• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.2
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• pp.94-103
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• 1991

This study was carried out to investigate the engineering characteristics of the R.C circular ring sector plate with various boundary conditions and then to propose a rational and paraical method for application of finite element method to R.C structures. The stiffness matrix of the circular ring sector plate was obtained by using the multi-base coordinate system in which the base-coordinate systems were constructed for each nodal point of the quadrilateral element in order to reflect the complicated boundary conditions conveniently and correctly. The R.C element stiffness matrix was constructed by adding the stiffness coefficients of the steel-bar element into the plate bending element stiffness matrix. Herein, the steel-bar element was treated as the common beam element. Using the above method, the effects of steel-bar can be considered without increasing of the numbers of element and nodal points.

• Journal of the Korean Mathematical Society
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• v.59 no.5
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• pp.945-962
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• 2022

For a positive integer ℓ, $\bar{A}_{\ell}(n)$ denotes the number of over-partitions of n into parts not divisible by ℓ. In this article, we find certain Ramanujan-type congruences for $\bar{A}_{r{\ell}}(n)$, when r ∈ {8, 9} and we deduce infinite families of congruences for them. Furthermore, we also obtain Ramanujan-type congruences for $\bar{A}_{13}(n)$ by using an algorithm developed by Radu and Sellers [15].

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5838-5842
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• 2011

The study mainly aims to explore how deterioration of motor control center, namely MCC, and vibration put impact on temperature of bus bar as well as temperature change of bolt-nut joint. The motor control center consists of three internal parts (i.e. R, S, T) which are for motor operation of high capacity. Two dimensional mechanism for measuring temperature was designed and manufactured with infrared temperature sensor. Installing it in inner motor control center enabled researcher to monitor temperature of bus bar as well as amount of change of current regularly. Temperature change of bus bar according to load was primarily examined based on a bolted joint in the experiment. It was clearly verified that temperature change of bus bar was proportional to current consumption. Therefore, installing non-contact two dimensional mechanism for measuring temperature in motor control center would be expected to prevent temperature rise owing to overload current and power outage as well as fire accident which can be triggered by poor electrical contact.

• Korean journal of applied entomology
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• v.20 no.1 s.46
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• pp.37-41
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• 1981

Mycelial growth and production of macroconidia by Cylindrocladium crotalariae on either PDA or water agar containing soybean leaf pieces adjusted to different water potentials with KCI. were consistently maximal at -14bars. Mycelial growth by this fungus was nii at about -100 bars and below at 30C, -80 bars and below at 25C and -64 bars and below at 20C. Sporulation was prevented at -64 bars and below at $20^{\circ}C\;and\;25^{\circ}C$. Perithecial andmicrosclerotial formation was maximal at abot -1.4 to - 3.0 bars (the basal medium without sait). Percentage of spore germination for this fungus was uniformly maximal at all water potentials between -1.4 bars (the highest tested) and - 20 bars, was progressively less as the water potential lowered below -20 bars, and was prevented at - 60 bars.

• Bulletin of the Korean Mathematical Society
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• v.32 no.2
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• pp.179-189
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• 1995

Let $V \subset R^n$ be a convex homogeneous cone which does not contain straight lines, so that the automorphism group $$ G = Aut(R^n, V)^\circ = { g \in GL(R^n) $\mid$ gV = V}^\circ $$ ($\circ$ denoting the identity component) acts transitively on V. A convex cone V is called "self-dual" if V coincides with its dual $$ (1.1) V' = { x' \in R^n $\mid$ < x, x' > > 0 for all x \in \bar{V} - {0}} $$ where $\bar{V}$ denotes the closure of V.sure of V.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.712-723
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• 2015

This study was conducted to develop the SWCC estimation equation using scaling technique, and to investigate relative sensitivity of the SWCC according to the soil water tension, for the four kinds of soil texture such as Sand [S], Sandy Loam [SL], Loam [L] and Clay Loam [CL]. The SWCC estimation equation of scale factor [${\Theta}sc$] (Eq. 1) was developed based on the log function (Eq. 2) and exponential function (Eq. 3). ${\Theta}sc=[({\Theta}-{\Theta}r)/({\Theta}s-{\Theta}r)]$ (Eq. 1) ${\Theta}sc=-0.196ln(H)+0.4888$ (Eq. 2) ${\Theta}sc=0.3804(H)^{(-0.448)}$ (Eq. 3) where, ${\Theta}$: water content (g/g %), ${\Theta}s$: water content at 0.1bar, ${\Theta}r$: water content at 15bar, H: soil water tension (matric potential) (bar) Relative sensitivity of soil water content was decreased as increase soil water tension, those according to soil water tension were 0.952~0.620 compared to 0.1bar case. Relative sensitivity of scale factor was also decreased as increase soil water tension, those according to soil water tension were 0.890~0.577 compared to 0.2bar case.

• Structural Engineering and Mechanics
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• v.83 no.6
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• pp.799-810
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• 2022

This study investigated the effect of the strengthening efficiency of unbonded steel-bar truss system on the out-of-plane behavior of perforated masonry walls. Four full-scale unreinforced masonry (URM) walls with two different planes were prepared using the unbonded steel-bar truss system and a URM walls without strengthening. All masonry walls were tested under constant axial and cyclic lateral loads. The obtained test results indicated that the pinching effect in the out-plane behavior of masonry walls tends to decrease in the in- and out-of-plane strengthened URM walls using the unbonded steel-bar truss system with the higher prestressing force ratio (R_p) of vertical reinforcing bars in the unbonded steel-bar truss system, regardless of the perforated type of the masonry wall. Consequently, the highest maximum shear resistance and cumulative dissipated energy at peak load in the post-peak behavior were observed in the in- and out-plane strengthened URM walls with the highest R_p values, which are 2.7 and 6.0 times higher than those of URM. In particular, the strengthening efficiency of the unbonded steel-bar truss system was primarily attributed to the vertical prestressed steel-bars rather than the diagonal steel-bars, which indicates that the strains in the vertical prestressed steel-bars at the peak load were approximately 1.6 times higher than those in the diagonal steel-bars.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.95-103
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• 2010

Roll to Roll (R2R) is one of the most promising production technologies in the printed electronics such as OLEDs, e-paper, backplanes, RFID because this technology can save production cost and increase production speed. Printed electronics includes various processes such as printing, drying, winding, unwinding, and so on. In printed electronics R2R system, air-flotation oven is employed for drying process. Therefore, it is essential to introduce efficient and fast drying process when printing is finished. This paper considers the analysis of drying process in R2R that involves hot air flow. Air-flotation oven consists of non-contact supports and drying of coated web materials such as plastic films and paper. In this paper, experimental results and numerical analysis of pressure-pad air bar are investigated. The aerodynamic characteristics of pressure-pad air bar are numerically calculated using computational fluid dynamics (CFD) approach. Then the measured values of the aerodynamic forces for air bars are compared with those of CFD analysis.

• Journal of the Korean Institute of Gas
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• v.17 no.5
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• pp.1-7
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• 2013

In this study, simulation work of HCNG refueling system was performed. The hydrogen was produced from steam reforming process by natural gas. The conversion of natural gas is increased as SCR is increased. but it was no significant difference more than 3 of SCR and fuel throughput is increased as GHSV is increased. Both conversion and fuel throughput levels was optimized when the $1700h^{-1}$ of GHSV. CNG was compressed from low pressure natural gas. For the mixing of $H_2$ and CNG is mixed with the high pressure conditions such as 400bar of $H_2$ and 250bar of natural gas. Single-stage compression was required more power than multi stage. So, multi stage compression was suggested for high pressure compression. We calculated the intermediate pressure to minimize total required power of compressors. The intermediate pressure for $H_2$ and natural gas were derived at 61 and 65 bar, respectively.

• Journal of Korean Medicine for Obesity Research
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• v.12 no.2
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• pp.44-55
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• 2012

Objectives: The purpose of this study is to investigate biological effects of Euiiin-tang(Y$\grave{i}$y$\check{i}$r$\acute{e}$n-t$\bar{a}$ng) extracts by extraction methods. Methods: To investigate the effects of anti-oxidative and anti-inflammatory activity, we measured DPPH radical scavenging assay, collagenase inhibition assay and COX-2 inhibition assay. Results: In case of measuring anti-oxidative and anti-inflammatory activities of Euiiin-tang(Y$\grave{i}$y$\check{i}$r$\acute{e}$n-t$\bar{a}$ng) by collagenase and COX-2 inhibition activity, it came out that Euiiin-tang(Y$\grave{i}$y$\check{i}$r$\acute{e}$n-t$\bar{a}$ng) was unable to inhibit collagenase, but was effective to inhibit COX-2. Cytotoxicity analysis of Euiiin-tang(Y$\grave{i}$y$\check{i}$r$\acute{e}$n-t$\bar{a}$ng) extracts by MTT assay principles, there was no cytotoxicity in aqueous and 50% ethanol extracts in any level of concentration. Conclusions: This results suggest that Euiiin-tang(Y$\grave{i}$y$\check{i}$r$\acute{e}$n-t$\bar{a}$ng) extracts have anti-oxidative and anti-inflammatory activities.