Materials Literature
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The preparation of carbon nanotube (CNT) materials with high purity is critical for many potential applications. These materials not only need to be free of carbonaceous impurities but also have uniform diameters. Within the CNT family, double-walled carbon nanotubes (DWNTs), as the simplest member of multiwalled carb…
A series of eight dimethoxybenziporphyrins were prepared in three steps from 1,3-dimethoxybenzene or 2,6-dimethoxytoluene. Dibromination, followed by lithium-halogen exchange and reaction with benzaldehyde gave dicarbinol intermediates. These reacted with pyrrole and aryl aldehydes in the presence of BF3.Et2O in chlor…
Spin-probe and spin-label techniques were used to study the interactions of the Abeta 1-28 peptide involved in Alzheimer disease and the PrP 106-126 peptide suspected to be preferentially involved in spongiform encephalopathies with three different types of dendrimers. A computer-aided EPR analysis of a positively cha…
Polar nanoregions in relaxor ferroelectrics were modeled by the Monte Carlo method. To account for correlations between atomic shifts, Potts-like models were applied with a random field used to mimic the chemical disorder impact on the polar ordering. The diffuse scattering effects for generated structures were calcul…
Carbon nanotubes, even after extensive posttreatment, contain metallic impurities which may produce misleading results, giving rise to false claims of the properties of carbon nanotubes. To overcome this, we report on high-purity catalyst-free multiwalled carbon nanotubes which have been explored with transmission ele…
The pressure-dependent structure and functionality of the coordination framework material zinc cyanide, Zn(CN) 2, has been explored using in situ neutron powder diffraction. A third-order Birch−Murnaghan equation of state fit to variable pressure (0−0.6 GPa) data collected at ambient temperature ( K 0 = 34.19(21) GPa,…
Abstract A magnetic suspension balance was employed in experiments to measure gas solubility in the polymer melts. The gas solubilities of CO 2 and N 2 in both linear and branched Polypropylene (PP) were investigated. The swollen volumes predicted by the Sanchez–Lacombe equation of state (EOS) and Simha–Somcynsky EOS…
A family of bis(imino)pyridine iron neutral-ligand derivatives, ((iPr)PDI)FeL(n) ((iPr)PDI = 2,6-(2,6-iPr2-C6H3N=CMe)2C6H3N), has been synthesized from the corresponding bis(dinitrogen) complex, ((iPr)PDI)Fe(N2)2. When L is a strong-field ligand such as tBuNC or a chelating alkyl diphosphine such as DEPE (DEPE = 1,2-b…
Periodic density functional theory (DFT) calculations using plane-wave basis sets were performed in order to study the bulk of nickel ferrite NiFe2O4. The local spin density approximation (LSDA) and the generalized gradient approximation (GGA) formalism were used, and it appeared that the LSDA failed to describe the m…
Colloidal, monodisperse, single-crystalline pyramidal CuInS2 and rectangular AgInS2 nanocrystals were successfully synthesized through a convenient and improved solvothermal process that uses hexadecylamine as a capping reagent. The crystal phase, morphology, crystal lattice, and chemical composition of the as-prepare…
Abstract Summary : Haloferax mediterranei was investigated for the production of two different high‐performance polyhydroxyalkanoates (PHAs). A copolyester containing 6 mol‐% 3‐hydroxyvalerate (3HV) was produced from whey sugars as sole carbon source. The maximum specific growth rate ( µ max. ) and the maximum specifi…
Resistive oxygen sensors based on gallium oxide were fabricated in order to analyze their sensing performances (as sensitivity, response, and recovery time) in an oxygen atmosphere at 1000°C. We prepared three types of sensors using a β‐Ga 2 O 3 single crystal in a sandwich structure with Pt pad electrodes and β‐Ga 2…
Ordered mesoporous nanocrystalline titanium-carbide/carbon composites are synthesized by using a solvent-evaporation-induced self-assembly process combined with in situ carbothermal reduction (see figure). The composites comprise crystalline titanium carbides confined in a matrix of amorphous carbon pore walls. The na…
The dynamic behavior of nanoscale mesoporous oxide materials exposed to aqueous solutions under biologically relevant conditions is shown to be highly dependent on composition, porosity, and calcination temperature. Dynamic processes were followed as a function of exposure on thin oxide films amenable to environmental…
Ideal models of complex materials must satisfy all available information about the system. Generally, this information consists of experimental data, information implicit to sophisticated interatomic interactions and potentially other {\it a priori} information. By jointly imposing first-principles or tight-binding in…
Waves propagating inwardly to the wave source are called antiwaves which have negative phase velocity. In this paper the phenomenon of negative phase velocity in oscillatory systems is studied on the basis of periodically paced complex Ginzbug-Laundau equation (CGLE). We figure out a clear physical picture on the nega…
There are many materials whose dielectric properties are described by a stretched exponential, the so-called Kohlrausch-Williams-Watts (KWW) relaxation function. Its physical origin and statistical-mechanical foundation have been a matter of debate in the literature. In this paper we suggest a model of dielectric rela…
We report the magnetic and thermal properties of Dy2Sn2-xSbxO7+x/2, x = 0, 0.25, and 0.5, and Dy2NbScO7. We find evidence for Ising-like single ion ground states in the Dy2Sn2-xSbxO7+x/2 materials. These materials possess nearly the same zero point entropy as the canonical spin ices Ho2Ti2O7 and Dy2Ti2O7, strongly sug…
We study the two-impurity Anderson model for a semiconductor host using the quantum Monte Carlo technique. We find that the impurity spins exhibit ferromagnetic correlations with a range which can be much more enhanced than in a half-filled metallic band. In particular, the range is longest when the Fermi level is loc…
A two-channel switchable nanoscopic hybrid system, able to modulate mass transport by photoresponsive appended organic groups and the presence of G1.5 PAMAM dendrimers as molecular caps, is reported. This new functional gatelike ensemble is chemically (by pH changes) and photochemically (using visible light) controlle…