[en] In ferromagnet/antiferromagnet bilayers and core/shell nanoparticles, an exchange-bias-like loop bias phenomenon in the ferromagnet is observed solely due to the long-range dipolar interactions between ferromagnet and antiferromagnet. With increasing cooling field, the loop bias field may increase from zero in the bilayers or from a negative value in the core/shell nanoparticles to a positive saturated value, depending on the interfacial dipolar interaction and/or ferromagnetic/antiferromagnetic thickness. Using a modified Monte-Carlo method and the Meiklejohn–Bean model, the interfacial dipole fields (up to several teslas) and the domain sizes imprinted on the interfacial antiferromagnet are explicitly calculated to elucidate the cooling field dependence of loop bias, which is governed by distinct mechanisms at the flat and curved interfaces. Finally, through simply discussing the roles of lattice structure, ferromagnetic dipolar interaction, and simulation time, it is evidenced that the dipole-induced loop bias is ubiquitous and applicable for stabilizing a ferromagnet, irrespective of the interface mismatch and the undeterministic diffusion between different ingredients. This work helps us to develop the spintronic devices with nonatomic-contact nanostructure assemblies. (paper)

[en] The structure-property of a Ni-based superalloy fabricated by selective laser melting (SLM) was investigated under very high cycle fatigue (VHCF), and the subsurface cracking with fisheye pattern becomes a remarkable failure mode. Due to the presence of subsurface failure, the descending S–N curve property is represented. Based on 2D & 3D microscopic observation, a rough region with facets and inclusions, named as “multi-inclusion assisted facetted cracking zone (MAFCZ)”, is present within the fisheye. By combining electron backscatter diffraction analysis, the subsurface failure is related to grain size & orientation, microtexture and crystal defects. The crack is nucleated from the large grain slip with the highest Schmid factor under the assistance of the inclusions. The rough surface morphology with crack deflection reveals ultra-slow crack growth behavior within MAFCZ. Combined with failure modeling and fracture mechanics analysis, the subsurface failure mechanisms of SLM Ni-based superalloy under the VHCF are elucidated.

[en] The magnetocaloric effect in an array of anisotropic zinc ferrite nanoparticles was studied based on Monte Carlo simulations. For the 5-nm-diameter zinc ferrite nanoparticles, the maximum magnetic entropy change of ∼1.2 J kg⁻¹ K⁻¹ for the anisotropy with monodispersed orientation and small magnitude was obtained, roughly twofold larger than that in the dispersed anisotropic counterparts in the experiments, and the maximum adiabatic temperature variation of ∼2.25 K at 115 K was predicted, conveying that the zinc ferrite nanoparticles with proper anisotropy magnitudes and monodispersed easy axes are prospective portable, environmental friendly and rotary magnetic refrigerants with high magnetocaloric energy converting efficiencies and short operation times.

[en] Highlights: • Effects of nitrogen on nutrient removal and biodiesel production of mono- and mix-cultured microalgae was investigated. • Microalgae co-culture could remove 70.4%–74.1% nitrogen. • Algae grown in media with different nitrogen sources had better growth performances. • The ultimate biomass increase and productivity in the mix-culture were the highest. • The biodiesel yields in this study ranged from 8.5–11.2 g-biodiesel/100 g-dry weight. -- Abstract: Effects of nitrogen source inhomogeneity on nutrient removal and biodiesel production of mono- and mix-cultured microalgae were investigated in this study. The microalgal growth characteristics, lipid accumulation, biodiesel production and nutrient removal were determined by mono- or co-culturing microalgae Chlorella vulgaris and Scenedesmus dimorphus in media with different nitrogen sources. The results showed that microalgae cultivated in media with different nitrogen sources indicated higher nitrogen removal, biomass increase and productivities of biomass, lipids and biodiesel than media with the sole nitrogen source. As for the microalgae grown in media with the same nitrogen source, the pattern for the lipid content was in the relationship C. vulgaris > mixed culture > S. dimorphus. The fatty acids of microalgae mainly consisted of C16:0, C16:1, C18:0, C18:2 and C18:3, accounting for 79.6–90.6% of the total. The biodiesel production in this study ranged from 8.5 to 11.2 g-biodiesel/100 g-dry weight. This study presents one of the few studies, suggesting that nitrogen source itself can influence the nutrient removal and biodiesel production of mono- and mix-cultured microalgae.