Intriguing ZnO dendritic nanostructures have been synthesized by a two-step chemical vapor deposition process. Regular nanorods grow uniformly to the presynthesized ZnO nanowires on silicon substrate, the secondary nanorods are single-crystal hexagonal ZnO, and each nanorod grows along the [0001] direction. The relationship between the secondary-grown nanorods and the primary ZnO nanowire is not epitaxial due to the high temperature-increasing rate during the rapid grown process. The size and morphology of branches can be controlled by adjusting the temperature and duration of growth. Room temperature photoluminescence (PL) and mircrowave absorption properties of the ZnO dendritic nanostructures have been investigated in detail. The value of minimum reflection loss for the composite with 50 vol % ZnO dendritic nanostructures is -42 dB at 3.6 GHz with a thickness of 5.0 mm. Hierarchical nanostructures of this type are ideal objects for the fabrication of nanoscale functional devices.

Nanofibrous biocomposite scaffolds of poly(vinyl alcohol) (PVA) and graphene oxide (GO) were prepared by using electrospinning method. The microstructure, crystallinity, and morphology of the scaffolds were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The mechanical properties were investigated by tensile testing. Moreover, Mouse Osteoblastic Cells (MC3T3-E1) attachment and proliferation on the nanofibrous scaffolds were investigated by MTT [3-(4,5-dimeth-ylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay, SEM observation and fluorescence staining. XRD and FTIR results verify the presence of GO in the scaffolds. SEM images show the three-dimensional porous fibrous morphology, and the average diameter of the composite fibers decreases with increasing the content of GO. The mechanical properties of the scaffolds are altered by changing the content of GO as well. The tensile strength and elasticity modulus increase when the content of GO is lower than 1 wt %, but decrease when GO is up to 3 and 5 wt %. MC3T3-E1 cells attach and grow on the surfaces of the scaffolds, and the adding of GO do not affect the cells' viability. Also, MC3T3-E1 cells are likely to spread on the PVA/GO composite scaffolds. Above all, these unique features of the PVA/GO nanofibrous scaffolds prepared by electrospinning would open up a wide variety of future applications in bone tissue engineering and drug delivery systems.

Zinc peroxide (ZnO 2 ) hollow spheres of 100-200 nm diameter were synthesized by a simple hydrothermal method by using H 2 O 2 and ZnO powder as reagents without the assistance of any surfactant. O 2 bubbles in situ generated by the decomposition of H 2 O 2 served as a soft template in the formation of ZnO 2 spheres. Zinc oxide (ZnO) hollow spheres were obtained by heat treatment of ZnO 2 hollow spheres at 180 °C for 10 h in air. The products were characterized by XRD, FT-IR, TEM, HRTEM, and FESEM. The transition temperature of ZnO 2 to ZnO was determined to be 229 °C by TG-DTA. Photoluminescence (PL) properties of the products were investigated and the origin of the two peaks at 392 and 448 nm in the PL spectrum of ZnO 2 was discussed. Furthermore, the growth mechanism of the ZnO 2 hollow spheres was discussed in detail.