• Macromolecular Research
• /
• v.10 no.1
• /
• pp.49-52
• /
• 2002

Rod-coil amphiphilic block copolymers, PALG-PEOs, poly(alkyl $\alpha$, L-glutamate-co-ethylene oxide)s, were successfully synthesized in three steps: 1) esterification of L-glutamic acid, 2) synthesis of ${\gamma}$-alkyl L-gultamate N-carboxyanhydride, and 3) polymerization of NCA monomers. These molecules form polymeric micelles with the hydrophobic core and hydrophilic corona in aqueous solution, which were characterized by light scattering and static fluorescence measurement.

• Proceedings of the PSK Conference
• /
• 2002.10a
• /
• pp.409.1-409.1
• /
• 2002

For the development of a biocompatible nano-scale drug carrier. hydrophilic polysaccharide pullulan was hydrophobized by the conjugation with fatty acid. The synthesized polymers were characterized by the measurements of fourier transform infrared (FT -IR) spectroscopy and 1H -nuclear magnetic resonance (NMR) spectroscopy. In aqueous solution. hydrophobically modified puliulan was self-assembled and structured into the core-shell type nanoparticles. (omitted)

• Proceedings of the PSK Conference
• /
• 2003.10b
• /
• pp.248.3-249
• /
• 2003

Objectives: Galatosylated PEI was synthesized and characterized for gene delivery to hepatocytes. It was modified by conjugating with hydrophilic PEG to improve in vivo circulation. And we studied the possibility as an imaging modality for monitoring of gene delivery using gal-PEI derivatives. Methods: The substitution values of galactose in PEI were calculated by resorcinol/sulfuric acid method and quantity of PEG was calculated by comparing NMR peak. Cytotoxicity was determined by MTT. (omitted)

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1371-1372
• /
• 2007

In this study, in order to confirm the application possibility to the molecular electronic device, morphlogical property of the Arachidic acid was investigated. We have investigated morphology by BAM image and AFM. ${\pi}$-A curves investigated surface pressure of this LB film from liquid to solid state ranged between 40 to 45 mN/m. BAM images investigated the different states of Arachidic Acid LB film. When the surface pressure reaches at 40 mN/m, the monolayer was deposited onto the hydrophilic glass substrates by Y-type deposition. We also investigated the frequency characteristics of LB modified glass by QCM. We investigated morphology of arachidic acid by AFM. As a result, we obtained the frequency characteristic and morphology of LB films from controlling the deposited layers.

• Journal of Radiation Industry
• /
• v.8 no.1
• /
• pp.53-57
• /
• 2014

The kenaf is quickly developing as a renewable resource. Kenaf can be grown under a wide range of weather conditions. Modification of kenaf fiber by graft polymerization provides a significant route to alter the chemical properties, including surface hydrophilicity or hydrophobicity. In this study, kenaf fiber surfaces were grafted with acrylic acid as a hydrophilic group using electron beam irradiation. The grafting rate increased with an increase in grafting time. The FT-IR results confirmed that acrylic acid was successfully grafted onto the kenaf fibers. The wettability of the kenaf fiber was increased, accompanied by acylic acid grafting on the fiber surface. According to the permeability test result, it was found that acrylic acid grafted kenaf fiber reinforced cement composite was more reduced than non-grafted kenaf fiber reinforced cement composite.

• 한국해양학회지
• /
• v.29 no.2
• /
• pp.171-182
• /
• 1994

Dissolved free amino acid (DFAA) dissolved hydrolyzable amino acid (DHAA) and D/L amino acid racemic ratio in the dissolved organic compounds were studied to investigate the biogeochemical characteristics of dissolved organic compound in the Yellow Sea. Concentration of total DFAA ranged from 0.06 uM to 0.26 uM in the study area. DFAA composition showed that aspiratae, glutamate, serine, glycine and alanine were predominant. According to characteristics of functional group of amino acid, these belonged to hydroponic group. C-18 short column cartridge (Sep-Pak) activated by methanol was used to extract organic macromolecules in the seawater. In operational scheme, macromolecules were divided into two fractions. Geomacromolecule fraction eluted with 50% methanol was used to extract organic macromolecules in the seawater. In operational scheme, macromolecules were divided into two fractions. Geomacromolecule fraction eluted with 50% methanol was moderately hydrophilic and showed characteristics of humic substance in the seawater. Biomacromolecule fraction eluted with 100% methanol was hydrophobic and most abundant in the surface seawater samples. DHAA was much higher than DFAA in this study area. DHAA ranged from 2.05 uM to 6.19 uM in the B-fraction and from 8.13 uM to 24.46 uM in the G-fraction. DHAA was higher in the surface water than in the bottom water where the vertical stratification developed well. The result of HPLC analysis of D/L amino acid showed that low racemic ratio was found in the B-fraction. It implies that the B-fraction is relatively younger than the G-fraction and freshly derived from biosphere.

• Transactions of the Korean hydrogen and new energy society
• /
• v.2 no.1
• /
• pp.7-13
• /
• 1990

We are interested in studying the artificial photolysis of water which mimics the natural plant photosynthesis. In the artificial system there should be a proper photosensitizer, electron donor and electron acceptor. Since Mn-tetramer is known to be the essential part for the oxygten-evolving system in the natural photosynthesis, it is important to know or study the reactivity of Mn-porphyrins. As a model for the Mn-tetramer in the natural photosynthesis, we prepared the lipophilic and hydrophilic Mn-porphyrins. For the lipophilic porphyrin with long hydrocarbon chain, the long hydrocarbon chain was inserted in the porphyrin ring formation step. For the hydrophilic porphyrin, the porphyrin was sulfonated with sulfuric acid. These syntheses of lipophilic and hydrophilic Mn-porphyrins are significant, since the behaviors of these compounds will be different in the microemulsions or vesicles. We also found that the Mn-porphyrins were photoreduced in the microemulsion and water in the presence of amines.

• Journal of the Korean Magnetics Society
• /
• v.4 no.4
• /
• pp.326-334
• /
• 1994

This paper describes the fabrication of the hydrophilic magnetic fluid with high viscosity and its application to oil seal apparatus used with the Nd-permanent magnet. The results are as follows. 1) The ultrafine magnetite particles under the size of $100\;{\AA}$ are first coated by the oleic acid ion and again adsorbed by the hydrophilic D. B. S. ion, and there by hydrophilic magnetic fluid with high viscosity could be made by dispersing them into the ethylene glycol. 2) In development of the oil seal apparatus using magnetic fluid and Nd-permanent magnet, the viscosity and magnetic susceptibility show high when the $Fe_{3}O_{4}$ content is over 50%(g/cc) in the fluid, so that such properties could improve highly the capability of oil seal. 3) The maximum of the resisting pressure of the oil seal using the ethylene glycol base magnetic fluid and the Nd-permanent magnet, is about $50\;g/\textrm{cm}^2$, under the condition of this experiment. Therefore the oil seal may not be suitable for the ship engine and the driving part of the automobile, and thus it needs a lot further complementary reserch. However, it is quite favourable for such an oil seal apparatus as speed reducer under the condition of atmospheric pressure.

• Journal of the Korean Magnetics Society
• /
• v.9 no.2
• /
• pp.121-126
• /
• 1999

This paper describes a fabrication of Fe-dispersed hydrophilic magnetic fluid and its application to oil seal in combination with the Nd-permanent magnet. The results are as follows; 1) Using silica coated iron particle of magnetization of 125.5 emu/g (at 10 kOe) and the mean particle size of 100 $\AA$, after multiple adsorption to the surface of silica coated iron particle with oleic acid ion, D.B.S. and T.M.A. ion, hydrophilic Fe-magnetic fluid [70 %(g/∝)Fe, magnetization of 52 emu/g and viscosity of 1450 cp] can be produced by dispersing the iron particle in ethylene glycol solution. 2) The oil seal apparatus consisting of six stages of Nd-permanent magnet (3200 Gauss) and Fe-magnetic fluid [70 %(g/∝) Fe] showed an excellent pressure resistance of 7400 g/$\textrm{cm}^2$ under the gap between shaft and oil seal was 0.2 mm.

• Nuclear Engineering and Technology
• /
• v.5 no.2
• /
• pp.103-114
• /
• 1973

Radiation grafting of acrylic acid and 4-vinylpyridine at room temperature has been studied by an impregnation method to improve the hygroscopic properties, the antistatic behavior and the dyeability of polyester fabric. Polyester fabric was impregnated with acrylic acid or aqueous emulsion of acrylic acid-4-vinylpyridine by immersion at 25$^{\circ}$or 7$0^{\circ}C$. The impregnated fabric was irradiated under nitrogen gas with ${\gamma}$-rays from Co-60. When acrylic acid grafted polyester fabric was treated with sodium carbonate, calcium acetate and potassium persulfate, tne rate of water absorption was increased and most parts of polyacrylic acid formed were extracted off from the fabric with 0.1% solution of sodium hydroxide at 10$0^{\circ}C$. In the case of the impregnation of a mixture of acrylic acid and 4-vinylpyridine the petcent of grafting has been shown to be proportional to the ratio of 4-VP/AA and radiation dost. Estimating by contact angle measurements of water on the various polymer surfaces, the antistatic behavior was decreased with the increase of grafting percent. The investigation of electron micrograph disclosed the existence of certain type of discontinuities in the acrylic acid grafted polyester fiber which was treated with various salts.