Materials Literature
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Ab initio electron propagator calculations on tetracyanoquinodimethane (TCNQ) and tetracyanoethylene (TCNE) produce accurate predictions of vertical ionization energies and electron affinities. Plots of Feynman–Dyson amplitudes associated with each ionization process represent how the electron distribution changes fro…
The noise in the depth profiles of secondary ion mass spectrometry (SIMS) is studied using different samples under various experimental conditions. Despite the noise contributions from various parts of the dynamic SIMS process, its overall character agrees very well with the Poissonian rather than the Gaussian distrib…
Polarized neutron diffuse scattering studies made above and below the re-ordering temperature on an crystal have revealed a random atomic arrangement of Mn and Fe atoms. The magnetic disturbance produced by Mn atoms is confined to the substituted sites. There appears to be greater change in the moment difference betwe…
A soap film (made of two air/water interfaces covered by surfactant) may turn into a so-called Newton black film (NBF) which essentially consists in a surfactant bilayer. Oil-in-water emulsion droplets covered with surfactant (oil/water interfaces) may become adhesive in similar conditions. We show by analyzing the ne…
The structure factor of a poly(ethylene-propylene)-poly(dimethylsiloxane) diblock copolymer has been measured by small-angle neutron scattering as a function of temperature and pressure. The conformational compressibility exhibits a pronounced maximum at the order-disorder phase transition. The phase boundary shows an…
Tunneling spectroscopy studies on oxidized and bare surfaces of icosahedral i-AlPdRe, i-AlCuFe, and approximant $\ensuremath{\alpha}$-AlMnSi phases reveal specific features of the density of states (DOS) close to the Fermi level as compared to the crystalline nonapproximant $\ensuremath{\omega}$-AlCuFe phase. The Ferm…
We report the first observation of the vibrational Raman spectrum of hydrogen molecules ${\mathrm{H}}_{2}$ in crystalline silicon treated with hydrogen atoms at 400 \ifmmode^\circ\else\textdegree\fi{}C. The Raman spectrum of ${\mathrm{H}}_{2}$ in silicon observed at room temperature exhibits a frequency shift of aroun…
Isothermal electron beam heating combined with in situ optical measurements has been used to measure the temperature dependence of the spectral emissivity of lightly doped silicon in the range 345–723 °C for wavelengths between 1 and 9 μm. The absorption coefficient was deduced from the spectral emissivity and compare…
Scanning electron microscopy micrographs of n-type silicon carbide (SiC) anodized in HF solution showed a highly porous layer having structures with dimensions of about 50 nm. The capacitance of the porous electrodes revealed a huge surface area. The photocurrent quantum yield of a porous SiC/electrolyte diode is spec…
Zn in GaN forms an efficient radiative center and acts as a deep acceptor which can make the crystal insulating. Four different Zn-related centers have been by now identified, leading to light emission in the range between 1.8 eV and 2.9 eV. We present a first-principles investigation total energy and electronic struc…
The formation energy of a solid surface can be extracted from slab calculations if the bulk energy per atom is known. It has been pointed out previously that the resulting surface energy will diverge with slab thickness if the bulk energy is in error, in the context of calculations which used different methods to stud…
Impurity levels and formation energies of acceptors in wurtzite GaN are predicted ab initio. Be_Ga is found to be the shallow (thermal ionization energy $\sim$ 0.06 eV); $Mg_{Ga}$ and $Zn_{Ga}$ are mid-deep acceptors (0.23 eV and 0.33 eV respectively); $Ca_{Ga}$ and $Cd_{Ga}$ are deep acceptors ($\sim$0.65 eV); $Si_N$…
The traditional magnetic storage mechanisms (both analog and digital) apply an external field signal H(t) to a hysteretic magnetic material, and read the remanent magnetization M(t), which is (roughly) proportional to H(t). We propose a new analog method of recovering the signal from the magnetic material, making use…
A novel procedure for calculating magnetic susceptibilities and nuclear magnetic shieldings in molecules is outlined, based on formal annihilation of transverse paramagnetic contribution to quantum mechanical current density induced within the electron cloud by an external homogeneous, static magnetic field. Within th…
This article describes the synthesis of biodegradable polyphosphazenes. The rate of degradation can be varied in a controllable manner by the introduction of hydrolysis-sensitive amino acid ester side groups or by blending of polymers. Biodegradable polyphosphazenes can be used for the preparation of drug-containing i…
Microporous polypropylene fibers were prepared by stretching polypropylene fibers containing CaCO3 filler. The properties of the resultant fibers are controllable by adjusting the filler content and the stretching ratio. Also, it is elucidated that the fibers have a fine texture of polypropylene fibrils, in which the…
This paper describes a vision-based system that monitors the yarn density of woven fabrics on-line. The system is described in terms of its two principal modules, namely, the image acquisition and the image analysis subsystems. The image acquisition subsystem is implemented with standard components on a low-cost perso…
In this article, two kinds of perfluoropolyether (PFPE) with different terminal groups were investigated using thermogravimetric analysis (TGA), infrared (IR) spectroscopy, gel permeation chromatography (GPC), and gas chromatography/gas mass spectrum (GC/MS) analysis. PFPEs with a hydroxyl or carboxylic acid terminal…
The morphology of the microcellular ethylene–propylene–diene terpolymer (EPDM) vulcanizes of both an unfilled and filled compound was studied from SEM photomicrographs. Carbon blacks adversely affect the average cell size, maximum cell size, and cell density. Enclosed gas pressure in a closed cell increases the relati…
Low-density polyethylene/ethylene–vinyl acetate copolymer (LDPE/EVA) blend was irradiated by γ-ray and then expanded by heat as a foamed material. The EVA content in the LDPE/EVA blend was benefited to form a gel. The gel fraction values of LDPE/EVA blend with 30% EVA content were higher than those of other blends in…