• Bulletin of the Korean Chemical Society
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• 제32권7호
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• pp.2217-2221
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• 2011

We investigated the selective deoxyribonucleic acid (DNA) adsorption on layered double hydroxide (LDH) nanoparticles via studying the interaction between positively charged LDH nanoparticle as adsorbent and negatively charged adsorbates such as methyl orange (MO), fluorescein (FL), and DNA strands. The size controlled LDH $(Mg_{0.78}Al_{0.22}(OH)_2(CO_3)_{0.11}{\cdot}mH_2O)$ was prepared by conventional coprecipitation method, followed by the hydrothermal treatment. According to the adsorption isotherms, the adsorbed amounts of MO and FL were similar, however, that of DNA were much larger. The adsorption behaviors were well fitted to Freundlich adsorption model. The concentration dependent adsorption behavior on LDH surface was described in order to verify the selective DNA separation ability. The result showed that the LDH has advantages in selective adsorption of DNA competing with single molecular anions.

• 멤브레인
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• 제24권5호
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• pp.409-415
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• 2014

본 연구에서는 석유화학공정 중에서 많은 에너지를 소비하는 NCC(Naphtha Cracking Center) $C_3$ splitter를 대신하여 에너지 소비가 적고 친환경 공정인 막분리법을 이용하여 프로필렌/프로판의 분리특성을 예측하고자 한다. 막소재로는 프로필렌/프로판 분리에 대하여 우수한 성능을 나타내는 것으로 잘 알려진 촉진수송막을 사용하였다. 실험에 사용된 촉진수송막은 한양대학교에서 제조한 은나노입자가 함유된 VP/$AgBF_4$/TCNQ 용액을 에어레인에서 다공성 폴리이서이미드 중공사에 얇게 코팅하여 소형 중공사 막모듈로 제작하였다. 제작된 촉진수송막 모듈의 투과성능을 평가하기 위하여 프로필렌과 프로판에 대한 단일기체 테스트를 진행하였다. 분리막의 투과현상을 예측하기 위하여 전산모사 프로그램을 개발하였다. 개발된 전산모사 프로그램에 단일기체 테스트를 통해 얻어진 투과도와 선택도를 이용하여 95/5 vol% $C_3H_6$ / vol% $C_3H_8$ 혼합가스를 공급하였을 경우, 공급측 및 투과측 압력 변화에 따른 투과측 프로필렌의 농도가 99.5 vol%를 유지하는 단일 분리막 공정을 설계하였다.

• 멤브레인
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• 제24권6호
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• pp.417-422
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• 2014

본 연구에서는 Poly(ethylene oxide) (PEO)/Ag Nanoparticles (NPs)/7,7,8,8-Tetracyanoquinodimethane (TCNQ) 분리막 시스템을 제조하여 기존의 PEO/Ag NPs/p-Benzoquinone (p-BQ) 복합체 분리막보다 더 향상된 성능을 보이는 고투과성올레핀 촉진수송 나노복합체 분리막을 얻고자 하였다. 고분자 지지체 PEO와 은 나노 입자 전구체 $AgBF_4$는 1 대 0.4 몰비로 고정하고 전자 수용체인 TCNQ 함량은 다양하게 조절하였으며 1/0.4/0.004 몰비에서 가장 높은 올레핀 분리막 성능을 확인하였다. 따라서 이 비율에서 long-term test를 진행하였고 초반에는 투과도 약 23 GPU, 선택도 약 6 (프로필렌/프로판)의 수치를 보였으나 32시간 만에 투과도는 약 6 GPU, 선택도는 약 2 (프로필렌/프로판)로 감소하는 것을 확인하였다.

• Advances in nano research
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• 제10권3호
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• pp.295-312
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• 2021

A new ionic liquid functionalized magnetic silica nanoparticle was synthesized and characterized and tested as an adsorbent. The adsorbent was used for magnetic solid phase extraction on ICP-MS method. Simultaneous determination of precious metal Au has been addressed. The method is simple and fast and has been applied to standard water and surface water analysis. A new method for separation/analysis of trace precious metal Au by Magnetron Solid Phase Extraction (MSPE) combined with ICP-MS. The element to be tested is rapidly adsorbed on CoFe2O4@SiO2@[BMIM]PF6 composite nano-adsorbent and eluted with thiourea. The method has a preconcentration factor of 9.5-fold. This method has been successfully applied to the determination of gold in actual water samples. Hydrophobic Ionic Liquids (ILs) 1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6) coated CoFe2O4@SiO2 nanoparticles with core-shell structure to prepare magnetic solid phase extraction agent (CoFe2O4@SiO2@ILs) and establish a new method of MSPE coupled with inductively coupled plasma mass spectrometry for separation/analysis of trace gold. The results showed that trace gold was adsorbed rapidly by CoFe2O4@SiO2@[BMIM]PF6 and eluanted by thiourea. Under the optimal conditions, preconcentration factor of the proposed method was 9.5-fold. The linear range, detection limit, correlation coefficient (R) and relative standard deviation (RSD) were found to be 0.01~1000.00 ng·mL-1, 0.001 ng·mL-1, 0.9990 and 3.4% (n = 11, c = 4.5 ng·mL-1). The CoFe2O4@SiO2 nanoparticles could be used repeatedly for 8 times. This proposed method has been successfully applied to the determination of trace gold in water samples.

• Journal of Dairy Science and Biotechnology
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• 제22권1호
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• pp.1-12
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• 2004

Nanofood is advanced functional food which food industry and food scientist try to develop process foods in near future. To be developed nanofood, nanofood materials are needed, such as biodegradable nanosphere material, biotechnical nanofood material, and protein and nanofood material. There are some food industrial applications with nanotechnology, such as nanoencapsulation, nanomolecule making, nanoparticle and powder making, nano separation, and nano extration. We can find several nanofoods and nanofood materials on the market. In addition, dairy industry is also in the first step for the development of nanofunctional food. However, nanoencapsulations of lactase, iron, vitamin C, isoflavone are developed for functional milk. Dairy industry needs various nanofood materials to be advanced functional dairy products.

• Mass Spectrometry Letters
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• 제6권4호
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• pp.85-90
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• 2015

This article reviews recent analytical techniques using inductively coupled plasma-mass spectrometry (ICP-MS) immunoassay for clinical and bio analysis. We classified the techniques into two categories, direct and indirect analysis, which depend upon a guideline of whether tagging materials are used or not. Direct analysis is well known, and generally used in conjunction with various other techniques, such as laser ablation, chromatographic separations, etc. Recently, indirect analysis using tagging elements has intensively been discussed because of its importance in future applications to bio and clinical analysis, including environmental and food industries. The method has shown advantages of multiplex detection, excellent sensitivity, and short analysis time owing to signal amplification and magnetic separation. Now, it expands the application field from small biomolecules to large cells.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.67.2-67.2
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• 2012

Graphene is expected to have a significant impact in various fields in the foreseeable future. For example, graphene is considered to be a promising candidate to replace indium tin oxide (ITO) as transparent conductive electrodes in optoelectronics applications. We report the tunability of the wavelength of localized surface plasmon resonance by varying the distance between graphene and Au nanoparticles [1]. It is estimated that every nanometer of change in the distance between graphene and the nanoparticles corresponds to a resonance wavelength shift of ~12 nm. The nanoparticle-graphene separation changes the coupling strength of the electromagnetic field of the excited plasmons in the nanoparticles and the antiparallel image dipoles in graphene. We also show a hysteresis in the conductance and capacitance can serve as a platform for graphene memory devices. We report the hysteresis in capacitance-voltage measurements on top gated bilayer graphene which provide a direct experimental evidence of the existence of charge traps as the cause for the hysteresis [2]. By applying a back gate bias to tune the Fermi level, an opposite sequence of switching with the different charge carriers, holes and electrons, is found [3]. The charging and discharging effect is proposed to explain this ambipolar bistable hysteretic switching.

• 한국응용과학기술학회지
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• 제21권4호
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• pp.380-387
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• 2004

The preparation of $CaSO_4$ nanoparticle by vesicles formed spontaneously in cationic OTAC and anionic ADS mixed surfactant solution whose ratio is 0.3/0.7 is investigated. Added electrolytes for preparing nanoparticles reduce vesicle size about 200-300 nm comparing with that of pure vesicle whose size is 700-800 nm by DLS. The core of vesicles has 200 nm size and acts as nanoreactors which same size of monodisperse $CaSO_4$ nanopaticles are formed. Although $CaSO_4$ particles are formed at the outer of vesicles, they are very large and amorphous. The formed particles are identified with XRD analysis after separation due to coinciding with $CaSO_4$ particles.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1568-1572
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• 2010

The selective isolation of specific proteins from complex protein mixtures by nanoparticles is reported. Glutathionemodified superparamagnetic nanoparticles were used to purify specific proteins fused with glutathione S-transferase via enzyme-substrate interactions. They demonstrated greatly improved selectivity and efficiency over micron sized capturing beads. The ultra-specific enrichment of target proteins was confirmed by both SDS-PAGE and LC/MS/MS experiments.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.957-960
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• 2003

A method of preparation of magnetite nanoparticles in ordered systems, as in vesicle and microemulsion, consisting of soybean lecithin and water has been introduced. The size of magnetite grain was controlled by the content of soybean lecithin and size of liposomes in the systems. It was found by experiment that magnetite nanoparticles were formed inside the double layer vesicles. The magnetite nanoparticles were separated by magnetic separation and centrifugation and the dispersion of the magnetite nanoparticles prepared at 10% (w/w) soybean lecithin was particularly stable. The formation of pure magnetite nanoparticles was confirmed by analyses of XRD and electron diffraction pattern.