• 한국분말재료학회지
• /
• 제14권4호
• /
• pp.265-271
• /
• 2007

Electromagnetic wave absorbing materials have been developed to reduce electromagnetic interference (EMI) for electronic devices in recent years. In this study, Fe-Si-B-Nb-Cu base amorphous strip was pulverized using a jet mill and an attritor and heat-treated to get flake-shaped nanocrystalline powders, and then the powders were mixed, cast and dried with dielectric $Al_{2}O_{3}$ powders and binders. As a result, the addition of $Al_{2}O_{3}$ powders improved the absorbing properties of the sheets noticeably compared with those of the sheets without dielectric materials. The sheet mixed with 2 wt% $Al_{2}O_{3}$ powder showed the best electromagnetic wave absorption, which was caused by the increase of the permittivity and the electric resistance due to the dielectric materials finely dispersed on the Fe-based powder.

• Archives of Metallurgy and Materials
• /
• 제66권4호
• /
• pp.983-986
• /
• 2021

This study investigated the recovery behavior of valuable metals (Co, Ni, Cu and Mn) in spent lithium ion-batteries based on Al₂O₃-SiO₂-CaO-Fe₂O₃ slag system via DC submerged arc smelting process. The valuable metals were recovered by 93.9% at the 1250℃ for 30 min on the 20Al₂O₃-40SiO₂-20CaO-20Fe₂O₃ (mass%) slag system. From the analysis of the slag by Fourier-transform infrared spectroscopy, it was considered that Fe₂O₃ and Al₂O₃ acted as basic oxides to depolymerize SiO₄ and AlO₄ under the addition of critical 20 mass% Fe₂O₃ in 20Al₂O₃-40SiO₂-CaO-Fe₂O₃ (CaO + Fe₂O₃ = 40 mass%). In addition, it was observed that the addition of Fe₂O₃ ranging between 20 and 30 mass% lowers the melting point of the slag system.

• 패션비즈니스
• /
• 제18권5호
• /
• pp.69-81
• /
• 2014

Fabric made of 100% silk was dyed with Undaria pinnatifida extracts under different conditions such as varing colorant concentration, temperature, time and dyebath pH. The dye uptake (K/S, value), CIE L*,a*,b* and Munsell values of the dyed samples and mordanted samples were measured. Colorfastness, antibacterial property and UV protection property were also evaluated. As colorants concentration increased, the dye uptake increased progressively and maximum color strength was obtained at 100% V/V. Dye uptake also increased with increasing temperature and time, and the maximum color strength was obtained at $80^{\circ}C$ and 60min. With pre-mordanting, the color of the Al and Fe mordanted silk fabrics was yellow on the Munsell color system, while the Cu mordanted fabric was a greenish color. Al and Fe post-mordanted fabrics had a yellow tone, and the Cu post-mordanted fabric had a yellow greenish tone. The light fastness property of the Cu mordanted silk fabric was relatively good, The effect of Al and Fe mordanting on fastness was insignificant. The antibacterial activity of dyed and unmordanted silk fabric was excellent, whereas fabric dyed and mordanted with Undaria pinnatifida extract demonstrated superior ultraviolet protection.

• 분석과학
• /
• 제20권6호
• /
• pp.524-528
• /
• 2007

Variations of the twenty one metal components (Mg, Al, V, Cr, Co, Sr, Ba, Na, K Mn, Fe, Cu, Zn, As, Hg, Pb, Ca, P, Mo, Cd, Sb) were analyzed in human hair sample by inductively coupled plasma mass spectrometry (ICP-MS). The effect of bleach and permanent wave manipulation on the elemental composition of hair were investigated. It was found that the composition of hair varied with hair bleach and permanent wave. Hair sample was collected from male in the age of thirties. Hair sample (0.05 g) was added to the Teflon digestion bomb together with 1.5 mL of nitric acid and an appropriate amount of In as an internal standard. The sample was then decomposed in the microwave digestion system. In normal hair, the contents of V, Cr, Mn, Fe, Co, Cu, Zn, As, Mo, Cd, Sb and P were increased in permanent wave hair, and Mg, Al, V, Co, Sr, Ba, Na and K were increased in bleached hair. But Mg, Al, Sr, Ba, Hg, Pb, Na, K, and Ca contents were decreased with permanent wave hair, Mn, Fe, Cu, Zn, As, Hg, Pb and Ca contents were decreased with bleached hair.

• 청정기술
• /
• 제20권4호
• /
• pp.375-382
• /
• 2014

금속산화물이 담지된 허니컴 형상의 플라즈마-촉매 반응기를 이용하여 아이소프로필 알코올(isopropyl alcohol, IPA) 저감 및 부산물 생성 거동에 대해 조사하였다. 허니컴 형상의 다공질 세라믹 지지체(주성분: ${\alpha}-Al_2O_3$)에 금속산화물로 산화철($Fe_2O_3$) 또는 산화구리(CuO)를 담지시킨 후, 이 촉매가 동축 원통형 전극구조 내부에 위치하도록 플라즈마-촉매 반응기를 구성하였다. 플라즈마 반응에 의한 IPA 분해속도가 매우 빨랐기 때문에 IPA 분해효율 자체는 금속산화물 담지 여부 및 금속산화물 종류에 관계없이 유사한 것으로 나타났으나, 부산물 생성거동은 촉매종류에 따라 큰 차이를 보여주었다. 아세톤, 폼알데하이드, 아세트알데하이드, 메테인, 일산화탄소 등의 유해 부산물 농도는 $Fe_2O_3/{\alpha}-Al_2O_3$ < $CuO/{\alpha}-Al_2O_3$ < ${\alpha}-Al_2O_3$ 순으로 높게 나타났다. 유량 $1L\;min^{-1}$, IPA 초기농도 5,000 ppm(산소: 10%), 방전전력 47 W의 조건에서 얻어진 $CO_2$ 선택도는 ${\alpha}-Al_2O_3$, $CuO/{\alpha}-Al_2O_3$, $Fe_2O_3/{\alpha}-Al_2O_3$에 대해 각각 40, 80, 95%로서 $Fe_2O_3/{\alpha}-Al_2O_3$가 플라즈마-촉매를 이용한 IPA의 산화에 가장 효과적인 것으로 나타났다. 플라즈마를 단독으로 사용하여 휘발성유기화합물을 분해할 경우 타르형태의 생성물이 반응기에 퇴적되는 문제점이 있으나, 플라즈마-촉매 공정에서는 이러한 현상이 관찰되지 않았으며 촉매의 활성이 그대로 유지되었다.

• 동력기계공학회지
• /
• 제18권6호
• /
• pp.29-33
• /
• 2014

The electrochemical characteristics of Al-Si casting alloys (Al-10%Si, Al-9%Si, Al-7%Si) in 3.5% NaCl solution at room temperature was studied using potentiodynamic techniques. The electrochemical values of corrosion potential($E_c$), corrosion current density($I_c$) and corrosion rate(mpy) were examined. The Al-Si alloys had several compounds such as $Mg_2Si$, ${\pi}$-$Al_8Si_6Mg_2Fe$ and $Al_2CuMg$ which could affect corrosion resistance significantly. The potentiodynamic polarization curve exhibited typical active behavior in anodic polarization curve. The major corrosion mechansim for the Al-Si alloys were pitting and grain boundary corrosion. As increasing Si and Cu contents, their corrosion resistance was decreased.

• Progress in Superconductivity
• /
• 제12권2호
• /
• pp.110-113
• /
• 2011

We have grown a Nb/Gd bilayer on a$SiO_2$/Si substrate by using a DC magnetron sputtering system, which was fabricated in situ with silicon stencil masks. In order to investigate proximity effect of the Nb/Gd bilayer, we used a planar tunnel junction with an AlOx tunnel barrier by oxidizing the Al ground electrode at the bottom. A $Co_{60}Fe_{40}$ backing of Al was deposited so as to reduce the superconductivity of the Al, ensuring a normal counterelectrode. With a 50-nm-thick Nb layer, we have measured dI/dV (dynamic conductance) by varying the thickness of Gd, which can reveal the density of states (DOS) of the Nb/Gd bilayer as a function of the Gd thickness resulting from the proximity effect of a superconductor/ferromagnet bilayer (S/F). The SF proximity effect in Nb/Gd will be discussed in comparison to our previous results of the CoFe/Nb, Ni/Nb and CuNi/Nb proximity effect; Gd is expected to show different effects since Gd has f-electrons, while CoFe, Ni, and CuNi have only d-electrons. Our studies will focus on the triplet correlation in a superconducting pair.

• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 1997년도 추계학술발표회논문집
• /
• pp.67-69
• /
• 1997

Abstract - In this paper, the behaviour and effect of various particles made of conducting wires( Fe, Cu, Al ) in a SF6 insulated electrode system, are presented. It is shown that the ac breakdown voltage of compressed SF6 is influenced by different conducting particles. The breakdown voltage due to the particle is dependent of a class of particle. The breakdown voltage due to Cu particle was the highest and the breakdown voltage due to Al particle was the lowest.

• 한국재료학회지
• /
• 제27권11호
• /
• pp.597-602
• /
• 2017

In this study, an Al-0.7wt%Fe-0.2wt%Mg-0.2wt%Cu-0.02wt%B alloy was designed to fabricate an aluminum alloy for electrical wire having both high strength and high conductivity. The designed Al alloy was processed by casting, extrusion and drawing processes. Especially, the drawing process was done by severe deformation of a rod with an initial diameter of 12 mm into a wire of 2 mm diameter; process was equivalent to an effective strain of 3.58, and the total reduction in area was 97 %. The drawn Al alloy wire was then annealed at various temperatures of 200 to $400^{\circ}C$ for 30 minutes. The mechanical properties, microstructural changes and electrical properties of the annealed specimens were investigated. As the annealing temperature increased, the tensile strength decreased and the elongation increased. Recovery or/and recrystallization occurred as annealing temperature increased, and complete recrystallization occurred at annealing temperatures over $300^{\circ}C$. Electric conductivity increased with increasing temperature up to $250^{\circ}C$, but no significant change was observed above $300^{\circ}C$. It is concluded that, from the viewpoint of the mechanical and electrical properties, the specimen annealed at $350^{\circ}C$ is the most suitable for the wire drawn Al alloy electrical wire.

• 한국대기환경학회지
• /
• 제15권2호
• /
• pp.191-199
• /
• 1999

This study evaluated the availability as an alternative adsorbent which is cheaper and more efficient than CuO/${\gamma}$-$Al_2O_3$ which have been studing vigorously to remove $SO_2$. Five adsorbents (CuO/${\gamma}$-$Al_2O_3$, Iron ore, Slag, LD slag, $Fe_2O_3$) was employed in a fixed bed reactor. $SO_2$ breakthrough curves were obtained as a function of temperature, initial gas velocity and particle size. Saturation capacities calculated by the numerical integration of breakthrough curves of $SO_2$ increased with increasing reaction temperature. $SO_2$ breakthrough curve equation of $Fe_2O_3$ for this system can be expressed as Kr=3,914,000 exp(-37,329.86/RT). By means of the breakthrough curve, the influence of bed height on breakthrough time was also estimated.