• The Journal of Korean Academy of Prosthodontics
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• v.38 no.2
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• pp.147-159
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• 2000

The purpose of this study was the evaluation of spectral transmission of the commercial three shade guides and the relationship of hue, value, and chroma according to the transmission rate. The spectral transmittance of three shade guides - Vita Lumin Shade Guide, Vintage and Unibond Shade Guide, and Vitapan 3D-Master Shade Guide - were measured. For direct transmission measurements, each shade tabs were placed at the entrance port of the 1mm diameter intergrating sphere. The intensity of the light source passing through the shade tabs to the right angle was continuously recorded for wavelength from 400 to 700 nm. A transmission spectrum and digital data were obtained for each measurement and they were evaluated using Microcal Origin program. The obtained results of this study were as follows : 1. In Vita Lumin Shade Guide, sum of the transmission rate of the shade tabs at the wavelength 400-700nm was decreased in agreement with the arrangement order at each A, B, C, D group, except D4 shade tab. However, there were no relationships between the transmission rate of the shade tabs and the value-oriented. 2. In Vintage and Unibond Shade Guide, sum of the total transmission rate of the shade tabs was decreased in agreement with the arrangement order at each A, B, C, B group. When all shade tabs arranged in value-oriented, transmission rate was accord with the order, except D4 shade tab. 3. When shade tabs of the Vitapan 3D-Master Shade Guide have the same value and hue, sum of their total transmission rate decreased in accordance with the chroma-oriented. When the shade tabs have the same value and chroma, there were no differences from the order of the transmission rate to the various hue type. However, in the 'R' tabs of reddish hue type, the transmission rate increased at the long wavelength range area. In conclusion, we need the quantitative analyzing instruments in transmission determination. Vitapan 3D-Master Shade Guide covers the tooth color space taking into account the parameters of the systematic value, chroma, hue oriented, and the transmission rate relatively accorded with that sequence.

• Journal of the Korean Ceramic Society
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• v.41 no.2
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• pp.136-142
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• 2004

A homogeneous and stable ZnO sol was prepared by dissolving the zinc acetate dihydrate(Zn(CH$_3$COO)$_2$$.$2H$_2$O) in solution of isopropanol((CH$_3$)$_2$$.$CHOH) and monoethanolamine(MEA:H$_2$NCH$_2$CH$_2$OH). ZnO thin films were prepared by sol-gel spin-coating method and investigated for c-axis preferred orientation and physical properties with preheating temperature. The c-axis growth had a difference as increaing preheating temperature. ZnO thin film preheated at 275$^{\circ}C$ and post-heated at 650$^{\circ}C$ was highly oriented along the (002) plane. After preheating at 200∼300$^{\circ}C$ and post-heating at 650$^{\circ}C$, the transmittance of ZnO thin films by UV-vis. measurement was over 85% in visible range and exhibited absorption edges at about 370 nm. The optical band gap energy was obtained about 3.22 eV, The photoluminescence emission characteristics of ZnO thin film preheated at 275$^{\circ}C$ and post-heated at 650$^{\circ}C$ was found to orange emission(620 nm, 2.0 eV) by PL measurement, which revealed the possibility for application of inorganic photoluminescence device.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.34-42
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• 1996

This study was conducted to investigate the physical and optical properties of polypropylene and polyester thermal curtains, in which tensile strength, heat reservance and light transmission of two different materials were measured. The results from this study are as follows. 1. The tensile weight of different materials were ranged from 3.4kg to 13.4kg, according to the thickness of materials, but that no difference in the tensile strength was appeared between the two materials. The Elongation of polypropylene materials and the tensile weight and strength of polyester materials were greater than any other materials. 2. The light transmittances of two materials were ranged from 50.3% to 81.7 %, light transmittances in polypropylene were higher by 20-30%,than those in polyester. 3. The heat reservances of two materials were ranged from 18.2% to 41.2%, in which polypropylene showed better performance than polyester. 4. From the results of the test, the polypropylene thermal material was better in elongation, heat reservances and light transmittances, but polyester thermal material was better in tensile strength and light isolation than the other material.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.5
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• pp.262-267
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• 2009

Superhydrophobic $TiO_2$ thin films were successfully fabricated on a glass substrate by wet process. Layer-by-layer (LBL) deposition and liquid phase deposition (LPD) methods were used to fabricate the thin films of micro-nano complex structure with a high roughness. To fabricate superhydrophobic $TiO_2$ thin films, the (PAH/PAA) thin films were assembled on a glass substrate by LBL method and then $TiO_2$ nanoparticles were deposited on the surface of (PAH/PAA) thin film by LPD method, Subsequently, hydrophobic treatment using fluoroalkyltrimethoxysilane (FAS) was carried out on the surface of prepared $TiO_2$ thin films. The $TiO_2$ thin film fabricated with 45 minutes immersion time on $(PAH/PAA)_{10}$ showed the RMS roughness of 65.6nm, water contact angel of $155^{\circ}$ and high transmittance of above 80% (>650nm in wavelength) after the hydrophobic treatment. The Surface morphologies, optical properties and contact angel of prepared thin films with different experimental conditions were measured by field emission scanning electron microscope (FE-SEM), atomic force microscope (AFM), UV-Vis spectrophotometer and contact angle meter.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.9-15
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• 2008

Various diatomic inorganic films and their composite films are packed as passivation films covering Ca cells on glass substrates by using an electron-beam evaporation technique. When these Ca cells are exposed to an ambient atmosphere, the water vapor penetrating through the passivation layers is absorbed in the Ca cells, resulting in a gradual progress of transparency in the Ca cells, which can be represented by changes of the optical transmittance in the visible range. Compared with the saturation times for the Ca cells to become completely transparent in the atmosphere, the protection effects of water vapor are estimated for various passivation films. The composite films consisting silicon oxide($SiO_2$) and tin oxide($SnO_2$) or zinc oxide(ZnO) are found to show a superior protection effect of water vapor as compared with diatomic inorganic films. Also, the main factors affecting the permeation of water vapor through the oxide films are found to be the polarizability and the packing density.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.73-79
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• 2008

In order to apply for transparent conductive oxide(TCO), we deposited ZnO thin films on the glass at room temperature by RF magnetron sputtering method. Deposition conditions for high transmittance and low resistivity were optimized in our previous studies. Under the deposition condition with the RF power of 200 W, target to substrate distance of 30 mm and working pressure of 5 mTorr, highly conductive($7.4{\times}10^{-3}{\Omega}cm$) and transparent(over 85%) ZnO films were prepared. Highly oriented ZnO film in the [002] direction were obtained with specifically designed ZnO targets. Systematic study on dependence of deposition parameters on electrical and optical properties of the as-grown ZnO films were mainly investigated in this work. And for application tests using these films as transparent conductive oxide anodes, wet chemical etching behaviors of ZnO films were also investigated using various chemicals. Wet-chemical etching behavior of ZnO films were investigated using various acid solutions. The concentrations of these different acid solutions were controlled to study the etching shapes and etching rate. ZnO films were anisotropically etched at various concentrations and wet etching led to crater-like surface structure. Also we firstly found that the etching rate and etching shapes of ZnO films strongly depended on the etchant concentrations (i.e. pH) and the etching rate is exponentially decreased with increasing pH values regardless of the acid etchants.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.5
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• pp.449-460
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• 2014

Since the emergence of domestically produced automobiles in 1964, the number of automobiles in circulation in South Korea has increased constantly. With this rapidly increasing number of automobiles, automobile-induced environmental pollution has become an issue of great concern, especially with regard to air pollution. Of the carbon composites contained in automobile exhaust gas, PAHs are known to be carcinogenic and highly deleterious to humans and thus need to be urgently mitigated. To address this issue of PAHs, this study was conducted to estimate qualitative of particulate PAHs contained in carbon composites in automobile exhaust gas, by capturing all particulate matter discharged from the latter. To allow for differentiated analyses, the automobiles investigated were divided into 4 groups: gasoline vehicle, motocycle, diesel vehicle, and LPG vehicle. Samples were analyzed using two methods. First, in-depth analysis was performed on organic carbon (OC) and elemental carbon (EC) composites with analysis parameters, using the Thermal Optical Transmittance Method (NIOSH 5040). Second, for the examination of particulate PAHs, GC/MSD was used to analyze the 16 PAH species specified by the Environmental Protection Agency (EPA). The analyses yielded the findings that diesel vehicles had the highest mass concentration ($2,007{\mu}g/m^3$), followed by motocycle ($1,066{\mu}g/m^3$), LPG vehicle ($392{\mu}g/m^3$), and gasoline vehicles ($270{\mu}g/m^3$). The highest carbon concentrations in total particulate matter by vehicle weight were produced from LPG vehicle (79.8%), followed by gasoline vehicle (77.4%), motocycle (69.8%), and diesel vehicle (59.1%).

• Korean journal of food and cookery science
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• v.3 no.1
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• pp.47-53
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• 1987

The physicochemical properties of kidney bean crude and refined starch were investigated. The results were as follows : Amylose content of refined starch was 77%. Blue values of crude and refined starch were 0.375 and 0.410, respectively. Ferricyanide numbers of crude and refined starch were 1.00 and 1.94, respectively, and alkalinumbers of crude and refined starch were 8.67 and 6.90, respectively. Amylose had molecular weight of 18067 and degree of polymerization was 112. Amylopectin had degree of branching of 3.7 per 100 glucose units and glucose units of 27 per segment of amylopectin. Water binding capacities of crude and refined starch were 202.1% and 169.4%, respectively. Both swelling powers of crude and refined starch were increased rapidly from $70^{\circ}C$ to $90^{\circ}C$ and their curves showed a single-stage pattern. The optical transmittance of 0.2% crude starch suspension was increased rapidly from $80^{\circ}C$ to $83^{\circ}C$ and that of 0.2% refined starch suspension was increased rapidly from $77^{\circ}C$ to $83^{\circ}C$. Brabender hot-paste viscosities of crude and refined starch at 6% and 8% concentation (solid basis) showed the similar amylogram patterns of c type with no peak vircosity.

• Korean journal of food and cookery science
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• v.3 no.1
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• pp.31-36
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• 1987

The purpose of this study is to investigate the physicochemcal Properties of the cowpea crude and refined starch and to present the basic data for physicochemical factor which gives the properties of Mook to cowpea starch gel. Water binding capacity of crude starch was 235. In and that of refined starch was 186.0%. The pattern of change in swelling power and solubility for increasing temperature started to increase at $60^{\circ}C$ and increased rapidly from $70^{\circ}C$, for both of crude and refined starch. The optical transmittance of 0.2% crude and refined starch suspensions were increased from $65^{\circ}C$ and showed rapid increasement during 68~$80^{\circ}C$, and their curves showed two-stage processes. The gelatinization pattern for 6n crude and refined starch suspensions were investigated by the Brabender amylograph. The corves showed the pasting temperature of $72.0^{\circ}C$ and $72.1^{\circ}C$, peak height of 11303.U. ($88.0^{\circ}C$) and 970 B.U. ($83.5^{\circ}C$) for crude and refined starch, respectively, and both showed high viscosities when cooling. Blue values for crude and refined starch were 0.369 and 0.376 respectively. Alkali number of crude and refined starch were 7.77 and 7.34, and reducing values were 3.60 and 2. 10, respectively. Amylose content of cowpea starch was 33.7%. Periodate oxidation of the starch fractions resulted that amylose had the average molecular weight of 23590, degree of polymerization of 146 and amylopectin had the degree of branching of 3.42, glucose unit per segment of 29.

• Applied Chemistry for Engineering
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• v.23 no.4
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• pp.377-382
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• 2012

CdS thin films have been widely used as a buffer layer of CIGS semiconductor solar cells to reduce the lattice mismatch between transparent electrode and absorber layer. In order to prepare the CdS films with high transparency and low resistivity, they were deposited by varying Cd concentration with the constant S concentration in the solution using chemical bath deposition method. They were analyzed in terms of structural, optical and electrical properties of CdS films according to the $[S^{2-}]/[Cd^{2+}]$ ratio. In the case of Cd concentration higher than S concectration, CdS thin films were formed mainly by cluster- by-cluster formation due to the homogeneous reaction between Cd and S in the solution. Therefore the grain size increased and the transmittance decreased. On the other hand, in the case of Cd concentration lower than S concentration, CdS films were formed by heterogeneous reaction on the substrate rather than in the solution. The CdS films have the grains with the uniform circular shape of a few hundreds ${\AA}$. As the Cd concentration increased in the solution, the $[S^{2-}]/[Cd^{2+}]$ ratio decreased and the resistivity decreased by the increase in the carrier concentration due to the formation S vacancy by the excess Cd.