• Korean Journal of Mathematics
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• 제4권1호
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• pp.65-70
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• 1996

In this note, we study a relation between harmonic maps and exponential harmonic maps, and we show existence of Yang-Mills connections.

• 충청수학회지
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• 제22권4호
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• pp.749-756
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• 2009

In this paper, we obtain some coefficient bounds of harmonic univalent mappings on $\Delta=\{z\;:\;{\mid}z{\mid}\;>\;1\}$ which are starlike, convex, or convex in one direction.

• Korean Journal of Mathematics
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• 제20권4호
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• pp.433-439
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• 2012

In this paper, we study harmonic, orientation-preserving, univalent mappings defined on ${\Delta}$ = {z : |z| > 1} that have real coefficients or starlike analytic functions and obtain some coefficients bounds.

• Journal of applied mathematics & informatics
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• 제18권1_2호
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• pp.377-381
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• 2005

We present a convenient recursive formula for the sums of alternating harmonic series of odd order. The recursion is obtained by expanding in Fourier series certain elementary functions.

• 충청수학회지
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• 제17권2호
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• pp.163-167
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• 2004

In this paper, we obtain some coefficient estimates of harmonic, orientation-preserving, univalent mappings defined on ${\Delta}$ = {z : |z| > 1}.

• 충청수학회지
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• 제33권1호
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• pp.1-7
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• 2020

In this paper, it is shown that the reversible harmonic Finsler metrics on spheres must be Riemannian.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제15권3호
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• pp.217-220
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• 2008

In this paper, we investigate the harmonic mappings that arise in connection with Scherk's surface and helicoid.

• 조명전기설비학회논문지
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• 제20권2호
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• pp.68-74
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• 2006

고조파 전류에 의한 배선용 차단기 오동작 및 원인불명 동작이 보고되고 있으나 고조파 전류에 의한 배선용 차단기 동작을 설명할 수 있는 자료가 없는 실정이다. 본 논문에서는 네 가지 형태의 배선용 차단기(열동식, 열동 전자식, 완전 전자식 및 전자식)에 대해 고조파 전류의 영향을 시험하였다. 실험 결과 정격전류 이하의 고조파가 포함된 시험 전류에서는 어떤 종류의 배선용 차단기에서도 오동작은 발생하지 않았다. 그리고 다양한 고조파 부하 조건에서 열동식과 열동 전자식의 경우 제조사의 동작 시간에 별다른 영향을 보이지 않았다. 그러나 완전 전자식 차단기는 과부하 조건에서 고조파 전류가 증가할 수 록 동작 시간이 점차 둔화되었고 이는 케이블 과열을 야기할 수 있을 것이다. 따라서 고조파 전류가 심한 곳에서는 완전 전자식 배선용 차단기의 사용을 피해야 할 것이다.

• 한국농공학회논문집
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• 제50권2호
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• pp.19-26
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• 2008

This study has been carried out to investigate the dynamic characteristics of RC slabs. For this purpose, the 20-node solid element has been used to discretize the RC slabs into two parts of concrete and rebar. The material non-linearity considering elasto-visco plastic model and the smeared crack model have been adopted in the finite element formulation. The applied load can handle step load, load intensity of harmonic load, area of distributed load and frequency. The frequency of harmonic load has an significant effect on dynamic behaviour in terms of displacement. As the frequency is increased, the effect of load amplitude is more serious. Especially, if the frequency of harmonic load exceeds 30 Hz, it is noted that the displacement by harmonic load is greater than that by step load. In case of harmonic load, the damping effect shows no certain tendency with respect to frequency of load. In details, the damping is effective when the frequency of harmonic load is 2 Hz, but there is no consistent tendency according to damping ratio. The dynamic response when the frequency of harmonic load is 3 Hz shows same result for undamped case as well as for damped case with 5% damping ratio. It is also noted that we can get the largest deflection for damped case with 1% damping ratio. However, there is not any damping effect when the frequency of harmonic load is greater than 4 Hz.

• 한국분말재료학회지
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• 제24권2호
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• pp.128-132
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• 2017

Harmonic structure materials are materials with a core-shell structure having a shell with a small grain size and a core with a relatively large grain size. They are in the spotlight because their mechanical properties reportedly feature strength similar to that of a sintered powder with a fine grain size and elongation similar to that of a sintered powder with a coarse grain size at the same time. In this study, the tensile properties, microstructure, and stretch-flangeability of harmonic structure SUS304L made using powder metallurgy are investigated to check its suitability for automotive applications. The harmonic powders are made by mechanical milling and sintered using a spark plasma sintering method at 1173 K and a pressure of 50 MPa in a cylindrical die. The sintered powders of SUS304L having harmonic structure (harmonic SUS304L) exhibit excellent tensile properties compared with sintered powders of SUS304L having homogeneous microstructure. In addition, the harmonic SUS304L has excellent stretch-flangeability compared with commercial advanced high-strength steels (AHSSs) at a similar strength grade. Thus, the harmonic SUS304L is more suitable for automotive applications than conventional AHSSs because it exhibits both excellent tensile properties and stretch-flangeability.