Pohang, South Korea
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Yu R.,Northwest University, China | Yu R.,Pukyong National University | Noh H.M.,Pukyong National University | Moon B.K.,Pukyong National University | And 5 more authors.
Journal of Alloys and Compounds | Year: 2013

A novel series of Ba3La(PO4)3:xEu 3+ (0.01 ≤ x ≤ 1.00) phosphors was prepared by the convenient solidstate reaction. The structural and photoluminescent properties of the phosphors were carefully studied. The X-ray powder diffraction analysis confirmed the formation of the complete solid solutions between Ba 3La(PO4)3 and Ba3Eu(PO4) 3. The photoluminescence spectra showed that the samples had intense and prevailing red emissions at 610 nm belonging to the 5D 0 → 7F2 electric dipole transition. The optimum dopant concentration of Eu3+ ions in Ba3La(PO 4)3:xEu3+ was around 90 mol%, and the critical transfer distance of Eu3+ was calculated to be 8.4 Å. The quenching temperature for Ba3La0.10(PO4) 3:0.90Eu3+ was estimated to be above 500 K. Under 394 nm excitation, the quantum efficiency of Ba3La0.10(PO 4)3:0.90-Eu3+ was determined to be ~71%. Therefore, Eu3+-doped Ba3La(PO4)3 phosphors are potential red phosphors for NUV chip-based WLEDs and display devices. © 2013 Elsevier B.V. All rights reserved.


Park B.D.,Sungkyunkwan University | Kim T.G.,Sungkyunkwan University | Kim J.E.,Kaya University
Oncotarget | Year: 2016

Intensity-modulated radiation therapy (IMRT) provides the protection of the normal organs and a precise treatment plan through its optimization process. However, the final dose-volume histogram (DVH) obtained by this technique differs from the optimal DVH, owing to optimization convergence errors. Herein, intermediate dose calculation was applied to IMRT plans during the optimization process to solve these issues. Homogeneous and heterogeneous targets were delineated on a virtual phantom, and the final DVH for the target volume was assessed on the target coverage. The IMRT plans of 30 patients were established to evaluate the usefulness of intermediate dose calculation. The target coverage results were analogous in the three plans with homogeneous targets. Conversely, conformity indices (conformity index [CI], heterogeneity index [HI], and uniformity index [UI]) of plans with intermediate dose calculation were estimated to be more homogenous than plans without this option for heterogeneous targets (CI, 0.371 vs. 1.000; HI, 0.104 vs. 0.036; UI, 1.099 vs. 1.031 for Phantom B; and CI, 0.318 vs. 0.956; HI, 0.167 vs. 0.076; UI, 1.165 vs. 1.057 for Phantom C). In brain and prostate cancers, a slight difference between plans calculated with anisotropic analytical algorithm (AAA) was observed (HI, p = 0.043, UI, p = 0.043 for brain; HI, p = 0.042, UI, p = 0.043 for prostate). All target coverage indices were improved by intermediate dose calculation in lung cancer cases (p = 0.043). In conclusion, intermediate dose calculation in IMRT plans improves the target coverage in the target volume around heterogeneous materials. Moreover, the optimization time can be reduced.


Noh D.O.,Kaya University | Choi H.-S.,Korea University | Suh H.J.,Korea University
Process Biochemistry | Year: 2014

This work studied the effect of a sequential addition of substrate on tannase reaction for the increase of epigallocatechin (EGC) and gallic acid. The addition of 0.5-1% GTE increased the production of gallic acid during 2 h in a single tannase reaction, while the addition of more than 2% in GTE rather showed a decrease in gallic acid level with an increase of EGCG level compared with 1% GTE addition group, suggesting that GTE addition of 2% and over inhibits the reaction of tannase. Examination of sequential addition of 1% GTE on tannase reaction showed that second addition of 1% GTE at 2 h promoted tannase reaction by increasing production of gallic acid, but further addition (2 and 3 h) rather inhibited tannase reaction with lowered gallic acid and enhanced EGCG levels. This result showed that one additional treatment of 1% GTE during tannase reaction is effective in an increase of gallic acid production. Moreover, levels of degallated products including EGC, EC, and GC were increased by 7.3, 4.5, and 3.5-fold, respectively in sequential addition of GTE at 2 h. pH change derived from gallic acid production was not shown to related to tannase activity. Therefore, our study suggests that one sequential addition is a suitable process for desirable production of green tea extracts enriched in active components such as gallic acid and EGC. © 2013 Elsevier Ltd. All rights reserved.


Park D.-J.,Kaya University | Hwang Y.-I.,Dong - A University
Journal of Bodywork and Movement Therapies | Year: 2016

Background: We hypothesised that the balance of spastic chronic stroke patients is related to myofascial problems. We performed myofascial release (MFR) with a tennis ball on the affected limb, as suggested by Myers. Purpose: This study investigated the benefits of 8 weeks of MFR using a tennis ball on the balance of spastic patients. Methods: Eight stroke patients were enrolled voluntarily after providing informed consent. All subjects received 8-week interventions with MFR using a tennis ball three times per week. The patients were evaluated using the Berg Balance Scale (BBS) and Timed 'Up & Go' (TUG) test before and after 4 and 8 weeks of the intervention. Results: There were significant differences in the BBS scores (= 0.001). The TUG time decreased significantly at 4 and 8 weeks (= 0.034). Conclusion: Myofascial release appears to improve the balance of spastic chronic stroke patients; however, further studies should evaluate the effective of MFR on walking in stroke patients and determine the mechanism of the effect of MFR. © 2015 Elsevier Ltd.


Choi H.D.,Kaya University | Seo P.J.,Kaya University | Lee U.,Pukyong National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title compound, C 21H 21BrO 2S, the cyclohexyl ring adopts a chair conformation. The 4-bromophenyl ring makes a dihedral angle of 81.62(6)° with the mean plane of the benzofuran fragment. In the crystal, molecules are linked by weak C-H···O and C-H···π interactions. The crystal structure also exhibits a slipped π-π interaction between the furan rings of neighbouring molecules [centroid-centroid distances = 3.540(3) Å, interplanar distance = 3.481(3) Å and slippage = 0.644(3) Å].


Choi H.D.,Kaya University | Seo P.J.,Kaya University | Lee U.,Pukyong National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2014

In the title compound, C17H15FO3S, the dihedral angle between the mean planes of the benzofuran and 2-fluorophenyl rings is 87.61(4)Å. In the crystal, molecules are linked via pairs of C - H⋯π interactions into inversion-related dimers. These dimers are linked by C - H⋯O hydrogen bonds into supramolecular chains running along the a-axis direction. © 2014 CrossMark.


Choi H.D.,Kaya University | Lee U.,Pukyong National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2014

In the title compound, C17H15ClO3S, the dihedral angle between the planes of the benzofuran ring system [r.m.s. deviation = 0.008Å] and the 4-methylphenyl ring is 77.29(4)°. In the crystal, molecules are linked by π-π interactions between the benzene rings of neighbouring molecules [centroid-centroid distance = 3.847(2)Å] and between the benzene and furan rings of neighbouring molecules [centroid-centroid distance = 3.743(2)Å]. The molecules are stacked along the a-axis direction. In addition, pairs of C-H⋯O hydrogen bonds are observed between inversion-related dimers: these generate R 2 2(12) loops.


Choi H.D.,Kaya University | Lee U.,Pukyong National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2014

In the title compound, C15H10ClFO2S, the dihedral angle between the plane of the benzofuran ring system [r.m.s. deviation = 0.013 (1) Å] and that of the 3-fluorophenyl ring [r.m.s. deviation = 0.005 (1) Å] is 31.36 (5)°. In the crystal, molecules are linked by two different pairs of C - O hydrogen bonds, forming inversion dimers.


Choi H.D.,Kaya University | Lee U.,Pukyong National University
Acta Crystallographica Section E: Structure Reports Online | Year: 2014

In the title compound, C17H16O3S, the dihedral angle between the plane of the benzofuran ring system [r.m.s. deviation = 0.010 (1) A ] and that of the 3-methylphenyl ring is 79.09 (5)° Intramolecular C-H O hydrogen bonds are observed. In the crystal, molecules are connected into a chain along the caxis direction by two different pairs of inversion-generated interactions: C-H hydrogen bonds between the methyl groups and the benzene rings of the 3-methylphenyl fragments and π interactions between the benzene and furan rings of neighbouring molecules [centroid-centroid distance = 3.673 (2) A.


Sohn J.,Kaya University
Korean Journal of Materials Research | Year: 2013

In this study, intermediate-mixed powders were prepared by loading zirconia powders initially in a ball-mill jar and loading alumina powders afterward; the initial-mixed powders were produced by loading zirconia and alumina powders together in the ball-mill jar. The effect of such differences in mixing method on the mechanical properties was investigated. In intermediate-mixed powders, the volume fraction of large particles slightly increased and, simultaneously, zirconia particles formed agglomerates that, due to early ball-mill loading of the zirconia powders only, were more dispersed than were the initialmixed powders. For the intermediate-mixed powders, zirconia agglomerates were destroyed more quickly than were initialmixed powders, so the number of dispersed zirconia particles rose and the inhibitory effect of densification due to the addition of a second phase was more obvious. In the microstructure of intermediate-mixed powders, zirconia grains were homogeneously dispersed and grain growth by coalescence was found to occur with increasing sintering temperature. For the initial-mixed powders, large zirconia grains formed by localized early-densification on the inside contacts of some zirconia agglomerates were observed in the early stages of sintering. The intermediate-mixed powders had slightly lower hardness values as a whole but higher fracture toughness compared to that of the initial-mixed powders. © Materials Research Society of Korea.

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