2-μm emission performance of Tm~(3+)-Ho~(3+) co-doped tellurite glasses

The emission properties of 2-μm region fluorescence of Tm~(3+)-Ho~(3+) co-doped tellurite glasses are investigated. Introducing F~- ions to the composition of tellurite glasses plays a positive effect on the 2-μm emission.A maximum intensity of 2-μm emission is achieved when 1.5-mol%Tm_2O_3 and l-mol% Ho_2_O3 concentration are doped in the glasses.The emission cross section and gain coefficient of the ~5I_8→~5I_7 transition of Ho~(3+) are calculated.The emission cross section has a maximum of 1.29×10~(-2...     

Effects of annealing on luminescence efficiency of large-size YAG:Ce crystal grown by temperature gradient techniques

<正>YAG:Ce crystal with a diameter of 110 mm is successfully grown by the temperature gradient technique (TGT).The effects of annealing on the luminescence efficiency of YAG:Ce crystal are investigated,and the optimal annealing temperature and atmosphere are obtained.The mechanism of variation behavior of the luminescence efficiency of YAG:Ce under different annealing conditions is discussed and some details on the luminescence associated with color centers are analyzed.     

Numerical simulations of the impact of wavefront phase distortions of pump on the beam quality of OPA

<正>A numerical model of optical parametric amplification(OPA) is introduced to investigate the impact of wavefront phase distortion of pump on the beam quality of signal.Numerical results show that the unidentical walk-off directions of the pump and the idler waves are the main factors leading to the transfer of wavefront phase distortions of the pump to the signal,and by reducing the angle between the two directions,the beam quality factor(M~2) can be greatly decreased and hence the good beam quality of the signal can be maintained.     

Rapid formation of metal-organic nano-capsules gives new insight into the self-assembly process

Metal-organic pyrogallol[4]arene nano-capsules, mixed pyrogallol[4]arene nano-capsules, and mixed metal analogues have been rapidly synthesised by addition of excess copper nitrate to a methanol solution of the corresponding macrocycle(s) (or gallium nano-capsules for the mixed metal system); improved solubility allows for thorough study and elucidation of the assembly process for these discrete metal-organic assemblies.     

Application of MELC and MEEKC for the Analysis of Paracetamol and Related Impurities in Suppositories

Rapid MELC and MEEKC methods were developed for paracetamol suppository assay. MELC methods for paracetamol analysis and for separation of paracetamol and its impurities were previously reported. In this study, further development of MEEKC methods and a MELC method using anionic and cationic microemulsions gave excellent validation results for paracetamol content in suppositories. SDS Microemulsion instability resulted in poor reproducibility for impurity separations using gradient elution. A novel isocratic CTAB MELC method achieved reproducible separation of paracetamol and its impurities at 0.1% levels. MEEKC methods using SDS and CTAB microemulsions resolved all of the impurities however detection at 0.1% levels was not possible. These methods gave significant benefits in terms of reduced sample pre-treatment requirements. CTAB microemulsions had greater solubilising power than their SDS equivalent and were more stable due to their longer alkyl chain length.     

Room temperature synthesis of surface-functionalised boron nanoparticles

Capped boron nanoparticles have been synthesized at room temperature by a simple route that does not involve the use of flammable boranes.     

The non-solvability by radicals of generic 3-connected planar Laman graphs

We show that planar embeddable -connected Laman graphs are generically non-soluble. A Laman graph represents a configuration of points on the Euclidean plane with just enough distance specifications between them to ensure rigidity. Formally, a Laman graph is a maximally independent graph, that is, one that satisfies the vertex-edge count together with a corresponding inequality for each subgraph. The following main theorem of the paper resolves a conjecture of Owen (1991) in the planar case. Let be a maximally independent -connected planar graph, with more than 3 vertices, together with a realisable assignment of generic distances for the edges which includes a normalised unit length (base) edge. Then, for any solution configuration for these distances on a plane, with the base edge vertices placed at rational points, not all coordinates of the vertices lie in a radical extension of the distance field.