• Bulletin of the Korean Chemical Society
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• 제31권7호
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• pp.1897-1901
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• 2010

Multi-wall carbon nanotube (MWNT)-modified glassy carbon electrodes (GCE) were prepared for simultaneous determination of rutin and quercetin. Microbial carbohydrates, $\alpha$-cyclosophorohexadecaose ($\alpha$-C16) and succinoglycan monomer M3 (M3) were doped into MWNTs to prepare a $\alpha$-C16-doped MWNT-modified GCE (($\alpha$-C16 + MWNTs)/GCE) and a M3-doped MWNT-modified GCE ((M3 + MWNTs)/GCE), respectively. The sensitivities of the ($\alpha$-C16 + MWNTs)/GCE to rutin and quercetin were 34.7 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$ and 18.3 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$, respectively, in a linear range of $2\sim8{\mu}M$ at pH 7.2. The sensitivities of the (M3 + MWNTs)/GCE was 2.44 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$ for rutin and 7.19 ${\mu}A\cdot{\mu}M^{-1}{\cdot}cm^{-2}$ for quercetin without interference.

• Advances in nano research
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• 제1권3호
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• pp.159-169
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• 2013

A preparation method for gadolinium compound (GdC) nanoparticles coated with silica ($GdC/SiO_2$) is proposed. GdC nanoparticles were prepared with a homogeneous precipitation method at $80^{\circ}C$ using $1.0{\times}10^{-3}$ M $Gd(NO_3)_3$, 0.5 M urea and $0-3.0{\times}10^{-4}$ M ethylenediarinnetetraacetic acid disodium salt dihydrate (ETDA) in water. As a result of preparation at various EDTA concentrations, GdC nanoparticles with a size as small as $40.5{\pm}6.2$ nm, which were colloidally stable, were prepared at an EDTA concentration of $2.0{\times}10^{-4}$ M. Silica-coating of the GdC nanoparticles was performed by a St$\ddot{o}$ber method at $35^{\circ}C$ using $1.0-10.0{\times}10^{-3}$ M tetraethylorthosilicate (TEOS), 11 M $H_2O$ and $1.5{\times}10^{-3}$ M NaOH in ethanol in the presence of $1.0{\times}10^{-3}$ M GdC nanoparticles. Performance of preparation at various TEOS concentrations resulted in production of $GdC/SiO_2$ particles with an average size of $106.1{\pm}11.2$ nm at a TEOS concentration of $5.0{\times}10^{-3}$ M. The gadolinium (Gd) concentration of $1.0{\times}10^{-3}$ M in the as-prepared $GdC/SiO_2$ particle colloid solution was increased up to a Gd concentration of 0.2 M by concentrating with centrifugation. The core-shell structure of $GdC/SiO_2$ particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated $GdC/SiO_2$ colloid solution showed images of X-ray and magnetic resonance with contrast as high as commercial Gd complex contrast agents.

• 한국양식학회지
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• 제10권4호
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• pp.449-456
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• 1997

담수산 윤충의 대량배양을 위한 기초연구의 일환으로 진해내수면연구소 야회사육지에서 micro-pipette을 이용하여 Brachionus calyciflorus를 분리하여, 피갑의 크기, 포란 수 등을 조사하였고, 온도별 배양시험을 수행한 결과 다음과 같은 결과를 얻었다. 1. 분리한 담수산 윤충인 B. calyciflorus 의 피갑의 크기는 두 가지로 S-type은 길이가 평균 $141.0\pm16.7\mu m$($110.1-182.5\mu m,\;n=44$),폭이 평균 $107.0\pm20.3 \mu m\;(75.3-152.3 \mu m, n=44$)이었으며, L-type은 길이가 $262\pm15.2\mu m(234.4-288.6 \mu m,\;n=20)$,폭이 $182.6\pm13.4\mu m \;(159.8-207.0\mu m, n=20)$이었다. 2. 배양시 개체당 포란수는 1개에서 11개까지 다양하였으며, 난의 장경은 대형난과 소형난으로 구분되었는데 S-type의 경우 1-2개 포란한 경우 장경 평균 범위가 85.7-107.8 $\mu m$ 이었으며 3개 이상 포란한 경우는 장경 평균의 범위가 55.1-65.2 $\mu m$이었다. 한편 L-type의 경우 1-3개 포란한 경우 장경 평균 범위는 104.9-121.8 $\mu m$로 대형이었고, 4개 이상 포란한 경우 62.8-89.1 $\mu m$ 범위로 소형난이어서 S-type의 난보다 비교적 큰 편이었다. 3. 온도별 실험구에서 최대 밀도에 도달한 시기는 4일째로 성장이 가장 양호한 실험구는 $25^{\circ}C$ 실험구로 평균 배양 밀도 583.9개체/$m\ell$로 최대이었으며, 22$^{\circ}C$ 실험구는 배양 밀도 421.3 개체/m$m\ell$로 최대 밀도에 달하였으며, $28^{\circ}C$ 실험구의 경우 배양 1일 후 평균 4.7개체/m$m\ell$로 급격히 감소한 후 3일째에는 3개체/m$m\ell$ 이하로 감소하여 성장이 극히 불량하여 배양조건으로 부적합하였다. 4. 일간 개체군 증가율은 $22^{\circ}C$ 실험구의 경우 배양 2일째에 가장 높아 0.802이었고, 다시 낮아진 다음 최대 밀도에 도달했던 4일째에 0.762로 회복되었으며, $25^{\circ}C$ 실험구의 경우 배양 3일째 0.964까지 점진적으로 높아진 후 감퇴되었다. 암컷 개체당 포란수는 $22^{\circ}C$ 실험구의 경우 배양 3일째 0.614로 가장 높았으며, $25^{\circ}C$ 실험구의 경우 배양 4일째로 0.772이었다.

• 대한본초학회지
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• 제27권2호
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• pp.53-59
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• 2012

Objectives : This study was undertaken to investigate the effects of the GGEx18 ethyl acetate fraction (EF) on lipid accumulation and gene expression of fatty acid-oxidizing enzymes using 3T3-L1 adipocytes, C2C12 skeletal muscle cells, and NMu2Li liver cells. Methods : PPAR${\alpha}$, AMPK and UCPs transactivation was examined in NMu2Li hepatocytes, C2C12 myocytes, and 3T3-L1 preadipocytes using transient transfection assays. Results : 1. Compared with control, EF significantly increased the mRNA expression of VLCAD in 3T3-L1 adipocytes. 2. Compared with control, EF (0.1 ${\mu}g/ml$) significantly inhibited lipid accumulation in 3T3-L1 adipocytes. 3. EF significantly increased the mRNA expression of AMPK${\alpha}$1, AMPK${\alpha}$2 and PPAR${\alpha}$ in C2C12 skeletal muscle cells compared with control. 4. EF significantly increased the mRNA expression of genes involved in fatty acid ${\beta}$-oxidation, such as thiolase, MCAD, and CPT-1 in C2C12 skeletal muscle cells compared with control. 5. EF significantly increased the mRNA expression of UCP2 involved in energy expenditure in C2C12 skeletal muscle cells compared with control. 6. Compared with control, EF (10 ${\mu}g/ml$) significantly inhibited lipid accumulation in C2C12 skeletal muscle cells. 7. EF (10 ${\mu}g/ml$) significantly increased the mRNA expression of ACOX, HD, VLCAD and MCAD in NMu2Li liver cells compared with control. Conclusions : These results suggest that EF may prevent obesity by increasing the mRNA expression of mitochondrial fatty acid ${\beta}$-oxidizing enzymes in 3T3-L1 adipocytes, by not only regulating the fatty acid oxidation through activation of AMPK and PPAR${\alpha}$, but also increasing the UCP2 mRNA expression in C2C12 skeletal muscle cells, and by stimulating the mRNA expression of fatty acid-oxidizing enzymes in NMu2Li liver cells.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1165-1166
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• 2006

An experiment was carried out to investigate the effect of Ba Stearate as a reducing agent on the magnetic and physical properties of anisotropic $BaFe_2-W$ type ferrite magnets. It was found that the magnetic properties of $BaO{\cdot}8.5Fe_2O_3$ were improved by adding 0.3 wt% of Ba Stearate, 0.5 wt% of $SiO_2$, and 0.5 wt% of CaO together. The optimum conditions for making magnets were as follows; semisintering condition: $1350^{\circ}C{\times}4.0$ h in nitrogen gas atmosphere, drying condition: $180^{\circ}C{\times}2.0$ h in air, sintering condition: $1160^{\circ}C{\times}1.5$ h in nitrogen gas atmosphere. Magnetic and physical properties of a typical sample were $J_m$ = 0.46 T, $J_r$ = 0.43 T, $H_{cJ}$ = 182.3 kA/m, $H_{cB}$ = 177.2 kA/m, $(BH)_{max}$ = 33.8 kJ/$m^3$, $T_C$ = $495^{\circ}C$ and $K_A$ = $2.65{\times}10^5\;J/m^3$ and $H_A$ = 1332 kA/m.

• 천문학회지
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• 제26권1호
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• pp.73-78
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• 1993

We have mapped the $C_3H_2\;2_{12}-1_{01}$ transition line toward the Sgr A molecular cloud on a 1' grid spacing and derived $C_3H_2$ column densities of $3\~7\times10^{14}\;cm^{-2}$ for molecular clouds of Sgr A. The fractional abundances of $C_3H_2$ relative to $H_2$ are obtained to be $3\~6\times10^{-9}$, which are slightly lower than that for the cold dark cloud TMC-1 but are enhanced by factors of 5-60 compared to those for Sgr B2 and the Orion extended ridge. We also estimate from the $C_3H_2$ column densities total masses of $\~10^6\; M_\bigodot$ for two clouds (M - 0.13 - 0.08 and M - 0.02 - 0.07), which are thought to be close to the virial equilibrium. We suggest that the large abundance of $C_3H_2$ in Sgr A may be partly due to the activities of the Galactic center.

• 한국재료학회지
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• 제8권7호
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• pp.607-612
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• 1998

다합금계백주철의 성분원소인 Cr, V, Mo 및 W 의 첨가량을 변화시켜 응고조직을 관찰하였다. MC탄화물은 초정 austenite dendrite 내에 괴상 및 구상으로 M7C3탄화물은 intercellular boundary에 꽃형태 또는 bar 형태로, 그리고 M2C 탄화물은 M7C3탄화물과 마찬가지로 intercellular boundary에 침상으로 정출하였다. 기지조직은 주방상태에서 pealite 또는 (pearlite + austenite)의 혼합조직으로 구성되어 있었으며, 또한 EPMA 분석결과 MC탄화물은 V, M7C3 탄화물은 Cr 그리고 M2C탄화물은 Mo 및 W가 주성분으로 되어 있음을 알 수 있었다. 냉각곡선을 측정한 결과 액상에서 MC, M7C3, M2C 순으로 공정반응이 일어나고 있었으며 또한 X-선 회절시험을 통해 각 탄화물의 회절 peak를 관찰하였는바 응고조직의 사진과 잘 일치하고 있음을 알 수 있었다.

• E2M - 전기 전자와 첨단 소재
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• 제9권10호
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• pp.1047-1052
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• 1996

In this study, the thermal and optical proper-ties of multicomponent oxide glass fiber for IR sensor by adding heavy metal oxide Ga$_{2}$O$_{3}$ were investigated. The fiber samples were made by rod-in tube method. The optical loss of fiber was measured in 0.3-1.8/M wavelength region. As Ga$_{2}$O$_{3}$ increased up to 12wt%, the transition and softening temperature of bulk glass were increased from 495.deg. C to 564.deg. C and from 548.deg. C to 612.deg. C respectively. Whereas the thermal expansion coefficient was decreased from 102 to 88.2*10$^{-7}$ /.deg. C. The refractive index was increased from 1.621 to 1.662, and IR cut-off wavelength was enlarged from 4.64.mu.m to 5.22.mu.m. The optical loss of fiber was decreased and more remarkably decreased in 1.146.mu.m-1.8.mu.m wavelength region.

• Ecology and Resilient Infrastructure
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• 제7권4호
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• pp.308-319
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• 2020

본 논문은 경북 영천시 서문보에 최근 건설된 다기능 어도의 현장 적용성을 검토하기 위해 해석 변수를 R/C Slab (S1), R/C+S/C Slab (S2) 및 지하이동통로 규격 (가로 × 세로)을 1.4 × 0.2 m, 1.4 × 0.3 m, 1.4 × 0.6 m와 유속 0.8 m/s, 1.2 m/s, 1.6 m/s 으로 구분하여 해석한 결과 서문보 설계식 안전성을 평가하였다. 서문보의 설계식 보다 R/C+S/C Slab타입이 지하이동통로 출구부는 휨모멘트와 최대응력은 각각 16 - 33%, 24 - 32%, 측벽은 각각 17 - 33%, 20 - 36%, 상부슬래브인 경우도 19 - 33%, 9 - 28% 적게 나타났다. 따라서 최대응력과 휨모멘트가 R/C+S/C Slab 타입이 구조 안전성이 확보되는 것으로 나타났다. 따라서 지하통로는 휨모멘트와 최대 응력이 각각 14%, 18%, 측벽은 17%, 15% 상부슬래브는 16%, 11%의 보완이 요구되는 것으로 판단된다. 이러한 결과는 지하이동통로 규격이 서문보 규격과 동일한 1.4 × 0.3 m 일 때가 1.4 × 0.2 m, 1.4 × 0.6 m보다 안전성이 가장 유리한 것으로 확인되었다. 또한 해석 및 분석 결과를 근거로 서문보 규모의 다기능 어도 적용 시 기본 자료로 활용이 기대된다.

• 센서학회지
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• 제16권3호
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• pp.197-201
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• 2007

The magnetron reactive ion etching (RIE) characteristics of polycrystalline (poly) 3C-SiC grown on $SiO_{2}$/Si substrate by APCVD were investigated. Poly 3C-SiC was etched by $CHF_{3}$ gas, which can form a polymer as a function of side wall protective layers, with additive $O_{2}$ and Ar gases. Especially, it was performed in magnetron RIE, which can etch SiC at a lower ion energy than a commercial RIE system. Stable etching was achieved at 70 W and the poly 3C-SiC was undamaged. The etch rate could be controlled from $20\;{\AA}/min$ to $400\;{\AA}/min$ by the manipulation of gas flow rates, chamber pressure, RF power, and electrode gap. The best vertical structure was improved by the addition of 40 % $O_{2}$ and 16 % Ar with the $CHF_{3}$ reactive gas. Therefore, poly 3C-SiC etched by magnetron RIE can expect to be applied to M/NEMS applications.