• Food Science and Biotechnology
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• 제18권6호
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• pp.1476-1480
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• 2009

Antioxidant activities of mulberry leaf extracted with different concentrations of EtOH were investigated. Total phenolic content and electron donating abilities of extract from 70% EtOH were the highest. Extracts obtained from EtOH-water mixture were shown to be significantly higher superoxide dismutase (SOD)-like activities than other treatment (p<0.05). Angiotensin-converting enzyme (ACE) inhibition was the greatest at 50% EtOH concentration (p<0.05). The extracts from 30-70% EtOH exhibited higher ferric reducing ability of plasma (FRAP) value than rest of the concentration (p<0.05). In case of nitrite scavenging activity, much higher scavenging activities were observed when the extraction was performed with EtOH or EtOH-water mixture (p<0.05). The results indicate that concentration of EtOH as extraction solvents can affect the antioxidant activity of mulberry leaf, which may provide useful information on the optimal solvent conditions for the extraction.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 추계종합학술대회
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• pp.613-616
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• 2001

공 부활제로 KCI, Cl, S 및 P를 각각 첨가한 발광충을 전자 빔 방법에 의해 성장시킨 2중 절연구조의 SrS:Ce electroluminescent(EL) device를 제작하여, 공 부활제가 EL device의 휘도에 미치는 영향을 조사였다. 휘도 및 발광파장은 첨가되는 공 부활제 및 농도에 의하여 상당한 영향을 받고 있음을 알았다. 어느 공 부활제에서나 전체 휘도는 0.2 mol%에서 최고를 나타냈으며, CeCl$_3$+KCL를 첨가한 소자가 최고 850cd/$m^2$를 나타내었다. 또한 CeP를 첨가한 소자의 경우 전체 휘도는 낮았으나 청색 휘도의 비율은 가장 높았으며, 이 비율은 농도의 상승에 따라 증가했다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.216-217
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• 2008

Zinc-oxide films were deposited by pulsed laser deposition (PLD) technique using doped ZnO target (mixed $In_2O_3$ 0.1, 0.3, 0.6 at. % - atomic percentage) on the p-type Si(111) substrate. A little Indium has added at the n-ZnO films for the electron concentration control and enhanced the electrical properties. Also, post thermal annealed ZnO films are shown an enhanced structural and controled electron concentration by the annealing condition for the hetero junction diode of a better emitting characteristics. The electrical and the diode characteristics of the ZnO films were investigated by using Hall effect measurement and current-voltage measurement.

• 한국재료학회지
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• 제18권3호
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• pp.117-122
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• 2008

Micro-sized bumps on a multi-layered build-up PCB were fabricated by pulse-reverse copper electroplating. The values of the current density and brightener content for the electroplating were optimized for suitable performance with maximum efficiency. The micro-bumps thus electroplated were characterized using a range of analytical tools that included an optical microscope, a scanning electron microscope, an atomic force microscope and a hydraulic bulge tester. The optical microscope and scanning electron microscope analyses results showed that the uniformity of the electroplating was viable in the current density range of $2-4\;A/dm^2$; however, the uniformity was slightly degraded as the current density increased. To study the effect of the brightener concentration, the concentration was varied from zero to 1.2 ml/L. The optimum concentration for micro-bump electroplating was found to be 0.6 ml/L based on an examination of the electroplating properties, including the roughness, yield strength and grain size.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.209-212
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• 2000

As a bench-scale study, transformation of nitrate to nitrogen gas under anoxic condition was determined by using autotrophic denitrifiers containing Thiobacillus denitrificans and elemental sulfur as an electron donor. The research objective is to measure the basic kinetic parameters of autotrophic denitrification reaction on the removal efficiency of nitrate. The results showed that nitrate was almost completely transformed to nitrite in the first 4 days of column operation. After 2 days of accumulation of nitrite, its concentration slowly decreased and the compound was detected less than 0.5 mg/L in 14 days. In the experiment, sulfate concentration in the effluent was the 70~90 mg-S/L and the pH was maintained around pH 7.5. When nitrate concentration of bank filtrate in the real field is considered, this sulfate concentration seems to be acceptable. At 17 cm from the bottom of the column, the effluent showed the highest nitrite concentration, and nitrate concentration decreased rapidly to the Point of 33 cm from the bottom. The results suggest that an appropriate thickness of permeable reactive barriers is about 30 cm.

• 한국표면공학회지
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• 제32권2호
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• pp.172-181
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• 1999

The effect of the DMAB concentration, temperature, deposition time, and stabilizer concentration on the precipitation reaction of the electroless nickel plating using dimethylamine borane (DMAB) as reducing agent was investigated to by the weight gain and electrochemical method. The deposition rate was dependent with DMAB concentration. The polarization resistance of the precipitation reaction was reduced with DMAB concentration. The precipitation reaction rate of Ni-B deposits was controlled by the oxidation rate of DMAB as the source of electron. The boron content of the deposit was constant at about 5.5wt%, even when DMAB concentration in the solution was increased. The effect of temperature and stabilizer ($Pb(NO_3)_2$) concentration on deposition rate was shown to have co-dependent behaviors.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.237-242
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• 2004

Recombinant human ferritin homopolymers (rHF and rLF) were successfully produced in the Saccharomyces cerevisiae Y2805, which was transformed with human ferritin H or L-chain genes, respectively. In order to characterize the molecular properties of the recombinant ferritins in relation to mineralization, the proteins were isolated and apoferritins were prepared. The apoferritins were reconstituted with 2000 Fe atoms per protein molecule under various experimental conditions (the concentration of the protein, the buffer concentration of the MOPS buffer, the total volume of the reaction and the reconstitution method). The structure and composition of the iron cores formed in the ferritins were examined using transmission electron microscopy. The recombinant ferritins behaved in a similar manner to other mammalian ferritins in accumulating iron in the core. Proteins of rHF and rLF showed varying reconstitution yields of 37-72% depending on the reaction conditions. In general, the rHF showed higher reconstitution yield than the rLF at the protein concentrations and the reaction volumes we examined. Iron cores with a similar mean particle size were obtained in the rHF, rLF and horse spleen ferritin reconstituted at a protein concentration of 1.0 mg/mL. Electron diffraction of all the three ferritins showed 2-3 diffuse lines, with d-spacings corresponding to those of the mineral ferrihydrite with a limited crystallinity.

• 한국재료학회지
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• 제20권6호
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• pp.294-300
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• 2010

In this study, we fabricated a polymer light emitting diode (PLED) and investigated its electrical and optical characteristics in order to examine the effects of the PFO [poly(9,9-dioctylfluorene-2-7-diyl) end capped with N,N-bis(4-methylphenyl)-4-aniline] concentrations in the emission layer (EML). The PFO polymer was dissolved in toluene ranging from 0.2 to 1.2 wt%, and then spin-coated. To verify the influence of the TPBI [2,2',2"-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)]electron transport layer, TPBI small molecules were deposited by thermal evaporation. The current density, luminance, wavelength and current efficiency characteristics of the prepared PLED devices with and without TPBI layer at various PFO concentrations were measured and compared. The luminance and current efficiency of the PLED devices without TPBI layer were increased, from 117 to $553\;cd/m^2$ and from 0.015 to 0.110 cd/A, as the PFO concentration increased from 0.2 to 1.0 wt%. For the PLED devices with TPBI layer, the luminance and current efficiency were $1724\;cd/m^2$ and 0.501 cd/A at 1.0 wt% PFO concentration. The CIE color coordinators of the PLED device with TPBI layer at 1.0 wt% PFO concentration showed a more pure blue color compared with the one without TPBI, and the CIE values varied from (x, y) = (0.21, 0.23) to (x, y) = (0.16, 0.11).

• 대한본초학회지
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• 제22권3호
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• pp.85-91
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• 2007

Objective : In this study, anti-oxidant and cosmeceutical activities of Isatis tinctoria L. extracted from water, ethanol and supercritical fluid condition were confirmed to investigate cosmeceutical activities for utilization as cosmetic ingredient. Methods: Anti-oxidant and cosmeceutical activities were investigated by using electron donating ability, xanthine oxidase, tyrosinase, astringent effect. Result : Isatis tinctoria L. extracts by supercritical fluid, water and ethanol showed good electron donating ability which were 82.7%, 62.6% and 44.8% at the concentration at 1,000ppm, respectively. Xanthine oxidase activity related with purine metabolism was inhibited by ethanol extract about 52.3% at the concentration at 1,000ppm. Tyrosinase inhibition effects, by supercritical fluid extract, ethanol extract and water extract, were 83.3%, 52.9% and 41.2% respectively at 1,000ppm. In the measurement of astringent effect, supercritical fluid extract at the concentration to 5,000ppm showed 85.7% in related activity. The water extract showed 95.9% nitrite scavenging activity at 5,000ppm. Conclusion : According to these results, it is possible that the extract of Isatis tinctoria L. can be used as a new natural material of cosmetic industry.

• 한국식품영양학회지
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• 제14권6호
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• pp.568-572
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• 2001

항산화 및 미백효과가 있는 생약재을 탐색하기 위해 생약재 70% 에탄을 추출물의 전자공여효과, 지질 과산화 억제효과 및 tyrosinase 억제효과를 검색하였다. 70% 에탄을 추출물의 전자공여 효과는 10$\mu\textrm{g}$/m1의 농도에서는 연교>홍화씨 >오미자>운지, 감초 순으로 나타났고 100$\mu\textrm{g}$/m1의 농도에서는 연교>운지 >감초>오미자>상지 >홍화씨 순으로서 연교의 전자공여효과가 가장크게 나타났다. 또한 l$\mu\textrm{g}$/ml에서 연교는 37%, 홍화씨는 31% 정도로서 매우 낮은 농도에서도 상당한 전자공여효과를 나타냈다. 지질과산화 억제효과는 쑥>감초>생지황>상지 순으로서 쑥이 가장 높은 항산화 효과를 나타내었고 tyrosinase 활성의 저해효과는 상지> 쑥> 느타리버섯 순으로서 상지가 가장 좋은 효과가 있음을 악 수 있었다. 위의 결과는 연교, 쑥 그리고 상지 등이 피부노화 억제 기능성 화장품의 소재로 이용될 수 있음을 시사한다.