Materials Literature
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A series of P=S-containing dendrimers (starburst macromolecules) were characterized by X-ray photoelectron spectroscopy (XPS). This technique is a unique tool for the identification of specific groups from these starbursts such as P=S, aromatic rings, C–O, and C=O. Surface elemental and chemical composition is found t…
The influence of a polymer network, stabilizing an initial texture of horizontal chevron geometry, on the in-plane smectic C* layer reorientation process is studied for different applied electric field conditions. As expected, the reorientation of smectic layers is strongly slowed down and eventually suppressed by the…
In order to study the mechanism of DC offset voltage generation in a hybrid-aligned nematic liquid crystal display (HAN-LCD), we theoretically and experimentally studied the electrooptic characteristics of a HAN sample. The results showed that decreasing the thickness of a LC alignment film strongly reduces the genera…
Abstract We demonstrate control over the orientation of the 4,4′‐bis(2,3‐epoxypropoxy)‐α‐methylstilbene (EPAMS)/sulfanilamide (SAA) epoxy system. A statistical experimental design was generated and analyzed to determine the effects of the time in the magnetic field, field strength, and the amount of B‐staging. A regre…
Chiral-nematic glassy liquid crystals (GLCs) are of interest because of their unique supramolecular structure and associated optical properties. However, the constant-pitch films produced so far have a bandwidth limited to less than 100 nm in the visible. The introduction of a pitch gradient, indicated by theory to in…
In this study, the microstructure of injection-molded polypropylene reinforced with cellulose fiber was investigated. Scanning electron microscopy of the fracture surfaces and X-ray diffraction were used to investigate fiber orientation. The polypropylene matrix was removed by solvent extraction, and the lengths of th…
Abstract The effect of coupling agents and filler particle size on melt rheology of poly(phenylene sulfide)‐bonded neodymium‐iron‐boron (Nd‐Fe‐B) alloy magnets was studied with oscillatory flow experiments to accelerate efforts to optimize their processing. The minimum viscosity of the polymer‐bonded magnets near 290°…
Trinuclear CuIIPtCuII complexes (see scheme) are formed with four bridging 1-methylcytosinate nucleobases. These compounds are diamagnetic as a result of the strong exchange interaction (J≅1000 cm−1 (2 b)), despite a separation of approximately 5 Å between the CuII centers.
The microstructure, crystal phase, electrical conductivity, and mechanical strength of less than 7‐mol%‐Sc 2 O 3 ‐doped zirconia ceramics fabricated by comparatively low‐temperature sintering at 1200–1300°C for 1 h were investigated. Zirconia ceramics having a uniform microstructure (grain size < 0.5 μm) stabilized…
Polyaniline (PA) and aniline black (AB) were prepared in powder form by the chemical method of oxidative polymerization, from which free-standing thin films were obtained by solvent evaporation using N-methyl pyrrolidinone ( NMP ). The thin films contained 2, 4, 6 or 8 wt% AB. Electrical measurements showed that the s…
A review of the requirements for collecting X-ray diffraction data from protein crystals is given, with an emphasis on the properties of the crystal and its diffraction pattern. The size, unit-cell dimensions and perfection of the crystals can all be related to the required size and divergence of the incident X-ray be…
During the fall and winter of 1995, ninety-two samples were collected from twenty-three sampling stations in the Matanza-Riachuelo river basin. Epipelic diatoms and physico-chemical parameters were studied to establish water quality. Ecological methodologies (species richness, diversity and saprobity indices and multi…
Determination of the density of protein crystals by flotation in organic solvent density gradients using simple methods for the preparation of the density gradients and the transfer of crystals into these gradients is described. The method was tested with crystals of hen egg white lysozyme. These methods are especiall…
The Lang X–ray topography method and double–crystal plane–wave X–ray topography combined with image treatment have been used to study the zonal inhomogeneity formation during crystal growth from solutions. It is shown that striation formation in crystals can be caused not only by the variations of the external growth…
Porous, oxygen‐ion‐conducting ceramic membranes can have applications as supports for fuel cells, sensors, and thin membrane films, or as filters for membrane filtration. This paper reports on the preparation of unsupported and supported yttria‐stabilized zirconia (YSZ) and yttria‐doped bismuth oxide (BY) membranes wi…
Nanocrystalline materials have a proportion of atoms at grain boundaries that can be as high as 50% and are thus expected to have properties quite different from those of bulk or large-grained polycrystalline materials. In this article, we study the influence of the presence of grain boundaries on thermal expansion, m…
A summary of detailed measurements of the field and temperature dependence of the ac susceptibility, magnetization and the longitudinal and transverse magnetoresistivities of ceramic La 0.67 Pb 0.33 MnO 3 is presented. Detailed analysis of the magnetic data provides an estimate of 340.5±0.5 K for the paramagnetic to f…
Eprosartan mesylate (SKF 108566-J; EM) is an antihypertensive agent approved for marketing in the USA. EM dihydrate was prepared by three methods, one of which included suspending the anhydrous drug in an aqueous solution of 1.0 M methanesulfonic acid to form a slurry, followed by filtration. The dehydration kinetics…
Abstract This study investigates the complexes formed between amino acids, which are the natural degradation products of organic matter, and smectites. Thus, the adsorption and desorption behavior of cysteine and Na-, Ca-, Cu-homoionic smectites with different layer-charge location, a montmorillonite, and a beidellite…
Salene–FeIII complexes of the types LFeCl and [LFe(CN)2]− were treated with organometallic reagents to introduce the cyanide-linked units (CO)5Cr, (CO)5Mo, (CO)5W, Cp(CO)2Fe, Cp(dppe)Fe, and Cp(PPh3)2Ru. IR spectra and structure determinations revealed that all resulting complexes contained M–CN units with N coordinat…