Materials Literature
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Characteristics of porous structure of silica gel Si-60 (pristine and covered by different amounts of pyrocarbon prepared by pyrolysis of acenaphthene, acetylacetone, and glucose, then heated at 500 °C in air or hydrothermally treated (HTT) at 150 or 200 °C, and also heated at 500 °C) were analyzed by using TEM, 1 H N…
We present here a detailed Rietveld analysis of the structure of paraelectric and antiferroelectric phases of Sr 0.70 Ca 0.30 TiO 3 using powder XRD data. It is shown that the observed antiferroelectric superlattice reflections can be explained by doubling of the C o parameter of the orthorhombic paraelectric phase. T…
Results of a detailed dielectric study of phase transition in Sr 1- x Ca x TiO 3 in the composition range 0.18⩽ x ⩽0.40 are reported. It is shown that the temperatures T ' m and T '' m corresponding to the peaks in the real (ε'( T )) and imaginary (ε''( T )) parts of the dielectric constant, respectively, are not only…
This electron-density study on corundum (alpha-Al2O3) is part of the Multipole Refinement Project supported by the IUCr Commission on Charge, Spin and Momentum Densities. For this purpose, eight different data sets (two experimental and six theoretical) were chosen from which the electron density was derived by multip…
An empirical fitting procedure is applied to derive interatomic potential parameters for a model phase transition system, namely potassium tetrachlorozincate (K(2)ZnCl(4)). The derived potential is found to reliably model the known crystallographic structure for the ferroelectric and paraelectric phases of this compou…
Abstract An experimental procedure is presented to describe the PVT behavior of multiphase polymeric materials in a wide range of cooling rates. In particular, the procedure is applied to a typical multiphase industrial polymer, that is, an industrial polypropylene–ethylene‐propylene rubber (iPP–EPR) copolymer with a…
Abstract Rigid polyurethane foams (PUFs) were prepared from polymeric 4,4′‐diphenylmethane diisocyanate, polyester polyol, 1,4‐butane diol, silicone surfactant, hydrochlorofluorocarbon (HCFC) 141B, and distilled water. The properties and structure of the PUFs were investigated with differential scanning calorimetry (D…
It is generally assumed that decagonal quasicrystals show periodically arranged atomic layers only on net planes perpendicular to the tenfold axis and quasiperiodically arranged ones parallel to it. However, there also do exist only slightly puckered atomic layers that are periodically arranged and inclined to the ten…
Er-doped sodium-niobium phosphate glasses have been produced by the melting technique. Their optical properties have been fully characterized and show a broad fluorescence band around 1.5 micrometers . The fluorescence lifetime of the <SUP>4</SUP>I<SUB>13/2</SUB> metastable state is long enough to make these glasses s…
A diffuse layer of water-soluble polymer chemically grafted to the surface of a hydrophobic polymer colloid has been created by the second-stage polymerization of dimethylaminoethyl methacrylate (DMAEMA) onto the biomacromolecule polyisoprene in natural rubber latex and also onto synthetic polybutadiene and polystyren…
Magnetic properties of the quaternary oxides Ba 2 LnTaO 6 (Ln = Y or lanthanides) are reported. Their powder x-ray diffraction measurements and Rietveld analysis show that they have an ordered perovskite structure and are monoclinic (Ln = La-Tb) with space group P 2 1 / n or cubic (Ln = Y, Dy-Lu) with space group Fm m…
We report an experimental result for a lamellar orientation in cross-linked polystyrene- block -polybutadiene- block -polystyrene (SBS) triblock copolymer that was uniaxially drawn at 130 °C (above the glass transition temperature of polystyrene; T g( PS) ). The lamellar orientation was examined using two-dimensional…
The molecular structure of a series of hyperbranched polyesteramides was studied using size exclusion chromatography (SEC), mass spectrometry (MS) and small-angle neutron scattering (SANS). Products with increasing molecular mass were obtained through the polycondensation of in situ produced AB 2 -like monomeric units…
Abstract Recently, as a result of developments in nanotechniques, there has been a growing interest in the field of nanocomposites. The use of inorganic nanoparticle‐filled composites can provide high‐performance materials that find applications in several industrial fields. In the present work, preliminary studies co…
PhSb(dmit) (dmit(2)(-), 4,5-dithiolato-1,3-dithiole-2-thione), the first neutral organo-antimony dithiolene complex, has been synthesized by addition of PhSbCl(2) on a suspension of Na(2)(dmit). The complex was characterized by spectroscopic ((1)H and (13)C NMR and IR) methods and elemental analysis. Its crystal struc…
Abstract Montmorillonite minerals were modified in two distinct steps in order to remove hydroxlated toxicants from the aqueous environment. At first, the montmorillonite minerals were acrylated with the silylating agent γ‐methcaryloxypropyl trimethoxysilane to give a product denoted as TAY‐10. In the second step thes…
In connection with our chemotaxonomic studies of Malaysian species of the red algal genus Laurencia, the chemical composition of Laurencia pannosa Zanardini was examined. Two halogenated sesquiterpenoids, named pannosanol (1) and pannosane (2), have been isolated along with a halogenated C15-acetogenin, (3Z)-chlorofuc…
We report the results of resistivity (ρ), magnetoresistance (MR) and in-field heat capacity ( C ) measurements on TmCu and TmAg compounds. Despite the different nature of magnetic transitions - first-order in TmCu and second-order in TmAg - the magnetocaloric effect (MCE) obtained from in-field heat capacity data is s…
The syntheses, crystal and electronic structures, and linear optical properties of the new orthoborates LiMBO 3 (M = Sr, Ba) are reported here. These compounds, which crystallize in the monoclinic space group P 2 1 / n with cell dimensions a = 6.476(2), b = 6.684(3), c = 6.843(3) Å, β = 109.41(3)°, and Z = 4 for M = S…
Two new bis(ether anhydride)s, 2,2‘-dimethyl-4,4‘-bis[4-(3,4-dicarboxyphenoxy)]biphenyl dianhydride ( 4A ) and bis[4-(3,4-dicarboxy phenoxy)phenyl]diphenylmethane dianhydride ( 4B ), were prepared in three steps starting from nitrodisplacement of 4-nitrophthalonitrile with 2,2‘-dimethylbiphenyl-4,4‘-diol and bis(4-hyd…