The transverse ferromagnet spin-1 Ising model of alternating magnetic superlattice

Within the framework of the effective field theory with a probability distribution technique that accounts for the single-site spin correlations, we examine the critical behavior of the transverse ferromagnetic spin-1 Ising model of an alternating magnetic superlattice. The critical temperature of the alternating magnetic superlattice has been studied as a function of the interlayer and intralayer exchange interactions and the strength of the transverse field and the thickness of the finite superlattice. Received 12 January 2000 and Received in final form 14 September 2000     

On a systematic approach for cracked rotating shaft study: breathing mechanism,dynamics and instability

Nonlinear Dynamics - We present a systematic approach to deal with the modelling and analysis of the cracked rotating shafts behaviour. We begin by revisiting the problem of modelling the breathing...     

Development of a Bacterial Enzyme-Based Biosensor for the Detection and Quantification of Selenate

An enzymatic biosensor has been developed for the determination of selenate (SeO₄²⁻), in which selenate reductase (SeR) is chemically attached to a gold disk electrode by lipoic acid N-hydroxysuccinimide ester as linker, allowing the catalytic reduction of the SeO₄²⁻ to SeO₃²⁻. Modification of the gold electrode was characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and electrochemistry. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) measurements were performed in different buffers for selenate determination. Under optimum conditions, the calibration curve was linear over the range 7.0–3900.0 μg L⁻¹ with limits of detection and quantification of 4.97 and 15.56 μg L⁻¹, respectively. The possible interference of the relevant oxyanions SO₄²⁻, NO₃⁻, NO₂⁻, PO₄³⁻ and AsO₄³⁻ in the determination of SeO₄²⁻ was studied. Finally, the proposed biosensor was used to determine SeO₄²⁻ with recovery between 95.2 and 102.4 % in different real water samples.     

Retracted: Effective and Green One‐Pot Multicomponent Synthesis of Novel Derivatives of 4H‐Pyrans in the Presence of Hexamethylenetetramine as Catalyst in Water Medium

Hexamethylenetetramine (HMTA) catalyzes synthesis of new polyfunctionalized 4H‐pyrans by reaction of aromatic aldehyde, malononitrile, and β‐keto esters via one‐pot three‐component procedure in water medium. Addition of reactants was performed by two methods led to achieve similar results. Using HMTA in catalytic amount not only represents the economic face of the reaction, but also due to the use of water, a green and safe reaction condition is organized. Thus, the current strategy provides the benefits of high productivity, convenient operation, and environmental friendliness. Structure of all products was proved by elemental analysis, IR, ¹H‐NMR, and ¹³C‐NMR spectroscopy.     

Approximate solutions of Dirac equation for Tietz and general Manning-Rosen potentials using SUSYQM

In this paper, we consider the relativistic Dirac equation with Tietz and general Manning-Rosen potential. By using appropriate approximation, we obtained the approximate analytical solutions of the Dirac equation for the combined potential via the supersymmetric quantum mechanics (SUSYQM). Within the framework of spin and pseudospin symmetry limits, we obtained the relativistic energy eigenvalus and the corresponding components of the wave functions for Tietz and Manning-Rosen potential using the SUSYQM. We have also reported some numerical results and figures to show the effect of the tensor interactions.     

Heteroaromatization with Sulfonamido Phenyl Ethanone,Part I: Synthesis of Novel Pyrrolo[2,3-D]Pyrimidine and Pyrrolo[3,2-E][1,2,4]Triazolo[1,5-C]Pyrimidine Derivatives Containing Dimethylsulfonamide Moiety

4-(5-Amino-4-cyano-1-p-tolyl-1H-pyrrol-3-yl)-N,N-dimethyl-benzenesulfonamide (4) was prepared and converted to several pyrrolo[2,3-d]pyrimidin-5-yl)-N,N-dimethyl-benzenesulfonamide derivatives (5,7,9, and 13). Cyclocondensation of 13 with different electrophilic carbon reagents afforded several 4-(N,N-dimethylaminosulfonylphenyl)]pyrrolo[3,2-e][1,2,4]triazolo[1,5-c]-pyrimidine derivatives (14–17,19, and 20); IR, ¹HNMR, and mass spectra of the newly synthesized compounds were recorded. Most of the obtained compounds were screened against Gram-positive and Gram-negative bacteria and fungi, for which some of these derivatives gave promising results.