Phase transition at a nanometer scale detected by acoustic emission within the cubic phase Pb(Zn1/3Nb2/3)O3-xPbTiO3 relaxor ferroelectrics

Pb(Zn(1/3)Nb(2/3))O3-xPbTiO(3) (x=4.5%-12%) relaxor ferroelectric crystals have been studied by means of acoustic emission (AE) in the 400-540 K temperature range. An anomalous AE activity independent of the ground state relaxor/morphotropic/ferroelectric crossover has been revealed at around 500 K, and it is associated with the "waterfall" feature related to the existence of polar nanoregions (PNRs). The 500 K AE anomaly is attributed to local martensitelike cubic-to-tetragonal ferroelectric transitions within the PNRs imbedded in a nonpolar (cubic) matrix.     

Adsorption,Thermodynamic, and Experimental Studies of Corrosion Inhibitor of Tin in 0.2 M Maleic Acid by Hydrogen Phosphate Ions (HPO42−)

The inhibition efficiency of H₂PO₄²⁻ ions against tin corrosion in 0.2 M maleic acid is studied using electrochemical methods, surface analytical methods, and thermodynamic analysis. The potentiodynamic polarization plots showed the presence of an active/passive transition state of the tin electrode. The EIS measurements confirmed that the inhibition efficiency of H₂PO₄²⁻ increased by increasing the concentration (η=81 % at C_inh=2.10⁻² M) and decreased by rising the temperature. The polarization tests demonstrated that the inhibitor performs as a cathodic-type. The adsorption of the inhibitor was spontaneous and followed the Langmuir adsorption isotherm. A model of the inhibition mechanism was suggested.     

Syntheses of novel 1,5-benzodiazepine derivatives: Crystal structures,spectroscopic characterizations,Hirshfeld surface analyses,molecular docking studies,DFT calculations,corrosion inhibition anticipation,and antibacterial activities

A series of newly pyrazolo-1,5-benzodiazepine derivatives ( 5 - 7 ) was performed and characterized by using ¹H, ¹³C-NMR spectroscopic measurements. The molecular and crystal structures of two compounds 2 and 7 have also been further examined by single-crystal X-ray crystallography showing that the alkyl groups are beard by sulfur atom and to pyrazolic nitrogen atom in position 2 and not in position 1 of the tricyclic compounds as described in the literature. In addition, through Hirshfeld surface analysis, molecular docking studies, and DFT calculations, the closest contact between the active atoms of the compound can be determined. Also, the Monte Carlo simulations outcomes show that compounds 2 and 7 can be considered as a good acidic corrosion inhibitor for the aluminum metal, while emphasizing that the compound 7 provides enhanced prevention. Finally, compounds 1 to 7 were evaluated for their antibacterial activity against Gram-positive and Gram-negative microbial strains such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus. The results obtained demonstrated the antibacterial activity of compounds 1 to 7 tested using the minimal inhibitory concentration.     

Encapsulation effect of π-conjugated quaterthiophene on the radial breathing and tangential modes of semiconducting and metallic single-walled carbon nanotubes

We developed a hybrid approach, combining the density functional theory, molecular mechanics, bond polarizability model and the spectral moment's method to compute the nonresonant Raman spectra of a single quaterthiophene (4T) molecule encapsulated into a single-walled carbon nanotube (metallic or semiconducting). We reported the optimal tube diameter allowing the 4T encapsulation. The influence of the encapsulation on the Raman modes of the 4T molecule and those of the nanotube (radial breathing modes and tangential modes) are analyzed. An eventual charge transfer between the 4T oligomer and the nanotube is discussed.     

Mesoporous pyrophyllite–titania nanocomposites: synthesis and activity in phenol photocatalytic degradation

Research on Chemical Intermediates - Pyrophyllite–TiO2 nanocomposite PTi750 was successfully synthesized using a sol–gel method at ambient temperature based on exfoliation of the...     

Finite dimensional global attractor for a dissipative anisotropic fourth order Schrödinger equation

We study the long-time behavior of the solutions to a nonlinear damped anisotropic fourth order Schrödinger type equation in ${\mathbb{R}}^2$. We prove that this behavior is described by the existence of regular finite-dimensional global attractor in the energy space.     

Stereoselective synthesis of functional dehydrophenylalanine derivatives from novel β‐chloroamino esters

New functional dehydrophenylalanines 3 were prepared from β‐amino alcohols 1 in a two‐step reaction sequence. The synthesis involved chlorination of the starting amino alcohols 1 to afford the intermediate erythro β‐chloroamines 2 . Treatment of the latter with an appropriate base led to a highly stereoselective elimination reaction, giving the corresponding (E)‐dehydrophenylalanine derivatives 3 in high yields. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 23:91–98, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20756