Kolon Central Research Park

Yongin, South Korea

Kolon Central Research Park

Yongin, South Korea
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Kweon J.H.,Konkuk University | Jung J.H.,Konkuk University | Lee S.R.,Konkuk University | Hur H.W.,Hanwha Eco Institute | And 2 more authors.
Desalination | Year: 2012

Chemical cleaning is one of the main strategies to reduce membrane fouling. Effects of consecutive chemical cleaning on microfiltration were investigated with two feed waters; Feed 1 has a low turbidity of 12-55. NTU and Feed 2 has a high turbidity of 343-678. NTU. One cycle of the chemical cleaning was 1st alkaline wash with NaOH and NaOCl, acid wash with citric acid, and 2nd alkaline wash with NaOCl. The cleaning efficiency on flux recovery for experiments with both the two feed waters was decreased with increasing number of filtration cycle with periodic chemical cleaning although the reduced efficiency was substantial with Feed 2. According to membrane surface properties by atomic force microscopic images and roughness and contact angle measurement, the inadequate removal of organic foulant from membrane surface probably aggravated the flux decline with the membrane exposed to several cycles of filtration with the periodic chemical cleaning. © 2011 Elsevier B.V.

Kim H.-J.,Yonsei University | Kang Y.-G.,Yonsei University | Park H.-G.,Yonsei University | Lee K.-M.,Kolon Central Research Park | And 3 more authors.
Liquid Crystals | Year: 2011

We explored the doping effects of zirconium dioxide (ZrO2) nanoparticles on the characteristics of liquid crystal (LC) devices. The electro-optic (EO) properties of LCs with various doping contents were changed. The addition of ZrO2 nanoparticles contributed to an improvement in EO properties in nematic LC cells such as low voltage operation and fast response time. The LC cells with 1.5 wt% ZrO2 nanoparticles showed the lowest threshold voltage (0.8 V) and the fastest response time (14.5 ms), and especially, a rise time of 0.7 ms, which can be applied for use in advanced LC devices. © 2011 Taylor & Francis.

Chae H.S.,Sungkyunkwan University | Lee H.S.,Kolon Central Research Park | Kang C.S.,Kolon Central Research Park | Lee J.Y.,Sungkyunkwan University | Park Y.H.,Sungkyunkwan University
Molecular Crystals and Liquid Crystals | Year: 2010

Spectrum defects such as hot band and rainbow spectra on back light unit (BLU) composed of prism film and diffusing film have been examined by optical analysis. Hot band and rainbow phenomenon could be resulted from rapid luminance decrease and fluctuation in spectra at viewing angles in the range of 30-40° and 50-70°, respectively. By optical simulation with modification in prismatic structure, it is suggested that spectrum defects could be diminished or eliminated in both calculated simulation and practical prism pattern when the plane structure of prism is changed from straight to slow curved.

Park J.M.,KOLON Central Research Park | Lee J.Y.,Sungkyunkwan University | Park Y.H.,Sungkyunkwan University
Macromolecular Research | Year: 2010

Eco-friendly flame retardant poly(butylene terephthalate) copolymers (FR-PBTs) were synthesized with various amounts (5.5, 8, 10 and 15%) of the flame retardant, phosphorous comonomer unit, [(6-oxido-6H-dibenz <1,2>oxaphosphorin-6-yl)methyl]-methyl butanedioate (DOP-MBDA). Thermal stability was determined by TGA and the resistance to hydrolysis was examined by comparing the inherent viscosities of the polymers before and after hydrolysis in a 10 wt% aqueous NaOH solution at 130°C for 8 h. Unfortunately the thermal stability and hydrolytic resistance of the copolymer decreased gradually with increasing DOP-MBDA content up to 10%. However, when the DOP-MBDA content was increased from 10 to 15% (FR-PBT-15), the thermal stability and hydrolytic resistance improved dramatically to those of the PBT homopolymer. FTIR spectroscopy showed that the ratio of the trans to gauche moiety in the copolymer chain decreased with increasing DOP-MBDA content up to 10%, whereas the ratio increased when 15% DOP-MBDA was incorporated into the polymer. The higher trans to gauche ratio suggests that crystallization may take place more readily in FR-PBT-15. In addition, FR-PBT-15 showed the highest density and degree of crystallinity among the copolymers. The improved thermal stability and resistance to hydrolysis of FR-PBT-15 was attributed to the denser stereo-stable crystal structure of the polymer. © 2010 The Polymer Society of Korea and Springer Netherlands.

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