• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.398-398
• /
• 2016

A triboelectric generator uses the principles of static electrification and electrostatic induction to convert mechanical energy into useful electrical energy. In this work we study a single degree of freedom (SDOF) vibration type triboelectric generator that is initiated by a vibrating source at its base. The system is modeled in Abaqus and the design parameters are systematically explored by their effect on the output. The relationships between the parameters: input force, input frequency, mass, spring stiffness and gap between the plates, are analyzed. Finally, based on initial experiments, and simulation results, a design methodology is formulated. The methodology will provide guidance for application specific design of reliable and effective vibration type triboelectric generators.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2002년도 추계학술대회논문집
• /
• pp.346-351
• /
• 2002

Noise of the VVVF inverter and DC/DC converter, which are the most dominant noise sources of maglev train at low speed, is studied, The coils inside inverter and converter are excited by electro-magnetic forces, which results in core vibration and generations of the noise. It is found that the spectra of the noise show many harmonics, where there exist several different fundamental frequencies. Some noise reducing techniques are known for the transformer noise such as changing stiffness and using different core materials, which make less electrostatic responses, and consequently less noise. In this study, it is shown that the most effective and feasible noise reducing method is to increase the switching frequencies of the inverter and converter, where peaks in higher frequency are significantly reduced.

• 한국안전학회지
• /
• 제8권3호
• /
• pp.34-43
• /
• 1993

This paper presents a study on the characteristics and safety criteria for human body in ELF (Extremely Low Frequency : 50-60Hz) electric and magnetic fields. Many researches for ELF electric and magnetic fields, which are developed in the past, are studied and analyzed In this paper. In order to estabilish the safety criteria for human body in the field, the field intensity, induced current and voltage are calculated by the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation. The method is applied to the 345 KV transmission line system In operation and 765 KV system under consideration. According to the results, the maximum value of field intensity, 6.8627KV/m, is evaluated at the location which is 14m away from transmission line. As the safety criteria value by the abroad researches asserting that the human can detect the Induced current in 6KV/m and above, 5KV/m and 7KV/m are recommended at residence area and nonresidence area, respectively.

• Journal of Power Electronics
• /
• 제10권3호
• /
• pp.277-284
• /
• 2010

This paper presents a novel hybrid carrier based space vector modulation for cascaded multilevel inverters. The proposed technique inherits the properties of carrier based space vector modulation and the fundamental frequency modulation strategy. The main characteristic of this modulation are the reduction of power loss, and improved harmonic performance. The carrier based space vector modulation algorithm is implemented with a TMS320F2407 digital signal processor. A Xilinx Complex Programmable Logic Device is used to develop the hybrid PWM control algorithm and it is integrated with a digital signal processor for hybrid carrier based space vector PWM generation. The inverter offers less weighted total harmonic distortion and it operates with equal electrostatic and electromagnetic stress among the power devices. The feasibility of the proposed technique is verified by spectral analysis, simulation, and experimental results.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 춘계학술대회논문집
• /
• pp.917-923
• /
• 2001

This paper presents the fabrication and testing results of a dual stage microactuator system for fine positioning of magnetic heads in hard disk drives. An electrostatic rotary microactuator was newly designed and fabricated. The microactuator was integrated into the head gimbal assembly of a disk drive system and its dynamic characteristics were investigated. Experimental results show that natural frequency and voltage gain of the microactuator are 4.3 KHz and 25 nm/V and the dual stage microactuator system achieves the tracking accuracy of 30 nm.

• 소음진동
• /
• 제9권3호
• /
• pp.621-628
• /
• 1999

본 논문에서는 평면 계에서의 전기전하 입자의 기본적인 동특성을 간단한 모델을 이용하여 실험적으로 살펴보았다. 실험에서는 전기전하입자 모델로 4개의 소형구(전도체로 표면을 잘 도포한 탁구공)를 사용하였으며, 측정시 중력효과를 배제하기 위하여 잘 절연된 줄에 매달린 형태를 적용하였다. 실험으로 측정한 평형위치(각도)와 전하입자의 고유동수는 계산된 값과 상당히 근접함을 보인다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 하계학술대회 논문집 A
• /
• pp.103-105
• /
• 1994

A novel structure of a lineal microactuator has been designed and analyzed. The proposed structure can overcome serious problems from which conventional linear microactuators suffer, primarily due to the moving principle that is the repetition of attachment and detachment of the moving part to the fixed part. According to the calculated results, the proposed microactuator can generate force of a few mN and the moving sled of 13 cm/min under the condition of 100 volts and the frequency of 1.4 kHz.

• Coupled systems mechanics
• /
• 제4권3호
• /
• pp.251-262
• /
• 2015

The current paper aims at investigating the nonlinear dynamical behaviour of an electrically actuated microcantilever. The microcantilever is excited by a combination of AC and DC voltages. The nonlinear equation of motion of the microcantilever is obtained by means of force and moment balances. A high-dimensional Galerkin scheme is then applied to reduce the equation of motion to a discrete model. A numerical technique, based on the pseudo-arclength continuation method, is used to solve the discretized model. The electrostatic deflection of the microcantilever and static pull-in instabilities, due to the DC voltage, are analyzed by plotting the so-called DC voltage-deflection curves. At the simultaneous presence of the DC and AC voltages, the nonlinear dynamical behaviour of the microcantilever is analyzed by plotting frequency-response and force-response curves.

• 소성∙가공
• /
• 제11권7호
• /
• pp.575-580
• /
• 2002

To evaluate elastic and micro-failure properties of MEMS materials, the electro-statically operated test devices were designed and fabricated by micro machining technology. The test structures consist or comb drives for loading and suspending beams in testing. From the analysis of beam displacement based on elastic beam theory, elastic modulus and yield strength of Al film were measured. And, by introducing the micro notch and cyclic loading, the micro-failure was Induced and the micro-fracture toughness of Si film was evaluated. Moreover, the cycles to failure were estimated from the degradation of resonant frequency. Finally, the effects of notch on micro failure were discussed.

• Bulletin of the Korean Chemical Society
• /
• 제31권4호
• /
• pp.941-948
• /
• 2010

Ab initio and density functional theory methods have been employed to study all theoretically possible conformers of fluoroacetic acid. Molecular geometries and energetic of cis and trans monomers and cis dimers in gaseous phase have been obtained using HF, B3LYP and MP2 levels of theory, implementing 6-311++G(d,p) basis set. It was found that cis rotamers are more stable. In addition, it was found that in comparison with acetic acid the strength of hydrogen bonding in fluoroacetic acid decreased. The infrared spectrum frequencies and the vibrational frequency shifts are reported. Natural population and atom in molecule analysis performed to predict electrostatic interactions in the cyclic H-bonded complexes and charges. The proton transfer reaction is studied and activation energy is compared with acetic acid proton transfer reaction.