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        검색결과 6

        1.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        All-solid-state lithium batteries (ASSLBs) are receiving attention as a prospective next-generation secondary battery technology that can reduce the risk of commercial lithium-ion batteries by replacing flammable organic liquid electrolytes with non-flammable solid electrolytes. The practical application of ASSLBs requires developing robust solid electrolytes that possess ionic conductivity at room temperature on a par with that of organic liquids. These solid electrolytes must also be thermally and chemically stable, as well as compatible with electrode materials. Inorganic solid electrolytes, including oxide and sulfide-based compounds, are being studied as promising future candidates for ASSLBs due to their higher ionic conductivity and thermal stability than polymer electrolytes. Here, we present the challenges currently facing the development of oxide and sulfide-based solid electrolytes, as well as the research efforts underway aiming to resolve these challenges.
        4,000원
        2.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Li1.5Al0.5Ti1.5(PO4)3 (LATP) is considered to be one of the promising solid-state electrolytes owing to its excellent chemical and thermal stability, wide potential range (~5.0 V), and high ionic conductivity (~10-4 S/cm). LATP powders are typically prepared via the sol-gel method by adding and mixing nitrate or alkoxide precursors with chelating agents. Here, the thermal properties, crystallinity, density, particle size, and distribution of LATP powders based on chelating agents (citric acid, acetylacetone, EDTA) are compared to find the optimal conditions for densely sintered LATP with high purity. In addition, the three types of LATP powders are utilized to prepare sintered solid electrolytes and observe the microstructure changes during the sintering process. The pyrolysis onset temperature and crystallization temperature of the powder samples are in the order AC-LATP > CA-LATP > ED-LATP, and the LATP powder utilizing citric acid exhibits the highest purity, as no secondary phase other than LiTi2PO4 phase is observed. LATP with citric acid and acetylacetone has a value close to the theoretical density (2.8 g/cm3) after sintering. In comparison, LATP with EDTA has a low sintered density (2.2 g/cm3) because of the generation of many pores after sintering.
        4,000원
        3.
        2023.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Li1.3Al0.3Ti1.7(PO4)3(LATP) is considered a promising material for all-solid-state lithium batteries owing to its high moisture stability, wide potential window (~6 V), and relatively high ion conductivity (10-3–10-4 S/cm). Solid electrolytes based on LATP are manufactured via sintering, using LATP powder as the starting material. The properties of the starting materials depend on the synthesis conditions, which affect the microstructure and ionic conductivity of the solid electrolytes. In this study, we synthesize the LATP powder using sol-gel and co-precipitation methods and characterize the physical properties of powder, such as size, shape, and crystallinity. In addition, we have prepared a disc-shaped LATP solid electrolyte using LATP powder as the starting material. In addition, X-ray diffraction, scanning electron microscopy, and electrochemical impedance spectroscopic measurements are conducted to analyze the grain size, microstructures, and ion conduction properties. These results indicate that the synthesis conditions of the powder are a crucial factor in creating microstructures and affecting the conduction properties of lithium ions in solid electrolytes.
        4,000원
        4.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Ministry of Agriculture, Food and Rural Affairs introduced the Agrifood Voucher in 2020. The Agrifood Voucher is the program that provides vouchers to purchase selected food items with dietary management education. This study aimed to explore value and meaning of dietary management based on the Agrifood Voucher. First, the Supplemental Nutrition Assistance Program of the United States and the Agrifood Voucher of Korea were reviewed. Second, various terms used for describing the purpose of food assistance programs were comparatively reviewed and ‘food and nutrition security’, together with the corresponding Korean term, was proposed to be the most appropriate term for the purpose. Subsequently, the value and meaning of dietary management based on the Agrifood Voucher were presented as enhancing food and nutrition security of the vulnerable. Diverse education programs should be developed and implemented to improve the dietary management capacity of the Agrifood Voucher recipients in order to properly realize the meaning and value of dietary management based on the Agrifood Voucher in the future.
        4,000원
        5.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        니트로사민은 산성이나 열을 가했을 때 2급 아민과 질 소산화물이 반응해서 생성되는 발암물질이다. 일반적으로 위해 물질에 대한 안전성평가는 그 노출량을 mg/kg body weight/day로 산출하여 독성기준치와 비교하는 방법을 사용한다. 이런 방법은 정책 근거자료로는 적합하나 소비자 들에게 식생활 정보로 제공하기에 미진한 부분이 있다. 따라서 주재료 및 조리법으로 분류한 음식군에 대한 NDMA (N-nitrosodimethylamine), NDBA (N-nitrosodibutylamine) 및 6종 니트로사민(NDMA, NDBA, NDEA (N-nitrosodiethylamine), NPYR (N-nitrosopyrrolidine), NPIP (N-nitrosopiperidine), NMOR (N-nitrosomorpholine) 함량 분포를 파악하여 식습관 교육에 도움을 주고자 본 연구를 실시하였 다. 2014~2016년 국민건강영양조사 24시간 회상법 자료를 사용하여 만 7세 이상을 연구 대상으로 음식별 레시피와 섭취량을 추출하였고, 2013~2015년 총식이조사 원자료를 바탕으로 음식 한끼니 제공량 내 니트로사민 함량 분포를 R프로그램으로 산출하였다. 볼락, 장어, 멸치 육수, 명태 등의 기여로 어패류 및 해조류를 주재료로 한 음식군은 섭취량과 상관없이 NDMA, NDBA 및 총 6종 니트로사민 모두에 대한 노출을 높이는 것으로 나타났다. 또한 조리법에 따른 분류에서는 국 및 탕류와 찌개 및 전골류가 가 장 크게 노출에 기여하는 것으로 나타났다. 곡류, 과실류 및 유제품류 주재료 음식군, 밥류 및 밥 외의 다른 재료를 부가한 음식군들의 니트로사민 노출에 대한 기여도는 매우 낮은 것으로 나타났다. 니트로사민의 경우 조리시 생 성되는 여타 화합물과는 달리 국, 탕, 찌개, 전골 등 끓임을 주로 하는 음식과 어패류를 주재료로 하는 음식에서의 기여율이 매우 높은 것으로 나타났으며, 이는 기존에 가공육류를 니트로사민의 주노출원으로 생각하던 것과는 매우 큰 차이를 보인다.
        4,000원
        6.
        2018.05 서비스 종료(열람 제한)
        Background : Sea buckthorn (Hippophae rhamnoides) is a multipurpose small tree with unique berries of high nutritional and pharmaceutical values has wide spread distribution from Eurasia to South east Asia. In recent times the medicinal benefits of vitamin tree are inclining, hence, efforts were taken to propagate them in vitro to exploit their medicinal property. Methods and Results : The tissue culture potential of them was investigated for the ability to induce shoot organogenesis in leaf explant, and induction of direct somatic embryogenesis from leaf tissue. Moreover, we also determined the effective induction medium for callus and somatic embryo production from H. rhamnoides. To induce the callus form leaf tissue, several phytohormone combinations such as α-naphthalene acetic acid (NAA) and 6-benzyladenine (BA), 2,4-Dichlorophenoxyacetic acid (2,4-D) and 6-benzyladenine (BA), and Kinetin (K) were tried with the Murashige and Skoog (MS) as well as woody plant medium (WPM). In MS basal medium, the combination of 2,4-D and K showed the best callus induction rate of 71%, whereas in WPM basal medium the combination of NAA and BA showed the best callus induction rate of 91%. The adventitious root induction form callus was also attempted by using MS and B5 medium with the phytohormone combinations of IBA 1 – 5 g/ℓ. In MS medium, root was induced only at 4 g/ℓ of IBA and 64%, 51% and 55% root induction results were obtained at 3 g/ℓ, 4 g/ℓ and 5 g/ℓ in B5 basal medium, respectively. The somatic embryos were induced only in half strength MS with the triple phytohormone ratio of 2:1:2 of NAA, BA, and K. Conclusion : The in vitro propagation of sea buckthorn was successfully employed by generating callus, adventitious roots as well as the induction of somatic embryos form the leaf tissues derived callus. Our results provided a valuable addition to the utilization of H. rhamnoides thus enabling their propagation.