Materials Literature
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Systematic dc and ac magnetic susceptibility studies have been performed on single-phase ${\mathrm{LaCoO}}_{3}$ powder samples. Evidence is presented in support of the existence of ferromagnetic (FM1, FM2) and antiferromagnetic (AFM) interactions at low temperatures. FM1 and FM2 are ferromagnetic interactions that occ…
The formation of the sitting-atop (SAT) complexes of 5,10,15,20-tetraphenylporphyrin (H(2)tpp), 5,10,15,20-tetrakis(4-chlorophenyl)porphyrin (H(2)t(4-Clp)p), 5,10,15,20-tetramesitylporphyrin (H(2)tmp), and 2,3,7,8,12,13,17,18-octaethylporphyrin (H(2)oep) with the Cu(II) ion was spectrophotometrically confirmed in aque…
In this paper we present a review of the recent inelastic x-ray scattering (IXS) studies on the high-frequency collective dynamics in topologically disordered systems. At mesoscopic exchanged momenta ( Q ≈1-10 nm -1 ), these IXS studies allowed experimental demonstration of the existence in glasses of propagating acou…
The alternating-current (ac) conductivity σ(ω) and the dielectric permittivity of polyaniline doped with β-naphthalene sulphonic acid (NSA) have been extensively studied in the temperature range of 300 K to 80 K and in the frequency range of 500 Hz to 10 MHz. The ac conductivity follows a power law in frequency, σ(ω)∝…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSynthesis and Characterization of a 2,1,3-Benzothiadiazole-b-alkyne-b-1,4- bis(2-ethylhexyloxy)benzene Terpolymer, a Stable Low-Band-Gap Poly(heteroaryleneethynylene)Carlito G. Bangcuyo, Una Evans, Michael L. Myrick, and Uwe H. F. B…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFunctionalization of [MoW5O19]2- with Aromatic Amines: Synthesis of the First Arylimido Derivatives of Mixed-Metal PolyoxometalatesYongge Wei, Meng Lu, Calida Fung-chi Cheung, Charles L. Barnes, and Zhonghua PengView Author Information Departments of Chemistry, Univers…
A mechanism to enhance hardness in multilayer coatings is proposed. Using the technologically important hard transition metal carbides as prototypes, although the principle is transferable also to other systems, we demonstrate, from first-principles calculations, that by suitable alloying the energy difference between…
In this paper the influence of UV irradiation on the luminescence quantum efficiency of nanocrystalline ZnS:Mn 2+ is studied. Samples passivated with poly(vinylbutyral) (PVB), poly(vinyl alcohol) (PVA), methacrylic acid (MA), and sodium polyphosphate (PP) and samples without passivating polymer were UV irradiated in a…
A platinum electrode was coated with polyelectrolyte multilayer (PEM) films to prepare an amperometric hydrogen peroxide sensor which can be used in the presence of possible interferences such as ascorbic acid, uric acid, and acetaminophen. The PEM films were prepared on the surface of a Pt disk electrode by an altern…
Highly concentrated CdS colloids (about 30 wt %) are prepared in acetone through the grafting of 4-fluorophenylthiol at their surface. 19 F NMR measurements show that the controlled oxidation by an aqueous solution of hydrogen peroxide leads to a mixture of dithiol and fluorosulfonate species. Aggregation of particles…
Multiarm star polymers, consisting of a high number of linear homopolymer arms joined covalently to a central core, represent model soft ‘hybrid’ spheres encompassing both polymeric (arm) and colloidal (core) character. Due to this topology, the single star has a nonuniform monomer density distribution. In nondilute s…
High-temperature electrical property measurements (electrical conductivity, thermoelectric coefficient) on polycrystalline ${\mathrm{CuAlO}}_{2}$ exhibited characteristic small polaron features, i.e., low mobilities (0.1--0.4 ${\mathrm{cm}}^{2}$/V s) and an activation energy of \ensuremath{\sim}0.14 eV. The thermopowe…
The luminescence quantum efficiency of nanocrystalline ZnS:Mn 2+ is studied to provide a better understanding on how the quantum efficiency is influenced by the Mn 2+ concentration, the nature of the passivating polymer, and the synthesis conditions. The results show an increase of the luminescence quantum efficiency…
Within the framework of the mode-coupling theory of super-cooled liquids, we investigate new phenomena in colloidal systems on approach to their glass transitions. When the inter-particle potential contains an attractive part, besides the usual repulsive hard core, two intersecting liquid-glass transition lines appear…
In this review we address some of the experimental challenges found in the x-ray diffraction characterization of the low-symmetry phases recently discovered in the PZT, PZN-PT and PMN-PT piezoelectric systems around their morphotropic phase boundaries. In particular, we discuss the need for special care in the prepara…
A natural ferromagnesian cordierite which had been annealed at 1355°C has been found, by TEM, to contain submicroscopic cross hatched modulated microstructures (tweed) localised near Al2O3 inclusions, while most of the sample, apart from some melting features, remained homogeneous and orthorhombic in symmetry. SAED pa…
The dispersion of sesquioxide-rich or plinthitic soils is difficult and not completely achieved within routine dispersion period. Two prolonged shaking periods of 24 and 48 hours were tested to see which gives a more complete dispersion of two plinthtic soils—a drier Plinthustalf and a more humid Plinthustult. Iron ox…
The change in the order−disorder transition temperature ( T ODT ) of a diblock copolymer, induced by the addition of a random copolymer, was investigated with synchrotron small-angle X-ray scattering and differential scanning calorimetry techniques. The studied block copolymer was poly(styrene- b -butadiene) containin…
The phase diagram of the two-component system 2-methyl-2-chloropropane ((CH 3 ) 3 CCl) and 1,1,1-trichloroethane ((CH 3 )CCl 3 ) has been determined by means of X-ray powder diffraction and thermal analysis techniques from 180 K to the liquid state. The isomorphism relationship between the stable orientationally disor…
A variety of alkoxythiophenes have been synthesized that represent ideal subunits for the synthesis of a new class of thermotropic liquid crystals via palladium-catalyzed cross-coupling reactions and organometallic derivatization. The methodology used represents the first highly efficient synthesis of alkoxythiophenes…