Materials Literature
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Spectroscopic, structural, and magnetic data are presented for Fe(C(3)H(4)N(2))(6)(NO(3))(2), which facilitate a precise definition of the electronic and molecular structure of the [Fe(Im)(6)](2+) cation. The structure was determined at 120(1) K by X-ray diffraction methods. The salt crystallizes in the trigonal space…
The reversible, stepwise formation of individual Nb-mu-O-Nb linkages during acid condensation of 2 equiv of A-alpha-[SiNb(3)W(9)O(40)](7-) (1) to the tri-mu-oxo-bridged structure A-alpha-[Si(2)Nb(6)W(18)O(77)](8-) (4) is demonstrated by a combination of X-ray crystallography and variable-pD solution (183)W and (29)Si…
Solvent dependence of the electronic structure and nonlinear optical properties of the para-nitroaniline (pNA) molecule on the polarity of the solutions has been studied using the polarizable continuum model in combination with the hybrid density functional theory. With a supermolecular approach, specific hydrogen bon…
Recent experimental studies on nanocrystalline metals have shown that mechanical strength may decrease with decreasing grain size d for d<10–15 nm. The mechanisms underlying this trend are not understood, although such a relationship is in distinct contrast to that seen in microcrystalline metals whereby streng…
Structure transformations for crystalline bundles of single walled carbon nanotubes (10,10), (8,8), and (6,6), in response to external pressure are modeled by first-principles calculations. Upon pressure, the circular tube section is first transformed into an elliptical shape. Further pressure then leads to a flattene…
The dynamic hysteresis response of ferroelectric SrBi2Ta2O9 thin films versus periodically varying electric field over a frequency range of f=10−1–106 Hz and amplitude range of E0=15–158 kV/cm is measured utilizing the Sawyer–Tower method. The dynamic order parameter Q shows anomalous behavior against the field amplit…
We report a very large enhancement of the thermopower of 4 nm diameter metallic Zn nanowires, with a temperature dependence that is consistent with that of their electrical resistivity and the Mott formula. The temperature dependence of the resistance, magnetoresistance, and thermopower of composites consisting of 15,…
We present a detailed study of the growth of Ge nanocrystals (NCs) on SiO2 by chemical vapor deposition. A two-step process was developed. First, Si nuclei are deposited on SiO2 using SiH4 as a gaseous precursor. Then, Ge NCs grow selectively on the Si nuclei previously formed. The density of the Ge NCs is adjustable…
Mechanical properties of meso-porous silicon are studied using topographic measurements and finite element simulations. Our approach is based on an original analysis of the strain at the free surface of porous silicon tub embedded in bulk Si regions allowing the determination of the Young’s modulus of the porous layer…
Acid soluble collagen (ASC) and a cattle hide gelatine were analyzed by size exclusion chromatography (SEC) coupled with multi angle light scattering (MALS). The SEC system was calibrated with ASC and its cyan bromide cleavage products. The accuracy of calibration was confirmed by MALS by measuring the mass-average mo…
The nonideal behavior of the transport properties of water–dimethyl sulfoxide (DMSO) mixtures has been studied through equilibrium and nonequilibrium molecular dynamic simulations. The shear viscosity and thermal conductivity of the mixture has been analyzed and compared with available experimental data at ambient con…
Five-coordinate halido- and pseudohalido-bis(o-iminobenzosemiquinonato)iron(III) complexes [Fe(III)X(L(ISQ))(2)] (X = Cl(-) (1), Br(-) (2a, 2b), I(-) (3), N(3)(-) (4), and NCS(-) (5)) have been synthesized where (L(ISQ))(1)(*)(-) represents the pi radical anion N-phenyl-o-imino(4,6-di-tert-butyl)benzosemiquinonate(1-)…
The very high speed of collapse of cavitation bubbles is responsible for a number of phenomena of interest in science and engineering: Luminescence, sonochemistry, cavitation damage, ultrasonic cleaning, etc. Strongly forced bubbles may collapse with such violence that the relatively slow processes of diffusion of the…
Silicon nanotips with tip diameter and height measuring 1 nm and 1 μm, respectively, and density in the range of 109–3×1011 cm−2, were fabricated monolithically from silicon wafers by electron cyclotron resonance plasma etching technique at a temperature of 200 °C. Field emission current densities of 3.0 mA/cm2 at an…
A series of layered oxysulfides, LnCuOS (Ln = La∼Nd), was studied to examine the influence of these lanthanide ions on their optical and electrical transport properties. PrCuOS and NdCuOS showed wide-gap p-type semiconducting properties similar to LaCuOS, which is a p-type semiconductor with an energy gap of 3.1 eV. A…
Computer modeling techniques were employed to investigate the adsorption of a selection of organic molecules to a series of monatomic growth steps of the major calcium carbonate polymorph calcite. Incorporation of the organic material by replacement of preadsorbed water at calcite {101̄4} surface features is calculate…
In solution, CdSe quantum dot exciton recombination is composed of an intrinsic band edge exciton decay and a photoinduced charged exciton, which produces the observation of biexponential decay dynamics. The nearly identical radiative lifetimes of both intrinsic and extrinsic decays scale with the cube of the size, an…
We report a first observation of nanoscale surface structures of segregated pinned micelles of grafted Y-shaped molecules and their reversible structural reorganization. We designed a novel type of Y-shaped molecules combining two highly incompatible polymer chains (arms) attached to a single focal point capable of ch…
Complex BaCO 3 superstructures can be easily generated by using poly(sodium 4-styrenesulfonate) (PSS) and poly(allylamine hydrochloride) (PAH) as structure directing agents in the mineralization process. More complex macroporous superstructures could be generated by cooperative templating effects of the molecular temp…
Novel bolaamphiphiles consisting of a rigid biphenyl unit, two terminal polar 1,2-diol units and laterally attached (semi)perfluorinated chains have been synthesized via palladium-catalyzed cross coupling reactions as the key step. The thermotropic liquid crystalline behavior of these compounds was investigated by pol…