Bonded thin cylinder magnets using Sm-Fe-N anisotropic powder
Anisotropic bonded Sm-Fe-N thin cylinder magnets have been developed by an injection-molding technology using unsaturated polyester resin, because thin and high-performance magnets are needed in order to downsize the motor. A special point for forming was a control of the rate of shrinkage. A multioriented cylinder magnet of 0.8 mm thickness was made by an insertion forming an aluminum column of 18.4 mm diameter and 18 mm height. A radial-oriented cylinder magnet of 15 mm outer diameter, 16 mm height, and 0.5 mm thickness was also made.
Sm/sub 2/Fe/sub 17/N/sub 3/ magnet powder made by using reduction and diffusion method
High performance Sm/sub 2/Fe/sub 17/N/sub 3/ magnet powder is developed by a reduction and diffusion method. Typical remanence, coercivity and maximum energy product obtained are 1.40 T, 1.13 T and 323 kJ/m/sup 3/, respectively. Decreasing samarium content, oxygen content and the amount of /spl alpha/-Fe are found to be the important factors to realize high energy product.
Applications of nanocomposite hydrogels for biomedical engineering and environmental protection
Nanocomposite hydrogels are polymeric networks that possess a unique property of hydration. The presence of alcohols, carboxylic acids and amides as hydrophilic moieties in structure of nanocomposite hydrogels enhances their stiffness and water-absorbing capacity. Addition of cross-linker in the synthesis of hydrogels increases their stability under extreme conditions of temperature, pH and pressure. Natural polymer-based nanocomposite hydrogels are biodegradable, highly hydrophilic and possess good mechanical strength. Gelatin, chitin, cellulose, pectin, carrageenan, starch and alginate are natural polymers commonly used to fabricate nanocomposite hydrogels. Nanocomposite hydrogels have special characteristics such as high swelling rate, selectivity and stimuli-sensitive nature. Here we review nanocomposite hydrogels for environmental protection and biomedical engineering. Applications in biomedical engineering include drug delivery agents, wound dressing, tissue engineering and antibacterials. Applications in environmental protection include ion exchangers, adsorption, photocatalysis and soil conditioning. Many nanocomposite hydrogels show excellent adsorption selectivity for heavy metal ions: Cu2+ up to 30.35 mg/g, Pb2+ up to 35.94 mg/g, and Zn2+ and Fe3+ up to 94.34 mg/g. Xanthan gum-based nanocomposite hydrogel has removed 96% dye from industrial effluent as reported. In addition, most of the nanocomposite hydrogels showed better adsorption capacity for pollutants in the pH range from 5 to 7. The nanocomposite hydrogels could also be regenerated and successfully utilized for several times. Nanocomposite hydrogels are therefore good bio-absorbent materials for environmental detoxification.