Materials Literature
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From molecular-dynamics simulations, it is demonstrated that the structure factor has a second-peak splitting feature not only for glass states but also for supercooled-liquid states in some metallic cases. This appears to be due primarily to the presence of icosahedronlike clusters in these cases. This suggests that…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLiquid crystalline polyethers based on conformational isomerism. 20. Nematic-nematic transition in polyethers and copolyethers based on 1-(4-hydroxyphenyl)2-(2-R-4-hydroxyphenyl)ethane with R = fluoro, chloro and methyl and flexible spacers containing an odd number of methyl…
During typical composites manufacturing processes, fibers are deformed in ways that alter their processing characteristics (e.g., permeability, stresses and resin pressure, etc.) and their resulting microstructure (fiber volume fraction, void fraction, etc.). In this paper, we review all available data for the deforma…
Three cobalt–copper hydroxysalts with chemical formulae Co(CO3)0.5(OH)1.0· 0.11H2O, Co0.67Cu0.33(CO3)0.4(OH)1.2 and Co0.49Cu0.51(CO3)0.43(OH)1.14 have been obtained and characterised by powder X-ray diffraction (XRD), thermal analysis (TG, DTG and DTA), diffuse reflectance spectroscopy (DRS), magnetic susceptibility a…
We investigate the effects of shear flow on the smectic phase of thermotropic and lyotropic liquid crystals. We show that shear flow transforms a smectic-A thermotropic liquid crystal into an orthorhombic solid by the suppression of undulation fluctuations. In contrast, the lyotropic ${\mathit{L}}_{\mathrm{\ensuremath…
Contact-angle measurements in air and water environments and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface properties of air-corona-treated polypropylene (PP) and poly(ethylene terephthalate) (PET) films. Surface properties were examined as a function of the storage time at various tempe…
Abstract Tempestites exhibit a characteristic suite of trace fossils that are related to the population strategies of benthic organisms. The general succession consists of: (a) a fairweather resident trace fossil suite; (b) a sharp basal contact, with or without a basal lag; (c) parallel to subparallel laminations (re…
Corrections for stress‐wave dispersion in a 76.2‐mm‐diameter split Hopkinson pressure bar (SHPB) system have produced more accurate data in the regime between yield point (elastic limit) and maximum stress of dynamic stress‐strain curves of concrete, so that the rate dependence of the stress on the inelastic strain ra…
Two potential parameter sets for alkali silicates were derived on the basis of ab-initio MO calculations. One is a model containing completely ionic alkali (model I), and another is that derived from cluster calculations (model II). These sets were tested against the crystal, glass, and liquid of metasilicates. The mo…
An electron-irradiation-induced crystalline-to-amorphous (C-A) transition in β-SiC single crystals has been studied as a function of irradiation temperature by means of ultra-high-voltage electron microscopy. The C-A transition can be induced at temperatures below 340 K. The dose of electrons required for the C-A tran…
An axial field permanent-magnet brushless DC motor that utilizes tape wound amorphous iron and an air gap winding is proposed. Simplified waveforms and performance equations for this type of machine are presented. The machine equations and waveforms are verified with a proof-of-concept machine. No-load iron losses are…
Schlieren texture has been observed in Sc and SCA liquid-crystalline phases. We found that defects of strength s=± 1/2 exist in the SCA phase in addition to those of s=± 1 observed in the Sc phase. The existence of the s=± 1/2 wedge disclination is explained by taking account of a screw dislocation. This complex defec…
Summary— The cellulose‐protein fibrils, which constitute by far the bulk of the fibrous fraction of the sea peach tunic ( Halocynthia papillosa ), were structurally and chemically characterized, either in situ or after extraction procedures, with the use of classical electron microscoy combined with diffraction contra…
In this paper we present results obtained on the preparation of amorphous silicas from aqueous solutions of the octahedral silicon complex K2[Si(C6H4O2)3]· 2H2O at approximately neutral pH conditions (initial pHs of 6.67 and 7.1) in the presence and absence of cellulose. 1H solution NMR was used to monitor complex con…
Polymers from 1,4:3,6-Dianhydrosorbitol 1,4:3,6-Dianhydrosorbitol and several similar dioles are easily accessible by technical processes. They can be used for the the synthesis of high molecular polyesters, polyurethanes and polycarbonates. The thermal and mechanical properties of the obtained polymers are similar to…
Abstract SERS spectra of cytosine, 1‐methylcytosine, 5‐methylcytosine and 1,5‐dimethylcytosine on silver and on copper colloids are reported. A study of the influence of pH on the normal Raman spectra of these compounds was made in order to understand better the behaviour of these molecules on metal surfaces. The resu…
A hysteresis controller with a sinusoidal band for current regulation is described. The behavior of the conventional fixed-band controller and the proposed sinusoidal band controller has been thoroughly studied. Simulation results demonstrate that with no lockout (permitting a very high switching frequency) the curren…
New viologens, in which two pyridinium moieties are linked by a central five-membered heteroaromatic or phenylene framework, giving stable radical cations on single electron reduction and showing an intense fluorescence emission are efficiently synthesized and characterized.
The mechanical behavior and the effect of deformation on the martensitic transformation of Ti44Ni47Nb9 alloy were investigated in detail by tensile tests and electrical resistance measurements. The tensile behavior at various temperatures, the effect of annealing temperature after cold work and the aging effect were s…
A free boundary value problem is considered modeling solidification of a liquid by making use of the phase field approach as it was introduced by G. Caginalp [1] and others. Existence and uniqueness is proved as well as stability under mild assumptions. But the main goal of this paper is to establish results for the d…