• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.51-56
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• 1990

Six small-scale reinforced concrete beam-column joint specimens subjected to monotonic and cyclic loading were tested to investigate the effects of strength of concrete. Variables are 1)compressive strength of concrete(f' c=300, 700kg/㎠), 2)shear span to depth ratio (a/d=4.7, 2.0). The major results of this test were: 1)flexural strength of high strength concrete beam-column joint was not affected too much by the compressive strength of concrete, 2) flexural cracks emerge to inside of beam deeply for high strength concrete member.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.34-39
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• 1991

It is well-known that concretes under sea water environment show remarkably degrading phenomena physically by repeatable freeze-thawing action and chemically by penetration of soluted ions in sea water. In this study the influences of type of blending materials, their dosage and W/C ratio on freeze-thawing resistances of hardened cement concrete using foy ash, ground blast furnace slag, silica fume, EVA and SBR under sea-water environment were investigated.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.390-394
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• 1989

The stored elastic strain energy due to the thermal expansion mismatch between the thermally oxidized crystalline layer (cristobalite) and CVD Si3N4($\alpha$-Si3N4) on cooling form high oxidation temperature (1000-140$0^{\circ}C$) to room temperature, releases through the crazing of film and lifting at the SiO2/Si3N4 interface. The ratial equation (1/n) which corresponds to the ratio of the relaxation of the stored elastic stain energy due to crazing of film to the total energy, is derived under the assumption of the square crazed pattern, as follow. 1/n={8${\gamma}$(1-v)2}/(ΔL2dE) The ratial equation suggests the reason for the lifting at the SiO2/Si3N4 interface which was observed in this research.

• Journal of the Korean Society of Safety
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• v.8 no.1
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• pp.47-53
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• 1993

Residual Deformation Analysis(RDA) is a new method for ratings of the continuous bridges. The RDA makes it possible to expand the inelastic steel girder bridge design method set forth in the American Association of State Highway Officals'(AASHTO) Guide Specifications for Alternate Load Factor Design Procedures for Steel Beam Bridges Using Braced Compact Sections(1986) into an inelastic rating method. It is a method to assess the residual moments and deformations that are set up in a beam that has been loaded into the post-elastic range This method combines classical elastic conjugate beam theory with linear moment-rotation relationships for midspan inelastic positive moment. The limit state is inelastic serviceability limit. which is defined as the ratio of the span to midspan inelastic deflection(C=L/D).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.4
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• pp.822-833
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• 1996

The video coding for very low bit rate has recently received considerable attention, but conventional block based transform coding schemes suffer from the blocking effect for the constraints of bit rates. In this paper, we present a video coding sysem suing multi-resolution motion estimation/compensation with variable size block(VMRME/C) and multi-resolution vector quantization(MRVQ) in wavelet transform domain for very low bit rate coding. It is shown that the presented scheme has better performance in the peak signal-to-nose ratio(RSNR) by 0.2-0.6 dB as well as subjective quality than that of conventional block based transform video coding techniques(especially, H. 263 which is DCT based video coding).

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.429-430
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• 2012

본 논문에서는 LED 구동용 전원장치의 필터커패시터와 변압기 권선비에 따른 MOSFET의 전압 정격 및 스위칭 손실 특성 등을 다루었다. 스위칭 손실을 최소화 하려면 변압기 권선비를 최적화할 필요가 있다. 또한 필터커패시터 값이 MOSFET의 전압정격에 영향을 미치므로 이를 고려한 설계가 필요함을 확인하였다.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.657-659
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• 1993

We have developed a repetitive TEA $CO_2$ laser excited by a magnetic switch pulse source, and have measured the laser output energy for the mixing ratio of the laser gas mixture in single pulse. As a result of experiments, we have obtained the laser output energy of 252 mJ($\eta_{intrinsic}$=7.8%) in $CO_2:N_2$:He=1:1:8(1 atm.). At a repetition-rate frequency of 10 Hz, an average laser power of 1.5 W was obtained.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.1
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• pp.45-49
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• 2006

The present investigation was conducted to know the effects of host age on development and morphological characteristics of Nesolynx thymus, a gregarious ectopupal parasitoid of the uzi fly, Exorista bombycis, a serious en do-larval parasitoid of the silkworm, Bombyx mori L. For experimentation, 3 - 11 day-old pupae of E. bombycis were exposed to 2 day-old adults of N. thymus at $25{\pm}2^{\circ}C\;and\;60{\pm}10%$ RH. A highly significant negative correlation between host age and the following development and morphological characteristics of the parasitoid was observed: number of pupae parasitised, total adult recovery, sex ratio and recovery, longevity, body length, wing span, abdomen length, and abdomen width of females. The findings of the present study clearly demonstrate that various development and morphological parameters of N. thymus are influenced by the age of E. bombycis pupae.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.393-396
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• 2005

This paper is concerned with the drawing process of $Al-1\%Si$ bonding wire. In this study, the finite-element model established in previous work was used to analyze the effect of various forming parameters, which included the reduction in area, the semi-die angle, the aspect ratio, the inter-particle spacing and orientation angle of the fine Si particle in drawing processes. The finite-element results gave the consolidation condition. From the results of analysis, the effects of each forming parameter were determined. It is possible to obtain the Important basic data which can be guaranteed in the fracture prevention of $Al-1\%Si$ wire by using FE-Simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.257-260
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• 2004

This study aims to evaluate factors of ceiling structure influencing to the floor impact sound. For this reasons, we measured the vibration of ceiling and the floor impact sound by ceiling structure. The main results from this study are that ceiling structure makes worse to non-ceiling structure for an effect of air layer in heavy-weight floor impact sound. But it has an effect on light-weight floor impact sound about $2\sim8dB$.