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PP/MMT 나노복합재료의 열안정성 및 기계적 계면 특성에 관한 연구
박수진,전병렬,송시용,이종문 한국공업화학회 2004 공업화학 Vol.15 No.1
본 연구에서는 몬모릴로나이트(Na^(-)-montmorillonite, MMT)를 dodecylammonium chloide로 유기적 개질하여 폴리프로필렌(PP) 나노복합재료의 열안정성과 기계적 계면 물성에 미치는 영향을 조사하였다. 나노복합재료의 구조 및 표면 특성은 각각 XRD와 FT-IR을 통해 알아보았고, 열안정성은 TGA를 통해 알아보았으며, 주조된 시편의 기계적 계면 물성은 K_(IC)와 G_(IC)를 통해 알아보았다. 실험 결과, dodecylammonium chloide을 이용한 MMT의 유기적 개질(DA-MMT)은 약 7.3 Å의 실리케이트 층간을 증가시켰고, DA-MMT 내의 CH_(2) 기에 의해 2800~2900 ㎝^(-1)에서 새로운 피크가 나타났다. PP/DA-MMT 나노복합재료의 열안정성은 순수한 PP 수지에 비해 향상되었는데, 이는 DA-MMT 입자와 PP 사이의 분자간 상호작용에 의한 것으로 판단된다. 또한, PP/DA-MMT 나노복합재료가 높은 기계적 계면 물성을 나타냈는데, 이러한 결과는 층간이 증가된 실리케이트에 PP가 쉽게 삽입되기 때문으로 판단된다. In this work. the effect of organic modification of Na-montmorillonite (MMT) with dodecylammonium chloride on thermal stabilities and mechanical interfacial properties of PP nanocomposites was investigated. The structure and surface properties of the nanocomposites were determined by XRD and FT-IR, respectively. The thermal stabilities of the nanocomposites were studied using a TGA analysis. Also, the mechanical interfacial properties were confirmed by KIC and GIC of casting specimens. As a result, the organic modification of MMT by dodecylammonium chloride(DA-MMT) led to the increase of the silicate layers to about 7.3 A, and the new peaks at 2800∼2900 cm^(-1) hand were shown in the presence of the CH groups on the DA-MMT. The thermal stahilities of PP/DA-MMT nanocomposites were higher than that of pure PP resin, which can be attributed to the increase of intermolecular interaction between DA-MMT particles and PP matrix. Also, the PP/DA-MMT nanocomposites had higher mechanical interfacial properties than those of pristime nanocomposites. These results explained that the pp was easily inserted in the spacing of the silcate interlayers of which were increased.
Pharmacokinetics of a ginseng saponin metabolite compound K in rats
Paek, In Bok,Moon, Ya,Kim, John,Ji, Hye Young,Kim, Soon Ai,Sohn, Dong Hwan,Kim, Jae Baek,Lee, Hye Suk John Wiley Sons, Ltd. 2006 BIOPHARMACEUTICS AND DRUG DISPOSITION Vol.27 No.1
<P>The absorption, dose-linearity and pharmacokinetics of compound K, a major intestinal bacterial metabolite of ginsenosides, were evaluated in vitro and in vivo. Using the Caco-2 cell monolayers, compound K showed moderate permeability with no directional effects, thus suggesting passive diffusion. After intravenous dose (i.v.; 1, 2, and 10 mg/kg), no significant dose-dependency was found in Cl (17.3–31.3 ml/min/kg), V<SUB>ss</SUB> (1677–2744 ml/kg), dose-normalized AUC (41.8–57.8 µg·min/ml based on 1 mg/kg) and t<SUB>1/2</SUB>. The extent of urinary excretion was minimal for both i.v. and oral doses. The extent of compound K recovered from the entire gastrointestinal tract at 24h were 24.4%–26.2% for i.v. doses and 54.3%–81.7% for oral doses. Following oral administration (doses 5–20 mg/kg), dose-normalized AUC (based on 5 mg/kg) was increased at the 20 mg/kg dose (85.3 µg·min/ml) compared with those at lower doses (4.50–10.5 µg·min/ml). Subsequently, the absolute oral bioavailability (F) was increased from 1.8%–4.3% at the lower doses to 35.0% at the 20 mg/kg dose. The increased F could be related to the saturation of carrier-mediated hepatic uptake and esterification of compound K with fatty acids in the liver. Copyright © 2005 John Wiley & Sons, Ltd.</P>
Ha, Jungmin,Kim, Myoyeon,Kim, Moon Young,Lee, Taeyoung,Yoon, Min Young,Lee, Jayern,Lee, Yeong‐,Ho,Kang, Young‐,Gyu,Park, Jun Seong,Lee, John Hwan,Lee, Suk‐,Ha John Wiley & Sons 2018 Journal of the Science of Food and Agriculture Vol.98 No.6
<P>CONCLUSIONWe detected major differences in the transcriptional levels of genes involved in the biosynthesis of proanthocyanidin and anthocyanin among genotypes beginning at the early stage of seed development. The results of the present study provide insights into the underlying genetic variation in proanthocyanidin biosynthesis among soybean genotypes. (c) 2017 Society of Chemical Industry</P>
Nanoscale ripples on polymers created by a focused ion beam
Moon, Myoung-Woon,Han, Jun Hyun,Vaziri, Ashkan,Her, Eun Kyu,Oh, Kyu Hwan,Lee, Kwang-Ryeol,Hutchinson, John W IOP Pub 2009 Nanotechnology Vol.20 No.11
<P>We show that focused ion beam irradiation results in the creation of peculiar one- and two-dimensional nanoscale features on the surface of polyimide—a common polymer in electronics, large scale structures, and the automobile industry, as well as in biomedical applications. The role of ion beam incident angle, acceleration voltage, and fluence on the morphology of the structural features is systematically investigated, and insights into the mechanisms of formation of these nanoscale features are provided. Moreover, by using the maskless patterning method of the focused ion beam system, we have developed a robust technique for controlled modification of the polymeric surface. The technique, which is analogous to using a gray glass with varying darkness to control the radiation from the sun, but at a much smaller scale, enables the ion intensity and angle to be controlled at each surface point of the polymer, giving rise to structural surface features with desired shape and morphology. </P>
John J. Cheh,Il-woon Kim,Chris Moon 한국관리회계학회 2009 관리회계연구 Vol.9 No.1
미국에서 Sarbanes-Oxley 법이 2002년에 통과되어서 시행된지 7년이 지난 결과 기업회계의 신뢰도와 투명성이 많이 진작되어진 것으로 보고되고 있다. 그러나 이 법으로 인해서 기업의 감사비용 증가에 대한 불만이 많은 것도 사실이다. 본 논문은 data mining기법을 이용해서 회계내부관리제도가 취약한 기업을 미리 가려낼 수 있음을 보여주고 있다. 회계감사시에 이 기법을 적용하면 회계감사 시간의 단축과 감사비용 절감에 기여할 수 있으리라 생각된다. The Sarbanes-Oxley Act of 2002 requires management of publicly traded companies to assess their company’s internal control material weakness (MW) and to provide an internal control report as part of their periodic report to stockholders and regulators. The Public Company Accounting Oversight Board Auditing Standard 2 requires external auditors to issue an opinion on the effectiveness of their clients’ internal control. Even though the Act helped improve the quality and transparency of financial reports, a major concern has been expressed by many publicly traded companies about the increasing audit fees charged by external auditors. In this paper, we provide evidence that data mining can be used as a powerful tool to recognize and profile companies with material weaknesses in internal control. The decision tree model, in particular, reveals decision rules that can be used for auditors to assess whether a company under audi t i s more l i kel y to fall i nto the cl ass of MW compani es or the class of non-MW companies. This type of information will help auditors not only enhance the effectiveness the audit but also reduce the cost of the audit.
Moon, Byung-Seok,Katzenellenbogen, John A.,Cheon, Gi-Jeong,Chi, Dae-Yoon,Lee, Kyo-Chul,An, Gwang-Il Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.6
It is important to identify selective ligands for the estrogen receptor subtypes ER$\alpha$ or ER$\beta$ to evaluate them as pharmaceutical targets in breast cancer. To develop ER$\beta$-selective ligands as PET imaging agents, a series of aryl indazole estrogen analogues substituted at the C3 position with fluoroethyl and fluoropropyl groups were synthesized and evaluated for their relative binding affinities and selectivities for ER$\alpha$ vs ER$\beta$. The fluoroethylated indazole estrogen (FEIE, 1i) and fluoropropylated indazole estrogen (FPIE, 1h) showed 41- fold and 17-fold ER$\beta$/ER$\alpha$ selectivity, respectively. However, their binding affinities to ER$\alpha$ and ER$\beta$ were very low.