• Honam Mathematical Journal
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• v.28 no.3
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• pp.395-398
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• 2006

In this note, for any given positive integer n, we determine all the continuous solutions f : R ${\rightarrow}$ R of the integral-functional equation $f^n(x)=n_{_o}{^x}f(t)dt$.

• The Korean Journal of Mycology
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• v.27 no.5 s.92
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• pp.337-340
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• 1999

The context and upper surface of Phellinus basidiocarp become blackened, rimose and woody. The basidiocarp is sessile, dimidiate and elongate. The basidiospores are pigmented and ovoid to globose. Hymenial setae are $17{\sim}35{\times}6{\sim}8{\mu}m$. Nineteen isolates of Phellinus species, including Phellinus linteus, were used for sequencing of the internal transcribed spacer (ITS) region of the nuclear rDNA. Based on these sequence data, specific primers were designed for identification of Phellinus linteus isolates in Korea. The specific primers were within the ITS1 and ITS2 regions and were nested within the universal primers flanking the spacer regions. A total of four primers (the universal primers ITS-1F and ITS-4, and the specific primers PL-F and PL-R) were used for detection of Phellinus linteus collected in Korea. The length of the four amplification products of Phellinus linteus DNA were 800 bp (ITS-1F/ITS-4), two bands of about 720 bp (ITS-1F/PL-R and PL-F/ITS-4), and 610 bp (PL-F/PL-R). Among 23 isolates of Phellinus species collected in Korea, Thirteen isolates were identified as Phellinus linteus based on the presence of the four bands. The other species produced only the single ITS-1F/ITS-4 product.

• Bulletin of the Korean Mathematical Society
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• v.48 no.6
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• pp.1253-1259
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• 2011

Let R be a prime ring, I a nonzero ideal of R and n a fixed positive integer. If R admits a generalized derivation F associated with a derivation d such that c for all x, $y{\in}I$. Then either R is commutative or n = 1, d = 0 and F is the identity map on R. Moreover in case R is a semiprime ring and $(F([x,\;y]))^n=[x,\;y]$ for all x, $y{\in}R$, then either R is commutative or n = 1, $d(R){\subseteq}Z(R)$, R contains a non-zero central ideal and for all $x{\in}R$.

• Korean Journal of Mathematics
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• v.8 no.1
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• pp.27-32
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• 2000

In this paper, we show that for any continuous map $f$ of the circle $S^1$ to itself, (1) $x{\in}{\Omega}(f){\backslash}\overline{R(f)}$, then $x$ is not a turning point of $f$ and (2) if $P(f)$ is non-empty, then $R(f)$ is closed if and only if $AP(f)$ is closed.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2004.05a
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• pp.48-56
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• 2004

To perform R&D program, it is necessary to invest input factor(I/F). And these factor are converted to output factors(O/F) at the end of R&D program. Pee. reviewers evaluate output factors and produce evaluation grades(E/G). This paper try to analyze the relationship to I/F, O/F and E/G, According to the analysis results, the relation between I/F and E/G is as weak as the relation between O/F and E/G. The strength of relationship is relatively very strong in the relation between I/F and O/F

• Journal for History of Mathematics
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• v.24 no.2
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• pp.71-89
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• 2011

This article discusses and reviews the mathematics education of F. Klein who had a leading role in the reform movement of mathematics education from the late 19th century. We are mainly investigated the 'Erlanger Antrittsrede' in 1872 that showed Klein's view on early mathematics education and the 'Meraner Lehrplan f$\"{u}$r Mathematik' in 1905 that Widely known, the basis of the curriculum of modern mathematics education. Based on this, We discusses the educational implications-the purpose and methods of mathematics education, teacher education and so on.

• Communications of the Korean Mathematical Society
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• v.9 no.3
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• pp.687-700
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• 1994

Throughout this paper we will let H denote the complete Heyting algebra ($H, \vee, \wedge, *$) with order reversing involution *. 0 and 1 denote the supermum and the infimum of $\emptyset$, respectively. Given any set X, any element of $H^X$ is called H-fuzzy set (or, simply f.set) in X and will be denoted by small Greek letters, such as $\mu, \nu, \rho, \sigma$. $H^X$ inherits a structure of H with order reversing involution in natural way, by definding $\vee, \wedge, *$ pointwise (sam notations of H are usual). If $f$ is a map from a set X to a set Y and $\mu \in H^Y$, then $f^{-1}(\mu)$ is the f.set in X defined by f^{-1}(\mu)(x) = \mu(f(x))$. Also for $\sigma \in H^X, f(\sigma)$ is the f.set in Y defined by $f(\sigma)(y) = sup{\sigma(x) : f(x) = y}$ ([4]). A preorder R on a set X is reflexive and transitive relation on X, the pair (X,R) is called preordered set. A map $f$ from a preordered set (X, R) to another one (Y,T) is said to be preorder preserving (inverting) if for $x,y \in X, xRy$ implies $f(x)T f(y) (resp. f(y)Tf(x))$. For the terminology and notation, we refer to [10, 11, 13] for category theory and [7] for H-fuzzy semitopogenous spaces.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.13
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• pp.329-346
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• 2000

The marine cargo insurance is mainly the insurance on foreign trade commodities. The sales contract stipulates as to which of the seller or the buyer should arrange the insurance. In other words, if the sales contract is made on the C.I.F. terms, the seller has to arrange the insurance, while, in the case of F.O.B. or C.F.R. terms, the buyer has to arrange it. The F.O.B. or C.F.R. terms means that the seller has to take out an insurance for himself until the cargo being loaded onboard the overseas vessel at the port of shipment in export country. But our country has not reasonable insurance to cover seller's risk, because it hasn't yet implemented the insurance. In respect of a cargo exported from Korea on F.O.B. or C.F.R. terms, the F.O.B. insurance covers comprehensively the inland transit and storage until the cargo being loaded onboard the overseas vessel at the port of shipment in Korea with a certain limitation of a insurance period. The goal of this study is to analyze the development propriety of F.O.B. Insurance. This could be done through analyzing the volume and analyzing the proportion of F.O.B. or C.F.R. terms for export. It is supposed that the potential demands of F.O.B. insurance are sufficient in our country for developing the F.O.B. insurance. At this point of time, the positive development of F.O.B. insurance for export is inevitable from the viewpoint of present situation of trading circles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.131-134
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• 2003

[ $ZnWO_4$ ] shows excellent frequency selectivity due to its high quality factor($Q{\times}f$) at microwave frequencies. However, in order to use $ZnWO_4$ as multilayered wireless communication components, its other properties such as sintering temperature($1050^{\circ}C$), ${\tau}_f$ ($-70ppm/^{\circ}C$) and ${\varepsilon}_r(15.5)$ should be modified. In present study, $TiO_2$ and LiF were used to improve the microwave dielectric and sintering properties of $ZnWO_4$. $TiO_2$ additions to $ZnWO_4$ changed ${\tau}_f$ from negative to positive value, and also increased ${\varepsilon}_r$ due to its high ${\tau}_f$ ($+400ppm/^{\circ}C$) and ${\varepsilon}_r$(100). At 20 mol% $TiO_2$ addition, ${\tau}_f$ was controlled to near zero $ppm/^{\circ}C$ with ${\varepsilon}_r=19.4$ and $Q{\times}f=50000GHz$. However, the sintering temperature was still high to $1100^{\circ}C$. LiF addition to the $ZnWO_4+TiO_2$ mixture was greatly reduced the sintering temperature from $1100^{\circ}C$ to $850^{\circ}C$ due to liquid phase formation. Also LiF addition decreased the ${\tau}_f$ value due to its high negative ${\tau}_f$ value. Therefore, by controlling the $TiO_2$ and LiF amount, temperature stable LTCC material in the $ZnWO_4$-TiO_2-LiF$ system could be fabricated.

• Applied Biological Chemistry
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• v.32 no.2
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• pp.170-177
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• 1989

In order to seek the molecular basis of higher insecticidal activity of the carbamates with two methyl groups, m-xylyl-N-methylcarbamate(MXNMC) than the corresponding unsubstituted phenyl N-methylcarbamate(PNMC), these two derivatives have been studied by molecular orbital(MO) theoretically using extended $H\ddot{u}ckel$ theory(EHT), and analysis of regression and linear free energy relationship(LFER). The most stable stereo structure(Z, Z) shows that the phenyl group occupies vertical(${\theta}=90^{\circ}$) position on the plane of the N-methylcarbamyl group. Regression analysis shows that especially good correlation exists between the $pI_{50}$ values and the calculated MO quantities when the hydrogen atomic charge of metaposition and of m-methyl groups, and LUMO energy are taken as variables. The LFER analysis on the carbamylation indicates that field(F) effect(60%) is slightly larger than resonance(R) effect(40%) in PNMC(E>R), whereas, in case of MXNMC, R effect(98.6%) is much larger than F effect(1.4%)($R{\gg}F$). From the basis on the findings, the enhancement of insecticidal activity of MXNMC may be the result of hyperconjugation by m-methyl groups.