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The ribbons of NdFeB/α-Fe composite alloy were prepared by melt spinning and post crystallizing technique.The element distri-butions and phase component of both surfaces of as-spun ribbons were measured by energy dispersive spectrometry (EDS) and X-ray diffrac-tion (XRD).Because of the centrifugation,a segregation of B,Fe,and Nd concentrations was observed at the cross section.After crystallizing annealing,the element concentration segregation still existed in the as-crystallized ribbons.Due to the segregation of B,Fe,and Nd,the B-rich phase was observed near the wheel side surface.The B-rich phase may deteriorate the magnetic property of NdFeB/α-Fe composite alloy. 相似文献
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为提高鱼油稳定性,以青鱼内脏鱼油为芯材,大豆分离蛋白(SPI)和壳聚糖(CS)为壁材,制备鱼油微胶囊。采用单因素实验考察了均质速度、pH、壁材总质量分数、SPI/CS比值、芯壁比等因素对鱼油微胶囊制备效果的影响,结合响应面法优化鱼油微胶囊制备工艺,并比较研究了鱼油微胶囊湿囊分别经喷雾干燥和冷冻干燥两种干燥方法所得产品的包埋率、水分含量、贮藏稳定性。结果表明,最佳鱼油微胶囊制备工艺条件为:pH7、壁材总质量分数2%、SPI/CS比值1.3∶1、芯壁比1.3∶1,在此条件下鱼油包埋率为71.98%±0.16%。喷雾干燥法表面含油率为0.73%±0.04%,低于冷冻干燥法3.62%±0.09%,包埋率为71.98%±0.16%,高于冷冻干燥法56.76%±0.37%,说明喷雾干燥法效果优于冷冻干燥法,鱼油微胶囊贮藏期可较未包埋的鱼油延长6 d以上。通过微胶囊化,改善了青鱼内脏鱼油的性能,提高了使用范围和应用价值。 相似文献
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分析了谐波对各种电气设备的危害,阐述了谐波谐振的危害.针对谐波及谐波谐振过电压的危害提出了预防和应对措施。 相似文献