• Kyungpook Mathematical Journal
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• v.10 no.2
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• pp.105-106
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• 1970

• Tribology and Lubricants
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• v.14 no.4
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• pp.37-43
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• 1998

The friction loss between piston rings and cylinder liner is due to the tension of the piston rings. Lubricant is usually supplied to reduce the friction. However, the sliding speed of the piston varies during the reciprocating cycle and is very low near TDC(Top Dead Center)/BDC(Bottom Dead Center), where the hydrodynamic lubrication cannot be sustained. Since the lubrication regime is shifted from the hydrodynamic to the boundary lubrication near TDC/BDC, wear particles are easily generated so that the friction loss becomes bigger and bigger due to the plowing effect of wear particles. In this study, for the purpose of reducing the friction loss, an undulated surface is adopted to the cylinder liner to trap wear particles. The friction force variations, which are measured by strain gaged, show that the concept of undulated surface is one of the promising methods to effectively reduce the friction between piston rings and cylinder liner.

• Communications of the Korean Mathematical Society
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• v.25 no.1
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• pp.1-9
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• 2010

In this note, we introduce a permuting 3-derivation in nearrings and investigate the conditions for a near-ring to be a commutative ring.

• Journal of Environmental Science International
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• v.13 no.6
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• pp.543-549
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• 2004

Polycyclic aromatic hydrocarbons(PAHs) in sediments of Kwangyang bay on Korea, have been investigated by gas chromatography-mass spectrometery (GC/MS). The average content of total PAHs in all samples was 2,211ppb, and the range was from 36 to 22,699ppb. The higher concentrations were found in sediment sampled near Kwangyang iron processing plant, Taeindo. The resulting distributions of PAHs according to the number of aromatic ring and molecular ratios of specific aromatic compounds (phenanthrene, anthracene, fluoranthene and pyrene) have been discussed in terms of sample location, origin of the organic matter. Four, five and six rings of PAHs were mainly found near to Kwangyang iron processing plant, and three and four rings near to Yeosu chemical kombinat This result typically indicated the local characteristics, depending on the origin of PAHs.

• Communications of the Korean Mathematical Society
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• v.23 no.4
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• pp.469-477
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• 2008

We introduce the notion of two-sided $\Gamma$-$\alpha$-derivation of a $\Gamma$-near-ring and give some generalizations of [1, 2].

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.3
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• pp.394-398
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• 2012

Based on the theory of a bipolar fuzzy set, the notion of a bipolar fuzzy subring/ideal of a Near ring is introduced and related properties are investigated. Characterizations of a bipolar fuzzy subnear ring and a bipolar fuzzy ideal in near ring are established. Relations between a bipolar fuzzy ideal and a level cut are discussed. Using bipolar fuzzy ideals, we discuss characterizations of Noetherian Near ring.

• Kyungpook Mathematical Journal
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• v.22 no.2
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• pp.161-166
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• 1982

• Proceedings of the Korea Society of Mathematical Education Conference
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• 2010.04a
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• pp.17-20
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• 2010

• East Asian mathematical journal
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• v.14 no.1
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• pp.135-140
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• 1998

• East Asian mathematical journal
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• v.11 no.2
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• pp.133-135
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• 1995