• 한국유변학회:학술대회논문집
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• 한국유변학회 2000년도 추계 학술발표회 논문집
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• pp.21-24
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• 2000

• 한국전산유체공학회지
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• 제11권3호
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• pp.64-70
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• 2006

A Computational study was carried out in order to investigate the moving wall effect of a circular cylinder at a Reynolds number of $2.0{\times}10^4$. The viscous-incompressible Navier-Stokes equations and Spalart-Almaras turbulent model of the commercial CFD code were adopted for this numerical analysis. The moving wall was set parallel with the freestream, and moving speed was equal to the freestream velocity. The gap ratio is defined as the distance ratio between the circular cylinder diameter and the height from the moving wall. The results show that there is vortex shedding over the critical gap ratio and aerodynamic loads including amplitude and the Strouhal number change according to the gap ratio.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.302-307
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• 2004

The major flow-induced vibration mechanisms such as fluid-elastic and turbulence excitation can cause the various types of wear of the steam generator tubes in unclear power plant. It is generally accepted that the tube wear due to vibration is affected by the presence of gap clearance between tube and support plate. Connors showed that the tube wear depth could be estimated by using the relationship between wear volume and sliding distance for contact time. Au-Yang predicted the wear depth by using the nonlinear characteristics of normal work rate to contact time. In this study the effect of gap size on the steam generator tubes wear is analyzed by deriving the wear depth versus normal work rate relationship from these previous results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.172-174
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• 2007

A propeller shaft is the device which is used to transmit the power between two shafts in a vehicles, an industrial machinery, etc. The end of spline is worm due to the deflection of the propeller shaft, and a lifetime of it is reduced, because it for industrial machinery has the length of 2,500 mm, the weight of $300\;kg_{f},$ and the sliding distance of $\pm250\;mm.$ Accordingly in this study we analyzed the effect of the gap of spline on the deflection of a propeller shaft carrying out the finite element analysis, in order to determine the proper gap of spline to minimize the deflection of it. We adopt 10-kinds of gap of spline from 0.05 mm to 0.5 mm at interval of 0.05 mm as the design parameter for the finite element analysis and the centrifugal force as the load condition.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.366-367
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• 2008

SF6 widely used as insulating gas is rising as the environment problem. For decreasing this greenhouse gas, electrical breakdown characteristics of vacuum with air are studied in non-uniform field. The gap of needle to plane was 0.5mm, 0.8mm. The pressure of vacuum the range of 10^-4-10^-5torr. The diameter of a plane made of the stainless steel is150mm. As a result of the experiment, the breakdown voltage is increased about electrode gap distance increased. The electrode material influenced breakdown voltage in vacuum.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.267-269
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• 1994

Various types of plasma display panels(PDPs) have been developed to realize the flat panel display device. But, many of its characteristics must be improved before it can be commercialized. In order to investigate tile characteristics of micro discharge in a PDP ceil, we have constructed a micro-gap discharge system whose electrode gap can be adjustable between $100-1000{\mu}m$ within $0.1{\mu}m$ accuracy. We measured the minimum sustain voltage, current, delay time of discharge while changing parameters(electrode gap distance, electrode surface area, pressure) which influence discharge characteristics.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.352-354
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• 2022

카메라를 이용한 위치 측정은 오랫동안 많은 연구가 진행되고 있다. 이것은 자율주행 자동차에서 차간거리 인식이나 객체 인식을 위한 연구가 있고, GPS를 적용하기 어려운 한정된 공간인 실내의 내비게이션 분야에서 연구되고 있다. 보통, 카메라를 이용하는 거리를 측정하는 방법은 2개의 스테레오 카메라를 이용하여 카메라 사이의 거리와 촬영된 영상이나 사진을 통해 측정된 값을 이용하여 거리를 측정한다. 본 논문에서는 하나의 카메라를 이용하여 사물의 거리를 측정하는 방법을 제안한다. 제안하는 방법은 촬영 시간의 차이, 촬영 사이의 거리를 통하여 스테레오 카메라와 같이 카메라 간의 거리, 촬영된 사진에 의해 측정된 값을 이용하여 거리를 측정한다.

• 한국초전도ㆍ저온공학회논문지
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• 제13권1호
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• pp.41-45
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• 2011

Hybrid fault current limiters (FCL) have been researched at Yonsei University. The hybrid FCL has advantages such as having a rapid response to a sudden fault situation and a fast recovery time from a quench. It consists of an asymmetric HTS coil, a switching module, and a bypass reactor. The asymmetric HTS coil is wound with two different types of HTS wires in an opposite direction so that it has nearly zero inductance at the superconducting state. When the quench occurs at the fault state, a strong magnetic field is generated from the asymmetric coil because of different quench characteristics of two HTS wires, and then a repulsive force is induced in the switching module. The force opens the switch and the fault current is pushed into the bypass reactor. In this research, we analyzed the cause of the repulsive force and confirmed, experimentally and computationally, that the magnitude of a repulsive force is varied by changing the gap distance between the asymmetric coil and the switching module. By using the FEM simulation, we calculated the repulsive force with respect to the gap distance and verified that the effect of the gap distance. Then, short circuit test was carried out to confirm the correct operation of the fast switch.

• 대한치과기공학회지
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• 제28권1호
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• pp.53-59
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• 2006

The movement range on the semi adjustable articulator and the movement range in an oral were measured. And then I studied to analyze the gap. I got wax records by the movement on the semi adjustable articulator, the movement in an oral. I measured the distance of the cusp tips that are close to the mesial direction and the distal direction, the buccal direction and the lingual direction then I compared gaps. As I saw results on data, I knew that the semi adjustable articulator represented the range of mandibular movement restrictively. I could find the decisive contradiction that the sliding movement finished on the semi adjustable articulator although it did not finish in an oral. When the sliding movement does not reappear exactly, it brings a fatal failure to the dental prosthesis. In addition it is impossible that the semi adjustable articulator restores the movement in an oral because the lateral condyle inclination and the horizontal condyle inclination are appeared to be straight. Therefore dental prosthesisses were made by the semi adjustable articulator, they will interfere with a mastication. I have obtained the following results; 1. The distance of sliding movement on the semi adjustable articulator showed shorter than the distance of sliding movement in oral. This means the increase of cusp inclination of the dental prosthesis that was made on the semi adjustable articulator. Therefore, when the lateral movement occurs in oral, there is a possibility to become the premature as the increase of cusp inclination. 2. The difference in the range of movement is considered as the gap that is made because the movement only can be occurred as straight in the semi adjustable articulator. 3. When the dental technician understand mandibular movement and articulator deficiencies, they can attain proficiency in use of the articulator and reduce the gap.

• 대한치과기공학회지
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• 제25권1호
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• pp.111-118
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• 2003

I measured the movement range on the hinge articulator and the movement range in an oral. And then I studied to analyze the gap. I got wax records by the movement on the hinge articulator, the movement in an oral and the movement on the hand articulating. I measured the distance of the cusp tips that are close to the mesial direction and the distal direction, the buccal direction and the lingual direction then I compared gaps. As I saw results on data, I knew that the hinge articulator represented the range of mandibular movement restrictively. I could find the decisive contradiction that the sliding movement finished on the hinge articulator although it did not finish in an oral. If the sliding movement does not reappear exactly, it brings a fatal failure to the dental prosthesis. In addition it is impossible that the hinge articulator restores the movement in an oral because the lateral condyle inclination and the horizontal condyle inclination are fixed previously. Therefore dental prosthesisses were made by the hinge articulator, they will interfere with a mastication. I have obtained the following results; 1. The distance of sliding movement on the hinge articulator showed shorter than the distance of sliding movement in oral. This means the increase of cusp inclination of the dental prosthesis that was made on the hinge articulator. Therefore, when the lateral movement occurs in oral, there is a possibility to become the premature as the increase of cusp inclination. 2. The results that were impressed records in oral and impressed records on the hand articulating have many congruities. I think that the simple crown etc. that were made by the hand articulating method except the long span bridge and the free end case that can not measure the vertical dimension exactly can represent similarly the mandibular movement. 3. If we want to represent the mandibular movement similarly, we have to use the articulator that can adjust the horizontal condyle inclination and the lateral condyle inclination at least.