• Proceedings of the Korean Magnestics Society Conference
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• 2005.06a
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• pp.158-159
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• 2005

• Journal of the Korean Magnetics Society
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• v.22 no.6
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• pp.221-227
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• 2012

High performance permanent magnets have become the subject of considerable attention because of the potential applications in the traction motors of hybrid and electric vehicles and wind generators. Nd-Fe-B magnets have attracted considerable interest due to a large maximum energy product. However, Nd-Fe-B magnet cannot be used in high temperature (${\sim}200^{\circ}C$) applications due to the thermal degradation of coercivity. Therefore, the development of high coercivity Nd-Fe-B permanent magnet is a challenging issue. In case of high coercivity Nd-Fe-B permanent magnet, an increment in the intrinsic coercivity can be easily achieved by substituting Nd atoms with Dy or Tb atoms. However, these heavy rare-earth elements are known to cause a decrease in remanence due to the antiferromagnetic coupling between Dy and Fe atoms. In addition, Dy is relatively expensive and being limited in quantity. Hence, a new technology that can increase the coercivity of Nd-Fe-B sintered magnet using only a small amount, or even, no amount of heavy rare-earth elements is being investigated. This article describes the research trend in reducing the heavy rare-earth elements in Nd-Fe-B magnets.

• Korean Journal of Agricultural Science
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• v.19 no.2
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• pp.269-272
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• 1992

A new single glutinous maize hybrid "Huin Chal 1" was developed at the Genetics and Breeding Lab., Dept. of Agron., College of Agriculture, Chungnam National University. Parents for the hybrid were all derived from Korean indigenous maize lines which were collected in 1980s. One of the parental inbred lines was originated from Bosung, Chonnam province and other inbred line was from Jewon, Chungbuk province. Both inbreds were developed by ear-to-row selection method through selling and named as Bosung and Jewon, respectively. Performace tests for the hybrid which was produced between Bosung and Jewon have been conducted five times including one test at Crop Experiment Station, Rural Development Administration. From the previous performance tests, the hybrid was recognized as high yielding hybrid with good agronomic characteristics and we named the hybrid as Huin Chal 1., and hereby we report the agronomic characters of the newly developed hybrid.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.7-13
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• 2010

We report a hybrid DPSSL with a pulse parameter variable LD seed, all-fiberized polarization-maintained pulsed Yb-doped fiber preamplifier chains, and a bulk Nd:$YVO_4$ power amplifier. Pulse parameter of LD seed was controlled by direct current modulation. The hybrid DPSSL generates 1064 nm laser pulses with an average power of 40W, a pulse duration of 20-40ns, and a repetition rate of 100-500kHz.

• 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 Agricultural Science
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• v.40 no.2
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• pp.87-91
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• 2013

The major characteristics of the developed corn hybrids were compared at each different planting time; 1st time(April 28) and 2nd time(August 20), respectively. Among traits surveyed, stem height showed highly at 1st time than 2nd, while ear height, stem diameter and ear length were similar at two times. Sugar content of the used hybrids showed highly at 2nd planting time than 1st. Pericarp thickness was also high at 2nd planting time. Especially, among hybrids CNU99 was the highest in stem height and ear length, CNU11 and CNU56 were high in sugar content, and CNU51 and CNU124 were thiner than other hybrids in pericarp thickness. Accordingly, these hybrids will be planted and recognized in 2nd yield trial for superior corn hybrid selection.

• Journal of Powder Materials
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• v.17 no.1
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• pp.23-28
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• 2010

HDDR treated anisotropic Nd-Fe-B powders have been widely used for the sheet motors and the sunroof motors of hybrid or electric vehicles, due to their excellent magnetic properties. Microstructural alignment of HDDR treated powders are mostly depending on the hydrogen reaction in disproportionation step, so the specific method to control hydrogenation reaction is required for improving magnetic properties. In disproportionation step, hydrogenation pressure and reaction time were controlled in the range of 0.15~1.0 atm for 15~180 min in order to control the micorstructural alignment of $Nd_2Fe_{14}B$ phase and, at the same time, to improve remanence of HDDR treated magnet powders. In this study, we could obtain a well aligned anisotropic Nd-Fe-B-Ga-Nb alloy powder having high remanence of 12 kG by reducing hydrogen pressure down to 0.3 atm in disproportionation step.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1634-1639
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• 2015

Cytochrome P450 hydroxylase (CYP) in actinomycetes plays an important role in the biosynthesis and bioconversion of various secondary metabolites. Two unique CYPs named CYP-sb21 and CYP-pa1, which were identified from Sebekia benihana and Pseudonocardia autotrophica, respectively, were proven to transfer a hydroxyl group at the 4^th or 9^th N-methyl leucine position of immunosuppressive agent cyclosporin A (CsA). Interestingly, these two homologous CYPs showed different CsA regio-selectivities. CYP-sb21 exhibited preferential hydroxylation activity at the 4^th position over the 9^th position, whereas CYP-pa1 showed the opposite preference. To narrow down the CYP domain critical for CsA regio-selectivity, each CYP was divided into four domains, and each domain was swapped with its counterpart from the other CYP. A total of 18 hybrid CYPs were then individually tested for CsA regio-selectivity. Although most of the hybrid CYPs failed to exhibit a significant change in regio-selectivity in the context of CsA hydroxylation, hybrid CYP-pa1 swapped with the second domain of CYP-sb21 showed a higher preference for the 9^th position. Moreover, hybrid CYPsb21 containing seven amino acids from the 2nd domain of CYP-pa1 showed higher preference for the 4^th position. These results imply that the 2nd domain of CsA-specific CYP plays a critical role in CsA regio-selectivity, thereby setting the stage for biotechnological application of CsA regio-selective hydroxylation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.12 s.103
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• pp.1186-1193
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• 2005

In this paper, a new 3 dB branch line hybrid using asymmetric spiral-shaped defected ground structure(DGS) microstrip is proposed. The proposed branch line hybrid suppresses the 2nd and the 3rd harmonic component effectively. Also a DGS $\lambda$/4 bias line that can suppress high frequency harmonics as well as low frequency intermodulation component is proposed. With the harmonic termination tuner using the proposed hybrid and the harmonic blocking bias line, the 2nd and the 3rd harmonic components of the fabricated amplifier that operated in IMT-2000 basestation transmitting band were suppressed up 25 dB and 27 dB, respectively. The proposed harmonic load-pull setup of amplifier is more easily accomplished with proposed circuits than the previous.

• Journal of Broadcast Engineering
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• v.16 no.6
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• pp.969-976
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• 2011

In this paper, a terrestrial transmission system is proposed for the next generation digital television (DTV) system by applying a hybrid multi-input multi-output (MIMO) technology based on linear dispersion codes (LDCs). The digital video broadcasting-2nd generation terrestrial (DVB-T2) system adopted a space time block code (STBC) for improving receive performance. However, the data rate of STBC is not increased in proportion to the transmitter. The hybrid STBC scheme utilizes several STBC transmission blocks for increasing data rate. It is possible to increase the data rate and performance in the receiver by utilizing LDC. The performances of the proposed and conventional hybrid STBC schemes are evaluated through computer simulations.