• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권10호
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• pp.564-569
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• 2000

This paper analyzed single AlGaAs/GaAa heterojunction energy band structures by solving Schr dinger's equation and Poisson's equation self-consistently. Four different concentrations, positively ionized donors, holes in the valence band, free electrons in the conduction band and 2DEG are taken into account for the whole system. 2DEG from both of the structures are obtained and compared with the date available in the literatures. Differential capacitances are also calculated from the concentration profiles obtained to prove the validity of the single AlGaAs/GaAs system. Finally, theoretical predictions for both of 2DEGs and the capacitances show good agreement with the experimental data referred in this study. It has only an error of les than 10 percent.

• 한국의류학회지
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• 제28권2호
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• pp.303-311
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• 2004

The purposes of this study were to investigate characteristic changes on nonwoven fabric by the charcoal printing. It separate grind charcoal as two different size of particles 45-52${\mu}{\textrm}{m}$ and 53-65${\mu}{\textrm}{m}$ for hand screen printing on three kind of nonwoven fabrics. To examine the effect of charcoal printing on nonwoven fabric were to obselve surface changes by a scanning electron microscope, dyeability by using spectrophotometer, moisture regain by oven method, air permeability, anion property, deodoriration and antibacterial activity. The results were as follows： When charcoal powder concentration increased from 3 to 9％, K/S value also increased from 3.06 to 8.55. When charcoal concentration increased, moisture regain also increased. In same concentration, moisture regain occurred higher as particle of small size. Air permeability decreased when the charcoal printing concentration increased. Anion occurrence appeared 140-160ion/cc from three different kinds of nonwoven fabrics in 3％ and 9％ charcoal concentration. Therefore, occurred anion ineffectively. In concentration of 3％, rate of deodorization measured as 89％, 83％ and 87％, and 9％ concentration caused 96％, 86％ and 93％ of high deodorization. Antibacterial activity examination in nonfinished nonwoven fabric resulted range of 60％, however, 3％ and 9％ concentration finished nonwoven fabric resulted 99.9％ of excellent antibacterial activity.

• 대한한의학방제학회지
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• 제9권1호
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• pp.335-354
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• 2001

This study was designed to investigate biological activity of antler extract added medical plants. The scavenging activity of DPPH radical was low scavenging activity at 0.01% concentration. But in the 0.05% and higher concentration, electron donating ability(EDA) is above 50% except Kongindangagam(48.5%) and significantly good above 70% in the 4 extracts. Superoxide dismutase(SOD)-like activity was 44.3% and 45.1% extracts of Ohjayenjongwhangami and M(market sample), Inhibition of xanthine oxidase were above 50% at 0.5% concentration except Boshingiwhangwhangami and from 62.4% to 84.9% in the 4 extracts. Inhibition rate of boshingiwhangwhangami was hasty increased from 33.5% to 77.5% at 1.0% concentration and others the higher concentration, the more increasing inhibition. Angiotension I-converting enzyme(ACE) inhibitory activities were high activity all of extracts. In the 0.5% concentration, ACE inhibition was above 80%. Especially 0.01% concentration of M was presented 81.8%. The study which conducted to investigate the effect of feeding antler extract group for 50 days on sperm concentration, Ca contents of serum, kidney and femur in rats was higher than that saline group.

• 동아시아식생활학회지
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• 제21권1호
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• pp.68-73
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• 2011

머루와인의 pH는 $3.7{\pm}0.1$, 총 안토시아닌 함량은 $4.3{\pm}0.3$, 색도는 $10.2{\pm}0.8$이었으며, 총 페놀과 플라보노이드의 함량은 각각 $18.8{\pm}3.9$ mg/100 g, $0.5{\pm}0.2$ mg/100 g이었다. 무기질은 총 10종이 검출되었으며, 특히 K의 함량이 $5.3{\pm}0.2$ mg/100 g으로 가장 높은 함량을 보였다. 전자공여능을 측정한 결과, 1,000 ${\mu}L/mL$의 농도에서 $90.4{\pm}1.8%$로 가장 활성이 뛰어났으며, 환원력을 측정한 결과, 농도가 1,000 ${\mu}L/mL$일 때 환원력은 0.932를 나타내었다. 그리고 아질산염에 대한 소거능을 측정한 결과, pH 1.2의 조건일 때 1,000 ${\mu}L/mL$의 농도에서 $76.3{\pm}1.3%$로 가장 뛰어난 소거능을 보였다. 머루와인의 농도가 증가함에 따라 실험 결과는 유의적으로 증가하는 경향을 보였다.

• Journal of Oral Medicine and Pain
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• 제20권2호
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• pp.429-447
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• 1995

This study was designed to determine the most effective concentration of fluoride and levels of laser irradiation for the remineralization of decayed teeth. After irradiation with a pulsed Nd:YAG laser and the topical application of fluoride, phosphate and fluoride concentration in enamel were measured. And then the changes on surface enamel using an scanning electron microscope were observed. Samples by extraction healthy, permanent, mandibular bovine teeth with no caries were obtained. Among them 371 healthy samples were selected and artificial carious lesions were made. 20 samples were assigned to each experimental group. After irradiation with a pulsed Nd:YAG laser with total energy densities of 10J/$\textrm{cm}^2$, 20J/$\textrm{cm}^2$ for each group. On the teeth, 2% NaF, 1.9% NH4F, 1.6% TiF4 Elmex gel(amine fluoride) and 1.23% APF gel were applied. After pH circulatory procedures, concentrations of fluoride with and Ionalyzer (Orion Research, Model 901, USA) and phosphates with an Uv/V is spectrophotometer (Uvikon 860, Kontrom Co, Switzerland) were measured. By etching the teeth in layers and measuring fluoride concentrations, a profile of fluoride penetration according to depth could be developed. And also the changes on the surface of the enamel using an electron scanning microscope were observed. The comparative analysis yielded the following results : 1. Phosphate concentration was low in all groups compared with the control group except for teeth treated Elmex gel, irradiated with 10J/$\textrm{cm}^2$ and 30J/$\textrm{cm}^2$ energy densities. Teeth treated with APF gel and 30J/$\textrm{cm}^2$ irradiation gad the lowest phosphate concentration. 2. Among all groups, fluoride concentrations in tooth enamel were highest in APF gel and NaF groups irradiated at 30J/$\textrm{cm}^2$. The APF gel group had the highest fluoride concentrations across all energy densities. 3. In the APF gel group, and the NaF group, the greater the energy density of the laser, the higher the fluoride concentrations in the enamel. 4. In all groups, the concentration of fluoride in the enamel by depth tended to decrease with depth. 5. Under the scanning electron microscope, under the condition of irradiation with 20J/$\textrm{cm}^2$, enamel crack was detected for the first time. In the NH4F group, spherical deposits were found on the surface of the enamel, and in the TiF4 group the surface of enamel was covered with an irregular, thin membranous mass in places. In the APF gel and NaF groups irradiated with 10J/$\textrm{cm}^2$, spherical and irregular particles covered the teeth. When these groups were irradiated at 20J/cm2, they were covered with amorphous crystals. These results suggest that one could obtain more effective anticariogenic effects without damage to teeth when less than 20J/$\textrm{cm}^2$ energy densities and APF gel are used.

• 한국조리학회지
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• 제16권4호
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• pp.297-304
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• 2010

머루 주스의 총 안토시아닌 함량은 $17.0{\pm}0.1$, 색도는 $33.9{\pm}1.4$였으며, 총 페놀과 플라보노이드의 함량은 각각 $25.4{\pm}3.1$ mg/l00 g, $4.4{\pm}1.4$ mg/100 g이었다. 무기질은 특히 K의 함량이 $11.3{\pm}0.3$ mg/100 g으로 가장 높은 함량을 보였다. 전자공여능을 측정한 결과 $1,000\;{\mu}L$/mL의 농도에서 $94.8{\pm}1.2%$의 뛰어난 전자공여능을 보였다. 머루 주스를 이용하여 금속이온의 환원력을 측정한 결과, 농도가 $1,000\;{\mu}L$/mL일 때 환원력은 1.134를 나타내었다. 그리고 아질산염에 대한 소거능을 측정한 결과, pH 1.2의 조건일 때 $1,000\;{\mu}L$/mL의 농도에서 $77.1{\pm}1.1%$로 가장 뛰어난 소거능을 보였다. 머루 주스의 농도가 증가함에 따라 실험 결과는 유의적으로 증가하는 경향을 보였다.

• 한국식품과학회지
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• 제42권2호
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• pp.250-255
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• 2010

본 연구에서는 야생 식 약용식물들을 새로운 기능성 소재로 개발하기 위한 연구의 일환으로 메꽃 잎의 물(WE)과 에탄올(EE) 그리고 열수 추출물(HWE)에 대한 xanthine oxidase 저해, SOD 유사활성, 아질산염 소거, 전자공여능 그리고 총 폴리페놀과 플라보노이드 함량을 측정하였다. 메꽃 잎의 세가지 추출물은 0.5 mg/mL에서 90% 이상의 xanthine oxidase 저해율을 나타내었으며, 고농도에서는 항산화제로 사용되는 BHA나 아스코르브산과 유사한 xanthine oxidase 저해효과를 나타내었다. SOD 유사활성은 HWE 추출물이 1.0 mg/mL에서 18%의 활성을 나타내었다. 아질산염에 대한 소거능을 측정한 결과에서는 1.0 mg/mL의 pH 1.2에서 세가지 추출물 모두 약 65% 이상, pH 3.0의 조건에서는 50% 이상의 소거능을 보였으며, WE가 가장 높은 아질산염 소거율을 나타내었다. 전자공여능은 0.1 mg/mL에서 EE가 84.80%로 가장 높았으며, 세가지 추출물 모두 저농도에서 가장 우수한 활성을 나타내었고, 추출물의 농도가 증가할수록 전자공여능이 감소하였다. 그리고 EE는 179.89 mg/g의 폴리페놀과 40.68 mg/g의 플라보노이드 화합물을 함유하였다. 이상의 결과 메꽃 잎은 우수한 생리활성과 다량의 폴리페놀과 플라보노이드를 함유하므로 이를 이용한 식음료나 기능성 가공식품, 식품 보존제 개발에 유용하게 활용될 수 있는 기능성 소재인 것으로 생각된다.

• 한국물환경학회지
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• 제21권4호
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• pp.403-409
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• 2005

Methyl tert-butyl ether (MTBE) contamination in groundwater often coexists with benzene, toluene, ethylbenzene, and xylene (BTEX) near the source of the plume. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by BTEX and MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc. In oil-contaminated environments, anaerobic biodegradation of BTEX and MTBE depended on the concentration and distribution of terminal electron acceptor. In this study, effect of electron acceptor on the anaerobic biodegradation for BTEX and MTBE-contaminated soil was investigated. This study showed the anaerobic biodegradation of BTEX and MTBE in two different soils by using nitrate reduction, ferric iron reduction and sulfate reduction. The soil samples from the two fields were enriched for 65 days by providing BTEX and MTBE as a sole carbon source and nitrate, sulfate or iron as a terminal electron acceptor. This study clearly shows that degradation rate of BTEX and MTBE with electron acceptors is higher than that without electron acceptors. Degradation rate of Ethylbenzene and Xylene is higher than that of Benxene, Toluene, and MTBE. In case of Benzene, Ethylbenzene, and MTBE, nitrate has more activation. In case of Toluene and Xylene, sulfate has more activation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.283-283
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• 2011

The n-doping effect by doping metal carbonate into an electron-injecting organic layer can improve the device performance by the balanced carrier injection because an electron ohmic contact between cathode and an electron-transporting layer, for example, a high current density, a high efficiency, a high luminance, and a low power consumption. In the study, first, we investigated an electron-ohmic property of electron-only device, which has a ITO/$Rb_2CO_3$-doped $C_{60}$/Al structure. Second, we examined the I-V-L characteristics of all-ohmic OLEDs, which are glass/ITO/$MoO_x$-doped NPB (25%, 5 nm)/NPB (63 nm)/$Alq_3$ (32 nm)/$Rb_2CO_3$-doped $C_{60}$(y%, 10 nm)/Al. The $MoO_x$doped NPB and $Rb_2CO_3$-doped fullerene layer were used as the hole-ohmic contact and electron-ohmic contact layer in all-ohmic OLEDs, respectively, Third, the electronic structure of the $Rb_2CO_3$-doped $C_{60}$-doped interfaces were investigated by analyzing photoemission properties, such as x-ray photoemission spectroscopy (XPS), Ultraviolet Photoemission spectroscopy (UPS), and Near-edge x-ray absorption fine structure (NEXAFS) spectroscopy, as a doping concentration at the interfaces of $Rb_2CO_3$-doped fullerene are changed. Finally, the correlation between the device performance in all ohmic devices and the interfacial property of the $Rb_2CO_3$-doped $C_{60}$ thin film was discussed with an energy band diagram.

• 열처리공학회지
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• 제24권1호
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• pp.31-36
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• 2011

$TiO_2$ films were deposited on a glass substrate with RF magnetron sputtering and then surface of $TiO_2$ films were electron beam irradiated in a vacuum condition to investigate the effect of electron bombardment on the thin film crystallization, surface roughness and gas sensitivity for hydrogen. $TiO_2$ films that electron beam irradiated at 450eV were amorphous phase, while the films irradiated at 900 eV show the anatase (101) diffraction peak in XRD pattern. AFM measurements show that the roughness is depend on the electron irradiation energy. As increase the hydrogen gas concentration and operation temperature, the gas sensitivity of $TiO_2$ and $TiO_2$/ZnO films is increased proportionally and $TiO_2$ films that electron beam irradiated at 900 eV show the higher sensitivity than the films were irradiated at 450eV. From the XRD pattern and AFM observation, it is supposed that the crystallization and rough surface promote the hydrogen gas sensitivity of $TiO_2$ films.