Materials Literature
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Density functional theory (DFT) at the hybrid B3LYP level has been applied to the germanium clusters Ge8z(z=-6, -4, -2, 0, +2, +4) using nine initial geometries. For Ge8(2-) the D2d bisdisphenoid structure predicted by the Wade-Mingos rules is not computed to be the global minimum but instead lies 3.9 kcal mol-1 above…
Infrared attenuated total reflection spectroscopy has been used to observe the surface chemistry of Si 3 N 4 films (grown on Si by low-pressure chemical vapor deposition) under steady-state conditions during exposure to dilute aqueous HF solutions. Surfaces etched in HF do not exhibit rapid growth of an SiO 2 layer wh…
We derive a general theory for imaging by a flat lens without optical axis. We show that the condition for imaging requires a material having elliptic dispersion relations with negative group refraction. This medium is characterized by two intrinsic parameters sigma and kappa. Imaging can be achieved with both negativ…
A family of hybrid organic–inorganic network materials—the star gels and glasses—has been synthesized from highly functional poly(alkoxysilane) molecular precursors. The starting silanes comprise an atomic, linear or cyclic core with multiple flexible arms which terminate in network-forming trialkoxysilane groups. Wit…
New macrocycles incorporating a porphyrin and a [small pi] electron-rich aromatic were prepared from a dynamic disulfide library. The outcome could be influenced by use of templates.
A mononuclear cobalt(II) complex CoL5, containing the pentadentate O2N3 salen-type Schiff-base ligand H2L5=N,N[prime or minute]-bis(3-tert-butyl-2-hydroxy-5-methylbenzylidenyl)-1,7-diamino-4-methyl-4-azaheptane, exhibits magnetic ordering at 4 K as proven by ac magnetic susceptibility (both in- and out-of-phase), magn…
Y2O3:Eu red phosphor powder was synthesized with powders of metal–ethylenediaminetetraacetic acid (EDTA) complexes as a starting material. The compositional analysis of each metal–EDTA complexes particle and Y2O3:Eu particle was performed using a particle analyzer. In this study, first, the particles of a mixture of Y…
The redox behaviour of Pd-based TWCs is studied under dynamic, cycling conditions (e.g. lambda oscillations) on a 50 millisecond scale. Pd temporal response to gas inlet mixture changes is governed by metal-promoter interface properties.
Abstract The relationship between morphology and deformation behavior of selected ethylene/1‐octene copolymers (EOCs) and their blends with high density polyethylene (HDPE) was investigated. The copolymers showed, depending on the 1‐octene content, different morphologies ranging from lamellar to worm‐like crystalline…
Several swelling mica-type clays of nominal compositions, NaxSi8−xAlxMg6O20F4·yH2O where x = 4, 3 or 2 were prepared using kaolinite, silica gel or silicic acid, magnesium fluoride and sodium chloride in the temperature range of 800 to 1100 °C after treatment for 5 to 15 h. All the synthetic clays were characterized b…
Magnetoelectric materials may be applicable in magnetic and ferroelectric devices, because they exhibit both magnetic and electrical ordering over a range of temperatures. One of the few magnetoelectic materials is BiFeO 3 . Large particles of (bulk) BiFeO 3 have a perovskite structure, a Neel temperature ( T N ) of 3…
Protein X-ray crystallography is now a relatively high-throughput technique that plays a major role in structure-based drug design programs where the method of soaking small organic ligands into protein crystals is used to confirm or identify binding modes. In this review, we discuss some experimental approaches for ‘…
By using homochiral mesoporous POST-1 (Scheme 1) as an inherently chiral sensitizing host, supramolecular enantiodifferentiating photoisomerizations of (Z)-cyclooctene (1Z) were performed for the first time to examine the sensitizing ability of the chiral nanopores, walls of which are decorated with pyridine chromopho…
Abstract In the five-component permanent magnets based on Sm2Co17 the formation of the familiar microstructural features (2:17 cell, 1: 5 cell wall, and 1: 3 lamellae) are elucidated with the help of recent and past information on the phase equilibria and crystal structures. Contrary to Zr-free alloys, in which the 1:…
Strengthening effects of quasicrystalline icosahedral phase has been studied in two alloys Mg95Zn4.2Y0.8 and Mg92.5Zn6.5Y extruded at 250 and 400 8C. The quasicrystal particles are facetted and show definite orientation relationships with the matrix. Due to its high symmetry and quasiperiodicity, the icosahedral phase…
The influence of excitation density on luminescence decay in Y3Al5O12:Ce and BaF2 crystals at room temperature was investigated for the first time using pulsed free electron laser radiation in vacuum ultraviolet. Increased excitation density led to the remarkable shortening of luminescence decays with non-exponential…
Abstract A synthetic route to a series of homochiral (and achiral) nitronyl nitroxides derived from rac ‐(and meso )‐3,4‐dimethyl‐3,4‐dinitrohexane is described. The two forms of this precursor, meso and rac , were identified unambiguously and reduced to the corresponding meso ‐ and rac ‐diamines. The rac ‐diamine was…
For diatom biologists one of the most interesting research areas over the next years will be in linking mathematical models for pattern formation with information derived from molecular genetic, biochemical, and physiological studies. A major goal of this research is to exploit diatom proficiency in biogenic silica fo…
We have reported that the Pd-perovskite catalyst regenerates itself through the solid solution and segregation of Pd in and out of the perovskite crystal during the inherent fluctuation of engine exhaust gases. We named this innovative ceramic the “intelligent catalyst.” In this study, the structural stability and the…
Polished sections of tuyere coke were studied by optical and scanning electron microscopy and wavelength-dispersive analysis (WDS) to reveal structural and chemical changes occurring with mineral phases (K- and Na-, ±Ca-bearing aluminosilicates). The aluminosilicates in the tuyere coke form new compounds, which occur…