Due to the existence of vacancy-sized free volumes in the interfacial structure of $\alpha \text{-}\mathrm{Fe}∕{\mathrm{Nd}}_2{\mathrm{Fe}}_{14}\mathrm{B}$ nanocomposite magnets, their energy product is thought to be enhanced by interfacial modification. To improve the interfacial structure, in the present study, we produce an interfacial amorphous phase with a volume fraction of 14%–16% in $\alpha \text{-}\mathrm{Fe}∕{\mathrm{Nd}}_2{\mathrm{Fe}}_{14}\mathrm{B}$ nanocomposites by a proper addition of Nb in the melt-spun NdPrFeCoB. The nanocomposites show a higher maximum energy product ${\left(BH\right)}_{\max }=23.2\mathrm{MG}\mathrm{Oe}$ and a higher remanence $M_r=0.78M_s$ compared with the one without interfacial modification, ${\left(BH\right)}_{\max }=16.1\mathrm{MG}\mathrm{Oe}$ and $M_r=0.75M_s$ .

A method for assessing the stability of slurry-supported trenches considering anisotropy and nonhomogeneity using the upper-bound theorem of limit analysis is presented. Only anisotropy and the nonhomogeneity of the cohesion were taken into account in this study. The influence of anisotropy and nonhomogeneity on trench stability was investigated via parametric studies. A series of stability charts was obtained for slurry-supported trenches. It is shown that the results obtained from the upper-bound solutions agree well with those obtained through the variational limit-equilibrium closed-form solutions in isotropic and homogeneous trenches. This article first describes the influences of anisotropy and nonhomogeneity on the required unit weight of slurry, and then the procedures for getting the factor of safety are presented. In addition, the influence of anisotropy and nonhomogeneity on the shape of the trench critical failure surface and on the location of the slip surface of the sliding mass is decribed. The article also gives examples to illustrate the variation in the safety factor with trench depth under different anisotropy and nonhomogeneity conditions.

The mechanical behavior of the interfaces between fine sea sand and offshore structure is regarded as a quite important issue that influences the foundation-bearing capacity and structural safety. In this work, by employing a modified shear apparatus with a ring-transparent sample container, a series of interface shear tests were conducted to shed light on the effects of the applied normal stress, initial relative density, and the roughness of the steel surface. Based on image analysis, the horizontal deformation at various vertical positions within the sand specimen was captured. In addition, the postshearing particle-size distributions of sand specimens were measured and compared. From the acquired test results, it was demonstrated that for the dense and medium dense sand–steel interfaces, strain softening is a typical shear behavior, regardless of the roughness of the steel surface. The mobilized shear stress of the interface with a smooth steel surface reaches the peak strength earlier than that of the rough one and then rapidly declines to residual strength within a short softening stage. The shearing zone in sand specimens can be divided into a large deformation zone and a small deformation zone. The shear deformation that occurs within the sand specimens sheared against the smooth steel surface is negligible and concentrated very close to the interface. However, for rough surface and dense sand, the interlocking between sand and steel forces the deformation of sand specimens to arise in greater scope and magnitude, accompanied by significant particle crushing.