Gyeongnam Science High School

Chinju, South Korea

Gyeongnam Science High School

Chinju, South Korea
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Lee J.D.,Gyeongsang National University | An T.H.,Gyeongsangnamdo Institute of Science Education | Noh H.G.,Gyeongnam Science High School | Kim S.G.,Kwandong Middle School | Choi Y.R.,Samhyun Girs High School
Japanese Journal of Applied Physics | Year: 2010

The cobalt thin films were directly grown on n-Si(100) substrates in a non-aqueous electrolyte of 0.1M CoCl2 by using pulsed electrodeposition technique. In this paper, the growth, structural and magnetic properties of thin Co films have been investigated. Current transient experiments showed that Co nuclei in the early deposition stage forms through three dimensional (3D) instantaneous nucleation followed by diffusion-limited growth. From the atomic force microscopy (AFM) analysis, it has been found that the film surface consisted of cubic and distorted rectangularshaped nanocrystallites with the average size of about 140nm irrespective of the deposition voltage. X-ray diffraction (XRD) measurement indicated that Co was arranged with only a hexagonal close-packed (hcp) structure not involving face-centered cubic (fcc) Co or silicide phases. Vibrating sample magnetometer (VSM) measurements revealed that the easy magnetization axis of Co thin film is parallel to the film plane. © 2010 The Japan Society of Applied Physics.


Min K.S.,Kyungpook National University | Park A.H.,Gyeongnam Science High School | Shin J.W.,Kyungpook National University | Rowthu S.R.,Kyungpook National University | And 2 more authors.
Dalton Transactions | Year: 2010

Chiral copper(ii) complexes of the types [CuII(R/S-ppme) 3](ClO4)2 and [CuII(R/S-ppme) 2(SO4)] have been synthesized by reactions of Cu(ClO 4)2·6H2O and CuSO4· 5H2O with R/S-ppme in methanol under aerobic conditions (R/S-ppme = (R/S)-(±)-1-phenyl-N-(pyridine-2-ylmethylene)ethanamine). All complexes were isolated and characterized by X-ray crystallography and circular dichroism (CD): (Λ)-[CuII(R-ppme)3](ClO4) 2 (1), (Δ)-[Cu(S-ppme)3](ClO4) 2·H2O (2), (Δ)-[CuII(R-ppme) 2(SO4)]·4CH3OH (3), and (Λ)-[CuII(S-ppme)2(SO4)]·4CH 3OH (4). 1 and 2 with ClO4 - anions are formed as tris(R/S-ppme) copper(ii) complexes, while 3 and 4 with SO4 2- are formed as bis(R/S-ppme) copper(ii) complexes. The structures of 1 with R-ppmes and 4 with S-ppmes show the same absolute configurations (Λ). In contrast, 2 with S-ppmes and 3 with R-ppmes exhibit Δ configurations. In the electron paramagnetic resonance (EPR) spectra of 1 and 3, both compounds demonstrate z-axis elongated structures. The CD spectra of 1 and 2 show Cotton effects in an enantiomeric pattern; those of 3 and 4 also display the same effects. © 2010 The Royal Society of Chemistry.


Kwon J.H.,Gyeongnam Science High School | Kwon J.H.,Gyeongsang National University | Kwon J.H.,Pohang University of Science and Technology | An J.-Y.,Gyeongnam Science High School | And 20 more authors.
ACS National Meeting Book of Abstracts | Year: 2010

A new semiconducting poly[(bithiophenyl acrylronitrile)-co-2,5-[(1,4-didecyloxy)naphthalene]) (PBTADN), an alternating copolymer of bithiophenyl acrylronitrile and (didecyloxy)naphthalene, is synthesized and used as an active material for organic thin film transistors (OTFTs) and organic solar cells. Incorporating bithiophenyl acrylronitrile as an electron deficient group and didecyloxy naphthalene as an electron rich group resulted in a relatively low bandgap, high charge carrier mobility, and finally good photovoltaic performances of PBTADN solar cells. The maximum power conversion efficiency of the PBTADN:PC71BM solar cell reached 2.9 % with a Voc of 0.88 V, a short circuit current density (Jsc) of 5.6 mA/cm2, and a fill factor of 59.1 %. The molecular weight dependence of morphology, charge carrier mobility and finally the photovoltaic performances were also studied and it was found that high molecular weight PBTADN has better self assembly characteristics, showing enhanced performance.


Park W.S.,Gyeongsang National University | Kim H.J.,Gyeongsang National University | Chung H.-J.,Gyeongsang National University | Chun M.S.,Korea Science Academy | And 7 more authors.
Journal of the Korean Society of Food Science and Nutrition | Year: 2015

Lettuce (Lactuca sativa) is an important dietary leafy vegetable that is primarily consumed as a fresh or salad material. It has a number of cultural varieties with green and/or red color. Carotenoids and anthocyanins are known to be responsible for these two colors, respectively. In this study, carotenoid and anthocyanin contents were determined to evaluate the stability of these functional pigments during storage at home. Analyses were carried out at the beginning, 3, 6, 9, and 12 days after harvest. In the course of storage at room temperature, total carotenoid levels rapidly decreased, and the decrease was found to be greatest during the first 3 days. Meanwhile, carotenoid level slightly changed within the first 9 days at 4°C after harvest. This result suggests that carotenoids in green lettuce are more stable when refrigerated than at room temperature. Meanwhile, total anthocyanin content in red lettuce did not significantly decrease during storage at room temperature and 4°C, which indicates that anthocyanins have higher stability during storage compared with carotenoids in green lettuce. Anthocyanin extract exhibited higher antioxidant activity than carotenoid extract based on 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonic acid) (ABTS) radical scavenging assay. Antioxidant activity of anthocyanin extract may also be estimated directly by the presence of another potent hydrophilic antioxidant compound, which is ascorbic acid in this extract. In addition, anthocyanin extract showed about a 5-fold higher amount of anthocyanins than carotenoids in the carotenoid extract. The high correlation between carotenoid content with ABTS radical scavenging activity indicates that ABTS assay is more suitable than 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay for detecting antioxidant capacity of carotenoid extract from lettuce. © 2015, Korean Society of Food Science and Nutrition. All rights reserved.


Moon J.-Y.,Gyeongnam Science High School | Kim S.-W.,Gyeongnam Science High School | Yun G.-M.,Gyeongnam Science High School | Lee H.-S.,Gyeongnam Science High School | And 5 more authors.
Animal Cells and Systems | Year: 2015

The purpose of this study was to examine the effect of amygdalin on cell growth and telomerase activity in human cancer and MRC-5 fibroblast cell lines. The level of β-glucosidase activity for releasing cyanide was significantly (P <.05) higher in cancer cell lines (A-549, MDA-MB-231, MCF-7 and U87-MG) than in MRC-5 fibroblasts. Growth rate of cancer cells was apparently inhibited in concentrations above 10 mg/ml amygdalin with senescent-like abnormal morphology. Whereas the effects were absent or marginally detected in MRC-5 fibroblasts. High incidence of β-galactosidase activity was observed in amygdalin-treated cancer cells, compared with that of untreated control while no difference was observed between the control and amygdalin-treated MRC-5 fibroblasts. Furthermore, level of telomerase activity was significantly (P <.05) higher (∼8–13 fold) in cancer cell lines along with high expression of telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC) than in MRC-5 fibroblasts which did not expressed TERT and TERC. However, telomerase activity was significantly (P <.05) down-regulated in amygdalin-treated cancer cells with the decreased expression of TERT and TERC compared with control cancer cells. There were no difference in the telomerase activity between control and amygdalin-treated MRC-5 fibroblasts. Based on these observations, we concluded that amygdalin treatment offers a valuable option for the cancer treatment, causing inhibition of cell growth and down-regulation of telomerase activity in human cancer cell lines by increasing β-glucosidase activity. © 2015 Korean Society for Integrative Biology.


Bae D.S.,Gyeongnam Science High School | Lee D.-H.,Gyeongnam Science High School | Eim D.E.,Gyeongnam Science High School | Hu S.-E.,Gyeongnam Science High School | And 4 more authors.
Molecular Crystals and Liquid Crystals | Year: 2013

New fluorene based light emitting polymer, poly[(4-(9,9-didecyl-9H-fluoren- 2-yl) phenyl)dimethyl(phenyl)silane] (PFDPS), was synthesized by palladium-catalzed Suzuki coupling reaction. The obtained copolymer was characterized by 1H-NMR, and IR-spectroscopy. The polymer showed good solubility in common organic solvents and weight average molecular weight of 16,300 with polydispersity index of 1.4. The maximum photoluminescence of the solution and film of the polymer was observed at 392 nm and 410 nm, respectively. The double-layered device with the configuration, ITO/PEDOT/PFDPS/LiF/Al structure has a turn-on voltage at about 5.5 V and maximum brightness of 9.40 cd/m2, and emitted violet light at 414 nm. Copyright © Taylor & Francis Group, LLC.


Moon J.-Y.,Gyeongnam Science High School | Kim S.-W.,Gyeongnam Science High School | Yun G.-M.,Gyeongnam Science High School | Lee H.-S.,Gyeongnam Science High School | And 5 more authors.
Animal Cells and Systems | Year: 2015

The purpose of this study was to examine the effect of amygdalin on cell growth and telomerase activity in human cancer and MRC-5 fibroblast cell lines. The level of β-glucosidase activity for releasing cyanide was significantly (P < .05) higher in cancer cell lines (A-549, MDA-MB-231, MCF-7 and U87-MG) than in MRC-5 fibroblasts. Growth rate of cancer cells was apparently inhibited in concentrations above 10 mg/ml amygdalin with senescent-like abnormal morphology. Whereas the effects were absent or marginally detected in MRC-5 fibroblasts. High incidence of β-galactosidase activity was observed in amygdalin-treated cancer cells, compared with that of untreated control while no difference was observed between the control and amygdalin-treated MRC-5 fibroblasts. Furthermore, level of telomerase activity was significantly (P < .05) higher (∼8–13 fold) in cancer cell lines along with high expression of telomerase reverse transcriptase (TERT) and telomerase RNA component (TERC) than in MRC-5 fibroblasts which did not expressed TERT and TERC. However, telomerase activity was significantly (P < .05) down-regulated in amygdalin-treated cancer cells with the decreased expression of TERT and TERC compared with control cancer cells. There were no difference in the telomerase activity between control and amygdalin-treated MRC-5 fibroblasts. Based on these observations, we concluded that amygdalin treatment offers a valuable option for the cancer treatment, causing inhibition of cell growth and down-regulation of telomerase activity in human cancer cell lines by increasing β-glucosidase activity. © 2015 Korean Society for Integrative Biology


Sung H.-J.,Gyeongsang National University | Ok S.-H.,Gyeongsang National University | Sohn J.-Y.,Gyeongnam science High School | Son Y.H.,Gyeongnam science High School | And 9 more authors.
Journal of Biomedicine and Biotechnology | Year: 2012

Aminoamide local anesthetics induce vasoconstriction in vivo and in vitro. The goals of this in vitro study were to investigate the potency of local anesthetic-induced vasoconstriction and to identify the physicochemical property (octanol/buffer partition coefficient, pKa, molecular weight, or potency) of local anesthetics that determines their potency in inducing isolated rat aortic ring contraction. Cumulative concentration-response curves to local anesthetics (levobupivacaine, ropivacaine, lidocaine, and mepivacaine) were obtained from isolated rat aorta. Regression analyses were performed to determine the relationship between the reported physicochemical properties of local anesthetics and the local anesthetic concentration that produced 50% (ED 50) of the local anesthetic-induced maximum vasoconstriction. We determined the order of potency (ED50) of vasoconstriction among local anesthetics to be levobupivacaine > ropivacaine > lidocaine > mepivacaine. The relative importance of the independent variables that affect the vasoconstriction potency is octanol/buffer partition coefficient > potency > pKa > molecular weight. The ED50 in endothelium-denuded aorta negatively correlated with the octanol/buffer partition coefficient of local anesthetics (r2 = 0.9563; P < 0.001). The potency of the vasoconstriction in the endothelium-denuded aorta induced by local anesthetics is determined primarily by lipid solubility and, in part, by other physicochemical properties including potency and pKa. © 2012 Hui-Jin Sung et al.


Ahn C.W.,Korea Basic Science Institute | Ha M.G.,Korea Basic Science Institute | Hong K.S.,Korea Basic Science Institute | Lee D.J.,Korea Electrotechnology Research Institute | And 8 more authors.
Defect and Diffusion Forum | Year: 2010

The surface conditions of LiFePO4 powder were modified by adding AlF3 and Al2O3 by using the sol-gel process to improve its electrochemical properties. The surface of LiFePO4 powders was partially covered with nano-sized AlF3 and Al 2O3, which is confirmed by using a transmission electron microscope image. The states of coated Al materials were examined by using X-ray photoelectron spectrometer results. The nano-sized AlF3- and Al 2O3-coated LiFePO4 powders showed no difference in the bulk structure compared with the pristine one. However, the AlF 3- and Al2O3-coating on LiFePO4 powders improved the overall electrochemical properties such as the discharge capacity, the cyclability, and the rate capability compared with those of a pure LiFePO4. Such enhancements were attributed to the presence of a stable AlF3 and Al2O3 layer which acts as an interfacial stabilizer on the surface of LiFePO4 powders. © (2010) Trans Tech Publications.


Hwang J.,Korea Astronomy and Space Science Institute | Choi K.,Korea Astronomy and Space Science Institute | Lee J.,Korea Astronomy and Space Science Institute | Park Y.-D.,Korea Astronomy and Space Science Institute | Ha D.-H.,Gyeongnam Science High School
Journal of Astronomy and Space Science | Year: 2011

Korea Astronomy and Space Science Institute researchers have installed and operated magnetometers at Mt. Bohyun Observatory to measure the Earth's magnetic field variations in South Korea. We, in 2007, installed a fluxgate magnetometer (RFP-523C) to measure H, D, and Z components of the geomagnetic field. In addition, in 2009, we installed a Overhauser proton sensor to measure the absolute total magnetic field F and a three-axis magneto-impedance sensor for spectrum analysis. Currently three types of magnetometer data have been accumulated. In this paper, we provide the preliminary and the first statistical analysis using the BOH magnetometer installed at Mt. Bohyun Observatory. By superposed analysis, we find that daily variations of H, D, and Z shows similar tendency, that is, about 30 minutes before the meridian (11:28) a minimum appears and the time after about 3 hours and 30 minutes (15:28) a maximum appears. Also, a quiet interval start time (19:06) is near the sunset time, and a quiet interval end time (06:40) is near the sunrise time. From the sunset to the sunrise, the value of H has a nearly constant interval, that is, the sun affects the changes in H values. Seasonal variations show similar dependences to the sun. Local time variations show that noon region has the biggest variations and midnight region has the smallest variations. We compare the correlations between geomagnetic variations and activity indices as we expect the geomagnetic variation would contain the effects of geomagnetic activity variations. As a result, the correlation coefficient between H and Dst is the highest (r = 0.947), and other AL, AE, AU index and showed a high correlation. Therefore, the effects of geomagnetic storms and geomagnetic substorms might contribute to the geomagnetic changes significantly. © The Korean Space Science Society.

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