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2-Thienyl chalcone 유도체에 대한 Thioglycolic acid의 친핵성 첨가반응 연구
공승대,황성규,이기창,최상회,오세영 明知大學校 産業技術硏究所 1994 産業技術硏究所論文集 Vol.13 No.-
The Addition reaction kinetics of 2-Thienyl chalone derivatives[][] was investigated by ultraviolet spectrophotometery in 20% dioxane-H2O at 25. The structure of these compounds were ascertained by means of ultraviolet, melting point,IR and NMR spectra. The final product was 2-thienyl chalcone-thioglycolic acid synthesized by the addition of thioglycolic acid for the 2-thienyl chalcone. The rate equations which were applied over a wide pH range(pH 1.013.0) were obtained. The substituent effects on 2-thienyl chalcone derivatives[][] were studied, and the addition reaction were facilitated by electron attracting groups. On the basis of the rate equation and substitutent effect and general base effect,the plausible addition reaction mechanism was proposed : Below pH 9.0, neutral H2O molecule and thioglycolic acid anion competitively attacked on the double bond. Above pH 9.0, It was proportional to concentration of hydroxideion.
Sulfa 제의 Dual Action에 의한 지속성과 항균성
공승대(Seung Dae Kong),황성규(Sung Kwy Hwang),윤철훈(Cheol Hun Yoon),김진영(Jin Yeong Kim),이한섭(Han Seob Lee) 한국유화학회 2000 한국응용과학기술학회지 Vol.17 No.4
N/A Dual-actions are the most recently used delivery system in drug study. Dual-action agents are unique chemical entities comprised of two different type of antibacterial compounds covalently linked together in a single molecule in such a way that both components are able to exert their bactericidal properties. Crosslinked sulfadiazine-sulfanilamide such as antibiotics is synthesized by synthetic handle with glutaraldehyde. As a result, New synthetic antibacterial agent exhibited the broad antibacterial activities against gram(+) and gram(-) of 4 strains and a long durability supposing that the stomach and blood.
천연고분자 기재에 의한 수용성 항고지단백혈증제의 흰쥐 피부투과 특성
공승대(Seung Dae Kong),황성규(Sung Kwy Hwang),정덕채(Duck Chae Jung) 한국유화학회 2000 한국응용과학기술학회지 Vol.17 No.2
Transdermal therapeutic system(TTS) is often used as the method of drug dosage into the epidermic skin. Natural polymer were selected as ointment material of TTS. We investigated the permeation of natural polymer ointment containing drug in rat skin using horizontal membrane cell model. Permeation properties of materials were investigated for water-soluble drug such as oxiniacic acid in vitro. These results showed that skin permeation rate of drug across the composite was mainly dependent on the property of ointment base and drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate. This result suggests a possible use of natural polymer ointment base as TTS of antihyperlipoproteinemic agent.
The role of mass transfer layer on the tribological characteristics of silver-coated surfaces
Seung Ho Yang,Hosung Kong,Eui-Sung Yoon,Dae Eun Kim 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.2002 No.10
Wear map of silver coatings on AISI 52100 has been constructed to delineate the wear transition behavior with the change in operating conditions in various environments. Three main regimes were clearly identified: (ⅰ) elastic/plastic deformation of silver coating without failure, (ⅱ) mild wear regime after initial failure of silver coating and (ⅲ) severe wear regime. In the mild wear regime, the contact surfaces were covered with transfer layers of agglomerated wear particles. The transfer layer acted as a protective layer and resulted in low friction even after the initial failure of the coated films, whose characteristics were strongly dependent on both the operating and environmental conditions. Also, the existence of the critical sliding speed, above which no transfer layer was able to form, was discussed in the work.
Three‑phase 11 kW on‑board charger with single‑phase reverse function
Seung-Hwan Mun,Seung-Won Choi,Dae-Young Hong,So-Jeong Kong,Jun-Young Lee 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.8
This paper presents an 11 kW bidirectional on-board charger (OBC) design method with a single-phase discharge mode. The proposed OBC comprises an inverter, bidirectional LLC resonant converter, and buck converter. Different from the conventional bidirectional CLLLC resonant converter, power is controlled using a buck converter during reverse operation; therefore, considering the reverse gain when designing the LLC resonant converter is unnecessary. In addition, because the proposed method is designed by optimizing the forward direction, it can freely select a switching frequency, and the size of the magnetic components can be reduced, improving the power density. The validity of the proposed circuit is verified via a prototype OBC, with a grid voltage of 3 phase 380 VAC and a battery voltage of 270–464 V.
Yang, Seung Bo,Kong, Byung-Seon,Jung, Dae-Hwan,Baek, Youn-Kyoung,Han, Chang-Soo,Oh, Sang-Keun,Jung, Hee-Tae Royal Society of Chemistry 2011 Nanoscale Vol.3 No.4
<P>The use of carbon nanotubes (CNTs) as transparent conducting films is one of the most promising aspects of CNT-based applications due to their high electrical conductivity, transparency, and flexibility. However, despite many efforts in this field, the conductivity of carbon nanotube network films at high transmittance is still not sufficient to replace the present electrodes, indium tin oxide (ITO), due to the contact resistances and semi-conducting nanotubes of the nanotube network films. Many studies have attempted to overcome such problems by the chemical doping and hybridization of conducting guest components by various methods, including acid treatment, deposition of metal nanoparticles, and the creation of a composite of conducting polymers. This review focuses on recent advances in surface-modified carbon nanotube networks for transparent conducting film applications. Fabrication methods will be described, and the stability of carbon nanotube network films prepared by various methods will be demonstrated.</P> <P>Graphic Abstract</P><P>This review focuses on recent advances in surface-modified carbon nanotube networks for transparent conducting film applications. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0nr00855a'> </P>