젊은 성인에서 흡연에 의한 상완동맥 내피기능의 부전에 관한 연구

이상철,권영주,방덕원,이선해,이보영,김지욱,김영훈,온영근,현민수,김성구 순천향의학연구소 2002 Journal of Soonchunhyang Medical Science Vol.8 No.1

Background and Objectives : Cigarette smoking is a major factor and the most modifiable risk factor for atherosclerosis. Endothelial dysfunction is an early event in atherosclerosis, before the structural change of the systemic arteries. We hypothesized that endothelial dysfunction might be present in the systemic arteries of young adult smokers and that this might be dose-dependent phenomenon. Therefore, we try to certify that smoking is associated with endothelial dysfunction in healthy young adults without other risk factor of atherosclerosis. Subjects and Methods : we studied noninvasively 29 subjects aged 3 to 4 decades without other risk factor of atherosclerosis, they were composed of the two groups, current smokers(n=15) and nonsmokers(n=14). Smoking history varied from 3 to 20 pack years. Using high-resolution ultrasound, vessel diameter and mean flow rate were measured at rest, during reactive hyperemia(with flow-mediated endothelium-dependent dilation), and after sublingual nitroglycerin(NG-induced endothelium-independent vasodilation). Result : Flow mediated endothelium dependent dilation was observed in the control subjects (9.4±3.44%) but was impaired in the smokers(5.8±2.51%)(p=0.004). NG-induced endothelium independent dilation is no difference in all subjects. Conclusion : Cigarette smoking is associated with endothelial dysfunction in healthy young adults.

미세 전기기계 시스템용 알루미늄 박막의 탄성계수 및 항복강도 평가

주영창,손동일,관동일 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.3

Nowadays, the aluminum films have wide application in micromechanical devices such as micro sensors and actuators, so that their mechanical properties come to be very important for reliability evaluation. However, there is no standardized method to evaluate the mechanical properties of material used in MEMS (micraelectromechanical system) device since the measured mechanical properties are influenced by many factors such as surface condition, friction force, etc. Hence, we intended to evaluate the mechanical properties of thin film in our study, which is important in mechanical operation. Because MEMS devices are usually operating in elastic range, the Young's modules and yield strength were evaluated by using microcantilever beam technique. First, Al cantilever beams were fabricated using the silicon bulk micromachining technology to have various film thickness. And then, the load-displacement curve was obtained by nanoindentation method. The linear relation in elastic range was utilized in deriving the Young's modulus of Al film, which gives us reproducible result regardless of film thickness. In high load range, the deviation from the linear relation was detected, so that the yield strength of Al film could be evaluated. It is found that the yield strength increases with decreasing film thickness. By applying the misfit dislocation theory and the Hall-Petch relation, the theoretical estimation could predict well the trend of yield strength.

만선신부전 환자에서 관상동맥조영술 소견에 관한 연구

한대희,김성구,박상호,김성한,조원영,방덕원,조윤행,정의룡,은영근,권영구 순천향의학연구소 2003 Journal of Soonchunhyang Medical Science Vol.9 No.1

Background : Patients with chronic renal fialure have a substantially elevated risk of death from cardiovascular diseases than do the general population. the patients with chronic renal failure are at significantly increased freqeuncy of hypertension, hyperlipidemia, and diabetes mellitus which are known to the risk factors of the coronary artery diseases, and the prevalence of the coronary artery diseases in chronic renal failure patients is highly associated with the hemodynamic disorder and metabolic abnormalities. therefore we expected that the coronary angiographic findings in patients with chronic renal failure should be different from the general population (control groups) and investigated the risk factors contributing to coronary artery diseases. Method : we have retrospectively compared the coronary angiographic findings of 44 patients with chronic renal failure on hemodialysis with that of 88 patients in the general population and investigated the factors contributing to the development and acceleration of coronary artery diseases in patients with chronic renal failure Result : Hypertension and diabetes mellitus which is risk factors for coronary artery disease is significantly increased in patients with chronic renal failure, in coronary angiographic finding the severity of the lesion is worse. the incidence of PCI or CABG of patients with chronic renal failure is more than that of control group but statistically no difference between patients with chronic renal failure and control group. the sex, the duration of disease, the duration of dialysis, serum creatinine in patients with chronic renal failure have no correlation to the prevalence of coronary artery disease and severity of lesion. hyperglycemic patients with chronic renal failure have high incidence of coronary artery disease and are worse in the severity of lesion Conclusions : There is significantly increased the pevalence and severity of involving multiple coronary artery diseses in hyperglycemic patients with CRF.

RecurDyn을 이용한 Mold Ejector Sleeve Pin의 와이어 컷 방전가공 메카니즘 시뮬레이션

權寧住 弘益大學校 産業技術硏究所 2007 産業技術 Vol.17 No.-

This paper presents a computer aided simulation of the wire-cut EDM machining of the mold ejector sleeve pin which is used in the ejecting system of the die casting work. For this the ejecting system in the die casting work is studied. Also the principles and characteristics of the wire-cut EDM are studied in detail. The computer simulation is carried using the CAE tool, RecurDyn. The simulation result shows that the contact force between the wire of the wire-cut EDM machine and the inner surface of the mold ejector sleeve pin is very small.

3차원 금형절삭에 있어서 上下方向 切削特性 硏究

권영균,이동주 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.2

In our study, the experiment tried to find the optimum cutting conditions and method by observing the cutting force working at ball end-mill varying axial depth and radial depth for upward cutting and downward cutting along the decline. As a result of the experiment, the cutting was more unstable in downward cutting than in upward cutting and also in the case of axial depth than in radial depth, which resulted from the fact that the cases of downward cutting and of radial depth had a relatively wider contact surface than that of upward cutting and of axial depth and approached the edge at extreme point of a tool more closely rather than a side blade, and the cutting force had a tendency to be reduced as the inclined angle increased.

Random SVPWM 기법을 이용한 고조파 저감에 관한 연구

權炳徽,元鎭熙,宋榮柱 홍익대학교 산업기술연구소 2002 産業技術 Vol.12 No.-

Typical PWM switching method for a induction motor speed control system causes harmonic currents. Induction motor with the rated current by a space vector or a randomly generated fractional number method has been studied for reducing harmonic currents. This paper presents the fixed switching SVPWM and random SVPWM using Matlab / Simulink and then applies to the induction motor operating system, and proposes through simulations for the speed, the response of torque, the waveform of phase current etc. Consequently, the simulation confirms the output current harmonic cancellation by SVPWM inverter.

급성 심근경색증 및 정상적인 관상동맥 조영술을 보인 유전성 S 단백 결핍증 1례

권영주 순천향의학연구소 2004 Journal of Soonchunhyang Medical Science Vol.10 No.2

Protein S is a vitamin K-dependent plasma protein that inhibits the process of blood coagulation via activation of protein C, another vitamin K-dependent plasma protein. Protein S deficiency may be associated with thrombotic events, including venous and arterial thrombosis. We report a case of acute myocardial infarction and normal coronary angiogram with hereditary protein S deficiency.

朝鮮 民畵의 美的 特質

권영주 국제문화학회 2005 Vol. No.

고준위폐기물 처분용기에 대한 구조안전성 평가기준 및 평가방법

權寧住 弘益大學校 産業技術硏究所 2004 産業技術 Vol.14 No.-

In this paper, the structural safety evaluation criteria and method for the spent nuclear fuel disposal canister is studied. Since the spent nuclear fuel disposal emits high temperature heats and much radiation, its careful treatment is required. For that, a long term(usually 10,000 years) safe repository for the spent nuclear fuel disposal should be secured. Usually this repository is expected to locate at a depth of 500m underground. The canister construction which is designed for the spent nuclear fuel disposal in a deep repository in the crystalline bedrock is a solid structure with cast iron insert, corrosion resistant overpack and lid and bottom, and entails an evenly distributed load of hydrostatic pressure from underground water and high pressure from swelling of bentonite buffer. Hence, the canister must be designed to withstand these high pressure loads. If many design conditions are not arranged, structural defects which are caused by the hazardous spent nuclear fuel disposal can occur on the canister during storing it. Therefore, various structural analyses must be performed to predict these structural problems. For this, the structural safety evaluation criteria and method for the spent nuclear fuel disposal canister are required.

초고속선의 기계기술 특성

權寧住 홍익대학교 산업기술연구소 1997 産業技術 Vol.7 No.-

In this study, we reviewed the classification of the super-high-speed ship whose speed is larger than 50 knots and analyzed its mechanical engineering technology characterstics. It is concluded through this study that the traditional(mono or twin) hull form ship which is operated by buoyant force, lift force or air pressure has the limit in speed and size respectively to become to become the super-high-speed passenger and container ship. On the other hand, this analysis shows that the hybird hull form ship can be the super-high-speed ship. In this type of super-high-speed ship, there are SWASH ship, HYSWAS, LAHHS, HYACS, and SWAACS etc..