Materials Literature
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The synthesis of the two monomers M 1 and M 2 and a series of new side-chain cholesteric liquid crystalline elastomers P 2 − P 8 is presented. The chemical structures of the monomers and elastomers obtained were confirmed by FTIR or 1 H NMR spectroscopy. The cross-link density of the elastomers was determined by swell…
ABSTRACT The effect of addition of CaCl2 2H2O and MgCl2 6H2O on crystallization kinetics and the rheological behavior of a 70% trehalose solution was studied by polarized light microscopy and dynamic oscillatory rheometry. Salts caused a delay on nucleation with induction times for crystallization longer for Mg2+ than…
In order to delay the undesirable discoloration of poly(vinyl chloride) (PVC) by heating, the synergetic effect of poly(vinyl alcohol) (PVA) as co-stabilizer with a mixture of zinc and calcium stearates was clarified. Usually, the abrupt discoloration was caused by the formation of a π-complex between the cool colour-…
Abstract Isothermal crystallization of natural rubber (NR) dispersed in styrene-butadiene rubber (SBR) was made at −25 °C to investigate effects of both gel fraction of the rubber and morphology of the blend on the crystallization. NR, thus used, was lightly crosslinked model compound (model-NR), which was cured with…
Single-walled carbon nanotubes (SWCNTs) are synthesized by the ablation of a catalyst-containing carbon target with a cw CO 2 laser. Emphasis is on ablation conditions that are favorable to self-organized SWCNT synthesis. It is shown that the graphite target intensely evaporates with the formation of fractal-like tube…
Porous silicon (por-Si) is prepared by the electrochemical etching of single-crystal n -silicon in an aqueous-alcoholic solution of hydrofluoric acid in the presence of hydrogen peroxide oxidizer. The dependence of the high-frequency C-V characteristics of Al/por-Si/Si heterostructures on the relative humidity is stud…
Negative charging of a specimen may produce the image contrast of yielding the information under the insulating thin film in scanning electron microscopy. To clarify and make good use of the recently developed negative-charging contrast (NCC), we propose a simplified procedure for quantifying secondary electron (SE) i…
This paper discusses the implications of X‐ray photoelectron spectroscopy (XPS) and scanning Auger microscopy (SAM) results that revealed the presence of sizable amounts of carbon‐bearing species at the joint of a Roman lead pipe (fistula) and at the surface of a Roman bronze statue. The detailed description in Pliny'…
Abstract Segmental relaxation in a series of polymethylphenylsiloxanes (PMPS) was studied using dielectric spectroscopy. The measurements covered a temperature range of more than 40 deg at pressures from ambient to 115 MPa. The results confirmed that the shape of the loss peak is independent of temperature, pressure a…
We have studied cell gap-dependent driving voltage characteristics in a homogeneously aligned nematic liquid crystal (LC) cell driven by a fringe electric field, termed the fringe field switching (FFS) mode. The results show that for the FFS mode using a LC with positive dielectric anisotropy, the operating voltage de…
Twenty impact diamond samples from the Popigai, Ries, and Lappajärvi astroblemes were analysed using cathodoluminescence (CL) at room temperature (RT). Five of the samples were further investigated at liquid nitrogen temperature (LNT). Cathodoluminescence images allowed for the discrimination of diamond from graphite,…
Abstract The effect of Mg 2+ ions on the gel formation in fresh and commercial high ammonia natural rubber latices (FL-latex and commercial HA-latex) was analyzed from the gel content and 2+ content after treatment with (NH 4 ) 2 SO 4 . The gel content of rubber from commercial HA-latex decreased significantly after (…
Abstract Although bifunctional organosilanes, particularly bis-(triethoxy-silyl-propyl) tetrasulfide (TESPT), are very efficient silica-rubber coupling agents, a high level is required to realize an optimum balance of processing as well as other performance characteristics. As to the functionality of TESPT in silica s…
Kinetic modeling of the catalytic oxidation of trichloroethylene (TCE) over a palladium supported on alumina was evaluated. On the basis of previous studies on the effect of temperature, inlet TCE and oxygen concentrations, and the space velocity on the reaction rate, a five-step reaction network scheme, based on an E…
35 Cl NMR spectra were measured using the highest-temperature solid phase of n-C x H (2x+1) NH 3 Cl and n-C x H (2x+1) ND 3 Cl (x=5−10). The observed quadrupole coupling constants (e 2 Qqh −1 ) decreased upon heating in this phase, and significant frequency differences of ca. 20 − 30 kHz were detected between the -NH…
Plastic strain localization in single crystals of pure metals and alloys is studied on the yield plateau and at the easy glide stage with a zero or small strain hardening coefficient. The difference between localization patterns in the two cases is explained, and strain localization mechanisms are suggested. At these…
A simplified three-dimensional structural model for a series of nonwoven fabrics is presented. The corresponding directional permeabilities of the fabrics are calculated based on the measured two-dimensional fiber orientation distribution. The influences of fiber diameter, fabric porosity, and fiber orientation distri…
The present work studies the effect of niobium addition on the mechanical properties and microstructure of an as-cast 4·3%Ni alloyed ductile iron. The experimental iron was made from high purity raw materials in a laboratory induction furnace. Eight castings were produced with niobium content in the range 0–0·8%. Sili…
Samples of double rare-earth ferrite La1 xNdxFeO3 are synthesized by a high-temperature double sintering ceramic technique. X-ray diraction shows that all compounds have an orthorhombic structure. The values of lattice parameter and the volume of the unit cell, changes with increasing Nd 3+ content. The Goldschmidt to…
ABSTRACT Films for potential food use were prepared from aqueous solutions of β‐glucan extracted from hulled barley, hull‐less barley, and oats. The extracts (75.2–79.3% β‐glucan) also contained proteins, fat, and ash. Glycerol was used as a plasticizer. The films were translucent, smooth, and homogeneous in structure…