• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.221-221
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• 2012

Small-molecule organic photovoltaic cells have recently attracted growing attention due to their potential for the low-cost fabrication of flexible and lightweight solar modules. The PVP/Ag nanoparticles were synthesized by the reaction of poly vinylpyrrolidone (PVP) and silver nitrate at $150^{\circ}C$. In the reaction, the size of the nanoparticles was controlled by relative mole fractions between PVP and Ag. The PVP/Ag nanoparticles with various sizes were then spin coated on the patterned ITO glass prior to the deposition of the PEDOT:PSS hole transport layer. The scattering of the incident light caused by these incorporated nanoparticles resulted in an increase in the path length of the light through the active layer and hence the enhancement of the light absorption. This scattering effect increased as the size of the nanoparticles increased, but it was offset by the decrease in total transmittance caused by the non-transparent nanoparticles. As a result, the maximum power conversion efficiency, 0.96% which was the value enhanced by 14% compared to the cell without incorporation of nanoparticles, was obtained when the mole fraction of PVP:Ag was 24:1 and the size of the nanoparticles was 20~40 nm.

• Korean Journal of Human Ecology
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• v.22 no.5
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• pp.461-476
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• 2013

This study aims to provide practical information of both color and hands of cotton fabrics dyed with persimmon dye powder for natural dyeing fashion industries by investigating dyeing behavior and color gamut, by testing mechanical properties depending on color characteristics, and finally by evaluating dyeing fastness. As results, the persimmon dye powder obtained by extracting the fruits to final solid powder was found as containing tannin and it partially coated between and on fibers similarly to traditionally dyed one. The K/S values of non-mordanted fabric and two differently mordanted ones with Fe and Cu seemed to reach their equilibrium from 800, 800, and 600% (owf), respectively. Yellow-red was the only one hue shown while tones were various as pale (p), light grayish (ltg), soft (sf), dull (d), grayish (g), and dark grayish (dkg). In mechanical properties, the dyed fabrics with p and ltg tended to be less altered than undyed ones whereas d and d kg by higher bath concentrations could be applied to boxy silhouette owing to their increased stiffness and less stretchability. Although fastness to dry cleaning and stain was good, color change by washing and rubbing needed to be improved.

• Korean Journal of Materials Research
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• v.27 no.8
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• pp.422-430
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• 2017

Al/expanded graphite was successfully synthesized through a facile method including ultrasonic and heat treatment. In the well-designed three dimensional structure, expanded graphite(EG) works as a conductive matrix to support coated Al particles. The effects of the fabrication parameters on the microstructures and thermal conductivities of these composites were investigated. As a result, it was found that composites with graphite volume fraction of 17.4-69.4 % sintered at $600^{\circ}C$/45MPa exhibit in-plane thermal conductivities of 380-940 W/mK, over 90 % of the predictions by rule of mixture. According to the non-destructive analysis results, the synergistic enhancement was caused by the formation of efficient thermally conductive pathways due to the hybrid of the differently sized EG. The structure integrates the advantages of expanded graphite as a conductive support, preserving the electrode activity and integrity and improving the electrochemical performance.

• Membrane and Water Treatment
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• v.11 no.3
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• pp.195-200
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• 2020

In this study, a biocatalyst composite was prepared by immobilizing oxidoreductases onto Cu-activated zeolite to facilitate biochemical decomposition of 4-chlorophenol (4-CP). 4-CP monooxygenase (CphC-I) was cloned from a 4-CP degrading bacterium, Pseudarthrobacter chlorophenolicus A6, and then overexpressed and purified. Type X zeolite was synthesized from non-magnetic coal fly ash using acetic acid treatment, and its surfaces were coated with copper ions via impregnation (Cu-zeolite). Then, the recombinant oxidative and reductive enzymes were immobilized onto Cu-zeolite. The enzymes were effectively immobilized onto the Cu-zeolite (79% of immobilization yield). The retained catalytic activity of CphC-I after immobilization was 0.3423 U/g-Cu-zeolite, which was 63.3% of the value of free enzymes. The results of this study suggest that copper can be used as an effective enzyme immobilization binder because it provides favorable metalhistidine binding between the enzyme and Cu-zeolite.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.111.1-111.1
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• 2015

As an alternative way to get sophisticated nanostructures, atomic force microscopy (AFM) has been used to directly manipulate building primitives. In particular, assembly of metallic nanoparticles(NPs) can provide various structures for making various metamolecules. As far, conventionally made polygonal shaped metallic NPs showed non-uniform distribution in size and shape which limit its study of fundamental properties and practical applications. In here, we optimized conditions for deterministic manipulation of ultra-smooth and super-spherical gold nanoparticles (AuNPs) by AFM. [1] Lowered adhesion force by using platinum-iridium coated AFM tips enabled us to push super-spherical AuNPs in linear motion to pre-programmed position. As a result, uniform and reliable electric/magnetic behaviors of assembled metamolecules were achieved which showed a good agreement with simulation data. Furthermore, visualization of near field for super-spherical AuNPs was also addressed using photosensitive azo-dye polymers. Since the photosensitive azo-dye polymers can directly record the intensity of electric field, optical near field can be mapped without complicated instrumental setup. [2] By controlling embedding depth of AuNPs, we studied electric field of AuNPs in different configuration.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.2 s.245
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• pp.153-160
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• 2006

A technique for measuring surface temperature field in micro scale is newly proposed, which uses temperature-sensitive fluorescent (TSF) dye coated on the surface and is easily implemented with a fluorescence microscope and a CCD camera. The TSF dye is chosen among mixtures of various chemical compositions including rhodamine B as the fluorescent dye to be most sensitive to temperature change. In order to examine the effectiveness of this temperature measurement technique, numerical analysis and experiment on transient conduction heat transfer for two different substrate materials, i. e., silicon and glass, are performed. In the experiment, to accurately measure the temperature with high resolution temperature calibration curves were obtained with very fine spatial units. The experimental results agree qualitatively well with the numerical data in the silicon and glass substrate cases so that the present temperature measurement method proves to be quite reliable. In addition, it is noteworthy that the glass substrate is more appropriate to be used as thermally-insulating locally-heating heater in micro thermal devices. This fact is identified in the temperature measuring experiment on the locally-heating heaters made on the wafer of silicon and glass substrates. Accordingly, this technique is capable of accurate and non-intrusive high-resolution measurement of temperature field in microscale.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.3
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• pp.144-151
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• 2009

Photocatalytic degradation of methylene blue (MB) in aqueous solution was investigated using $TiO_2$ coated on various acid modified activated carbon fiber (ACF). The ACFs/$TiO_2$ composites were prepared from titanium n-butoxide (TNB) as titanium precursor and various acid modified ACFs. The prepared samples are heat treated at 973 K. Then the ACF/$TiO_2$ composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX). Moreover, photocatalytic degradation of MB by the ACF/$TiO_2$ composites was determined under UV irradiation. The results shows that the photocatalytic activity of ACF/$TiO_2$ composites ($AT1{\sim}AT4$) prepared with TNB and various acid modified ACF was much better than that of ACF/$TiO_2$ composite (AT) prepared with TNB and non-acid modified ACF, and the effects improved with order of sample AT3 > AT4 > AT1 > AT2.

• The Journal of Internal Korean Medicine
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• v.26 no.4
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• pp.853-863
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• 2005

Object : This study was performed to investigate the anti-fibrogenic effect of Artemisiae Capillaris Herba(ACH) on cultured rat hepatic stellate cells. Methods : Hepatic Stellate Cells were obtained from a 350gm Sprague-Dawley rat by tissue perfusion system, and the cells for the study were selected after 3 passages of culture on non-coated plastic culture dishes which enable the cells to activate, thus producing collagens in the cell media. Cells were treated with various concentrations of Artemisia Capillaris Herba(ACH) extract powder for 24 or 48 hours. After the treatment, Soluble collagen, procollagen levels and the mRNA of the procollagen type I C were measured by using assay kit and RT-PCR method. Results : Procollagen production by the hepatic stellate cells decreased after the treatment in a time-dependent dose-dependent manner. The mRNA expression decreased consistently with the volume of the secreted procollagen which indicates the herb hat inhibitory effect on fibrogenesis of the liver by regulating one of the fibrosis associated genes in transcription. Conclusion : These results suggest that ACH is beneficial in the treatment of cirrhotic patients as well as for the patients with chronic hepatitis.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.325-328
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• 2001

Gelatin particle agglutination test (GPAT) was used to detect Cymbidum mosaic virus (CymMV) in Cattleya plants. Gelatin particles were coated with purified anti-CymMV immunoglobulin of 25-100 $\mu\textrm{g}$/ml and were subjected to several different concentrations of purified CyMfV as well as varying dilutions of orchid leaf extracts. The GPAT detected purified CymMV up to a minimum concentration of 10 $\mu\textrm{g}$/ml. CymMV was detected from crude sap extract of infected Cattleya leaves and roots up to 1:51,200 and 1:25,600 dilutions, respectively. However, the optimum range of leaf and root sap dilutions was between 50-100. Non-specific reactions were not encountered from any of the healthy orchid plants tested. The entire GPAT process was completed within 2-3 hours. This test was found to be very useful for the detection of CymMV in orchids because it is sensitive, economical, and easy to perform.

• Macromolecular Research
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• v.17 no.4
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• pp.259-264
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• 2009

Chemical modification of magnetic nanoparticles(MNPs) with functional polymers has recently gained a great deal of attention because of the potential application of MNPs to in vivo and in vitro biotechnology. The potential use of MNPs as capturing agents and sensitive biosensors has been intensively investigated because MNPs exhibit good separation-capability and binding-specificity for biomolecules after suitable surface functionalization processes. In this work, we demonstrate an efficient method for the surface modification of MNPs, by combining surface-initiated polymerization and the subsequent conjugation of the biologically active molecules. The polymeric shells of non-biofouling poly(poly(ethylene glycol) methacrylate)(pPEGMA) were introduced onto the surface of MNPs by surface-initiated, atom transfer radical polymerization(SI-ATRP). With biotin as a model of biologically active compounds, the polymeric shells underwent successful post-functionalization via activation of the polymeric shells and bioconjugation of biotin. The resulting MNP hybrids showed a biospecific binding property for streptavidin and could be separated by magnet capture.