• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.371-373
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• 2006

Life history of Ivela auripes (Lepidoptera: Lymantriidae), a pest of Cornus controversa, was investigated both in laboratory and field condition. At $24{\pm}1^{\circ}C$, developmental period from larvae to adult and adult life span was $26.3{\pm}0.3$ and $4.4{\pm}0.2$ days, respectively. Developmental period of pupae reared in the laboratory was not significantly different from those collected in the field. Female moths reared in the laboratory laid significantly less eggs than those emerged from the pupae collected in the field. Light trap catches was less effective than direct monitoring in the field. The two monitoring results showed that adult moth emerged from early June to late June, and the time of 50% cumulative emergence was 17 June.

• Restorative Dentistry and Endodontics
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• v.28 no.5
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• pp.402-408
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• 2003

This study was done to present a criterion in selection of the most proper light sources and materials by measuring metamerism index(MI) of the light curing composite resins with spectrocolorimeter. Metamerism is defined when two objects appear to be the same color in one illuminant but different in another. This is due to the fact that they have different spectral curves that fail to match under the second illuminant. In this study, A1 & A3 shade of five light curing composite resins (Esthet-X, Filteck Z250, Filteck A110. Charisma. Vitalescence) were chosen based on Vita shade. Five samples were made for shade of each product with Teflon mold (diameter: 15mm, thickness: 2mm). Metamerism index of each samples on a Barium sulfate plate($L^{*}=96.54,{\;}a^{*}=0.19,{\;}b^{*}=0.01$) prepared for sample fixation were measured with spectrocolorimeter(Miniscan XE plus. Model 4000s. Hunter Lab. USA) by applying standard light source D^{65}, C. Fcw, TL84 and A. Standardization was done with reference standard(X=80.8, Y=85.7, Z=90.8) and light trap. The results were as follows. 1. Different resins with same Vita shade showed recognizable color difference (${\delta}E^{*}>2$). 2. All composites had MI below accepted value 0.5 between standard illuminant(D$_{65}$, C, & A) and below 1.5 under fluorescent condition (Fcw & TL84). 3. MI value between $D^{65}$ and A showed higher value than MI value between other source of light(p<0.01). 4. All resins except Z250 showed MI value that A3 is higher than A1 between $D^{65}$ and A(p<0.05).except Z250 showed MI value that A3 is higher than A1 between $D^{65}$ and A(p<0.05).

• Korean journal of applied entomology
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• v.41 no.4
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• pp.233-238
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• 2002

The seasonal occurrence trends of the brown-winged green bug, Plautia stali, and the brown malmorated stink bug, Halyomorpha halys, were monitored in sweet persimmon orchards in southern region of Korea using light traps (in 2000 and 2001), and aggregation pheromone traps (methyl (E, E, Z)-2 ,4, 6-decatrienoate)) of P. stali (in 2001). Light trap data showed that H. halys started to occur from the end of June, and reached its peak in early or mid August, while P. stali was mostly attracted to the traps from mid July to late August without any distinct attraction peak. Both species did not occur after September in the persimmon orchards studied. The attraction patterns of both species to aggregation pheromone traps were different from those observed in light traps. Both species were attracted to the pheromone traps from mid May to late August. The peak occurrence of H. halys could not be detected due to low catches. However, the period of peak attraction for P. stali was from late June to late August depending on the geographical locations. The aggregation pheromone traps of P. stali attracted more number of P stali than H. hails, but the light traps showed a reverse pattern. In both species, more females were attracted to the aggregation pheromone traps than males. The difference of attraction patterns between 2 types of traps was discussed in relation to content of soluble tannin in persimmon fruits.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.28-28
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• 2009

Fabrications of antireflection structures on solar cell were investigated to trap the light and to improve quantum efficiency. Introductions of patterned substrate or textured layer for Si solar cell were performed to prevent reflectance and to increase the path length of incoming light. However, it is difficult to deposit conformally flat electrode on perpendicular plane. ZnO is II-VI compound semiconductor and well-known wide band-gap material. It has similar electrical and optical properties as ITO, but it is nontoxic and stable. In this study, Al-doped ZnO thin films are deposited as transparent electrode by atomic layer deposition method to coat on Si substrate with micro-scale structures. The deposited AZO layer is flatted on horizontal plane as well as perpendicular one with conformal 200 nm thickness. The carrier concentration, mobility and resistivity of deposited AZO thin film on glass substrate were measured $1.4\times10^{20}cm^{-3}$, $93.3cm^2/Vs$, $4.732\times10^{-4}{\Omega}cm$ with high transmittance over 80%. The AZO films were coated with polyimide and performed selective polyimide stripping on head of column by reactive ion etching to measure resistance along columns surface. Current between the micro-columns flows onto the perpendicular plane of deposited AZO film with low resistance.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.3
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• pp.130-134
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• 2009

A new long persistent phosphors of $CaZrO_3$ was synthesized at high temperature with weak reduction atmosphere by a traditional solid state reaction method. Photoluminescence spectra analysis showed that the $CaZrO_3$ doped with $Tb^{3+}$ emitted green-yellow emission caused by the energy level transition from the $^5D_3$ and $^5D_4$ to $^7F_1{\sim}^7F_6$. The main emission spectra of 542 nm peak by the $^5D_4{\rightarrow}^7F_5$ transition was revealed through synthesizing at high temperature in $N_2$ gas atmosphere. The afterglow emission spectra of $CaZrO_3:Tb^{3+}$ long persistent phosphores arise at 546 nm peak of narrow range. After the 254 nm ultraviolet light excitation source was switched off, the green-yellow long persistent phosphor can be observed which could last for 8 h in the limit of light perception of dark-adapted human eyes ($0.32\;mcd/m^2$).

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.150-155
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• 2012

Lean NOx Trap (LNT) catalysts are capable of reducing exhaust NOx emissions from diesel engines. LNT stores NOx in lean condition and exhausts N2 by reducing NOx in rich condition. NOx reduction characteristic of LNT catalysts using throttle position sensor and fuel injection timing control for light-duty diesel engine was investigated. In contrast to SCR system, LNT catalyst uses diesel fuel in resuctant. Also if the concentration of reductant is exceeded, excessive amount of reductant will slip throughout LNT and cause another emission problem. Thus LNT regeneration with precise engine control established that can make higher NOx conversion efficiency and lower fuel penalty, prevent another emission problem. NOx and reductant concentration were measured by the NOx sensor and Mexa7100D equipped inlet and outlet of catalyst. As a result of engine test, regeneration strategy has reached high of 77.8% NOx conversion efficiency according to engine operation condition. Moreover, we have proved that it is possible to use regeneration strategy of LNT within 5% fuel penalty.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.400-405
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• 2004

Since a large bank-protection works project was undertaken during winter in the middle reaches of the Chikuma, the riverbed structure was drastically altered. In order to assess the short-term impact of bank-protection works on the abundance Pattern of Stenopsyche marmorata (Trichoptera) from spring to early summer, we conducted an investigation on the capture of adults using light traps before and after construction work. The patterns of the daily capture of S. marmorata and the Namely, after construction, the daily catch of adult numbers increased only slightly during the investigation periods. This suggested that the age structure of the S. marmorata larval population had changed in the construction area. Our data suggest that bank-protection projects impact the abundance pattern of adult caddisflies in the river ecosystem.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.162-162
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• 2011

Nanometer-sized noble metals can trap and guide sunlight for enhanced absorption of light based on surface plasmon that is beneficial for generation of hot electron flows. A pulse of high kinetic energy electrons (1-3 eV), or hot electrons, in metals can be generated after surface exposure to external energy, such as in the absorption of light or in exothermic chemical processes. These energetic electrons are not at thermal equilibrium with the metal atoms. It is highly probable that the correlation between hot electron generation and surface plasmon can offer a new guide for energy conversion systems [1-3]. We show that hot electron flow is generated on the modified gold thin film (<10 nm) of metal-semiconductor (TiO2) Schottky diodes by photon absorption, which is amplified by localized surface plasmon resonance. The short-circuit photocurrent obtained with low energy photons (lower than bandgap of TiO2, ~3.1-3.2 eV) is consistent with Fowler's law, confirming the presence of hot electron flows. The morphology of the metal thin film was modified to a connected gold island structure after heating to 120, 160, 200, and 240$^{\circ}C$. These connected island structures exhibit both a significant increase in hot electron flow and a localized surface plasmon with the peak energy at 550-570 nm, which was separately characterized with UV-Vis [4]. The result indicates a strong correlation between the hot electron flow and localized surface plasmon resonance with possible application in hot electron based solar cells and photodetectors.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.292-297
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• 2003

We fabricated a single crystal silicon thin film transistor for active matrix organic light emitting displays(AMOLEDs) using silicon on insulator wafer (SOI wafer). Poly crystal silicon thin film transistor(poly-Si TFT) Is actively researched and developed nowsdays for a pixel switching devices of AMOLEDs. However, poly-Si TFT has some disadvantages such as high off-state leakage currents and low field-effect mobility due to a trap of grain boundary in active channel. While single crystal silicon TFT has many advantages such as high field effect mobility, low off-state leakage currents, low power consumption because of the low threshold voltage and simultaneous integration of driving ICs on a substrate. In our experiment, we compared the property of poly-Si TFT with that of SOI TFT. Poly-Si TFT exhibited a field effect mobility of 34 $\textrm{cm}^2$/Vs, an off-state leakage current of about l${\times}$10$\^$-9/ A at the gate voltage of 10 V, a subthreshold slope of 0.5 V/dec and on/off ratio of 10$\^$-4/, a threshold voltage of 7.8 V. Otherwise, single crystal silicon TFT on SOI wafer exhibited a field effect mobility of 750 $\textrm{cm}^2$/Vs, an off-state leakage current of about 1${\times}$10$\^$-10/ A at the gate voltage of 10 V, a subthreshold slope of 0.59 V/dec and on/off ratio of 10$\^$7/, a threshold voltage of 6.75 V. So, we observed that the properties of single crystal silicon TFT using SOI wafer are better than those of Poly Si TFT. For the pixel driver in AMOLEDs, the best suitable pixel driver is single crystal silicon TFT using SOI wafer.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.129-135
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• 2009

We investigated the moth diversity on an island of southern sea of Korea. We collected moths at three sites on the island of Bogildo, Wando-gun, Jeonnam using a 22-watt ultraviolet light trap from May to October, 2008, and identified a total of 272 species and 948 individuals in 13 families. Species of Noctuidae was the most abundant, with 107 species and 318 individuals, followed by Geometridae (62 species and 147 individuals) and Pyralidae (53 species and 269 individuals). The graph of the estimated species richness in Chao 1 (432.25$\pm$37.39) did not reach an asymptote, which suggests that more moth species could be identified on the island through further sampling. An arctiid moth, Miltochrista striata, was the most abundant species captured in this study. Monthly changes in moth species richness and abundance formed M-shaped curves, with peaks in early summer (June) and late summer (August). Cluster analysis of seven sites on three islands (Aphaedo Island, Sinan-gun, Oenarodo Island, Goheung-gun and Bogildo Island) divided the sites into two groups. Distances among sites and habitat types may play an important role in determining the similarities of moth faunas among sites.