Shell-core structures of Fe(C), Co(C) and Fe-Co(C) nanocapsules, prepared by an arc discharge process in a mixture of methane and helium, have been demonstrated by means of high-resolution transmission electron microscopy (HRTEM). These nanoscale magnetic cores are protected by graphite shells. It has been found that the zero-field-cooled (ZFC) magnetization of Fe-Co(C) nanocapsules that display different characteristics in three temperature ranges can be well interpreted in terms of the unblocking of magnetization of small single-domain particles and the depinning of large multidomain particles. The saturation magnetization of these nanocapsules decreases monotonically, while the coercivity decreases significantly with increasing temperature.

Effects of oxytetracycline (OTC) on soil enzyme activity and structural diversity of soil microbial communities were investigated. The low and moderate OTC inputs of less than 15 mg/kg enhanced microbial growth and increased the total and bacterial and fungal biomasses in the receiving soils. The antibiotic toxicity of OTC although targeted the bacteria in the soils proportionally resulted in greater harmed against the soil fungi than the bacteria and the Gramnegative bacteria fared significantly better than the Gram-positive bacteria. Collectively, the high OTC inputs lowered of soil enzymatic activities and the low and moderate OTC inputs did not have any adverse impact on the soil enzyme activities.

Exchange bias (EB) and magnetic properties of ferrimagnetic (FI) Fe3O4 and antiferromagnetic (AFM) Cr2O3 nanocomposites prepared by mechanical alloying have been investigated. A large EB field of 2.2 kOe at 10 K is observed in one of the nanocomposites, which may be related to the uncompensated and pinned AFM spins at the interface between FI and AFM phases of the nanocomposites. The EB field varies with the strength of cooling field and the content of the Cr2O3 phase, the phenomena observed are explained in terms of interfacial exchange interaction between the two phases.

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We have systematically investigated the structural, magnetic and transport properties of as-quenched and annealed Co20 Nix Cu80-x (0 x 20) granular alloys prepared by melt spinning. The microstructure of granular ribbons of Co-Ni-Cu shows a matrix in which nanoparticles of Co-Ni are well distributed, very different from that of granular ribbons of Co-Cu in which full-grown Co microparticles are embedded in a Cu matrix. The phase segregation in the Co-Ni-Cu granular ribbons is not a pure nucleation and growth process as in the Co-Cu granular ribbons, but also not purely due to spinodal decomposition. In contrast to the ribbons with high Ni content, the low-Ni-content ribbons show an increase in magnetoresistance ( R /R 6.2% at 300 K for Co20 Ni5 Cu75 , which is larger than in as-quenched and annealed Co-Cu ribbons.