• 한국환경농학회지
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• 제10권1호
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• pp.11-19
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• 1991

국내산(國內産) 천연(天然) Zeolite를 이용(利用)하여 저렴(低廉)한 중금속흡착제(重金屬吸着劑)의 개발(開發)을 위해 이온 교환용량(交換容量)이 큰 Zeolite를 합성(合成)하고 이것의 중금속(重金屬) 흡착능력(吸着能力)을 조사(調査)하였다. 천연(天然) Zeolite의 주(主) 구성(構成) 점토광물(粘土鑛物)은 Clinoptilolite와 Mordenite였으나 합성(合成) Zeolite는 Phillipsite였다. 시료(試料)에 의(依)한 Cu와 Zn의 흡착반응(吸着反應)은 1시간(時間) 이후(以後)에 흡착평형(吸着平衡)에 도달(到達)하였다. 흡착량(吸着量)은 시료량(試料量) 및 첨가중금속(添加重金屬) 이온들의 농도(濃度)가 증가(增加)할수록 증가(增加)하는 경향(傾向)이었으며 합성(合成) Zeolite가 천연(天然) Zeolite에 비(比)해 고농도(高濃度)에서 흡착율(吸着率)이 높았다. 중김속(重金屬) 흡착량(吸着量)은 pH가 증가(增加)할수록 증가(增加)하는 경향(傾向)이었으나 합성(合成) Zeolite가 천연(天然) Zeolite에 비(比)해 pH 생존성(生存性)이 낮았다. 중금속(重金屬) 흡착량(吸着量)은 천연(天然) Zeolite에 비(比)하여 합성(合成) Zeolite가 훨씬 높았다. 염용액(鹽溶液)의 농도(濃度)가 높을수록 많은 양(量)의 중금속(重金屬) 이온이 합성(合成) Zeolite에서 탈착(脫着)되었으며 그 정도(程度)는 NaCl<$CaCl_2$<$AlCl_3$의 순(順)이었다. 따라서 합성(合成) Zeolite보다 중금속(重金屬) 제거효과(除去效果)가 우수(優秀)한 것으로 판단(判斷)된다.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.563-567
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• 2006

The application of a synergistic solvent extraction by the formation of ternary complex with pyrocatechol violet (PV) and benzalkonium chloride (BC) was studied for determination of trace Zn(II) in water samples. The pH of sample solution and the amount of PV and BC added were optimized for the formation of the stable complex, a proper solvent was selected for the effective extraction, and the concentration of nitric acid was fixed for the back extraction of the complex from the solvent. After the ionic strength of 100 mL sample solution was adjusted to 0.1 M by adding NaCl and the pH was fixed at 9 with a carbonate buffer, 1.0 mL of 2% PV solution was added to form Zn(II)-PV complex then the Zn(II)-PV/BC ternary complex was made by adding 1.0 mL of 10% BC solution. The ternary complex was extracted into 10 mL of MIBK. And the ternary complex was back-extracted with 10 mL of 1.0 mol/L nitric acid to determine Zn(II) by a flame atomic absorption spectrophotometer (flame-AAS). The interference of concomitant ions on the extraction of Zn(II) was investigated. This procedure was applied to the analysis of three real samples such as Dalbang-dam water, laboratory tap water and Jungnajin seawater. The recoveries of Zn(II) in spiked samples were 86.58-104.1%.

• 한국식품과학회지
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• 제28권4호
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• pp.663-667
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• 1996

파로부터 acid phosphatase를 Sephacryl S-200 gel filtration과 CM-Sepharose CL-6B ion exchange chromatography를 이용하여 부분정제하였다. p-nitrophenyl phosphate를 기질로 사용했을 경우에 최적pH는 5.5, 최적온도는 $60^{\circ}C$였다. 효소의 활성화 에너지는 4.86kcal/mole이었다. 효소는 pH 6.0에서 가장 안정하였으며, $50^{\circ}C$ 이하에서 대체로 안정하였다. 효소는 p-nitrophenyl phosphate를 기질로 가장 잘 이용하였으며, 5'-IMP와 5'-GMP는 기질로 거의 이용하지 못하였다. 효소는 p-nitrophenyl phosphate를 기질로 했을 경우에 $K_{m.app.}$값이 0.87mM이었다 $Cr^{+++},\;Zn^{++},\;Cu^{++}$이온은 효소의 활성을 저해하였으며, 또한 molybdate와 metavanadate 이온이 효소의 활성을 저해하였다. 그리고, NaCl의 농도가 높을수록 효소의 활성을 저해하였다.

• 한국식품저장유통학회지
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• 제19권6호
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• pp.849-857
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• 2012

전처리 방법에 따른 적외선건조 복숭아의 이화학적 및 기능적 특성을 조사한 결과 수분함량은 0.3% NaCl 용액 침지구에서 낮게 나타났다. 가용성 고형분 함량은 vitamin C와 soluble Ca 처리 농도가 증가함에 따라 유의적으로 증가하는 경향을 보였다. 식미와 밀접한 관계가 있는 당산비는 0.1% vitamin C처리구와 2.0% soluble Ca처리구에서 높은 값을 나타내었다. 색도는 각각의 전처리구에 있어서 $L^*$ 값 및 $a^*$ 값은 높고 $b^*$ 값은 낮은 경향을 나타내어 갈변이 억제되는 결과를 보였다. 절단력은 전처리구가 무처리구에 비하여 높게 나타났으며, soluble Ca 처리에 따른 무기질 함량은 K > Mg > Ca > Na > Fe > Zn > Cu의 순을 나타내었으며 soluble Ca의 처리 농도가 증가됨에 따라 무기질 함량과 Ca의 함량 또한 증가하는 것으로 나타났다. 관능특성에서는 각각의 전처리 구가 무처리구에 비하여 전반적으로 기호도가 높아지는 결과를 나타내었다. 전처리방법에 따른 적외선건조 복숭아의 총 폴리페놀 및 플라보노이드 함량은 전반적으로 무처리구에 비해 0.1% vitamin C처리구, 1.0% soluble Ca 처리구에서 높게 나타났으며 ABTS 라디칼 소거 활성에서도 이와 유사한 경향을 나타내었다. 이상의 결과에서 이화학적, 기능적 품질특성을 고려해 보았을 때 0.1% vitamin C 전처리와 적외선건조방법을 효과적으로 이용하는 것이 고품질 복숭아 건조제품을 제조할 수 있는 방안이 될 것으로 사료된다.

• 자원환경지질
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• 제30권3호
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• pp.197-207
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• 1997

Rocks in the Cheongsong mine area consist of Precambrian gneiss, Cretaceous sedimentry rocks and late Cretaceous quartz porphyry. The Cheongsong deposit is composed of many hydrothermal quartz veins of strikes $N30^{\circ}{\sim}60^{\circ}W$, dips $60{\sim}85^{\circ}E$ which fill WNW fault system. Pyrite and hematite occur within transparent quartz near margins of early stage II, and milky quartz of middle stage II coexists with sphalerite, chalcopyrite and galena coexisting with Cu-Pb-Bi minerals in center part of stage II quartz veins. Stage III calcite vein filled cracks or fractures of earlier quartz veins contains native copper and chalcopyrite. Supergene minerals are chalcocite, covellite, malanchite and chrysocolla. Alteration minerals are sericite, chlorite, argillite, epitode and pyrite. Ranges of salinities and homogenization temperatures for fluid inclusions in the individual periods of stage II are: 3.7 to 7.8 wt.% eq. NaCl and 200 to $380^{\circ}C$ in transparent quartz of early stage II; 0.7 to 6.4 wt.% eq. NaCl and 200 to $320^{\circ}C$ in milky quartz of middle stage II; 0.0 to 0.9 wt.% eq. NaCl and 250 to $320^{\circ}C$ in calcite of late stage II. Those of stage III calcite range about 0 wt.% eq. NaCl, and from 140 to $260^{\circ}C$, respectively. The relationship between salinities and temperatures shows decrease tendency with paragenetic time from stage II to III. The ${\delta}^{18}O_{H_2O}$ value is 0.5‰ in stage I, range from 0.5 to -0.4‰ in stage II, and from -3.2 to -3.7‰ in stage III. Calcite in the stage II and stage III has ${\delta}^{13}C$ values of -5.0‰ and -4.5 to -4.9‰, respectively. There is a decrease in sulfur fugacity values with paragenetic time of stage II, from $10^{-6.3}$ atm for early mineralization, to $10^{-6.5}$ atm for middle stage, to $10^{-8.0}$ atm for late mineralization of stage II. The results of stable isotope and fluid inclusion indicate that ore fluids reacted with meteoric water and wall rock in the Cheongsong hydrothermal system.

• 한국주조공학회지
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• 제36권2호
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• pp.60-66
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• 2016

In this study, comparison of corrosion properties of the Mg-1.5Ge-1Zn (GZ21) alloy and Mg-9Al-1Zn (AZ91) alloy were investigated. The studied alloys were fabricated by permanent mold casting method. And the potentiodynamic test, hydrogen evolution test, immersion test and A.C Impedance test were carried out in a 3.5% NaCl solution with pH7.2 at room temperature to measure the corrosion properties. The microstructure of GZ21 alloy was composed of ${\alpha}-Mg$ and $Mg_2Ge$ phases and AZ91 alloy was composed of ${\alpha}-Mg$ and $Mg_{17}Al_{12}$ phases. From the test results, the corrosion property was improved by adding Ge. It seemed that the corrosion mechanism was changed from galvanic corrosion (AZ91) to filiform corrosion (GZ21).

• Journal of Applied Biological Chemistry
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• 제60권3호
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• pp.257-263
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• 2017

A cellulolytic strain Y2 was isolated from soil obtained in the Canadian Alpine region. The isolate was identified as Paenibacillus sp. Y2 by 16S rRNA sequencing. When grown in LB medium supplemented with carboxymethyl-cellulose (CMC), CMCase production increased to 122.0% of that observed in LB without CMC. Culture supernatant was concentrated by ultrafiltration and 80% ammonium sulfate precipitates were separated by Hi-Trap Q and CHT-II chromatography. The purified enzyme (EG-PY2) showed a homogeneous single band and the molecular mass was estimated to be 38 kDa by SDS-PAGE. Optimum pH and temperature of the enzyme were 4.5 and $30^{\circ}C$, respectively. The half-life of enzyme activity at 50 was 140.7 min, but the enzyme was drastically inactivated within 5 min at $55^{\circ}C$. The enzyme was highly activated to 135.7 and 126.7% by 5.0 mM of $Cu^{2+}$ or $Mg^{2+}$ ions, respectively, and moderately activated by $Ba^{2+}$ and $Ca^{2+}$ ions, whereas it was inhibited to 76.8% by $Fe^{2+}$, and to ${\leq}50%$ by $Mn^{2+}$, $Co^{2+}$, $Zn^{2+}$, and EDTA. The enzyme was activated to 211.5% in the presence of 0.5 M of NaCl and greatly tolerant to 3.15M of NaCl. The enzyme showed 2.98 times higher ${\beta}$-glucanase activity than CMCase activity. Based on these results, it can be concluded that EG-PY2 is an acidophilic, cold-active, and halotolerant endoglucanase. The authors suggest it is considered to be useful for various industrial applications, such as, fruit juice clarification, acidic deinking processes, high-salt food processing, textile and pulp industries, and for biofuel production from seaweeds.

• 한국물환경학회지
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• 제21권1호
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• pp.46-51
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• 2005

The photocatalytic oxidation of Rhodamine B (RhB) was studied using immobilized $TiO_2$ and rotating disk photocatalytic reactor. Immobilized $TiO_2$ onto the surface of the aluminum plate was employed as the photocatalyst and two 20 W germicidal lamps and two 20 W UV-BLB lamps were used as the light source and the reactor volume was 1.0 L. The effects of parameters such as the number of rotating disk, rpm of rotating disk, the number of coating, $H_2O_2$ and photo-fenton amounts, and the concentrations of anions and cations ($NO_3{^-}$, $SO_4{^{2-}}$, $Cl^-$, $Ca^{2+}$, $Zn^{2+}$, $Na^+$) were examined.

• KSBB Journal
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• 제13권3호
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• pp.320-324
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• 1998

Agar degrading enzyme-agarase-was purified from the culture fluid of Cytophaga so/ ACLJ-18, by acetone precipitation, DEAE-Cellulose, Sephadex G-100 and CM-Sephadex C25 column chromatographies. The molecular weight of purified agarase was estimated to be 24,700 dalton by SDS-polyacrylamide gel electrophoresis. The optimum pH and temperature for agarase activity were 7.0 and 40$^{\circ}C$, respectively. this agarase was stable in the pH range of 6.5 - 8.0 and 40$^{\circ}C$, and required 0.35M NaCl for optimum activity. And this agarase was inhibited by metal ions such as Ba2+, Cu2+, Co2+, Mn2+, Hg2+, Zn2+, and showed specificity on agar.

• 자원환경지질
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• 제22권3호
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• pp.253-266
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• 1989

경북 의성 퇴적분지내에는 수개조의 함 Cu-Pb-Zn-Ag 열수석영맥이 주향 N $20^{\circ}-40^{\circ}W$, 경사 $70^{\circ}-80^{\circ}NE$의 단층면을 따라 충진되어 있으며, 맥폭은 1.0m 이하이고, 약 200m 이상 연장되어 있다. 광화작용은 구조운동에 수반되어 3회 (I, II, III기)에 걸쳐 진행되었다. 주 광화시기인 제 I 광화시기에는 주로 황동석, 유비철석, 황철석, 방연석, 섬아연석과 미량의 사면동석 및 함Pb, Ag, Sb, Bi 유염 광물 등이 산출된다. 유체 포유물 연구에 의하면, 제I광화작용시 동(銅)을 위시한 광석 광물은 7.5-4.5wt.% 염상당농도를 갖는 광화유체로부터 초기 $400^{\circ}C$에서 후기 $200^{\circ}C$에 걸쳐 침전되었고, $350^{\circ}C$ 부근에서 광화유체의 비등 현상이 있었음을 확인하였다. $H_2O-NaCl$ 임계곡선에 의해 구한 광화유체의 최대 압력은 150bar이고, 이는 1.7km의 심도에 해당된다. Cu의 침전은 전 유황종(種)의 농도가 $10^{-0.5}-10^{-1.8}M$인 광화유체가 약 $350^{\circ}C$에서 $250^{\circ}C$로 감소되면서 비등작용과 함께 천수유입에 의한 냉각 작용에 의하여, 광화유체 내의 유황, 산소의 분압이 각각 $10^{-8}$, $10^{-30}atm$.에서 $10^{-12}$, $10^{-36}atm$.으로 감소되고, 한편 pH가 증가되어, Cu complex 이온의 농도가 $10^3$에서 10ppm으로 감소되면서 주로 황동석으로 침전되었다. 함 Pb, Ag, Sb, Bi 유염광물은 $250^{\circ}C$ 이하에서 유황과 산소분압이 각각 $10^{-12}$, $10^{-36}atm$. 이하인 광화유체에서 계속되는 천수유입으로 인한 냉각작용과 희석작용에 의해 침전되었다.