Diffraction-induced spectral anomalies for information encoding and information hiding - Possibilities and limitations

It has been shown both theoretically and experimentally that drastic spectral changes take place around phase singularity and the shift in the spectral lines gives rise to the phenomenon called spectral switching. The shift of spectral lines towards the blue end or towards the red end of the spectrum might perhaps be used in free space communication applications. In more recent investigations, the possibility of information encoding with spectral anomalies have been discussed for two different optical systems. In this paper, we present schemes of information encoding and information hiding in the Airy pattern formed by diffraction of spatially coherent light after passing through a circular aperture. We propose a communication system that might be used to realize a new communication technique.     

Kinetics and mechanisms of oxidation by metal ions. Part XIV(1). Osmium(VIII)-catalysed oxidation of cycloalkanones by alkaline hexacyanoferrate(III)

Transition Metal Chemistry - The OsVIII-catalysed oxidation of cyclopentanone and cyclohexanone by alkaline hexacyanoferrate(III) ions is zeroth-order with respect to $ {? F_{e}(CN)_{6}^{3-}...     

An efficient and simple method for the conversion of 15-HPETE to 14,15-EPETE (lipotriene A) and 5-HPETE to leukotriene a as the methyl esters

Simple new methodology is described for the synthesis from arachidonic acid of the important eicosanoids lipotriene A methyl ester (5) and leukotriene A methyl ester (10), a key feature being the use of a novel chemical method for effecting the allylic hydroperoxide → oxiranyl carbinol rearrangement.     

General transient solutions for the four-coupled Bloch-type equations for a two-level system

When the collisional dynamics of two states under consideration for a radiative transition is different, the polarization and population relaxations in gas phase at low pressure are governed by four-, instead of three-, coupled Bloch-type equations. The general transient solutions of these four-coupled equations are solved by using the Laplace transformation technique. It has been found that an additional exponential term appears because of the effect. This is also responsible for the non-exponential character in the decay signal of a transient microwave pulse experiment, besides other factors reported earlier.     

Organic Derivatives of Tin. III. Reactions of Trialkyltin Ethoxide with Alkanolamines

The reactions oi tributyltin ethoxide, Bu₃SnOEt, with N,N-dialkylalkanolamines, HORNR₂ (where R = ? CH₂ · CH₂? , ? CH₂ · CH₂ · CH₂? and ? CH₂ · MeCH? ; R = ? CH₃ and ? C₂H₅) give Bu₃SnORNR₂. In reactions of Bu₃SnOEt with N-methylethanolamine, HOCH₂ · CH₂NHMe, and various alkanolamines, HO · R · NH₂, (where R = ? CH₂ · CH₂? ? CH₂ · CH₂ · CH₂? , ? CHMe · CH₂? ? CH₂ · Me₂C? and ? CH₂ · CH · CH₂ · Me) both the hydroxy as well as the amino groups show reactivity to form products of the type: Bu₃SnOCH₂ · CH₂NHMe, Bu₃SnOCH₂ · CH₂NMeSnBu₃, Bu₃SnO · R · NH₂, Bu₃SnO · R · NHSnBu₃, and Bu₃SnO · R · N(SnBu₃)₂, respectively. The reaction between Bu₃SnOEt and o-aminophenol yields only Bu₃SnO · C₆H₄NH₂.