A compound bioflocculant CBF-F26, produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its physicochemical and flocculating properties. It was identified as a polysaccharide bioflocculant composed of rhamnose, mannose, glucose, and galactose, respectively, in a 1.3: 2.1: 10.0: 1.0 molar ratio. The average molecular weight was determined as 4.79 9 10 5 Da by gel-permeation chromatography. Infrared spectrum and X-ray photoelectron spectroscopy revealed the presence of carboxyl, hydroxyl and amino groups in its structure. Thermostability test suggested that CBF-F26 was thermostable and high flocculating activity was maintained. Thermogravimetric property, intrinsic viscosity and surface morphology of CBF-F26 were also studied. CBF-F26 was effective under neutral and weak alkaline conditions (pH 7.0-9.0), and flocculating activities of higher than 90% were obtained in the concentration range of 8-24 mg l -1 at pH 8.0. The flocculation could be stimulated by cations Ca 2? , Zn 2? , Fe 2? , Al 3? , and Fe 3? . In addition, the probable flocculation mechanisms were proposed.

Multiwalled carbon nanotubes (MWCNTs) were used to convert radome materials to microwave absorbing materials. Dense MWCNT-fused silica composites were prepared by hot-pressing technique. The composites exhibit high complex permittivities at X-band frequencies, depending on the content of MWCNTs. The value of the loss tangent increases three orders over pure fused silica only by incorporating 2.5vol% MWCNTs into the composites. The average magnitude of microwave transmission reaches −33dB at 11–12GHz in the 10vol% MWCNT-fused silica composites, which indicates the composites have excellent microwave attenuation properties. The attenuation properties mainly originate from the electric loss of MWCNTs by the motion of conducting electrons.

A novel method is reported for the manufacture of transparent polycrystalline alumina ceramics by means of orientating the optical axes of grains parallel to each other. Such ceramics were achieved simply by exposing the slip casting process to a strong magnetic field followed by the traditional processing for translucent alumina ceramics. X‐ray diffraction and orthogonal polarizing microscopy showed that the grains have been successfully orientated in the alumina ceramics. The in‐line optical transmission is much higher than that of the randomly orientated polycrystalline alumina because the optical axes of grains are parallel to each other.