Materials Literature
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The soft modes in the two- and eight-direction order-disorder ferroelectrics are calculated under the mean-field approximation. We find that the conventional method of the pseudospin model to calculate the soft-mode frequency is incorrect, and present a valid modified method. It is demonstrated that the conventional m…
Ultrananocrystalline diamond (UNCD) films 0.1–2.4 μm thick were conformally deposited on sharp single Si microtip emitters, using microwave CH4–Ar plasma-enhanced chemical vapor deposition in combination with a dielectrophoretic seeding process. Field-emission studies exhibited stable, extremely high (60–100 μA/tip) e…
PURPOSE: To establish a method for measuring the partition coefficient (lambda) of gadopentetate dimeglumine in humans in vivo, evaluate the spatial and intersubject variation in the lambda of normal myocardium, and compare these values on a regional basis with lambda values of acute and chronic infarcted myocardium.…
Abstract Polymeric materials include plastics, gels, synthetic fibres, and rubbers. They are all-important both in industry and in daily life. Unlike liquid water, ice, or sugar solution, polymers are not homogeneous. They are said to consist of two or more phases, and their production and processing, as well as their…
The electrical properties of two single‐phase, lanthanum‐doped BaTiO 3 compositions, x = 0.03 and x = 0.20, in Ba 1– x La x Ti 1– x /4 O 3 were investigated by impedance spectroscopy after heat treatment in oxygen, argon, and air at 1350°C. Samples heated in oxygen were electrically insulating, whereas those heated in…
Abstract 46 structure types of binary and ternary intermetallic compounds have been derived from the well known, simple aristotype AlB 2 . Many compounds with the general compositions RX 2 , RT 2 , RTX , and R 2 TX 3 (R = alkaline earth, rare earth or actinoid metal; T = transition metal; X = main group element) belon…
Photonic crystals can be thought of as optical analogues of semiconductors. Here recent advances in photonic crystals based on silicon are reviewed. After summarizing the theory of photonic bandgap materials, the preparation and linear optical properties of 1D, 2D, and 3D silicon-based photonic crystals are discussed.…
Abstract The influence of electron transport on the signal generation process in electron beam techniques is reviewed. A survey of the fundamental physical quantities for the electron–solid interaction is presented and sources for these quantities in the literature as well as semi‐empirical formulae are given. The the…
Highly luminescent CdTe nanocrystals were synthesized by reacting dimethylcadmium with different tellurium sources in mixtures of dodecylamine and trioctylphosphine as the coordinating and size-regulating solvent. Colloids of crystalline CdTe nanoparticles with zinc blende lattice displaying mean particle sizes betwee…
The geometry of metal-ligand interactions in proteins is examined and compared with information for small-molecule complexes from the Cambridge Structural Database (CSD). The paper deals with the metals Ca, Mg, Mn, Fe, Cu, Zn and with metal-donor atom distances, coordination numbers and extent of distortion from ideal…
Castable refractories containing calcium aluminate cement (CAC) are used ubiquitously in a range of furnace lining applications in the iron and steel, cement, glass, ceramic, and petrochemical industries. This review outlines their development from conventional high cement materials, through low cement and ultra-low c…
Layer-by-layer (LbL) assembly of oppositely charged polyelectrolytes was used to coat fluorescein particles. These particles, with a size of 4−9 μm, were prepared by precipitation of fluorescein at pH 2. Polystyrensulfonate (PSS) and polyallylamine (PAH) were used to form a polyelectrolyte shell on the fluorescein cor…
Stable hollow polyelectrolyte capsules were produced by means of the layer-by-layer assembling of poly(allylamine), PAH, and poly(styrenesulfonate), PSS, on melamine formaldehyde microcores followed by the core decomposition at low pH. These capsules are nonpermeable for urease in water and become permeable in a water…
In this paper, we explore the optical contributions of the substrate to the localized surface plasmon resonance (LSPR) spectrum of surface confined Ag nanoparticles produced by nanosphere lithography (NSL). We present optical extinction spectra of Ag nanoparticles fabricated on the following substrates: fused silica,…
A new infrared luminescence from bismuth-doped silica glass is discovered. Spectroscopic properties of this glass are different from those of previously reported Bi 2+ - or Bi 3+ -doped glasses or crystals. Its luminescence spectrum is wide (full-width at half maximum; about 200 nm), with the peak at 1140 nm with 500…
ATOMS is a user application providing crystallographic functionality useful to x-ray absorption spectroscopists. ATOMS is also a set of reusable, object-oriented software modules written in the Perl programming language providing crystallographic functionality and access to databases of absorption coefficients and ano…
Thermoelectric properties have been investigated for single crystals of ${\mathrm{Sr}}_{1\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{TiO}}_{3}$ for $0<~x<~0.1.$ We have found a large power factor (defined as $\mathrm{PF}{=S}^{2}/\ensuremath{\rho},$ S and $\ensuremath{\rho}$ being the Seebeck coefficient and resist…
A model for phonon heat conduction in a semiconductor nanowire with dimensions comparable to the phonon mean free path is developed. It is based on the solution of Boltzmann’s equation, which takes into account (i) modification of the acoustic phonon dispersion due to spatial confinement, and (ii) change in the nonequ…
The femtosecond optical response of noble metal nanoparticles and its connection to the ultrafast electron dynamics are discussed in light of the results of high-sensitivity femtosecond pump−probe experiments. The physical origins of the nonlinear responses in the vicinity of the surface plasmon resonance and interban…
Production of cellulose has been thought to be restricted to a few bacterial species such as the model organism Acetobacter xylinus. We show by enzymatic analysis and mass spectrometry that, besides thin aggregative fimbriae, the second component of the extracellular matrix of the multicellular morphotype (rdar) of Sa…