• Electrical & Electronic Materials
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• v.12 no.7
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• pp.7-11
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• 1999

Fully sealed field emission display in size of 4.5 inch has been fabricated using single-wall carbon nanotubes-organic vehicle com-posite. The fabricated display were fully scalable at low temperature below 415$^{\circ}C$ and CNTs were vertically aligned using paste squeeze and surface rubbing techniques. The turn-on fields of 1V/${\mu}{\textrm}{m}$ and field emis-sion current of 1.5mA at 3V/${\mu}{\textrm}{m}$ (J=90${\mu}{\textrm}{m}$/$\textrm{cm}^2$)were observed. Brightness of 1800cd/$m^2$ at 3.7V/${\mu}{\textrm}{m}$ was observed on the entire area of 4.5-inch panel from the green phosphor-ITO glass. The fluctuation of the current was found to be about 7% over a 4.5-inch cath-ode area. This reliable result enables us to produce large area full-color flat panel dis-play in the near future. Carbon nanotubes (CNTs) have attracted much attention because of their unique elec-trical properties and their potential applica-tions [1, 2]. Large aspect ratio of CNTs together with high chemical stability. ther-mal conductivity, and high mechanical strength are advantageous for applications to the field emitter [3]. Several results have been reported on the field emissions from multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) grown from arc discharge [4, 5]. De Heer et al. have reported the field emission from nan-otubes aligned by the suspension-filtering method. This approach is too difficult to be fully adopted in integration process. Recently, there have been efforts to make applications to field emission devices using nanotubes. Saito et al. demonstrated a car-bon nanotube-based lamp, which was oper-ated at high voltage (10KV) [8]. Aproto-type diode structure was tested by the size of 100mm $\times$ 10mm in vacuum chamber [9]. the difficulties arise from the arrangement of vertically aligned nanotubes after the growth. Recently vertically aligned carbon nanotubes have been synthesized using plasma-enhanced chemical vapor deposition(CVD) [6, 7]. Yet, control of a large area synthesis is still not easily accessible with such approaches. Here we report integra-tion processes of fully sealed 4.5-inch CNT-field emission displays (FEDs). Low turn-on voltage with high brightness, and stabili-ty clearly demonstrate the potential applica-bility of carbon nanotubes to full color dis-plays in near future. For flat panel display in a large area, car-bon nanotubes-based field emitters were fabricated by using nanotubes-organic vehi-cles. The purified SWNTs, which were syn-thesized by dc arc discharge, were dispersed in iso propyl alcohol, and then mixed with on organic binder. The paste of well-dis-persed carbon nanotubes was squeezed onto the metal-patterned sodalime glass throuhg the metal mesh of 20${\mu}{\textrm}{m}$ in size and subse-quently heat-treated in order to remove the organic binder. The insulating spacers in thickness of 200${\mu}{\textrm}{m}$ are inserted between the lower and upper glasses. The Y\ulcornerO\ulcornerS:Eu, ZnS:Cu, Al, and ZnS:Ag, Cl, phosphors are electrically deposited on the upper glass for red, green, and blue colors, respectively. The typical sizes of each phosphor are 2~3 micron. The assembled structure was sealed in an atmosphere of highly purified Ar gas by means of a glass frit. The display plate was evacuated down to the pressure level of 1$\times$10\ulcorner Torr. Three non-evaporable getters of Ti-Zr-V-Fe were activated during the final heat-exhausting procedure. Finally, the active area of 4.5-inch panel with fully sealed carbon nanotubes was pro-duced. Emission currents were character-ized by the DC-mode and pulse-modulating mode at the voltage up to 800 volts. The brightness of field emission was measured by the Luminance calorimeter (BM-7, Topcon).

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.3
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• pp.271-277
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• 2006

A mechanically pressed juice of Bokbunja (Rubus coreanus Miq.) extract was prepared using 70% ethanol solution. The extract was subjected to gamma-irradiation treatment (20 kGy) and investigated for its change of color and biological activities. Hunter $L^*$ values of the irradiated Bokbunja extract were increased in comparison with the non-irradiated extracts, and the $a^*\;and\;b^*$values decreased by the irradiation treatment. The content of the total phenolic compounds in the non-irradiated and irradiated extracts were 58.4 and 56.5 mg/g, respectively. The 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activities of non-irradiated and irradiated extracts at a 250 ppm level were 80% and 79%, respectively. Lipid oxidation was retarded by addition of Bokbunja powder. Nitrite scavenging activity was the highest in the Bokbunja powder at pH 1.2 and the effect was not changed by irradiation. The Bokbunja powder showed antimicrobial activity against Salmonella Typhimurium and Bacillus cereus. However, irradiation of Bokbunja did not affect any physiological functions (p>0.05). A Salmonella mutagenicity assay indicated that the irradiated Bokbunja extract did not show any mutagenicity. Therefore, Bokbunja extract could be used in various applications as a functional material, such as ingredients of food and cosmetic, compositions with functions.

• Journal of Food Hygiene and Safety
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• v.25 no.4
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• pp.354-359
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• 2010

In the present study, we investigated the chemical composition, antioxidant activities and nitrite scavenging ability in leaf and root of Youngia sonchifolia Max. The leaf powder contained 4.3% of water, 53.9% of crude carbohydrate, 21.6% of crude protein, 3.5% of crude fat and 16.7% of crude ash. The root powder contained 4.8% of water, 65.9% of crude carbohydrate, 17.4% of crude protein, 3.2% of crude fat and 8.7% of crude ash. The major mineral elements both in leaf and root powder were potassium, calcium, and magnesium. Contents of unsaturated fatty acids were higher than those of saturated fatty acids both in leaf and root powder. Total polyphenol and flavonoid contents of methanol extract in leaf were 3,922.4 mg/100 g and 1,903.2 mg/100 g respectively. In comparison, total polyphenol and flavonoid contents of methanol extract in root powder were 1,898.4 mg/100 g and 359.8 mg/100 g. The antioxidative activities of several solvents extract of leaf and root powder were investigated by measuring electron-donating ability using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Of the each extracts, ethyl acetate extract of leaf and root powder showed relatively higher antioxidant activity; 94.3% in the leaf powder and 92.9% in the root powder. Nitrite scavenging ability was also highest in the ethyl acetate extract of leaf (45.4%) and root powder (28.8%). These results suggest that ethyl acetate extract of Youngia sonchifolia Max. can be used as a functional materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.572-580
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• 2017

The contents of phenolic compounds in water and 40% ethanol extracts from Okkwang (Castanea crenata) chestnut bur solid (OCS) were $11.24{\mu}g/50{\mu}g$ solid and $10.28{\mu}g/50{\mu}g$ solid, respectively. The 1,1-diphenyl-2-picrylhydrazyl free radical scavenging and 2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid) radical decolorization activities of water and ethanol extracts were 85% and 100% as well as 87% and 86% at a solid content of $50{\mu}g/mL$, respectively. The anti-oxidant protection factors (PFs) of water and ethanol extracts at a solid content of $200{\mu}g/mL$ were 1.22 PF and 1.45 PF, respectively. Thiobarbituric acid reactive substance were 83% in water extract and 73% in ethanol extract at a solid content of $200{\mu}g/mL$. The inhibitory activities against xanthine oxidase in water and ethanol extracts were 54% and 43% at a solid content of $200{\mu}g/mL$, respectively. The inhibitory activities against ${\alpha}$-glucosidase were 95% in water extract and 96% in ethanol extract at a solid content of $50{\mu}g/mL$. Tyrosinase inhibitory activity was 27% in ethanol extract at a solid content of $200{\mu}g/mL$. The collagenase and elastase inhibitory activities as anti-wrinkle effect were 93% and 11% in water extract as well as 94% and 56% in ethanol extract at a solid content of $200{\mu}g/mL$. Hyaluronidase inhibitory activity as anti-inflammatory effect of water and ethanol extracts were 96% and 52% at a solid content of $200{\mu}g/mL$, respectively. The results show that extracts from OCS can be used as a functional resource with antioxidant, anti-gout, carbohydrate degradation inhibitory, whitening, anti-wrinkle, and anti-inflammatory activities.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.44 no.2 s.314
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• pp.37-46
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• 2007

In this paper, we propose technologies for enhancing the immersive realization of virtual objects in AR-based product design. Generally, multimodal senses such as visual/auditory/tactile feedback are well known as a method for enhancing the immersion in case of interaction with virtual objects. By adapting tangible objects we can provide touch sensation to users. A 3D model of the same scale overlays the whole area of the tangible object so the marker area is invisible. This contributes to enhancing immersion. Also, the hand occlusion problem when the virtual objects overlay the user's hands is partially solved, providing more immersive and natural images to users. Finally, multimodal feedback also creates better immersion. In our work, both vibrotactile feedback through page motors, pneumatic tactile feedback, and sound feedback are considered. In our scenario, a game-phone model is selected, by way of proposed augmented vibrotactile feedback, hands occlusion-reduced visual effects and sound feedback are provided to users. These proposed methodologies will contribute to a better immersive realization of the conventional AR system.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.75-82
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• 2019

Flexible solar cells have attracted enormous attention in recent years due to their wide applications such as portable batteries, wearable devices, robotics, drones, and airplanes. In particular, the demands of the flexible silicon and compound semiconductor solar cells with high efficiency and high reliability keep increasing. In this study, we fabricated a flexible InGaP/GaAs double-junction solar module. Then, the effects of the wind speed and ambient temperature on the operating temperature of the solar cell were analyzed with the numerical simulation. The temperature distributions of the solar modules were analyzed for three different wind speeds of 0 m/s, 2.5 m/s, and 5 m/s, and two different ambient temperature conditions of 25℃ and 33℃. The flexibility of the flexible solar module was also evaluated with the bending tests and numerical bending simulation. When the wind speed was 0 m/s at 25 ℃, the maximum temperature of the solar cell was reached to be 149.7℃. When the wind speed was increased to 2.5 m/s, the temperature of the solar cell was reduced to 66.2℃. In case of the wind speed of 5 m/s, the temperature of the solar cell dropped sharply to 48.3℃. Ambient temperature also influenced the operating temperature of the solar cell. When the ambient temperature increased to 33℃ at 2.5 m/s, the temperature of the solar cell slightly increased to 74.2℃ indicating that the most important parameter affecting the temperature of the solar cell was heat dissipation due to wind speed. Since the maximum temperatures of the solar cell are lower than the glass transition temperatures of the materials used, the chances of thermal deformation and degradation of the module will be very low. The flexible solar module can be bent to a bending radius of 7 mm showing relatively good bending capability. Neutral plane analysis was also indicated that the flexibility of the solar module can be further improved by locating the solar cell in the neutral plane.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.14-19
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• 2007

This study was conducted to analyze the antioxidant activity and xanthine oxidase inhibitory effect of hot-water extracts from Elaeagnus multiflora Thunb. to provide fundamental data for the development of functional materials. The antioxidative activities of hot-water extracts from E. multiflora Thunb. were analyzed by electron donating ability (EDA) using 1,1-diphenyl-2-picryl hydrazyl (DPPH), superoxide dismutase (SOD) -like activity by pyrogallol and nitrite scavenging ability. EDA of extracts from unripe, ripe, and overripe fruits were 77.7%, 36.0%, and 23.7% at 100 ${\mu}g/mL$, respectively, and EDA of extract in unripe fruits was higher than those of others. At 1,000 $\mu$g/mL, the SOD-like activities were 32.8%, 11.2% and 5.0% for unripe, ripe, and overripe fruits, respectively. The SOD-like activity was increased along with the increase of unripe and ripe extract concentrations. The nitrite scavenging ability of unripe fruit extracts in 100, 300, 500 ${\mu}g/mL$ of extraction solution in pH 1.2 and 3.0 was higher than those of others. The nitrate scavenging ability of all extracts was decreased according to the increase of pH. Xanthine oxidase inhibitory activities of unripe, ripe and overripe fruits were 30.0%, 28.2%, and 18.2% at 1,000 ${\mu}g/mL$, respectively.

• Microbiology and Biotechnology Letters
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• v.47 no.1
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• pp.148-157
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• 2019

A 70% ethanol extract of Erigeron annuus (L.) Pers. was investigated for its whitening activity for application as a functional ingredient in cosmetic products. At the E. annuus extract concentration of $100{\mu}g/ml$, the electron-donating ability was found to be 67.83%, the tyrosinase inhibitory effect (related to skin-whitening) was 69%, the elastase inhibitory effect (related to skin-wrinkling) was 69%, and the astringent effect was 80%. The $ABTS^+$ radical-scavenging ability was 87% at the $500{\mu}g/ml$ concentration. In the cell viability test measured on melanoma cells, 96% of the cells treated with $100{\mu}g/ml$ of the extract were viable. According to the western blot results, the protein expression of the microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 was decreased by 60.22%, 47.83%, 54.79%, and 67.88%, respectively, at the extract concentration of $100{\mu}g/ml$. The protein expression of phosphorylated extracellular signal regulated kinase (p-ERK) and phosphorylated cAMP response element-binding protein (p-CREB) was decreased with increasing concentrations of the extract. Reverse transcription-polymerase chain reaction of the extract showed that the mRNA expression of MITF, tyrosinase, TRP-1, and TRP-2 was decreased by 86.51%, 85.22%, 74.26%, and 66.66%, respectively, at $100{\mu}g/ml$ extract concentration. The findings suggest that the 70% ethanol extract from E. annuus (L.) Pers. has potential as a cosmeceutical ingredient with whitening effect.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.337-346
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• 2022

The purpose of this study was to investigate the antioxidant and anti-inflammatory activities of hot water (AMPW) and 70% ethanol (AMPE) extracts of apple mango (Mangifera indica L.) peel. The antioxidant activities were measured using a total polyphenol, electron-donating, 2,2'-azinobis [3-ethylbenzothiazoline6-sulfonic acid] (ABTS) radical scavenging assay. The total polyphenol content of AMPW and AMPE was 66.08 ± 0.62 mg TAE/100 g and 100.13 ± 0.23 mg TAE/100 g, respectively. As a result of measuring the electrondonating ability, at a concentration of 1,000 ㎍/ml, AMPW and AMPE showed an effectiveness of 86% and 94%, respectively. The ABTS assay showed 80% and 98% respective radical scavenging activity for AMPW and AMPE, at a concentration of 1,000 ㎍/ml. The cell viability on macrophage cells was performed using a 3-[4,5-dimethyl-thiazol-2-yl]-2,5-diphenyl-tetrazoliumbromide (MTT) assay, and the results showed more than 90% cell viability at a 100 ㎍/ml concentration. Anti-inflammatory activity was verified by confirming nitric oxide (NO) production inhibitory activity, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) protein and mRNA expression inhibitory activity from lipopolysaccharide (LPS)-treated RAW 264.7 cells. The NO production inhibitory effects were measured using the Griess assay, which confirmed 45% and 40% inhibition after treatment with AMPW and AMPE, respectively. Moreover, the protein and mRNA expression of inflammatory-related factors iNOS and COX-2, decreased in a concentrationdependent manner. In conclusion, this study showed antioxidant and anti-inflammatory effects of Mangifera indica L. peel and revealed its promising potential for application as an antioxidant and anti-inflammatory agent.

• Microbiology and Biotechnology Letters
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• v.52 no.3
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• pp.255-263
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• 2024

In this study, antioxidant and anti-inflammatory activity was studied to confirm the value of kailan (Brassica oleracea L.) as a natural material for cosmetics. For this study measure the antioxidative activity, total polyphenol content was measured, and DPPH and ABTS scavenging activity assays were conducted. As a result of measuring the total polyphenol content of hot water extract of kailan (KRD) and 70% ethanol extract of kailan (KRE), it was found to contain 124.3 mg TAE/100 g and 144.1 mg TAE/100 g, respectively. As a result of DPPH and ABTS radical scavenging ability, it was confirmed that the efficacy was concentration dependent. After treating the cells with LPS, a stimulant, for 2 hours, an experiment was conducted by treating RAW 264.7 cells with KRD and KRE at concentrations of 10, 50, and 100 ㎍/ml. The nitric oxide production inhibitory activity of KRD and KRE showed an inhibitory effect of about 30% at a concentration of 100 ㎍/ml. Cells cultured for 18 hours after stimulant treatment were obtained and used in experiments. The cells obtained in this way were lysed, protein and mRNA were extracted, and the expression of inflammatory mediators' inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was confirmed. It was confirmed that the protein mRNA expression of iNOS and COX-2, measured through western blot and reverse transcription-PCR, was inhibited in a concentration-dependent manner. Based on this, it is judged that has the potential to be used as a natural material in cosmetics.