• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.193.1-193.1
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• 2014

This study was to investigate the electronic structure and optical properties of Na doped into NiO thin film using XPS and REELS. The films were grown by electron beam evaporation with varying the annealing temperature. The relationship between the electrical characteristics with the local structure of NiO thin films was also discussed. The x-ray photoelectron results showed that the Ni 2p spectra for all films consist of Ni 2p3/2 which indicate the presence of Ni-O bond from NiO phase and for the annealed film at temperature above $200^{\circ}C$ shows the coexist Ni oxide and Ni metal phase. The reflection electron energy loss spectroscopy spectra showed that the band gaps of the NiO thin films were slightly decreased with Na-doped into films. The Na-doped NiO showed relatively low resistivity compared to the undoped NiO thin films. In addition, the Na-doped NiO thin films deposited at room temperature showed the best properties, such as a p-type semiconducting with low electrical resistivity of $11.57{\Omega}.cm$ and high optical transmittance of ~80% in the visible light region. These results indicate that the Na doping followed by annealing process plays a crucial in enhancing the electrical and optical properties of NiO thin films. We believe that our results can be a good guide for those growing NiO thin films with the purpose of device applications, which require deposited at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.120-123
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• 2002

In this study it had an excellent optical characteristic, it followed in the creation rate and the refractive index regulation to the ease. Chalcogenide produced the $As_{45}Se_{45}Te_{10}$ thin film and the $MgF_{2}$ thin film. It measured thin film plan simulation, and the thin film has a 1 -dimensional photonic band gap. The chalcogenide $As_{45}Se_{45}Te_{10}$ thin film was measured with the fact that it has a high refractive index (2.6~2.9). The $As_{45}Se_{45}Te_{10}$ and $MgF_{2}$ thin film, have a high refractive index and a low refractive index, it used a simulation and planed period 5-pairs structure, the result was from 500nm to 800nm. It will be able to confirm the characteristic which most of the incidence light reflects, the He-Ne (632.8nm) laser was irradiated in the thin film which stabilized the thin film. $As_{45}Se_{45}Te_{10}$ (high refractive index layer: H) and $MgF_{2}$ (low refractive index layer: L) results which plans the thin film with glass/LHLHLLHLHL/air structure, 632.8nm against transmitance, increased a lot. An application possibility with the filter against a specific wave length was confirmed.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.4
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• pp.515-524
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• 1998

The purpose of this study was to evaluate the thermal properties of ceramics coated nylon fabrics by determining far infra-red emissive properties, heat storage/release and thermal insulation. Far IR emissivity and emissive power were measured for 7~ 140n at 50'C . Three types of ceramics such as cordierite with $\alpha$-alumina, a-alumina with titanium oxide and a-alumina were chosen as specimens. Cordierite with $\alpha$-alumina was chosen to treat on the fabrics due to the good emissive properties on the fabrics. Add-ons and contents of ceramics were analyzed for ceramics and/or polyurethane coated fabrics. For the physical properties, thickness and air permeability were measured. Results showed a difference in the emissive property between ceramics themselves and ceramics coated fabrics. In the ambient temperature, there was no diffenence in emissivity among the different ceramics contents. Thermography showed that when the fabric was heated with the light, surface mean temperatures of fabrics were increased as the contents of ceramics increased, and the heat storage property was confirmed. In case of same thickness and air permeability, the thermal insulation value increased as the contents of ceramics increased because of increasing heat storage and Far IR reflectivity. So there were absorption and heat storage of ceramics for Far IR from human and reflection to human between ceramics coated fabrics and human.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.96-104
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• 2008

In this study, the observation of test pieces with an optical microscope was carried out after fabricating 4 groups of standard lacquer, in order to inquire into the ancient lacquering techniques. Group I had transparent reddish brown color, and the part of layer was indefinite, and the layer polished was easily distinguished. Group II had mostly transparent yellowish brown color, and it was possibility distinguished the layers when they were varnished with mixed lacquer after prime coating, and when they were varnished with lacquer as the prime coating. Group III set up membrane in the hardening process of the lacquer, and the lacquer and the unsaturated fatty acid of internal part was dried, so the top layer and the lacquer layer were separated and observed. Group IV: When the lacquer coat film of Group IV test pieces were observed in polarized light, the ferrous components were seen as the black and red color were mixed, and the silica crystals of silty soil were distinguished by reflection of lights. And the colors were distinguished as the lacquer layer of ruddle had red color, and the mixed lacquer of reddish lacquer and ruddle had the deep red color at the top and the bottom, but the middle part had the bright red color.

• Journal of Pharmaceutical Investigation
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• v.35 no.6
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• pp.411-416
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• 2005

The aim of the present work was to prepare the nanosuspension of inorganic pigment which shows light reflection and scattering as efficient sunscreen. The zinc oxide (ZnO) was chosen as an inorganic pigment, and high pressure homogenizer and bead mill have been used for the preparation of nanosuspension. The ZnO nanosuspensions were characterized by particle size, in vitro sun protection factor (SPF) and UV transmittance. ZnO nanosuspension prepared by bead mill showed the average diameter of $119{\pm}4\;nm$, resulting in the high value of SPF $(28.74{\pm}2.06,\;n=20)$, while that prepared by high pressure homogenizer showed the average diameter of $751{\pm}32\;nm$ with the relative lower value of SPF $(21.38{\pm}1.94\;n=20)$. In addition, the film of ZnO nanosuspension prepared by bead mill was showed a high visible ray (VIS) transmittance, indicating a high transparency. In conclusion, a physically stable ZnO nanosuspension in cyclomethicone was successfully prepared using bead mill for the suitable sunscreen preparations.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.2
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• pp.29-32
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• 2013

The surface roughness and reflectivity of electroless-plated Sn-3.5 wt%Ag on a LED (light emitting diode) lead frame were investigated. Cu electroplating was carried out prior to electroless plating of Sn-3.5Ag to improve the reflectivity of the Sn-3.5Ag deposit. In order to investigate the effect of stirring speed and temperature of the plating solution, surface roughness and reflectivity was measured. The experimental results revealed that the thickness of the deposit layer increased with stirring speed and temperature of the plating solution. Stirring speed is increased from 100 to 300 rpm, the surface roughness was reduced from 0.513 to 0.266 ${\mu}m$, and the reflectivity increased from 1.67 to 1.84 GAM. As temperature of the plating solution increased from 25 to $45^{\circ}C$, the surface roughness reduced from 0.507 to 0.350 ${\mu}m$, and the reflectivity increased from 1.68 to 1.84 GAM.

• Journal of the Korean earth science society
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• v.26 no.7
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• pp.714-724
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• 2005

The East Sea, a semi-enclosed marginal sea with shallow straits in the northwest Pacific, is marked by the nearly geographic isolation and the low sea surface salinity during the last glacial maximum (LGM). The East Sea might have the only connection to the open ocean through the Korea Strait with a sill depth of 130 m, allowing the paleo-Tsushima Water to enter the sea during the LGM. The low paleosalinity associated with abnormally light $\delta^{18}O$ values of planktonic foraminifera is interpreted to have resulted from river discharge and precipitation. Nevertheless, two LGM features in the East Sea are disputable. This study attempts to estimate volume transport of the paleo-Tsushima Water via the Korea Strait and further examines its effect on the low sea surface salinity (SSS) during the lowest sea level of the LGM. The East Sea was not completely isolated, but partially linked to the northern East China Sea through the Korea Strait during the LGM. The volume transport of the paleo-Tsushima Water during the LGM is calculated approximately$(0.5\~2.1)\times10^{12}m^3/yr$ on the basis of the selected seismic reflection profiles along with bathymetry and current data. The annual influx of the paleo-Tsushima Water is low, compared to the 100 m-thick surface water volume $(about\;79.75\times10^{12}m^3)$ in the East Sea. The paleo-Tsushima Water influx might have changed the surface water properties within a geologically short time, potentially decreasing sea surface salinity. However, the effect of volume transport on the low sea surface salinity essentially depends on freshwater amounts within the paleo-Tsushima Water and excessive evaporation during the glacial lowstands of sea level. Even though the paleo-Tsushima Water is assumed to have been entirely freshwater at that time period, it would annually reduce only about 1‰ of salinity in the surface water of the East Sea. Thus, the paleo-Tsushima Water influx itself might not be large enough to significantly reduce the paleosalinity of about 100 m-thick surface layer during the LGM. This further suggests contribution of additional river discharges from nearby fluvial systems (e.g. the Amur River) to freshen the surface water.

• Korean Journal of Materials Research
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• v.23 no.4
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• pp.215-218
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• 2013

Vanadium dioxide ($VO_2$) is an attractive material for smart window applications where the transmittance of light can be automatically modulated from a transparent state to an opaque state at the critical temperature of ${\sim}68^{\circ}C$. Meanwhile, F : $SnO_2$ (F-doped $SnO_2$, FTO) glass is a transparent conductive oxide material that is widely used in solar-energy-related applications because of its excellent optical and electrical properties. Relatively high transmittance and low emissivity have been obtained for FTO-coated glasses. Tunable transmittance corresponding to ambient temperature and low emissivity can be expected from $VO_2$ films deposited onto FTO glasses. In this study, FTO glasses were applied for the deposition of $VO_2$ thin films by pulsed DC magnetron sputtering. $VO_2$ thin films were also deposited on a Pyrex substrate for comparison. To decrease the phase transition temperature of $VO_2$, tungsten-doped $VO_2$ films were also deposited onto FTO glasses. The visible transmittance of $VO_2$/FTO was higher than that of $VO_2$/pyrex due to the increased crystallinity of the $VO_2$ thin film deposited on FTO and decreased interface reflection. Although the solar transmittance modulation of $VO_2$/FTO was lower than that of $VO_2$/pyrex, room temperature solar transmittance of $VO_2$/FTO was lower than that of $VO_2$/pyrex, which is advantageous for reflecting solar heat energy in summer.

• Journal of the Korean Wood Science and Technology
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• v.27 no.3
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• pp.23-30
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• 1999

have been many studies to analyze the behavior of metal plate connector that most widely used to connect light frame wood trusses. Finite element method{FEM) was one of the methods for those studies. FEM using linear model may well be applicable to predict the initial slope of load-displacement curve for metal plate connection. However, displacement may be overestimated above experimental results with the increase of load. Therefore, linear model cannot be used for the nonlinear behavior part. To predict real behavior more exactly, nonlinear term was included to FEM model in this study. It was found out that EA and AA mode showed the high agreement between predicted results and experimental ones. However, EE and AE mode showed a little difference between predicted results and experimental ones in nonlinear part. This results might be caused by insufficient reflection of the slip effect. Consequently, the effect of slip shall be considered to approve the accuracy of nonlinear analysis for the behavior of metal plate connection.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.65-65
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• 2007

Microstructure and surface roughness of the sensing materials should be improved to use them in advanced sensor applications because the uneven surface roughness degrades the light reflection, pattern resolution, and devices performance. Chemical mechanical polishing (CMP) processing was selected for improving the surface roughness of $CeO_2$ which is one of the well known materials for the oxygen gas sensors. Surface roughness and removal rate of spin coated $CeO_2$ thin films were examined with a change of CMP process parameters such as down force and table speed. The optimized process condition, reflected by the surface roughness with the hillock-free surface as well as the excellent removal rate with the good uniformity, was obtained. The effects of the improved surface roughness on the sensing property of $CeO_2$ thin films were also confirmed. The improved sensitivity of $CeO_2$ thin films for oxygen sensors were obtained after CMP process by the improved surface characteristics. Therefore, we conclude that sensing property of $CeO_2$ thin film is strongly dependent on the surface roughness of $CeO_2$ thin films by using CMP process.