• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.77-82
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• 2011

The use of soft magnetic materials have been increasing in the various industrial fields according to the increasing demand for high performance, automatic, miniaturing equipments in the recent our life. In this study, we investigated the effect of factors on the core loss and magnetic properties of electrical steel and soft magnetic composites. Furthermore, we reviewed the major efforts to reduce the core loss and improve the soft magnetic properties in the two main soft magnetic materials. Domain purification which results from reduced density of defects in cleaner electrical steels is combined with large grains to reduce hysteresis loss. The reduced thickness and the high electrical conductivity reduce the eddy current component of loss. Furthermore, the coating applied to the surface of electrical steel and texture control lead to improve high permeability and low core loss. There is an increasing interest in soft magnetic composite materials because of the demand for miniaturization of cores for power electronic applications. The SMC materials have a broad range of potential applications due to the possibility of true 3-D electromagnetic design and higher frequency operation. Grain size, sintering temperature, and the degree of porosity need to be carefully controlled in order to optimize structure-sensitive properties such as maximum permeability and low coercive force. The insulating coating on the powder particles in SMCs eliminates particle-to-particle eddy current paths hence minimizing eddy current losses, but it reduces the permeability and to a small extent the saturation magnetization. The combination of new chemical composition with optimum powder manufacturing processes will be able to result in improving the magnetic properties in soft magnetic composite materials, too.

• The Journal of the Petrological Society of Korea
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• v.26 no.4
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• pp.311-325
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• 2017

Peridotite xenoliths in middle Miocene alkaline basalt from the Mt. Baekdu area are mainly anhydrous spinel lherzolites, displaying coarse-grained protogranular texture. These xenoliths have late-stage secondary orthopyroxene replacing olivine as the metasomatic mineral and glass formed along the grain boundaries. The studied xenoliths are characterized by the high $Mg{\sharp}[=100{\times}Mg/(Mg+Fe_{total})$ atomic ratio] of olivine, orthopyroxene and clinopyroxene (89~92) and the $Cr{\sharp}[=100{\times}Cr/(Cr+Al)$ atomic ratio] of spinel (10~29). Based on major-element data, the studied xenoliths are similar to those from the abyssal peridotites. Clinopyroxenes of the xenoliths are mostly enriched in incompatible trace elements, exhibiting two types of REE patterns: (1) LREE-depleted with $(La/Yb)_N$ of 0.1~0.2 and $(La/Ce)_N$ of 0.4~0.8. (2) LREE enriched with $(La/Yb)_N$ of 2.2~3.8 and $(La/Ce)_N$ of 1.2~1.6. The calculated equilibrium temperatures and oxygen fugacities resulted in $920{\sim}1050^{\circ}C$ and ${\Delta}fO_2(QFM)=-0.8{\sim}0.2$, respectively. It is suggested that the Mt. Baekdu peridotite xenoliths represent residues left after variable degrees of melt extraction(less than 15 vol%), which was subsequently subjected to different degrees of modal/cryptic metasomatism by silica- and LREE-enriched fluids (or melts).

• The Korean Journal of Quaternary Research
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• v.17 no.1
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• pp.27-37
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• 2003

The Neolithic relics containing sedimentary deposits have been found in the Moonamni coastal zone of the East Sea, Korea. The purpose of this research is to establish the late Quaternary stratigraphy of the coastal dune deposit and to elucidate its depositional environment of the Neolithic-site sediments on the basis of analytical properties of grain size population and mineralogy of the sediments. As a result, the vertical sections of the sediments from three trenches are characterized by three major stratigraphic depositional units of Unit 3, Unit 2 and Unit 1 in ascending order. Unit 3 and 2 can be further divided into tow sub-units. Unit 3 is composed of massive sands in the lower part and muddy sand in the upper part. It is considered that the Unit 3 is a typical dune deposit showing well-sorted sands. Unit 2 is characterized by the cross-bedding, and include archaeological remains such as pottery shards. This unit can be further divided into two sub-units of muddy sand in the lower part and sand in the upper part. Unit 1 occupies the top section and consists of modem dune sediment. The Neolithic cultural remains would be accumulated in the coastal dune area in relation to dynamic condition of beach system under the high stand of Holocene sea-level at about 7,800∼6,500 yr B.P. or so.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.133-138
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• 2010

This study was conducted to analysis a major cause of rice yield reduction in 4 research points, 1, 2, 3, and 5km, from coastline in the East Sea. There were great changes of temperature in each research point, though the average temperature a day was no difference between each research point. Each temperature in 1, 2, and 3km research points was 8, 7, and $4^{\circ}C$ lower than in 5km when cold salty wind was generated due to cold pool. As it was close in coastline, its soil was abundant sand components, little silt and clay soil components and lacking in cation exchange capacity(CEC). And plant height became a smaller, heading date was delayed for 3～4 days, and dry weight was reduced. Also, it was to be down percent of fertile grain. As cultivation site was close in seaside, its decline was larger because of reduction of panicle number per hill. It was "Samdeogbyeo" that was variety adapted in cold salty wind, having yield potential more than 90% in 2km.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.332-335
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• 2008

"Hwangkeumbora" is a new japonica rice cultivar developed from a three way cross of Jinbubyeo, Odaebyeo, Fukei126 at Honam Agricultural Reaserch Institute (HARI), NICS, RDA, in 2006. This cultivar has about 110 days growth duration from transplanting to harvesting under Korean climate condition. The milled kernel of "Hwangkeumbora" is translucent with non- glutinous endosperm. Amylose content of "Hwangkeumbora" is about 19.3%. "Hwangkeumbora" has better palatability of cooked rice compared with "Odaebyeo" and shows high resistant reaction to the blast, but susceptible to major diseases and insect pests. The milled rice yield of "Hwangkeumbora" is about 5.37 MT/ha under the standard fertilizer level of the ordinary transplanting cultivation. "Hwangkeumbora" would be adaptable for ordinary transplanting in northern plain, mid-mountainous, southern mountainous of Korea.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.645-648
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• 2009

"Deuraechan" is a new japonica rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2008. This variety was derived from a three way cross Iksan438, YR19105Acp222 and Milyang165. This variety has about 122 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 76 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderately resistance to blast, resistance to bacterial blight pathogen races from $K_1$ to $K_3$, and Rice stripe virus, but susceptible to other major diseases and insect pests. The milled rice of "Deuraechan" has high Quality, midium short grain. The milled rice yield of this variety is about 6.52 MT/ha in local adaptability test for three years. "Deuraechan" would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.314-317
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• 2008

"Dami" is a new japonica rice variety developed and registered by the rice breeding team of Honam Agricultural Research Institute, NICS, RDA in 2006. This variety was derived from a cross between Iksan438 with lodging tolerance and high yield potential, and Iksan426 This variety has about 122 days of growth duration from transplanting to harvesting in Honam and Youngnam plain of Korea. It is about 83 cm in culm length and tolerance to lodging. In reaction to biotic stresses, it shows moderately resistance to blast, and resistance to bacterial blight pathogen races from $K_1$ to $K_3$, but susceptible to other major diseases and insect pests. The milled rice of "Dami" has high Quality, midium short grain. The milled rice yield of this variety is about 5.92 MT/ha in local adaptability test for three years. "Dami" would be adaptable to Middle plain, Honam plain and Youngnam plain area of Korea.

• Journal of Environmental Impact Assessment
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• v.28 no.5
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• pp.457-470
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• 2019

This study aims to present the characteristics of marine physics, water quality, and sediment quality around offshore wind farm near the Gochang and Buan sea areas through the analysis of monitoring data. The relationships between suspended solid and wave height as well as suspended solid and flow velocity were analyzed. We found that Correlation Coefficient values of 0.61~0.69 between wave height and suspended solid, and suspended solid concentration reaches 75 mg/L or higher when wave height of more than 1m occurred in the spring (1 month). The water quality index (WQI) was used to identify the status of the water quality in the study area. Most of the measured points were rated first grade (very good). The variation of chlorophyll-a was relatively hight compared to the other criteria, indicating that it is a major factor affecting the quality index. In the sediment column, all heavy metals were detected below the Threshold Effects Level(TEL), and ignition loss and grain size show a positive correlation.

• Korean Journal of Plant Resources
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• v.17 no.3
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• pp.304-313
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• 2004

This study was conducted to find out the scientific maize breeding protocol for developing high performing single cross hybrid using introduced U.S. elite inbred lines; the pattern of inheritance, heterosis and heritabilities of six agronomic traits were studied in the progenies derived from five crosses (Mo17/B14A, Va85/B73, C103/ND203, FR35/Oh43, Wf9/A632). Among the five cross combinations, the cross combination of Mo17/B14A showed the highest heterosis for the most agronomic traits. Among 6 agronomic traits, the grain yield showed the highest heterosis effect in most cross combinations. Most of the agronomic traits in this study showed more than 50% heritability for six cross combinations, with an exception of the ear length trait. In conclusion, since Mo17/B14A showed excellent performance for most of the agronomic traits, these inbred lines were desirable combination and regarded as superior germ plasm sources for F1 hybrid development. The results of current studies will be utilized for developing high performing single cross hybrid from maize inbred lines, and will be used for the further genetic analysis of agronomic traits and maize breeding programs.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.452-455
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• 2008

"Baegseolchal" is a new Japonica type waxi rice variety developed and registered by the rice breeding team of Department of Rice and Winter Cereal Crop, NICS, RDA in 2007. This variety was derived from a across between Iksan435 which is highly tolerant to lodging and high yield potential, and Iksan425 which is resistance to multiple diseases. This variety has about 120 days of growth duration from transplanting to harvesting in middle, Honam and Youngnam plain of Korea. It is about 80 cm in culm length and tolerant to lodging. It is moderately resistant to blast, and resistance to bacterial blight pathogen races from $K_1$ to $K_3$, but susceptible to other major diseases and insect pests. "Baegseolchal" is midium-short grain and the milled rice exhibits high whiteness. The milled rice yield was about 5.37 MT/ha in local adaptability test for three years. "Baegseolchal" would be adaptable to plain areas south of the Chungnam Province of Korea.