Materials Literature
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Thermogravimetric analysis (TGA), through measurements of mass volatilized as a function of time, is an essential method for understanding pyrolysis of macromolecular materials. In this paper, we show that two differential equations for mass and moles of test sample allow interpretation of isothermal and nonisothermal…
We deduce a model relevant for the description of the ferromagnetic half-metal chromium dioxide $({\mathrm{CrO}}_{2}),$ widely used in magnetic recording technology. The model describes the effect of dynamical, local orbital correlations arising from local quantum chemistry of the material. A finite-temperature soluti…
Sound velocity and attenuation in liquid sulfur have been measured at temperatures from 80 \ifmmode^\circ\else\textdegree\fi{}C in the super cooled state through the melting temperature (about 120 \ifmmode^\circ\else\textdegree\fi{}C) to 200 \ifmmode^\circ\else\textdegree\fi{}C under saturated pressure. The measuremen…
The ruthenium complex of tetratolyldithiaporphyrin was synthesized and characterized. The solid-state structure demonstrates that, in order to accommodate ruthenium metal in the central core, the thiophene rings tilt away from the dithiaporphyrin core and coordinate to metal in an η1-pyrimidal side-on fashion.
BACKGROUND: Computational predictions are critical for directing the experimental study of protein functions. Therefore it is paradoxical when an apparently erroneous computational prediction seems to be supported by experiment. RESULTS: We analyzed six cases where application of novel or conventional computational me…
Electronic structure calculations of magnetic properties for Mn-based alloys are performed. The full-potential linear augmented-Slater-type-orbital implementation of the local-density approximation is employed. Theoretical predictions for magnetic moments of ${\mathrm{Mn}}_{x}{\mathrm{Fe}}_{4\ensuremath{-}x}Y$ $(Y=\ma…
TS-1 and Fe-MFI systems have been chosen as cases studies for describing the behavior of single-site catalysts. We will report a concise review of the firmly established knowledge and of the open problems concerning the structure and the reactivity of Ti and Fe sites in TS-1 and Fe-MFI in partial oxidation catalysts.…
Ultrasonic non-destructive evaluation (NDE) plays an increasingly important role in determining properties and detecting defects in composite materials, and the analysis of wave behavior is crucial to effectively using NDE techniques. The complexity of elastic wave propagation in anisotropic media has led to a relianc…
Dinuclear oxovanadium(IV) complexes bridged by pyrimidine derivatives, L[VO(hfac)(2)](2) [L = pyrimidine (PM), 4-methylpyrimidine (MPM), 4,6-dimethylpyrimidine, 4-aminopyrimidine, and quinazoline; hfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate], were synthesized and characterized. All of them showed intramolecular f…
Phosphine oxides 1 − 5 bearing one, two, or three hydrolyzable Si(OR) 3 groups have been prepared. They were treated with anhydrous europium salts [Eu(NO 3 ) 3 or EuCl 3 ] to afford complexes 6 − 10, the stoichiometry of which was found to be one Eu 3+ for three P O centers. The hydrolytic polycondensation of these co…
Ball milling of crystalline cellulose with maleated polyethylene (MPE) yields a novel composite with ester bonds formed by reaction of the hydroxy groups of the cellulose with the maleic anhydride groups of MPE; the composite exhibits much improved toughness and ductility compared with the product formed by melt-mixin…
The total electronic energy and nucleus-independent chemical shift (NICS) of 95 isomers of N-confused porphyrin (NCP: normal porphyrin (N(0)CP), singly N-confused porphyrin (N(1)CP), doubly N-confused porphyrin (N(2)CP), triply N-confused porphyrin (N(3)CP), and fully N-confused porphyrin (N(4)CP)) have been calculate…
The structure and the electronic properties of a sodium tetrasilicate $({\mathrm{Na}}_{2}{\mathrm{Si}}_{4}{\mathrm{O}}_{9})$ glass were studied by combined Car-Parrinello and classical molecular dynamics simulations. The glass sample was prepared using a method recently employed in a study of a silica glass [M. Benoit…
An inherent structure analysis of viscosity is developed based on results of nonequilibrium molecular dynamics simulations. The viscosity is separated into a "structural" contribution associated with the energy minima that the system visits, and a "vibrational" contribution associated with displacements within the ene…
Periodic large mesopore organosilicas have been obtained for the first time using bridged silsesquioxane (RO)3SiCH2CH2Si(OR)3 precursors and triblock copolymers as structure-directing species in acid media.
Resistance measurements have been performed to investigate the superconducting state for an organic superconductor $(\mathrm{TMET}\ensuremath{-}\mathrm{STF}{)}_{2}{\mathrm{BF}}_{4}$ with ${T}_{c}=4.1\mathrm{K}.$ The upper critical magnetic fields parallel and perpendicular to the conduction plane are determined and di…
Abstract Several batches of chars were prepared from palm shell by carbonization in a flow of nitrogen using a fixed‐bed reactor. Palm shell was carbonized at temperatures of 500, 600, 700, 800 and 900 °C for 1 h to study the effects of carbonization temperature on char yield and its porosity. The prepared chars were…
A theory of the anisotropic superexchange and low-energy spin excitations in a Mott insulator with ${t}_{2g}$ orbital degeneracy is presented. We observe that the spin-orbit coupling induces frustrating Ising-like anisotropy terms in the spin Hamiltonian, which invalidate noninteracting spin-wave theory. The frustrati…
The novel complex trans-Cu(hfac)2(TTF-py)2 (hfac = hexafluoroacetylacetonate; TTF-py = 4-(2-tetrathiafulvalenyl-ethenyl)pyridine) in which the paramagnetic transition metal and the organic donor are covalently linked through a conjugated bridge is synthesized and characterized aiming at a new approach for the occurren…
We present an analysis of the vibrational dynamics of metal vicinal surfaces using the embedded atom method to describe the interaction potential and both a real space Green's function method and a slab method to calculate the phonons. We report two main general characteristics : a global shift of the surface vibratio…