• 산업기술연구
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• 제27권B호
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• pp.145-151
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• 2007

In this paper, a BPF with a dual mode folded ring resonator is presented. The dual mode ring resonator is also exactly analyzed by using Y-parameter method, in which the difference in admittance of two lines make the ring resonator work as a dual mode resonator. The proposed BPF has an advantage of small size compared to conventional one with dual mode ring resonator.

• Kyungpook Mathematical Journal
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• 제57권3호
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• pp.419-431
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• 2017

In this paper, we define a new kind of formal power series rings by using Gaussian binomial coefficients and investigate some properties. More precisely, we call such a ring a Gaussian series ring and study McCoy's theorem, Hermite properties and Noetherian properties.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1992년도 제3회 학술발표회 논문개요집
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• pp.113-114
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• 1992

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 제9회 단조 심포지엄
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• pp.89-94
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• 2004

Profile ring rolling process for large slewing rings of alley steels are developed. A profile ring with a round groove located asymmetrically on the outer surface is rolled. The process is simulated by the finite element method. The general-purpose commercial finite element analysis software, MSC.Superform, was used. Experiments are carried in the ring rolling machine and compared with the analysis.

• Kyungpook Mathematical Journal
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• 제61권3호
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• pp.461-472
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• 2021

We study a new ring property called axis-commutativity. Axis-commutative rings are seated between commutative rings and duo rings and are a generalization of division rings. We investigate the basic structure and several extensions of axis-commutative rings.

• 대한수학회보
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• 제59권5호
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• pp.1317-1325
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• 2022

In this note, we prove that an Artinian local ring is G-semisimple (resp., SG-semisimple, 2-SG-semisimple) if and only if its maximal ideal is G-projective (resp., SG-projective, 2-SG-projective). As a corollary, we obtain the global statement of the above. We also give some examples of local G-semisimple rings whose maximal ideals are n-generated for some positive integer n.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.357-360
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• 2007

The profile ring rolling process of Ti-6Al-4V alloy was designed by finite element(FE) simulation and experimental analysis. The design includes geometry design and optimization of process variables. The geometry design such as initial billet and blank sizes, and final rolled ring shape was carried out with the calculation method based on the uniform deformation concept between the wall thickness and ring height. FEM simulation was used to calculate the state variables such as strain, strain rate and temperature and to predict the formation of forming defects during ring rolling process. Finally, the mechanical properties of profiled Ti-6Al-4V alloy ring product were analyzed with the evolution of microstructures during the ring rolling process.

• KSTLE International Journal
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• 제2권2호
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• pp.127-132
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• 2001

The steady state performance of the counterrotating floating ring journal bearings is analyzed with isothermal finite bearing theory. The effect of counterrotating speed of the sleeve on the performance of the bearing is investigated. It is shown that counterrotating floating ring journal bearings can have considerable load capacity at the same counterrotating speeds, while conventional circular journal bearings with one fluid film cannot. Investigating the relationship between the frictional torques exerted on the ring due to the inner and outer films and the rotational speed of the ring, the stability of the equilibrium state is identified and the operating characteristics of the counterrotating floating ring journal bearing according to the method of acceleration or deceleration of the rotational speeds of the journal and sleeve are clarified. It is theoretically confirmed that floating ring journal bearings can be used in counterrotating journal-bearing system and become good substitutes for rolling bearings in counterrotating systems.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제29회 춘계학술대회
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• pp.232-239
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• 1999

Generally quantity of supply oil for piston ring lubrication in an internal combustion engine may be insufficient to fill the entire volume formed in the clearance between piston ring and cylinder liner. Thus oil starvation condition should be considered for the analysis of piston ring lubrication. In order to reasonably estimate amount of oil left on the cylinder liner, adequate boundary condition should be adapted for the analysis of ring pack lubrication. In this analysis of ring pack lubrication of an internal combustion engine, oil starvation and open-end boundary conditions are considered at inlet and outlet of piston rings. It is revealed that piston rings are operated under oil starvation in most operating cycle and the result with these conditions are quite different from that with fully-flooded assumption.

• 대한수학회지
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• 제50권5호
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• pp.959-972
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• 2013

Rege-Chhawchharia, and Nielsen introduced the concept of right McCoy ring, based on the McCoy's theorem in 1942 for the annihilators in polynomial rings over commutative rings. In the present note we concentrate on a natural generalization of a right McCoy ring that is called a right nilpotent coefficient McCoy ring (simply, a right NC-McCoy ring). The structure and several kinds of extensions of right NC-McCoy rings are investigated, and the structure of minimal right NC-McCoy rings is also examined.