• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.83.2-83.2
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• 2010

최근, 원유 가격의 상승으로 인해 태양에너지에 대한 관심이 크게 증가되고 있다. 그러나 이러한 태양전지용 Si(SoG-Si)의 대부분을 차지하는 태양전지급 다결정 실리콘 원료를 대부분 수입에 의존하고 있는 실정이다. 이에 대한 기술적 대응으로서 최근에는 고비용의 기상법을 해결하기 위하여 야금학적인 정련법을 이용한 제조기술 개발이 세계적으로 주목받고 있으며, 야금학적 정련기술은 지적재산권에 관한 기술적 배타성을 제고 할 수 있을 뿐 만 아니라 기상법의 Si 대비 낮은 품위 에도 불구하고 태양전지용 실리콘의 사용가능성을 제시함으로서 활발한 연구와 함께 실용화기술로 대두되고 있다. 그러므로 본 연구는 기존 사용 중인 고가의 기상법 폴리실리콘 제조와 달리, 생산 가격경쟁력이 있는 규석광으로부터 고순도금속 및 태양전지급 폴리실리콘 생산 연속 종전기술을 개발하고자 하였다. 금속급 Si(이하 MG-Si)으로부터 경제적인 SoG-Si을 제조하기 위한 공정 개발을 일환으로 MG-Si 중 불순물인 P 원소를 효과적으로 정련할 수 있는 슬래그 정련기술 개발과 슬래그설계 기술개발을 기본목표로 설정하여 고찰하였다. 용융 Silicon과 슬래그계면에 설정되는 산소분압제어에 따른 슬래그의 P의 이온 안정성을 변화시킴으로서, MG-Si중 P를 분리제거를 기본개념으로 설정하였다. 염기성 산화물로 산소이온이 공급됨을 이용하여 염기도에 따른 분배비를 고찰한 결과, CaO의 활동도가 증가함에 따라 슬래그 중 $O^{2-}$의 활동도와 함께 phosphide 이온의 안정성이 증가함을 확인하였다. 그리고 슬래그로부터 실리콘 중 Ca의 용해도에 따른 분배비를 확인하기 위해 실험 후 Si에서 Ca의 성분을 분석한 결과, 실리콘 중 Ca 용해도는 염기도($a_{CaO}/\sqrt{a_{SiO_2}}$)의 증가와 함께 증가하였으며, Ca의 용해도 증가는 탈린능을 증가시킨다는 것을 알 수 있었다. 또한 수소분압을 변화시켜 인의 증기압변화 및 기화정련 효과를 알 수 있었으며, acid leaching을 통해 잔존해있는 불순물을 추가적으로 정련될 수 있는 가능성을 확인할 수 있었다.

• Journal of the Korean Chemical Society
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• v.32 no.1
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• pp.60-64
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• 1988

Synthesis and biological activity test are described for the (Z)-11-hexadecen-1-ol, (Z)-11-hexadecen-1-yl acetate, and (Z)-11-hexadecen-l-al, the sex pheromone of the diamond back moth, Plutella xylostella L.. Lithium acetylide was alkylated with 10-bromodecan-1-ol THP ether to give 11-hexadecyn-l-ol THP ether. 11-Hexadecyn-l-ol THP ether was stereoselectively reduced over Pd/BaSO4to yield (Z)-11-hexadecen-l-ol THP ether, which was in turn deprotected to provide (Z)-11-hexadecen-l-ol. (Z)-11-Hexadecen-l-ol was acetylated and oxidized to afford (Z)-11-hexadecen-1-yl acetate and (Z)-11-hexadecen-l-al, respectively. Biological activity test of the synthetic compounds, (Z)-11-hexadecen-l-ol, (Z)-11-hexadecen-1-yl acetate, and (Z)-11-hexadecen-l-al in the ratio of 0.1 : 5 : 5 was tested in the field using polyethylene capsules as containers. The numbers of moth trapped with pheromone vials were counted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.524-528
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• 2002

Green layer, Enteromorpha prolifera, is regarded as one of important materials for food processing in Korea. The acidic water-soluble polysaccharide (CPC-PS) isolated from the alga with hot water and cetylpyridium chloride was mainly constituted of rhamnose, xylose, uronic acid and sulfate. To determine the glycosyl-linkages and positions of sulfate by methylation, the CPC-PS was reduced and/or sulfates. A marked increase of glucose content in the reduced polysaccharide indicated that glucuronic acid was a major sugar in the polymer and sulfation was deduced to occur on O-3 of rhamnose and O-2 of xylose. According to the methylation analysis of the native, reduced, desulfated and reduced-desulfated polymers, CPC-PS mainly composed of 1,4- and 1,2,3-linked rhamnose 3-sulfate, 1,4-linked xylose 2-sulfate, 1,4-linked xylose and 1,4-linked glucuronic acid. Minor 1,4-linked rhamnose and 1,4,6-linked galactose residues were also detected.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.2
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• pp.313-321
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• 2000

This paper deals with a kind of the half-space interfacial problem in time domain, requiring the calculation of the horizontal electric field generated by a tiny impulsive current source located horizontally at the interface between an isotropic upper half-space and a uniaxially anisotropic lower half-space. With the Cagniard-de-Hoop method adapted for our interfacial case, we obtain the explicit-form solution for this electric field. We also investigate the impulse radiation in the radial direction. The impulse components of Dirac $\delta$-function type in transient waveforms are important for the understanding of the interfacial far-field characteristics. The uniaxial case is a generalization of the isotropic one, and the explicit solutions of the uniaxial problem in this paper reduce to the solutions of the isotropic problem if the anisotropy is removed.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.5
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• pp.352-357
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• 2009

Due to rapid consumption of hydrogen peroxide, large amount of hydrogen peroxide is required when Fenton reaction is applied to the contaminated soil. In this study, acetate was employed as a ligand of $Fe^{2+}$ to enhance the efficiency of removal of phenanthrene by securing the stability of hydrogen peroxide. 0.5 ${\sim}$ 3 times of acetate (2${\sim}$12mM) was added to compare with molar concentration of $Fe^{2+}$. Low initial concentration of hydrogen peroxide was 0.7% to eliminate side effect of removal efficiency. The results showed that hydrogen peroxide lifetime was lasted up to 72 hours, or more than 50 times of normal lifetime. Phenanthrene removal efficiency was improved up to 70% due to stabilized hydrogen peroxide. Ferrous ion was oxidized to ferric ion and oxidation-reduction was repeated during the reaction. Finally ferric ion was reduced to ferrous by $HO_2$. It was confirmed that, due to the influence of hydrogen peroxide, pH was acid region and it remained at the range of 4 ${\sim}$ 5 when 8 mM or more of acetate was added. Acetate which was used as the ligand of Fe was also decomposed by Fenton reaction. The decomposition time of acetate was slower than phenanthrene. Therefore, it was able to come to the conclusion that phenanthrene was superior to acetate at the competition for decomposition. Through the results of this study, it was able to identify the possibilities to improve the efficiency of Fenton reaction in the contaminated soil and its economic feasibility, and to move to more realistic technique through research expanded to neutral pH region.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.81-86
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• 2017

Alignment of 967 reference sequences of the typical 2-Cys peroxiredoxin family of proteins revealed that 10 amino acids were conserved, with over 99% identity. To investigate whether the conserved aspartic acid residues and serine residue affect the peroxidase and chaperone activity of the protein, we prepared yeast TSA1 mutant proteins in which aspartic acids at positions 75 and 103 were replaced by valine or asparagine, and serine at position 73 was replaced by alanine. By non-reducing SDS-PAGE, TSA1 and the S73A, D75V and D75N mutants were detected in dimeric form, whereas the D103V and D103N mutants were detected in various forms, ranging from high molecular-weight to monomeric. Compared with wild type TSA1, the D75N mutant exhibited 50% thioredoxin peroxidase activity, and the S73A and D75V mutants showed 25% activity. However, the D103V and D103N mutants showed no peroxidase activity. All proteins, except for the D103V and D103N mutants, exhibited chaperone activity at $43^{\circ}C$. Our results suggest that the two conserved aspartic acid residues and serine residue of TSA1 play important roles in its thioredoxin peroxidase activity, and D103 plays a critical role in its chaperone activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1640-1648
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• 2009

This study was carried out to investigate the antioxidant activity of bamboo (Sasa borealis) leaf extract by measuring electron donating ability, superoxide dismutase (SOD)-like activity, reducing power, and lipid peroxidation inhibitory activity. Two crude extracts by water or 70% EtOH and five fractions of n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous from the crude extract of 70% EtOH were prepared for this study. The crude extracts of water and 70% EtOH yielded 8.5% and 11.4%, respectively and the yields of n-hexane, chloroform, ethyl acetate, n-butanol, and aqueous fractions were 5.1% to 0.6%. Total polyphenol contents of the water and the 70% EtOH crude extracts were not significantly different; however, their total flavonoid contents were significantly greater in the 70% EtOH than in the water crude extract. Total polyphenol contents were the highest in chloroform fraction followed by ethyl acetate and n-butanol fractions and total flavonoid contents were the highest in ethyl acetate fraction followed by chloroform and n-hexane fractions. The two crude extracts as well as the five fractions showed election donating ability, SOD-like ability, reducing power, and lipid peroxidation inhibitory activity. Most of the antioxidant activities of each crude extract or fractions increased proportionally with the concentration. These results indicate that bamboo (Sasa borealis) leaf extracts show antioxidant activities due to its substantial content of polyphenol including flavonoid. Thus, it could be concluded that crude extracts by water or 70% EtOH and the fractions from the 70% EtOH extract, especially chloroform, ethyl acetate and n-butanol, would be useful as natural antioxidant substances.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.118-128
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• 1996

N-methyl, N-butyl and N,N-dibutyl chitosan derivatives were prepared by Schiff's base formation and hydrogenation in aqueous media. Furthermore quaternization of the chitosan derivatives was performed in N-methyl-2-pyrrolidone using methyl iodide to obtain water soluble cationic polyelectrolytes. It was confirmed that O-alkylation was occured as well as selective N-alkylation in these reactions. Chitosan and chitosan derivatives with quaternary ammonium iodide showed high flocculation power as the cationic flocculant. When tested on paper mill waste water, they showed high flocculation power, independing of pH range. The flocculation power was increased as the N-alkyl chain length was increased. Among them, N-butyl dimethyl chitosan ammonium iodide showed better flocculation power than chitosan. But, N,N-dibutyl-N-methyl chitosan ammonium iodide showed less flocculation powre than chitosan itself.

• The Journal of Natural Sciences
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• v.14 no.1
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• pp.7-24
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• 2004

We found new type of thiol peroxidase, fused with GRX.(TPx-GRX) The TPx-GRX exists in pathogenic bacteria including -. This protein was homogeneously purified from the E.coli recombinant overexpressing TPx-GRX. In the presence of a thiol-containing electron donor such as DTT, the purified TPx-GRX has potent the antioxidant to prevent the inactivation of GS by the MCO system, which is comprised of DTT, $Fe^{3+}$, and $O^2$. The antioxidant activity is much higher that other thiol peroxidase. The investigate the peroxidase activity of TPx-GRX, we directly measured the peroxidase activity of TPx-GRX toward peroxides in terms of the removal of peroxides in the presence of GSH. This result demonstrates that the peroxidase activity of TPx-GRX. These taken together results suggest that TPx-GRX is a new member of thiol peroxidase. These observations also suggest that in the pathogenic bacteria, TPx-GRX plays an important antioxidative role as a multiple array defence mechanism against oxidative stress.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.731-736
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• 2010

The purpose of this study was to evaluate selected functional compounds and biological activities of 11 different pepper cultivars grown in rain-shelter and field. The selected compounds were capsaicinoids, polyphenolic and vitamin C. Antioxidant activities were measured by ABTS radical scavenging activity, reducing power and metal chelating effect. Antiproliferative activity was assessed by the measurement of the inhibition of HCT116, MCF 7 and NCI-H460 cancer cell proliferation. The contents of capsaicin, dihydrocapsaicin, polyphenolics and vitamin C from 11 cultivars grown in field were 0.0~268.3 mg/100 g, 0~55.1 mg/100 g, 635~878 mg/100 g and 4.1~8.2 mg/g, respectively. There were significant differences in the content of selected compounds among the cultivars, although no significant difference in rain-shelter and field was detected. Similar to the results from the selected compounds, there was no difference in antioxidant and antiproliferative activities between rain-shelter and field. This research provides basic information on functional compounds and biological activity of cultivation methods and pepper cultivars.