• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1245-1253
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• 2014

One-step sulfuric acid saccharification of the red alga Pterocladiella capillacea was optimized, and various detoxification methods (neutralization, overliming, and electrodialysis) of the acid hydrolysate were evaluated for fermentation with the thermotolerant yeast Kluyveromyces marxianus. A proximate composition analysis indicated that P. capillacea was rich in carbohydrates. A significant galactose recovery of $81.1{\pm}5%$ was also achieved under the conditions of a 12% (w/v) biomass load, 5% (v/v) sulfuric acid, $121^{\circ}C$, and hydrolysis for 30 min. Among the various detoxification methods, electrodialysis was identified as the most suitable for fermentable sugar recovery and organic acid removal (100% reduction of formic and levulinic acids), even though it failed to reduce the amount of the inhibitor 5-HMF. As a result, K. marxianus fermentation with the electrodialyzed acid hydrolysate of P. capillacea resulted in the best ethanol levels and fermentation efficiency.

• 한국표면공학회지
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• 제43권4호
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• pp.187-193
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• 2010

The colored films formed on 304 stainless steel plates by immersion treatment and electrochemical one in a solution containing sulphuric acids and chromic acids were studied by SEM, AES, and spectrophotometer. The thicknesses of the films by 20 minutes treatment were about 200 nm and it became thinner as the treatment times were increased. The surface texture showed a tortuous network of interlinking pathways. The color of the 304 steel surface changed from metallic white to gray, black, red, yellow-green, and green-blue, gradually, by the treatment time was increased. The reflectivity measured by UV-VIS-NIR spectrophotometer was reduced from max. 38% of basis metal to min. 3.5% of colored surface.

• 분석과학
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• 제5권3호
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• pp.277-283
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• 1992

질산, 염산, 황산 그리고 질산과 염산의 1:1 혼산의 농도를 변화시키면서 유도결합 플라즈마 원자방출분광법(ICP-AES)의 신호크기에 미치는 산의 영향을 연구하였다. 거의 모든 측정원소의 신호크기가 감소되었다. 산의 존재로 인한 감소는 산 농도가 1% 이상 될 때 심하게 눈에 띄었고, 사용된 산 중에서 황산에 의한 감소가 가장 심했으며 그 정도를 예측하기 힘들었다. 산의 농도를 변화시키면서 측정 원소의 신호크기 대 Ar 신호크기의 비, 그리고 Mg II 신호크기 대 Ma I 신호의 비를 측정하였다. 이 연구에서, 신호크기 감소의 주된 원인은 플라즈마 들뜸특성의 변화에 의한 것이 아니고, 분무효율의 변화, 예를 들면 droplet 크기분포, 점도와 표면장략의 변화 등인 것으로 판명되었다. 유도결합 플라즈마 질량분석법(ICP-MS)에서는 신호크기의 감소와 이온화 에너지와의 상관관계는 발견되지 않았다.

• 한국위험물학회지
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• 제2권1호
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• pp.6-11
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• 2014

There have been frequent chemical leaks over the past 10 years. Particularly, inorganic acids like sulfuric acid, nitric acid, and hydrogen chloride take up 37 % of the total chemical accidents which took place for the past 10 years. When an acid chemical leak happens, fume is generated, diffusing into the air, which might cause serious damage to health of local residents and the environment. However, most of the acid-based chemicals, detecting and analysis methods have not been settled considering the frequency of accidents. In this study, we investigated detection and analysis methods to quickly analyze accident sites and evaluate the impacts on environments. Reviewing local and international test analysis methods of acids suggested that nitric acid, sulfuric acid, hydrogen chloride and hydrogen fluoride can be analyzed with IC. It was also found that UV is better for the analysis of hydrogen fluoride and GC/MS for acrylic acid. The analytical methods suggested in the official test methods basically have limitations of consuming much time at stages of preparation and analysis. Considering prompt responses to chemical accidents, further studies should be done to compare the applicability of rapid monitoring methods such as FT-IR, IMR-MS and SIFT-MS.

• 분석과학
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• 제11권4호
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• pp.311-315
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• 1998

Ultra trace metal impurities of high-purity sulfuric acid for semiconductor process have been determined in the concentration of lower than ppb (ng/g) level using high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS).The acid samples were evaporated and concentrated by the factor of 20. No clement in the acids exceeded 1ppb level and most of the clements were determined below 10ppt (pg/g). Elements without spectral interference in mass spectrum, such as In, V, Mn, etc, were determined in the concentration of below 1 ppt level The recoveries in the range of 72% to 127.2% for 0.5 ppb spiked sample were obtained.

• 한국식품영양학회지
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• 제12권5호
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• pp.496-501
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• 1999

Albinism is a phenomenon that color of the body surface is changed to white orfaint brown from the specific color to the species by difficiency of pigments due to mutation or disease. This study was undertaken to investigate the experimental basis on the appearance of albinism in cultured flounder Paralichthys olivaceus. The skin and muscle from the normal and albinic flounder were used by measuring contents of amino acid free amino acid. The results were summarized as follows: Contents of amino acid in theskin and muscle are different from normal and albinic flounder. Phenolic and sulfuric amino acids in the skin of normal flounder were 2 times those of albinic ones. Especially tyrosine contents of the skin in normal flounder were 24 times higher than those. Methionine was 26 times higher than those Phenylalanine was 1.6 times higher. In free amino aicd phosphoserine and phosphoethanolamine were a little higher than that ones. The melanin formation of the skin in flounder was affected by substrates such as phenolic amino acid and cofactor such as sulfuric amino acid.

• 한국환경농학회지
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• 제27권3호
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• pp.279-284
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• 2008

We investigated whether carboxylate exudation of Brassica pekinensis Rupr. was affected by nitrate deposition from simulated acid rain. A gas chromatographic (GC) analysis was employed for the determination of low molecular weight organic acids (LOA) in rhizosphere soils, bulk soil, roots and leaves of Brassica pekinensis Rupr.. Rhizosphere soils were collected after 8 weeks of plant growth by first removing the bulk soil from the root system and then by mechanical move off the rhizosphere soil that adhered to the root surface with soft brush. Soil and plant materials were simultaneously extracted with the mixture of methanol and sulfuric acid (100:7, v/v). Seven organic acids, oxalic, malonic, fumaric, succinic, maleic, L-malic and citric acid were identified and quantified by GC equipped with FID. Oxalic, L-malic, and citric acids were found in both the bulk and rhizosphere soils, while most LOAs were not detected in the control treatment. On the contrary, except maleic acid, all other organic acids were detected in the leaves and roots of cabbages treated with nitrate deposition.

• Journal of the Korean Wood Science and Technology
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• 제40권6호
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• pp.389-396
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• 2012

본 연구는 산 촉매에 의한 자이란 분해속도를 분석하는 것으로 $120^{\circ}C$에서 60분 동안 가수분해를 수행하여 자이란 분해속도를 조사하였다. 산 촉매로는 황산, 옥살산, 말레산을 사용하였다. 자이란 분해에 관여하는 분해속도상수($k_1$)는 산 농도에 비례하여 증가하였으며 이것은 산 농도가 증가할수록 자이란 가수분해가 빠르게 진행된다는 것을 의미한다. 황산, 옥살산, 말레산 중에서 자이란에서 자이로스로 분해되는 속도는 황산을 촉매로 사용하였을 때 가장 높았다. 하지만 수소농도인 pH를 기준으로 하였을 때, 즉 같은 pH 조건에서 가수분해를 수행하였을 때 자이란에서 자이로스로 분해되는 속도는 옥살산, 말레산과 같은 dicarboxylic acid 촉매에서 황산을 사용하였을 때 보다 높은 분해속도상수를 나타냈다.

• 한국산업보건학회지
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• 제23권4호
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• pp.384-392
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• 2013

Objective: This study inspected incident cases, legal control levels, and GHS(Globally Harmonized System of Classification and Labeling of Chemicals) classification results of strong acids such as hydrogen fluoride, hydrogen chloride, nitric acid, and sulfuric acid, which have been responsible for many recent chemical accidents. As a result, it is deemed necessary for legal control levels of these strong acids to be revised and GHS classification be managed nation-wide. Methods: This study inspected incident cases and legal control levels for strong acids such as hydrogen fluoride, hydrogen chloride, nitric acid, and sulfuric acid. The study analyzed and compared chemical information status and GHS classification results. Results: There were 76 domestic incidents involving strongly acidic hazardous materials over the five years between 2007 and 2011. They include 37 leakage incidents(46.7%) within a workplace, 30 leakage incidents(39.5%) during transportation, and nine leakage incidents(13.8%) following an explosion. The strongly acidic materials in question are defined and controlled as toxic chemicals according to the classes of Substances Requiring Preparation for Accidents, Managed Hazardous Substance, Hazardous Chemical(corrosive) as set forth under the Enforcement Decree of the Toxic Chemicals Control Act and Rules on Occupational Safety and Health Standards of Occupational Safety and Health Act. Among them, nitric acid is solely controlled as a class 6 hazardous material, oxidizing liquid, under the Hazardous Chemicals Control Act. The classification results of the EU ECHA(European Chemicals Agency) CLP(Commission Regulation(EC) No. 790/2009 of 10 August 2009, for the purposes of its adaptation to technical and scientific progress, Regulation(EC) No 1272/2008 of the European Parliament and of the Council on classification, labeling and packaging of substances and mixtures) and NIER (National Institute of Environmental Research) are almost identical for the three chemicals, with the exception of sulfuric acid. Much of the classification information of NITE (National Institute of Technology and Evaluation) and KOSHA(Korea Occupational Safety and Health Agency, KOSHA) is the same. NIER provides 12(41.4%) out of 29 classifications, as does KOSHA.

• 한국대기환경학회지
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• 제13권1호
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• pp.9-18
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• 1997

Precipitation samples were collected by the wet- only event sampling method from Seoul during September 1991 to April 1995. These samples were analyzed for the concentrations of the major ionic components (N $O_3$$^{[-10]}$ , N $O_2$$^{[-10]}$ , S $O_4$$^{2-}$, C $l^{[-10]}$ , $F^{[-10]}$ , N $a^{＋}$, $K^{+}$, $Ca^{2＋}$, $Mg^{2＋}$, and N $H_4$$^{＋}$), pH, and electric conductivity. During the study period, a total of 182 samples were collected, but only 163 samples were used for the data analysis via quality assurance of precipitation chemistry data. The volume-weighted pH was found to be 4.7. The major acidifying species from our precipitation studies were identified to be non-seasalt sulfate (84$\pm$9 $\mu$eq/L) and nitrate (24$\pm$2 $\mu$eq/L) except for chloride. Because the Cl/Na ratio in the precipitation was close to the ratio in seawater. If all of the non-seasalt sulfate and nitrate were in the form of sulfuric and nitric acids, the mean pH in the precipitation could have been as low as 3.7 lower than the computed value. Consequently, the difference between two pH values indicate that the acidity of precipitation was neutralized by alkaline species. The equivalent concentration ratio of sulfate to nitrate was 3.5, indicating that sulfuric and nitric acids can comprise 78％ and 22％ of the precipitation acidity, respectively. Analysis of temporal trend in the measured acidity and ionic components were also performed using the linear regression method. The precipitation acidity generally showed a significantly decreasing trend, which was compatible with the pattern of the ratio (N $H_4$$^{＋}$＋C $a^{2＋}$)/ (nss-S $O_4$$^{2-}$＋N $O_3$$^{[-10]}$ ).).