• 한국광학회지
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• 제31권1호
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• pp.13-19
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• 2020

광섬유 사냑 간섭형 센서를 이용해 수중 음향을 측정하기 위하여 링형 탐촉자를 적용하는 경우 민감도를 이론과 실험을 통하여 조사한다. 링형 탐촉자는 단일 모드 광섬유를 지름 5 cm의 링형으로 감아서 접착제로 패키징하였다. 링형 탐촉자는 감지 광섬유의 길이를 46.84 m로 하여 제작한 A형 탐촉자와 감지 광섬유의 길이를 112.22 m로 한 B형 탐촉자를 준비하였다. 수중 음향 시험은 상용 음향 발생기와 1 m 떨어진 거리에서 링형 탐촉자를 사용하여 50, 70, 90 kHz의 주파수에 대하여 20~100 Pa의 음향 압력 범위에서 음향 민감도를 조사하는 실험을 수행하였다. 실험 결과, 링형 탐촉자는 주파수에 대하여 다른 민감도를 나타내었으며, 이론과 비교하기 위하여 평균값을 구하였다. 세 주파수에 대한 평균 민감도는 A 탐촉자와 B 탐촉자에 대하여 각각 25.48 × 10^-5, 60.79 × 10^-5 rad/Pa으로 측정되었으며, 이로부터 영률 보정 계수 c값을 0.35로 결정할 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제13권3호
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• pp.1285-1293
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• 2018

This paper proposes a new type of consequent-pole permanent-magnet (CPPM) machine with stator axial magnetic ring that increases torque capability over a wide speed range and enhances efficiency for the built-in rare-earth permanent magnet synchronous machine used in new energy vehicles. The excitation winding of the CPPM hybrid excitation synchronous machine in the stator is replaced by ferrite magnetic ring to simplify the structure and manufacturing process of the machine. The basic structure and magnetic regulation principle of the proposed machine are introduced and compared with the traditional interior rare-earth permanent magnet synchronous machine and CPPM hybrid excitation synchronous machine. Finally, experimental results of a new type of CPPM synchronous motor prototype with axial magnetic ring are introduced in the paper.

• 한국기계가공학회지
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• 제19권8호
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• pp.22-27
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• 2020

Ring rolling is a type of forging for manufacturing large-diameter rings. Products manufactured by ring rolling are useful in the aerospace industry because of their excellent mechanical properties and high dimensional accuracy. The major components of the ring rolling process are a mandrel and main roll that shape the inside and outside of the ring, an axial roll that shapes the top and bottom of the ring, and a side rolls to position the ring. In this study, a simulation of ring rolling using finite element method (FEM) was performed. DEFORM, a commercial machining analysis program, was used. Based on the simulations, the mandrel feed force required for machining and the drive torque of the main roll were predicted. It was also possible to identify the metal flow caused by machining.

• 한국광학회지
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• 제7권4호
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• pp.386-389
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• 1996

We report on comparative results obtained from harmonically mode-locked laser operations of ring-type and figure-of-eight(F8) type erbium-doped fiber lasers by using a directional-coupler type electro-optic modulator as an active mode-locker. The mode-locked and transform-limited pulses of 10.6 ps width were obtained at harmonics of the fundamental cavity frequency with the F8 type laser while mode-locked laser pulses greater than 15 ps were achieved with the ring type laser.

• 한국안전학회지
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• 제32권3호
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• pp.117-122
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• 2017

In this study, we studied the ride quality considering the deterioration effects of the three type couplers (single, double, and ring types) for EMUs. In order to know the impact occurred when an urban transit vehicle is under breaking, we tested the conditions of the service brake and the emergency brake. Normal coupler models without any slack showed similar dynamic performance results under all breaking conditions. But if the couplers become old, the initial pre-stresses are removed because of permanent compressive deformation in rubber. For three types of the old coupler models without the initial pre-stress, we evaluated dynamic performances of each type. As the results, the maximum and average acceleration levels of the double type and the ring type were similarly low in all conditions. But the accelerations of the single type coupler was high when compared to those of the double and ring types. In addition, Jerk value of the single type model associated with ride quality was high up to 15 times to the ring type in condition of the service braking in empty vehicle weight. Jerk value of the double type model was high up to 6 times to the ring type.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1034-1037
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• 2002

A switched-capacitor(SC) type DC-DC converter having capability of integrated circuit fabrication have been marked for the application of mobile equipments. Especially, a ring type SC power supply is featured by the flexible and dynamic voltage conversion ratio change. In this paper, an improvement of the gate driving techniques is proposed for high power efficiency and less area occupation on the chip. Furthermore, its power-saving operation in the stand-by state is proposed. The three-capacitors ring type power supply is really designed and discussed. As results, the simulation results shows the high efficiency of 92.1%, and the higher output put voltage of 10.5 V compared with conventional one of 8.6 V.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권4호
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• pp.173-178
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• 2003

The rotational force of ultrasonic motors is able to get from the frictional force of elliptical vibration by contact between rotor and stator. Generally, ultrasonic motors are suitable for driving at resonant frequencies of about 20∼80［KHz］. The driving characteristics of ring type ultrasonic motors are the object of this study. A two-phase driving signal is delivered to the tested ultrasonic motor, which has a $90^0$ phase difference respectively with both sine and cosine voltage waveforms. The driving frequency is almost equal to the mechanical resonant frequency for the proper operation, and the driving signal is supplied by the two-phase parallel resonant inverter. The validity of the proposed driving method is verified by experimental results with stable operation.

• 한국정밀공학회지
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• 제18권9호
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• pp.140-146
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• 2001

Seals in a universal joint bearing are important components reinforcing lubrication performance by holding lubricant and preventing infiltration of dust, moisture, etc.. There is a great difference in seal performance according to seal shape and bonding position. Therefore, in this study, as for both the lip type seal and the O-ring type seal, FE analysis is conducted using Mooned-Rivlin Model. The results show that O-ring type seal does not have any effect of misalignment angle compared with lib type seal, which is more profitable.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2000년도 암반공학문제의 수치해석(Numerical Analysis in Rock Engineering Problems)
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• pp.63-66
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• 2000

링 시험펀의 크기와 편심에 따른 응력변화를 FLAC으로 분석하였다. 분석 결과 중공의 크기가 일정한 범위에서만 안정된 값을 얻을 수 있었다. 중공의 크기 오차를 줄이기 위한 상대 공반경은 약 0.3이 적절할 것으로 평가되었다. 한편 중공의 관심 오차가 커지면 응력분포가 불균일하게 되어 정확한 인장강도 산정이 어려운 것으로 사료되었다. 적절한 인장강도를 얻기 위해 중공의 편차는 일정한 정도로 한정하여야 할 것으로 생각된다. 편심으로 인한 오차를 10% 이내로 제한하기 위해서는 중공의 중심은 가압방향에 수평한 방향으로 3%, 수직한 방향으로는 10% 이내가 되어야 하는 것으로 분석되었다.

• 터널과지하공간
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• 제10권3호
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• pp.316-319
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• 2000

링 시험편의 크기와 편심에 따른 응력변화를 FLAC으로 분석하였다. 분석 결과 중공의 크기가 일정한 범위에서만 안정된 값을 얻을 수 있었다. 중공의 크기 오차를 줄이기 위한 상대 공반경은 약 0.3이 적절할 것으로 평가되었다. 한편 중공의 편심 오차가 커지면 응력분포가 불균일하게 되어 정확한 인장강도 산정이 어려운 것으로 사료되었다. 적절한 인장강도를 얻기 위해 중공의 편차는 일정한 정도로 한정하여야 할 것으로 생각된다. 편심으로 인한 오차를 10% 이내로 제한하기 위해서는 중공의 중심은 가압방향에 수평한 방향으로 3%, 수직한 방향으로는 10% 이내가 되어야 하는 것으로 분석되었다.