Materials Literature
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Abstract A procedure for synthesizing crystallization‐based separation processes is presented. In an evolutionary manner and without being restricted to a particular crystallization technique, flowsheet alternatives are generated to meet the separation objectives for a given system. This is achieved by recognizing the…
A large number of lead-free BaTiO3-based ceramics were prepared. Depending on the composition, some of them exhibit a relaxor behaviour whose characteristics were related to the type of ionic substitution and to the substitution rate. The relaxor effect is all the more favoured as the composition deviates more from Ba…
New well-defined macrodiols were prepared by ring-opening copolymerization of lactones and cyclic diesters with a low molecular weight diol. Suitable monomers are diglycolide, L,L-dilactide, ε-caprolactone, and rac-β-butyrolactone. With exception of rac-β-butyrolactone, the reaction can be performed with or without a…
We report on the fabrication of metal nanowires on an insulating substrate using carbon nanotubes as a new kind of mask material. By irradiating Ar+ ions of 300 eV energy on a nanotube-coated Au/Ti thin layer on a SiO2 substrate, Au/Ti nanowires were successfully formed just underneath the nanotube, indicating that th…
An electron-based technique for the imaging of crystal defect distribution such as material growth histories in non- and poorly conductive materials has been identified in the variable pressure or environmental scanning electron microscope. Variations in lattice coherence at the meso-scale can be imaged in suitable ma…
Carbon nitride CNx thin films were grown by unbalanced dc magnetron sputtering from a graphite target in a pure N2 discharge, and with the substrate temperature Ts kept between 100 and 550 °C. A solenoid coil positioned in the vicinity of the substrate was used to support the magnetic field of the magnetron, so that t…
The conditions for synthesis and the range of existence of the monoclinic TlS modification in the Tl-S system have been determined by means of differential thermal, X-ray diffraction, and microstructural analyses. It was shown that the monoclinic phase is a structural analogue of TlGaSe 2 . Possible variants of format…
Distribution coefficients (D) of trace amounts of Ni 2+ , Co 2+ , Mg 2+ , Cd 2+ , Cu 2+ , Mn 2+ , Ca 2+ , and Fe 2+ have been determined during crystallization of ZnSO 4 ·7H 2 O. Their dependencies on the ionic radii of M 2+ ions, solubilities and structures of the corresponding sulfates as well as their abilities to…
Abstract The current status and general applicability of scanning electron microscopy (SEM) at low voltages is reviewed for both imaging (low voltage scanning electron microscopy, LVSEM) and chemical microanalysis (low voltage energy-dispersive X-ray spectrometry, LVEDX). With improved instrument performance low beam…
A relationship exists between factor groups of space groups and subperiodic groups. This relationship, an isomorphism between factor groups of reducible space groups and subperiodic groups, can be used in the derivation of higher-dimensional space groups, of lattices of space groups, and of irreducible representations…
Abstract In large bandgap semiconductors and insulators, the threshold energies for e–h pair production and ionization damage can lie above the vacuum level. For low energy imaging, a window is then opened whose width is potentially sensitive to local changes in work function, doping level, or acidity. Recent progress…
The stability and reproducibility of current–voltage curves of Schottky barrier structures on particular porous silicon surfaces used for obtaining electroluminescence is greatly improved by first coating the surface with a conducting polymer, poly-4-dicyanomethylene-4H-cyclopenta [2,1-b:3,4-b′] dithiophene. With such…
We present a self-consistent effective-medium theory for the giant magnetoresistance of magnetic granular samples and doped ${\mathrm{LaMnO}}_{3}$ perovskites on the basis of the resistor network model. Most of the characteristic features of the field and temperature-dependent magnetoresistance can be qualitatively ex…
The title compound, Na8[MnW6O24]·18H2O, exhibits a structure with six WO6 octahedral edge-sharing units surrounding a central centrosymmetric MnO6 octahedron, with all metal atoms in a common plane. There are three unique Mn—O distances of 1.903 (7), 1.905 (7) and 1.941 (7) Å [average 1.916 (17) Å], while the average…
Different types of sulfobetaines and their corresponding cationic monomers and polymers derived from N,N-dialkylamino phenyl methacrylamide have been synthesized for this study. Comparing the chemical shifts in 1H and 13C NMR of the methylene groups in the cationic monomers and betaines reveal that the respective meth…
X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) have been employed in the investigation of the surface chemistry and oxidation-resistant property of the C-, N-, and Cu-containing films, formed by the plasma treatment of pristine copper. The copper oxidation process has been elucidated usin…
The crystal structure of α-RbB3O5 was refined by the Rietveld method with due regard for anisotropic vibrations of rubidium atoms to R p = 2.93, R wp = 3.80, R B = 2.53, R F = 2.84, and s = 1.54. The compound is isostructural to CsB3O5: it is orthorhombic, sp. gr. P212121, a = 8.209(1), b = 10.092(1), c = 5.382(1) Å,…
The high temperature phase behaviour of NH4H2PO4 (ADP) was studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and thermogravimetric (TG) analysis in the temperature range of 300 to 500 K. The DSC results show peaks at 430 and 483 K, that are associated with different phase transformations. The…
A vector hysteresis modeling algorithm is suggested to model the hysteresis phenomena of an isotropic magnetic material. The algorithm combines the Stoner-Wohlfarth and Preisach models. The vector property of each single domain magnetic particle with uniaxial anisotropy, which is supposed to constitute the magnetic ma…
Electron spin resonance experiments have been performed on single crystals of $\mathrm{KTm}({\mathrm{MoO}}_{4}{)}_{2}.$ In the frequency range from 10 to 190 GHz, the magnetic field dependence of absorption spectra of the ${\mathrm{Tm}}^{3+}$ ions is studied at helium temperatures for different crystal orientations. I…