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Flotation is often employed to separate valuable natural minerals and gangue minerals. However, few studies have been conducted on artificial mineral flotation. Anosovite, the primary mineral in titanium slag, is a typical artificial mineral that can be enriched by flotation. In the present work, flotation behavior and adsorption mechanism of anosovite in salicylhydroxamic acid (SHA) solution were studied. The influence of pH and SHA dosage on anosovite flotability was investigated. Micro-flotation test results show that a pH range of 7–8.5 is available for SHA to collect anosovite. A maximum recovery of 93.26% can be obtained with SHA dosage of only 4×10−5 mol/L. In addition, TOC, zeta potential, FTIR, SEM-EDS, and XPS analyses were used to study the adsorption mechanism. Results demonstrated that SHA adsorption is governed by chemisorption. XPS studies further suggested that chemical adsorption occurred at the Ti sites on the anosovite surface.

Reduced graphene oxide (rGO)/Ni hybrids with different mass ratio are successful synthesized in order to tune the microwave absorption together with the electromagnetic shielding performance. By properly adjusting the permittivity and permeability derived from different contents of the rGO and Ni, an rGO/Ni composite with excellent microwave absorption properties is obtained. An optimal reflection loss value of −39.03 dB at 13 GHz is achieved for the composite with rGO/Ni ratio of 1:1, and the bandwidth less than −10 dB can reach up to 4.3 GHz (from 11 to 15.3 GHz) with a thickness of 2.0 mm. Furthermore, the composite with rGO/Ni ratio of 4:1 shows superior electromagnetic shielding performance as high as 52 dB, which far surpasses the best value for most carbon-based materials. Fundamental mechanisms for absorbing and shielding performance are discussed.

Inspired by the birch bark, which has multilayered structures, we fabricated layer-by-layer (LbL) assembled montmorillonite (MMT) and poly(p-aminostyrene) (PPAS) nanocomposites on cotton fiber curved surfaces to provide protection from atomic oxygen (AO) erosion. The multilayer coated fibers had high flexibility, uniformity, defect free, ease of preparation and low cost. The AO erosion durability has been dramatically enhanced which was evidenced by testing in the ground-based AO effects simulation facility. And the dimension and surface morphologies of the fibers observed by SEM had few changes, indicating excellent AO erosion resistant ability of the coatings. These results provide us a new method to design fibrous materials exposed directly in low earth orbit environment.

Quantum chemical studies for the nine N 1 3 isomers with low spin were carried out at the UHF/6-31G*, UB3LYP/6-31G* and UMP2/6-311G* levels of theory. The most stable N 1 3 isomer is structure 1 with C 2 v symmetry, whichcontains two separated pentazole rings connected by three nitrogen atoms. The results show that structures 1, 2, 3, 4 and 5 which are composed of the pentazole ring are more stable than the open chain structure 6 and structures 8 and 9 which contain the four- and six-membered rings. This suggests that the pentazole ring is a fundamental stable structural unit, which is applicable not only for the even-numbered nitrogen clusters, but also for the large odd-numbered clusters.

The structures and stabilities of eleven N13 + and N13 − isomers have been investigated with second-order Moller–Plesset (MP2) and density functional theory (DFT) methods. Five N13 + isomers and six N13 − isomers are all reasonable local minima on their potential energy hypersurfaces. The most stable N13 + cation is structure C-2 with C2v symmetry, which contains a pentazole ring and two N4 open chains. It is different from those of the N7 + and N9 + clusters, but similar to the N11 + cluster. Meanwhile, the most stable N13 − structure A-2 is composed of a pentazole ring and a six-membered ring connected by two nitrogen atoms. It is not only different from those of the N7 − and N9 − clusters, but also from the N11 − cluster. The decomposition pathways of structures C-2 and A-2 were investigated at the B3LYP/(aug)-cc-pVDZ level. From the barrier heights of the structures C-2 and A-2 decomposition processes, it is suggested that C-2 is difficult to observe experimentally and A-2 may be observed as a short-lived species. Figure Optimized geometrical parameters of N13 + isomer C-2

Recent experiments indicated that disorder effect in DNA may lead to a transition of the charge transport mechanism from band resonant tunnelling to thermal activated hopping. In this letter, based on Mott's variable-range hopping theory we present a kinetic study for the charge transport properties of DNA molecules. Beyond the conventional argument in large-scale systems, our numerical study for finite-size DNA molecules reveals a number of unique features for (i) the I-V characteristics, (ii) the temperature and length dependence, and (iii) the transition from conducting to insulating behaviors.