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        검색결과 1,407

        202.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of heat treatment and vacuum conditions on the textural properties and electrochemical performance of commercially available activated carbons (ACs) was investigated. The AC after post-heat treatment was characterized by nitrogen adsorption–desorption, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy measurements. The ACs treated under vacuum conditions exhibit a higher specific surface area and micropore surface area than those treated under nitrogen atmospheric pressure without significantly affecting the graphite structure of the AC. Under 800 °C temperature and vacuum conditions (AC-V800), the AC with the highest Brunauer– Emmett–Teller surface area of 1951.9 m2 g−1 (16.4% improvement relative to that of the original AC (1677.2 m2 g−1)) was obtained. This is attributed to the removal of oxygen-containing functional groups and volatile matters in the carbon by thermal treatment under vacuum conditions. Consequently, the electric double-layer capacitor using ACs treated under vacuum conditions (1 kPa) at 800 °C (AC-V800) shows considerably improved electrochemical performance in terms of higher specific capacitance and better cycling stability at a high working voltage (3.1 V), compared to the nitrogen-treated and commercial ACs.
        4,300원
        204.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to develop an environmentally friendly horticultural substrate that promotes the growth of organic onion(Allium cepa L.) seedlings. Four substrates were prepared by mixing different ratios of peatmoss, cocopeat, perlite, vermiculite, and zeolite. Their pH and electrical conductivities ranged from 5.12 to 5.60 and from 0.07 to 0.08 dS/m, respectively. Beneficial microorganisms, molasses, sesame oil cake, and sulfur were added to one substrate combination, which was named “environmentally friendly horticultural substrate” (EFHS). The chemical properties of the EFHS were analyzed and compared with a commercial organic horticultural substrate (OHS) and a commercial general horticultural substrate (GHS). The organic matter and inorganic ion (nitrogen, potassium, calcium, zinc, and sulfur) contents in the EFHS were higher than those in the OHS and GHS. The germination rates of onion seeds in the EFHS were higher than in the OHS and GHS. The mean number of leaves, sheath diameter per seedling, and weight of 30-day-old seedlings grown on the EFHS were greater than those of seedlings grown on the OHS and GHS. The length of the seedlings grown on the EFHS was comparable to that of the seedlings grown on the OHS and greater than that of the seedlings grown on the GHS. Overall, the growth parameters of onion seedlings grown on the EFHS were better than those of seedlings grown on the OHS and GHS, suggesting that the EFHS may be used as an organic horticultural substrate for growing organic onion seedlings.
        4,000원
        218.
        2021.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        For application in nuclear decommissioning, underwater laser cutting studies were conducted on thick stainless-steel plates for various cutting directions using a 6 kW fiber laser. For cutting along the horizontal direction with horizontal laser irradiation, the maximum cutting speed was 110 mm∙min−1 for a 48 mm thick stainless-steel plate. For cutting along the vertical direction with horizontal laser irradiation, a maximum speed of 120 mm∙min−1 was obtained for the same thickness, which confirmed that the cutting performance was similar but slightly better. Moreover, when cutting with vertically downward laser irradiation, the maximum cutting speed was 120 mm∙min−1 for a plate of the same thickness. Thus, the cutting performance for vertical irradiation was nearly identical to that for horizontal irradiation. In conclusion, it was possible to cut thick stainless-steel plates regardless of the laser irradiation and cutting directions, although the assist gas rose up due to buoyancy. These observations are expected to benefit laser cutting procedures during the actual dismantling of nuclear facilities.
        4,000원
        219.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 본 연구는 베트남 쌀 농장의 농업 기계화 서비스 제공의 재무 성과를 분석하였다. 2. 2014년 베트남 가계생활수준조사 결과를 활용하여 타 농가의 쌀 생산에 농업 기계화 서비스를 제공한 164명의 농가를 추출하였으며, 분석한 결과 해당 서비스의 제공이 농가당 약 1700 만 VND / 년의 수익을 발생시켰다는 것이 발견되었다. 3. 자산 감가 상각, 노동 아웃소싱, 농업 신용 및 쌀 토지 면적의 경우 그 값이 커질 수록 농업 서비스 제공자의 재정 효율성을 저하시키는 것으로 발견되었다. 4. 한편, 남성이거나 주 수입이 쌀 생산인 농부들은 재정적 효율성이 더 높은 것으로 분석되었다. 5. 본 연구는 베트남 농민들이 쌀 생산의 재정적 효율성 향 상에 농업 기계화가 긍정적인 영향을 주고 있음을 시사하지만, 농업 기계의 짧은 운용시간을 고려하였을 때 농업 기계 구입을 위한 신용 대출 정책에 있어 베트남 정부가 신중하게 접근할 필요가 있음을 제시하고 있다.
        4,000원
        220.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Intercropping cereals with legumes is known to improve forage production and crude protein yield. Sorghum × sudangrass hybrids (SSH) have excellent dry matter content and high cultivation temperatures. In this study, we investigated the growth characteristics, forage productivity, and feed value of intercropping SSH with different legumes in rice paddy fields. We used five treatments in this study SSH monocropping and four intercropping treatments of SSH with, lablab, cowpea, sesbania, and two cultivars of soybean (Chookdu 1 and 2). SSH plant height was not significantly different between the monocropping and intercropping treatments. However, the plant heights of lablab, cowpea, and sesbania were significantly higher than those of the two soybean cultivars. The total dry matter yield (kg/ha) was significantly higher in SSH monocropping than in intercropping; among the intercropping treatments, the one with SSH and Chookdu 2 yielded the highest total dry matter yield. The SSH feed value was significantly different between the monocropping and intercropping treatments, although there were no differences between the intercropping treatments. Among the intercropped legumes, lablab showed the highest neutral detergent fiber and acid detergent fiber contents, and cowpea had the highest crude protein content. These results reveal that intercropping SSH with legumes in paddy fields could be a promising cultivation technique to maintain stable forage productivity.
        4,000원