• 대한수학회논문집
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• 제26권3호
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• pp.405-416
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• 2011

In this paper, we first introduce the concept of left strongly simple po-semigroups, then we discuss properties and characterizations nil-extensions of left strongly simple po-semigroups and semilattices of leftstrongly simple po-semigroups. Finally, we give some characterizations of the chain of left strongly simple po-semigroups.

• Kyungpook Mathematical Journal
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• 제56권3호
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• pp.861-866
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• 2016

A ring R called left SF if its simple left modules are at. Regular rings are known to be left SF-rings. However, till date it is unknown whether a left SF-ring is necessarily regular. In this paper, we prove the strong regularity of left (right) complement bounded left SF-rings. We also prove the strong regularity of a class of generalized semi-commutative left SF-rings.

• Kyungpook Mathematical Journal
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• 제53권3호
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• pp.397-406
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• 2013

A ring R is called a left (right) SF-ring if simple left (right) R-modules are flat. It is still unknown whether a left (right) SF-ring is von Neumann regular. In this paper, we give some conditions for a left (right) SF-ring to be (a) von Neumann regular; (b) strongly regular; (c) division ring. It is proved that: (1) a right SF-ring R is regular if maximal essential right (left) ideals of R are weakly left (right) ideals of R (this result gives an affirmative answer to the question raised by Zhang in 1994); (2) a left SF-ring R is strongly regular if every non-zero left (right) ideal of R contains a non-zero left (right) ideal of R which is a W-ideal; (3) if R is a left SF-ring such that $l(x)(r(x))$ is an essential left (right) ideal for every right (left) zero divisor x of R, then R is a division ring.

• 대한수학회보
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• 제43권2호
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• pp.299-307
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• 2006

The following results ale extended from P-injective rings to AP-injective rings: (1) R is left self-injective regular if and only if R is a right (resp. left) AP-injective ring such that for every finitely generated left R-module M, $_R(M/Z(M))$ is projective, where Z(M) is the left singular submodule of $_{R}M$; (2) if R is a left nonsingular left AP-injective ring such that every maximal left ideal of R is either injective or a two-sided ideal of R, then R is either left self-injective regular or strongly regular. In addition, we answer a question of Roger Yue Chi Ming [13] in the positive. Let R be a ring whose every simple singular left R-module is Y J-injective. If R is a right MI-ring whose every essential right ideal is an essential left ideal, then R is a left and right self-injective regular, left and right V-ring of bounded index.

• 대한수학회보
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• 제40권2호
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• pp.223-234
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• 2003

This note contains the following results for a ring A : (1) A is simple Artinian if and only if A is a prime right YJ-injective, right and left V-ring with a maximal right annihilator ; (2) if A is a left quasi-duo ring with Jacobson radical J such that $_{A}$A/J is p-injective, then the ring A/J is strongly regular ; (3) A is von Neumann regular with non-zero socle if and only if A is a left p.p.ring containing a finitely generated p-injective maximal left ideal satisfying the following condition : if e is an idempotent in A, then eA is a minimal right ideal if and only if Ae is a minimal left ideal ; (4) If A is left non-singular, left YJ-injective such that each maximal left ideal of A is either injective or a two-sided ideal of A, then A is either left self-injective regular or strongly regular : (5) A is left continuous regular if and only if A is right p-injective such that for every cyclic left A-module M, $_{A}$M/Z(M) is projective. ((5) remains valid if 《continuous》 is replaced by 《self-injective》 and 《cyclic》 is replaced by 《finitely generated》. Finally, we have the following two equivalent properties for A to be von Neumann regula. : (a) A is left non-singular such that every finitely generated left ideal is the left annihilator of an element of A and every principal right ideal of A is the right annihilator of an element of A ; (b) Change 《left non-singular》 into 《right non-singular》in (a).(a).

• 대한수학회보
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• 제20권1호
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• pp.45-49
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• 1983

If R is ring and M is a right (or left) R-module, then M is called a faithful R-module if, for some a in R, x.a=0 for all x.mem.M then a=0. In [4], R.E. Johnson defines that M is a prime module if every non-zero submodule of M is faithful. Let us define that M is of prime type provided that M is faithful if and only if every non-zero submodule is faithful. We call a right (left) ideal I of R is of prime type if R/I is of prime type as a R-module. This is equivalent to the condition that if xRy.subeq.I then either x.mem.I ro y.mem.I (see [5:3:1]). It is easy to see that in case R is a commutative ring then a right or left ideal of a prime type is just a prime ideal. We have defined in [5], that a chain of right ideals of prime type in a ring R is a finite strictly increasing sequence I$_{0}$.contnd.I$_{1}$.contnd....contnd.I$_{n}$; the length of the chain is n. By the right dimension of a ring R, which is denoted by dim, R, we mean the supremum of the length of all chains of right ideals of prime type in R. It is an integer .geq.0 or .inf.. The left dimension of R, which is denoted by dim$_{l}$ R is similarly defined. It was shown in [5], that dim$_{r}$R=0 if and only if dim$_{l}$ R=0 if and only if R modulo the prime radical is a strongly regular ring. By "a strongly regular ring", we mean that for every a in R there is x in R such that axa=a=a$^{2}$x. It was also shown that R is a simple ring if and only if every right ideal is of prime type if and only if every left ideal is of prime type. In case, R is a (right or left) primitive ring then dim$_{r}$R=n if and only if dim$_{l}$ R=n if and only if R.iden.D$_{n+1}$ , n+1 by n+1 matrix ring on a division ring D. in this paper, we establish the following results: (1) If R is prime ring and dim$_{r}$R=n then either R is a righe Ore domain such that every non-zero right ideal of a prime type contains a non-zero minimal prime ideal or the classical ring of ritght quotients is isomorphic to m*m matrix ring over a division ring where m.leq.n+1. (b) If R is prime ring and dim$_{r}$R=n then dim$_{l}$ R=n if dim$_{l}$ R=n if dim$_{l}$ R<.inf. (c) Let R be a principal right and left ideal domain. If dim$_{r}$R=1 then R is an unique factorization domain.TEX>R=1 then R is an unique factorization domain.

• 한국수정란이식학회지
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• 제26권2호
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• pp.141-145
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• 2011

Seven male Himalayan tahrs were strongly assumed to have accidently fed on foreign bodies in 2007. At the time, zoo caretakers witnessed missing fence padding, such as carpet, plastic awning, and ropes. The incident occurred the morning after the items had been set up to protect indigenous, wild long-tailed gorals from self injury caused by head butting the steel fence. Adult male Himalayan tahrs were obviously suspected of mostly eating the paddings mainly composed of carpet, thin and long plastic awning, and ropes. Even though they had not shown digestive problems, surgery was determined necessary in order to remove any indigestible foreign bodies. Left flank rumenotomy was conducted on seven male Himalayan tahrs from April to May, 2011. After anesthesia with xylazine, rumenotomy was performed on a concrete floor, with legs and head secured by ropes. No access to water and hay prior to operation for two days was needed to make the surgical procedure done quickly. Two sheets of small hand towels protecting against inflow of ruminal contents were beneficial during surgery. Antibiotics were administered intramuscularly for seven days. No abscesses at the surgical site were found after surgery. Like domestic ruminants, wild ruminants also ingest metalic or non-metalic, indigestible foreign bodies by accident. Therefore, simplified rumenotomy must be developed to apply to those wild animals to lengthen their longevity and to advance the quality of life in captivity. This case report is the first showing how to perform rumenotomy of Himalayan tahr, a wild ruminant, in Korea.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.430-430
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• 2007

In general, polyimides (PIs) are used in liquid crystal displays (LCDs) as alignment layer of liquid crystals (LCs). Up to date, the rubbing alignment technique has been widely used to align liquid crystals on the PI surface, which is suitable for mass-production of LCDs because of its simple process and high productivity. However, this method has some disadvantages. Rubbed PI surfaces include the debris left by the cloth and the generation of electrostatic charges during rubbing process. Therefore, rubbing-free techniques for LC alignment are strongly required in LCD technology. In this experiment, PI was uniformly coated on indium-tin-oxide electrode substrates to form LC alignment layers using a spin-coating method and the PI layers were subsequently imidized at 433 K for 1 h. The thickness of the PI layer was set at 50 nm. The LC alignment layer surfaces were exposed to an $Ar^+$ ion-beam under various ion-beam energies. The antiparallel cells and twisted-nematic (TN) cells for the measurement of pretile angle and electro-optical characteristics were fabricated with the cell gap of 60 and $5\;{\mu}m$, respectively. The LC cells were filled with nematic LC (NLC, MJ001929, Merck) and were assembled. The NLC alignment capability on ion-beam-treated PI was observed using photomicroscope and the pretilt angle of the NLC was measured by the crystal-rotation method at room temperature. Voltage-transmittance (V-T) and response time characteristics of the ion-beam irradiated TN cell were measured by a LCD evaluation system.

• Tuberculosis and Respiratory Diseases
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• 제44권2호
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• pp.401-408
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• 1997

연구배경 : 폐격리증은 드문 선천성 폐질환으로 진단이 지연되거나 오진되는 경우가 많은 것으로 알려져 있으며, 수술전에 진단이 되지 않은 경우에는 수술시 이상동맥으로부터의 출혈로 인하여 어려움을 겪게 되는 경우가 있다. 저자 등은 수술적 치험을 한 폐격리증의 진단과 치료 등에 관한 전반적인 임상적 고찰을 시행하고자 한다. 방 법 : 1991년부터 1996년 5월까지 수술로써 확인된 15예의 폐격리증 환자를 대상으로 임상소견, 수술전 진단, 방사선 및 수술소견, 예후 등에 관하여 조사하였다. 결 과 : 평균연령은 22.5세(범위 5~57세)였고, 남녀비는 9 : 6이었다. 증상은 주로 재발성의 발열, 기침, 흉통, 객담 등의 감염증세를 나타내었으며, 내엽형 3예는 증상 없이 우연히 발견되었다. 단순 흉부 방사선 소견상 10예에서 다낭성 음영으로 나타났고, 5예에서 종괴양 음영이 관찰되었다. 흉부 전산화 단층촬영은 12예에서 시행되었는데, 8예에서 다낭성 음영이, 4예에서 종괴양 음영이 관찰되었다. 흉부 자기공명영상은 3예에서 시행되었는데, 2예에서 하행대동맥에서 기시하는 이상동맥을 확인할 수 있었다. 대동맥 조영술은 4예에서 시행되었고, 이상동맥은 2예에서는 하행 흉부대동맥, 1예는 복부대동맥, 1예는 늑간동맥에서 기시하였고, 모두 폐정맥으로 환류 되었다. 수술전 진단에 있어서는 폐격리증으로 진단한 경우는 내엽형 6예였고, 폐종양이 3예, 폐종양이 2예, 기관지 확장증이 2예 그리고 종격동 종양이 2예였다. 수술소견상으로는 내엽형이 12예중 8예는 좌하엽, 2예는 우하엽, 1예는 좌상엽, 1예는 우중엽에 위치하였고, 외엽형 3예중 2예는 좌우 횡격막 상부, 1예는 심낭내에 위치하였다. 수술시 이상동맥은 6예는 하행 흉부대동맥, 1예는 복부 대동맥, 2예는 내흉동맥, 1예는 늑간동맥, 1예는 심낭횡격막동맥에서 기시한 것으로 확인되었고, 4예에서는 정확한 기시부를 확인하지 못 하였다. 수술사망 및 이환률은 없었고, 추적관찰상 모두 특별한 문제없이 지내고 있다. 결 론 : 폐격리증 환자의 임상 양상은 다른 보고들과 유사한 소견을 보였고, 수술전 진단률은 비교적 낮았으며, 특히 외엽형의 경우에 더 낮은 경향을 보였다. 본 연구에서는 전 예에서 합병증 없이 양호한 경과를 보였으나, 향후 더 적극적인 수술전 진단적 접근을 하는 것이 수술시 출혈 등의 합병증 방지 및 적절한 수술방법의 적용에 도움이 될 것으로 사료된다.