Materials Literature
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An effective spin Hamiltonian is presented which describes the low-lying energy spectrum of antiferromagnetic molecular rings with high accuracy. It will be shown that for the particular case of the ferric wheels, quantum coherent phenomena are best discussed in terms of resonant quantum tunneling of the spin vector b…
[formula: see text] The influence of catalysts, acid chlorides, and solvents in the acylation of methyl 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate was studied. Conditions for the regioselective acylation processes were found. Thienopyrrole-based photochrome was synthesized for the first time.
We report on a photoinduced Faraday effect in an electrochemically synthesized cobalt-iron polycyanide film. When the Na0.36Co1.36[Fe(CN)6] ⋅4.7H2O film was irradiated with light from a Xe lamp, the Faraday rotation (FR) and Faraday ellipticity (FE) effects emerge suddenly over the 400–800 nm spectral change. The FR a…
A mononuclear [LaMnIIIOAc](ClO4)·0.5H2O [2(ClO4)·0.5H2O] complex with a new amino-containing pentadentate ligand LaH with a [N4O] coordination sphere has been obtained. Magnetic susceptibility measurements of 2(ClO4)·0.5H2O indicated a high spin electronic configuration for the MnIII ion. In cyclic voltammetry the rev…
We propose a protein crystal growth with stirring the solution, which is entirely different approach compared with the conventional method. The novel method, which we call the Floating And Stirring Technique (FAST), enables both growing crystals on an insoluble and very dense liquid without contacting the vessel and s…
In search of highly active nanoparticles for catalytic applications, flame aerosol technology turns out to be a promising method for its capacity to consistently produce highly pure nanoparticles. Starting with the production of simple oxides such as silica and titania in the forties, flame aerosol technology now faci…
Abstract The equilibrium and kinetics of proteins sorption and desorption by oppositely charged lightly crosslinked polyelectrolytes (#PE) were studied. The driving force of the sorption is provided by interpolyelectrolyte addition reaction (IPAR) between oppositely charged ionic groups of protein and #PE resulting in…
This work investigates the structure and stability of the pyrochlore solid solution Pb n Nb 2 O 5+ n using a combination of high‐resolution electron microscopy and electron diffraction. The microwave dielectric properties of the series 1.5 ≤ n ≤3.0 have been established, and the effect of the substitution of Ta 5+ for…
Abstract Two independent methods of crystal-size distribution analysis were compared: the Bertaut-Warren-Averbach XRD technique (MudMaster computer program) and high-resolution transmission electron microscopy (HRTEM). These techniques were used to measure thickness distributions of illite crystals (fundamental partic…
Abstract Light scattering has proved itself an efficient technique to determine particle diameters in heterogeneous dilute dispersions in the micrometer range. Extrusion of polymer blends is expected to give rise to very small particles, typically in the range from hundreds of nanometers to tens of micrometers. A ligh…
This paper presents an alternative approach aimed toward improvement of protective characteristics of gas-filled surge arresters (GFSA). Although so far GFSA with built-in radioactive sources proved to have superior protective characteristics, environmental concerns often challenge functional benefits. Experimental re…
Abstract Femtosecond fluorescence dynamics of trans ‐azobenzene in hexane have been investigated on excitation to the S 1 (n, π*) state at 432 nm using the up‐conversion technique. Two transient components were observed to represent the fast and the slow S 1 fluorescence dynamics in the wavelength range of 550–732 nm.…
The mesophase exhibited by four members of a new homologous series of compounds composed of banana-shaped molecules derived from 2-cyanoresorcinol is reported. The characteristic optical textures showing helical filamentary growth patterns, coupled with the results from X-ray diffraction studies of these seven-ring co…
We have used a sol−gel technique to obtain optically transparent hydrogels in which water is trapped within a tridimensional disordered silica matrix. A suitable aging of these hydrogels enables to have transparent noncracking samples down to cryogenic temperatures. We report the optical absorption spectra, in the nea…
Abstract Commercial products such as photographic materials and speciality papers manufactured by single or multilayer coating processes, all have some surface topographic structure. Nevertheless, for many materials, a uniform plane approximates their surface, and analyses of dynamic wetting, a fundamental physical pr…
Abstract Single‐wall nanotubes (SWNTs) embedded in polymer can be used as mechanical sensors because the position of the D* Raman band of SWNTs is strongly dependent on the strain transferred from the matrix to the nanotubes. In order to detect the stress (or strain) information in specific directions, polarized Raman…
We numerically analyze the origin of the transmission losses in left-handed structures. Our data confirms that left-handed structures can have very good transmission properties, in spite of the expectable dispersion of their effective permeability and refraction index. The large permittivity of the metallic components…
Commercially available α‐alumina powder with high‐purity, submicrometer particle size and narrow particle‐size distribution is used as starting material to prepare dense ceramic parts with transparent properties. The powder is dispersed and stabilized in a water‐based suspension. Controlled consolidation and drying by…
Abstract In this study, novel biodegradable polymers were synthesized by ring opening polymerization (ROP) of L ‐lactide on chitin in an N,N ‐dimethyl acetamide (DMAc)/lithium chloride (LiCl) solvent system, and chitin was used as macroinitiator to afford new materials. Lithium chloride (LiCl) was used as catalyst. Th…
We compare the vibrational properties of model SiO 2 glasses generated by molecular-dynamics simulations using the effective force field of van Beest et al. (BKS) with those obtained when the BKS structure is relaxed using an ab initio calculation in the framework of the density functional theory. We find that this re…