Materials Literature
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Non-axenic unialgal cultures of eleven marine diatoms were screened against 13 pathogenic bacteria and 8 pathogenic fungi by agar disc diffusion method. The lipophilic and aqueous extracts of 6 diatoms which showed high antibacterial activity were separately screened against the same bacterial strains and two diatoms…
Pressureless‐sintered TiO 2 ‐excess BaTiO 3 (BT) ceramic doped with Na 2 O (as an acceptor oxide) has been investigated for the inhibition of platelike (111) twin grains and the associated microstructure development. Solid‐state reaction between the Na 2 O dopant and the excess TiO 2 of the nonstoichiometric BaTiO 3 p…
Titanium rich alloys of the Ti–Al–C system have been investigated to determine the constitution in the range 1250–750°C with particular reference to phase equilibria and transformations involving TiC and Ti3AlC (P phase). Alloys with varying aluminium and carbon concentrations up to 15 at.-%Al and 15 at.-%C have been…
Elastic modulus (Young's modulus M and shear modulus G ) and internal friction Q -1 are measured as a function of temperature from -180°C to 500°C in undoped lead zirconate titanate (PZT) ferroelectric ceramics in the range of kHz and low frequencies (0.1 to 1 Hz). New phase transition temperatures at the morphotropic…
Multicolor fluorescent liquid crystal displays (LCDs) are proposed. The twisted nematic (TN) cell containing a dichroic fluorescent dye is utilized as a UV shutter, a polarization switch and an active emitter. We describe two fluorescent LCD modes of different stacking order of the fluorescent TN cell, alternative flu…
The use of depleted uranium dioxide (DUO2) particulates as fill material for repository waste packages (WPs) containing light-water reactor (LWR) spent nuclear fuel (SNF) was investigated. A repository WP would be loaded with SNF, and small DUO2 particulates (0.5 to 1.0 mm) would be added to fill the void space inside…
The double-bridged tetraselenafulvalenophanes (TSF-phanes, 4) were efficiently synthesized by a new method using the deprotection/realkylation sequence of the TSF bisthiolate building block 7. Electrocrystallization of 4b with the Au(CN)2− counter-anion gave a radical cation salt that showed a very high conductivity o…
Abstract Recent years have seen a growing interest in the direct and indirect roles of organisms, and more explicitly of organic matter, in the crystallization of minerals in sediments. Two bivalve genera form extensive biofilms that are apparently responsible for the growth of a variety of isolated crystals together…
A study is reported of the dependence of the TiSe 2 lattice constants on the concentration of an intercalated metal in various valence states and external pressure. The strain energy and the polaron shift created in the intercalation of TiSe 2 with metals in various valence states have been determined. The position of…
A new qualitative mechanism of pore nucleation and initial stages of porous silicon ( por -Si) growth was proposed. The emphasis was on the charge exchange between Si 2+ ions generated by electrolytic or chemical oxidation of initial silicon (disproportionation reaction). The mechanism eliminates, to a large extent, t…
A previously unreported defect, which is labeled $O3,$ has been observed in the EPR spectrum of synthetic type-IIa diamonds irradiated at 100 K with 2 MeV electrons. This defect was not observed in identical diamonds whose temperature during electron irradiation was \ensuremath{\geqslant}300 K. This center has also be…
A two-dimensional mathematical model for vacuum-contact drying of wood is presented. The moisture and heat equations are based on the water potential concept whereas the pressure equation is formulated considering unsteady state conservation equation of dry air. Most of the model parameters were determined during inde…
Photosynthetic organisms inhabiting the caves of Frasassi (Italy) were identified and aspects of their strategy of acclimation to the cavern environment investigated. The habitats of the organisms were characterized with special reference to light, the inorganic carbon system and the availability of inorganic N, P and…
The support–overlayer adsorptive interactions, generated when solutions of Anderson heteropolyoxomolybdates were supported as a monolayer on γ-Al 2 O 3 by means of the equilibrium adsorption method, were studied by XRD analysis, DR spectroscopy, electron microscopy (SEM–EDAX) and TPR methods. The adsorption isotherms…
The reaction by which kaolinite transforms to I-S has been studied by SEM and TEM using core samples from the Salton Sea Scientific Drilling Project. Kaolinite is abundant from the surface to a depth of ∼300 m (∼115°C), decreasing in abundance and becoming undetectable at a depth of ∼500 m (∼160°C), with a concomitant…
The effects of Fe doping in ${\mathrm{La}}_{0.67}{\mathrm{Sr}}_{0.33}{\mathrm{CoO}}_{3}$ has been studied by the measurements of magnetic, electrical transport, and magnetoresistance properties. It is found that no apparent structure change is introduced by Fe doping up to $x=0.3.$ But the Curie temperature ${T}_{c}$…
Four previously unknown n-C25 and n-C27 heptaenes of the marine diatom Rhizosolenia setigera were isolated and identified using NMR spectroscopy. They possess six methylene interrupted (Z)-double bonds starting at C-3 and an additional terminal or n-2 (Z)-double bond. Structural and stable carbon isotopic evidence sug…
This paper describes the effect of substituent and ester linkage on smectic properties for some derivatives of 4-R -phenyl 4-(4-octyloxybenzoyloxy)benzoates (1), 4-octyloxyphenyl 4-(4-R-benzyloxy)benzoates (2), 4-(4-octyloxybenzoyloxy)phenyl 4- R -benzoates (3), and 4-R-phenyl 4-octyloxyphenyl terephthalates (4) where…
CYP119 is a cytochrome P450 with a molecular weight of 43 kDa which has been isolated from the thermophilic archaeon Sulfolobus solfataricus. This enzyme is extremely stable to high temperature and high pressure. The first crystallization and preliminary crystallographic study of CYP119 is reported here. Crystals of C…
Structures of various phases that appear in antiferroelectric liquid crystals can be described within a simple discrete phenomenological model of antiferroelectric liquid crystals, which for the smectic-C-alpha (SmC(alpha)) phase suggests a short-pitch helicoidal structure. In a paper presented here the same model is…