Materials Literature
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The synthesis of low molecular weight ( M̄ n (NMR) < 27 000 g/mol) lactic acid polymers by condensation polymerization of l -lactic acid was investigated. All polymerizations were carried out in the melt, using different catalysts and polymerization temperatures. The products were characterized by DSC, GPC, titrimetri…
Single crystals of bacterial poly[( R )-3-hydroxybutyrate] (P(3HB)) with different molecular weights ( M n = 2500 and M n = 48 000) were prepared in a mixture of chloroform and ethanol. The enzymatic degradation of P(3HB) single crystals with extracellular PHB depolymerase purified from Pseudomonas stutzeri YM1006 was…
The synthesis of peroxo−citrato−niobium, a novel aqueous precursor of niobium, is reported. Niobium oxalate was decomposed with acidified H 2 O 2 to form a peroxo−niobium complex, which was reacted with citric acid at pH ∼ 7.5 to form the stable peroxo−citrato−niobium complex. IR and Raman spectroscopy indicate that t…
A novel Ni‐YSZ cermet anode for solid oxide fuel cell application has been developed in order to solve problems with our previous anode, which was prepared from a powder mixture of NiO and precalcined YSZ. In contrast to homogeneously sized YSZ in our previous anode, the new material has a YSZ frame made of coarse (av…
Abstract The effect of pH on the decomposition of peracetic acid in an aqueous solution was studied. It was found that three potential reactions, namely i) the spontaneous decomposition, ii) the hydrolysis and iii) the transition metal catalysed decomposition, are responsible for the consumption of peracetic acid. The…
Immunofluorescence labeling, using a monoclonal antibody developed against actin, revealed the relative abundance and rearrangements of F-actin arrays which occur in cells of the maize root apex as they make the developmental transition from proliferative growth in the meristem to a non-proliferative state in more mat…
A new phosphorus-containing oxirane bis-glycidyl phenylphosphate (BGPP), and a diamine, bis(4-aminophenyl)phenylphosphate (BAPP), were synthesized. Both of these two phosphorus-containing compounds lead to phosphate-containing epoxy resin via curing reaction. The kinetics of the curing reaction of BGPP with various cu…
The nickel(I) and nickel(II) complexes of 5,20-bis(p-tolyl)-10, 15-diphenyl-21-oxaporphyrin (ODTDPPH) and 5,10,15,20-tetraphenyl-21, 23-dioxaporphyrin (O2 TPP) have been investigated. These oxa analogues of 5,10,15,20-tetraarylporphyrin, where one or two pyrrole rings are replaced by a furan moiety, have been synthesi…
In this study, we examine the oxygen isotope ratios of smectite and kaolinite in a stratigraphic sequence of paleosols in the Siwalik Himalayan molasse on the Potwar Plateau, northern Pakistan. There is a 3–4%o increase in the smectite δ18O values synchronous with a ∼ 3.5%o increase in δ18O values of pedogenic calcite…
Extension of the π-system of 1,6,7,12-tetrakis(aryloxy)-3,4,9,10-perylenetetracarboxdiimide was achieved by the condensation of 1,6,7,12-tetrakis(aryloxy)-3,4,9,10-perylenetetracarboxylic bisanhydride with 1,2-diaminobenzene, 1,8-diaminonaphthalene, and 9,10-diaminophenanthrene. A full characterization of the resultin…
The true stress−strain characterization of the tensile yield as a function of temperature and cross-head speed is reported for three ethylene−butene copolymers having different crystal weight fractions in the range 0.66−0.35. Evidence is given of two plastic processes operating competitively depending on the experimen…
The demand for actuators featuring biomimetic properties, such as linearity, high power density and compliance, is growing in microrobotics and bioengineering. In the present paper a novel linear actuator is presented. It exploits the electromechanochemical phenomena of -electron conjugated conducting polymers, occuri…
Electron spin resonance (ESR) experiments in the paramagnetic phase of ${\mathrm{R}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{B}}_{\mathrm{x}}$${\mathrm{MnO}}_{3+\mathrm{\ensuremath{\delta}}}$n(R=La,Pr; B=Ca,Sr) show, for 1.1 ${\mathrm{T}}_{\mathrm{C}}$\ensuremath{\lesssim}T\ensuremath{\lesssim}${2\mathrm{T}}_{\…
The preparation and crystal structures of the n = 2 Ruddlesden−Popper phases Sr 2 - x Ln 1+ x Mn 2 O 7 (0 ≤ x ≤ 0.5, Ln = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Y, and Er) are described. The crystal chemistry and stability of this structure is governed by the size of the lanthanide cation. Partial ordering of the Sr 2+ a…
Abstract Numerous examples in the literature illustrate how the coextrusion of film with three or more polymeric layers is economically used to achieve a desirable mix of end‐use characteristics. More recently, layer‐multiplying devices permit two polymers of widely dissimilar solid‐state properties to be combined int…
A new type of disc-shaped molecule (1 a-c) has been synthesised and characterised. The molecules were built up by linking three lipophilic, N-monoacylated 2,2'-bipyridine-3,3'-diamine wedges to a central 1,3,5-benzenetricarbonyl unit. They show liquid crystalline behaviour, as shown by DSC, polarisation microscopy and…
Other| February 01, 1997 Structural behavior, crystal chemistry, and phase transitions in substituted leucite: High-resolution neutron powder diffraction studies David C. Palmer; David C. Palmer University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom Search for other works by this author on: G…
Nearly monodisperse CdSe nanoclusters, surface-passivated with a layer of trioctylphosphine and trioctylphosphine oxide, have been sequestered within phosphine-containing domains in a diblock copolymer. A convergent approach to fabrication of these composites was adopted via independent synthesis of nanoclusters and p…
Abstract Rehydration is shown to be straightforward for the reconstruction of polyoxometallate-pillared layered double hydroxides. Zn-Al hydrotalcite-like minerals were prepared with Zn/Al ratios of 1 to 5 by coprecipitation at pH 7. Good crystallinity was obtained for samples with Zn/Al ratios above 2. Thermal decomp…
A straightforward and very efficient pathway has been reported for the synthesis of a functional derivative of ε-caprolactone, i.e. 5-ethylene ketal ε-caprolactone. This new monomer has been homopolymerized and copolymerized with ε-caprolactone in a well-controlled manner, strongly suggesting absence of any side react…