Materials Literature
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The synthesis and structural characterization of a novel series of deep-red mixed-valence (MoVI/MoV) compounds with nano-sized spherically shaped cluster anions containing 18, 40, or 54 Mo atoms, respectively, is reported: Na10[H4Mo18O56(CH3COO)2] × ca. 36 H2O × 3 CH3COOH (1), (NH4)12Na12[Mo40O128] × ca. 70 H2O (2), (…
The structures and energy characteristics of a new class of nanotubes and fullerenes formed by binary layers of a trigonal network of metal atoms M and a graphite-like network of boron atoms are considered by the example of magnesium and zirconium diborides. It is shown that, contrary to the familiar carbon monolayer…
We present magnetization measurements on lightly doped ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{MnO}}_{3}$ single crystals with $0.06<~x<~0.15$ in external fields up to 14 T at temperatures between 4.2 and 180 K. In contrast to the ferromagnetic behavior which is found for $x>~0.11,$ the sam…
The magnetic anisotropy and magnetostriction of a Lu 2 Fe 17 single crystal are investigated. The temperature dependence of the magnetic anisotropy constant K 1 is measured in the range 4.2–300 K. The results obtained are compared with the data calculated using the Callen theoretical formula. It is found that the temp…
A cryogenic experiment determining the dielectric susceptibility of the ferroelectric substance, strontium titanate, in the 90- to 300-K temperature range is described. Evidence is presented for a structural phase transition in strontium titanate at 110 K. The experiment is suitable for advanced students.
The chemical state of tungsten in the rust of low-alloy steel was analyzed by electroprobe x-ray microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS), and the electrochemical behavior of the rust was investigated by the electrochemical impedance spectroscopy (EIS) method after a wet/ dry cyclic corrosion te…
The synthesis of open-chain, tetrapyrrolic 2,2'-bisdipyrrin ligands was investigated, starting from a variety of different pyrrolic and 2,2'-bipyrrolic precursors. Four important observations were made: (1) The solubility of 2,2'-bisdipyrrins can easily be tuned through the peripheral substituent pattern, allowing the…
This paper describes the dependence on test parameters of the fatigue resistance of EPDM. Fatigue was investigated using dumbbell specimens under load control at 1 Hz until failure. Tests were made in order to create a common Wöhler (S–N) curve while increasing the stress amplitude and also to show the influence of in…
Thermomechanically coupled finite element analysis of the hot plane strain compression test has been carried out to investigate the effect of various test parameters on the measured response and deformation of specimens. The results are presented in a series of papers. In this paper (Part 1), the results of two-dimens…
A statistical model, the Ising model, is used to simulate liquid wetting of fibrous assemblies. The adhesive energy between fiber and liquid and the cohesive energy within the liquid are calculated by applying the Lifshitz theory under the assumption that the interactions between a fiber cell and a liquid cell and bet…
BACKGROUND: Tissue-engineered heart valve leaflets are a promising way to overcome the inherent limitations of current prosthetic valves. The aim of this study was to compare the biological responses of an autologous cell seeded scaffold and an acellular scaffold implanted in the pulmonary valve leaflet in the same an…
Crack growth along porous ceramic layers was studied experimentally. Double cantilever beam sandwich specimens were loaded with pure bending moments to obtain stable crack growth. The experiments were conducted in an environmental scanning electron microscope enabling in situ observations of various mechanisms associa…
Conjugated rod molecules bearing flexible coil polymer moieties on both ends self-organize into 1D or 2D structures, and eventually into a 3D tetragonal superlattice (see Figure), depending on the number of monomeric units in the coils. The 3D ordered rods exhibit a highly extended fluorescence lifetime over the 1D or…
By using the fluorescence line-narrowing technique, we observed a broad fluorescence band in the vicinity of a resonant line of the D05→7F0 transition in an Eu3+-doped SiO2 glass synthesized by a sol-gel process. The comparison with a similar line in an Al2O3–SiO2:Eu3+ sol-gel glass revealed the existence of a chemica…
The synthesis and magnetic properties of seven new nitronyl nitroxide substituted phenolates with chelating amine groups are reported. Copper(II) and nickel(II) complexes prepared with these ligands are structurally and magnetically characterized, showing exchange interactions between the metal and the radical ligands…
High-resolution transmission electron microscopy (HRTEM), electron microdiffraction, and X-ray diffraction were used to study hydroxyapatite specimens with particle sizes from a few nanometers to several hundreds of nanometers. Diffuse scattering (without clear reflections in transmission diffraction patterns) or stro…
Surface and textural properties of Zr-doped silica [ x ZrO 2 -(100 − x )SiO 2 ] have been investigated as a function of zirconium content in the range of x = 5 to 50 (mol % Zr) via heating their respective xerogels (prepared with a novel sol−gel route developed recently) in air at 500 °C for 4 h. Nitrogen adsorption−d…
The temperature dependence of tensile fracture behavior and tensile strength of a two‐dimensional woven BN‐coated Hi‐Nicalon™ SiC fiber‐reinforced SiC matrix composite fabricated by polymer infiltration pyrolysis (PIP) were studied. A tensile test of the composite was conducted in air at temperatures of 298 (room temp…
In this work, the dynamic mechanical behavior of jute fiber-reinforced epoxy foams was investigated. The influence of various fiber and microvoid content on shear modulus, frequency and log decrement was discussed. Experimental results showed that the 42 vol.% fiber content significantly enhances the shear modulus. Th…
Abstract A yellow sulfatotungstate complex was formed by heating a 50 mM W(VI)–2 M H2SO4–40% (v/v) CH3CN system at 70 °C for 14 days, being isolated as the tetrapropylammonium (n-Pr4N+) salt. An X-ray structural analysis (ortho-rhombic, Pca21 (No. 29) a = 27.181(1), b = 14.1428(6), c = 27.7292(9) Å, and Z = 4) reveale…