• Bulletin of the Korean Chemical Society
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• 제23권5호
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• pp.705-707
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• 2002

Stability constants of complexes of aluminium(III) and thorium(IV) with methionine and cysteine have been determined by modified paper electrophoretic technique at $\mu$ = 0.1 M. The proportion of ionic species of methionine and cysteine were varied by changing pH of background electrolyte. The stability constants of the complexes metal-methionine-cysteine have been found to be 4.31 ± 0.12 and 5.40 ± 0.19 (log K values) for $Al^{3+}\;and\;Th^{4+} $ complexes, at temperature 35 ${^{\circ}C}$, respectively.

• Korea-Australia Rheology Journal
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• 제20권3호
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• pp.97-107
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• 2008

This article presents an overview of current research activities that center on colloidal crystals resulting from self-assembly of surface-charged nanoparticles. It is organized into three parts: the first part discusses characterization of colloidal structures, the second part describes colloidal stability from the rheological aspects of colloidal crystals suspended in medium, and the third part highlights polymerized colloidal crystals as a promising application. Finally, we briefly discuss the directions of future research in this area.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.809-812
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• 2004

Complexation reactions of nitrilotriacetate (NTA) and penicillamine with $Cu^{2+}$ and $Co^{2+}$ have been studied in solution phase using paper electrophoresis technique. The stability constants of the complexes Cu(II)-nitrilotriacetate-penicillamine and Co(II)-nitrilotriacetate-penicillamine have been found to be $6.64{\pm}0.03\;and\;5.86{\pm}0.05$ (logarithm stability constant values), respectively at 35$^{\circ}C$ and ionic strength 0.1 M.

• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.179-182
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• 2001

Photocyclizable poly(cinnam-4'-yl methyl methacrylate) derivatives bearing methoxy benzene (PMCMMA), anthracene (PACMMA), and coumarin (PCCMMA) have been synthesized via Heck type reaction. Three different types of polymers are photoreactable usin g linearly polarized UV light and applicable as liquid crystal alignment layer. Anthracence and coumarin containing polymers (PACMMA, PCCMMA) have better thermal stability than PMCMMA. This observation may be attributed to the glass transition temperature elevation due to the bulky size and another photocrosslinking site provided by anthracene or coumarin group.

• Bulletin of the Korean Chemical Society
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• 제7권3호
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• pp.204-210
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• 1986

It is shown that the linear stability coincides with the thermodynamic stability in the case of stress tensor evolution for simple dense fluids even if the constitutive (evolution) equation for the stress tensor is nolinear. The domain of coincidence can be defined in the space of parameters appearing in the constitutive equation and we find the domain is confined in an elliptical cone in a three-dimensional parameter space. The corresponding state theory in rheology of simple dense fluids is also further examined. The validity of the idea is strengthened by the examination.

• Journal of Pharmaceutical Investigation
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• 제38권2호
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• pp.127-134
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• 2008

Peroral administration is the most convenient one for the administration of pharmaceutically active compounds. Most of poorly water-soluble drugs administered via the oral route, however, remain poorly available due to their precipitation in the gastrointestinal (GI) tract and low permeability through intestinal mucosa. In this study, one of drug delivery carriers, lipid nanoparticles (LNPs) were designed in order to reduce side effects and improve solubility and stability in GI tract of the poorly water soluble drugs. However, plain LNPs are generally unstable in the GI tract and susceptible to the action of acids, bile salts and enzymes. Accordingly, the surface of LNPs was modified with polyethylene glycol (PEG) for the purpose of improving solubility and GI stability of paclitaxel (PTX) in vitro. PEG-modified LNPs containing PTX was prepared by spontaneous emulsification and solvent evaporation (SESE) method and characterized for mean particle diameter, entrapping efficiency, zeta potential value and in vitro GI stability. Mean particle diameter and zeta potential value of PEG-modified LNP containing PTX showed approximately 86.9 nm and -22.9 mV, respectively. PTX entrapping efficiency was about 70.5% determined by UV/VIS spectrophotometer. Futhermore, change of particle diameter of PTX-loaded PEG-LNPs in simulated GI fluids and bile fluid was evaluated as a criteria of GI stability. Particle diameter of PTX-loaded PEG-LNPs were preserved under 200 nm for 6 hrs in simulated GI fluids and bile fluid at $37^{\circ}C$ when DSPE-mPEG2000 was added to formulation of LNPs above 4 mole ratio. As a result, PEG-modified LNPs improved stability of plain LNPs that would aggregate in simulated GI fluids and bile solution. These results indicate that LNPs modified with biocompatible and nontoxic polymer such as PEG might be useful for enhancement of GI stability of poorly water-soluble drugs and they might affect PTX absorption affirmatively in gastrointestinal mucosa.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.357.1-357.1
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• 2014

Superhydrophobic WOx nanowire (NW) arrays were fabricated using a thermal evaporation and surface chemistry modification methods by self-assembled monolayer (SAM). As-prepared non-wetting WOx NWs surface shows water contact angle of $163.2^{\circ}$ and has reliable stability in underwater conditions. Hence the superhydrophobic WOx NWs surface exhibits silvery surface by total reflection of water layer and air interlayer. The stability analysus of underwater superhydrophobicity of WOx NWs arrays was conducted by changing hydrostatic pressure and surface energy of WOx NWs arrays. The stability of superhydrophobicity in underwater conditions decreased exponentially as hydrostatic pressure applied to the substrates increased3. In addition, as surface energy decreased, the underwater stability of superhydrophobic surface increased sharply. Specifically, sueprhydrophobic stability increased exponentially as surface energy of WOx NWs arrays was decreased. Based on these results, the models for explaining tendencies of superhydrophobic stability underwater resulting from hydrostatic pressure and surface energy were designed. The combination of fugacity and Laplace pressure explained this exponential decay of stability according to hydrostatic pressure and surface energy. This study on fabrication and modeling of underwater stability of superhydrophobic W18O49 NW arrays will help in designing highly stable superhydrophobic surfaces and broadening fields of superhydrophobic applications even submerged underwater.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.601-601
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• 2013

Superhydrophobic W18O49 nanowire (NW) arrays were synthesizedusing a thermal evaporation and surface chemistry modification methods by self-assembled monolayer (SAM). As-prepared non-wetting W18O49 NWs surface shows water contact angle of $163.2^{\circ}$ and has reliable stability in underwater conditions. Hence the superhydrophobic W18O49 NWs surface exhibits silvery surface by total reflection of water layer and air interlayer. The stability analysus of underwater superhydrophobicity of W18O49 NWs arrays was conducted by changing hydrostatic pressure and surface energy of W18O49 NWs arrays. The stability of superhydrophobicity in underwater conditions decreased exponentially as hydrostatic pressure applied to the substrates increased3. In addition, as surface energy decreased, the underwater stability of superhydrophobic surface increased sharply. Specifically, sueprhydrophobic stability increased exponentially as surface energy of W18O49 NWs arrays was decreased. Based on these results, the models for explaining tendencies of superhydrophobic stability underwater resulting from hydrostatic pressure and surface energy were designed. The combination of fugacity and Laplace pressure explained this exponential decay of stability according to hydrostatic pressure and surface energy. This study on fabrication and modeling of underwater stability of superhydrophobic W18O49 NW arrays will help in designing highly stable superhydrophobic surfaces and broadening fields of superhydrophobic applications even submerged underwater.

• 대한화학회지
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• 제18권6호
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• pp.443-446
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• 1974

內然機關에서 採取한 廢油를 黃酸白土 處理하여 얻어진 再生油는 원래 들어 있던 添加劑, 特히 酸化防止劑와는 相關없이 酸化安定性이 좋아졌다. 이러한 性質의 改善은 芳香族化合物이 거의 25%나 增加하는 事實로 미루어 耐酸化性物質의 生性에 基因하는 것으로 考察된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.481-483
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• 1998

The problem of production of new materials based on polyheteroarylenes and other polymers combining good mechanical and dielectric properties. radiation and chemical stability with heat- and thermal stability is related with the development of efficient synthesis technique of starting low-molecular compounds. Alicyclic dianhydrides are believed to be the promising monomers to synthesize various polymers.