• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.95-96
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• 1998

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.179.1-179
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• 2002

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1398-1402
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• 1998

• BMB Reports
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• v.39 no.3
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• pp.297-303
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• 2006

As lipolytic enzymes, GDSL lipases play an important role in plant growth and development. In order to identify their functions and roles, the full-length cDNA of a GDSL lipase gene, designated BnLIP2, was isolated from Brassica napus L. BnLIP2 was 1,300 bp long, with 1,122 bp open reading frame (ORF) encoding 373 amino acid residues. Sequence analysis indicated that BnLIP2 belonged to GDSL family. Southern blot analysis indicated that BnLIP2 belonged to a small gene family in rapeseed genome. RT-PCR analysis revealed that BnLIP2 was a tissue-specific expressing gene during reproductive growth and strongly expressed during seed germination. BnLIP2 expression could not be detected until three days after germination, and it subsequently became stronger. The transcript of this gene was deficient in root of seedlings growing at different stages. When juvenile seedlings were treated by methyl jasmonate (MeJ), salicylic acid (SA) and naphthalene acetic acid (NAA), BnLIP2 expression could not be induced in root. Our study implicates that BnLIP2 probably plays an important role in rapeseed germination, morphogenesis, flowering, but independent of root growth and development.

• Bulletin of the Korean Mathematical Society
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• v.52 no.4
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• pp.1133-1138
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• 2015

In 1956, $Je{\acute{s}}manowicz$ conjectured that, for any positive integer n and any primitive Pythagorean triple (a, b, c) with $a^2+b^2=c^2$, the equation $(an)^x+(bn)^y=(cn)^z$ has the unique solution (x, y, z) = (2, 2, 2). In this paper, under some conditions, we prove the conjecture for the primitive Pythagorean triples $(a,\;b,\;c)=(4k^2-1,\;4k,\;4k^2+1)$.

• Journal of the Korean Ceramic Society
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• v.40 no.4
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• pp.346-349
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• 2003

Microwave dielectric characteristics and physical properties of the new Zr$_{1-x}$ (Bn$_{1}$3/Nb$_{2/3}$)xTi $O_4$ (0.2$\leq$x$\geq$ 1.0) system have been investigated as a function of the amount of Bn$_{1}$3/Nb$_{2/3}$ $O_2$substitution. With increasing Bn$_{1}$3/Nb$_{2/3}$ $O_2$ content (x), two phase regions were observed: $\alpha$-Pb $O_2$ solid solution (x<0.4), mixture of the rutile type Zn$_{1}$3/Nb$_{2/3}$Ti $O_4$ and the $\alpha$-Pb $O_2$ solid solution (x$\geq$0.4). In the$\alpha$-Pb $O_2$solid solution region below x<0.4, the Q.f$_{0}$ value sharply increased and the Temperature Coefficient of the Resonant Frequency(TCF) decreased with increasing Bn$_{1}$3/Nb$_{2/3}$ $O_2$ contents while dielectric constant (K) showed nearly same value. In the mixture region above x$\geq$4, the dielectric constant and TCF increased with increasing Bn$_{1}$3/Nb$_{2/3}$ $O_2$ content. Zr$_{1-x}$ (Zn$_{1}$3/Nb$_{2/3}$)xTi $O_4$ materials have excellent microwave dielectric properties with K=44.0, Q.f$_{0}$ : 41000 GHz and TCF =-3.0 ppm/$^{\circ}C$ at x=0.35.=0.35. x=0.35.=0.35.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.1-7
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• 2009

Resistive heating sources are widely used to prepare thin films by vapor deposition because they are cheap, and easy to install and handle in vacuum system. Graphite is one of materials used to make the resistive heating source, but until now only limited applications have been possible as it reacts easily with evaporating materials at high temperature. In this study, evaporation characteristics of aluminum have been investigated by using graphite boat thermally treated with BN powder. The employed graphite boat has been prepared by spray-coating BN power onto the cavity surface of the boat and thermal treatment with aluminum in vacuum at the temperature of more than $1400^{\circ}C$. The voltage-current characteristics as well as resistivity changes of the graphite boat have been investigated during aluminum evaporation according to the applied voltage and time. The evaporation aspect has been picturized during flash evaporation for 40 seconds based on the characterization results. The evaporation rate of the graphite boat has been compared with that of BN boat. The graphite boat showed some different characteristics compared with BN boat, in that the evaporation occurred at the last stage of flash evaporation. The film appearance according to the applied voltage has been compared, and also the reflectance of the resulting film has been investigated according to the film thickness. It has been found that the graphite boat thermally treated with BN powder can be used for aluminum evaporation without problem.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.1
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• pp.59-65
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• 1993

The boron-doped polycrystalline silicon films which can be used in pressure sensors were fabricated in a high-vacuum resistance heating evaporator. Poly-Si films were deposited on quartz substrates at various temperatures and the boron was doped to the silicon film in a diffusion furnace using BN wafer. The silicon films deposited at $500^{\circ}C$ was amorphous, began to show crystalline at $600^{\circ}C$, and became polycrystalline at $700^{\circ}C$. After doping boron at $900^{\circ}C$for 10 minutes, the resistivity of the films was in the range of $0.1{\Omega}cm~1.5{\Omega}cm$, the boron density was $9.4\times10^{15}~2.1\times{10}^{17}cm^{-3}$, and the grain size was $107{\AA}~191{\AA}$.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.60-60
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• 2015

Nanosheets of graphene and related 2D materials have attracted much attention due to excellent physical, chemical and mechanical properties. Single-layer graphene (SLG) was first synthesized by Blakely et al in 1974 [1]. Following his achievements, we initiated the growth and characterization of graphene and h-BN on metal substrates using surface segregation and precipitation in 1980s [2,3]. There are three important steps for nanosheet growth; surface segregation of dopants, surface reaction for monolayer phase, and subsequent 3-D growth (surface precipitation). Surface phase transition was clearly demonstrated on C-doped Ni(111) by in situ XPS at elevated temperatures [4]. The growth mode was clarified by inelastic background analysis [5]. The surface segregation approach has been applied to C-doped Pt(111) and Pd(111), and controllable growth of SLG has been demonstrated successfully [6]. Recently we proposed a promising method for producing SLG fully covering an entire substrate using Ni films deposited on graphite substrates [7]. A universal method for layer counting has been proposed [8]. In this paper, we will focus on the effect of competitive surface-site occupation between carbon and other surface-active impurities on the graphene growth. It is known that S is a typical impurity of metals and the most surface-active element. The surface sites shall be occupied by S through surface segregation. In the case of Ni(110), it is confirmed by AES and STM that the available surface sites is nearly occupied by S with a centered $2{\times}2$ arrangement. When Ni(110) is doped with C, surface segregation of C may be interfered by surface active elements like S. In this case, nanoscopic characterization has discovered a preferred directional growth of SLG, exhibiting a square-like shape (Fig. 1). Also the detailed characterization methodologies for graphene and h-BN nanosheets, including AFM, STM, KPFM, AES, HIM and XPS shall be discussed.

• Korean Journal of Materials Research
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• v.8 no.11
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• pp.1020-1025
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• 1998

Irradiation-induced changes in mechanical properties and magnetic parameters were measured and compared to explore possible correlations for Mn-Mo-Ni low alloy steel surveillance specimens which were irradiated to a neutron fluence of $2.3\times10^{19}n/cm^2$(E>1.0MeV) in a typical pressurized water reactor environment at about $288^{\circ}C$. For mechanical property parameters, microvickers hardness, tensile and Charpy impact test were performed and Barkhausen noise amplitude, coercivity, remanence, maximum induction were measured for magnetic parameters. respectively. Results of mechanical property measurements showed an increase in yield and tensile strength, microvickers hardness. 41J indexed $RT_{NDT}$ and a decrease in upper shelf energy irrespective of base and weld metals. However, in the case of tensile properties, the changes in weld metal were negligible compared to the base metal. In the case of magnetic measurements, it is found that magnetic remanence, BN amplitude. BN energy have dropped significantly but coercivity(H,) has increased rapidly after irradiation. In this study. the measurements conducted on surveillance specimens of Mn-Mo-Ni low alloy steel showed that there were strong correlations between mechanical properties and magnetic properties.