• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.496-504
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• 2005

The thermal and mechanical properties of an electro-slag cast steel of a similar chemical composition with an AISI-6F2 steel are investigated and compared with a forged AISI-6F2 steel. AISI-6F2 is a hot-working tool steel. Electro-slag casting (ESC) is a method of producing ingots in a water-cooled metal mold by the heat generated in an electrically conductive slag when current passes through a consumable electrode. The ESC method provides the possibility of producing material for the high quality hot-working tools and ingots directly into a desirable shape. In the present study, the thermal and mechanical properties of yield strength, tensile strength, hardness, impact toughness, wear resistance, thermal fatigue resistance, and thermal shock resistance for electro-slag cast and forged steel are experimentally measured for both annealed and quenched and tempered heat treatment conditions. It has been found that the electro-slag cast steel has comparable thermal and mechanical properties to the forged steel.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.04a
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• pp.73-87
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• 1996

The outer-most electrons of metal atoms and the remining valence electrons of any molecular atoms make three dimensional crystallizing $\pi$-bondings. The electrons on the $\pi$-bonding orbital rotate clockwise or counter-clockwise and they then make electro-magnetic waves between atoms on the orbital because electron move between plus charged ions. The three dimensional crystallizing $\pi$-bonding orbitals are quantum-mechanically modeled by a cyclic Kronig-Penny Model and energy band structures are analyzed with their potential barrier thickness. The waves generated between plus charged ions are the particular $\pi$-far infrared rays, which have dual properties between material and electro-magnetic waves and can be measured not by modern electro-magnetic tester but biosensor such as finger's force tester. Because the $\pi$-rays can be modulated with electro-magnetic waves it can be applied for harmful electro-magnetic wave killers. Because the $\pi$-rays make new three dimensional crystallizing $\pi$-bonding orbitals in the material the food and drink can be transformed into a helpful physical constitutional property for human health. Distinction between crystalline and amorphous metals is possible because very strong crystalline $\pi$-bonding orbitals can not easily be transformed into another. The $\pi$-rays can also be applied for biofunctional diagnostics and therapy. Gravitational field is one of the electro-magnetic fields. And also magnetic field and gravitational force field make charge's movement. ($\times$ = q, : magnetic field, : force field, q: plus charge, : velocity field)

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.3
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• pp.246-254
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• 2022

Localized heat can be generated using electrically conductive word-lines built into a 3D NAND flash memory string. The heat anneals the gate dielectric layer and improves the endurance and retention characteristics of memory cells. However, even though the electro-thermal annealing can improve the memory operation, studies to investigate material failures resulting from electro-thermal stress have not been reported yet. In this context, this paper investigated how applying electro-thermal annealing of 3D NAND affected mechanical stability. Hot-spots, which are expected to be mechanically damaged during the electro-thermal annealing, can be determined based on understanding material characteristics such as thermal expansion, thermal conductivity, and electrical conductivity. Finally, several guidelines for improving mechanical stability are provided in terms of bias configuration as well as alternative materials.

• Journal of Welding and Joining
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• v.22 no.6
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• pp.50-56
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• 2004

MlAB(magnetically impelled arc butt) welding is a sort of pressure welding method by melting two pipe sections with high speed rotating arc and upsetting two pipes in the axial direction. The electro-magnetic force, the driving force of the arc rotation, is generated by interaction of arc current and magnetic field induced from the magnetic flux generator in the welding system. In this study, an openable coil system for the generation of magnetic flux and a 3-dimensional numerical model for analyzing the electro-magnetic field were proposed. Through the fundamental numerical analyses, a magnetic concentrator was adopted for smoothing the magnetic flux density distribution in the circumferential direction. And then a series of numerical analysis were performed for investigating the effect of system parameters on the magnetic flux density distribution in the interested welding area.. Numerical quantitative analyses showed that magnetic flux density distribution generated from the proposed coil system is mainly dependent on the exciting current in the coil and the position of coil or concentrator from the pipe outer surface. And the gap between pipe ends and arc current are also considered as important factors on arc rotating behavior.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.334-343
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• 2003

The discharge gap clearly is to order and to promote the improvement of processing feature of die-sinking electro discharge machining(EDM). If creation carbon, which generated by Pyrolysis of EDM oil and processing pace power which is generated in between an electrode and a workpiece, are overproduced, they will lower the processing speed and roughness of the surface. Therefore, it is gone through an experiment and the flow analysis of EDM oil in order to improve the treatment of processing chips, which is an important problem by contriving a new flushing method. The condition of an electric discharge is not considered to be a progressing of processing. It is assumed that the flow of processing fluid is equal to the flow of processing chip, which is remaining in the discharge gap, and thus, analyzing then comparing with the data of the experiment and investigate its correlation.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.272-277
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• 2005

The discharge gap clearly is to order and to promote the improvement of processing feature of die-sinking electro discharge machining(EDM). If creation carbon, which generated by pyrolysis of EDM oil and processing pace power which is generated in between an electrode and a workpiece, are overproduced, they will lower the processing speed and roughness of the surface. Therefore, it is gone through the .flow analysis of EDM oil in order to improve the treatment of processing chips, which is an important problem by contriving a new flushing method. The condition of an electric discharge is not considered to be a progressing of processing. It is assumed that the flow of processing fluid is equal to the flow of processing chip, which is remaining in the discharge gap, and analyzing its correlation.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.663-669
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• 2002

Electro-flotation (EF) has shown advantages, such as a high removal efficiency and easy control of bubble generation, over dissolved air flotation. However, the fundamental characteristics of the process have not been investigated in detail. According to recent modeling results from trajectory analysis, the size of the bubble is one of the most important factors that affect the efficiency of collision between bubble and particle. In this paper, the size characteristics of bubbles generated from EF under various conditions are measured using a new method for bubble size measurement, the Particle Counter Method (PCM). The size of the generated bubbles was found to be constant with respect to applied voltage but to vary with the electrode materials. These results and their implications are discussed.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.10-13
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• 2021

The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. Lorentz force was generated downward and the reaction force to the plastics was upward. The plastic used in the experiment was polystyrene with a diameter of 6 mm, and the density was 1.07 g/cm³. The polystyrene sphere levitated at the current density of 0.83 A/cm² and the external field of 0.87T. The particle trajectory calculation was also made to design separation system using superconducting magnet.

• Coupled systems mechanics
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• v.1 no.2
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• pp.205-217
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• 2012

A smart beam made of magneto-electro-elastic (MEE) material having piezoelectric phase and piezomagnetic phase, shows the coupling between magnetic, electric, thermal and mechanical under thermal environment. Product properties such as pyroelectric and pyromagnetic are generated in this MEE material under thermal environment. Recently studies have been published on the product properties (pyroelectric and pyromagnetic) for magneto-electro-thermo-elastic smart composite. Hence, the magneto-electro-elastic beam with different volume fractions, investigated under uniform temperature rise is the main aim of this paper, to study the influence of product properties on clamped-free boundary condition, using finite element procedures. The finite element beam is modeled using eight node 3D brick element with five nodal degrees of freedom viz. displacements in the x, y and z directions and electric and magnetic potentials. It is found that a significant increase in electric potential observed at volume fraction of $BaTiO_3$, $v_f$ = 0.2 due to pyroelectric effect. In-contrast, the displacements and stresses are not much affected.

• Resources Recycling
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• v.17 no.6
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• pp.24-33
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• 2008

The leaching of Cu from waste PCBs was investigated with electro-generated chlorine as an oxidant. The leaching experiments were carried out according to the design of experiments to analyze quantitatively the effect of parameters on copper leaching. From the analysis of variance (ANOVA) it was suggested that the effective parameters were current density, temperature, concentration of HCl, and the interaction between the concentration of HCl and temperature. Especially, the effect of current density was analyzed to contribute to the interpretation of result for copper leaching up to 95.7%. A multiple regression model obtained from the analysis of effective parameters explained 99% of leaching results. From the model equation, it was found that the effect of HCl concentration on copper leaching increased with temperature.