Materials Literature
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Carbonate is generally a strongly complexing ligand for f-element ions, including trivalent lanthanides. The few lanthanide(III) carbonates previously characterized have extended multidimensional solid state structures. Spectroscopic and solubility studies indicate that the solution species are monomeric; however, str…
Two different synthetic routes for the formation of sodium phenylsiloxanolate (SPS) have been developed: (i) the cleavage of oligo(phenylsilsesquioxane), OPSSO, by NaOH in n -butyl alcohol and (ii) the reaction of phenyltri- n -butoxysilane, PhSi( n -BuO) 3, and NaOH in n -butyl alcohol in the presence of water. From…
A systematic approach is proposed to structural characterization of templated nanoporous materials with cubic symmetry by gas adsorption. We hypothesize that regular structures of these materials can be described in terms of triply periodic minimal surfaces (TPMS), similarly to bicontinuous mesophases observed in oil−…
The vibrational structures of 4-nitro-azobenzene (NAB), 4-(dimethylamino)-azobenzene (DAB), and 4-nitro,4‘-(dimethylamino)-azobenzene (NDAB) are of interest due to their importance in optoelectronic applications as well as the unique isomerization mechanism involving the inversion process (at the nitrogen site). In th…
The giant magnetoresistance (GMR) of ferromagnetic bilayers with a superconducting contact (F1/F2/S) is calculated in ballistic and diffusive regimes. As in spin-valve, it is assumed that the magnetization in the two ferromagnetic layers F1 and F2 can be changed from parallel to antiparallel. It is shown that the GMR…
A shaped, magnetic ceramic was obtained from a metal-containing polymer network, which was synthesized by thermal polymerization of a metal-containing organosilicon monomer. Pyrolysis of a cylinder, shape, or film of the metal-containing polymer precursor produced a low-density magnetic ceramic replica in high yield.…
Spider flagelliform silk is one of the most elastic natural materials known. Extensive sequencing of spider silk genes has shown that the exons and introns of the flagelliform gene underwent intragenic concerted evolution. The intron sequences are more homogenized within a species than are the exons. This pattern can…
Dynamic heterogeneity is an active field of glass-transition research. The length scale of this heterogeneity is called the characteristic length. It can be calculated from complex heat capacity curves in the equilibrium liquid or from dynamic calorimetry curves corrected with regard to nonequilibrium. No molecular pa…
A bulk nanocrystalline (nc) pure copper with high purity and high density was synthesized by electrodeposition. An extreme extensibility (elongation exceeds 5000%) without a strain hardening effect was observed when the nc copper specimen was rolled at room temperature. Microstructure analysis suggests that the superp…
The structure of RuO(2)(110) and the mechanism for catalytic carbon monoxide oxidation on this surface were studied by low-energy electron diffraction, scanning tunneling microscopy, and density-functional calculations. The RuO(2)(110) surface exposes bridging oxygen atoms and ruthenium atoms not capped by oxygen. The…
Bulk quantities of defect-free silicon (Si) nanowires with nearly uniform diameters ranging from 40 to 50 angstroms were grown to a length of several micrometers with a supercritical fluid solution-phase approach. Alkanethiol-coated gold nanocrystals (25 angstroms in diameter) were used as uniform seeds to direct one-…
Distinct holes are found in the blue emission from KCl co-doped with divalent and trivalent europium ions. This extraordinary emission feature is associated with the process of reabsorption from Eu 2+ to Eu 3+ ions in KCL.
To understand the contribution of spacer structure toward electron transfer (ET) and to regulate electronic coupling between a redox pair, porphyrin−spacer−benzoquinone molecules were prepared where spacers are trans -decalin and dihalosubstituted tricyclo[4.4.1.0]undecane including a three-membered ring. These compou…
The aim of the present work is to investigate by molecular dynamics (MD) calculations the interaction between a moving edge dislocation in an -Fe crystal and a copper precipitate. In the absence of external stresses, two edge dislocations with the same slip plane and opposite Burgers vectors within a perfect -Fe cryst…
The first metalated porphyrazinediols 11 have been prepared from (L)-(+)-dimethyl tartrate via conversion into the corresponding dispoke or 2,3-dimethoxy-2,3-butanediyl protected 2,3-dihydroxymaleonitrile, Linstead macrocyclization, transmetalation, and deprotection. Their stability is very dependent on the nature of…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTUltraselective Epoxidation of Butadiene on Cu{111} and the Effects of Cs PromotionJames J. Cowell, Ashok K. Santra, and Richard M. LambertView Author Information Department of Chemistry, University of Cambridge Cambridge CB2 1EW, England Cite this: J. Am. Chem. Soc. 20…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDirect Observation of Sol−Gel Conversion: The Role of the Solvent in Organogel FormationRong Wang, Cristina Geiger, Liaohai Chen, Basil Swanson, and David G. WhittenView Author Information Bioscience Division, Los Alamos National Laboratory Los Alamos, New Mexico 87545…
The crystal structure of partially Pd 2+ -exchanged zeolite X, dehydrated at 400 °C in a flowing O 2 stream ( a = 24.982(4) Å), has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd 3̄ at 21(1) °C. The crystal was first Pd 2+ -exchanged in a flowing stream of 0.05 M aqueous Pd(…
No doubt: A perfect coating has to look brilliant! But other properties of coatings are also most important. Coatings have to be durable, tough and easily applicable. Additives are the key to success in achieving these characteristics, even though the amounts used in coating formulations are small. It is not trivial a…
An isotropic half-metallic double exchange magnet with a direct superexchange coupling between the localized spins is studied within the spin-wave (1/S) expansion. The momentum dependence of the spin wave spectrum (including quantum corrections) in the ferromagnetic phase at T=0 is investigated. Based on the calculate…