• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.10
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• pp.681-686
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• 1999

In this study, a windmill type ultrasonic motor operated by single-phase AC electric field was fabricated, and then revolution characteristics and 3-dimensional vibration mode of the ultrasonic motor were investigated. Brass metal was pressed with umbrella-type using metal mold, then slot of 4 kind was processed at various thickness. It was found that the revolution speed of the ultrasonic motor increased with decreasing the thickness of elastic body. The revolution speed of the ultrasonic motor increased with increasing the slots of elastic body. When the characteristics was measured, applied voltage was changed from $10V_{max}\; to\; 100V_{max}$. Then, revolution was began from $30V_{max}$, if voltage was applied over $90V_{max}$ revolution speed was saturated, and not increased. The maximum revolution speed was 510[rpm] when using elastic body with 6 slots and thickness of 0.15mm. And 3-dimensional displacement mode was rotated clockwise direction.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.749-751
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• 1998

In this study, the wind-mill type ultrasonic motor was fabricated, and then revolution and temperature characteristics of the ultrasonic motor were measured. Brass metal was pressed with umbrella-type using metal mold, then slot of 4 kind was processed in each of thickness. Among sixteen's ultrasonic motors, heat loss on applied voltage was much at stator of the highest resonant point, but heat loss on applied voltage was almost neglected at the lowest resonant point of stator. The thickener thickness of elastic body, revolution speed was decreased. The more slot of elastic body, revolution speed was increased. Applied voltage was changed from $10V_{max}$ to $100V_{max}$. When applied voltage was under $20V_{max}$, ultrasonic motor was not rotated. When applied voltage was over $90V_{max}$, revolution of ultrasonic motor was saturated. Maximum revolution speed was 510[rpm].

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.2
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• pp.130-138
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• 1988

The method of conjugate gradient (C.G.M.) is applied to the solution of current distribution from body of revolution(B.O.R.). Using the C.G.M., it is possible to analyze electrically large arbitratily oriented B.O.R.. The fundamental differencess between C.G.M. and moment are outlined. This method converge for any initial guess, and this techniqe guarantees a monotonic convegence. Numerical resulsts are presented for electromagnetic case which shows good agreements with moment solution.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1987.04a
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• pp.184-187
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• 1987

The method of Conjugate Gradient(C.G.M) is applied to the solution of current distribution from body of revolution (B.O.R).Using the C.G.M it is possible to analyze electrically large arbtrarily oriented B.O.R. The fundamental differences between C.G.M and moment method are outlined. This method converges for any initial guess and this techniqe gurantees a monotonic convergence. Numerical results are presented for electromagnetic case which show good agreement with moment solution.

• Bulletin of the Society of Naval Architects of Korea
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• v.23 no.1
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• pp.13-22
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• 1986

Axisymmetric turbulent thick boundary layers on a rotating body of revolution are calculated numerically in the paper. Richardson number is introduced to the mixing length to take account of swirl effects on Reynolds stresses. Interactions of the boundary layer and the external potential flow are included by adding the displacement thickness of boundary layers on the original body. Pressure distributions on the body surface are estimated by integrating normal momentum equation across the boundary layer. A model is designed and tested in the wind tunnel. Mean velocities are measured. Through the present study, swirl effects on the thick axisymmetric boundary layer development are considerable in comparison with those of non-totating cases. Rotational motion generally increase boundary layer thickness, axial skin friction coefficients, and form drags. Circumferential flow can be reversed to induce negative skin friction when the section area is reduced.

• Journal of Biomedical Engineering Research
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• v.35 no.2
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• pp.26-34
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• 2014

Little information is available about the characteristics in revolution gait of hemiplegic elderly, which is frequently represented in daily life. It is also hard to elucidate purely the characteristics due to hemiplegia because of no consideration of aging factors. The aim of study is to identify the alteration characteristics of lower extremity joint angles in both straight and revolution gaits together due to hemiplegia through comparing healthy with hemiplegic elderly. Following Institutional Review Board approval, twelve healthy and hemiplegic elderly were participated and the center of body mass (COM) and lower extremity joint angles were measured during straight and revolution gaits using a computer-aided video motion capture system. The results showed that the gait characteristics were generally altered in both straight and revolution gaits due to hemiplegia (p < 0.05). The gait characteristics were then different between the straight and revolution gaits each other. This study may be valuable by identifying for the first time the alterations of the lower extremity joint angles in both straight and revolution gaits due to pure hemiplegia through comparing healthy elderly with hemiplegic elderly.

• 한국기계연구소 소보
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• s.9
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• pp.141-151
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• 1982

An iterative procedure for the calculation of the thick axisymmetric boundary layer and wake near the stern of a body of revolution is presented. Procedure consists of the potential flow calculation by a method of the integral equation of first kind and the calculation of boundary layer and wake by a differential me¬thod of the boundary layer theory. Additionally, higher order terms are included in the conventional momentum equations and continuity equation for the consider¬ation of the characteristics of axisymmetric flow different from the one of two dimentional flow and the thick boundary layer. These solutions are matched at the edge of boundary layer and wake. The results obtained by the present me¬thod are compared with the experimental data and it is found that the nominal wake distribution at the propeller plane of a axisymmetric body is in good agree¬ment with the experiment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.225-230
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• 1994

EFIE`s(Electric Field Integral Equations) are widely used in formulation of electric field problems and these equations are analyzed by several numerical method. In formulation of EFIF by forcing the tangential component of electric field on the perfect conducting body be zero, we can obtain equation with a kernel that has a logarithmic singularities. In this paper, an integral equation is presented which can be used for perfect BOR(Body of Revolution) objects and this can be more simplified for straight wire problem. As examples, monopole antenna which is driven by coaxial cable and scattering problems are considered.

• Journal of Korean Medical classics
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• v.23 no.1
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• pp.187-202
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• 2010

Han Dongseok advocated his own unique viewpoint about Universal Revolution based on Jeong-yeok(正易), and newly explained Exchange between Metal and Fire[金火交易]. Although he was not a researcher that had developed Jeong-yeok(正易), he has been judged as a utilitarian that tried to apply Change theory[易學] to realistic field called Oriental Medicine. The reason that such efforts are valuable is that he extended one of cosmological theory that is to say Jeong-yeok(正易) to the exchange of human body based on space-time progress. Theoretically he proved Jeong-yeok(正易) with the thought that heaven and human beings correspond to each other, realistically he showed turning point that as a main agent in Universal revolution we can change our own lives, in "The Principles of Universal Revolution", which is his most famous work.

• Journal of Korea Technology Innovation Society
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• v.6 no.2
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• pp.253-264
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• 2003

철강산업은 자동차용 강판 공급체인의 총체적 측면에서 볼 때 자동차산업의 핵심 공급자로서 중요한 역할을 수행하고 있다. 1990년대 초반 이후 자동차용 바디 제조공정에 테일러 웰디드 브랭크, 하이드로포밍 등 첨단금속소재 가공기술이 다양한 부위에 널리 적용되고 있다. 한편 자동차업계 및 철강업계는 설비 공급과잉에 따른 치열한 생존경쟁이 전개되는 가운데 이들 업계를 둘러싼 경영환경이 급속히 변화하고 있다. 본 연구에서는 기술혁신 및 경영 환경변화가 급속하게 전개되는 글로벌 마켓에서 자동차 바디용 강판 공급체인 상의 철강업체 역할 변화를 고려하고자 한다. 철강산업은 완성차업체 및 자동차 최종고객을 만족시키기 위한 원가절감 전략을 구현하는 동시에 소재 프로세싱 분야에 대한 기술역량을 축적하여야 한다. 이것이 현재 경쟁업체, 신규진입업체 및 대체 소재산업들과의 경쟁환경에서의 철강업체의 성공전략이다.