Experimental and computational studies on zwitterionic (E)-2-(1-(2-(4-methylphenylsulfonamido)ethyliminio)ethyl) phenolate

The Schiff base compound (E)-2-(1-(2-(4-methylphenylsulfonamido)ethyliminio)ethyl) phenolate has been synthesised and characterized by IR, UV–Vis, and X-ray single-crystal determination. Ab initio calculations have been carried out for the title compound using the density functional theory (DFT) and Hartree–Fock (HF) methods at 6-31G(d) basis set. The calculated results show that the DFT/B3LYP and HF can well reproduce the structure of the title compound. Using the TD-DFT and TD-HF methods, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental ones is determined. Molecular orbital coefficient analyses reveal that the electronic transitions are mainly assigned to n → π* and π → π* electronic transitions. To investigate the tautomeric stability, optimization calculations at B3LYP/6-31G(d) level were performed for the NH and OH forms of the title compound. Calculated results reveal that the OH form is more stable than NH form. In addition, molecular electrostatic potential and NBO analysis of the title compound were performed at B3LYP/6-31G(d) level of theory.     

High-gain Al2O3:Nd3+ channel waveguide amplifiers at 880 nm, 1060 nm, and 1330 nm

Neodymium-doped aluminum oxide films with a range of Nd³⁺ concentrations are deposited on silicon wafers by reactive co-sputtering, and single-mode channel waveguides with various lengths are fabricated by reactive ion etching. Photoluminescence at 880, 1060, and 1330 nm from the Nd³⁺ ions with a lifetime of 325 μs is observed. Internal net gain at 845–945 nm, 1064, and 1330 nm is experimentally and theoretically investigated under continuous-wave excitation at 802 nm. Net optical gain of 6.3 dB/cm at 1064 nm and 1.93 dB/cm at 1330 nm is obtained in a 1.4-cm-long waveguide with a Nd³⁺ concentration of 1.68×10²⁰ cm^?3 when launching 45 mW of pump power. In longer waveguides a maximum gain of 14.4 dB and 5.1 dB is obtained at these wavelengths, respectively. Net optical gain is also observed in the range 865–930 nm and a peak gain of 1.57 dB/cm in a short and 3.0 dB in a 4.1-cm-long waveguide is obtained at 880 nm with a Nd³⁺ concentration of 0.65×10²⁰ cm^?3. By use of a rate-equation model, the gain on these three transitions is calculated, and the macroscopic parameter of energy-transfer upconversion as a function of Nd³⁺ concentration is derived. The high internal net gain indicates that Al₂O₃:Nd³⁺ channel waveguide amplifiers are suitable for providing gain in many integrated optical devices.     

Electrical,Film and Surface Properties of Water-Based Latexes Prepared by Semicontinuous Emulsion Polymerization

Summary: In this study, the results obtained with latexes prepared by semicontinuous emulsion polymerization with conventional anionic and nonionic emulsifiers and their different mixtures were presented. For this study, vinyl acetate-butyl acrylate latexes with a conventional anionic emulsifier (sodium lauril ether sulfate) and a nonionic emulsifier (30 mole nonyl phenol ethoxylate), of which films can be easily cast, were used. The latex properties in terms of mechanical stability, film-water absorption, and film-emulsifier exudation, and surface and electrical properties were assessed and compared.     

Dye’s theorem in the almost continuous category

Suppose X and Y are Polish spaces with non-atomic Borel probability measures μ and ν and suppose that T and S are ergodic measure-preserving homeomorphisms of (X, μ) and (Y, ν). Then there are invariant G _δ subsets X′ ⊂ X and Y′ ⊂ Y of full measure and a homeomorphism ϕ: X′ → Y′ which maps μ|X′ to ν|Y′ and maps T-orbits onto S-orbits. We also deal with the case where T and S preserve infinite invariant measures.     

EPR spectra of Cu2+ and VO2+ ions in ammonium hydrogen oxalate hemihydrate [(NH4)HC2O4 . (1/2)H2O] single crystals

Cu(2+) and VO(2+) doped ammonium hydrogen oxalate hemihydrate, [(NH(4))HC(2)O(4) . (1/2)H(2)O], single crystals have been studied at room temperature and at 113K in three mutually perpendicular planes. Both ions yield unexpectedly large number of lines. The calculated results of the Cu(2+) and VO(2+) doped in [(NH(4))HC(2)O(4) . (1/2)H(2)O] indicate that both ions substitute with the NH(4)(+) ion in the structure. The EPR spectra of Cu(2+) ions are characteristic of tetragonally elongated octahedral site and the spectra of VO(2+) are characteristic of tetragonally compressed complex. The angular variation of the EPR spectra has shown that two different Cu(2+) and VO(2+) complexes are located in different chemical environments, and each environment contains two magnetically inequivalent Cu(2+) and VO(2+) sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The principal g and the hyperfine (A) values of both ions are determined.     

Search for associated higgs boson production WH-->WWW*-->l+/-nul'+/-nu'+X in pp collisions at square root s=1.96 Te V

We present a search for associated Higgs boson production in the process pp-->WH-->WWW*-->l;+/-nul'+/-nu'+X in final states containing two like-sign isolated electrons or muons (e+/-e;+/-, e+/-micro+/-, or micro+/-micro+/-). The search is based on D0 run II data samples corresponding to integrated luminosities of 360-380 pb-1. No excess is observed over the predicted standard model background. We set 95% C.L. upper limits on sigma(pp-->WH)xBr(H-->WW*) between 3.2 and 2.8 pb for Higgs boson masses from 115 to 175 GeV.     

Manganese(III) acetate promoted acetoxylation of various α,β-unsaturated cyclopentanones

We describe the results of manganese(III) acetate based regioselective oxidation of various α,β-unsaturated cyclopentanones leading to α′-acetoxy α,β-unsaturated cyclopentanones in good yields. Products due to monophenyl and diphenyl substituted dimerization have been identified as byproducts of the reaction.     

Porosity and interior structure analysis of pellet-flocs

Pellet-flocs are the result of modified flocculation performance. They are spherically shaped and can reach several millimeters in size. Since pellet-floc aggregates are created from macroflocs and these from microflocs and these, in turn, from primary solid particles, it can be expected that the total porosity is composed of porosities resulting from spaces between all these sub-elements. Accordingly, micro- and macroporosity can be distinguished in the interior structure of pellet-flocs.

Although considerable attention has been given to total aggregate porosity measurement, no reports can be found about the full morphological characteristics of different types of pores. Moreover, there is no single reliable method that can accurately obtain values for the respective fractions of pore volume (microporosity, macroporosity) within a relatively big floc aggregate.

This work is an approach to probe the porosity within pellet-flocs at different size levels by combining the outcomes from different examination methods.

Pellet-floc aggregates were investigated using the following techniques: free settling, light microscopy of resin-embedded microtome slices and scanning electron microscopy (SEM).

The results confirmed that the biggest portion of porosity is composed of micropores in the size range of a few microns, which were first visible by SEM image analysis. Light microscopy of resin-embedded microtome slices is an accurate method to obtain so called macroporosity of a whole agglomerate with equivalent pore diameter above 50 μm. The study of free settling data revealed satisfactorily the total porosity of pellet-flocs. Finally, a multilevel porosity model of pellet-flocs could be obtained.     

Influences of Electrolytes, Polymers and a Surfactant on Rheological Properties of Bentonite–Water Systems

Characteristic rheological properties, such as viscosity, shear stress, yield point, gel strength and thixotropy, of natural Ca- bentonite and Na-peptized bentonite were studied after adding LiCl, KCl, CaCl2, MgCl2·6H2O electrolytes; (NaPO3)n, polyvinyl pyrolidone (PVP) polymers and an anionic surfactant (linear alkyl benzene sulphonate, LABS). Changes in flow properties under the influence of various additives at different quantities were investigated in these slurries. The experimental results are discussed in terms of bentonite forms, types and concentrations of additives and influence of exchangeable cations. Bivalent and monovalent cations display entirely different rheological properties in two groups of muds. Furthermore, the difference in the degree of activity of PVP polymer on the viscosity of two mud systems depend on the clay mineral structure. The slurry prepared with Na-bentonite contains a minimum number of tactoids and a maximum number of sheet-bearing clay particles, which reduces the surface area of the clay minerals and increases viscosity by adding PVP polymer.     

Simultaneous Determination of Anthocyanin and Ponceau 4R in Drink Powders by Derivative Spectrophotometry and Partial Least-Squares Multivariate Spectrophotometric Calibration

 Two methods for the simultaneous determination of anthocyanin and ponceau 4R in drink powders by second derivative spectrophotometry and by partial least-squares multivariate spectrophotometric calibration are described. The procedures do not require any separation step. The methods were applied to determine both colorants in commercial gelatin powders; the results obtained are compared.