Materials Literature
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Silicon, an indirect gap semiconductor, can emit light with 10% efficiency at room temperature, provided that it is in the form of low-dimensional (quantum dots or wires) nanostructures. Porous silicon is the best known example of such nanostructures. The luminescence mechanisms and the relationship between bandgap en…
Abstract The crystal and molecular structure of Sn 2 P 2 Se 6 in the low temperature ferroelectric phase is determined by single crystal X-ray diffraction techniques. These results are compared with the crystal structure of the same compound in the paraelectric phase, which was redetermined at room temperature. In bot…
Three Ni/TiO2 samples have been synthesized by impregnation (sample Ni-i-Ti), adsorption of Ni2+ ions from alkaline media on TiO2 (sample Ni-1-Ti) and on reduced Ni-1-Ti (sample Ni-2-Ti). The samples have been characterized by TPR, IR spectroscopy of adsorbed CO and X-ray diffraction. Impregnation leads to a less homo…
Dimeric ortho-phenyleneindium bromide 1 shows a higher affinity for 1,2-diazines than for 1,3- and 1,4-diazines; as shown by the X-ray crystal structure analysis of the host–guest complex 3 the observed selectivity results from subtle structural variation which can bring the indium p orbitals to converge.
Systems undergoing an equilibrium phase transition from a liquid state to an amorphous solid state exhibit certain universal characteristics. Chief among these are the fraction of particles that are randomly localized and the scaling functions that describe the order parameter and (equivalently) the statistical distri…
The first Pd dithiolene [Pd(Et2timdt)2] 4a belonging to the new class of metal dithiolenes deriving from the R12timdt (R12timdt = monoanion of 1,3-dialkylimidazolidine-2,4,5-trithione) ligand has been characterised by X-ray crystal structure determination on a single crystal [monoclinic, space group P21/n, a = 9.545(2…
In order to determine effects of hydrogen peroxide on stress corrosion cracking of structural materials in the primary cooling systems of boiling water reactors, a high temperature high pressure water loop with controlled hydrogen peroxide concentrations and lower possible oxygen concentrations has been fabricated. Te…
The diversity of subjects involved in marine corrosion and fouling processes are evident in the approaches and techniques described in this book. An improvized understanding of biologically influenced corrosion and fouling processes is essential to the development of better corrosion protection systems, and this book…
Observations of the space charge distribution around water trees are reviewed, and the nature of water trees analyzed from those results is discussed. It was concluded that at least two mechanisms are responsible for the formation of space charges. One is interfacial polarization due to the high conductivity of a tree…
The guidelines, or empirical rules, previously described in the literature to estimate ceramic compositions from preceramic polymer compositions have been refined and quantified. Thermogravimetric and residual gas analyses of the pyrolysis of organosilsesquioxane polymers have identified the organic degradation produc…
A survey of the available data on the oxygen positions in various tetragonal zirconias reveals a simple, approximate relationship between the departure of the oxygen from the position it would have in the ideal fluorite structure, and the tetragonality ( c/a ) of the material. This relationship can be understood on th…
The effect of the microstructure on the phase behavior of mixtures of polybutadiene (PB) and poly(ethylene- co -1-butene) (PEB) with polystyrene (PS) has been investigated. A series of PBs with 1,2-addition content ranging from 7 to 93% were synthesized by anionic polymerization, and a portion of each was subsequently…
Ferrocene-based derivatives such as 4-{3-[4-(octyloxy)benzoyl]thioureido}phenyl 4-ferrocenylbenzoate and other higher homologues (n=12,16 and 18; n=length of alkoxy chain) were prepared by reacting 4-alkoxybenzoyl isothiocyanates with the corresponding amines containing the ferrocenyl moiety. Their mesomorphic propert…
EDS analysis on standard samples of minerals and glasses. In this paper is reported the setting up of a EDS microanalitic system present at the laboratory of elec tron microscopy and microanalysis at the Dipartimento di Scienze della Terra of Pisa University. Pure element inten sity factors for the standardless softwa…
The main features of negatively charged images are: bright regions are always accompanied by a dark region, which corresponds to the region above connecting lines in LSI, and dark regions seem to encroach the bright region. These features are explained by a new model, which contains redistribution and multiplication o…
Die Titelverbindungen werden durch Reaktion der Cyclopentadienidchloride [M(C5H5)2Cl]2 mit LiNPPh3 in siedendem Toluol hergestellt und durch Kristallstrukturanalysen charakterisiert. Alle drei Verbindungen kristallisieren isotyp miteinander in der orthorhombischen Raumgruppe Pbca mit Z = 8. Zwei der drei Phosphanimina…
Emphasis is placed on the growing body of evidence demonstrating the importance of mechanical factors in the initiation and growth of electrical trees in solid polymeric insulating materials. Specimens using point-plane electrode geometries in homogeneous resins, with and without barrier inserts, have been investigate…
A new tetranuclear nickel compound, showing µ-CO3 bridges and butterfly topology has been synthesised and structurally characterised. The complex [Ni4(µ-CO3)2(aetpy)8][ClO4]4, where aetpy corresponds to (2-aminoethyl)pyridine, crystallises in the tetragonal system, space group P4(2)2(1)2 (no. 94), a = 14.523(4), c = 1…
Titania pillared H 4 Nb 6 O 17 has been synthesised by the intercalation of [Ti(OH) x (CH 3 CO 2 ) y ] z+ followed by photodecomposition with UV light irradiation. The incorporation of TiO 2 in the interlayer of H 4 Nb 6 O 17 has been confirmed by powder X-ray diffraction, DTA, UV-VIS reflectance and BET measurements.…
A new and unexpected tetrathiafulvalene (TTF) core building process is observed via reaction of a 1,3-dithiole phosphonate anion with a 2-oxo-1,3-dithiole functionality.