• 한국대기환경학회지
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• 제9권4호
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• pp.310-319
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• 1993

A pilot study was conducted in order to investigate the concentrations of indoor and outdoor VOCs (Volatile Organic Compounds) at ten homes and four building offices in Seoul during March-April, 1993. The five components of VOCs(Benzene, Toluene, Ethylbenzene, o-Xylene, m/p-Xylene) were collected using charcoal tube and were analysed using Gas Chromatography(GC) with a Flame Ionization Detector(FID). The mean concentations of indoor VOCs were shown as Benzene of 38.9 .mu.g/m$^{3}$. Toluene of 165.0 .mu.g/m$^{3}$, Ethylbenzene of 21.7 .mu.g/m$^{3}$, o-Xylene of 11.6 .mu.g/m$^{3}$ and m/p-Xylene of 29.3 .mu.g/m$^{3}$, but those corresponding that indoor levels of VOCs were higher than corresponding outdoor levels. The ratio of indoor and outdoor VOCs were higher than corresponding outdoor levels. The ratio of indoor and outdoor VOCs concentrations was 0.99 for Benzene, 1.23 for Toluene, 5.86 for Ethylbenzene, 5.23 for o-Xylene, 2.41 for m/p-Xylene in homes, while 2.02 for Benzene, 1.15 for Toulene, 0.96 for Ethylbenzene, 1.41 for o-Xylene, 1.38 for m/p-Xylene in offices, respectively. The mean concentrations of VOCs in homes were higher than those levels in offices, while the mean concentration of VOCs during active hour of occupants in a day were higher 1-3 times than the levels during non-active hour. Comparing VOCs levels by building's age, the mean concentrations of Benzene, o-Xylene and m/p-Xylene were higher in new building than old building, but the mean concentrations of Toluene and Etylbenzene in new building were lower than old building. The mean concentrations in all components of VOCs in smoking area were higher than non-smoking area. These results suggested that the VOC levels were affected by various indoor characteristics and behavioral activity of occupants.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.268.1-268.1
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• 2007

• 한국전기전자재료학회논문지
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• 제16권12S호
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• pp.1195-1199
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• 2003

In this study, in order to develop the low temperature sintering ceramics for multilayer piezoelectric transformer, dielectric and piezoelectric properties of PSN-PZT[0.91Pb(Sb$\sub$1/2/Nb$\sub$1/2/)$\sub$0.03/(Zr$\sub$0.495/Ti$\sub$0.505/)$\sub$0.97/O$_3$-0.04Pb(Ni$\sub$1/2/W$\sub$1/2/)O$_3$+0.05BiFeO$_3$+0.3wt％MnO$_2$+0.6wt％CuO〕 ceramics were investigated according to Zr/Ti ratio. As Zr/Ti ratio is increased, electromechanical coupling factor(k$\sub$p/) and dielectric constant increased and then decreased after the ratio of Zr/Ti=50/50. Also, mechanical qualify factor(Q$\sub$m/) decreased and then increased after the ratio of Zr/Ti=50/50.

• 한국세라믹학회지
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• 제41권8호
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• pp.593-598
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• 2004

1 $\mu$m이하의 전고상 리튬 박막전지의 구현을 위해 펄스 레이저 증착법을 이용하여 Pt/TiO$_2$/SiO$_2$/Si 기판위에 LiCoO$_2$정극을 증착온도와 Li/Co 간의 몰 비율을 변화시켜가며 성장시켰다. 특히, Li/Co=1.2의 조성을 갖는 LiCoO$_2$를 50$0^{\circ}C$의 증착온도에서 성장시킬 경우 53 $\mu$Ah/$cm^2$-$\mu$m의 높은 초기 용량값을 가지며 100 싸이클 후에도 67.6%의 용량값을 유지하였다. LiCoO$_2$/Pt/TiO$_2$/SiO$_2$/Si위에 고체 전해질인 (Li, La)TiO$_3$를 비정질상으로 하여 PLD방법으로 낮은 온도대역에서 증착온도를 다양하게 하여 증착하였다. 10$0^{\circ}C$의 증착온도에서 LiCoO$_2$Pt/TiO$_2$/SiO$_2$/Si위에 성장시킨 (Li, La)TiO를 가지고 LiClO$_4$ in PC 안에서 Li anode와 충$.$방전 측정 결과 약 51$\mu$Ah/$cm^2$-$\mu$m의 초기 용량값을 나타내었으며 100싸이클 후에도 90%의 훌륭한 방전용량의 보존력을 나타내었다. 비정질상의 (Li, La)TiO$_3$ 고체 전해질은 전고상 박막전지로의 구현이 가능하다.

• 천문학회보
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• 제38권2호
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• pp.34.1-34.1
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• 2013

Interstellar ices (e.g., $H_2O$, $CO_2$, and CO ices) are formed on the surface of dust grains in dense molecular clouds. In a near-infrared spectrum, we can observe deep absorption features particularly due to $H_2O$ ice at $3.05{\mu}m$ and $CO_2$ ice at $4.27{\mu}m$. These interstellar ices have many pieces of information on the interstellar environment. Among various ices, $CO_2$ ice is one of the most important ones as a probe of the interstellar environment. That is because $CO_2$ ice is a secondary product unlike $H_2O$ and CO ices which are primarily formed on dust grains. Past studies for $CO_2$ ice in nearby galaxies were performed only for the galactic center in a few galaxies. In order to utilize the information from $CO_2$ ice effectively, it is valuable to perform mapping observations of ices on a galactic scale. With AKARI, we obtain the spatially-resolved near-infrared ($2.5-5.0{\mu}m$) spectra for the central ~1 kpc region of the nearby starburst galaxy M 82. These spectra clearly show the absorption features due to interstellar $H_2O$ and $CO_2$ ices, and we created their column density maps. As a result, we find that the spatial distribution of $H_2O$ ice is significantly different from that of $CO_2$ ice; $H_2O$ ice is widely distributed, while $CO_2$ ice is concentrated near the galactic center. Our result for the first time reveals spatial variations in $CO_2/H_2O$ ice abundance ratio on a galactic scale, suggesting that the ice-forming interstellar environment changes within a galaxy. In this presentation, we discuss the cause of the variations in the ice abundance ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.161-164
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• 2003

This experimental investigation was conducted to examine the seismic performance of reinforced concrete bridge columns. The columns were subjected to a constant axial load and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement ($P_s$ =0.96, 1.44 per cent) and axial load ratio (0.05, 0.1, 0.2 P/$P_o$). Test results show that bridge columns with 50 per cent higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-02 showed ductile behaviour. For bridge columns with axial load ratio(P/$P_o$) less than 0.2, the ratio of $M_{max}$ over $M_{aci}$, nominal moment capacity predicted by ACI 318-02 provisions, is consistently greater than 1 with approximately a 20 percent margin of safty.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
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• pp.83-87
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• 2005

본 연구에서는 단일 포트 그레인 형상을 갖는 하이브리드 추진 시스템의 고체 연료 L/D 비 변화에 따른 연소 특성을 고찰하였다. 본 연구를 위해 그레인 포트 직경이 같은 경우와 그레인 길이가 같은 경우로 나누어 L/D 비 변화에 관한 실험을 수행하였다. 그레인 포트 직경이 같은 경우 L/D 비 변화에 따른 후퇴율은 큰 차이가 없었으며 L/D 비가 클수록 O/F 비는 낮았고 추력은 높았다. 그레인 길이가 같은 경우 L/D 비 변화에 따른 O/F 비와 추력은 큰 차이가 없었으며 L/D 비가 작을수록 후퇴율은 높았다.

• The Korean Journal of Ecology
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• 제23권1호
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• pp.39-43
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• 2000

1996년 7월 하순부터 9월 하순에 걸쳐 동경농공대학 농학부 부속부중농장(동경도 부중시)의 대두(Glycine max)개체군을 대상으로 미기상학적 플럭스측정방법의 하나인 열수지법을 이용하여 CO₂ 플럭스와 O₃ 플럭스를 측정하였다. CO₂ 플럭스와 O₃ 플럭스는 엽면적지수(LAI)의 변화에 영향을 받았으며, LAI가 2.0이상일 경우 CO₂ 플럭스는 광합성유효발사량(PAR)과 정비례관계가 있었다. O₃ 플럭스는 측정 기간 중 항상 양의 수치를 나타냈으며, 평균치는 0.5 mol m/sup -2/S/sup -1/이었다. 또한 CO₂와 O₃ 침착속도사이에는 정비례관계가 있었다 (LAI>2.0).

• E2M - 전기 전자와 첨단 소재
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• 제9권10호
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• pp.1060-1065
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• 1996

We have studied the magnetoresistance phenomena on spin valve thin films of antiferromagnetic NiO/CoO. Interlayer coupling oscillates between the antiferrocoupling and ferrocoupling with the variation of Cu thickness. The exchange coupling strength between NiO (antiferromagnetic) and NiFe(ferromagnetic) as a function of NiO texture and interface roughness is investigated by CoO insertion. CoO has significantly higher anisotropy in the (111) plane and interface roughness. It seems that the MR-ratio is increased by CoO inserted films. From the AFM and XRD data, the increase of MR-ratio and exchange field is influenced by the roughness of CoO.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.171-174
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• 2004

The surge characteristics of $Pr_6O_{11}$-based ZnO varistors consisting of $ZnO-Pr_6O_{11}-CoO-Cr_2O_3-Er_2O_3$ ceramics were investigated with sintering temperature in the range of $1335{\sim}1345^{\circ}C$. As the sintering temperature is raised, the average grain size was marked1y increased in the range of $9.67{\sim}14.07\;{\mu}m$ and the ceramic density was increased in the range of $5.46{\sim}5.59\;g/cm^3$. While, the nonlinear exponent was decreased in the range of 64.9~44.1 and the clamping voltage ratio was improved in the range of 1.99~2.08. The best varistor properties was obtained from the varistors sintered at $1335^{\circ}C$, exhibiting a maximum (64.9) in the nonlinear exponent and a minimum (1.99) in the clamping voltage ratio.