Renormalization of the Higgs model: Minimizers,propagators and the stability of mean field theory

We study the effective actionsS ^(k) obtained byk iterations of a renormalization transformation of the U(1) Higgs model ind=2 or 3 spacetime dimensions. We identify a quadratic approximationS _Q ^(k) toS ^(k) which we call mean field theory, and which will serve as the starting point for a convergent expansion of the Green's functions, uniformly in the lattice spacing. Here we show how the approximationsS _Q ^(k) arise and how to handle gauge fixing, necessary for the analysis of the continuum limit. We also establish stability bounds onS _Q ^(k) , uniformly ink. This is an essential step toward proving the existence of a gap in the mass spectrum and exponential decay of gauge invariant correlations.Dedicated to the memory of Kurt SymanzikSupported in part by the National Science Foundation under Grant PHY 82-03669     

Generalized Pöschl-teller potential

From the point of view of the theory of differential equations, we present a four-parameter exactly solvable generalized Pöschl-Teller potential, related to the Jacobi polynomials, using the previously unconsidered equations.     

Space-time compactification induced by nonlinear sigma models,gauge fields and submersions

The nonlinear sigma model coupled to gravity in (4+K) dimensions is used to trigger the compactification of space-time. A very general class of solutions is given by submersions from the extradimensional space onto the space in which the scalar fields take values. The existence of some vertical Killing vectors on the extra space can produce massless gauge bosons.Presented at the International Conference Selected Topics in Quantum Field Theory and Mathematical Physics, Bechyn, Czechoslovakia, June 23–27, 1986.     

Adsorption of Brilliant Yellow onto Sepiolite: Evaluation of Thermodynamics and Kinetics and the Application of Nonlinear Isotherm Models

We studied the adsorption of Brilliant Yellow (BY) from aqueous solutions onto sepiolite and determined the adsorption equilibrium isotherms. We applied pseudo-first-order and pseudo-second-order kinetic models; the adsorption of BY onto sepiolite was best described by the pseudo-second-order kinetic model. The experimental data obtained at different temperatures were analyzed using various isotherm models; the Koble–Corrigan isotherm model provided the best fits for the BY adsorption data at all temperatures. The thermodynamic parameters of the BY adsorption onto sepiolite indicated that the adsorption process is spontaneous and exothermic in nature.     

Synthesis and characterization of tetra-armed-thiosemicarbazone and its salen/salophen capped transition metal complexes: Investigation of their thermal and magnetic properties

In this work, we aimed to synthesize and characterize a novel tetra-directional ligand, (2E,2′E)-2,2′-((((2-(1,3-bis(4-((E)-(2-carbamothioylhydrazono)methyl)phenoxy)propan-2-ylidene)propane-1,3-diyl)bis(oxy))bis(4,1-phenylene))bis(methanylylidene))bis(hydrazinecarbothioamide) (5), including thiosemicarbazone group and its novel tetra-directional-tetra-nuclear Schiff base complexes. For this purpose, we used 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene (2) as starting material. 4,4′-((2-(1,3-Bis(4-formylphenoxy)propan-2-ylidene)propane-1,3-diyl) bis(oxy))dibenzaldehyde (3) was synthesized by the reaction of an equivalent 1,4-dibromo-2,3-bis(bromomethyl)but-2-ene (2) and 4 equivalents of 4-hydroxybenzaldehyde. Then, compound 5 was synthesized in high yield (86%) by a condensation reaction of compound 3 with thiosemicarbazide (4). Finally, four novel tetra-nuclear Cr(III) or Fe(III) complexes of compound 5 were synthesized. The synthesized compounds were characterized using elemental analyses, ¹H NMR, Fourier transform–infrared spectrometry, liquid chromatography–mass spectrometry (ESI⁺), and thermal analyses. The metal ratios of the prepared complexes were determined using an atomic absorption spectrophotometer. We also investigated their effects on the magnetic behaviors of [salen, salophen, Cr(III)/Fe(III)] capped complexes. The complexes were found to be low-spin distorted octahedral Fe(III) and distorted octahedral Cr(III), all bridged by thiosemicarbazone.     

CVD grown 2D MoS2 layers: A photoluminescence and fluorescence lifetime imaging study

In this letter, we report on the fluorescence lifetime imaging and accompanying photoluminescence properties of a chemical vapour deposition (CVD) grown atomically thin material, MoS₂. µ‐Raman, µ‐photoluminescence (PL) and fluorescence lifetime imaging microscopy (FLIM) are utilized to probe the fluorescence lifetime and photoluminescence properties of individual flakes of MoS₂ films. Usage of these three techniques allows identification of the grown layers, grain boundaries, structural defects and their relative effects on the PL and fluorescence lifetime spectra. Our investigation on individual monolayer flakes reveals a clear increase of the fluorescence lifetime from 0.3 ns to 0.45 ns at the edges with respect to interior region. On the other hand, investigation of the film layer reveals quenching of PL intensity and lifetime at the grain boundaries. These results could be important for applications where the activity of edges is important such as in photocatalytic water splitting. Finally, it has been demonstrated that PL mapping and FLIM are viable techniques for the investigation of the grain‐boundaries.

     

Electron spectroscopic investigations of CdS and CdTe electrochemically coated on glass

The electrodeposition of CdS and CdTe is investigated to improve the stoichiometric properties of CdS/CdTe layers on ITO-glass substrates for solar cell applications. X-ray photoelectron spectroscopy is utilized for the characterization of the CdS and CdTe layers. The influence of the electrodeposition potential, the pH and the thiosulfate concentration on the stoichiometry of CdS and CdTe layers are discussed.     

Synthesis and antitumor activity of new silver(I)-N-heterocyclic carbene complexes

Abstract

In this study, two novel benzimidazole-based N-heterocyclic carbene ligands (1a-b) and their silver(I) complexes (2a-b) were synthesized. All new compounds were characterized by FT-IR, LC-MS, ¹H NMR, and ¹³C NMR spectroscopies. The in vitro antitumor activities of NHC ligands (1a-b) and their silver(I) complexes (2a-b) against DU-145 human prostate cancer cells, MDA-MB-231 and MCF-7 human breast cancer cells and L-929 (normal cells adipose from mouse) were also determined using MTT analysis for 24?h, 48?h, and 72?h. The results showed that while NHC ligands did not have in vitro antitumor activity on MCF-7, MDA-MB-231 and DU-145 cells, Ag(I)-NHC complexes have in vitro antitumor activities. The in vitro antitumor activity of 2a was found to be lower than that of 2b. Ag(I)-NHC complexes were observed to have higher IC₅₀ values for non-cancerous cell lines than cancer cells.     

UO2 2+, Tl+, Pb2+, Ra2+, Bi3+ and Ac3+ adsorption onto polyacrylamide-zeolite composite and its modified composition by phytic acid

The adsorption of naturally occurring radionuclides (UO₂ ²⁺, Tl⁺, Pb²⁺, Ra²⁺, Bi³⁺ and Ac³⁺) onto zeolite (Z) and polyacrylamide-zeolite composite (PAA-Z) and its modified composition by phytic acid (Z-Phy and PAA-Z-Phy) were investigated. Adsorption parameters were derived from the Langmuir and Freundlich fits to adsorption isotherms of the ions studied. The adsorption isotherms were of L and H types. The adsorption capacity of Z decreased by PAA inclusion, but the Phy modification of PAA-Z increased the capacity back to that of Z. The Phy modification made the adsorption spontaneity at least ten times better than in the absence of Phy. This investigation showed that the zeolite, as one of the most abundant natural materials and commonly used adsorbent can also be used for the removal of UO₂ ²⁺ and, in the PAA-Z form, of the studied radionuclides. The usage of Z, as PAA-Z and its Phy modification provide research materials which possess adequate practicality and effectiveness in studies of adsorption. This revised version was published online in July 2006 with corrections to the Cover Date.