검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 9

        1.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Metal-additive manufacturing techniques, such as selective laser sintering (SLS), are increasingly utilized for new biomaterials, such as cobalt-chrome (Co-Cr). In this study, Co-Cr gas-atomized powders are used as charge materials for the SLS process. The aim is to understand the consolidation of Co-Cr alloy powder and characterization of samples sintered using SLS under various conditions. The results clearly suggest that besides the matrix phase, the second phase, which is attributed to pores and oxidation particles, is observed in the sintered specimens. The as-built samples exhibit completely different microstructural features compared with the casting or wrought products reported in the literature. The microstructure reveals melt pools, which represent the characteristics of the scanning direction, in particular, or of the SLS conditions, in general. It also exposes extremely fine grain sizes inside the melt pools, resulting in an enhancement in the hardness of the as-built products. Thus, the hardness values of the samples prepared by SLS under all parameter conditions used in this study are evidently higher than those of the casting products.
        4,000원
        2.
        2017.04 구독 인증기관·개인회원 무료
        Recently, fruit vinegar made from fruit wine has been famous due to its health function and nutrition. Therefore, there are many fruit vinegar products manufactured by major big food companies and small company as well as one person through the internet shopping mall. In this study, 4 type citrus fruits vinegar (grapefruit, tangerine, orange, lemon) were investigated to find out the quality of vinegar for consumers’ wise selection. Commercial vinegar which are commonly produced by fermenting mixture of brown rice vinegar with fruit extracts were analyzed that sugar content, pH, acidity, turbidity, DPPH assay, FRAP assay, TPC and manufacture method. Among all samples, 4 tangerine vinegar acidity were suit with standard quality (4~29%) by MFDS. pH scale of all vinegar was from 2.76 to 3.48 and lemon vinegar was lowest. Average sugar content (brix%) was lowest at tangerine vinegar as 17.4. In the DPPH radical scavenging activity, there was no significant difference at all samples. In the TPC study and FRAP assay, lemon vinegar showed the highest value, while grapefruit, tangerine, and orange vinegar were not significantly different. From the result, product type, and qualities and suitability as vinegar product of various citrus fruits vinegar were observed and it was found that although product name is ‘vinegar’, some vinegar products were not suit with standard quality (acidity%).
        3.
        2006.04 구독 인증기관·개인회원 무료
        Branched sulfonated poly(ether sulfone-ketone) copolymer was prepared with bisphenol A, 4,4-difluorobenzophenone, sulfonated chlorophenyl sulfone (40mole% of bisphenol A) and THPE (1,1,1-tris-p-hydroxyphenylethane). THPE was used 0.4 mol% of bisphenol A to synthesize branched copolymers. Organic-inorganic nano composite membranes were prepared with copolymer and a series of nanoparticles (20 nm, 4, 7 and 10 wt%). The composite membranes were cast from dimethylsulfoxide solutions. The films were converted from the salt to acid forms with dilute hydrochloric acid. The membranes were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Sorption experiments were conducted to observe the interaction of sulfonated polymers with water and methanol. Branched copolymer and nano composite membranes exhibit proton conductivities from to , water uptake from 52.9 to 62.4%, IEC from 0.81 to 1.21 meq/g and methanol diffusion coefficients from to .
        4.
        2006.04 구독 인증기관·개인회원 무료
        Novel bisphenol-based wholly aromatic poly(ether sulfone-ketone) copolymer containing pendant sulfonate groups were prepared by direct aromatic nucleophilic substitution polycondensation of 4,4-difluorobenzophenone, 2,2'-disodiumsulfonyl-4,4'-fluorophenylsulfone (40mole% of bisphenol A) and bisphenol A. Polymerization proceeded quantitatively to high molecular weight in N-methyl-2-pyrrolidinone at . Organic-inorganic composite membranes were obtained by mixing organic polymers with hydrophilic (ca. 20nm) obtained by sol-gel process. The polymer and a series of composite membranes were studied by FT-IR, , differential scanning calorimetry (DSC) and thermal stability. The proton conductivity as a function of temperature decreased as content increased, but methanol permeability decreased. The nano composite membranes were found to posse all requisite properties; Ion exchange capacity (1.2meq./g), glass transition temperatures , and low affinity towards methanol .
        5.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        6,300원
        6.
        1995.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        4,200원