Mechanistic aspects of the comparative oscillatory electrochemical oxidation of formic acid and methanol on platinum electrode

Journal of Solid State Electrochemistry - The characteristics of the electrochemical oscillations that emerge along the catalytic oxidation of small organic molecules critically depend on the...     

Observation of Fano resonance and classical analog of electromagnetically induced transparency in toroidal metamaterials

Toroidal multipoles have recently been explored in various scientific communities, ranging from atomic and molecular physics, electrodynamics, and solid‐state physics to biology. Here we experimentally and numerically demonstrate a three‐dimensionsal toroidal metamaterial where two different toroidal dipoles along orthogonal directions have been observed. The chosen toroidal metamaterial also simultaneously supports Fano resonance and the classical analog of electromagnetically induced transparency (EIT) phenomena in the transmission spectra that originate from the electric–toroidal dipole and electric–magnetic dipole destructive interference. The intriguing properties of the toroidal resonances may open up avenues for applications in toroidal moments generator, sensing and slow‐light devices.     

Harmonic manifolds with minimal horospheres

For a non-compact harmonic manifold M, we establish an integral formula for the derivative of a harmonic function on M. As an application we show that for the harmonic spaces having minimal horospheres, bounded harmonic functions are constant. The main result of this article states that the harmonic spaces having polynomial volume growth are flat. In other words, if the volume density function Θ of M has polynomial growth, then M is flat. This partially answers a question of Szabo namely, which density functions determine the metric of a harmonic manifold. Finally, we give some natural conditions which ensure polynomial growth of the volume function.     

Evidence for an anomalous redox ionic pair between Ru and Mn in SrRu0.5Mn0.5O3: an X-ray absorption spectroscopy approach

X-ray absorption spectroscopy studies of the polycrystalline SrRu0.5Mn0.5O3 have been performed at Ru, Mn-L2,3 edges. The 2p-->t2g related peak at the Ru-L2 edge is more intense than the Ru-L3 edge and a shift of the 2p-->eg related peak by approximately 0.8 eV to higher energy than that of the Ru(IV) compound, SrRuO3 is observed. In combination with a crystal field multiplet calculation approach, a possible anomalous change in the spectral features is explained based on the existence of a redox ionic pair involving Ru(IV)/Ru(v)<-->Mn(III)/Mn(IV).     

Synthesis of 2,2-dimethyl-5-hydroxy-3-(3-oxobutyl)-7-pentyl-4-chromone

Alkylation and deformylation of 2,2-dimethyl-3-hydroxymethylene-5-hydroxy-7-pentyl-4-chromone occurs in the same step to give the title compound.     

Microwave–assisted synthesis of <Emphasis Type="Italic">submicrometer</Emphasis> GaO(OH) and Ga<Subscript>2</Subscript>O<Subscript>3</Subscript> rods

Submicrometer sized gallium oxide hydroxide (GaO(OH)) and gallium oxide (Ga₂O₃) rods have been successfully fabricated on a large scale by refluxing an aqueous solution of Ga(NO₃)₃ and NH₄OH in a simple domestic microwave oven (DMO). The structures, morphologies, compositions and physical properties of the as–synthesized and calcined products have been characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), selected area energy dispersive X-ray spectroscopy (SAEDS), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), and energy dispersive X-ray (EDX) analysis. TEM images show that submicrometer sized as–synthesized Ga O(OH) rods have diameters of 0.3–0.5 m and lengths of 3.2–3.5 m. The calcined product consists of submicrometer rods with diameters of 0.4–0.5 m and lengths of 5–5.5 m. XRD, EDX and SAED analysis together indicate that the as–synthesized product has an orthorhombic gallium oxide hydroxide (GaO(OH)) crystal structure, and that the calcined product is rhombohedral Ga₂O₃. A possible mechanism for the formation of submicrometer sized GaO(OH) rods is discussed briefly.