• Korean Journal of Mathematics
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• 제18권3호
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• pp.311-322
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• 2010

In this paper, we prove stabilities of the reciprocal difference functional equation $$r(\frac{x+y+z}{3})-r(x+y+z)=\frac{2r(x)r(y)r(z)}{r(x)r(y)+r(y)r(z)+r(z)r(x)}$$ and the reciprocal adjoint functional equation $$r(\frac{x+y+z}{3})+r(x+y+z)=\frac{4r(x)r(y)r(z)}{r(x)r(y)+r(y)r(z)+r(z)r(x)}$$ with three variables. Stabilities of the reciprocal difference functional equation and the reciprocal adjoint functional equation in two variables was proved by K. Ravi, J. M. Rassias and B. V. Senthil Kumar. We extend their results to three variables in similar types.

• 수산해양교육연구
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• 제29권3호
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• pp.785-798
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• 2017

This study was conducted to evaluated the surface(10 variables) and bottom(10 variables) water quality, and sediment(3 variables) in the cage fish farm off Baegyado in Gamak Bay using a multivariate analysis from January 2013 to November 2014. Generally, the environmental data did not show a certain tendency by months during two years investigated. The pairwise simple correlation matrices among variables were also shown. The first four principal components of the surface water in 2013 explain 93% of the total sample variance; the first principal component($z_1$) showed the freshwater inflow and/or precipitation, $z_2$, $z_3$ and $z_4$ related to freshwater inflow and/or precipitation, organic matters and eutrophy, respectively; the first four principal components of the bottom water in 2013 explain 93% of the total sample variance; the $z_1$, $z_2$ and $z_4$ related to freshwater inflow and/or precipitation, and $z_3$ water temperature. In 2014, at the surface water the first three principal components explain 87%; the $z_1$, $z_2$ and $z_3$ related to water temperature, eutrophy and freshwater inflow and/or precipitation, respectively; at the bottom water the first three principal components explain 93%; $z_1$, $z_2$ and $z_3$ related to water temperature, freshwater inflow and/or precipitation and eutrophy. Half of the principal components related to freshwater inflow and/or precipitation.

• 한국약용작물학회지
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• 제11권1호
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• pp.40-45
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• 2003

산초나무는 잎에서 총 52개, 열매에서 48개 향기 성분이 동정되었으며, 4개 지역에서 잎의 주요 공통 성분은 (E)-2-hexenal, ${\alpha}-pinene$, (Z)-ocimene+limonene, estragole, germacrene-d 이였으며, 열매에서는 estragole이였다. Hexanal, (Z)-3-hexenol, (E)-2-hexenal, n-hexanol 성분은 잎에서만 검출되었고, undecanone 성분은 열매에서만 나타났다. 지역간 큰 차이를 보인 잎의 정유성분은 hexanal, azulene이었고, 열매에서는 (Z)-ocimene+limonene이였다. 초피나무 잎에서 총 30개, 열매에서 27개 향기 성분이 동정되었으며, 잎의 주요 공통 성분은 백양사와 내장사지역의 성분이 ${\alpha}-pinene,\;{\beta}-phellandrene$, 1,8-cineole, citronellal이였고, 통도사 지역은 (Z)-3-hexenol, (E)-2-hexenal, ${\alpha}-pinene$, myrcene이 주요성분 이였다. 백양사와 내장사에서 채취한 열매의 공통 성분은 myrcene, (Z)-ocimene+limonene, ${\beta}-phellandrene$이였고, 통도사에서는 ${\beta}-phellandrene$, citronellal, geranyl acetate이 주성분이였다.

• 한국음향학회지
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• 제7권2호
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• pp.65-73
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• 1988

본 논문에서는 음향현미경의 V(z)곡선을 해석하고 실험결과와 비교 고찰하였으며 V(z)곡선과 재료의 탄성 특성사이의 관계를 연구분석하였다. V(z)곡선의 이론적인 해석은 angular spectrum과 ray optics 이론을 사용하였고 실험은 동작주파수가 3MHz인 음향현미경을 구성하여 행하였다. 실험결과 V(z)곡선은 재료마다 고유의 형태를 나타내며 V(z) 곡선에서 극대치 사이의 간격은 재료에서 Rayleigh 파의 음향속도를 산출하는 데 이용될 수 있음을 보였다.

• 한국약용작물학회지
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• 제19권1호
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• pp.1-8
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• 2011

Biological characteristics of 5 Zanthoxylum schinifolium (Zs) fruits such as Z1 (early August), Z2 (middle August), Z3 (middle September), Z4 (early October) and Z5 (middle October) according to harvesting time were evaluated. As fruits ripened, average weight of Zs increased from 4.8mg (Z1) to 50.7mg (Z5), while moisture contents decreased from 74.6% (Z1) to 55.2% (Z5). Crude fat contents of the fruits during ripening increased from 1% (Z1) to 10.6% (Z5). The major fatty acids in Zs were palmitic (C16:0), palmitoleic (C16:1), oleic (C18:1), and linoleic (C18:2) acids. Linoleic acid (C18:2) was a main fatty acid in Z1 and Z2, whereas oleic acid (C18:1) was found as a main one in the other Zs. The ratio of unsaturated fatty acid to total fatty acids increased from 60% (Z1) to 80% (Z3~Z5) during ripening. Among ripening stages, Z4 had the highest contents of total fatty acids ($3,355{\mu}g/g$) and total unsaturated fatty acids ($2,753{\mu}g/g$). Forty six volatile compounds in Zs were also identified. The major volatile compounds were ${\alpha}-pinene$, ${\beta}-myrcene$, ${\beta}-ocimene$, 2-nonanone, estragole, 2-undecanone, and ${\beta}-caryophyllene$. Major volatile components of Z1 were ${\beta}-ocimene$ (20.8 peak area %) and ${\alpha}-pinene$ (9.7 peak area %). In Z2, estragole (30.1 peak area %) was a main volatile compound, but the contents of ${\alpha}-pinene$ (0.4 peak area %), ${\beta}-myrcene$ (0.3 peak area %), and ${\beta}-ocimene$ (0.6 peak area %) were lower than those in Z1. Especially, estragole used as perfumes and as a food additive for flavor was drastically increased to 91.2 (Z3) and 92% (Z4) as fruits ripened.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제11권3호
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• pp.207-215
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• 2004

Let W(z) be a power series with operator coefficients such that multiplication by W(z) is contractive in extC(z). The overlapping space $\varepsilon$(W) of D(W) in C(z) is a Herglotz space with Herglotz function $\varphi$(z) which satisfies $\varphi$(z) + ${\varphi}^*(z^{-1})$ = 2[1-W$^*(z^{-1})W(z)]$.

• 대한수학회보
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• 제39권2호
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• pp.199-209
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• 2002

In this paper, we investigate the problem of stability of the quadratic functional equation f(x+y+z)+f(y-z)+f(y-z)+f(x-z) = 3f(x)+3f(y)+3f(z) on abelian group.

• Korean Journal of Mathematics
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• 제29권3호
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• pp.631-638
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• 2021

In this paper, some sharp inequalities for ordinary derivative P'(z) and polar derivative D_αP(z) = nP(z) + (α - z)P'(z) are obtained by including some of the coefficients and modulus of each individual zero of a polynomial P(z) of degree n not vanishing in the region |z| > k, k ≥ 1. Our results also improve the bounds of Turán's and Aziz's inequalities.

• 한국응용곤충학회지
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• 제53권1호
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• pp.7-13
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• 2014

본 연구에서는 목화진딧물(Aphis gossypii)을 접종한 착색단고추(Capsicum annuum L.)에서 방출된 휘발성물질 및 칠성풀잠자리(Chrysopa cognata) 암컷이 분비한 휘발성물질에 대한 칠성풀잠자리 수컷의 반응이 조사되었다. Y-tube olfactometer에서 칠성풀잠자리 수컷 성충은 목화진딧물이 감염되어 있는 착색단고추에 더 많이 이끌렸고, 수 개의 뚜렷한 GC-EAD 반응을 보였다. 이들 GC-EAD 반응을 보인 피크에 대해 GC-MS 및 GC coupled NMR spectroscopy로 분석한 결과, 목화진딧물이 감염된 착색단고추로부터 4-ethylacetophenone, 3-ethylbenzaldehyde, 3-ethylacetophenone 및 4-ethylbenzaldehyde 그리고 칠성풀잠자리 암컷 성충으로부터 (Z,Z)-4,7-tridecadiene, (Z)-4-tridecene 및 (Z)-4-undecene 등이 동정되었다. 야외 포장시험에서 이들 물질 단독으로는 칠성풀잠자리에 대해 유인효과가 없었다. 암컷 성충에서 기원한 (Z)-4-tridecene와 (Z)-4-undecene은 칠성풀잠자리를 유인하지 못하였고, (Z,Z)-4,7-tridecadiene은 nepetalactol의 유인성을 감소시켰다. 하지만 3-ethylbenzaldehyde와 4-ethylacetophenone는 nepetalactol과 함께 혼합하면 칠성풀잠자리에 대한 유인성은 현저하게 증가하였다.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제11권1호
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• pp.41-56
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• 2007

A 3-partite 2-digraph is an orientation of a 3-partite multi-graph that is without loops and contains at most two edges between any pair of vertices from distinct parts. Let D(X, Y, Z) be a 3-partite 2-digraph with ${\mid}X{\mid}=l,\;{\mid}Y{\mid}=m,\;{\mid}Z{\mid}=n$. For any vertex v in D(X, Y, Z), let $d^+_{\nu}\;and\;d^-_{\nu}$ denote the outdegree and indegree respectively of v. Define $p_x=2(m+n)+d^+_x-d^-_x,\;q_y=2(l+n)+d^+_y-d^-_y\;and\;r_z=2(l+m)+d^+_z-d^-_z$ as the marks (or 2-scores) of x in X, y in Y and z in Z respectively. In this paper, we characterize the marks of 3-partite 2-digraphs and give a constructive and existence criterion for sequences of non-negative integers in non-decreasing order to be the mark sequences of some 3-partite 2-digraph.