• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.45-49
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• 2010

The contamination(stain phenomenon) of natural marble(sipeol, bianko) of art wall of on-site interior finishing system and wall of elevator hall has occurred. The bottom of the art wall of stone junction tile has defects as cracks. To solve these problems, our research team developed eco-friendly complex stone panel(stone 4T + cement board 6T) and high-frequency hot-melt construction method that can construct in winter.

• Transactions of Materials Processing
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• v.20 no.6
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• pp.432-438
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• 2011

A method for estimating the shear spinnability is suggested, and it was applied to sheets of Ti-6Al-4V alloy for estimation of shear spinnability at hot working temperature. The effective working temperature was $850^{\circ}C$ or above. The hot spinning operation was carried out in two steps of shear spinning. The reduction of thickness at the first step was 50% and 45% at the second, and the overall reduction of thickness was 72.4%. The cone spinning process could produce a uniform wall thickness with only a few percent tolerance, proving itself appropriate for making cones of Ti-6Al-4V alloy with uniform wall thickness.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.158-162
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• 2001

SrS:Ce thin films for blue EL devices are prepared by Hot Wall Method and their crystallographic and optical characteristics are investigated by various methods. Deposition rates are decreased with substrate temperature, but increased with SrS cell temperature. The crystallographic characteristics are strongly affected by deposition rates. The peak of photoluminescence are found ar 470 and 540nm.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.1
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• pp.9-18
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• 2003

An experimental study was performed to investigate the turbulence intermittency measuring methods across the boundary layer in the transition region. A single type hot-wire probe was used to measure instantaneous streamwise velocities in laminar, transitional and turbulent boundary layer To estimate wall shear stresses on the flat plate, near wall mean velocities are applied to the principle of CPM. Distribution of intermittency factor is obtained by dual-slope method and compared to the results of four methods,$\'{u},\;\{U}$, TERA and M-TERA method. In these methods, M-TERA shows a good agreement in the near wall region. However, the result of M-TERA method shows that intermittency factor is underestimated in the outer part and outside of the boundary layer and the dimensional constant of M-TERA method should be changed appropriately depending on measuring point.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.267-270
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• 2004

A silver indium sulfide($AgInS_2$) epilayer was grown by the hot wall epitaxy method, which has not been reported in the literature. The grown $AgInS_2$ epilayer has found to be a chalcopyrite structure and evaluated to be high qualify crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks. are ascribed to the band-to-band transition. The valence band splitting of $AgInS_2$ was investigated by means of the photocurrent measurement. The crystal field splitting, $\ddot{A}cr$, and the spin orbit splitting, $\ddot{A}so$, have been obtained to be 0.150 eV and 0.009 eV at 10 K, respectively. And, the energy band gap at room temperature has been determined to be 1.868 eV. Also, the temperature dependence of the energy band gap, $E_g(T)$, was determined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.143-144
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• 2008

Single crystal $ZnIn_2S_4$ layers were grown on a thoroughly etched semi-insulating GaAs(100) substrate at $450^{\circ}C$ with the hot wall epitaxy (HWE) system by evaporating the polycrystal source of $ZnIn_2S_4$ at $610^{\circ}C$ prepared from horizontal electric furnace. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of single crystal $ZnIn_2S_4$ thin films measured with Hall effect by van der Pauw method are $8.51\times10^{17}$ electron/$cm^{-3}$, 291 $cm^2$/v-s at 293 K, respectively.

• Journal of the Korean Vacuum Society
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• v.8 no.3B
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• pp.302-307
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• 1999

We have grown a high quality ZnSe(100) epilayer on the GaAs(100) substrate by hot-wall epitaxy method. The FWHM value from double-crystal x-ray diffraction rocking curve and growth rate of the ZnSe epilayer grown under the optimal growth conditions were 195 arcsec and 0.03 $\mu \textrm m$/min, respectively. The $I_2^U$ and $I_2^L$ peaks, which split by strain due to lattice mismatch between substrate and epilayer, were measured from the photoluminescence experiment. And we found that the residual impurities in ZnSe epilayer were concerned with Al or CI elements from the calculated binding energy of donor impurity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.92-96
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• 2002

A silver indium sulfide $(AgInS_{2})$ epilayer was grown by the hot wall epitaxy method, which has not been reported in the literature. The grown $AgInS_{2}$ epilayer has found to be a chalcopyrite structure and evaluated to be high quality crystal. From the photocurrent measurement in the temperature range from 30 K to 300 K, the two peaks of A and B were only observed, whereas the three peaks of A, B, and C were seen in the PC spectrum of 10 K. These peaks are ascribed to the band-ta-band transition. The valence band splitting of $AgInS_{2}$ was investigated by means of the photocurrent measurement. The crystal field splitting, $\Delta_{cr}$, and the spin orbit splitting, $\Delta_{so.}$ have been obtained to be 0.150 eV and 0.009 eV at 10 K, respectively. And, the energy band gap at room temperature has been determined to be 1.868 eV. Also, the temperature dependence of the energy band gap, $E_{g}(T)$, was determined.

• Journal of Powder Materials
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• v.9 no.3
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• pp.153-160
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• 2002

A nitrogen gas atomized aluminum powder was consolidated by powder-in sheath rolling method. A pure aluminum tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. The aluminum tube filled with the aluminum powder, first, was cold-rolled to the thickness of 6mm for performing, and then consolidated by the cold rolling and/or subsequent hot rolling at 360, 460 and $560^{\circ}C$. The aluminum powder compact fabricated by the sheath rolling showed high relative density more than 0.96 at any rolling conditions. The 0.2% proof stress increased with increasing hot rolling reduction and hot rolling temperature. Tensile strength was hardly affected by change in the hot rolling reduction, whereas it decreased with increasing hot rolling temperature. The powder compact showed the large elongation when cold rolling or hot rolling reduction was large. It was found that the sheath rolling was an effective method for consolidation of aluminum powder.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.149-149
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• 2016

Ceramic is widely known material due to its outstanding mechanical property. Besides, Zirconia(ZrO2) has a low thermal conductivity so it is advantage in a heat insulation. Because of these superior properties, ZrO2 is attracted to many fields using ultra high temperature for example vehicle engines, aerospace industry, turbine, nuclear system and so on. However brittle fracture is a disadvantage of the ZrO2. In order to overcome this problem, we can make the ceramic materials to the forms of ceramic nanoparticles, ceramic nanowhiskers and these forms can be used to an agent of composite materials. In this work, we selected Au catalyzed Vapor-Liquid-Solid mechanism to synthesize ZrO2 nanowhiskers. The ZrO2 whiskers are grown through Hot-wall Chemical Vapor Deposition(Hot wall CVD) using ZrCl4 as a powder source and Au film as a catalyst. This Hot wall CVD method is known to comparatively cost effective. The synthesis condition is a temperature of $1100^{\circ}C$, a pressure of 760torr(1atm) and carrier gas(Ar) flow of 500sccm. To observe the morphology of ZrO2 scanning electron microscopy is used and to identify the crystal structure x-ray diffraction is used.