3축 마이크로 공작기계용 자기예압 공기베어링 스테이지의 정, 동적 특성

노승국,Kornel F. Ehmann,Yoon, Hyung-Suk,박종권 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

In this paper, the static and dynamic stiffness of the air bearing stage for micro-micro machine tool are examined experimentally. For stiffness and precision concerns, air bearing stages are adapted for 3-axis micro-milling machine which is size of 200x200 mm². The air bearings in the stage are preloaded by permanent magnets to achieve desired bearing clearance and stiffness for vertical direction. As the stiffness of the air bearing is primary interests, static stiffness test were performed on XY stage in Z direction and Z column in Y direction. Dynamic test were performed on XY stage and Z column, respectively. Both static and dynamic tests were performed in different air pressure conditions. The vertical stiffness of XY stage is about 9N/μm where Y stiffness of Z column is much smaller as 1N/μm because of the large moment generated by Y force on the column.

Clopidogrel에 의해 발생된 전신 염증 반응 증후군 1례

김민환,김종훈,박경일,박혜연,황철웅,김의석,도준형,남궁준,이성윤,이원로 白中央醫療院 2005 仁濟醫學 Vol.26 No.1

Clopidogrel bisulfate, a widely used inhibitor of platelet aggregation, is considered at least as safe as aspirin. We describe a 61 year old male patient who developed a systemic inflammatory response syndrome consisting of high fever, rash, chills, impaired liver function, and mild leukopenia after receiving clopidogrel after coronary angiography and stent implantation. The reaction resolved promptly after withdrawal of the drug, thus making the diagnosis of a clopidogrel induced reaction highly probable.

내구성을 고려한 표면피복재의 성능평가에 관한 실험적 연구

김영덕,조봉석,윤종기,김용로,장종호,김무한 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

It is recognized that reinforcement corrosion is the main distress behind the present concern regarding concrete durability. The basic method to prevent reinforcement corrosion is coating the reinforcement concrete with surface coating materials but evaluating their performance is necessary to the work satisfactory because they have different performance for each other. In this study. to evaluate performance of surface coating materials, we compare their properties in terms of sticking strength and permeability of carbonation, chloride ion and water with actual reinforcement corrosion under environment of complex deterioration. The results showed that an increase in age also decreases Carbonation velocity coefficients, increases Chloride ion diffusion coefficients and increases water absorption coefficients. As well, an increase in age also increases corrosion of reinforcement due to permeability of carbonation and chloride ion. And sticking strength of inorganic coating material is higher than organic coating material.

복합열화환경 하에서의 단면복구재의 철근부식특성 평가에 관한 실험적 연구

김영덕,박종호,조봉석,김용로,권영진,김무한 대한건축학회 2004 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.24 No.1

The duties of the restorative material are to bear up against stress and to protect reinforcement corrosion. So the restorative material are estimated by various kinds of strength, permeability and etc. But to evaluate performance of the restorative material accurately, it is necessary to estimate their reinforcement corrosion directly in environment of combined deterioration. In this study, to evaluate performance of restorative materials, we compare their properties in terms of compressive and bending strength and permeability of water and air with actual reinforcement corrosion like ratio of corrosion area, weight reduction and corrosion velocity of steel bar under environment of complex deterioration. The results showed that strength and permeability of restorative materials are similar but their reinforcement corrosions are very different. And there is a case that strength and permeability of restorative material are better than normal concrete but reinforcement corrosions are worse.

콘크리트의 급속염화물침투시험에 의한 염화물이온 확산계수 평가에 관한 실험적 연구

김갑수,조봉석,장종호,김재환,김용로,김무한 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

Chloride ions are considered to be the major cause of steel corrosion in concrete structures exposed to seashore environments and also permeation of chloride is controlled by chloride diffusion. Therefore, the study on chloride diffusion of concrete have been done so far by many researchers. In this study, several factors such as capacity of voltage, time of an electric current, concentration of NaCl solution, water-cement ratio, and temperature of the solution were examined to grasp what influence they were on the chloride ion diffusion properties using the Rapid Chloride Penetration Test(RCPT) by electrophoresis. Also standing on the basis of the such result application possibility of Rapid Chloride Penetration Test(RCPT) used in this study will be evaluated and the basic data on the durability design for the chloride attack will be suggested.

축구선수의 Detraining과 Retraining이 혈청지질 및 호르몬농도에 미치는 영향

정정화,박재현,채종훈,성혜련,황지인,윤미숙,노금선,윤종관,윤영학,노순덕,정경숙,박일규,김은희,박현태,박상갑 대한스포츠의학회 1999 대한스포츠의학회지 Vol.17 No.1

The purpose of this study was to investigate the effects of detraining and retraining on serum lipid and hormones in soccer players. Subjects were seven male high-school soccer players. V˙O_2max was determined for each subjects by administering a treadmill test(initial speed: 90m/min, grade: 5%, increasing speed per 3 min: 30m/min). Serum lipid(T-C, TG, HDL-C LDL-C) and hormones(epinephrine, norepinephrine, growth hormones, cortisol) were assayed pre and post detraining in 10, 20, 30 days after retraining. The repeated ANOVA was used to determine significant differences. The 0.05 level of significance was as critical level for the study. The results of the study were as follows: 1. V˙O_2max(ml/min) were 3576.3±204.2ml/min pre detraining, 3234.1±198.9 ml/min post detraining. There are significant(p<.05) difference between pre and post detraining. In 10, 20, 30 days after retraining, V˙O_2max(ml/min) were 3601.4±170.9 ml/min. There were significantly(p<.05) increased in retraining periods. 2. V˙O_2max(ml/kg/min) were significantly(p<.05) decreased from 62.3±2.9 ml/kg/min to 55.9±4.7 ml/kg/min in detraining. In 10, 20, 30 days after retraining, V˙O_2max(ml/kg/min) were 62.4±3.4ml/kg/min, 62.7±2.3ml.kg/min, 67.3±7.2ml/kg/min respectively. There were significantly(p<.05) increased in retraining periods. 3. T-C were significantly (p<.05) increased from 166.6±8.5mg/dl to 175.3±10.3 mg/dl in detraining. In 10, 20, 30 days after retraining, T-C were 160.1± 3.2mg/dl, 156.7±3.7mg/dl, 140.3±9.0mg/dl. There were significantly(p<.05) decreased in retraining periods. 4. HDL-C were 61.4±6.6mg/di pre detraining, 5.3±6.6mg/dl post detraining. There are significant(p<.05) difference between pre and post detraining. In 10, 20, 30 days after retraining, HDL-C were 56.9±7.1mg/dl, 56.4±9.2mg/dl, 57.7±9.1mg/dl respectively. There were no significant difference in retraining periods. 5. The hormones(epinephrine. norepinephrine, growth hormone, cortisol) were changed as same patterns. Epinephrine were 26.0±7.0[g/ml pre detraining, 24.6±3.2pg/ml post detraining. In 10, 20, 30 days after retraining, epinephrine were 26.9±5.6pg/ml, 30.6±6.2pg/ml, 29.4±5.6pg/ml respectively. There were no significant difference in retraining periods. In conclusion, HDL-C, epinephrine, norepinephrine, growth hormone and cortisol were decreased, T-C, LDL-C and TG were increased in detraining. But HDL-C, epinephrine, norepinephrine, growth hormone and cortisol were increased, T-C, LDL-C and TG were decreased in retraining.

증점제를 사용한 고유동콘크리트의 기포조직과 내동해성에 관한 실험적 연구

김무한,권영진,강석표,여동구,김용로,장종호 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.1

Recently, lots of studies for high flowing concrete have been suggested under practical use that it is only a way to solve the confronted problem. However, most studies have been concentrated on the manufacture method and properties of fresh concrete, but there is few studies for the durability of hardened concrete, specially for the freezing and thawing. It is generally known that the frost resistance of concrete is much affected by the air content in concrete and by the air void system. The frost resistance is also believed to vary with the strength of concrete. The purpose of this experimental study is to make a comparison between high flowing concrete using viscosity agent and ordinary concrete about the effect of the viscosity agent, air content and curing method on the frost resistance. As the result of tutus study, the frost resistance have not effect the viscosity agent but effect the different of curing methods.

Characteristic analysis and design of a novel lorentz force driving actuator for a molded case circuit breaker

Jong-Suk Ro,Hyeon-Jeong Bak,Hyun-Kyo Jung IET 2015 IET electric power applications Vol.9 No.1

<P>Recently, the demand for a remote controllable actuator for a circuit breaker (CB) has increased because of the trend towards the automation and information technology (IT) of the power system. However, the conventional molded case CB (MCCB) - of which demand is high among CBs - is not only manually controlled, but also liable to breakdown and difficult to find broken components because of the use of the mechanical spring type actuator. To address these problems, a novel Lorentz force driving actuator (LA) is proposed in this research. The LA is suitable for both low- and high-power CBs because of its high power density and the unaffectedness of performance by the stroke. The MCCB equipped with the LA is the first remote controllable low-power CB and low in maintenance cost. The correct and rapid analysis and design method using a two-dimensional magneto-static field analysis and a dynamic analysis is proposed for the small size actuator as LA in this research.</P>

Characteristic Analysis of an Traveling Wave Ultrasonic Motor using a Cylindrical Dynamic Contact Model

Jong-Suk Ro,Kyung-Pyo Yi,Tae-Kyung Chung,Hyun-Kyo Jung 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

The traveling wave ultra-sonic motor (TWUSM) is operated through the frictional force between the rotor and the stator. Hence, the contact mechanism should be analyzed to estimate the motor performance. However, the nonlinearity of the contact mechanism of the TWUSM makes it difficult to propose a proper contact model and a characteristic analysis method. To address these problems, a novel contact model is proposed and be termed the cylindrical dynamic contact model (CDCM) in this research. An estimation method of the motor performance is proposed using the CDCM, an analytical method, and a numerical method. The feasibility and usefulness of the proposed characteristic analysis are verified through experimental data.

Characteristic Analysis of an Traveling Wave Ultrasonic Motor using a Cylindrical Dynamic Contact Model

Ro, Jong-Suk,Yi, Kyung-Pyo,Chung, Tae-Kyung,Jung, Hyun-Kyo The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.6

The traveling wave ultra-sonic motor (TWUSM) is operated through the frictional force between the rotor and the stator. Hence, the contact mechanism should be analyzed to estimate the motor performance. However, the nonlinearity of the contact mechanism of the TWUSM makes it difficult to propose a proper contact model and a characteristic analysis method. To address these problems, a novel contact model is proposed and be termed the cylindrical dynamic contact model (CDCM) in this research. An estimation method of the motor performance is proposed using the CDCM, an analytical method, and a numerical method. The feasibility and usefulness of the proposed characteristic analysis are verified through experimental data.