Materials Literature
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Abstract Gezielte Versuche zur Synthese neuer Halogenochalkogen(IV)‐Säuren führten mit Tellur und Brom zu den neuen Verbindungen [H 3 O(Benzo‐18‐Krone‐6)] 2 [Te 2 Br 10 ] ( 1 ) und [H 5 O 2 (Dibenzo‐24‐Krone‐8)] 2 [Te 2 Br 10 ] ( 2 ). Die [Te 2 Br 10 ] 2‐ ‐Anionen bestehen aus zwei kantenverknüpften verzerrten TeBr 6…
Experimental evidence indicates that nickel-base alloys fail in the presence of hydrogen by ductile intergranular fracture. The degradation mechanism involves void nucleation at grain boundary carbides and grain boundary decohesion. In this study, a micromechanical model is suggested to understand the interaction of v…
Commercial carbon NORIT and carbon xerogel samples were modified in an oxidizing atmosphere (wet and dry oxidation) and than subjected to physico-chemical characteristic, including temperature-programmed desorption (TPD) of CO and CO 2 , and spectroscopic analysis. Surface changes due to oxidation procedure were monit…
A phase-field model is proposed to describe epitaxial growth. In this model the motion of island boundaries of discrete atomic layers is determined by the time evolution of an introduced phase-field variable. We use formally matched asymptotic expansion to determine the asymptotic limit of vanishing interfacial thickn…
By means of a centrifugal casting method, high speed steel (HSS) rolls with excellent wear resistance have been manufactured. The hardness of the HSS rolls was 65–67 HRC, the range of hardness variation was smaller than 2 HRC and the impact toughness exceeded 15 J. The wear rate of the rolls was 2.5 × 10−4 mm t−1 of s…
AlN powders were coated with a protective layer at temperatures between 1150‐1450°C in a vacuum by the reaction with SiO vapor. The waterproof property of the coated AlN powders was studied. The composition of the protective coating varied with the coating temperature. Si‐coated AlN powders at 1200°C showed excellent…
Thin polymer films with thicknesses of tens of nanometers are studied extensively because they provide an ideal sample geometry for studying the effects of one-dimensional confinement on the structure, morphology, and dynamics of the polymer molecules and because they are used extensively in technological applications su…
A very high-current liner implosion experiment was conducted, using an explosive magnetic-compression generator (EMG) to deliver a peak current of 102 /spl plusmn/ 3 MA, to implode a 4.0-mm-thick aluminum liner. Analysis of experimental data showed that the inner surface of the liner had attained a velocity of between…
This study explores the possibility of overcoming the problem of hygroscopicity of ammonium nitrate by coating the particles with selected waterproofing materials. Gravimetric analysis of the samples of ammonium nitrate coated with eight different waterproofing materials, vis-a-vis, uncoated ammonium nitrate, were con…
In the ${\mathrm{Li}}_{1\ensuremath{-}x}{\mathrm{Na}}_{x}\mathrm{Ni}{\mathrm{O}}_{2}$ solid solutions, three different single-phase regions exist: for $x\ensuremath{\geqslant}0.9$, for $x\ensuremath{\approx}0.7$, and for $x\ensuremath{\leqslant}0.3$. Although the intermediate compound does not show the cooperative Jah…
The paper presents temperature behavior of the splay and bend elastic constants measured for n-hexyloxycyanobiphenyl and noctyloxycyanobiphenyl mixtures -a system exhibiting the re-entrant nematic phase. It was shown that singularities in the elastic properties of the system concern not only the nematic phase (the wel…
Precursors for zircon–carbon mixtures were made to coat fibers for ceramic‐matrix composites. Precursors were characterized using XRD, TGA, and DTA. Zircon formed from vanadium‐ or lithium‐doped precursors after heat treatments at ≥900°C in air, but it did not form at 1200°–1400°C in argon when large amounts of carbon…
Molecular sieve carbon (MSC) nanoparticles were successfully synthesized by carbonization of poly(furfuryl alcohol) (PFA) particles using silica as a temporary barrier to prevent irreversible aggregation of nanoparticles, and they showed good dispersibility in various organic solvents.
The effect of a localized SiO 2 codoping on the conversion of polycrystalline, MgO‐doped Al 2 O 3 tubes to single‐crystal sapphire was investigated. Codoping with SiO 2 before sintering intentionally triggered abnormal grain growth, which resulted in the full conversion of tube surfaces to single crystal without adver…
In the present work, the time-dependent density functional theory (TD-DFT) is applied to study the electronic transitions which give rise to the near-ultraviolet−visible (near-UV−vis) optical absorptions of 3,4-dimethyl- N -{2-[10,15,20-tris-(3,5-di- tert -butyl-phenyl)-porphyrin-5-yl]-phenyl} benzamide (H 2 P−O34) an…
Abstract This study was carried out to investigate the influences of compounding process and surface treatment on calcium carbonate (CaCO 3 ) filled polypropylene. The compounding process is discussed with reference to a twin‐screw extruder and an internal mixer. The calcium carbonate filler was surface‐treated with a…
Muthmannite, AuAgTe 2 , a rare gold-silver telluride was discovered in a sample from the historical mineralogical collection of the Naturhistorisches Museum of Vienna. The sample is from the gold-telluride deposit of Sacarîmb, Metaliferi Mountains, western Romania. Muthmannite occurs as anhedral grains up to 200 µm as…
Machining of metals is characterised by plastic deformation occurring at high strains, strain-rates and temperatures. In the few predictive machining theories reported in literature, two types of constitutive equations, the power-law relation and Johnson-Cook equation, have mainly been used for describing the material…
For collectively interacting repulsive colloids driven on triangular substrates, we show that a number of distinct dynamical regimes arise as a function of the drive strength. Additionally, we show that for certain directions of drive a spontaneous-symmetry-breaking phenomenon occurs where all the colloids can flow in…
The selective meso-monobromination of 5,15-diarylporphyrins is difficult to achieve and extensive chromatography is required to obtain pure products. A sequence of (i) dibromination, (ii) selective monoinsertion of Pd ( dppe ) (dppe = 1,2-bis(diphenylphosphino)ethane) and (iii) hydrodepalladation using methanolic base…