Ball milling synthesis and stability under pressure in nanostructured HITPERM alloys

The main aim of the present work is to study the synthesis and stability of soft-magnetic nanostructured materials under high pressure-high temperature conditions. HITPERM alloy powders were prepared by high-energy ball-milling. The as-milled alloys consist of an iron-based nanocrystalline solid solution. The evolution of crystallinity and grain-size during the ball-milling process and investigations under external pressure up to 3 GPa for temperatures up to 1200 °C were evaluated using synchrotron radiation X-ray diffraction.     

Adsorption of I2 by Macrocyclic Polyazadithiophenolato Complexes Mediated by Charge‐Transfer Interactions

The macrocyclic complex [Ni₂(L)(OAc)]ClO₄ ( 1 ) adsorbs up to 17 molar equivalents (>270 wt %) of iodine, although it does not exhibit permanent porosity. Vibrational spectroscopic and crystallographic studies reveal that two I₂ molecules are captured by means of thiophenolate→I₂ charge‐transfer interactions, which enable the diffusion and sorption of further I₂ molecules in a polyiodide‐like network. The efficient sorption and desorption characteristics make this material suitable for accommodation, sensing, and slow release of I₂.     

Analytical approximate solutions to the Thomas-Fermi equation

The purpose of this paper is to show how to use the Optimal Homotopy Asymptotic Method (OHAM) to solve the nonlinear differential Thomas-Fermi equation. Our procedure does not depend upon small parameters and provides us with a convenient way to optimally control the convergence of the approximate solutions. An excellent agreement was found between our approximate results and numerical solutions, which prove that OHAM is very efficient in practice, ensuring a very rapid convergence after only one iteration.     

A High-Field EPR Study of the Accelerated Dynamics of the Amorphous Fraction of Semicrystalline Poly(dimethylsiloxane) at the Melting Point

The reorientation of a small paramagnetic tracer in poly(dimethylsiloxane) (PDMS) has been investigated by high-field electron paramagnetic resonance spectroscopy at a Larmor frequency of 285 GHz. The tracer is confined in the disordered phase of the semicrystalline PDMS. A sudden change of the rotational dynamics is observed close to the melting point (213 K) of the crystallites. This points to strong coupling between the crystalline and the disordered fractions of PDMS. Below the glass transition ( \(T_\mathrm{g} \sim 150 \mathrm{K}\) ), the tracer reorientation occurs via small angle jumps, with no apparent distribution of the correlation times. Above \(T_\mathrm{g}\) , a power-law distribution of correlation times is evidenced.     

Supermode resonances in a multi-core holey fiber-based sensor

We report experimental research of the laser-produced indium plasma in hydrogen, argon and residual atmospheric ambient conditions. Note on general plasma behavior and morphology is presented. On the basis of intensity ratio of the two intense neutral resonance spectral lines (In I 410.2 nm and 451.1 nm), self-absorption was found to be almost negligible in case of argon environment at a pressure of 6650 Pa. Under these conditions, the first Stark widths (W) and shifts (d) measurements were performed as well. The resulting synthetic Lorentz profiles, based on the hyperfine structure of these two lines and corresponded W values, were calculated in order to reproduce measured W _m in case of particular electron temperature (T) and number density (N). These results should be of interest to the upcoming theoretical calculations concerning neutral indium spectral lines and also for various diagnostic applications.     

Hybrid polymeric latexes containing magnetite

The work describes a study for preparing polystyrene (PSt) and polymethyl methacrylate (PMMA) latex, containing magnetite (Fe₃O₄), covalently bounded to the polymeric chains. The magnetite was functionalized with various alkoxysilanes containing double bonds: vinyltriethoxysilane (VTES), methacryloyl propyl trimethoxysilane (MPTS) and vinyldimethylethoxysilane (VMe₂TES). The ferrite-silane composite forms higher average size particles with MPTS than with VTES. Ferrite functionalized with VMe₂TES forms stable latexes with both PSt and PMMA polymers. PSt forms also stable latexes with ferrite functionalized with VTES but unstable with ferrite functionalized with MPTS.     

Thermal study of new biologic active complexes with mixed ligands

Five new coordinative compounds that contain mixed ligands (4,4′-bipyridine and methacrylate anion) were synthesized and characterized (elemental analysis, IR and UV–Vis spectroscopy, and thermal studies). The complexes are of the type [M(4,4′-bipy)(C₄H₅O₂)₂]·nH₂O ((1) M:Mn, n = 0; (2) Co, n = 0.5; (3) M:Ni, n = 1.5; (4) M:Cu, n = 0.5; (5) M:Zn, n = 0.5; 4,4′-bipy: 4,4′-bipyridine; C₄H₅O₂: methacrylate anion). All the tested complexes exhibited very low MIC values against Escherichia coli strains and one compound against Staphylococcus aureus. Besides the specific antimicrobial spectrum, these compounds also inhibited the microbial ability to colonize the inert surfaces, acting as potential anti-adherence and biofilm-controlling agents. The thermal behavior provided confirmation of the complexes' compositions as well as the number and the nature of water molecules and the intervals of thermal stability.     

Synthesis of new 10,11-dihydrodibenzo[a,d]cycloheptene S-thiocarbamate derivatives via a benzylic Newman–Kwart rearrangement

New S-thiocarbamates possessing a 10,11-dihydro-5H-dibenzo[a,d]cycloheptene moiety were obtained unexpectedly in the process of preparing new O-thiocarbamates starting from 5-dibenzosuberol (10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-ol) and aroyl-isothiocyanates. These compounds were obtained via a benzylic Newman–Kwart rearrangement mechanism. The structures of the new thiocarbamates were confirmed by elemental analysis, IR, and NMR spectroscopy and by X-ray crystallography.     

An optimal iteration method with application to the Thomas-Fermi equation

The aim of this paper is to introduce a new approximate method, namely the Optimal Parametric Iteration Method (OPIM) to provide an analytical approximate solution to Thomas-Fermi equation. This new iteration approach provides us with a convenient way to optimally control the convergence of the approximate solution. A good agreement between the obtained solution and some well-known results has been demonstrated. The proposed technique can be easily applied to handle other strongly nonlinear problems.     

Structural and thermoluminescence properties of undoped and Fe-doped-TiO<Subscript>2</Subscript> nanopowders processed by sol–gel method

In this study, we report on the nanocrystalline powders of TiO₂ and Fe-doped TiO₂ (anatase and rutile phases) prepared by sol–gel method. The X-ray diffraction and Raman spectroscopy measurements indicated the presence of anatase or rutile phase in nanopowders. TEM micrographs showed 10 and 112 nm average particle sizes for anatase and rutile, respectively. Furthermore, their thermoluminescence properties were analyzed.