• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1999년도 가을 학술발표회 논문집
• /
• pp.317-324
• /
• 1999

Dynamic interaction analysis of surface structure on layered half-space is performed in frequency domain under incident wave excitation. This present study adopts a coupling method that combines the finite element(FE) for the flexible structures and boundary element(BE) for the layered half-space. A semi-analytical approach is employed to reduce the integration range of wavenumbers in the BE formula. For the incident wave input, the response is decomposed and formulated after the impedance matrix for the structure system. Numerical examples are presented to demonstrate the accuracy of the method. The examples show the feasibility of an extended application to the complicated dynamic analysis of structures on layered media under incident wave excitation.

• 한국전자파학회지:전자파기술
• /
• 제2권4호
• /
• pp.3-9
• /
• 1991

This paper presents the characteristics of antenna factors of half-wave resonance dipole antennas above a ground plane. The current distributions on a horizontal and vertical dipole antennas were analyzed by the Galerkin's method of moments, and these solutions are used for calculating the horizontal and vertical antenna factors above the ground plane. It is shown that accurate antenna factors of the horizontal and vertical dipole above the ground plane are required of the radiated emission test.

• 대한전자공학회논문지
• /
• 제15권3호
• /
• pp.7-10
• /
• 1978

이 논문은 single transistor를 사용하여 정현파를 전파정류하는 한 방법을 검토한다. switching으로 동작되는 inverter에 R-feed back을 하고 최적 parameter를 설정하므로써 도통상태의 반파와 cut-off 상태에서 feed back을 통한 반파를 합성하여 전파정류의 출력을 얻는다. cassette deck의 code재생 system에 이용한 바 효과적이었고, AGC 등에 이용 가능하다.

• Earthquakes and Structures
• /
• 제10권1호
• /
• pp.91-104
• /
• 2016

In this paper we investigate the existence of SH-waves in fiber-reinforced layer placed over a heterogeneous elastic half-space. The heterogeneity of the elastic half-space is caused by the exponential variations of density and rigidity. As a special case when both the layers are homogeneous, our derived equation is in agreement with the general equation of Love wave. Numerically, it is observed that the velocity of SH-waves decreases with the increase of heterogeneity and reinforced parameters. The dimensionless phase velocity of SH-waves increases with the decreases of dimensionless wave number and shown through figures.

• 한국광학회:학술대회논문집
• /
• 한국광학회 2006년도 동계학술발표회 논문집
• /
• pp.151-152
• /
• 2006

In this paper, a novel waveguide analysis is addressed based on the rigorous coupled wave analysis method. Using the proposed method, we can analyze half-infinite waveguide structures rigorously calculate.

• 한국해안·해양공학회논문집
• /
• 제22권1호
• /
• pp.10-17
• /
• 2010

투과성 이중 반원통 구조물과 경사 입사파간의 상호작용문제를 선형포텐셜 이론을 사용하여 살펴보았다. 투과성 이중 반원통 구조물은 바닥에 고정된 동심원상으로 배열된 2개의 원통 구조물로 이루어지며 각 원통 구조물의 전면은 일정한 공극율을 갖는 투과벽으로 후면은 투명한 벽으로 구성된다. 전면 투과벽의 공극율과 간격 그리고 파랑특성(주파수, 입사각)을 변화시키면서 파랑하중과 처올림 파형 그리고 파 차단성능을 살펴보았다. 파 차단 성능의 척도로서 차단영역내의 평균제곱 변위의 제곱근(R.M.S.)을 사용하였다. 투과성 반원통 구조물은 불투과성 구조물과 비교하여 차단영역내의 파도응답을 감소시키며 구조물에 작용하는 파랑하중을 크게 줄여준다. 특히 이중 구조물은 고주파주 영역에서 단일 구조물보다 파를 차단하는데 효과적이다.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 1996년도 추계학술발표회 논문집
• /
• pp.3-12
• /
• 1996

Cold fusion technologies now are being developed very successfully. The $\pi$-far infrared rays are generated from three dimensional crystallizing $\pi$-bondings of oxygen atoms in water molecules. The growing cavity in water molecules make near resonance state and a vortex of infrared rays and attracts $\pi$-far infrared rays in the water. The cavity surrounded by a lot of $\pi$-far infrared rays has a very strong gravitational field. The $\pi$-far infrared rays are contracted into $\pi$-far infrared rays of half wave length and of one wave length. The $\pi$-far infrared rays of half wave length generate heat while $\pi$-far infrared rays of one wave length are contracted into $\pi$-gamma rays of one wave length. The contracted $\pi$-gamma rays of one wave length make nucleons and mesons, which is the creation and transmutation of matter by covalent bondings and three-dimensional crystallizing $\pi$-bondings into implosion bonding. Patterson power cell generates a very strong gravitational cavity because the electrolysized oxygen atoms make $\pi$-far infrared rays than in plain water.

• 대한치과교정학회지
• /
• 제24권4호
• /
• pp.897-916
• /
• 1994

The biologic potential, which is different from the piezoelectric signals, relates tooth movement at least in part to changes in bone metaboliosm in bioelectric theory. The purpose of this experiment was to determine wheather the application of half sine-wave pulsed electromagnetic fields (HSPEMF) could increase both the rate and amount of orthodontic tooth movement. Forty-three male Hartley guinea pigs, weighting approximately 255g, were utilized in this study. The animals were 35 days old at the start of the study. Laterally directed orthodontic force was applied to the maxillary central incisors of 40 Hartley guinea pigs (20 experimental, 20 control). According to the amount of orthodontic force (6g, 12g), they were divided into two sub-groups (10 experimental I, 10 experimental II, 10 control I, 10 control II). During the experimental period, experimental animals were placed in plastic animal holders with their heads positioned in an area of uniform electromagnetic field. Control animals were placed in similar plastic holders that did not carry the electric apparatus. The results were as follows : 1. The application of a HSPEMF to the experimental groups significantly increase the final amount of orthodontic tooth movement observed over a 10-day experimental period. 2. The application of a HSPEMF to the experimental groups significantly increase the velocity of orthodontic tooth movement observed over a 10-day experimental period. 3. There was no significant difference in the final amount of orthodontic tooth movement at the fourth day to the eighth day, but there was significant difference in the final amount of orthodontic tooth movement at the nineth, tenth day during a 10-day experimental period. 4. After 10 days of HSPEMF exposure & orthodontic force, the experimental groups demonstrated more osteodasts in the pressure side than control groups.

• 한국추진공학회지
• /
• 제11권2호
• /
• pp.1-8
• /
• 2007

연소 안정화를 위해 로켓엔진 연소기에 장착될 수 있는 반파장 음향 공명기의 비선형 음향 감쇠 특성을 비선형 해석을 통해 조사하였다. 먼저, 공명기가 장착되지 않은 기본 연소실에 대해 넓은 범위의 진폭($80{\sim}150$ dB)을 갖는 음향 가진에 대한 연소실의 감쇠 거동을 조사한 결과, 진폭에 따라 연소실의 감쇠인자가 증가하며 125 dB 이상의 진폭에 대해서는 비선형 거동이 뚜렷이 나타남을 알았다. 반파장 공명기가 장착된 연소기에서의 계산 결과, 해당 공명기의 최적 동조조건은 진폭에 무관하였고, 높은 진폭의 압력파를 감쇠하는 기능은 유지되지만, 상대적으로 음향 공명기로서의 역할은 약화됨을 알 수 있었다.

• Structural Engineering and Mechanics
• /
• 제69권2호
• /
• pp.121-129
• /
• 2019

The present study investigates the propagation of shear waves in a composite structure comprised of imperfectly bonded piezoelectric layer with a micropolar half space. Piezoelectric layer is considered to be initially stressed. Micropolar theory of elasticity has been employed which is most suitable to explain the size effects on small length scale. The general dispersion equations for the existence of waves in the coupled structure are obtained analytically in the closed form. Some particular cases have been discussed and in one particular case the dispersion relation is in well agreement to the classical-Love wave equation. The effects of various parameters viz. initial stress, interfacial imperfection and micropolarity on the phase velocity are obtained for electrically open and mechanically free system. Numerical computations are carried out and results are depicted graphically to illustrate the utility of the problem. The phase velocity of the shear waves is found to be influenced by initial stress, interface imperfection and the presence of micropolarity in the elastic half space. The theoretical results obtained are useful for the design of high performance surface acoustic devices.