• Journal of Food Hygiene and Safety
• /
• v.28 no.4
• /
• pp.349-353
• /
• 2013

This study was performed to evaluate the bactericidal efficacy of Fumagari OPP$^{(R)}$, fumigation disinfectant, containing 20% ortho-phenylphenol against Staphylococcus aureus (S. aureus). In this research, efficacy test of fumigant against S. aureus was carried out according to French standard NF T 72-281. S. aureus working culture suspension number (N value), all of the colony numbers on the carriers exposed with the fumigant (n1, n2, and n3), the number of bacterial test suspentions by pour plate method (N1), the number of bacterial test suspentions by filter membrane method (N2) and the mean number of bacteria recovered on the control-carriers (T value) were obtained from the preliminary test. In addition, the reduction number of S. aureus exposed with the fumigant (d value) was calculated using T value, the mean number of bacteria in recovery solution (n'1) and the mean number of bacteria on carriers plated in agar (n'2). N value was $4.0{\times}10^8$ CFU/mL, and n1, n2, and n3 were higher than 0.5N1, 0.5N2 and 0.5N1, respectively. Additionally, T value was $3.4{\times}10^6$ CFU/mL. In the bactericidal effect of the fumigant, the d value was 6.43 logCFU/mL. According to the French standard for the fumigant, the d value for the effective bactericidal fumigant should be over than 5 logCFU/mL. The results indicated that Fumagari OPP$^{(R)}$ had an effective bactericidal activity against S. aureus, then the fumigant can be applied to disinfect food materials and kitchen appliances contaminated with pathogenic bacteria.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.1
• /
• pp.131-135
• /
• 2005

Gallium nitride (GaN) powders and nanowires were prepared by using tris(N,N-dimethyldithiocarbamato)gallium(III) (Ga(DmDTC)$_3$) and tris(N,N-diethyldithiocarbamato)gallium(III) (Ga(DeDTC)$_3$) as new precursors. The GaN powders were obtained by reaction of the complexes with ammonia in the temperature ranging from 500 to 1100 ${^{\circ}C}$. The process of conversion of the complexes to GaN was monitored by their weight loss, XRD, and $^{71}$Ga magic-angle spinning (MAS) NMR spectroscopy. Most likely the complexes decompose to $\gamma$ -Ga$_2$S$_3$ and then turn into GaN via amorphous gallium thionitrides (GaS$_x$N$_y$). The reactivity of Ga(DmDTC)$_3$ with ammonia was a little higher than that of Ga(DeDTC)$_3$. Room-temperature photoluminescence spectra of asprepared GaN powders exhibited the band-edge emission of GaN at 363 nm. GaN nanowires were obtained by nitridation of as-ground $\gamma$ -Ga$_2$S$_3$ powders to GaN powders, followed by sublimation without using templates or catalysts.

• Journal of the Korean Chemical Society
• /
• v.30 no.4
• /
• pp.383-388
• /
• 1986

Kinetics of the reaction of 2-phenylethylarenesulfonates with pyridine in acetonitrile were investigated by an electric conductivity method under 1 to 2,000 bars and at 40∼60${\circ}C$. The rates of these reactions were increased with raising temperatures and pressures, but less than those of the reactions of benzyl benzenesulfonate with pyridine in acetoneitrile were investigated by an electric conductivity method under 1 to 2,000 bars and at 40~60${\circ}C$ .The rates of these reactions were increased with raising temperatures and pressures, but less than those of the reaction of benzyl benzenesulfonate with pyridine in acetone. The activation volumes and activation entropies of 2-phenylethyl m-nosylate were more negatively large than those of benzyl benzenesulfonate. From these phenomena it can be deduced that 2-phenylethyl system has more firmly $S_N2$ character in tranistion state. The Hammett reaction constants are also estimated from the second-order reaction constants. With increasing pressures the reaction parameters $({\rho})$ were decreased, but the $S_N2$ characters were increased. From these results, the reaction mechanism can be adequately described as typical $S_N2$ process under high pressure.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 1998.12a
• /
• pp.527-536
• /
• 1998

블록암호의 설계에서 S-box는 가장 중요한 요소이다. S-box의 크기는 기존공격에 대한 안전도와 수행 시 필요한 메모리량, 수행속도가 동시에 고려되어 선택되어야 한다. 일반적으로 S-box의 입출력의 크기가 커지면 안전도와 메모리 소요량은 크게 증가하며 수행속도는 저하된다. 한편, GF(2$^{n}$ )에서의 멱함수(power permutation)는 DC, LC에 강하므로 여러 암호에 적용되었으나 최근 고계차분공격(higher order differential attack)과 보간공격 (interpolation attack)에 의해 공격된 바 있다. 본문에서는 DC, LC, 고계차분공격, 보간공격에 안전한 S-box로서 GF(2$^{n}$ )에서의 멱함수인 $\chi$$^{-2}$ $^{k}$ (k < n)를 구성하고, n이 짝수일 때 메모리 소요량이 보다 적은 구현방법으로서 GF(2$^{n}$ 2/)의 연산을 이용하는 방법을 제시한다.

• Kyungpook Mathematical Journal
• /
• v.46 no.2
• /
• pp.255-260
• /
• 2006

Let $m$ and $k$ be any positive integers, let $\mathbb{Z}_k$ the ring of integers of modulo $k$, let $G_m(\mathbb{Z}_k)$ the group of all $m$ by $m$ nonsingular matrices over $\mathbb{Z}_k$ and let ${\phi}_m(k)$ the order of $G_m(\mathbb{Z}_k)$. In this paper, ${\phi}_m(k)$ can be computed by the following investigation: First, for any relatively prime positive integers $s$ and $t$, $G_m(\mathbb{Z}_{st})$ is isomorphic to $G_m(\mathbb{Z}_s){\times}G_m(\mathbb{Z}_t)$. Secondly, for any positive integer $n$ and any prime $p$, ${\phi}_m(p^n)=p^{m^2}{\cdot}{\phi}_m(p^{n-1})=p{^{2m}}^2{\cdot}{\phi}_m(p^{n-2})={\cdots}=p^{{(n-1)m}^2}{\cdot}{\phi}_m(p)$, and so ${\phi}_m(k)={\phi}_m(p_1^n1){\cdot}{\phi}_m(p_2^{n2}){\cdots}{\phi}_m(p_s^{ns})$ for the prime factorization of $k$, $k=p_1^{n1}{\cdot}p_2^{n2}{\cdots}p_s^{ns}$.

• Bulletin of the Korean Chemical Society
• /
• v.5 no.6
• /
• pp.226-230
• /
• 1984

LIS's of cis and trans-methyl-2-phenylcyclopropanecarboxylate, cis and trans-t-butyl-2-phenylcyclopropanecarboxylate, cis and trans-N,N-dimethylcyclopropanecarboxamide, trans-2-phenylcyclopropyl methyl ketone and trans-2-phenylcyclopropyl t-butyl ketone have been studied. The LIS's hold the McConnell-Robertson relation and are mainly influenced by the steric effect. LIS's of trans isomers are larger than those of cis isomers. In trans isomers, the LIS's decrease in the following order: methyl ketone > methyl ester > N,N-dimethyl amide > t-butyl ketone${\sim}$t-butyl ester.

• Journal of the Korean Chemical Society
• /
• v.34 no.3
• /
• pp.260-266
• /
• 1990

The electrochemical behavior of N-methyl-2-amino-l-cyclopentene-l-dithiocarboxylic acid $(N-CH_3 acdc) and 2-amino-l-cyclopentene-l-dithiomethyl ester (S-CH_3 acdc) in DMF have been investigated by the use of polarography, cyclic voltammetry and coulometry. The dimer of N-CH_3 acdc is further oxidized at +0.98 V via 2-electron process to produce free sulfur atom and cyclization product. The ring formation between two dithio group occurs along with the elimination of one sulfur atom. The elimination of sulfur atom occurs via two electron oxidation process at + 0.98 V vs. Ag/AgCl electrode. However, the cyclization does not occur in the S-CH_3$ acdc.

• Journal of the Korean Chemical Society
• /
• v.25 no.4
• /
• pp.219-227
• /
• 1981

The crystal structure of sulfamethoxypyridazine has been solved by the direct method and refined by least squares methods from three-dimensional data collected by the multiple-film technique to a final residual of 8.5%. Two molecules (A and B) in one asymmetric unit are different each other in the conformation about S-N(2) bond, and are linked together by N(2A)H${\ldots}$N(3B) and N(2B)H${\ldots}$O(1A)S hydrogen bonds. Benzene and pyridazine rings make the angles of $89^{\circ}$ and $77^{\circ}$ for molecules A and B respectively.

• Composites Research
• /
• v.26 no.3
• /
• pp.189-194
• /
• 2013

This paper deals with the study of mechanical properties and impact energy absorbed by composites, made by using thermoplastic and thermoset as matrix, flax fiber and nanoclay as reinforcements. The nanoclay was sprayed on the fiber laminate directly after mixing with ethanol. This experiment designed by Taguchi method and have variable factors, i.e three types of fiber direction(F), three different nanoclay wt%(N) and three spray gun hole shapes(S). According to these conditions, composites were made and the optimum conditions were found to be F1N3S1, F1N2S1, F1N2S1 and F3N2S1 for thermoplastic, and F1N3S2, F1N3S2, F1N2S2 and F3N2S1 for thermoset which were matched with tensile strength, modulus, total impact absorbed energy and heat release rate respectively.

• Journal for History of Mathematics
• /
• v.21 no.4
• /
• pp.87-104
• /
• 2008

In this paper we investigate several properties and characteristics of the generalized Fibonacci sequence $\{g_n\}$={a, b, a+b, a+2b, 2a+3b, 3a+5b,...}. This concept is a generalization of the famous Fibonacci sequence. In particular we find the identities of sums and the nth term $g_n$ in detail. Also we find the generalizations of the Catalan's identity and A. Tagiuri's identity about the Fibonacci sequence, and investigate the relation between $g_n$ and Pascal's triangle, and how fast $g_n$ increases. Furthermore, we show that $g_n$ and $g_{n+1}$ are relatively prime if a b are relatively prime, and that the sequence $\{\frac{g_{n+1}}{g_n}\}$ of the ratios of consecutive terms converges to the golden ratio $\frac{1+\sqrt5}2$.