• Journal of the Korean Applied Science and Technology
• /
• v.31 no.4
• /
• pp.694-702
• /
• 2014

The micron-sized ITO(indium tin oxide) particles were prepared by spray pyrolysis from aqueous precursor solutions for indium, and tin and organic additives solution. Organic additives solution with citric acid(CA) and ethylene glycol(EG) were added to aqueous precursor solution for Indium and Tin. The obtained ITO particles prepared by spray pyrolysis from the aqueous solution without organic additives solution had spherical and filled morphologies whereas the obtained ITO particles with organic additives solution had more hollow and porous morphologies with increasing mole of organic additives. The micron-sized ITO particle with organic additives was changed fully to nano-sized ITO particle whereas the micron-sized ITO particle without organic additives was not changed fully to nano-sized ITO particle after post-treatment at $700^{\circ}C$ for 2 hours and wet-ball milling for 24 hours. The size of primary ITO particle by Debye-Scherrer formula and surface resistance of ITO pellet were measured.

• Proceedings of the Korean Society of Dyers and Finishers Conference
• /
• 2008.04a
• /
• pp.28-30
• /
• 2008

Poly(ethylene oxide)(PEO) of molecular weight of 300,000 was crosslinked by exposure to UV irradiation. Photochemical crosslinking of PEO occurred by UV irradiation and the presence of benzophenone in the film which acts as a hydrogen-abstracting agent. Percent conversion of the polymer into gel as well as water absorbency were investigated gravimetrically. Gel fraction and water absorbency of PEO films increased with increasing UV energy. In case of photocrosslinked PEO films with benzophenone, gel fraction increased up to about 90%. The thermal behavior of crosslinked PEO films was studied by thermogravimetric analysis. The maximum decomposition temperature increased with increasing UV energy and benzophenone concentration.

• Journal of Powder Materials
• /
• v.25 no.3
• /
• pp.203-207
• /
• 2018

Plastic pollution is threatening human health and ecosystems, resulting in one of the biggest challenges that humanity has ever faced. Therefore, this study focuses on the preparation of macroporous carbon from biowaste (MC)-supported manganese oxide ($MnO_2$) as an efficient, reusable, and robust catalyst for the recycling of poly(ethylene terephthalate) (PET) waste. As-prepared $MnO_2/MC$ composites have a hierarchical pore network and a large surface area ($376.16m^2/g$) with a narrow size distribution. $MnO_2/MC$ shows a maximum yield (98%) of bis(2-hydroxyethyl)terephthalate (BHET) after glycolysis reaction for 120 min. Furthermore, $MnO_2/MC$ can be reused at least nine times with a negligible decrease in BHET yield. Based on this remarkable catalytic performance, we expect that $MnO_2$-based heterogeneous catalysts have the potential to be introduced into the PET recycling industry.

• Toxicological Research
• /
• v.6 no.1
• /
• pp.63-73
• /
• 1990

Human exposure to environmental carcinogens can be detected by a number of methods including immunoassay, $^{32}P-postlabeling$ assay, and fluorescence technique. These assays have been applied to measure biological markers of carcinogen-adducts formed with macromolecules such as DNA, RNA and protein. In an attempt to investigate causal relationships between carcinogen exposure and tumor formation, specific carcinogen-adducts have been quantitated from human tissues and body fluids of cancer patients, occupational workers heavily exposed to certain carcinogens, smokers and controls. Carcinogens studied for biological human monitoring include benzo(a)pyrene, aflatoxin B1, UV light, ethylene oxide, 8-methoxypsoralen, 4-aminobiphenyl, vinyl choride, N-nitrosamine, cisplatin and other chemotherapeutic agents. Relevance of human monitoring for cancer research, progress in this field, methods to detect carcinogen-adducts are reviewed here. It is hoped that these approaches will be used for the risk assessment of carcinogen exposure, cancer etiology study and cancer prevention in humans.

• Toxicological Research
• /
• v.6 no.1
• /
• pp.61-61
• /
• 1990

Human exposure to environmental carcinogens can be detected by a number of methods including immunoassay, $^{32}P$-postlabeling assay, and fluorescence technique. These assays have been applied to measure biological markers of carcinogen-adducts formed with macromolecules such as DNA, RNA and protein. In an attempt to investigate causal relation ships between carcinogen exposure and tumor formation, specific carcinogen-adducts have been quantitated from human tissues and body fluids of cancer patients, occupational workers heavily exposed to certain carcinogens, smokers and controls. Carcinogens studied for biological human monitoring include benzo(a)pyrene, aflatoxin B1, UV light, ethylene oxide, 8-methoxypsoralen, 4-aminobiphenyl, vinyl chloride, N-nitrosamine, cisplatin and other chemotherapeutic agents. Relevance of human monitoring for cancer research, progress in this field, methods to detect carcinogen-adducts are reviewed here. It is hoped that these approaches will be used for the risk assessment of carcinogen exposure, cancer etiology study and cancer prevention in humans.

• Journal of Pharmaceutical Investigation
• /
• v.33 no.3
• /
• pp.163-169
• /
• 2003

In order to develop a film-forming transdermal drug delivery system, polyurethane (PU) based on poly(ethylene glycol) and poly(tetramethylene oxide) was synthesized and characterized. The synthesized PU was blended with Gantrez ES 225 (GT) to improve the adhesion property of film-forming agent to the skin. When film-forming gel formulation containing 3% ketoprofen (KP) was applied, transparent thin film was obtained within 5 minutes and adhered to the skin for 8 hours. In vitro percutaneous absortion studies were performed to determine the rate of ketoprofen absorption through guinea pig skin. A prominent effect of limonene on the skin permeability of ketoprofen was observed among the various skin permeation enhancers investigated. Considering mechanica properties of film and skin permeability of ketoprofen, 2% of limonene was optimal content in the film forming transdermal formulation.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.190-190
• /
• 2003

여러원소 (Sb, F 등)를 도핑한 SnO$_2$ 투명전도막은 여러 가지 훌륭한 특성으로 Solar cell, heat mirrors, gas sensors, liquid crystal displays, thick film resistor 등과 같이 넓은 범위에서 응용되고 있다. 본 연구에서는 Sb 도핑된 Tin Oxide films이 Sol-gel dip coating법에 의해 준비되었다. SnO$_2$:Sb 용액은 SnC1$_2$ 와 SbC1$_3$ Power를 알코올에 용해하여 Ethylene glycol 와 Citric acid를 첨가하여 합성하였다. 막의 상형성은 XRD와 SEM(Scanning electron microscope)에 의해서 분석되었으며, 특성분석은 투과율(UV/VIS Spectrophotometer)과 표면전기저항(four point probe)으로 분석되었다. SiO$_2$ barrier이 SnO$_2$:Sb 막의 특성에 미치는 영향을 확인하기 위하여 XPS(X-ray photoelectron spectroscopy) 분석이 적용되었다.

• Journal of the Korean Applied Science and Technology
• /
• v.11 no.1
• /
• pp.61-70
• /
• 1994

New anionic oligomeric surfactants, sodium bis(alkyl decaoxyethylene) sulfonated succinates, had been synthesized through the addition reaction of sodium hydrogen sulfite to bis(alkyl decaoxyethylene) maleates. Bis(alkyl decaoxyethylene) maleates were obtained by esterification with maleic anhydride and long chain alkyl decaoxyethylene ethers which were also obtained by addition ethylene oxide 10 mole to straight long chain alcohol with alkyl group having from 10 to 18 carbon atoms, their structure of the synthetic compounds have been characterized with IR. $^{1}H$ NMR and elemental analysis respectively.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.295-295
• /
• 2006

In present study, poly(acrylic acid) (PAA) and hydrophobically modified poly(ethylene oxide) (HM-PEO) multilayers based on the hydrogen bonding between the component polymer pair have been prepared by the LbL deposition method. Dip assembled HM-PEO/PAA multilayers yield unique film morphologies in comparison with PEO/PAA multilayers due to the micellar formation of HM-PEO owing to the hydrophobic attraction between alkyl chains end-capped with the PEO chains. Individual HM-PEO micelles were connected through the bridging PEO chains to form temporary networks on multilayer surface and induced peculiar surface morphology on HM-PEO/PAA multilayers above the critical number of bilayers.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.249-249
• /
• 2006

We have prepared an amphiphilic wedge-coil molecule consisting of a hydrophobic wedge-like segment and a hydrophilic poly(ethylene oxide) (PEO) segment. The wedge-coil block molecule self-assembles into cylindrical nanofibers in both polar as well as nonpolar solvents. Remarkably, the resulting nanofibers, as solvent polarity change from water to n-hexane, change from highly flexible coil-like to stiff rod-like characteristics. This dynamic switching in the stiffness of the nanofibers in response to solvent polarity is attributed to the structural inversion of cylindrical core from bulky dendritic segments with amorphous nature to crystallizable linear PEO segments.