• 호남수학학술지
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• 제39권2호
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• pp.233-245
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• 2017

In the present paper we introduce and investigate an interesting subclass ${\mathcal{K}}^{(k)}_s({\gamma},p) $ of analytic and p-valently close-to-convex functions in the open unit disk ${\mathbb{U}}$. For functions belonging to this class, we derive several properties as the inclusion relationships and distortion theorems. The various results presented here would generalize many known recent results.

• Kyungpook Mathematical Journal
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• 제59권3호
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• pp.481-491
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• 2019

In the present paper, we investigate the upper bounds on third order Hankel determinants for certain class of close-to-convex functions in the unit disk. Furthermore, we obtain estimates of the Zalcman coefficient functional for this class.

• 호남수학학술지
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• 제42권4호
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• pp.719-731
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• 2020

In this article, we find some sufficient conditions under which the modified Lommel function is close-to-convex with respect to - log(1 - z) and ${\frac{1}{2}}\;{\log}\;\({\frac{1+z}{1-z}}\)$. Starlikeness, convexity and uniformly close-to-convexity of the modified Lommel function are also discussed. Some results related to the H. Silverman are also the part of our investigation.

• 대한수학회논문집
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• 제37권2호
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• pp.537-549
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• 2022

In this paper, we consider a convex univalent function f_α,β which maps the open unit disc 𝕌 onto the vertical strip domain Ω_α,β = {w ∈ ℂ : α < ℜ < (w) < β} and introduce new subclasses of both close-to-convex and bi-close-to-convex functions with respect to an odd starlike function associated with Ω_α,β. Also, we investigate the Fekete-Szegö type coefficient bounds for functions belonging to these classes.

• Korean Journal of Mathematics
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• 제30권4호
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• pp.629-642
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• 2022

In a recent paper, Sakar and Güney introduced a new class of bi-close-to-convex functions and determined the estimates for the general Taylor-Maclaurin coefficients of functions therein. The main purpose of this note is to give a generalization of this class. Also we point out the proof by Sakar and Güney is incorrect and present a correct proof.

• Korean Journal of Mathematics
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• 제32권1호
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• pp.73-82
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• 2024

The purpose of this paper is to introduce a new subclass of strongly meromorphic close-to-convex functions by subordinating to generalized Janowski function. We investigate several properties for this class such as coefficient estimates, inclusion relationship, distortion property, argument property and radius of meromorphic convexity. Various earlier known results follow as particular cases.

• Geomechanics and Engineering
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• 제6권5호
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• pp.469-485
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• 2014

A series of bearing capacity tests was conducted with eccentrically loaded model surface and shallow strip footings resting close to a slope to investigate behavior of such footings (ultimate loads, failure surfaces, load-displacement curves, rotation of footing, etc.). Ultimate loads of footing close to slope decreased with increasing eccentricity for both surface and shallow footings. Failure surfaces were not symmetrical, primary failure surfaces occurred on the eccentricity side (the slope side) and secondary failure surfaces occurred on the other side. Lengths of failure surfaces decreased with increasing eccentricity. Footings always rotated towards eccentricity side a few degrees. For eccentrically loaded footing, decrease in ultimate load with increasing eccentricity is roughly in agreement with Customary Analysis.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제10권4호
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• pp.265-271
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• 2003

Let $CS_\alpha(\beta)$ denote the class of normalized strongly $\alpha$-close-to-convex functions of order $\beta$, defined in the open unit disk $\cal{U}$ of $\mathbb{C}$${\mid}arg{(1-{\alpha})\frac{f(z)}{g(z)}+{\alpha}\frac{zf'(z)}{g(z)}}{\mid}\;\leq\frac{\pi}{2}{\beta}(\alpha,\beta\geq0)$ such that $g\; \in\;S^{\ask}$, the class of normalized starlike unctions. In this paper, we obtain the sharp Fekete-Szego inequalities for functions belonging to $CS_\alpha(\beta)$.

• 한국소음진동공학회논문집
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• 제14권11호
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• pp.1123-1128
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• 2004

An experimental study on firing noise of K2 rifle was performed. Firing noises of K2 rifle were measured at close distance to rifle. Firing noise of K2 rifle which made in Korea, has not measured before. The measurement of firing noise at close distance is not simple, because the amplitude of firing noise is much bigger than the measuring limit of ordinary sound level meter even though it uses a signal attenuator. The measurement of firing noise at close distance is necessary for noise source positioning and for obtaining the sound power of K2 rifle. By this experimental study, the firing noise levels of K2 rifle at different positions are obtained and these data can be used to Predict the sound pressure level at any distance from muzzle of the rifle. Also these data can be used to calculate the threshold shift of gunner's ear.

• 한국자동차공학회논문집
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• 제4권4호
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• pp.140-146
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• 1996

A large portion(above 70%) fo the hydrocorbon and NOx emissions for a typical vehicle occur mainly before the conventional underbody catalyst reaches activation temperature. To meet the stringent regulation as EC stage 2, the emissions produced during this period must be reduced. One of alternative techniques is to place CCC(Close-Coupled Catalyst) near the exhaust manifold. In this study, the characteristics of CCC are observed through EEC mode.