• 대한기계학회논문집B
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• 제23권6호
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• pp.753-760
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• 1999

Experiments were conducted to investigate the effect of the initial turbulent intensity on the flow and heat transfer characteristics for a two-dimensional impinging jet. A square rod was installed at the nozzle exit to increase initial turbulent intensity. A hot wire probe and thermochromic liquid crystal technique were used to measure the turbulent intensity and the surface temperature. All measurements were made over a range of nozzle-to-plate distance from 1 to 10 at Re=20,000. When the rod is not installed, the maximum stagnation point Nusselt number is occurred at H/B=9. A higher initial turbulent intensity enhanced the heat transfer on the surface. A correlation between stagnation point Nusselt number and turbulent intensity are presented.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1995년도 추계학술발표회논문집(2)
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• pp.574-579
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• 1995

Saturated boiling heat transfer experiment in a hemispherical narrow space is conducted using Freon-113 to investigate an additional heat removal capability through a hypothetical gap between lower head and degraded core. The narrow space of 1mm consists of a 124mm diameter heated stainless steel hemisphere and a glass outer vessel. Within the hemispherical narrow space large coalesced bubbles are produced and these bubbles rise in random direction, causing liquid flow in from the opposite side to fill the region. Such flow in random direction makes the flow field in the narrow space very chaotic and thus enhance heat transfer. The heat transfer coefficient is higher at lower angle and at higher heat flux. The present study shows that the liquid from upper region can effectively penetrate into the gap and augment the heat removal capability through tile gap.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.178-179
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• 2021

Comparing the absorption volume of test pieces immersed over time in room temperature moisture with weight, WF absorbed about 40% more than PLAIN, and PLAIN stopped absorbing after 10 minutes, but WF continued to absorb. It is thought that the woven fabric layer of the core material continued to absorb moisture. In the heat transfer test, the test piece to which only WF was applied had a temperature difference of about 2℃ compared to PLAIN, and when the insulating liquid was sprayed, there was a difference in heat transfer properties of up to 5℃. This is judged to have low heat transfer properties of the basic woven fabric, but the heat insulating liquid also further reduces heat transfer properties.

• Journal of Mechanical Science and Technology
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• 제19권8호
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• pp.1649-1661
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• 2005

We consider. a horizontal static liquid layer on a planar solid boundary. The layer is evaporating when the plate is heated. Vapor recoil and thermo-capillary are discussed along with the effect of mass loss and vapor convection due to evaporating liquid and non-equilibrium thermodynamic effects. These coupled systems of equations are reduced to a single evolution equation for the local thickness of the liquid layer by using a long-wave asymptotics. The partial differential equation is solved numerically.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.850-856
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• 2009

A new type bi-directional damper using a tuned liquid column damper(TLCD) and a tuned sloshing damper(TSD) is introduced in this study. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with one damper. One of objectives of this study is to derive analytical dynamics to investigate coupled effects due to TLCD and TSD. Another objective is to address the effect of coupled control force due to TLCD and TSD on the dynamic characteristic of the damper based on analytical dynamics. Shaking table test is undertaken to experimentally grasp dynamic characteristics of the damper under white noise excitation. Its dynamic characteristic is expressed by the transfer function from the shaking table acceleration to the control force generated from the damper. Finally, its design parameters are identified based on the coupled dynamics, which include the mass ratio of horizontal liquid column to total liquid for a TLCD, the participation factor of the fundamental liquid sloshing for a TSD and damping ratio for both cases.

• Journal of Advanced Marine Engineering and Technology
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• 제30권6호
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• pp.702-708
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• 2006

This study shows the experimental characteristics of the double pipe inserted liquid pipe with small diameter in the gas pipe with large diameter for circulating of a liquid of high temperature, pressure and a gas of low temperature, pressure at the same time. So the functions of pipe and pipe's expansion and heat transfer are presented simultaneously. In the result, the temperature of gas refrigerant at the inlet of compressor increased about $5^{\circ}C$ by the heat transfer with liquid refrigerant in case of the double pipe. And liquid gas refrigerant which the temperature at the inlet of evaporator decreased about $3^{\circ}C$ comparing with the existing type flows into an evaporator COP of the double pipe increased about $7{\sim}10%$ comparing with that of the conventional pipe. And the noise of the double pipe at capillary tube is less than that of the conventional type about 3dB. Consequently. it is convinced the superiority of the double pipe in the heat loss and soundproofing aspect.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.473-473
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• 2011

In recent years, organic thin film transistors OTFTs based on conductive-conjugated molecules have received significant attention. We report a fabrication of organic single crystal nanowires that made on Si substrates by liquid bridge-mediated nanotransfer molding (LB-nTM) with polyurethane acrylate (PUA) mold. LB-nTM is based on the direct transfer of various materials from a stamp to a substrate via a liquid bridge between them. In liquid bridge-transfer process, the liquid layer serves as an adhesion layer to provide good conformal contact and form covalent bonding between the organic single crystal nanowire and the Si substrate. Pentacene is the most promising organic semiconductors. However pentacene has insolubility in organic solvents so pentacene OTFTs can be achieved with vacuum evaporation system. However 6, 13-bis (triisopropylsilylethynyl) (TIPS) pentacene has high solubility in organic solvent that reported by Anthony et al. Furthermore, the substituted rings in TIPS-pentacene interrupt the herringbone packing, which leads to cofacial ${\pi}-{\pi}$ stacking. The patterned TIPS-Pentacene single crystal nanowires have been investigated by Atomic force microscopy (AFM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and electrical properties.

• 한국소음진동공학회논문집
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• 제20권3호
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• pp.287-295
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• 2010

This study deals with the design of a bi-directional damper using a tuned liquid damper(TLD) and a tuned liquid column damper(TLCD) for a SDOF building. Two dampers are usually needed to reduce wind-induced responses of tall buildings since they are along and across wind ones. The proposed damper has the advantage of controlling both responses with a single damper. The damper used in this study behaves as both a TLCD in a specific translational direction and a TLD in the other orthogonal direction. This paper presents experimental verification to confirm its control performance. First, shaking table test is carried out to investigate reducing responses by the damper. Control performance of the damper is expressed by the transfer function from shaking table accelerations to SDOF building ones. Testing results show that the damper reduced bi-directional responses of a SDOF building. Also, it reduced torsion responses.

• International Journal of Air-Conditioning and Refrigeration
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• 제16권2호
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• pp.64-69
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• 2008

Electronic and telecommunication industries are constantly striving towards miniaturization of electronic devices. Miniaturization of chips creates extra space on PCBs that can be populated with additional components, which decreases the heat transfer surface area and generates very high heat flux. Even though an air-cooling technology for telecommunication equipment has been developed in accordance with rapid growth in electrical industry, it is confronted with the limitation of cooling capacity due to the rapid increase of heat density. In this study, liquid-cooling heat exchangers were designed and tested by varying geometry and operating conditions. In addition, air-cooling heat exchangers were tested to provide performance data for the comparison with the liquid-cooling heat exchangers. The liquid-cooling heat exchangers had twelve rectangular channels with different flow paths of 1, 2, and 12. Silicon rubber heaters were used to control the heat load to the heat exchangers. Heat input ranged from 293 to 800W, and inlet temperatures of working fluid varied from 15 to $27^{\circ}C$. The heat transfer coefficients were strongly affected by flow conditions. All liquid-cooling heat exchangers showed higher cooling performance than the air-cooling heat exchanger. The heat exchanger with 2-paths could provide more controllability on the maximum temperature than the others.

• 대한설비공학회지:설비저널
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• 제8권1호
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• pp.10-13
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• 1979

The study for bubbling phenomena to influence heat transfer in gas - liquid contactors. The sparged contactor is gaining importance for gas-liquid chemical reactions. In this paper, correlations between Reynolds number and heat transfer coefficient were studied and experimental expressions were also obtained over broth of areas, namely, laminar area and turbulent area respectively.