• The Journal of Korean Academy of Prosthodontics
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• v.45 no.1
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• pp.21-33
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• 2007

Statement of problem: The esthetic component of dental care has become increasingly more important, while new tooth-colored materials are continually marketed. Various new indirect composite materials have been developed with required advantages. The most recent development in the indirect composites has been the introduction of the second-generation laboratory composite or poly-glass materials. They are processed by different laboratory techniques based on combinations of heat, pressure, vacuum and light polymerization. Although, second generation products became available in 1995, their characteristics and clinical performance have not been adequately investigated. Purpose: The aim of this study was to measure the mechanical properties of the second generation indirect resin system and compare these with an existing universal direct composite resin. Material and method: In this study four indirect composite material (Adoro LC, BelleGlass HP, Tescera, Synfony) were tested for flexural strength, wear resistance, hardness and their degree of conversion against Z250, a light cure direct composite. Results: Within the limitations of this study, the following conclusions were drawn: 1. From the abrasion wear result, Adoro showed the least volume loss while Synfony showed the greatest volume loss. Z250 and BelleGlass HP didn't show significant difference (p>0.05), but they showed significant difference with other groups (p<0.05). From the attrition wear, BelleGlass HP showed the least volume loss and it didn’t show significant difference with Tescera (p>0.05). While Synfony showed the greatest volume loss that it showed significant difference with other groups (p>0.05). 2. Mean values of flexural strength by means of three point bending test was in the order of Z250, Adoro, Belleglass HP, Tescera and Synfony. Mean elastic modulus was in the order of Z250, BelleGlass HP, Tescera, Adoro and Synfony. 3. The result of Vicker‘s microhardness value showed that significantly higher value in Z250 (p<0.05), and is in the order of BelleGlass HP, Tescera, Adoro and Synfony. 4. The degree of conversion measured by FT-IR showed significantly higher value in BelleGlass HP (p<0.05), and is in the order of Adoro, Synfony, Tescera and Z250. Conclusion: Significant differences were found in the flexural strength, wear resistance, hardness and their degree of conversion.

• Journal of Advanced Navigation Technology
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• v.18 no.1
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• pp.35-43
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• 2014

In this paper, it is about to non-contact wireless power transmission according to various conditions of self induction principle between the two planar coils at a transmission unit and a receiving unit based on the theory of wireless power transmission. The experiments are occurred in order to power transfer of noncontact method from designed wireless circuits in the primely coil and secondary coil, and the applying to Half Bridge Resonant converter transmission unit and receiving unit. and that were able to prepared circumstance to calculate of the output voltage and power source. The main power of the inductive coupling the resonant converter at the transmission unit is converted electrical energy using the solar cell module and artificial light source (halogen lamp) as a replace light and received 24 V power supply from solar power was used a input power source for the wireless power transmission device. Experimental results, to received of power is used to illuminate the lighting and to charge the battery in receiving circuit.And the wireless power transmission efficiency measured at the output side of the transmission unit is obtained about 70% to 89% compared to input power of receiving unit.In addition, efficiency were tested through ID verification method and comparing the phase difference between the voltage when foreign substances interfere with wireless power transmission.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.296-296
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• 2014

We investigate experimentally and theoretically the splitting of surface plasmon (SP) resonance peaks under TE- and TM-polarized illumination. The SP structure at infrared wavelength is fabricated with a 2-dimensional square periodic array of circular holes penetrating through Au (gold) film. In brief, the processing steps to fabricate the SP structure are as follows. (i) A standard optical lithography was performed to produce to a periodic array of photoresist (PR) circular cylinders. (ii) After the PR pattern, e-beam evaporation was used to deposit a 50-nm thick layer of Au. (iii) A lift-off processing with acetone to remove the PR layer, leading to final structure (pitch, $p=2.2{\mu}m$; aperture size, $d=1.1{\mu}m$) as shown in Fig. 1(a). The transmission is measured using a Nicolet Fourier-transform infrared spectroscopy (FTIR) at the incident angle from $0^{\circ}$ to $36^{\circ}$ with a step of $4^{\circ}$ both in TE and TM polarization. Measured first and second order SP resonances at interface between Au and GaAs exhibit the splitting into two branches under TM-polarized light as shown in Fig. 1(b). However, as the incidence angle under TE polarization is increased, the $1^{st}$ order SP resonance peak blue-shifts slightly while the splitting of $2^{nd}$ order SP resonance peak tends to be larger (not shown here). For the purpose of understanding our experimental results qualitatively, SP resonance peak wavelengths can be calculated from momentum matching condition (black circle depicted in Fig. 2(b)), $k_{sp}=k_{\parallel}{\pm}iG_x{\pm}jG_y$, where $k_{sp}$ is the SP wavevector, $k_{\parallel}$ is the in-plane component of incident light wavevector, i and j are SP coupling order, and G is the grating momentum wavevector. Moreover, for better understanding we performed 3D full field electromagnetic simulations of SP structure using a finite integration technique (CST Microwave Studio). Fig. 1(b) shows an excellent agreement between the experimental, calculated and CST-simulated splitting of SP resonance peaks with various incidence angles under TM-polarized illumination (TE results are not shown here). The simulated z-component electric field (Ez) distribution at incident angle, $4^{\circ}$ and $16^{\circ}$ under TM polarization and at the corresponding SP resonance wavelength is shown in Fig. 1(c). The analysis and comparison of theoretical results with experiment indicates a good agreement of the splitting behavior of the surface plasmon resonance modes at oblique incidence both in TE and TM polarization.

• Journal of Conservation Science
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• v.32 no.4
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• pp.501-510
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• 2016

In this study, we investigated the degradation of adhesives when exposed to ultraviolet light irradiation using samples of lacquer (L), treated lacquer (TL), lacquer mixed with glue (LG), and urushiol mixed with glue (UG). Four types of film specimens were collected under the ultraviolet exposure time, and gloss test, tensile shear strength test, scanning electron microscope analysis, and infrared spectroscopic analysis were conducted for the specimens. LG and UG showed lowering rate of gloss is somewhat later than L. Also, it was observed that with increasing exposure time to ultraviolet irradiation, the surface of L began to show spherical pits and cracks when the polysaccharide layers started to be exposed, whereas the surfaces of LG and UG remained smooth. The Infrared spectra of L and TL showed that the intensity of the overall peak decreased with increasing ultraviolet irradiation time. There was no change in the peak intensity of LG, but for UG, the peaks at $3013cm^{-1}$, $1593cm^{-1}$ and so on disappeared and the overall intensity declined. The tensile shear strength of LG and UG was maintained or increased as compared to the initial test, whereas the tensile shear strength of L decreased sharply after 600 h. LG and UG exhibited fewer changes as a result of high temperature and humidity conditions, and they retained their strength under UV exposure. These results indicate that LG and UG are more durable than L when subjected to environmental change.

• Preventive Nutrition and Food Science
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• v.8 no.2
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• pp.166-172
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• 2003

Calcium lactate (CL) prepared from powdered black snail (PBS) or its ashed powder (ABS), was investigated for ideal manufacturing conditions to optimize color, solubility and sensory quality. Based on the amount of PBS and 100 mL lactic acid (LA), the yields of PBS-CL were 300% and 15 g in 10% LA and 260% and 20 g in 20% LA. Yields of ABS-CL based on the amount ABS and 100 mL LA were 400% and 60 g in 10% LA and 329% and 66 g in 20% LA. Both of the yields were decreased with an increase of the LA concentration on the basis of PBS and ABS amounts, but proportionally increased with the increment in the LA concentration on the basis of LA volume. Optimal preparation times of the dehydrated PBS-CL and ABS-CL were, respectively, 4 hr and 5 hr at 10$0^{\circ}C$, 3 hr and 4 hr at 12$0^{\circ}C$, and 1 hr and 2 hr at 15$0^{\circ}C$, which showed shorter time in preparing the dehydrated ABS-CL. PBS-CL and ABS-CL were confirmed to be Ca($CH_3$CHOH$CO_2$)$_2$ by the analysis results of IR and $^1$H-NMR. Calcium contents of the anhydrous PBS-CL and ABS-CL were individually 15.4% (w/w) and 17.3% (w/w) representing 84.2% and 94.5% or each theoretical value. Colors or PBS-CL and ABS-CL were light yellow and light-greenish white each. Solubilities of PBS- CL and ABS-CL in distilled water at pH 3~8 were 5.43 and 6.11 g/100 mL, respectively, which demonstrated higher mean solubilities rather than the 4.74 g/100 mL of standard CL. Solubilities of PBS-CL (3.14~5.03 g/100 mL) and ABS-CL (4.69~6.05 g/100 mL) against soup soy sauce, 3% brine, Soju (Korean distilled liquor), thick soy sauce, grape juice and orange juice were higher than those of standard CL (2.94~5.84 g/100 mL). ABS-CL was believed to have a wide use range due to its low sourness while different applications of PBS-CL in food are expected due to its mild astringent taste and strong savory taste despite its strong bitter taste as estimated by sensory evaluation.

• Journal of Sensor Science and Technology
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• v.8 no.3
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• pp.239-246
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• 1999

A highly sensitive photovoltaic infrared photodiode was fabricated for detecting infrared light in $3{\sim}5\;{\mu}m$ wavelength range on InSb wafer with p-i-n structure grown by MOCVD. Silicon dioxide($SiO_2$) insulating films for the junction interface and surface of photodiode were prepared using RPCVD because InSb has low melting point and evaporation temperature. After formation of In ohmic contacts by thermal evaporation, the electrical properties of the photodiode were characterized in dark state at 77K. A product of zero-bias resistance and area($R_0A$) showed $1.56{\times}10^6\;{\Omega}{\cdot}cm^2$ that satisfied BLIP(background limited infrared photodetector) condition. When the photodiode was tested under infrared light, the normalized detectivity of about $10^{11}\;cm{\cdot}Hz^{1/2}{\cdot}W^{-1}$ was obtained. we successfully fabricated a unit cell with InSb IR array with good quantum efficiency and high detectivity.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.1
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• pp.27-34
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• 2015

Many applications of nanoparticles have been developed since 1970s. Surface plasmon resonance (SPR) effect can be generated at the surface of nanoparticles by illumination. SPR is the resonant oscillation of conduction electrons at the surface material stimulated by incident light. The collisions between excited electrons and metal atoms can cause the production of thermal energy (photothermal effect). Here, we presented the development of thermo-cosmetics using photothermal effect of gold nanoparticles. Gold nanoparticles (GNPs) were chosen for it's low toxicity. We also and investigated the cell biocompatibility and heating effectiveness for photothermal effect of GNPs. Synthesized GNPs were verified by UV-vis spectrophotometer, where GNP has a characteristic absorbance spectrum. Concentration of GNP was measured by atomic absorption analyzer. The cytotoxicity was confirmed by MTT assay and double staining assay. Photothermal effect of GNP was demonstrated by the thermal increasing properties depending on GNP concentration, which was taken by an IR-thermal camera with a xenon lamp as the light source. If the thermal effect of GNP is applied for thermo-cosmetics, it can supply heat to skin by converting solar energy into thermal energy. Thus, cosmetics containing GNPs can provide benefits to people in the cold region or winter season for maintaining skin temperature, which lead to a positive effect on skin health.

• Journal of IKEEE
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• v.13 no.1
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• pp.57-64
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• 2009

The optoelectrical characteristics of the ZnO nanoparticles (NPs) annealed in vacuum or oxygen condition from $200^{\circ}C$ to $600^{\circ}C$ were examined. Increased on-off ratio (or, the ratio of photocurrent to dark current) was observed when they were annealed at $300^{\circ}C$, $400^{\circ}C$ and $500^{\circ}C$ with the values enhanced about 4 orders compared to the as-prepared ZnO NPs in both annealing conditions, while the maximum efficiency was shown at the annealing temperature of $600^{\circ}C$ for the ZnO NPs annealed in vacuum with the value of 29.8 mA/W and at the temperature of $500^{\circ}C$ for those annealed in oxygen condition with the value of 40.3 mA/W. Photoresponse behavior of the ZnO NPs annealed in oxygen showed the sharp increase right after the ir exposure to the light followed by the slow decay and saturation during steady illumination, differing from the ZnO NPs annealed in vacuum which only exhibited the gradual increase. This difference occurred due to the curing effect of the oxygen vacancies. SEM images indicated no change in their morphologies with annealing, indicating the change in their internal structures by annealing, and most remarkably at $600^{\circ}C$. As for their photoluminescence(PL) spectra, the decrease of the deep-level(DL) emission was observed when they were annealed in oxygen at $400^{\circ}C$, and not at $200^{\circ}C$ and $600^{\circ}C$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.710-715
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• 1999

The purpose of this work is to develop a high-efficiency air cleaning system for air pollutants such as particulate and gaseous state in indoor environments. In order to enhance a removal efficiency of gaseous state pollutants, we suggested that pulsed discharge plasma be combined with $TiO_2$ photocatalyst (photocatalytic plasma air cleaning unit). We investigated experimentally the basic characteristics of photocatalytic plasma air cleaning unit and measured air pollutants removal efficiency. The wavelength of light radiated from pulsed discharge plasma under the atmospheric condition was 310~380nm. Its energy is enough to excite the $TiO_2$ photocatalyst and it makes a photochemical reaction in the surface of $TiO_2$ photocatalyst. The removal quantity of trimethylamine$((CH_3)_3N)\; was\; 130mg/m^34 which is twice quantity of pulsed discharge plasma without $TiO_2$ phtocatalyst unit. From the result of gas analysis using FT-IR, nitric oxide was not detected and trimethylamine was decomposed to $H_2O\; and \;CO_2$. And trimethylamine removal efficiency was 95%. These experimental results indicate that photocatalytic plasma air cleaning unit is a potential method in removing the pollutants.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1800-1808
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• 2013

Dual-responsive amphiphilic block copolymers were synthesized by combining enzymatic ring-opening polymerization (eROP) of ${\varepsilon}$-caprolactone (CL) and ATRP of N,N-dimethylamino-2-ethyl methacrylate (DMAEMA). The obtained block copolymers were characterized by gel permeation chromatography (GPC), $^1H$ NMR and FTIR-IR. The critical micelle concentration (CMC) of copolymer was determined by fluorescence spectra, it can be found that with hydrophilic block (PDMAEMA) increasing, CMC value of the polymer sample increased accordingly, and the CMC value was 0.012 mg/mL, 0.025 mg/mL and 0.037 mg/mL for $PCL_{50}$-b-$PDMAEMA_{68}$, $PCL_{50}$-b-$PDMAEMA_{89}$, $PCL_{50}$-b-$PDMAEMA_{112}$, $PCL_{50}$-b-$PDMAEMA_{89}$ was chosen as drug carrier to study in vitro release profile of anti-cancer drug (taxol). The temperature and pH dependence of the values of hydrodynamic diameter (Dh) of micelles, and self-assembly of the resulting block copolymers in water were evaluated by dynamic light scattering (DLS). The result showed that with the temperature increasing and pH decreasing, the Dh decreased. Drug-loaded nanoparticles were fabricated using paclitaxel as model. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) had been explored to study the morphology of the hollow micelles and the nanoparticles, revealing well-dispersed spheres with the average diameters both around 80 nm. In vitro release kinetics of paclitaxel from the nanoparticles was also investigated in different conditions (pH and temperature, etc.), revealing that the drug release was triggered by temperature changes upon the lower critical solution temperature (LCST) at pH 7.4, and at $37^{\circ}C$ by an increase of pH.