• 한국환경과학회지
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• 제10권1호
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• pp.47-58
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• 2001

According to the results of the groundwater quality investigation about 230 holes all over the country, the groundwater which was in excess of standard grows larger every year and closed holes increased to 23,457 holes in 1997 from 15,724 holes in 1996. This is the major reasons that water quality contamination, shortage of water quantity, increasing of salinity and so on. There are 7 groundwater salinization sources which are condisered as most important on a regional level. And among theses the Cheju Island groundwater salinization sources are (1) halite solution, (2) natural saline groundwater, (3) sea-water intrusion. The method of taking an isotopes is one of research methods of the origin of groundwater salinization and is used in so many studies because it has very high confidence. $^{18O}O, ^2H, ^3H, ^{14}C$ and so on in an isotopes are frequently used in the method of them. Consequently on this study we analyzed major ions and $^3H$ in groundwater, sea-water and rain of the eastern part of cheju island known as contaminated site from long time ago to examine the origin of groundwater salinization. Relation ratios of the major ions versus chloride ion shows similar tendency to sea-water. This indicates that sea-water entered the groundwater layer. And amount of $^3H$ in holes of the land side is higher than of the sea side. Relation of chloride ion versus $^3$H indicates negative character. Therefore we can think that the reason of groundwater salinization of this part is natural saline groundwater and halite solution by relation.

• Natural Product Sciences
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• 제16권3호
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• pp.164-168
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• 2010

High-performance liquid chromatographic method with diode-array detector and electrospray ionization with multi-stage tandem mass spectroscopy (HPLC/DAD/ESI-$MS^n$) was used to identify the major constituents in a methanolic extract of Eclipta prostrata. The chromatographic separation was performed on a C18 column. Acetonitrile-water was used as a mobile phase. HPLC/DAD/ESI-$MS^n$ allowed the characterization of constituents of E. prostrata, mainly triterpenoids (eclalbasaponin I, II, III, IV, VI), flavonoids (luteolin 7-O-glucoside, demethylwedelolactone, wedelolactone, luteolin, demetylwedelolactone sulfate, luteolin sulfate, apigenin sulfate) and phenolic acids (5-O-caffeoylquinic acid, 3, 4-O-dicaffeoylquinic acid, 3, 5-O-dicaffeoylquinic acid, 4, 5-Odicaffeoylquinic acid).

• 동의생리병리학회지
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• 제18권5호
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• pp.1418-1425
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• 2004

The water extract of Chongmyung-tang has been traditionally used for treatment of memory-disorder in oriental medicine. This study was designed to investigate the protective mechanisms of Chongmyung-tang on β-amyloid or H₂O₂-induced cytotoxicity in Neuro 2A cells. The water extract of Chongmyung-tang significantly reduced both β-amyloid or H₂O₂-induced cell death and apoptotic characteristics through reduction of intracellular peroxide generation. Also, it inhibited the mitochondrial dysfunction including the disruption of mitochondria membrane permeability transition(MPT) and the modulation in expression of Bcl-2 family proteins in H₂O₂-treated H9c2 cells. Furthermore, pretreatment of quercetin inhibited the activation of caspase-3, in turn, degradation of ICAD/DFF45 were completely abolished in H₂O₂-treated cells. Taken together, that data suggest that the protective effects of the water extract of Chongmyung-tang against β-amyloid induced oxidative injuries may be achieved through modulation of mitochondrial dysfunction.

• 대한화학회지
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• 제62권2호
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• pp.113-117
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• 2018

The basic hydrogel lens with addition of N,N-dimethylacrylamide (DMA) and N-methyl-N-vinylacetamide (NMV) were manufactured. The optical and physical characteristics of ophthalmic lens were evaluated by measuring water content, oxygen permeability (Dk), refractive index and optical transmittance. The water content & oxygen permeability (Dk) of sample containing Ref., DMA group and NMV group was in the average of 34.48%, 35.54~49.19% & $13.003{\sim}18.468{\times}10^{-11}(cm^2/sec)$($mlO_2/ml{\times}mmHg$) and 36.28~44.95% & $12.270{\sim}16.883{\times}10^{-11}(cm^2/sec)$ ($mlO_2/ml{\times}mmHg$), respectively. And also, refractive index of the sample containing Ref., DMA group and NMV group was in the average of 1.4350, 1.4330~1.4131 and 1.4335~1.4195, respectively. Standard hydrogel monomer containing DMA and NMV was expected to be used usefully as a material for fabricating hydrophilic functional ophthalmic lens.

• 동의생리병리학회지
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• 제18권3호
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• pp.774-782
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• 2004

The water extract of Dancheonhwan (DCH) has been used to treat ischemic brain and heart damage in oriental medicine. However, little is known about the mechanism by which the water extract of DCH rescues cells from ischemic damage. Therefore, this study was designed to investigate the protective mechanisms of DCH on the H₂O₂-induced toxicity in H9c2 cardiomyoblast cells. Treatment of H₂O₂ markedly decreased the viability of H9c2 cardiomyoblast in a dose-dependent and time-dependent manner. The nature of H₂O₂-induced toxicity of H9c2 cells resulted from apoptotic death confirmed with genomic DNA fragmentation. DCH increased the viability of H₂O₂-treated H9c2 cells by about 23%, and partially suppressed the genomic DNA fragmentation and PARP cleavage. H₂O₂ also activated caspase-3 protease and -9 protease, but not both caspase-6 protease and -8 protease. H₂O₂ induced the mitochondria dysfunction, including mitochondria membrane permeability transition (MPT) and cytosolic release of cytochrome c from mitochondria, which was prevented in part by pretreatment of DCH. N-acetylcystein (NAC), a free-radical scavenger, alone increased the viability of H₂O₂-treated H9c2 cells in a dose-dependent manner. Furthermore, the combination of NAC with DCH significantly increased the viability of the H₂O₂-treated H9c2 cells in a dose-dependent manner. These data indicate that DCH has the protective effect on ROS-induced apoptosis of cadiomyoblast H9c2 cells.

• 한국세라믹학회지
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• 제18권4호
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• pp.229-236
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• 1981

This study deals with the high temperature (600-135$0^{\circ}C$) properties of Kaolin-Phosphate-Water systems. Phosphoric acid, mono aluminum phosphate, mono ammonium phosphate, the mixture of phosphoric acid and mono aluminum phosphate, and the mixture of phosphoric acid and mono ammonium phosphate were used to characterize the M.O.R of the systems with to quantity of phosphates and firing temperature. Firing shrinkage, creeptest, DTA, TGA, and X-ray diffraction patterns were also measured in order to investigate the factors of strengthening. The resules of the experiments are as follows: 1. Linear shrinkage of kaolin-phosphate systems become larger as the firing temperature rise, and generally in the firing temperature of $600^{\circ}C$ and 100$0^{\circ}C$ the test pieces with phosphate binder show larger then Kaolin-Water system in linear shrinkage and reversed trends were found at 120$0^{\circ}C$ and 135$0^{\circ}C$. 2. Cold M.O.R. of kaolin-phosphate systems show higher trends in strength as the firing temperature rise. Comparing M.O.R. of test pieces after firing at 135$0^{\circ}C$, the mixture of phosphoric acid-mono aluminum phosphate, and phosphoric acid mono ammonium phosphate systems show higher strength than kaolin-mono aluminum phosphate system which widely used, and it shows highest strength when the mole ratio of phosphoric acid and mono ammonium phosphate is 1:1 among the test pieces of kaolin-phosphate systems. 3. The refractoriness of kaolin-phosphate systems are more deteriorated than Kaolin-Water system, and generally, the more addition of phosphate, the lower the refractoriness, however in the range of 4-8% phosphate addition, the difference of the fusion temperature is about 7$0^{\circ}C$. 4. The test pieces of T1 and T2 in creep test were same or even higher than kaolin-water system when 6% of phosphoric acid-mono ammonium phosphate was added to kaolin. 5. In case where the phosphoric acid-mono ammonium phosphate was added to kaolin in mole ratio 1:1 the cold M.O.R., after firing at 135$0^{\circ}C$, refractoriness and $T_2$ in creep test show better results than kaolin-mono-aluminum phosphate system which is widely used. 6. Phosphoric acid and mono ammonium phosphate react with kaolin in temperature over 100$0^{\circ}C$, and it forms aluminum phosphate.

• 상하수도학회지
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• 제18권4호
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• pp.529-536
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• 2004

Innovated technique to inactivate microorganisms has been developed. This technique uses plasma discharge in 2-phase (Air-Water). Dielectric Barrier (two phase) Discharging system is able to produce new oxidants for microorganisms. Products from discharging are $HNO_2$, $NO_2{^-}$, $HNO_3$, $NO_3{^-}$ and ozone but many other radicals can be generated as well. DBD water has low concentration of ozone (about 0.5mg/L), $NO_2{^-}$, $NO_3{^-}$ (about 10mg-N/L, 20mg-N/L respectively) and lots of $H^+$. These products play an important role in oxidation. Oxidation power by KI titration methods is approximately equivalent to $50mg-O_3/L$. Surprisingly stored DBD water could oxidize KI and maintain stable pH (about pH3) even after several days. Stored DBD water for 5 days has also more than 4log disinfection power to E. coli. However, DBD water cannot be used for drinking water directly due to it's toxicity. Additional process to neutralize pH and decrease toxicity must be applied.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.29-38
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• 2005

It is important to understand groundwater conditions such as recharge, flow and hydrochemical process occurred within an aquifer for groundwater protection and groundwater resource management. Groundwater from the Triassic Sherwood Sandstone aquifer of North Yorkshire has been used for industrial purposes and domestic water supply. Tn order to understand the processes affecting groundwater chemistry and identify the sources of high chloride, sulphate and nitrate concentrations hydrochemical and isotopic measurements were carried out. Hydrochemical and isotopic measurements indicated that five groundwater types exist within the Sherwood Sandstone aquifer of study area. The results of hydrochemical and isotopic measurements showed that older groundwaters have different hydrochemical and isotopic characteristics from recent recharge water. It was also found that water-rock interactions are the dominant mechanism controlling the ${\delta}^{13}C$ composition of dissolved inorganic carbon, the ${\delta}^{34}S\;and\;{\delta}^{18}O$ composition of dissolved sulphate and the strontium isotope ratios ($^{87}Sr/^{86}Sr$) in recent recharge water and old groundwater. Several abstraction boreholes within the Selby wellfield have been contaminated by saline water. The isotopic data of saline groundwater samples taken from these abstraction boreholes indicate that saline waters are derived from the dissolution of the Triassic evaporites within the Mercia Mudstone.

• 분석과학
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• 제18권2호
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• pp.120-129
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• 2005

VOC는 대기오염의 주원인으로서 인식되어왔다. 촉매산화는 저온에서 높은 효율을 나타내기 때문에 VOCs 제거를 위한 가장 중요한 처리기술중 하나이다. 이 연구에서는 $TiO_2$ 담체에 Pt, Ir 그리고 Pt-Ir을 담시지켜 촉매를 제조하였다. 금속 분산에 따르면 $H_2O-H_2$ 처리방법이 사용되었고, 반응물로서 Xylene,Toluene 그리고 MEK을 사용하였다. 단일 또는 두 가지 이상의 촉매들은 함침법에 의해 준비하였고, XRD, XPS, TEM 분석을 통하여 특성화하였다. 그 결과 Pt 촉매는 Ir 촉매에 비해 더 높은 전환율을 나타내었고, Pt-Ir 촉매는 가장 높은 전환율을 나타내었다. $H_2O-H_2$ 처리한 촉매들은 처리하지 않은 것보다 VOCs 전환율이 높았다. VOCs 산화에서, Pt-Ir 촉매는 다양한 활성점을 나타내었고 그것은 Pt의 metal 영역을 강화시켰다. 따라서 두 가지 금속으로 이루어진 촉매가 단일 금속으로 이루어진 촉매에 비해 VOCs 전환율이 더 높았다. $H_2O-H_2$ 처리가 Pt 입자의 분산에서 형태에 영향을 미쳤다. 동역학적으로 VOCs 산화는 1차 반응이다. $H_2O-H_2$ 처리한 촉매들의 활성화에너지가 처리하지 않은 것들보다 낮았다. 이 연구에서 Pt에 Ir을 소량첨가함으로써 VOCs 산화반응에 효과적이었다.

• 한국광학회지
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• 제15권1호
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• pp.1-5
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• 2004

분리막을 이용한 산소-18 분리실험에서 분리된 시료의 동위원소 성분비 분석을 위해 다이오드 레이저 흡수분광장치를 구성하였다. 흡수신호의 신호 대 잡음비를 높이기 위해 lock-in증폭기를 사용한 파장변조 분광법을 채택하였다. 레이저의 주파수 변조폭 최적화와 FFT 저역통과 필터링을 통해 다중반사흡수셀에서 발생하는 간섭무늬 잡음을 줄였다. 산소-18에 대한 흡수분광장치의 최대편차는 $\pm$4$\textperthousand$로 측정되었다.