Theoretical Studies on Structures and Relative Stability for Polynitrohexaazaadamantanes

The density function theory at the B3LYP/6-31G＊ level was employed to study the structures, including the total energies （EZpE）, the geometries, the oxygen balances （OB100）, the dipole moments, of polynitrohexaazaadamantanes （PNHAAs） and the potential candidates of high energy density compounds （HEDCs）. The structural parameters of PNHAAs, such as the the maximum N-NO2 hond length （LBmax）, the least N-N Mulliken population （BN-N）, the least negative charge on the nitro group （QNO2） and OB100, were studied to predict their relative stability or sensitivity （the easiness for initiating a detonation, high sensitivity means low stability）. It was found that the same conclusion was drawn from the four parameters. With the number of nitro groups increasing, the stabilities of these compounds decrease. OB100 failed in identifying the isomers, but the EZpE energy and the dipole moment were considered to give more reliable results for the isomers.

Effects of elevated CO_2 levels on root morphological traits and Cd uptakes of two Lolium species under Cd stress

This study was conducted to investigate the combined effects of elevated CO2 levels and cadmium (Cd) on the root morphological traits and Cd accumulation in Lolium multiflorum Lam.and Lolium perenne L.exposed to two CO2 levels (360 and 1000 μl/L) and three Cd levels (0,4,and 16 mg/L) under hydroponic conditions.The results show that elevated levels of CO2 increased shoot biomass more,compared to root biomass,but decreased Cd concentrations in all plant tissues.Cd exposure caused toxicity to both Lolium species,as shown by the restrictions of the root morphological parameters including root length,surface area,volume,and tip numbers.These parameters were significantly higher under elevated levels of CO2 than under ambient CO2,especially for the number of fine roots.The increases in magnitudes of those parameters triggered by elevated levels of CO2 under Cd stress were more than those under non-Cd stress,suggesting an ameliorated Cd stress under elevated levels of CO2.The total Cd uptake per pot,calculated on the basis of biomass,was significantly greater under elevated levels of CO2 than under ambient CO2.Ameliorated Cd toxicity,decreased Cd concentration,and altered root morphological traits in both Lolium species under elevated levels of CO2 may have implications in food safety and phytoremediation.

The smart precursors of energetic–energetic cocrystals from eutectic precursors

The selected 18 energetic compounds were theoretically investigated by using the density functional theory（DFT） quantum mechanical code,DMol3,and the Hansen solubility parameters（HSPs） analyses.The results showed that 4-nitrotoluene,4-nitrophenol,N N0-dimethyl-N N0-diphenylurea and N N0-diethyl-N N0-diphenylurea contain relatively electron-rich aromatic rings.Four satisfactory energetic precursors with electron-rich rings were quickly and effectively found by electrostatic potential（ESP）surfaces and HSPs analyses.The results also indicated that the absolute value of the lowest unoccupied molecular orbital（LUMO） of the energetic precursors with electron-rich rings often was less than3.00 eV,and the absolute value of LUMO of the energetic precursors with electron deficient rings was often more than 3.00 eV.Additionally,we found that with at least two eutectic points was a prerequisite for two precursors to form a cocrystal.