Fude Nie

Preparation and Characterization of Nano-NTO Explosive

Nano-NTO particles (5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one) were prepared by the spray freezing into liquid (SFL) method. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), thermogravimetric analysis (TG), and differential scanning calorimetry (DSC) analysis methods were used to characterize the particles. The results show that the NTO particles have an elongated shape with a size of 70–90 nm. With NTO particle size reduced to the nanometer range, the XRD diffraction peaks broaden and the peak intensity weakens. Nano-NTO decomposes at a lower temperature and is less sensitive to impact stimuli compared with micro-NTO.

Research on KOH/La-Ba-Al2O3 catalysts for biodiesel production via transesterification from microalgae oil

Alumina supports modified by lanthanum (La) and barium (Ba) were prepared by peptization. Catalysts with different KOH contents supported on modified alumina were prepared by impregnation method. Various techniques, including N2 adsorption-desorption (Brunauer-Emmet-Teller method, BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), and fourier transform infrared absorption spectroscopy (FT-IR). Catalytic activity for microalgae oil conversion to methyl ester via transesterification was evaluated and analyzed by GC-MS and GC. BET results showed that the support possessed high specific surface area, suitable pore volume and pore size distribution. Activity results indicated that the catalyst with 25 wt% KOH showed the best activity for microalgae oil conversion. XRD and SEM results revealed that Al–O–K compound was the active phase for microalgae oil conversion. The agglomeration and changing of pore structure should be the main reasons for the catalyst deactivation when KOH content was higher than 30 wt%.

Influence of crystal characteristics on the shock sensitivities of cyclotrimethylene trinitramine, cyclotetramethylene tetranitramine, and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetra-cyclo[5,5,0,03,1105,9]dodecane immersed in liquid

The shock sensitivities of differently qualified cyclotrimethylene trinitramine (RDX), cyclotetramethylene tetranitramine(HMX), and 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetra-cyclo[5,5,0,03,1105,9]dodecane (CL-20) immersed in liquid were determined by the large-scale gap tests, for systemic discussion on the influences of crystal characteristics on them. As a result, it shows that (1) the immersion of crystals in liquid leads to an obvious sensitivity decrease; (2) for all three explosives, their shock sensitivities are lowered with increasing their crystal apparent densities or decreasing their particle sizes, and almost not affected by particle morphologies; (3) the crystal twins are readily formed for HMX and the most distinct factor influencing its shock sensitivities; (4) it is found that the crystal apparent density affects most obviously the shock sensitivities for RDX and CL-20; and (5) CL-20, HMX, and RDX are less and less sensitive to shock, suggesting chemical components are also a dete...

Controlled facile synthesis, growth mechanism, and exothermic properties of large-area Co3O4 nanowalls and nanowires on silicon substrates

Co3O4 nanowalls and nanowires have been synthesized onto silicon substrates by low-temperature thermal oxidation of sputtered Co thin films in static air. The synthesis method is very simple and suitable for large-scale fabrication. The effects of the thermal oxidation temperature and duration on the size, amount, and length of the nanowires and nanowalls are systematically investigated both by scanning electron microscopy characterization and differential scanning calorimetry thermal analysis. It is found that the Co/CoO oxidation and Co3O4 decomposition are important factors contributing to the growth of the Co3O4 nanowalls and nanowires. The mechanical adhesion between the Co3O4 nanowalls/nanowires/film and the silicon substrate is observed to be very strong, which is beneficial for many practical applications. Based on the experimental observations, the detailed growth mechanisms of the nanowalls and nanowires are presented. Finally, the promising novel exothermic reaction properties of the Co3O4 nano...