• Journal of the Chungcheong Mathematical Society
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• v.32 no.2
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• pp.225-238
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• 2019

We show the boundedness and uniform Lipschitz stability for the solutions to the functional perturbed differential system $$y^{\prime}=f(t,y)+{\normalsize\displaystyle\smashmargin{2}{\int\nolimits_{t_0}}^t}g(s,y(s),\;T_1y(s))ds+h(t,y(t),\;T_2y(t))$$, under perturbations. We impose conditions on the perturbed part ${\int_{t_0}^{t}}g(s,y(s)$, $T_1y(s))ds$, $h(t,y(t)$, $T_2y(t))$, and on the fundamental matrix of the unperturbed system y' = f(t, y) using the notion of h-stability.

• Journal of ILASS-Korea
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• v.26 no.1
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• pp.33-39
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• 2021

Y-jet nozzle has a wide fuel flow rate range and turn-down ratio, thus, it is used in industrial boilers, furnace and agricultural atomizer. However, it has asymmetrical spray characteristics due to the nozzle design factors. Therefore, in this study, asymmetric spraying characteristics of the elliptical Y-jet nozzle was studied by using the lab-scale spray apparatus. As a result, the elliptical Y-jet nozzle had lower gas mass flow rate than circular Y-jet nozzle at same gas pressure, because of bigger shear stress due to the wider inner surface at the elliptical Y-jet nozzle. Larger SMD was measured on the elliptical Y-jet nozzle than the circular Y-jet nozzle. When SMD was measured in the X_Axis direction at the same gas mass flow rate, the elliptical Y-jet nozzle with an aspect ratio of 2:1 showed greater asymmetry than the others.

• Bulletin of the Korean Mathematical Society
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• v.47 no.3
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• pp.491-502
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• 2010

In this paper, we obtain the general solution and the generalized Hyers-Ulam Rassias stability of the functional equation f(2x + y) + f(2x - y) = 4(f(x + y) + f(x - y)) - $\frac{3}{7}$(f(2y) - 2f(y)) + 2f(2x) - 8f(x).

• Honam Mathematical Journal
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• v.29 no.4
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• pp.543-554
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• 2007

In this paper, we prove the stability of a mixed type functional equation f( -x + y + z) + f(x - y + z) + f(x + y - z) = f(x - y) + f(y - z) + f(z - x) + f.(x) + f(y) + f(z).

• The Pure and Applied Mathematics
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• v.27 no.1
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• pp.51-60
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• 2020

In this note, we investigate the Hyers-Ulam stability and the hyperstability of the Pexider type functional equation g(x + y + xy) = g(x) + f(y) + xf(y) + yg(x).

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.89.2-89
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.11a
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• pp.155-155
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• 2002

• Korean Journal of Poultry Science
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• v.12 no.1
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• pp.39-44
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• 1985

These studies were conducted to compare the nutritive values and optimum prices of eggs among 6 groups of different egg Weight. With the total of 100 eggs of each weight group, after the weight percentage of egg yolk, albumen and shell in the whole egg were investigated, protein and fat contents of e99 yolk and albumen were analyzed. and then protein and fat contents in the whole eggs were calculated. Finally, the optimum prices of eggs in relation to the egg weight were studied on the basis of egg weight, protein content and protein plus fat contents of eggs, respectively. The results obtained are summarized as follows; 1. As the egg weight (X, g/10 eggs) increased, egg yolk (Y$_1$, %) and shell(Y$_2$, %) percentages tended to decrease, but egg albumen(Y$_3$, %) percentage increased lineally; Y$_1$=44.34-0.02X, Y$_2$=15.358-0.006 X, and Y$_3$=40.136＋0.026 X. 2. There were no significant differences in protein and fat contents of eggs among 6 different groups of egg weight. 3. Protein (Y$_1$, %), fat (Y$_2$, %) and protein plus fat (Y$_3$, %) contents in the whole eggs declined progressively as the egg weight (X, g/10 eggs) increased ; Y$_1$=11.943-0.00032X, Y$_2$=13.996-0.00614X, and Y$_3$=25.939-0.00646X. 4. Similar results were obtained whether the optimum prices of eggs were estimated on the basis of egg weight or protein content of eggs, and they were higher in the large size eggs and lower in the small size eggs than the optimum prices of eggs estimated on the basis of protein plus fat content of eggs.

• Journal of the Korean Society of Tobacco Science
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• v.1 no.2
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• pp.93-102
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• 1979

Chemical compositions of Flue - cured and Burley tobacco leaf and smoke were analyzed to find out simple correlation between compositions. Based on the simple correlation ( $r$ ) data, four regression equations were obtained for dry condensate and nicotine in smoke as follows, $Y_{FT}=\;0.816+4.638X_1+0.346X_2$......................................(1) $Y_{BT}=\;0.235+0.884X_3-0.088X_4$......................................(2) $Y_{FN}=\;0.015+0.090X_5+0.476X_1$......................................(3) $Y_{BN}=-0.026+0.101X_3-0.006X_4$.........................................(4) where, $Y_{FT}$ : dry condensate (mg/cig.) in cigarette smoke of Flue-cured $Y_{BT}$ : dry condensate (mg /cig. ) in cigarette smoke of Burley $Y_{FN}$ : nicotine contents (mg/cig.)in cigarette smoke of Flue-cured $Y_{BN}$ : nicotine contorts (mg/cig. ) in cigarette smoke of Burley $X_1$ : total alkaloid contents (%) of Flue-cured $X_2$ : curde ash contents (%)of Flue -cured $X_3$ : alcohol -benzene extract contents (%) of Burley $X_4$ : curde ash contents (%) of Burley $X_5$ : hexane extract content (%) of Flue -cured Standard deviation for regressions equations were obtained respectively. equation(1),$\pm$3.16 : equation (2),$\pm$1.94 : equation (3),$\pm$0.35 , equation (4) $\pm$ 0.33. Regression equations between dry condensate and nicotine contorts in cigarette smoke were also obtained in the forms of equation(5) and(6) $Y_{FN}$= 0.274 $Y_{FT}$- 3.259............................(5) $Y_{BN}$= 0.249 $Y_{BT}$ - 2.093.............................(6) Standard deviations, $\pm$ 0.061 and $\pm$ 0.152, were obtained for regression equation(5) and (6) respectively.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.811-821
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• 2020

Mycobacterium tuberculosis produces mycolic acids which are relevant for persistence, recalcitrance to antibiotics and defiance to host immunity. c-di-GMP is a second messenger involved in transition from planktonic cells to biofilms, whose levels are controlled by diguanylate cyclases (DGC) and phosphodiesterases (PDE). The transcriptional regulator dosR, is involved in response to low oxygen, a condition likely happening to a subset of cells within biofilms. Here, we found that in M. bovis BCG, expression of both BCG1416c and BCG1419c genes, which code for a DGC and a PDE, respectively, decreased in both stationary phase and during biofilm production. The kasA, kasB, and fas genes, which are involved in mycolic acid biosynthesis, were induced in biofilm cultures, as was dosR, therefore suggesting an inverse correlation in their expression compared with that of genes involved in c-di-GMP metabolism. The relative abundance within trehalose dimycolate (TDM) of α-mycolates decreased during biofilm maturation, with methoxy mycolates increasing over time, and keto species remaining practically stable. Moreover, addition of synthetic c-di-GMP to mid-log phase BCG cultures reduced methoxy mycolates, increased keto species and practically did not affect α-mycolates, showing a differential effect of c-di-GMP on keto- and methoxy-mycolic acid metabolism.