• 대한수학회보
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• 제56권3호
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• pp.729-743
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• 2019

In this paper, we introduce strongly quasi primary ideals which is an intermediate class of primary ideals and quasi primary ideals. Let R be a commutative ring with nonzero identity and Q a proper ideal of R. Then Q is called strongly quasi primary if $ab{\in}Q$ for $a,b{\in}R$ implies either $a^2{\in}Q$ or $b^n{\in}Q$ ($a^n{\in}Q$ or $b^2{\in}Q$) for some $n{\in}{\mathbb{N}}$. We give many properties of strongly quasi primary ideals and investigate the relations between strongly quasi primary ideals and other classical ideals such as primary, 2-prime and quasi primary ideals. Among other results, we give a characterization of divided rings in terms of strongly quasi primary ideals. Also, we construct a subgraph of ideal based zero divisor graph ${\Gamma}_I(R)$ and denote it by ${\Gamma}^*_I(R)$, where I is an ideal of R. We investigate the relations between ${\Gamma}^*_I(R)$ and ${\Gamma}_I(R)$. Further, we use strongly quasi primary ideals and ${\Gamma}^*_I(R)$ to characterize von Neumann regular rings.

• Kyungpook Mathematical Journal
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• 제57권2호
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• pp.193-198
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• 2017

In this paper we investigate 2-absorbing ${\delta}$-primary ideals which unify 2-absorbing ideals and 2-absorbing primary ideals. A number of results about 2-absorbing ideals and 2-absorbing primary ideals are extended into this general framework.

• 대한수학회지
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• 제52권1호
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• pp.97-111
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• 2015

Let R be a commutative ring with $1{\neq}0$. In this paper, we introduce the concept of weakly 2-absorbing primary ideal which is a generalization of weakly 2-absorbing ideal. A proper ideal I of R is called a weakly 2-absorbing primary ideal of R if whenever a, b, $c{\in}R$ and $0{\neq}abc{\in}I$, then $ab{\in}I$ or $ac{\in}\sqrt{I}$ or $bc{\in}\sqrt{I}$. A number of results concerning weakly 2-absorbing primary ideals and examples of weakly 2-absorbing primary ideals are given.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권3호
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• pp.273-288
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• 2010

In this paper, we propose a cooperative multi-relay scheme for a secondary system to achieve spectrum access along with a primary system. In the primary network, a primary transmitter (PT) transmits the primary signal to a primary receiver (PR). In the secondary network, N secondary transmitter-receiver pairs (ST-SR) selected by a centralized control unit (CCU) are ready to assist the primary network. In particular, in the first time slot, PT broadcasts the primary signal to PR, which is also received by STs and SRs. At STs, the primary signal is regenerated and linearly combined with the secondary signal by assigning fractions of the available power to the primary and secondary signals respectively. The combined signal is then broadcasted by STs in a predetermined order. In order to achieve diversity gain, STs, SRs and PT will combine received replicas of the primary signal, using selection combining technique (SC). We derive the exact outage probability for the primary network as well as the secondary network. The simulation results are presented to verify the theoretical analyses.

• Kyungpook Mathematical Journal
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• 제56권1호
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• pp.107-120
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• 2016

Let R be a commutative semiring. The purpose of this note is to investigate the concept of 2-absorbing (resp., weakly 2-absorbing) primary ideals generalizing of 2-absorbing (resp., weakly 2-absorbing) ideals of semirings. A proper ideal I of R said to be a 2-absorbing (resp., weakly 2-absorbing) primary ideal if whenever $a,b,c{\in}R$ such that $abc{\in}I$ (resp., $0{\neq}abc{\in}I$), then either $ab{\in}I$ or $bc{\in}\sqrt{I}$ or $ac{\in}\sqrt{I}$. Moreover, when I is a Q-ideal and P is a k-ideal of R/I with $I{\subseteq}P$, it is shown that if P is a 2-absorbing (resp., weakly 2-absorbing) primary ideal of R, then P/I is a 2-absorbing (resp., weakly 2-absorbing) primary ideal of R/I and it is also proved that if I and P/I are weakly 2-absorbing primary ideals, then P is a weakly 2-absorbing primary ideal of R.

• The Korean Journal of Physiology and Pharmacology
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• 제25권6호
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• pp.593-601
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• 2021

Primary cilia on kidney tubular cells play crucial roles in maintaining structure and physiological function. Emerging evidence indicates that the absence of primary cilia, and their length, are associated with kidney diseases. The length of primary cilia in kidney tubular epithelial cells depends, at least in part, on oxidative stress and extracellular signal-regulated kinase 1/2 (ERK) activation. Hydrogen sulfide (H₂S) is involved in antioxidant systems and the ERK signaling pathway. Therefore, in this study, we investigated the role of H₂S in primary cilia elongation and the downstream pathway. In cultured Madin-Darby Canine Kidney cells, the length of primary cilia gradually increased up to 4 days after the cells were grown to confluent monolayers. In addition, the expression of H₂S-producing enzyme increased concomitantly with primary cilia length. Treatment with NaHS, an exogenous H₂S donor, accelerated the elongation of primary cilia whereas DL-propargylglycine (a cystathionine γ-lyase inhibitor) and hydroxylamine (a cystathionine-β-synthase inhibitor) delayed their elongation. NaHS treatment increased ERK activation and Sec10 and Arl13b protein expression, both of which are involved in cilia formation and elongation. Treatment with U0126, an ERK inhibitor, delayed elongation of primary cilia and blocked the effect of NaHS-mediated primary cilia elongation and Sec10 and Arl13b upregulation. Finally, we also found that H₂S accelerated primary cilia elongation after ischemic kidney injury. These results indicate that H₂S lengthens primary cilia through ERK activation and a consequent increase in Sec10 and Arl13b expression, suggesting that H₂S and its downstream targets could be novel molecular targets for regulating primary cilia.

• Nuclear Engineering and Technology
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• 제52권10호
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• pp.2204-2220
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• 2020

An open-pool type research reactor is designed and operated considering the accessibility around the pool top area to enhance the reactor utilization. The reactor structure assembly is placed at the bottom of the pool and filled with water as a primary coolant for the core cooling and radiation shielding. Most radioactive materials are generated from the fuel assemblies in the reactor core and circulated with the primary coolant. If the primary coolant goes up to the pool surface, the radiation level increases around the working area near the top of the pool. Hence, the hot water layer is designed and formed at the upper part of the pool to suppress the rising of the primary coolant to the pool surface. The temperature gradient is established from the hot water layer to the primary coolant. As this temperature gradient suppresses the circulation of the primary coolant at the upper region of the pool, the radioactive primary coolant rising up directly to the pool surface is minimized. Water mixing between these layers is reduced because the hot water layer is formed above the primary coolant with a higher temperature. The radiation level above the pool surface area is maintained as low as reasonably achievable since the radioactive materials in the primary coolant are trapped under the hot water layer. The key to maintaining the stable hot water layer and keeping the radiation level low on the pool surface is to have a stable flow of the primary coolant. In the research reactor with a downward core flow, the primary coolant is dumped into the reactor pool and goes to the reactor core through the flow guide structure. Flow fields of the primary coolant at the lower region of the reactor pool are largely affected by the dumped primary coolant. Simple, circular, and duct type discharge headers are designed to control the flow fields and make the primary coolant flow stable in the reactor pool. In this research, flow fields of the primary coolant and hot water layer are numerically simulated in the reactor pool. The heat transfer rate, temperature, and velocity fields are taken into consideration to determine the formation of the stable hot water layer and primary coolant flow. The bulk Richardson number is used to evaluate the stability of the flow field. A duct type discharge header is finally chosen to dump the primary coolant into the reactor pool. The bulk Richardson number should be higher than 2.7 and the temperature of the hot water layer should be 1 ℃ higher than the temperature of the primary coolant to maintain the stability of the stratified thermal layer.

• 한국수학교육학회지시리즈C:초등수학교육
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• 제3권1호
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• pp.47-54
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• 1999

The development of computer software accelerates the change of teaching-learning method in primary school mathematics. In this paper, we discuss how to apply the software GSP to teach mathematics in primary school and suggest some examples fur the creative and active loaming. Moreover, we give the efficient teaching method for the primary school mathematics.

• Journal of Gastric Cancer
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• 제11권3호
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• pp.167-172
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• 2011

Purpose: Peritoneal seeding of gastric cancer is known to have a poor prognosis. With the diagnosis of peritoneal seeding, there is no effective treatment modality. Gastrectomy with chemotherapy or primary chemotherapy is basically one of major options for this condition. This study was conducted to compare the clinical outcomes of these treatments and to identify the better way to improve the prognosis of patients with peritoneal seeding. Materials and Methods: Between 2001 and 2007, gastric cancer patients with peritoneal seeding by preoperative or intraoperative diagnosis were reviewed retrospectively. The enrolled patients were divided as primary gastrectomy and primary chemotherapy group. Clinicopathologic characteristics and clinical outcomes of groups were analyzed and compared. Results: Fifty-four patients were enrolled. 21 patients belonged to the group of primary gastrectomy and 33 patients were to the primary chemotherapy group. Among 33 patients of the primary chemotherapy group, 17 patients were received only chemotherapy and 16 patients were received gastrectomy due to the good responses of primary chemotherapy. The 3 years survival rates were 14% in primary gastrectomy group, 55% in patients who received gastrectomy after primary chemotherapy, and 0% in patients with primary chemotherapy only. Conclusions: Although this study had many limitations, some valuable information was produced. In terms of survival benefits for the gastric cancer patients with peritoneal seeding, primary gastrectomy and additional gastrectomy after primary chemotherapy revealed the better clinical outcomes. But, prospective randomized clinical study and multi-center study should be performed to decide proper treatment for gastric cancer patients with peritoneal seeding.

• 아동학회지
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• 제3권
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• pp.97-113
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• 1982

Problems This study was aimed to find out the effects of Kindergarten education on primary school child's learning achievement and it's continuance. The specific question to be investigated in this study can he summarized as follows. 1. How did the kindergarten education effect upon primary school child's learning achievement and behavioral development? 2. How did the differences of learning achievement and behavioral development between groups of children attending kindergarten and not attending kindergarten? Methods 1. Subjects One hundred and twenty children of sixth grade and one hundred primary school's teachers were employed 1) Sixty of children were experimented groups who had received kindergarten education. Sixty of Children are Control group who had not received Kindergarten education. The subjects were sampled in N primary school in seoul and Y primary school in Taejeon. Sixty of children were boys and sixty of children were girls. 2) Fifty of teachers were sampled in N primary school in Seoul and Fifty of teachers were sampled in Y primary school in Taejeon. 2. Instrument 1) School cumulative record. School cumulative record was referred to find out the differences of school records on learning achievement in morality, National language, social studies, arithmatics, natural science, gymnastics, music, fine arts and behavioral development in industry, responsibility, coorperation, indeperdence, law abiding spirit between experimental group and control group. 2) Questionnaire paper which constructed 10 articles. Questionnaire paper asked to primary school teachers for effects of kindergarten education. Results The results of date analysis can summarized as follows. 1. Kindergarten education, generally, is regarded effective at least for school work achievement but not so effective for morality and physical education. 2. Kindergarten education is not so effective in all school works of primary school in its continuance since its effectiveness begins to fade away from the 4th grade of primary school. But such continuance tends to be outstanding especially in national language, social subjects and arts. 3. The experiences of kindergarten education is not much helpful to behavioral development during primary school. 4. Primary school teachers recognize that kindergarten education contributes to curriculum work and behavioral development for primary school children.