Materials Literature
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The electronic states and optical transition properties of silicon quantum-well layers embedded by ${\mathrm{SiO}}_{2}$ layers are studied by the empirical pseudopotential homojunction model. The energy bands, wave functions, and the optical transition matrix elements are obtained for layers of thickness from 1 to 6 n…
The structure of has been investigated by high-temperature neutron diffraction and molecular dynamics simulation. It was found that the apparent Mg - F bond contraction reported in previous work arises from large anisotropy in the distribution of ions. The cell parameter in the cubic phase is approximately 2% less tha…
Barium titanate powders were produced using either an amorphous hydrous Ti gel or anatase precursor in a barium hydroxide (Ba(OH) 2 ) solution via a hydrothermal technique in order to discern the nucleation and formation mechanisms of BaTiO 3 as a function of Ti precursor characteristics. Isothermal reaction of the am…
The sound velocity v s ( T ) and the electrical resistivity ρ( T ) of La 1- X Sr X MnO 3 (0.11≤ X ≤0.17) have been measured and anomalies in v s ( T ), which are related to the polaron-ordered phase centered at X =1/8, have been observed. The phase diagram between the polaron-ordering temperature T P and X has been de…
The ferroelastic and antiferroelectric transition (between phases called P and R) in samples, pure and doped with Mn (0 - 3.3 mol%), was investigated. The phase diagram was obtained from DTA tests. The doping resulted in lowering of the P - R phase transition temperature. The shift of the P - R phase transition temper…
Neutron diffraction was used to determine the crystallographic structures of the ${\mathrm{YFe}}_{10}{\mathrm{Mo}}_{2}$ and ${\mathrm{YFe}}_{10}{\mathrm{Mo}}_{2}X$ $(X$=H,N). The spin-polarized muffin-tin-orbital method was applied to calculate the electronic structures of ${\mathrm{YFe}}_{10}{\mathrm{Mo}}_{2}X$ $(X$=…
The electronic “umpolung” of the title compound 1 to the dianion 2 is achieved by the uptake of four electrons from potassium in THF. Although the ring skeleton of the 18π 1 deviates significantly from planarity because of the streric requirements of the four selenium atoms, the new macrocycle fulfils the NMR criteria…
We report low voltage (1.5–3 V) performance of ferroelectric Pb(Zr,Ti)O3 based capacitors. La substitution up to 10% was performed to systematically lower the coercive and saturation voltages of epitaxial ferroelectric capacitors grown on Si using a (Ti0.9Al0.1)N/Pt conducting barrier composite. Ferroelectric capacito…
One-photon and two-photon photoelectron emission (1PPE/2PPE) spectroscopy is used to study surface states at and below the Fermi energy on Ni(111) in $\overline{\ensuremath{\Gamma}}\ensuremath{\rightarrow}\overline{K}$ and $\overline{\ensuremath{\Gamma}}\ensuremath{\rightarrow}\overline{M}$ direction. Picosecond UV la…
Sm 10 Fe 90−x Ti x alloys (x=0, 1, 3, 4, 5, 6, 8, 10) were prepared by rapid quenching and sequent annealing. Structural transformations from amorphous, metastable-to-equilibrium phases, and magnetic properties of their nitrides were systematically investigated. A CaCu5-type metastable phase was formed for 0⩽x⩽10 as t…
We present a novel principle for a fast bistable nematic display with intrinsic grey scale. The geometry of a single pixel is the usual hybrid texture in between two conductive flat plates. The device is written by creating surface walls when an electric field is applied, above the thresholds to achieve both the plana…
In this paper, a simplified model was used to describe the interactions between the enantiomers in a scalemic mixture. Monte Carlo simulations were performed to determine several thermodynamic properties as a function of temperature and mole fraction of solid, liquid, and gas phase. Phase diagrams were constructed usi…
Diamond films were grown by microwave plasma chemical vapor deposition on as-received platinum (Pt) foils, specially processed Pt foils with (111) domains, bulk single-crystal Pt with a (111) surface, and single-crystal Pt(111) films deposited on strontium titanate (111). In all cases, the substrate surfaces had been…
The microporous structure of artificial vascular grafts, which increases compliance and porosity simultaneously, may enhance neoarterial regeneration. In order to differentiate these effects, three models of segmented polyurethane grafts (inner diameter, 1.5 mm; wall thickness, 100 microns) with or without micropores…
Optical absorption and emission properties of Er3+ ions in ZnCl2-based glasses are investigated. The electric dipole line strengths for various transitions were estimated from the measured optical absorption spectra. The spontaneous emission probabilities for various transitions were predicted using the Judd–Ofelt the…
Nanosize neutral silicon clusters produced using a laser vaporization source were analyzed in the gas phase and deposited on various substrates at room temperature in ultrahigh vacuum. Nanostructured thin films with thickness around 100 nm resulting from this nearly ballistic deposition process were subsequently chara…
Behavior as single-molecule gates for certain ions is demonstrated by dendrimers confined on surfaces and within thiol monolayers (see picture). The permeability depends on the chemical state of the dendrimer and the charge on the ion. These composite structures are models of biological membranes in that mass transfer…
A systematic study of the desorption behavior of Sb multilayers applied as a passivant to (001) GaAs is presented. Reflection high-energy electron diffraction, reflectivity, Auger electron spectroscopy, x-ray photoelectron spectroscopy, and thermal desorption data reveal unique and complementary information which can…
Plasma-enhanced chemical vapor deposition has been used for the deposition of diamond and diamond-like thin films during the last decade with great success. Here we present experimental evidence that a chemical vapor deposition technique can also be used to synthesize other forms of carbon including fullerenes and hyd…
Redox transmetallation ofTl(C5H4PPh2)with an excess of Sm in refluxing thf (thf = tetrahydrofuran) or Eu indme (dme = 1,2-dimethoxyethane) at room temperature gave thelanthanoid(II) compounds[Sm(C5H4PPh2)2](1) and[Eu(C5H4PPh2)2(dme)](2). Crystallization of (1) or[Yb(C5H4PPh2)2(dme)]with OPPh3 in dme yielded[Sm(C5H4PPh…