커패시터 放電 임펄스 着磁機 및 着磁 요크시스템의 定數算定에 관한 硏究

白壽鉉,金 龍,金必洙,尹秀鳳,朴永浩,尹信容 동국대학교 대학원 1992 大學院硏究論集-東國大學校 大學院 Vol.22 No.-

In a capacitor-discharge impulse magnetizer, a magnet is magnetized by the discharging current of capacitor The actual construction of magnetizing fixtures and discharge matching is expensive and time-consuming. Since the parameters of the impulse magnetizer have been determined and the resistance and inductance of such a magnetizing fixture can be easily computed using FEA, it is possible to predict the performance of such a fixture without actually building it. This paper describes that by mathematically modeling the capacitor-discharge impulse magnetizer fixture the problem can be solved with resonable predictability. The basic equations are presented and used to predict the magnetic-field intensity inside the fixtures. Finite-Element-Analysis is also used as part of the design process

3단 및 변형 2단 카세트 샘플러의 공기중 수산화나트륨 포집효율의 실험적 연구

윤영식,김치년,김현수,노재훈 한국산업위생학회 2002 한국산업보건학회지 Vol.12 No.1

Sodium hydroxide(NaOH) is one of the chemicals produced great quantity in Korea. It variously uses for acid neutralization, petroleum refining, electroplating, metal cleaning, laundering, bleaching, washing dish, manufacture of paper, etc. NaOH is used in various field of industry but information on the sampling efficiency for NaOH IS seldom provided. The objective of this study was to compare the sampling efficiency of the three-piece cassette sampler with the modified two-piece cassette sampler. The three-pieces cassette consisted of an inlet cover, a spacer, a mixed cellulose ester membrane(MCE) filter, a back-up pad and a bottom. The modified two-pieces cassette consisted of the same parts as a three-piece cassette without a spacer. The whole inner surface of the 2-piece cassette was loaded with MCE filter to ensure that all of the aspirated NaOH. The air sampling of airborne NaOH WAS performed according to the Occupational Safety and Health Administration(OSHA) analytical method manual ID-121 that is used for the method of occupational environment measurement and analysis. Air samplings were per-formed by simultaneous samplings using the three-piece and modified two-piece cassette sampler at the same time and same place in the chemical plants. The significant difference between average adsorbed amounts on the MCE filters of the three-piece and modified two-piece cassette sampler was found. Sampling amounts of the modified two-piece cassette sampler was 1.84 times higher than that of the three-piece casstte sampler(p<0.01). An average 47% of NaOH was collected on the upper (inlet+middle-rim) side of the modified two-piece cassette. As the result of his study, it is verified that the modified two-piece cassette sampler is more effective than the three-piece cassette sampler for collection of airborne NaOH.

고효율 DC/DC컨버터 제작을 위한 동기정류기 도전 손실 해석

윤석호,김용,백수현,김필수 동국대학교 산업기술연구원 1999 산업기술논문집 Vol.14 No.-

최근 반도체 소자의 제조기술 발달로 정보통신기기 등에 사용되는 온보드(on-board) 컨버터의 전원전압은 3.3V 또는 1.5V의 저전압 전원이 사용된다. 이러한 저전압 전원방식은 온보드(on-board) 컨버터의 정류기단 전력손실이 증가하게 되어 시스템의 높은 효율을 얻기가 어렵게 된다. 낮은 전원전압 방식일수록 정류기단에서 전력손실은 더욱 증가하여 컨버터의 효율은 낮아진다. 고전력밀도의 정류기단 구성을 위하여 출력단에 다이오드 대신 MOSFET 자기구동 정류기를 사용한다. 그러나 MOSFET 자기구동 정류기의 전력손실은 2차측 구동전압의 형태나 기생인덕턴스의 영향을 받게 된다. 따라서 불연속에서는 기생인덕턴스에 의한 MOSFET와 쇼트키 다이오드의 도통주기의 변화가 MOSFET 자기구동 정류기의 전력손실에 미치는 영향을 분석하였으며, 그 결과 기생인덕턴스의 크기를 감소시켜 MOSFET의 도통주기를 증가시킴으로써 MOSFET 자기구동 정류기의 전력손실을 최소화하였다. Recently, new trend in telecommunication device is to apply low voltage, about 3.3V-1.5V. However, it is undesirable in view of high efficiency and power desity which is the most important requirement in the distributed power system. Rectification loss in the output stage in on-board converter for distributed power system are constrained to obtain high efficience at low output voltage power supplies. This paper is investigated conduction power loss in synchronous rectifier with a parallel connected Schottky Barrier Diode(SBD). Conduction losses are calculated for both MOSFET and SBD respectively. The SBD conduction power loss dissipates more than the MOSFET rectifier conduction power loss.

천연자원을 이용한 간기능 증진제 개발 연구 : Benzo(a) pyrene에 의해 유도된 간기능 장해에 미치는 세신 추출액의 영향 The Effect of Asiasari Radix on Benzo(a)pyrene Induced Hepatotoxicity

윤수홍,박은주,오관현 효성여자대학교 부설 한국환경위생연구소 1994 환경위생연구 Vol.4 No.1

Effect of Asiasari Radix, which is a herbal drug used frequently in the oriental prescriptions, water extract on the liver-protective activities were investigated in the rats. Asiasari Radix extract, when administered into the gast-ric intubation, produced liver-protective effect against benzo(a)pyrene induced liver damage. The results obtainedfrom liver microsomal enzyme assay, measurement of serm and liver alanine·aspartate aminotransferase and lipid accumulation, indicated that alismatis extract showed significant liver-protective activities agai-nst benzo(a) pyrene poisoning.

천연자원을 이용한 간기능 증진제 개발 연구 : Benzo(a)pyrene에 의해 유도된 간기능 장해에 미치는 천궁 추출액의 영향 The Effect of cnidii Rhizoma on Benzo(a)pyrene Induced Hepatotoxicity

윤수홍,이송애,하헌,박은주,오관현 효성여자대학교 부설 한국환경위생연구소 1993 환경위생연구 Vol.3 No.1

민간에서 주로 사용되는 약용식물들 중 간독성 의 발현 저해 및 간기능 보호 효과가 우수한약물을 찾아 임상적인 약효를 밝혀보고자 하는 실험과정으로 탄소화합물의 불완전 연소및 열분해에 의해 생성되는 간장해 물질인 benzo(a)pyrene으로 유도한 rats의 간독성발현에 미치는 천궁 수침액의 예방 및 치료 효과를 실험하여 다음과 같은 결과를 얻었다. 1. 천궁 수침액의 투여는 B(a)P 투여로 현저하게 증가된 혈청 및 간장의 AST, ALT,LDH, ALP 활성을 유의성 있게 감소시켰다. 2. B(a)P 투여로 증가한 혈청 total cholesterol 및 phospholipid 함량은 천궁 수침액의투여로 감소시킬 수 있었으나 그 효과는 현저하지 않았다. 3. 천궁의 투여는 B(a)P에 의한 간독성 발현을 유의성 있게 감소시켰으며 그 효과는전처리가 후처리에 비해 우수하였다. The present study was undertaken to compare the pharmacologicalactivity of crude Cnidii Rhizoma reported with the clinical uses in the orientalmedicine. Crude Cnidii Rhizoma used for the treatment of anemia, body chill,menstural irregularity and menstural pain as hematic, tonic effector, sedative,adodyne and clear extravasated blood. Therefore we tested the effects of Cnidii Rhizoma water extract on the liver-protective activities in the rats. The results obtained from liver microsomal enz-yme assay, measurement of serum and liver alanine, aspartate aminotransferaseand lipid accumulation indicated that Cnidii Rhizoma extract showed significantliver-protective activies against benzo(a)pyrene poisoning.

천연자원을 이용한 간기능 증진제 개발 연구 : Benzo(a)pyrene에 의해 유도된 간기능 장해에 미치는 천궁 추출액의 영향 The Effect of Cnidii Rhizoma on Benzo(a) Pyrene Induced Hepatotoxicity

尹水弘,이송애,하헌,박은주,오관현 대구효성가톨릭대학교 1993 연구논문집 Vol.46 No.1

The present study was undertaken to compare the pharmacological activity of crude Cnidii Rhizoma reported with the clinical uses in the oriental medicine. Crude Cnidii Rhizoma used for the treatment of anemia, body chill, menstural irregularity and menstural pain as hematic tonic effector, sedative, adodyne and clear extravasated blood. Therefore we tested the effects of Cnidii Rhizoma water extract on the liverprotective activities in the rats. The results obtained form liver microsomal enzyme assay, measurement of serum and liver alanine, aspartate aminotransferase and lipid accumulation indicated that Cnidii Rhizoma extract showed significant liver-protective activities against benzo(a)pyrene poisoning.

머리염색이 인체에 미치는 영향

윤형식,황성호,이현륭,김수호,박연석,권낙현,정호진,김동훈,노현주,홍성호,박병찬,이관,정해관 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

일상생활에서 모발염색은 흔히 접할 수 있는 미용의 한 종류로 특히 젊은층을 중심으로 폭발적으로 유행하고 있다. 염색을 위항 사용하는 약제는 표백제와 발색제 등 각종 화학약품이 사용되고 있으나 이로 인한 건강장해에 대한 연구는 그리 많지 않다. 저자들은 염색이 인체의 모발건강에 미치는 영향을 파악하기 위하여 염색과 관련된 주관적 증상과 모발의 변화에 대한 실험적 연구를 시행하였다. 동국대학교 경주 캠퍼스 재학생 80명을 대상으로 설문조사를 시행하여 염색 유 ·무 및 염색 후에 경험한 증상에 대해 설문 조사하였고, 의과대학 재학생 46명을 대상으로 피부 반응 테스트를 실시하였다. 또한 염색 전후의 모발 탄성도를 측정하였고 모발의 상태를 파악하기 위해 전자 현미경검사를 실시하였다. 설문조사 결과 염색 전에 비하여 염색 후 안구혼탁, 안구건조, 시력저하, 발진 및 접촉성 피부염, 모발손상, 모근손상 등의 증상을 더 많이 경험한다고 호소하였다(p<0.05). 모발손상과 모근손상은 헤어드라이어 사용 빈도에 따라 증가하는 것으로 조사되었다(p<0.05). 피부반응검사에서 가려움증이 가장 많은 증상이었으며 이는 여성보다는 남성에서 높은 것으로 조사되었다. 염색 전후의 모발장력은 염색 전 134.5±10.37g, 염색 128.0±30.69g, 염색 이틀 후 112.5±19.69g으로 나타났다. 염색 전후의 모발의 전자현미경 케라틴 층이 현저히 감소하고 모발이 가늘어지는 차이를 보였다. 염색은 모발손상, 모발 케라틴 손상 및 모근 손상, 발진 및 접촉성 피부반응, 안구혼탁, 안구건조, 시력 저하를 유발한다. 따라서 염색약으로 인한 손상에 대한 주의와 예방이 필요하다고 생각한다. 예방대책으로 염색 전 피부테스트를 통한 적합성 여부를 판단하는 것이 필요하며 가급적 염색을 피하는 것이 좋을 것이다. 염색약에 발암물질이 포함되어있다는 보고도 있어 염색 제조사의 철저한 실험과 염색 물질의 선별이 염색으로 인한 부작용을 최소화하는데 중요한 역할을 할 것이다. Hair coloring has became one of the most popular cosmetic activities to younger generations during last decade. However, there are few studies on the health effect of widespread use of chemical dyes. This study was conducted to study the effects of hair coloring dye on hair and other systems. We conducted a questionnaire survey of 80 persons in Kyongju campus, Dongguk University. We have done open patch skin test on 46 medical students. We also conducted scanning electron microscopy to examine the hair strength and structure before and after hair coloring process. Injury of hair and hair bulb, contact dermatitis, turbid eyes, xerophthalmia, and poor visual acuity were the main symptoms complained after hair coloring (p<0.05). Injury of hair and hair bulb were increased by frequency of hair-dryer use(p<0.05). In open patch test, pruritus was complanined by more than half of the subjects. Mean strength of hairs before and after hair coloring was as follows; 134.5 (SD 10.37)g before hair coloring, 128.0 (SD 30.69)g immediately after hair coloring, and 112.5 (SD 19.69)g after two days. The scanning electron microscopic findings of hair surface before and after hair coloring showed decreased keratin layer and thinning of the hair. Hair coloring induces injury to hair, its keratin layer, and hair bulb as well as contact dermatitis, turbid eyes, xerophthalmia, and poor visual acuity. Therefore, we think that precaution is needed in use of hair coloring dye. To prevent complications induced by hair coloring dye, it is necessary, especially to those with allergy or skin disorders, to perform skin test before action and avoid hair coloring whenever possible. Longterm health effects of hairdye should be studied and manufacturing companies should try to minimize complications induced by hair coloring dye.

슬라이딩 모드를 이용한 LDM 서보밸브의 추종제어

윤신용,백수현 동국대학교 산업기술연구원 1999 산업기술논문집 Vol.13 No.-

본 논문은 LDM을 이용한 직접구동 서보밸브의 위치 추종제어를 연구하였다. 선형 전자석 솔레노이드로 구동되는 노즐 플레퍼형 서보밸브와 비례 선형 밸브는 공장 자동화 분야에 광범위하게 적용된다. 이러한 고전적인 서보밸브는 효율, 오염, 저속에서 문제점을 지니고 있기 때문에, 고속 및 고정밀 서보밸브가 요구된다. 따라서 본 연구에서는 LDM을 이용한 고속 하이드라릭 서보밸브를 적용한다. 제어는 슬라이딩 모드인 새로운 형태의 상태 공간 궤적을 이용한다. 가변구조시스템 (슬라이딩모드)은 적합한 스위칭 로직과 함께 연속적 특성을 갖는 종속시스템으로 가변구조시스템을 구성하고 있다. 따라서 본 연구에서는 슬라이딩모드 제어기법을 이용한 최적의 성능을 갖는 시스템을 제안한다. This paper deals with a position sliding mode control of direct drive hydraulic servo valve(linear servo valve, LSV) using linear DC motor (LDM). The nozzle-flapper type servo valves and proportional linear valves driven linear electromagnetic solenoid are widely used in factory automation. Because these conventional valves involve problems in efficiency, contamination and low-speed. High speed and hi precision servo valves have been required. This paper is applied to high speed hydraulic servo valve using LDM. The controller is designed so that a new type of state space trajectories called sliding mode exists. Variable structure system (sliding mode) consist of a set of continuous subsystems together with suitable switching logic. Therefore, a sliding mode control has the control performance very near to the time optimal one.

저마찰인공고관절전치환술의 X선학적 고찰

윤종섭,고재휴,김영용,곽현수 대한의학협회 1975 대한의학협회지 Vol.18 No.7

Candida albicans의 표면 iC3b 수용체 발현 및 혈관 내피세포에 대한 유착

이광훈,윤문수,윤경한,최현주 대한의진균학회 1996 대한의진균학회지 Vol.1 No.1

Background: The adherence of microorganisms to host tissue is an important process in the pathogenesis of fungal infection. A protein that shares antigenic and structural homology with the α-subunit of leukocyte adhesion glycoprotein CD11b/CD18, also known as iC3b receptor, Mo-1 or Mac-1, has been isolated from the surface of C. albicans. Objective: This study was done to observe the changes in the expression of iC3b receptor on C. albicans by glucose or immunosuppressive agents and to elucidate the effect of glucose and anti-iC3b receptor antibodies on adhesion between human dermal microvascular endothelial cells(HDMEC) and C. albicans. Methods: We utilized immunofluorescence study and immunofluorescent flow cytometry and the binding assay of C. albicans to cultured HDMEC in vitro and blocking assay using monoclonal antibody were performed. Results: Immunofluorescence study and immunofluorescent flow cytometric analysis demonstrated surface expression of iC3b receptor on C. albicans The expression of surface iC3b receptor on C. albicans in creased in a dose dependent manner with increasing concentrations of glucose, cyclophosphamide and prednisolone. The adherence of C. albicans to HDMEC correlated positively with glucose levels. The adherence of C. albicans to HDMEC decreased significantly by the treatment with anti-iC3b receptor antibodies. Conclusion: The results suggest that iC3b receptors should be involved in the adherence of C. albicans to vascular endothelial cells and may be involved in the pathogenesis of hematogenous candidiasis.