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The preparation and microwave-absorbing behavior of micrometric silica-modified platelet iron particles (SMPLIP) were investigated. Through precipitation, hydrothermal reaction, silica-modification and reduction with hydrogen, micrometric porous SMPLIP were yielded. The permittivity values of SMPLIP had been significantly decreased due to the presence of silica. Measurements and calculations showed that a 1.93mm thick sample containing SMPLIP as much as 60% by weight was capable of absorbing X band(8.2~12.4GHz) microwaves with reflection loss being greater than -10dB within the frequency range of 8.2~11.36GHz, while the maximum re-flection loss was -14.8dB at 9.4GHz. The results had also shown that it was practicable to prepare thin, light-weight microwave absorbent with SMPLIP. 相似文献
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替代M-型钡铁氧体纳米粒子的微波吸收性能 总被引:12,自引:0,他引:12
The microwave-absorbing behavior of substituted M-type barium ferrite nano-particles was investigated. The nano-particles were synthesized with coprecipitation-melted salt method. For the purpose of comparison, corre-sponding micro-particles were also prepared through direct coprecipitation and sintering. XRD and TEM of the nano-particles showed that the ferrite was hexagonal in structure and widely distributed in size with particle size being less than 100nm, the complex permittivity and permeability of a 1.50mm thick specimen and a 1.40mm thick specimen containing 60% by weight of substituted M-type barium ferrite nano-particles and micro-particles were measured respectively in X band (8.2~12.4GHz) range, from which the reflection loss (R.L.) of microwaves was calculated and two comparative absorption curves were given. The results showed that the synthetic nano-particles could well absorb microwaves in X band. The absorption was larger than 10dB in the range of 9.2~12.4GHz while the maximum absorption was 38.6dB at 10.6GHz. 相似文献
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刘宗林 《高等学校化学学报》1997,18(4):563-566
用两种改进的方法,由联苯甲酰与3-戊酮反应制得α、β-二甲基脱水丙酮联苯酰(1),其结构由熔点、IR、HNMR确定,从HNMR谱推测:用乙醇作溶剂,加入KOH、联苯甲酰及3-戊酮,于室温搅拌3h后放置3天,所得IA为两对对映体;用苯作溶剂,加入适量聚乙二醇400(PEG400),其它反应物同方法1,加热回流3h,所得产物IA仅为一对对映体,改进的方法都缩短短了反应时间,上述两种方法得到的产物,经脱 相似文献
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