Materials Literature
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Modified segmented polyurethanes were examined for biostability and biocompatibility using an in vivo cage implant system for time intervals of 1, 2, 3, 5, and 10 weeks. Two types of materials were used: polyether polyurethanes and polycarbonate polyurethanes. Two unmodified polyether polyurethanes (PEUU A' and SPU-PR…
Raman-scattering and far-infrared-transmission spectra of hexagonal ${\mathrm{YMnO}}_{3}$ (space group ${P6}_{3}cm)$ are reported and discussed. In the Raman spectra measured in several exact scattering configurations, lines of ${A}_{1}$ (at 148, 190, 257, $\ensuremath{\sim}300$, 433, 459, and 681 cm${}^{\ensuremath{-…
Certain newly discovered characteristics of natural biopolymers should make them a choice material to be used for different types of wrappings and films. Edible and/or biodegradable packagings produced from agricultural origin macromolecules provide a supplementary and sometimes essential means to control physiologica…
Abstract New low molecular weight gelators based on the structure RNHCONHXNHCONHR have been synthesized and tested for their ability to cause gelation of organic solvents. Compounds 2 (R = n ‐dodecyl, X = ‐(CH 2 ) 9‐ ), 3 (R = n ‐dodecyl, X = ‐(CH 2 ) 12‐ ), 4 (R = n ‐dodecyl, X = 4, 4′‐biphenyl), and 5 (R = benzy…
Diffusion of Li and Na ions in TiO 2, anatase, has been studied using theoretical (quantum chemical ab initio periodic Hartree−Fock and a modified semiempirical INDO) as well as electrochemical (chronocoloumetry) methods. On the basis of the theoretical calculations, the geometry of equilibrium and transition states f…
Various forms of damage were observed in pressure‐less‐sintered Al 2 O 3 /ZrO 2 symmetric laminates and asymmetric laminates (bilayers) fabricated by tape casting and lamination. These defects included channel cracks in the ZrO 2 layers, Al 2 O 3 edge‐effect cracks parallel to the layers, delamination in the Al 2 O 3…
The limiting reduction and oxidation potentials and electrolytic conductivities of new quaternary ammonium salts were examined for electrochemical capacitor applications, whose anions have already been tested as lithium salts for lithium battery applications. The anodic stability was in the following order The electro…
Abstract This paper compares mechanisms of the reaction of smectite to illite, in light of structural models for interstratified illite/smectite (I/S). The crystal structure of I/S has been described previously by a nonpolar and polar 2:1 layer model. In a nonpolar model, individual 2:1 layers are chemically homogeneo…
Abstract Proceeding from the α‐ B ‐SbW 9 O 33 fragment 1 , various novel large heteropolyanions ([Na 2 Sb 8 W 36 O 132 (H 2 O) 4 ] 22– ( 2 ), [Sb 2 W 22 O 74 (OH) 2 ] 12− ( 3 ) and [Sb 2 W 20 M 2 O 70 (H 2 O) 6 ] (14−2 n )− ( 4 ); M n + = Fe 3+ , Co 2+ , Mn 2+ , Ni 2+ ) have been obtained in crystalline form by system…
Physical properties of thermotropics basic nonlinear optics light-induced reorientation thermal effects linear and nonlinear optical properties of PDLC.
The crystal structure of the closed form of citrate synthase, with citrate and CoA bound, from the hyperthermophilic Archaeon Pyrococcus furiosus has been determined to 1.9 A. This has allowed direct structural comparisons between the same enzyme from organisms growing optimally at 37 degrees C (pig), 55 degrees C (Th…
A 5.0-kbp EcoRV-EcoRI restriction fragment was cloned and analyzed from genomic DNA of Aeromonas caviae, a bacterium producing a copolyester of (R)-3-hydroxybutyrate (3HB) and (R)-3-hydroxyhexanoate (3HHx) [P(3HB-co-3HHx)] from alkanoic acids or oils. The nucleotide sequence of this region showed a 1,782-bp poly (3-hy…
Nanosized amorphous NiFe 2 O 4 powder was prepared by sonochemical decomposition of solutions of volatile organic precursors, Fe(CO) 5 and Ni(CO) 4, in decalin at 273 K, under an oxygen pressure of 100−150 kPa. The amorphous nature of these particles was confirmed by various techniques, such as SEM, TEM, electron micr…
We describe the preparation and structural characterization of carbon-supported Pt−Ru nanoparticles with exceptionally narrow size and compositional distributions. The supported bimetallic particles are obtained by reduction of the neutral molecular carbonyl cluster precursor PtRu 5 C(CO) 16 with hydrogen. A detailed…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorPreparation of Hyperbranched Polyacrylates by Atom Transfer Radical Polymerization. 1. Acrylic AB* Monomers in "Living" Radical PolymerizationsKrzysztof Matyjaszewski, Scott G. Gaynor, Anthony Kulfan, and Matthew PodwikaView Author Info…
In order to describe the thermomechanical properties in shape memory polymer of polyurethane series, a thermomechanical constitutive model was developed by modifying a standard linear viscoelastic model. The model involved a slip element due to internal friction and took account of thermal expansion. In order to descr…
We present experimental support for a model of abalone nacre growth that is based on mineral bridges between successive aragonite tablets rather than on heteroepitaxial nucleation. Interlamellar sheets of organic polymers delineate the aragonite tablets but allow the tablets to grow mineral bridges through pores in th…
The influence of the simplifications introduced by modeling a molecular structure on the exchange coupling constant is studied for hydroxo-bridged Cu(II) binuclear complexes. This study focuses on the role of the terminal ligands and the counterions. The terminal ligands are responsible for marked changes in the excha…
▪ Abstract Scintillators are the primary radiation sensor in many applications such as medical diagnostics, medical radiographs, and industrial component inspection. Some of the limitations in the properties of single-crystal scintillators are discussed for imaging applications, and the advantages of a new class of po…
The magnetic properties of ruthenates with perovskite-derived structures, particularly ${(\mathrm{C}\mathrm{a},\mathrm{S}\mathrm{r})\mathrm{RuO}}_{3}$ and ${\mathrm{Sr}}_{2}{\mathrm{YRuO}}_{6}$, are studied within the context of band-structure-based Stoner theory. First principles calculations are used to demonstrate…