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A series of cyclic energetic derivatives based on nitroguanidine and 1,1-diamino-2,2-dinitroethene were theoretically designed. The spatial structures, infrared spectrometry, heats of formation, electronic structures, detonation properties, and thermal stabilities of these designed compounds were fully investigated by density functional theory. It is found that all the designed compounds have moderate stabilities (bond dissociation energies range from 11.3 to 99.0 kJ mol-1), high crystal densities (from 1.9589 to 2.00188 g cm-3), high positive heats of formation (from 649.6 to 1060.8 kJ mol-1) and high positive heats of detonation (from 1074.77 to 1332.06 cal g-1) which lead to the excellent detonation properties (detonation velocities range from 8.71 to 9.05 km s-1 while detonation pressures range from 35.47 to 38.55 GPa). Electronic structures such as electrostatic potentials on the surface, electronic densities, highest occupied molecular orbitals, lowest unoccupied molecular orbitals and their energy gaps were also simulated to give a better understanding of chemical and physical properties of these compounds. All the data may shine lights on the explosive searching and synthesis.

Objectives: to investigate the quality of life and the associated factors on left behind elderly in rural China., Method: the research was conducted cluster sampling to select 456 elderly left behind when family members migrated out of rural China to participate in a cross-sectional study by completing a general data questionnaire and Quality of Life questionnaire., Results: 91.5% of the elderly requested psychological counseling and education. For the elderly, scores for mental health (39.56±13.73) were significantly lower compared with Chinese standard data (61.6±13.7) (P<0.001). Age, chronic disease type, gender, residence pattern and economic support from children were the main psychological factors influencing this population., Conclusion: mental health is the most important factor influencing quality of life of elderly left behind when family members migrated out of rural China. Our study suggested a need to widely establish a general practitioner team for psychological intervention for improving rural elderly people's Quality of Life level, especially in the psychological domain.