• Title/Summary/Keyword: Multi-Function Electrode

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Micro Electrochemical Machining Using a Multi-Function Electrode (복합기능 전극을 이용한 미세 전해가공)

  • Shin, Hong-Shik;Kim, Bo-Hyun;Kim, Gyu-Man;Chung, Do-Kwan;Chu, Chong-Nam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.5
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    • pp.496-501
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    • 2009
  • In micro electrochemical machining(micro-ECM), it is important to measure and control the potential of a tool electrode and a workpiece electrode because electrochemical reaction rate depends on the potential of the electrodes. When the electrode potential was measured against a reference electrode, the error of measured electrode potential could be minimized by proper tool electrode design. In this paper, multi-function electrodes consisting of a tool electrode and a reference electrode was fabricated by micro fabrication techniques. The machining conditions in micro-ECM using multi-function electrodes, such as pulse voltage parameters and electrode potential, were investigated.

Electrode Shape Design for Multi-Mode Sensors Using Genetic Algorithm (유전 알고리즘을 이용한 다중모드 감지기를 위한 전극의 형상 설계)

  • Park, Chul-Hue;Lee, Ki-Moon;Park, Hyun-Chul
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.637-642
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    • 2004
  • This paper presents a new shape design method for the multi-mode sensor that can detect selected multiple modes for the active vibration control of mechanical structures. The structure used for this study is an isotropic cantilever beam type with a PVDF(polyvinylidene fluoride) which is bonded onto the structure as a sensor. Characteristic behaviors of the sensor are related with the electrode shapes of PVDF. The shape optimization problem is solved by defining a new multi-objective function and using the genetic algorithm. Resulting electrode shape functions have good performances to detect the multiple vibration modes. The results of analytical simulations are compared with those of experiment works. The results agree well each other. Hence, the obtained experimental results give evidence for the validity of the presented theoretical analysis of the electrode shape design problem.

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Design of Modal Transducer in 2D Structure Using Multi-Layered PVDF Films Based on Electrode Pattern Optimization (다층 압전 필름의 전극 패턴 최적화를 통한 2차원 구조물에서의 모달 변환기 구현)

  • 유정규;김지철;김승조
    • Journal of KSNVE
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    • v.8 no.4
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    • pp.632-642
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    • 1998
  • A method based on finite element discretization is developed for optimizing the polarization profile of PVDF film to create the modal transducer for specific modes. Using this concept, one can design the modal transducer in two-dimensional structure having arbitrary geometry and boundary conditions. As a practical means for implementing this polarization profile without repoling the PVDF film the polarization profile is approximated by optimizing electrode patterns, lamination angles, and poling directions of the multi-layered PVDF transducer. This corresponds to the approximation of a continuous function using discrete values. The electrode pattern of each PVDF layer is optimized by deciding the electrode of each finite element to be used or not. Genetic algorithm, suitable for discrete problems, is used as an optimization scheme. For the optimization of each layers lamination angle, the continuous lamination angle is encoded into discrete value using binary 5 bit string. For the experimental demonstration, a modal sensor for first and second modes of cantilevered composite plate is designed using two layers of PVDF films. The actuator is designed based on the criterion of minimizing the system energy in the control modes under a given initial condition. Experimental results show that the signals from residual modes are successfully reduced using the optimized multi-layered PVDF sensor. Using discrete LQG control law, the modal peaks of first and second modes are reduced in the amount of 12 dB and 4 dB, resepctively.

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Electrode Shape Optimization of Piezo Sensors Using Genetic Algorithm (유전 알고리듬을 이용한 압전센서의 전극형상 최적화)

  • Lee Ki-Moon;Park Hyun-Chul;Park Chul-Hue
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.6 s.249
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    • pp.698-704
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    • 2006
  • This paper presents an electrode shape design method for the multi-mode sensors that could deteict the selected structural multiple modes. The structure used for this study is an isotropic cantilever beam type with a PVDF (polyvinylidene fluoride) which is bonded onto the structure as a sensor. The shape optimization problem is solved by using Genetic Algorithm (GA) with an appropriate objective function. The performance of analytical optimal shape sensor is compared with that of experimental work. The results show that the, obtained electrode shape sensors have good performance to detect the multiple vibration modes simultaneously.

Development of Multi-Array Electrode and Programmable Multi-channel Electrical Stimulator for Firing Trigger Point of Myofascial Pain Syndrome (근막통증증후군의 통증유발점 치료를 위한 멀티어레이 전극과 프로그램 가능한 다채널 전기자극기 개발)

  • Kim, SooHong;Kim, SooSung;Jeon, GyeRok
    • Journal of Biomedical Engineering Research
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    • v.36 no.5
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    • pp.221-227
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    • 2015
  • In this study, Multi-Array Electrodes (MAE) and Programmable Multi-channel Electrical Stimulator (PMES) were implemented for firing Trigger Points (TPs) of the patient with Myofascial Pain Syndrome (MPS). MAE has 25 Ag/AgCl electrodes arranged in the form of array ($5{\times}5$) fabricated with flexible pad, which are applicable to be easy-attached to curved specific region of the human body. PMES consisted of 25 channels. Each channel was to generate various electric stimulus patterns (ESPs) by changing the mono-phasic or bi-phasic of ESP, On/Off duration of ESP, the interval between ESP, and amplitude of ESP. PMES hardware was composed of Host PC, Stimulation Pattern Editing Program (SPEP), and Multi-channel Electrical Stimulator (MES). Experiments were performed using MAE and PMES as the following. First experiment was performed to evaluate the function for each channel of Sub- Micro Controller Unit (SMCU) in MES. Second experiment was conducted on whether ESP applied from each channel of SMCU in PMES was focused to the electrode set to the ground, after applying ESP being output from each channel of SMCU in PMES to MAE.

An Application of Fuzzy Logic with Desirability Functions to Multi-response Optimization in the Taguchi Method

  • Kim Seong-Jun
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.5 no.3
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    • pp.183-188
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    • 2005
  • Although it is widely used to find an optimum setting of manufacturing process parameters in a variety of engineering fields, the Taguchi method has a difficulty in dealing with multi-response situations in which several response variables should be considered at the same time. For example, electrode wear, surface roughness, and material removal rate are important process response variables in an electrical discharge machining (EDM) process. A simultaneous optimization should be accomplished. Many researches from various disciplines have been conducted for such multi-response optimizations. One of them is a fuzzy logic approach presented by Lin et al. [1]. They showed that two response characteristics are converted into a single performance index based upon fuzzy logic. However, it is pointed out that information regarding relative importance of response variables is not considered in that method. In order to overcome this problem, a desirability function can be adopted, which frequently appears in the statistical literature. In this paper, we propose a novel approach for the multi-response optimization by incorporating fuzzy logic into desirability function. The present method is illustrated by an EDM data of Lin and Lin [2].

A Carbon Nanotube Sample for the Fabrication of Nanotweezer (나노트위져 제작을 위한 탄소나노튜브 샘플)

  • Choi, Jai-Seong;Lee, Jun-Sok;Kang, Gyung-Soo;Kwak, Yoon-Keun;Kim, Soo-Hyun
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.997-1000
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    • 2004
  • This paper introduces our basic research about a carbon nanotube(CNT) sample for the fabrication of nanotweezer. We have made the nanotweezer through the physical adhesion of multi-walled carbon nanotubes(MWCNTs) on two sharp tungsten tips. Thereby we needed the CNT sample which is proper to this fabrication process. And we applied the dielectrophoretic methods to the fabrication of the CNT sample. During the basic experiment, we used a sharp edged electrode and a flat electrode as electrodes for dielectrophoresis and just a function generator as a voltage source for the generation of electric field.

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Design of Inverter for Driving the Multi-lamp using an Piezoelectric Transformers (압전 변압기를 이용한 멀티 램프 구동용 인버터 설계)

  • Cho Sung-Koo;Lim Young-Cheol;Yang Seung-Hak
    • The Transactions of the Korean Institute of Power Electronics
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    • v.10 no.2
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    • pp.130-137
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    • 2005
  • LCD needs a backlight that is a light source as a photodetector that has a light modulation function and CCFL is used usually. Inverter that composes using existent winding transformer operates multi lamps, however, this efficiency falls by losses of core or winding and volume or weight increases or there is danger of fire by overheating. In order to solve these problems, a multi lamp driving Inverter using PT is composed according to the design guideline in this paper. We conformed whether the multi lamp drive method using EEFL that a current burden is less in applicable to piezoelectric inverter, and used the method that connect two piezoelectric transformers by parallel to an inverter.

Nano-scale Design of electrode materials for lithium rechargeable batteries

  • Gang, Gi-Seok
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.72-72
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    • 2012
  • Lithium rechargeable batteries have been widely used as key power sources for portable devices for the last couple of decades. Their high energy density and power have allowed the proliferation of ever more complex portable devices such as cellular phones, laptops and PDA's. For larger scale applications, such as batteries in plug-in hybrid electric vehicles (PHEV) or power tools, higher standards of the battery, especially in term of the rate (power) capability and energy density, are required. In PHEV, the materials in the rechargeable battery must be able to charge and discharge (power capability) with sufficient speed to take advantage of regenerative braking and give the desirable power to accelerate the car. The driving mileage of the electric car is simply a function of the energy density of the batteries. Since the successful launch of recent Ni-MH (Nickel Metal Hydride)-based HEVs (Hybrid Electric Vehicles) in the market, there has been intense demand for the high power-capable Li battery with higher energy density and reduced cost to make HEV vehicles more efficient and reduce emissions. However, current Li rechargeable battery technology has to improve significantly to meet the requirements for HEV applications not to mention PHEV. In an effort to design and develop an advanced electrode material with high power and energy for Li rechargeable batteries, we approached to this in two different length scales - Atomic and Nano engineering of materials. In the atomic design of electrode materials, we have combined theoretical investigation using ab initio calculations with experimental realization. Based on fundamental understanding on Li diffusion, polaronic conduction, operating potential, electronic structure and atomic bonding nature of electrode materials by theoretical calculations, we could identify and define the problems of existing electrode materials, suggest possible strategy and experimentally improve the electrochemical property. This approach often leads to a design of completely new compounds with new crystal structures. In this seminar, I will talk about two examples of electrode material study under this approach; $LiNi_{0.5}Mn_{0.5}O_2$ based layered materials and olivine based multi-component systems. In the other scale of approach; nano engineering; the morphology of electrode materials are controlled in nano scales to explore new electrochemical properties arising from the limited length scales and nano scale electrode architecture. Power, energy and cycle stability are demonstrated to be sensitively affected by electrode architecture in nano scales. This part of story will be only given summarized in the talk.

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Synthesis of microporous carbons containing multi-functional groups and their electrochemical performance (다중 기능성 그룹을 포함하는 마이크로포어 탄소의 합성 및 전기화학적 특성)

  • Kim, Ki-Seok;Park, Soo-Jin
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.94.2-94.2
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    • 2011
  • In this work, multi-functional groups, i.e., nitrogen and oxygen, contained microporous carbons (MF-MCs) were prepared by the one step carbonization of the poly(vinylidene chloride-co-acrylonitrile-co-methyl methacryalte) (PVDC-AN-MMA) without activation. The electrochemical performance of MF-MCs was investigated as a function of carbonization temperature. It was found that MF-MCs had a high specific surface area over $800m^2/g$ without additional activation, resulting from the micropore's formation by the release of chlorine groups. In addition, although functional groups decreased, specific surface area was increased with increasing carbonization temperature, leading to the enhanced electrochemical performance. The pore size of the carbon distributed mainly in small micropore of 1.5 to 2 nm, which was idal for aqueous electrolyte. Indeed, the unique microstructure features, i.e. high specific surface area and optimized pore size provided high energy storage capability of MF-MCs. These results indicated that the microporous features of MF-MCs lead to feasible electron transfer during charge/discharge duration and the presence of nitrogen and oxygen groups on the MF-MCs electrode led to a pseudocapacitive reaction.

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