SS400강 용접부의 파괴인성치에 관한 연구

국정한,송일규,김봉중,오세용,성호현 한국기술교육대학교 1999 論文集 Vol.6 No.1

In this work, we studied the mechanical properties, structure and the stress intensity factor of the welded areas which were annealed from 500。C to 900。C with an interval of 100。C. The main results are as follow. 1. The as-welded specimen showed the highest tensile strength and yield point. The tensile strength and the yield point decrease as the annealing temperature increased from 500。C to 900。C, and they became smaller in the order of deposited metal, heat affected zone and base metal. 2. The hardness was maximum at about 9 mm from the welding center line, and it decreased drastically in the heat affected zone located between 9∼15mm from the center line. 3. The elongation decreased in the order of base metal, the fusion zone and heat affected zone while it increased as annealing temperature increased. 4. The stress intensity factor(S. I. F.) declined as the length of notch increased and it became smaller in the order of fusion zone, base metal and heat affected zone. This is because fracture toughness is affected by brittlization at heat affected zone as well as the initiation and propagation of cracks.

평균 배기 압력 구배 지수를 이용한 실화 검출 방법

심국상,최민호,김세웅 金烏工科大學校 2000 論文集 Vol.21 No.-

This paper proposes a method to detect the misfired cylinder using a new misfire detection index. The new method of misfired cylinder is a comparison of pressure gradient during the blowdown period of exhaust stroke. If a misfire occurs, the engine will be lost some power and consumes the more fuel and the torque will be unsteady. Most of all, the misfire affects a bad influence of the 3-way catalyst and emits unburned hydrocarbon in the air. To prevent these unusual phenomena and eliminate the factor of the environmental pollution, it is important to detect the misfired cylinder. To do the experiment, set up the assist device on the conventional exhaust manifold. This assist device is not deformed for conventional exhaust manifold and installed in the end of the exhaust manifold. Experimental results showed that the method using the mean gradient pressure index is proven to be effective in the detection of misfired cylinder on gasoline engine regardless loads and revolutions of the engine

응급센터에서 기관내 삽관을 시행하지 않은 호흡곤란 환자의 동맥혈 이산화탄소분압과 호기말 이산화탄소분압의 연관성분석

김형국,박승현,오동렬,박규남,이원재,황두영,최승필,이운정,정시경,김세경 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.4

Background: The end-tidal carbon dioxide tension(ETCO₂) is defined as a partial pressure of carbon dioxide at the end of an exhaled breath. The purpose of this study is to determine the correlation between ETCO₂and arterial carbon dioxide tension(PaO₂) in nonintubated patients with respiratory distress in emergency department(ED). Methods: A prospective non-blind study was performed in ED of our university hospitals. Participants included all nonintubated adult patients with respiratory distress requiring arterial blood gas analysis. ETCO₂was measured with a capnography monitor during tidal volume breathing. ETCO₂were recoreded at the time of arterial blood gas sampling. The correlation between ETCO₂and PaCO₂was analyzed in all patients and in subgroups by simple linear regression. Results: Sixty patients were enrolled. In all patients, ETCO₂was 5.72mmHg lower than PaCO₂and correlated well with PaCO₂(r²=0.716). ETCO₂correlated best with PaCO₂in patients who were either acidotic or non-smoking. Conclusion: ETCO₂correlate well with PaCO₂in nonintubated patients with respiratory distress in ED. ETCO₂may be sufficient to reflect PaCO₂in selected patients and obviate the need for repeat arterial blood gas determination.

공기 보조 분사 장치를 이용한 엔진 성능 향상 및 연비 개선

김세웅,심국상,이근봉 金烏工科大學校 1995 論文集 Vol.16 No.-

This paper describes the improvement of engine performence and fuel consumption through improved combustion formed by the tumble and swirl flows of an in-cylinder fuel-air mixture that uses an air forced fuel injector(AFI) which used compressed air. The AFI is designed to promote fuel atomization and to form uniform fuel-air mixture. In order to make up the tumble and the swirl flows of the in-cylinder mixture, the end of AFI is attached to the tube containing the fuel-air mixture to ensure the adequate flow and to ensure that the remaining kinds of mixture will flow effectively. In order to investigate the improvement of engine performence and fuel consumption, 2 models of tubes which make tumble and swirl flows were utilized. Each model was examined according to engine speed, intake manifold pressure and excess air ratio and compared with a base engine. Compared with the base engine, the results show that the AFI improves the engine performance and the brake specific fuel consumption(BSFC) in all of the engine speeds and the boost pressures at the tumble and the swirlflows. It also decreases exhaust emission of hydrocarbon(HC)

참치 뼈를 이용한 Hydroxyapatite 세라믹 복합체의 합성 및 생체 친화성(제3보) : 인공체액에서의 Hydroxyapatite 세라믹 복합체간의 결합의 전자현미경 관찰 SEM Photographs of Bonding Properties between Hydroxyapatite Ceramics Composites in the Simulated Body Fluid

김세권,최진삼,이창국,변희국,전유진,이응호,박인용 대전산업대학교 반도체기술연구소 1999 半導體技術硏究所報 Vol.1 No.-

참치 뼈에서 추출한 hydroxyapatite를 출발물질로 여러 가지 세라믹 복합체를 제조하여 인공체액에서의 hydroxyapatite 복합체간의 화학결합을 조사하였다. hydroxyapatite 복합체들은 인공체액에서 4주 후부터 화학 결합성질을 나타내었다. 결합강도는 bioglass가 가장 강하게 나타났으며, 조성에 따른 의존성은 관찰할 수 없었다. 인공체액에서 복합체들은 이들의 경계면에서 불균일 핵생성 및 성장에 의해 화학적 결합으로 이루어졌다. Chemical bonding was investigated in the simulated body fluid of several selected hydroxyapatite-containing composites. The hydroxyapatite-containing composites chemically bonded with each other in the simulated body fluid after 4 weeks. Bioglass was strongly bonded in the simulated body fluid, but bonding strength was not depended on composition. Their composite bodies were chemically bonded by heterogeneous nucleation and growth at the interfaces of the specimens in the simulated body fluid.

배기 다기관 형상 변경에 따른 배기계에서의 배기 압력 특성에 관한 연구

심국상,최민호,김세웅 금오공과대학교 산업기술개발연구원 2000 産業技術開發硏究 Vol.16 No.-

Exhaust pressure characteristics was described by change of exhaust manifold configurations in the exhaust system. Exhaust manifolds for analysis of exhaust pressure characteristics in this experiments were made and were single, double and conventional type of manifold. The pressure characteristics in the exhaust system were compared and analyzed according to exhaust manifold configurations, measuring positions, engine revolutions and loads. The results show that the peak pressure in exhaust system was decreased as the number of accessories in the exhaust manifold increased and the measuring position of sensor estranged from exhaust valve. And the accumulation of exhaust gas occurred in exhaust manifold was decreased by formulation of pulsating pressure wave than formulation of high pressure wave.

에스트로젠과 프로게스테론이 골모세포의 증식과 활성에 미치는 영향

하국봉,손우성,김세원 대한치과교정학회 2001 대한치과교정학회지 Vol.31 No.2

치아이동에 대한 생력학적 반응은 골 형성과 재형성의 조합이라 할 수 있다. 골 형성과 흡수에는 국소적으로 작용하는 여러 부분비 인자가 관여한다. 대표적인 여성호르몬인 에스트로젠파 프로게스테론도 그 중의 한 인자로 성인 여성은 생리, 임신, 폐경 등 상태에 따라 체내 성호르몬 농도가 달라진다. 따라서 이러한 농도의 변화에 따라 골조직이 영향을 받을 수 있을 것으로 추정된다. 골모세포는 골흡수를 일으키는 호르몬인 PTH, Vit D3 등에 일차적으로 반응함으로 써 골형성 뿐만 아니라 골흡수에도 일정한 역할을 하고 있어 파골 세포에 영향을 주는 부분비 인자도 추측해 볼 수 있다. 본 연구에서는 ROS17/2.8및 HOS세포주를 배양하면서 에스트로젠 및 프로게스테론 등 여성 호르몬을 처리한 후 골모세포의 증식과 활성에 미치는 영향을 측정하여 다음과 같은 결과를 얻었다. 1.에스트로젠은 HOS 세포의 증식을 억제하였으며 ROS17/2.8 세포의 증식은 촉진하는 것으로 관찰되었다. 2.에스트로젠은 HOS 세포의 alkaline phosphatase 활성을 증가시켰고 ROS 세포에서는 효소활성을 억제하는 것으로 나타났다. 3.프로게스테론은 HOS 및 ROS17/2.8세포 모두의 증식을 억제하였으며 골모세포의 alkaline Phosphatase활성에는 영향을 미치지 못하였다. 4.에스트로젠과 프로게스테론은 골모세포내에서 생성되는 superoxide, nitric oxide 및 gelatinase 활성 등 골모세포의 기능에는 유의한 변화를 일으키지 않았다. Biomechanical reactions of tooth movement are the combination of bone formation and resorption, in which many paracrine factors are involved. The sex hormone is one of the paracrine factors and the sex hormonal level of an adult female varies according to the body condition, e.g. mensturation, pregnancy, Postmenopause, etc. Although the exact mechanism is not clarified yet, estrogen and progesterone are known to regulate the function of osteoblast. Again osteoblast is reported to affect the function of osteoclast. The purpose of this study is to determine the influence of the female sex hormone, estrogen and proresterone, on the cell proliferation and activity of HOS and ROS17/2.8 cell line. The observed results were as follows. 1.Estrogen inhibited HOS cell proliferation and promoted ROS17/2.8 cell proliferation. 2.Estrogen increased the activity of alkaline phosphatase of HOS cell and reduced the activity of alkaline phosphatase of ROS17/2.8 cell. 3.Progesterone inhibited the proliferation of HOS and ROS17/2.8 cell, but had no influence on the activity of alkaline phosphatase. 4.Estrogen and progeterone did not have any particular effects on the activity of super oxide, nitric oxide and gelatinase of HOS and ROS17/2.8 cell.

異常血色素 非α-chain의 分離方法에 관한 硏究

全國奉,金昌世 순천향대학교 1992 논문집 Vol.15 No.2

A non-α-chain anomaly of human hemoglobin, propositus Park, was found at the Chunan Soonchunhyang university Hospital. Propositus Park was a healthy person without clinical symptom because he selected as a blood donor and has a normal laboratory data. The non-α-chain anomaly was confirmed by both starch gel electrophoresis and 8M urea polyacetate membrame electrophoresis. To obtain a large quantity of abnormal hemoglobin We have tried with both a column electrofocusing and a Pevikon block electrophoresis. In the separation of abnormal hemoglobin Pevikon block electrophoresis was a good tools rather than a column electrofocusing. And so We have obtained a large quantity of abnormal hemoglobin, non-α-chain, by means of Pevikon block electrophoresis.

가솔린 기관의 배기계 압력 특성 분석

김세웅,복중혁,심국상 金烏工科大學校 1997 論文集 Vol.18 No.-

This paper describes the characteristics of pressure in the exhaust system. Exhaust system of gasoline engine consists of an exhaust manifold, a primary and a secondary muffler and a 3-way catalyst. And these compositions are tested in the before and behind of each composition. The pressure waves of burnt gas generated in the 4 stroke and 4 cylinder engine are formatted tatal eight pressure waves during the one cycle. The first pressure wave is generated by blowdown and the second pressure wave is generated by burnt gas and velocity of ascending piston. These pressure waves depend on pressure of burnt gas and the second pressure wave is bigger than the first pressure wave as the increased of load. If pressure waves in the exhaust system are analyzed, the cylinder of normal or abnormal combustion is classified and the misfire cylinder could be detected.

복합 산화법과 MEMS 기술을 이용한 RF용 두꺼운 산화막 에어 브리지 및 공면 전송선의 제조

김국진,박정용,이동인,이봉희,배영호,이종현,박세일 한국센서학회 2002 센서학회지 Vol.11 No.3

본 논문에서는 양극반응과 복합 산화법( H_2O/O_2 분위기에서 500℃, 1시간 열산화와 1050℃, 2분간 RTO(Rapid Thermal Oxidation) 공정)을 이용한 두꺼운 OPSL(Oxidized Porous Silicon Layer)을 형성하여 이를 마이크로머시닝 기술을 이용함으로써 10 ㎛두께의 OPS(Oxidized Porous Silicon) 에어 브리지를 제조하고, 그 위에 전송선로를 형성하여 그 RF 특성을 조사하였다. OPS 에어 브리지 위에 형성된 CPW(Coplanar Waveguide)의 손실이 OPSL 위에 형성된 전송선의 삽입손실보다 약 2 dB 정도 적은 것을 보여주었으며, 반사손실은 OPSL 위에 형성된 전송선의 반사손실보다 적으며 약 -20 dB를 넘지 않고 있다. 본 연구에서 개발한 산화된 다공질실리콘 멤브레인 및 에어 브리지 구조는 CMOS 공정 후에 사용 가능하며, 초고주파 회로 설계시 편리성과 유용성을 제시하고 있다. This paper proposes a 10 ㎛ thick oxide air-bridge structure which can be used as a substrate for RF circuits. The structure was fabricated by anodic reaction, complex oxidation and micromachining technology using TMAH etching. High quality films were obtained by combining low temperature thermal oxidation (500 ℃,1 hr at H_2O/O_2) and rapid thermal oxidation (RTO) process (1050 ℃, 2min). This structure is mechanically stable because of thick oxide layer up to 10 ㎛ and is expected to solve the problem of high dielectric loss of silicon substrate in RF region. The properties of the transmission line formed on the oxidized porous silicon (OPS) air-bridge were investigated and compared with those of the transmission line formed on the OPS layers. The insertion loss of coplanar waveguide (CPW) on OPS air-bridge was (about 2 dB) lower than that of CPW on OPS layers. Also, the return loss of CPW on OPS air-bridge was less than about - 20 dB at measured frequency region for 2.2 mm. Therefore, this technology is very promising for extending the use of CMOS circuitry to higher RF frequencies.