• 한국광물학회지
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• 제31권2호
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• pp.67-73
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• 2018

본 연구는 acid bake-water leaching system (AWS)를 이용하여 Au 정광으로부터 경제적이고 친환경적인 유용금속 용출을 위하여 황산염 용매제의 적용성을 파악하는 것이다. AWS 실험은 전기로를 이용하여 다양한 baking 온도($100^{\circ}C{\sim}500^{\circ}C$)와 황산염 용매제($H_2SO_4$, $K_2SO_4$, $(NH_4)_2SO_4$, $MgSO_4$, $CaSO_4$) 조건에서 수행하였다. Baking 온도가 $400^{\circ}C$까지 증가할수록 유용금속의 용출률은 증가하였다. 용출시간에 따른 AWS 실험결과, 최대 용출률 조건은 $(NH_4)_2SO_4$ 용매제이었다. 본 연구를 통하여 $(NH_4)_2SO_4$ 용매제가 AWS를 이용한 유용금속 용출에 있어 효과적인 용매제로 사용가능함을 입증하였다.

• 한국식품과학회지
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• 제19권2호
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• pp.140-145
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• 1987

폴리에틸렌 글라이콜-덱스트란 흔합수용액이 형성하는 수용액 2상계에서 표면 소수성의 크기를 알고 있는 표준 단백질들의 분획계수를 관찰하였다. 또한 폴리에틸렌 글라이콜(PEG)에 palmitate를 부착시킨PEG-P를 첨가함으로써 상층부의 소수성을 증가 시켰을때 단백질들의 분획계수 변화를 조사하였다. PEG/dextran 2상계에서 단백질의 분획계수는 딘백질의 유효 소수성에 관계없이 2상계의 용적비가 동일한 조건에서 PEG와 dextran의 농도가 함께 증가함에 따라 분획계도 증가하였다. 그러나 PEG에 78%친환도를 가지는 PEG-P를 소량 첨가하여 만든 2상계에서는 유효 소수법이 큰 bovine serum albumin과 $\beta-lactoglobulin$의 분획계수가 10배 이상 증가하였고. 유효 소수성이작은 ovalbumin은 큰 변화를 보이지 않았다. 이러한 분획계수의 급격한 중가는 PEG-P의 첨가량이 아주 낮은 2% 수준일 때 나타났으며 그 이상 침가시에는 모든 단백질이 공히 10% 첨가될때까지 완만히 증가하는 경향을 나타내었다.

• 한국식품조리과학회지
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• 제15권3호
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• pp.231-237
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• 1999

닥나무 추출물의 항암효과를 검토하기 위하여 닥나무뿌리 껍질 methanol 추출물로부터 얻은 분획물(hexane, chloroform, ethylacetate, butanol, aqueous 층)들의 0.05∼1.0mg/ml 농도에 대해서 MTT assay를 통한 세포독성 측정 및 암세포 증식억제 효과를 in vitro로 검색하였고, in vivo에서 BALB/c mouse를 이용한 고형암 성장저지 실험 및 비장 장기 중량변화의 항암실험을 행하여 다음과 같은 결과를 얻었다. 세포독성 실험에 의한 MTT assay 결과 모든 분획물들은 농도 의존성으로 효과가 나타났으며 1.0 mg/ml 농도에서 ethylacetate층은 sarcoma 180 cell에 대하여 75.7%의 가장 높은 세포독성 효과를 나타내었고 그 다음 aqueous, hexane, butanol, chloroform 층 순으로 각각 62.7%, 58.7%, 52.6%, 40.1%의 효과를 보였다. 각 분획물들에 의한 sarcoma 180 cell에 증식억제 효과는 배양일(1, 2, 3, 6일)이 증가함에 따라 암세포수는 증가하였으며 처음 1일째에 암세포 증식억제가 가장 많이 되었다. 1.0mg/ml 농도로 시료를 첨가하여 6일간 배양했을 때 ethylacetate 층은 60%의 억제율로 가장 현저 한 활성을 보였고 aqueous(42%), hexane(31%), butanol(30%), chloroform(19%)층 순으로 암세포 증식억제율을 나타내었다. 또한 암세포 증식에 대한 현미경 관찰을 해 본 결과 ethylacetate층은 대조군에 비하여 암세포 증식억제 정도와 형태 변화가 두드러지게 나타났다. BALB/c mouse에서 sarcoma 180 cell에 대한 각 분획물들의 고형암 성장저지효과는 1.0mg/kg으로 시료투여했을 때 ethylacetate 층은 대조군에 비하여 41%의 유의적인 저지율을 나타냈으며(p<0.05), 그 다음은 유의적이지는 않으나 aqueous 층 처리구가 39%,의 저지율을 나타내었다. 비장의 체중에 대한 중량변화는 대조군의 경우 1.08%인데 비해, ethylacetate층 처리군은 2.10%로 증가하였고 나머지 처리군에서는 대조군과 차이를 나타내지 않았다(p<0.05). 한편, mouse의 체중 변화는 대조군과큰 차이가 없었으므로 시료 추출물로 인한 체중 및 장기의 독성 문제는 없을 것으로 사료된다. 이상의 연구 결과로 닥나무 뿌리 껍질 methanol 추출물로부터 얻은 분획물중 ethylacetate와 aqueous 층은 세포독성 효과와 암세포 성장억제 효과 및 고형암 성장 저지 효과가 크게나타났으며, 체중에 대한 면역관련 장기인 비장의 중량증가로부터 면역계 활성과도 관계가 있을 것으로 사료된다. 따라서 닥나무 뿌리 껍질의 효능이 큰 분획물로부터 항암활성 물질을 분리 정제하고 기전확립의 연구가 앞으로 더욱 보충되어야 할 것이며, 암예방을 위한 기능성 식품 및 치료제의 개발에 대한 가능성 확인을 본 연구를 통하여 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제48권2호
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• pp.554-558
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• 2016

The solubility of nickel ferrite in an aqueous solution of boric acid was studied by varying the pH at the temperatures ranging from $25^{\circ}C$ to $320^{\circ}C$. A flow-through autoclave system was specially designed and fabricated to measure the solubility of Fe in hydrothermal solutions under high temperature and pressure. The performance of this flow-through system was directly compared with the conventional static state technique using a batch-type autoclave system. The stability of fluid velocity for the flow-through autoclave system was verified prior to the solubility measurement. The influence of chemical additives, such as boric acid and $H_2$, on the solubility of nickel ferrite was also evaluated.

• 대한지하수환경학회지
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• 제2권1호
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• pp.22-29
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• 1995

유동 세균 입자는 지체계수를 감소시키므로써 지하수에서 소수성 오염물의 이동을 촉진시킨다. 그 크기와 표면의 적당한 물리화학적 조건으로 인하여 세균은 효율적인 오염물의 운반자가 될 수 있다. 이러한 운반자가 있을 때, 그 계는 액상, 입상, 그리고 고상의 3 상으로 해석되어야한다. 오염물은 각 상에 모두, 혹은 그 중의 일부에 존재할 수 도 있다. 본 연구에서는 세균이 있는 경우, 생화학적으로 분해 가능한 유기성 오염물의 다공매질에서의 거동을 물질수지에 기초하여 수학적 모델로 묘사한다. 세균의 액상과 고상사이의 물질 전이 및 오염물의 액상과 입상사이의 물질 전이는 동역학적 관계식으로 나타냈다. 모델 결과를 일반화하기 위하여 무차원화를 수행했고, 그 해를 구하여 세균에 의한 오염물의 가속이송 효과를 알 수 있었다. 모델 결과는 문헌상의 실험결과와 비교되었다. 모델 결과로부터 오염물은 그 계의 Damkohler I 수가 10 이상일 경우 국지 평형 가정을 할 수 있었으며, 세균의 성장율과 주입 농도 등이 오염물의 청소에 아주 중요한 요소임을 알 수 있었다.

• Macromolecular Research
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• 제12권2호
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• pp.246-250
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• 2004

We have classified a number of aqueous ternary systems containing two different polymers into three types by focusing on the deviation of the Huggins constant k'from the additivity line. Systems of type I have negative deviations of k'; the repulsive interaction between the two different polymers dominates. In systems of type II, k' almost follows the additivity relation; the repulsive and attractive interactions between the two different polymers are balancing. Type III systems have positive deviations of k'; the attractive interactions are relatively dominant. This classification of systems is supported by the fact that the positive and negative deviations of k' from the additivity line also correspond to the sign of interaction parameter between polymer 2 and 3, Δb$\_$23/. Furthermore, we have verified the relatively high compatibility between dextran and poly(vinyl alcohol) by determining the binodal concentration of a liquid-liquid phase separation for a water/dextran/poly(vinyl alcohol) system, which is classified as type III. Thus, we found that the compositional dependence of k' closely relates to the compatibility of binary polymer mixtures in aqueous ternary systems.

• 암석학회지
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• 제8권1호
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• pp.46-55
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• 1999

Fluid inclusions in granite and hydrothermal quartz indicate that three fluids have affected the Sannae granite. The earliest fluid is represented by three-phase aqueous fluid inclusions with high salinity (38 to 46 wt.% NaCl equiv.). It was exsolves from a crystallizing melt and trapped at a relatively high-pressure condition. The secong fluid is represented by two-phase aqueous fluid inclusion with low entectic temperatures (< $-40^{\circ}C$). low- to moderate salinity (3 to 24.0 wt.% NaCl equiv.) and high homogenization temperatures$ ($309^{\circ}C$$473^{\circ}C$)($. This fluid was trapped at higher pressures than 300-500 bars and precipitated molybdenite and wolframite in quartz veins. It was probably generted by fluid-host rock interactions since they show a wide range of salinity within a narrow range of homogenization temperatures. The final fluid is represented by an aquenous fluid boiling that separated into high-salinity (34-38 wt.% NaCl equiv.) and low-salinity fluid (0 to 8.7 wt.%) at $303-376^{\circ}C$ and 50-150 bars. These boiling fluids precipitated euhedral quartz in miarolitic cavities. The compositions of the final fluid was rather complex in the $H_2$O-NaCl-KCI-$FeCl_2$ system. The Sannae granite was a locus for repeated fluid events including magmatic fluids during the final stage of crystallization, the convection of hydrothermal fluids causing a fluid ascending, fluid boiling, and the local W-Mo mineralization and formation of miarolitic cavities due to thermal, tectonic and compositional properties of the felsic granite.

• 대한한의학방제학회지
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• 제8권1호
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• pp.343-358
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• 2000

Epimedii Herba is an important traditional herb medicine widely used as a tonic. However, the mechanism of action of this drug on the immune system is not well studied. This study was performed to elucidate the effects of the aqueous extract of Epimedii Herba on the production of antibodies in mice. Antibodies in serum were detected in male ICR mice treated with the aqueous extract of Eplmedii Herba (AEEH) at a dosage of 40, 120, and 360mg/kg orally for 2 weeks. Effects of oral administration of AEEH on antibody forming responses were measured by enzyme linked immunosorbent assay (ELISA) of immunoglobulin (Ig) levels in serum. The results were as follows; 1. Epimedii Herba slightly decreased body weight gain. 2. Epimedii Herba significantly increased the relative spleen weight. 3. Epimedii Herba significantly increased total serum IgG levels. 4. Epimedii Herba significantly enhanced total serum IgG1 levels. 5. Epimedii Herba significantly increased total serum IgG2a levels. 6. Epimedii Herba markedly increased total serum IgM levels. These findings demonstrate that Epimedii Herba significantly enhances the production of antibodies at therapeutic concentrations, and suggest that administration of Epimedii Herba may prevent the host from immunologic diseases.

• Membrane and Water Treatment
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• 제8권3호
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• pp.259-277
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• 2017

Adsorption is a widely used technique for the removal of dyes from wastewaters by variety of adsorbents. In this work, the main focus is on the potential assessment of anion exchange membrane for the removal of different dyes using batch system and investigation of experimental data by applying various kinetic and thermodynamic models. The removal of anionic dyes i.e., Eosin-B, Eriochrome Black-T and Congo Red by anion exchange membrane BII from aqueous solution was carried out and effect of various parameters such as contact time, membrane dosage, temperature and ionic strength on the percentage removal of anionic dyes was studied. The experimental data was assessed by kinetic models namely pseudo-first-order, pseudo-second-order, Elovich liquid film diffusion, Bangham and the modified Freundlich models equation have been used to analyze the experimental data. These results indicate that the adsorption of these anionic dyes on BII follows pseudo-second-order kinetics with maximum values of regression coefficient (0.992-0.998) for all the systems. The adsorption of dyes was more suitable to be controlled by a liquid film diffusion mechanism. The adsorptive removal of dye Eosin-B and Eriochrome Black-T were decreased with temperature and thermodynamic parameters such as free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$) and entropy (${\Delta}S^o$) for adsorption of dyes on membrane BII were calculated at 298 K, 308 K and 318 K. The values of enthalpy and entropy were negative for EB and EBT representing that the adsorption of these dyes on BII is physiosorptive and exothermic in nature. Whereas the positive values of enthalpy and entropy for CR adsorption on BII, indicating that its adsorption is endothermic and spontaneous in nature. It is evident from this study that anion exchange membrane has shown good potential for the removal of dyes from aqueous solution and it can be used as adsorbent for dues removal on commercial levels.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.421-421
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• 2008

Generally, the polymer thick-film resistors for embedded organic or hybrid substrate are patterned by screen printing so that the accuracy of resistor pattern is not good and the tolerance of resistance is too high(${\pm}$20~30%). To reform these demerits, a method using Fodel$^{(R)}$ technology, which is the patterning method using a photosensitive resin to be developable by aqueous alkali-solution as a base polymer for thick-film pastes, was recently incorporated for the patterning of thermosetting thick-film resistor paste. Alkali-solution developable photosensitive resin system has a merit that the precise patterns can be obtained by UV exposure and aqueous development, so the essential point is to get the composition similar to PSR(photo solder resist) used for PCB process. In present research, we made the photopatternable resistor pastes using 8 kinds of epoxy acrylates and a conductive carbonblack (CDX-7055 Ultra), evaluated their developing performance, and then measured the resistance after final curing. To become developable by alkali-solution, epoxy acrylate oligomers with carboxyl group were prepared. Test coupons were fabricated by patterning copper foil on FR-4 CCL board, plating Ni/Au on the patterned copper electrode, applying the resistor paste on the board, exposing the applied paste to UV through Cr mask with resistor patterns, developing the exposed paste with aqueous alkali-solution (1wt% $Na_2CO_3$), drying the patterned paste at $80^{\circ}C$ oven, and then curing it at $200^{\circ}C$ during 1 hour. As a result, some test compositions couldn't be developed according to the kind of oligomer and, in the developed compositions, the measured resistance showed different results depending on the paste compositions though they had the same amount of carbonblack.