• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.167-176
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• 2015

The water quality of the Gulpo Stream flowing through Incheon, Bucheon, Seoul, and Kimpo is getting worse due to a slow flow rate and bank constructions by stream channelization as well as an inflow of pollutants from living-sewages and factory-sewages. Besides, a dry stream phenomenon caused by a lack of maintenance water upstream makes a self-purification system worse, and the water quality of the Gulpo Stream is currently at its lowest level. The accumulated sludge of the streambed is mostly formed by the deposition of particle pollutants due to the slow flow rate and an artificially straightened stream channel. This accumulated sludge adsorbs a great quantity of organic materials and heavy metals. Because of the internal contamination possibility by a re-gushing, even after the pollution source is removed, it can cause future water pollution. Without a total examination as previously recommended, it is considered difficult to accomplish practical efficiency. In conclusion, the management of periodic sediment management such as dredging would be necessary in the Gulpo Stream because sediment could be an internal pollution source of stream water under anaerobic conditions.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.204-213
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• 2012

The objectives of this research were to estimate nitrogen budgets in agriculture and livestock in 2010, and to evaluate nitrous oxide ($N_2O$) emission by a local government. Input-output budgets for nitrogen were categorized into two sections including agriculture and livestock. Fertilizer, deposition, fixation, compost, irrigation, and feed were used as the nitrogen inputs while crop production, crop uptake, denitrification, volatilization, leaching, compost, and ocean disposal were used as the nitrogen outputs. Annual nitrogen input and output for agriculture and livestock were 1,148,848 N ton/yr and 610,380 N ton/yr respectively indicating the decrease of the nitrogen input and output, compared to our previous researches in 2005 and 2008. Total nitrogen input in 16 local government was estimated resulting that $N_2O$ emission was the highest for Jeonnam (2,574 ton/yr) and the lowest for Seoul (7 ton/yr).

• Journal of Animal Science and Technology
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• v.57 no.5
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• pp.17.1-17.6
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• 2015

The present study investigated the nutritional and economic suitability of cashew reject meal (full fat and defatted) as replacement for groundnut cake (GNC) in the diets of laying chickens. A total of eighty four brown shavers at 25 weeks of age were randomly allotted into seven dietary treatments each containing 6 replicates of 2 birds each. The seven diets prepared included diet 1, a control with GNC at $220gkg^{-1}$ as main protein source in the diet. Diets 2, 3 and 4 consist of gradual replacement of GNC with defatted cashew reject meal (DCRM) at 50%, 75% and 100% on weight for weight basis respectively while diets 5, 6 and 7 consist of gradual inclusion of full fat cashew reject meal (FCRM) to replace 25%, 35% and 50% of GNC protein respectively. Each group was allotted a diet in a completely randomized design in a study that lasted eight weeks during which records of the chemical constituent of the test ingredients, performance characteristics, egg quality traits and economic indicators were measured. Results showed that the crude protein were 22.10 and 35.4% for FCRM and DCRM respectively. Gross energy of DCRM was 5035 kcal/kg compared to GNC, 4752 kcal/kg. Result of aflatoxin $B_1$ revealed moderate level between 10 and $17{\mu}g/Kg$ in DCRM and GNC samples respectively. Birds on control gained 10 g, while those on DCRM and FCRM gained about 35 g and 120 g respectively. Feed intake declined (P < 0.05) with increased level of FCRM. Hen day production was highest in birds fed DCRM, followed by control and lowest value (P < 0.05) was recorded for FCRM. No significant change (P > 0.05) was observed for egg weight and shell thickness. Fat deposition and cholesterol content increased (P > 0.05) with increasing level of FCRM. The cost of feed per kilogram decreased gradually with increased inclusion level of CRM. The prediction equation showed the relative worth of DCRM compared to GNC was 92.3% whereas the actual market price of GNC triples that of DCRM. It was recommended that GNC could be completely replaced by DCRM in layer's diets in regions where this by product is abundant. However, FCRM should be cautiously used in diets of laying chickens.

• Journal of agriculture & life science
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• v.45 no.2
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• pp.35-41
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• 2011

This study was carried out to investigate the relation of acid depositions and chlorophyll concentration in the Pinus thunbergii leaves. pH of throughfall in Pinus thunbergii forest was 4.20 at industrial sites, and 4.87 at urban sites. Total chlorophyll concentration in leaves were 0.5984 at industrial sites, and 0.6784 at urban sites. The average $SO_2$ concentration in air was 0.029ppm at industrial sites, and 0.011ppm at urban sites. Correlation between chlorophyll concentration in the Pinus thunbergii leaves and acid depositions was pH (r=-0.8769), ${NO_3}^-$ (r=0.6983), ${SO_4}^{2-}$ (r=0.8929), $SO_2$ (r=0.8738), and $NO_2$ (r=0.8523) (p<0.001). respectively. The estimation equation of chlorophyll concentration in the Pinus thunbergii leaf (Y) were given by Y=4.8979 + 0.7698pH + $0.8412{SO_4}^2$ + $0.8673SO_2$, + $0.8767NO_2$+ $0.8767{NO_3}^-$ ($r^2$=0.8873), which coefficients of determination was 0.88.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1207-1213
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• 2011

This study was conducted to assess $N_2O$ emissions in agricultural soils of Korea. According to 1996 and 2006 IPCC (Intergovernmental Panel on Climate Change) methodology, $N_2O$ emission was calculated the sum of direct emission ($N_2O_{DIRECT}$) and indirect emission ($N_2O_{INDIRECT}$). To calculate $N_2O$ emissions, emission factor was used default of IPCC and activity data was used the food, agricultural, forestry and fisheries statistical yearbook of MIFAFF (Ministry for Food, Agriculture, Forestry and Fisheries). It was emitted 8,608 $N_2O$ Mg resulted from direct emission by application of chemical fertilizer and animal manure, input in n-fixation crops and input of crop residues and emissions converted $N_2O$ into $CO_2$ equivalent was 2,668 $CO_2$-eq Gg. Indirect emission as $N_2O_{(G)}$ (atmospheric deposition of $NH_3$ and $NO_X$) and $N_2O_{(L)}$ (leaching and runoffs) were 4,567 and 6,013 $N_2O$ Mg and emissions converted $N_2O$ into $CO_2$ equivalent were 1,416 and 1,864 $CO_2$-eq Gg, respectively. Total $N_2O$ emission in Korea agricultural soil in 2009 was 5,948 $CO_2$-eq Gg.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.821-827
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• 2018

In devices used for re-forming osteoblasts to treat osteoporosis, a magnetic field is applied from the outside of the bone, and the minerals contained in the bone are aligned in a certain direction and undergo precessional motion. When a $90^{\circ}$ RF pulse is applied by using an RF coil, protons of minerals are brought to an excited state, and phosphorus activity promoting the deposition of osteoblasts in the bone is increased, thereby reshaping the bone. Miniaturizing the RF coil that generates a signal corresponding to the harmonic of the precessional motional frequency by means of the $90^{\circ}$ RF pulse can drastically reduce the overall size of the bone reshaping system. In this study, we propose a methodology for the miniaturization of the RF coil that can be used for osteoblast re-formation using a bone reshaping system. The capacitance of the designed RF coil is 25 pF, the inductance is approximately 100 nH, and the resonance frequency is 96 MHz. The radius of the end ring of the designed RF coil is 18 cm, and the total length of the leg is $2{\times}11.6cm$. The performance of the coil is verified through post-design measurement.

• Korean Journal of Heritage: History & Science
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• v.45 no.1
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• pp.218-231
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• 2012

A total of 126 fossil scaphopods (121 specimens from the Hagjeon Formation and 5 specimens from the Duho Formation) were found from the Cenozoic strata, Hagjeon and Duho Formations, Pohang Basin, Korea. Five species belonging two genera (Fissidentalium yokoyamai, F. sp. A, B, and Rhabdus sp. A, B) were classified: the most dominant species is Fissidentalium yokoyamai. The species of Fissidentalium yokoyamai is characterized by curved shell (accuration=3.90%) and very closely spaced longitudinal ribs on shell surfaces, while the species of Rhabdus is a nearly straight shell characterized by concentric growth lines without longitudinal ribs. Identification of two genera is somewhat easy due to such morphological differences but classification at generic level is hard because diagnostic features (e.g., cross section and apical structure) are lost in the most specimens. Consequently, except for Fissidentalium yokoyamai, the rest were classified temporarily as F. sp. A, B, and Rhabdus sp. A, B. Two types of preservation state were recognized: one is three-dimensionally preserved specimen (3D specimen) and the other is compressed specimen. Internal parts of the 3D specimen is filled with clastic sediments identical to the surrounding sediments of the shells, which is not observed in the compressed specimens. It is, thus, concluded that the 3D fossils were originally empty but internal cavity were immediately filled with the sediments, which may have protect from the compaction due to pressure during deposition of the gravelly to coarse sandstone of the Hagjeon Formation.

• Animal Bioscience
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• v.35 no.5
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• pp.730-739
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• 2022

Objective: This study investigated the effects of dietary n-6:n-3 polyunsaturated fatty acid (PUFA) ratio on growth performance, blood indexes, tissue fatty acid composition and the gene expression in finishing pigs. Methods: Seventy-two crossbred ([Duroc×Landrace]×Yorkshire) barrows (68.5±1.8 kg) were fed one of four isoenergetic and isonitrogenous diets with n-6:n-3 PUFA ratios of 2:1, 3:1, 5:1, and 8:1. Results: Average daily gain, average daily feed intake and gain-to-feed ratio had quadratic responses but the measurements were increased and then decreased (quadratic, p<0.05). The concentrations of serum triglyceride, total cholesterol and interleukin 6 were linearly increased (p<0.05) with increasing of dietary n-6:n-3 PUFA ratio, while that of high-density lipoprotein cholesterol tended to decrease (p = 0.062), and high-density lipoprotein cholesterol:low-density lipoprotein cholesterol ratio and leptin concentration were linearly decreased (p<0.05). The concentration of serum adiponectin had a quadratic response but the measurement was decreased and then increased (quadratic, p<0.05). The proportion of C18:3n-3 was linearly decreased (p<0.05) in the longissimus thoracis (LT) and subcutaneous adipose tissue (SCAT) as dietary n-6:n-3 PUFA ratio increasing, while the proportion of C18:2n-6 and n-6:n-3 PUFA ratio were linearly increased (p<0.05). In addition, the expression levels of peroxisome proliferator-activated receptor gamma (PPARγ) and lipoprotein lipase in the LT and SCAT, and adipocyte fatty acid binding protein and hormone-sensitive lipase (HSL) in the SCAT had quadratic responses but the measurements were increased and then decreased (quadratic, p<0.05). The expression of HSL in the LT was linearly decreased (p<0.05) with increasing of dietary n-6:n-3 PUFA ratio. Conclusion: Dietary n-6:n-3 PUFA ratio could regulate lipid and fatty acid metabolism in blood and tissue. Reducing dietary n-6:n-3 PUFA ratio (3:1) could appropriately suppress expression of related genes in PPARγ signaling, and result in improved growth performance and n-3 PUFA deposition in muscle and adipose tissue in finishing pigs.

• Korean Journal of Optics and Photonics
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• v.33 no.2
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• pp.74-83
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• 2022

The entire process, from the raw material to the final system qualification test, has been developed to fabricate a large-diameter, lightweight reflective-telescope system for a satellite observation. The telescope with 3 anastigmatic mirrors has an aperture of 700 mm and a total mass of 66 kg. We baked a silicon carbide substrate body from a carbon preform using a reaction sintering method, and tested the structural and chemical properties, surface conditions, and crystal structure of the body. We developed the polishing and coating methods considering the mechanical and chemical properties of the silicon carbide (SiC) body, and we utilized a chemical-vapor-deposition method to deposit a dense SiC thin film more than 170 ㎛ thick on the mirror's surface, to preserve a highly reflective surface with excellent optical performance. After we made the SiC mirrors, we measured the wave-front error for various optical fields by assembling and aligning three mirrors and support structures. We conducted major space-environment tests for the components and final assembly by temperature-cycling tests and vibration-shock tests, in accordance with the qualifications for the space and launch environment. We confirmed that the final telescope achieves all of the target performance criteria.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.871-881
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• 2023

This study investigates the geomorphic changes and Bed Relief Index of the river downstream of the Yeongju Dam by Nays2DH, a two-dimensional numerical model, in order to grasp the dynamics of the downstream river while applying various flow patterns such as pulse discharge. It shows that the geomorphic and the bed elevations changes are the largest under the condition of the normalized pulse discharge. The total change in the riverbed is 29.88 m for uniform flow, 27.46 m for normalized hydrograph, 29.63 m for pulse flow and 31.87 m for pulse flow with normalized hydrograph which result in the largest variation in scour and deposition. The Bed Relief Index (BRI) increases with time under conditions of uniform flow, pulse flow and pulse flow with normalized hydrograph. However, BRI increased rapidly until 30 hrs after the peak flow (14 hrs), but decreased from 56 hrs under the condition of normalized hydrograph. Therefore, the condition of normalized hydrograph gives greater dynamics than the condition of a single flood or constant flow, and the dynamics increase downstream than upstream, resulting in an effect on improving the environment of the river downstream of the dam.