• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.151-157
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• 2007

We have presented a compact two-wire helical antenna adopted an open stub in opposite to a feeding point, which is for a T-DMB antenna of mobile devices. By adjusting the length of the open stub or pasting a dielectric material on the open stub, the input impedance around 200 MHz, bands of the T-DMB, can be easily control, even though the total height of the antenna is less than 8 cm(0.053 $\lambda$ at 200 MHz). The operating mechanism of the antenna is explained by using equivalent circuits of two modes, an unbalanced mode and a balanced mode. Based on the analysis of the equivalent circuits, the effects of using the open stub are validated. Several proposed antennas have been fabricated and measured. One of the fabricated antennas has -10 dB impedance bandwidth of $196{\sim}204$ MHz(8 MHz) whose value covers one channel of the T-DMB(6 MHz). The measured $S_{21}$ of the antenna is -38.6 dB which is about 17 dB higher than that of a monopole antenna whose height is same with the proposed antenna.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.4 s.59
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• pp.209-217
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• 2006

Emulsion is a dispersion system among liquids which are not miscible together. There are numerous cosmetic raw materials which have different physicochemical properties. Therefore, emulsion technology is very useful in cosmetics. With the development of emulsifier, several emulsification technologies have been developed. Since HLB method by Griffin in 1950's, PIT method, gel method, and D-phase methods, etc, have been developed. Recently, the application of natural emulsifier and polymeric emulsifier increases in cosmetics in order to achieve enhanced safety and biocompatibility. Besides nano-emulsion, multiple-emulsion, liquid crystal emulsion, and Pickering emulsion have been developed and applied as means of differentiating appearance and texture of products and achieving enhanced delivery of active ingredients. Meanwhile, the application studies of nano-dispersed structural system such as liposome or cubosome are on progress. Liposome is a bi- or multi-lamella layer dispersion system composed of amhiphilic molecules - phospholipids which are main components of plasma membrane. Cubosome also is a nano-sized dispersion system composed of a specific molecule like glyceryl monoloeate derived from natural products. And it has a cubic bicontinuous structure in water due to its unique molecular structure. Incorporating compounds (active materials) into such nano-particles can increase biocompatibility and delivery efficiency of target compounds. Manufacturing process and application of cosmetic emulsions and nano-particles are briefly introduced in this paper.

• Fire Science and Engineering
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• v.30 no.5
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• pp.93-99
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• 2016

This study tested the combustion characteristics of veneer specimens coated with four kinds of ammonium salts. Each veneer specimen was coated three times with 20 wt.% ammonium salt solutions at room temperature. After drying, the combustion characteristics of the specimens coated with chemicals, were investigated using the cone calorimeter (ISO 5660-1, 2). The specimens coated with monoammonium phosphate (MAPP) and, diammonium phosphate (DMPP) showed a 6.7% and, 10.0%, lower mean heat release rate ($HRR_{mean}$), respectively, than that of the uncoated specimen. On the other hand, the specimens coated with MAPP showed a 15.7% higher $CO_{peak}$ production rate and the specimens coated with DAPP showed by 8.2% lower rate than that of the uncoated specimen. The veneer coated with ammonium sulfate (AMSF) and DAPP showed a 9.6% and 33.3% lower the peak smoke production rate ($SPR_{peak}$) than that of the uncoated specimen. In addition, the time to the peak smoke extinction area ($SEA_{peak}$) was delayed by 38.4% in the specimens coated with DAPP than the uncoated specimen. Therefore, DAPP inhibited the combustion properties of the veneer and showed a tendency to reduce smoke production.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.19-26
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• 2017

Effects of resveratrol glucosylation on the immunomodulation properties of resveratrol and on the viability of macrophage cells have been studied by using murine macrophage RAW 264.7 cells. Nitric oxide (NO) and interleukin 6 (IL-6) expression in macrophages in vitro were studied after treatment with different concentrations of (E)-resveratrol, (E)-resveratrol 3-O-${\beta}$-${\small{D}}$-glucoside (R-3-G), or (E)-resveratrol 4'-O-${\beta}$-${\small{D}}$-glucoside (R-4'-G). In vitro viability of RAW 264.7 cells after treatment with the aforementioned three compounds was also studied. As demonstrated by macrophage cell viability assays, two different resveratrol monoglucosides, R-3-G and R-4'-G, exhibited 50-80% reduced cytotoxicity in comparison to (E)-resveratrol in A549 and HepG2 cells. Compared to the resveratrol aglycon, both glucosylated resveratrol derivatives positively modulated NO and IL-6 production in macrophages positively via transcriptionally up-regulating IL-6 and iNOS expression. Conjugation of a glucose moiety on resveratrol was found to enhance the immunomodulating activity of resveratrol and the viability of RAW 264.7 cells.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1343-1351
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• 2010

In this paper, a novel patch antenna based on the metamaterial CRLH(Composite Right- and Left-Handed) structure is designed, implemented, and measured. Contrary to the standard microstrip patch's fundamental resonance mode of half-wavelength or its positive multiple, the proposed antenna shows the in-phase electric field over the entire antenna. The proposed antenna has a desired omni-directional field pattern which is typical characteristic of $\lambda/4$ monopole antenna, and also shows the merit of low profile. HFSS(High Frequency Structure Simulator) of Ansoft which is based on the FEM(Finite Element Method) is used to simulate the proposed antenna. FR-4 substrate of thickness 1.6 mm and relative permitivity 4.4 is used for the proposed antenna implementation. The implemented antenna showed VSWR (Voltage Standarding Wave Ratio)$\leq$2 for the frequency band from 2.63 GHz to 2.655 GHz which is used for S-DMB (Satellite-Digital Multimedia Broadcasting) service. And measured peak gain and efficiency are 2.65 dBi and 81.14 %, respectively.

• Journal of Korean Society of Forest Science
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• v.89 no.3
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• pp.384-388
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• 2000

For the control of Corythucha ciliata, the insecticidal activity of five commercial pesticides (Monocrotophos 25%SL, Phosphamidon 50%SL, Imidacloprid 20%DC, Thiamethoxam 15%DC and Acetamiprid 20%SL) were examined with trunk injection method in Seoul, Sanbon and Chungju. The insecticidal activity of five commercial pesticides was >88%. The insecticidal activity of Monocrotophos maintained 31 days later after trunk injection when treated leaves were supplied to this pest. This result indicates that one application of trunk injection is enough to control this pest, and this method can save the control cost compared with ground application which should be applied two or three times per year to control this pest. To make the model of treatment dosage at each D.B.H class (cm), $1.0m{\ell}/DBH$, $1.5m{\ell}/DBH$ and $2.0m{\ell}/DBH$ pesticide dosage was used. At <20cm, the insecticidal activity of $1.0m{\ell}$ dosage was >95%, and $1.5-2.5m{\ell}$ dosage was needed for the effective control at 30~50cm. More than $2.5m{\ell}$ dosage was effective at >50cm. Spray method was used in laboratory to select pesticides for ground application. Three commercial pesticides (Ethofenprox 20%EC, Ethofenprox 10%WP and Cyfluthrin 1%EC) were used, and all pesticides showed >95% insecticidal activity.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.302-308
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• 2015

Isothermal vapor liquid equilibria for the binary system of 3-methylpentane with ethylene glycol monopropyl ether ($C_3E_1$) and ethylene glycol isopropyl ether ($iC_3E_1$) were measured at 303.15, 318.15, and 333.15K. In our previous work, phase equilibria for the binary system of $C_3E_1$ mixtures were investigated according to the chain length of alkane, alcohol or those isomer. But in this study, we discussed the different effect of $C_3E_1$ and its isomer, $iC_3E_1$, on the phase equilibria. The measured systems were correlated with a Peng-Robinson equation of state (PR EOS) combined with Wong-Sandler mixing rule for the vapor phase, and NRTL, UNIQUAC, and Wilson activity coefficient models for the liquid phase. All the measured systems showed good agreement with the correlation results. And it was found that the phase equilibria showed very little difference between the $iC_3E_1$ mixture system and the $C_3E_1$ mixture system.

• Journal of the Mineralogical Society of Korea
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• v.23 no.2
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• pp.151-159
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• 2010

The effect of calcite and gypsum on the hydration of Portland cement was investigated using GEM-PSI, a geochemical model. Addition of calcite and gypsum up to 5 wt% of total cement clinker into Portland cement was found to influence the hydrate assemblage of the hydrated cement in different ways. The results of geochemical modelling showed that the fraction of calcium monocarbonate increased by the hydration of cement with the increase of calcite addition. The results of modelling also indicated that gypsum increased the fraction of ettringite in the assemblage of hydrated cement as the amount of gypsum added increases. This study showed that porosity generated by the hydration of cement had a significant relation with the amount of calcite and gypsum added. The porosity of hydrated cement was lower when calcite added up to 3 wt% of cement clinker compared to the hydrated cement with the same amount of gypsum addition. However, when calcite added more than 3% of cement clinker, the porosity of hydrated cement were higher than that of hydrated cement with the same amount of gypsum addition.

• Korean Journal of Microbiology
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• v.52 no.2
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• pp.157-165
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• 2016

Under flooded rice fields, methanogens produce methane which comes out through rice stalks, thus rice fields are known as one of the anthropogenic sources of atmospheric methane. Studies have shown that use of manure increases amount of methane emission from rice. To investigate mechanisms by which manure boosts methane emission, comparative soil metagenomics between inorganically (NPK) and pig manure fertilized paddy soils (PIG) were conducted. Results from taxonomy analysis showed that more abundant methanogens, methanotrophs, methylotrophs, and acetogens were found in PIG than in NPK. In addition, BLAST results indicated more abundant carbohydrate mabolisetm functional genes in PIG. Among the methane metabolism related genes, PIG sample showed higher abundance of methyl-coenzyme M reductase (mcrB/mcrD/mcrG) and trimethylamine-corrinoid protein Co-methyltransferase (mttB) genes. In contrast, genes that down regulate methane emission, such as trimethylamine monooxygenase (tmm) and phosphoserine/homoserine phosphotransferase (thrH), were observed more in NPK sample. In addition, more methanotrophic genes (pmoB/amoB/mxaJ), were found more abundant in PIG sample. Identifying key genes related to methane emission and methane oxidation may provide fundamental information regarding to mechanisms by which use of manure boosts methane emission from rice. The study presented here characterized molecular variation in rice paddy, introduced by the use of pig manure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.11 s.114
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• pp.1021-1029
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• 2006

In this paper, we designed and implemented a dual wideband dipole type antenna for the reception of S-DMB (Satellite Digital Multimedia Broadcasting) and 2.4/5 GHz WLAN(Wireless Local Area Network) signals. The proposed antenna based on conventional monopole type dual band antenna was implemented as planar wideband dipole type antenna with the volume of $8{\times}33.8{\times}1.68mm^3$. The proposed antenna is printed type on FR4 substrate of 1.6 mm thick and composed of a dipole type antenna for low frequency band and two symmetric structured resonance elements for high frequency band. We confirmed antenna area with dense surface current for each frequency band with simulation. By varying the length of the antenna area with dense surface current, we could vary resonance frequency of each frequency band separately. Impedance bandwidths$(VSWR{\leq}2)$ are 362 MHz(14.23 %) for 2 GHz band and 1188 MHz(22.13, %) for 5 GHz band which show wideband characteristic. Measured maximum gains were 4.33 dBi for 2 GHz band and 5.48 dBi for 5 GHz band which showed improved performance. And the implemented antenna has a good omni-directional radiation pattern characteristic.