• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.467-468
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• 2006

In this work, we present the comparison between $d_{31}\;and\;d_{33}$ mode characterization using the PZT micro-actuator for large displacement. The PZT micro-actuator consisted of Si, PZT, and Pt layer on SOI wafer. The electrode shapes were laminated and interdigitated for $d_{31}\;and\;d_{33}$ mode, respectively. In order to characterize the actuation mode, we measured the displacement using laser interferometer. The maximum displacement of d31 mode was $12.2{\mu}m$ at 10V, the actuation characterization of d31 was better than that of d33 mode. We estimated that displacement of d33 mode would be larger than that of d31 above 30V.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.222-226
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• 2016

The synthesis of pure calcium carbonate nanocrystals was achieved using a simultaneous injection method to produce nano particles of uniform size. These were characterized using scanning electron microscopy and powder X-ray diffraction. The nano particles were needle-shaped aragonite polymorphs, approximately 100-200 nm in length. The aragonite polymorph of calcium carbonate was prepared using aqueous solutions of $CaCl_2$ and $Na_2CO_3$, which were injected simultaneously into double distilled water at $50^{\circ}C$ and then allowed to react for 1.5 h. The resulting whisker-type nano aragonite with high aspect ratio (30) is biocompatible and potentially suitable for applications in light weight plastics, as well as in the medical, pharmaceutical, cosmetic and paint industries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.110-114
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• 2021

In this study, we fabricated light-weight solar module for various applications such as building integrated photovoltaics (BIPV), vehicles, trains, etc. Ethylene tetra fluoro ethylene (ETFE) film was applied as a material to replace the cover glass, which occupies more than 65% of the weight of the PV module. Glass fiber reinforced plastic (GRP) was applied to the ones with a low durability by replacing the cover glass to ETFE. Moreover, to achieve a high solar power conversion in this study, we applied a shingled design to weight reduced solar modules. The shingled module with GRP shows 183.7 W of solar-to-power conversion, and the output reduction rate after weight load test was 1.14%.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.154.2-154.2
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• 2007

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.173-173
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• 2006

We have explored a strategy to control the supramolecular nano-structures self-assembled from rigid segments through attachment of flexible chains through microphase separation and anisotropic arrangement. Supramolecular structures formed by self-assembly of rigid building blocks can be precisely controlled from 1-D layered, 3-D bicontinuous cubic to 2-D cylindrical structures by systematic variation of the type and relative length of the respective blocks. Furthermore, depending on the individual molecular architectures, rigid building blocks self-assemble into a wide range of supramolecular structures such as honeycomb, disk, cylinder, helix, tube, barrel stave, and nano-cage.

• Journal of Veterinary Science
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• v.24 no.1
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• pp.3.1-3.13
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• 2023

Background: Zinc (Zn) is an essential cofactor for physiological homeostasis in the body. Zn oxide (ZnO), an inorganic compound that supplies Zn, exists in various sizes, and its bioavailability may vary depending on the size in vivo. However, comparative studies on the nutritional effects of micro-sized ZnO (M-ZnO) and nano-sized ZnO (N-ZnO) supplementation on Zn deficiency (ZnD) animal models have not been reported. Objectives: This study investigated the nutritional bioavailability of N-ZnO and M-ZnO particles in dietary-induced ZnD mice. Methods: Animals were divided into six experimental groups: normal group, ZnD control group, and four ZnO treatment groups (Nano-Low, Nano-High, Micro-Low, and MicroHigh). After ZnD induction, N-ZnO or M-ZnO was administered orally every day for 4 weeks. Results: ZnD-associated clinical signs almost disappeared 7 days after N-ZnO or M-ZnO administration. Serum Zn concentrations were higher in the Nano-High group than in the ZnD and M-ZnO groups on day 7 of ZnO treatment. In the liver and testis, Nano-Low and Nano-High groups showed significantly higher Zn concentrations than the other groups after 14-day treatment. ZnO supplementation increased Mt-1 mRNA expression in the liver and testis and Mt-2 mRNA expression in the liver. Based on hematoxylin-and-eosin staining results, N-ZnO supplementation alleviated histological damage induced by ZnD in the testis and liver. Conclusions: This study suggested that N-ZnO can be utilized faster than M-ZnO for nutritional restoration at the early stage of ZnD condition and presented Mt-1 as an indicator of Zn status in the serum, liver, and testis.

• Journal of the Korean Vacuum Society
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• v.17 no.1
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• pp.67-72
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• 2008

We have studied the effect of heat treatment of multi-walled carbon nanotubes (MWNTs) as a counter electrode on the electro-chemical properties of dye-snsitized solar cells. MWNTs on the p-type Si substrate were synthesized by thermal chemical vapor deposition (CVD) using Fe catalysts. We prepared the two types of MWNTs samples with the different diameters. The rapid thermal annealing (RTA) treatment for the MWNTs was carried out at the growth temperature ($900^{\circ}C$) for 1 minute with $N_2$ gas atmosphere. The structural, electrical and electrochemical properties of MWNTs were investigated by field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, 2-point probe station and electrochemical impedance spectroscopy (EIS). The I(D)/I(G) ratio of heat-treated MWNTs in Raman spectra was considerably decreased. It was also found that the heat-treated MWNTs showed better redox reaction of iodide at the interface between MWNTs surface and electrolyte than that of as-grown MWNTs. The redox resistance value of heat-treated electrodes was measured to be much lower than that of as-grown electrode at the interface. As a result, the counter electrode using the heat-treated MWNTs showed better electrochemical properties.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.3
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• pp.158-163
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• 2005

The purpose of this study was to observe the effect on the marine environment by the use of Nano-S. Nano-S was made to apply to improve the red tide bloom. The experiment was performed at round tank with volume of 180 L. Each tank was filled with an aggravated sediment about $14{\pm}1cm$ hight and sea water. The water flow-rate of tank was established on the rate of 6.25 L/hr. Sea water level was fitted to 40 cm, therefore the filled water was about 150 L. The sediment was stabilized during one week. Then the Nano-S and the red mud were added into each tank 0 kg(control), 1 kg(tank A), 2 kg(tank B), 5 kg(tank C) and 10 kg(tank D) each other. The quantity was fulfilled with 0 kg(control), 2.75 kg(tank A), 5.51 kg(tank B), 13.77 kg(tank C) and 27.55 kg(tank D) per square meter of sediment. The experiment was performed during 30 days. Water and sediment samples were collected from each tanks on the before 1hour and after 1, 3, 6, 12 hour and 1st, 3th, 5th, 7th, 10th, 15th, 30th day of the experiment period. The change of water and sediment quality was analyzed before and after applying the Nano-S and the red mud.

• Journal of Microbiology and Biotechnology
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• v.27 no.4
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• pp.808-815
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• 2017

We demonstrated the quantitative detection of a toxin-producing Microcystis aeruginosa (M. aeruginosa) strain with the laboratory protocol of the NanoGene assay. The NanoGene assay was selected because its laboratory protocol is in the process of being transplanted into a portable system. The mcyD gene of M. aeruginosa was targeted and, as expected, its corresponding fluorescence signal was linearly proportional to the mcyD gene copy number. The sensitivity of the NanoGene assay for this purpose was validated using both dsDNA mcyD gene amplicons and genomic DNAs (gDNA). The limit of detection was determined to be 38 mcyD gene copies per reaction and 9 algal cells/ml water. The specificity of the assay was also demonstrated by the addition of gDNA extracted from environmental algae into the hybridization reaction. Detection of M. aeruginosa was performed in the environmental samples with environmentally relevant sensitivity (${\sim}10^5$ algal cells/ml) and specificity. As expected, M. aeruginosa were not detected in nonspecific environmental algal gDNA over the range of $2{\times}10^0$ to $2{\times}10^7$ algal cells/ml.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.3
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• pp.187-192
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• 2017

This paper presents an ongoing study to develop a novel pressure sensor by means of a Nano Carbon Piezoresistive Composite (NCPC). The sensor was fabricated using the 3D printing process. We designed a miniaturized cantilever-type sensor electrode to improve the pressure sensing performance and utilized a 3D printer to build a small-sized body. The sensor electrode was made of 2 wt％ MWCNT/epoxy piezoresistive nano-composite, and the sensor body was encapsulated with a pipe plug cap for easy installation to any pressure system. The piezoresistivity responses of the sensor were converted into stable voltage outputs by using a signal processing system, which is similar to a conventional foil strain gauge. We evaluated the pressure-sensing performances using a pressure calibrator in the lab environment. The 3D-printed cantilever electrode pressure sensor showed linear voltage outputs of up to 16,500 KPa, which is a 200％ improvement in the pressure sensing range when compared with the bulk-type electrode used in our previous work.