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Five kinds of graphene nanoplatelet-modified explosive lead styphnate composites (GLS) have been synthesized with different GNPs content from 0.1 to 2.0 mass% and characterized by SEM, XRD and Raman spectra. The initial thermal decomposition behaviours were studied by DPTA, and the complete thermal decompositions were studied by DSC and TG for the everlasting thermal stability of explosives in storage and application. The effects of GNP contents on thermal decomposition were investigated. The evolved gas amount from DPTA test indicates that GLS 1.0 % has the best thermal stability at ambient storage conditions. According to TG and DSC tests, the characteristic temperatures of thermal decomposition ( T and T), the thermodynamic parameters (Δ S, Δ H and Δ G), the kinetic parameters ( E and A) also confirmed this view. The results indicate that the GNP plays two opposite roles in their thermal decomposition processes, the catalysis reaction and hindering thermal conduction. [ABSTRACT FROM AUTHOR]

First-principles methods using the TPSS density functional level of theory with the basis set 6-31G** were applied to study (5-cyanotetrazolato-N) pentaammine cobalt (III) perchlorate (CP) and Ni, Fe and Zn analogues in the gas phase. The optimized lowest-energy geometry of CP was calculated from reported experimental structural data using the TPSS method. The calculated values are in good agreement with those measured by X-ray diffraction. Ni, Fe and Zn analogues were constructed and calculated on the same basis. NBO results showed that the metal-ligand interactions have covalent character. Donor-acceptor analyses predicted that the delocalization energy E decreases from Co to Zn, so the covalent nature of the complexes increases in the order Co>Fe>Ni>Zn. In addition, HOMO-LUMO composition was investigated to determine the stability of the title compounds. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

ZnO microcrystals are synthesized through a facile solution method and characterized by field-emission scanning electron microscopy, transmission electron microscopy, selected area electron diffraction and X-ray diffraction. The ethanol sensing properties of these microcrystals are investigated by spin-coating them on a silicon substrate with Pt electrodes to fabricate a micro-structure sensor. The sensitivity is up to 8 when the sensor is exposed to 50 ppm ethanol, and the response time and recovery time are 10 s and 20 s, respectively. A contact-controlled model is established to explain the sensing properties of the microcrystals, which provides another approach to realize high-performance gas sensors. [ABSTRACT FROM AUTHOR]