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        검색결과 2,678

        278.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Recently, the circular economy aiming at elimination of waste and the continual use of resources has attracted a lot of attentions. In the circular system, the resource recovery uses the recycled wastes as the raw material to manufacture new valuable products. This work focuses on a low-cost process, in which an activated carbon (AC) adsorbent was prepared from waste cation exchange resin by calcination and HNO3 activation hydrothermal method. Surface structure and chemistry of AC were characterized by SEM, XRD, FTIR and Boehm titration. It was found that the acid treatment could increase the number of pores and the content of oxygen-containing functional groups on AC surface. In the adsorption experiment, Methylene blue (MB) was used to assess the adsorption capacity of AC. Experimental results showed that the highest efficiency of MB removal was achieved by AC with modification of 4M HNO3, showing the acidification effect on the adsorption capacity of AC. Adsorption isotherms of Langmuir and Freundlich were employed to fit the experimental data. It was shown that MB adsorption on AC is more consistent with Langmuir model that assumes a homogeneous adsorption. In the adsorption kinetic analysis, the adsorption was found to follow the pseudo-second-order model, indicating that adsorption of MB on acidified AC is dominated by chemical adsorption. The study revealed that the waste ion-exchange resin is a proper precursor of carbon adsorbent for MB dye. This low-cost method would specifically reduce the environmental cost of waste disposal.
        4,600원
        279.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        분화국화 ‘솔라에그(등록번호 8569)’는 2015년 경상남도농 업기술원 화훼연구소에서 분홍색 ‘포인트에그’를 감마선 처리 를 하여 육성하였다. 특성검정과 형질 안정성은 2017년에서 2018년까지 3회를 수행하였다. ‘솔라에그’는 분홍색 꽃잎(54D) 과 적자색 중심부(59B)를 가진 ‘아네모네’ 형태이다. 꽃과 잎 색깔과 모양에서는 ‘솔라에그’와 ‘포인트에그’ 간의 차이는 거 의 없었다. ‘솔라에그’의 식물체와 개화 연구에서 조명과 억제 재배를 했을 때 약 42일로 개화소요시간은 비슷했다. 그러나 초장, 꽃 크기, 꽃 중심부 크기와 착화수에서 ‘포인트에그’와 비교했을 때 차이가 있었다. 특히, 자연재배조건에서 꽃 크기 는 4cm으로 대조품종과 비교했을 때 컸다. 국화 품종에서는 꽃의 크기가 상업적으로 중요한 형질이다. ‘솔라에그’의 표현 형과 개화기 연구와 비교하여 배수성, RAPD, 세포 크기 및 수 분석을 하였다. 이들 결과에서는 표현형의 변화는 작은 유전 적 변이와 세포 분열 증가와 관련이 있을 것이라고 추정하고 있다. 중형 크기의 ‘솔라에그’는 분화국화로 이용되며 농가의 평균소득 증대를 기대할 수 있다.
        4,000원
        280.
        2022.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Reheat treatment process of mold is necessary when partial machining of the mold is required, such as shape correction for an existing mold. If defects such as cracks or significant deterioration of mechanical properties of the mold occur during reheat treatment, it is impossible to reuse the mold. In this study, reheat treatment was performed up to two times for STD11 tool steel, and microstructure and mechanical properties according to the reheat treatment were evaluated. Carbide fraction and grain size of prior austenite were almost unchanged after the reheat treatment. Hardness and impact toughness increased significantly after QT treatment, and these properties were maintained without significant change even after the reheat treatment. It is concluded that up to two iterations of reheat treatment does not cause deterioration of properties of STD11 tool steel. Based on these results, a mold for a face-lifted front bumper was manufactured through machining and reheat-treating of an existing mold.
        4,000원