• Title/Summary/Keyword: NI near-ring

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TOPOLOGICAL CONDITIONS OF NI NEAR-RINGS

  • Dheena, P.;Jenila, C.
    • Communications of the Korean Mathematical Society
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    • v.28 no.4
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    • pp.669-677
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    • 2013
  • In this paper we introduce the notion of NI near-rings similar to the notion introduced in rings. We give topological properties of collection of strongly prime ideals in NI near-rings. We have shown that if N is a NI and weakly pm near-ring, then $Max(N)$ is a compact Hausdorff space. We have also shown that if N is a NI near-ring, then for every $a{\in}N$, $cl(D(a))=V(N^*(N)_a)=Supp(a)=SSpec(N){\setminus}int\;V(a)$.

A GENERALIZATION OF ARMENDARIZ AND NI PROPERTIES

  • Li, Dan;Piao, Zhelin;Yun, Sang Jo
    • Communications of the Korean Mathematical Society
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    • v.33 no.3
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    • pp.741-750
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    • 2018
  • Antoine showed that the properties of Armendariz and NI are independent of each other. The study of Armendariz and NI rings has been doing important roles in the research of zero-divisors in noncommutative ring theory. In this article we concern a new class of rings which generalizes both Armendariz and NI rings. The structure of such sort of ring is investigated in relation with near concepts and ordinary ring extensions. Necessary examples are examined in the procedure.

IFP RINGS AND NEAR-IFP RINGS

  • Ham, Kyung-Yuen;Jeon, Young-Cheol;Kang, Jin-Woo;Kim, Nam-Kyun;Lee, Won-Jae;Lee, Yang;Ryu, Sung-Ju;Yang, Hae-Hun
    • Journal of the Korean Mathematical Society
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    • v.45 no.3
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    • pp.727-740
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    • 2008
  • A ring R is called IFP, due to Bell, if ab=0 implies aRb=0 for $a,b{\in}R$. Huh et al. showed that the IFP condition need not be preserved by polynomial ring extensions. But it is shown that ${\sum}^n_{i=0}$ $E_{ai}E$ is a nonzero nilpotent ideal of E whenever R is an IFP ring and $0{\neq}f{\in}F$ is nilpotent, where E is a polynomial ring over R, F is a polynomial ring over E, and $a_i^{'s}$ are the coefficients of f. we shall use the term near IFP to denote such a ring as having place near at the IFPness. In the present note the structures of IFP rings and near-IFP rings are observed, extending the classes of them. IFP rings are NI (i.e., nilpotent elements form an ideal). It is shown that the near-IFPness and the NIness are distinct each other, and the relations among them and related conditions are examined.

Investigation of Characteristics for Cooling Parameters of a Combustor in Liquid Rocket Combustors (재생냉각 연소기의 냉각기구에 따른 특성 파악)

  • Kim, Hong-Jip;Choi, Hwan-Seok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.14 no.5
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    • pp.45-50
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    • 2010
  • Thermal analyses have been performed to study the effect of location of fuel ring and thermal barrier coatings in regenerative cooling channels in a full-scale combustor. For the effective cooling, the fuel ring has better be installed near axial location of the low expansion ratio and low heat flux, and branching of cooling channels is preferable. Also, the radiative cooled nozzle extension is thought to be reasonable for the cooling of combustor walls. Among the possible coatings, $Y_2O_3$ stabilized $ZrO_2$ coating and Ni/Cr coating have been adopted. Compared with Ni/Cr coating which has high oxidation resistance, $Y_2O_3$ stabilized $ZrO_2$ coating, one of ceramic coatings is found to be much effective to sustain the thermal survivability of combustion walls.

Regenerative Cooling Characteristics for Cooling Parameters of a Combustor in Liquid Rocket Combustors (재생냉각 연소기의 냉각기구에 따른 냉각 특성 파악)

  • Kim, Hong-Jip;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.145-149
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    • 2010
  • Thermal analyses have been performed to study the effect of location of fuel ring and thermal barrier coatings in regenerative cooling channels in a full-scale combustor. For the effective cooling, the fuel ring has better be installed near axial location of the low expansion ratio and low heat flux, and branching of cooling channels is preferable. Also, the radiative cooled nozzle extension is thought to be reasonable for the cooling of combustion walls. Among the possible coatings, $Y_2O_3$ stabilized $ZrO_2$ coating and Ni/Cr coating have been adopted. Compared with Ni/Cr coating which has high oxidation resistance, $Y_2O_3$ stabilized $ZrO_2$ coating, one of ceramic coatings is found to be much effective to sustain the thermal survivability of combustion walls.

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Synthesis and Structure Analysis of α and β Forms of [12] Metallacrown-6 Nickel(II) Complex: [Ni6(SCH2CH2CH3)12]

  • Xiao, Hai Lian;Jian, Fang Fang;Zhang, Ke Jie
    • Bulletin of the Korean Chemical Society
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    • v.30 no.4
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    • pp.846-848
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    • 2009
  • Two modifications of the ${\alpha}\;and\;{\beta}$ forms of propyl mercaptan nickel(II) cluster, [$Ni_6(SCH_2CH_2CH_3)_{12}$], have been synthesized and their crystal structures have been determined by single-crystal X-ray diffraction. The alkyl groups are away from $Ni_6$ ring in $\alpha$ form whereas they are near to the Ni atom in $\beta$ form. The distance of Ni-H in $\beta$ form [2.576(5) $\AA$] is much shorter than that in $\alpha$ form [3.101(2) $\AA$]. In the crystal lattice of $\beta$ form, the whole structure forms a flower shape.