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Enormous p–n heterojunction interfaces and the synergistic effect of In2O3 and rGO species effectively decreased the working temperature for NO detection.

The bilayer SnP3 is recently predicted to exfoliate from its bulk phase, and motivated by the transition of the metal-to-semiconductor when bulk SnP3 is converted to the bilayer, the thermoelectric performance of bilayer SnP3 is studied in our work.

Powders consisting of Si-based nanostructures were synthesized by the extraction of Ca atoms from CaSi2 powders using an inositol hexakisphosphate (IP6) aqueous solution. The raw CaSi2 powders were simply immersed in a diluted IP6 solution, then dried. It is noted that the Si-based nanostructures were easily exfoliated from the powders to expose the surfaces corresponding to the Si {111} planes of the nanostructures. In addition, the Si-based nanostructures were also synthesized by metal atom extraction from SrSi2, BaSi2 and Mg2Si using the IP6 aqueous solution. It was found that the nanostructures mainly including the amorphous Si-oxide phase were obtained for the IP6-treated SrSi2, BaSi2 and Mg2Si powders. Moreover, the amorphous Si oxide-based nanostructures were synthesized from CaSi2 using citric acid, malic acid, FeCl3 and FeCl2 aqueous solutions. It was demonstrated that the morphological and structural properties of the synthesized Si-based nanostructures depend on the silicide templates and the solutions.

A novel strategy was employed to introduce a carbon layer on Si particle to overcome the intrinsic poor electrical conductivity and significant volume change. The carbon layer was fabricated by forming polyphosphazene coating through a facile precipitation polymerization method, followed by carbonization. As a result of formation of core-shell structure, the Si anode exhibited improved cycling stability (740 mA h/g remained after 100 cycles) and rate capability (300 mA h/g at a rate 2C). In addition, 99% coulombic efficiency was remained after 100 cycles.

This paper presents a personalized course recommended algorithm based on the hybrid recommendation. The recommendation algorithm uses the improved NewApriori algorithm to implements the association rule recommendation, and the user-based collaborative filtering algorithm is the main part of the algorithm. The hybrid algorithm adds the weight to the recommendation result of the user-based collaborative filtering and association rule recommendation, implementing a hybrid recommendation algorithm based on both of them. It has solved the problem of data sparsity and cold-start partially and provides a academic reference for the design of high performance elective system. The experiment uses the student scores data of a college as the test set and analyzes results and recommended quality of personalized elective course. According to the results of the experimental results, the quality of the improved hybrid recommendation algorithm is better.

A series of graphene-enveloped sulfur (G/S) composites with different sulfur particle sizes and high sulfur contents of 82 wt% are synthesized using a double solvent approach for lithium–sulfur batteries. This double solvent approach is facile, low cost, and effective in preparing graphene–sulfur composites for large-scale production. Scanning electron microscopy and energy dispersive X-ray spectroscopy mapping were used to verify the structure and composition of the G/S composites. The graphene-coating layers not only provide a conductive carbon matrix surrounding the sulfur particles but also prevent the soluble polysulfide intermediates dissolving into the electrolyte. The sizes of sulfur particles can be controlled by adjusting the ratios of double solvent (CS2/alcohol) and may further affect the electrochemical behavior. When used as cathode materials for lithium–sulfur batteries, the G/S-200 composite with the smallest sulfur particle size shows an initial discharge capacity of 1068.5 mAh g−1 and retains 729.5 mAh g−1 after 100 cycles at 0.1C. This novel double solvent method is a promising approach to obtain other carbon sulfur composites.

A nanostructured magnesium silicide (Mg 2 Si) was fabricated via heating SiC substrate in an Mg vapor by reactive deposition techniques and characterized by Scanning electron microscopy (SEM) and X-ray Diffractometer (XRD). The electrochemical performances were tested by a galvanostatically charge/discharge method. A maximum discharge capacity of 365 mA h/g was measured by Mg 2 Si nanoparticle electrode with a good cycle performance. A Mg 2 Si thin film was also prepared by the reaction of Si substrate with Mg vapor for comparison. The Mg 2 Si film showed a high initial discharge capacity up to 2238 mA h/g. However, the capacity decayed quickly to less than 20 mA h/g after 20 cycles. This work provides a feasible way to fabricate the silicide based nanostructured materials for Li ion battery.

Mg2Si/Si nanocomposites, consisting of Si nanosheet bundles and Mg2Si deposits formed on the Si nanosheet bundles, were formed by the thermal annealing of CaSi2 powders in MgCl2 vapor. Mg atoms are deposited on the Si nanosheet bundles, and the surface of the nanosheets were partially transformed into the Mg2Si phase during the thermal treatment. The Mg2Si/Si composites were also synthesized on Si(111) substrates. The structural and photoluminescence (PL) properties of the composites were characterized. The Mg2Si deposits were inhomogeneously distributed on the Si nanosheets. Furthermore, the Si-based nanosheets consisted of disordered thinner Si layers, and a disordered superlattice-like layered structural model is shown. The PL emissions in the visible region were clearly observed, and the temperature and the excitation intensity dependences of the emissions were characterized. It was found that the structural modification of the Si nanosheet bundles to form the composites with Mg2Si deposits affected the emission property of the Si nanosheets. The luminescence mechanism of the composite was discussed.

Si-based nanosheet bundles were synthesized by the extraction of Ca atoms from CaSi2 microwalls grown on Si substrates by inositol hexakisphosphate solution or thermal treatment in FeCl2 vapor. The structural and photoluminescence properties of the Si-based nanosheet bundles were examined. The photoluminescence emissions in the visible region were clearly observed, and the temperature and excitation intensity dependences of the emissions were characterized. The observed Si-based nanosheets consist of thin Si layers, and a superlattice-like layered structural model is proposed to describe the Si-based nanosheet bundle structures and their photoluminescence property. The photoluminescence property of the nanosheets significantly depends on their treatment process. The luminescence mechanism of the nanosheets was discussed.