• Journal of the Korean institute of surface engineering
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• v.29 no.4
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• pp.261-267
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• 1996

The characteristics and adhesion strength of TiN layer deposited by D. C. magnetron sputtering were investigated. Three types of TiN layers were deposited on STS304 stainless steel. Scratch tests were performed to determine the effect of deposition temperature, the thickness of coated TiN layer and the titanium inter-layer on the adhesion strength. TiN multilayer with titanium inter-layer showed the highest critical load in the deposition temperature range of $25^{\circ}C$ to $300^{\circ}C$. Adhesion strength of TiN multilayer with titanium inter-layer was raised from 15N to 20N by raising deposition temperature from $25^{\circ}C$ to $400^{\circ}C$. Adhesion strength was raised from 18N to 38N by increasing the thickness of outer layer of TiN multilayer from 2.1 $\mu\textrm{m}$ to 9.5 $\mu\textrm{m}$.

• Journal of the Korea Society of Computer and Information
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• v.16 no.8
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• pp.103-108
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• 2011

Generally, Miller-Rabin method has been the most popular primality test. This method arbitrary selects m at k-times from m=[2, n-1] range and (m,n)=1. Miller-Rabin method performs $k{\times}r$ times and reports prime as $m^d\;{\equiv}\;1(mod\;n)$ or $m^{2^rd}\;{\equiv}\;-1(mod n)$ such that n-1=$2^sd$, $0\;{\leq}\;r\;{\leq}\;s-1$. This paper suggests more simple primality test than Miller-Rabin method. This test method computes c=$p^{\frac{n-1}{2}}(mod\;n)$ for k times and reports prime as c=-1. The proposed primality test method reduces $k{\times}r$ times of Miller-Rabin method to k times.

• Journal of the Korean Mathematical Society
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• v.33 no.3
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• pp.669-677
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• 1996

Let $M_n$ be the $C^*$-algebra of all $n \times n$ matrices over the complex field, and $P[M_m, M_n]$ the convex cone of all positive linear maps from $M_m$ into $M_n$ that is, the maps which send the set of positive semidefinite matrices in $M_m$ into the set of positive semi-definite matrices in $M_n$. The convex structures of $P[M_m, M_n]$ are highly complicated even in low dimensions, and several authors [CL, KK, LW, O, R, S, W]have considered the possibility of decomposition of $P[M_m, M_n] into subcones.

• Journal of Sensor Science and Technology
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• v.16 no.6
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• pp.457-461
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• 2007

This paper describes the characteristics of poly (polycrystalline) 3C-SiC grown on $SiO_{2}$ and AlN substrates, respectively. The crystallinity and the bonding structure of poly 3C-SiC grown on each substrate were investigated according to various growth temperatures. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (full width half maximum) of XRD and FT-IR by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was $1100^{\circ}C$. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each substrate were investigated by XPS and Hall Effect, respectively. The chemical compositions of surface of poly 3C-SiC films grown on $SiO_{2}$ and AlN were not different. However, their electron mobilities were $7.65{\;}cm^{2}/V.s$ and $14.8{\;}cm^{2}/V.s$, respectively. Therefore, since the electron mobility of poly 3C-SiC films grown on AlN buffer layer was two times higher than that of 3C-SiC/$SiO_{2}$, a AlN film is a suitable material, as buffer layer, for the growth of poly 3C-SiC thin films with excellent properties for M/NEMS applications.

• Korean Journal of Mathematics
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• v.21 no.2
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• pp.151-159
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• 2013

An $L(j,k)$-labeling of a graph G is a vertex labeling such that the difference of the labels of any adjacent vertices is at least $j$ and that of any vertices of distance two is at least $k$ for given $j$ and $k$. The minimum span of all L(2, 1)-labelings of G is called the ${\lambda}$-number of G and is denoted by ${\lambda}(G)$. In this paper, we find a lower bound of the ${\lambda}$-number of the Cartesian product $K_m{\Box}C_n$ of the complete graph $K_m$ of order $m$ and the cycle $C_n$ of order $n$. In fact, we show that when $n{\geq}3$, ${\lambda}(K_4{\Box}C_n){\geq}7$ and the equality holds if and only if n is a multiple of 8. Moreover when $m{\geq}5$, ${\lambda}(K_m{\Box}C_n){\geq}2m-1$ and the equality holds if and only if $n$ is even.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.7-16
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• 2006

The present study evaluated effect of temperature on removals of organic matter (C), nitrogen (N) and phosphorus (P) in Modified-Dephanox (M-Dephanox) process, which is hybrid system, comparing with those of Modified-Ludzack Ettinger (MLE) under the suspended-growth bacteria, as control. M-Dephanox process was more stable than MLE process in the removal of C, N, P, especially in nitrification, as the temperature was decreased from $25^{\circ}C$ to $16^{\circ}C$. As the temperature was decreased from $25^{\circ}C$ to $16^{\circ}C$, the removal efficiency of $NH_4{^+}-N$ of M-Dephanox process was decreased by 3.8%, but that of MLE process decreased by 25.7%. T-N removal efficiency of M-Dephanox was higher than MLE process by 27.1% and 26.9% at $25^{\circ}C$ and $16^{\circ}C$ of temperature, respectively.

• Journal of the Korean institute of surface engineering
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• v.36 no.3
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• pp.229-233
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• 2003

Boron-Carbon-Nitrogen (B-C-N) system is an attractive ternary material since it has not only an extremely high hardness but also a number of other prominent characteristics such as chemical inertness, elevated melting point, and low thermal expansion. In this paper, the corrosion behavior of B-C-N thin films in aqueous solution was investigated B-C-N films with different composition were deposited on a platinum plate by magnetron sputtering in the thickness range of 150-280 nm. In order to understand effect of pH of solutions, $BC_{2.\;4}N$ samples were immerged in 1M HCl, 1M NaCl, and 1M NaOH solution at 298k, respectively. BCN samples with different carbon contents were exposed to 1M NaOH solutions to investigate effect of chemical composition on corrosion resistance. Corrosion rates of samples were measured by ellipsometry, From results, optical constant of $BC_{2,\;4}N$ films was found to be $N_2=2.110-0.295i$. The corrosion rates of $Bi_{1.\;0}C_{2.\;4}N_{1.\;0}$ films were NaOH>NaCl>HCl in orders. With increasing carbon content in B-C-N films, the corrosion resistance of B-C-N films was enhanced. The lowest corrosion rate was obtained for $B_{1.\;0}C_{4.\;4}N_{1.\;9}$ film.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.131-140
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• 1993

To study the corrosion fatigue begavior of T.M.C.P. steel, the rotary bending fatigue test with the change of concentration of NaCl solution was carried out. Fatigue life in the corrosion environment is decreased markedly in comparision with that in the air. Fatigue limit in the air was about 225 MPa. In case of 3.5% NaCl solution fatigue life could be expressed as .sigma./sub f/=10,392 * (N/sub f/)/sup -o.2923 . According to the paris's rule, crack growth rates could be expressed as da/dN=2.62.*10/sup -7/ .DELTA. K/sup 1.09/(3.5% NaCl solution), da/dN=1.95 *10/sup -7 .DELTA. K/sup 1.05/(1% NaCl solution), da/dN=2.62 * 10/sup -7/.DELTA./sup 0.72/(0.01% NaCl solution) with da/dN expressed in mm/cycle and .DELTA.K in MPa.GAMMA.m. The crack growth rate in the corrosion environment was highest under 3.5% NaCl solution.

• Korean journal of applied entomology
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• v.40 no.4
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• pp.277-294
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• 2001

Four new and two known species of soil nematodes belonging the order Dorylaimida are described and illustrated. Discolaimium gyeongiens n. sp. is 1.6~1.7 mm long, c=37~41, odontostyle 19~21$\mu\textrm{m}$ long and is characterized by having wider lip region and very short prerectum. Aporcelaimellus donghwaens n. sp. is 2.8~2.9mm long, c=40.0~4.5, odontostyle 19~20$\mu\textrm{m}$ long and is characterized by possessing shorter odontophore, presence of cardiac disc and conoid tail. Labronema korandus n. sp. is 2.2~2.3 mm long, c=68~81, odontostyle 27~28$\mu\textrm{m}$, spicule 61$\mu\textrm{m}$ long and is characterized by having continuous lip region, circular vulva and cylindrical tail. Zalophidera longus n. sp. is 4.1~4.4mm long, c=107~130, spear 80~93$\mu\textrm{m}$ long and is characterized by large sized body, spear and spear extension. Discolaimoides bulbiferous and Diphtherophora communis were reported here for the first time in Korea.

• Korean Journal of Mathematics
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• v.8 no.2
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• pp.155-162
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• 2000

For a sequence $\{{\eta}_m\}_m$ of unit vectors in $\mathbb{C}^n$, we consider the associated linear functional ${\omega}$ on the Cuntz algebra $\mathcal{O}_n$. We show that the restriction ${\omega}{\mid}_{UHF_n}$ is the product pure state of a subalgebra $UHF_n$ of $\mathcal{O}_n$ such that ${\omega}{\mid}_{UHF_n}={\otimes}{\omega}_m$ with ${\omega}_m({\cdot})$ < ${\cdot}{\eta}_m,{\eta}_m$ >. We study product pure states of UHF and obtain a concrete description of them in terms of unit vectors. We also study states of $UHF_n$ which is the restriction of the linear functionals on $O_n$ associated to a fixed unit vector in $\mathbb{C}^n$.