• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.237-243
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• 2010

In this study, the effect of the shape of a pintle(obstacle) on thrust-modulation performance and drag in a pintle rocket was investigated by a cold flow test and by computational fluid dynamics. Pintle movement caused a monotonic increase in the chamber pressure. Thrust generated by the pressure distribution on the pintle body was linearly changed to the chamber pressure, and this thrust was greater than that generated by the nozzle-wall pressure distribution. Because the shock pattern in the nozzle changes with the shape of the pintle body and pressure ratio, the thrust generated by the nozzle-wall pressure is not directly affected by chamber pressure. The drag due to the pintle(obstacle) can be minimized for a fully linear pintle shape, regardless of chamber pressure.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.145-149
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• 2011

We studied any variations of skin mucus cells of Misgurnus mizolepis caused by inducing a great change of water temperature including high temperature- and low temperature-adapted groups and then compared them with a control group of normal water condition. The high temperature-adapted group showed no significant different in size and number of the mucus cell (P>0.01), whereas in the low temperature-adapted group, the surface area of mucus cell layer and shape of its mucus cell, and the number of mucus cell remarkably increased in all the skin regions of dorsum, lateral region and occiput (P<0.01). Returned to the same condition as the control group, the low temperature-adapted groups showed the same features that appear in the normal water condition (P<0.01). Based on these results, the skin mucus cells of M. mizolepis seems to be very sensitive to cold water temperature and therefore they may play a key role in assessment of its environmental conditions.

• Korean Journal of Acupuncture
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• v.23 no.3
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• pp.17-27
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• 2006

Objectives : This study is aimed to search for the effective application of the Sa-Am acupuncture(舍岩鍼法) for the treatment of diarrhea. Methods : The classification and the treatment for diarrhea in ${\ll}$Sa-Am-Do-In-Chim-Gu-Yo-Kyul(舍岩道人鍼灸要訣)${\gg}$ was compared with those of ${\ll}$Dong-Eui-Bo-Kham(東醫寶鑑)${\gg}$ and ${\ll}$Chim-Gu-Dae-Sung(鍼灸大成)${\gg}$ Results & Conclusions : In ${\ll}$Dong-Eui-Bo-Kham(東醫寶鑑)${\gg}$, diarrhrea was classified into 20 classes and mainly treated with herbal medicine and additionally with acupuncture treatment. Ashi (nearby) points in lower abdomen and sacral region were often used as well as the points on Spleen meridian(SP) and Stomach meridian(ST) to treat diarrhea in ${\ll}$Chim-Gu-Dae-Sung(鍼灸大成)${\gg}$ According to ${\ll}$Sa-Am-Do-In-Chim-Gu-Yo-Kyul(舍岩道人鍼灸要訣)${\gg}$, Diarrhrea was classified into 6 classes; wet diarrhrea (濡泄; kidney damage), abrupt diarrhrea (暴泄; spleen damage), damp diarrhrea (濕泄; stomach damage), fire diarrhrea (火泄; heart dryness), ki(qi) diarrhrea (氣泄; lung damage) and cold diarrhrea (冷泄; liver damage). Sa-Am acupuncture seems to be applied on the basis of more precise diagnoses of organs and meridians and provide with more fundamental treatments in comparison with classical acupuncture.

• Korean Journal of Materials Research
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• v.26 no.3
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• pp.154-159
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• 2016

A roll-bonding process was applied to fabricate an AA1050/AZ91/AA1050 laminate complex sheet. Two AA1050 and one AZ91 magnesium sheets of 2 mm thickness, 30 mm width and 200 mm length were stacked up after surface treatment that included degreasing and wire brushing; material was then reduced to a thickness of 3 mm by one-pass cold rolling. The laminate sheet bonded by the rolling was further reduced to 2 mm in thickness by conventional rolling. The rolling was performed at 623K without lubricant using a 2-high mill with a roll diameter of 210 mm. The rolling speed was 15.9 m/min. The AA1050/AZ91/AA1050 laminate complex sheet fabricated by roll bonding was then annealed at 373~573K for 0.5h. The microstructure of the complex sheets was revealed by electron back scatter diffraction (EBSD) measurement; the mechanical properties were investigated by tensile testing and hardness testing. The strength of the complex sheet was found to increase by 11 % and the tensile elongation decreased by 7%, compared to those values of the starting material. In addition, the hardness of the AZ91 Mg region was slightly higher than those of the AA1050 regions. Both AA1050 and AZ91 showed a typical deformation structure in which the grains were elongated in the rolling direction; however, the mis-orientation distribution of grain boundaries varied greatly between the two materials.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.117.1-117.1
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• 2012

Energetic neutral atoms (ENAs) are emitted by charge exchange collisions between energetic ions and cold neutral atoms. ENAs can be used as an alternative measure of the energetic ions in the source region because they maintain the energy and pitch angle of the source energetic ions. In the present study we present simulation results of the ENA emissions during a magnetic storm to be measured by the STEIN instrument onboard the CINEMA/TRIO satellites. The CINEMA/TRIO mission consists of three identical cubesats with low-altitude orbits. The STEIN instrument onboard each cubesat can measure ENAs with energies from ~4 keV to ~20 keV as well as suprathermal electrons and ions. The measurement of ENA emissions from ring current by STEIN is simulated using the models for energetic ring current ions and geocoronal neutral atoms. Especially we will discuss about the energy spectrum of the ENAs and the effect of transient variations of the ring current.

• Korean Journal of Clinical Pharmacy
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• v.20 no.1
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• pp.72-77
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• 2010

The objective of this study was to find out guardians' understanding on the antibiotic use for their children under elementary school age. Survey analysis was performed on 671 questionnaire response sheets from the guardians for children ($\leq$13 years old) attending daycare centers, kindergartens, or elementary schools located in eastern part and vicinity of Seoul, Korea. Result showed that majority of the guardians did not follow right direction for the use of antibiotic medications. About 80% of the guardians discontinued or reduced dosage of the antibiotic medications if symptoms relieved, and about 66% of them administered the drug always after meal although interval was not consistent. Furthermore, only one-fifth of the guardians understood right indication of antibiotic medications that it is of no use to take antibiotics for the treatment of common cold. About 65% of the guardians participated in this study responded that they received drug information for antibiotic medications from doctors or pharmacists. However, in terms of knowledge score regarding antibiotic drug use, their score was significantly lower than that of guardians who received the information from internet or mass media. This result suggests that patients counsel is not efficiently being practiced among healthcare professionals in the region surveyed in this study. Therefore, in conclusion, it appears that community pharmacists need to be more interactive in patients counsel when they dispense antibiotic medications.

• Journal of the Korean earth science society
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• v.39 no.5
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• pp.403-418
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• 2018

This study conducted synoptic and mesoscale analyses to understand the cause of Japan Tsukuba tornado development, which occurred at 0340 UTC 6 May 2012. Prior to the tornado occurrence, there was a circular jet stream over Japan, and the surface was moist due to overnight precipitation. The circular jet stream brought cold and dry air to the upper-level atmosphere which let strong solar radiation heat the ground with clearing of sky cover. A tornadic supercell developed in the area of potentially unstable atmosphere. Sounding data at Tateno showed a capping inversion at 900 hPa at 0000 UTC 6 May. Strong insolation in early morning hours and removal of the inversion instigated vigorous updraft with rotation due to vertical shear in the upper-level atmosphere. This caused multiple tornadoes to occur from 0220 to 0340 UTC 6 May 2012. When comparing Tateno's climatological temperature and dew-point temperature profile on the day of event, the mid-level atmosphere was moister than typical sounding in the region. This study showed that tornado development in Tsukuba was caused by a combination of (a) topography and potential vorticity anomaly, which increased vorticity over the Kanto Plain; (b) vertical shear, which produced horizontal vortex line; and c) thermal instability, which triggered supercell and tilted the vortex line in the vertical.

• Journal of Korean Society of Rural Planning
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• v.18 no.3
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• pp.103-110
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• 2012

This study aims to find out the geographical distribution, the physical structure and characteristic of Gudle-jang Paddy-field in Cheongsando. On the basis of this study, the potential value and the assignment for the preservation of Gudle-jang Paddy-field were suggested. Gudle-jang Paddy-field is centrally distributed to Cheongsando and has various features as follows. First, it has the Ondol structure which is used Gudle-jang. Second, it has an irrigation canal which has functions of the tank and the prevention of cold-weather damage as well as the irrigation and drainage canal. The values of Gudle-jang Paddy-field are as follows; 1) It is the peculiar and inherent agricultural structure which is only found in Cheongsando. 2) It is the structure that the agricultural civil engineering and the agricultural water management technique of traditional methode are applied. 3) It has the worths of the traditional culture of Korea. 4) It is the important resource creating superb rural landscape of the region. In spite of these values of Gudle-jang Paddy-field, there were little efforts to preserve it. From now on, it is needed to form of sympathy about the value of Gudle-jang Paddy-field and to make efforts for preservation of it. Also the institutional and political strategy should be provided to preserve and manage Gudle-jang Paddy-field.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.45-56
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• 2014

Frozen ground in cold region consists of an upper active layer and lower permafrost which is permanently frozen land. During the summer season, the air temperature is high enough to make the frozen ground melt, which causes the reduction of soil strength and thaw settlement. These phenomena result in structural instability, so it is necessary to apply frozen ground stability techniques. Thermosyphon is a closed natural two-phase convection device to maintain the ground temperature below $0^{\circ}C$ by extracting heat from the ground and discharges it into the atmosphere. Experimental and numerical investigation has been performed to estimate the effect of the refrigerant filling ratio in thermosyphon using R-134a refrigerant and the thermal conductance of the thermosyphon.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.12
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• pp.991-997
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• 2014

This study investigated the swirling flow fields of a gun-type gas burner (GTGB) without a combustion chamber under cold flow conditions. Three velocity components and the static pressure were measured with a straight-type five-hole pressure probe (GHPP) using a non-nulling calibration method and compared with the results of an X-type hot-wire probe (X-probe) and computational fluid dynamics (CFD). The GHPP measured the velocity and static pressure for the swirling flow of the central region of the GTGB better than the X-probe but produced slightly worse results than the CFD.