Materials Literature
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A micromechanically based model for the deformation, strength, and stress‐rupture life of a ceramic‐matrix composite is developed for materials that do not degrade by oxidative attack. The rupture model for a unidirectional composite incorporates fiber‐strength statistics, fiber degradation with time at temperature an…
This article reports on the ecological preferences of benthic diatoms in relation to pH, conductivity and organic pollution-eutrophication and their tolerance spectrums. Three Pampean streams subjected to different human impacts were studied. The bottom substrate of these streams is mostly composed of slime-clay with…
Some properties of electron field emitters based on various types of carbon are difficult to measure and are not well known. This is particularly true for amorphous carbon films, for nanotubes and for nanotips grown by carbon contamination in a scanning electron microscope. We show that by combining together experimen…
Results of spin-polarized, gradient-corrected, periodic density functional theory calculations are reported for the dissociative adsorption of molecular oxygen over the oxide surface of La 2 O 3 (001). The diatomic surface oxygen species formed from O 2 dissociation are characterized structurally by a bent orientation…
This paper reports on the full electrochemical synthesis of electrically conducting polymers chemically grafted to conducting surfaces (e.g., glassy carbon, stainless steel, nickel, gold). It is based on new functional acrylate monomers, i.e., 3-(2-acryloyloxyethyl)thiophene and N -(2-acryloyloxyethyl)pyrrole, whose t…
Using STM, we have directly confirmed the incommensurate stacking of double atomic layers of graphene and monolayer h-BN on Ni(111). The formation of a graphene layer weakens the interfacial interaction between monolayer h-BN and Ni(111), resulting in insulating h-BN layers, while a pristine monolayer h-BN on Ni(111)…
We provide a detailed analysis of the various problems connected with the development of tunable thin-film filters for wavelength-division multiplexing applications. We examine the relation between the change in layer thickness and the central wavelength shift for various configurations and point out the significance…
Transient photovoltage (PV) measurements have been carried out on free-standing porous silicon of different porosity. For porous silicon of low porosity, fast charge-carrier separation takes place in the surface space-charge region. A retarded component arises in the PV transients due to limitation of the separation o…
Abstract— Fringe‐field‐switching (FFS) devices using liquid‐crystal (LC) with a negative dielectric anisotropy exhibit high transmittance and wide viewing angle simultaneously. Recently, we have developed an “Ultra‐FFS” thin‐film‐transistor (TFT) LCD using LC with a positive dielectric anisotropy that exhibits high tr…
Detailed tribological studies on diamond and diamond-like carbon (DLC) films have confirmed that these films are inherently self-lubricating and resistant to abrasive, adhesive and corrosive wear. Because of their high chemical inertness, they are also resistant to corrosion and oxidation (even at elevated temperature…
Abstract Three popular 100% cotton knitted fabrics, (plain single-jersey, 1x1 rib and interlock) were subjected to five cycles of four different washing and drying regimes. This was in order to investigate the effect of laundering with detergent as opposed to water, and tumble drying against line drying. The main aim…
This unit describes the preparation of conjugates between nanometer-scale gold particles and synthetic oligonucleotides. Oligonucleotide-functionalized gold nanoparticles are finding increased use in both the construction of complex, tailored nanostructures and the optimization of DNA sequence analysis. The protocols…
Abstract Bentonite samples from Choushan treated at various acid concentrations were studied using chemical analysis, XRD, 29 Si and 27 Al MAS NMR to investigate the microstructure of the activated montmorillonites. Two types of structural units were formed during the activation: (1) (SiO) 3 SiOH, in which up to 15% o…
Tagatose-1,6-bisphosphate aldolase (TBPA) is a tetrameric class II aldolase that catalyzes the reversible condensation of dihydroxyacetone phosphate with glyceraldehyde 3-phosphate to produce tagatose 1,6-bisphosphate. The high resolution (1.45 A) crystal structure of the Escherichia coli enzyme, encoded by the agaY g…
Abstract Mechanical properties of linear thermoplastic polyurethanes (TPUs) prepared by polyaddition reaction using a polycarbonate diol (PCD), 1,4‐butanediol (a chain extender) and 4,4'‐diphenylmethane diissocyanate were investigated. Chemical composition among these three components was kept constant. Primary attent…
Abstract In this work, we have studied the effects of extrusion die design, resin molecular structure, and lubricant concentration on the properties of PTFE paste extrudates by performing macroscopic extrusion pressure measurements, Raman spectroscopy, differential scanning calorimetry and mechanical testing on the ex…
The results obtained from a study on the microstructure and the electrical properties of Gd‐doped CeO 2 thin films were reported. Dense, nanocrystalline films on sapphire substrates are prepared using a polymeric precursor spin coating technique. The electrical conductivity was studied as a function of temperature and…
Electron and positron energy levels and deformation potentials are calculated in III–V bulk cubic nitrides using the pseudopotential formalism and the independent particle model. The calculated electron deformation potentials are found to be in reasonable agreement with the available data in the literature, whereas ou…
Abstract An Fe-rich smectite from Ölberg (Germany) was characterized using X-ray diffraction, infrared spectroscopy and analytical electron microscopy. Progressive reduction of the octahedral charge was performed through the Hofmann & Klemen effect at increasing temperatures. The sample was heterogeneous, consisti…
In vitro evolution was applied to obtain highly active mutants of Ralstonia eutropha polyester synthase (PhbC(Re)), which is a key enzyme catalyzing the formation of polyhydroxybutyrate (PHB) from (R)-3-hydroxybutyryl-CoA (3HB-CoA). To search for beneficial mutations for activity improvement of this enzyme, we have co…