• The Korean Journal of Rheology
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• v.11 no.2
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• pp.73-81
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• 1999

The intention of this research is to give criteria of designing devices using ER fluids and MR fluids. The Properties of commercial ER fluids and MR fluids are compared using a rotational viscometer. The yield strength is compared upon changes of shear rate, temperature and applied fields. MR fluids seem less sensitive to temperature change than ER fluids. In cases of MR and ER fluid dampers, the time delay and damping force are measured in tension and compression mode when the applied field changes.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1389-1394
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• 2004

Experiments were done for the unsteady flow in a counter rotating axial flow fan near peak efficiency and stall point. Flow fields in a counter rotating axial flow fan were measured at cross-sectional planes of the upstream and downstream of each rotor. Cross sectional passage flow patterns were investigated through the acquired data by the $45^{\circ}$ inclined hot-wire. Comparison of flow characteristics between two different operating conditions such as tip vortex, secondary flow and turbulence intensity were performed through the analyses of axial, radial and tangential velocity distributions. As a result, tip vortex and secondary flows are enforced and measured obviously at stall point.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2039_2040
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• 2009

본 논문은 리세트(reset) 제어이론과 상태궤환 안정성 기법을 이용하여 회전식 역진자 시스템의 강인제어시스템을 제안한다. 우선 복잡한 비선형 역진자 시스템을 평형점에서 선형화한 후 상태궤환기법을 이용하여 안정한 모델을 구성한다. 이 선형시스템 모델에서 발생할 수 있는 시스템 섭동으로 인한 실시간 제어오차를 보상하기 위한 리세트 제어알고리즘을 보조제어시스템으로 추가한다. 컴퓨터 시뮬레이션을 통해 제안한 제어 알고리즘의 타당성 및 성능의 개선정도를 분석한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1590-1597
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• 1994

The aerodynamic analysis of a $6{\times}6$ counter-rotating propfan around a missile-like-body has been completed analytically using a frequency domain panel method. The present method requires Fourier transformation of flow field around the propfan in computing the velocities normal to the propfan lifting surfaces. The aerodynamic performance curve is determined by angle of attack and nonuniform inflow conditions. The inflow conditions result from the variations of missile flight speed, angle of attack, propfan location relative to control surfaces and control surface deflection angle. The two cases of propfan location relative to control surface, front and behind, are analyzed and the aerodynamic results are presented.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.441-446
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• 2000

The experiments of the Aerodynamic characteristics of a counter-rotating axial fan were carried out. The performance tests of a single and a counter-rotating axial fan were carried out based on the Korean Standard Testing Methods for Turbo-fans and Blowers(KS B 6311). The performances of single and counter-rotating axial fans were obtained and compared with each other. The flow fields of a counter-rotating axial fan at the peak efficiency point were measured using a five-hole probe. As a result, compared with the performance of a single-rotating axial fan, that of a counter-rotating axial fan was superior. And it is confirmed that most of the swirl flow generated by the front rotor was eliminated by the rear rotor.

• Journal of Power System Engineering
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• v.10 no.2
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• pp.36-40
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• 2006

In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Generally, the drying method is various as to the property of material and use. Rotary dryer is a good apparatus to treat them. It is the way that is to make substance transmission and heat using hot air between sludge particle and heated gas. In this paper, we developed a 3-pass rotary dryer for a design program for the 3-pass rotary dryer with various conditions. The working conditions of dryer are a raw sludge feed rate, input & output water content and operation time etc.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.11
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• pp.723-730
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• 2015

This paper investigated the noise generation mechanism of a rotary compressor using experimental method. The measurement was carried out for primary parameters which influence noise characteristics. By using STFT(short time Fourier transform), noise sources of a rotary compressor were identified and vibrating modes that increase the noise are verified. Also, it was studied that the correlation between operating speed and noise. Main factors that affect the variation of noise level were considered by the comparison of the experimental results. In addition, a dynamic characteristic of crank shaft was studied and the critical speed was analyzed.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.492-497
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• 2000

This paper focuses on the weight minimization of radial gate, as an extention of the previous work. Radial gates are commonly used to regulate the flow-rate of general purpose dams, due to its simplicity in manufacture and control. The present study identifies the optimum position of support point for 2 and 3 arm type radial gate, which guarantees the minimum weight satisfying strength constraint condition. These optimum designs are then compared with previously constructed radial gates. The results indicate that the weights of the optimized radial gates reduce by about 20%, compared to those of the conventionally designed radial gates.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.822-827
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• 2003

Experiments were done for the three dimensional unsteady flow in a counter rotating axial flow fan under stable operating condition. Flow fields in a counter rotating axial flow fan were measured at cross-sectional planes of the upstream and downstream of each rotor. Cross sectional flow patterns were investigated through the acquired data by the $45^{\circ}$ inclined hot-wire. Flow characteristics such as tip vortex, secondary flow and tip leakage flow were confirmed through axial, radial and tangential velocity vector plot. Swirl velocity, which was generated by the front rotor, was recovered in the form of static pressure rise by the rear rotor except for hub and tip regions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.15-18
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• 2012

This study is to examine general roller and rotation in using self-adhesive waterproofing sheet. Using self-adhesive waterproofing sheet is very comfortable in a waterproofing construction site. However, In mechanical construction, self-adhesive waterproofing sheet occurred that problem for using. It induce many water leakage problem. So, We make Rotation Roller for to solve the this problem, and then Comparison with Physical properties of Self-Adhesive waterproofing sheet in applied General Roller and Rotation Roller.