• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1983-1985
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• 1999

The dielectric constant of a monolayer on a material surface was calculated with consideration of the local field acting on polar molecules with a permanent dipole moment, and the interaction working between the molecules and a material. It is revealed that the dielectric relaxation time r of monolayers in the isotropic polar orientational phase is determined using a linear relationship between the monolayers compression speed a and the molecular area. The dielectric relaxation time of phospholipid monolayers was examined on the basis of analysis developed here.

• Korean Institute of Interior Design Journal
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• no.21
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• pp.173-181
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• 1999

Design has been proceeding to 21 century undertaking the many-sided and complicated characteristics of the modern industrialized society much more heavily comparing to past. The rapid change of technology and media of communication faces the new concept of relationship between users and environment, and newly developed material leads designers to change the way of building concept and the process of designing. Especially the important points of user-friendly and environment-friendly approaching for designing influences over choosing, controlling meterials and forming the structure and shape organically, or simply. From the tendency of chairs designed in 1990s the very adaptable new material shows both the unlimited possibility for new design is in the turn of this century, but also it can be analogized that 'the design which can make users think' will be the philosophical basis for future desigv.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.425-428
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• 2009

Aerospace engine application needs to stand high temperature and pressure. Because of its mechanical properties such as high strength at high temperature, Alloy 718 is used aerospace engine application about 80%. But alloy 718's mechanical properties cause some problem to manufacturing profile ring like damage of material and mold. In this study, alloy 718's mechanical properties investigated for knowing its formability and using FE-Simulation for designing profile ring roll process and mold shape. Profile ring rolling processing is designed with "Initial material$\rightarrow$Blank$\rightarrow$Linear Ring$\rightarrow$Profilering". Blank's heating temperature is setting $1100^{\circ}C$ for manufacturing a trial profile ring on the basis of FE-Simulation. As a result of manufacturing alloy 718 profile ring, it is possible to make near target profile shape ring with all of the processing condition which gives in this study.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.209-216
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• 2004

Numerical analysis is carried out to identify the appropriateness of the design codes that is available for the tensile design of fastening system at Nuclear Power Plant (NPP) in this study. This study is intended for the cast-in-place anchor that is widely used for the fastening of equipment in Korean NPPs. The microplane model and the elastic-perfectly plastic model are employed for the quasi-brittle material like concrete and for the ductile material like anchor bolt as constitutive model for numerical analysis and smeared crack model is employed for the crack and damage phenomena. The developed numerical model is verified on a basis of the various test data of cast-in-place anchor. The appropriateness of both ACI 349 Code and CCD approach of CEB-FIP Code is evaluated for the tensile design of cast-in-place anchor and it is proved that both design codes give a conservative results compared with real tensile capacity of cast-in-place anchor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.463-464
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• 2009

This paper describes the political and technical trends of foreign 10 countries advanced in solar energy field. In the trend analysis, a couple of statistical data and related references were compared. As a result, all of the advanced countries mentioned in this paper have their own PV policy strategies and regulatory frameworks to strengthen their stable market structures and have financially supported by various types of incentives and tariff systems. It was confirmed that the political basis and technical regulations including electrical safety have to be prepared as soon as possible at both national and rural level in this country.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.267-268
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• 2009

Resistance standards from 1 ${\Omega}$ to 100 $k{\Omega}$, with calculable frequency dependencies of up to 1 MHz, have been developed for the calibration of commercial inductance-capacitance-resistance (LCR) meters and impedance analyzers. The resistors are designed on the basis of single bifilar loops. The typical resistance change from dc to 1 MHz is from 200 to $800\;{\mu}{\Omega}/{\Omega}$. According to the measurement results, the frequency dependencies of the resistors are severaltimes lower than the measurement uncertainty of commercial LCR meters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.182-186
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• 1995

In this pacer, it is examined and confirmed that the R factor which is compensated after analyzing the characteristics of superconductor resulted from this experimented theory with the computer simulation, is refined to R$\sub$WP/=8.83[%], R$\sub$P/=6.47[%], R$\sub$I/=10.08[%], RF=7.19[%], R/eub E/=3.76(%), and on the basis of these experimental data, the significant parameter such as the scale factor(s) and the zero point shift(Z) and FWHM value(U,V,W) are optimized as follows; S =72.0827E-3, Z=0.2146, U=4.2761E-2, V=1.7983E-2, and W=2.6768E-2

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.4 no.2
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• pp.17-23
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• 1993

This study aims to measure the reflection loss and the material constants of the fabricated samples for electromagnectic wave absorber by using $20 mm\phi$ coaxial tube with the endshort-type. The authors have established the extraction algorithm of material constants by one port method, and proved that the results of the experiments were in agreement with the calculated ones. On the basis of the above results, the validity of the proposed measuring method is confirmed. This measurement method could be used effectively for the design of microwave absorber and for its evalustion.

• Fire Science and Engineering
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• v.12 no.1
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• pp.27-33
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• 1998

Arson is one of the serious crime. It shows high increasing rate compared with the past, and the causes of arson are getting diversified and specialized in this modern society. In this thesis, the actual state and tendency of arson during latest 5 years have been analyzed on the basis of 'crime analysis' which is material of the National Police Agency. Based on the above analyzed material, measures for arson in foreign countries are examined and necessary matters to counter arson in Korea are inferred.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.25-28
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• 2004

A fracture was generated by change of clearance and deterioration of material properties on the sheet metal through temperature. This paper describes the results of a prediction about the temperature of the sheet metal during continuous stamping process, because the temperature increase of the sheet metal has a detrimental effect on formability. To analyze the temperature increase of the sheet metal during continuous stamping process, tensile and friction tests were performed from room temperature to 300$^{\circ}C$ at warm condition in this study. As temperature increase, tensile strength, elongation, strain hardening exponent and anisotropy coefficient for each specimens were decreased. On the other hand, friction coefficients were increased. From the FE-simulation results, temperature upward tendency was identified on dies and sheet metal. These observations are rationalized on the basis of the material properties, friction coefficient vs. temperature relationship for the sheet.