No abstract

The nanosized mixture powders of ferric oxide and nickel oxide prepared by the coprecipitation in a stoichiometric ratio to form NiFe 2 O 4 were subjected to shock wave treatment. The nanosized nickel ferrites with different particle sizes were synthesized by means of varying initial packing density of the mixture. Compared with nickel ferrite prepared by conventional calcination, the magnetization of ones by shock wave treatment increases significantly. It is believed that shock wave treatment is a novel method for the preparation of nanosized powders of composite metal oxides with particular physical properties.

Clinoenstatite (MgSiO 3 ) powders were synthesized by precipitation process using magnesium nitrate (Mg(NO 3 ) 2 . 6H 2 O) and sodium silicate (Na 2 SiO 3 . 9H 2 O), and clinoenstatite ceramics were prepared by sintering its powder compacts at 14001C for 3 and 5 h. The shrinkage (4.53%), bending strength (31.78 MPa), relative density (82.84%), and Young's modulus (8.51 GPa) were investigated. The percentages of weight loss of the clinoenstatite ceramics were listed as 1.2970.55%, 1.3670.30%, 7.3171.54%, and 10.7770.93% after 1-, 3-, 7-, and 14-day soaking in the Tris-HCl solution. The biocompatibility studies showed that clinoenstatite ceramics could not induce the formation of HAp in simulated body fluid, but the ionic products of the clinoenstatite powder extracts promoted the proliferation of the mouse fibroblasts (L929 cell). The murine embryonic mesenchymal stem cells adhered well and proliferated more on the clinoenstatite ceramics than on the traditional hydroxyapatite ceramics. These results showed that clinoenstatite bioceramics possessed good cell biocompatibility and might be used for preparation of bone implants or biocoatings.

The thermal conductivities of ethylene glycol monobutyl ether, dimethyl ether, methyl ethyl ketone, castor oil, and vegetable seed oil in the near-saturated liquid phase have been measured in the temperature range from (229 to 375) K by the transient hot-wire method with a bare platinum wire. The uncertainty of the experimental results was estimated to be within ±2.0%, and the reproducibility of the data was better than ±0.5%. The liquid thermal conductivities obtained have been correlated as a polynomial function of the temperature, with an absolute mean deviation from the experimental data of less than 0.4% and a maximum deviation of less than 0.6%.