• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.1-11
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• 2005

The study were to assess technical factors between the high score group and the low score group, from the subjects of 8 male national gymnasts, and to analyze the kinematical characteristic and main technical cause on technique of Kasamatsu movement on Vault. The result of this study is this. In case of horse contact time the high score group was swifter than low score group, and there was significant difference between the high score group and the low score group(<.01). On high score group the time of taking on from horse showed shorter than that of taking off from horse, while of the low score group the time of taking on the horse was similar to that of taking off from horse on the average. And in time of pre-flight the high score group on average the was 0.16sec shorter times than the low score group, and so there was significantly difference between groups(<.05). Also It is a characteristic that the high score group was short in horse contact time and longer in post-flight. In the horizontal distance of post-flight, the high score group was 0.11m longer than the low score group and there was significantly statistic difference between groups(<.05). In the vertical height of the cog in Post-flight's phrase, the high score group was 0.15m higher than the low score group and there was significantly statistic difference between groups(.<01). The horizontal velocity and vertical velocity in the event of taking on and off Beat board and Vault weren't significantly statistic differences between two groups. In the slow-down of average horizontal velocity during keeping contact with the beat board, the high score group was larger than the low score group. And in an increased average vertical velocity during keeping contact with the beat board, the high score group was even larger than the low score group. In the projectile angle of cog in taking off the beat board, 40.2deg., the angle of low score group and 39.5deg., the angle of high score group are nearly alike. In the projectile angle of cog in taking off the beat, the high score group showed 1.6Wt larger on average than the low score group. However the average reaction force on the board and Vault wasn't almost different between two groups, showed 0.3~0.6Wt larger in the high score group.

• Ocean and Polar Research
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• v.27 no.2
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• pp.197-203
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• 2005

Dimethylsulfide (DMS) is the most abundant form of volatile sulfurs in the ocean. Many biogeochemical studies have been conducted in the past several decades to unveil the processes driving the production, transformation and removal of DMS. They have shown that the Southern Ocean is an area with one of the highest levels of DMS concentrations during the austral summer in the global oceans. It has recently been observed that Antarctic krill, Euphausia superba, produces DMS and dissolved dimethyl-sulfoniopropionate (DMSP) in its gazing process. Copepods also produce DMS, and the potential production rates of DMS in the Southern Ocean by krill and copepods are estimated to be as much as $21{\mu}mol\;m^{-2}d^{-1}$ and $0.6{\mu}mol\;m^{-2}d^{-1}$, respectively. These production rates of zooplankton and the presence of phytoplanktot which have high DMSP contents in their cells, might facilitate in situ DMS production in the Southern Ocean.

• The Korean Journal of Ceramics
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• v.5 no.4
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• pp.379-385
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• 1999

Minute boehmite crystals with high aspect rations, which were hydrothermally synthesized from gibbsite in $Ba(OH)_2$ solution, occluded Ba with the Ba/Al molar ratio of about 0.03 in their interlayers. Their surface areas were about 14$\m^2$/g. The Ba-intercalated bohemite samples were partly used for producing $BaAl_{12}O){19}$ with low sinterability by externally supplementing $Ba(OH)_2$, and for forming transient aluminas. The surface area of $BaAl_{12}O){19}$ obtained by firing at $1500^{\circ}C$ for 3 h was 5.3$\m^2$/g, which was significantly lower than 12$\m^2$/g of the sol-gel origin. While a mixture ${\gamma}$-alumina and BaO is known to from $BaAl_{12}O){19}$ at $1200^{\circ}C$, solid state reaction between η-alumina transformed from the Ba-intercalated boehmite and BaO formed from $Ba(OH)_2$ deposited on the boehmite started above $1300^{\circ}C$. This suggests that large sized $Ba^{2+}$ ion occluded in η-alumina considerably suppresses the diffusion of $Al^{3+}$ ion. The surface area of the Ba-intercalated boehmite fired at $1400^{\circ}C$ for 3h was as high as 14$\m^2$/g indicative of its potential applicability to combustion catalysts. But it was decreased to 5.0$\m^2$/g after firing at $1500^{\circ}C$ for 3 h, accompanied by abrupt formations of $\alpha$-alumina and $BaAl_{12}O){19}$ as main products. The suppression of $\alpha$-alumina formation up to $1400^{\circ}C$ also suggests the significant blocking effect of $Ba^{2+}$ ion on the diffusion of the component ions.

• Korean Journal of Applied Biomechanics
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• v.16 no.1
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• pp.89-99
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• 2006

The study were to assess technical factors between the high score group and the low score group, from the subjects of 16 male national gymnasts, and to analyze the kinematical characteristic and main technical cause on technique of Akopian's 3D motion analysis of the male vaulting game in 2001 classification championship. The result of this study is this. There were not so much difference between the two groups in term; of the time of board contact, pre-flight, and total performance, but it takes shorter time when the players who are in the high point group take down the board, and they take long time for post-flight(p<.01). The high point group has a longer perpendicular distance in the moment of horse taking off, 0.05m on the average, than the low point group. The high point group shows 0.16m higher on the average than the other group in term; of the height of post-flight(p<.01). In the phase of board contact, the range of horizontal velocity at board take on were $7.66m/s{\sim}7.33m/s$, but there weren't significantly statistic differences between two groups. The hight score group were 0.68m/s faster than the low point group at the horizontal velocity at board take off event(<.05). About the average horizontal velocity of deceleration, AG1(-1.95m/s) reduces the speed more than AG2(-1.57m/s)(p<.05). And the hight score group were 0.37m/s faster than the low point group at the vertical velocity at horse take off event(<.05). When board taking off, the projectile angle of com were $38.7{\sim}37.8degree$ on the average. the comparative groups show almost same results. When horse taking off, the HPVy of the high point group were 37.6 degree which were a little higher than the low point group. The angular velocities of the players who takes on the horse with a right hand and then takes off with a left hand in the high point group were 14.97rad/sec, 10.82rad/sec in the low point group. However, the angular velocity of the players who takes on the horse with a left hand and then takes off on a right hand with the high point group were 14.97rad/sec, 15.56rad/sec in the low point group.