• 한국식품저장유통학회지
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• 제9권1호
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• pp.74-77
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• 2002

솔잎으로부터 항균, 항산화효과 등이 입증된 바 있는 polyphenols 분리.정제를 실시하였다. 이 물질의 분리를 위한 추출용매로는 열수, EtOH, IPA를 사용하였는데, 각각의 용매에 의하여 분리된 polyphenols의 수율 및 순도는 각각 9.84, 11.61, 14.36% (w/w) 및 83.83, 82.64, 81.52%였다. 추출조건은 솔잎분말 대비 약 7배 (w/v)에 해당하는 용매를 가하고 85$^{\circ}C$에서 6시간 동안의 처리로 추출이 가능하였다. 분리된 polyphenols의 정제는 formamide-active carbon(1:1, w/w)을 충진한 column을 통과시켜 정제한 다음 농축, 분무건조 하고, 이 분말에 식품첨가물용 n-hexane(1:2.5, w/v)을 가하여 1시간 동안 추출하여 지방성분을 추출, 제거하고 풍건하여 각각의 시제품을 얻었다. Polyphenols의 추출용매로는 열수, EtOH, IPA 중 수율과 순도를 동시에 고려할 때, 상호간의 장단점이 있었는데, 수율과 순도간에는 정의 반비례 관계가 성립하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.360-360
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• 2008

Steelmaking industry is widely known to use a lot of water and same amount of wastewater is generated. Although toxicity of wastewater from Steelmaking industry is low, it contains an amount of various organic materials and Fe-Oxides. It is important to recycle the wastewater because of water shortages and water pollution. In general, large-scale equipment is necessary to process the wastewater. On the other hand, superconducting high gradient magnetic separation (HGMS) system can process the wastewater in the small space. Superconducting HGMS system that had a purpose to purify the wastewater was assembled. Cryo-cooled Nb-Ti superconducting magnet was used for magnetic separator. This system can operate continuously because contaminated filters can keep on returning after cleaning. The various magnetic seeding reactions were investigated to increase the reactivity of coagulation. Filter cleaning system was developed to decrease the quantity of clean water. This research was supported by a grant from Korea Electrotechnology Research Institute, Republic of Korea.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1261-1265
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• 2006

본 연구에서는 수질정화체 설치에 따른 농업용 배수로의 수리적 안정성 검토를 위하여 수리모형시험을 실시하였으며, 수질정화체의 단면적 및 위치를 변화시켜 수리적 안정성을 검토하였다. 유량이 일정한 상태에서 수질정화체의 단면적을 변화시켜 수심 및 유속을 측정하여 수질정화체의 단면적에 대한 농업용 배수로의 수리적 안정성을 알아보았으며, 단면적을 고정시킨 상태에서 수질정화체의 위치변화에 따른 수심 및 유속을 측정함으로써 수질정화체 간의 간격에 의한 배수로의 수리적 안정성을 고찰하였다. 수심과 유속은 수질정화체를 기준으로 상류 및 하류에 대하여 측정함으로서 수질정화체 전 후의 변화상태를 알아보았다. 수질정화체의 단면적이 증가함에 따라 상류 수심이 하류 수심에 비하여 증가하며, 유속변화가 심한 것을 확인하였다. 또한 수질정화체의 간격이 가까워짐에 따른 유속 및 수심 변화를 알아보았다. 본 연구에서 나온 수리적 변화는 수로내의 장애물에 대한 기존 공식 중에 D'Aubuission식과 유사한 것으로 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.650-654
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• 2008

친환경 공법의 수리적인 안전성 검토는 식생 및 자연재료의 물리적 특성, 하천의 수리 수문학적 특성, 유사특성과 이들의 상호관계 등에 대한 분석이 요구되며, 이에 선행하여 분석에 이용되는 장기간의 충분한 자료가 구축되어 있어야 한다. 그러나 우리나라의 경우 이러한 자료는 부족한 실정이며, 주로 시범구간을 통한 제한된 자료만이 이용되고 있을 뿐이므로 수리학적 치수방재적 측면에서 친환경 공법의 안전성 평가에 있어 많은 어려움을 겪고 있다. 본 연구에서 수질정화체의 배치 변화를 통한 수치해석 통하여 수심 및 유속분포를 비교 분석하여 수로의 3차원적 흐름특성을 파악하고, 실제 대상수로에 수질정화체를 설치하여 수로의 수리적 안정성을 연구하였다. FLOW-3D와 수리모형시험 그리고 대상수로 모니터링을 각 경우에 따라 유속, 수위를 측정하여 다양한 조건에 대한 흐름 특성을 연구하였다.

• 상하수도학회지
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• 제30권5호
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• pp.533-543
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• 2016

Supplying clean and safe water to people is facing both quantitative and qualitative challenges. Due to climate change, access to freshwater becomes increasingly difficult, while pollution from various sources decreases the public trust in water quality. Managed aquifer recharge (MAR) which stores and uses surface water in aquifer is receiving attention as a new technology to secure freshwater. Recently, there is a global expansion in the attempt to combine general purification plants and hazard analysis and critical control point (HACCP) which manages all the process from raw material to consumer for food safety. This research is about an attempt to apply HACCP to the drinking water supply process using MAR to secure both quantity and quality of drinking water. The study site is a MAR plant being constructed in the downstream area of the Nakdong River Basin, South Korea. The incorporation of HACCP with MAR-based water supply system is expected to enhance the safety and reliability of drinking water.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.56-56
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• 2010

Single-walled carbon nanotubes (SWCNTs) have attracted much attention as a promising material for transparent conducting films (TCFs), due to their superior electrical conductivity, high mechanical strength, and complete flexibility as well as their one-dimensional morphological features of extremely high length-to-diameter ratios. This study investigated three kinds of SWCNTs with different purities: as-produced SWCNTs (AP-SWCNTs), thermally purified SWCNTs (TH-SWCNTs), thermally and acid purified SWCNTs (TA-SWCNTs). The purity of each SWCNT sample was assessed by considering absorption peaks in the semiconducting ($S_{22}$) and metallic ($M_{11}$) tubes with UV-Vis NIR spectroscopy and a metal content with thermogravimetric analysis (TGA). The purity increased as proceeding the purification stages from the AP-SWCNTs through the thermal purification to the acid purification. The samples containing different contents of SWCNTs were dispersed in water using sodium dodecyl benzensulfate (SDBS). Aqueous suspensions of different purities of SWCNTs were prepared to have similar absorbances in UV-Vis absorption measurements so that one can make the TCFs possess similar optical transmittances irrespective of the SWCNT purity. Transparent conductive SWCNT networks were formed by spraying an SWCNT suspension onto a poly(ethyleneterephthalate) (PET) substrate. As expected, the TCFs fabricated with AP-SWCNTs showed very high sheet resistances. Interestingly, the TH-SWCNTs gave lower sheet resistances to the TFCs than the TA-SWCNTs although the latter was of higher purity in the SWCNT content than the former. The TA-SWCNTs would be shortened in length and be more bundled by the acid purification, relative to the TH-SWCNTs. For both purified (TH, TA) samples, the subsequent nitric acid ($HNO_3$) treatment greatly lowered the sheet resistances of the TCFs, but almost eliminated the difference of sheet resistances between them. This seems to be because the electrical conductivity increased not only due to further removal of surfactants but also due to p-type doping upon the acid treatment. The doping effect was likely to overwhelm the effect of surfactant removal. Although the nitric acid treatment resulted in the similar. electrical properties to the two samples, the TCFs of TH-SWCNTs showed much lower sheet resistances than those of the TA-SWCNTs prior to the acid treatment.

• 한국기계기술학회지
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• 제20권6호
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• pp.858-864
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• 2018

Graphene oxide (GO) laminate is a new promising material for water purification system, which has extraordinary permeability only for water molecule. It consists of numerous nano-channels, in which water molecules could be nano-confined, resulting in slip of the molecules for very fast transportation speed. In this study, water penetration rate via different thickness of GO membrane according to driven pressures are measured experimentally, so that speed of water molecules and permeability are evaluated. Generally, water penetration rate via a membrane with macroscopic-sized channel increases linearly with pressure difference between up and bottom side of the membrane, but that via GO membrane approaches asymptotic value (i.e. saturation) as like a log function. Moreover, the permeability of GO membrane was observed in inverse proportion to its thickness. Based on the experimental observations, a correlation for volume flux via GO membrane was suggested with respect to its thickness and external pressure difference.

• KSBB Journal
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• 제29권1호
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• pp.9-21
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• 2014

One of the most abundant microalgaes, diatom is characterized by its unique cell wall structures composed of nano-patterned silica. Due to its highly ordered porosity, these silica frustules, which are found as sediments called diatomite, were used as a cheap adsorption material for water purification. Recently, new emerging nanotechnology compels many researchers to have interest in such diatom's unique properties (eg, nano-scale mesoporosity, photo luminescence, light transparency, etc.) as biogenic inorganic materials as well as the biomass resource (conventional usage of microalgae). In this review, we will focus on the current knowledge about the diatoms research and the possibility of its applications.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.357-361
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• 2001

The possibility of producing Cr$_2$O$_3$powder from waste magnesia-chromium refractory was investigated by sulfuric acid reaction, alkali fusion, water leaching & purification and heat treatment. The effects of temperature, the amount of NaOH added and the flow rate of air on chromium extraction efficiency in an alkali fusion step were investigated. The fusion product was leached with methanol to solve free-NaOH, and then leached with water to produce a Na$_2$CrO$_4$solution. The purity of chrome(Ⅵ) oxides, prepared both from monochromate with an impurity content and monochromate purified with $CO_2$were also examined. The purified monochromate solution was reduced from Cr(Ⅵ) to Cr(III) with NaHSO$_3$solution. The reduced solution was neutralized with NaOH to produce Cr(OH)$_3$. Water washing was treated to eliminate Na$_2$SO$_4$from neutralized Cr(OH)$_3$slurry. The washed Cr(OH)$_3$was dried and thermally treated to produce Cr$_2$O$_3$powder. The properties like lightness and hue of Cr$_2$O$_3$fabricated in this study were L=47.47, a=-14.40 and b=17.21.

• 한국작물학회지
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• 제51권spc1호
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• pp.103-106
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• 2006

Anthocyanins are water-soluble glycosides and acylglycosides of anthocyanidins, having different color variations due to its substitution patterns. Anthocyanins, present in various fruits, vegetables and crops as natural colorant, have been well characterized for its bioactive properties, anti-oxidant, anti-cancer, anti-proliferative and anti-inflammatory properties. During extraction and purification, the factors, such as pH, temperature, oxygen, light, enzymes, nucleophilic agents, sugar derivatives and co-pigments, have affected on anthocyanin stability. For this reason, the extraction method should be thoroughly checked for the qualitative/quantitative analysis of anthocyanin in particular plant material. To identify the optimum extraction method of cyanidin-3-glucoside, major anthocyanin of dark purple-colored grains, Oryza sativa cv. Heugjinjubyeo, Phaselous vulgaris, Phynchosia gngularis, Sesamum indium, Rhynchosia nulubilis and Lablab purpureus, reversed-phase HPLC analysis using solvent system of acetonitrile, methanol and water were accomplished.