Materials Literature
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The title compounds were obtained by reacting stoichiometric quantities of the corresponding dialkalimonochalcogenide, germanium powder and chalcogen at 1073 K. The four compounds are isostructural, crystallizing in space group C2/c, Z = 4 with K 4 Ge 4 S 10 : a = 15.161(3), b = 15.198(2), c = 8.760(2) Å, ß = 105.36(3…
Abstract We review some recent research developments on structure development during drawing of poly(ethylene terephthalate) film, and we report a study of constant‐load drawing of amorphous PET film at temperatures of 120°C and 132°C, including the effects of redrawing high‐temperature drawn film at lower temperature…
We developed a bistable cholesteric reflective display using a dual-frequency cholesteric liquid crystal. The material exhibits two stable states at zero field: Bragg reflecting planar texture and nonreflecting (weakly scattering) focal conic texture. It can be switched directly from the planar texture to the focal co…
The detailed ordering kinetics in equiatomic CuAu was studied using in situ time-resolved x-ray scattering. A subtle competition between the modulated CuAu II phase and the simple ordered CuAu I phase was found to occur across the CuAu I/CuAu II phase boundary. The correlation between ordering and the tetragonal disto…
This work was directed towards developing a database for the long-term reliability of piezoelectric PZT thin films under both ac and dc electric drive. Under unipolar ac drive, the transverse piezoelectric coefficient, d 31 , exhibited excellent reliability with an increasing d 31 coefficient during cycling due to pro…
Abstract The mechanical properties in complex systems are explained based on the hierarchical structures present in the system. Hierarchical structures designed for specific mechanical responses are best exemplified by examples from biology. Collagen, a main component in soft connective tissues, is organized into hier…
Abstract The high frequency OH-stretching band in micro-Raman spectra of kaolinites consistently exhibits two partly overlapping components with varying relative intensities. These bands, labelled A and Z, are located at ~3700–3690 and 3690–3680 cm -1 , respectively. Band Z displays greater intensity in Raman spectra…
We here report the first recognized natural occurrence of a clay mineral with interstratified carbonaceous material that, in places, approaches graphite in its structural ordering. Using high-resolution transmission electron microscopy (HRTEM), we found that carbonaceous material in an early stage of graphitization oc…
A fine powder of a Gd 2 O 2 S:Pr ceramic containing halogen ions such as F - , Cl - , Br - or I - was synthesized and its properties as a scintillator were examined. By adding F - at a concentration of 0.002–0.003 mole ratio, light output increased to 107% and afterglow decreased to 4% compared with those of nonadditi…
Surface-enhanced Raman spectra of 2,2′-bipyridine molecules adsorbed on rough silver surfaces were obtained. The spectra are interpreted in terms of two adsorbed species, one of which closely resembles the classical [Ag(bipy)2]+ complex. The spectral features of the second adsorbate indicate the existence of 2,2′-bipy…
Abstract Hard elastic samples of linear polyethylene were prepared by melt extrusion at a high velocity of the melt flow and by subsequent annealing of crystallized samples. The deformation behavior of hard elastic samples obtained by annealing of as‐spun samples at different temperatures has been analyzed at uniaxial…
Realizou-se o inventário florístico das diatomáceas cêntricas dos rios da região a ser inundada para construção do reservatório da Usina Hidrelétrica de Salto Caxias, localizado a sudoeste do Estado do Paraná. Amostras planctônicas foram coletadas mensalmente, em 15 estações de coleta, no período compreendido entre ma…
This paper discusses the evolution observed in the field of high performance polymers and tries to forecast the future in different domains. The paper is divided into four sections: 1. From the 1960s to the 21st century. 2. What’s new in chemistry and why? 3. What could be the future for high performance polymers in s…
For mass production of poly(3-hydroxybutyrate) (PHB), high cell density cultures of Ralstonia eutropha were carried out in 2.5-1 and 60-1 fermentors by two fed-batch culture techniques of nitrogen and phosphate limitation. When the nitrogen limitation technique was employed using both an on-line glucose monitoring and…
Multianvil experiments in the model system MgO-Al 2 O 3 -SiO 2 -H 2 O at 680 °C and 5.2-6.0 GPa yield a variety of Mg,Al-rich mineral assemblages containing pumpellyite-type phases. Run products include the assemblages pumpellyite-coesite, pumpellyite-forsterite-orthoenstatite and pumpellyite-10 Å phase. The pumpellyi…
This paper presents an experimental study on needle heating in sewing heavy materials such as upholstery fabrics. In the experiments, infrared (IR) radiometry, high speed line scanning IR radiometry, and high speed IR radiometry are used to obtain thermal images of the needle during sewing. In particular, IR radiometr…
Dilatometric studies were performed on the nematic and isotropic phases of the homologous series of alkyl-cyano-biphenyl liquid crystals CnH2n+1C6H4C6H4. CN for n = 5 to 9. From these studies the coefficient of volume expansion (a) of the liquid crystal is estimated. Using this data a number of thermoacoustic and an h…
By using a combination of high resolution electron microscopy (HREM) and nanoanalytical electron microscopy (EELS-STEM) techniques, the nanoscale evolution of a 5% Pt/Ce 0.8 Tb 0.2 O 2- x catalyst submitted to reduction in pure hydrogen within the 423−1173 K range has been investigated. Fine details about the platinum…
Im Rahmen unserer Untersuchungen zur Reaktivität und zum Synthesepotential von metastabilen Aluminium(I)-halogenidlösungen haben wir Reaktionen dieser Lösungen mit SiCp und GeCp ausgeführt. Dabei konnten neben einem ungewöhnlichen Cluster mit SiAl14-Gerüst, der an einer anderen Stelle beschrieben wurde, die Verbindung…
OBJECTIVE: Due to the thrombogenicity and permanent implant nature of metallic stents, bioresorable synthetic polymers have been proposed for stents and local drug delivery systems. Bioresorbable polyesters like poly(D,L-lactide) demonstrated excellent biocompatibility in various tissues. This paper describes a novel…