Preparation, characterization and coagulation behaviour of polyferric magnesium silicate (PFMSi) coagulant.

A composite coagulant polyferric magnesium silicate (PFMSi) was synthesized by co-polymerization. The structure and morphology of PFMSi were characterized by X-ray diffraction, Fourier transform infrared spectra and scanning electron microscope microphotographs; meanwhile, the coagulation efficiency was evaluated under different ratios of Fe/Si, Mg/Si, basicity ([OH]/[M] ratio), and dosage. The results suggested that the PFMSi coagulant shows an amorphous phase structure, and new chemical compounds had been formed; simultaneously, the different preparation conditions had major effects on coagulation performance. Additionally, the raw water collected from Pearl River was used as a treated water sample to verify the coagulation efficiency of PFMSi. Overall, it is suggested that PFMSi is an efficient coagulant in the removal of turbidity, UV254 and total organic carbon, and it shows a markedly better coagulation performance than polymeric aluminium and non-modified coagulant. The study of coagulation kinetics and zeta potential showed that adsorption-bridging was the main mechanism for the introduction of silicon.

[Simulation of SAR and temperature distribution for tumor RF thermotherapy with double-frequencies and double-plates].

The model establishment and numerical simulation of specific absorption rate (SAR) and the unsteady-state temperature distribution for radio frequency (RF) thermotherapy with double-frequencies and double-plates are presented in this paper. The model can correctly reflect the attenuation of electromagnetic wave in the biotissue. The variation of perfusion with temperature and the lower perfusion in tumor tissue are fully considered in the simulation of unsteady-state temperature profiles. Also presented are detailed analyses and discussions on the characteristics of SAR and temperature profiles, and the effects of the plates location and power as well as of the perfusion on the depth of effective treatment.

[Study of a new microwave applicator for hyperthermia treatment of uterocervical cancer].

A new microwave applicator for intracavitary hyperthermia treatment of uterocervical cancer has been designed and tested. Compared with the traditional microwave applicators, the exposed inner conductor of this applicator is replaced by a cone-helical antenna with the reflect shade. We confirm that the heat pattern of the applicator is shifted towards the tip in muscle tissue equivalent phantom material. The result indicates that this new applicator may play an important role in clinical use for treatment.