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        검색결과 7

        1.
        2022.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        There is ongoing research to develop lithium ion batteries as sustainable energy sources. Because of safety problems, solid state batteries, where electrolytes are replaced with solids, are attracting attention. Sulfide electrolytes, with a high ion conductivity of 103 S/cm or more, have the highest potential performance, but the price of the main materials is high. This study investigated lithium hydride materials, which offer economic advantages and low density. To analyze the change in ion conductivity in polymer electrolyte composites, PVDF, a representative polymer substance was used at a certain mass ratio. XRD, SEM, and BET were performed for metallurgical analyses of the materials, and ion conductivity was calculated through the EIS method. In addition, thermal conductivity was measured to analyze thermal stability, which is a major parameter of lithium ion batteries. As a result, the ion conductivity of LiH was found to be 106 S/cm, and the ion conductivity further decreased as the PVDF ratio increased when the composite was formed.
        4,000원
        2.
        2011.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        La doped CuO-ZnO-Al2O3 powders are prepared by sol-gel method with aluminum isopropoxide and primarydistilled water as precursor and solvent. In this synthesized process, the obtained metal oxides caused the precursor such ascopper (II) nitrate hydrate and zinc (II) nitrate hexahydrate were added. To improve the surface areas of La doped CuO-ZnO-Al2O3 powder, sorbitan (z)-mono-9-octadecenoate (Span 80) was added. The synthesized powder was calcined at varioustemperatures. The dopant was found to affect the surface area and particle size of the mixed oxide, in conjunction with thecalcined temperature. The structural analysis and textual properties of the synthesized powder were measured with an X-rayDiffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller surface analysis (BET),Thermogravimetry-Differential Thermal analysis (TG/DTA), 27Al solid state Nuclear Magnetic Resonance (NMR) and transforminfrared microspectroscopy (FT-IR). An increase of surface area with Span 80 was observed on La doped CuO-ZnO-Al2O3powders from 25m2/g to 41m2/g.
        4,000원
        3.
        2010.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The hydrogen energy had recognized clean and high efficiency energy source. The research field of hydrogen energy was production, storage, application and transport. The commercial storage method was using high pressure tanks but it was not safety. However metal hydride was very safety due to high chemical stability. Mg and Mg alloys are attractive as hydrogen storage materials because of their lightweight and high absorption capacity (about 7.6 wt%). Their range of applications could be further extended if their hydrogenation properties and degradation behavior could be improved. The main emphasis of this study was to find an economical manufacturing method for Mg-Ti-Ni-H systems, and to investigate their hydrogenation properties. In order to examine their hydrogenation behavior, a Sievert's type automatic pressure-compositionisotherm (PCI) apparatus was used and experiments were performed at 423, 473, 523, 573, 623 and 673 K. The results of the thermogravimetric analysis (TGA) revealed that the absorbed hydrogen contents were around 2.5wt.% for (Mg8Ti2)-10 wt.%Ni. With an increasing Ni content, the absorbed hydrogen content decreased to 1.7 wt%, whereas the dehydriding starting temperatures were lowered by some 70-100 K. The results of PCI on (Mg8Ti2)-20 wt.%Ni showed that its hydrogen capacity was around 5.5 wt% and its reversible capacity and plateau pressure were also excellent at 623 K and 673 K.
        4,000원
        4.
        2010.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Al2O3 has received wide attention with established use as a catalyst and growing application in structural or functional ceramic materials. On the other hand, the boehmite (AlO(OH)) obtained by sol-gel process has exhibited a decrease in surface area during phase transformation due to a decline in surface active site at high temperature. In this work, Al2O3-CuO/ZnO (ACZ) and Al2O3-CuO/CeO (ACC) composite materials were synthesized with aluminum isopropoxide, copper (II) nitrate hemi (pentahydrate), and cerium (III) nitrate hexahydrate or zinc (II) nitrate hexahydrate. Moreover, the Span 80 as the template block copolymer was added to the ACZ/ACC composition to make nano size particles and to keep increasing the surface area. The ACZ/ACC synthesized powders were characterized by Thermogravimetry-Differential Thermal analysis (TG/DTA), X-ray Diffractometer (XRD), Field-Emmision Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller (BET) surface analysis and thermal electrical conductivity (ZEM-2:M8/L). An enhancement of surface area with the addition to Span 80 surfactant was observed in the ACZ powders from 105 m2/g to 142 m2/g, and the ACC powders from 103 m2/g to 140 m2/g, respectively.
        4,000원