Pohang, South Korea
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Lee S.-K.,Kaya University
Journal of Distribution Science | Year: 2016

Purpose - This study investigates the improvement of rationalization of distribution structure in Korean diamond market. It also explores the international distribution of diamond and how the distribution of Korean diamond market system was improved. This study also for providing the evaluation method in case of purchasing diamond on the consumers. Research Design, Data, and Methodology - The research investigates how international diamond distribution market has been changed since 1933 by De Beers. The international Diamond rough stone has been deregulated in supply and demand by Debeers since July, 2000, therefore, the price maintenance policy of diamond market also has been changed. In the short term, the diamond price in market has been down, whereas, in the long term, the market share of Debeers has affected the high quality of diamond price in world market. Before 1985, both G color and VVS1 clarity were used as the level of percentages in the diamond certificate of authenticity in Korea. But, after 1985, the diamond certificate of authenticity uses Diamond Grading Report. Results - Between the 1970's and 1980's, Debeers had controlled about 80 percentages of international diamond supply market. But, Debeers share in diamond market fell by 60 percentages in 2000's. Debeers supplied 31%(4390 carets) of international diamond supply and 41%(39 billion dollars) in 2003. However, Debeers shares 50% of market shares in the diamond supply market by Alosa in Russia. In Korea, the diamond grading report system has been used since 1985. But, the diamond grading report system has price bubbles and much irrational parts in grading system methods. Conclusions - 4C, the grading system of diamond, is a method for comparing and evaluating diamond objectively. Diamond is graded according to its color, cut, clarity, and carat. The price of diamond is determined based on its each item. Consumers purchase diamond for the purpose of investment and wearing. In terms of investment, it is recommended to purchase diamond with color of D grade, cut with Excellent or Very Good Cut grade, Clarity of FL or IF, and more than 3 carat. As for wearing purpose, it is highly recommended for diamond to have color of F or G grade, cut of Excellent or Very Good Cut, clarity of VS2 or SI1, and more than 1 carat Before 2000, Central Selling Organization(CSO) distributed about 80 percentages rough diamond to world market exclusively by purchase, classification, assessment, and sales. After 2000, Dbeers diamond company looses slowly market shares, while Almosa diamond company etc. in Russia are taking over world market shares more and more. Debeers market shares have been falling over the years, and the international diamond markets are gradually growing by other international diamond companies. But, there is no change in Korean diamond market after 1980's. Korean diamond distribution needs to follow international level of Diamond Grading System. By using different grading systems with different panel members, Korean diamond grading system needs to follow international perfect grading systems to grow diamond markets and maintain within top 10 diamond markets countries.


Cho S.-H.,Kaya University | Kim S.-H.,Kaya University
Journal of Physical Therapy Science | Year: 2016

Purpose] This research explored the positive effects of self-myofascial release on hamstring muscular flexibility and proprioception and investigated the effectiveness of the stretch combined with therapeutic ultrasound. [Subjects and Methods] This study included 30 healthy university students with no history of pain in the Achilles tendon or hamstring within the recent 6 months. Each participant completed two experiments. In the first experiment (MS), they completed self-myofascial stretching using a foam roller for 7 days. In the second experiment (MSU), the same participants performed the self-myofascial stretching after the 15-minute application of ultrasound. This study involved a pre- and post-test on hamstring muscle flexibility and hip joint proprioception. [Results] The use of self-myofascial stretching in the MS experiment had a significant effect on hamstring muscle flexibility and hip joint proprioception. However, the addition of ultrasound in the MSU experiment had no additive effect. [Conclusion] Self-myofascial stretching immediately increased hamstring muscle flexibility and improved hip joint proprioception, but the addition of pre-stretch ultra sound provided no further benefit. © 2016 The Society of Physical Therapy Science.


Park D.-J.,Kaya University
Journal of Physical Therapy Science | Year: 2016

[Purpose] This study investigated the effects of visual stimulus using central and peripheral vision fields on postural control. [Subjects and Methods] The subjects consisted of 40 young adult volunteers (15 males, 25 females) who had been informed of the study purpose and procedure. The subjects were randomly divided into four groups of differing visual stimulus. Each group was given visual intervention in a standing position for 3 minutes. Postural control was evaluated before and after visual intervention. [Results] The results of the functional reach test and body sway test showed significant differences among the four groups. [Conclusion] The two-way peripheral vision-field group showed significantly more body sway after visual intervention than the other three groups. This finding may suggest two-way peripheral vision field is a more effective visual stimulus for training postural control and balance. © 2016 The Society of Physical Therapy Science.


Park Y.-J.,Sehan University | Lee C.-Y.,Kaya University
Journal of Physical Therapy Science | Year: 2016

[Purpose] The aim of this study was to examine the effects of community-based rehabilitation program in chronic stroke patients. [Subjects and Methods] Eleven subjects received community-based rehabilitation program ten times for ten months. The main outcome measures were the Modified Barthel Index score for activities of daily living and the Korean Mini-Mental State Examination score for cognition. [Results] The results of the study demonstrated that the community-based rehabilitation program improved activities of daily living performance and cognition significantly. [Conclusion] Based on the study results, the community-based rehabilitation program is an effective method for improving activities of daily living performance and cognitive function in elderly patients with chronic stroke. © 2016 The Society of Physical Therapy Science.


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.


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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