Materials Literature
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Low‐pressure cold welding has been used to fabricate 200 μm diameter organic light‐emitting devices (OLEDs) (see Figure). The contacts are made by transferring a metal film from a patterned, soft elastomeric stamp onto unpatterned organic and metal layers on a substrate. The process does not adversely affect the OLED…
The Raman scattering by phonons and magnons was studied for the first time in the polycrystalline solid solutions Ni c Mg 1− c O. The experimental Raman spectrum for c = 0.9 is similar to that of NiO and consists of six well resolved bands, whose origins are the disorder-induced one-phonon scattering (bands at 400 and…
The local arrangement of atoms surrounding a substitutional ${\mathrm{Cr}}^{3+}$ and ${\mathrm{Fe}}^{3+}$ ion in $\ensuremath{\alpha}$-${\mathrm{Al}}_{2}{\mathrm{O}}_{3}:$ ${\mathrm{Cr}}^{3+}$ (ruby) and in $\ensuremath{\alpha}$-${\mathrm{Al}}_{2}{\mathrm{O}}_{3}:(\mathrm{F}\mathrm{e}\ensuremath{-}\mathrm{T}\mathrm{i}…
Structural phase transitions in the Aurivillius phase ferroelectrics ${\mathrm{SrBi}}_{2}{\mathrm{Nb}}_{2}{\mathrm{O}}_{9}$ and ${\mathrm{Bi}}_{5}{\mathrm{Ti}}_{3}{\mathrm{FeO}}_{15},$ containing two and four perovskite layers, respectively, have been studied using powder neutron diffraction. At temperatures below the…
Three elastic phases of covalent networks, (I) floppy, (II) isostatically rigid, and (III) stressed-rigid, have now been identified in glasses at specific degrees of cross linking (or chemical composition) both in theory and experiments. Here we use size-increasing cluster combinatorics and constraint counting algorit…
The third‐order nonlinear optical property χ (3) I of a film of single‐walled carbon nanotubes was studied in the infrared region. The film combines a high χ (3) I (–0.85 × 10 –7 esu at resonant wavelength) with a rapid transmittance recovery (from differential transmission spectra, see Figure), making it suitable for…
For biomedical applications, zirconia‐toughened alumina ceramics (see Figure) would be very appropriate materials, provided that the zirconia content is kept below the percolation threshold (upper limit of 16 vol.‐% 3Y‐TZP inside an alumina matrix). That the concept of a percolation threshold is relevant when talking…
The formation of "zero" (exponentially small) resistance states (ESRS) in high mobility two-dimensional electron systems (2DES) in a static magnetic field B and subjected to strong microwave (MW) radiation has attracted great theoretical interest. These states appear to be associated with a new kind of energy gap $Δ$.…
We have studied the low-temperature behavior of the magnetization and the specific heat of the bilayered perovskite system $% La_{2-2x}Sr_{1+2x}Mn_{2}O_{7}$, for $0.30\leq x\leq 0.50$. Our analysis reveals that below 30 K the temperature dependence of the magnetization of the ferromagnetic samples, $x=0.30$, 0.32, and…
The recently reported Rutherford backscattering and particle-induced x-ray emission experiments have revealed that in low-temperature molecular beam epitaxy grown ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ a significant part of the incorporated Mn atoms occupies tetrahedral interstitial sites in th…
The magnetic circular dichroism (MCD) of core-level absorption (x-ray absorption spectroscopy, XAS) spectra in the soft x-ray region has been measured for the ferromagnetic Heusler alloy ${\mathrm{Co}}_{2}{\mathrm{Cr}}_{0.6}{\mathrm{Fe}}_{0.4}\mathrm{Al}$ at the Co, Fe, and Cr ${L}_{II,III}$ edges. The comparison of X…
A phenomenological theory of the incommensurate phase transition in thin films is presented for the case of the single-component order parameter. The order parameter distribution over the film is obtained under the assumption of slowly-varying amplitude. The size effect on the temperature of the phase transition into…
A transition state theory based predictive model is developed for the tensile failure of carbon nanotubes (CNT's). We show that the tensile yield strain has linear dependence on the activation energy and the temperature, and has a logarithmic dependence on the strain rate. Based on the parameters fitted from strain ra…
PURPOSE: To investigate and compare the effect of three analytical methods, hydrogen bromide titrimetry (HBr titrimetry), infrared spectroscopy (IR spectroscopy), and first derivative UV-spectrophotometry (FDUV-spectrophotometry) in the determination of degree of deacetylation (DD) of chitosan. METHODS: Three differen…
The failure of individual multiwall carbon nanotubes during field emission and two-probe characterization was studied in a scanning electron microscope on emitters grown by chemical vapor deposition. The failures induced by high currents during two-probe measurements led to a sundering of the tube in or near its middl…
We use first-principles density functional theory to calculate the phonon frequencies, electron localization lengths, Born effective charges, dielectric response, and conventional electronic structures of the IV-VI chalcogenide series. The goals of our work are twofold: first, to determine the detailed chemical compos…
Multiple quantum well nanorods have been fabricated via heteroepitaxial growth of ZnO and ZnMgO (see Figure and also cover). Simple yet accurate thickness control allows the realization of nanosized well structures in individual nanorods that are tunable through the effects of quantum confinement. This approach should…
Substituted hexabenzocoronenes (HBCs) form films with supramolecularly ordered columnar stacks that are uniaxially oriented onto poly(tetrafluoroethylene) alignment layers (see Figure). In field‐effect transistor (FET) tests, mobilities of up to 10 –3 cm 2 V –1 s –1 and high on–off ratios of more than 10 4 were derive…
Ideally, rationally designed tissue engineering scaffolds promote natural wound healing and regeneration. Therefore, we sought to synthesize a biomimetic hydrogel specifically designed to promote tissue repair and chose hyaluronic acid (HA; also called hyaluronan) as our initial material. Hyaluronic acid is a naturall…
Abstract To assess corrosion in buried metallic pipelines that are coated and under cathodic protection, an algorithm is proposed. This algorithm that is called “Corrosion Assessment Algorithm” or briefly CAA, can be regarded as a modification of Frank & Morgan risk analysis. By using CAA, one can both calculate t…