排序方式: 共有49条查询结果,搜索用时 578 毫秒
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花色苷是一种水溶性类黄酮物质,广泛分布于深色谷物、浆果及蔬菜中。花色苷具有较强的抗氧化和抗炎活性,摄入适量富含花色苷的谷物可降低患糖尿病、心血管疾病、年龄相关性黄斑变性等慢性病的风险。本文系统介绍了不同谷物来源的花色苷对慢性病的健康功效及作用机理,重点阐明花色苷在谷物中的分布与含量,对Nrf2、NF-κB、MAPK、PI3K/AKT等信号通路的调控作用机制,梳理了谷物花色苷的开发利用现状及发展趋势,为谷物花色苷在食品、药品等领域的基础研究及产品开发提供参考依据。 相似文献
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无压烧结制备Al2O3/SiC纳米复合陶瓷 总被引:2,自引:0,他引:2
用沉淀法包裹微米级SiC颗粒,通过常压、埋烧制备Al2O3/SiC纳米复合陶瓷。通过XRD、TG和SEM等分析了煅烧和烧结过程中相组成的变化、烧成收缩和显微结构。结果表明:利用SiC粉埋烧及碳粉制造还原气氛,含8wt%SiC(平均粒径为5mm)的复合粉末经800℃煅烧、成型,试样于1550℃,2h烧结,可制备Al2O3/SiC纳米复合陶瓷,其相对体积密度达95.2%,在烧结过程中由SiC氧化形成的无定形SiO2及与基质氧化铝反应形成的莫来石前躯体可大大促进烧结。 相似文献
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以工业中广泛使用的85氧化铝陶瓷原料粉为原料,加入纳米碳化硅,通过控制无压埋烧制备了85Al2O3/SiC纳米复合陶瓷,研究了其表面抛光行为,讨论了纳米碳化硅对复合陶瓷表面抛光性能的影响.结果表明,纳米复合陶瓷表现出显著优于基体材料的表面抛光响应,在同样的磨料尺寸下,复合陶瓷能够得到更好的表面抛光质量.SEM分析表明,纳米碳化硅的加入使材料的抛光去除机制发生了改变,由大范围的深层晶粒拔出变为小尺寸的浅层去除和塑性变形. 相似文献
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Surface Oxidation of Al2O3/SiC Nanocomposite: Phase Transformation and Microstructure 总被引:1,自引:0,他引:1
The surface oxidation behavior of pressureless sintered Al2O3/SiC nanocomposite was studied from 1000 to 1400 ℃ for more than 10 h in air. Weight gain during the process of heat treatment was measured by TG analysis. Phase transformation and microstructure changes of these specimens due to oxidation were investigated with X-ray diffraction (XRD), SEM and EDX technology. Thermogravimetric analysis show that the weight gain as a result of oxidation of SiC become significant above 1200 ℃. In the range of 1000~1300 ℃, the SiC grits are usually coated with a layer of amorphous silica after oxidation. Above 1300 ℃, the amorphous silica reacted with alumina matrix and formed mullite or crystallized into cristobalite. The rate of oxidation depends on the formation of dense cristobalite film. Large amount of needle-like mullite and alumina crystals are formed on the surface after oxidation at 1400 ℃. 相似文献
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