文献浏览

Patente / Patents

Extruder im Vergleich / Extruders compared

Rheologische Strömungen numerisch betrachtet / A numerical view of rheological flow

Probleme / Problems

Brevier/Brevier

Natural and artificial ageing for evaluating waterproofing treatments for marble

Exposure of samples to artificial ageing is commonly carried out to test the durability of natural and artificial stones and the effectiveness of products used for their conservation. Correlations between artificial and natural ageing, however, are not always well understood mainly because the former can only try to s…

Inhalt / Contents

Ticker / Ticker

Critical-point phonon frequencies of diamond

The phonon-dispersion curves derived from neutron-scattering experiments performed on diamond [J. Warren et al., Phys. Rev. 158, 805 (1967)] are not accurate enough to yield the exact frequencies of critical-point (CP) phonons and, thus, to provide a satisfactory interpretation of second-order optical spectra. A self-…

Physical Stabilization of the β → γ Transformation in Dicalcium Silicate

It has been shown that the monoclinic β ‐phase of dicalcium silicate (Ca 2 SiO 4 ) can be stabilized against transformation to the orthorhombic γ ‐phase by physical rather than chemical factors. Stabilization was studied in different types of microstructures fabricated under various processing conditions such as diffe…

Numerical treatment of progressive localization in relation to borehole stability

Abstract Results of large‐scale finite element computations are presented for the problem of borehole failure due to the high stresses at great depths. Rock is modelled by an extension of the Mohr–Coulomb flow theory of plasticity for material with Cosserat micro‐structure. The introduction of internal length (grain s…

Single-crystal X-ray structure study of synthetic pyrope almandine garnets at 100 and 293 K

The crystal structures of synthetic pyrope (Mg3AI2Si3012),almandine (FeAI2Si3012), and the solid-solution garnet compositions PY8o-Alm2o, PY6o-Alm4o, and PY2o-Alm8o have been refined in space group Ia1d from high-precision X-ray diffraction data with sin 0/>..> 0.4 A-I measured at 100 and 293 K. There is no indication…

XPS study of passive films formed on molybdenum‐implanted austenitic stainless steels

Abstract Austenitic stainless steels (Fe–19Cr–10Ni (at.%)) have been implanted with molybdenum ions (Mo + , 100 keV, 2.5 × 10 16 atoms cm −2 ). The implanted material has been characterized by XPS and RBS. The implanted region has a thickness of ∼1000 Å with a maximum molybdenum concentration of ∼9 at.% Mo located at…

Coordination compounds of polyoxovanadates with a hexametalate core. Chemical and structural characterization of [VV6O13[(OCH2)3CR]2]2-, [VV6O11(OH)2[(OCH2)3CR]2], [VIV4VV2O9(OH)4[(OCH2)3CR]2]2-, and [VIV6O7(OH)6](OCH2)3CR]2]2-

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCoordination compounds of polyoxovanadates with a hexametalate core. Chemical and structural characterization of [VV6O13[(OCH2)3CR]2]2-, [VV6O11(OH)2[(OCH2)3CR]2], [VIV4VV2O9(OH)4[(OCH2)3CR]2]2-, and [VIV6O7(OH)6](OCH2)3CR]2]2-Qin Chen, David P. Goshorn, Charles P. Scholes,…

Reduction of fibrinogen adsorption on PEG‐coated polystyrene surfaces

Reduction of protein adsorption by coating surfaces with polyethylene glycol (PEG) is well documented. The present work has four goals related to these previous studies: first, to develop chemistry providing densely packed, covalently bound PEG on polystyrene (PS); second, to determine the ability of these modified su…

Chemistry of illite-smectite inferred from TEM measurements of fundamental particles

Abstract Mixed-layer illite-smectites (I-S) have a stable charge on the illite interlayer equal to 0·89/O 10 (OH) 2 , as shown by electron microscope measurements of mean fundamental particle thickness, using both Pt-shadowing and high-resolution techniques. This has been verified by independent measurements of total…

LSI- a computer program for simultaneous refinement of material structure and microstructure

A computer program has been written to introduce profile analysis into the Rietveld method. The devised algorithm simultaneously refines both structural and microstructural parameters, also accounting for anisotropy in crystallite size and microstrain. Instead of using phenomenological relations to describe the trend…

Two-step spin crossover in the new dinuclear compound [Fe(bt)(NCS)2]2bpym, with bt = 2,2'-bi-2-thiazoline and bpym = 2,2'-bipyrimidine: experimental investigation and theoretical approach

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo-step spin crossover in the new dinuclear compound [Fe(bt)(NCS)2]2bpym, with bt = 2,2'-bi-2-thiazoline and bpym = 2,2'-bipyrimidine: experimental investigation and theoretical approachJose Antonio Real, Helene Bolvin, Azzedine Bousseksou, Ary Dworkin, Olivier Kahn, Franco…

A Unified Model for the Low-Energy Vibrational Behaviour of Amorphous Solids

The anomalous low-energy vibrational behaviour exhibited by amorphous solids (a peak in the vibrational density of states, in C v / T 3 and in the Raman spectrum–the boson peak–and a plateau in the thermal conductivity) is ascribed to the phonon scattering caused by intrinsic density fluctuation domains in the structu…

Palladium catalysis of O2 reduction by electrons accumulated on TiO2 particles during photoassisted oxidation of organic compounds

Our earlier theoretical analysis suggested that the quantum efficiency of photoassisted oxidation of organic compounds in water by O2 on n-TiO2 surfaces can be limited by the kinetics of the reduction of O2. When the rate of O2 reduction is not sufficiently fast to match he rate of reaction of holes, an excess of elec…