• Journal of Korean Society for Atmospheric Environment
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• 제22권E1호
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• pp.27-34
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• 2006

Although the importance of size-resolved raindrops study has been known, it has not been popularized up to the present. In the present study, an attempt was made to generalize the size-resolved raindrops study by a combination of the frozen raindrop collection method and a commercially available high-performance capillary electrophoresis (HPCE). Samplings were carried out at Kyoto, Japan in October 2002. The inorganic ions (chloride, nitrate, sulphate, calcium, ammonium, sodium, magnesium, potassium) in size classified raindrop samples were successfully analyzed by HPCE with good repeatability. To assure the accuracy and precision of HPCE data, t-test was conducted with paired analytical data, which were experimentally constructed by analyzing standard solutions with HPCE and IC, respectively. T-test showed that there is no notable difference between the concentrations determined by the two analytical methods. Every ionic concentration in both cation and anion was found to be strong raindrop size dependence. Though there was slight increase of sodium and sulphate concentrations between 0.85 mm and 1.15 mm raindrop radius, it showed a strong decrease for every ionic component with increasing droplet radius. The combination of the frozen raindrop collection method and a commercially available HPCE can meet the need of size-resolved raindrops study.

• 한국미생물·생명공학회지
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• 제18권1호
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• pp.35-38
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• 1990

정제된 저해물질의 Rf치는 0.12-0.71 사이였으며 melting point는 154.3-155.3$^{\circ}C$로 나타났다. 물, formic acid, ethylene glycol monomethyl ether에는 용해되지만 그외 대부분의 용매에서는 불용성이었고 흡습성이 매우 큰 물질이었다. Phenol-sulfuric acid, ninhydrin, silvernitrate-sodium hydroxide 반응은 양성이었으나, DNS 반응에서는 음성이며 자외선 조사하에서 형광을 나타내었다. 저해물질의 구성성분은 fructose와 aspartic acid로 확인되었으며 분자량이 약 1,050 정도였다.

• 센서학회지
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• 제32권2호
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• pp.67-74
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• 2023

A microfluidic paper-based analytical device (µPAD) is proposed for the selective detection of ammonia in water by using the modified Berthelot reagent and a fluidic channel consisting of hollow paper. The modified Berthelot reagents were uniformly dispersed in cyclohexane and then immobilized in a detection zone of the µPAD. The loading position of the reagents and the type of a sample flow channel were optimized to achieve a sensitive ammonia detection within a short analytical time. The NH₃ µPAD exhibits a linear colorimetric response to the concentration of ammonia dissolved in water in the range of 1-100 mg L^-1, and its limit-of-detection is 1.75 mg L^-1. In addition, the colorimetric response was not influenced by the addition of 100 mg L^-1 nitrogen containing compounds (sodium nitrate, sodium nitrite, uric acid, hydroxylamine, butylamine, diethylamine) or inorganic salts (NaCl, Na₂HPO₄), presenting the enough selectivity in the detection of water-dissolved ammonia against possible interferents.

• 분석과학
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• 제12권1호
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• pp.34-39
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• 1999

에스트로겐의 일종인 에스트론은 수은 전극에서 전기 화학적 행동을 보이지 않기 때문에 폴라로그래피로 직접 정량하기는 어렵다. 에스트로겐의 nitro 유도체들은 전기화학적 활성을 갖기 때문에 본 물질을 nitration시켜 전압-전류법으로 정량하였다. Nitration 반응은 sodium nitrite를 사용하여, $100^{\circ}C$ 항온조에서 30분동안 가열하였다. 순환 전압-전류법으로 에스트론의 전기 화학적 행동을 조사하였고, 시차 펄스 음극 벗김 전압-전류법으로는 미량의 에스트론을 정량하는 방법을 연구하였다. 그 결과 borate buffer 용액내에서 nitrated estrone의 환원 전위는 -0.61 V에서 선명한 봉우리를 나타내었다. Nitrated estrone은 수은 전극에서 비가역과정이고, 수은 방울에 강하게 흡착되었다. 에스트론을 정량하기 위한 최적조건은 0.05 M sodium nitrite, 0.01 M sodium borate, 흡착 수집 전위는 -0.1 V(vs. Ag/AgCl) 및 pH 11.0 이었다. 흡착 수집 시간은 2분 그리고 주사 속도는 10 mV/sec일 때 에스트론의 검출한계는 $1{\times}10^{-9}M$이었다.

• 한국식품과학회지
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• 제5권2호
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• pp.89-94
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• 1973

육제품(肉製品)의 착색제(着色劑)로 사용되고 있는 식용적색2호(食用赤色2號)와 황색4호(黃色4號)의 가열(加熱) 및 감마(線) 조사(照射)에 의한 변색정도(變色程度)와 첨가물(添加物)에 의한 영향을 model system 을 사용하여 관찰하였다. 황색2호(黃色2號)는 가열(加熱)에 의하여 뚜렷한 변색(變色)을 나타내지 않았으나 황색4호(黃色4號)는 Na-TPP 와 cinnamon oil 을 첨가(添加)하므로써 약간의 퇴색(褪色)을 하였다. 감마선(線) 조사(照射)에 의한 영향은 선량(線量)의 증가와 더불어 퇴색(褪色)하였으며 $NaNO_2$ 와 ascorbic acid 는 퇴색(褪色)을 억제하는 반면 Na-TPP 와 cinnamon oil 은 오히려 촉진하는 경향을 보였다. 이러한 퇴색도(褪色度)는 적색2호(赤色2號)보다는 황색4호(黃色4호(號)가 더욱 현저하였으며 $5^{\circ}C$ 보존(保存)보다는 $25^{\circ}C$보존(保存)에서 퇴색(褪色)이 촉진되었다.

• 한국환경농학회지
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• 제24권2호
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• pp.98-105
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• 2005

Groundwater sampled from 24 tube wells of three districts namely Sherpur, Gaibandha and Naogaon in Bangladesh was appraised for their water quality for irrigation and agro-based industrial usage. All waters under test were slightly alkaline to alkaline (pH = 7.2 to 8.4) in nature and were not problematic for crop production. As total dissolved solid (TDS), all groundwater samples were classified as fresh water (TDS<1,000 mg/L) in quality. Electrical conductivity (EC) and sodium adsorption ratio (SAR) values reflected that waters under test were under medium salinity (C2), high salinity (C3) and also low alkalinity (S1) hazard classes expressed as C2S1 and C3S1. As regards to EC and soluble sodium percentage (SSP), groundwater samples were graded as good and permissible in category based on soil properties and crop growth. All water samples were free from residual sodium carbonate (RSC) and belonged to suitable in category. Water samples were under soft moderately hard, hard and very hard classes. Manganese, bicarbonate and nitrate ions were considered as major pollutants in some water samples and might pose threat in soil ecosystem for long-term irrigation. For most of the agro-based industrial usage, Fe and Cl were considered as troublesome ions. On the basis of TDS and hardness, groundwater samples were not suitable for specific industry. Some water samples were found suitable for specific industry but none of these waters were suitable for all industries. The relationship between water quality parameters and major ions was established. The correlation between major ionic constituents like Ca, Mg, K, Na, $HCO_3$ and Cl differed significantly. Dominant synergistic relationships were observed between EC-TDS, SAR-SSP, EC-Hardness, TDS-Hardness and RSC-Hardness.

• Advances in materials Research
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• 제9권3호
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• pp.219-231
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• 2020

The aim of this study is to investigate the durability of fly ash based geopolymer mortar with and without protective coatings in aggressive chemical environments. The source materials for geopolymer are Fly ash and Ground Granulated Blast furnace Slag (GGBS) and they are considered in the combination of 80% & 20% respectively. Two Molarities of NaOH solution were considered such as 8M and 10M. The ratio of binder to sand and Sodium silicate to Sodium hydroxide solution (Na₂SiO₃/NaOH) are taken as 1:2 and 2 respectively. The alkaline liquid to binder ratio is 0.4. Compressive strength tests were conducted at various ages of the mortar specimens. In order to evaluate the performance of coatings on geopolymer mortar under aggressive chemical environment, the mortar specimens were coated with two different types of coatings such as epoxy and Acrylic. They were then subjected to different chemical environments by immersing them in 10% standard solutions of each ammonium nitrate, sodium chloride and sulphuric acid. Drop in compressive strength as a result of chemical exposure was considered as a measure of chemical attack and the drop in compressive strength was measured after 30 and 60 days of chemical exposure. The compressive strength results following chemical exposure indicated that the specimens containing the acrylic coating proved to be more resistant to chemical attacks. The control specimen without coating showed a much greater degree of deterioration. Therefore, the application of acrylic coating was invariably much more effective in improving the compressive strength as well as the resistance of mortar against chemical attacks. The results also indicated that among all the aggressive attacks, the sulphate environment has the most adverse effect in terms of lowering the strength.

• 한국축산식품학회지
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• 제41권5호
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• pp.840-854
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• 2021

The impact of green tea extract powder and rosemary extract powder, alone or in combination, on the quality characteristics of naturally cured pork sausages produced with white kimchi powder as a nitrate source was evaluated. Ground pork sausages were assigned to one of seven treatments: control (0.01% sodium nitrite and 0.05% sodium ascorbate), treatment 1 (0.3% white kimchi powder and 0.05% green tea extract powder), treatment 2 (0.3% white kimchi powder and 0.1% green tea extract powder), treatment 3 (0.3% white kimchi powder and 0.05% rosemary extract powder), treatment 4 (0.3% white kimchi powder and 0.1% rosemary extract powder), treatment 5 (0.3% white kimchi powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder), and treatment 6 (0.3% celery juice powder, 0.05% green tea extract powder, and 0.05% rosemary extract powder). Naturally cured products had lower (p<0.05) cooking yield and residual nitrite content than control sausages. However, compared to the control, naturally cured products with white kimchi powder (treatments 1 to 5) showed similar the pH, oxidation-reduction potential, CIE L^* values, CIE a^* values, nitrosyl hemochrome content, total pigment content, and curing efficiency to the control. When the amount of green tea extract powder or rosemary extract powder was increased to 0.1% (treatments 2 and 4), lipid oxidation was reduced (p<0.05). These results indicate that green tea extract powder, rosemary extract powder, and white kimchi powder may provide an effective solution to replace synthetic nitrite and ascorbate used in traditionally cured products.

• 한국미생물·생명공학회지
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• 제10권1호
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• pp.15-26
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• 1982

서류 및 각종 퇴비를 분리원으로 하여 전분 이용성이 좋은 균주는 분리하였고 이 균주를 이용하여 균체 및 지방질을 가장 많이 얻기 위한 최적 배양조건을 구명한 결과는 다음과 같다. 1. 선발된 우수 균주는 Mucor plumbeus로 동정되었다. 2. 이 균주는 전분을 탄소원으로 이용하여 그 함량이 21%일 경우 배양 20일 째에 균체량은 배지 50$m\ell$당 2.09$\pm$0.24g이고 지방질량은 건조 균체 당 37.43%이었다. 3. 질소원으로서는 질산나트륨, 질산칼륨, 질산마그네슘, 요소, 및 초산암모늄 중 요소를 이용하는 경우 균체 및 지방질 생산량이 가장 높았고 그 최적 농도는 2.14g/$\ell$으로 배양25일에서 균체량은 배지 50$m\ell$당 2.39$\pm$0.07g 지방질 함량은 건조균체당 50.73%이었다. 4. 무기질원으로 황산아연. 황산마그네슘, 인산이수소나트륨. 황산칼륨 및 염화제 2 철은 모두Mucor plumbeus FRI 0007 생장에 필요하나 필수적으로 요구되지는 않으며 황산칼륨을 0.44g/$\ell$ 혹은 황산마그네슘을 5.00g/$\ell$ 만을 첨가하는 경우에 소비 전분량에 대한 지방질 생산률은 14.96 및 15.37, 균체 생산률은 31.12 및 26.10으로 다른 처리구 보다 높았다.

• 환경생물
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• 제23권4호
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• pp.374-378
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• 2005

A diffusion - precipitation method was developed to determine acid volatile sulfide (AVS) concentrations in freshwater sediments. This method uses silver nitrate as a sulfide trap solution and the concentration of trapped sulfide is determined gravimetrically. The proposed diffusion - precipitation method is more rapid and less expensive than previously developed purge- and - trap methods. Spiked sodium sulfide recoveries using this method $(97\~120\%)$ were similar with a previously developed diffusion - absorption method $(93.8\~115\%)$ and about $20\%$ greater than a previously developed purge-and-trap method $(74.6\~105\%)$. Detection limit of this method $(0.1\;{\mu}mole\;S\;g^{-l})$ was comparable with that of diffusion-absorption method $(0.06\;{\mu}mole\;S\;g^{-l})$ and purge-and-trap method $(0.05\~0.5\;{\mu}mole\;S\;g^{-l})$.