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61.
首先用sol-gel法制得了Pb0.95Sr0.05(Zr0.52Ti0.48)O3纳米粉料(简称PZT),然后采用固相反应法制备了ζ(PZT:NiCuZn)为1:9和3:7的两种复合材料。研究Ni0.26-xCu0.19+xZn0.55Fe2O4铁氧体的组成对低温烧结复合材料的显微结构、电磁性能的影响。结果表明:当x=0.02的化学组成为主配方时,复合材料可实现900℃低温烧结,且ζ(PZT:NiCuZn)为1:9的复合材料的μi高达92,Q值为39,ε′为19;而ζ(PZT:NiCuZn)为3:7的复合材料的μi为26,Q值为19,ε′为32。 相似文献
62.
随着通信技术的发展,对无限通信设备的集成度有了更高的要求,天线小型化成为目前重要的研究方向。等磁介电材料是一种既具有磁导率又具有介电常数,且磁导率和介电常数几乎相等的材料,使用等磁介电材料作为天线的基板,能有效的减小天线的尺寸,提高带宽,增加辐射效率。铁氧体是由Fe2O3和一种或多种金属氧化物复合而成,具有较高的磁导率和介电常数,由于其同时具有磁特性和介电特性,是一种潜在的等磁介电材料。综述了近几年尖晶石结构磁介电材料的国内外研究进展,着重讨论了掺杂改性对烧结温度、磁导率、介电常数、直流电阻等电磁特性的影响。最后指出目前研究中存在的问题,并展望了该材料在未来发展的方向。 相似文献
63.
Gang Wang Dainan Zhang Fang Xu Xin Huang Yan Yang Gongwen Gan Yuanming Lai Yiheng Rao Cheng Liu Jie Li Lichuan Jin Huaiwu Zhang 《Ceramics International》2019,45(8):10170-10175
Structural characteristics exert significant influences on microwave dielectric properties, and ion substitution is widely adopted to modify material performances by adjusting the crystal structure. In this work, low loss Li3Mg2-xCuxNbO6 (x?=?0–0.04) ceramics were prepared by Cu2+ substitution. The impacts of Cu2+ substitution for Mg2+ sites on the microwave dielectric characteristics and crystal structure were discussed in detail. Rietveld refinement results implied that a single Li3Mg2NbO6 phase was formed. Additionally, a dense and homogeneous microstructure with grain sizes of 7–9?μm could be achieved, and moderate Cu2+ substitution could significantly promote the grain growth. The correlation between microwave dielectric characteristics and crystal structure was discussed by calculating some structural parameters. The εr was determined by the polarizability. The Q?×?f was influenced by the packing fraction. The τf value was dependent on the NbO6 octahedron distortion, and the τf value could be adjusted to near zero for x?=?0.02. Typically, the Li3Mg2-xCuxNbO6 (x?=?0.02) composition exhibited remarkable microwave dielectric performances: εr?=?15.75, Q?×?f?=?92,134?GHz (9.86?GHz) and τf?=??2?ppm/°C, making it a promising candidate for temperature-stable millimeter-wave applications. 相似文献
64.
65.
陆怀武 《常州信息职业技术学院学报》2002,1(2):59-61
通过对澳大利亚方言的俚语、词汇、语法与伦敦英语进行比较,发现其构成的特点,并对澳大利亚英语进行大致的了解,从而进一步认识澳大利亚的语言文化。 相似文献
66.
Yan Yang Huaiwu Zhang Jie Li Fang Xu Gongwen Gan Dandan Wen 《Ceramics International》2018,44(9):10545-10550
NiCuZn ferrite with superior magnetic performance is vital ceramic material in multilayer chip inductors (MLCI) applications. In this study, low-temperature-sintered Ni0.22Cu0.2Zn0.58Fe2O4 ferrite ceramic doped with 1.0?wt% Bi2O3-x?wt% Nb2O5 (where x?=?0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) was synthesized via solid-state reaction method. Effects of Bi2O3-Nb2O5 additives on microstructures and magnetic properties of NiCuZn ferrite ceramics sintered at 900?°C were systematically investigated. Results indicate that an appropriate amount of Bi2O3-Nb2O5 composite additives can significantly promote grain growth and densification of NiCuZn ferrite ceramics when sintered at low temperatures. Specifically, samples doped with 1.0?wt% Bi2O3 and 0.4?wt% Nb2O5 additives exhibited excellent initial permeability (~ 410 @ 1?MHz), high cutoff frequency (~ 10?MHz), high saturation magnetization (~ 54.92?emu/g), and low coercive force (~ 20.32?Oe). These observations indicate that NiCuZn ferrite ceramics doped with appropriate amounts of Bi2O3-Nb2O5 additives are great candidate materials for MLCI applications. 相似文献
67.
Fang Xu Dainan Zhang Yulong Liao Gang Wang Xiaolei Shi Huaiwu Zhang Quanjun Xiang 《Journal of the American Ceramic Society》2020,103(2):849-858
Plasma processing technology, as a promising method to enhance photocatalytic activity of catalyst, is gradually attracting extensive interest from researchers. However, the main mechanism of plasma-treated photocatalyst on hydrogen production is not clear. In this work, 2D Ti3C2Tx MXene is selected as a co-catalyst of graphitic carbon nitride (g-C3N4), which carries out a plasma treatment (500°C) under N2/H2 atmosphere. Due to plasma treatment, there is a higher proportion Ti–O functional groups on surface of layered Ti3C2Tx MXene, especially for Ti4+. The obtained g-C3N4/p-Ti3C2Tx photocatalyst with sandwich-like structure shows an enhanced photocatalytic activity. The rate of hydrogen generation of CN/pTC3.0 sample without Pt co-catalyst is 25.4 and 2.4 times that of pure g-C3N4 and CN/TC3.0 samples, respectively. The improved photocatalytic activity is attributed to presence of Ti4+ due to plasma treatment, which can capture photo-induced electron from g-C3N4 and improve the separation of electrons and holes after visible light irradiation. The cyclic hydrogen production of the photocatalyst demonstrates good photocatalytic stability. In addition, this method of plasma treatment under N2/H2 atmosphere is feasible to develop a high-performance co-catalyst, which can be extended to other photocatalysts with two-dimensional structure for photocatalytic water-splitting applications. 相似文献
68.
基于Herzer理论,对Co基薄带材料的纳米晶化及软磁性能改善进行了大量实验研究,解决了晶化中薄带变脆和内层绝缘磁耦合问题,成功地研制出用于射频域的抗EMI无源滤波器。测试结果表明其有着优良的抗噪性能。 相似文献
69.
Rui Peng Yongcheng Lu Yuanxun Li Hua Su Liang Shi Guoliang Yu Yuanming Lai Qiang Zhao Xiaolei Shi Huaiwu Zhang 《Journal of the American Ceramic Society》2021,104(9):4614-4623
The influence of manganese substitution on the sintering and dielectric properties of Mg3B2O6 (MBO) was studied, and the detailed mechanism of variation was discussed using density functional theory calculations. The characterization method involved a network analyser, differential–thermal analyses, thermomechanical analyses, X-ray diffraction, and scanning electron microscopy. Manganese substitution formed a two-phase system (MBO and Mg2B2O5), improved the dielectric property, densified the microstructure, lowered the activation energy, decreased the crystallite size, modified the band structure property, and strengthened the covalency of MgO6 octahedron. The 7% mole substitution of manganese to magnesium improved the dielectric properties of MBO to 7.06 for εr and 61 100 GHz at 15 GHz for Q × f, −54.8 ppm/°C for τf. The intrinsic densification temperature decreased from 1350 to 1175°C with 97.7% relative density. 相似文献
70.