• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.379-382
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• 2000

The characteristics of Xe discharge lamp(Mercuryless lamp) are described in this paper. In this paper, FFL is operated by sine wave and pulsed source. We apply V-Q Lissajous' figure for the discharge measurements of FFL which has the electrodes covered with dielectric. When FFL is operated by sine wave source, the characteristics are similar to DBD(Dielectric Barrier Discharge) and SD(Silent Discharge). And we compared the characteristics of FFL which is operated with sine wave and pulsed discharge by using V-Q Lissajous' figure method. When FFL is operated with pulsed, the discharge current flows after the applied voltage is risen. As the duty ratio increases the electric field becomes strong and much more xenon ions are produced. And the number of metastable xenon atoms seem to increase, therefore, the phosphor radiation after the cut off of voltage increases compared with the first peak of radiation. Consequently, the 172㎚ radiation becomes strong as the duty ratio increases.

• 한국산학기술학회논문지
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• 제10권12호
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• pp.3755-3760
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• 2009

본 연구에서는 천연가스 처리공정 및 석유화학 공정의 Saturated gas plant에서 주로 사용되고 있는 탈에탄탑(Deethanizer)에 대한 설계 과정과 재비기의 heat duty를 최소화시킬 수 있는 원료 주입단의 위치를 최적화시켰다. 탈에탄탑의 공정 모사를 위해서 상용성 모사기인 Invensys사의 PRO/II with PROVISION을 사용하였으며, 열역학 모델식으로는 Soave가 변형시킨 Redlich-Kwong 상태방정식을 사용하였다. 본 연구를 통해서 분리를 위한 최소이론단수는 9.02단이며, 최소환류비는 0.62437이며, 최적의 이론단수는 20단이며, 최적의 원료 주입단은 9단이고 이때 재비기의 heat duty의 최소값은 $12.7470{\times}10^6\;KJ/hr$임을 알 수 있었다.

• 전기학회논문지
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• 제65권12호
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• pp.2197-2210
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• 2016

Recently, the trend of zero emissions has increased in automotive engineering because of environmental problems and regulations. Therefore, the development of battery electric vehicles (EVs), hybrid/plug-in hybrid electric vehicles (HEVs/PHEVs), and fuel cell electric vehicles (FCEVs) has been mainstreamed. In particular, for light-duty electric vehicles, improvement in electric motor performance is directly linked to driving range and driving performance. In this paper, using an improved design for the interior permanent magnet synchronous motor (IPMSM), the EV driving range for the light-duty EV was extended. In the electromagnetic design process, a 2D finite element method (FEM) was used. Furthermore, to consider mechanical stress, ANSYS Workbench was adopted. To conduct a vehicle simulation, the vehicle was modeled to include an electric motor model, energy storage model, and regenerative braking. From these results, using the advanced vehicle simulator (ADVISOR) based on MATLAB Simulink, a vehicle simulation was performed, and the effects of the improved design were described.

• 한국분무공학회지
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• 제21권3호
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• pp.130-136
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• 2016

NOx and PM are important air pollutants as vehicle management policy aspect. Medium-duty truck is the main source of the pollutants although the vehicle market share is only 3.5%. National emission portion of NOx and PM form the mobile sourece are 14% and 16% respectively. In this study it was investigated that characteristics of air pollutants emission on medium duty truck equipped with EGR and SCR system. Vehicle's test reflected driving cycle on the chassis dynamometer, and applied test cycle was WHVC(World Harmonized Vehicle Cycle) mode. The test cycle include three segments, represent urban, rural and motorway driving. Based on the test results NOx, PM, HC were less emitted form SCR vehicle than EGR vehicle. And CO was less emitted form EGR vehicle than SCR vehicle due to CO oxidation reaction on DPF surface. And most air pollutants reduced as average vehicle speed increased. Pollutants were less emitted on motorway section than urban and rural sections. But highly NOx emission on motorway section was verified according to increased EGR ratio on fast vehicle speed. HC and CO additional emission was identified as 68%, 58% respectively during SCR vehicle's cold engine start emission test. NOx additional emission was detected by 24% on SCR vehicle's condition of engine cold start while not detected on vehicle equipped with EGR. SCR vehicle's additional NOx emission was derived from low reaction temperature during engine cold start condition. medium-duty truck emission characteristics were investigated in this study and expected to used to improve air pollutants management policy of medium-duty truck equipped with SCR & EGR.

• The Korean Journal of Physiology
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• 제1권2호
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• pp.199-213
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• 1967

Circulatory and respiratory activities were observed in men exposed to the environment of engine room of a cruising Republic of Korea Navy ship and compared to the control values obtained in an ordinary laboratory room on land. The environment of an engine room of cruising navy ship was presumed to be a multiple stress acting on men. The environment of the engine room included high temperature $(35-42^{\circ}C)$, low relative humidity (20-38% saturation), vibration (about 7 cycles per second), rolling and pitching of ship and noises. Sixteen men were divided into two groups consisted of each 8 subjects. Subjects of sea duty group had experience of continuous on board duty averaging 3.5 years. Men of land duty group had no experience of on board activity. On land observations were made on one day prior to the boarding and leaving the port and four days after landing. In between observations in the engine room were made on the first, 5 th, 9 th, 12 th, and 14 th day of on board activity. The whole experimental period lasted for 20 days. Measurements on circulatory and respiratory parameters were at standing resting state (after 30 minutes standing in the case of on land study and 15 minutes in engine room study) and within one minute after cessation of on the spot running of which rhythm was 30/min. and lasted for 5 minutes. Oxygen consumption and pulmonary function test were done in the period of two minutes from the 3rd to 5th minutes of running. The following results were obtained. 1. Body temperature showed no change regardless of group difference or on land or on board measurements. 2. Pulse rate increased markedly after boarding the ship id both groups. Pulse rate increased from the first day on board at rest and after exercise as compared to the on land control value. This increase in pulse rate was more marked after exercise. Sea duty group showed less increase in pulse rate at rest than the land duty group. Standing and resting pulse rate of sea duty group on lam was 81 and increased to 87 at the 5th day on board and remained smaller than the land duty group throughout the period on board. Control standing and resting pulse rate of land duty group on land was 76 and reached 89 at the 9th day on board and thereafter decreased a little. Pulse rate of land duty group at rest on board remained greater than that of sea duty group throughout the period on board. 3. Systolic blood pressure of sea duty group increased after boarding the ship and remained higher than the control value on land. In the land duty group, however, systolic blood pressure decreased during the period on board the ship. Diastolic blood pressure decreased in both groups. 4. Resting breathing rate of land duty group increased and remained higher than the control value on land. In sea duty group, however, resting breathing rate showed a transient increase on the 1st day on board and decreased thereafter to the control value on land and kept the same level throughout the period of cruise. Absolute value of breathing rate in the sea duty group was greater than the land duty group both at rest and after exercise. 5. There was a lowering of breathing efficiency in both groups. Thus, increases in tidal volume and minute ventilation volume and decreases in maximum breathing capacity, vital capacity, capacity ratio and air velocity Index were observed after boarding the ship. An increase in ventilation equivalent was also observed in both groups. The lowering of breathing efficiency was more marked in the land duty group than the sea duty group. 6. Energy expediture increased in both groups during their stay on the ship and was more marked in the sea duty group. 7, Lactate concentration in venous blood at rest and after exercise increased after boarding the ship and no group difference was observed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1196-1200
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• 2004

Micropump is very useful component in micro/nano fluidics and bioMEMS applications. In this study, a bubble-powered micropump was fabricated and tested. The micropump consists of two-parallel micro line heaters, a pair of nozzle-diffuser flow controller and a 1 mm in diameter, 400 ${\mu}m$ in depth pumping chamber. The two-parallel micro line heaters with 20 ${\mu}m-width$ and 200 ${\mu}m-length$ were fabricated to be embedded in the silicon dioxide layer of a wafer which serves as a base plate for the micropump. The pumping chamber, the pair of nozzle-diffuser unit and microchannels including the liquid inlet and outlet port were fabricated by etching through another silicon wafer. A glass wafer (thickness of $525{\pm}15$ ${\mu}m$) having two holes of inlet and outlet ports of liquid serve as upper plate of the pump. Finally the silicon wafer of the base plate, the silicon wafer of pumping chamber and the glass wafer were aligned and bonded (Si-Si bonding and anodic bonding). A sequential photograph of bubble nucleation, growth and collapse was visualized by CCD camera. Clearly liquid flow through the nozzle during the period of bubble growth and slight back flow of liquid at the end of collapsing period can be seen. The mass flow rate was found to be dependent on the duty ratio and the operation frequency. As duty ratio increases, flow rate decreases gradually when the duty ratio exceeds 60%. Also as the operation frequency increases, the flow rate of the micropump decreases slightly.

• 전력전자학회논문지
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• 제14권2호
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• pp.142-149
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• 2009

본 논문은 단위 역률을 갖도록 직접 시비율 펄스폭 변조 방식으로 제어되는 3상 매트릭스 컨버터의 평형 및 불평형 부하시의 동작 특성을 고찰한다. 시스템의 해석으로부터 얻어진 중요하고 유용한 사실을 정리하면 다음과 같다. (1) 단위 역률 제어 알고리즘은 부하측의 변수에 의해서가 아니라 입력전압에 의하여 정해진다. (2) 평형 3상 부하가 리액티브 부하인 경우만 아니라면 입력측 역률을 1로 만들 수 있다. (3) 불평형 선형부하의 경우, 매트릭스 컨버터의 등가입력 특성은 비선형저항과 같다. (4) 입력 주파수와 출력 주파수가 특정한 관계를 가질 때, 입력측의 각상은 동일한 평균전력 분담률을 갖는다. 해석의 타당성과 유효성은 시뮬레이션과 실험결과를 통하여 검증하였다.

• 전자공학회논문지SC
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• 제42권3호
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• pp.63-70
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• 2005

유도방전을 이용한 무전극 램프는 전극을 필요로 하지 않기 때문에 긴 수명을 갖으며 안정기 출력의 변화에 대해서도 매우 강한 특성을 갖는다. 본 논문에서는 무전극 램프 조광제어를 위한 두 가지 새로운 알고리즘을 제안하였고 이를 적용한 공진형 인버터에 대하여 기술하였다. 제안된 두 가지 조광제어 알고리즘은 주로 LCD 백라이트의 조광제어에 적용되는 버스트 디밍 기법을 기초로 한다. 제안된 두 가지 방식중 하나는 개선된 버스트 디밍 기법으로 간단한 디지털 논리회로를 이용한 제어회로를 통해 $5\%$ 단위의 시비율로 조도조절이 가능한 방식이며, 나머지 하나는 버스트 PWM 평균 시비율 제어 기법으로 다소 복잡한 제어회로를 통해 $1\%$ 단위의 시비율로 조도조절이 가능한 방식이다. 본 논문에서는 100W급 무전극 램프를 대상으로 실시한 실험결과를 통해 제안된 조광제어 알고리즘의 유효성을 입증하였다.

• 한국재료학회지
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• 제25권11호
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• pp.616-621
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• 2015

Atmospheric pressure plasma is used in the biological and medical fields. Miniaturization and safety are important in the application of apply atmospheric plasma to bio devices. In this study, we made a small, pocket-sized inverter for the discharge of atmospheric plasma. We used pulse power to control the neutral gas temperature at which the, when plasma was discharged. We used direct current of 5 V of bias(voltage). The output voltage is about 1 to 2 kilo volts the frequency is about 80 kilo hertz. We analyzsed the characteristics of the atmospheric plasma using OES(Optical emission spectroscopy) and the Current-Voltage characteristic of pulse power. By calculating of the current voltage characteristics, we were able to determine that, when the duty ratio increased, the power that actually effects the plasma discharge also increased. To apply atmospheric plasma to human organisms, the temperature is the most important factor, we were able to control the temperature by modulating the pulse power duty ratio. This means we can use atmospheric plasma on the human body or in other areas of the medical field.

• 한국재료학회지
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• 제11권6호
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• pp.441-447
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• 2001

PACVD 방법으로 다이캐스팅용 금형에 적용할 수 있는 TiN 코팅막을 형성시키는 연구를 하였다. 직류 펄스전원을 사용하여 지름이 4 mm인 작은 동공내부에 최고 20 mm 깊이까지 균일한 TiN 코팅층을 형성할 수 있었다. 코팅공정시 발광분광분석기를 사용해 Ti와 $N_{2}$ 및 $Ar^{+}$의 분광선을 측정함으로써 TiN 코팅막의 형성기구에 대하여 고찰하였다. 듀티비율이 50% 이상인 경우는 Ti, $N_{2}^{+}$ 및 $Ar^{+ }$ 의 분광선이 나타났으나, 듀터비율이 28.6%이하인 경우 분광선이 전혀 나타나지 않았으며 TiN 코팅층의 형성도 불안정하였다. 펄스전원으로 Bipolar로 사용한 경우 Unipolar를 사용한 경우보다 지름이 4 mm인 구멍에서 2배 깊게 코팅되었다.