• International Journal of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.39-44
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• 2018

Wideness variation technique is compounded the smooth diffusivity-vibration status of the fulgurate-space realization level (FSRL) on the wideness realization morph. The realization level condition by the wideness realization morph system is associated with the diffusivity-vibration system. As to search a position of the dot situation, we are acquired of the wideness value with constructed-point point by the diffusivity upper structure. The concept of realization level is composed the reference of fulgurate-space level for variation signal by the wideness vibration morph. Further displaying a smooth variation of the FSRL of the maximum-minimum in terms of the diffusivity-vibration morph, and wideness position vibration that was the a wideness value of the far variation of the $Wid-rm-FA-{\alpha}_{MAX-MIN}$ with $23.24{\pm}3.37units$, that was the a wideness value of the convenient variation of the $Wid-rm-CO-{\alpha}_{MAX-MIN}$ with $7.83{\pm}1.32units$, that was the a wideness value of the flank variation of the $Wid-rm-FL-{\alpha}_{MAX-MIN}$ with $2.99{\pm}0.51units$, that was the a wideness value of the vicinage variation of the $Wid-rm-VI-{\alpha}_{MAX-MIN}$ with $0.51{\pm}(-0.01)units$. The diffusivity vibration will be to evaluate at the smooth ability of the diffusivity-vibration morph with constructed-point by the wideness realization level on the FSRL that is displayed the fulgurate-space morph by the realization level system. Diffusivity realization system will be possible to control of a morph by the special signal and to use a wideness data of diffusivity vibration level.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1326-1331
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• 2004

In this paper, we have investigated thermal properties and Impurities content of specimens showing by changing the content of carbon black that is semiconductive materials for underground power transmission. Specimens were made of sheet form with the three of existing resins and the nine of specimens for measurement. Impurities content of specimens was measured by ICPAES(Inductively Coupled Plasma Atomic Emission Spectrometer). Heat capacity(ΔH) and melting temperature(Tm) were measured by DSC(Differential Scanning Calorimetry). The ranges of measurement temperature were from $0^{\circ}C$ to 20$0^{\circ}C$, and heating temperature was 4$^{\circ}C$/min. And then thermal diffusivity was measured by LFA 447. The measurement temperature was $25^{\circ}C$. Impurities content was highly measured according to increasing the content of carbon black from ICPAES results. And heat capacity and melting temperature from the DSC results were simultaneously decreased according to increasing the content of carbon black, while thermal diffusivity was increased according to increasing the content of carbon black. Because ionic impurities of carbon black containg Fe, Co, Mn, Al, and Zn were rapidly increasing kinetic energy by vibration of ionic impurities through the applied heat energy.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.8
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• pp.759-763
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• 2015

The laser machining process has been proposed as an advanced process for the selective fabrication of electrodes without a mask. In this study, we adapt laser machining to metals that have different thermal properties. Based on the results, the metals exhibit a different surface morphology, heat-affected zone (HAZ), and a recast layer around the machined surface according to their thermal conductivity, boiling point, and thermal diffusivity. Then, we apply ultrasonic-assisted laser machining to remove the recast layer. The ultrasonic-assisted laser machining exhibits a better surface quality in metals with higher diffusivity than those having lower diffusivity.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.149-153
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• 2005

We have investigated thermal properties showed by changing the content of carbon black which is the component parts of semiconductive shield in underground power transmission cable. Specimens were made of sheet with the nine of those for measurement. Heat capacity (${\Delta}$H), glass transition temperature (Tg) and melting temperature (Tm) were measured by DSC (Differential Scanning Calorimetry). The ranges of measurement temperature were from -100($^{\circ}C$) to 100($^{\circ}C$), and heating rate was 4($^{\circ}C$/min). And then thermal diffusivity was measured by LFA 447. The dimension of measurement temperature was 25[$^{\circ}C$]. Glass transition temperature of specimens was showed near -25[$^{\circ}C$] and the heat capacity and the melting temperature from the DSC results were simultaneously decreased according to increasing the content of carbon black, while thermal diffusivity was increased according to increasing the content of carbon black. Because ionic impurities of carbon black having Fe, Co, Mn, Al and Zn are rapidly passed kinetic energy increasing the number of times breaking during the unit time with the near particles according to increasing vibration of particles by the applied heat energy.

• Journal of the Korean Society of Safety
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• v.13 no.3
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• pp.112-118
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• 1998

This work has been carried out to study the mixing characteristics of solid in vibrating feeder for stable operations of fluidized bed combustion. The system consisted of two particles such that fine particles were located on the top of the coarse particles before vibratory mixing had started. Effect of particle size, particle densities, vibration amplitude and vibration frequency were experimentally obtained. Also, a diffusion model was applied in interpreting the experimental results. From these results, the following empirical equation for the diffusivity was obtained. $0.87{(\frac{d_c}{d_f})}^{0.73}\;{(\frac{\rho_f}{\rho_c})}^{0.53}(A^2f)$.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1223-1229
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• 2007

Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the leading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

• Journal of Korea Foundry Society
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• v.22 no.3
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• pp.137-143
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• 2002

Silica sand, zircon sand, and steel shots were used as mold packing materials in lost foam casting of the aluminum alloy bar. Vibration acceleration in three directions and temperatures in the casting and mold were measured, and packing and cooling characteristics of these materials were investigated. Packing densities increased with increase in vibration magnitude and time, and were $1.41{\sim}1.49g/cm^2$ for silica sand, $2.54{\sim}2.86g/cm^2$ for zircon sand, and $3.92{\sim}4.52g/cm^2$ for steel shots. Sound castings were obtained only without evacuation of the flask during pouring. Solidification time became faster in order of silica sand, zircon sand and steel shot packing because steel shot has the highest cooling capacity of them. Solidification time of steel shot packing was shortened to about 1/2 of silica sand packing. Cooling capacity of sand mold was generally evaluated by heat diffusivity of the mold, however could be simply evaluated with specific heat per unit volume of the packing material in lost foam casting.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.196-199
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• 2005

Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the loading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.