• 대한수학회논문집
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• 제34권1호
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• pp.127-136
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• 2019

This article concerns the normal property of elements on Jacobson and nil radicals which are generalizations of commutativity. A ring is said to be right njr if it satisfies the normal property on the Jacobson radical. Similarly a ring is said to be right nunr (resp., right nlnr) if it satisfies the normal property on the upper (resp., lower) nilradical. We investigate the relations between right duo property and the normality on Jacobson (nil) radicals. Related examples are investigated in the procedure of studying the structures of right njr, nunr, and nlnr rings.

• 충청수학회지
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• 제33권3호
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• pp.327-337
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• 2020

This article continues the study of right 𝜋-duo rings, concentrating on the situation of nonzero powers. For this purpose we introduce the concept of strongly right 𝜋-duo and examine the structure of strongly right 𝜋-duo in relation to various ring properties that play important roles in ring theory. It is proved for a strongly right 𝜋-duo ring R that if the upper (lower) nilradical of R is zero then R is reduced. Various kinds of examples are examined in relation to the questions raised in the procedure.

• 한국정보기술학회논문지
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• 제17권3호
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• pp.43-50
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• 2019

본 논문에서는 수직 분할 링 공진기(VSRR, Vertical Split Ring Resonator)를 적용하여 전기적 크기를 축소시킨 발진기를 제안하였다. VSRR은 유전체 기판의 상면과 하면에 일렬로 놓인 마이크로스트립 라인간에 발생하는 커패시턴스와 인덕턴스에 의해서 공진기로 동작하는 분리형 링 공진기(Split Ring Resonator)형태이며, 마이크로스트립 라인을 이용한 일반적인 hairpin 형태 또는 평면형 링 공진기에 비해 공진 회로의 전기적 크기를 축소할 수 있는 장점이 있다. 본 논문에서는 S-band에서 동작하는 VSRR을 설계하고, 이를 공진회로로 사용한 발진기를 설계 및 구현한 결과를 제시하였다. 제안된 발진기는 2.4GHz에서 5.9dBm의 출력을 나타내었으며, 오프셋 주파수 100kHz에서 -112.58dBc@Hz, 1MHz에서 -137.36dBc@Hz의 위상잡음 특성을 나타내었다.

• Archives of Pharmacal Research
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• 제8권3호
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• pp.99-107
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• 1985

The interaction of reduced riboflavin 2', 3', 4', 5'-tetrabutyrate with salicylic acid, aspirin, and salicylamide has been spectroscopically investigated to determine the binding mechanism. Hydrogen-1 and carbon-13 unclear magnetic resonance, infrared, and absoption spectra were measured in chloform-d and chloroform. The association of the reduced riboflavin with salicylic acid derivatives is different from that osidizd one. Salicylic acid and the reduced riboflavin form a cyclic hydrogen bounded complex through the imino (3-N, 5-N) protons and the carbonyl (2-C, 4-C) oxygens of the isolloxazine ring of the latter, and the carboxylic hydroxyl proton and carbonyl oxygen of the former. Aspirin and the reduced riboflavin form a complex by the same mode as salicylic acid. Salicylamide forms a cyclic hydrogen bonded complex with the reduced riboflavin through the imino (3-N, 5-N) protons and the carbonyl (2-C, 4-C) oxygens of the isoalloxazine ring, and the amino proton and the carbonyl oxygen of salic aylmide. It appears that both the oxidized and reduced form of riboflavin are associated with salicylic acid derivatives.

• Journal of electromagnetic engineering and science
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• 제15권2호
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• pp.120-122
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• 2015

This study presents a new, simple method for improving the front-to-back (F/B) ratio of a microstrip patch antenna (MSA) based on surface wave suppression. The back radiation of the MSA is significantly reduced by using the meandered ground plane edges and placing split-ring resonators (SRRs) in the middle of the meandered slots. By loading SRRs near the center of the meandered ground plane edges, some parts of the diffracted back-lobe power density can be reduced further. Compared to the F/B ratio of a conventional MSA with a full ground plane of the same size, an improved F/B ratio of 18 dB has been achieved experimentally for our proposed MSA.

• 대한기계학회논문집A
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• 제25권8호
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• pp.1183-1188
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• 2001

This paper reports on the starved lubrication for the piston ring. In this analysis, two types of inlet boundary conditions, fully flooded and starved condition, are considered at the leading edge. The inlet position of effective lubrication and squeeze term are obtained by numerically iterative method. The effective lubricated region is reduced due to the starved condition at the inlet. The starved condition at the inlet significantly reduced the minimum oil film thickness(MOFT) at the midstroke of piston, and the friction force is also increased due to the thin oil film thickness. In the starved conditions, the power loss is significantly increased.

• Kyungpook Mathematical Journal
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• 제60권2호
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• pp.307-318
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• 2020

This article concerns the class of rings which satisfy the property of inserting regular elements at zero products, and rings with such property are called regular-IFP. We study the structure of regular-IFP rings in relation to various ring properties that play roles in noncommutative ring theory. We investigate conditions under which the regular-IFPness pass to polynomial rings, and equivalent conditions to the regular-IFPness.

• 대한수학회지
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• 제53권1호
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• pp.217-232
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• 2016

We make a study of two generalizations of regular rings, concentrating our attention on the structure of idempotents. A ring R is said to be right attaching-idempotent if for $a{\in}R$ there exists $0{\neq}b{\in}R$ such that ab is an idempotent. Next R is said to be generalized regular if for $0{\neq}a{\in}R$ there exist nonzero $b{\in}R$ such that ab is a nonzero idempotent. It is first checked that generalized regular is left-right symmetric but right attaching-idempotent is not. The generalized regularity is shown to be a Morita invariant property. More structural properties of these two concepts are also investigated.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.197-201
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• 2006

Folded lines are applied to design a compact microstrip ring hybrid. Using the proposed structure we achieve both significant size reduction and good harmonic suppression with the same results of conventional ring hybrid at 2.41GHz. Including the third harmonic frequency, up to 11GHz band harmonics are suppressed to -20dB. The size of the proposed ring-hybrid is reduced to one forth of the conventional ring hybrid. The measured frequency responses agree well with simulated ones.

• 대한수학회논문집
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• 제30권4호
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• pp.363-377
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• 2015

Let R be a ring, (S,${\leq}$) a strictly ordered monoid and ${\omega}$ : S ${\rightarrow}$ End(R) a monoid homomorphism. The skew generalized power series ring R[[S,${\omega}$]] is a common generalization of (skew) polynomial rings, (skew) power series rings, (skew) Laurent polynomial rings, (skew) group rings, and Mal'cev-Neumann Laurent series rings. In this paper, we investigate the interplay between the ring-theoretical properties of R[[S,${\omega}$]] and the graph-theoretical properties of its zero-divisor graph ${\Gamma}$(R[[S,${\omega}$]]). Furthermore, we examine the preservation of diameter and girth of the zero-divisor graph under extension to skew generalized power series rings.