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        검색결과 174

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate the effects of amino acid complex additives, such as protected vitamin C (VC) or detoxified sulfur (DS), on the growth and metabolism of Hanwoo cattle under high-temperature conditions. Accordingly, farms in Temperature-Humidity Index (THI) regions ranging from 78 to 89 for over 100 days were selected. The experimental groups were control, T1 (lysine + methionine + VC, 50 g/head/day), and T2 (lysine + methionine + DS, 50 g/head/day) with 70, 77, and 71 animals each. The range of the THI for 115 days was 78-89, and this occurred in most of the experiment days. The results showed that there was no significant difference in rectal temperature among the groups. The body weight increased to 786.4 and 809.0kg in the T1 and T2 groups, respectively, compared to the control group (p<0.05). Linoleic acid showed a high result of 2.01% in the T1 group compared to the control group (p<0.05). Unsaturated fatty acids were higher at 55.70 and 56.54% in the T1 and T2 groups, respectively, compared to the control group (p<0.05), and the omega 6/3 ratio was reduced to 20.10% (p<0.05). These findings indicate that T1 has a positive impact on growth, meat quality, and fatty acid composition compared to the control group. In conclusion, amino acid complex with VC improved the body weight of Hanwoo steers and the unsaturated fatty acids and essential amino acids of their meat; however, further research is needed to clarify this impact on carcass performance.
        4,800원
        2.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Radish is a sulfur-containing compound containing the -S group, having bioactive functions such as anticancer, antithrombotic, antioxidant, and antibacterial properties, and is used as a health supplement and pharmaceutical material. This study aimed to compare changes in sulforaphane (SFN) content according to freeze-drying or hot-air drying conditions in Korean radishes. The color of frozen or hot-air-dried radish underwent a browning reaction due to heat treatment; the brightness (L) decreased from 89.3 to 56.1, and the redness (b) increased. The SFN content of freezedried radish was 13.2565 mg/g, the SFN of radish dried at 50oC was 2.64372 mg/g, and the SFN of radish dried at 80oC was 0.0678 mg/g, which was the highest in freeze-dried radish. Therefore, the SFN of radish was found to be insufficient in thermal stability, and freeze-drying was considered a suitable method for drying radish.
        4,000원
        3.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The development of functional carbon materials using waste biomass as raw materials is one of the research hotspots of lithium-sulfur batteries in recent years. In this work, used a natural high-quality carbon source—coffee grounds, which contain more than 58% carbon and less than 1% ash. Honeycomb-like S and N dual-doped graded porous carbon (SNHPC) was successfully prepared by hydrothermal carbonization and chemical activation, and the amount of thiourea used in the activation process was investigated. The prepared SNHPC showed excellent electrochemical energy storage characteristics. For example, SNHPC-2 has a large pore volume (1.85 cm3·g− 1), a high mesoporous ratio (36.76%), and a synergistic effect (S, N interaction). As the cathode material of lithium-sulfur batteries, SNHPC-2/S (sulfur content is 71.61%) has the highest specific capacity. Its initial discharge-specific capacity at 0.2 C is 1106.7 mAh·g−1, and its discharge-specific capacity after 200 cycles is still as high as 636.5 mAh·g−1.
        4,600원
        6.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Here, we have demonstrated the successful exfoliation of graphite into a layered material with scotch tape-like exfoliation. Sulfur acts as an exfoliating agent and exfoliates the loosely bounded graphite stacks. The shear force by ball milling provides the force required to overcome the van der Waals force between the layers. The MnO2 nanorods were synthesized using a KMnO4 precursor in a hydrothermal arrangement, and due to their intrinsic chemisorption capability, they were doped for polysulfide trapping. With an initial capacity of 1150 mAh/g achieved by the MnO2 nanorod-doped exfoliate-graphite/sulfur composite material, the material has displayed its application in lithium–sulfur batteries, but its use is not limited; it can be a low-cost eco-friendly solution to various energy storage systems with extensive structural qualities.
        4,000원
        7.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sulfur is an essential element in plants, including amino acids, vitamin synthesis, and acting as an antioxidant. However, the interaction between endogenous sulfur and proline synthesis has not been yet fully documented. White clover (Trifolium repens L.) is known as a species highly sensitive to sulfate supply. Therefore, this study aimed to elucidate the role of sulfur in regulating proline metabolism in relation to ammonia detoxification and hydrogen peroxide (H2O2) accumulation in white clover. The detached leaves of white clover were immersed in solution containing different concentration of sulfate (0, 10, 100, and 1000 mM MgSO4). As MgSO4 concentrations were increased, the concentration of H2O2 increased up to 2.5-fold compared to control, accompanied with H2O2 detection in leaves. Amino acid concentrations significantly increased only at higher levels (100 and 1000 mM MgSO4). No significant difference was observed in protein concentration. Proline and Δ1-pyrroline-5-carboxylate (P5C) concentrations slightly decreased at 10 and 100 mM MgSO4 treatments, whereas it rapidly increased over 1.9-fold at 1000 mM MgSO4 treatment. Ammonia concentrations gradually increased up to 8.6-fold. These results indicate that exogenous sulfur levels are closely related to H2O2 and ammonia synthesis but affect proline biosynthesis only at a higher level.
        4,000원
        8.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the biological activity of fucoidan, a sulfur-containing polysaccharide, on cytotoxicity and apoptosis in the human HT-29 colorectal cancer cell line using cell viability, Flow cytometry, Western blot, and RT-PCR analyses. Fucoidan inhibited the proliferation of HT-29 cells by 39.6% at a concentration of 100 μg/mL for 72 h. The inhibition was dose-dependent and accompanied by apoptosis. Flow cytometric analysis showed that fucoidan increased early apoptosis and late apoptosis by 65.84% and 72.09% at concentrations of 25 and 100 μg/mL, respectively. Analysis of the mechanism of these events indicated that fucoidan-treated cells exhibited increases in the activation of caspase-3, caspase-8, and PARP in a dose-dependent manner. These results suggest that fucoidan may inhibit the growth of human colorectal cancer cells by various apoptosis-promoting effects, as well as by apoptosis itself.
        4,000원
        9.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 강화되는 황산화물 및 입자상물질의 배출규제를 만족시키기 위한 후처리장치로 습식전기집진기에 대한 실험적 연구를 수행하였다. 실험을 위해 선박용 중유(HFO, 황함유량 약 2.1%)를 연료로 사용하는 선박용 4행정 디젤엔진(STX-MAN B&W)을 활용 하였으며, 연돌에 설치된 습식전기집진기 입/출구에서 측정을 실시하였다. 미세먼지 측정을 위해서는 광학식 계측기(OPA-102) 및 중량농 도측정방식(Method 5 Isokinetic Train)을 이용하였으며, 황산화물 계측을 위해서는 FT-IR(DX-4000)을 사용하였다. 엔진부하는 50%, 75%, 100%로 변화시키면서 실험을 실시하였다. 실험 결과로, 엔진부하가 50%에서 100%로 변화함에 따라 미세먼지 저감 효율은 모든 부하 조건에서 94~98% 정도의 높은 저감 효율을 나타내었다. 추가적으로 습식전기집진기 퀜칭존에서 배기가스의 온도를 낮추는 과정 중 세정액에 의한 이산화황(SO2) 저감을 확인할 수 있었으며, 저감율은 엔진부하에 따라 55%~81%로 확인되었다.
        4,000원
        10.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The International Maritime Organization(IMO)는 2020년 1월 1일부터 국제항해 선박에 사용되는 모든 연료의 황분을 0.5 % 이하로 제한하고 있다. 연료유 황 함유량 규제 대응을 위해 LNG 선박, SOx scrubbers, 저유황유(Very Low-Sulfur Fuel Oil, VLSFO) 사용 등이 고려되고 있으며, 이 중 투자비용이 상대적으로 적은 저유황유가 선호되고 있다. 따라서 저유황유를 사용하는 선박이 증가함에 따라 오염사고 위험성이 높아질 것으로 예상된다. 특히, 해수 온도가 저유황유의 유동점 이하로 유출될 경우 고형화됨에 따라 방제에 어려움을 겪고 있는 사례도 나타나고 있다. 본 논문에서는 국내서 생산되는 저유황유 6종과 고유황유(MF380) 1종에 대해 해수 온도 조건에 따라 유처리제의 분산 능력을 평가하였다. 연구결과, 저유황유는 국내 기준(0.5 min 정치 60 % 이상, 10 min 정치 20 % 이상)을 만족하지 못했으며, 고유황유에 비해 상대적으로 낮은 유화율을 보였다. 본 연구결과는 저유황유가 해상에 유출될 경우, 방제방향을 설정하는 데 활용될 수 있을 것으로 기대된다.
        4,000원
        11.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국제해사기구(IMO)의 황함유량 규제에 따르는 저유황연료유는 생산 공정에 따라 다양한 물리화학적 특성을 가지게 된다. 본 연구는 저유황연료유 및 저유황-고유황 혼합연료유의 물리화학적 특성연구 결과를 해양오염 방제대응의 기초자료로 활용하고자 한다. 연구에 사용된 혼합연료유는 황함유량이 0.46 mass%인 저유황연료유와 0.36 mass%인 저유황연료유에 고유황연료유를 25, 50, 75 mass% 혼합하여 제조하였다. 이 혼합연료유에 대해 동점도, 유동점 및 Saturates, Aromatics, Resins, Asphaltenes(SARA)분포 등 물리화학적 특성에 대해 실험실 연구를 하였다. 동점도가 높고 유동점이 낮은 특징의 고유황연료유가 75 mass% 혼합함에 따라, 혼합연료유의 동점도는 350.2 %까지 증가 하였으며, 유동점이 23℃와 -11℃의 저유황연료유는 각각 -3℃ 및 -6℃까지 유동점이 내려가거나 올라갔다. Asphaltenes 분포가 적은 저유황연료유에 고유황연료유를 혼합함에 따라, Saturates분포는 68.8 %까지 감소하고, Asphaltenes분포는 1,417 %까지 크게 증가하였다.
        4,000원
        16.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근, L형 도로측구 상 열화, 균열로 인한 유지보수 작업이 빈번해지고 있다. 본 논문에서는 쐐기 앵커를 이용한 L형 도로측구의 최적 설계에 대해 제시하고자 하였다. 해석 결과, 두 개의 쐐기앵커를 350mm로 관입시킨 경우에서 구조적 안정성을 충분히 확보하는 것을 확인하였다. 또한 3%의 개질유황 콘크리트 배합이 압축강도, 동결융해 등의 내구성 기준을 만족하였다. 반복하중에 대한 수치해석과 현장 평가가 수행 중에 있으며, 추후 해당 시스템의 적용성을 평가하기 위한 추적 조사가 이루어져야 할 것이다.
        4,000원
        17.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We reported the synthesis of dendrite-like carbon nanotube-confined polymeric sulfur composite by modifying the surface of carbon nanotubes (CNTs) with trithiocyanuric acid (TTCA) and then copolymerizing with sulfur. DSC results show the successfully formation of robust chemical bonds between sulfur and TTCA modified CNTs, which effectively avoid the dissolution of polysulfide when used as cathodes for lithium–sulfur batteries. The composite with a high sulfur content of 78 wt% exhibits an initial charge capacity of 698 mAh g− 1 and the residual capacity of 553 mAh g− 1 after 1000 cycles at a rate of 1 C.
        4,000원
        18.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Giant miscanthus (GM) is an Asian grass that can produce biomass in high yields per land area. It can be used as a cathode material in lithium sulfur (Li/S) batteries. Giant-miscanthus-derived activated carbon (GMAC) is prepared via carbonization of GM followed by KOH activation. It is prepared with a large amount of KOH, and thus contained more defects but had a highly porous structure and graphitic cluster lattice. GMAC has a large specific surface area of 3327 m2/g and a large total pore volume of 1.86 cm3/g. The pore volume served as a storage space for the retention of polysulfides, thereby inhibiting the shuttle effect. When a GMAC–sulfur composite cathode is tested in a Li/S battery, an initial discharge capacity of 1148 mAh/g can be attained at 0.1 C. In a cyclic charge–discharge experiment at 1 C, discharge capacities of 529 mAh/g and 248 mAh/g are observed in the first and 200th cycles, respectively.
        4,000원
        19.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cadmium (Cd) toxicity is a serious limitation for agricultural production. In this study, we explored tolerance mechanism associated with Cd toxicity tolerance in alfalfa plants. We used three distinct alfalfa cultivars M. sativa cv. Vernal, M. sativa cv. Zhung Mu, and M. sativa cv. Xing Jiang Daye in this study. Cd showed declined chlorophyll score in Xing Jiang Daye compared with Zhung Mu and Vernal. No significant change observed among the cultivars for root and shoot length. Atomic absorption spectroscopy analysis demonstrated a significant accumulation of Cd, Fe, S and PC in distinct alfalfa cultivars. However, Zhung Mu and Xing Jiang Daye declined Cd accumulation in root, where Fe, S and PC incremented only in Zhung Mu. It suggests that excess Cd in Zhung Mu possibly inhibited in root by the increased accumulation of Fe, S and PC. This was further confirmed by the response of Fe (MsIRT1) and S transporters (MsSULTR1;2 and MsSULTR1;3), and MsPCS1 genes associated with Fe, S and PC availability and translocation in roots and shoots. It suggests that specially the transcript signal inducing the responses to adjust Cd especially in Zhung Mu. This finding provides the essential background for further molecular breeding program for forage crops.
        4,000원
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