Materials Literature
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A generalized Rapini-Papoular-type anchoring energy formula [J. Phys. (Paris) Colloq. 30, C4-54 (1969)] with two coupling constants is established through a second-order spherical-harmonic expansion. Using this formula, we analyze the threshold and saturation properties of twisted nematic devices with unidirectional p…
A structural model of a one-component $\ensuremath{\sigma}$-phase crystal has been constructed by means of molecular dynamics simulation. The phonon dispersion curves and the vibrational density of states were computed for this model. The dependence of the vibrational properties on the thermodynamical parameters was i…
The ionic model is shown to give a good description of most inorganic materials, such as salts, ceramics, and minerals, regardless of the covalent or ionic character of their bonds. The virtue of the model is its ability to treat chemical bonding using simple electrostatic theory, all the quantum mechanical effects be…
A chiral photochromic polyisocyanate was incorporated into a solid polymer matrix of poly(methyl methacrylate) (PMMA), yielding an isotropic polymer film. Isomerization of the chiral photochromic azo side groups (cis-trans) triggers a reversible conformational change of the helical polyisocyanate backbone. Thus the ch…
The structure of an Al-Ni-Co decagonal quasicrystal (called the S1-type superstructure), which shows diffraction patterns with superlattice reflections, has been studied by atomic-scale observations of electron microscopy. The structure of the decagonal quasicrystal can be characterized as an ordered arrangement of tw…
The mixed-valent indium chalcogenides InTe, In 4 Se 3 , In 4 Te 3 , In 6 S 7 and In 6 Se 7 were studied together with b-In S 3 and TlInS 2 by In and Te K-edge EXAFS spectroscopy. These well-characterized crystalline solids were chosen as model systems to assess the general applicability of EXAFS for structural studies…
Abstract The reactions of trans(N)-[Co(d-pen-N,O,S)2]− with AuI or AgI in water led to the formation of novel S-bridged CoIII3M3 hexanuclear metallacycles [M3{Co(d-pen-N,O,S)2}3] (M = AuI (1), AgI (2)), in which [Co(d-pen-N,O,S)2]− units adopt a trans(O) geometry. The molecular structure of 1 was determined by X-ray c…
Alasan, the exocellular polymeric emulsifier produced by Acinetobacter radioresistens KA53 was shown to bind to the surface of Sphingomonas paucimobilis EPA505 and Acinetobacter calcoaceticus RAG-1. The presence of alasan on the surface of S. paucimobilis EPA505 and A. calcoaceticus RAG-1 caused a decrease in their ce…
The characteristics of the deformation bands (DBs), formed in cyclically deformed copper single crystals with various orientations, were summarized systematically. The formation mechanism of DBs was also explored. It was shown that the appearance of DBs seems to be a general phenomenon in cyclically deformed copper si…
Two pathways for cysteine biosynthesis are known in nature; however, it is not known which, if either, the Archaea utilize. Enzyme activities in extracts of Methanosarcina thermophila grown with combinations of cysteine and sulfide as sulfur sources indicated that this archaeon utilizes the pathway found in the Bacter…
Sol−gel processing of a multilayered film formed by the alternate adsorption of poly(diallyldimethylammonium chloride) and a synthetic silicate sheet mineral, Laponite RD, resulted in an interpenetrating composite network. Kinetic data indicate that the amount of material added due to sorption and gelation of tetraeth…
The present contribution summarizes the most recent results on the synthesis and chemical physical characterization of the new classes of porphyrazine macrocycles having annulated five- and seven-membered heterocyclic rings, i.e. tetrakis(thiadizole)porphyrazine, TTDPzH 2 , tetrakis(selenodiazole)porphyrazine, TSeDPzH…
Posiva Oy has carried out site characterisation for the final disposal of spent nuclear fuel in Finland since 1987. To meet the demanding needs to measure the hydraulic parameters in bedrock Posiva launched development of new flowmeter techniques including measuring methods and equipment in co-operation with PRG-Tec O…
Corrosion of ASTM Grade 2 Ti in alkaline peroxide environments was studied by a combination of experiments utilizing weight loss measurements, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), and potentiodynamic polarography. A corrosion mechanism was proposed, based on peroxide conc…
Porphyrins participate as dienophiles in Diels-Alder reactions with ortho-quinodimethanes or pentacene. They can also behave as dipolarophiles in 1,3-dipolar cycloadditions with a range of 1,3-dipoles. These two reaction types were successfully used to synthesize novel chlorins, bacteriochlorins and isobacteriochlorin…
The dealloying of β-brass in 0.5 M aqueous NaCl was studied by electrochemical techniques at different temperatures in the range 278 K ≤ T ≤ 318 K, complemented with in situ scanning tunneling microscopy (STM) imaging. In the potential region where the electrodissolution of zinc and the formation of vacancies and copp…
Critical settings and their effects on the properties of open-end cover spun yams produced by a novel system are explained. The yams are constructed from open-end rotor spun (OER) yarns and textured polyester yarns combined within the yarn formation zone of the rotor during the open-end rotor spinning process. The end…
The antiferroelectric liquid crystal (AFLC) under investigation possesses different helical polar phases. Measurements of pyroelectric response of these phases as a function of temperature and bias field have elucidated the ability of this method for investigating the nature of antiferroelectric phases and phase trans…
Grain-boundary grooving has been studied on polished surfaces of polycrystalline tungsten annealed at 1350°C. Atomic force microscopy images were taken in the same area for each groove after different annealing times. Secondary oscillations next to the main groove maxima (predicted for grooving by surface diffusion) w…
Typical measurements of macromolecular crystal mosaicity are dominated by the characteristics of the X-ray beam and as a result the mosaicity value given during data processing can be an artifact of the instrumentation rather than the sample. For physical characterization of crystals, an experimental system and softwa…