Materials Literature
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Etching of Si in a variety of solutions is known to cause staining. These stain layers consist of porous material similar to that produced by anodic etching of Si in HF solutions. We have observed photoluminescence peaked in the red from stain-etched Si wafers of different dopant types, concentrations, and orientation…
We report experimental results describing the mechanical breakdown of random porous Au which is a new material specifically developed for this study. Digital image analysis was used to characterize the microstructures of the samples which varied by more than 2 orders of magnitude in length scale. The porous Au undergo…
A modified version of the random sequential adsorption model for the deposition of spherical particles onto a plane is presented. Successive particles are added via randomly positioned vertical trajectories and, if they do not stick to the plane at first contact, follow the path of steepest descent on the previously d…
Nonequilibrium states of surface composition can be extremely long-lived when polymer chains adsorb competitively. In a model system (polymethylmethacrylate adsorbed from CCl(4) onto oxidized silicon previously saturated with polystyrene), it is shown that a weakly adsorbing polymer was sterically pinned to a surface…
Molecular dynamics simulations are usually performed with a fixed number of particles in a periodic box of constant size and shape, however, there are situations in which it is desirable to carry out simulations, where the volume of the periodic box is allowed to fluctuate and the external pressure is fixed. The exter…
The amino acid sequence of mouse dihydrofolate reductase was permuted circularly at the level of the gene. By transposing the 3'-terminal half of the coding sequence to its 5' terminus, the naturally adjacent amino and carboxyl termini of the native protein were fused, and one of the flexible peptide loops at the prot…
Abstract Drill pipe operations inside casing produces a crescent-shaped wear pattern. Such wear can compromise the design integrity of the casing string. The lack of an adequate method of calculating the rupture pressure of crescent-shaped wear casing prevents an accurate assessment of the true safety factor of the st…
For three different murine immunoglobulins (IgG subclasses 1, 2a, and 2b), the distances between their antigen-binding sites have been measured using neutron scattering from deuterated antigens complexed with proteated IgG. Neutron-scattering data were measured for each antibody-antigen complex in a 41% D2O solvent. U…
We report the first measurements of the optical functions of polycrystalline metal films throughout nucleation and growth. The dielectric function of aluminum, evaporated onto ${\mathrm{SiO}}_{2}$, was determined versus thickness d by real-time multichannel ellipsometry (1.3\ensuremath{\le}h\ensuremath{\nu}\ensuremath…
We consider the inclusive reaction pp\ensuremath{\rightarrow}\ensuremath{\Lambda}X in the fragmentation region and present a dynamical mechanism which leads to a fair description of all the basic features of the observed \ensuremath{\Lambda} spectrum. We also show in a simple manner why it generates a nonzero \ensurem…
Cleaved GaAs surfaces decompose under weak pulsed-laser irradiation, leading to the formation of metallic Ga islands. The reduction of band bending nonuniformities in photoemission spectra acquired during the laser pulses, in concert with new core-level fitting techniques which treat broadened spectra, permits a detai…
Electrochromic properties of the V2O5 thin films prepared from a spinnable organic vanadium solution were investigated. The films heat-treated at 400 °C showed clear two-step electrochromism, deep blue⇄green⇄yellow, with its response time for obtaining ΔOD=0.5 being ∼2 s. The yellow and green colors showed good memory…
The dielectric constant (\documentclass{article}\pagestyle{empty}\begin{document}$ \varepsilon ' $\end{document}) and dielectric loss tangent (tan δ) of mixed Li-Cd ferrites of various compositions are measured at room temperature in the frequency range 1 to 100 kHz using a capacitance bridge. Plots of dielectric cons…
Effects connected with elastic fields of straight edge dislocations in a thin two-phase plate with different moduli are studied. It has been established that interaction of the dislocation with point defects leads to impurity-vacancy polarization of the plate when impurities and vacancies do not only form the Cottrell…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAtomic-Scale Imaging of Materials by Z-Contrast Scanning Transmission Electron MicroscopyS. J. PennycookCite this: Anal. Chem. 1992, 64, 4, 263A–272APublication Date (Print):February 15, 1992Publication History Published online31 May 2012Published inissue 15 February 1992htt…
The effective thermal conductivity of binary dispersed composites prepared from mixed and compacted powders of NaCl and low-density polyethylene (LDPE) was measured over the entire range of volume fraction at temperatures in the range 120–320 K together with pressures up to 1.73 GPa. Measurements were made using the t…
The desorption of As from GaAs (001), (111)B, and AlAs(001) is studied in detail by measuring the electron-beam current reflected from these surfaces. When the As supply to the surface was terminated, the electron specular reflectivity decreases exponentially with time due to the As desorption. The decay rate was much…
Abstract Direct current (dc) and alternating current (ac) electrical properties of semicrystalline poly(butylene terephthalate) (PBT) are investigated as a function of temperature and frequency. Dc electrical conductivity measurements have been performed over the temperature range −75°C to 130°C and point out an essen…
Thulium (Tm) emissions were investigated in 390 keV, Tm-implanted AlGaAs, GaAs, InP, and Si using photoluminescence spectroscopy. The emissions in the different semiconductors were observed in the 1.20 to 1.35-μm region and are attributed to transitions between the crystal-field-split spin–orbit levels 3H5– 3H6 of Tm3…
Pressure dependence of the electrical conductivity of a range of polypyrrole samples doped to various levels is interpreted in terms of variable-range hopping theory. All samples are well described by a model that treats the density of localized states around the Fermi level as the pressure-dependent commodity. The pr…