Materials Literature
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Taking into account some attractive properties of the thorium phosphate−diphosphate (Th 4 (PO 4 ) 4 P 2 O 7 ), called TPD, we focused our research on its potential use as a ceramic for the long term storage of some radionuclides including trivalent and tetravalent actinides. In this objective, we already investigated…
It is well known that ${\mathrm{sp}}^{2}$ bonding in carbon can result in stable cage structures, but pure Si clusters with similar cage structures are unstable. Using first-principles calculations, we show that a dodecahedral cage of silicon can be stabilized dynamically as well as energetically by doping with Ba, Sr…
Motivated by recent magnetic measurements on ${A}_{3}{\mathrm{Cu}}_{3}({\mathrm{PO}}_{4}{)}_{4} (A=\mathrm{Ca},\mathrm{Sr})$ and $\mathrm{Cu}(3\mathrm{\ensuremath{-}}\mathrm{Clpy}{)}_{2}({\mathrm{N}}_{3}{)}_{2}$ $(3\mathrm{\ensuremath{-}}\mathrm{Clpy}=3\mathrm{\ensuremath{-}}\mathrm{Chloropyridine}),$ both of which be…
Complex ring (13)C resonance lines of the cross-polarization/magic angle spinning (CP/MAS) (13)C NMR spectra of cellulose triacetate (CTA) I and CTA II were completely assigned, for the first time, by (13)C-enriched CTA allomorphs. The (13)C-enriched CTA I was prepared by heterogeneous acetylation of bacterial cellulo…
Transparent, aqueous colloidal titanate solutions were prepared by a reaction between titanium alkoxide and alkylamines or tetraalkylammonium hydroxides. The chemical species containing titanium atoms were found to be a colloidal particle (15 nm) with a layered structure. The formation reaction can be explained as an…
A mesoporous siliceous material of MCM-41 type was characterized by nitrogen adsorption, X-ray diffraction, and Fourier transform infrared spectroscopy. Its pore diameter, external and internal surface, pore volume, wall thickness, and pore wall density were determined. Special attention was paid to sample aging and i…
Two new pentadentate, pendent arm macrocyclic ligands of the type 1-alkyl-4,7-bis(4-tert-butyl-2-mercaptobenzyl)-1,4,7-triazacyclononane where alkyl represents an isopropyl, (L(Pr))(2-), or an ethyl group, (L(Et))(2-), have been synthesized. It is shown that they bind strongly to ferric ions generating six-coordinate…
The "3 + 1" variant of the MacDonald condensation has been shown to be an excellent methodology for synthesizing carbaporphyrins. In particular, 1,3-indenedicarbaldehyde condenses with tripyrranes in the presence of TFA to give, following oxidation with DDQ, a series of benzocarbaporphyrins in excellent yields. Trifor…
We investigate the melting process of a two-dimensional charge-stabilized colloidal system in the presence of a triangular substrate potential. This potential is formed by an optical interference pattern that allows the substrate strength to be varied continuously. By means of an additional scanned optical tweezer the…
The controlled assembly of nanoparticles in thin film form on solid supports, both as monolayers and as superlattice structures, is a problem of considerable topical interest. Among the many interactions used to program the assembly of nanoparticles, electrostatic forces are particularly interesting for many reasons.…
We present results of molecular dynamics simulations on lithium metasilicate over a broad range of temperatures for which the silicate network is frozen but the lithium ions can still be equilibrated. The lithium dynamics is studied via the analysis of different correlation functions. The activation energy for the lit…
The results of the X-ray photoelectron spectroscopy studies of the electronic structures of trifluorides, oxides and other compounds of Sc, Y and lanthanides (Ln) from La to Lu, except for Pm, in the binding energy range from 0 to 1350 eV are generalised. The established dependences of the Ln4f binding energies and th…
The structure and physical properties of the Zr-stabilized, nonstoichiometric molybdenum diboride superconductor are reported. Good quality material of the diboride structure type can only be obtained by partial substitution of Zr for Mo, and the quenching of melts. The phase is best made with boron in excess of the i…
A heterometallic polyoxometalate [Co(en)2][Co(bpy)2]2[PMoVI5MoV3VIV8O44]·4.5H2O (en = ethylenediamine, bpy = 2,2′-bipyridine) 1, has been hydrothermally synthesized, which is the first example of a two-dimensional framework where polyoxometalate anions are linked by two types of complex fragments.
The redox potentials of bis(fulvalene)dinickel, 1, and the tetrakis(ferrocenyl)nickel dithiolene complex 2 have been measured in a variety of nonaqueous electrolytes. The difference in E1/2 values of the two successive one-electron oxidations of 1 (i.e., DeltaE1/2 values) increased from a low of 212 mV in anisole/[NBu…
The precise assignments of cross polarization/magic angle spinning (CP/MAS) (13)C NMR spectra of cellulose I(alpha) and I(beta) were performed by using (13)C labeled cellulose biosynthesized by Acetobacter xylinum (A. xylinum) ATCC10245 strain from culture medium containing D-[1,3-(13)C]glycerol or D-[2-(13)C]glucose…
We theoretically study the development of spontaneous magnetization in diluted magnetic semiconductors as arising from a percolation of bound magnetic polarons. Within the framework of a generalized percolation theory we derive analytic expressions for the Curie temperature and the magnetization in the limit of low ca…
Understanding factors that affect the potassium (K) status of soil is important to chemical prediction of plant-available K in corn (Zea mays L.). Soils vary widely in their ability to replenish labile K from nonlabile forms. No research has been done to investigate the effects clay fraction mineralogy of South Dakota…
This paper presents piezoelectricity in germanium-doped silica (germanosilicate) films produced by poling treatment. The germanosilicate films were prepared on Si substrates by RF magnetron sputtering. The films were poled by electric fields of 2–4 ×10 7 V/m at a temperature above 300°C. Before the poling, no piezoele…
The electrical response of defect centres, which are distributed randomly in space and interact via electrostatic forces, is examined by Monte Carlo simulation of dipolar lattice gas models. Coulomb interactions are found to have a profound influence on the a.c. conductivity or the dielectric loss spectrum, when the i…