• Kyungpook Mathematical Journal
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• v.55 no.1
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• pp.21-28
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• 2015

Let R be a prime ring with center Z, I a nonzero ideal of R, and ${\sigma}$ a non-trivial automorphism of R such that $\{(x{\circ}y)^{\sigma}-(x{\circ}y)\}^n{\in}Z$ for all $x,y{\in}I$. If either char(R) > n or char (R) = 0, then R satisfies $s_4$, the standard identity in 4 variables.

• Journal of the Korean Data and Information Science Society
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• v.10 no.1
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• pp.11-18
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• 1999

To estimate the mean and the variance of a lognormal distribution, Finney (1941) derived the uniformly minimun variance unbiased estimators(UMVUE) in the form of infinite series. However, the conditions ${\sigma}^{2}\;>\;n\;and\;{\sigma}^{2}\;<\;\frac{n}{4}$ for computing $E(\hat{\theta}_{AM})\;and\;E(\hat{\eta}^{2}_{AM})$ are necessary. In this paper, we give an alternative derivation of the UMVUE's.

• Honam Mathematical Journal
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• v.40 no.4
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• pp.733-748
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• 2018

In this paper, we investigate a new subclass $S^{{\varphi},{\lambda}}_{{\Sigma}_m}$ of ${\Sigma}_m$ consisting of analytic and m-fold symmetric bi-univalent functions satisfying subordination in the open unit disk U. We consider the Fekete-$Szeg{\ddot{o}}$ inequalities for this class. Also, we establish estimates for the coefficients for this subclass and several related classes are also considered and connections to earlier known results are made.

• Honam Mathematical Journal
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• v.46 no.1
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• pp.1-11
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• 2024

In this paper, we introduce the notion of 𝜎-Jordan amenability of Banach algebras and some hereditary are investigated. Similar to Johnson's classic result, we give the notions of 𝜎-Jordan approximate and 𝜎-Jordan virtual diagonals, and find some relations between the existence of them and 𝜎-Jordan amenability.

• Korean Journal of Acupuncture
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• v.41 no.2
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• pp.33-42
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• 2024

Objectives : The sigma-1 receptor is implicated in stress, depression, psychostimulant sensitization, and addiction vulnerability. Prior studies have indicated that ethanol exposure modulates sigma-1 receptor activity within the Ventral Tegmental Area (VTA). Here, we explore the sub-mechanisms underlying sigma-1 receptor activity induced by HT7 (Shinmun) stimulation in behavioral alterations following acute ethanol (ETOH) administration. Methods : Male Wistar rats were investigated for pro- and anti-inflammatory markers after injection of ETOH (1 g/kg) using cytokine enzyme-linked immunosorbent assay (ELISA)s. After confirming that HT7 stimulation changed the total distance traveled in the open field test (OFT), protein changes in the Ventral tegmental area (VTA) were measured by Western blotting. The expression level of inducible nitric oxide synthase (iNOS) after administration of a sigma-1 receptor antagonist (dihydrobromide 1047; BD1047, 10 mg/kg i.p.) and Shenmen (HT7) stimulation was compared. Results : As a result, acute ETOH administration increased proinflammatory marker levels (TNF-𝛼 and IL-6). HT7 stimulation restored the total distance response after acute ethanol administration. In addition, in the VTA, the levels of a microglial marker (iNOS), sigma-1 receptor and protein kinase C, which are predicted to be involved in up- and downregulation, were restored by HT7 stimulation. In particular, HT7 stimulation modulates iNOS expression through effects similar to BD treatment. This study suggests that the stimulatory effect of HT7 may be driven by microglial activation. Conclusions : Microglial activity is regulated by sigma-1 receptor, and sigma-1 receptor activity is regulated by HT7 stimulation. Significantly, we demonstrate that HT7 stimulation ameliorates behavioral alterations induced by acute ETOH administration through microglial activation within the VTA.

• The Journal of Engineering Geology
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• v.6 no.2
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• pp.103-110
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• 1996

This study shows the variation of poisson's ratio according to stress for the Cretaceous sandstones and shale in the Euiseoung Subbasin. To make a mechanical experiment, samples prepared with 3.0 cm in diameter and 6.2 cm in length were used in testing stress and strain. Generally poisson's ratio has been considered as one of properties, but contrary to steel, the test result makes sure that poisson's ratio has functional relation to stress. I had used four methods to calculate poisson's ratio, Poisson's ratio shows considerable different results according to the calculating, method but it has similar tendency in an elastic limit. Poisson' s ratio increases rapidly and is distinguished clearly in internal fracture region according to the calculating method. Poisson's ratio of sandstone and shale is different from one another in low and high stress regimes,but it is linearly proportional to the stress in an elastic regimes, that is, ${\nu}_t={\;}{\nu}_0+P_{\sigma}({\nu}_0$:first stage Poisson's ratio, ${\nu}_t$:poisson's ratio, P: poisson's coefficient, $\sigma$:stress). Poisson's ratios of two kinds of rock samples show continuous variation from 0.1 to 0.21 in an elastic regime. The variation of poisson's ratio is much wider in an internal fracture regine. It varies from 0.22 to 0.45 in sandstone, which is out of elastic regime.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.111-119
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• 1993

In this study, the transient impact structural stress analysis of tracked vehicle structures under recoil impact load is investigated. ANSYS, ABAQUS Code are used for modelling and analytical procedures. The highest maximum Tresca stress occurs on race ring portion and its stress level is (.sigma.$_{T}$)$_{max}$ =20-40kgf/m $m^{2}$. The second highest stress occurs on upper plate of chassis and down plate of turret. The maximum stress level increases with loading direction and elevation angle. The results from liner static load analysis are very much different with impact analysis. Therefore, the practical solutions of structures under impact load can be obtained by only nonlinear transient impact analysis. The impact stress analysis of the steel vehicle structures is conducted. The maximum stress level is less than (.sigma.$_T/)$_{max}$m $m^{2}$. So, the design concept of steel structures can be adapted for new alternatives.s.s.s..s.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.3
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• pp.216-221
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• 2014

In this paper, we introduce the concept of generalized double fuzzy semi-basically disconnected space and related notions such as (r, s)-generalized fuzzy semiopen-$F_{\sigma}$ sets, (r, s)-generalized fuzzy semiclosed-$G_{\delta}$ sets, generalized double fuzzy $semi^*$-open function, generalized double fuzzy $semi^*$-continuous function and generalized double fuzzy $semi^*$-irresolute function. Some interesting properties and characterizations of the concepts introduced are studied.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.2
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• pp.1-8
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• 1991

The spheroidization of cold rolled lamellar pearlite in annealing at the temperatures between 600 and $700^{\circ}C$ has been studied by quantitative micrography. It was foud that the spheroidization proceeded as two stageh. The first stage was the stage of relieving the stored energy by cold work, the second was the stage of reducing the interface energy between ferrite and cementite. The spheroidization rate combining the spheroidization rate of each stages is described by the following equation : $$d(1/S)/dt=k_3{\cdot}D/_{(1/s)}\{{\sigma}V/_{(1/s)}+k_4{\cdot}{\exp}(-bt)\}$$ Where, S is the total area of the interface between ferrite and cementite per unit volume, D is the diffusion coefficient, ${\sigma}$ is the boundary energy, V is the volume fraction of the cementite, and $k_3$, $k_4$, b are constants.

• Journal of the Korean Mathematical Society
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• v.41 no.1
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• pp.209-229
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• 2004

Let $\Sigma_{$\mid$\alpha$\mid$=m}\;s_{\alpha}z^{\alpha},\;z\;{\in}\;{\mathbb{C}}^n$ be a unimodular m-homogeneous polynomial in n variables (i.e. $$\mid$s_{\alpha}$\mid$\;=\;1$ for all multi indices $\alpha$), and let $R\;{\subset}\;{\mathbb{C}}^n$ be a (bounded complete) Reinhardt domain. We give lower bounds for the maximum modules $sup_{z\;{\in}\;R\;$\mid$\Sigma_{$\mid$\alpha$\mid$=m}\;s_{\alpha}z^{\alpha}$\mid$$, and upper estimates for the average of these maximum moduli taken over all possible m-homogeneous Bernoulli polynomials (i.e. $s_{\alpha}\;=\;{\pm}1$ for all multi indices $\alpha$). Examples show that for a fixed degree m our estimates, for rather large classes of domains R, are asymptotically optimal in the dimension n.