Ca8Mg（SiO4）4Cl2∶Eu2+,Ce3+,Mn2+绿色荧光粉发光性能及其应用研究

利用高温固相法,合成出Eu2+、Ce3+、Mn2+共掺的Ca8Mg(SiO4)4Cl2系列绿色荧光粉。通过XRD表征了这些荧光粉的结构,通过分子荧光光谱仪研究了它们的室温发光性能。首先调查了Eu2+掺杂的Ca8Mg(SiO4)4Cl2绿色荧光粉发光性能,随后引入Ce3+、Mn2+提高了Ca8Mg(SiO4)4Cl2∶Eu2+在紫外光区的吸收强度及绿光发射强度。最后将筛选出来的荧光粉与InGaN-LED芯片组装制作成单一绿光LED器件,利用Ca7.8215MgSi4O16Cl2∶0.0525Eu2+,0.056Ce3+,0.070Mn2+所制作成的绿光LED器件发光最强,在20mA电流激发下,此LED发很强的绿光,其电致发光光谱所对应的色坐标值为:x=0.26,y=0.55。     

A novel ε-HNIW-based insensitive high explosive incorporated with reduced graphene oxide

A novel ε-HNIW-based explosive formula with low sensitive and high energy was developed by systematically researching the processes of recrystallization, granularity gradation, and coating of ε-HNIW and option of energetic deterrents. The grain size and morphology of HNIW crystals were modified by solvent/antisolvent recrystallization. The ε-HNIW particles were graded and coated by emulsion polymerization method with 551 glue. The binder reduced the mechanical sensitivity of ε-HNIW significantly and showed good compatibility with ε-HNIW, but also weakened the decomposition enthalpy. With the purpose of developing new energetic deterrents in insensitive high explosive formulations, novel carbon materials graphene oxide (GO) and reduced graphene oxide (rGO) were prepared and incorporated in plastic-bonded explosive (PBX) formulations. For comparison, the effects of conventional deterrent flake graphite were also involved. It turned out that the mechanical sensitivities of ε-HNIW/551 glue have all reduced to some extent with the incorporation of graphite, GO, and rGO. Flake graphite induced the PBX decompose earlier slightly and weaken the heat output. The addition of GO resulted in noticeable antedating decomposition of ε-HNIW/551 glue although remarkably increased the decomposition heat. The formula of ε-HNIW/551 glue/rGO provided a moderate growth in decomposition heat and best thermal stability. In slow cook-off tests, the formulas of ε-HNIW/551 glue and ε-HNIW/551 glue/rGO showed good thermal stability and might be qualified to apply safely under 200 °C. Comprehensively considering the mechanical sensitivity, thermals stability, energy performance, and practical application, ε-HNIW/551 glue/rGO is supposed to be an eligible insensitive high-energy PBX formula.     

Pumping through Porous Hydrophobic/Oleophilic Materials: An Alternative Technology for Oil Spill Remediation

Recently, porous hydrophobic/oleophilic materials (PHOMs) have been shown to be the most promising candidates for cleaning up oil spills; however, due to their limited absorption capacity, a large quantity of PHOMs would be consumed in oil spill remediation, causing serious economic problems. In addition, the complicated and time‐consuming process of oil recovery from these sorbents is also an obstacle to their practical application. To solve the above problems, we apply external pumping on PHOMs to realize the continuous collection of oil spills in situ from the water surface with high speed and efficiency. Based on this novel design, oil/water separation and oil collection can be simultaneously achieved in the remediation of oil spills, and the oil sorption capacity is no longer limited to the volume and weight of the sorption material. This novel external pumping technique may bring PHOMs a step closer to practical application in oil spill remediation.     

Highly Enantioselective Ring‐Opening Reactions of Aziridines with Indole and Its Application in the Building of C3‐Halogenated Pyrroloindolines

A magnesium‐catalyzed asymmetric ring‐opening reaction of aziridine with indole has been realized by employing commercially available chiral ligands. Both of the enantiomers of the ring‐opening product could be obtained with good yields and a high level of enantioselectivity. The corresponding ring‐opening product could be further transformed to various types of enantioenriched C₃‐halogenated‐pyrroloindolines.     

Highly Luminescent N‐Doped Carbon Quantum Dots as an Effective Multifunctional Fluorescence Sensing Platform

The doping of carbon quantum dots with nitrogen provides a promising direction to improve fluorescence performance and broaden their applications in sensing systems. Herein we report a one‐pot solvothermal synthesis of N‐doped carbon quantum dots (NCQDs) and the synthesis of a series of NCQDs with different nitrogen contents. The as‐prepared NCQDs were compared with carbon quantum dots (CQDs); the introduction of nitrogen atoms largely increased the quantum yield of NCQDs and highest emission efficiency is up to 36.3 %. The fluorescence enhancement may originate from more polyaromatic structures induced by incorporated nitrogen atoms and protonation of nitrogen atoms on dots. It was found that NCQDs can act as a multifunctional fluorescence sensing platform because they can be used to detect pH values, Ag^I, and Fe^III in aqueous solution. The fluorescence intensity of NCQDs is inversely proportional to pH values across a broad range from 5.0 to 13.5, which indicates that NCQDs can be devised as an effective pH indicator. Selective detection of Ag^I and Fe^III was achieved based on their distinctive fluorescence influence because Ag^I can significantly enhance the fluorescence whereas Fe^III can greatly quench the fluorescence. The quantitative determination of Ag^I can be accomplished with NCQDs by using the linear relationship between fluorescence intensity of NCQDs and concentration of Ag^I. The sensitive detection of H₂O₂ was developed by taking advantage of the distinct quenching ability of Fe^III and Fe^II toward the fluorescence of NCQDs. Cellular toxicity test showed NCQDs still retain low toxicity to cells despite the introduction of a great deal of nitrogen atoms. Moreover, bioimaging experiments demonstrated that NCQDs have stronger resistance to photobleaching than CQDs and more excellent fluorescence labeling performance.     

Chemical and Toxicological Investigations of a Previously Unknown Poisonous European Mushroom Tricholoma terreum

The established tradition of consuming and marketing wild mushrooms has focused attention on mycotoxicity, which has become a global issue. In the present study, we describe the toxins found in a previously unknown poisonous European mushroom Tricholoma terreum. Fifteen new triterpenoids terreolides A–F ( 1 – 6 ) and saponaceolides H–P ( 8 – 16 ) were isolated from the fruiting bodies of the toxic mushroom T. terreum. Terreolides A–C ( 1 – 3 ) possessed a unique 5/6/7 trioxaspiroketal system, whereas terreolides D–F ( 4 – 6 ) possessed an unprecedented carbon skeleton. Two abundant compounds in the mushroom, saponaceolide B ( 7 ) and saponaceolide M ( 13 ), displayed acute toxicity, with LD₅₀ values of 88.3 and 63.7 mg kg^?1 when administered orally in mice. Both compounds were found to increase serum creatine kinase levels in mice, indicating that T. terreum may be the cause of mushroom poisoning ultimately leading to rhabdomyolysis.     

Phosphine‐Catalyzed [3+2] Cycloaddition Reactions of Azomethine Imines with Electron‐Deficient Alkenes: A Facile Access to Dinitrogen‐Fused Heterocycles

An efficient method for the phosphine‐catalyzed [3+2] cycloaddition reaction of azomethine imines with diphenylsulfonyl alkenes to give dinitrogen‐fused bi‐ or tricyclic heterocyclic compounds in high yields has been described. Moreover, two phenylsulfonyl groups installed on the heterocyclic products could be conveniently removed or transformed to other functional groups, making the reaction more useful.     

Rationally Investigating the Influence of T1 Location on Electroluminescence Performance of Aryl Amine Modified Phosphine Oxide Materials

The correspondence between triplet location effect and host‐localized triplet–triplet annihilation and triplet–polaron quenching effects was performed on the basis of a series of naphthyldiphenylamine (DPNA)‐modified phosphine oxide hosts. The number and ratio of DPNA and diphenylphosphine oxide was adjusted to afford symmetrical and unsymmetrical molecular structures and different electronic environments. As designed, the first triplet (T₁) states were successfully localized on the specific DPNA chromophores. Owing to the meso‐ and multi‐insulating linkages, identical optical properties and comparable electrical performance was observed, including the same first singlet (S₁) and T₁ energy levels to support the similar singlet and triplet energy transfer and the close frontier molecular orbital energy levels. This established the basis of rational investigation on T₁ location effect without interference from other optoelectronic factors.     

A New Class of Tunable Dendritic Diphosphine Ligands: Synthesis and Applications in the Ru‐Catalyzed Asymmetric Hydrogenation of Functionalized Ketones

A series of tunable G₀–G₃ dendritic 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) ligands was prepared by attaching polyaryl ether dendrons onto the four phenyl rings on the P atoms. Their ruthenium complexes were employed in the asymmetric hydrogenation of β‐ketoesters, α‐ketoesters, and α‐ketoamides to reveal the effects of dendron size on the catalytic properties. The second‐ and third‐generation catalysts exhibited excellent enantioselectivities, which are remarkably higher than those obtained from the small molecular catalysts and the first‐generation catalyst. Molecular modeling indicates that the incorporation of bulky dendritic wedges can influence the steric environments around the metal center. In addition, the ruthenium catalyst bearing a second‐generation dendritic ligand could be recycled and reused seven times without any obvious decrease in enantioselectivity.