• Journal of Korean Medicine Rehabilitation
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• v.19 no.2
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• pp.289-302
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• 2009

Objectives : This study was performed in order to investigate the relation of body composition analysis and radiological parameter(lumbosacral angle, lumbar lordortic angle, lumbar gravity line). Methods : This study was carried out with the data from comprehensive medical testing. 75 subject aged 20-59 performed the segmental bioelectrical impedance analysis, questionnaire. And lumbosacral angle, lumbar lordortic angle and lumbar gravity line were measured in the standing position x-ray. Then we analyzed the data. Results : Low back pain(LBP) prevalence in high obesity index(Body Mass Index(BMI), Percentage of Body Fat(PBF), Waist Hip Ratio(WHR)) group was higher than LBP prevalence in normal obesity index group(p<0.01). In LBP group, lumbosacral angle, lumbar lordortic angle were significantly lager than Non-LBP group(p<0.001). And 75% of LBP group indicated abnormal lumbar gravity line ratio(0.67 < Normal lumbar gravity line ratio <1.00). When it comes to analyze relation between obesity index and radiological parameter, no-significant change was seen. Conclusions : This study carried as following research after the study on relation of obesity, LBP and trunk muscle strength. Results from this investigation showed positive correlation between obesity and LBP prevalence. But obesity index didn't indicate significant correlation with structural changes of lumbar vertebrae. When considering prior research, trunk muscle strength changes were more related to LBP prevelence in obese people. This results are expected to explain causes of LBP in obese group.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.3
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• pp.282-292
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• 2015

Seeds of colored rice generally have high anthocyanin and flavonoid content but some cultivars have low seed germination rate. This defect poses unstable seedling establishment in nursery bed. The seed gravity variations of 10 colored rice varieties and its effect on germination, seed soaking duration and their optimum seeding rates for seedling raising in machine transplanting were investigated in the experiment. Based on seed gravity distribution of the 7 black- and 3 red-colored rice varieties at three levels of seed gravity (1.0<, 1.0~1.06, 1.06>), the black colored seeds such as Josaengheugchal and Sinmyungheugchal had high amount of specific gravity of below 1.0 ranging from 86~ 96%, while they had only 3~13% of seeds in specific gravity above 1.06. Sintoheugmi, Heugjinju, Heugnam, Heugkwang had various mass of seeds, showing 29~44% for specific gravity of below 1.0, 24~39% for 1.0~1.06 and 25~45% for above 1.06. On the other hand, the red colored rice such as Hongjinju, Jeogjinju and Geonkanghongmi had high percentage of specific gravity of above 1.06 with 84~86% while they had only 9~12% of specific gravity below 1.0 similar to Ilmibyeo of noncolored rice. The black colored seed generally showed low germination percentage, slow germination speed and long mean germination time, and low water absorption rate as compared with seed of the red colored rice which was similar to those of Ilmibyeo used as a control cultivar. The black colored seeds took 2~4 days longer seed soaking duration than the red colored rice before germination. This was related to high seed amount of specific gravity below 1.0 in black colored rices. The high amount of seed gravity above 1.06 in the colored rice seeds was positively correlated with percentage of germination, germination speed and mean germination time, ripened grain ratio and water absorption. Seed gravity distribution effect were less pronounced between back- and red- colored seeds in seedling emergence. The black colored rice has slightly lower normal seedling emergence rate than the red colored rice and Ilmibyeo in the seedbed soil due to high percentage of ungerminated seed. Normal seedling emergence rate of the black colored rice in the seedbed was 75.2~82.2% for 10-day old seedling and 85.3~ 90.9% for 30-day old seedling which was lower by 4.5~ 8.0% and 0~3.3%, respectively, than the red colored rice. Based on the normal seedling number per tray of Ilmibyeo for seeding rate of 10-day and 30-day old seedlings, the recommended seeding rate of black colored rice is 200~ 220g seeds for the 10-day old seedling and 110~130g for the 30-day old seedling in transplanting rice while the seeding rate of the red colored rice was 220g seeds for the 10-day old seedling and 130g for the 30-day old seedling.

• Journal of the Korean Society of Safety
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• v.17 no.2
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• pp.112-117
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• 2002

The effects of shield gas on the structure of methane-air nonpremixed counterflow flames were numerically investigated. The near extinction flame of a low global strain rate 20 $s^{-1}$ of 19% methane diluted by 81% nitrogen by volume and undiluted air was computed. The flame shape, centerline temperature and axial velocity profiles were compared for different velocity of the shield gas and with and without the shield gas. The effects of the velocity of the shield gas were negligible for $V_{S}/V_{F}{\leq}2$ in normal gravity. Under normal gravity conditions, the flame shape and its position with the shield gas were different from those of the flame without the shield gas, whereas no discernible effects of the shield gas along the centerline were observed in zero gravity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.4
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• pp.172-183
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• 2009

For the effects of the nonlinear temperature profiles and reduced-gravity conditions we conduct a two-dimensional numerical modeling and simulations on the physical vapor transport processes of $Hg_2Cl_2-Xe$ system in the horizontal orientation position. Our results reveal that: (1) A decrease in aspect ratio from 5 to 2 leads to an increasingly nonuniform interfacial distribution and enhances the growth rate by one-order magnitude for normal gravity and linear wall temperature conditions. (2) Increasing the molecular weight of component B, Xenon results in a reduction in the effect of solutal convection. (3) The effect of aspect ratio affects the interfacial growth rates significantly under normal gravity condition rather than under reduced gravitational environments. (4) The transition from the convection-dominated regime to the diffusion-dominated regime ranges arises near at 0.1g$_0$ for operation conditions under consideration in this study.

• Journal of Korea Foundry Society
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• v.19 no.1
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• pp.47-53
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• 1999

Squeeze casting process has been used in the field of a commercial manufacturing method, in which metal is enforcedly solidified under pressure enough to prevent the cast defects such as either gas porosity or shrinkage defect. In this paper, to clarify the relationship between applied pressures and macro ${\cdot}$ microstructural behaviors in gravity and direct squeeze casts, specimens were cast by various squeezing pressures during solidification of 7000 series Al wrought alloy in the metal die designed specially. The applied pressures used in this study were 0, 25, 50, and 75 MPa. The microstructural morphologies of squeeze cast were more fine and dense with increasing the applied pressures, because of the greater solidification rate of billet resulting from the applied pressure. A normal segregation phenomenon of an increasing in amount of eutectics towards the center of the billet was observed for squeeze casts, whereas gravity cast showed an inverse segregation phenomenon of an increasing in amount of eutectics towards the edge in the billet. This change in segregation pattern which is normal or inverse is due to a higher radial temperature gradient and reduced time in the semi solid state for squeeze casting.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.2 no.2
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• pp.17-32
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• 2007

Objectives : The lumbosacral joint is unstable area from an anatomical viewpoint, while it is also a very mobile area in ordinary life, so that clinically major causes of low back pain originate in this joint. The purpose of this study is to assess the difference of the Ferguson's angles, Lumbar gravity lines, Lumbar lordotic angles among Herniated of Intervertebral Disc(HIVD) patients. Methods : We analyzed the lateral view of lumbar spine checked at erect position on 88 patients who had been diagnosed as HIVD by Magnetic Resonance Imaging(MRI). We investigated the Ferguson's angle, Lumbar gravity line, Lumbar lordotic angle on X-ray film. Results and Conclusions : In the acute lumbago group the Ferguson's angle had a tendency to decrease, while in the chronic group it had a tendency to increase. In the acute lumbago group the Lumbar gravity line fell in front of the normal range(sacrum), while in the chronic group it fell behind the normal range(sacrum). In the acute lumbago group the Lumbar lordotic angle usually decreased, while in the chronic group it increased. The Ferguson's angle and the Lumbar gravity line, the Ferguson's angle and the Lumbar lordotic angle, the Lumbar gravity line and Lumbar lordotic angle each had a positive realtionship. The Ferguson's angle, the Lumbar gravity line and the Lumbar lordotic angle was less influenced by the level of HIVD and was more influenced by how long the patient had the pain. The correlationship between each factor was less in the chronic lumbago group than the acute group. In the chronic lumbago group the instability of the lumbosacral joint increased, while in the acute group the compression of the weight on the sacrum increased.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.29-35
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• 2012

Special attention in the role of convection in vapor crystal growth has been paid since some single crystals under high gravity acceleration of $10g_0$ appear considerably larger than those under normal gravity acceleration ($1g_0$). With increasing the gravity acceleration from $1g_0$ up to $10g_0$, the total molar flux for ${\Delta}T$ = 30 K increases by a factor of 4, while for ${\Delta}T$ = 90, by a factor of 3. The maximum molar fluxes for three different gravity levels of $1g_0$, $4g_0$ and $10g_0$, appear approximately in the neighborhood of y = 0.5 cm, and the molar fluxes show asymmetrical patterns, which indicate the occurrence of either one single or more than one convective cell. As the gravitational level is enhanced form $1g_0$ up to $10g_0$, the intensity of convection is increased significantly through the maximum molar fluxes for ${\Delta}T$ = 30 K and 90 K. At $10g_0$, the maximum total molar flux is nearly invariant for for ${\Delta}T$ = 30 K and 90 K. The total molar flux increases with increasing the gravity acceleration, for $1g_0{\leq}g_y{\leq}10g_0$, and decreases with increasing the partial pressure of component B, a noble gas called as Kr (Krypton), $P_B$. The ${{\mid}U{\mid}}_{max}$ is directly proportional to the gravity acceleration for 20 Torr $P_B{\leq}300$ Torr. As the partial pressure of $P_B$ (Torr) decreases from 300 Torr to 20 Torr, the slopes of the ${{\mid}U{\mid}}_{max}s$ versus the gravity accelerations increase from 0.29 sec to 0.54 sec, i.e. by a factor of 2. The total molar flux of $Hg_2Cl_2$ is first order exponentially decayed with increasing the partial pressure of component B, $P_B$ (Torr) from 20 Torr up to 300 Torr.

• Journal of the Korean Society of Combustion
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• v.2 no.1
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• pp.29-38
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• 1997

In this study, the experimental and numerical investigations of the ignition of methane-air mixtures by a electrically heated wire have been carried out. In order to define the initial condition and make the analysis simple, the following control unit was developed; which heats the wire to the setting temperature in a very short time, and maintains the wire temperature constant until ignition. Experiments with the feedback control have been performed using nickel and platinum wires in normal gravity and microgravity. From experimental results, ignition temperatures in normal gravity are higher than those in microgravity, however, the dependences of ignition temperature on equivalence ratio are not affected by natural convection. Numerical calculations, including catalytic reaction for platinum, have been performed to analyze the experimental results in microgravity. Numerical results show that reactants near platinum wire are consumed by catalytic reaction, therefore, the higher temperature is needed to ignite the mixture with platinum wire.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.177-184
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• 2003

Stabilization mechanism of lifted flame in the near field of coflow jets has been investigated experimentally and numerically for methane fuel diluted with nitrogen. Lifted flames were observed only in the near field of coflow jets until blowout occurred in the normal gravity condition. To elucidate the stabilization mechanism for the stationary lifted flames in the near field of coflow jets for the diluted methane having the Schmidt number smaller than unity, the behaviors of the stationary lifted flame in microgravity and unsteady propagation phenomena were investigated numerically at various conditions of jet velocity. It has been founded that the buoyancy plays an important role for flame stabilization of lifted flame in normal gravity and the stabilization mechanism is due to the significant variation of the propagation speed of lifted flame edge compared to the local flow velocity at the edge.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.425-427
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• 2006

It is quite difficult to transfer the National Height System 1985 to the island in China. In the study, one feasible and alternative way, which measures synchronally the tide variation at the island and the coast , is firstly introduced. Then, a new method is proposed. This new method combines GPS technique and Quasi-Geoid Determination technique (GQGD). It needs gravity data, GPS data, leveling data and DEM data, together with complex calculation method and the Earth gravity model. After describing the mathematical model and presenting the calculational steps, one experiment has been shown that this method is valid and can achieve accuracy up to 5 cm for the normal height, compared with the results both from the tidal observation and height approximation. Some suggestion is also given in the end.