• Title/Summary/Keyword: nano complex

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Dielectric Properties of Epoxy/Micro/Nano Alumina Multi-Composites (에폭시/마이크로/나노알루미나 혼합된 멀티-콤포지트의 유전 특성)

  • Park, Jae-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.9
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    • pp.565-570
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    • 2016
  • In this work, the complex permittivity of epoxy resins is measured. Epoxy resins, epoxy with micro size fillers and epoxy with micro+nano alumina composites have been evaluated for dielectric properties according to frequency variation. The dielectric spectroscopy measurement and analyses are carried out in the frequency range of $10^{-2}Hz$ to 1MHz and constant to room temperature. The results of dielectric loss suggest that significant improvement in the electrical performance can be expected by using samples containing nano and micro fillers mixture when compared to materials containing only microfillers. As the result, we verified the specific characteristics of dielectric permittivity and dielectric loss namely, relative permittivity become low with improving dispersibility of nano+micro mixture composites and become rise with agglomerate of nano particles.

New Design and Synthesis of Donor-Acceptor units by Introducing Boron Based to Non-Boron based Semiconductor for high Voc OPV

  • Ryu, Ka Yeon;Cho, Kyuwan;Kim, Won-Suk;Kim, Kyungkon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.432.2-432.2
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    • 2016
  • A new A-D-A type (Acceptor-Donor-Acceptor) conjugated based on pyridine-borane complex (Donor), non-boron fluorine (Donor) and 2,5-bis(alkyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (DPP) (Acceptor) were designed and synthesized via Pd-catalyzed Suzuki cross-coupling reaction. The synthesized boron based complex exhibited high electron affinity, which indicates deep HOMO energy levels and good visible absorption led to their use as donors in BHJ (bulk heterojunction) solar cells. Inverted devices were fabricated, reaching open-circuit voltage as high as 0.91eV. To probe structure-property relationship and search for design principle, we have synthesized pyridine-boron based electron donating small molecules. In this study, we report a new synthetic approach, molecular structure, charge carrier mobility and morphology of blended film and their correlation with the photovoltaic J-V characteristics in details.

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Label-free and sensitive detection of purine catabolites in complex solutions by surface-enhanced raman spectroscopy

  • Davaa-Ochir, Batmend;Ansah, Iris Baffour;Park, Sung Gyu;Kim, Dong-Ho
    • Journal of the Korean institute of surface engineering
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    • v.55 no.6
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    • pp.342-352
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    • 2022
  • Purine catabolite screening enables reliable diagnosis of certain diseases. In this regard, the development of a facile detection strategy with high sensitivity and selectivity is demanded for point-of-care applications. In this work, the simultaneous detection of uric acid (UA), xanthine (XA), and hypoxanthine (HX) was carried out as model purine catabolites by surface-enhanced Raman Spectroscopy (SERS). The detection assay was conducted by employing high-aspect ratio Au nanopillar substrates coupled with in-situ Au electrodeposition on the substrates. The additional modification of the Au nanopillar substrates via electrodeposition was found to be an effective method to encapsulate molecules in solution into nanogaps of growing Au films that increase metal-molecule contact and improve substrate's sensitivity and selectivity. In complex solutions, the approach facilitated ternary identification of UA, XA, and HX down to concentration limits of 4.33 𝜇M, 0.71 𝜇M, and 0.22 𝜇M, respectively, which are comparable to their existing levels in normal human physiology. These results demonstrate that the proposed platform is reliable for practical point-of-care analysis of biofluids where solution matrix effects greatly reduce selectivity and sensitivity for rapid on-site disease diagnosis.

Effect of Nano-Bubble on Removal of Complex Heavy Metals (나노버블이 복합중금속(구리/납) 오염물 제거에 미치는 영향 분석)

  • Lee, Yang-Gyu;Han, Jung-Geun;Choi, Ju-Hyun;Kim, Dong-Chan;You, Seung-Kyong;Hong, Kikwon
    • Journal of the Korean Geosynthetics Society
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    • v.14 no.4
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    • pp.139-146
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    • 2015
  • This paper describes a effect of nano-bubble on removal of complex heavy metals, in order to remove pollutants of soil with copper (Cu) and lead (Pb) based on column test. It was conducted column test considering inflow and fine soil contents condition, and then it was analyzed removal effect of nano-bubble on Cu and Cu/Pb. The test result showed that the removal effect of the nano-bubble was higher than that of distilled water regardless of fine soil contents in case of Cu pollutant, and the removal effect of nano-bubble on heavy metals was found to have a significant impact on Pb than Cu in case of Cu/Pb pollutants. It was also analyzed that engineering properties (like a flow path and permeability) of soil due to void ratio has influenced a significant impact the pollutants removal of nano-bubble. The test results determined that nano-bubble can be applied as a flushing agent for priority target pollutant in complex heavy metals.

The Effect of Particle Size on Rheological Properties of Highly Concentrated Ag Nanosol (초 고농도 Ag 나노 졸의 입자크기 제어가 잉크 점성거동에 미치는 영향)

  • Song, Hae-Chon;Nham, Sahn;Lee, Byong-Seok;Choi, Young-Min;Ryu, Beyong-Hwan
    • Journal of the Korean Ceramic Society
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    • v.46 no.1
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    • pp.41-46
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    • 2009
  • The rheological properties of highly concentrated Ag nano sol depending on particle size were studied. The Ag nano sol was prepared by reducing the Ag ion in aqueous solution. The size of Ag nano particle was controlled by two steps of nucleation and growth, and the thickness of adsorption layer was varied by molecular weight of polyelectrolytes. The polyelectrolytes acted as not only ionic complex agent in ionic state and but also dispersant after formation of Ag nano sol. The effective volume was controlled by combination of varying the molecular weight of polyelectrolytes and the size Ag nano sol. The particle size and the viscosity of nano sol were characterized by particle size analyzer, HR-TEM and cone & plate viscometer. It was found that the 10 nm and 40 nm-sized Ag nano sols were prepared by controlling the nucleation and growth steps, respectively. Finally, we could prepare highly concentrated Ag nano sol over 50 wt%.

Characterization and Preparation of Low Molecular Weight Water Soluble Chitosan Nanoparticle Modified with Cell Targeting Ligand for Efficient Gene Delivery (효과적인 유전자전달을 위한 표적성 리간드가 도입된 저분자량 수용성 키토산 나노입자의 제조 및 특성)

  • Heo, Sun-Heang;Jang, Min-Ja;Kim, Dong-Gon;Jeong, Young-Il;Jang, Mi-Kyeong;Nah, Jae-Woon
    • Polymer(Korea)
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    • v.31 no.5
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    • pp.454-459
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    • 2007
  • Gene therapy using low molecular weight water soluble chitosan (LMWSC) as polycationic polymer shows good biocompatibility, but low transfection efficiency. The mechanism of folic acid (FA) uptake in the cells to promote targeting and internalization could improve transfection rates. The objective of this study was to synthesize and characterize the WSCFA-DNA complex and evaluate their cytotoxicity, in vitro. In $^1H-NMR$ spectra, specific peaks appeared both of FA and LMWSC in $D_2O$. WSCFA nanoparticles have spherical shapes with particle size show below 110 nm. In the cell cytotoxicity test, the WSCFA-DNA complex showed high cell viability, in vitro. Gel electrophoresis showed condensed DNA within the carriers. hi vitro transfection efficiency was assayed by fluorescence spectroscopy WSCFA nanoparticles have less cytotoxicity, good DNA condensation and particle size around 110 nm, which makes them a promising candidate as a non-viral gene vector.

Reduced graphene oxide field-effect transistor for biomolecule detection and study of sensing mechanism

  • Kim, D.J.;Sohn, I.Y.;Kim, D.I.;Yoon, O.J.;Yang, C.W.;Lee, N.E.;Park, J.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.431-431
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    • 2011
  • Graphene, two dimensional sheet of sp2-hybridized carbon, has attracted an enormous amount of interest due to excellent electrical, chemical and mechanical properties for the application of transparent conducting films, clean energy devices, field-effect transistors, optoelectronic devices and chemical sensors. Especially, graphene is promising candidate to detect the gas molecules and biomolecules due to the large specific surface area and signal-to-noise ratios. Despite of importance to the disease diagnosis, there are a few reports to demonstrate the graphene- and rGO-FET for biological sensors and the sensing mechanism are not fully understood. Here we describe scalable and facile fabrication of rGO-FET with the capability of label-free, ultrasensitive electrical detection of a cancer biomarker, prostate specific antigen/${\alpha}1$-antichymotrypsin (PSA-ACT) complex, in which the ultrathin rGO sensing channel was simply formed by a uniform self-assembly of two-dimensional rGO nanosheets on aminated pattern generated by inkjet printing. Sensing characteristics of rGO-FET immunosensor showed the highly precise, reliable, and linear shift in the Dirac point with the analyte concentration of PSA-ACT complex and extremely low detection limit as low as 1 fg/ml. We further analyzed the charge doping mechanism, which is the change in the charge carrier in the rGO channel varying by the concentration of biomolecules. Amenability of solution-based scalable fabrication and extremely high performance may enable rGO-FET device as a versatile multiplexed diagnostic biosensor for disease biomarkers.

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Synthesis of (Ni,Mg)Al2O4 Ceramic Nano Pigment by a Polymerized Complex Method (착체중합법을 이용한 (Ni,Mg)Al2O4 Cyan 나노 무기안료 합성)

  • Son, Bo-Ram;Yoon, Dea-Ho;Han, Kyu-Sung;Cho, Woo-Suk;Hwang, Kwang-Taek;Kim, Jin-Ho
    • Journal of the Korean Ceramic Society
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    • v.50 no.3
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    • pp.195-200
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    • 2013
  • Here, we report preparation of cyan ceramic nano-pigment for inkjet printing and the Ni substitutional effects on the cyan color. $MgAl_2O_4$ was selected as the crystalline host network for the synthesis of nickel-based cyan ceramic nano-pigments. Various compositions of $Ni_xMg_{1-x}Al_2O_4$ ($0{\leq}x{\leq}1$) powders were prepared using the polymerized complex method. The powder was then preheated at $400^{\circ}C$ for 5 h and finally calcined at $1000^{\circ}C$ for 5 h. XRD patterns of $Ni_xMg_{1-x}Al_2O_4$ showed a single phase of the spinel structure in all the compositions. The particle sizes ranged from 20 to 50 nm in TEM observations. The characteristics of the color tones of $Ni_xMg_{1-x}Al_2O_4$ were analyzed by UV-Visible spectroscopy and CIE $L^*a^*b^*$ measurement. CIE $L^*a^*b^*$ measurement results indicate that the pigment color changes from light cyan to deep cyan due to the decrease of the $a^*$ and $b^*$ values with an increase of an Ni substitutional amount. In addition, the thermal stability and the binding nature of $Ni_xMg_{1-x}Al_2O_4$ are also discussed using TG-DSC and FT-IR results respectively.

Synthesis and Supramolecular Assembly of Ru(II)-Terpyridine Complexes linked with β-Cyclodextrin or Adamantyl Group (β-CD 또는 아다만탄이 결합된 루테늄(II)-터피리딘 착화합물의 제조와 초분자 조립)

  • Park, Dae-Rim;Chung, Yong-Chae;Choi, Kyung-Ho;Kim, Hyung-Jin
    • Journal of the Korean Chemical Society
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    • v.51 no.6
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    • pp.526-535
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    • 2007
  • Ru(II)-terpyridine complexes (8, 9, 11) linked with adamantyl or β-cyclodextrin moieties were synthesized and characterized based on their 1H and 13C NMR spectra as well as MS spectra. Ru(II)-terpyridine complexes (8, 11) linked with adamantyl moiety were readily dissolved in aqueous solution via encapsulation by β-cyclodextrin when they were mixed with an equimolar amount of β-cyclodextrin. In the similar way, the adamantane guest of the Ru(II)-terpyridine complexes (8, 11) were encapsulated by β-cyclodextrin moiety of the ruthenium complex 9 to afford supramolecular assemblies in aqueous environment. Formation of assemblies was corroborated by 1H NMR spectroscopy.