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La0.8Sr0.2 Mn1-yFeyO3微波电磁特性与损耗机制 总被引:17,自引:2,他引:17
用溶胶凝胶法制备La0.8Sr0.2Mn1-yFeyO3(y=0.10,0.12,0.14,0.16)样品,测试并分析该样品在2~18 GHz微波频率范围的复介电常数、复磁导率、损耗角正切及微波吸收系数与频率的关系,发现y=0.12,0.14时吸波的效果最好。样品厚度为2 mm、y为0.12时,有2个吸收峰,吸收峰值最高达22 dB,10 dB以上吸收频带宽度达6.2 GHz;厚度2.21 mm样品8 dB以上的吸收频宽达8.5 GHz。初步探讨了该材料的电磁损耗机理,电磁特性参数在频率为12.4 GHz位置发生阶跃式变化,在小于12.4 GHz频率范围以介电损耗为主,在大于12.4 GHz频率范围以磁损耗为主,这与Fe对Mn3 —O—Mn4 之间的影响有关。电导率测试表明在室温范围内电导在半导体范围内,有利于降低微波在氧化物表面的反射率。 相似文献
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纳米ZnO光催化降解有机物研究进展 总被引:1,自引:0,他引:1
简述了纳米ZnO的光催化机理、提高光催化性能的方法和影响光催化性能的环境因素;介绍了电场、微波等场耦合新型增效、助效技术的研究进展;并对未来的研究方向和工作重点提出了一些设想。 相似文献
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La0.8Ba0.2MnO3 nano-particles were synthesized by sol-gel process, and the crystal structure and morphology' were characterized by XRD and SEM, respectively. The complex permittivity and permeability were determined by microwave vector network analyzer in the frequency range of 2-18 GHz. The relationship between reflection coefficient and microwave frequency of La0.8Ba0.2 MnO3 was calculated based on measured data. The results show that the average diameter of La0.8Ba0.2MnO3 crystal powders is about 80 nm and the crystal structure is perovskite when being calcined at 800 ℃ for 2 h. The microwave absorbing peak is 13 dB at 6.7 GHz and the effective absorbing bandwidth above 10 dB reaches 1.8 GHz for the sample with the thickness of 2.6 mm. The microwave absorption can be attributed to both the dielectric loss and the magnetic loss from the loss tangents of the sample, but the former is greater than the latter. 相似文献
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