Materials Literature
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Abstract The longitudinal penetration of micromolecular liquid solvents (acetone, dioxane) or swelling agents (methylene chloride, methanol) into unoriented (unstretched) cellulose acetate film has been studied in detail by a variety of techniques, including observation of visible penetrant fronts, birefringence profi…
The aim of the present work was to identify the structural characteristics of calcium chromium oxide formed at molar ratios CaO/Cr 2 O 3 ≥ 3/1 and at elevated temperatures by the use of nondestructive techniques: instrumental neutron activation analysis (for determination of the total chromium content), electron param…
Low‐thermal‐expansion ceramics having arbitrary thermal expansion coefficients were synthesized from homogeneous solid solutions in the system KZr 2 (PO 4 ) 3 ─KTi 2 (PO 4 ) 3 (KZP–KTP). Dense and strong ceramics were fabricated by sintering at 1100° to 1200°C with 2 wt% MgO. The thermal expansion coefficient increase…
The chemical and mineralogical composition of the clay fractions of two Paleudults from Central Kalimantan, Indonesia have been investigated. The dominant phyllosilicate in both profiles is poorly crystalline kaolinite. Both profiles contain small amounts of an irregular interstratified hydroxy-interlayered illitic ve…
Processing of cellular polyurethane was investigated experimentally and theoretically to examine the possibility of ultrasonic foaming. Polyol resin was supersaturated with nitrogen and ultrasonic excitation was applied for copious bubble nucleation. The ultrasonic excitation resulted in good foam structure whose size…
Thermal oxidation of blends of polystyrene and poly(vinyl methyl ether) containing a hindered phenol as antioxidant was studied at 110°C. The incorporation of the antioxidant in the miscible blend lengthens the induction period and lowers the rate of oxidation. Phase separation which preceded the end of the induction…
Lead titanate and lead magnesium niobate ceramics are fabricated from powders prepared by hydrothermal synthesis. The results of powder and ceramic characterisation are presented and compared with similar data obtained for ceramics fabrication by conventional mixed oxides.
Well-separated magnetic particles (∼1 μm size) of Nd2Fe14B alloy are successfully crystallized using an oxygen-reduction-diffusion process. In this process suitable mixtures of Nd2O3, Fe, and B precursor powders were sintered (at 900–1000 °C for 1–3 h) with finely dispersed calcium granules (reducing agent) and anhydr…
Abstract An experimental procedure has been developed to assess the various components of the mixing energy when preparing carbon black filled rubber compounds. A microprocessor based instrument developed for laboratory mixers allows the measurement and recording of all the relevant parameters of the operation, which…
Abstract X‐ray photoelectron spectra of the valence band and X‐ray‐excited O KLL Auger transition of pumice‐supported Pd and Pt catalysts have been obtained and compared to the corresponding spectra of pumice (a naturally occurring amorphous aluminosilicate). The changes observed indicate interaction between metal and…
Abstract Poly(thio-2,6-dimethyl-1,4-phenylene) has been prepared by the oxidative polymerization of bis(3,5-dimethylphenyl) disulfide. The obtained polymer is amorphous and soluble in common organic solvents. The properties of the polymer are similar to those of poly(oxy-2,6-dimethyl-1,4-phenylene), rather than poly(t…
We have developed an innovation of the polarized reflectances measurement technique for thickness and index (PRETTI) method, PRETTI-S, which is a simple and accurate technique to obtain the refractive index n and thickness d of a thin film by using S-polarized and P-polarized reflectances measured at oblique angles of…
This paper provides the specifications of a refractory lining for alumina electrolytic cells capable of ensuring good resistance to corrosion by the cell chemicals, while maintaining desirable thermal characteristics during service. Several refractory materials were tested in the Alcan's standard electrolysis bath tes…
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…