Materials Literature
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The absorption and permeation of H into transition metals under conditions of cathodic polarization or wet corrosion is commonly enhanced by adsorbed catalyst poisons which, however, decrease the coverage by adsorbed H, the intermediate in the hydrogen evolution reaction. This unexpected direction of behaviour has rem…
The copper(I)-templated synthesis of the first [2]catenate incorporating electron-donor and -acceptor porphyrins linked mechanically, though not covalently, has been achieved, along with that of related model compounds incorporating only electron donating zinc(II) porphyrins. The preparations were approached by first…
The XPS spectra of aluminum phosphate were collected with a VSW HA150 using monochromatic Al Kα x-radiation. Monochromatic radiation provides a distinct clarity to the rich peak structure in the valence band of aluminum phosphate due to the absence of interfering x-ray satellites from the intense O 2s region. The vale…
X-ray photoelectron spectra were measured on the fresh surfaces of silica, binary alkali silicate and mixed alkali silicate glasses fractured in ultra-high vacuum by irradiating with focusing monochromatic AlKα X-ray. Binding energies and chemical shifts of O1s, Si2p, Li1s, Na1s, K2p, Rb3d5/2 and Cs4d5/2 have been inv…
A general approach for the rational synthesis of linear trinuclear complexes containing three different metals MAMBMC is described and a member of the series, FeIIICuIINiII, has been characterized by X-ray crystallography and magnetic susceptibility measurements.
Porphyrin-core dendrimers consisting of benzyl ether dendrons assembled around a porphyrin core have been prepared by two different convergent syntheses. The first involves the direct condensation of convergent dendrons having 3,5-disubstituted benzaldehyde focal points with an equivalent amount of pyrrole. This route…
meso-η1-Palladio- and platinioporphyrins have been isolated for the first time by means of oxidative addition of bromoporphyrins to Pd(0) and Pt(0) complexes; the X-ray crystal structure of the title complex was determined.
Ti-beta catalyses the oxidation of small- and medium-sized silanes to the corresponding silanols by aqueous (30%) H2O2 as oxygen donor with high conversions and excellent selectivity (no disiloxane).
Evolutional changes in interior structures of mixed population biofilms grown on domestic wastewater were quantitatively analyzed using a cryosectioning technique and an image analysis. Meanwhile, transport of particulates into the biofilms was also experimentally investigated using fluorescent microbeads as tracers t…
By surveying the most used methods for evaluating the kinetic parameters from nonisothermal experiments, a new classification scheme of the methods is proposed. For each method the number of principles and theoretical approximations required to derive the equation which grounds it, is considered as a comparison criter…
The crystallisation of xFe 2 O 3 (100-x)P 2 O 5 , (14≤x≤40) glasses has been investigated by differential thermal analysis, x-ray diffraction analysis and Raman spectroscopy. The glasses were heat treated in dry argon from 298 to 1143 K. The crystallisation temperature and number of crystallised phases depended upon t…
Hydrogen outgassing is the most significant factor limiting the attainment of outgassing rates below 10−12 mbar l s−1 cm−2 in stainless steel vacuum systems. This limit turns out to be crucial in very large vacuum systems, like the VIRGO vacuum tubes (2 tubes 1.2 m diam, 3000 m length). Heating the raw material at 400…
A new three phase transformer model is presented in this paper, taking into account air gaps, saturation, core losses, and lamination anisotropy. The flux distribution in a straight overlap joint has been investigated using a lumped circuit model. It is shown that the actual air gap varies largely between an upper and…
The trans-oxamidato-bridged polymeric complexes [Cu2(trans-oxen)(µ-OH)(µ-H2O)]nBrn·2nH2O 1 and [Cu2(trans-oxen)(µ-OCN)2]n·nH2O 2 [H2oxen = N,N′-bis(2-aminoethyl)oxamide] with zig-zag co-ordination chains were synthesized and characterized by single-crystal X-ray diffraction methods. The cationic chains [{Cu2(trans-oxe…
Dicarboxylic L-valyl-L-valine bolaamphiphiles produced nanoscale fibers with widths of 10–30 nm, via proton-triggered self-assembly in water, which are dominated by both intralayer, lateral hydrogen-bond networks between end carboxylic acid groups and parallel β-sheet networks between amide groups.
Strictly linear amyloses have been heated in a sealed ampoule in the presence of salicylic acid (SA). When using an amylose of molecular weight 1310000 (AS-1310), two types of inclusion complexes, differing in helix structure, were formed, depending on the amount of SA. With 10% SA a complex with 71-helix structure wa…
A physical modelling investigation has been undertaken to determine the relationship between the physico-chemical properties of the liquid phase, the gas bubble size, the gas flux, and the residence times of gas in spherical foams. The testwork was conducted in a 107 mm diameter glass column in a temperature controlle…
Electrochemical interconversion between 9,9,10,10-tetraaryldihydrophenanthrene 1 and 2,2′-bis(triarylmethylium) 22+ has been proven to proceed via open form cation radical 2+· as a stable intermediate; using these three species, a novel tricolor electrochromic system that exhibits hysteretic color change (color 1 → co…
We have studied chiral induction in a nematic in contact with a chiral surface using computer simulations. Nematic and surface particles have been modelled using the Gay–Berne (GB) potential considering, additionally, a short-range chiral term for the inducing surface. We find that, close to the chiral surface, a twis…
We propose a generalisation of the Mullins–Sekerka problem to model phase separation in multi-component systems. The model includes equilibrium equations in bulk, the Gibbs–Thomson relation on the interfaces, Young's law at triple junctions, together with a dynamic law of Stefan type. Using formal asymptotic expansion…