• Kyungpook Mathematical Journal
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• 제18권1호
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• pp.23-29
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• 1978

In [7) Scott has defined C-formation radical for a class C of near rings and has studied its porperties under chain conditions. A natural question that arises is: Does there exist a Lower C-Formation radical class L(M) containing a given class M of ideals of near rings in C? In this paper we answer this by giving. two constructions for L(M) and prove that prime radical is hereditary.

• 대한수학회논문집
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• 제27권3호
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• pp.483-488
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• 2012

In this paper we introduce the notion of P-strongly regular near-ring. We have shown that a zero-symmetric near-ring N is P-strongly regular if and only if N is P-regular and P is a completely semiprime ideal. We have also shown that in a P-strongly regular near-ring N, the following holds: (i) $Na$ + P is an ideal of N for any $a{\in}N$. (ii) Every P-prime ideal of N containing P is maximal. (iii) Every ideal I of N fulfills I + P = $I^2$ + P.

• Kyungpook Mathematical Journal
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• 제28권1호
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• pp.39-44
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• 1988

In 1940, B. H. Neumann, working with a system more general than a near-field, proved that the additive group of such a system (and of a near-field) is commutative. The algebraic structure he used is known as a Neumann system (N-system). Here, the prime N-systems are classified and for each possible characteristic, examples of N-systems which are neither near-fields nor rings are given. It is also shown that a necessary condition for the set of all odd polynomials over GF(p) to be an N-system is that p is a Fermat prime.

• 대한수학회보
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• 제46권6호
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• pp.1051-1060
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• 2009

In this paper, we give topological properties of collection of prime ideals in 2-primal near-rings. We show that Spec(N), the spectrum of prime ideals, is a compact space, and Max(N), the maximal ideals of N, forms a compact $T_1$-subspace. We also study the zero-divisor graph $\Gamma_I$(R) with respect to the completely semiprime ideal I of N. We show that ${\Gamma}_{\mathbb{P}}$ (R), where $\mathbb{P}$ is a prime radical of N, is a connected graph with diameter less than or equal to 3. We characterize all cycles in the graph ${\Gamma}_{\mathbb{P}}$ (R).

• Kyungpook Mathematical Journal
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• 제60권2호
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• pp.415-421
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• 2020

In the proof of Theorem 3 on p.253 in [4], both right and left distributivity are assumed simultaneously which makes the proof invalid. We give a corrected proof for this theorem by introducing an extension of Lemma 2.2 in [2].

• Kyungpook Mathematical Journal
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• 제19권2호
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• pp.205-211
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• 1979

In this paper we continue the study of formation radical (F-radical) classes initiated in [3]. Hereditary and stronger properties of F-radical classes are discussed by giving construction for lower hereditary, lower stronger and lower strongly hereditary F-radical classes containing a given class M. It is shown that the Baer F-radical B is the lower strongly hereditary F-radical class containing the class of all nilpotent ideals and it is the upper radical class with $\{(I,\;N){\mid}N{\in}C,\;N\;is\;prime\}{\subset}SB$ where SB denotes the semisimple F-radical class of B and C is an arbitrary but fixed class of homomorphically closed near-rings. The existence of a largest F-radical class contained in a given class is examined using the concept of complementary F-radical introduced by Scott [5].

• 전기전자학회논문지
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• 제11권4호
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• pp.235-238
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• 2007

2차원 소자 시뮬레이터인 TMA 메디치를 이용하여 필드링와 깊은 접합 필드링에 대해 연구하였다. 이온 주입될 위치를 미리 트랜치 식각을 시킴으로써 항복전압 특성을 향상시킬 수 있었다. 시뮬레이션 결과 기존 필드링의 항복전압대비 깊은 접합 필드링 항복전압은 약 30%의 증가를 보였다. 깊은 접합 필드링은 같은 면적을 차지하는 조건하에서 설계 및 제작이 비교적 용이하고, 표면 전하의 영향도 적은 것으로 나타났다. 본 논문에서는 여러 분석을 통해 깊은 접합 필드링의 향상된 특성을 논하였다.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.56-64
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• 2000

A friction force measurement system using the floating liner method was developed to study the frictional behavior of piston rings. The measurement system was carefully designed to control the effect of the piston secondary motion and the temperature of cylinder wall and oil. The friction force between the barrel shaped piston ring and the cylinder liner, was measured under the condition of flooded oil supply. The measured friction forces were classified into five frictional modes with regard to the combination of predominant lubrication regimes(boundary, mixed and hydrodynamic lubrication) and stroke regions(midstroke and dead centers). The modes could be identified on the Stribeck diagram of the friction coefficients and the dimensionless number of ㎼/p, where the friction coefficients are evaluated at near the midstroke and dead centers.

• 한국패류학회지
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• 제29권2호
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• pp.121-127
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• 2013

본 연구에서는 신석기시대의 서산 대죽리 패총에서 출토된 말백합의 패각에 나타난 윤문을 판독하여 성장식을 추정하고 현재의 말백합 개체군과의 성장을 비교하였다. 패총 출토 패각의 수는 총 206개체였다. 각 연령군별로 각장과 윤경 간에 대응성을 보였고, 각 윤문군이 비교적 뚜렷이 구분되어 윤문판독의 타당성이 확인되어 판독된 윤문을 연륜으로 간주하였다. 패총 출토 말백합의 윤문은 2-5개까지 확인되어 2-5세군으로 구성되었음을 알 수 있었다. 패총 개체군의 성장식은 $SL_t=102.9025[1-e^{-0.18657(t+1.0906)}]$ 이었으며, 현생 개체군은 $SL_t=104.2583[1-e^{-0.2277(t+0.7499)}]$ 이었다. 각장 (SL) 과 각고 (SH) 간의 상대성장식은 패총 개체군 SH = 0.7791SL + 3.6636 ($R^2$ = 0.946) 이었으며, 현생 개체군은 SH = 0.8103SL + 0.5145 ($R^2$ = 0.991) 이었다. 두 개체군의 성장계수 (k) 는 차이가 없었고 (p < 0.05), 극한각장 ($SL_{\infty}$) 은 차이가 있었으나 (p > 0.05) 전체적으로 두 개체군의 상대성장식의 차이는 크지 않아 성장의 차이는 없다고 할 수 있다. 이는 두 개체군의 서식 환경이 비슷하다는 것을 의미한다. 따라서 신석기시대의 대죽리 패총이 형성될 당시 인근 연안의 해수온은 현재의 김제 연안지역과 비슷하게 높았을 가능성이 있는 것으로 추정된다.

• 자원환경지질
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• 제56권1호
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• pp.75-85
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• 2023

The potential sources and spatial distribution of heavy metals and polycyclic aromatic hydrocarbons (PAHs) were investigated in the leaf plants of Al-Zubair city. A total of 14 samples of conocarpus lancifolius plant leaf were collected and analyzed for their heavy metals and PAHs content using inductively coupled plasma mass spectrometry (ICP-MS) and a 7890 Agilent capillary gas chromatograph (GC) respectively. Bioaccumulation factor calculation revealed the highest pollution of heavy metals , due to the activity of a petrochemical in the area. The diagnostic ratio of Ant/(Phe+Ant), BaA/BaA+Chr), In/(In+BghiP), Flu/Pyr, FlA/FlA+Pyr), FlA/FlA+Pyr), ∑LMW/∑HMW are commonly used for determining the origin and source of PAHs in various environmental media. The diagnostic ratio indicated the anthropogenic origin. PAHs with five-to-six membered rings were dominant in the plant leaf, which likely results from anthropogenic activities. The leaves of C. lancifolius have a preponderance of high molecular weight PAHs compared to low molecular weight PAHs, indicating a combustion origin (car exhaust, petroleum emissions, and fossil fuel). C. lancifolius leaves are a reliable indication of atmospheric PAHs absorption. The background level of heavy metals in the city (or the near environment) is in the order of Fe > Cu > Ni > Cr. On the other hand, the bioaccumulation in plant leaves showed greater tendencies as follows: Co>Cd>Zn=As>Cu>Mn>Ni>Pb>Cr>Fe. Cobalt showed high bioaccumulation, indicating strong uptake of Co by plant leaves. These findings point to human activity and car emissions as the primary sources of roadside vegetation pollution in Al-Zubair city.