Materials Literature
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We discuss the implementation of quasiparticle calculations for point defects on semiconductor surfaces and, as a specific example, present an ab initio study of the electronic structure of the As vacancy in the +1 charge state on the GaAs(110) surface. The structural properties are calculated with the plane-wave pseu…
We discuss the properties of new superconducting compositions of Ru(1-x)Sr2RECu(2+x)O(8-d) (RE=Gd, Eu) ruthenocuprates that were synthesized at 600 atm. of oxygen at 1080 C. By changing ratio between the Ru and Cu, the temperature of superconducting transition (Tc) raises up to Tc max=72 K for x=0.3, 0.4. The hole dop…
The dependence of the magnetic susceptibility on the magnetic field is investigated for the single molecular magnet [Mn(hfac)$_2$NITPh]$_6$. The spikes of the susceptibility detected in a magnetic field ranging from 90 T to 285 T are interpreted as a manifestation of magnetic quantum jumps under spins reorientation fr…
SUMMARY 1. Diatoms were collected from 49 sites located on 23 rivers and identified to species. We defined 26 attributes of the diatom assemblage on the basis of tolerance and intolerance, autecological guild, community structure, morphological guild and individual condition. 2. We grouped sites into three geographica…
We have synthesized a series of liquid crystalline/isotropic block copolymers with narrow molecular weight distribution and with well-defined chemical structure. Block volume fractions were varied systematically. The domain structure of these compounds was determined by means of small-angle X-ray scattering. Spherical…
During FCC catalyst regeneration, part of the nitrogen in coke forms NO x, which makes up a significant part of the total NO x refinery emissions. The addition of a small percentage (≤1 wt %) of catalytic additive(s) in the FCC inventory can reduce the NO x emissions from the flue gases of the FCC regenerator. In this…
Octahedral, six-coordinate Co(2+) can exist in two spin states. For biological ligands, H(2)O and NH(3), the most stable spin state is high spin (S = (3)/(2)). The difference in energy between high and low spin is dependent upon the ligand mix and coordination stereochemistry. High spin optimized geometries for these…
By means of a two-layered ONIOM (B3LYP/LANL2DZ:UFF) approach, we predicted the viable oxidation of the sidewalls of single-wall carbon nanotubes by transition metal oxide (OsO 4 ), which gives rise to osmate ester adducts on the nanotube sidewall. We believe that the as-formed osmate ester adducts can be a good starti…
The birefringence, refractive indices, and dielectric measurements have been carried out for the double- and triple-branched multipodes based on the carbosilazane cores. The orientational order parameters have been obtained using both the optical and the dielectric measurements. The dielectric response is identified t…
The preparation of both postfunctionalizable and chromic poly[3-(N-succinimido-p-phenylcarboxylate(tetraethoxy)oxy)-4-methylthiophene] is reported. The N-hydroxysuccinimide ester side group can easily react with different amine-bearing molecules in the solid state to yield a library of new polythiophene derivatives. T…
Hybrid copolymers with dendritic−linear blocks are shown to exhibit many of the classic microphase-separated structures of linear−linear block copolymers. Transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) were used to evaluate the morphology of a six…
Normal state conductivity and superconductivity together with bulk magnetic susceptibility and magnetization measurements have been measured for two molecular charge-transfer salts: beta' '-(ET)4[(H3O)Ga(C2O4)3]G (ET = bis(ethylenedithio)tetrathiafulvalene, G = pyridine for compound I and nitrobenzene for compound II)…
In situ UV−vis absorption spectroscopy is used to probe the extent of dissociation of a weak polycarboxylic acid incorporated within a polyelectrolyte multilayer. The effective acid dissociation constant is shown to depend on the nature of the multilayer. Salt counterion and proton populations within the multilayer ar…
Three novel 4,7-bis(n-pyridylethynyl)-2,1,3-benzothiadiazoles (n = 2, 3, and 4) were synthesized by using the Sonogashira cross-coupling reaction of 4,7-dibromo-2,1,3-benzothiadiazole with the corresponding ethynylpyridines in the presence of a Pd(II) catalyst. The viologen analogues were also prepared by methylation…
In the present work we report a detailed spectroscopic analysis of diffusive relaxation and vibrational properties of water in bulk and confined in nanopores of Gelsil glass, at different temperatures and different hydration percentages, performed by incoherent quasi-elastic and inelastic neutron scattering, IQENS and…
A "CBABC"-type pentablock coupling polymer, mesylMPEO, was designed and synthesized to promote human endothelial cell growth on the surfaces of polyurethane biomaterials. The polymer was composed of a central 4,4'-methylenediphenyl diisocyanate (MDI) coupling unit and poly(ethylene oxide) (PEO) spacer arms with methan…
The absorption spectra of zinc porphyrin, zinc meso -tetraphenylporphyrin, and their β-halogenated derivatives are calculated and analyzed using time-dependent density functional theory (TDDFT) and time-dependent Hartree−Fock theory based on the intermediate neglect differential overlap/spectroscopic approximation (TD…
Pt(0)-catalyzed ring-opening precipitation copolymerization of [1]silaferrocenophanes fcSiMe(2) (3) and the spirocyclic cross-linker fcSi(CH(2))(3) (4) (fc = Fe(eta(5)-C(5)H(4))(2)) was used to prepare polyferrocenylsilane microspheres (PFSMSs) under mild conditions. By varying the reaction conditions, a wide variety…
Both cubic and hexagonal phases of ZnS are modeled using interatomic potential based simulations and density functional theory. A new set of potential parameters is derived, showing improved behavior compared with the previous ones. Results obtained with this new potential model show very good agreement with those obt…
A novel approach for the potentiometric detection of saccharides using poly(aniline boronic acid) is presented. A model is described in which the electrochemical potential is sensitive to the change in the pK(a) of the conducting polymer as a result of boronic acid-diol complexation. In this system, boronic acid compl…