• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.430-433
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• 2005

Laser bonding between similar and dissimilar thermoplastics has been investigated by making use of laser transmission weld technique. Spot welding of two layers of plastic materials has been demonstrated by using of a high-quality diode-laser with 808nm wavelength. Weld areas increases according to power density, exposure time. The results of peel out test show that peel strengths increase with the area of molten plastics. Layers, which have the same chemical properties, have good bonding qualities. A bonding method which dye film is coated on the interface is used for laser bonding between plastics with high transmission for laser wavelength. Laser transmission bonding is worthy of attention because it is not in contact, requires a few tooling devices, allows a flexible energy delivery and produces nearly invisible welds

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.634-642
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• 1998

This paper deals with the analytical model of an elastic porous material in sound transmission loss of a double panel with fiber glasses. From the parametric analysis, it is concluded that the boundary condition, which is concerned to the contact between the skin panel and core materials, does not have much influence on sound transmission loss of a double panel with fiber glasses, and material properties of the porous material become, however, important factors to mass-spring-mass resonance. The comparisons of the prediction with the measurement of sound transmission loss of walls show good agreement between the two values.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.1085-1089
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• 2007

An acoustic topology optimization method is developed to optimize the acoustic attenuation capability of a muffler. The transmission loss of the muffler is calculated by using the three-point method based on finite element analysis. Each element of the finite element model is assumed to have the variable acoustic properties, which are penalized by a carefully-selected interpolation function to yield clear expansion chamber shapes at the end of topology optimization. The objective of the acoustic topology optimization problem formulated in this work is to maximize the transmission loss at a target frequency. The transmission loss value at a deep frequency of a nominal muffler configuration can be dramatically increased by the proposed optimization method. Optimal muffler configurations are also obtained for other frequencies.

• International Journal of Precision Engineering and Manufacturing
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• 제3권3호
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• pp.28-36
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• 2002

The continuously variable transmission (CVT) mechanism considered here is the output coupled type which combines the functions of a 2K-H I type differential gear unit and a V-belt type continuously variable unit (CVU). One shaft of the CVU is connected directly to the output shaft and another shaft of it is linked to the differential gear unit. It is shown that some fundamental relations (speed ratios, power flows and efficiencies) for twelve mechanisms previously described are valid by various experimental studies, six of them produce a power circulation and the others produce a power split. Parametric analysis is carried out in relation to the efficiency, speed ratio and power ratios in order to assist in the design of an optimum configuration. Some useful properties associated with power flow modes also are discussed in the output coupled type continuously variable transmission.

• 한국소음진동공학회논문집
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• 제17권11호
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• pp.1013-1020
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• 2007

In this paper, the predictions and measurements of sound transmission loss(STL) are discussed for various types of acoustical materials and carpets. Random incidence sound transmission losses are measured by the sound intensity method. The in-house software HONUS2005 is used to predict TL and estimate the various physical properties such as the flow resistivity, the structure factor, the porosity, the Possion's ratio, and etc. After this estimation, various multi-layered materials with a steel plate are measured and predicted. In particular, Carpets are assumed to be membranes to predict acoustical performance. To confirm this assumption, double and triple-layered cases are also observed including two different kinds of carpets.

• 한국안광학회지
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• 제8권1호
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• pp.23-28
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• 2003

랩온어칩을 위한 변환 가능한 RGB 색상 필터를 연구하였다. 잉크 색상 필터는 PDMS 패턴과정에 의한 공정으로 제작하였고, 칼라 필터의 자외선-가시광선 영역의 광투과율을 조사하였다. 잉크 칼라 필터는 스펙트럼의 모양과 기울기에 의해 특성 지워진다. 적색/황색 필터의 투과는 600 nm와 500 nm에서 차단스펙트럼 모양을 가지는 곡선으로 구성되었다. 잉크 필터의 청색 출력은 80% 피크 투과율과 약한 적색 누수를 보였다. 한편 녹색 잉크 필터는 48% 피크 투과율과 적색 누수 투과를 보였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.285-290
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• 2011

For developing acoustic window, transmission loss in accordance with incident angle was calculated and compared with measurement results. In design stage, the material choice of acoustic window is very important because the material is parameter of transmission loss and structural strength. In order to analyze the effect of material properties on transmission loss, the parametric studies were carried out and the results were discussed in this paper.

• 한국소음진동공학회논문집
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• 제21권10호
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• pp.890-896
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• 2011

For developing acoustic window, transmission loss in accordance with incident angle was calculated and compared with measurement results. In design stage, the material choice of acoustic window is very important because the material is one of main parameters of transmission loss and structural strength. In order to analyze the effect of material properties on transmission loss, the parametric studies were carried out and the results were discussed in this paper. And, to verify the design specification of acoustic window, measurement was carried out and the results were compared and analyzed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.1001-1004
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• 2002

Accurate prediction of the transmission loss of dissipative silencers has been considered difficult due to the ambiguity and complexity in the physical properties of sound absorbing materials. Additional difficulty lies in the fact that the analytical calculation of the propagation constant is unknown yet. In this paper. as a first step toward obtaining the Propagation constant and thus predicting the transmission loss, an approximation equation stemming from the wave analysis in the lined interior has been derived. Such an analytical solution and numerical solution using the boundary element method are compared for a two-dimensional simple dissipative silencer under the assumption of the locally reacting sound absorbent.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.476-479
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• 2002

The ageing cause in many porcelain suspension insulators which occur on transmission and distribution line with dead-end stings is mechanical stress in interface between porcelain and cement materials. It is known that the principal mechanical stress which give electrical failure is the results of the displacement is due to cement growth. We studied the effect of cement displacement resulting environmental ageing parameters on porcelain insulator mechanical properties for transmission line by simulation (ANSYS/NASTRAN program) and test methods. These simulation analysis and experimental results show that cement volume growth affects severely to be mechanical failure ageing.