• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.346-347
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• 2000

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.429-430
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• 2000

• 대한환경공학회지
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• 제22권12호
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• pp.2255-2261
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• 2000

본 연구에서는 질소산화물 저감기술의 하나인 선태적 촉매 환원법(SCR)을 이용하여 실제 디젤엔진에서의 $NO_x$저감에 관한 실험을 수행하였다. 특히 선택적 촉매 환원법 중에서 금속산화물(metal oxide)과, 페롭스카이트(perovskite)형의 환원촉매를 사용하였으며 ${\gamma}-Al_2O_3$ 담체에 여러 가지 주촉매, 조촉매를 사용하여 배기가스 온도 범위 내에서 높은 $NO_x$제거효율을 가지고 있는 $LaCuMnO_x$을 선택하였다. $NO_x$ 제거를 위한 실험은 실제 디젤엔진에서 배출되는 배기가스를 이용하였으며 공간속도 $3,300h^{-1}$인 상태에서 촉매 반응기 통과전후의 $NO_x$의 변화량을 측정하였다. 그 결과 페롭스카이트 형태의 촉매가 활성화 온도범위가 우수함을 알 수 있었고 $LaCuMnO_x$의 경우에는 촉매 온도범위 $150{\sim}450^{\circ}C$하에서 $NO_x$의 제거효율이 전반적으로 우수하였다.

• 디지털산업정보학회논문지
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• 제12권3호
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• pp.25-31
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• 2016

Mechanical properties of Y2O3-containing tetragonal ZrO2 polycrystals(Y-TZP) were investigated. Several additives were used to modify the hardness and fracture toughness of Y-TZP. The effects of these individual additives were discussed and their interactions were also analysed. Each additive, such as CoO, Fe2O3, MnO2 was found to deteriorate the mechanical properties of Y-TZP when it was used singly. But the fracture toughness of Y-TZP was significantly improved when these additives and Al2O3 were added in combination at a certain ratio. The addition of CoO, Fe2O3 and MnO2 into Y-TZP resulted in the more complex behavior of fracture toughness and hardness. The specimen with 1.5 wt%-Fe2O3, 3.0 wt% -Al2O3 and 1.5 wt%-CoO showed the monoclinic to tetragonal phase ratio of 18% and the highest toughness of $10.8MPa{\cdot}m1/2$ with Vickers hardness of 1201 kgf/mm2. However, the toughness decreased as the ratio increased and macrocracks developed beyond the ratio of 25%. Sample No. 16 is improved high Physical and Mechanical Properties.

• 한국추진공학회지
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• 제13권1호
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• pp.19-26
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• 2009

과산화수소 단일추진제 추력기의 응답성에 대한 실험적 연구를 수행하였다. 촉매베드의 특성을 배제하고 추력기 설계 인자에 따른 응답특성을 살펴보기 위해 $MnO_2$/$Al_2O_3$를 주 촉매로 고정하였다. 세 가지 50 N 급 추력기를 이용하여 인젝터 방식, ullage volume, 촉매 펠렛 크기, 반응기 부피에 따른 응답 속도를 측정하였다. 측정 결과 16-20 mesh 크기 촉매, shower head 인젝터를 사용한 경우 점화지연, 압력 상승 및 하강시간은 각각 14, 108, 94 ms로 상용 하이드라진 추력기 응답성에 근접한 특성을 보였다.

• Environmental Engineering Research
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• 제20권4호
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• pp.329-335
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• 2015

The effects of ion-doping on $TiO_2$ nanotubes were investigated to obtain the optimal catalyst for the effective decomposition of Rhodamine B (RB) through UV photocatalytic oxidation process. Changing the calcination temperature, which changed the weight fractions of the anatase phase, the average crystallite sizes, the BET surface area, and the energy band gap of the catalyst, affected the photocatalytic activity of the catalyst. The ionic radius, valence state, and configuration of the dopant also affected the photocatalytic activity. The photocatalytic activities of the catalysts on RB removal increased when $Ag^+$, $Al^{3+}$ and $Zn^{2+}$ were doped into the $TiO_2$ nanotubes, whereas such activities decreased as a result of $Mn^{2+}$ or $Ni^{2+}$ doping. In the presence of $Zn^{2+}$-doped $TiO_2$ nanotubes calcined at $550^{\circ}C$, the removal efficiency of RB within 50 min was 98.7%.

• 한국환경보건학회:학술대회논문집
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• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
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• pp.76-85
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• 2003

Mass and elemental dry deposition fluxes and ambient particle size distributions were measured using dry deposition plates and a cascade impactor, from March to November 1998 in Seoul, Korea. During the spring sampling period several yellow sand events characterized by long range transport from China and Mongolia impacted the area. During these events the mass fluxes were statistically the same as during springtime non-yellow-sand events. However, most elemental fluxes were higher. In general, the flux ratios of both crustal (Al, Ca, Mn) and anthropogenic elements (Ni, Pb) to total mass measured during the daytime yellow-sand events were substantially higher than those measured in spring daytime during non-yellow-sand time periods. During all seasons the average measured daytime fluxes were about two times higher than at nighttime. The flux of primarily anthropogenic metals (Cu, Ni, Pb, Zn) and Mn was on average one to two orders of magnitude lower than the flux of the crustal metals Al and Ca. As is typically found two modes, fine (0.1∼l.0 $\mu\textrm{m}$) and coarse (1.0∼10.0 $\mu\textrm{m}$) were present in the measured size distributions (<10 $\mu\textrm{m}$). The particles in the coarse mode constitute a major portion of the measured mass size distribution during the yellow-sand events possibly due to the long-range transport of those particles from China.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.913-917
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• 2003

In the electronic components and devices fabrication, thin film resistors with low TCR(temperature coefficient of resistance) and high precision have been used over 3 GHz microwave in recent years. Ni-Cr alloys thin films resistors is one of the most commonly used resistive materials because it has low TCR and highly stable resistance. In this work, we fabricated thin film resistors using Evanohm alloys target(72Ni-20Cr-3Al-4Mn-Si) of s-type with excellent resistors properties by RF-sputtering. Also we reported best deposited conditions of thin film resistors for microwave to observe microstructure and electronic properties of thin film according to deposited conditions(between target and substrate, power supply)

• 한국식품영양학회지
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• 제10권3호
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• pp.325-329
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• 1997

서산 6쪽 마늘 중의 inulinase를 추출하여 황산암모늄 침전가 Sephadex G-150여과 등을 통하여 9.1%의 수율로 부분정제하였다. 부분 정제된 inulinase는 4$0^{\circ}C$와 pH 6.0에서 inulin을 가장 잘 분해시켰고 7$0^{\circ}C$ 이하와 pH 5.0~8.0에서 안정하였다. 또한 이 효소는 Al3+, Mn2+, Hg2+, Cd2+ 및 EDTA에 의하여 심하게 실활되었고 inulin에 대한 Km값은 0.22%이었다.

• 분석과학
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• 제15권4호
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• pp.321-328
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• 2002

From May 1999 to July 2000, concentration of 17 metals (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sr, V, Zn), 4 ions (${NH_4}^+$, $Cl^-$, ${NO_3}^-$, ${SO_4}^{2-}$) and pH in rainwater were investigated. The volume-weighted mean concentrations (VWM) of ${NO_3}^-$ and ${SO_4}^{2-}$ were 16.0 and $17.0{\mu}mol\;L^{-1}$. The average pH was 4.53, which ranged from 3.83 to 6.06. The characteristic variations of these species were investigated in terms of the source of these species by principal component analysis (PCA) and interelement correlation coefficients. The elements were classified into three categories: anthropogenic source (Cd, Cu, Fe, Ni, Pb, V, Zn, ${NH_4}^+$, ${NO_3}^-$, ${SO_4}^{2-}$ and $H^+$), soil and crust dust (Al, Ba, Ca, Fe, Mn) and sea salts (Mg, Na, $Cl^-$). In addition, we compared the concentrations in rainwater, which were taken on the same day in three sites (Higashi-Hiroshima, an urban-facing area and a mountain-facing area of Mt. Gokurakuji) in order to examine the regional effect against the concentrations in them. At the urban-facing area of Mt. Gokurakuji, the concentrations of chemical compositions were higher than other areas.