• Journal of the Korean Society for Heat Treatment
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• v.17 no.5
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• pp.293-298
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• 2004

For the application of heat sink device, the green sheets of powder of W-XCu and Mo-XCu composites were fabricated by tape casting technique. The mixing ratio of powder and binder was 6:4. The green sheet was shrinked up to 10~20% after sintering and the maximum relative density was above 95%. Thermal conductivity and Thermal expansion systematically increased with increasing Cu contents. The maximum thermal conductivity of W-20wt.%Cu was about 206[W/mK].

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1060-1069
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• 2005

Silencers are engineering devices that are designed to attenuate sound waves propagating in a flowing medium. The muffler type silencer has a series of chambers in parallel or series utilizing the reflection and expansion characteristics of the expansion chambers, sidetubes, branch resonators, and tailpipes to attenuate the sound. To Improve the performance of industrial blower silencer of muffler type which is employed in petrochemical plant, this paper seeks its optimal arrangement of buffs by experimental method and suggests optimal arrangement of buffs. Experimental results show that the optimal one suggested can reduce the noise level as much as 14 dB (or 18 dB(A)) in the laboratory and as much as 4 dB(A) compared to that of the existing silencer on the ground.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.1 no.1
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• pp.81-86
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• 1989

Herein the surge-heave-pitch motion of a ship has been analyzed within the framework of linear potential theory. The ship is assumed slender weakly moored along the centerline of a rectangular harbor with constant depth and straight coastline. The method of matched asymptotic expansion is us-ed to obtain the leading-order solution. The ship and harbor responses to incident long waves can be re-presented in terms of Green's function, which is the solution of the Helmholtz equation satisfying necessary boundary conditions. Numerical results clearly indicate the importance of the surge motion.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.525-528
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• 1988

In this paper, a new multi-output logic minimization algorithm is presented. A base minterm is selected in the given function and the prime implicant is obtained by expanding it in the order of the expansion set that is decided by heuristic method. Input-oriented expansion procedure is used to reduce fan-in and fan-out number. To show the effectiveness of this algorithm, comparative run time with other minimization algorithm is given.

• Proceedings of the KSR Conference
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• 1999.05a
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• pp.442-449
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• 1999

Due to temperature variations, considerable longitudinal rail forces and displacements may develop in continuous welded rail(CWR) track on long-span bridges or viaducts. Excessive relative displacements between sleepers and ballast bed may disturb the stable position of the track in the ballast which results in a lower frictional resistance. Generally, these problems are solved by installing rail expansion devices. However the application of expansion devices in high-speed tracks on existing bridges, as a means to prevent excessive longitudinal displacements and forces, is not attractive method due to comfort, safety and maintenance aspects. An alternative and very effective solution is possibly the use of so-called zero longitudinal restraint(ZLR) fastenings over some length of the track. The calculations, carried out in this respect, show a considerable reduction of track displacements, track forces, and the relative sleeper/ballast displacements. This reduction depends on the length over which these fastenings are installed. In this paper calculations of the longitudinal displacments and forces in a CWR track and substructure resulting from thermal, mechanical and kinematical loads were carried out using the FEM analysis program LUSAS

• Journal of the East Asian Society of Dietary Life
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• v.10 no.1
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• pp.71-76
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• 2000

This study was carried out in order to investigated the degree of expansion, textural and sensory characteristics of Yukwa made from various cultivars of waxy rice, With 5 varieties of waxy rice and a nonwaxy rice, Yukwa were prepared by the standardized method that had been established optimum preparation conditions. Yukwa made from Shinsunchalbyeo and Whasunchal showed lower degree of expansion than Hangangchalbyeo and IR 29, but showed higher crispness and softer texture among tested waxy rice cultivars. Sensory characteristics of these cultivars showed high score in flavor, crispness and preference. Whasunchalbyeo and Shinsunchalbyeo were appropriate varieties for Yukwa preparation and they were both short grain in length/width. Whasunchalbyeo has the highest score of water uptake and reducing sugar content in Key word.

• Nuclear Engineering and Technology
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• v.30 no.4
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• pp.377-385
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• 1998

Many nuclear power plants have experienced unscheduled shutdown due to the leakage of steam generator tubes. The leakages are normally due to the crack, possibly stress corrosion cracking (SCC) near the tube expansion at the top of tubesheet or at the tangential point of the row-1 U-bend region. The conventional eddy current technique, which makes use of a differential bobbin coil, has been found to be inadequate for the early detection of SCC. During the in-service inspection, therefore, it is a general practice that the rotating pancake coil (RPC) is used for detecting the cracks. Even in using RPC, however, it is difficult to determine the depth of the cracks quantitatively. This paper attempts to determine the detectability and sizing ability of RPC technique for axial or circumferential cracks at the tube expansion region. The simulated cracks with various dimensions were fabricated by electro-discharge machining (EDM) method. Experimental results are discussed with theoretical calculations.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.116-119
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• 2007

The application of light weight materials, such as aluminum alloy, has been limited due of their poor formability. Especially, aluminum alloy tube has limited expansion capability at most 15% at room temperature. New manufacturing process, called hot air forming, is introduced to apply aluminum tube to the automotive suspension components which have complex shape and require high expansion ratio about 40%. The process is carried out at the elevated temperature above $500^{\circ}C$, so numerous material properties and process parameters related to the high temperature should be investigated and determined to get a sound product. In this study, the effect of thermal properties and forming parameters such as the temperature of tool, axial feeding and gas pressure are analyzed by using explicit finite element method.

• Journal of KSNVE
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• v.3 no.3
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• pp.271-278
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• 1993

Acoustic characteristics of silencer system are affected by various geometric parameters such as cross sectional geometry, size of chamber, and location of inlet-outlet port. It is impossible to obtain exact solutions of the equations of acoustic wave propagation except few simple cases. So, we resort to numerical techniques to analyze performance of acoustic system. In this work, finite element formulation has been obtained to predict transmission loss of an arbitrary 3-dimensional muffler in the presence of mean flow of low mach number. The effect of the degree of the ellipticity of expansion chambers on the transmission loss has been studied using the resulting finite element equation.

• Journal of Korean Public Health Nursing
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• v.18 no.1
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• pp.50-60
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• 2004

This is a Phenomenological study to describe the experience of nursing students on blind persons. Report and individual interviews were conducted on subjective experience of 5 nursing students. Data were analyzed through Giorgi's method in which meaningful statements. The results were from significant statements on reports and interview. These were clustered into 17 theme and 4 central meaning. Nursing Students started practice with prejudice, fear, and expectation at the same time. They also experienced complicated feelings (expansion of consciousness, growth of self, expansion of emotion, true presence)for the blind person. Make a situational structural description from theme and central meaning. Make a general structural description from situational structural description.