• Transactions of Materials Processing
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• v.27 no.1
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• pp.37-47
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• 2018

In this paper, a double spot welding process, utilizing electric resistance heating dies, is suggested for the spot welding of dissimilar metal plates for drawing and concurrent spot welding. This double welding process has two heating methods for the fusion welding at the interfacial zone between steel and aluminum plates, such as heating method by thermal conduction of electric resistance by welding current induced to heating dies, and heating method by electric resistance between contacted surfaces of two plates by welding current induced to copper electrode. This double welding process has welding variables such as each current induced in heating dies and in copper electrode, outer diameters of heating dies, and edge shape of copper electrode. Experiments for current conditions in welding process should be demanded in order to get successful welding strength. It was known that the welding strength could be reached to the value demanded on industry fields under such welding conditions as heating dies of outer ring dia.12mm contacted on steel plate, as heating dies of outer ring dia. 14mm contacted on aluminum plate, and as copper electrode of dia. 6.0mm, and as 3 times continuous heating method by $1^{st}$ current of 11 kA(9cycle), $2^{nd}$ current 11 kA(60cycle), $3^{rd}$ current 7 kA(60cycle) applied in steel heating dies and copper electrodes, flat edge of copper electrode, for double spot welding process of dissimilar metal plates of steel and aluminum of 1.0 mm thickness.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.9
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• pp.546-551
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• 2000

A micromechanical switch that can be used as a logic gate is described in this paper. This switch consists of fixed input electrodes an output electrode Vcc/GND electrodes and movable plates suspended by crab-leg flexures. for mechanical switching of an electrical signal a parallel plate actuator which comes in contact with output electrode was used. Provided that movable plates are connected to Vcc and a low input voltage(ground signal) is applied to the fixed input electrodes the movable plates are pulled by an electrostatic force between the fixed input electrodes and the movable plates. the proposed micromechanical switch was fabricated by surface micromachining technology with$2\mum$ -thick poly-Si and the measured threshold voltage for ON/OFF switching was 23.5V.

• Journal of Science Education
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• v.46 no.2
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• pp.212-221
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• 2022

In this study, we propose an analytical model to elucidate the formation of electric fields between two parallel conducting plates. Using nine Gaussian surfaces, we investigated the charge redistributions and electric fields formed by parallel conducting plates when two charged plates get close together. The electric charges are redistributed via a new electrostatic equilibrium to create the electric field of each plates. As a result, the electric field start from + electrode plate to - electrode plate via inducing a new electrostatic equilibrium, implying that the application of Gaussian surfaces to only one of the electrodes of parallel-plate capacitors is deserved. The results will help undergraduate students understand the charge redistribution and the electric field formation in parallel-plate capacitors in a reasonable manner.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.407-418
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• 2014

As a continuing work of previously conducted standard tension tests, full-scale flexural tests were conducted in this study to assess the structural performance the CJP groove welded joints connecting thick HSA800 plates. Two welding electrodes were available at the time of this experimental research; one was GMAW-based electrode A and the other FCAW-based electrode B. Three full-scale box-type beam specimens with single bevel- and V-groove CJP welded joints were fabricated from 60mm and 25mm thick HSA800 plates according to the AWS-prequalified groove welded joint details. In designing the specimens, all possible limit states like local and lateral torsional buckling were carefully controlled in order to induce flexural plastic yielding or eventual joint fracture. All the CJP joints made by both welding electrodes showed satisfactory performance and were able to transfer the tensile flange forces higher than that corresponding to the measured tensile strength of HSA800 flange plates. However, it should be noted that, during fabrication, serious concerns about the welding efficiency and workability of the GMAW-based electrode were raised by a certified welder. The fracture occurred at the unbeveled (or vertical) interface between the weldment and the base metal when the GMAW-based electrode was used in the single-bevel joint, implying the possibility of insufficient melting. Thus, the FCAW-based electrode B is again recommended as the choice of welding electrode for HSA800 plates. The limited test data of this study implies that the V-groove CJP joint should be used in favor of the single bevel CJP joint, if possible.

• Transactions of Materials Processing
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• v.21 no.6
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• pp.341-347
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• 2012

The metallic bipolar plates of the molten carbonate fuel cell(MCFC) are composed of shielded slot plates and a center-plate. The shielded slot plates support the center-plate and the membrane electrode assembly. Compressive forces are applied to the shielded slot plate in order to increase the contact area between shielded slot plates and the membrane electrode assembly (MEA). In the design of the shielded slot plate, it is necessary to predict the mechanical behavior of the shielded slot plate. The shielded slot plates are manufactured by a three-stage forming process consisting of slitting, preforming and the final forming process. The mechanical behavior of the shielded slot plate is largely affected by the forming process. In this study, the simulation of the three-stage forming process was used to predict the mechanical behavior of the shielded slot plate. The present simulation approach showed good agreements with the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.9
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• pp.446-451
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• 2006

The output voltage value of AC high voltage source has been usually measured by employing the high voltage divider of inductive or capacitive type. In the study, we have developed a new method for measuring the output voltage up to 60kV using parallel plates electrode and electric field sensor, which are constructed by home-made. Unlikely the conventional method using a high voltage divider, this developed method makes it possible to extend the range of output voltage from known low voltage measurement to high voltage measurement. From the linearity measured between electric field and applied voltage in the output voltage range of 1kV-30kV, the output voltage value up to 60kV can be obtained by the electric field measurement using the electric field sensor. The output voltage value obtained using the method is consistent with that obtained using high voltage divider within corresponding uncertainties.

• Transactions of Materials Processing
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• v.23 no.5
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• pp.282-288
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• 2014

It is difficult to control welding variables during spot welding of non-ferrous metals like aluminum because of the low electrical resistance of the material. It has been suggested that a solid state welding process such as friction stir spot welding or extru-spot welding can be used to spot weld aluminum plates. In the extru-spot welding, there is a need to increase the weld strength by improving the shape of the welding die. The current study shows that the weld strength for an extru-spot welding can be increased by using a pin placed on the inside of the upper electrode in the welding die. In the current study, the deformed shape of the insert rivet and the stress distribution in the welding zone were analyzed by simulation. Extru-rivet spot welding experiments were performed by changing the height of pin on the inside of the upper electrode. From the experimental result, it is shown that the weld strength for an extru-rivet spot welding can be increased by adjusting the height of the pin. The optimal shape of the deformed rivet after the extru-rivet spot welding can be observed from the simulation results. The deformed shape of the insert rivet can also be controlled by the height of pin.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.543-546
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• 2001

So far, the design methods of quartz crystal resonator have been developed. Recently, as the electronic package and semiconductor modules become smaller, the need to minimize the sizes of crystal components grows larger. but Minimizing crystal plate sizes has limitations because its temperature-frequency characteristics is worse and unwanted resonances occur. so appropriate design of electrode size and crystal plates is necessary. In this palter, Two-dimensional governing equations for electroded piezoelectric crystal plates with general symmetry have been solved from deduced equations from three-dimensional equations of linear piezoelectricity in most cases. In practice, electroded piezoelectric crystal plates have three-dimensional geometry, so simplified 2-dimensional equations and 2-D modeling are insufficient for explaining its resonance modes and characteristics. So, three-dimensional FEM(finite element method) analysis is done and its effectiveness is verified from analyzing practical crystal resonator model.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.830-837
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• 2013

The purposes of this research are to know the dust removal efficiency according to the changes of gab between positive and negative plates in dust removal chamber. The experiments for dust removal efficiencies were conducted with changing the electrode-plate gab from 2 cm to 1 cm while the electric pressure, influent flow, and linear velocity were kept 5 kV, 80 L/min, and 6 cm/sec, respectively. From the experimental results of the electrode-plate gab of 2 cm, dust removal efficiencies were decreased to as low as about 50%. Attached dust on the surface of electrodes was released due to a reverse electric charge of dust. From the experimental results of the electrode-plate gab of 1 cm, dust removal efficiencies were increased to as high as about 80% due to the dust attachment velocity to the electrodes to be far more fast than influent linear velocity. Finally, to protect a attached dust from occurring a reverse electric charge it is needed to install the non-conductor between positive and negative electrodes and also to remove air humidity.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.123-128
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• 2016

In manufacturing processing of a secondary battery, the visual inspection system is studied and developed to check the surface defects of the electrode plates. It consists of two parts, one is the hardware control and the other software implementation. The former is made up to the system configuration and the design of the optical system, the illuminations and the controllers. The latter is the detection algorithms of the surface defects. This system achieves the quality improvement of the electrode process and the price competitiveness. By using the proposed defects detection algorithms this system demonstrates the high reliability of spot, line, manhole, extraneous substance, scratch, and crater defect of a electrode plate surface.