Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh molecular weight aromatic polyamides from aromatic diiodides and diaminesS. Richard Turner, Robert J. Perry, and Richard W. BlevinsCite this: Macromolecules 1992, 25, 18, 4819–4820Publication Date (Print):August 1, 1992Publication History Published online1 May 2002Publi…
Three novel alicylic crown ether liquid crystals were synthesized, of which two were chiral. Preliminary studies on their mesomorphic properties were carried out.
Two first-order analytic solutions and a second-order analytic solution for the case of lossless-dielectric unslanted volume transmission gratings are compared for the case of weak grating index modulation and significantly off-Bragg replay. It is shown that the analytic solution predicted using the Beta-value method,…
Abstract The thermo‐oxidative stability of high‐density polyethylene (HDPE) prepared by silica supported Ziegler‐Natta, bis(triphenylsilyl)chromate and bis(cyclopentadienyl)‐chromium(II) catalyst systems was examined by chemiluminescence (CL) techniques and thermogravimetric (TG) analysis. In particular, the technique…
Abstract Silicic acid (SA) was extracted with THF from aqueous sodium metasilicate (SMS) solutions neutralized with hydrochloric acid, followed by silylation to give silylated SA from which the condensation and structure of SA in tetrahydrofuran (THF) were investigated. The degree of extraction markedly depends on SA…
Abstract The two indolocarbazoles 2 and 4 were synthesized via the reductive ring closure of dinitrodiphenylbenzenes with triethylphosphite as reducing agent in a high boiling solvent. The electrochemical behaviour of the title systems is discussed.
The inverse-scattering problem for a scalar wave field incident at grazing angles upon a one-dimensional moderately rough surface is considered. The problem is solved directly by treating the scattering integral as an integral equation in the unknown field derivative at the surface and coupling this to a simple equati…
Ultrasonic, piezoelectric and thermal expansivity measurements have been carried out using single-crystal samples of 3-nitroaniline (meta-nitroaniline mNA). Longitudinal and transverse velocity measurements in six crystal directions were used to determine the nine elastic coefficients. These data are discussed in rela…
Abstract The study of thio compounds as inhibitors against the corrosion of a carbon steel (XC 38) in contact with 3% sodium chloride using a rotating disk electrode was performed. Stationary and transient measurements were carried out. Inhibition efficiency was estimated from both current‐potential characteristics an…
A new biphenyl alkyloxy benzoate series is synthesized. Thermodynamic, structural and dielectric measurements have been performed on the two homologous n=8 and n=10. For these two compounds, the sequences N*-SC* or N*-SA-SC* are respectively observed under atmospheric pressure. Pressure-Temperature phase diagrams show…
Ferroelectric properties for the copolymers of acrylonitrile and allylcyanide were investigated in a temperature range of 20°C to 180°C. The copolymers containing a certain fraction (35 mol%) of allylcyanide showed a dielectric anomaly with the peak due to the structural change of paracrystal around 120°C, which is ab…
Abstract Es wird ein neuer Nickel‐Chrom‐Molybdän‐Werkstoff, Nicrofer 5923 hMo, Leigierung 59 (Werkstoff‐Nr. 2.4605) vorgestellt, der für härteste Korrosionsbeanspruchungen entwickelt wurde, wie sie in der Chemischen Industrie und in heutigen Umweltschutzsystemen auftreten. Diese Legierung, die im wesentlichen aus 59%…
Abstract The existing models of the foaming process in reaction injection molding are inadequate for predicting the bubble‐size distribution, which influences many properties of interest. This work attempts to develop a model for the bubble‐size distribution under conditions of free rise. The population balance equati…
A study has been done of the effect of neutral salts (NaCl and CaCl2) on the mechanism of type I collagen triple helix folding and unfolding in concentrated acetic acid solutions (2-8.8 M). It is shown that in these conditions, thermoabsorption and secondary structure change in heated solutions proceed in two consecut…
Abstract Brittle failure, a significant design issue for plastic components subject to impact loads, is especially catastrophic when the material is normally ductile. Such behavior is not adequately understood relative to the micromechanisms, controlling parameters, and design consequences in plastics. Previous work h…
Galvanic corrosion between dissimilar materials was investigated using laboratory simulations of oil/gas production environments. Galvanic corrosion of materials used in production equipment (4130, 9 Cr, 13 Cr, 2205, 718, 825, NIC 32, NIC 42, SM 2550, Beta-C Ti, C-276, 925) was studied in corrosive environments, which…
The study examines the effect which the composition of hot‐pressed electroconductive ceramics has on their structure, mechanical properties, and oxidation behavior, for ceramics of the type AIN–Al 2 O 3 –42 wt% TiN, differing in the AIN/Al 2 O 3 ratio. The results are physico‐mechanical property data, including densit…
A series of cellobiose octaalkanoates, Cel-II-n (n is the carbon number of the alkyl chain), with n = 7–14 were prepared and their mesogenic properties examined by differential scanning calorimetry, optical polarizing microscopy and X-ray diffraction. All of these compounds form enantiotropic discotic columnar phases,…
Having generated and identified a carbon thirteen NMR signal arising exclusively from PC chains the PC/PS interface, we can now perform NMR relaxation experiments to characterize the microscopic dynamics of these chains. A difference pulse sequence is used which includes a period for carbon dephasing under the influen…
Abstract In the copper deposit of Salobo 3A (Brazil), nontronite-like clay samples were found at the bottom of the weathering blanket. Samples were fractionated first by sedimentation and then by a HGMS method. From XRD data, it was found that the samples are essentially smectite with kaolinite in very small quantitie…