Materials Literature
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The synthesis, characterization, and X-ray structure of a heptapyrrolic macrocycle, [30]heptaphyrin(1.1.1.1.1.0.0) is reported; despite showing aromatic features, it exhibits a 'figure eight'-like structure in the solid state.
Spinel structure ${\mathrm{MnFe}}_{2}{\mathrm{O}}_{4}$ is investigated using density functional calculations. The ground state is a high spin ferrimagnet in agreement with experiment. The band structure shows a low carrier density half metal in the fully ordered state, in contrast to experimental characterizations of…
Synthesis and characterization of poly(quinoxaline vinylene)s and poly(pyridopyrazine vinylene)s with linear and branched aliphatic side chains are reported. The electron affinity of the polymers was measured with cyclic voltammetry (CV) and found to be highest for the pyridopyrazine vinylene polymers. Compared to CN-…
The magnetic and electrical transport properties and relative thermal expansion measurements on ${\mathrm{GdBaCo}}_{2}{\mathrm{O}}_{5.45}$ show the existence of a stabilized intermediate spin state of ${\mathrm{Co}}^{3+}$ in the temperature region $108 \mathrm{K}<~T<~365 \mathrm{K}.$ A charge ordering effect at…
We study the nonequilibrium fluctuation-dissipation theorem (FDT) in the glass phase of Bouchaud's trap model. We incorporate an arbitrary observable m and obtain its correlation and response functions in closed form. A limiting nonequilibrium FDT plot is approached at long times for most choices of m. In contrast to…
In this work we describe the evanescent waveguide characterization and photoalignment of azobenzene-functionalized dendrimer ultrathin films. Azobenzene dyes were grafted to the perimeter of polyamidoamine dendrimers. The photoisomerization and photoalignment properties were first investigated in relation to solution…
Abstract A phosphoric acid–pentaerythritol–melamine copolymer was selected as an intumescent flame retardant (IFR). The influence of α‐methacrylic acid grafted polypropylene (PP‐ g ‐MAA) on the properties and compatibility of IFR/PP composites was studied. The results obtained from mechanical tests and scanning electr…
The R-factor and R-free are commonly used to measure the quality of protein models obtained in X-ray crystallography. Well-refined protein structures usually have R-factors in the range of 20-25%, whereas intrinsic errors in the experimental data are usually around 5%. We use molecular dynamics simulations to perform…
Multilayered inorganic−organic hybrids were prepared by cohydrolysis and polycondensation of alkyltriethoxysilanes (C n TES, n = 8−18) and tetraethoxysilane (TEOS). Thin films were deposited from homogeneous solutions containing the oligomeric species by dip-coating. Self-assembly of co-condensed oligomers into lamell…
Abstract The direction of the transition dipole moments for the vibrations of the single W O W and double W O O W oxygen bridges in layered scheelite tungstates is derived from the Polarized infrared and Raman spectra of the KGd(WO 4 ) 2 single crystal. Their experimental values are compared with those obtained from t…
The Cd(C 5 F 6 HO 2 ) 2 ·2H 2 O complex was investigated by X-ray crystallography, mass spectroscopy, 1 H NMR spectroscopy, TG−DTG thermal measurements, and infrared transmittance spectroscopy. X-ray single-crystal data show that the cadmium ion is chelated by the oxygens of the hfa anion ligand and bound to the oxyge…
An organic radical, 1,3,5-trithia-2,4,6-triazapentalenyl (TTTA), exhibits a first-order phase transition between a paramagnetic high-temperature (HT) phase and a diamagnetic low-temperature (LT) phase, with a surprisingly wide thermal hysteresis loop over the temperature range 230--305 K. The crystal structure of the…
Binary mixtures of the aggregating helicene 1 with dodecane have, at dodecane concentrations >30 vol %, a nematic liquid crystalline phase and, at dodecane concentrations ≲5 vol %, a hexagonal columnar liquid crystalline phase. The helical structure with donor and acceptor groups at opposite ends gives rise to a molec…
The XPS (ESCA) method was employed to quantitatively determine polyelectrolyte adsorption on the mica basal plane from low ionic strength solutions. Particular emphasis was given to the effect of the polyelectrolyte charge density. By combining the results obtained from XPS and surface force measurements it was possib…
Water and oxygen molecules determine many of the properties of amorphous SiO2 used in several technologies, but the underlying atomic-scale processes remain unresolved. We report results of first-principles calculations showing that a wide range of behavior is possible in an amorphous environment, including diffusion…
Long-range effects on the pyroelectric coefficient of a ferroelectric superlattice consisting of two different ferroelectric materials are investigated based on the Transverse Ising Model. The effects of the interfacial coupling and the thickness of one period on the pyroelectric coefficient of the ferroelectric super…
Abstract Raman spectroscopy was used to determine the molecular behaviour of DMSO and DMSO‐ d 6 , and to compare it with that of DMSO in DMSO‐intercalated kaolinites. For DMSO at 298 K two bands are observed at 2994 and 2913 cm −1 and are assigned to the antisymmetric and symmetric CH stretching modes. At 77 K the deg…
Abstract Tensile tests on poly (methyl methacrylate) (PMMA) were conducted to clarify the effects of humidity and strain rate on tensile properties, particularly Young's modulus. Prior to the tensile tests, specimens were kept under various humidity conditions at 293 K, which were the same as the test conditions, for…
We derive a drift-diffusion equation for spin polarization in semiconductors by consistently taking into account electric-field effects and nondegenerate electron statistics. We identify a high-field diffusive regime which has no analogue in metals. In this regime there are two distinct spin diffusion lengths. Further…
Atomistic studies are carried out to investigate the formation and evolution of defects during nanoindentation of a gold crystal. The results in this theoretical study complement the experimental investigations [J. D. Kiely and J. E. Houston, Phys. Rev. B, v57, 12588 (1998)] extremely well. The defects are produced by…