Connectedness of the invertibles in certain nest algebras of order type ω

We solve the connectedness problem for a class of nests of order type ω with finite dimensional atoms.     

A Light-Harvesting/Charge-Separation Model with Energy Gradient Made of Assemblies of meta-Pyridyl Zinc Porphyrins

Self-assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular-level devices. Herein, zinc porphyrin derivatives bearing a meta-pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct ¹H NMR spectrum in CDCl₃, which allowed the supramolecular structure in solution to be probed in detail. Ring-current-induced chemical-shift changes in the ¹H NMR spectrum, together with vapor-pressure osmometry and diffusion-ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light-harvesting/charge-separation system in which an energy gradient is incorporated and reductive quenching occurs.     

An improved watermarking method based on double random phase encoding technique

An improved watermarking method, based on the double random phase encoding technique and the cascaded-phases iterative algorithm and random-phase-shift algorithm, is proposed. This method can significantly reduce the needs of watermarking information storage for different multimedia products, and provide a reasonable criterion of determining the authenticity of a product for the copyright owner. This method can also be applied to track the source of copies. The effectiveness of this method was verified through numerical simulations.     

Slow light in a simple metamaterial structure constructed by cut and continuous metal strips

Recently, slow light in metamaterials has been investigated based on the coupling between two quasi-bound states, in classic analogue of electromagnetically induced transparency in atomic systems. Here we demonstrate the feasibility in achieving slow light in metamaterials, based on the mechanism of coupling between a quasi-bound state and a continuum state. The theoretical prediction by a two-particle model is in good agreement with the experimental result in the metamaterial composed of the cut and continuous metal strips. The present work illustrates the versatility of metamaterials, implying the great potential in many applications.