• 공업화학
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• 제33권2호
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• pp.229-233
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• 2022

In this study, a gas-liquid hybrid atmospheric pressure plasma reactor of the dielectric barrier discharge method was fabricated and characterized. The solubility of copper oxide in the organic acid solution was increased when argon having a larger atomic weight than helium was used during plasma discharge. There was no significant effect of mixing organic acid solutions under plasma discharge treatment on the variation of copper oxide's solubility. As the applied voltage for plasma discharge and the concentration of the organic acid solution increased, the dissolution and removal power of the copper oxide layer increased. Solubility of copper oxide was more affected by the concentration in organic acid solution rather than the variation of plasma applied voltage. The usefulness of hybrid plasma reactor for the surface cleaning process was confirmed.

• 한국자원식물학회지
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• 제33권3호
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• pp.194-199
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• 2020

This study was carried out to get the information of Plum tree (192 germplasm) collected in Korea, and to evaluate the organic acid contents and fermentation solution. The organic acid content of fruit was 50.9 ± 6.0 mg/g, and which was composed of 55.5% of citric acid, 43.4% of malic acid and 1.1% of oxalic acid, and showed large difference among germplasms. Oxalic acid and malic acid made no differences in organic acid content according to flesh color, whereas citric acid and total organic acid contents were highest in orange color and lowest in whitish green. Malic acid, citric acid and total organic acid contents did not show differences among fruit weight groups, but oxalic acid content was highest at fruit weight of 5.1 ~ 10.0 g and lowest at more than 20.1 g. The sugar content of fermentation solution of fruit was 55.7 ± 1.6 °Brix and the harvest rate was 116.7 ± 8.7%. The correlation coefficients among fruit weight, the sugar content (°Brix) and harvest rate of fermentation solution were very low, and there were correlations of r=-0.551^⁎⁎ between fruit weight and oxalic acid, r=-0.767^⁎⁎ between malic acid and citric acid, and r=0.834^⁎⁎ between citric acid and total organic acid content.

• 공업화학
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• 제7권6호
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• pp.1204-1208
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• 1996

파라자일렌(p-xylene)을 산화반응시켜 테레프탈산(terephthatic acid)을 제조하는 과정 중에 발생하는 주요 유기불순물을 효과적으로 분석하는 방법을 수립하였다. 이 제조공정 중에 발생하는 유기불순물은 매우 다양하나, 여기에서는 주로 benzoic acid, p-toluic acid, p-tolualdehyde, 4-carboxybenzaldehyde, phthalic acid, isophthalic acid, trimellitic acid와 4-hydroxymethyl benzoic acid 등의 유기불순물을 분석하는데 촛점을 맞추었다. 이 유기물들은 공정 중의 모액이나 고체상태의 테레프탈산 입자에 존재하는데, 이들을 동시에 분석하기 위해 99% bis(trimethylsilyl)trifluoroacetamide와 1% trimethylchlorosilane의 내부표준용액과 pyridine의 혼합용액내에서 trimethylsilylation으로 시료를 전처리하고 gas chromatography를 이용하여 분석한 결과 상기한 유기물이 모두 성공적으로 분리되어 50분 이내에 정량분석할 수 있었다.

• 공업화학
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• 제10권6호
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• pp.907-912
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• 1999

본 연구는 유기산염 및 알칼리 원료를 사용해 야채 및 과일등에 잔류되어 있는 농약 및 유성오염의 제거효과를 GC와 세정력 측정장치를 사용해 조사했다. 일반적으로 잔류농약 등의 유성 오염원을 제거하기 위해서는 합성세제, 유기용제 등의 여러 방법이 있지만 본 연구에서는 특별히 식품첨가물 원료만 사용했다. 알칼리 수용액상에서 trisodium citrate를 사용했을때 가장 우수한 결과를 나타냈는데, 기존의 화학 합성세제와 비교했을 때 우수한 농약제거력이 나타났다.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.129-133
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• 1993

The effect of different compositions of organic acids on the flavor profile of 10% sugar solution was investigated by the response surface methodology, and the results were used to evaluate the flavor characteristics of lactic acid fermented cereal beverages. A mixture of extruded rice flour (10%) and soymilk (7.8% dry matter) was fermented with Leuconostoc mesenteroides (Sikhae). Depending on the substrate pretreatments, for example, the malt or amylase digestion and the proteolytic enzyme hydrolysis, the sugar and organic acid composition of the product varied. The organic acid composition of the fermented beverages was in the ranges of 0.44-0.55% lactic acid, 0.05-0.09% acetic acid and 0.07-0.09% citric acid, while that of commercial apple juice was 1.59% malic acid and 0.49% acetic acid. The flavor profiles of fermented beverages added with 10% sucrose were compared to those of apple juice and a model mixture containing 0.48% citric acid, 0.39% lactic acid and 0.12% acetic acid in 10% sugar solution. The QDA diagram of fermented beverages approached to that of apple juice, when the substrate was digested by amylase but not by protease.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.99-103
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• 2008

To improve efficiency of solar cells, it is important to make a light trapping structure to reduce surface reflectance for increasing absorption of sun light within the solar cells. One of the promising methods that can reduce surface reflectance is isotropic texturing with acid solution based on hydrofluoric acid(HF), nitric acid($HNO_3$), and organic additives. Anisotropic texturing with alkali solution is not suitable for multicrystalline silicon wafers because of its different grain orientation. Isotropic texturing with acid solution can uniformly etch multicrystalline silicon wafers unrelated with grain orientation, so we can get low surface reflectance. In this paper, the acid texturing solution is made up of only HF and $HNO_3$ for easy controlling the concentration and low cost compared to acid solution with organic additives. $HNO_3$ concentration and dipping time were varied to find the condition of minimum surface reflectance. Textured surfaces were observed Scanning Electron Microscope(SEM) and surface reflectance were measured. The best result of arithmetic mean(wavelength from 400 nm to 1000 nm) reflectance with acid texturing is 4.64 % less than alkali texturing.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.16-17
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• 2007

To improve efficiency of solar cells, it is important to make a light trapping structure to reduce surface reflectance for increasing absorption of sun light within the solar cells. One of the promising methods that can reduce surface reflectance is isotropic texturing with acid solution based on hydrofluoric acid(HF), nitric acid($HNO_3$), and organic additives. Anisotropic texturing with alkali solution is not suitable for multicrystalline silicon wafers because of its different grain orientation. Isotropic texturing with acid solution can uniformly etch multicrystalline silicon wafers unrelated with grain orientation, so we can get low surface reflectance. In this paper, the acid texturing solution is made up of only HF and $HNO_3$ for easy controling the concentration and low cost compared to acid solution with organic additives. $HNO_3$ concentration and dipping time were varied to find the condition of minimum surface reflectance. Textured surfaces were observed Scanning Electron Microscope(SEM) and surface reflectance were measured. The best result of arithmetic mean(wavelength from 400nm to 1000nm) reflectance with acid texturing is 4.64% less than alkali texturing.

• 한국토양비료학회지
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• 제45권5호
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• pp.760-763
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• 2012

친환경 포도재배를 위하여 농가에서 용이하게 구입 및 제조가 가능한 유기농자재의 효과를 조사한 결과 본 연구에 사용한 농자재의 pH는 4.6이하였고, 아미노산액은 상대적으로 높은 비료성분을 함유하였다. 포도수확기 토양의 pH는 시험초기 (농자재 처리 전)와 비교할 때 감소하였고, EC와 유기물함량은 증가하였으며, 유효인산은 대조구 (관행처리)를 제외하고 증가하였다. 치환성 K는 은행잎추출액 처리구와 대조구, 치환성 Ca는 무처리구와 아미노산용액 처리구에서 감소하였고, 치환성 Mg는 모든 농자재 처리구에서 감소하였다. 포도 잎의 질소 (N) 함량은 chitosan과 아미노산액 처리구, P는 chitosan, 목초액 및 아미노산액 처리구, K는 chitosan과 아미노산액 처리구, Ca은 chitosan 처리구, Mg 함량은 아미노산액 처리구에서 가장 높았다. 포도 수량은 목초액 처리구와 대조구에서 $1,581{\sim}1,583kg\;10^{-1}$로 가장 많았고, 당도는 무처리구를 제외하고 같은 수준을 보였다.

• 자원리싸이클링
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• 제28권6호
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• pp.36-45
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• 2019

석유화학공정에서 발생하는 폐촉매는 바나듐, 몰리브덴, 니켈, 코발트와 같은 희유금속을 함유하고 있다. 유기산에 의한 상기 금속의 침출에 대해 연구하였다. 본 논문에서 사용한 유기산에 의한 금속의 침출률은 옥살산 > 타르타르산 > 구연산 > 말레산 > 오스코브르산 순서이었다. 상기 유기산은 바나듐과 몰리브덴의 침출에 선택성이 있으며 옥살산에 의한 침출률이 가장 높았다. 옥살산의 농도, 반응온도, 광액밀도, 교반속도를 변화시켜 옥살산에 의한 바나듐의 최적침출조건을 얻었다. 옥살산에 의한 바나듐의 침출에 대한 속도식을 조사한 결과 Avrami식과 잘 맞았으며 활성화에너지는 8.76 kJ/mol로 물질전달에 의해 침출반응이 율속되었다.

• 보존과학연구
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• 통권16호
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• pp.112-122
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• 1995

TEN-STORIED STONE PAGODA ON THE SITE OFWON-GAKSA(Temple) which is one of three marble pagodas in South Korea, were dated from the thirteenth year of the reign of King Sejo(1467). On the roof and surface of each the stories, there were large amount of the contaminants such as pigeon′s excretions, dust and environmental elements for a long time. The pH of contaminants is not acid, but is 7.2, neutral. To find the species of organic acidscontained in the contaminants and the degree of damaging for a marble pagoda, we analyzed the contaminants using GC-MSD method by the following procedures. Organic acids were extracted by saponifying whole contaminants. After Saponification, the organic acids were mathylated to increase their volatility upon subsequent GC-MSD analysis. The mathyl esters of the organic acids are extracted from the acidified aqueous solution. And the organic extracts were washed with adilute base solution. The washed extract were analyzed by GC(Hewlett Packard 5890)with a nonpolar capillary column(Crosslinked 5% Ph Me Silicone, $50×0.2㎜×0.33\mum$film thickness, USA) and Mass Spectrometric Detector(Hewlett Packard 5970B).As the result, it was found that 12 organic acids were the main compound in pagoda′contaminants, and the amount of organic acid were negligible.