• Journal of Magnetics
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• v.1 no.1
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• pp.4-8
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• 1996

Employing the LMTO band method, we have studied electronic and magnetic properties of Fe/Si/Fe trilayer in which the z-direction is chosen to be (111) direction of FeSi with B2 phase, We have also determined electronic structure of bulk FeSi, as a reference material. The ground state of FeSi is paramagnetic insulator with a band gap of 0.05 eV. Band structures of Fe/Si/Fe with varying the thickness of the spacer layer reveal that the spacer layer is metallic, and the states along the growth direction do not disperse much reflecting a two-dimensional nature. Magnetic moment of Fe atom in the interfacial layer of Fe/Si/Fe is reduced a lot as compared to the bulk value, suggesting a strong hybridization between Fe and Si states. The geometry of the Fermi surface indicates that the magnetic coupling period of ~8ML (monolayers) in Fe/Si/Fe is explained with a short Fermi wave vector of bcc Si.

• Advances in Computational Design
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• v.1 no.2
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• pp.207-220
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• 2016

The aim of this study is to investigate the effect of stiffened element and edge stiffener in the behaviour and flexural strength of built-up cold-formed steel beams. An experimental and analytical analysis of CFS channel sections in four different geometries is conducted, including simple channel sections, a stiffened channel section with or without edge stiffeners. Nonlinear finite element models are developed using finite element analysis software package ANSYS. The FEA results are verified with the experimental results. Further, the finite element model is used for parametric studies by varying the depth, thickness, and the effect of stiffened element, edge stiffener and their interaction with compression flanges on stiffened built-up cold-formed steel beams with upright edge stiffeners. In addition, the flexural strength predicted by the finite element analysis is compared with the design flexural strength calculated by using the North American Iron and Steel Institute Specifications for cold-formed steel structures (AISI: S100-2007) and suitable suggestion is made.

• Proceedings of the Safety Management and Science Conference
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• 2013.11a
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• pp.547-560
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• 2013

In this study, the air pollutant removal such as sulfur oxides was studied. A combination of the plasma discharge in the reactor by the reaction surface discharge reactor Calcium hydroxides catalytic reactor and air pollutants, hazardous gas SOx, changes in gas concentration, change in frequency, the thickness of the electrode, kinds of electrodes and the addition of simulated composite catalyst composed of a variety of gases, including decomposition experiments were performed by varying the process parameters. The experimental results showed the removal efficiency of 98% in the decomposition of sulfur oxides removal experiment when Calcium hydroxides catalysts and the tungsten(W) electrodes were used. It was increased 3% more than if you do not have the catalytic. If added to methane gas was added the removal efficiency increased decomposition.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.6
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• pp.590-597
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• 2007

The portion of thin plate is expected to increases as to the development of design and fabrication technology. The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates, and in addition internal and external constraints much more influence upon weld-induced deformation of thin plates. This paper is aimed at applying the mechanical tensioning method to fillet weld of thin plates to reduce the weld-induced deformation. For this purpose, fillet welding tests have been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present study, it has been found that the tensioning method is effective on reduction of weld-induced deformation.

• YAKHAK HOEJI
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• v.28 no.3
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• pp.169-177
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• 1984

Release characteristics of salicylic acid from ethylcellulose(EC) films containing varying ratio of dieththylphthalate (DEP) were studied. Mathematical analysis of the release data showed that the release behavior actually conforms with the Higuchi's diffusion-controlled model. The release rate constants(k) were independent from the film thickness and the pH of release medium, but were proportional to the concentration of salicylic acid itself. The logarithm of the release rate constant (log k) increased as the concentration of DEP was increased. In conclusion, hydrophobic plastisizer DEP seemed to be very useful in controlling release rate constant of slightly soluble drugs as like salicylic acid without changing it's release characteristics.

• Transactions of Materials Processing
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• v.3 no.4
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• pp.440-453
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• 1994

The multi-stage deep-drawing processes including normal-drawing, reverse-drawing, and re-drawing are analyzed by use of the rigid-plastic finite element method. Computational results on the punch/die loads and thickness distributions were compared with the experiments of the current drawing processes. Deep-drawing processes of the redesigned shell to improve the specific strength and stiffness were simulated with the numerical method developed. With varying several process parameters such as blank size, corner radii of tools, and clearances, the simulation results showed the improvements in reducing the forming loads. Also forming defects were found during simulation and appropriate blank size could be verified.

• Journal of Welding and Joining
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• v.23 no.4
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• pp.48-52
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• 2005

To estimate welding deformation for large steel structures, either experiment result with small specimen or analysis result of FEM with small numerical model is used. Consequently, it is important to decide the welding length of specimen and numerical model not to have an effect on welding deformation for accurate estimation of whole welding deformation. This study experimentally clarifies the effect of welding length on angular distortion due to welding by varying welding length of specimens, but fixing width and thickness of specimens on V-groove butt welding, fillet welding and bead on plate welding. As a resell the critical welding length on fillet welding and on bead on plate welding is over 500mm and on V-groove butt welding is over 1,000mm.

• Journal of the Korean Institute of Rural Architecture
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• v.16 no.4
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• pp.59-66
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• 2014

This paper deals with vibration of plates with concentrated mass on elastic foundation. The object of investigating natural frequencies of tapered thick plate on pasternak foundation by means of finite element method and providing kinetic design data for mat of building structures. Free vibration analysis that tapered thick plate in this paper. Finite element analysis of rectangular plate is done by use of rectangular finite element with 8-nodes. In order to analysis plate which is supported on pasternak foundation. The Winkler parameter is varied with 10, $10^2$, $10^3$ and the shear foundation parameter is 5, 10. This paper is analyzed varying thickness by taper ratio. The taper ratio is applied as 0.0, 0.25, 0.5, 0.75, 1.0. And the Concentrated Mass is applied as P1, Pc, P2 respectively.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.386-392
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• 1996

Zinc-Borosilicate is used as a side insulator wall to make high breakdown voltage with one Field Limiting Ring in a power p-n junction device in simulation. It is known that surface charge density can be yield at the interface of Zinc-Borosilicate glass / silicon system. When the glass is used as a side insulator wall, surface charge varied potential distribution and breakdown voltage is improved 1090 V under the same structure.The breakdown voltage under varying the surface charge density has a limit value. When the epitaxial thickness is varied, the position of FLR doesn't influence to the breakdown characteristic not only under non punch-through structure but also under punch-through structure. (author). 7 refs., 12 figs., 2 tabs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.688-692
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• 2003

For high voltage operation, a new type of piezoelectric transformer using radial vibration of disk, poled with the same direction was proposed. The piezoelectric ceramics was composed to PZT-PMN-PSN. The diameter and thickness of a disk type piezoelectric transformer were 45［mm］and 4［mm］, respectively The surface ratio of driving electrode and generating electrode of the piezoelectric transformer was 2 : 1. The resonance characteristics of input admittance, step-up voltage ratio and power transmission efficiency of the piezoelectric transformer were measured by varying the load resistance(0.1∼70［kΩ］). As a result, both resonance frequency and step-up voltage ratio increased with increasing load resistance. The step-up voltage ratio was reached more than 60 times under no load resistance. The maximum efficiency of 97% at load resistance of 2kΩ was obtained.