• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.191-196
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• 1997

As a part of International Criticality Safety Benchmark Evaluation Project (ICSBEP), SAXTON critical experiments were reevaluated. The effects on $K_{eff}$ of the uncertainties in experiment parameters, fuel rod characterization, soluble boron, critical water level, core structure, $^{241}$ Am and $^{241}$ Pu isotope number densities, random pitch error, duplicated experiment, axial fuel position, model simplification, etc., were evaluated and added in benchmark-model $k_{eff}$. In addition to detailed model, the simplified model for Saxton critical experiments was constructed by omitting the top, middle, and bottom grids and ignoring the fuel above water.r.r.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.6
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• pp.143-148
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• 1994

In order to study the effect of D.C resistivity of sample on electromagnetic loss of ferrite at microwave frequency, samples were prepared for having differences in resistivity of an order of two. Microwave permeability($\mu$), permitivity($\varepsilon$) and effective linewidth(${\Delta}H_{eff}$), and ferromagnetic resonance linewidth(${\Delta}$H) were characterized. Tan${\delta}{\mu}$, tan${\delta}{\varepsilon}$ and ${\Delta}H_{eff}$ were decreased with increasing the resistivity and (${\Delta}$H) was increased with increasing Fe concentration, which was due to an increase of anisotropy magnetic field (=Ha).

• Journal of the Korean Society of Safety
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• v.7 no.2
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• pp.47-56
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• 1992

The retardation effect of fatigue crack propagation after cyclic overloading seems to be affected by strain hardening exponent. Namely, for the material with high values of n, the delay effect is found to be severe. We proposed a modified crack retardation equation which may apply the retardation of fatigue crack growth after a cyclic overloading, as (da/dN)'$_{cyc}$=($\mu$n＋λ)B $\Delta$ $K^{q}$ /[(1－ $R_{eff}$) $K_{cf}$ －$\Delta$K]. where, $R_{eff}$ is effective stress ratio [＝( $K_{min}$－K, os)/( $K_{max}$－ $K_{res}$)] The constants $\mu$＝－0.5 and λ＝0.6, and the values are found to be identical for materials such as aluminum (A 1060), steel (SS 34), brass ( $B_{s}$ SIB) and stainless steel (SUS 304) used in this investigation. (SUS 304) used in this investigation.ation.n.n.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.127-129
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• 1999

In this paper, we analogized effective thermal conductivity ($k_{eff}$) and effective heat capacity($pc_{p.eff}$) of insulators and the air in coil portions of linear pulse motor for CEDM(Control Element Drive Mechanism). The errors of simulated results are under 1.6% when compared with experimental results. And we carried out temperature rise of linear pulse motor for CEDM by the experiment.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.54-58
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• 1993

The fatigue growth behavior of short cracks were studied various load ratios. Computer-aided unloading elastic compliance method was employed to measure the closure and the length of short cracks. In the dc/dN-$\Delta$K relationships. the decreasing behavior of the growth rate of short cracks is due to the decrease of crack opening ratio with increasing crack length. Irrespective of load ratio. the growth rate of short cracks can be well decribed in terms of the effective stress intensity factor range $\Delta$K$_{eff}$, which is calculated on the base of crack closure. dc/dN-$\Delta$K$_{eff}$ relationships of short cracks are found to coincide well with the corresponding long crack relationships. accordingly. the growth rate of short cracks can be predicted using that of long cracks.ort cracks can be predicted using that of long cracks.cks.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.270-271
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• 2007

In this study, piezoelectric properties of PZW-PMN-PZT multilayer actuator sintered at $900^{\circ}C$ low temperature have been investigated. The multilayer actuator was fabricated by tape casting methods. The density above $8[g/cm^3]$ was obtained at all the specimens. Also, according to increasing the number of multilayer, effective electromechanical coupling factor$(k_{eff})$ showed increasing trend. The $k_{eff}$ of multilayer actuator showed the maximum value of 0.283 at 11 layer. However, according to increasing the number of multilayer, mechanical quality factor(Qm') showed decreasing tend. The Qm' of multilayer actuator showed the maximum value of 920 at 5 layer.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.844-846
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• 2004

가상 기계란 하드웨어로 이루어진 물리적 시스템과 달리 소프트웨어로 제작되어 논리적인 시스템 구성을 갖는 개념적인 프로세서이다. 기상 기계 기술은 프로세서나 운영체제가 바뀌더라도 응용프로그램을 변경하지 않고 사용할 수 있는 장점이 있다. 임베디드 시스템을 위한 기상 기계 기술은 모바일 장치나 디지털-TV 등에 탑재할 수 있는 핵심기술로서 다운로드 솔루션에서는 꼭 필요한 소프트웨어 기술이다. 현재 EVM이라 명명된 임베디드 시스템을 일한 가상 기계에 대하여 연구가 진행 중이다. 이러한 연구의 일환으로 본 논문에서는 기존의 가상 기계를 위안 실행 파일 포맷들의 분석을 기반으로 하여 임베디드 시스템을 위한 실행 파일 포맷인 EVM 파일 포맷(EFF)을 정의한다. 또한 제안한 EFF의 완전성을 증명하기 위하여, 기존에 널리 사용되고 있는 실행 파일인 클래스 파일을 이용해서 구조적으로 증명한다.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.811-816
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• 2022

This work presents the methodology used to expand the capabilities of the Monte Carlo code OpenMC for the calculation of reactor kinetic parameters: effective delayed neutron fraction β_eff and neutron generation time L. The modified code, OpenMC(Time-Dependent) or OpenMC(TD), was then used to calculate the effective delayed neutron fraction by using the prompt method, while the neutron generation time was estimated using the pulsed method, fitting Λ to the decay of the neutron population. OpenMC(TD) is intended to serve as an alternative for the estimation of kinetic parameters when licensed codes are not available. The results obtained are compared to experimental data and MCNP calculated values for 18 benchmark configurations.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.50.2-50
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• 1998

• Progress in Superconductivity
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• v.4 no.2
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• pp.137-143
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• 2003

In measuring the microwave surface resistance of high-Tc superconductor (HTS) films using the dielectric-loaded cavity resonator method, one of the most important factors that limit the measurement sensitivity is the measurement error in the loss tangent ($tan\delta$) of the dielectric rod placed inside the cavity. We have measured the effective surface resistance ( $R_{S}$ $^{eff}$) of$ YBa_2$$_Cu3$$_{7-{\delta}}$ (YBCO) films and the $tan\delta$ of rutile ($TiO_2$) using the 'two-tone'method suggested by Kobayashi et at. [IEEE, MTT-S Digest, 495, (2001)], which enables simultaneous measurements of both the $R_{S}$ $^{eff}$ fof HTS films and the $tan\delta$ of the rutile with high sensitivity. A rutile-loaded cavity resonator with the $TE_{012}$ and $TE_{021}$ resonant frequencies at 13.67 - 14.01 GHz is used for this purpose. At temperatures where the two modes do not couple with other modes, the $R_{S}$ $^{eff}$ of YBCO films and $tan\delta$ of rutile measured by the two-tone method appear to match well with the corresponding values measured using the reported $tan\delta$ values of sapphire within 10 %. Usefulness of the 'two-tone' method for microwave characterization of HTS films and dielectrics is discussed.d.ielectrics is discussed.ussed.