• 한국염색가공학회지
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• 제22권2호
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• pp.123-131
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• 2010

Shape and size controlled synthesis of gold particles has been studied by using wet-chemical method. When ${AuCl_4}^-$ in aqueous $HAuCl_4$ precursor was reduced using $Na_2SO_3$ as a reducing agent, mixtures of spherical, triangular and hexagonal particles were prepared in a few minutes. It was found that the shape selective oxidative etching by ${AuCl_4}^-\;+\;Cl^-$ anions and crystal growth took place simultaneously. As the ${AuCl_4}^-$ and $Cl^-$ concentration increased, yields of large triangular and hexagonal plate type particles increased, while the spherical particles decreased in most cases. Possible etching and growth mechanisms are discussed.

• EDISON SW 활용 경진대회 논문집
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• 제3회(2014년)
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• pp.39-51
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• 2014

산성비의 주요 원인인 이산화황($SO_2$)을 배기가스로부터 효과적으로 제거하기 위한 용매 중 이온성 액체(ionic liquid, IL)의 $SO_2$ 흡수능 (absorption capacity)을 양자화학적 방법을 이용하여 평가했다. 이를 위해 hydroxyl ammonium 계열의 양이온 monoethanolammonium, diethanolammonium 2종과 carboxylate 계열의 음이온 acetate, formate 2종을 조합하여 총 4종의 IL을 연구에 적용했다. $SO_2$가 IL의 pair, 양이온 또는 음이온과 complex를 형성할 때로 구분하여 계산 모델을 세웠으며, 열역학적 상태 변화와 오비탈 상호작용 분석을 통해 흡수능을 평가하였다. 계산 결과, 음이온-$SO_2$ complex를 적용했을 때 formate에 비해 acetate가 $SO_2$ 흡수에 유리할 것으로 분석되었으며, 이는 이전의 실험 연구에서 얻어진 흡수능 경향성과도 잘 맞는다.

• 한국세라믹학회지
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• 제48권6호
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• pp.584-588
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• 2011

In this work, effects of limestone powder on hydration of $C_3A-CaSO_4{\cdot}2H_2O$ system was discussed based on the XRD Quantitative analysis, and the possibility of Delayed Ettringite Formation was also discussed. The early hydration of $C_3A$ was delayed by addition of $CaCO_3$ powder. The delay effect was enhanced by increasing of $CaCO_3$ content and finer powder of $CaCO_3$ addition. After consumption of $CaSO_4{\cdot}2H_2O$, the reaction of $CaCO_3$ is started. Delayed Ettringite Formation would take place because monosulfoaluminate is not stable in presence of $CaCO_3$. In order to prevent the delayed ettringite formation in $C_3A-CaSO_4{\cdot}2H_2O-CaCO_3$ system, the reduction of monosulfoaluminate formation is important. Therefore, by increasing the amount of $CaCO_3$ addition and finer $CaCO_3$ powder addition, the delayed ettringite formation can be prevented.

• 동아시아식생활학회지
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• 제20권5호
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• pp.769-775
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• 2010

Quality characteristics and antioxidant activity of spirulina with added tofu were investigated in the presence of different coagulants ($CaSO_4$, $MgCl_2$, Glucono delta lactone (GDL), vinegar). The yield of the spirulina tofu was the highest when coagulated with GDL. The pH of spirulina tofu with $MgCl_2$ was the highest compared to those of other coagulants. The tumidity of spirulina tofu was the highest with $MgCl_2$. In the color analysis of spirulina tofu, the L (lightness) value was the highest with $CaSO_4$, whereas a (redness) value was the highest with $MgCl_2$. C-phycocyanin contents were the highest with the $CaSO_4$. Phycoerythrin of spirulina tofu for vinegar was 0.194 mg/mL, and GDL content was 0.214 mg/mL. Additionally, the antioxidant activity of spirulina tofu was the highest with $MgCl_2$ $IC_{50}$ values of the DPPH radical scavenging activity of spirulina tofu with $MgCl_2$ was 89.2 mg/g, GDL 93.5 mg/mL, $CaSO_4$ 116.7 mg/mL, and vinegar 118.0 mg/mL. The texture analyses (TPA) results showed that hardness was in the order of vinegar>$MgCl_2$>GDL>$CaSO_4$. For the overall acceptability of the preference test, the spirulina tofu that was made using $MgCl_2$ coagulant had the highest score. Based on these results, it is suggested that $MgCl_2$ is the proper coagulant for the preparation of spirulina with added tofu.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1859-1864
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• 2011

Two lanthanide complexes, $[Ln(NO_3)_2(H_2O)_3(L)_2](NO_3)(H_2O)$ {Ln = Eu (1), Tb (2); L = 2-(4-pyridylium)-ethanesulfonate, $(4-pyH)^+-CH_2CH_2-SO_3^-)$}, were prepared from lanthanide nitrate and 4-pyridineethanesulfonic acid in $H_2O$ under microwave-heating conditions. Complexes 1 and 2 are isostructural, and the lanthanide metal in both complexes is coordinated to nine oxygen atoms. The pyridyl nitrogen in the ligand is protonated to give a zwitter ion that possesses an $NH^+$ (pyridyl) positive end and an $SO_3^-$ negative end. All O-H and N-H hydrogen atoms participate in hydrogen bonds to generate a two-dimensional (complex 1) or a three-dimensional network (complex 2). Complex 1 exhibits an intense red emission, whereas complex 2 exhibits an intense green emission in the solid state at room temperature.

• 한국구조물진단유지관리공학회 논문집
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• 제21권1호
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• pp.109-116
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• 2017

본 연구는 플라이애시 및 고로슬래그 미분말을 활용하여 알칼리 활성화 결합재로 제조된 모르타르 및 페이스트 샘플의 황산염 저항성을 평가하고 황산염 침투에 대한 고저항성 결합재를 제시하는 것이다. 이를 위하여 플라이애시 및 고로슬래그미분말 등의 광물질 혼화재를 결합재로 활용하여 고로슬래그미분말 치환율을 30, 50 및 100%로 제작하였다. 규산나트륨 모듈 $Ms[SiO_2/Na_2O]$은 1.0, 1.5 및 2.0으로 조정하였으며, 10% 황산나트륨, 10% 황산마그네슘, 10% 질산마그네슘 및 5% 질산마그네슘+5% 황산나트륨 용액에 각각 침지시키고, 황산염 저항성을 평가하기 위하여 압축강도, 질량변화율, 길이변화율 및 X선 회절분석을 측정하였다. 그 결과 10% 황산나트륨, 10% 질산마그네슘 및 5% 질산마그네슘+5% 황산나트륨에 침지한 경우에는 모든 시험조건에서 장기적인 강도발현과 질량 및 길이변화율이 작아 저항성이 우수한 것으로 나타났으나, 10% 황산마그네슘에 침지한 경우에는 장기적인 강도저하와 질량 및 길이변화가 크게 나타났으며, 그 경향은 고로슬래그 미분말 치환량 및 Ms비가 증가할수록 현저하였다. 이것은, X선 회절분석 결과 황산마그네슘 용액 침지에서는 gypsum($CaSO_4{\cdot}2H_2O$) 및 brucite(MgOH)생성되어 내부조직이 팽창하는 것에 의한 것으로 확인되었다. 결론적으로 일정 농도의 ${SO_4}^{2-}$이 존재하는 조건에서 $Mg^{2+}$가 추가로 존재할 경우 열화현상은 가속화되는 것을 알 수 있다.

• 공업화학
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• 제10권5호
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• pp.784-788
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• 1999

본 연구에서는 $Na_2SO_4,\;Na_2CO_3,\;SDS$와 $NaClO_4$ 전해질용액에서 피롤단량체를 전기중합한 후, 중합시간과 전해질에 따른 피롤중합막의 점탄성 특성을 QCA를 이용하여 분석하였다. 그리고, 180초간 피롤을 중합하여 피막한 수정진동자를 0.1 M $NaClO_4$ 전해질용액에 넣어서 전위주사하여 각각의 전해질에 대한 폴리피롤박막의 산화환원특성을 분석하였다. 본 실험에서는 수정진동자의 한쪽 전극을 작용전극으로 사용하였으며, 각각의 실험에서 공진주파수, 공진저항, 전류 값을 측정하여 분석하였다. 본 연구 결과, $ClO_4{^{-}}$와 $DS^-,\;SO_4{^{-2}},\;CO_3{^{-2}}$의 순서로 피롤막이 탄성막에서 점차 점탄성막으로 변하여 가면서 중합됨을 알 수 있었다.

• 한국대기환경학회지
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• 제15권5호
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• pp.555-566
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• 1999

The rainwater samples were collected from the 1100 Site of Mt. Halla and Cheju city during the period of March in 1997 to August in 1998, and the major soluble ions were analyzed. The confidence of analytical data was confirmed by using the comparison methods such as ino-balance, electric conductivity and acid fraction, all of which correlation coefficients were above 0.94. The ionic strengths lower than $10^{-4}$ M, the basis for the pure rainwater, were found in 47% and 38% at 1100 Site and Cheju city, respectively. The precipitations in Cheju city were more influenced by the oceanic effect than those in 1100 Site. The acidity contribution was mainly by $SO_4^{2-}$ and $NO_3^-$ in both areas, and the organic acids have contributed to the acidity with only 5~7%. The neutralization factors by $NH_3$ were about 46% at both 1100 site and Cheju city, whereas those by $CaCO_3$ were 11% and 15% at 1100 site and Cheju city respectively, and the free acidity were both about 35% in average. From the MSA analysis, it was found that the air in Cheju island has been influenced by the pollution from the other areas. The sources of the rainwater components in 1100 Site and Cheju city were also studied with a factor analyzing way, and the most probable factors were found to be anthropotgenic, oceanic, and soil-sourced. The results of multiple regression analysis have shown that $SO_4^{2-}$ was dissolved mostly in the form of $H_2SO_4, CaSO_4 and (NH_4)_2SO_4$, and $NO_3^-$ was in the form of $HNO_3, Ca(NO_3)_2 and NH_4NO_3$.

• 대한방사선기술학회지:방사선기술과학
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• 제21권1호
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• pp.59-64
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• 1998

[ $CaSO_4$ ] thermoluminescent phosphors was made by sintring the $CaSO_4$ after doping the transition elements Tm, Pd, Dy, V, Mo, Zr. The maximum Peaks are found in the measured $CaSO_4$(Tm, Pd, Dy, V, Mo, Zr) TL glow curve at $130^{\circ}C,\;110^{\circ}C,\;140^{\circ}C,\;100^{\circ}C$, and $120^{\circ}C$ when the heating rate is $5^{\circ}C/sec$. The activation energy of the main peak has been estimated by the peak shape method. The estimated activation energies are 1.02eV, 1.32eV, 1.12eV, 0.80eV, and 1.17eV, respectively. The thermoluminescence process in $CaSO_4$(Tm, Pd, Dy, V, Mo, Zr)are found to the 2nd order when the main peak of the glow curve is analyzed by peak shape method. The dose responses of $CaSO_4$(Tm, Pd, Dy, V, Mo, Zr) phosphors are linear within $4{\times}10^{-4}{\sim}1Gy$ of X-rays.

• 한국대기환경학회지
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• 제26권4호
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• pp.420-431
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• 2010

The water-soluble components have been analyzed from the total suspended particulate (TSP) collected at Gosan site of Jeju Island for ten years (1997~2006), and the long-term variations of ionic constituent concentrations have been investigated in order to understand the pollution characteristics of atmospheric aerosols. Their mean concentrations were in the order of nss-${SO_4}^{2-}$ > $Na^+$ > ${NO_3}^-$ > $Cl^$ > ${NH_4}^+$ > nss-$Ca^{2+}$ > $K^+$ > $Mg^{2+}$. The ${NO_3}^-$ concentrations had increased somewhat smoothly compared to those of ${SO_4}^{2-}$ for the past 10 years, possibly indicating the recent energy consumption pattern changes in China. The concentrations of ionic aerosol components showed mostly higher values during the Asian Dust storm periods, and the concentration ratios of nss-$Ca^{2+}$, ${NO_3}^-$, and nss-${SO_4}^{2-}$ between the Asian Dust and Non-Asian Dust periods were 6.9, 2.4, and 1.3, respectively. The anthropogenic nss-${SO_4}^{2-}$, ${NO_3}^-$, ${NH_4}^+$ and the soil originated nss-$Ca^{2+}$ components showed high concentrations as the air parcels were moved from the Asia continent, on the other hand, their concentrations were relatively low as moving from the Northern Pacific into the Gosan area.