• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
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• pp.115.1-115.1
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• 2000

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.127-130
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• 1999

Physical properties and microstructure of slag blended cement were investigated to evaluate the influence of sulphates and chlorides. The compressive strength developed as high chloride content dust and gypsum added and accordingly the microstructure modification was showed. The deviation of pore size distribution and hydrates was also observed. From these results we discussed optimum condition of gypsum and high chloride content dust leading to physical properties in this study.

• Membrane and Water Treatment
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• 제2권3호
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• pp.147-158
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• 2011

Membrane distillation process was used for desalination of hot (333 K) geothermal water, which was applied in the plant producing heating water. The investigated water contained 120 g salts/$dm^3$, mainly NaCl. The mineral composition was studied using an ion chromatography method. The obtained rejection of solutes was closed to 100%, but the small amounts of $NH_3$ also diffused through the membrane together with water vapour. However, the composition of obtained distillate allowed to use it as a makeup water in the heating water system. The geothermal water under study was concentrated from 120 to 286 g NaCl/$dm^3$. This increase in the solution concentration caused the permeate flux decline by a 10-20%. The geothermal water contained sulphates, which was subjected to two-fold concentration to achieve the concentration 2.4-2.6 g $SO{_4}{^{2-}}/dm^3$ and the sulphates then crystallized in the form of calcium sulphate. As a results, an intensive membranes scaling and the permeate flux decline was observed. The XRD analysis indicated that beside the gypsum also the NaCl crystallites were deposited on the membrane surfaces. The fresh geothermal water dissolved the mixed $CaSO_4$ and NaCl deposit from the membrane surface. This property can be utilized for self-cleaning of MD modules. Using a batch feeding of MD installation, the concentration of geothermal water was carried out over 800 h, without significant performance losses.

• Natural Product Sciences
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• 제4권4호
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• pp.221-225
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• 1998

A novel flavonol trisulphate, quercetin 7-methyl ether $3,3',4'-tri-O-KSO_3$ was isolated from the fresh leaves of Tamarix amplexicaulis (Tamaricaceae) along with the known flavonol mono sulphates, quercetin $3-O-KSO_3$ and quercetin 4'-methyl ether $3-O-KSO_3$. Structures were achieved through conventional analytical methods, including electrophoretic analysis and confirmed by FAB-MS and NMR spectroscopy.

• 한국대기환경학회지
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• 제7권3호
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• pp.197-202
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• 1991

It is observed that the outbreak of dust storms (yellow sand) from Northern China and Mongolia occurs a few times in April 1988 and 1990. It is found that a dust storm initiated with strong gusty winds after the passage of a cold front, particularly after defrost of the ground surface of a source region in the early spring. According to meteorological chart, satellite images and trajectory analyses, dust clouds invaded Korea in April 1988 and 1990 were landing in the sink area after 2 $\sim$ 4 days travelling for 2,000 $\sim$ 3,000 km from a source region. It was also observed that in the west coast total suspended particulated (TSP) were 100 $\sim$ 200 $\mug m^{-3}$ and sulphates $(SO_4=)$ were 3 $\sim$ 10 $\mug m^{-3}$. These values clearly exceed the concentrations of a background level measured in the Arctic and Atlantic Ocean. Trajectory analyses and meteorological analyses suggest that the high values occurred with prevailing westerly flows coming from anthropogenic sources in China. High concentrations of air pollutants occurred in the backside of an anticyclone and in the area "col".col".uot;.

• Natural Product Sciences
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• 제6권2호
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• pp.91-95
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• 2000

A phytochemical investigation of the aqueous ethanolic flower extract of Tamarix tetragyna led to the isolation and characterization of the hitherto unknown conjugates, kaempheride 3,7-dipotassium sulphate and kaempferol 3,4'-dipotassium sulphate as well. Twelve known flavonol compounds, including kaempheride 3-potassium sulphate and kaempheride $3-O-{\beta}-glucuronide$ were also isolated and identified. $^1H-\;and\;^{13}C-NMR$ spectra for the known kaempheride derivatives have been recorded and assigned for the first time. Structures of all compounds were established by conventional methods of analysis and confirmed by $^1H-,\;^{13}C-NMR$ and mass spectral analysis.

• Fibers and Polymers
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• 제7권2호
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• pp.105-111
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• 2006

Coating the fibre surface by in situ oxidative chemical polymerisation of polypyrrole (using $FeCl_3$ as oxidant) is a readily industrial applicable way to give electrical properties to wool with good ageing stability [1], although pre-treatments are required to avoid damage of the cuticle surface due to the acidic condition of the process. FT-IR and EDX analysis reveal that organic sulphonates and sulphates, used as dopants, are absorbed by wool, while chlorine ions are preferably embedded on the polypyrrole layer. The resulting electrical conductivity seems mainly due to the presence of chlorine as counter-ion of polypyrrole; nevertheless, the presence of arylsulphonate in the polymerisation bath increases the electrical conductivity of the coating layer.

• 한국표면공학회지
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• 제32권3호
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• pp.410-415
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• 1999

The adhesion strength of sputtered copper films to Inconel substrates has been studied using the scratch test. The effects of substrate treatments before deposition such as chemical or ion bombardment etching were investigated by means of a mean critical load derived from a Weibull-like statistical analysis. It was found that the mean critical load was very weak unless the amorphous layer produced by mechanical polishing on the substrate surface was eliminated. Chemical etching in a nitric-hydrochloric acid bath was shown to have practically no effect on the enhancement of the adhesion. In contrast, the addition in this bath of nickel and copper sulphates allowed removal of the amorphous layer and an increase in the values of the mean critical load. However, it was observed that excessive chemical etching could cancel out the mean critical load enhancement. The results obtained in the case of ion bombardment etching pretreatments could be far higher than those obtained with chemical etching. Moreover, for a sufficiently long period of ion bombardment etching, the adhesion strength was so high that it was impossible to observe evidence of an adhesion failure.

• 한국광물학회지
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• 제17권1호
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• pp.37-47
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• 2004

대구광역시에 위치한 달성광산의 폐광석과 하천수에 형성된 황산염 광물인 명반석과 슈베르트마나이트의 특징과 수질변화를 통하여 산화환경하에서의 환경지구화학적 의미를 고찰하였다. 산성광산배수는 하류로 갈수록 pH가 감소하는 특징을 보이는데, 이는 슈베르트마나이트의 형성에 크게 영향을 받는다. Al광물들의 침전작용에 의하여 하천수로부터 Al이 제거되는데, 그 중에서 가장 중요한 Al-황산염광물인 명반석은 Al의 가수분해 상수인 $pK_1$ 이상의 높은 pH환경에서 잘 형성된다. 명반석은 SEM하에서 뚜렷한 구상의 결정체로서 슈베르트마나이트와 수반되고, 높은 포화지수를 나타낸다. 지표환경에 노출된 폐금속광석에서는 산화작용으로 인하여 다양한 이차광물이 기존의 광물표면에 성장하거나, 피복 되어 있다. 명반석은 특징적으로 구형, 싸리버섯 같은 정벽(botrytis-like habit), 또는 방사상의 결정집합체로 나타난다. 또한, natroalunite를 수반하거나, 이 둘의 물리적 혼합체(mixture)를 형성한다. 본 산성광산배수의 유해성분들이 하천을 따라 다소 저감되기는 하나, 슈베르트마나이트가 지속적으로 형성되므로 하류로 갈수록 pH가 감소한다. 그러므로 하상침천물은 쉽게 다시 용해될 수 있다. 따라서, 본 AMD에서 자연저감효과는 미미하며, 여전히 잠재적인 위해 요소를 가지고 있다.

• Advances in concrete construction
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• 제4권2호
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• pp.107-121
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• 2016

This concrete is one of the most versatile construction material widely used for almost a century now. It was considered to be very durable material and required a little or no maintenance since long time. The assumption is very true, except when it is subjected to highly aggressive environments. The deterioration of concrete structures day by day due to aggressive environment is compelling engineers to assess the loss in advance so that proper preventive measure can be taken to achieve required durability to concrete structures. The compounds present in cement concrete are attacked by many salt solutions and acids. These chemicals are encountered by almost all concrete structures. The present study has been undertaken to investigate the effect of attack of chlorides and sulphates with varying severity on compressive strength of ground granulated blast furnace slag (GGBFS) concrete after immersion in salt solution for 28 days. The results indicate that the durability of GGBFS concrete increases with the increase in percentage replacement of cement by GGBFS for 20% and then gradually decreases with increases in percentage of GGBFS with cement (as in the study for 40% and 60%). Also there is increase in strength of GGBFS concrete with increase in age. Thus the durability of concrete improves when GGBFS is added as partial replacement of cement. In this study the strength of GGBFS concrete is less affected by chemicals as compared to conventional concrete when exposed to aggressive environment.