Single-crystalline α-AlO nanobelts were synthesized by high-temperature chemical vapor deposition in a high-purity H atmosphere. The crystalline planes for the upper and side surfaces of the nanobelts were [Formula: see text] and [Formula: see text] and the orientations along height, length and width directions were [Formula: see text] [Formula: see text] and [Formula: see text] respectively. The formation of such a unique structure was dependent on the strong reducing atmosphere used in the growth process, and the deactivation of the [Formula: see text] plane by hydrogen could be the primary cause. The elastic modulus of the nanobelts was measured using a thermal resonance method. The moduli for the nanobelts were about 320 GPa for thicknesses above 40 nm, and slightly increased to 356 GPa as the thickness decreased to 31 nm. The slightly low modulus values compared to the theoretical value of 371 GPa is attributed to oxygen vacancies within the nanobelts, while the increase in modulus with decreased thickness comes from the stiffening effect caused by surface relaxation.

Hollow carbon nanospheres (HCNSs) were fabricated by annealing the Cu−C core−shell nanoparticles at 1250 °C in vacuum. The as-obtained HCNSs have ultrathin shell of 1−3 nm in thickness, small size of about 20 nm in diameter, high surface area of 300 m 2 g −1 , and ultrasmall pores below 5 nm within the C shells. The HCNSs exhibit excellent electrochemical performance as anode materials for lithium-ion batteries. A reversible capacity of 400 mAh g −1 and capacity retention of nearly 100% are achieved at the current density of 186 mA g −1 after 100 charging−discharging cycles. The high reversible capacity, improved high-rate capability, and outstanding cycling stability could be attributed to their unique structural characteristics including the extremely small diameter, the high surface area and the hollow structure with porous, ultrathin shell.

Fe3C-C core-shell nanoparticles were fabricated on a large scale by metal-organic chemical vapor deposition at 700 °C with ferric acetylacetonate as the precursor. Analysis results of x-ray diffraction, transmission electron microscope and Raman spectroscope showed that the Fe3C cores with an average diameter of ∼35 nm were capsulated by the graphite-like C layers with the thickness of 2-5 nm. The comparative experiments revealed that considerable Fe3O4-Fe3C core-shell nanoparticles and C nanotubes were generated simultaneously at 600 and 800 °C, respectively. A formation mechanism was proposed for the as-synthesized core-shell nanostructures, based on the temperature-dependent catalytic activity of Fe3C nanoclusters and the coalescence process of Fe3C-C nanoclusters. The Fe3C-C core-shell nanoparticles exhibited a saturation magnetization of 23.6 emu g(-1) and a coercivity of 550 Oe at room temperature.

In order to improve the loading effect of thin seam shearer, this paper takes MG450 / 1050-WD shearer, drum diameter of 1200 mm and section depth of 750 mm as the research object, establishes the simulation analysis model of shearer and scraper conveyor through discrete element method, and studies the influence law of drum structural parameters and motion parameters on the loading effect of shearer. It is found that under the selected working conditions, the installed performance of the shearer is the best when the helix angle is 14° and the drum speed is 45rpm.

In order to improve the design efficiency of the shearer drum and achieve rapid optimization, it is proposed to establish a parametric design system for the shearer spiral drum centered on design, optimization system and parametric modeling technology. The overall idea of implementing the system, the function and design analysis of each module are expounded, and the key technologies are discussed. Using Solidworks as the platform, the parametric design of the shearer spiral drum was developed with VB.Net, including the modification of the drum size, the automatic drawing of the cutting diagram, the load calculation of the pick and the automatic generation of the loading blade parts and their unfolding engineering drawings. Finally, it was verified with a 1800x630 roller. Tests prove that the system can quickly optimize the shearer drum, improve the speed and accuracy of drum development, and reduce costs.