• Kyungpook Mathematical Journal
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• v.46 no.4
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• pp.603-613
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• 2006

Near-rings considered are right near-rings and R is a near-ring. $J_0^r(R)$, the right Jacobson radical of R of type-0, was introduced and studied by the present authors. In this paper $J_1^r(R)$ and $J_2^r(R)$, the right Jacobson radicals of R of type-1 and type-2 are introduced. It is proved that both $J_1^r$ and $J_2^r$ are radicals for near-rings and $J_0^r(R){\subseteq}J_1^r(R){\subseteq}J_2^r(R)$. Unlike the left Jacobson radical classes, the right Jacobson radical class of type-2 contains $M_0(G)$ for many of the finite groups G. Depending on the structure of G, $M_0(G)$ belongs to different right Jacobson radical classes of near-rings. Also unlike left Jacobson-type radicals, the constant part of R is contained in every right 1-modular (2-modular) right ideal of R. For any family of near-rings $R_i$, $i{\in}I$, $J_{\nu}^r({\oplus}_{i{\in}I}R_i)={\oplus}_{i{\in}I}J_{\nu}^r(R_i)$, ${\nu}{\in}\{1,2\}$. Moreover, under certain conditions, for an invariant subnear-ring S of a d.g. near-ring R it is shown that $J_2^r(S)=S{\cap}J_2^r(R)$.

• Journal of Oral Medicine and Pain
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• v.44 no.1
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• pp.25-30
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• 2019

Purpose: The exact causes of burning mouth syndrome (BMS) is unclear so far. There are many studies to elucidate the relation between oral disease and genetic predisposition. In this study, we first tried to investigate salivary exosomal genetic components that could play an important role for diagnosing and elucidating the progression of BMS. Methods: We compared salivary exosomal micro RNAs (miRNAs) of BMS Patients to those of control using next generation sequencing (NGS). Unstimulated whole saliva from 15 patients with BMS and 10 control subjects were divided into two sets. Isolated exosomes and their total RNAs were subject to NGS for the screening of miRNAs. Results: There were up-regulated 10 exosomal miRNAs (hsa-miR-1273h-5p, hsa-miR-1273a, hsa-miR-1304-3p, hsa-miR-4449, hsa-miR-1285-3p, hsa-miR-6802-5p, hsa-miR-1268a, hsa-miR-1273d, hsa-miR-1273f, and hsa-miR-423-5p) and down-regulated 18 exosomal miRNAs (hsa-miR-27b-3p, hsa-miR-16-5p, hsa-miR-186-5p, hsa-miR-142-3p, hsa-miR-141-3p, hsa-miR-150-5p, hsa-miR-374a-5p, hsa-miR-93-5p, hsa-miR-29c-3p, hsa-miR-29a-3p, hsa-miR-148a-3p, hsa-miR-22-3p, hsa-miR-27a-3p, hsa-miR-424-5p, hsa-miR-19b-3p, hsa-miR-99a-5p, hsa-miR-548d-3p, and hsa-miR-19a-3p) in BMS patients comparing with those of control subjects. Conclusions: We show that there are 28 differential expression of miRNAs between the patients with BMS and those of control subjects. The specific function of indicated miRNAs should be further elucidated.

• Bulletin of the Korean Mathematical Society
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• v.57 no.4
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• pp.1075-1081
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• 2020

Let R be a domain. It is proved that R is coherent when IFD(R) ⩽ 1, and R is Noetherian when IPD(R) ⩽ 1. Consequently, R is a G-Prüfer domain if and only if IFD(R) ⩽ 1, if and only if wG-gldim(R) ⩽ 1; and R is a G-Dedekind domain if and only if IPD(R) ⩽ 1.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.3
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• pp.421-424
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• 2009

In this paper, we introduce the concept of fuzzy semi-weakly r-semicontinuous mappings on a fuzzy topological space and study characterizations for such mappings. And we investigate the relationships among fuzzy r-semicontinuity, fuzzy semi-weakly r-semicontinuity and fuzzy weakly r-semicontinuity.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.569-573
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• 2010

We introduce the concept of fuzzy r-minimal preopen set on a fuzzy minimal space. We also introduce the concept of fuzzy r-M precontinuous mapping which is a generalization of fuzzy r-M continuous mapping, and investigate characterization of fuzzy r-M precontinuity.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.2
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• pp.129-146
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• 2008

The aim of this study was to compare and analyze wear resistance of acrylic resin tooth in denture opposing to different types of restoration materials. Also, it aimed to compare and analyze the hardness of three various types of resin artificial teeth when using five different types of denture detergents. In this study three types of artificial teeth were used. As ordinary acrylic resin tooth $Trubyte^{(R)}Biotone^{(R)}$ (Dentsply, U.S.A.) was used, and as high hardness resin tooth Endura $Posterio^{(R)}$ (Shofu, Japan) and Physio $Duracross^{(R)}$ (Nissin, Japan) were used. To compare wear resistance, gold alloy, dental porcelain, and composite resin were used as opposing restorations. In addition, with three types of resin tooth stated above, five types of denture detergents, which are $Yuhanrox^{(R)}$ (Yuhanclorox, Korea), $Polident^{(R)}$ (Yuhan Co., Korea), $Cidex^{(R)}OPA$ (Johnson & Johnson Medical Co., Korea), $Hexamedin^{(R)}$ (Bukwang Pharm Co., Korea) and Daihan sterile $water^{(R)}$ (Daihan Pharm Co., Korea) were used to compare and analyze the effects denture detergents have on the surface hardness. The results of this study were as follow : 1. When composite resin and dental porcelain were used as the opposing restorations, $Trubyte^{(R)}$ $Biotone^{(R)}$, Endura $Posterio^{(R)}$, Physio $Duracross^{(R)}$ in ascending order showed decrease of cusp height with significant difference (p<0.05). 2. When gold alloy was used as opposing restoration, there was decrease in the cusp height in order of $Trubyte^{(R)}Biotone^{(R)}$, Endura $Posterio^{(R)}$, Physio $Duracross^{(R)}$ and $Trubyte^{(R)}$ $Biotone^{(R)}$ especially showed significant decrease in high cusp height as compared to two other types of artificial tooth (p<0.05). 3. When composite resin, gold alloy and dental porcelain were used as opposing restorations, $Trubyte^{(R)}$ $Biotone^{(R)}$, Endura $Posterio^{(R)}$, Physio $Duracross^{(R)}$ in order decreased greatly in weight and these three materials showed significant difference (p<0.05). 4. Comparing the experiment values, decrease in strength had significant difference in all resin artificial teeth before and after the denture detergents were used (p<0.05). 5. When resin artificial teeth were subsided in $Yuhanrox^{(R)}$, $Cidex^{(R)}OPA$, and $Hexamedin^{(R)}$, $Trubyte^{(R)}$ $Biotone^{(R)}$, Endura $Posterio^{(R)}$, Physio $Duracross^{(R)}$ in order showed decrease in hardness, and $Trubyte^{(R)}$ $Biotone^{(R)}$ especially showed significant high decrease hardness as to other two types of artificial teeth (p<0.05). Therefore, Physio $Duracross^{(R)}$ seems to have superior wear resistance, and together with Endura $Posterio^{(R)}$, it presents excellent hardness as compared to $Trubyte^{(R)}$ $Biotone^{(R)}$. However, since this study is fragmentary, it should be given careful consideration and more study need to be done before making a definitive conclusion.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.4 no.2
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• pp.123-136
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• 1992

A preliminary thermodynamic design model of two-evaporator refrigerator/freezer system is constructed. This system is based on Lorentz-Meutzner cycle using refrigerant mixtures. This model screens alternative refrigerant (R32, R125, R143a, R22, R134a, R152a, R124, R142b, R123) mixtures to select the best performance-giving refrigerant mixtures and its composition for the system. Also, it estimates the effects of cooling temperatures of intercoolers, evaporator's area ratio, cooling load ratio on the performance of the system. The COP of the system ranges from 1.4 to 1.6, which is superior to that of the single evaporator system charged with R12 by 13% to 29%. Among 15 mixtures, R22/R123, R143a/R123, R32/R142b, and R32/R124 (in the order of high COP) are most recommendable. For the case of R22/R123, R22 mass fraction more than 0.5(Load Ratio=1.0) or 0.7(Load Ratio=0.33) is recomended in order to replace R12 without reduction in volumetric capacity when keeping the compressor as the same one. COP has the highest value with X(R22)=0.7 and 0.8, respectively. For the case of R143a/R123, in the similar manner, mass fraction of R143a is more than 0.5 or 0.6 while best performance occurs at X(R143a)=0.8. Higher temperature intercooler is more important for the performance of the system than lower temperature intercooler. The area ratio of evaporators is roughly proportional to load ratio of the evaporators.

• Korean small business review
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• v.43 no.3
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• pp.21-42
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• 2021

Since R&D (Research and Development) of small companies is becoming more and more important, and government R&D grants are still increasing. This study aims to investigate the factors influencing R&D performance of small companies and necessary capabilities of them. Based on empirical study of 3,636 small companies which participated and completed government R&D grant project, technology innovation capability and technology commercializing capability of small companies are positively related with organizational competences, with moderating effects of entrepreneurship. In addition, their R&D capabilities are not significantly related with R&D commercializing performance directly, but mediated with organizational competences. The results of study suggest implications of measuring the R&D performance of small companies and government support policy with the importance of organizational competences as an intermediate variable of R&D performances.

• Economic and Environmental Geology
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• v.45 no.5
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• pp.579-587
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• 2012

The purpose of this study is to emphasize the necessity of extention of a government R&D planning scope. Presently, government R&D planning is focused on the selecting a R&D project. There is no R&D strategy for R&D conducting such as the composition of R&D team, collaboration and knowledge flow. Ordinarily these strategies are established by research director. This study analyzed the determinants of excellent R&D performance and proposed R&D strategy for R&D conducting using the patent bibliograpy information in energy resources production technology field. On the other hand, this study introduced the concept of technology lifecycle and showed that R&D strategy should be differentiated by technology lifecycle.

• Communications of the Korean Mathematical Society
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• v.22 no.1
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• pp.41-51
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• 2007

Let R be a ring with left identity e and suitably-restricted additive torsion, and Z(R) its center. Let H : $R{\times}R{\times}R{\rightarrow}R$ be a symmetric 3-additive mapping, and let h be the trace of H. In this paper we show that (i) if for each $x{\in}R$, $$n=<<\cdots,\;x>,\;\cdots,x>{\in}Z(R)$$ with $n\geq1$ fixed, then h is commuting on R. Moreover, h is of the form $$h(x)=\lambda_0x^3+\lambda_1(x)x^2+\lambda_2(x)x+\lambda_3(x)\;for\;all\;x{\in}R$$, where $\lambda_0\;{\in}\;Z(R)$, $\lambda_1\;:\;R{\rightarrow}R$ is an additive commuting mapping, $\lambda_2\;:\;R{\rightarrow}R$ is the commuting trace of a bi-additive mapping and the mapping $\lambda_3\;:\;R{\rightarrow}Z(R)$ is the trace of a symmetric 3-additive mapping; (ii) for each $x{\in}R$, either $n=0\;or\;<n,\;x^m>=0$ with $n\geq0,\;m\geq1$ fixed, then h = 0 on R, where denotes the product yx+xy and Z(R) is the center of R. We also present the conditions which implies commutativity in rings with identity as motivated by the above result.