Pure and neodymium-doped gadolinium calcium oxoborate crystals of high quality were grown by the Czochralski method. The orientation of crystal was precisely determined, and the samples for measurements were prepared. Through synchrotron x-ray topography and high-resolution x-ray diffractometry, the twin structure was discovered. Some properties such as the figure of merit value, and dielectric, piezoelectric, and elastic constants were measured along with a discussion of the anisotropy of the laser properties.

A new approach to the synthesis of a novel silicon-containing polyester by noncarbothermal method directly from SiO2 was studied. At first, a high reactive pentacoordinate organic silicon compound (KSi(OCH2CH2O)2(OCH2CH2OH)) was prepared by the reaction of the fumed silica with ethylene glycol (EG) and KOH. Then, a novel double hydroxy tetracoordinate silicon monomer (OCH2CH2O)Si(OCH2CH2OH)(OCH2CH2OCH2CH2OH) was synthesized by the reaction of ClCH2CH2OH with reactive pentacoordinate silicon compound. Finally, a silicon-containing polyester was synthesized by low temperature solution condensation between tetracoordinate silicon compound and p-phthaloyl chloride in dimethyl sulfoxide (DMSO). The product was characterized by FTIR, TG, GPC, etc. The IR spectra of polyester exhibited a characteristic strong absorption band for ester carbonyl in the 1722.2cm-1. IR spectra also showed absorption at 1124.6cm-1 due to the O-Si-O group. TG analysis showed its good thermal stability. GPC analysis showed that the number average molecular weight of this siliconcontaining polyester was about ninety thousand.

The major inorganic component of the rice husk (RH) is silica (∼20%)[1]. In the past, the utilization of RH mainly concentrated on the ash of the rice husk, such as using rice husk ash (RHA) as filler in plastics, especially in polypropylene (PP). In this work, RH was directly used as filler in PP. Some treatments were applied to the RH. PP composites of different filler loadings were compounded using a laboratory size two-roll mixer at a temperature of 180° C for a period of 5 minutes. The tensile strength of the RH-PP composites increased steadily with increasing filler loading until about 20% loading. The impact strength of the composites decreased with the increasing filler loading. Torques and melt index (MI) of composites with various filler loadings were investigated. The MI of the composite decreased with the increasing filler loading. RH showed more potential than RHA as PP filler.