• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.87-94
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• 2019

In this paper, we test procedures to demonstrate operating environmental conditions that can be exposed to UAV during its life-cycle are proposed. They are set up to be used in a large-sized climate chamber, one of the facilities of the Agency for Defense Development corresponding with the system requirements. The test steps and profile details were more specifically suggested for rainfall, humidity, and temperature (low-temperature storage and operation, high-temperature operation and solar radiation), and MIL-STD-810G w/Change-1-based.

• Journal of Environmental Science International
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• v.32 no.2
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• pp.131-137
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• 2023

Filter and microbalance sensitivity in measuring fine particulate matter mass is greatly influenced by particulate properties and environmental factors. Temperature and humidity control inside a measuring chamber with a microbalance, and neutralization of static charges on filters are essential for consistent filter weighing. Commercial weighing chambers are expensive with a unit price of tens of millions won. This study developed an inexpensive weighing chamber for weighing fine particulate matter and evaluatedits weighing performance. A microbalance with 1 ㎍ precision was used to measure the weight of a filter. The microbalance was set in a transparent acrylic enclosure (100 × 60 × 65 cm³) equipped with temperature and humidity control equipments. Weighing performance of the chamber was examined using Teflon filters with or without different particulate sample types. Temperature and humidity were maintained at approximately 23.2±1.2 ℃ and 36.2±1.8℃ for 8 days, respectively.

• Journal of Korean Society of Archives and Records Management
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• v.15 no.2
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• pp.165-179
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• 2015

Archives have historical and academic values. That is why the study of preservation conditions and the environment for the effective management of various records progress. However, materials such as paper and adhesives will inevitably cause biological damages. These damages spread into the inner side of archives, which would make it impossible to recover. For example, archival records from Malaysia and Oman are easily exposed to biological damage because of these countries' hot and humid climate. As such, once records are damaged, disinfection operations are customary in these areas. Methyl bromide (MeBr) and ethylene oxide (EtO) were used in the disinfection process as they showed good insecticidal effect. However their antibacterial effect are negligible. As such, the need for an environmental-friendly fumigator was evident. An environmental-friendly fumigator is designed to improve storage stability. Such equipment is expected to contribute to prevention of damages to cultural heritages through its use of vaporization technology, maintenance of a disinfection space (chamber), and self-generation of nitrogen.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.71-81
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• 2020

In Korea, more than 70% of the ammonia(NH₃) released into the atmosphere is known to originate from livestock manure. The total emission (kg year^-1) is calculated by multiplying the emission factor (kg head^-1 yr^-1) and the activity data (head). To improve the accuracy and reliability of the NH₃ emission estimation process, an accurate account of livestock manure production, calculation of NH₃ conversion and generation during the composting and liquefaction of manure, estimation of NH₃ generation in the storage and transportation of manure and compost, and a comparative study of NH₃ emission during the soil spreading process must be performed. Compared to the US and EU-28, in particular, the domestic emission factor is relatively even and the spatial/temporal scale is not broken down sufficiently to reflect the domestic situation. As a way to improve the accuracy and expertise of estimating NH₃ emission factors, a 'dynamic chamber-capture system' can be utilized, which allows complex considerations of compost, liquid manure, soil, and climate characteristics. By reviewing and comparing the data related to domestic and foreign NH₃ emission, we identified shortcomings in the current domestic system and the directions to be taken and suggested a chamber system that could estimate NH₃ emission flux. It is also necessary to establish a methodology for mesocosm systems in the field, in addition to indoor chamber systems, to be linked with practical policies, such as the calculation of new emission factors for missing sources.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.105-113
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• 2021

This paper delineates the applied thermal environmental test profiles using test conditions and procedures based on MIL-STD-810 Method 501 (High Temperature Test Method) and Method 502 (Low Temperature Test Method). The test profiles have been optimized in order to comply with export customer's requirements and product reliability in high and low temperature environment for XKT-1 (KT-1 Export Version) aircraft. Additionally, the tests are suitable for large sized environmental chambers, which is one of the facilities of ADD (Agency for Defense Development) according to ETEMP (Environmental Test and Evaluation Master Plan). The results of these test profiles and test executions satisfy the customer requirements and product reliability. The present paper can be applied to the other export programs with more severe temperature conditions.

• Atmosphere
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• v.33 no.2
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• pp.105-124
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• 2023

Research papers published in the Korean Meteorological Society (KMS) journals by the members of KMS since the establishment of KMS in 1963 in the field of atmospheric physics are summarized. A significant number of research papers published in other international journals are also cited in this paper to highlight the achievement of the KMS members in international academic community. The aim is to illustrate the historical development of research activities of the KMS members in the field of atmospheric physics, and indeed it is found that the KMS members have made enormous progress in research publications quantitatively and qualitatively in the field of atmospheric physics. In detail, however, observational studies of aerosol physical properties and cloud and precipitation physics were very active, and studies on cloud physics parameterization for cloud modeling were highly recognized in the world, but observational and theoretical studies of atmospheric radiation were relatively lacking and solicit more contribution from the KMS members.

• Journal of Bio-Environment Control
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• v.32 no.2
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• pp.106-114
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• 2023

With rising concerns about pesticide spray drift by aerial application, this study attempt to evaluate aerodynamic property and collection efficiency of spray drift according to the leaf area index (LAI) of crop for preventing undesirable pesticide contamination by the spray-drift tunnel experiment. The collection efficiency of the plant with 'Low' LAI was measured at 16.13% at a wind speed of 1 m·s^-1. As the wind speed increased to 2 m·s^-1, the collection efficiency of plant with the same LAI level increased 1.80 times higher to 29.06%. For the 'Medium' level LAI, the collection efficiency was 24.42% and 43.06% at wind speed of 1 m·s^-1 and 2 m·s^-1, respectively. For the 'High' level LAI, it also increased 1.24 times higher as the wind speed increased. The measured results indicated that the collection of spray droplets by leaves were increased with LAI and wind speed. This also implied that dense leaves would have more advantages for preventing the drift of airborne spray droplets. Aerodynamic properties also tended to increase as the LAI increased, and the regression analysis of quadric equation and power law equation showed high explanatory of 0.96-0.99.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.3
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• pp.248-253
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• 2015

This study was conducted to determine the impact of temperature elevated based on climate change scenario on growth and fruit quality of red pepper (Capsicum annuum L.) in walk-in plant growth chambers. The intraday temperatures of climate normal years (IT) were determined using intraday mean temperatures of climatic normal years (1971~2000) in the Andong Province during the growing season (May 1~July 30). Red pepper plants were cultivated under different temperatures (starting at IT rise by up to $6^{\circ}C$, $2^{\circ}C$ increment). Plant height, stem diameter, branch number, leaf number, fresh weight and dry weight increased under the temperatures higher than IT. The number of flower was the greatest under IT+$2^{\circ}C$ (mean temperature at $22.8^{\circ}C$). The total number and the weight of fruits were the highest under IT+$2^{\circ}C$. While the fruit weight, fruit length and fruit diameter decreased more than IT+$2^{\circ}C$ as the temperature increased gradually. These results concluded that in condition that the current diurnal temperature change cycle is maintained in Andong area, in accordance with climate change scenarios, when the temperature rise $2^{\circ}C$ higher than intraday temperature of Andong area the quantity of pepper fruits will increase while maintaining quality, but increases more than that degree yields are expected to decrease significantly. This result suggests that the fruit yield could increase under IT+$2^{\circ}C$ and fruit quality could maintain great, but the fruit yield could decrease under the temperatures higher than IT+$2^{\circ}C$.

• Korean Journal of Environmental Biology
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• v.35 no.1
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• pp.13-20
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• 2017

Greenhouse gas emission from agricultural land is recognized as an important factor influencing climatic change. In this study, the national $CO_2$ emission was estimated for paddy soils, using soil GHG emission model (DNDC) with $1km^2$ scale. To evaluate the applicability of the model in Korea, verification was carried out based on field measurement data using a closed chamber. The total national $CO_2$ emission in 2015 was estimated at $5,314kt\;CO_2-eq$, with the emission per unit area ranging from $2.2{\sim}10.0t\;CO_2-eq\;ha^{-1}$. Geographically, the emission of Jeju province was particularly high, and the emission from the southern region was generally high. The result of the model verification analysis with the field data collected in this study (n=16) indicates that the relation between the field measurement and the model prediction was statistically similar (RMSE=22.2, ME=0.28, and $r^2=0.53$). More field measurements under various climate conditions, and subsequent model verification with extended data sets, are further required.

• Journal of Korean Society of Forest Science
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• v.110 no.4
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• pp.554-568
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• 2021

Forests are the largest carbon (C) sinks in terrestrial ecosystems. Recently, as enhancing forest C sequestration capacity has been proposed as a basic direction of the Republic of Korea's "2050 Carbon Neutral Strategy," accurate estimation of forest C sequestration has been emphasized. According to the Intergovernmental Panel on Climate Change guidelines, sequestration quantity is calculated from changes in C stocks in forest C pools, such as biomass, deadwood, litter and soil layer, and harvested wood products. However, in Korea, only the overstory biomass increase is now considered the amount of sequestration quantity, so there can be a significant difference from the actual forest C sequestration. In this study, we quantified forest C exchange through C flux measurement using an eddy covariance system and an automated soil chamber system in a 57-year-old Korean pine plantation located in Mt. Taehwa, Gwangju-si, Gyeonggi-do. Then, the net amount of C sequestration was compared with the amount of the overstory biomass increase. We estimated the annual C stock change in the remaining C pools by comparing the net sequestration amount from the C flux measurement with the overstory biomass increase and C stock change in the litter layer. Therefore, the net C sequestration of the Korean pine plantation estimated from the flux measurement was 5.96 MgC ha^-1, which was about 2.2 times greater than 2.77 MgC ha^-1 of the overstory biomass increase. The annual C stock increase in the litter layer was estimated to be 0.75 MgC ha^-1, resulting in a total annual C stock increase of 2.45 MgC ha^-1 in the remaining C pools. Our results indicate that the domestic forest is a larger C sink than the current methods, implying that more accurate calculations of the C sequestration capacity are necessary to quantify C stock changes in C pools along with the C flux measurement.