• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.25 no.1
• /
• pp.15-28
• /
• 1992

Temporal variations of the path of the East Korea Warm Current(EKWC) which flows northward along the east coast of Korea were analysed to investigate whether the EKWC directly influences the existence of the so-called Warm Core in the Ulreung basin. From the 13 years(1975-1987) data of the Fisheries Research and Development Agency(FRDA), the $10^{\circ}C$ isotherm at the 100m depth and the depth of $2^{\circ}C$ isotherm and the temperature field at the 200m depth were used for identification of the path and the central position of the Warm Core. Sea surface winds computed from the surface pressure charts gave the monthly-averaged wind stress curl over the East Sea which was used for determination of the Sverdrup transport. And the mass transport stream functions were computed by use of the Sverdrup balance. The variations of the path show that the EKWC does not always have a fixed path and fluctuates with time. And the existence of the Warm Core is independent upon the presence of the EKWC even when the EKWC doesn't flow northward along the east coast of Korea. In view of the mass transport stream functions, the influences of the sea surface winds on the branching of the Tsushima Warm Currents and the presence of the EKWC were investigated. The presence of the EKWC may be hindered by the southward flow driven by the sea surface winds when the Tsushima currents are rather weak. A very weak correlation exists between the north-south component of the Sverdrup transport and the position of the Warm Core. However, a small but significant part of the southward transport across the latitudinal line of $38^{\circ}N$ indicates that cold water from the northern part of the East Sea may be driven and be forced to flow beneath the permanent thermocline in such a way that the thermal structure of the Warm Core and its position might be changed.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2004.03b
• /
• pp.453-460
• /
• 2004

To prevent penetration of rainwater into the landfill site is the main purpose of the final cover in landfill sites. Conventional designs of landfill covers uses geotextiles such as geomembrane and GCL, and clay liners to lower the permeability of final covers of landfill sites. However, differential settlement and the variation of temperature in landfill sites cause the development of cracks or structural damage inside the final cover and it is also difficult to obtain clay - the main material of the compacted clay liner in Korea. Thus the former final cover system that suggests geomembrane and GCL or compacted clay liner has several limitations. Therefore, an alternative method is necessary and one of them is the application of SRSL(self-Recovering Sustainable Liner) material. SRSL is two different layers consist of individual materials that react with each other and form precipitates, and with this process lowers the permeability of the landfill final cover. SRSL generally is made up of two layers, so that when a internal crack occurs the reactants of the two layers migrate towards the crack and heal it by forming another liner. In this study the applicability of SRSL material for landfill final cover was examined by performing; (1) jar test to verify the formation of precipitate in the mixture of each reactants, (2) falling head test considering the field stress in order to confirm the decrease of permeability or prove that the hydraulic condctivity is lower than the regulations, (3) compression tests to judge weather if the strength satisfies the restricts for landfills, (4) freeze/thaw test to check the applicability of SRSL for domestic climate. In addition, the application of waste materials in the environmental and economical aspect was inspected, and finally the possibility of secondary contamination due to the waste materials was examined by performing elution tests.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.29 no.4
• /
• pp.427-435
• /
• 1984

Alfalfa field was established to investigate seasonal changes of nodule activity and contents of carbohydrates, and nitrogen, and also to examine their relationships in alfalfa (Medicago sativa L.). Periodical sampling of alfalfa in cutting and uncutting plots was collected to measure growth of plants, development and activity of nodule, and content of carbohydrates and nitrogen in the third year following year of establishment. Nodule activity of alfalfa root appeared to early April, increased to a maximum in beginning of June (flowering stage), and then decreased and generally remained low from late-July to mid-August, and again increased from early September, and then decreased and generally remained low for the rest of growing season. After flowering, nodule weight tended to decrease slowly throughout the growing season. Until flowering stage, increase of dry weight was closely related with that of nodule activity. But after flowering the curve pattern of dry weight did not fit to that of nodule activity due to decrease of supply of assimilate to nodule, drought, and high temperature. Total nonstructural carbohydrates in roots were closely correlated with nodule weight and nodule activity. While, nitrogen contents in leaves were closely correlated with nodule weight and nodule activity. Also cutting on July prevented unnessesary losses of respiration during summer to provide rapid recovery of nodule activity.

• Journal of Veterinary Science
• /
• v.22 no.6
• /
• pp.87.1-87.12
• /
• 2021

Background: African swine fever virus (ASFV), classical swine fever virus (CSFV), and porcine reproductive and respiratory syndrome virus (PRRSV) are still prevalent in many regions of China. Co-infections make it difficult to distinguish their clinical symptoms and pathological changes. Therefore, a rapid and specific method is needed for the differential detection of these pathogens. Objectives: The aim of this study was to develop a multiplex real-time quantitative reverse transcription polymerase chain reaction (multiplex qRT-PCR) for the simultaneous differential detection of ASFV, CSFV, and PRRSV. Methods: Three pairs of primers and TaqMan probes targeting the ASFV p72 gene, CSFV 5' untranslated region, and PRRSV ORF7 gene were designed. After optimizing the reaction conditions, including the annealing temperature, primer concentration, and probe concentration, multiplex qRT-PCR for simultaneous and differential detection of ASFV, CSFV, and PRRSV was developed. Subsequently, 1,143 clinical samples were detected to verify the practicality of the assay. Results: The multiplex qRT-PCR assay could specifically and simultaneously detect the ASFV, CSFV, and PRRSV with a detection limit of 1.78 × 10⁰ copies for the ASFV, CSFV, and PRRSV, but could not amplify the other major porcine viruses, such as pseudorabies virus, porcine circovirus type 1 (PCV1), PCV2, PCV3, foot-and-mouth disease virus, porcine parvovirus, atypical porcine pestivirus, and Senecavirus A. The assay had good repeatability with coefficients of variation of intra- and inter-assay of less than 1.2%. Finally, the assay was used to detect 1,143 clinical samples to evaluate its practicality in the field. The positive rates of ASFV, CSFV, and PRRSV were 25.63%, 9.36%, and 17.50%, respectively. The co-infection rates of ASFV+CSFV, ASFV+PRRSV, CSFV+PRRSV, and ASFV+CSFV+PRRSV were 2.45%, 2.36%, 1.57%, and 0.17%, respectively. Conclusions: The multiplex qRT-PCR developed in this study could provide a rapid, sensitive, specific diagnostic tool for the simultaneous and differential detection of ASFV, CSFV, and PRRSV.

• Journal of Ecology and Environment
• /
• v.41 no.12
• /
• pp.336-344
• /
• 2017

Background: Because of climate change, interest in the development of carbon pools has increased. In agricultural ecosystems, which can be more intensively managed than forests, measures to control carbon dioxide ($CO_2$) emission and absorption levels can be applied relatively easily. However, crop residues may be released into the atmosphere by decomposition or combustion. If we can develop scientific management techniques that enable these residues to be stocked on farmland, then it would be possible to convert farmlands from carbon emission sources to carbon pools. We analyzed and investigated soil respiration (Rs) rate characteristics according to input of carbonized residue of red peppers (Capsicum annuum L.), a widely grown crop in Korea, as a technique for increasing farmland carbon stock. Results: Rs rate in the carbonized biomass (CB) section was $226.7mg\;CO_2\;m^{-2}h^{-1}$, which was 18.1% lower than the $276.9mg\;CO_2\;m^{-2}h^{-1}$ from the red pepper residue biomass (RB) section. The Rs rate of the control was $184.1mg\;CO_2\;m^{-2}h^{-1}$. In the following year, Rs in the CB section was $204.0mg\;CO_2\;m{-2}h^{-1}$, which was 38.2% lower than the $330.1mg\;CO_2\;m^{-2}h^{-1}$ from the RB section; the control emitted $198.6mg\;CO_2\;m^{-2}h^{-1}$. Correlation between Rs and soil temperature ((Ts) at a depth of 5 cm) was $R^2=0.51$ in the RB section, which was higher than the other experimental sections. A comparison of annual decomposition rates between RB and CB showed a large difference, 41.4 and 9.7%, respectively. The results showed that carbonization of red pepper residues reduced the rates of decomposition and Rs. Conclusions: The present study confirmed that the Rs rate can be reduced by carbonization of residue biomass and putting it in the soil and that the Rs rate and Ts (5 cm) were positively correlated. Based on the results, it was determined that approximately $1.2t\;C\;ha^{-1}$ were sequestered in the soil in the first year and $3.0t\;C\;ha^{-1}$ were stored the following year. Therefore, approximately $1.5t\;C\;ha^{-1}year^{-1}$ are expected to be stocked in the soil, making it possible to develop farmlands into carbon pools.

• Journal of Appropriate Technology
• /
• v.6 no.2
• /
• pp.94-102
• /
• 2020

Renewable energy (RE) is essential to comprise sustainable societies, especially, in rural villages of developing countries. Furthermore, application of off-grid RE systems to health care can improve the quality of life. In this research, a RE-based vaccination supply management system was constructed to enlarge the cold-chain in developing countries for the safe storage and delivery of vaccines. The system was comprised of the construction of RE plants and development of vaccine carriers. RE plants were constructed and connected to health posts in local villages. The cooling mechanism of vaccine carriers was improved and monitoring devices were installed. The effect of the system on vaccine cold-chain was evaluated from the field test and topographical analysis in the southern village of Nepal. RE plants were normally operated for the vaccine refrigerator in the health post. The modified vaccine carriers had a longer operation time and better temperature control via monitoring and RE-based recharging functionality. The topographical analysis estimated that the system can cover larger region. The system prototype showed great potential regarding the possibility of a sustainable and enlarged cold-chain. Thus, RE-based vaccine supply management is expected to facilitate vaccine availability while minimizing waste in the supply chain.

• International Journal of Highway Engineering
• /
• v.10 no.4
• /
• pp.9-18
• /
• 2008

Curling is caused by the difference in the temperature and humidity by the depth of the slab in Jointed Plain Concrete Pavement. Slab curvature shape and size change due to curling exert a profound influence on the internal stress and roughness of the pavement, affecting structural and functional performance of the pavement. Direct measurement of the slab curvature entails many problems. Many measuring instruments have to be installed at the early-stage of the pavement construction, and the behavior of the slab curvature needs to be measured accurately from the early-stage. Moreover, the cost and technical difficulty are very formidable to measure the slab curvature. This study develops a measurement method for slab curvature in jointed concrete pavement at any given time by applying Power Spectrum Density Analysis and Inverse Fast Fourier Transformation to the profile data, that can be easily obtained at the construction field site. The effectiveness of this developed method is verified by measuring the profile data of the test road of jointed concrete pavement at an inland central expressway by the hour and by examining the result of extracting the slab curvature shape from this profile data. Additionally, the profile data of CRCP(Continuously Reinforced Concrete Pavement) sections on the same expressway were obtained and analyzed at the same time. The validity of the method developed for the slab curvature shape extraction is verified by comparing the result from the analysis of the profile data of CRCP sections with that from the analysis of the prof1Ie data of jointed concrete pavement sections.

• Korean Journal of Environmental Agriculture
• /
• v.42 no.4
• /
• pp.259-268
• /
• 2023

Rhodococcus sp. 3-2 strain has been reported to degrade benzimidazole-based pesticides, such as benomyl and carbendazim. Therefore, this study aimed to optimize culture medium composition and culture conditions to achieve cost-effective and efficient large-scale production of the Rhodococcus sp. 3-2 strain. The study identified that the optimal media composition for mass culture comprised 0.5% glucose, 0.5% yeast extract, 0.15% NaCl, 0.5% K₂HPO₄, 0.5% sodium succinate, and 0.1% MgSO₄. Additionally, a microbial agent was developed using a 1.5-ton fermenter, with skim milk (20%), monosodium glutamate (15%), and vitamin C (2%) as key components. The storage stability of the microbial agent has been confirmed, with advantages of low temperature conservation, which helps to sustain efficacy for at least six months. We also assessed the benomyl degradation activity of the microbial agent within field soil. The results revealed an over 90% degradation rate when the concentration of viable cells exceeded 2.65 × 10⁶ CFU/g after a minimum of five weeks had elapsed. Based on these findings, Rhodococcus sp. 3-2 strain can be considered a cost-effective microbial agent with diverse agricultural applications.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.20 no.3
• /
• pp.107-112
• /
• 2010

The Cu$(In_{1-x}Ga_x)Se_2$ is the absorber material for thin film solar cell with high absorption coefficient of $1{\times}10^5cm^{-1}$. In the case of CIGS, the movable energy band gap from $CuInSe_2$ (1.00 eV) to $CuGaSe_2$ (1.68 eV) can be acquired while controlling Ga contain ratio. Generally, the co-evaporator method have used for development and fabrication of the CIGS absorption layer. However, this method should need many steps and lengthy deposition time with high temperature. For these reasons, in this paper, a new growth method of CIGS layer was attempted to hydride vapor transport (HVT) method. The CIGS mixed-source material reacted for HCl gas in the source zone was deposited on the substrate after transporting to growth zone. c-plane $Al_2O_3$ and undoped GaN were used as substrates for growth. The characteristics of grown samples were measured from SEM and EDS.

• Horticultural Science & Technology
• /
• v.31 no.4
• /
• pp.512-516
• /
• 2013

Pear cultivar 'Sinhwa' (Pyrus pyrifolia var. culta Nakai) was originated from a cross between 'Niitaka' and Whasan' with the aims of improving the fruit quality and the traits of cultivation and of early maturing more than 'Whasan' cultivar at Pear Research Station of National Institute of Horticultural & Herbal Science, Rural Development Administration in 1995. 'Sinhwa' was preliminarily selected in 2004 and named in 2009. The tree shows vigorous growth habit and semi-spread characters like 'Niitaka'. Furthermore, it has a sufficient and well upkeep of the flower bud, so it can be more easily cultivated in orchards. In the flower characteristics, flowering time of 'Sinhwa' is $11^{th}$ April like as maternal parent 'Niitaka'. Also 'Sinhwa' has short of pollen grains, so it is need above two pollinizer cultivars. 'Sinhwa' is highly resistant to black leaf spot (Alternaria kikuchiana) and relatively strong to pear scab (Venturia nashicola) in field condition. The optimum harvest time is around Sep. $15^{th}$ in Naju, which is ahead of 'Whasan' about 10 days in the harvest period. The fruit shape is oblate and fruit skin color is yellowish-brown during harvesting time. The average weight of fruit is 627 g, and the soluble solids content is $13.0^{\circ}Brix$. The flesh is very soft and juicy, and renders good eating quality. Shelf life is about 30 days under the room temperature condition.