• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.421-426
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• 2012

The effect of synthesis conditions such as various organic material and composition of organic-inorganic material in ozone resistance and surface characteristic of ultraviolet cured organic-inorganic hybrid coating film has been investigated. Organic-inorganic hybrid coating solution was prepared using tetraethoxysilane (TEOS), silane coupling agent methacryloyloxypropyltrimethoxysilane (MPTMS), 2,2,2-trifluoroethylmethacrylate, and various organic materials with acrylate group, bar-coated on substrates using applicator and densified by UV-curing. It was found that ozone resistance and surface hardness of the coating film was increased with contents of TEOS. It was also found that ozone resistance of coating film was increased with contents of 2,2,2-trifluoroethylmethacrylate. On the other hand, surface hardness was decreased with increase of 2,2,2-trifluoroethylmethacrylate. In addition, Surface hardness of coating film was increased with the addition of aliphatic urethane acrylate. It was also found that the transmittance of coating films was not influenced by content of TEOS and 2,2,2-trifluoroethylmethacrylate. In addition, the coating film exhibited high transmittance of above 90%.

• Elastomers and Composites
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• v.53 no.3
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• pp.175-180
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• 2018

Solution-styrene-butadiene rubber (SSBR) composites were manufactured using four kinds of fillers: silica-silane coated carbon black (SC-CB) hybrid, starch-SC-CB hybrid, pure silica, and pure starch. The influence of filler type on the mechanical properties of the rubber matrix was studied in this work. SC-CB was prepared by silane-graft-coating using vinyl triethoxy silane and carbon black, which enhanced the dispersion effect between the rubber matrix and the filler, and improved the mechanical properties of the compounds. The morphology of the composites was observed by field-emission scanning electron microscopy (FE-SEM). The thermal decomposition behavior of the composites was determined by thermogravimetric analysis (TGA), and the crosslinking behavior of the composites was tested using a rubber process analyzer (RPA). The hardness, tensile strength, swelling ratio, and gas transmittance rate of the composites were evaluated according to ASTM. The test results revealed that with the addition of SC-CB, the hybrid fillers, especially those blended with silica, showed a better reinforcement effect, the highest hardness and tensile strength, and stable thermal decomposition behavior. This implies that the silica-SC-CB hybrid filler has a notable mechanical reinforcement effect on the SSBR matrix. Because of self-crosslinking during its synthesis, the starch-SC-CB hybrid filler produced the most dense matrix, which improved the anti-gas transmittance property. The composites with the hybrid fillers had better anti-swelling properties as compared to the neat SSBR composite, which was due to the hydrophilicity of silica and starch.

• Korean Journal of Crystallography
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• v.7 no.1
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• pp.30-35
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• 1996

Calcite(CaCO3) single crystals were grown hydrothermally and transmittance of as grown crystals was measured. Instead of platinium, teflon was lined onto the wall of autoclave to prevent the corrosion of autoclave wall by acidic NH4Cl solution. Spontaneous nucleation and growth of calcite crystal on teflon was reduced considerably by addition of NaCl and /or CH3COOH and applying low temperature gradient. When the temperature gradient exceeded to a few degrees from the critical temperature gradient(6-7℃), spontaneous nucleation and growth was rapidly increased in any hydrothermal solutions. Precise temperature control is thought to be the most important factor for the growth of calcite single crystal by hydrothermal technique. As grown calcite single crytal showed high transmittance compared to natural one by UV-visible analysis.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.73-77
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• 2005

In this study, we investigated response characteristics of liquid crystal display (LCD) with different operating mode of nematic liquid crystals (NLCs) such as 45 $^{circ} twisted nematic (TN), 67.3 $^{circ} TN and electrical controlled birefringence (ECB) on the rubbed polyimide (PI) surface with side chains. The pretilt angles generated on polyimide surfaces of the three kinds of LCD operating modes were about 12 $^{circ} that was higher than those of conventional TN-LCOs. Also, the Electro-optical (EO) performance of these LCOs showed stable condition. Low transmittance of the 45 $^{circ} TN and 67.3 $^{circ} TN cell on the rubbed PI surface were measured by using low cell gap d. The fast response time in ECB cell among the three kinds of LCD operating modes was achieved. Also, thermal ability of fast 90 $^{circ} TN-LCD was investigated. The threshold voltage and the response time of thermal stressed TN-LCOs showed the same performances on no thermal stressed TN-LCOs. There was little change of value in these TN cells. However, the transmittances of TN-LCOs on the rubbed PI surface decreased while increasing thermal stress time. Therefore, the thermal stability of TN-LCD was decreased by the high thermal stress for the long duration.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.387-392
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• 2011

The value of Photovoltaic as an independent power supply is small, but the city's carbon emissions reduction and for the reduction of fossil fuel use distributed power is the power source to a very high value. However, according to the weather conditions for solar power generation by power fluctuations because of the size distribution to be effective, the big swing for effectively controlling real-time monitoring should be made. But that depends on solar power generation solar radiation forecasts from the National Weather Service does not need to predict it, and this study, the diffuse sky radiation in the history of the solar radiation in the darkness of the clouds, thick and weather forecasts can be inferred from the atmospheric transmittance to announce this value is calculated to represent each weather forecast solar radiation and solar radiation predicted by substituting the expression And the measured solar radiation and CRM (Cloud Cover Radiation Model) technique with an expression of Kasten and Czeplak irradiation when compared to the calculated predictions were verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1873-1878
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• 2013

ITZO ($In_2O_3$ : $SnO_2$ : ZnO = 90wt.% : 5wt.% : 5wt.%) thin films were fabricated on glass substrates (Eagle 2000) at room temperature with various working pressures (1~7 mTorr) by RF magnetron sputtering. The influence of the working pressure on the structural, electrical, and optical properties of the ITZO thin films were investigated. The XRD and FESEM results showed that all ITZO thin films are amorphous structures with very smooth surfaces regardless of the working pressure. Amorphous ITZO thin films deposited at 3 mTorr showed the best properties, such as a low resistivity, high transmittance, and figure of merit of $3.08{\times}10^{-4}{\Omega}{\cdot}cm$, 81 %, and $10.52{\times}10^{-3}{\Omega}^{-1}$, respectively.

• Journal of Sensor Science and Technology
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• v.6 no.5
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• pp.414-422
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• 1997

CdS thin films with low resistivity and adequate transmittance in the visible region for the window of CdS/CdTe hetero junction solar cel1 were prepared by close spaced vapor transport(CSVT) method. The electrical and optical properties of the CdS thin films were investigated in terms of the deposition conditions, such as the substrate temperature, the working pressure, and the source temperature. The substrate temperature, the working pressure, and the source temperature for the optimum deposition of the CdS thin films were $300^{\circ}C$, 100mTorr, and $730^{\circ}C$, respectively. The resistivity and the transmittance of the CdS thin films deposited under this condition were about $7.21{\times}10^{3}{\Omega}cm$ and over 65%, respectively. The crystallinity, the resistivity, and optical band gap were improved greatly compared to the CdS thin films deposited by general high vacuum evaporation.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.116-124
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• 2007

An optical method to measure the size and number density of soot aggregates in diesel exhaust has been proposed in this study. Two laser beams in co-axial alignment transmit a soot loaded exhaust gas flow, and the transmittance at each wavelength is detected by a photo diode simultaneously. The volume equivalent diameter and number density of soot aggregates in the optical path can be theoretically given by the transmittance values measured at two wavelengths. A test conducted by a single cylinder, 4 cycle, small and DI diesel engine shows that the temporal variations of the size and number density of soot aggregates in the diesel exhaust can be measured by the proposed method at a transient mode operation. It is found that the volume equivalent diameter varied temporally from 70 to 110 nm during the period that high soot concentration is observed. One can also conclude that the optical length longer than 1 m in the dynamic range regarding this method is preferable for measuring soot concentration at the level of $1\;mg/m^3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.379-380
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• 2007

The characteristics of a co-sputtered indium zinc tin oxide (IZTO) films prepared by dual target dc magnetron sputtering from IZO and ITO targets at a room temperature are investigated. Film properties, such as sheet resistance, optical transmittance, surface work function and surface roughness were examined as a function of ITO dc power at constant IZO dc power of 100 W. It was shown that the increase of the ITO dc power during co-sputtering of ITO and IZO target resulted in an increase of sheet resistance of the IZTO films. This can be attributed to high resistivity of ITO film prepared at room temperature. Surface smoothness and roughness were investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The synchrotron x-ray scattering results obtained from IZTO film with different ITO contents showed that introduction of ITO atoms into amorphous IZO film resulted in a crystallization of IZTO film with (222) preferred orientation due to low alc transition temperature of ITO film. However, the transmittance of the IZTO films with thickness of 150 nm is between 80 and 85 % at wavelength of 550 nm regardless of ITO content. Possible mechanism to explain the ITO and IZO co-sputtering effect on properties of IZTO is suggested.

• Land and Housing Review
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• v.11 no.1
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• pp.87-94
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• 2020

To implement the planning of zero-energy buildings, their energy performance must be improved, and renewable energy applications must also be included. To accelerate the use of renewable energies in such buildings, BIPVs should be actively used in windows and on roofs. Window-type BIPVs are being developed in various forms depending on the size, composition, area ratio of the window, specification of glass, and so on. To analyze the applicability of various solar cells as window-type BIPVs, in this study, we evaluated their applicability, at the current development level, by analyzing the indoor illuminance, heat gain and heat loss; the cooling, heating, and lighting energy levels; and the generation performance of the various solar cells. To enhance the future applicability of window type BIPV, we analyze the overall energy performance of the building, according to changes in visible light transmittance and generation efficiency. The main research results are as follows. The area ratios above the standard illuminance, based on the window type and according to the VLT, were in order of low-e glazing, a-Si window, DSSC window, and c-Si window. The heat gain of the semi-transparent solar cell winodw was remarkably low. The energy consumption of buildings was highest in the order of c-Si window, DSSC window, a-Si window, and clear low-e window. However, in the case of including the power generation performance of the solar cell, the energy consumption was found to be high in order of DSSC window, c-Si window, a-Si window, and clear low-e window. In the future, if a window-type BIPV is developed, we believe that improvement in power generation performance and improvement in visible light transmittance will be needed.