• Korean Journal of Mathematics
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• v.4 no.1
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• pp.51-64
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• 1996

In this paper we investigate the existence of weak solutions of a nonlinear beam equation under Dirichlet boundary condition on the interval $-\frac{\pi}{2}<x<\frac{\pi}{2}$ and periodic condition on the variable $t$, $u_{tt}+u_{xxxx}=p(x,t,u)$. We show that if $p$ satisfies condition $(p_1)-(p_3)$, then the nonlinear beam equation possesses at least one weak solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.221-222
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• 2007

• Journal of Korean Association for Spatial Structures
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• v.20 no.2
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• pp.19-23
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• 2020

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3866-3873
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• 2023

In 4th^-generation storage rings, whether to operate the beam as round or flat is a critical question. A round beam has equal horizontal and vertical emittances, and is an efficient solution to reduce strong intra-beam scattering effects and lengthen the Touschek lifetimes, but a flat beam produces a brighter photon beam than a round beam. To provide both beams concurrently rather than bifurcating the beam time, this paper presents the exploitation of beam dynamics and the cutting-edge fast pulser that supports concurrent operation of round beam and flat beam.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1862-1865
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• 2005

We have a plan to design a controller for electron beam manufacturing system. At first, we designed a controller for SEM. The controller consists of five parts (power source, beam controller, scanning controller, optic controller and main controller). Beam controller supplies pulse wave for generating high voltage and can monitor the status of high voltage instrument through emission current. Optic controller controls focus, spot size and image shift. Main controller transmits variables from operating program to each part and monitors the status of peripheral device.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.760-763
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• 2003

We have investigated the electro-optical characteristics of image sticking in AC PDP. Although Image sticking is one of major factors to determine display quality in AC PDP, so far, it has not being reported why it is occurred and how we can prevent it. In this experiment, we have analyzed the effect of MgO protective layer and phosphor on the image sticking and we have measured the difference of firing voltage, brightness and discharge current between sticking image and normal image in AC PDP. As a result, Phosphor degradation is a more major factor than MgO protective layer and the firing voltage of gas discharge in sticking image is higher than that of normal discharge.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.764-767
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• 2003

We have experimentally investigated the influence of wall charge configurations prior to addressing discharge on dynamic margin in AC plasma display panel. In this experiment, we have analyzed the quantity and polarity of wall charge accumulated on the front and rear dielectrics just prior to the addressing discharge under the conventional driving sequence.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.768-770
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• 2003

In AC PDP, since charges generated by gas discharge are accumulated on the dielectric. The dielectric is a major factor to determine cell capacitance and its memory effect is a play an important role in PDP driving. In this experiment, we have investigated the electro-optical characteristics with dielectric thickness and we have analyzed wall charge and wall voltage by Q-V energy diagram. The dielectric thickness was varied from 20 um to 50 um. As results, according to the dielectric thickness increase,cell capacitance and power consumption is reduced.

• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.23-27
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• 2006

We are studying the application of an adaptive optics system to upgrade the beam quality of a laser. The adaptive optics (AO) system consists of a bimorph deformable mirror, a Shack-Hartmann sensor and a control system. In most AO applications, the beam aperture is considered to be circular. However, in some cases such as laser beams from unstable resonators, the beam apertures are annulus or a holed-rectangle. In this paper, we investigate how well a bimorph deformable mirror of ${\Phi}120\;mm$ clear aperture can compensate phase distortions for three different beam configurations; 1) ${\Phi}120\;mm$ circular aperture, 2) ${\Phi}100\;mm$ annulus aperture with a ${\Phi}20\;mm$ hole and 3) $70\;mm{\times}70\;mm$ square aperture with a hole of $30\;mm{\times}30\;mm$. This study concludes that the bimorph mirror, which might be considered as a modal controller, can compensate tilt, defocus, coma and astigmatism, and spherical aberration for all three beams.

• Transactions of Materials Processing
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• v.24 no.1
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• pp.13-19
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• 2015

For an accurate analysis of hot stamping, a coupled simulation with different aspects of the process(i.e. mechanical, thermal, and phase transformation) is needed. However, coupled simulations are time consuming and costly. Therefore, the current study proposes a simplified method focused on the forming for the hot stamping simulation of a coupled torsion beam axle (CTBA) tubular beam. In this simplified method, non-isothermal conditions were assumed and only conduction was considered, since it represents the majority of the heat transfer during hot stamping. In addition, temperature and strain rate effects were also included. Moreover, an isothermal simulation was conducted and compared with a non-isothermal simulation. Finally, the simulations were verified by experiments. In conclusion, the proposed method is shown to be effective for the development of tube-type parts, and it effectively predicts the deformation of the tubular beam during hot stamping.