A continuous metal-insulator transition driven by spin correlations

While Mott insulators induced by Coulomb interactions are a well-recognized class of metal-insulator transitions, insulators purely driven by spin correlations are much less common, as the reduced energy scale often invites competition from other degrees of freedom. Here, we demonstrate a clean example of a spin-correlation-driven metal-insulator transition in the all-in-all-out pyrochlore antiferromagnet Cd2Os2O7, where the lattice symmetry is preserved by the antiferromagnetism. After the antisymmetric linear magnetoresistance from conductive, ferromagnetic domain walls is removed experimentally, the bulk Hall coefficient reveals four Fermi surfaces of both electron and hole types, sequentially departing the Fermi level with decreasing temperature below the Néel temperature, TN = 227 K. In Cd2Os2O7, the charge gap of a continuous metal-insulator transition opens only at T ~ 10 K << TN. The insulating mechanism parallels the Slater picture, but without a folded Brillouin zone, and contrasts sharply with Mott insulators and spin density waves, where the electronic gap opens above and at TN, respectively.

Optimal ratio of spans of continuous bridges

The article deals with the creation of continuous metal and monolithic reinforced concrete bridge spans, which are the most effective. Efficiency is achieved by finding opportunities for the unification of structures with the most successful options for providing them with the required load-bearing capacity with the lowest cost of building materials. The bending moments that occur in the sections of a continuous structure are distributed more evenly and take on smaller values in the span than in a split structure. However, the efficiency of continuous structures can be further improved by introducing a certain coefficient of the length of the extreme spans of the bridge relative to the average ones. This allows you to achieve equality of the reference or span bending moments. As a result, the design will work in such a way that it will be possible to build the bridge span as if from three types of unified blocks, which will reduce the complexity and cost of construction work. As an example, in this case, the ratio of spans and the corresponding division into blocks for four-span continuous bridges are determined.

Advanced necklace-like metal organic framework with ultrahighly continuous structure in membrane for superior butanol/water separation

The fabrication of mixed matrix membranes (MMMs) for pervaporation recovery of butanol from aqueous solutions is garnering significant attention. However, constructing highly continuous metal-organic framework (MOF) with reasonable loading as...

Unification in the design of four-span continuous bridges

The article deals with the creation of continuous metal and monolithic reinforced concrete bridge span structures, which are the most efficient. Efficiency is achieved by searching for opportunities to unify structures with the most successful options for providing them with the required load-bearing capacity with the lowest cost of building materials. If a certain coefficient of the length of the extreme relative to the average is introduced, there can be achieved the equality of the transverse moments of spans. Such performance of the structure will allow building the bridge span as if combined from three types of unified blocks, which would reduce the labor complexity and the cost of construction work.