Materials Literature
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The first achiral bent core banana-shaped mesogen consisting of a thermally and hydrolytically stable salicylaldimine (2-hydroxybenzylideneamine) mesogenic segment has been synthesized and evaluated for its liquid crystalline behavior. This novel compound exhibits a single switchable mesophase over 60 °C temperature r…
Thin films of polycarbosilane were deposited on Si and SiO 2 substrates. Instead of conventional oven annealing (high temperatures, inert atmosphere), laser pyrolysis was used to achieve the polymer‐to‐ceramic conversion. In some conditions, especially when laser radiation absorption was enhanced by depositing a carbo…
Monomeric iridium(II) porphyrin complexes of tetrakis(2,4,6-trialkylphenyl)porphyrin ligands that are generated by photolysis of the Ir–Me derivatives are found to have the dxy2 dz22 dxz,yz3 ground electron configuration which differs from the dxy2 dxz,yz4 dz21 configuration observed for the Co(II) and Rh(II) analogs;…
In order to clarify the mechanism of remarkable creep strength of the 9Cr–2W–0.2V–Ta steels, high-Cr heat-resistant steels with Mo replaced by W and Nb by Ta for reducing induced radioactivity, the microstructural evolution during creep tests has been studied and compared with that in conventional 9Cr–1Mo–0.2V–Nb stee…
The experimentally postulated mechanism for the interconversion between (S)-vinylglycolate and (R)-vinylglycolate catalyzed by mandelate racemase enzyme consists of a two-step quite symmetric process through a dianionic enolic intermediate that is formed after the abstraction of the alpha-proton of vinylglycolate by a…
Ultrafine strontium barium niobate ((Sr x Ba 1− x )Nb 2 O 6 , SBN) powders were prepared using sol–gel and hydrolysis aging processes. Their structural properties were examined via X‐ray diffractometry and Raman spectroscopy. Our results indicated that the SBN powders crystallize to a pure tetragonal phase at annealin…
D,L-3-Methylglycolide (MG) was successfully polymerized with bimetallic (Al/Zn) μ-oxo alkoxide as an initiator in toluene at 90 °C. The effect of the initiator concentration and monomer conversion on the molecular weight was studied. It is shown that the polymerization of MG follows a living process. A kinetic study i…
Electroless Deposition of Thin-Film Cobalt-Tungsten-Phosphorus Layers Using Tungsten Phosphoric Acid ( H 3 [ P ( W 3 O 10 ) 4 ] ) for ULSI and MEMS Applications , Shacham-Diamand, Yosi, Sverdlov, Y., Petrov, N.
Nanocrystalline MgH2/MexOy composite powders were produced by high energy ball milling (MexOy=Sc2O3, TiO2, V2O5, Cr2O3, Mn2O3, Fe3O4, CuO, Al2O3, SiO2). The hydrogen absorption and desorption kinetics were determined in view of a technical application. The addition of selected oxides lead to an enormous catalytic acce…
A set of natural and heat-treated cordierite crystals has been analyzed using single-crystal X-ray diffraction, EMPA, SIMS, and 57Fe Mössbauer-spectroscopy. Structure determination of natural cordierite shows that the average size of the tetrahedrally coordinated T 1 1 cation increases systematically by about 0.01 Å a…
Amphiphilic dendritic–linear–dendritic triblock copolymers based on hydrophilic linear poly(ethylene oxide) (PEO) and hydrophobic dendritic carbosilane were synthesized with a divergent approach at the allyl end groups of diallyl-terminated PEO. Their micellar characteristics in an aqueous phase were investigated with…
A previously reported theoretical treatment for self-assembly macrocyclisations occurring under thermodynamic control has been tested experimentally. The fundamental quantities on which the treatment is based are the effective molarity (EM) of the self-assembling cyclic n-mer and the equilibrium constant for the inter…
A new organic conductor, β″-(BEDT-TTF)2SF5CHFCF2SO3 [BEDT-TTF, hereafter abbreviated ET, refers to bis(ethylenedithio)tetrathiafulvalene], was prepared by electrocrystallization. The crystal structure of this salt was determined by single crystal X-ray diffraction at 298 and 150 K, its physical properties were examine…
In this article we study the kinetics of thermal degradation of the epoxy system BADGE n = 0/m-XDA using different kinetic methods with data from thermogravimetric analysis (TGA) in dynamic conditions. Activation energies obtained using different integral methods (Flynn-Wall-Ozawa and Coats-Redfern Methods) are in goo…
Crystal structures of single crystals of ferroelectric Zn1−xLixO and paraelectric ZnO were studied by X-ray diffraction at 293K and 19K. At 293 K, the Zn-O bond length decreases by an amount of 0.007 Å along c-axis associated with Li-substitution. It is about two orders smaller than the changes in typical ferroelectri…
Regular patterns form in many solidification processes. Examples occur during lamella and rod-like eutectic growth and when single-phase cells or dendrites are formed. The scale and regularity of the microstructure can determine the properties of the cast materials and is thus important practically. The purpose of the…
The mixed valence cluster anion of the compound (NH4)32[MoVI110MoV28O416H6(H2O)58(CH3CO2)6].xH2O 1 (x approximately 250), synthesized under one-pot conditions, contains well-defined different types of defects--missing groups compared to the complete parent (Mo154) type cluster with full D7d symmetry--and acetate ligan…
This article deals with the structure, crystallization, morphology, and thermal behavior of poly(p-phenylene sulfide) (PPS) with low-molecular mass, probed by DSC, optical, and electron microscopy. The growth rates of spherulites were measured over the temperature range 235–275°C. A regime II–III transition was found…
Nanoparticles of chromium or nickel have been prepared by the reduction of either CrCl2 or Ni(acac)2 (acac = pentane-2,4-dionate) at elevated temperatures in various Lewis base solvents; the effect of the Lewis base, which acts as both a reaction solvent and passivating ligand on morphology are apparent; the nanostruc…
A microstructure function, G(x), is introduced as a general description of microstructure by considering simultaneously the spatial arrangement of phases, i(x), of crystallographic orientations, g(x), as well as of lattice defects and residual stress, D(x). Particular emphasis is laid on the orientation–location distr…