• Title/Summary/Keyword: $R^2$

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Platinum(Ⅱ) Complexes of 2,2$^\prime$-Diaminobinaphthyl

  • Jun Moo-Jin;Choi Sung Rack
    • Bulletin of the Korean Chemical Society
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    • v.6 no.4
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    • pp.214-217
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    • 1985
  • Platinum(II) complexes of R-2,2'-diaminobinaphthyl (R-dabn), [Pt(R-dabn)(H2O)2]Cl2, [Pt(R-dabn)(R-Pn)]Cl2, [Pt(R-dabn)(R-bn)]Cl2, and platinum(II) complexes of S-2,2'-diaminobinaphthyl (S-dabn), [Pt(S-dabn)(H2O)2]Cl2, [Pt(S-dabn)(S-Pn)]Cl2, and [(Pt(S-dabn)(S-bn)]Cl2 have been prepared. (R-Pn and S-Pn are, respectively R- and S isomer of 2,3-diaminobutane). R-Pn and S-bn are, respectively R and S isomer of 2,3-diaminopropane). In the vicinity of the B-absorption band region of dabn, the circular dichroism spectra of platinum(Ⅱ) complexes of R-dabn series show a positive B-band followed by a negative higher energy A-band, which is generally understood as the splitting pattern for a ${\lambda}$ conformation, while the circular dichroism spectra of platinum(Ⅱ) complexes of S-dabn series show a negative B-band followed by a positive higher energy A-band in the long-axis polarized absorption region as expected for a $\delta$ conformation.

A Roentgenographic Study on the Development of Human Permanent Posterior Teeth (영구 구치 발육에 관한 방사선학적 연구)

  • Young-Ku Kim
    • Journal of Oral Medicine and Pain
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    • v.16 no.1
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    • pp.73-84
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    • 1991
  • 저자는 연령을 추정하기 위한 기본자료를 얻기 위하여 상하악의 대구치, 소구치의 발육정도를 평가하였다. Orthopantomograph를 촬영한 722명의 3,464개 치아를 대상으로 crown-root ratio를 측정하여 발육정도를 평가하였으며, 다음과 같은 결론을 얻었다. 1. 완전히 형성된 치아의 crown-root ration에는 남녀간에 유의한 차이가 없었다. 2. 발육중인 치아의 crown-root ratio에는 좌우측간에 유의한 차이가 없었다. 3. 각 치아의 crown-root ratio를 이용한 연령추정의 회귀방정식은 다음과 같다. 남자: 여자 : 하악좌측 제 2대구치 : Y=4.599X+7.832(r=0.8337) 하악 좌측 제 2대구치 : Y=4.857X+7.429(r=0.8975) 제 1대구치 : Y=5.179X+2.324(r=0.7948) 제 1대구치 : Y=5.919X+2.018(r=0.8144) 제 2소구치 : Y=3.863X+7.432(r=0.8638) 제 2소구치 : Y=3.679X+7.275(r=0.8819) 제 1소구치 : Y=3.472X+7.120(r=0.8352) 제 1소구치 : Y=4.001X+6.544(r=0.9024) 하악우측 제 2대구치 : Y=4.447X+7.938(r=0.8045) 하악 우측 제 2대구치 : Y=4.653X+7.365(r=0.8598) 제 1대구치 : Y=5.954X+1.495(r=0.7777) 제 1대구치 : Y=5.449X+2.012(r=0.7553) 제 2소구치 : Y=3.894X+7.253(r=0.8689) 제 2소구치 : Y=3.772X+7.025(r=0.8719) 제 1소구치 : Y=4.189X+6.717(r=0.8370) 제 1소구치 : Y=4.327X+6.193(r=0.8524) 상악좌측 제 2대구치 : Y=4.430X+7.722(r=0.7538) 상악 좌측 제 2대구치 : Y=4.876X+7.606(r=0.8311) 제 1대구치 : Y=4.645X+2.886(r=0.6894) 제 1대구치 : Y=6.754X+1.891(r=0.5378) 제 2소구치 : Y=4.391X+6.686(r=0.7700) 제 2소구치 : Y=1.245X+10.575(r=0.1908) 제 1소구치 : Y=5.564X+6.037(r=0.9032) 제 1소구치 : - 상악우측 제 2대구치 : Y=4.587X+7.966(r=0.7882) 상악 우측 제 2대구치 : Y=4.454X+7.803(r=0.8443) 제 1대구치 : Y=4.047X+4.124(r=0.6352) 제 1대구치 : Y=6.336X+2.911(r=0.4688) 제 2소구치 : Y=2.920X+8.089(r=0.7277) 제 2소구치 : Y=3.105X+8.082(r=0.6381) 제 1소구치 : Y=3.264X+6.970(r=0.7292) 제 1소구치 : - 4. Orthopantomograph상의 crown-root ratio를 이용한 연령의 추정에는 상악치아들 보다 하악치아들이 더 정확하게 사용될 수 있다.

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이중 경사 자장 에코와 일반 경사 자장 에코 펄스열로부터의 $\Delta{R}_1$$\Delta{R}_2$에 대한 컴퓨터 가상 실험

  • 김대홍;김은주;서진석
    • Proceedings of the KSMRM Conference
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    • 2002.11a
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    • pp.102-102
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    • 2002
  • 목적:$\Delta{R}_1$$\Delta{R}_2\;^{*}$$T_1$, $T_2\;^{*}$로부터 직접 구해야 하지만, 시간 해상도 때문에 각각 $T_1$, $T_2\;^{*}$ 강조영상으로부터 구하는 것이 일반적이다. $T_1$, $T_2\;^{*}$ 강조영상으로부터 얻은 $\Delta{R}_1$$\Delta{R}_2\;^{*}$ 과 이중 경사 자장에코 펄스열로부터 얻은 $\Delta{R}_1$$\Delta{R}_2\;^{*}$ 를 컴퓨터 가상 실험을 통해서 비교한다. 강조 영상의 신호 세기만으로는 정확한 관류 정보를 얻을 수 없음을 보이고자 한다. 대상 및 방법: 알려진 $\Delta{R}_1$$\Delta{R}_2\;^{*}$ 값을 이용하여 강조영상으로부터 구할 수 있는 $\DeltaR_1$$\Delta{R}_2\;^{*}$ 을 농도에 따라서 가상실험으로 구하고, 이 값과 이중 경사 자장 에코 펄스열로부터 구할 수 있는 $\Delta{R}_1$$\Delta{R}_2\;^{*}$를 가상실험으로 구해서 비교한다.

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ON (${\sigma},\;{\tau}$)-DERIVATIONS OF PRIME RINGS

  • Kaya K.;Guven E.;Soyturk M.
    • The Pure and Applied Mathematics
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    • v.13 no.3 s.33
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    • pp.189-195
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    • 2006
  • Let R be a prime ring with characteristics not 2 and ${\sigma},\;{\tau},\;{\alpha},\;{\beta}$ be auto-morphisms of R. Suppose that $d_1$ is a (${\sigma},\;{\tau}$)-derivation and $d_2$ is a (${\alpha},\;{\beta}$)-derivation on R such that $d_{2}{\alpha}\;=\;{\alpha}d_2,\;d_2{\beta}\;=\;{\beta}d_2$. In this note it is shown that; (1) If $d_1d_2$(R) = 0 then $d_1$ = 0 or $d_2$ = 0. (2) If [$d_1(R),d_2(R)$] = 0 then R is commutative. (3) If($d_1(R),d_2(R)$) = 0 then R is commutative. (4) If $[d_1(R),d_2(R)]_{\sigma,\tau}$ = 0 then R is commutative.

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Identification and Pathogenicity of Rhizoctonia species Isolated from Turfgrasses (잔디에서 분리한 Rhizoctonia spp.의 동정과 병원성)

  • Lee, Du-Hyung;Choe, Yang-Yun;Lee, Jae-Hong;Kim, Jin-Won
    • The Korean Journal of Mycology
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    • v.23 no.3 s.74
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    • pp.257-265
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    • 1995
  • Morphological characteristics and pathogenicity of Rhizoctonia species causing blight diseases of turfgrasses were studied. The species were identified as Rhizoctonia cerealis Van der Hoeven, R. oryzae Ryker et Gooch, and R. solani $K{\ddot{u}hn}$ based on their morphological and cultural characteristics. Isolates of R. solani were assigned to anastomosis groups (AG) with cultural type 1 (1A), 2-2 (IIIB), and 2-2 (IV). R. cerealis, R. oryzae and R. solani induced sheath rot and foliar blight symptoms on creeping bentgrass (Agrostis palustris) and zoysiagrass (Zoysia japonica). Inoculation tests showed that disease severity with isolates of R. cerealis and R. oryzae were more serious to creeping bentgrass than zoysiagrass. AG 1(1A) isolates of R. solani were strongly pathogenic on creeping bentgrass, but moderate to zoysiagrass. AG 2-2 (III) isolates were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass. AG 2-2 (IV) isolates from zoysiagrass were moderately pathogenic to zoysiagrass, but weakly to creeping bentgrass.

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A Stereospecific Synthesis of (+)-2-Epideoxymannojirimycin and (2R,3R,4R,5R)-3,4,5-Trihydroxypipecolic Acid

  • 박기훈
    • Bulletin of the Korean Chemical Society
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    • v.16 no.10
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    • pp.985-988
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    • 1995
  • 2-Epideoxymannojirimycin 1 and (2R,3R,4R,5R)-3,4,5-trihydroxypipecolic acid 2 were prepared starting from D-glucosamic acid as a chiral educt. Key transformations were selective removal of the terminal isopropylidene group and intramolecular cyclization by SN2 reaction.

GENERATING NON-JUMPING NUMBERS OF HYPERGRAPHS

  • Liu, Shaoqiang;Peng, Yuejian
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.4
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    • pp.1027-1039
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    • 2019
  • The concept of jump concerns the distribution of $Tur{\acute{a}}n$ densities. A number ${\alpha}\;{\in}\;[0,1)$ is a jump for r if there exists a constant c > 0 such that if the $Tur{\acute{a}}n$ density of a family $\mathfrak{F}$ of r-uniform graphs is greater than ${\alpha}$, then the $Tur{\acute{a}}n$ density of $\mathfrak{F}$ is at least ${\alpha}+c$. To determine whether a number is a jump or non-jump has been a challenging problem in extremal hypergraph theory. In this paper, we give a way to generate non-jumps for hypergraphs. We show that if ${\alpha}$, ${\beta}$ are non-jumps for $r_1$, $r_2{\geq}2$ respectively, then $\frac{{\alpha}{\beta}(r_1+r_2)!r_1^{r_1}r_2^{r_2}}{r_1!r_2!(r_1+R_2)^{r_1+r_2}}$ is a non-jump for $r_1+r_2$. We also apply the Lagrangian method to determine the $Tur{\acute{a}}n$ density of the extension of the (r - 3)-fold enlargement of a 3-uniform matching.

A NOTE ON WITT RINGS OF 2-FOLD FULL RINGS

  • Cho, In-Ho;Kim, Jae-Gyeom
    • Bulletin of the Korean Mathematical Society
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    • v.22 no.2
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    • pp.121-126
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    • 1985
  • D.K. Harrison [5] has shown that if R and S are fields of characteristic different from 2, then two Witt rings W(R) and W(S) are isomorphic if and only if W(R)/I(R)$^{3}$ and W(S)/I(S)$^{3}$ are isomorphic where I(R) and I(S) denote the fundamental ideals of W(R) and W(S) respectively. In [1], J.K. Arason and A. Pfister proved a corresponding result when the characteristics of R and S are 2, and, in [9], K.I. Mandelberg proved the result when R and S are commutative semi-local rings having 2 a unit. In this paper, we prove the result when R and S are 2-fold full rings. Throughout this paper, unless otherwise specified, we assume that R is a commutative ring having 2 a unit. A quadratic space (V, B, .phi.) over R is a finitely generated projective R-module V with a symmetric bilinear mapping B: V*V.rarw.R which is nondegenerate (i.e., the natural mapping V.rarw.Ho $m_{R}$ (V, R) induced by B is an isomorphism), and with a quadratic mapping .phi.:V.rarw.R such that B(x,y)=(.phi.(x+y)-.phi.(x)-.phi.(y))/2 and .phi.(rx)= $r^{2}$.phi.(x) for all x, y in V and r in R. We denote the group of multiplicative units of R by U(R). If (V, B, .phi.) is a free rank n quadratic space over R with an orthogonal basis { $x_{1}$, .., $x_{n}$}, we will write < $a_{1}$,.., $a_{n}$> for (V, B, .phi.) where the $a_{i}$=.phi.( $x_{i}$) are in U(R), and denote the space by the table [ $a_{ij}$ ] where $a_{ij}$ =B( $x_{i}$, $x_{j}$). In the case n=2 and B( $x_{1}$, $x_{2}$)=1/2, we reserve the notation [ $a_{11}$, $a_{22}$] for the space.the space.e.e.e.

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AN EXTREMAL PROBLEM ON POTENTIALLY $K_{r,r}$-ke-GRAPHIC SEQUENCES

  • Chen, Gang;Yin, Jian-Hua
    • Journal of applied mathematics & informatics
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    • v.27 no.1_2
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    • pp.49-58
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    • 2009
  • For $1{\leq}k{\leq}r$, let ${\sigma}$($K_{r,r}$ - ke, n) be the smallest even integer such that every n-term graphic sequence ${\pi}$ = ($d_1$, $d_2$, ..., $d_n$) with term sum ${\sigma}({\pi})$ = $d_1$ + $d_2$ + ${\cdots}$ + $d_n\;{\geq}\;{\sigma}$($K_{r,r}$ - ke, n) has a realization G containing $K_{r,r}$ - ke as a subgraph, where $K_{r,r}$ - ke is the graph obtained from the $r\;{\times}\;r$ complete bipartite graph $K_{r,r}$ by deleting k edges which form a matching. In this paper, we determine ${\sigma}$($K_{r,r}$ - ke, n) for even $r\;({\geq}4)$ and $n{\geq}7r^2+{\frac{1}{2}}r-22$ and for odd r (${\geq}5$) and $n{\geq}7r^2+9r-26$.

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THE STRUCTURE OF SEMIPERFECT RINGS

  • Han, Jun-Cheol
    • Journal of the Korean Mathematical Society
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    • v.45 no.2
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    • pp.425-433
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    • 2008
  • Let R be a ring with identity $1_R$ and let U(R) denote the group of all units of R. A ring R is called locally finite if every finite subset in it generates a finite semi group multiplicatively. In this paper, some results are obtained as follows: (1) for any semilocal (hence semiperfect) ring R, U(R) is a finite (resp. locally finite) group if and only if R is a finite (resp. locally finite) ring; U(R) is a locally finite group if and only if U$(M_n(R))$ is a locally finite group where $M_n(R)$ is the full matrix ring of $n{\times}n$ matrices over R for any positive integer n; in addition, if $2=1_R+1_R$ is a unit in R, then U(R) is an abelian group if and only if R is a commutative ring; (2) for any semiperfect ring R, if E(R), the set of all idempotents in R, is commuting, then $R/J\cong\oplus_{i=1}^mD_i$ where each $D_i$ is a division ring for some positive integer m and |E(R)|=$2^m$; in addition, if 2=$1_R+1_R$ is a unit in R, then every idempotent is central.