• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.474-480
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• 2011

Space Imaging Sensor operated on LEO is affected from the Earth IR and Albedo as well as the Sun Radiation. The Imaging Sensor exposed to extreme environment needs thermal control subsystem to be maintained in operating/non-operating allowable temperature. Generally, units are periodically dissipated on spacecraft panel, which is designed as radiator. Because thermal design of the imaging sensor inside a spacecraft is isolated, heat pipes connected to radiators on the panel efficiently transfer dissipation of the units. First of all, preliminary thermal design of radiating area and heater power is performed through steady energy balance equation. Based on preliminary thermal design, on-orbit thermal analysis is calculated by SINDA, so calculation for thermal design could be easy and rapid. Radiators are designed to rib-type in order to maintain radiating performance and reduce mass. After on-orbit thermal analysis, thermal requirements for Space Imaging Sensor are verified.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.155-169
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• 2004

Space launch vehicles and reentry vehicles are exposed to extreme heating conditions due to high aerodynamic heating while flying at high Mach numbers in the atmosphere. To protect the vehicle itself or the payload from the aerodynamic heating, the thermal load imposed on the surface should be exactly predicted and proper thermal protection should be applied based on the prediction results. But this requires rigorous thermal analysis and testing to prevent loss of payload capacity caused by excessive heat shielding, and the amount of thermal protection material to be applied is determined through aerodynamic heating tests. Various design points to be considered to upgrade the prototype aerodynamic thermal simulation facility(ATSF) used for the KSR-series sounding rocket development to the one suitable for the KSLV(Korean Space Launch Vehicle)-series launch vehicle are considered in this research. The need and limitation for the facility are first considered, and the functions required for KSLV testing are determined. The specifications of the upgraded facility are briefly suggested and these results will be used for the future fabrication and installation of the facility.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.951-956
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• 2005

Selection of oxygen-tolerant strains and elucidation of their oxygen tolerance mechanism were crucial for effective use of bifidobacteria. Oxygen-tolerant bifidobacteria were able to significantly remove environmental oxygen (oxygen removal activity) as compared to oxygen-sensitive strains. Most oxygen removal activity was inhibited by heat treatment and exposure to extreme pH (2.0) of bifidobacterial cell. NADH oxidase was major enzyme related to oxygen removal activity. Oxygen-tolerant bifidobacteria possessed high NADH peroxidase activity level to detoxify $H_2O_2$ formed from reaction of NADH oxidase. Addition of oxygen to anaerobic culture broth significantly increased activities of HADH oxidase and NADH peroxidase within 1hr and rapid increment of oxygen concentration was prevented. Results showed NADH oxidase and NADH peroxidase of oxygen-tolerant bifidobacteria played important roles in elimination of oxygen and oxygen metabolite $(H_2O_2)$.

• Journal of Integrative Natural Science
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• v.13 no.1
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• pp.27-33
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• 2020

The unsustainable human activities like increased use of automobiles, heavy industrialization and the use of large volumes of fertilizers, chemicals and pesticides in the agricultural land cause climate change problems in one way or another. Under normal circumstances, the heat radiations from the sun will be reflected back. An excessive volume of GHGs in the atmosphere would prevent these radiations from reflecting back. East Asia is facing severe climate change issues in recent times. A lot of climate change problems such as hurricanes and floods have been reported from this region in the last couple of decades. The study aimed at investigating the climate change in East Asia with changing Sea Surface Temperature (SST). The study adopted a quantitative research method with a case study research design where a deliberate focus was made on the East Asia Region. Secondary data was gathered and analyzed to yield both descriptive and inferential statistics. The study concluded that the impact of East Asia Climate variability was significant mainly for some extreme events. Also, the study concluded that there was a significant link between the change of the East Asia climate variability and that of the sea surface temperature. Further, the study concluded that a linear relationship existed between the sea surface temperature and the climate of East Asia. Hence, a linear regression was a significant predictor of the East Asia Climate (EAC) based on changing sea surface temperature. The model revealed that 37.4% of the variations in the climate change index were explained by the changes in the sea surface temperature. The climate was expected to change with a value of 49.48 for a unit change in the sea surface temperature.

• Journal of the Korean Geotechnical Society
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• v.36 no.8
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• pp.49-60
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• 2020

A fully coupled thermo-hydro-mechanical model is established to evaluate frost heave behaviour of saturated frost-susceptible soils. The method is based on mass conservation, energy conservation, and force equilibrium equations, which are fully coupled with each other. These equations consider various physical phenomena during one-dimensional soil freezing such as latent heat of phase change, thermal conductivity changes, pore water migration, and the accompanying mechanical deformation. Using the thermo-hydro-mechanical model, a sensitivity analysis study is conducted to examine the effects of the geotechnical parameters and external conditions on the amount of frost heave and frost heaving rate. According to the results of the sensitivity analysis, initial void ratio significantly affects each objective as an individual parameter, whereas soil particle thermal conductivity and temperature gradient affect frost heave behaviour to a greater degree when applied simultaneously. The factors considered in this study are the main factors affecting the frost heaving amount and rate, which may be used to determine the frostbite sensitivity of a new sample.

• Journal of the Korea Furniture Society
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• v.20 no.5
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• pp.467-479
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• 2009

The high-tech computer technology developments have greatly affected the area of design education. Starting from the mid 80s, innovations in visual presentation methods have heightened with 2D computer graphic programs, CAD & 3D modeling, and Rapid Prototype that allows dimensional generation. The specialty and quality in design studio education have advanced due to the development in presentation methods such as Power Point and Keynote. But there are many problems with the current method of presenting the visual outcome in a data format using beam projectors, which is a vertical presenting method compared to the old studio study method of conducting discussions and reviews based on the substantial outcome. The essence of studio study that allows for comparisons and analysis by horizontally opening up the various work outcomes is being offset. Also the requirement for manual idea sketching work that plays an important role in the initial design phase continuing to decrease due to the digital working process dependence and cumbersome procedures in the presentation. In order to resolve this problem, the CALM system (Class Applied LCD Modular System) has been developed that replaces the method of attaching the sketches or renderings on the wall with a digital multi-display system. In a nutshell, individuals will upload the outcomes online and display them on the CALM system studio that is composed of 32 LCD (Columns: 4 $\times$ Rows: 8) monitors that are 19 inches in size so that various personnel can openly study the design outcomes. Also the central 42 inch PDP monitor that offers touch pad capability allows each design outcome to be described and examined by expanding. The concept phase of this development process has elevated to the production of an operating prototype that is being reviewed of its practicality. It is considered that the development of this system will decrease the extreme tendency of depending on digital operation but achieve revitalization of a more realistic and opened studio study environment compared to the individual consulting method of the old study approach.

• Journal of Environmental Science International
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• v.28 no.2
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• pp.169-182
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• 2019

Temporal and spatial variations in surface ozone concentrations in Busan were investigated by using observation data from urban air quality sites during 2001-2016. The annual ozone concentrations showed a significant increasing trend of $+0.40ppb\;yr^{-1}$ in this period, with a more rapid increase of $+0.81ppb\;yr-1$ since 2010. For the monthly analysis, the increase in ozone concentration was the greatest in August ($+0.68ppb\;yr-1$). These ozone trends were due mainly to rising temperature ($+0.05^{\circ}C\;yr^{-1}$) and weak decreasing precipitation ($-6.42mm\;yr^{-1}$). However, the extreme weather events (heat wave, localized heavy rain, etc.) lead to an increase in short-term variability of ozone since 2010. The relatively low ozone concentrations in the downtown area were caused by high NOx emissions from mobile sources. The increases in ozone concentrations were observed at most of the air quality monitoring sites due to the reductions in anthropogenic emissions of NOx during 2001-2015. However, in the southern coastal area, lower rates of increase in ozone concentrations were observed by $-0.10{\sim}0.25ppb\;yr^{-1}$ due to the significant NOx emitted by ships in the Busan port and Busan new port.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.1
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• pp.121-130
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• 2019

The purpose of this study is to determine the amount of irrigation water for upland crop growth based on the 30 year of historical rainfall data and the water management guidelines as a reference. Five regions and ten crops were selected by their cultivation size. The changes of soil moisture contents were calculated using daily mean rainfall and irrigation demand. This study assumed that crops are irrigated when the soil moisture contents fell below of the field capacity for more than 5 days, which is the drought condition defined by RDA. The maximum irrigation water requirements was 167.2 mm for chinese cabbage during the growing season, which was followed by corn (112.0 mm), daikon (102.3 mm), spinach (66.1 mm), lettuce (56.7 mm), pepper (46.5 mm), potato (33.9 mm), sweet tomato (27.4 mm), peanut (11.5 mm) and bean (10.3 mm), The results of this study could contribute to providing valuable data to determine the capacity of irrigation facilities and to establish the emergency operation plans under extreme unfavorable weather condition (heat wave, etc.) for crop growth.

• Journal of Sensor Science and Technology
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• v.30 no.2
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• pp.94-98
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• 2021

In this study, pure and Co3O4/CoFe2O4-loaded Indium oxide (In2O3) nanofibers were synthesized by the electrospinning of an Indium/Polyvinylpyrrolidone precursor solution containing cobalt and iron bimetallic zeolitic imidazolate frameworks and subsequent heat treatment. The ethanol, toluene, p-xylene, benzene, carbon monodxide, and hydrogen gas sensing characteristics of the solution were measured at 250-400 ℃. 0.5 at%-Co3O4/CoFe2O4-loaded In2O3 nanofibers exhibited extreme response (resistance ratio - 1) to 5 ppm of ethanol (210.5) at 250 ℃ and excellent selectivity over the interfering gases. In contrast, pure In2O3 nanofibers exhibited relatively low responses to all the analyte gases and low selectivity above 250-400 ℃. The superior response and selectivity toward ethanol is explained by the catalytic roles of Co3O4 and CoFe2O4 in gas sensing reaction and the electronic sensitization induced by the formation of p (Co3O4/CoFe2O4)-n (In2O3) junctions.

• Atmosphere
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• v.31 no.5
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• pp.539-551
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• 2021

In this paper, the weather records in 'Nanjung Ilgi' were investigated and the weather characteristics of the southern coast of Korea (SC_Korea) was discussed. The Nanjung Ilgi is a personal diary written by admiral Yi Sun-sin from January 1592 to November 1598 during the 7-year war caused by the Japanese invasion. He is a respected great leader in the history of world naval warfare, winning all 23 battles against the Japanese. Of the 1593 days of diaries currently preserved, only 42 days have no weather records. Weather was recorded in detail, including sky conditions, precipitation, wind characteristics and others. Weather records were extracted from the diary, converted to the solar calendar, and compared with the meteorological data of Yeosu. The average annual precipitation day is about 90 days, which is similar to the current 95~100 days. As in the current climate, precipitation frequently occurs for about 30 days in summer, but less than 15 days in other seasons, and the rainy season starts from June 14 to 21 and ends from July 6 to 17. It seems that the abnormal cold and heat phenomena, which deviate significantly from the seasonal average climate, occurred on 6 and 21 days, respectively, over 7 years. This means that the weather records of Nanjung Ilgi can be used as valuable data on the climate of SC_Korea in the late 16th century. The fact that he recorded the weather even in such extreme battle conditions shows that he clearly recognized the importance of weather in warfare.