Materials Literature
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Flower- or cake-shaped particles with uniform particle size ranging from nanometers to micrometers were prepared from the stereo multiblock copoly(rac-lactide)s (smb-PLAs) by precipitating the polymer from its solution in methylene chloride/ethanol via three different methods: slowly lowering the solution temperature,…
Visible light irradiation of 5-acyloxymethyl- and 5-phenoxymethyl-2-pyrrolidino-1,4-benzoquinones effects photoisomerization to labile oxazolidines, which undergo elimination of carboxylate or phenolate leaving groups in high yields to generate trappable o-quinone methide intermediates. [reaction: see text]
A complete procedure for the preparation of clean surfaces of especially hard ionic crystals by ultrahigh vacuum (UHV) cleavage is given and exemplified by the preparation of the (001) surface of single MgO crystals. All important tools that are needed for the preparation are explained in detail. We present a device t…
MoO3 thin films were fabricated in this work by the laser evaporation method operating in continuous wave mode. The samples were prepared at different substrate temperatures, in vacuum and at different oxygen pressures. Oxidation states of the films were obtained by X-ray photoelectron spectroscopy (XPS) and the cryst…
Discrete transition-metal nanoparticles are spontaneously formed on the sidewalls of single-walled carbon nanotubes (SWNTs), which are noncovalently functionalized with 2,2′;6,2′′-terpyridine (Terpy). Such nanotubes are electron-rich hybrid systems, which overcome the energy barrier that prohibits spontaneous electron…
We report the synthesis of aligned N-doped carbon nanotube bundles via CVD (over the temperature range 700−800 °C) using ammonium-exchanged zeolite-β as the substrate, ferric nitrate as the catalyst, and acetonitrile as the carbon precursor. Ammonium exchange of the zeolite was found to be necessary for the formation…
We report on band gap states in C-doped TiO2 films that were prepared by oxidative annealing of sputtered TiC films at 550°C in flowing O2 gas. Deep-level optical spectroscopy measurements revealed three deep levels located at ∼0.86, ∼1.30, and ∼2.34eV below the conduction band. The first level is probably attributabl…
Bundles of single-walled carbon nanotubes are cut by applying a focused energetic electron beam. During cutting, the displaced atoms from the walls are injected into the tubes and migrate in the axial direction. After cutting, the tube ends close, and interstitial atoms become trapped in the hollow core (see picture).…
A simple, one-step method has been utilized to synthesize functional ternary alkali titanate nanowires of single crystallinity. Nanostructural characterization shows that the nanowires are Na2Ti6O13 with [010] growth direction and KTi8O16.5 with [001] growth direction.
The evolution of the iron catalyst during carbon single-walled nanotube growth is studied using calorimetry, temperature-programmed oxidation and Raman measurements. Carbon-induced solid-liquid, and solid-liquid-solid phase transitions of the nanocatalyst during the synthesis were observed. We found that liquid phase…
The adsorption and separation of linear $({\mathrm{C}}_{1}\text{\ensuremath{-}}n{\mathrm{C}}_{5})$ and branched (${\mathrm{C}}_{5}$ isomers) alkanes on single-walled carbon nanotube bundles at 300 K have been studied using configurational-bias Monte Carlo simulation. For pure linear alkanes, the limiting adsorption pr…
The inhibition of calcite precipitation by natural organic material (NOM) in solutions seeded with calcite was investigated using a pH-stat system. Experiments were carried out using three NOMs with different physical/chemical properties. For each of the materials, inhibition was found to be more effective at lower ca…
Thermoresponsive and injectable semi-interpenetrating polymer networks (sIPNs) containing a biospecific cell-adhesive signal and proteolytically degradable domains were developed as a synthetic equivalent of the extracellular matrix (ECM). The sIPNs synthesized define a modular hydrogel ECM where different properties…
Based on the previously suggested model of nanoscale dislocations induced Josephson junctions and their arrays, we study the magnetic field induced electric polarization effects in intrinsically granular superconductors. In addition to a new phenomenon of chemomagnetoelectricity, the model predicts also a few other in…
We present a plane wave/pseudopotential implementation of the method to calculate electron transport properties of nanostructures. The conductance is calculated via the Landauer formula within formalism of Green's functions. Nonorthogonal Wannier-type atomic orbitals are obtained by the sequential unitary rotations of…
We present an ab initio study of the structural and electronic properties of styrene molecules adsorbed on the dimerized Si(100) surface at different coverages, ranging from the single-molecule to the full monolayer. The adsorption mechanism primarily involves the vinyl group via a [2+2] cycloaddition process that lea…
Nanotechnology has the potential to dramatically improve the effectiveness of a number of existing consumer and industrial products and could have a substantial impact on the development of new products ranging from disease diagnosis and treatment to environmental remediation. The broad range of possible nanotechnolog…
Pyrochlore dielectric materials such as (Bi$_{1.5}$Zn$_{0.5}$)(Nb$_{1.5}$Zn$_{0.5}$)O$_7$ (BZN) have generated interest because they combine high dielectric constants with small dielectric loss tangents and yet are cubic at all temperatures. The recent low-temperature preparation and structural characterization of Bi$…
The formation of regular precipitate stripes in the wake of moving chemical reaction-diffusion fronts is investigated. Experiments on the $NaOH+CuCl_2$ reaction in PVA hydrogel yield stripes parallel or slightly oblique to the front that supplies the precursor of the precipitate. The pattern formation was modeled by p…
We present time-dependent dielectric loss data for various glass formers below the glass temperature. The observed aging dynamics is described using a modified Kohlrausch-Williams-Watts law taking into account the variation of the relaxation time during aging. It leads to values for the aging relaxation time and stret…