Materials Literature
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A DNA target model has been developed, based on the geometrical co-ordinates of individual atoms. This model is used to analyse DNA damage produced by Auger electron tracks from the decay of 125I. The high resolution of this target model enables the distinction between direct and indirect electron hits, i.e. hits insi…
The numerical methods which have been proposed by the present authors for Lamb waves in an anisotropic laminated plate and its transient responses are expanded for the wave propagation analysis of functionally gradient material (FGM) plates. The material properties of the plate change gradually in the thickness direct…
On etudie les zones de formation vitreuse et differentes proprietes de verres du systeme: Al 2 O 3 −SiO 2 −R 2 O x (ou R 2 O x =Nd 2 O 3 , Sm 2 O 3 , Tb 4 O 7 , Er 2 O 3 , Y 2 O 3 )
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNitrite-bound five-coordinate low-spin iron(II) model complex for the prosthetic group of nitrite reductase with an unusually large quadrupole splitting. Synthesis, Moessbauer properties, and molecular structure of the complex (nitro)(.alpha.,.alpha.,.alpha.,.alpha.-tetrakis…
The biodegradable polyesters, poly(hydroxybutyrate) (PHB) and poly(hydroxybutyrate-hydroxyvalerate) (PHBV) were investigated for use as sustained delivery carriers of a model drug, progesterone. Spherical microspheres containing the drug were prepared by an emulsion solvent-evaporation method with gelatin as an emulsi…
Abstract Quantitative electron probe microanalysis of nitrogen has been performed on 18 nitride specimens in the voltage range of 4–30 kV. A conventional lead stearate and a new W/Si multilayer analyzer crystal (2d = 5.98 nm) were used simultaneously. The net peak count rates on the latter crystal were approximately 2…
The dark-brown compound [N(Me)4]4[AsIII8VIV14O42(0.5H2O)] containing a spherical anion [AsIII8VIV14O42(0.5H2O)]4– containing condensed VO5 square pyramids and As 2O5 units, is synthesized hydrothermally from As2O3, V2O5 and (Me)4NOH and structurally characterized by X-ray diffraction.
Conditions for carbothermal synthesis of α‐Si 3 N 4 are presented with special emphasis on the reaction temperature, C:SiO 2 ratio, and precursor mixing. With pure precursors, the conversion temperature is 1500° to 1550°C. An excess of C is necessary for complete conversion, and a simple sol–gelmixing technique provid…
The compound [Me3N(CH2)6NMe3]2[Mo8O26]·2H2O crystallizes from an aqueous solution of sodium molybdate and [Me3N(CH2)6NMe3]Cl2, slightly acidified with hydrochloric acid. The crystals are monoclinic, space group P21/n with a= 12.42(1), b= 12.897(3), c= 15.74(1)Å, β= 106.41(5)° and Z= 2. The structure was determined by…
High-resolution 27Al magic-angle spinning nuclear magnetic resonance spectroscopy (MAS NMR)(78.15 MHz) spectra are reported for commercial and natural gibbsites and materials occurring in the thermal transformation sequences of gibbsite (boehmite; χ, α and ρ-aluminas; calcines produced at 400, 700, 900 and 1000 °C). S…
Abstract Amorphous celluloses were prepared by regeneration of cellulose from its solutions in the SO 2 –diethylamine–dimethylsulfoxide (SO 2 –DEA–DMSO) solvent system, and other selected SO 2 –amine–organic solvents. The celluloses were amorphous whether regenerated in water or in alcohols or other organic solvents;…
Fors soil (Tierp) is classified as an illitic, calcareous, frigid Udic Haploboroll according to the Soil Taxonomy and as a Calcaric Phaeozem in the FAO-system. It is a silty soil consisting of a thick dark brown coloured A-horizon and a subsoil rich in calcium carbonate and bases. Kungsängen soil (Uppsala) is classifi…
Translucent alumina ceramics with extremely high in-line optical transmittance to visible light and high mechanical strength were produced by applying HIP process to a sample which was densified at a relatively low temperature after injection molding. Measurements of bulk density and average grain size, X-ray diffract…
Porphyrin-α-diones can be prepared by photooxidation or SeO2-oxidation of β-hydroxyporphyrins, which are in turn readily synthesized from the corresponding copper(II) or nickel(II) 2-halo- and 2-sulphinyl-porphyrins by reaction with the anion of E-benzaldoxime; the efficient conversion of the porphyrinoquinoxaline 6 i…
The dehydrogenation and dehydration reactions of ethanol over TiO2, ZrO2 or HfO2 catalysts has been monitored in the gas phase and on the surfaces by infrared spectroscopy. The reaction pathways closely parallel those of methanol reported in the prevous paper (Part 2) with the addition of the direct dehydration reacti…
Impact and tensile properties of polypropylene filled with various minerals have been measured. The minerals investigated were dolomite, calcium carbonate, mica and wollastonite. The effect of particle shape, size, content and surface treatment on mechanical properties was studied. A special interest was devoted to th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructure and catalytic activity of alumina-supported platinum-cobalt bimetallic catalysts. 2. Chemisorption and catalytic reactionsLaszlo Guczi, Tamas Hoffer, Zoltan Zsoldos, Souad Zyade, Gilbert Maire, and Francois GarinCite this: J. Phys. Chem. 1991, 95, 2, 802–808Publica…
Investigations to determine the relevant electric and dielectric properties of certain insulating fluids which appeared most suitable from the viewpoint of environmental compatibility and inflammability are discussed. Two of these are silicone fluids based on linear polydimethyl siloxane (kinematic viscosity at 25 deg…
The effects of self-radiation damage due to alpha decay was studied as a function of cumulative decay events in synthetic zircon doped with 238Pu. The density of the Pu-doped zircon decreased exponentially with dose to a value corresponding to a density change of 14.2% at saturation. The initially crystalline material…
The thermal shock behavior of Si 3 N 4 has been determined with a new type of computer‐controlled testing equipment. Thin circular disks are heated up to 1350°C with two tungsten halogen lamps yielding heating rates up to 1000°C/s. The sample temperature is measured in situ with an infrared pyrometer and used to calcu…