마이크로 핫플레이트를 갖는 마이크로 가스센서의 열적성능에 관한 연구

주영철,임준형,이주헌,김창교 대한전기학회 2006 전기학회논문지C Vol.55 No.5(C)

- A micro hotplate for micro gas sensor was fabricated by MEMS technology. In order to heat up the gas sensing material to a target temperature, a micro hotplate was built on the gas sensor. The sensing material was deposited on the heater and electrodes, and did not contact with the silicon base to minimize the heat loss to the silicon base. The electric power to heat up the gas sensor was measured. The temperature distribution of micro gas sensor was analyzed by a CFD program. The predicted electric power to heat up the sensing material showed a good agreement with the measured data. The design of micro gas sensor could be modified to increase the temperature uniformity and to decrease the electric power consumption by optimizing the layout of micro hotplate and electrodes.

자동노출제어장치 유·무에 따른 흉부 후·전방향 검사 시 관전압 변화에 따른 선량 및 영상평가

주영철,홍동희 한국방사선학회 2022 한국방사선학회 논문지 Vol.16 No.7

This study was conducted to improve the problems of exposure dose and image reading applied to patients due to the incorrect use of AEC during chest radiography. Images were acquired by dividing the case where AEC was used as the test condition and the case where AEC was not used. As a result of the study, the dose was reduced by 1.17% in 110 kVp without AEC than with AEC, 17.2% decrease at 100 kVp, 30.19% decrease at 90 kVp, and 46.45% decrease at 80 kVp. There was a significant difference in the statistical values ​​according to the tube voltage change in the lung, trachea, and heart SNR average values ​​with AEC and without AEC 110 kVp, but the difference in image quality was insignificant in actual images. When AEC was not applied at the same tube voltage, the dose could be reduced by 17.2% while maintaining the image quality similar to that of with AEC at 100 kVp without AEC. Therefore, rather than relying on AE conditions during chest radiographic examination, it is considered that the conditions should be considered for the examination while lowering the dose by selecting an appropriate tube voltage. 본 연구는 흉부 방사선검사 시 AEC의 잘못된 사용으로 환자에게 가해지는 피폭선량 및 영상판독의 문제점을 개선하고자 연구를 진행하였다. 검사조건으로 AEC를 이용한 경우와 AEC를 사용하지 않은 경우로 구분하여 영상을 획득 하였으며 0.6 mAs를 고정시키고 110, 100, 90, 80 kVp의 조건으로 촬영하였다. 연구 결과 without AEC 110 kVp가 with AEC보다 선량은 1.17% 감소하였고 100 kVp에서는 17.2% 감소, 90 kVp에서는 30.19% 감소, 80 kVp에서는 46.45% 감소하였다. 폐와 기관, 심장에서 SNR의 평균값의 차이는 with AEC와 without AEC 110 kVp에서 관전압 변화에 따른 통계적인 수치에서는 유의한 차이가 있었으나 실제 영상에서 화질의 차이는 미비하였다. 동일한 관전압에서 AEC를 적용하지 않은 경우 특히 without AEC 100 kVp에서는 with AEC와 유사한 화질을 유지하면서 선량을 17.2% 감소시킬 수 있었다. 그러므로 흉부 방사선 검사 시 AEC 조건에 의존하기보다 적절한 관전압 선택으로 선량을 낮추면서 검사하는데 조건을 고려해 보아야 할 것으로 사료된다.

가솔린엔진 배기가스의 HC 저감을 위한 연료분사시스템의 연구

주영철 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.1

Among many components of gasoline vehicle exhaust emission, HC is the most tightly restricted component by the recently developed exhaust emission standards. In this paper, a spark plug with optical fiber for detecting the signal from the diffusion flame are developed to investigate the HC formation mechanism. A high-speed camera system is also used to elucidate the correlation wall film flow and the diffusion flame. Using these methods, the effects of fuel injection systems such as injection direction, spray angle, atomized injector and ambient temperature on HC emission levels are investigated. Consequently, the optimal fuel injection conditions for minimizing the wall film flow and reducing HC emissions are found through this research.

空氣속에서 염화나트륨(NaCl)의 酸化에 依한 鹽素(Cl₂) 發生에 대한 考察

朱永喆 三陟大學校 1995 論文集 Vol.28 No.1

On the process of manufacturing chlorine widely used for industries by melting sodium chrotide and causing air oxidation, which is also easy and low in cost to produce, It will be surveyed: ① the amount of chlorine produced and set up velocity of temperative. ② the amount of chlorine produced and its reaction time on each of the temperature. ③ the amount of chlorine produced according to the speed of air running. ④ the particle size of sodium chloride.

SLS 쾌속조형기를 이용한 인베스트먼트 주조용 패턴의 형상요소변화

주영철 순천향대학교 부설 산업기술연구소 2001 순천향 산업기술연구소논문집 Vol.7 No.2

We fabricated test samples containing various shape elements and surface roughness checking points for the cast master patterns by employing the 3D computer aided design (CAD), selective laser sintering (SLS) rapid prototype (RP) with the DuraForm powders. The alignment angle was varied from 0˚ to 10˚ at a given layer thickness of 0.08 and 0.1 mm, respectively, in RP operation. Dimensions of the shape elements as well as values of surface roughness are characterize by an optical microscope and a contact-scanning profilometer. Surface roughness values of the top and vertical face increased as the alignment angle increased, while the other roughness valuse and shape elements variation were not depending on the alignment angle. The resolution of the shape realization was enhanced as the layer thickness bacame smaller. The increase of surface roughness of RP products made by old power is due to the shape change of powder particle.

技術開發과 勞動生産性 向上方案

주영철 경기대학교경영대학원 1991 最高經營者課程 經營硏究 Vol.2 No.-

Rhodanin에 依한 銀(I)이온 沈澱에 미치는 ??의 影響에 對한 考察

朱永喆 三陟大學校 1998 論文集 Vol.31 No.2

The relationship between easy detection of traces of ?? ion and reaction type and color variation of reaction mixture with ?? was studied in reaction of rhodanin reagent with ?? was studied in reaction of rhodanin reagent with ?? ion.

금속부품 쾌속제작을 위한 SLS RP의 왁스형 개발

주영철,김태완 한국산학기술학회 2003 한국산학기술학회 학술대회 Vol.- No.-

정밀주조에 사용되는 왁스형을 기존의 수작업과 금형을 이용하는 방법으로 제작하지 않고 SLS형 RP로 캐스트폼형을 만들고 여기에 왁스를 함침시켜 왁스형을 제작하는 공정을 제안하였다. 왁스형의 정밀도를 향상시키기 위해 캐스트폼형 예열시간, 왁스 함침시간, 왁스 함침 회수 등 중요한 공정변수를 변화시켜 가며 왁스형을 만들었다. 왁스형의 정밀도를 측정한 결과 예열시간이 적어도 30분 이상일 때 정밀도가 우수한 제품을 얻었으며, 왁스를 두 번이상 함침할 때 정밀도가 우수하였다. 왁스형의 표면거칠기는 예열시간이 늘어날수록 향상된 표면조도를 얻을 수 있었다.

선형가열법으로 접합한 실리콘 웨이퍼의 열적 특성에 관한 연구

주영철 순천향대학교 부설 산업기술연구소 2000 순천향 산업기술연구소논문집 Vol.6 No.1

The thermal characteristics of silicon wafe direct bonded by using Fast Linear Annealing method has been studied. A computer program that uses the finite difference method has been developed to simulate the temperature distribution of the silicon wafe, which is subjected the radiation heat from the halogen lamp. The moving velocity of halogen lamp has less effect on the local peak temperature of the wafer. It affects the total heat which silicon wafer absorbed and the total heat is related the bonding quality of the wafer.

급속가열장치의 천이상태 열해석

주영철,이광현,윤정관 순천향대학교 부설 산업기술연구소 2012 순천향 산업기술연구소논문집 Vol.18 No.2

The rapid thermal processor is a semiconductor manufacturing equipment which heats silicon or glass wafer to high temperature on a time scale of several seconds. The processor is used for a wide variety of applications in semiconductor manufacturing including dopant activation, thermal oxidation, chemical vapor deposition, and solar cell manufacturing. The temperature uniformity of wafer in heating process is very important. This paper analyses the temperature distribution of rapid thermal processor for solar cell manufacturing by using a CFD program, FLUENT. The results show that the temperature of wafer increases rapidly at 15K/s for the first 30 seconds and then increases slowly. The temperature at the boundary of wafer is lower than that of center. The temperature difference between upper surface and lower surface is 50K. Considering the thickness of glass wafer is 1.7mm, the temperature difference may cause thermal shock.