• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.18-23
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• 2009

After the installation of electric cables at block, PE(pre-erection) and hull stages, the coating stains on the electric cable sheath were unavoidably occurred by additional painting process. According to class rules paint or coating applied on the electric cables shall not adversely affect the mechanical, chemical of fire resistant characteristics of the electric cable sheath. However, there has not been quantitatively studied about the effect of coating stains on properties of sheath materials. In this study, we tried to investigate the effect of coating stains on the performance and deterioration of sheath materials by using FTIR, SEM analysis, flame retardant, high potential voltage and tensile test. The results sowed that coating stains, which were occurred during painting work on site could not adversely affect on the performance and deterioration of sheath materials.

• 한국재난정보학회 논문집
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• 제15권4호
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• pp.531-539
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• 2019

연구목적: 국내 적층형 물류창고의 스프링클러 설계적용을 위한 수용물품 등급분류방법을 제시함을 목적으로 한다. 연구방법: 현장조사와 미국 NFPA, FMDS, 유럽 EN 및 일본의 분류 기준을 비교분석하고 ISO 12949에 따른 등급별 연소특성 실험을 수행하였다. 연구결과:연소열을 기준으로 특급, 상급, 중급 및 경급의 등급분류방법을 제안하였다. 결론: 물품 등급별 최대 소화강도를 확보하는 스프링클러설계기준의 적용이 필요하다.

• 한국안전학회지
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• 제27권1호
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• pp.26-31
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• 2012

Wood-plastic composites represents a growing class of materials used by the residential construction industry and furniture industry. In this study, the effect of flame retardants on the flammability and mechanical properties of wood flour-high density polyethylene(HDPE) composites were studied. we were manufactured wood flour-HDPE composites by modular intermeshing co-rotating twin screw extruder with L/D ratio of 42. The flame retardant properties were used limiting oxygen index(LOI) and mechanical properties were measured by universal testing machine(UTM). The Morphological analysis of composites were analyzed by Scanning electron microscope(SEM). It was found that Ammonium polyphosphate can effectively reduce the flammability of the wood flour-HDPE composites. Marginal reduction in the mechanical properties of the composites was found with addition of flame retardants. SEM images showed that the coupling agent improved wood flour-HDPE interfacial bonding.

• 전기학회논문지
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• 제66권1호
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• pp.243-248
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• 2017

This study used general carbon fibers(CF), which can be utilized for a low voltage cable screen, as well as metal-coated carbon fibers(MCF) to make cables and analyzed the properties of electromagnetic effectiveness. Both braid CF and MCF cables with 3,000 strands, 16 spindles, and braid density of 90% or over were adopted. The tape-type MCF specimens were spread into a tape(width: 15mm) using a hot melt to make a cable. The shield effectiveness was measured up to the 1GHz range in accordance with IEC 62153-4-6; braid shielded cables featured a superior shielding effect at 63dB than tape-type shielded cables. That was because the tape-type shielded cable has relatively more gaps and holes between carbon fibers than the braid type, resulting in a more inflow or emission of electromagnetic waves. In the case of braid cables, the characteristics of their electromagnetic waves were enhanced, with higher spindles and higher conductivity of carbon fibers. The shield effectiveness of the MCF shielded cable, however, was lower than that of tin-coated one.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권3호
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• pp.102-110
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• 2005

Piezoelectric transformers(PT) are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down PT for the miniaturized adaptor. We propose a PT, operating in thickness extensional vibration mode for step-down voltage. This PT consists of a multi-layered construction in the thickness direction. In order to develop the step-down PT of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and PT designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(Zr$_{x}$Ti$_{1-x}$)O$_{3}$-(1-y)Pb(Mn$_{1/3}$Nb1$_{1/3}$Sb$_{1/3}$)O$_{3}$. In the piezoelectric characteristics evaluations, at y=0.95 and x=0.505, the electromechanical coupling factor(K$_{p}$) is 58$\%$, piezoelectric strain constant(d$_{33}$) is 270 pC/N, mechanical quality factor(Qr$_{m}$) is 1520, permittivity($\varepsilon$/ 0) is 1500, and Curie temperature is 350 $^{\circ}C$. At y = 0.90 and x = 0.500, kp is 56$\%$, d33 is 250 pC/N, Q$_{m}$ is 1820, $\varepsilon$$_{33}$$^{T}$/$\varepsilon$$_{0}$ is 1120, and Curie temperature is 290 $^{\circ}C$. It shows the excellent properties at morphotropic phase boundary regions. PZT-PMNS ceramic may be available for high power piezoelectric devices such as PTs. The design of step-down PTs for adaptor proposes a multi-layer structure to overcome some structural defects of conventional PTs. In order to design PTs and analyze their performances, the finite element analysis and equivalent circuit analysis method are applied. The maximum peak of gain G as a first mode for thickness extensional vibration occurs near 0.85 MHz at load resistance of 10 .The peak of second mode at 1.7 MHz is 0.12 and the efficiency is 92$\%$.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.5893-5900
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• 2012

심정지 또는 중증 외상 환자의 신속한 기도유지는 매우 중요하다. 본 연구의 목적은 후두튜브(LTS)와 후두마스크(PLMA)의 삽관 속도, 성공률, 교육 전 후 자신감 변화를 비교하여 병원 전 단계의 주축을 담당하고 있는 119구급대의 전문기도관리 능력을 향상 시키는데 있다. 연구 대상자는 119구급대원 중 1급 응급구조사 60명(LTS군 30명, PLMA군 30명)이며 마네킹을 대상으로 5분간 3회 실습 후 삽관 소요시간과 성공 여부, 자신감 변화를 측정하였다. 연구결과 LTS와 PLMA를 이용한 삽관 시간은 유의한 차이를 보였고(p=.000), 성공률은 유의한 차이가 없으며, 실험 후 자신감은 유의하게 상승하였다(p=.000). 결론적으로 경추가 고정되고 혀 부종이 있는 외상환자에게 신속한 삽관이 필요한 경우 LTS 사용이 효과적이며 교육을 통하여 전문기도관리 능력을 향상시킬 수 있을 것으로 사료된다.