• Korean Journal of Mathematics
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• v.22 no.2
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• pp.217-234
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• 2014

Mason extended the reflexive property for subgroups to right ideals, and examined various connections between these and related concepts. A ring was usually called reflexive if the zero ideal satisfies the reflexive property. We here study this property skewed by ring endomorphisms, introducing the concept of an ${\alpha}$-skew reflexive ring, where is an endomorphism of a given ring.

• Communications of the Korean Mathematical Society
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• v.33 no.2
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• pp.371-378
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• 2018

This article concerns a ring property which is seated between IFP and IPFP rings. We study the insertion property of nonzero powers at zero products, introducing the concept of strongly IPFP ring. The structure of strongly IPFP rings is investigated in relation with nearly seated ring properties and ring extensions.

• Bulletin of the Korean Mathematical Society
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• v.38 no.3
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• pp.543-549
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• 2001

We show that R[X] is a Krull (Resp. factorial) ring if and only if R is a normal Krull (resp, factorial) ring with a finite number of minimal prime ideals if and only if R is a Krull (resp. factorial) ring with a finite number of minimal prime ideals and R(sub)M is an integral domain for every maximal ideal M of R. As a corollary, we have that if R[X] is a Krull (resp. factorial) ring and if D is a Krull (resp. factorial) overring of R, then D[X] is a Krull (resp. factorial) ring.

• Bulletin of the Korean Mathematical Society
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• v.54 no.4
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• pp.1123-1139
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• 2017

The aim in this note is to describe some classes of rings in relation to factorization by prime radical, upper nilradical, and Jacobson radical. We introduce the concepts of tpr ring, tunr ring, and tjr ring in the process, respectively. Their ring theoretical structures are investigated in relation to various sorts of factor rings and extensions. We also study the structure of noncommutative tpr (tunr, tjr) rings of minimal order, which can be a base of constructing examples of various ring structures. Various sorts of structures of known examples are studied in relation with the topics of this note.

• Kyungpook Mathematical Journal
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• v.61 no.3
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• pp.487-494
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• 2021

In this paper, we study rings with Noetherian spectrum, rings with locally Noetherian spectrum and rings with t-locally Noetherian spectrum in terms of the polynomial ring, the Serre's conjecture ring, the Nagata ring and the t-Nagata ring. In fact, we show that a commutative ring R with identity has Noetherian spectrum if and only if the Serre's conjecture ring R[X]_U has Noetherian spectrum, if and only if the Nagata ring R[X]_N has Noetherian spectrum. We also prove that an integral domain D has locally Noetherian spectrum if and only if the Nagata ring D[X]_N has locally Noetherian spectrum. Finally, we show that an integral domain D has t-locally Noetherian spectrum if and only if the polynomial ring D[X] has t-locally Noetherian spectrum, if and only if the t-Nagata ring $D[X]_{N_v}$ has (t-)locally Noetherian spectrum.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.143-150
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• 2007

Ring and cylinder bore wear may not be a problem in most current automotive engines. However, a small change in ring face and cylinder bore diameter can significantly affect the lubrication characteristics and ring axial motion. This in turn can cause to change inter-ring pressure, blow-by and oil consumption in an engine. Therefore, by predicting the wear of piston ring face and cylinder bore altogether, the changed ring end gap and the changed volume of gas reservoir can be calculated. Then the excessive oil consumption can be predicted. Here, the oil amount through top ring gap into combustion chamber is estimated as engine oil consumption. Furthermore, the wear theories of ring and cylinder bore are included. The changed oil consumption caused by the new end gap and the new volume of oil reservoir around second land, can be calculated at some engine running interval. Meanwhile, the wear amount and oil consumption occurred during engine durability cycle are compared with the calculated values. The wear data of rings and cylinder bore are obtained from three engines after engine durability test. The calculated wear data of each part are turn out to be around the band of averaged test values or a little below. It is shown that the important factor regarding oil consumption increasement is the wear of ring face.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.6
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• pp.238-249
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• 1995

The gas pressure acting on the rings in internal combustion engine influences the friction and wear characteristics. Inter-ring pressure variation during engine operation results from cylinder gas flow through a piston-ring pack. The flow passages consist of ring end gaps and clearances between the ring and the piston groove. The gas flow in the clearance between the ring and the groove is directly affected by the axial motion of the ring in the groove. In this paper the asperity contact force is newly considered in the prediction of the clearence between the ring and the groove surface. This term must be taken into account physically in case that the clearance get narrow rather than asperity height between the ring and the groove surface. Finally, comparisons of calculated inter-ring gas pressures based on the analytical method are made with the measured ones. The agereement was found to be good below midium engine speed, 3000rpm. In order to obtain accurate analytical results to the extend of high rpm range, it is recommended to include oil ring motion as well as top and second ring in analytical model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.44-50
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• 2019

CMP is the most critical process in the manufacture of silicon wafers, and the use of retaining rings, which are consumable parts used in CMP equipment, is increasingly important. Since the retaining ring is made of plastic, it is not only weak in strength but also has the problem of taking a long time for the flattening operation of the ring itself performed before the CMP process, and of the imbalance of force due to bolt tightening causing uneven wear. In order to solve this problem, the retaining ring and the insert ring are integrally used, and the flatness of the retaining ring may be affected depending on the material of the insert ring. Also, the residual stress generated in the manufacturing process of the insert ring may cause distortion of the ring, which may adversely affect the precision polishing. In this study, when the insert ring is made of Zn or STS304, the thickness variation and the flatness of the retaining ring are compared and, finally, the material removal rate is analyzed by polishing the wafer by the oxide CMP process. Through these experiments, the effects of the insert ring material on the polishing accuracy of the wafers were investigated.

• Journal of the Korean Mathematical Society
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• v.55 no.5
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• pp.1193-1205
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• 2018

We focus our attention on a ring property that nilpotents are contained in the Jacobson radical. This property is satisfied by NI and left (right) quasi-duo rings. A ring is said to be NJ if it satisfies such property. We prove the following: (i) $K{\ddot{o}}the^{\prime}s$ conjecture holds if and only if the polynomial ring over an NI ring is NJ; (ii) If R is an NJ ring, then R is exchange if and only if it is clean; and (iii) A ring R is NJ if and only if so is every (one-sided) corner ring of R.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.212-214
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• 2004

Hardware implemented ring buffer systems and methods are presented for the effective management of the ring buffer in TCP/IP communication. The layer interface of the ring buffer systems transfer free buffer and used buffer size information to the TCP/IP stack upper or low layer. The pointer updation interface calculates a temporary pointer from the data size which is needed by the present pointer of the ring buffer and upper or lowyer layer. The pointer manager of the ring buffer systems is responsible for saving the present pointer of the ring buffer, updating the ring buffer pointer to the new pointer, calculating the free buffer size and used buffer size of the ring buffer, and transferring the information to the upper layer. The ring buffer systems help the TCP/IP layer and TCP/IP upper or lower layer to decide the sending or receiving data size effectively. The delay of transferring data can be lowered by the ring buffer system.