• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.135-136
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• 1998

By the ion bombardment the original discrete layered structure is damaged and a uniformly mixed layer is formed by the intermixing of the films. Immediately after this dynamic cascade mixing a structure of this mixed layer is likely to be a mixture of randomly distributed atoms. Subsequently the mixed layered structure becomes a non-equilibrium structure such as the metastable pphase because the kinetic energies of the incident ions rappidly dissippate and host atoms within the collision cascade region are quenched from a highly energetic state. The formation of the metastable transition metal alloys using ion-beam-mixing has been extensively studied for many years because of their sppecific ppropperties that differ from those of bulk materials. in ion-beam-mixing the alloy or comppound is formed due to the atomic interaction between different sppecies during ion bombardment. in this study the metastable pphase formed by ion-beam-mixing pprocess is comppared with equilibrium one by arc-melting method by GXRD and XAS. Therfore we studied the fundamental characteristics of charge redistribution uppon alloying and formation of intermetallic comppounds. The multi-layer films were depposited on a wet-oxidized Si(100) substrate by sequential electron beam evapporation at a ppressure of less than 5$\times$10-7 Torr during depposition. These compprise 4 ppairs of Co and ppt layers where thicknesses of each layer were varied in order to change the alloy compposition.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.103-103
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• 2003

A newly developed contact angle measurement instrument by laser beam projection allows for rapid and direct determination of contact angles. From the result of comparative experiment and questionnaire, the laser contact angle.

• Progress in Medical Physics
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• v.28 no.3
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• pp.129-133
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• 2017

The machine log files recorded by a scanning control unit in proton beam therapy system have been studied to be used as a quality assurance method of scanning beam deliveries. The accuracy of the data in the log files have been evaluated with a standard calibration beam scan pattern. The proton beam scan pattern has been delivered on a gafchromic film located at the isocenter plane of the proton beam treatment nozzle and found to agree within ${\pm}1.0mm$. The machine data accumulated for the scanning beam proton therapy of five different cases have been analyzed using a statistical method to estimate any systematic error in the data. The high-precision scanning beam log files in line scanning proton therapy system have been validated to be used for off-line scanning beam monitoring and thus as a patient-specific quality assurance method. The use of the machine log files for patient-specific quality assurance would simplify the quality assurance procedure with accurate scanning beam data.

• Structural Engineering and Mechanics
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• v.21 no.1
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• pp.19-33
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• 2005

An improved shear deformable thin-walled curved beam theory to overcome the drawback of currently available beam theories is newly proposed for the spatially coupled free vibration and elastic analysis. For this, the displacement field considering the shear deformation effects is presented by introducing displacement parameters defined at the centroid and shear center axes. Next the elastic strain and kinetic energies considering the shear effects due to the shear forces and the restrained warping torsion are rigorously derived. Then the equilibrium equations are consistently derived for curved beams with non-symmetric thin-walled sections. It should be noticed that this formulation can be easily reduced to the warping-free beam theory by simply putting the sectional properties associated with warping to zero for curved beams with L- or T-shaped sections. Finally in order to illustrate the validity and the accuracy of this study, finite element solutions using the isoparametric curved beam elements are presented and compared with those in available references and ABAQUS's shell elements.

• Journal of Korean Society of Steel Construction
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• v.13 no.1
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• pp.91-100
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• 2001

This paper is to analyze the stability of Timoshenko beam-column on Pasternak foundation, with the extensional and the rotational spring at center point of span by Finite Element Method. To verify this Finite Element Method, the results by the proposed method are compared with the existing solutionsof Timoshenko beam-column without the extensional and the rotational spring and the shear foundation. The dynamic stability regions are decided by the dynamic stability analysis of Timoshenko beam-column on Pasternak foundation with the extensional and the rotation spring at center point of span.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.90-95
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• 2001

f-$\theta$len is one of the important parts in Laser Scanning Unit because it affects on the optical performance of Laser Scanning Unit dominantly. It is necessary to find out the relationship between the surface profile error of f-$\theta$lens and the beam profile focusing on the Organic Photo Conductive drum in order to analysis the beam profile problems such as appearance of side lobe and expansion of center lobe. In this research, a simulation process which relates the surface profile characteristics to the beam profile has been developed by CODE V. The simulated beam profile also have been compared with the measurement results.

• Journal of Korean Society of Steel Construction
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• v.27 no.1
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• pp.63-75
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• 2015

In this study, Composite beam flexural capacity was investigated experimentally using angle as a shear connector. The main experimental parameters are the size and the spacing of the angle and the overall behavior of before and after composite. Also, the composite beam bending performance when it used with hollow PC slab and the general RC slab was compared. When determining that it synthetically, the flexural capacity of the composite beam with angle shear connector estimated 25% to 55% more strength than the nominal strength. Effects of strength parameters of composite beam by angles shear connector are size and spacing of the angle. As expected, the larger and the narrower spacing of the angles, the more strength the composite beam have. In addition, the performance of the composite beam with a hollow slab was well demonstrated by the test.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.262-262
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• 2012

A multi-purpose cyclotron, MC50 has been operated to provide multi-ions of proton, deuteron and alpha at Korea Institute of Radiological and Medical Sciences (KIRAMS). Neutron is also produced through the (p,n) nuclear process with a Be target. However, a wide spectrum of current of ions is requested by beam users for carrying their various application fields. Therefore a simulation study is requested on the design of an axial injection system for high current proton and alpha beam extraction for radio-isotope productions and scientific researches. The purpose of this study is seeking a relatively simple method for the MC50 having higher alpha beam capability and also improving proton and deuteron beams currently used. We are considering two possibilities to improve the internal ion source and to install a new external axial injection system. The external injection system will be consisted of an Einzel lens, a steering magnet, a buncher, and a glazer lens placed in front of an inflector, which is located at the center of the main magnet.

• Bulletin of the Korean Chemical Society
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• v.35 no.10
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• pp.2969-2973
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• 2014

A new process to fabricate a composite LSCF-Ag cathode material for SOFCs by electron beam (e-beam) irradiation process has been suggested for operation under intermediate temperature range of $600-700^{\circ}C$. A composite LSCF-Ag cathode with uniformly coated Ag nanoparticles on the surface of the LSCF material was prepared by a facile e-beam irradiation method at room temperature. The morphology of the composite LSCF-Ag material was analyzed using a TEM, FE-SEM, and EDS. The prepared composite LSCF-Ag material can play a significant role in increasing the electro-catalytic activities and reducing the operating temperature of SOFCs. The performance of a tubular single cell prepared using the composite LSCF-Ag cathode, YSZ electrolyte and a Ni/YSZ anode was evaluated at reduced operating temperature of $600-700^{\circ}C$. The micro-structure and chemical composition of the single cell were investigated using a FE-SEM and EDS.

• Steel and Composite Structures
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• v.45 no.4
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• pp.555-562
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• 2022

Improving the mechanical properties of concrete in the construction industry in order to increase resistance to dynamic and static loads is one of the essential topics for researchers. In this work, vibration analysis of elastic nanocomposite beams reinforced by nanoparticles based on mathematical model is presented. For modelling of the strucuture, sinusoidal shear deformation beam theory (SSDBT) is utilized. Mori-anak model model is utilized for obtaining the effective properties of the strucuture including agglomeration influences. Utilizing the energy method and Hamilton's principal, the motion equations are calculated. The frequency of the elastic nanocomposite beam is obtanied by analytical method. The aim of this work is investigating the effects of nanoparticles volume percent and agglomeration, length and thickness of the beam on the frequency of the structure. The results show that the with enhancing the nanoparticles volume percent, the frequency is increased. In addition, the water absorption of the concrete is presented in this article.