Materials Literature
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In the work a macroscopic equation of yield stress of steel is showed. We have used a new thermo-elastic and thermo-visco-plastic material. The model takes into account the history of the material and a possibility of phase change in it to occur, with temperature-dependent material properties. An examplary to calculat…
Diffractive optical elements with blazed profiles can, in theory, have 100% relative efficiency. We review several methods for making such elements and compare their advantages and limitations. Our emphasis is on processes to produce elements other than those with approximate, stepped surfaces, such as binary optical…
Free convection in liquid metals is of significant practical interest to the crystal-growing community since the adverse effects of convective instabilities in the melt phase can be frozen into the solid product. Here, we present the results of a combined numerical and experimental study of steady convective flows in…
We demonstrate the fabrication of binary, multilevel, and blazed diffractive structures by a fast and flexible direct-write process by using an excimer-laser-based tabletop micromachining workstation with an integrated optical surface profiler.
High-fidelity diffractive surfaces have been generated with single-point diamond-turning techniques. A key to the success of this technique is the ability to shape the diamond tool tip to provide the optimum phase-relief profile, given manufacturing constraints. Replication technology is used to transfer the phase-rel…
A novel beam-steering device that makes use of a nematic liquid crystal (LC) is proposed and demonstrated. The beam-steering function is attained with a LC microlens with a divided hole-patterned electrode structure (DE-LC microlens). Optical properties of the DE-LC microlens are investigated and three-dimensional var…
An extension of the Kramers-Kronig method for treatment of polarized infrared reflectance spectra from the face of low-symmetry crystals, where directions of principal dielectric axes depend on frequency, is proposed. It is shown, how to obtain the frequency dependencies of the complex reflectivity tensor components,…
The phase separation process in mixtures containing two immiscible liquids and a surfactant was investigated in two dimensions by numerically integrating a time dependent Ginzburg–Landau model. The model free energy was constructed from two scalar and one vector order parameter fields. The scalar fields describe, resp…
The authors present an equivalent magnetic circuit for a solenoid linear variable differential transformer. Using magnetic circuit theory, the calculations for its magnetic circuit reluctance, mutual inductance, output voltage and sensitivity are provided. Experimental tests are used to verify the calculations.
A new yield function formalism is developed for isotropic materials. A spectrum of forms are inclusive to the general form that has two yield parameters. One parameter is that of a scale type involving uniform expansion or contraction of the yield function. The other is a non-dimensional shape parameter that controls…
Polycrystalline pyridinium perrhenate has been studied over a wide range of temperatures by differential thermal analysis, differential scanning calorimetry, proton NMR spectra and relaxation, and dielectric permittivity measurements. Two solid–solid phase transitions at 250 and 333 K have been revealed and the pyridi…
Dissipative particle dynamics (DPD), a new simulation technique appropriate at mesoscopic length scales, has been applied to a dilute solution of polymer in solvents of varying quality. Unlike earlier simulations, the solvent is represented in the form mobile particulate packets, so that potential interferences of sol…
Abstract : Ti-6Al-4V titanium alloy was subjected to three heat treatment conditions. Ballistic tests at ARL have shown differences in the ballistic performance, if annealed above the beta transus temperature. Mechanical tests under uniaxial compression as well as biaxial compression shear-stress states and high strai…
Scanning electron microscopes are considered the most likely tool for future CD metrology down to 0.1 micron linewidths and below. Charging effects on insulating materials are a long standing problem for electron microscopes. The shrinking design rules are making the measurement errors caused by charging more signific…
Rare-earth-doped thin films were made by plasma-enhanced chemical vapour deposition using a complex containing chelating ligands and tetraethoxysilane. By this means of deposition, the film was successfully doped with terbium or erbium and the luminescence properties were investigated. In the case of -doped films, str…
The effect of hydrogenation on the local order in amorphous germanium has been studied by EXAFS. Measurements have been carried out on sputtered a-Ge:H films with hydrogen concentrations of 0, 7, 10, and 15 at.%, as a function of temperature in the range 11 - 300 K. The first-shell EXAFS data were analysed by the rati…
A modelling approximation regarding the behaviour of electrons on metal surfaces with chemisorbed oxygen is presented. It is suggested that, as consequences of O - metal surface bonding, ionization, polarization and removal of metal atoms cause the non-uniformity in the surface potential barrier (SPB). The inelastic p…
The propeptide of subtilisin-family proteases is known to exhibit inhibitory activity toward a cognate protease in addition to its function as an intramolecular chaperone. For detailed investigation of its inhibitory properties, the propeptide of subtilisin BPN' was produced in Escherichia coli. Inhibitory activity me…
The nitrogenation of rare-earth--transition-metal compounds $({R}_{2}{M}_{17})$ more than doubles the Curie temperature $({T}_{C})$ of iron-rich compounds but lowers ${T}_{C}$ of cobalt-rich compounds. Self-consistent spin-polarized electronic-structure calculations are carried out to understand this unusual behavior…
Photostimulated luminescence phenomena have been observed in Ce3+-doped alkali borate glasses prepared under a reducing atmosphere. When the x-ray irradiated glasses were excited by a He–Ne laser (633 nm), photostimulated luminescence at about 360 nm due to the 5d–4f transition of Ce3+ ions was observed. The intensity…