• KIEE International Transactions on Electrophysics and Applications
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• 제4C권1호
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• pp.10-14
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• 2004

A large area electron beam generator has been developed for industrial applications, for example, waste water cleaning, flue gas treatment, and food pasteurization. The operational principle is based on the emission of secondary electrons from the cathode when ions in the plasma contact the cathode, which are accelerated toward the exit window by the gradient of the electric potential. Conventional electron beam generators require an electron beam scanning mechanism because a small area thermal electron emitter is used. The electron beam of the large area electron beam generator does not need to be scanned over target material because the beam area is considerable. We have fabricated a large area electron beam generator with peak energy of 200keV, and a beam diameter of 200mm. The electron beam current has been investigated as a function of accelerating voltage and distance from the extracting window while its radial distribution in front of the extracting window has been also measured.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.154-157
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• 2005

The use of electron-beam(E-Beam) manufacture systems provides a means to alleviate optic exposure equipment's problems. We designed an E-beam manufacture system with SEM function. Optimal beam scanning is one of the most important conditions in the performance of E-beam and SEM. The performance of E-beam manufacture system and images of SEM are a close affinity with each other. Developed E-beam manufacture system consist of the controllers of high voltage, scanning, optic and high voltage generator. In this paper, we analyze the condition of steady beam scanning and describe the development of controller fer optimal beam scanning.

• Coupled systems mechanics
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• 제5권2호
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• pp.157-190
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• 2016

This paper deals with frequency analysis of Euler-Bernoulli beams carrying an arbitrary number of Kelvin-Voigt viscoelastic dampers, subjected to harmonic loads. Multiple external/internal dampers occurring at the same position along the beam axis, modeling external damping devices and internal damping due to damage or imperfect connections, are considered. The challenge is to handle simultaneous discontinuities of the response, in particular bending-moment/rotation discontinuities at the location of external/internal rotational dampers, shear-force/deflection discontinuities at the location of external/internal translational dampers. Following a generalized function approach, the paper will show that exact closed-form expressions of the frequency response under point/polynomial loads can readily be derived, for any number of dampers. Also, the exact dynamic stiffness matrix and load vector of the beam will be built in a closed analytical form, to be used in a standard assemblage procedure for exact frequency response analysis of frames.

• 한국광학회지
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• 제6권2호
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• pp.101-107
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• 1995

본 연구에서는 CFAP(Combined Filter of Amplitude and Phase)형태의 진폭과 위상이 변조된 Bessel beam의 회절 특성을 조사하기 위해 무수차 광학계와 구면수차가 포함된 광학계 각각에 대한 defocus에 따른 강도와 중심 스폿의 반경 변화, 그리고 Optical Transfer Function(OTF) 변화를 Bessel beam의 마디 수를 증가시키면서 계산하였다. Bessel beam은 구면수차를 포함한 광학계에서의 최대 강도 값과 최대 강도 점에서의 OFT값이 무수차 광학계의 경우보다 크게 나타나는 구면수차 보정효과를 보였으며 특히 구면수차가 3.lambda. 포함된 광학계에서의 OTF 값은 Clear aperture의 경우보다 높은 OTF값을 보였다. 또한 defocus에 따른 중심 스폿의 반경은 Airy disk의 반경보다 훨씬 작게 나타나는 영역이 있음을 알 수 있었으며 이러한 결과들은 고집적 반도체 소자 제작을 비롯한 고밀도 광 기록 장치에 이용 가능할 것이다.

• Journal of Computational Design and Engineering
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• 제3권3호
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• pp.215-225
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• 2016

In recent years, the automotive industry has known a remarkable development in order to satisfy the customer requirements. In this paper, we will study one of the components of the automotive which is the twist beam. The study is focused on the multicriteria design of the automotive twist beam undergoing linear elastic deformation (Hooke's law). Indeed, for the design of this automotive part, there are some criteria to be considered as the rigidity (stiffness) and the resistance to fatigue. Those two criteria are known to be conflicting, therefore, our aim is to identify the Pareto front of this problem. To do this, we used a Normal Boundary Intersection (NBI) algorithm coupling with a radial basis function (RBF) metamodel in order to reduce the high calculation time needed for solving the multicriteria design problem. Otherwise, we used the free form deformation (FFD) technique for the generation of the 3D shapes of the automotive part studied during the optimization process.

• 대한기계학회논문집
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• 제18권11호
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• pp.2944-2953
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• 1994

Active range finders using laser beam have been widely used for the factory automation and quality assurance, but they may be unreliable if the object' slope is steep or its surface is specular. The reliability of an active range finder was analyzed for the variation of the reflected laser beam intensity. First, the properties of the object's reflection were modeled by using the bidirectional reflectance-distribution function(BRDF), and then the variation of the laser beam brightness was formulated for the different configuratioin of the object and sensor. The experimental data of the laser beam reflection were obtained for two materials, mild steel and stainless steel. The parameters of the proposed model were obtained by fitting the data of the mild steel to the model and it was found that the results calculated from the proposed model were in good agreement with the experimental data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.286-289
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• 2008

Damping materials are widely used to reduce vibration or noise generation of structures. To understand their damping capability and for use in numerical simulations, their viscoelastic properties should be measured in the frequency range of interest. In this study, experimental setup is proposed to measure materials properties of very compliant polymer materials. The polymer materials used in this study are difficult to form into rod shapes, and typical resonance methods are not applicable. In the proposed measurement setup, the damping materials were modeled as a simple viscoelastic support at one end of the beam. Their properties were measured through analysis of their effects on the wave propagation characteristics of the beam structure.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.573-578
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• 2009

Starting from the rotating beam finite element in which the interpolating shape functions satisfies the governing static homogeneous differential equation of Euler-Bernoulli rotating beams, we derived new shape functions that satisfies the governing differential equation which contains the terms of hub radius and setting angle. The shape functions are rational functions which depend on hub radius, setting angle, rotational speed and element position. Numerical results for uniform and tapered cantilever beams with and without hub radius and setting angle are compared with the available results. It is shown that the present element offers an accurate method for solving the free vibration problems of rotating beam.

• 대한기계학회논문집A
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• 제26권12호
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• pp.2574-2580
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• 2002

In this paper, an experimental verification has been conducted for the frequency response function (FRF)-based structural damage identification method (SDIM) proposed for beam structures. The FRF-based SDIM requires the natural frequencies and mode shapes measured in the intact state and the FRF-data measured in the damaged state. Experiments are conducted for the cantilevered beam specimens with one slot and with three slots. It is shown that the proposed FRF-based SDIM provides damage identification results that agree quite well with true damage state.

• 제어로봇시스템학회논문지
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• 제10권1호
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• pp.30-41
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• 2004

This paper is concerned with the active vibration control of flexible cantilever beam system using electromagnetic farce actuator. The main objective of this paper is to propose the control algorithms and to implement the experimental setups for active vibration control. Dynamic equations of the electromagnetic actuator and the beam are combined to find the transfer function from the electromagnetic actuator to the laser sensor. The final transfer function is determined by considering only the first and second modes, and experiments confirm that this model works well. Several control algorithms are proposed and implemented on the experimental setups to show their efficacy. These include a PID control design, an optimal H$_2$ control design, and a fuzzy PID control design. Effectiveness and performance of the designed controller were verified by both simulation and experiment results.