• Title/Summary/Keyword: PHI

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Molecular Phylogeny of Korean-type Coliphages and American-type Coliphages Determined by a RAPD Analysis (RAPD 분석법에 의한 한국형 대장균파아지와 미국형 대장균파아지의 분자적 계통분류)

  • 권오식
    • Biomedical Science Letters
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    • v.6 no.2
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    • pp.131-139
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    • 2000
  • RAPD-PCR was applied to identify the phylogenetic relationship between isolated Korean-type coliphages ($\phi$C1, $\phi$C2, $\phi$C3 and $\phi$C4) and well-known American coliphages ($\phi$T2, $\phi$T4, $\phi$T5, $\phi$T7 and ${\phi}{\lambda}$). Subsequently, a computer analysis was carried out with the results of RAPD-PCR. As a result, 9 individuals were divided into five groups. The Korean-type coliphages formed a single cluster which showed very high genetic similarity but the American-type coliphages revealed very low genetic similarity among them. In particular, the $\phi$T2와 $\phi$T4 (T$_{even}$ phages) made one sub-cluster among American coliphages, and they were very distant from $\phi$T5, $\phi$T7 and ${\phi}{\lambda}$. However, ${\phi}{\lambda}$ made a cluster with the Korean-type coliphages that we isolated. The genome size of Korean-type coliphages was ranged from 25,000 bp to 35,000 bp. Among them, the genome of $\phi$C2 was the smallest and that of $\phi$C1 was the biggest, while others were in the middle of the size.

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Basic Study on the Regenerator of Stirling Engine (IV) - Heat Transfer and Flow Friction Characteristic of the Regenerator with Steel Wire Matrix - (스털링 기관용 재생기에 관한 기초 연구 (IV) - 철선을 축열재로 한 재생기의 전열 및 유동손실 특성 -)

  • Oh D. G.;Kim T. H.
    • Journal of Biosystems Engineering
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    • v.30 no.4
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    • pp.202-209
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    • 2005
  • The output of Stirling engine is influenced by the regenerator effectiveness. The regenerator effectiveness is influenced by heat transfer and flow friction loss of the regenerator matrix. In this paper, in order to provide a basic data for the design of regenerator matrix, characteristics of heat transfer and flow friction loss were investigated by a packed method of matrix in the oscillating flow as the same condition of operation in a Stirling engine. As matrices, 6 kinds of steel wires, 4 kinds of combined steel wires, 8 kinds of combined steel wires with screen meshes were used. The results are summarized as follows; Among 6 kinds of steel wires $({\phi}0.7\;mm,\;{\phi}0.9\;mm,\;{\phi}1.2\;mm,\;{\phi}\;1.6\;mm,\;{\phi}2.0\;mm,\;{\phi}2.7\;mm),$ the two steel wires $({\phi}0.7\;mm,\;{\phi}0.9\;mm)$ showed the highest in effectiveness. Among 4 kinds of combined steel wires $({\phi}l.6-{\phi}l.2\;mm,\;{\phi}1.2-{\phi}l.6\;mm,\;{\phi}0.9-{\phi}l.2\;mm,\;{\phi}l.2-{\phi}0.9\;mm),\;the\;{\phi}1.2-{\phi}0.9\;mm$ showed the highest in effectiveness. Among 8 kinds of combined steel wires with screen meshes $(150-{\phi}0.9\;mm,\;150-{\phi}l.2\;mm,\;{\phi}0.9\;mm-150,\;{\phi}1.2\;mm-150,\;150-{\phi}0.9\;mm-150,\;150-{\phi}1.2\;mm-150,\;150-{\phi}l.6\;mm-150,\;150-{\phi}2.0\;mm-150),\;the\;{\phi}l.2\;mm-150$ showed the highest in effectiveness.

SUBGROUP ACTIONS AND SOME APPLICATIONS

  • Han, Juncheol;Park, Sangwon
    • Korean Journal of Mathematics
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    • v.19 no.2
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    • pp.181-189
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    • 2011
  • Let G be a group and X be a nonempty set and H be a subgroup of G. For a given ${\phi}_G\;:\;G{\times}X{\rightarrow}X$, a group action of G on X, we define ${\phi}_H\;:\;H{\times}X{\rightarrow}X$, a subgroup action of H on X, by ${\phi}_H(h,x)={\phi}_G(h,x)$ for all $(h,x){\in}H{\times}X$. In this paper, by considering a subgroup action of H on X, we have some results as follows: (1) If H,K are two normal subgroups of G such that $H{\subseteq}K{\subseteq}G$, then for any $x{\in}X$ ($orb_{{\phi}_G}(x)\;:\;orb_{{\phi}_H}(x)$) = ($orb_{{\phi}_G}(x)\;:\;orb_{{\phi}_K}(x)$) = ($orb_{{\phi}_K}(x)\;:\;orb_{{\phi}_H}(x)$); additionally, in case of $K{\cap}stab_{{\phi}_G}(x)$ = {1}, if ($orb_{{\phi}_G}(x)\;:\;orb_{{\phi}H}(x)$) and ($orb_{{\phi}_K}(x)\;:\;orb_{{\phi}_H}(x)$) are both finite, then ($orb_{{\phi}_G}(x)\;:\;orb_{{\phi}_H}(x)$) is finite; (2) If H is a cyclic subgroup of G and $stab_{{\phi}_H}(x){\neq}$ {1} for some $x{\in}X$, then $orb_{{\phi}_H}(x)$ is finite.

ON ϕ-PSEUDO ALMOST VALUATION RINGS

  • Esmaeelnezhad, Afsaneh;Sahandi, Parviz
    • Bulletin of the Korean Mathematical Society
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    • v.52 no.3
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    • pp.935-946
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    • 2015
  • The purpose of this paper is to introduce a new class of rings that is closely related to the classes of pseudo valuation rings (PVRs) and pseudo-almost valuation domains (PAVDs). A commutative ring R is said to be ${\phi}$-ring if its nilradical Nil(R) is both prime and comparable with each principal ideal. The name is derived from the natural map ${\phi}$ from the total quotient ring T(R) to R localized at Nil(R). A prime ideal P of a ${\phi}$-ring R is said to be a ${\phi}$-pseudo-strongly prime ideal if, whenever $x,y{\in}R_{Nil(R)}$ and $(xy){\phi}(P){\subseteq}{\phi}(P)$, then there exists an integer $m{\geqslant}1$ such that either $x^m{\in}{\phi}(R)$ or $y^m{\phi}(P){\subseteq}{\phi}(P)$. If each prime ideal of R is a ${\phi}$-pseudo strongly prime ideal, then we say that R is a ${\phi}$-pseudo-almost valuation ring (${\phi}$-PAVR). Among the properties of ${\phi}$-PAVRs, we show that a quasilocal ${\phi}$-ring R with regular maximal ideal M is a ${\phi}$-PAVR if and only if V = (M : M) is a ${\phi}$-almost chained ring with maximal ideal $\sqrt{MV}$. We also investigate the overrings of a ${\phi}$-PAVR.

A Study on the Vector Space by Taking the Tetra-cosine Rule (Tetra-cosine Rule 에 의한 Vector Space고찰)

  • 김건희;이수종;김홍건
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.389-394
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    • 1997
  • Consider a tetrhedron is composed of six dihedral angles .phi.(i=1,2..., 6), and a vertex of a tetrahedron is also three dihedral angles. It will assume that a vertex A, for an example, is composed of there angles definded such as .alpha..betha. and .gamma. !. then there is a corresponding angle can be given as .phi1.,.phi2.,.phi3.. Here, in order to differentiate between a conventional triangle and dihedral angle, if a dihedral angle degined in this paper is symbolized as .phi..LAMBDA.,the value of cos.theta.of .phi./sab a/, in a trigonometric function rule,can be defined to tecos.phi..LAMBD/sab A/., and it is defined as a tetradedral cosine .phi. or simply called a tecos.phi.. Moreover, in a simillar method, the dihedral angle of tetrahedron .phi..LAMBDA. is given as : value of sin .theta. can defind a tetra-sin.phi..LAMBDA., and value of tan .theta. of .phi..LAMBDA. is a tetra-tan .phi..LAMBDA. By induction it can derive that a tetrahedral geometry on the basis of suggesting a geometric tetrahedron

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REGULARITY OF GENERALIZED DERIVATIONS IN BCI-ALGEBRAS

  • Muhiuddin, G.
    • Communications of the Korean Mathematical Society
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    • v.31 no.2
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    • pp.229-235
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    • 2016
  • In this paper we study the regularity of inside (or outside) (${\theta},{\phi}$)-derivations in BCI-algebras X and prove that let $d_{({\theta},{\phi})}:X{\rightarrow}X$ be an inside (${\theta},{\phi}$)-derivation of X. If there exists a ${\alpha}{\in}X$ such that $d_{({\theta},{\phi})}(x){\ast}{\theta}(a)=0$, then $d_{({\theta},{\phi})}$ is regular for all $x{\in}X$. It is also shown that if X is a BCK-algebra, then every inside (or outside) (${\theta},{\phi}$)-derivation of X is regular. Furthermore the concepts of ${\theta}$-ideal, ${\phi}$-ideal and invariant inside (or outside) (${\theta},{\phi}$)-derivations of X are introduced and their related properties are investigated. Finally we obtain the following result: If $d_{({\theta},{\phi})}:X{\rightarrow}X$ is an outside (${\theta},{\phi}$)-derivation of X, then $d_{({\theta},{\phi})}$ is regular if and only if every ${\theta}$-ideal of X is $d_{({\theta},{\phi})}$-invariant.

COMPOSITION OPERATORS ON UNIFORM ALGEBRAS AND THE PSEUDOHYPERBOLIC METRIC

  • Galindo, P.;Gamelin, T.W.;Lindstrom, M.
    • Journal of the Korean Mathematical Society
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    • v.41 no.1
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    • pp.1-20
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    • 2004
  • Let A be a uniform algebra, and let $\phi$ be a self-map of the spectrum $M_A$ of A that induces a composition operator $C_{\phi}$, on A. It is shown that the image of $M_A$ under some iterate ${\phi}^n$ of \phi is hyperbolically bounded if and only if \phi has a finite number of attracting cycles to which the iterates of $\phi$ converge. On the other hand, the image of the spectrum of A under $\phi$ is not hyperbolically bounded if and only if there is a subspace of $A^{**}$ "almost" isometric to ${\ell}_{\infty}$ on which ${C_{\phi}}^{**}$ "almost" an isometry. A corollary of these characterizations is that if $C_{\phi}$ is weakly compact, and if the spectrum of A is connected, then $\phi$ has a unique fixed point, to which the iterates of $\phi$ converge. The corresponding theorem for compact composition operators was proved in 1980 by H. Kamowitz [17].

A NEW APPROXIMATION SCHEME FOR FIXED POINTSOF ASYMPTOTICALLY ø-HEMICONTRACTIVE MAPPINGS

  • Kim, Seung-Hyun;Lee, Byung-Soo
    • Communications of the Korean Mathematical Society
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    • v.27 no.1
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    • pp.167-174
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    • 2012
  • In this paper, we introduce an asymptotically $\phi$-hemicontractive mapping with a $\phi$-normalized duality mapping and obtain some strongly convergent result of a kind of multi-step iteration schemes for asymptotically $\phi$-hemicontractive mappings.

A GENERALIZATION OF THE PRIME RADICAL OF IDEALS IN COMMUTATIVE RINGS

  • Harehdashti, Javad Bagheri;Moghimi, Hosein Fazaeli
    • Communications of the Korean Mathematical Society
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    • v.32 no.3
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    • pp.543-552
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    • 2017
  • Let R be a commutative ring with identity, and ${\phi}:{\mathfrak{I}}(R){\rightarrow}{\mathfrak{I}}(R){\cup}\{{\varnothing}\}$ be a function where ${\mathfrak{I}}(R)$ is the set of all ideals of R. Following [2], a proper ideal P of R is called a ${\phi}$-prime ideal if $x,y{\in}R$ with $xy{\in}P-{\phi}(P)$ implies $x{\in}P$ or $y{\in}P$. For an ideal I of R, we define the ${\phi}$-radical ${\sqrt[{\phi}]{I}}$ to be the intersection of all ${\phi}$-prime ideals of R containing I, and show that this notion inherits most of the essential properties of the usual notion of radical of an ideal. We also investigate when the set of all ${\phi}$-prime ideals of R, denoted $Spec_{\phi}(R)$, has a Zariski topology analogous to that of the prime spectrum Spec(R), and show that this topological space is Noetherian if and only if ${\phi}$-radical ideals of R satisfy the ascending chain condition.

ON Φ-FLAT MODULES AND Φ-PRÜFER RINGS

  • Zhao, Wei
    • Journal of the Korean Mathematical Society
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    • v.55 no.5
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    • pp.1221-1233
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    • 2018
  • Let R be a commutative ring with non-zero identity and let NN(R) = {I | I is a nonnil ideal of R}. Let M be an R-module and let ${\phi}-tor(M)=\{x{\in}M{\mid}Ix=0\text{ for some }I{\in}NN(R)\}$. If ${\phi}or(M)=M$, then M is called a ${\phi}$-torsion module. An R-module M is said to be ${\phi}$-flat, if $0{\rightarrow}{A{\otimes}_R}\;{M{\rightarrow}B{\otimes}_R}\;{M{\rightarrow}C{\otimes}_R}\;M{\rightarrow}0$ is an exact R-sequence, for any exact sequence of R-modules $0{\rightarrow}A{\rightarrow}B{\rightarrow}C{\rightarrow}0$, where C is ${\phi}$-torsion. In this paper, the concepts of NRD-submodules and NP-submodules are introduced, and the ${\phi}$-flat modules over a ${\phi}-Pr{\ddot{u}}fer$ ring are investigated.