Materials Literature
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Hyper-branched polymers (HBP) can be prepared in one-pot poly- reactions from ABx monomers. These polymers exhibit specific properties due to their globular, highly functional structure and are of significant interest due to their main potential applications in blends, coatings or resins, or as additives to linear pol…
Both high-frequency acoustic modes and the boson peak related to ${\mathrm{SiO}}_{4}$ librations are observed in a single inelastic x-ray scattering experiment. The experimental data are consistent with a picture where the acoustic modes experience a crossover at a frequency ${\ensuremath{\Omega}}_{\mathrm{co}}$ beyon…
In this study the fusion method was used to synthesize PbS nanocrystal quantum dots (QDs) embedded in S-doped glass matrix (SiO 2 −Na 2 CO 3 −ZnO−Al 2 O 3 −PbO 2 −B 2 O 3 ). Optical absorption, atomic force microscopy (AFM), and photoluminescence (PL) were used to investigate different samples. Experimental data indic…
<div class="htmlview paragraph">To increase crash performance in automotive vehicles it is necessary to use new techniques and materials. Components linked to crash safety should transmit or absorb energy. The energy absorbing capability of a specific component is a combination of geometry and material propertie…
The methods presented allow vacuum-tight microstructured components to be produced, in which the microchannel walls are provided with aluminum oxide coatings. These coatings have a large surface area and may be applied as catalyst carriers for heterogeneously catalyzed reactions, as was demonstrated by the catalytic c…
The buildup and structure of multilayer films containing cationic polyelectrolyte and silica nanoparticles have been studied by means of ellipsometry, atomic force microscopy, and X-ray photoelectron spectroscopy. Emphasis was placed on the effect of ionic strength on the adsorption behavior and structure formation. C…
The chemisorption of molecules on metal oxide surfaces is generally considered to occur by either an acid/base or a redox mechanism, with the former dominating on nonreducible and insulating oxides such as MgO. NO, NO 2, and the less familiar NO 3 are atypical adsorbates in that their most potent Lewis acidic and basi…
Abstract Acrylic/nano‐silica composite latexes were prepared by blending via high shear stirring (SS) or ball milling (BM) and in situ polymerization (IS). For comparison, composites filled with micro‐silica were also prepared. The mechanical and optical properties of the polymers formed by the composite latex filled…
MgO nanowires with uniform diameter distribution of about 20 nm have been synthesized by boron oxide-assisted catalytic growth method. X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy were used to characterize the structure and defects. The results indicate that MgO…
We have developed specially designed semiconductor devices for the measurement of thermal conductance in suspended nanostructures. By means of a novel subtractive comparison, we are able to deduce the phonon thermal conductance of individual nanoscale beams of different geometry and dopant profiles. The separate roles…
Regular honeycomb-structured porous films can be prepared by the casting of a polymer solution under humid conditions. The origin of these pores is `empty' water droplets, which condense from the humid atmosphere onto the solution. The water droplets self-organize into a regular array and serve as a highly regular tem…
Distortions of the $\sqrt3\times\sqrt3$ Sn/Ge(111) and Sn/Si(111) surfaces are shown to reflect a disproportionation of an integer pseudocharge, $Q$, related to the surface band occupancy. A novel understanding of the $(3\times3)$-1U (``1 up, 2 down'') and 2U (``2 up, 1 down'') distortions of Sn/Ge(111) is obtained by…
Metal−CdSe−metal (metal = Au, Ni) nanowires were grown by electrochemical replication of porous aluminum oxide and polycarbonate track etch membranes with pore diameters of 350 and 70 nm, respectively. The lengths of the individual segments of the nanowires were controlled by varying the amount of charge that was pass…
We revisit the theory of magnetoresistance for a system of nanoscopic magnetic granules in metallic matrix. Using a simple model for the spin dependent perturbation potential of the granules, we solve Boltzmann equation for the spin dependent components of the non equilibrium electronic distribution function. For typi…
We have observed a paramagnetic-to-ferromagnetic phase transition in short period InGaMnAs/InGaAs superlattices. The thicknesses of magnetic InGaMnAs layers in the structures studied was chosen to be 4 or 8 molecular layers (12 Åor 24 Å). The nonmagnetic InGaAs spacer layers are 12 Åthick. The In content of InGaMnAs a…
In this paper, we review the construction of low-dimensional manifolds of reduced description for equations of chemical kinetics from the standpoint of the method of invariant manifold (MIM). MIM is based on a formulation of the condition of invariance as an equation, and its solution by Newton iterations. A review of…
We have used a novel, high-pressure high-temperature scanning tunneling microscope, which is set up as a flow reactor, to determine simultaneously the surface structure and the reactivity of a Pt(110) model catalyst at semirealistic reaction conditions for CO oxidation. By controlled switching from a CO-rich to an O2-…
The low electron energy loss and complex dielectric functions of an arbitrary grain boundary and its proximity in ZnO thin films have been studied by using the spatially resolved electron energy loss spectroscopy. The critical point parameters have been determined by fitting the dielectric functions simultaneously wit…
The structure and electronic bonding in the spinel SiAlON (Si6−zAlzOzN8−z, z=1) derived from the cubic c-Si3N4 are studied by a first-principles density functional method. Al prefers the octahedral site of the spinel lattice. The small energy difference between the four possible structural configurations indicates tha…
The behavior of a diverse range of soils from Trinidad with respect to strongly fixed dynamics was studied. Fixed contents and additional ammonium fixation capacity (AAF) varied among the soils; the former increasing with clay content and ammonium fixation capacity (AFC) while the latter was related more to the soil's…