도금사업장의 작업환경의 유해인자 노출수준에 관한 연구

문덕환,도수영,이채관,황용식,선병관,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : For the purpose of preparing the fundamental data and assessing the status of exposure level of chemical substances and physical agents. Methods and Material : Such as noise, two types of dust, four types of metals, seventeen types of organic solvents, and four types of other materials classified by specific chemical substances in 21 metal product plating factories classified by 28 processes. The author determined exposure level on those hazardous materials from Jan. to Dec. 2001. Results : The results were as follows: 1. The exposure level for noise was exceeded to Threshold Limit Value(TLV) in the process of 6 cases of Machining, 5 and 4 cases of pre and post-buffing, and 6 cases of waterdrop-removing, the mean noise level of all of processes was not exceeded to compliance level. 2. The exposure level for dust was not exceeded to TLV at all. 3. The exposure level for Chromium(Cr) was exceeded to TLV in Chromium plating process, metal exposure level including Zinc(Zn), Manganese(Mn), and Lead(Pb) was not exceeded to TLV. 4. The exposure level of toluene in case of organic solvents was exceeded to TLV in 1 case of finishing/cleaning, coating/developing process, respectively. 5. The exposure level of four types of other materials classified by specific chemical substances were not exceeded to TLV. 6. The exposure level for dust and metal including Zn, Mn, and Pb was decreased in comparison with two results of air monitoring performed. There was no difference of the exposure level for Cr, noise, and four types of other materials classified by specific chemical substances, and the exposure level for organic solvents was slightly increased. 7. The exposure level for noise in factories employing more than 21 workers was higher than that for noise in foadtories employing less than 20 workers. The more workers, the lower exposure level in metal including Zn, Mn. The exposure level for Cr was increasing in factories employing more than 51 workers, and the more workers the lower exposure level in organic solvents. Conclusion : According to above results, this study suggests positive work environment managements in processes exceeding exposure limit value as well as continuously consecutive work environment management in processes not exceeding exposure limit value and revealing no chronological difference of exposure level should be needed.

Hepatic Cirrhosis Occurring in a Young Woodchuck(Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus(WHV)

Kyu-shik Jeong,정원일,Jae-yong Chung,Mi-young An,Chae-yong Jung,Gyoung-jae Lee,Jong-soo Kang,Byeong-cheol Kang,Young-heun Jee,Bruce H Williams,Young-oh Kwon,Da-hee Jeong 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

Cirrhosis Occurring in a Young Woodchuck (Marmota monax) Due to Vertical Transmission of Woodchuck Hepatitis Virus (WHV)Da-hee Jeong, Won-il Jeong, Jae-yong Chung, Mi-young An, Chae-yong Jung, Gyoung-jae Lee1, Jong-soo Kang1, Byeong-cheol Kang2, Young-heun Jee3, Bruce H Williams4, Young-oh Kwon5 and Kyu-shik Jeong*College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Korea1Shinwon Scientific Co., LTD, Research Institute, Suwon, Korea2Clinical Research Institute, Seoul National University, Seoul 110-744, Korea3College of Veterinary Medicine, Jeju National University, Jeju 690-756, Korea

비정질 합금이 나타내는 소성의 원천

이석우,이창면,채수원,김유찬,이재철 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.5

Various Cu-Zr bearing monolithic amorphous alloys, exhibiting different stress-strain behaviors, were prepared to investigate the nature of the plasticity shown by theses alloys. Microscopic observation of the quasi-statically compressed Cu_(50)Zr_(43)A1_(7) specimen revealed abundant precipitation of nanocrystallites, while insignificant changes in the microstructure were observed from the Cu_(64)Zr_(36) alloy. Finite element analysis was conducted in order to better understand the role of nanocrystallites in an amorphous matrix on the plasticity of the amorphous alloy. The activation energies for crystallization of the amorphous alloys were measured and correlated with the plasticity of the amorphous alloys. Herein, we report for the first time that the origin of the plasticity of monolithic amorphous alloys lies in the activation energy for crystallization. (Received February 14, 2005)

자연색 재현을 위한 색역 사상과 디더링

이채수,장주석 경운대학교 산업기술연구소 2001 産業技術硏究論文誌 Vol.3 No.2(C)

Recently many devices print electronic images in a variety of ways. The reproduced color, however, is different from the original color because of the difference of hardware characteristics. To maintain device independent color, gamut mapping method is proposed. The proposed color gamut mapping uses nonlinear intensity mapping and clipping for saturation mapping on HSI color space. In the dithering operation, expanded nonlinear ordered dithering and modified error diffusion are proposed. The proposed ordered dithering uses expanded nonlinear quantization which considers overlapping phenomena of neighbored printing dots. In the modified error diffusion, quantization error to be diffused are adjusted to improve both image blur and color change produced in the error diffusion. So, the printed image is similar to the image of monitor. Our results indicate that proposed algorithm can produce high quality image in the low bit color devices.

항공기 고장진단에 효율적인 병렬 생성 시스템에 관한 연구

이종성,채수환,송동호 한국항공대학교 1996 論文集 Vol.34 No.-

실시간처리 분야의 전문가 시스템에 있어서 빠른 추론을 통해 응답 시간을 줄이는 것이 가장 중요하다. 최근 생성 시스템의 속도 향상을 위해 병렬처리 기술에 대한 연구가 활발하다. 본 연구는 규칙베이스를 이용하여 구성된 고장진단 시스템에 적합한 병렬후향추론과 병렬후향추론을 효율적으로 수행하는 병렬 생성 시스템을 제안하고, 이를 항공기 공장진단문제 영역중 엔진 고장영역에 적용하여 제안된 시스템의 성능을 평가하였다. 제안된 시스템의 성능평가를 위해 이산사건 시뮬레이션을 기반으로 한 DEVS-Scheme을 이용하여 모델링 및 시뮬레이션을 수행하였고, 그 결과 제안된 시스템이 제안된 병렬후향추론을 사용하는 항공기 고장진단 시스템에 효율적임을 입증하였다. It is most important in expert systems applied to real-time application fields is to reduce the response time by using efficient inference. Recently many researches have been studied on parallel processing technologies for improving the speed of production systems. We propose a parallel production system which efficiently operates fault diagnostic systems constructed by rule-base system with backward chaining inference. We evaluate and analyze performance of the proposed parallel production system by applying it to the aircraft engine fault diagnosis of aircraft fault diagnosis as an example. By using DEVS-Scheme we simulate the proposed system and then evaluate its performance. Simulation results show that the proposed parallel production system is efficient for the fault diagnostic systems with backward chaining inference.

마늘의 동결건조 과정중 ALLICIN 성분변화에 관한 연구

이명환,채수규,전문진 고려대학교 자연자원대학 1995 자연자원논집 Vol.35 No.2

AlIium속 식물인 마늘을 생것인 상태 및 이들을 통째로, 얇게 썰어서 또는 다져서 동결건조처리에 따른 allicin을 포함한 유용성분의 함량변화와 allinase의 효소활성을 측정한 결과는 다음과 같다. 1. 시료의 전처리 방법에 따른 allicin과 dially1 disulfide의 함량은 생 것인 상태, 통째로 및 얇게 썰어서 및 다져서 동결건조시킨 순으로 감소하는 경향을 나타내었으며, 다져서 동결건조시킬때 약 35.3%의 allicin감소를 나타내었다. 2. pyruvate 함량을 시료 중량대비로 측정한 결과 생것인 상태보다는 통째로, 얇게 썰어서 및 다져서 동결건조시킨 순으로 증가하는 경향을 나타내었다. 3. 마늘의 동결건조방법에 따른 allinase 활성을 측정한 결과, 생마늘의 allinase 비활성은 7.422units/mg protein이었으며, 통째로, 다져서 및 얇게 썰어서 동결건조시킨 순으로 감소하는 경향을 나타내었다. 4. 동결건조시간 경과에 따라서 마늘을 통째로, 다져서 및 얇게 썰어서 동결건조시킬때, 수분함량이 감소하고, allinase활성은 감소한 반면에 puruvate의 함량은 증가하였으며, thiosulfinate 함량은 시간경과에 따라서 감소하는 경향을 나타내었다. The purpose of this study is to investigate changes in the amount of useful compounds including and in the enzyme activities of alliinase as a result of freeze-drying treatment of garlic in whole, sliced or crushed state. The results obtained are as follows: 1. The amount of allicin and diallyl disulfide was decreased: the degree of decrease was in the order of raw, freeze-dried whole, freeze-dried sliced and freeze-dried crushed. Garlic showed 35.3% allicin decrease almost 100% when they were freeze-dried crushed 2. The amount of pyruvate was increased: the degree of increase was in the same order as above. 3. The activity of allinase was reduced as a result of freeze-drying treatment: the degree of reduction was in the order of whole, crushed and sliced. The activity of allinase in raw garlic was 7.422units/mg protein. 4. When garlic was freeze-dried as whole, crushed or sliced, the amount of water and the activity of allinase decreased while the amount of pyruvate increased as time passed. And the amount of thiosulfinate tends to decrease as time passed.

수입 중국산 개나리 열매(연교)의 소염효과에 관한 연구

이응식,조재민,민윤식 충주대 산업과학기술연구소 1996 産業科學論文集 Vol.4 No.-

In order to determine whether methanol extract of Chinese Forsythiae fructus inhibite acute and chronic inflammatory responses induced with histamine and carrageenin in rat, this research was carried out. Inhibitory effect on the pigment leakage induced with histamine 50㎍ by methanol extract 0.15g per 150g body weight was shown positive result significantly. In the experiment by carrageenin paw edema method, maximum inhibitory effects were shown 1hr and 30min after orally administrated with 0.03g and 0.3g methanol extract per 150g body weight, respectively. In the inhibitory effect by methanol extract on the acute inflammation induced by granuloma pouch method, it was shown that inflammatory exudate of granuloma pouch and wet weight of granulation tissue reduced. In the chronic inflammation by granuloma pouch method, inhibitory effect was observed but significant inhibition was not observed statistically. The results of this research were shown that methanol extract of Chinese Forsythiae fructus has inhibitory effects on the acute and chronic inflammation, and were similar to those reported on Korean Forsythiae fructus.

대기중에서 polymer의 레이저 크레이터링

채희백,이수빈,홍진수,김승우 순천향대학교 기초과학연구소 1997 순천향자연과학연구 논문집 Vol.3 No.2

Nd-Yag pulsed laser(210mJ, 6ns) was focused on polymer to make craters in an atmosphere. The size of the crater has a trend to follow the ideal estimation. Laser-firing near the focal point in air could be an energy dissipation of laser and a possible cause of the crater size reduction. Multiple plasma image and normal eruption of the plasma was also studied with photographs.

인공위성을 이용한 MPEG-4 스트림 전송

이남경,채수환 한국항행학회 2002 韓國航行學會論文誌 Vol.6 No.4

MPEG-4 시스템에서의 객체들은 ES(Elernmentary Stream)로 구성되며 객체기반 코딩을 통하여 각각의 객체들이 독립적으로 운용될 수 있으며 DMIF(Delivery Multimedia Integrnework Framework)를 통해 전송된다. MPEG-4 시스템에서의 데이터 스트림은 DVB-Data Camousel을 이용하여 전송 할 수 있으며, DVB-Data Camousel은 데이터의 반복적인 전송을 통해 서비스의 안정성 및 효율성을 향상시킬수 있다. 본 논문에서는MPEG-4 시스템 객체중 일부 데이터 스트림을 DVB-Data Camousel을 이용하여 인공위성을 통해 플라이언트에게 전달하는 시스템에 대하여 다루었다. 또한 위성을 이용할 경우 발생하는 연등지연시간을 줄이기 위해 성능향상서버 (Performance Enhancing Proxy server)를 사용하였다. In Mpeg-4 system, objects are composed of ES(Elementary Stream). Each of the objects is managed independently by object-based coding and is transmitted via DMIF(Delivery Multimedia Integration Framework). The data streams im Mpeg-4 are transmitted with using DVB-Data Carousel which can improve the reliability and efficiency by cyclic retransmission. This paper describes a system which transmits some part of data stream of Mpeg-4 object with using DVB-Data Carousel to clients via satellite. This also uses a performance enhancing proxy server for reducing round trip time between ground network and satellite.

복합재료 실린더의 크��거동 및 응력이완

채동,이수용 한국항공대학교 2000 論文集 Vol.38 No.-

복합재료 실린더에 대한 크��거동 및 응력이완을 고찰하기 위해서 선형 점탄성 지배방정식을 유도하였다. 라플라스 변환을 이용하여 해석 해를 구하였다. 압력 및 온도하중이 작용할 때 준등방성 복합재료 실린더에 대해 크��거동 및 응력이완을 살펴보았다. 수치예제를 통해서 시간이 변화됨에 따라, 복합재료 실린더의 모든 적층에서 응력 및 변위가 항상 감소되는 것이 아니라 어느 일부 적층에서는 오히려 증가됨을 알 수 있었다. Linearly viscoelastic governing equations are derived to investigate the creep behavior and stress relaxation of a composite cylinder. Analytical solutions are obtained by using the Laplace transform. The creep behavior and stress relaxation for the quasi-isotropic composite cylinder under thermal loading and pressure are studied. Numerical examples show that, as the time changes, the stresses and displacements in all the layers of the composite cylinder are not always decreased but increased in some layers.