• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.82-89
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• 2005

This study was performed to investigate the behavior and spatial distribution of fuel mixtures with different wall angle and diameter of piston cavity in a DI gasoline engine. The spatial distribution of fuel mixtures after impingement of the spray against a piston cavity is one of the most important. factors for the stratification of fuel mixture. Thus, it is informative to understand in detail the behavior and spatial distribution of fuel mixtures after impingement in the cavity. Two dimensional spray fluorescence images of liquid and vapor phase were acquired to analyze the behavior and distribution of fuel mixtures inside cylinder by exciplex fluorescence method. The exciplex system of fluorobenzene/DEMA in non-fluorescing base fuel of hexane was employed. Cavity wall angle was defined as an exterior angle of piston cavity. Wall angles of the piston cavity were set to 30, 60 and 90 degrees, respectively. The spray impinges on the cavity and diffuses along the cavity wall by its momentum. In the case of 30 degrees, the rolling-up moved from the impinging location to the round and fuel-rich mixture distributed at periphery of cylinder. In the case of 60 and 90 degrees, the rolling-up recircurated in the cavity and fuel mixtures concentrated at center region. High concentrated fuel vapor phase was observed in the cavity with 90 degrees. From. present study, it was found that the desirable cavity wall angle with cavity diameter for stratification in a Dl gasoline engine was demonstrated.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.4 no.2
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• pp.40-45
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• 2008

There exist many types of pipe and component fatigue through vibrations, thermal fatigues or shifting. In some cases of thermal stratification/thermal fatigue, pipes & components are receiving thermal stress by means of material expansion and shrinkage by continuous thermal repetitive variation. Small cracks initially occur on the inside surface by thermal stress. These cracks grow in depth the pipe wall and finally come to a rupture. Pipe parts of susceptibility to thermal stratification and thermal fatigue are now being examined by conventional UT(ultrasonic test) as volumetric examination. It is difficult to fully satisfy the code & standards requirements because 3" weldolet weldments of RCS 16" pipe to 3" branch connection lines have complex structural shape. To solve the problems of conventional UT examination, we made a realistic mock-up and UT calibration block. We performed a simulation of phased array UT utilizing CIVA as NDE(Non-Destructive Examination) simulation software. Also we designed phased array UT transducer and wedge, optimal frequency by using simulation data. We performed phased array UT experiment through mock-up including artificial flaws(notch). The phased array UT technique is finally developed to improve the reliability of ultrasonic test at RCS 16" pipe to 3" branch connection weld.

• Solar Energy
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• v.16 no.2
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• pp.65-77
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• 1996

The operating thermal chracteristics of direct contact liquid-ice heat exchanger was experimentally investigated. In this paper, The effects of Ice Packing Factor(IPF), the inlet temperature and the flow rate of Heat Transfer Fluid(HTF) were stuided in the liquid-ice heat exchanger. Thermal stratification in liquid-ice heat exchanger was established clearly and faster at the higher inlet temperature and flow rate of HTF. At the end of melting of the lower flow rate is cleared the thermal stratification in liquid-ice heat exchanger. The temperature stratification is long with higher value of IPF of liquid-ice heat exchanger. The mean temperature of liquid-ice storage was changed rapidly with increasing flow rate and inlet temperature of HTF. The gradiant of ratio of total energy to latent energy was found higher with increasing inlet temperature and flow rate.

• The Research Journal of the Costume Culture
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• v.8 no.5
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• pp.771-784
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• 2000

The purpose of this study was to investigate the casual relationships of self-monitoring, face satisfaction, and demographic variables on the purchasing behavior and use of cosmetics of women. Samples wre 479 women in their 20's to 50's in Seoul, Korea. Three factors of the purchase criteria of cosmetics derived by factor analysis : F.1 'intrinsic trait', F.2 'sales promotion and fashion', F.3 'economy. Women high in self-monitor purchased and used cosmetics more than those low in self-monitor. There were significant relationships between the purchasing behavior and use of cosmetics and age, education, and social stratification. Women in their 20's and 30's perceived purchase criteria associated with intrinsic trait such as color and becomingness as more important, 20's sales promotion and fashion, women with less education perceived economy more than did the others. Upper class women showed more concern for intrinsic trait such as quality and color of cosmetics than did lower class. Social stratification, age, self-monitoring, and education had a direct effect on the degree of cosmetics purchase. Self-monitoring and education had a direct effect on the degree of cosmetics use. Age, education, social stratification, and face satisfaction had an indirect effect on the degree of cosmetics purchase and use. The causal relationship of self-monitoring on the use of coloring cosmetics was stronger than the connection between self-monitoring and total cosmetics. The present findings provide that personal trait associated with self-monitoring of women is important variable in understanding of the purchasing behavior and use of cosmetics.

• Journal of Ginseng Research
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• v.20 no.3
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• pp.325-330
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• 1996

Dynamic parameters of physiology including embryo ratio (ER), embryo length to endosperm length, dry weight ratio between embryo and endosperm (DWR) and respiration rate (RR) in American send (Panax quinquefolium L.) seed were investigated. According to the changes of ER during seed stratification, the duration of embryo afterripening could be divided into three stages as \circled1 embryo slow growth stage (ESGS), ER increased from 7.31% to 20.48% (0.16% day-1): \circled2 embryo rapid growth stage (ERGS), ER increased to 80.98% (0.61% day-1) (75G5+ ERGS=morphological afterripening stage (MP,5)) and \circled3pysiological afterripening stage (PAS), ER Increased to 88.50% (0.094 day-1) only. DWR Increased slowly from 0.20% to 2.76clp (0.016% day-1) in MAS and rapidly to 8.81% (0.061% day-1) in PAS. The RR correlated significantly with ER as well (r=0.8934 > rot, 0.6610). The steep increment of both DWR and RR in PAS indicated that the PAS was not a static stage although the ER was not changed too much. All of these may provide some information for understanding the dormancy mechanisms of American sting seed.

• Korean Journal of Medicinal Crop Science
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• v.2 no.1
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• pp.32-37
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• 1994

This experiment was conducted to obtain the basic information for the increase ofgermination percent by the seed diameter, specific gravity, different grain filling period and stratification in Bupleurum falcatum seeds. The seed size of B.falcatum ranged from 2.0 to 3.9mm in diameter, The large seed showed the higher germinability, The optimum specific gravity of salt selection for seed screening was 1.05 resulting in screening out seeds with high germinability over 70%.The seeds needed grain filling period for 60 days or longer after flowering to keep high germinability The optimum period of stratification treatment to promote seed germination was about 80 days.

• Korean Journal of Medicinal Crop Science
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• v.1 no.2
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• pp.104-108
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• 1993

This experiment was conducted to obtain the basic information for the increase ofgermination percent by the treatment of stratification, soaking and $Gibberellin(GA_3)$ in Angelica gigas Seeds caltivated in 1989. The germination percent was increased by 30% with stratification, and the effect of low temperature did not differ significantly. The optimum soaking temperature and periods were found to be 4days at $20^{\circ}C\;and\;6dys\;l0^{\circ}C$ of water temperature. When exchanged water every day during soaking period, inhibitors were more extracted than non-exchange one. The exogenous application of $GA_3$ also increased germination percent about 20% campared with control, and the reasonable level was 2ppm in soaked seed and 5ppm in non-soaked seed.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.6
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• pp.419-423
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• 2015

The flowing caused by artificial upwelling structure occurs ascending water flowing and vortex of rear side. In this moment, plentiful nutrient in the bottom water moves to the surface of the water and makes those plankton and fishing ecology promoted so that the fishing productivity can be enhanced. In this study, the changes of the upwelling flowing is included in consideration of the conditions of stratification by using CFD. In the conclusion, the closer upwelling effect is from the artificial upwelling structure, the better effectiveness comes out. Regardless of the conditions of stratification, only the upwelling feature from the bottom to the surface was shown up. But considering the conditions of stratification, the repeated flowing feature between upwelling and downwelling was verified.

• Korean Journal of Medicinal Crop Science
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• v.25 no.4
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• pp.209-216
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• 2017

Background: Dehisced ginseng seeds need to be stored at cold temperatures for around 3 months to break their physiological dormancy, and thus, to aid in gemination. In the presence of high moisture in such an environment, seed spoilage and pre-germination may lower seed quality and productivity. To improve seed quality during cold-stratification, the effects of seed dehydration and temperature were tested. Methods and Results: In early December, dehisced ginseng seeds were dehydrated at 4 different levels and stored at $2^{\circ}C$ $-2^{\circ}C$, and $-20^{\circ}C$ for 3 months. Germination was carried out on the filter papers moistened with distilled water; emergence of root, shoot, and seed spoilage were assessed. Seed viability was examined by the tetrazolium test. More than 90% of the seeds stored at $2^{\circ}C$ and $-2^{\circ}C$ without drying or endocarp dehydration germinated, but seeds that were dehydrated to have a moisture content (MC) below 31% showed poor germination and lost their viability. In addition, the seeds stored at $-20^{\circ}C$ failed to show effective germination. Conclusions: Seed storage after endocarp dehydration might help to improve seed quality and increase seedling's ability to stand during the spring-sowing of ginseng.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.147-151
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• 2008

In Southern Sea of Korea, there are upwelling area where artificial seamount were built and the environment variations (temperature, salinity, nutrient and current) of before and after built seamount were observed between 2002 and 2007. In 2002, before the seamount was built, there had stratification at 20-30m. And in 2007, seamount was built, stratification of the seamount at the front and back of it were changed by 10-40 m and 20-30 m, respectively. To know the reason of this results, we used temperature and salinity using Brunt-Vaisala Frequency and horizontal current using vertical shear and relative vorticity. They showed upwelling was mainly reason that changed the ocean environment.