• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.04a
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• pp.119-122
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• 2003

We report a dramatic increase in the photo-stability of a blue-emitting polymer, poly(9,9-dioctylfluorene), achieved by the addition of gold nanoparticles to the polymer. The optical absorption band of gold nanoparticles is tuned to resonate the triplet exciton-ground state band gap energy of the polymer. The photo-oxidation rate of poly(9,9-dioctylfluorene) was drastically reduced by doping the polymer with a very small amount ($10^{-6}-10^{-5}$ volume fraction) of gold nanoparticles. The gold nanoparticles used herein act as the quenching agent of the triplet states and can be directly applied to various blue light emitting polymer thin film ( < 100 nm ) devices.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.169-172
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• 2003

Manufacturing process for autonomic microcapsules was introduced and autonomic microcapsules were manufactured by varying with various manufacturing process variables. Urea-formaldehyde resin was used for the wall of microcapsules and DCPD (dicyclopentadiene) was used for the self-healing agent. The characteristics of these microcapsules was evaluated through a particle size analyaer, an optical microscope, and a TGA. The various manufacturing process variables, such as pH and agitation speed of the emulsified solution, were considered to focus in this study. According to the results, the particle size distributions were affected on the agitation speed of the emulsified solution, and the thermal stability was influenced by pH of the emulsified solution.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.934-937
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• 1998

Charge/discharge property of LiMn2O4 was investigated with LiMn2O4/Li cell for use of lithium ion battery in electric vehicle. LiMn2O4 calcined at $800^{\circ}C$ for 36hr show high charge/discharge capacity and excellent cycle stability than that of others. This is found to be in agreement with expectation in the X-ray diffraction analysis. In addition, the kind and volume of conductive agent involved in LiMn2O4 cathode is excellent at super-s-black and 20wt%, respectively.

• KSBB Journal
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• v.28 no.3
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• pp.202-207
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• 2013

In this study, saponin content of extract from modified preconditioning process was investigated in Saponaria officinalis L. for cosmetic natural surfactant. Saponin content in steamed leaves from S. officinalis L. was about three times more than that in dried leaves (tea saponin and quillaja saponin). And saponin extracts from steamed leaves was excellently shown in both forming force and forming stability. In emulsion activity, saponin extracts from steamed leaves had a similar level to quillaja saponin and tea saponin. Saponin extracts from steamed leaves in S. officinalis L. showed nontoxic effect below in $1,000{\mu}g/mL$ of concentration and dose-dependent inhibition of NO production. From the experiment, the extracts of S. officinalis L. showed good cosmetic agent.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.151-152
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• 2005

Both $Al_2O_3$ and AlN nanopowders with diameters from ${\mu}m$ to mm were bead-milled and surface-modified by stabilizing agent. The size of bead-milled nanoparticles compared with the primary powder was effectively decreased and was dependent on milling time and bead size. The results of dispersion stability analysis indicated that chemical bonding between nanoparticles and surfactant is more effective than chemical adsorption to prepare the stable transformer oils containing nanoparticles. In this study, the thermal conductivity of the transformer oils containing nanoparticles was measured by transient hot-wire and laser flash methods.

• Microbiology and Biotechnology Letters
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• v.24 no.2
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• pp.206-212
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• 1996

The strain producing bioemulsifier was isolated from soil samples. The isolated strain was identified as the genus Acinetobacter through its morphological, cultural and physiological characteristics. The highest emulsification activity and stability by Acinetobacter sp. BE-254 was observed after 5 days of cultivation in the culture medium containing n-hexadecane 4%, NaNO$_{3}$ 0.2%, KH$_{2}$PO$_{4}$ 0.01%, MgSO$_{4}$-7H$_{2}$O 0.01%, CaCl$_{2}$ 0.01%, and yeast extract 0.01%. The optimum pH and temperature for bioemulsifier production were pH 7.0 and 30$\circ$C, respectively. Furthermore the most of bioemulsifier was produced during the exponential growth phase, and this suggested that the bioemulsifier production was growth-associated. The bioemulsifier showed good emulsification activity on various emulsifying substrates such as hydrocarbons, edible oils, and petroleum fractions.

• Journal of the Korean Chemical Society
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• v.24 no.3
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• pp.239-244
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• 1980

An anion exchange method for separating the individual rare earth elements in monazite into enriched fractions has been developed. The complexed rare earth ions with EDTA at pH 8.4 pass through the anion resin bed. The absorption order of the complexed ions was in accord with that of the stability constants of the complexes. The elution of a mixture of all the rare earths through an ion-exchange bed with an ammonia-buffered solution of EDTA indicated that this chelating agent is as effective for separating the light rare earths. The separation results of each ion obtained from their elution fractions are 55% to 98%.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.107-107
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• 2013

Many nanomaterials are being harnessed as critical components in various systems for biomedical applications including diagnosis, imaging, and drug delivery. Those systems necessitate biocompatibility and low toxcity within effective dose range while achieving enough efficacy. Even though many nanomaterials enjoy successful demonstrations in bioapplications, lack of biocompatibility and high cytotoxicity often become hurdles for practical bioapplications. On the other hand, it is important to achieve enough efficiency based on chemically well-defined systems with efforts to understand mechanism at molecular level. Here, we developvarious biocompatible nanomaterials based on simple procedure using dextran as both reducing agent and surface coating. Dextran is one of the popular biocompatible polymers that have been used for drug delivery and biosensors. Dextran coated nanomaterials showed excellent colloidal stability, flexible surface chemistry for conjugation of bioactive molecules and low cytotoxicity with successful demonstrations in various bioapplications.

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.306.2-307
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• 2001

• Journal of the Korean Home Economics Association
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• v.32 no.2
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• pp.161-178
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• 1994

The purpose of this study were to investigate the current problems of family in adolescents' college entrance examination and to propose the practical alternatives about effective overcoming strategies. To study these objectives two kinds of sample and questionnaire were selected and the data were obtained through 360 parent-child pairs and 802 college preparatory institute students living in Seoul Taejon and kwangju. The major findings were as follow: 1. Educational achievements were affected by adolescents' personal traits as achievement need self-regulation emotional stability and self-concept but parents ' over-aspirations were negative agent for stress coping. 2. Parent-adolescent intimate and self-regulated relationships were positive factors for achievement and educational self-concept. Also adolecsents' educational aspirations were more significantly affected by parents' emotional supports. 3. Family stress were mediated by parent-child conflict so satisfied parent-child relationships can protect serious stressors as examination problems. Especially father-related factors were importantly revealed. In conclusion adolescent family and society must develop coping methods individually and cooperatively through family life education systematic policy and educational reformation.