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In this paper, the nominal formula Mg2(SixAl1-x)O4-δ (x≤0.2) ceramics were synthesized by traditional solid phase reaction methods, and the phase evolution and microstructures of that were investigated by XRD and SEM. The testing results of XRD and SEM show that by substitution of Al for Si in the B site of Mg2SiO4, the MgSiO3 secondary phase can be suppressed, whereas the secondary phase of MgAl2O4 appears gradually with increasing Al-substitution amounts. The relative dielectric constants of Mg2(SixAl1-x)O4-δ(x≤0.2) ceramics increase from 7.0 of Mg2SiO4 to 9.5 of Mg2(Si0.8Al0.2)O4, and the Q×f value is improved significantly and reached the maximum at x=0.1 where the optimum combination of microwave dielectric properties are obtained: er = 8.6, Q×f = 83,000 GHz, τf = -60ppm/°C.

NiZn Ferrite film was deposited on silicon oxide particles by using chemical plating. Samples with different deposition time 0.5h, 1.0h and 2.0h were prepared and analyzed. SEM and XRD were used to characterize the morphology and structure of composite. VSM and impedance analyzer system were used to measure the magnetic property. It was shown that ferrite was successful deposited to silicon oxide particles and the ferrite film was increased with the increase of deposition time. Particles were completely coated by ferrite with 2.0h deposition. Saturation magnetized can reach 27.597emu/g and cut-off frequency can reach 1.5GHz.

ZnO thin films have been deposited on (0001) sapphire substrates using potassium (K) as a dopant by radio frequency magnetron sputtering technique. The electrical properties, crystallinity and surface morphology of as-grown ZnO films are investigated by Hall measurement, X-ray diffraction and Atom Force Microscopy. Results show that the structure and electrical properties of p-K:ZnO films are strongly dependent on the substrate temperature. From 300 to 700°, all K-doped ZnO samples prepared under rich oxygen atmosphere possess p type conductivity, and the best results are obtained at 500° with the hole carrier concentration, resistivity and hole mobility of typical 3.19×1017 cm−3, 10.7 Ω.cm, and 1.83 cm2/V.s, respectively. At the same temperature, the p-K:ZnO films also exhibit the best surface quality with the strongest intensity of (101) diffraction peak, and the preferred orientation (002) peak becomes too weak to be observed. The surface morphology is also smoother and uniform with the average roughness of 105.7 nm and grain size of 231.3 nm.

Quartz crystal microbalance (QCM) modified with graphene has been fabricated using solution drop-coating method and used for the detection of formaldehyde. Measurement was based on frequency shifts due to the adsorption of vapor at the surface of modified electrode. It was found that frequency shifts were linear to the concentrations of analytes in the range of 10 and 100 ppm with the correlation coefficients of above 0.996. The influence of humidity on the sensor was also examined. Results showed that the humidity effects were innegligible.