Optimization of preparation parameters and characterization of the Mn0.5Zn0.5Fe2O4 thermal-sensitive magnetic ferrofluid prepared by the hydro-thermal method
The bare magnetic Mn<inf>0.5</inf>Zn<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> nanoparticles were prepared by the hydro-thermal method. The optimized preparation conditions were obtained by the orthogonal experiment. Crystal structure and the grain diameter of the particles were observed by X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM), and the Curie temperature of the bare particles and the performance of the magnetic moment of the particles at different temperatures were characterized by the Vibrating Sample Magnetometer (VSM). The bare particles were modified by the oleic acid, and the modification effect was verified by the Infrared Test (IR). Mn<inf>0.5</inf>Zn<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> thermal-sensitive magnetic ferrofluid with excellent performance were prepared by dissolving the modified particles in the kerosene carrier. The saturation magnetization could reach up to 278Gs and the Curie temperature is confirmed to be 322K, which indicates that the quality of the Mn<inf>0.5</inf>Zn<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> thermal-sensitive ferrofluid is better than other Mn<inf>0.5</inf>Zn<inf>0.5</inf>Fe<inf>2</inf>O<inf>4</inf> thermal-sensitive ferrofluids prepared by the coprecipitation method previously reported (Saturation magnetization: 150Gs, Curie temperature: 340K[1]).
Hydrothermal preparation of ultrafine ferrites and their sintering
Preparation de poudres ultrafines et quasispheriques de ferrites NiFe 2 O 4 , ZnFe 2 O 4 , Ni x Zn 1−x Fe 2 O 4 , Mn 0,5 Zn 0,5 Fe 2 O 4 et CoFe 2 O 4 dans des conditions hydrothermales moderees par precipitation de nitrates metalliques avec de l'ammoniaque. Ces poudres sont frittees a 1000°C sans additif avec obtention d'une densite proche de la densite theorique
Kinemamtic analysis of flying-saw vehicle
The paper analyzes the kinematic motion of the flying-saw vehicle.After the analysis,it is concluded that the ac- celerating periods and decelerating periods in both forward and backward directions will follow sin~2αcurve and,in order to increase the sawing dimensional accuracy,flying-saw vehicle must come back as soon as possible while acceleration remains constant.Based on this premise,the paper gives out the equations of kinematic motion of the flying-saw vehicle in every sta- ges and one example result in a common situation.By now this method has been used in the real situation.