THE AREA INTEGRAL ON NEGATIVE CURVATURE SPACE FORM

In this note, we show that the area integral of positive harmonic functions on a constant negative curvature space form is almost everywhere finite with respect to a harmonic measure on S(∞).     

One stone kills four birds: a novel diazaperinone 12H-pyrazino[2′,3′:3,4]pyrrolo[1,2-a]perimidin-12-one recognizes four different metal ions

A novel diazaperinone 12H-pyrazino[2′,3′:3,4]pyrrolo[1,2-a]perimidin-12-one has been successfully synthesized through a one-step condensation. Single crystal X-ray analysis shows that the product is of planar structure with strong π?π interactions and H-bonding. Interestingly, the 12H-pyrazino[2′,3′:3,4]pyrrolo[1,2-a]perimidin-12-one can recognize three different metal cations Cu²⁺, Ag⁺ and Hg²⁺ via naked eye visualization, and shows turn-on fluorescence for Fe³⁺ and Ag⁺ among the 22 metal cations.     

Longitudinal coupling effect in microfiber Bragg gratings

We theoretically present longitudinal coupling effect (LCE) in air-cladding microfiber Bragg gratings (MFBGs). Distinct from conventional weakly-guiding optical fibers, large longitudinal electric field (E_z) exists in wavelength-scale microfibers. Due to LCE, MFBG reflectivity can be reduced by more than 30% within the band-gap and the full width at half maximum (FWHM) is obviously narrowed. This theoretical analytical work is instructive to precisely design and fabricate MFBGs that are promising in the areas of optical sensing and nanophotonics.     

An anthracene-modified β-cyclodextrin that distinguishes adenosine phosphates fluorescently

A β-cyclodextrin derivative (AnCD) with the diamino anthracene was presented and studied, which can distinguish AMP from ADP and ATP via fluorescence titration.