Materials Literature
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We discuss polymer brushes containing a small fraction of minority chains that differ from the majority brush-forming chains both in length and in chemical structure. We consider the situation that the solvent is good for both types of chain. Furthermore, we assume that the minority chains are longer than the brush ch…
Molecular-dynamics simulations were performed, by using a phenomenological potential model, which takes into account steric repulsion due to atomic sizes, screened Coulomb interaction from charge transfer, charge-dipole interaction due to the large electronic polarizability of the anions, and dipole-dipole interaction…
The possible domain patterns are developed for (111) oriented epitaxial tetragonal ferroelectric (FT) films. The domain patterns in the film form as the result of phase transition from the paraelectric to ferroelectric state to minimize the elastic energy of the system at the expense of creating of domain boundaries a…
We extend our earlier study of nanoscale pattern formation during electropolishing [Nanotechnology 7, 360 (1996); Phys. Rev. B 56, 12 608 (1997)]. The patterns are attributed to preferential adsorption of organic molecules on the convex portion of the electrode due to its enhanced electric field. This local enhancemen…
All-ceramic crowns are coming into widespread use because of their superior esthetics and chemical inertness. This study examines the hypothesis that glass-infiltrated alumina and spinel core ceramics are resistant to damage accumulation and strength degradation under representative oral contact conditions. Accordingl…
The behavior of 1018 steel, 6061-T6 aluminum, and titanium 6%Al–4%V alloy during a dynamic punch test is investigated. Specifically, the possibility and affects of adiabatic shear localization are examined. The three materials are chosen to encompass a wide range of physical properties. Punch tests are conducted at av…
PACVD has been used to obtain SiBCN thin films for the first time at low temperatures (250 °C) from a single-source precursor. In comparison with PACVD BCN, the B:C ratio is the same, but there is a slightly increased N content, and the presence of Si improves the hardness and adhesion characteristics. XPS and FTIR re…
Escherichia coli glycerol kinase (GK) displays "half-of-the-sites" reactivity toward ATP and allosteric regulation by fructose 1, 6-bisphosphate (FBP), which has been shown to promote dimer-tetramer assembly and to inhibit only tetramers. To probe the role of tetramer assembly, a mutation (Ser58-->Trp) was designed to…
We have investigated the Raman spectra of thermally and laser annealed Ge 2 Sb 2 Te 5 films. The thermally crystallized film included few amorphous Te–Te bonds, however a large number of the Te–Te bonds remained in the laser annealed film. It was suggested that the Te–Te amorphous bonds were one of the main reasons le…
We present a revised estimate of the relaxation time at room temperature for a window glass based on extrapolated isostructural viscosity data. This estimate, while several orders of magnitude less than the previous estimate of Zanotto [Am. J. Phys. 66 (5), 392–395 (1998)], supports his conclusion that window glass ca…
A pure culture of a common colonial freshwater picoplanktonic chlorophyte, Pseudodictyosphaerium jurisii, was isolated from Lake Stechlin (Brandenburg, Germany). This strain was compared with solitary picochlorophytes with respect to morphology, ultrastructure, and the biochemical composition of the cell walls. Its ph…
A microscopic gas‐sensing model for ethanol sensors based on polypyrrole‐poly(ethylene oxide) (PPy‐PEO) composite films prepared electrochemically is proposed. Based on this model, a sensing equation was developed which indicates the dependence of sensitivity of gas sensors on the site number of a monolayer, the thick…
Photochemical reduction of silver(I) to silver nanoparticles was achieved, for the first time, in aqueous Triton X-100 medium using ascorbic acid. The particles show the usual plasmon absorption band of silver at 410 nm and a new band at 650 nm. Transmission electron microscope studies show that the size of the indivi…
Abstract Textural, mineralogical and chemical parameters of clays belonging to the Upper Cretaceous ‘Argilas de Aveiro’ formation were determined and correlated, using geostatistical analysis, with some relevant geotechnical parameters. The data obtained made it possible to subdivide the region under study into distin…
We investigated the role of receptor binding affinity in surface adhesion. A sensitive technique was developed to measure the surface energy of receptor-mediated adhesion. The experimental system involved a functionalized elastic agarose bead resting on a functionalized glass coverslip. Attractive intersurface forces…
Thermal shock behavior of a variety of open‐cell ceramic foams was evaluated using infrared heating and forced air cooling. The extent of damage after thermal shock was determined by a nondestructive, dynamic resonance technique. The damage in foams was found to be strongly dependent on cell size and weakly dependent…
Dense nanograined SiC ceramics were obtained by using hot isostatic pressing (HIP). The starting powder was ultrafine β‐SiC powder, which had a mean particle size of 30 nm and contained 3.5 wt% free carbon. SiC powders‐both boron‐doped and undoped‐were densified via HIP under an ultrahigh pressure of 980 MPa at a temp…
Gelcasting is a promising new technology for manufactur‐ing advanced structural ceramic components. The process involves drying of the “green” gelcast part before densifi‐cation. The physical mechanisms that control this relatively long drying process are not well understood. In this study, several controlled experime…
The ac complex conductivity σ*(f) of polyaniline (PAN) films at different doping levels and different temperatures, in the 1–100 KHz frequency range, are reported. The results are typical of a disordered medium where the real component of ac conductivity is frequency independent at low frequencies, rising for higher v…
Summary Data from two Podzol O and E horizons, sampled in 1‐cm layers at 13 points within 2 m × 2 m plots, were used to test the hypothesis that the composition of hydrogen ions (H) and aluminium (Al) adsorbed to the solid‐phase soil organic matter (SOM) determines pH and Al solubility in organic‐rich acidic forest so…