• 한국수학교육학회지시리즈B:순수및응용수학
• /
• 제13권2호
• /
• pp.113-120
• /
• 2006

In this paper, we introduce the concept of P(r,m) $\Gamma$-near-ring and obtain some characterization of P(r,m) $\Gamma$-near-rings through regularity conditions.

• 대한수학회논문집
• /
• 제33권1호
• /
• pp.37-44
• /
• 2018

We prove some theorems showing that a right Jordan ideal or a left Jordan ideal of a 3-prime near-ring must be commutative if it admits a nonzero derivation acting as a homomorphism or an antihomomorphism. Moreover, we give examples proving necessity of the conditions given.

• East Asian mathematical journal
• /
• 제10권2호
• /
• pp.287-293
• /
• 1994

• Tribology and Lubricants
• /
• 제25권5호
• /
• pp.311-317
• /
• 2009

To satisfy the more severe emission regulation and the demand of higher fuel economy in near future, the combustion pressure and power output of engines is going to be higher. In order to get the reduction of engine emission and the higher power, it is needed the reduction of the tension and width of ring pack. The lower tension ring and the thinner width ring can bring not only the friction reduction between the ring and liner during engine running, but also the adjustment of the blow-by gas and oil consumption by changing in the pressure in the crevice volume and the axial motion of rings togethe with the adjustment of the inter-ring crevice volumes. In this study, by using a developed basic computer proglram that predicts the blow-by gas and oil consumption of engines, it is to be examined how satisfying the level of the blow-by gas and oil consumption as being installed the piston ring pack with thinner width ring and lower tension ring.

• KSTLE International Journal
• /
• 제2권1호
• /
• pp.40-45
• /
• 2001

The paper deals with a non-linear finite element analysis of the thermomechanical distortions of an elastomeric O-ring seal including a temperature gradient. Axial compression of O-ring seals, as well as the influence of the temperature gradients and various O-ring seal models, are investigated based on the axisymmetric analysis. The highest temperature occurs near the interface of the O-ring between the dovetail groove bottom and the O-ring seal. The calculated FEM results indicate that the composite O-ring with the diametral ratio, 0.8 shows very stable and recommendable compared with other seal models far elevated temperatures and corrosive environments.

• Journal of the Korean Wood Science and Technology
• /
• 제52권4호
• /
• pp.319-330
• /
• 2024

The present study aimed to investigate the death years of conifers to verify the time difference between landslide occurrence in 2011 and tree mortality near Chibanmok and Jangteomok shelters in the Jirisan National Park. Furthermore, abrupt growth reduction was also investigated to verify the living conditions when they were living. For the study, tree-ring analysis was conducted by selecting 14 living Abies koreana near the landslide area and 7 dead ones in the landslide area in the Chibanmok site, and 13 living conifers (7 Picea jezoensis, 5 A. koreana, and 1 Pinus koraiensis) near landslide area and 4 dead ones (2 P. jezoensis and 2 A. koreana) in landslide area in the Jangteomok site. Using the tree-ring samples from living A. koreana 137-year long chronology (1885-2021) was established for the Chibanmok site and 364- and 65-year long P. jezoensis (1658-2021) and A. koreana (1957-2021) chronologies was built for the Jangteomok site. Through the synchronization test between the tree-ring time series from dead conifers and the corresponding chronologies, it was verified that the death of conifers in the landslide areas occurred after 2011, when the landslide happened, except for only one tree. It was further verified through the abrupt growth reduction test that the growth condition of dead conifers before the landslide in 2011 was satisfactory.

• Kyungpook Mathematical Journal
• /
• 제43권4호
• /
• pp.587-592
• /
• 2003

A near-ring N is called strongly reduced if, for $a{\in}N$, $a^2{\in}N_c$ implies $a{\in}N_c$, where $N_c$ denotes the constant part of N. We investigate some properties of strongly reduced near-rings and apply those to the study of left strongly regular near-rings. Finally we classify all reduced, and strongly reduced near-rings of order ${\leq}7$.

• 대한수학회보
• /
• 제45권2호
• /
• pp.263-267
• /
• 2008

Kaplansky introduced the Baer rings as rings in which every left (or right) annihilator of each subset is generated by an idempotent. On the other hand, Hattori introduced the left (resp. right) P.P. rings as rings in which every principal left (resp. right) ideal is projective. The purpose of this paper is to introduce the near-rings with Baer like condition and near-rings with P.P. like condition which are somewhat different from ring case, and to extend the results of Arendariz and Jondrup.

• Journal of applied mathematics & informatics
• /
• 제33권3_4호
• /
• pp.469-474
• /
• 2015

In this paper, we will consider the notions of (m, n)-potent conditions in near-rings, in particular, a near-ring R with left bipotent or right bipotent condition. We will derive some properties of near-rings with (1, n) and (n, 1)-potent conditions where n is a positive integer, and then some properties of near-rings with (m, n)-potent conditions. Also, we may discuss the behavior of R-subgroups in (1, n)-potent or (n, 1)-potent near-rings..

• Journal of applied mathematics & informatics
• /
• 제29권3_4호
• /
• pp.1007-1010
• /
• 2011

In this paper, we begin with some basic concepts of substructures of near-rings, and then using some right substructures of near-rings, we may define the right semidirect sum of near-rings. Next, we investigate that every near-ring can be decomposed with right semidirect sum of right ideal by right R-subgroup, and then give some examples.