Materials Literature
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The origin of the sublinear frequency dependence of the ac conductivity is discussed using percolation theory. Different physical bases for calculation in different frequency regimes are discussed. Both the crossover frequencies separating the frequency regimes and the different results for the conductivity are given.…
α-boron is the most simple structure of all boron modifications having one B12 icosahedron per (rhombohedral) unit cell. The conventional, free atom crystal structure refinement with R = 6.2% indicates considerable charge redistribution into covalent bonding. In a high order-low order and multipole refinement the R va…
We cool emulsified liquid water below 130 K at a rate of 103–104 K s−1 at ≈0.5 GPa and vitrify it under pressure. We recover the produced glassy sample at 1 bar and 77 K, and examine it by Raman spectroscopy, x-ray diffraction, and visual observation. We find that the emulsified glassy water, when heated from 77 K at…
Localizing cavitation to the kidney stone in extracorporeal shock wave lithotripsy may be desirable since cavitation appears to play a major role in both stone comminution and renal tissue damage. A method has been developed to localize and intensify cavitation damage in vitro. Cavitation fields in water were filmed w…
Microbiologically influenced corrosion (MIC) of plain carbon steel in anaerobic soil was investigated using field survey, the electrochemical polarization technique, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), a thin-film electrica…
Phthalic acid esters are important additives in polyvinyl chloride (PVC) products. Since PVC plastisoles for the production of wallcoverings contain about 30% phthalic acid esters, it is a crucial question whether these products can contribute to the pollution of the indoor environment. In this study, the emission of…
This review explores piezoelectric ceramics analysis and characterization. The focus is on polycrystalline ceramics; therefore, single crystals, polymeric materials and organic/inorganic composites are outside the scope of this review. To thoroughly grasp the behavior of a piezoelectric polycrystalline ceramic, a basi…
Besides surface chemistry, the surface roughness on the micrometer scale is known to dominate the wetting behavior and the biocompatiblity properties of solid-state materials. The significance of topographic features with nanometer size, however, has yet to be demonstrated. Our approach is based on well-defined Ge nan…
Abstract Ten montmorillonites of different origins with variable Fe contents were analysed using transmission IR spectroscopy. Special attention was devoted to the OH-bending region to obtain information about the distribution of octahedral cations. For low to medium Fe contents (≤0.56 per Si 8 formula unit), a linear…
A time-resolved SANS method was developed for the determination of unimer exchange kinetics of polymeric micelles under equilibrium conditions. Measurements were performed on the system PEP-PEO/DMF exploiting the large difference in scattering length density of protonated and deuterated species. In contrast to theoret…
One-dimensional (1D) nanostructures have numerous potential applications in science and engineering. Nanocomposites made of nanowires, such as carbon nanotubes, are likely to decrease material’s density and increase its strength,[1] which are of critical importance to space technology. To investigate the uniqueness of…
Ab-initio density-functional molecular dynamics simulations and full relaxation of all atomic positions are used to reconcile the crystal structures with IR spectra of dickite and kaolinite. The relaxation of atomic positions preserves the accepted space group symmetries. A pair of two hydroxyl groups oriented paralle…
We use molecular dynamics computer simulations to study the relaxation dynamics of a viscous melt of silica. The coherent and incoherent intermediate scattering functions, F(q,t) and F(s)(q,t), show a crossover from a nearly exponential decay at high temperatures to a two-step relaxation at low temperatures. Close to…
Experimental observations from (sub-)micrometer spheres of silica are compared with the results from conventional MCM-41 material. SEM images give proof of a spherical morphology (see Figure), which is also confirmed by TEM. XRD patterns confirm that on a local scale the pores are hexagonally packed whilst on a larger…
Transparent Pb(Zr, Ti)O 3 (PZT) thin films with over 1 µm thickness were deposited by the aerosol deposition method (ADM). The transparency of the PZT thin film deposited at room temperature strongly depended on the kinds of carrier gases and the particle flow velocity. The color of the film became black if He gas was…
Strain IPT101T, isolated from the soil of a sugar-cane plantation in Brazil, was analysed in a polyphasic taxonomic study. The strain produces polyhydroxyalkanoates from sucrose and other carbon sources. Morphological, physiological and biochemical data as well as 16S rDNA, whole-cell protein and fatty acid analyses i…
Summary A new measuring technique based on a capillary rise method has been developed to quantify the wettability of more or less decomposed peats (the main materials used as horticultural growing media) in relation to their water content. A preliminary study of their physico‐chemical and biochemical characteristics e…
Highly syndiotactic “living” poly(propylene)s were synthesized at 25°C using a bis[N-(3-tert-butylsalicylidene)-2,3,4,5,6-pentafluoroanilinato]titanium (IV) dichloride/MAO catalyst system, and microstructures of the polymer were analyzed by means of 13C NMR spectroscopy. The syndiotactic poly(propylene) contains isobu…
The effect of the Ba/Ti ratio on microstructure, dielectric/ferroelectric properties, and domain width was studied using optical microscopy, ɛ( T ) curves, D – E hysteresis, and transmission electron microscopy. Although Ti‐excess samples showed abnormal grain growth and a decrease of room‐temperature permittivity due…
Piezoelectric properties of potassium niobate (KNbO 3 ) single crystals were investigated as a function of crystallographic orientations, i.e., [110] c of polar direction and [001] c of nonpolar direction. Prior to the piezoelectric measurements, the optimum conditions for a conventional poling method were investigate…