Materials Literature
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Porcine ribonuclease inhibitor (RI) contains 30 1/2-cystinyl residues, all of which occur in the reduced form. Reaction of the native protein with 5,5'-dithiobis (2-nitrobenzoic acid) resulted in the release of 30 mol of the product 5-mercapto-2-nitrobenzoate, and the loss of the RNase inhibitory activity. A linear re…
In landfills, deposited waste material is usually faced with strictly anoxic conditions. This means that the design of new biodegradable polymers must take into consideration that degradation should be possible especially in the absence of molecular oxygen. Poly-beta-hydroxybutyrate is depolymerized by the anaerobic f…
The major physical properties of poly(hydroxybutyrate) (PHB) and its copolymers with hydroxyvalerate (PHB/HV) and those of their blends are summarised. Cases of liquid-liquid phase separation in homopolymer copolymer blends are reported and conditions where further phase separation occurs during crystallisation are do…
Sol-gel derived PZT (lead zirconate-titanate) thin films were irradiated to a total-dose of 1 Mrad(Si) or 86 krad(PZT) under open-circuit bias. An asymmetric distortion in the hysteresis curves was observed. The distortion depends on the polarization state of the capacitor before irradiation. Postirradiation electrica…
Abstract Dielectric measurement on a polymer‐dispersed liquid crystal (PDLC) has been carried out in the frequency range from 10 Hz to 1 MHz and over the temperature range from 100 to 330 K. The PDLC sample was prepared by thermally induced phase separation of a 50% mixture by weight of commercially available liquid c…
BaTiO 3 ceramics with grain sizes of 0.6 to 6 mm and relative densities of 89% to 92% were prepared by hot forging and conventional sintering from high‐purity oxalate‐derived powder. The aging of both the dielectric constant and the dielectric loss was examined with respect to grain size, temperature, and frequency. I…
Abstract X‐ray photoelectron spectroscopy was used to characterize the hydroxylated oxide film on iron surfaces. The composition of the films and its transformations for eighteen specimens prepared by ex situ techniques and simulating various conditions of hydroxylated oxide layer formation were examined. A model of h…
The oxidation process of Si 2 N 2 O, prepared by a hot isostatic pressing technique, has been studied by the thermogravimetric method. The oxidation has been performed in oxygen for 20 h in the temperature range 1300° to 1600°C, producing oxide scales of amorphous SiO 2 and α‐cristobalite. The weight gain for T 1350°C…
The magneto-optical, polar Kerr effect of polycrystalline ${\mathrm{CrO}}_{2}$ has been studied in the range 0.8--5 eV. The maximum Kerr rotation amounts to \ensuremath{\Vert}${\mathrm{\ensuremath{\theta}}}_{\mathit{K}}$\ensuremath{\Vert}=0.154\ifmmode^\circ\else\textdegree\fi{} at 3.7 eV. Two different interpretation…
Rhodococcus ruber NCIMB 40126 synthesizes copolyesters (polyhydroxyalkanoates) of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV), containing primarily 3HV monomer units, from a variety of single, chemically unrelated substrates. The 3HV content of the polymer is dependent on the choice of substrate and succinic a…
Theoretical yields of poly-d(−)-3-hydroxybutyrate (PHB) from several carbon sources have been estimated from biochemical pathways leading to PHB. In estimating the yields, a special emphasis is made on recycling (or regeneration) of NADP+ which is the co-substrate of acetoacetyl-CoA reductase, one of three key enzymes…
Ferroelectric Bi 4 Ti 3 O 12 films have been prepared through the sol-gel process from corresponding metal alkoxides, which were chemically modified. The homogeneous films of the Bi 4 Ti 3 O 12 single phase were obtained on Pt substrates by the heat-treatment at 500°C, under optimum conditions of process parameters su…
A boric acid‐stabilized aluminum acetate powder was decomposed to aluminum borate (Al 18 B 4 O 33 ) by calcining at 1000°C. The powder was then ball‐milled, compacted, and fired to temperatures of 1500°, 1600°, and 1700°C for a period of 1 h. The resulting aluminum borate ceramic had a whiskerlike grain morphology, wi…
Abstract The evaluation of the long periods and crystallite lengths of original and pretreated solvent spun cellulose fibres revealed that they consist of about 90% crystalline cellulose in the direction of the fibre axis. In the case of high wet modulus viscose fibres this percentage is only 50–60%. The intensity of…
High-resolution I 4d photoelectron spectra (total instrumental resolution ∼0.06 eV) of seven simple iodine molecules, ICl, IBr, I2, HI, CH3I, CH2I2, and CF3I, have been recorded. Ligand-field splitting (as measured by the asymmetric C20 crystal-field term) splits the 4d3/2 and 4d5/2 lines into a doublet and triplet, r…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA high-nuclearity polyoxoalkoxomolybdate cluster encapsulating a [Na(H2O)3]+ moiety. Hydrothermal synthesis and structure of [Na(H2O)3H15Mo42O109{(OCH2)3CCH2OH}7]7-M. Ishaque Khan and Jon ZubietaCite this: J. Am. Chem. Soc. 1992, 114, 25, 10058–10059Publication Date (Print):…
SiC‐platelet‐reinforced Al 2 O 3 ‐matrix composites were made by three different forming techniques, i.e., slip casting, tape casting, and dry compaction of a granulated powder. All samples were densified with hot pressing at 1650°C and 25 MPa for 0.5 h. The orientation of SiC platelets in the composites was studied b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLuminescence and intramolecular energy-transfer processes in isomeric cyano-bridged rhenium(I)-rhenium(I) and rhenium(I)-ruthenium(II)-rhenium(I) polypyridyl complexesK. Kalyanasundaram, M. Graetzel, and M. K. NazeeruddinCite this: Inorg. Chem. 1992, 31, 25, 5243–5253Publica…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface chemistry of magnesium oxide-supported molybdenum oxide: an in situ Raman spectroscopic studySi Chung Chang, M. Anne Leugers, and Simon R. BareCite this: J. Phys. Chem. 1992, 96, 25, 10358–10365Publication Date (Print):December 1, 1992Publication History Published on…
Abstract Currently, selection of screw configurations as well as the operating conditions for compounding polymer blends with desired morphology in a co‐rotating twinscrew extruder is an art based on experience. In this paper a quenching section of a twin‐screw extruder is described. The section may replace any segmen…