Vol.2008 No.10

The first occurrence of oak wilt disease(OWD) in Korea was reported in 2004 and a Platypodid beetle, Platypus koryoensis, was known to contribute significantly the occurrence of the disease. To reduce the oak wilt disease, it is necessary to control density of P. koryoensis under injury level. This experiment conducted to clarify the flying period of adult P. koryoensis. Four forests containing dead trees by OWD were selected and the location of the experimental sites were Mt. Surak in Seoul, Goyang-si, Paju-si in Gyeonggi-do, Hongcheon-gun in Gangwon-do. Sticky trap or vertical multi-funnel trap was settled on Quercus mongolica trees located in infested forest. Density of P. koryoensis was survey with one or two week interval from May to October in 2007 and 2008. The number of the beetle collected by the vertical trap and sticky trap was positively correlated (r2=0.69). The optimum flying period of the beetle was ranged from late June to late July with geographical variations.