Materials Literature
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Addition of molybdenum compounds to silica-supported platinum catalysts results in an increase of their activity for methanol formation. The location of the promoter has been studied and it is suggested that the molybdenum oxide partly covers the Pt surface. The respective roles of Pt and Mo in methanol formation are…
Abstract Dodecenyl succinic anhydride (DDSA), a liquid anhydride curing agent for epoxy resins, was synthesised from C 12 olefin and maleic anhydride by the “ene synthesis” reaction. C 12 olefin was prepared by the dehydration of lauryl alcohol using Al 2 O 3 (acidic) catalyst. The dehydration was carried out in a flo…
Castable polyester polyurethane elastomers (PU's) based on the system polycaprolactone diol (Capa 225)/trans 1, 4–cyclohexane diisocyanate (CHDI)/1,4 butane diol (1,4–BD) were synthesised to study the effect of various polyol-diisocyanate block ratios on thermal stability. The influence of mixed diisocyanates on therm…
The microstructure and mechanical properties of commercial pure titanium (CPTi) and Ti-6Al-4V alloy joints brazed with newly developed Ti-base amorphous filler metals have been investigated by microscopy, electron probe microanalysis, tensile test, fatigue test and salt immersion test.The developed amorphous filler me…
The synthesis, structures, and solid state properties of salts of general stoicheiometry [C]n+[A]n–, where C indicates a cluster cation and A represents a cluster anion, are described.
The crystal structure of the complex [(H2O)4Cu(cdta)Ni]·3H2O (1)(cdta =trans-cyclohexane-1,2-diamine-NNN′N′-tetra-acetate) has been determined by X-ray methods. It crystallizes in the triclinic space group P with Z= 2 in a cell of dimensions a= 8.685(4), b= 11.415(6), c= 12.841(4)Åα= 96.43(4), β= 96.60(3), γ= 102.23(6…
We discuss the spreading of a semi-dilute solution of neutral, flexible chains on a solid surface, assuming that a) the solvent is good and is non-volatile (dry spreading) and b) the polymer does not adsorb on either interface (solid/liquid and liquid/air). The polymer solute has two main effects : a) it modifies the…
Abstract Interpenetrating polymer networks based on polyurethane and polyurethane ionomer were studied using wide‐angle and small‐angle X‐ray diffraction. The polyurethane network is a multiblock polymer based on the trimethylolpropane adduct with 2,4‐toluene‐diisocyanate and poly(propylene oxide tetrahydrofuran) copo…
A computer program has been developed for calculating the activity coefficients of aqueous silica species. This program allows to the testing of the saturation states of silicate minerals in solutions concentrated by evaporation, particularly in alkaline brines. This has been done first for water samples from the Lake…
Egg white (albumen) can be used to improve the foam characteristics of beers. Hydrolysis increases the foam potential of albumen to a level considerably superior to that of beer polypeptides and commercial whipping proteins from soy beans and also removes any tendency to cause hazes in pasteurized beer. It appears, ho…
Explication a partir de differentes discussions du mecanisme de durcissement par deformation lors de la formation des bandes de deformation, ces bandes etant reliees a la structure de dislocations et au systeme de glissement
A range of surface treatments including chromate and plasma etching, which are capable of producing both chemical modification and surface topography modification of polymer surfaces, were applied to polyetheretherketone. The resulting surfaces were characterized by X-ray photoelectron spectroscopy (XPS), scanning ele…
A single-crystal X-ray analysis of the salt [dbttf][SnEt2Cl3] has revealed that both the dibenzotetrathiafulvalenium radical cations, dbttf˙+, and the [SnEt2Cl3]– anions exist as dimers. The crystals are triclinic, space group P, with cell dimensions a= 12.795(3), b= 12.960(5), c= 7.463(1)Å, α= 95.86(3), β= 108.62(2),…
Par chauffage de melanges Cu 2 O-Ta 2 O 5 sous vide entre 800 et 1100 o C, preparation de deux phases intermediaires de compositions tres proches; Cu 5 Ta 11 O 30 et Cu 3 Ta 7 O 19 . Structures de ces phases
The Rietveld refinements of crystal structure were undertaken on powder samples of ZrO2 and HfO2 quenched from 600°C⋅6GPa. The results on orthorhombic ZrO2 were consistent with those of a single crystal obtained under pressure. The compressibility of this phase was calculated as 4.65×10-3GPa-1. The results on HfO2 wer…
Abstract A factorial experimental design determined separate and combined effects of MeCoB 12 (methylcobalamin) and Me 2 Co(N 4 ) + (a methylcobalamin model) on methylation of Sn(II) and Pb(II) in sediment matrices. Total methyltin yields ranged from 1.4% to 3.2%, and total methyllead yields varied from 0.037% to 0.11…
Unlike its metal-free precursor and NiII analogue, meso-tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)- porphyrinatopalladium(II) undergoes very little aerial oxidation in basified dichloromethane, owing to metal-enforced planarity of the porphyrin macrocycle, as shown by crystal structure determinations of the two complexe…
Le comportement des électrons dans la matière est d'un intérêt fondamental, notamment en microscopie à balayage, en microanalyse et en physique spatiale. Nous présentons dans cet article l'ensemble de nos résultats expérimentaux dans le domaine de la diffusion multiple pour un faisceau d'électrons monocinétiques tomba…
Abstract Mechanical and rheo‐optical data have been obtained as a function of frequency at constant temperatures for two series of spherulitic and nonspherulitic samples of isotactic polypropylene having different ordering on molecular level. It was found that the structure differentation influence on the nature of th…
A radioisotope labeling technique was used to quantify the adherence of Staphy lococcus aureus, Staphylococcus epidermidis, and Escherichia coli on eight fabrics. The extent of bacterial adherence depends on the bacterial type, the fiber content, and the contact condition. Staphylococci adhered more than Escherichia c…