In order to improve the microwave absorbing properties of Nd Fe B alloys, as-jet milled powders were further processed in a planetary mill. The phase structure, morphology and particle size of the alloy powders were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM) and laser diffraction-based particle size analyzer, respectively. The saturation magnetization and electromagnetic parameters of the powders were determined by a vibrating sample magnetometer(VSM) and a vector network analyzer(VNA), respectively. The results showed that the saturation magnetization decreased as the milling time increased. The minimum absorption peak frequency shifted towards the lower region and the reflection loss values increased with increasing the ball milling time. The minimum absorption peak value of the powders milled for 15 h on the basis of jet milling reached –44.4 d B at 11.04 GHz, and the bandwidth of R<–10 d B was 1.2 GHz with the best matching thickness of 1.8 mm.
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机译:Fe3O4纳米微球、MWCNT/Fe3O4异质结构溶剂热制备和微波吸收性能 Solvothermal Synthesis and Microwave Absorbing Properties of Fe3O4Microspheres and MWCNT/Fe3O4Heterostructures
机译:How the Group Leaders of Lesson Preparation Groups Facilitate Group Learning and Reflective Practice in Chinese Public High Schools =中国公立高中的备课组长是如何引领团队学习和反思性实践的?