Dinitrophenyl-oxadiazole compounds:Design strategy,synthesis,and properties of a series of new melt-cast explosives

Melt-cast explosives are the most widely used energetic materials in military composite explosives,researchers have been unremittingly exploring high-energy and insensitive melt-cast explosives.In this work,a series of dinitrophenyl-oxadiazole compounds were designed and prepared.These compounds have an ideal low melting point(80-97℃),good detonation performance(detonation velocity D=6455-6971 m/s,detonation pressure P=18-19 GPa)and extreme insensitive nature(impact sensitivity≥60 J,friction sensitivity>360 N).All these compounds were well characterized by nuclear magnetic resonance,fourier transform infrared spectroscopy,elemental analysis.Compounds 2,3 were unambiguously confirmed by X-ray single crystal diffraction analysis.As a result,their overall properties are superior to traditional melt-cast explosives trinitrotoluene(TNT)and dinitroanisole(DNAN)which may have excellent potential applications in insensitive melt-cast explosives.

Differences in Non-suicidal Self-injury Behaviors between Unipolar Depression and Bipolar Depression in Adolescent Outpatients

Objective Non-suicidal self-injury(NSSI)has a higher prevalence in adolescents with depressive disorders than in community adolescents.This study examined the differences in NSSI behaviors between adolescents with unipolar depression(UD)and those with bipolar depression(BD).Methods Adolescents with UD or BD were recruited from 20 general or psychiatric hospitals across China.The methods,frequency,and function of NSSI were assessed by Functional Assessment of Self-Mutilation.The Beck Suicide Ideation Scale was used to evaluate adolescents’suicidal ideation,and the 10-item Kessler Psychological Distress Scale to estimate the anxiety and depression symptoms.Results The UD group had higher levels of depression(19.16 vs.17.37,F=15.23,P<0.001)and anxiety symptoms(17.73 vs.16.70,F=5.00,P=0.026)than the BD group.Adolescents with BD had a longer course of NSSI than those with UD(2.00 vs.1.00 year,Z=−3.39,P=0.001).There were no statistical differences in the frequency and the number of methods of NSSI between the UD and BD groups.Depression(r=0.408,P<0.01)and anxiety(r=0.391,P<0.01)were significantly and positively related to NSSI frequency.Conclusion Adolescents with BD had a longer course of NSSI than those with UD.More importantly,NSSI frequency were positively and strongly correlated with depression and anxiety symptoms,indicating the importance of adequate treatment of depression and anxiety in preventing and intervening adolescents’NSSI behaviors.

Synthesis of energetic coordination polymers based on 4-nitropyrazole by solid-melt crystallization in non-ionization condition

Based on the theory of crystallization,a solvent-free solid-liquid phase crystallization method called solid-melt crystallization was designed to prepare energetic coordination polymers.Two target compounds[Cu(NPyz)_(4)NO_(3)]·NO_(3)(ECPs-1)and Cu(NPyz)_(4)(ClO_(4))_(2)(ECCs-2)were prepared through programmed heating and cooling by using 4-nitropyrazole(NPyz),(Cu(NO_(3))_(2)·5H_(2)O and Cu(ClO_(4))_(2)·5H_(2)O) as raw materials.In addition,crystallization pre-experiments and annealing experiments also verified the feasibility of the method.Their structures were confirmed by IR,elemental analysis,single-crystal X-ray diffraction and powder X-ray diffraction.The physicochemical properties and sensitivity test results showed that ECCs-2 has better thermal stability(T_(d)=221℃),while ECPs-1 is less sensitive to mechanical stimuli(IS=12 J,FS=240 N).Calculations based on EXPLO5 and the Kamlet-Jacobs equation showed that ECCs-2 has more considerable detonation performance(P=25.2 GPa,D=7.5 km/s).In comparison,the more intuitive results from the HN test,flame test,thermal resistance test and lead plate explosion test revealed that ECCs-2 has an“acceptable”detonation performance.The laser detonation test also showed that ECCs-2 is a promising excellent laser detonation material(E=408 mJ,P=24 W,τ=17 ms).

Highly Selective Photocatalytic Conversion of Glucose on Holo-Symmetrically Spherical Three-Dimensionally Ordered Macroporous Heterojunction Photonic Crystal

Photocatalytic conversion of biomass is considered an effective,clean,and environmentally friendly route to obtain high-valued chemicals and hydrogen.However,the limited conversion efficiency and poor selectivity are still the main bottlenecks for photocatalytic biomass conversion.Herein,we report the highly selective photocatalytic conversion of glucose solution on holosymmetrically spherical three-dimensionally ordered macroporous TiO_(2)-CdSe heterojunction photonic crystal structure(s-TCS).The obtained s-TCS photocatalysts show excellent stability and strong light harvesting,uniform mass diffusion and exchange,and efficient photogenerated electrons/holes separation and utilization.The optimized s-TCS-4 photocatalyst displays the highest photocatalytic performance for glucose oxidation and hydrogen production.The glucose conversion,lactic acid selectivity,and yield on s-TCS-4 are about 95.9%,94.3%,and 96.4%,respectively.The photocatalytic production of lactic acid for s-TCS-4(18.5 g/L)is 2.3 times higher than the pure spherical TiO_(2) photonic crystal without CdSe(s-TiO_(2),8.1 g/L),and the hydrogen production rate of s-TCS-4 is 9.4 times that of s-TiO_(2).For the first time,we reveal that the photocatalytic conversion of glucose to lactic acid is a third-order and four-electron-involved reaction.This work could shed some new light on the efficient photocatalysis conversion of biomass to highly value-added products with high selectivity and yield,and simultaneously sustainable hydrogen evolution.