• Composites Research
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• v.29 no.4
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• pp.145-150
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• 2016

Polyvinylidene fluoride (PVDF) as a representative polymer with the piezoelectric property has been studied since the 1960s. Crystalline structure of poly(vinylidene fluoride) polymer is composed of five different crystal structure of the polymer as a semi-crystalline. Among the various crystal structures, ${\beta}-type$ crystal exhibits a piezoelectricity because the permanent dipoles are aligned in one direction. Generally ${\beta}-form$ crystal structure can be obtained through the transformation of the ${\alpha}-form$ crystal structure by the stretching and it can increase the amount through the after treatment as poling process after stretching. ${\beta}-form$ crystal structure the PVDF fibers produced by wet spinning is formed through a diffusion mechanism of a polar solvent in the coagulation bath. However, it has a disadvantage that the diffusion path of the solvent remains as pores in the fiber because the fiber solidification occurs simultaneously with the diffusion of the polar solvent. These pores play a role in reducing effect of poling process owing to effect of disturbances acting on the polarization by the electric field. In this work, the drying method using the microwave was introduced to remove more effectively the residual solvent and the pore within PVDF fibers produced through wet-spinning process and piezoelectric PVDF fibers was produced by transformation of the remaining ${\alpha}$ form crystal structure into ${\beta}-crystal$ structure through the stretching process.

• Journal of Adhesion and Interface
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• v.25 no.2
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• pp.63-68
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• 2024

In this study, the contamination of gold(Au) wire according to the types of rinse applied for surface treatment in the wire bonding process is investigated and confirmed. For the surface treatment, rinses containing silicon(Si) or those based on organic materials are mainly employed. To identify their effects, surface treatment is conducted on Au wire using two types of rinse at a 1.0 wt% concentration, referred to as Si-including and Oil-based rinse-coated Au wire. Subsequently, a simulation experiment is performed to verify the reactivity of dust containing Si components that could occur in the semiconductor process. Through optical microscopy (OM) and scanning electron microscopy(SEM) analysis, it is observed that a larger amount of dust is adsorbed on the surface of Si-including rinse-coated Au wire compared with the Oil-based rinse-coated Au wire. This is attributed that the rinse containing Si components is relatively polar, causing polar interactions with dust, which also has polarity. Therefore, it is expected that using a rinse without Si components can reduce contamination caused by dust, thereby decreasing the defect rate in the practical wire bonding process.

• Korean Journal of Food Science and Technology
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• v.41 no.5
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• pp.547-551
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• 2009

Gromwell (LE, Lithospermum erythrorhizon), a perennial herbal plant, has been used for the treatment of various problems associated with atopic dermatitis of the skin, such as water loss, epidermal hyperproliferation, and severe inflammation. Previously, it was shown that oral supplementation with a 70% ethanol extract of gromwell prevented the development of atopic dermatitis in NC/Nga mice. In this study, in order to identify the fraction that mediates gromwell's efficacy, the dietary effects of water and ethyl acetate fractions from the ethanol extract of gromwell were assessed in the development of dermatitis using NC/Nga mice. Dietary supplementation of the hot water fraction significantly reduced scores for epidermal hyperproliferation in parallel with a marked increase of ceramides. Supplementation of the gromwell hot water fraction also decreased scratching behavior, which was accompanied by a decrease in plasma levels of IgE. These results showed that the hot water fraction of the gromwell ethanolic extract prevented the development of atopic dermatitis by increasing ceramides in NC/Nga mice.

• Journal of the Korean Chemical Society
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• v.33 no.3
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• pp.287-294
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• 1989

The optimum condition for the separation of priority pollutant phenols using isocratic elution has been determined. The elution behavior of eleven phenols has been also studied to interpret the retention. The reversed phase liquid chromatographic methods were performed on a ${\mu}$-Bondapak $C_{18}$ column with methanol-water, acetonitrile-water, and THF water mixtures as mobile phases. The COF method, where Snyder's solvent triangle concept was combined with a mixture-design statistical technique, was used to optimize the strength and selectivity of solvents for the separation of phenols. The optimum solvent composition, which gives a complete separation of eleven phenols, was found to be $MeOH:ACN:H_2O$ = 7:40:53. The plots of ln k' vs. -${\Delta}H^{\circ}$ and ${\Sigma}{\pi}$ of phenols showed relatively good linearities. Effect of van der Waals volume, pi-energy and hydrogen bonding on the retention of phenols were investigated. The following equation with the correlation coefficient of 0.9927 for ACN-water solvent system was obtained; $log^{k'}=2.515{\times}10^{-2}VWV-1.301{\times}10^{-1}E-3.674{\times}10^{-1}$

• Korean Journal of Food Science and Technology
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• v.52 no.2
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• pp.130-137
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• 2020

The present study was undertaken to compare the effects exerted by different extraction solvents on the extraction of active components, such as polyphenols and flavonoids, from the dried leaves of Artemisia annua L. Different extracts were prepared using a heating mantle. The extraction solvents used were distilled water, and 20, 40, 60, 80, and 99.5% ethanol solution. It was observed that the 40% ethanol solution yielded the most significant results in the extraction of various phytochemicals with phenol concentration of 154.8±0.28 mg of gallic acid equivalent/g and flavonoid content of 25.28±0.01 mg quercetin equivalent/g. However, based on the extraction solvent used, varying trends were observed in the antioxidant, enzyme inhibition, and bacterial inhibition analyses. It was concluded that the extraction solvent should be selected based on the purpose of use of the dried leaves of A. annua L.

• Journal of Oriental Neuropsychiatry
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• v.19 no.2
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• pp.223-230
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• 2008

소합향원 (蘇合香元) 가감방(加減方) 정유향기의 진통효과가 투여방법에 따라 어떤 차이가 있는지를 비교, 검토함으로서 본 약재의 새로운 적용방법을 탐색해 보고자 한다. 방법 : 가감소합향원에서 추출한 정유향기를 실험동물을 대상으로 7일간 경구 (50mg/kg, 100mg/kg), 흡입 (매일 3시간씩 1일 2회), 또는 피부도찰 (10mg) 방법으로 투여하여 페닐퀴논-유도 writhing test, 아세트산-유도 writhing test 및 hot-plate test를 실시하였다. 결과 : 가감소합향원 정유향기는 페닐퀴논-유도 writhing test에서는 피부도찰이 가장 효과적 이었으며 그 효과는 양성 대조약물인 아세트아미노펜 보다 약간 더 우수하였다 (p<0.05). 아세트산-유도 writhing test에서도 피부도찰법이 가장 좋은 효과를 나타내었으며 양성대조 약물인 아미노피린보다는 좀 더 좋은 효과를 보여주었다 (p<0.05). 그러나 hot-plate test에서는 경구투여가 가장 좋은 진통효과를 나타내었는데 고용량 (100mg/kg)에서는 양성 대조약물인 아세트아미노펜보다 유의적으로 더 효과적이었으나 저용량 (50mg/kg )에서는 이보다 다소 약하였다. 이상의 연구결과, 가감소합향원의 정유향기는 피부도찰시에는 비특이적 화학자극제인 페닐퀴논이나 아세트산에 의한 통증의 완화에 보다 효과적이며, 경구투여시에는 중추신경계에 영향을 미치는 hot plate에 의한 열자극성 통증에 더 유효함을 의미한다. 결론 : 가감소합향원의 정유향기액은 향기흡입보다는 피부흡수나 경구투여방법으로 진통의 목적으로 응용될 수 있을 것으로 사료된다.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.948-954
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• 2005

In this study, we investigated antimicrobial and cytotoxicity effects to each fraction extracted from Solanum lyratum (SL), which were extracted methanol (SLM) and then the extract was fractionated into five different types : hexane (SLMH), ethyl ether (SLMEE), ethylacetate (SLMEA), butanol (SLMB) and aqueous (SLMA). The antimicrobial activity was analyzed by the paper disc method. Among the various solvent fractions, SLMEA showed the strongest antimicrobial activies. The cytotoxicity of SL fractions on HeLa, MCF-7, HT-29 and HepG2 cells was evaluated by MTT assay. Among various partition layers, SLMEE showed the strongest cytotoxic effects to all cancer cell lines. We also observed that quinone reductase (QR) was induced by all fraction layers of SL to HepG2 cells. Since the QR-induced effects of SLMEE on HepG2 cells at $160{\mu}g/ml$ concentration showed 2.1 when compared with a control value of 1.0, inducer of QR for cancer protection may be contained in this fraction.

• Korean Journal of Plant Resources
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• v.32 no.4
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• pp.264-269
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• 2019

This research was performed to identify the anti-inflammatory constituent from the herb of Lycorus lucidus (Lamiaceae). The MeOH extract of this plant material and its two fractions, the lipophilic- ($CHCl_3$ fraction) and the hydrophilic fraction (BuOH fraction), were prepared to test anti-inflammatory activity. For this purpose, the inhibition rate on inducible nitric oxide synthase (iNOS) activity was assessed by determining nitric oxide (NO) formation in lipopolysaccharide (LPS)-induced macrophage 264.7 cells. The $CHCl_3$ fraction that greatly inhibited nitric NO formation was chromatographed to lead the isolation of ursolic acid. Since ursolic acid inhibited NO formation dose dependently in this study, this compound was considered as one of the active constituent responsible for anti-inflammation. However, the activity of rosmarinic acid isolated from the BuOH fraction was weak.

• Food Science and Preservation
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• v.9 no.1
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• pp.92-96
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• 2002

The nitrite-scavenging and antimutagenic effects of various solvent extracts from different parts of the loquat. were investigated to develope as source of functional food. The nitrite-scavenging and antimutagenic effects of fractions obtained from methanol extract were most highest in ethyl acetate fraction. Ethyl acetate fraction showed better results in the nitrite scavenging activity of 80% in leaf, 81% in seedless fruit, 73% in peel and 63% in seed. The antimutagenic effect showed strong ethyl acetate fraction of 53.1%, 48.3% in leaf and seedless fruit. The antimutagenic effect increased with increasing concentration of ethyl acetate fraction against mutagenicity induced by direct mutagen of IQ in Salmonella typhimurium TA 100. Addition of 2.5 mg and 5 mg of ethyl acetate fraction showed inhibitory effect of 65.5%, 71.2% in leaf and 63.4%, 69.2% in seedless fruit, respectively.

• Animal Systematics, Evolution and Diversity
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• v.1 no.1_2
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• pp.3-20
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• 1985

혹무늬 톡토기과의 56개 아과들에서 20개 형질복합을 추추랗여 형질평가방법과 Wagner algorithm의 형질 비평가방법을 사용하여 계통수를 작성, 비교하였다. 전자의 방법을 이해 진화적 형질순서와 극성을 결정하고 고등급의 파생공유 형질을 토대로한 단계통군과 자매군을 확인하여 계통분화를 추적하였다. 이 두가지 방법에 의한 계통수에서 분지 방식은 매우 다르게 나타났으나 나열순서는 유사했고, 단지 마지막의 2개 아과가 후자에서는 반대로 나타났다. 그 원인은 후자의 방법으로는 파생혈질수가 많은 분류군에서의 형질상태가 Wagner algorithm에서 누적효과를 일으킨 때문인 것으로 생각되며, 아울러 1, 10 및 20 번 형질의 적응이동(adaptive shift) 상 나타낼 중요한 의의를 적절히 평가 반영할 수 없는 것으로 추정된다.