• Bulletin of the Korean Mathematical Society
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• v.50 no.5
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• pp.1501-1511
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• 2013

A ring R is called linearly McCoy if whenever linear polynomials $f(x)$, $g(x){\in}R[x]{\backslash}\{0\}$ satisfy $f(x)g(x)=0$, there exist nonzero elements $r,s{\in}R$ such that $f(x)r=sg(x)=0$. In this paper, extension properties of linearly McCoy rings are investigated. We prove that the polynomial ring over a linearly McCoy ring need not be linearly McCoy. It is shown that if there exists the classical right quotient ring Q of a ring R, then R is right linearly McCoy if and only if so is Q. Other basic extensions are also considered.

• Journal of the Korean Chemical Society
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• v.53 no.5
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• pp.530-535
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• 2009

Dicyclohexyl telluride was obtained in a high yield by the reaction of cyclohexyl bromide with NaTeH(prepared in situ) in an aqueous ethanolic solution. A series of new organotelluronium salts of the general formula ${(cyclo-C_6H_11)}_2Te(R)X$ (where R = $CH_3$, X = I (1); R = $C_2H_5$, X = Br(2); R = $C_2H_5$, X = I (3); R = C_3H_5$, X = Br (4)) were prepared by the reaction of ${(cyclo-C_6H_11)}_2Te$ with the corresponding alkyl halide. Reaction of 1 with NaBPh4 gave compound 5 ( i.e. R = CH3, X = BPh4 ‒) in 78% yield. Reaction of ${(cyclo-C_6H_11)}_2Te$ with benzyl bromide and 4-bromophenacyl bromide gave unexpectedly dibenzylcyclohexyltelluronium bromide (6) and bis(4-bromophenacyl)cyclohexyltelluronium bromide (7), respectively. Reaction of 6 with NaBPh4 gave the corresponding tetraphenylborate derivative (8) in high yield. $^1H$ NMR studies revealed that in $CDCl_3$solution compound 1 eliminated alkyl halide. Conductivity, IR, $^1H\;and\;^{13}C$ NMR and thermal data for the new compounds are presented and discussed.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.777-782
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• 2010

This research tested five modified Hoagland solutions for proper fertility management of nitrogen in 'Seolhyang' strawberry cultivations. The changes of nutrient solutions were in total nitrogen concentrations ($meq{\cdot}L^{-1}$) such as 0 (${NO^-}_3$), 2.5 (${NO_3}^-$), 5 (${NO_3}^-$), 10 ($7.5{NO_3}^-$ + $2.5{NH_4}^+$) and 15 ($10{NO_3}^-$ + $5{NH_4}^+$). The fresh weight and $NO_3$-N concentrations in petiole sap responded to the elevated nitrogen concentrations in fertilizer solution in quadratic (y=7.10+2.668x-$0.115x^2$, $R^2=0.7983^{***}$) and linear (y=26.14+5.245x, $R^2=0.6083^{***}$), respectively. The dry weight and N content of the above ground plant tissue responded to the elevated nitrogen in quadratic (y=2.140+0.492x-$0.022x^2$, $R^2=0.6110^{***}$) and linear (y=0.569+0.033x, $R^2=0.6952^{***}$), respectively. In our experiment the solution with $5meq{\cdot}L^{-1}$ of ${NO_3}^-$ showed positive results in both dry and fresh weight productions. However, a future research about modification of this solution and growth and nutrient uptake response is necessary to achieve better growth of 'Seolhyang' strawberry.

• Journal of the Korean Chemical Society
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• v.36 no.3
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• pp.460-465
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• 1992

The structure of th 5S rRNA isolated from Xanthomonas citri was determined by enzymatic and chemical degradation methods. It consists of 119 nucleotides and contains no modified nucleosides. As does the 5S rRNA of X. maltophilia, it contains an additional uridine residue on the 5'-terminus. The secondary structure of the 5S rRNA from X. citri was almost identical to the generalized models proposed by many other workers [De Wachter et al., Biochimie, 64, 311 (1982); Specht et al., Nucleic Acids Res., 18, 2215 (1990); Cho et al., Proceedings of the First Symposium on Biomolecules, p. 9 (1991)]. The secondary structure of 5S rRNA from X. citri consists of five helices, five loops and two bulges. This 5S rRNA has a uridine residue at position 66 as a bulge.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1234-1239
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• 1999

Electromagnetic wave asorbing properties of the $Ni_{0.5}-Zn_{0.4}-X_{0.1}{\cdot}Fe_2O_4$, where X was replaced by substitution elements Cu, Mg, Mn, have been studied. The structure, shape, size and magnetic properties of the $Ni_{0.5}-Zn_{0.4}-X_{0.1}{\cdot}Fe_2O_4$ were analyzed by XRD, SEM, VSM. The relative complex permittivity, permeability, and electromagnetic wave absorbing properties were measured by Network Analyzer. The structure, shape, size and magnetization value of the $Ni_{0.5}-Zn_{0.4}-X_{0.1}{\cdot}Fe_2O_4$ were found to be similar in spite of substitution elements. The coercive force and hysteresis-loss showed maximum value when Mg was substituted for X. The dielectric loss(${\varepsilon}_r"/{\varepsilon}_r'$) was found to be maximum value when Mn was substituted for X. Also the magnetic loss(${\mu}_r"/{\mu}_r'$} was found to be maximum with Cu substitution. The electromagnetica wave absorbing property of the $Ni_{0.5}-Zn_{0.4}-X_{0.1}{\cdot}Fe_2O_4$-Rubber composite with 4mm thickness was excellent as over - 40dB at 9GHz, and the $Ni_{0.5}-Zn_{0.4}-X_{0.1}{\cdot}Fe_2O_4$-Rubber composite with 8mm thickness was over-40dB at 2GHz. Those composites also showed superior microwave absorbing properties.

• Bulletin of the Korean Mathematical Society
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• v.47 no.5
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• pp.907-913
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• 2010

Let D be an integrally closed domain with quotient field K, * be a star operation on D, X, Y be indeterminates over D, $N_*\;=\;\{f\;{\in}\;D[X]|\;(c_D(f))^*\;=\;D\}$ and $R\;=\;D[X]_{N_*}$. Let b be the b-operation on R, and let $*_c$ be the star operation on D defined by $I^{*_c}\;=\;(ID[X]_{N_*})^b\;{\cap}\;K$. Finally, let Kr(R, b) (resp., Kr(D, $*_c$)) be the Kronecker function ring of R (resp., D) with respect to Y (resp., X, Y). In this paper, we show that Kr(R, b) $\subseteq$ Kr(D, $*_c$) and Kr(R, b) is a kfr with respect to K(Y) and X in the notion of [2]. We also prove that Kr(R, b) = Kr(D, $*_c$) if and only if D is a $P{\ast}MD$. As a corollary, we have that if D is not a $P{\ast}MD$, then Kr(R, b) is an example of a kfr with respect to K(Y) and X but not a Kronecker function ring with respect to K(Y) and X.

• Journal of the Korean Ceramic Society
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• v.45 no.5
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• pp.290-296
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• 2008

$AB'_{0.5}B"_{0.5}O_3$ type complex perovskite structures which have been reported as proton conductors over $600^{\circ}C$ were studied. The $AB'_{0.5}B"_{0.5}O_3$ type complex perovskite structure is known to be more easily synthesized and has better stability than normal $ABO_3$ perovskite structure. And it is stable at about $800^{\circ}C$ in the $CO_2$ atmosphere, whereas the $BaCeO_3$ perovskite is easily decomposed into carbonate. In addition, this $AB'_{0.5}B"_{0.5}O_3$ type complex perovskite structure could simply produce oxygen vacancies within their structure not by introducing additional doping oxides but by just controling the molar ratio of $B'^{+3}$ and $B"^{+5}$ metal ions in the B site. Hence it is easy to design the structure which shows highly sensitive electrical conductivity to humidity. In this study, the single phase boundary of $BaR_{0.5+x}Ta_{0.5-x}O_{3-{\delta}}$(R = rare earth) complex perovskite structures and it's phase stability were investigated with changes in composition, x. And the humidity dependance of electrical conductivity at different $P_{H2O}$ conditions was investigated.

• Bulletin of the Korean Mathematical Society
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• v.50 no.5
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• pp.1433-1439
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• 2013

A ring R is called left morphic if $$R/Ra{\simeq_-}l(a)$$ for every $a{\in}R$. Equivalently, for every $a{\in}R$ there exists $b{\in}R$ such that $Ra=l(b)$ and $l(a)=Rb$. A ring R is called left quasi-morphic if there exist $b$ and $c$ in R such that $Ra=l(b)$ and $l(a)=Rc$ for every $a{\in}R$. A result of T.-K. Lee and Y. Zhou says that R is unit regular if and only if $$R[x]/(x^2){\simeq_-}R{\propto}R$$ is morphic. Motivated by this result, we investigate the morphic property of the ring $$S_n=^{def}R[x_1,x_2,{\cdots},x_n]/(\{x_ix_j\})$$, where $i,j{\in}\{1,2,{\cdots},n\}$. The morphic elements of $S_n$ are completely determined when R is strongly regular.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.215-222
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• 1999

Platycodon root contains abundant pharmaceutical substances and is widely used as a food and a medicinal herb. This study was conducted to determine the cultural environment and soil morphological characteristics of platycodon. Sampling sites were Keochang 4, Kimhae 7, Haman 6, Chinju 6 and Koseong 3 fields in Kyongnam province and Hongcheong 6 fields in Kangwon province. The average continious cropping year was highest Chinju 8.0-years old, whereas lowest Hongcheon 2.3-years old. The average cropping area and compost application were highest Hongcheon 1.3ha and $108Mg\;ha^{-1}$ respectively than other areas. The slope was in order to Koseong steep slope with 35%. Koechang 28%, Flaman 16%, Chinju 11.7%, Kimhae 11% and Hongcheon 7.5%. The drainage classes was well drained in Koechang. Kimhae, Chinju and Koseong, while it s poorly drained in Hongcheon and Haman. Distribution of topography was highest rolling 37.9% and drainage classes was highest well drained 48.3%. The root disease incidence rate was in the order of Haman 56.8%, Hongcheon 52.5%, Kimhae 36.7%, Koechang 35.3%, Chinju 32.3% and Koseong 30.0%. The yield at the Chinju $36.17Mg\;ha^{-1}$ was higher than that of Koseong $25.00Mg\;ha^{-1}$, Kimhae $13.57Mg\;ha^{-1}$, Koechang $11.75Mg\;ha^{-1}$, Haman $9.50Mg\;ha^{-1}$ and Hongcheon $5.24Mg\;ha^{-1}$. The average temperature was correlated with the disease incidence rate by $Y=3.07X^2-87.16X+649.26(R^2=0.947^{**})$ and yield by $Y=-478.68X^2+13403X-90836(R^2=0.763^*)$. The root disease incidence rate was correlated with drainage classes Y=19.1X-5.26($R^2=0.592{***}$), topography Y=9.68X+10.77($R^2=0.205^{**}$) and slope Y=0.85X+-27.88 ($R^2=0.143^*$). The yield was correlated with drainage classes Y=-10X+42($R^2=0.348^{**}$), topography Y=-5.34X+34.5 ($R^2=0.134^*$) and slope Y=-0.68X+25.48($R^2=0.129^*$). The optimum cultivated land of perennial platycodon was average temperature $14^{\circ}C$, direction of southeast, topography of flat or undulating, slope of 0-6%, well drained.

• Journal of applied mathematics & informatics
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• v.39 no.5_6
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• pp.617-622
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• 2021

Let R be a commutative ring with identity, R[X] the polynomial ring over R and S a multiplicative subset of R. Let U = {f ∈ R[X] | f is monic} and let N = {f ∈ R[X] | c(f) = R}. In this paper, we show that if S is an anti-Archimedean subset of R, then R is an S-Noetherian ring if and only if R[X]_U is an S-Noetherian ring, if and only if R[X]_N is an S-Noetherian ring. We also prove that if R is an integral domain and R[X]_U is an S-principal ideal domain, then R is an S-principal ideal domain.