Materials Literature
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Fast computer algorithms for calculating the reflection coefficients of inhomogeneous films are developed. The applications of such algorithms are aimed at real-time monitoring and control of the growth of gradient index optical coatings. Inhomogeneous films with a refractive index varying along the direction normal t…
A novel design for a large bending actuator is presented for the first time. It is composed of three components: an inner flexible beam or strip, a nickel - titanium shape memory alloy (SMA) contractile wire, and an outer soft plastic tube. The SMA wire is embedded between the beam and the plastic tube, and connected…
Porous GaAs layers have been produced by anodic etching of (100)-oriented crystalline substrates in a solution. Scanning electron microscope images showed the formation of submicron pores, the average dimension of the remaining GaAs walls being of about 100 nm. Raman scattering by LO-phonon - plasmon coupled modes, in…
Abstract While the colorless form of the propyl-substituted, binaphthol-condensed indolylfulgide did not emit fluorescence, its colored form, generated by the UV-light irradiation, emitted fluorescence in toluene at room temperature. Thus, a perfect on/off switching system of fluorescence controlled by the photochromi…
Local density functional (LDF) and ab initio Hartree-Fock (HF) calculations are reported for free base porphyrin, chlorin, bacteriochlorin, and isobacteriochlorin. The LDF optimized geometries provide a detailed picture of the structural effects of peripheral hydrogenation on the C α −C β and C β −C β bond distances,…
The nucleation and growth of recrystallized grains or pearlite colonies can be viewed as a structural phase transition and modeled with a set of phase-field equations. Such a micromechanical formulation is consistent with the viewpoint taken in deriving the Johnson-Mehl-Avrami-Kologoromov (JMAK) equation and delivers…
A new program is presented for the data analysis of XAFS. Comprehensive methods are available for the analysis of disordered systems.
μ-Carbido diporphyrinates and diphthalocyaninates of general formula [{ Mp 2− } 2 (μ- C )] ( p 2− = tpp ( M = Fe ), oep ( Fe ), pc ( Fe , Ru ); H 2 tpp : 21H,23H-5,10,15,20-tetraphenylporphine; H 2 oep : 21H,23H-2,3,4,8,12,13,17,18-octaethylporphine; H 2 pc : 29H,31H-phthalocyanine) of formally Fe IV and Ru IV are pre…
In situ diffuse reflectance spectra of supported chromium oxide catalysts are investigated for the first time at elevated temperatures under controlled reaction conditions using a specially designed diffuse reflection attachment. The obtained results are compared and discussed with those obtained by the classical diff…
Bridged dithienylethylenes (DTEs) bearing solubilizing alkyl chains at various positions (2-5) have been synthesized by McMurry dimerization of cyclopenta[b]thiophen-6-ones. In order to introduce alkyl substituents at different positions of the DTE molecule, the precursor ketones have been prepared by different strate…
We introduce a notion of equivalence on tilings which is formulated in terms of their local structure. We compare it with the known concept of locally deriving one tiling from another and show that two tilings of finite type are topologically equivalent whenever their associated groupoids are isomorphic.
An analytic solution for the kinetics of nonlinear (upconversion) luminescence quenching in solid-state laser materials and other luminophosphors is obtained under the assumptions of hopping character of migration-assisted energy transfer and finite excitation lifetime. It is shown how the observables of the luminesce…
Soft condensed matter physics is the study of materials, such as fluids, liquid crystals, polymers, colloids and emulsions, that are “soft” to the touch. This article will review some properties, such as the dominance of entropy, that are unique to soft materials and some properties such as the interplay between broke…
Dislocations in {1012} twin boundaries in Zn were investigated using high-resolution electron microscopy. The topological parameters (Burgers vectors and step heights) of several defects have been identified and found to be in excellent agreement with theoretical predictions. The core structures of all defects studied…
The advantage of Raman spectroscopy is that it can be used to identify structure. In this work, Raman spectra of CaC 2 O 4 ·H 2 O, a calibration standard for thermogravimetric analysis/differential thermal analysis (TGA/DTA), were taken or monitored continuously in a thermal process from 25 to 750 °C with a heating ra…
(2,3,7,8,12,13,17,18-Octamethylcorrolato)manganese(III), [Mn(OMC)], has been characterized by several physical measurements. In the presence of nitrogenous bases the complex exists as a valence tautomer [Mn(II)(OMC(*+))] as demonstrated by (1)H NMR and EPR. Complete resonance assignment in the NMR spectrum has been ac…
Line-profile simulation and matching on the basis of a paracrystalline one-dimensional Hosemann model provides a promising approach to the analysis of line broadening. Results of analysis using X-ray wide-angle data of polymers and metallic samples are compared with Warren–Averbach multiple-order and single-order meth…
A systematic study of the electronic structure of models for the active sites of heme enzymes such as peroxidases and cytochromes P450 has been carried out for high-valent transition states of their catalytic cycles, namely, compound I and compound II for peroxidases, as a function of the second axial ligand. The inve…
Calculations of the ambient dose equivalent conversion factors for neutron energies from 20 MeV to 5 GeV have been performed using the Monte Carlo high energy transport code HADRON. The kerma approximation extended to the high energy region was applied in the calculations. The results obtained are compared with the pr…
We report on light-induced nonpolar orientation of sidechain nonlinear-optical polyimides [glass transition temperatures (Tg) up to 350 °C] containing no flexible connectors or tethers. The nonlinear-optical azo-dye chromophore is incorporated through the donor substituent as a part of the polymer backbone. This impre…