Materials Literature
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A detailed theory of nonisothermal electron transport perpendicular to multilayer superlattice structures is presented. The current–voltage (I–V) characteristics and the cooling power density are calculated using Fermi–Dirac statistics, density-of-states for a finite quantum well and the quantum mechanical reflection…
In this letter we report on the low-temperature specific heat of several M2AX phases: Ti2AlC, V2AlC, V2AsC, Nb2SnC, Ti2AlN, Hf2InC, Nb2AlC, and Cr2AlC. The Debye temperatures are quite high. The density of states at the Fermi level, N(EF) varies from ≈1.4 (eV formula unit)−1 to 6 (eV formula unit)−1. Ab initio calcula…
Al 2 O 3 doped Ba0.5Sr0.5TiO3 (BST) thin films, with different Al2O3 contents, were deposited on (100) LaAlO3 substrates by the pulsed laser deposition technique to develop agile thin films for tunable microwave device applications. The dielectric properties of Al2O3 doped BST films were determined with a nondestructi…
The dielectric properties of Ba0.8Sr0.2TiO3 ceramics doped with Mg from 0.5 to 10 mol % have been investigated systematically. Two effects of Mg doping on the dielectric properties of the Ba0.8Sr0.2TiO3 ceramics have been observed. At low Mg doping concentrations (<2 mol %), Mg mainly acts as an acceptor dopant…
The temperature dependence of the effective transverse piezoelectric coefficient (e31,f) in lead zirconate titanate (PZT) thin films was measured between −55 and 85 °C. e31,f was calculated by simultaneously monitoring the piezoelectric charge output and strain in the film during wafer flexure. This method was used to…
Magnetomechanical experiments were performed with a ferromagnetic Ni–Mn–Ga single crystal consisting of thermoelastic orthorhombic martensitic phase at room temperature. The crystal was deformed in uniaxial compression along 〈100〉 with an orthogonal magnetic field and without a magnetic field. The sample deforms due t…
Crystallization of amorphous Ge2Sb2Te5 films (10, 40, and 70 nm thick) was studied by in situ heating in a transmission electron microscope (TEM). Electron irradiation-induced crystallization is possible at room temperature using a 400 kV electron beam where the reciprocal of the incubation time for crystallization sc…
Hard-particle packings have provided a rich source of outstanding theoretical problems and served as useful starting points to model the structure of granular media, liquids, living cells, glasses, and random media. The nature of “jammed” hard-particle packings is a current subject of keen interest. Elsewhere, we intr…
The extended Cauchy equations are derived based on the Vuks equation for describing the wavelength- and temperature-dependent refractive indices of liquid crystal compounds and mixtures. This model fits experimental data well in the off-resonance spectral region. Correlations between the Cauchy coefficients for the ne…
Magnetic nanoparticles embedded in polymer matrices have excellent potential for electromagnetic device applications like electromagnetic interference suppression. We have synthesized polymer nanocomposites of poly(methylmethacrylate) doped with varying concentrations of iron nanoparticles (∼20 nm in size). The iron n…
The N–In codoped p-type ZnO films have been prepared by ultrasonic spray pyrolysis. X-ray photoelectron spectroscopy analysis confirmed the presence of nitrogen and indium in the codoped films, and the incorporation of indium causes the change in the chemical state of nitrogen, which promotes the formation of p-type c…
The grain-size effect on deformation twinning in nanocrystalline copper is studied. It has been reported that deformation twinning in coarse-grained copper occurs only under high strain rate and/or low-temperature conditions. Furthermore, reducing grain sizes has been shown to suppress deformation twinning. Here, we s…
The mechanism of ultraviolet (UV) and green emission of ZnO thin films deposited on (001) sapphire substrates by pulsed laser deposition was investigated by using postannealing treatment at various annealing temperatures after deposition. Structural, electrical, and optical properties of ZnO films have been also obser…
Thin and flexible composite films of raw or purified multiwalled carbon nanotube (MWCNT) with various mass fractions and poly(methylmethacrylate) (PMMA) were synthesized for electromagnetic interference (EMI) shielding material. From scanning electron microscopy and high-resolution transmission electron microscopy pho…
4-Hydroxybenzoyl-CoA reductase (4-HBCR) is a central enzyme in the metabolism of phenolic compounds in anaerobic bacteria. The enzyme catalyzes the reductive removal of the phenolic hydroxyl group from 4-hydroxybenzoyl-CoA, yielding benzoyl-CoA and water. 4-HBCR belongs to the xanthine oxidase (XO) family of molybdenu…
Diaminopimelate (DAP) epimerase (DapF) is central to the biosynthesis of both lysine and cell-wall peptidoglycan in many bacteria species. The peptidoglycan layer provides great potential for the development of novel antimicrobials as it is a uniquely prokaryotic feature. Crystals of recombinant Haemophilus influenzae…
Electroactive polymer (EAP) transducers are an emerging technology with many features that are desirable for MEMS devices. These advantages include simple fabrication in a variety of size scales, and ruggedness due to their inherent flexibility. Dielectric elastomer, a type of EAP transducer that couples the deformati…
In the last decade, high-resolution data have become available for macromolecular objects. Furthermore, ultrahigh-resolution diffraction data (resolution close to 0.6 A) have been collected for several protein crystals. This allows the study of fine details of the electron-density distribution such as the deformation…
A small cysteine-rich protein, the function of which remains elusive, was discovered in the exudate of a Penicillium species. Crystal diffraction experiments conducted using in-house Cu Kalpha radiation and an R-AXIS IV++ imaging-plate detector yielded high-quality data to 1.4 A, with a distinguishable anomalous signa…
Spiropyrans undergo reversible photoisomerization between their ring-closed (spiro) and ring-open (merocyanine) forms when exposed alternately to ultraviolet and visible light. Rates of K + ion leakage from phosphatidylcholine unilamellar vesicles containing a K + -selective crown ether attached to an amphiphilic spir…