• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.87-87
• /
• 2011

Oxide semiconductors are attractive materials for thin-film electronics and optoelectronics due to compatibility with synthesis on large-area, glass and flexible substrate. However, development of thin-film electronics has been hampered by the limited number of semiconducting oxides that are p-type. We report on the effect of the oxygen partial pressure ratio in the gas mixture on the electrical and optical properties of spinel Mg:$ZnCo_2O_4$ thin films deposited at room temperature using RF sputtering, that exhibit p-type conduction. The thin-films are deposited at room temperature in a background of oxygen using a polycrystalline Mg:$ZnCo_2O_4$ ablation target. The p-type conduction is confirmed by positive Seebeck coefficient and positive Hall coefficient. The electrical resistivity and carrier concentration in on dependent Mg:$ZnCo_2O_4$ thin films were found to be dependent on the oxygen partial pressure ratio. As a result, it is revealed that the Mg:$ZnCo_2O_4$ thin-films were greatly influenced on the electrical and optical properties by the oxygen partial pressure condition. The visible region of the spectrum of 36~85%, and hole mobility of 1.1~3.7 $cm^2$/Vs, were obtained.

• Journal of Ginseng Research
• /
• v.29 no.2
• /
• pp.113-118
• /
• 2005

This study was to examine the effect of the opening ratio (area of spile hole/total surface area) of plastic container and storage temperature on physicochemical changes of fresh ginseng. At room temperature ($19\~23^{\circ}C$, RH $40\~61\%$), fungi and spoilage were observed 4 and 10 days, respectively after storing the fresh ginseng in a closed container. In storage container with $1\%$ opening ratio, fungi appeared 8 days after storage. In the container with $5\%$ and $10\%$ opening ratio, fresh ginseng showed excessive loss of moisture on the surface only after 4 days. The weight loss was most remarkable in the container with 5 and $10\%$ opening ratio. Content of maltose and sucrose decreased gradually in accordance with storage time but the extent of decreasing ratio was less significant in the container with lower opening ratio. At low temperature $(4\~9^{\circ}C,\;RH\;72\~92\%)$, no fungi but $10\%$ loss of weight was observed in the container with $5\%$ and $10\%$ opening ratio after 12 days storage. But in the tightly closed container and $1\%$ opening ratio for spiting, fresh ginseng showed good appearance even after 30 days of storage. Free sugars, especially maltose revealed gradual decrease but sucrose gradually increase following decrease at the beginning. This result suggests that storage condition of low temperature and opening ratio of plastic box less than $1\%$ can extend storage span of fresh ginseng significantly.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.313-323
• /
• 2003

The sliding wear behaviors of Zircaloy-4 nuclear fuel rod were investigated using two support springs with convex and concave shapes in room temperature air and water. The main focus is to compare the wear behavior of various test variables such as slip amplitude, environment, contact contours with different spring shape and a number of cycles. The results indicated that wear volume and maximum wear depth increased with slip amplitude in both air and water, but their trends tended to change according to the spring shapes and test environments. In air condition, the wear volume was controlled by wear debris behavior generated on worn surface. As a result, final wear volume and maximum wear depth decreased if a ratio of protruded wear volume to worn area $(D_p)$ would be saturated to specific value. This is because wear particle layer could accommodate large strain by accumulating and transforming wear particle layer. However, in water condition, metal-to metal contact was more dominant and wear volume was greatly affected by changed mechanical behavior between contact surfaces since wear debris should be generated after repeated plastic deformation and fracture. After wear test, worn surfaces were examined using optical microscope and SEM and details of wear mechanism were discussed using a ratio of wear volume to worn area $(D_e)$ at each test condition.

• Restorative Dentistry and Endodontics
• /
• v.23 no.2
• /
• pp.607-617
• /
• 1998

The purpose of this study was to evaluate the apical sealing ability of lateral condensation method, vertical condensation method, and MicroSeal obturation system. Sixty-four extracted anterior teeth were instrumented to #40 using Profile. Three groups of 20 teeth were obturated by lateral condensation technique, vertical condensation technique, and and MicroSeal obturation system. Control group were not obturated. Teeth were immersed in resorcinol-formaldehyde resin for 5 days at $4^{\circ}C$, and the resin was allowed to polymerize completely for 4 days at room temperature. Teeth were ground horizontally at 1,5mm(level 1), 2.5mm(level 2), and 3.5mm(level 3) from the anatomic apex and examined with a stereomicroscope at X40 magnification. The photographs were taken a at X40 magnification of the filling in each level and scanned. The leakage area, which was filled with the resin, was measured at each of the three levels. Each ratio of leakage was evaluated by calculating the ratio of thearea of the resin to the total area of the canal and was analyzed statistically. The results were as followed: 1. Vertical condensation group had significantly higher percentage of the area which was obturated by gutta percha than other two technique at each level. 2. At the level 1, there was the greatest leakage in the lateral condensation group, but there was no statistically significant(P>0.05) 3. At the level 2, there was the least leakage in the MicroSeal group, and the most leakage in the lateral condensation group. There was statistically significant difference between the MicroSeal group and the lateral condensation group(P<0.05). 4. At the level 3, there was least leakage in the vertical condensation group, and the most leakage in the lateral condensation group. There was statistically significant difference between the vertical condensation group and the lateral condensation group(P<0.05).

• KIEAE Journal
• /
• v.11 no.2
• /
• pp.105-111
• /
• 2011

Aims of this study is to investigate the daylighting control strategy of venetian blind system was performed as a function of ratio of shading height to window and slat angles in the preliminary stage of the parametric study. Floor-to-ceiling window walls of living spaces are used widely in apartment buildings since the Korean government has legally allowed elimination of the balcony area. Enlarging living area by balcony elimination, the larger glass area of window is exposed to the direct sunlight. As a common sunlight controlling device, blind system can be used in all orientations and all latitudes and it may obstruct, absorb, reflect and transmit solar radiation to building by proper adjusting. However, blind system can produce discomfort in occupant and less energy efficiency, if it has not been controlled optimally. The simulation model was based on the unit module of typical living space with balcony elimination. The room dimension was $6.0m(w){\times}6.9m(d){\times}2.7m(h)$ with floor to ceiling height of 2.5m. The blind system was simulated at five slat angles (horizontal, $30^{\circ}$, $45^{\circ}$ upward and downward tilted) and the four ratio of shading height to window (fully closed, partly opened, no-blind) using the Desktop RADIANCE 2.0 program. The series of simulation results indicates that the advantages of available daylight and outside of view can be improved by proper adjusting blind system.

• Fire Science and Engineering
• /
• v.31 no.5
• /
• pp.19-27
• /
• 2017

The effects of changes in area and location of fire source, fire growth rate, and volume of compartment on the major fire characteristics, including heat release rate, in closed compartment fires were examined. To this end, a fire simulation using Fire Dynamics Simulator (FDS) was performed for ISO 9705 room with a closed opening. As main result, it was found that the changes in the area and location of fire source did not significantly affect the thermal and chemical characteristics inside the compartment, such as maximum heat release rate, total heat release, maximum temperature at upper layeras well as species concentrations. However, increasinthe fire growth rate and volume of compartment resulted in increase of the maximum heat release rate and total heat release, decrease in the limiting oxygen concentration and increase in the maximum CO concentration. Finally, a methodology for the application of fire growth curves to closed compartment fires was proposed by deriving the correlation of the maximum heat release rate expressed as a function of the fire growth rate and the volume ratio of compartment based on the ISO 9705 room.

• The Korean Journal of Physiology
• /
• v.3 no.1
• /
• pp.19-28
• /
• 1969

Skin temperatures on 10 sites and rectal temperature at every 10 minutes, oxygen consumption at every 20 minutes were measured on 18 male subjects (ages between 14 and 47 years) after exposure to cold air at $15^{\circ}C$ for two hours in a climatic room. Total body fat measured by means of a skinfold method and ratio of body surface area (S) to body volume (V), S/V, were utilized as basis of observations. Surface area was calculated after DuBois equation and body volume was calculated by our original formula. In influencing on the heat loss from the body core to the cold environment, % fat showed inverse relations, whereas, S/V ratio showed direct relations. Thus these two factors acted antagonistically on the body heat loss. Local skin temperatures showed negative correlations with skinfold thickness on the same site, nemaly, on chest, r=-.567; on back, r=-.507; and on upper arm, r=-.353. The other 7 skin sites showed low correlations with % fat. Minimum mean weighted skin temperature (MWST) showed a negative correlation (r=-.443) with % fat, and showed no correlation with S/V ratio. Oxygen consumption in the cold air at $15^{\circ}C$ increased from the first measurement at 20 minutes after exposure and maintained the same increasing trend up to 120 minutes. ${\Delta}T_R$ was greater in tile lean subjects who showed a greater % change in oxygen consumption. The antagonistic actions of % fat and S/V ratio on the heat loss were manifested by observations as follows: minimum rectal temperature was higher In fat subjects (r=.600) and lower in subjects with a greater S/V ratio (=-.582), ${\Delta}T_R$ was smaller in fat subjects (r=-.738) and greater in subjects with a greater S/V ratio (r=.618). Temperature difference between body core and skin surface (minimum rectal temperature minus minimum MWST) showed a positive correlation with % fat (r=.600) and a negative correlation with S/V ratio (r=-.881). Decrease in the mean body temperature and heat debt, respectively, showed negative correlations with % fat and positive correlations with S/V ratio.

• Korean Institute of Interior Design Journal
• /
• v.19 no.6
• /
• pp.224-232
• /
• 2010

This paper aims to identify the characteristics and the current situation of the architectural characteristics, children's characters using facilities, and status of management and utilization by surveying 'Day Service for Children' in Tokyo-do. First, About the status of management and utilization, 'Day Service for Children' is operated by a local government, NPO corporate group and social welfare corporate. There are not big differences of the care program or running hours depending on operating principals but there are differences depending on staff organization, number of children and space constitution. Also, infants ratio at 'Day Service for Children' is high for the purpose of detecting disability early and supporting their development early. They have diverse disabilities but developmental disabilities' ratios high and most children are using both this facility and normal nursery centers together. Samples for proper child care based on status of space constitutions were installing lock, raising door knobs and using softer floor materials which are for children's safety. For the problem of space utilization, most comments were about lack of space which is not enough for teaching and training materials. Therefore, as an example, observation rooms for parents and teachers were sometimes used as storages and it changes teachers' moving direction, staying area and behavior zone. The programs of 'Day Service for Children' are divided to group teaching and private one. It will be the best if they have separate spaces such as group class room, private class room and play room. When they were operated by NPO corporate group or Social welfare corporate, there are many cases that their space was not properly zoned for each activity.

• Journal of the Korean Institute of Rural Architecture
• /
• v.5 no.1
• /
• pp.32-41
• /
• 2003

After the 1988 Seoul Olympics, a lot of Culture & Arts Centers have been built in Korea. There have been raised questions on the frequency of room use and the occupancy of seats, but there are not enough architectural data for the Culture & Arts Centers in Korea. This paper focuses on the investigation of the architectural features of the Culture & Art Centers, such as the spatial sizes, the composition ratio of the performing art hall area to the overall facility area, the sizes and proportions of seat zone to stage zone, the average area per one person at the seat zone, the wide and the height of the procenium, the height of fly loft, and the number of users per one program. We could find out some meaning results. The composition ratios of the performing art hall area to the overall area of the facilities distribute with a wide range. The floor areas of 1500 through 2000 seat performing art halls are larger than $13,000m^2$. The average area per one person for seat zone and stage zone is approximately $0.8m^2$. All facilities we investigated have the types of the procenium stage. Almost all of the facilities have high quality stage conditions and equipments, but few programs use the various stage equipments and all of the main, side, and rear stages. To resolve this problems, various programs have to be developed for encouraging more people to use the Culture & Art Centers.

• Korean Institute of Interior Design Journal
• /
• v.24 no.6
• /
• pp.154-162
• /
• 2015

As there is no case study with current status, measurements or description on the state of actual site of rural area only, the delivery of actual conditions about such an area is significantly limited. The purpose of this study is to pinpoint issues with housing conditions of low-income family with disabled members in the rural area. For such a purpose, 25 households of disabled people have been visited for interview, on-site research and survey, of which results are summed up in this paper as following: First, average monthly income of such family turned out to be KRW 480,000, most of which is from the government subsidy. High ratio of such families has resided in a house with average size of approximately 56m2 for about 24 years. Secondly the most needed maintenance work with top priority was for the toilet, and many of the interviewees expressed their discomfort about small size of their bathrooms and inconvenient facilities therein. Thirdly, most of such houses had too high thresholds that posed danger and inconvenience. Such thresholds had average height of 13cm, which can be considered as completely inconsiderate of disabled users. Fourth issue was that these people needed safety handle that will enable them to stand up or to be in the standing posture in the living room and bedroom where they spend most of their time. Fifthly, they wanted finishing materials with waterproof functionality as well as replacement of finishing materials and wallpaper which were too old and caused hygiene issues. As these issues represent, current housing for disabled people in the rural area turned out to be poor and risky space rather than the place where difficulty of individual situation can be resolved or their disability can be complemented. Thus it can be determined that now is the time to arrange the solutions for such housing difficulties and to establish customized housing plan to ensure safety and convenience.