Materials Literature
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Abstract Binuclear iron(III) spin-crossover complex [Fe2(salten)2(az)](BPh4)2 (az = azobis(4-pyridine)) was synthesized and characterized by X-ray single-crystal diffraction, Mössbauer spectra, magnetic susceptibilities and electronic spectra. This complex contains the ligand which is able to photoisomerize as a bridg…
We report measurements of Raman spectra and infrared-absorption spectra of hexagonal ${\mathrm{BaMnO}}_{3}$ in its polycrystalline form. The results are discussed in the framework of a group-theoretical analysis of the allowed zero-wave-vector phonons in this compound. The temperature dependence of the frequency and l…
Block copolymers of unsubstituted poly(p-xylylene)(PPX) and Ge- or Sn-organic bridged PPX (GePPX and SnPPX) were prepared by pyrolysis of specially synthesized organometallic p-cyclophane precursors followed by deposition and polymerization of the thus produced p-xylylene monomers. The copolymer structure and thermal…
X-ray diffraction based on the comparison of experimental and calculated powder profiles enabled the determination of the structural characteristics of hydrated and dehydrated Tunisian nacrite. Using the concept describing the structure of natural nacrite, the stacking mode of the layers in the hydrated and dehydrated…
Organophosphazenes with a similar mesogenic moiety were prepared and their mesogenicity was studied by differential scanning calorinetry (DSC) measurements and polarizing microsope observations. In cyclotriphosphazenes with alk-oxybiphenyl and Schiff base moieties, mesomorphic phase transitions were observed, but no…
We report on the results of optical, X-ray and NMR studies of light-induced phenomena in smectic phases triggered by molecular phototransformations. UV irradiation causes trans-to-cis isomerization of the dopant molecules while irradiation in the visible part of the spectrum facilitates cis-to-trans relaxation. Cis-to…
New pentacyano complexes of tri- and tetravalent platinum were obtained in aqueous solution and characterized by multinuclear NMR ((195)Pt, (13)C) supported by Raman spectroscopy. The complexes form as products of redox decomposition of metal-metal bonded platinum-thallium compounds. The trimetallic [(NC)(5)Pt-Tl-Pt(C…
Abstract The populations of four aliphatic polyester-degrading microorganisms at 50 °C were demonstrated in vitro. The percentage of degraders to total microorganisms were: 5-86%, PHB; 3-49%, PCL; 0-87.5%, PBS; and 0-4.5%, PLA.
An overview of contemporary methods of crystal structure solution from powder diffraction data is given.Methods are compared with respect to their advantages and disadvantages.A choice of an appropriate method is discussed in the light of understanding the structural problem to be solved.The need of the variety of met…
Transparent and crack-free SrTiO3 thin films were prepared on fused silica substrates by a sol–gel technique. Strontium acetate and titanium tetra-n-butoxide were used as starting materials. The structural properties of the thin films were studied by X-ray diffraction. The films annealed at 700 °C have good crystallin…
We study the use of shape memory alloys for the purpose of passive vibration damping in a one degree of freedom oscillator. We assume that the pseudoelastic behavior of the shape memory material is due to a stress-induced phase transformation which is governed by a kinetic relation. We consider both impulsively initia…
Structure of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fibers prepared by drawing and annealing processes has been analyzed through wide-angle X-ray diffraction (WAXD), density, infrared dichroism, and birefringence measurements. There are three different types of crystalline structure in these fibers: two of these…
Zone-center TO phonon frequencies and eigenvectors of cubic ${\mathrm{SrHfO}}_{3}$ are determinated, by calculating atomic forces, in the framework of the local density approximation to density functional theory to sense the presence of possible lattice instabilities. The results are compared with parallel calculation…
SmFe 2 crystals were grown by the self-flux method using Sm as a flux, and the crystallographic and magnetic properties of the crystal were studied for the first time. SmFe 2 crystallizes in a cubic MgCu 2 -type structure (space group of Fd3m ) with lattice constants of a =0.7425 nm. Saturation magnetization M S at 5…
By taking into account the effects of domain structures and X-ray absorption, the superstructure of PbZrO 3 , lead zirconate, has been determined at room temperature. The space group is Pbam with a unit cell of a = 5.8884 (19), b = 11.771 (4) and c = 8.226 (3) Å, with Z = 8. The intensity data were collected using sho…
It has been demonstrated that Fourier transform infrared (FT-IR) microspectroscopy can be used to study different types of spherulites of poly(vinylidene fluoride) formed by different crystal modifications. Because of selective IR bands of the α and the γ modification, respectively, it is possible to map the crystalli…
The hydrolysis behaviour of lactic acid based poly(ester-urethane)s has been studied in a buffer solution of pH 7·00 at 37 and 55°C. Samples were prepared using a straight two step lactic acid polymerization process. The lactic acid was first polymerized by condensation with a low molecular weight by hydroxyl terminat…
Abstract The microtextural changes in the kaolinization of primary phyllosilicates including biotite, sericite, clinochlore and muscovite were investigated by scanning electron microscopy (SEM) and microchemical analysis of thin sections of weathered anorthosite. Kaolinization began at grain edges and propagated towar…
L'inhibition de la corrosion de l'alliage Cu-Zn (70/30) en milieu H2SO4 0.1 M par des composés organiques de type “tétrazole" a été étudiée en utilisant les méthodes gravimétrique et électrochimique. Les résultats obtenus montrent que le 1-phényl-5-mercapto-1,2,3,4-tétrazole (PMT) est le meilleur inhibiteur de la séri…
The process of phase separation for quenched, three-dimensional binary alloy systems with coupled elastic fields was investigated with Langevin simulations. The elastic effects are the result of a dilational misfit introduced via inhomogeneities in the elastic constants of the system. A selection criterion for the sha…