• Journal of radiological science and technology
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• v.45 no.3
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• pp.225-232
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• 2022

Fine dust threatens human health in various forms, depending on the particle size, such as by causing respiratory, cardiovascular, and brain diseases, after entering the body via the lungs. The aim of this study was to correlate fine dust exposure with changes in brain blood flow in Sprague Dawley rats by using micro-positron emission tomography and elucidate the possibility of developing cerebrovascular diseases caused by fine dust. The subjects were exposured to an average fine dust (particulate matter 2.5) of 206.2 ± 7.74 to ten rats four times a day, twice a day for 90 min. Before the experiment, they were maintained at NPO to the maximize the intake of ¹⁸F-fluorodeoxy glucose(¹⁸F-FDG) and minimize changes in the ¹⁸F-FDG biomass depending on the ambient environment and body temperature of the rats. PET images were acquired in the list mode 40 min after injecting ¹⁸F-FDG 44.4 MBq into the rats tail vein using a micro-PET scanner pre and post exposure to fine dust. We found that the whole brain level of ¹⁸F-FDG standardized uptake value in rats averaged 5.21 ± 0.52 g/mL pre and 4.22 ± 0.48 g/mL post exposure to fine dust, resulting in a statistically significant difference. Fine dust was able to alter brain activity after entering the body via the lungs in various forms depending on the particle size.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.485-489
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• 2017

Polyethylene terephthalate (PET) has been widely applied in polymers and packaging industries to produce synthetic fibers, films, drink bottles or food containers. Therefore, it has become one of the major plastic wastes. In this article, glycolysis known as one of the main methods in PET chemical recycling was investigated using a glycol to break down the polymer into a monomer. Glycolysis of PET and ethylene glycol was performed in a micro-tubing reactor under various conditions. The effect of glycolysis conditions on the product distribution was investigated at experimental conditions of the EG/PET ratio of 1~4, the reaction time of 15~90 min and the reaction temperature of $250{\sim}325^{\circ}C$ with Mn and Cu catalysts. The highest yield of bis (2-hydroxyethyl) terephthalate monomer (BHET) was obtained as 89.46 wt% under the condition of the reaction temperature of $300^{\circ}C$ and the time of 30 min using 10 wt% $Cu/{\gamma}-Al_2O_3$ catalyst, with the PET and ethylene glycol ratio of 1 : 2.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.376-376
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• 2002

편평분할사는 복합방사법에 의한 편평 단면 형태의 분할형 초극세섬유로서, 기존 오렌지 형태인 Nylon/PET 극세사의 품종 다양화된 형태이다 분할은 Nylon과 PET의 비상용성인 특징을 이용, 물리적인 가공과 화학적인 가공에 의해 이루어지며 기존오렌지 형태의 PET/Nylon극세사에 비해 분할성이 우수하다고 보고되고 있다. 편평분할사의 용도는 Micro powder조의 Suede직물 등의 여성용 의류, 기능성 스포츠웨어, 2차 오염방지성이 우수하여 반도체 등의 정밀산업의 닦음천(Wiping Cloth)등의 크리너(Cleaner)용으로도 사용되어 질 수 있다. (중략)

• Journal of Fashion Business
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• v.13 no.1
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• pp.82-90
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• 2009

This research was made to manufacture the fabric for interior uses by spinning a low melting mono 4 denier PET staple fiber with a soluble 1.4 denier fine PET fiber. The blended yarn has a thickness ranging from 10's to 14's, and the soluble PET fine fiber was dissolved to make a pore in the polymer. Thereby a snap property was decreased and a resilience property was improved to be suitable for a functional synthetic leather. In order to attain the optimum condition, a mechanical property according to fineness, and mixing ratio of low melting polymer, warp density, weft density and blending ratio, and a heat contraction ratio according to blending ratio were experimented. The warp density, 220 T/inch of fine denier PET and the weft density, 64 T/inch of thick denier PET were generated to 4/4 both twill weave fabric having constant tensile property and thickness.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.401-409
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• 2008

Purpose: Recently multi-modal imaging system has become widely adopted in molecular imaging. We tried to fabricate animal-specific positioning molds for PET/MR fusion imaging using easily available molding clay and rapid foam. The animal-specific positioning molds provide immobilization and reproducible positioning of small animal. Herein, we have compared fiber-based molding clay with rapid foam in fabricating the molds of experimental animal. Materials and Methods: The round bottomed-acrylic frame, which fitted into microPET gantry, was prepared at first. The experimental mice was anesthetized and placed on the mold for positioning. Rapid foam and fiber-based clay were used to fabricate the mold. In case of both rapid foam and the clay, the experimental animal needs to be pushed down smoothly into the mold for positioning. However, after the mouse was removed, the fabricated clay needed to be dried completely at $60^{\circ}C$ in oven overnight for hardening. Four sealed pipet tips containing $[^{18}F]FDG$ solution were used as fiduciary markers. After injection of $[^{18}F]FDG$ via tail vein, microPET scanning was performed. Successively, MRI scanning was followed in the same animal. Results: Animal-specific positioning molds were fabricated using rapid foam and fiber-based molding clay for multimodality imaging. Functional and anatomical images were obtained with microPET and MRI, respectively. The fused PET/MR images were obtained using freely available AMIDE program. Conclusion: Animal-specific molds were successfully prepared using easily available rapid foam, molding clay and disposable pipet tips. Thanks to animal-specific molds, fusion images of PET and MR were co-registered with negligible misalignment.

• Journal of Convergence for Information Technology
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• v.7 no.1
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• pp.43-48
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• 2017

The design trend is changed with the times. The design trend of recent 21 century is eco-friendly design. The optical illusion design is a new trend of digital convergence era. In this study, optical illusion patterns were designed for furniture with eco-friendly UV-curable resin. The micro-patterns of optical illusion design were fabricated with the micro-mold which was mastered using a semiconductor micro-fabrication process by photolithography technique. The micro-patterns of optical illusion design were manufactured on PET film with a roll-to-roll process using a UV-curable resin. The manufactured PET film of optical illusion micro-pattern exhibits hologram effect, optical illusion effect, and texture of metal with the backside digital printing of metal tone. The furniture of new design concept so-called emotional furniture was manufactured with the various optical illusion design patterns. The optical illusion design patterns by UV mold prospect a new trend of interior design materials.

• Toxicological Research
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• v.29 no.1
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• pp.1-6
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• 2013

The process of drug discovery and development requires substantial resources and time. The drug industry has tried to reduce costs by conducting appropriate animal studies together with molecular biological and genetic analyses. Basic science research has been limited to in vitro studies of cellular processes and ex vivo tissue examination using suitable animal models of disease. However, in the past two decades new technologies have been developed that permit the imaging of live animals using radiotracer emission, X-rays, magnetic resonance signals, fluorescence, and bioluminescence. The main objective of this review is to provide an overview of small animal molecular imaging, with a focus on nuclear imaging (single photon emission computed tomography and positron emission tomography). These technologies permit visualization of toxicodynamics as well as toxicity to specific organs by directly monitoring drug accumulation and assessing physiological and/or molecular alterations. Nuclear imaging technology has great potential for improving the efficiency of the drug development process.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.12
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• pp.13-20
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• 2004

Manufacturing process for the microfluidic device can include such sequential steps as master fabrication, electroforming, and injection molding. The laser ablation using masks has been applied to the fabrication of channels in microfluidic devices. In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation of PET (polyethylene terephthalate) by the excimer laser radiation could be used successfully to make three dimensional master fur nickel mold insert. The mechanism fur ablative decomposition of PET with KrF excimer laser $({\lambda}: 248 nm, pulse duration: 5 ns)$ was explained by photochemical process, while ablation mechanism of PMMA (polymethyl methacrylate) is dominated by photothermal process, the .eaction between PC (polycarbonate) and KrF excimer laser beam generate too much su.face debris. Thus, PET was adopted in polymer master for nickel mold insert. Nickel electroforming using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

• Journal of the Korean Home Economics Association
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• v.36 no.8
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• pp.95-104
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• 1998

PET microfiber fabric dissociation reactions by ethylene glycol (EG) catalayzed by the corresponding EG anions were examined to provide an empirical basis for the improvement of a PET microfiber fabrics. The alkoxide ions, monosodium ethylene glycolate in ethylene glycol solution(MSEG-EG) are prepared by the reaction between NaH and the EG respectively. The dissociation reactions were carried out until the sample PET microfiber fabrics dissociate up to 80%. Temperature used ranged 100~$160^{\circ}C$. The kinetic behaviors of the dissociated PET microfiber fabrics were examined. The results are as follows : 1. In all cases, it was found that the PET-alkoxide dissociation rate constants increased exponentially with increasing temperature. The activation energies (Ea) of the reactions were 23.31kcal/mol in PET-EG system respectively. The calculated enthalpies of the activated [PET-EG] complexes from the corresponding Ea values were 22.53 ~ 22.61 kcal/mol, and the entropies were -19.03 ~ -19.24 kcal/mol/k respectively. 2. The kinetic behavior of the PET-alkoxide dissociation reactions examined was explained by the transition state theory. PET-alkoxide transition state is believed to be formed during the ester interchange mechanism between PET and MSEG-EG in the course of the PET dissociation reactions.

• The Journal of the Korea Contents Association
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• v.9 no.11
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• pp.262-270
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• 2009

$^{18}F$-mefway has been developed as radioligand for serotonin receptor 5-$HT_{1A}$. The object of this study was to obtain the mefway precursor with the higher yield than previous method and to identify whether $^{18}F$-mefway can bind to 5-$HT_{1A}$ or not. from microPET imaging of small animal brain. Precursor was prepared by a modification of the reported procedure then [$^{18}F$] labeling was performed by adding $^{18}F$ ion at $130^{\circ}C$ in the hot cell for 30min. After purification of reaction mixture using alumina Sep-pak and HPLC, microPET images of small animal brain were determined. The chemical yield of precursor was increased from 9% to 34% using oxalyl chloride and LAH/diethylether. We synthesized a precursor which was successfully labeled with no-carrier-added $^{18}F$-by new synthetic route. This research suggest that $^{18}F$-mefway will be used a radiopharmaceutical for evaluation of central nerve system disorder as imaging a gent for 5-$HT_{1A}$ receptor.