0.7BaO·0.3SrO·0.3Nb2O5·0.7TiO2 (SBN/BST) composite ceramics werefabricated using a Powder-Sol (P-S) method with Nb2O5fine powder suspended in the barium strontium titanate (abbreviated as BST) solsolution. By X-ray diffraction (XRD) investigations, it is found that thetetragonal tungsten bronze (TTB) phase and perovskite phase were co-present incompositions. The average grain size of BST and SBN phase is 140 nm and 2.2 μm,respectively. The room temperature relative dielectric constant is 1445 forthis sample measured at 1 kHz and zero bias. In the room temperature, thepyroelectric coefficient of the 0.7BaO·0.3SrO·0.3Nb2O5·0.7TiO2is 39 nc/cm2·°C. The maximum value of FDis about 2.4×10-5 Pa-1/2at 45°C.

SiO2 optical fiber preform, the parent material in manufacturing optical fiber, plays an important role in the properties of optical fiber. In this paper, SiO2 dry gel was prepared by Sol-Gel method. According to this method, the gel was formed by hydrolyzing tetraethyl orthosilicate(TEOS) with hydrochloric acid and ammonia water, and the SiO2 dry gel was obtained by heat treatment of the gel at different temperature. The structure of the dry gel as prepared was characterized by X-ray Diffraction(XRD), Fourier Transform Infrared Spectroscopy(FT-IR) and Scanning electron microscope(SEM). As a result, amorphous structure is proved. Meanwhile, microscopic cracks are found to be decreased by adding formamide and increased when the heat-treatment temperature is above 75°C.