• Communications of the Korean Mathematical Society
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• v.31 no.2
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• pp.237-246
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• 2016

The purpose of this paper is to introduce some new class of rings that are closely related to the classes of sharp domains, pseudo-Dededkind domains, TV domains and finite character domains. A ring R is called a ${\phi}$-sharp ring if whenever for nonnil ideals I, A, B of R with $I{\supseteq}AB$, then I = A'B' for nonnil ideals A', B' of R where $A^{\prime}{\supseteq}A$ and $B^{\prime}{\supseteq}B$. We proof that a ${\phi}$-Dedekind ring is a ${\phi}$-sharp ring and we get some properties that by them a ${\phi}$-sharp ring is a ${\phi}$-Dedekind ring.

• Bulletin of the Korean Mathematical Society
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• v.48 no.3
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• pp.469-474
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• 2011

The Kauffman bracket skein module $K_t$(M) of a 3-manifold M becomes an algebra for t = -1. We prove that this algebra has no non-trivial nilpotent elements for M being the exterior of the twist knot in 3-sphere and, therefore, it is isomorphic to the $SL_2(\mathbb{C})$-character ring of the fundamental group of M. Our proof is based on some properties of Chebyshev polynomials.

• Kyungpook Mathematical Journal
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• v.61 no.3
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• pp.487-494
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• 2021

In this paper, we study rings with Noetherian spectrum, rings with locally Noetherian spectrum and rings with t-locally Noetherian spectrum in terms of the polynomial ring, the Serre's conjecture ring, the Nagata ring and the t-Nagata ring. In fact, we show that a commutative ring R with identity has Noetherian spectrum if and only if the Serre's conjecture ring R[X]_U has Noetherian spectrum, if and only if the Nagata ring R[X]_N has Noetherian spectrum. We also prove that an integral domain D has locally Noetherian spectrum if and only if the Nagata ring D[X]_N has locally Noetherian spectrum. Finally, we show that an integral domain D has t-locally Noetherian spectrum if and only if the polynomial ring D[X] has t-locally Noetherian spectrum, if and only if the t-Nagata ring $D[X]_{N_v}$ has (t-)locally Noetherian spectrum.

• Journal of environmental and Sanitary engineering
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• v.15 no.4
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• pp.4-13
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• 2000

산업공정에서 배출되는 대기오염물질 및 유독성가스를 제거하기 위한 방법에는 여러 가지가 적용되고 있으나, 본 연구에서는 충전탑을 이용한 흡수원리로써 오염물질을 처리하는데 후력학적 특성에 대해서 연구하였다. 즉 환경보호와 화학공업에서 에너지 절약 측면에 충전탑의 사용이 증가되고 있으며, 충전물의 재료로는 플라스틱, 금속 및 세라믹 등으로 제작되며 종류로는 VSP-ring, Hiflow-ring, Hackette, Top-packing, Envi-pac 등이 있고 사용범위는 정류와 증류, 흡수 및 탈착과 액체와 액체의 추출공정 등에 효율적으로 사용되고 있다. 산업현장에서는 과거에 주로 사용되어온 Intalox-saddle, Rasching-ring, Pall-ring 등의 재래적 충전물은 압력손실과 물질전달, 에너지 절약 및 효율성이 좋은 격자형 충전물의 개발로 인하여 점점 사용이 감소되고 있는 추세이며, 최근에는 합성수지로 제조된 충전물 NSW-ring, Hiflow-ring, Envi-pac 등은 실험 결과에 의해서 재래적인 충전물 Raschig-ring과 Pall-ring보다 높은 상대적인 공간체적과 충전높이에 따른 낮은 압력손실과 함께 높은 부하 한계치에 대하여 효율적이고 가벼운 분리작용에 의한 수력학적 특성이 증명되어졌다. 격자형 충전물이 산업에 적용되기 위해서는 압력손실과 액체함량, 부하 한계치 가스상 또는 액상 물질전달의 특성을 규명하는 것이 중요하다. 따라서 본 연구에서는 가수와 액체의 역류흐름에 의한 수력학적 특성과 물질전달 실험결과를 나타내었다.

• Korean Journal of Cognitive Science
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• v.3 no.1
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• pp.139-160
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• 1991

• Kyungpook Mathematical Journal
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• v.55 no.3
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• pp.507-514
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• 2015

Let D be an integral domain, t be the so-called t-operation on D, and S be a (not necessarily saturated) multiplicative subset of D. In this paper, we study the Nagata ring of S-Noetherian domains and locally S-Noetherian domains. We also investigate the t-Nagata ring of t-locally S-Noetherian domains. In fact, we show that if S is an anti-archimedean subset of D, then D is an S-Noetherian domain (respectively, locally S-Noetherian domain) if and only if the Nagata ring $D[X]_N$ is an S-Noetherian domain (respectively, locally S-Noetherian domain). We also prove that if S is an anti-archimedean subset of D, then D is a t-locally S-Noetherian domain if and only if the polynomial ring D[X] is a t-locally S-Noetherian domain, if and only if the t-Nagata ring $D[X]_{N_v}$ is a t-locally S-Noetherian domain.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.121-122
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• 2002

This paper presents contact behavior of an Polyperfluoroalkoxyethylene(PTFE) ring seals by a non-linear finite element method using the thermomechanical analysis. PTFE elastomer was assumed as odgen model for numerical analysis in FEM commercial code because elastomer has nonlinear behaviour character. The shape effects are investigated for sealing performance of ring seal in boundary conditions which as gas pressure, groove temperature and various O-ring seal models. Also contact stress and equivalent total strain are investicated. An O-ring seals was modeled four shape which are circle, two sunflower and X. The highest contact stress occurs at sunflower-ring seal with groove deapth of 0.35mm. the equivalent total strain of sunflower-ring seal is lower than that of the others under low gas pressure condition but under gas pressure condition over 4Mpa, that of sunflower-ring seal is higher. The calculated FEM results shows that the Sunflower-ring seal with groove depth of 0.35mm has excellent performance compared with other seal models.

• Bulletin of the Korean Mathematical Society
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• v.57 no.4
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• pp.973-990
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• 2020

For the question "when is E(_RR) a flat left R-module for any ring R?", in this paper, we deal with a class of modules partaking in the hierarchy of injective and cotorsion modules, so-called Harmanci injective modules, which turn out by the motivation of relations among the concepts of injectivity, flatness and cotorsionness. We give some characterizations and properties of this class of modules. It is shown that the class of all Harmanci injective modules is enveloping, and forms a perfect cotorsion theory with the class of modules whose character modules are Matlis injective. For the objective we pursue, we characterize when the injective envelope of a ring as a module over itself is a flat module.

• Journal of applied mathematics & informatics
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• v.38 no.3_4
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• pp.271-276
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• 2020

Let R be a commutative ring with identity, R[X] the polynomial ring over R, ∗ a radical operation on R and ⋆ a radical operation of finite character on R[X]. In this paper, we give Hilbert basis theorem for rings with ∗-Noetherian spectrum. More precisely, we show that if (I^∗R[X])^⋆ = (IR[X])^⋆ and (I^∗R[X])^⋆ ∩ R = I^∗ for all ideals I of R, then R has ∗-Noetherian spectrum if and only if R[X] has ⋆-Noetherian spectrum. This is a generalization of a well-known fact that R has Noetherian spectrum if and only if R[X] has Noetherian spectrum.

• Journal of Technologic Dentistry
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• v.21 no.1
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• pp.77-85
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• 1999

When producing partial denture using a Chrome-cobalt alloy being used universally, 45 pattern of them to compare casting characters according to 5 burying methods(special ring method, plastic ring method, general metal ring method) and 5 casting directions(straight, upper, lower, left and right directions) were compared and evaluated. The results were as follows : 1. The comparison of casting characters in accordance with burying type shows that the special ring method to install blind air vent using utility wax was the highest rate of 76.9%, followed by 69.1% of the plastic ring to cast without ring and 61.1% of the metal ring method being used universally respectively. Namely the special ring method was best. The significant level was P<0.05 statistically. 2. The comparison of casting character in accordance with casting directions shows that the straight casting was the highest of 77.9%, and followed by right casting of 74.2%, left casting of 66.7%, upper casting of 63.5%, and lower casting of 62.9% respectively, Namely the straight casting was best.