Materials Literature
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The first observation of the low lying B 2(LO), B 2-polariton, E(LO), and E(TO) modes in the paraelectric phase of KDP have been attained by the z(xy)z, z(xy)z+Δy, x(yz)zx, and z(xz)x Raman scattering spectra, respectively. The spectra of both B 2-modes have been explained by a single damped harmonic oscillator model.…
The reaction of alkaline solutions of Na2[WO4](ca. 10–3 mol dm–3) with acid has been studied by stopped-flow-spectrophotometric and indicator-spectrophotometric techniques. The formation of ‘acid paratungstate’, [H8W6O24]4–, has been detected. It is the most important of the transient intermediates formed ca. 500 ms a…
The heavier p block metal ions in their two oxidation states (upper state corresponding to the group number and the lower state two units less with the outer s2 electronic configuration) give rise to intense absorption in the ultraviolet region. Absorption by the upper state arises through an electron transfer mechani…
The complex cis-Fe(phen)2(NCBPh3)2(phen = 1,10-phenanthroline) exhibits synchronous spin- and stereo-isomerization in CH2Cl2, suggesting a previously unrecognized mechanism for spin-equilibria in octahedral complexes.
The influence of magnetic fields on ferroelectric phase transition parameters is considered in the framework of the vibronic microtheory and is shown to be essential larger than for ferroelectric semiconductors investigated earlier. Numerical estimates are given for doped SrTiO3.
Biurea decomposes in the temperature range 230–260° to yield gas, a white sublimate, and a viscous liquid residue. The gas is mainly ammonia (ca. 71%), but some carbon dioxide (ca. 17%) and nitrogen (ca. 12%) are also present. The main constituent of the sublimate is urea and that of the residue urazole. The products…
In the structure of [La(NO3)3(H2O)5]·H2O (determined by X-ray crystallography) the lanthanum atom is surrounded by three bidentate nitrate ligands and five water molecules; this result indicates a hitherto unknown co-ordination number of eleven for a trivalent lanthanoid.
The electrical transport properties of splat-cooled amorphous semiconductors In20Te80, Ga20Te80, and Ge15Te85 were investigated by measuring the thermoelectric power S and dc resistivity ρ between 140 and 300 °K. For as-quenched samples, both S and logρ show linear relationships with 1/T, indicating a p-type intrinsic…
Atmospheric pollution can be a serious problem for the insulators of outdoor e.h.v. substations, especially when situated near the coast, as it can lead to flashovers due to wet salt deposited as a result of storms. A method of maintaining such insulators in a condition to provide the required degree of security is th…
The structure of molten Na2WO4 has been investigated by the radial distribution function based on X-ray scattered intensity data collected at ≈ 760°C and has been analysed by the correlation method. WO4 tetrahedra existing in the crystalline state are shown to be preserved in the molten state. Various arrangements of…
Le système Cu/H3PO4 présente un comportement rythmique en liaison avec la zone d’instabilité située au début du palier de polissage. Le phénomène existe dans les conditions usuelles du polissage électrolytique du cuivre mais également lorsque certaines conditions expérimentales sont modifiées (concentrations, températ…
Polymethylene sulfides and related compounds possessing interesting properties are obtained when the highly reactive intermediate (2) (diradical or zwitterion?) arising from tetrameric thioformaldehyde (1) and boron trifluoride-diethyl ether is allowed to act upon trimeric thioformaldehyde, or substituted oligomeric t…
Sintering of alumina has been carried out in presence of two eutectic glass compositions, viz. CAS (1): CaO–23.0, Al2O3–15.0, SiO2–62.0 and CAS (2): CaO–52.0, Al2O3–41.5, SiO2–6.5. 10, 15, 20 and 25 per cent by weight glass were used with different particle sizes of Al2O3 and sintered at 1400° and 1460°C. Effect of pa…
Abstract Three-terminal dielectric bridge measurements (in the range 20 Hz to 100 kHz between — 5 ° C and —90 to — 120 ° C) have been made of ice doped with (a) conductivity-enhancing ionic impurities (HCl, HF, NaCl, KF, NH 4 F) and (b) conductivity-depressing solutes (NH 4 OH, NH 4 Cl, NH 5 CO 3 , NaHCO 3 ). Blocking…
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Abstract Recent trends in fabric composition, choice of raw materials, and government regulations are placing new demands on the use and utility of antiredeposition additives.
The reversible thermal reaction of the photoisomer of 6,7,14,15-tetrahydro-15,16[1′,2′]8,13[1″,2″]-dibenzenodibenzo [a,g]cyclododencene(bi[anthracene-9,10-dimethylene]) in the solid state has been investigated. The reaction mechanism was studied using differential thermal analysis and optical spectroscopy and was foun…
Abstract Dipole moments and their temperature dependence have been measured in p ‐dioxane for fractionated novolac phenol–, o ‐cresol–, and p ‐cresol–formaldehyde polymers. The phenol–formaldehyde fractions covered a molecular weight range of 200 to 6100, and the limiting dipole moment ratio 〈μ 2 〉/ xm 2 is 1.48. The…
The diffusivity and solubility of hydrogen in both annealed and cold worked polycrystalline nickel were determined in the temperature range of 10 to 60°C by means of an electro-chemical permeation technique. The following results are obtained. The diffusivity increases slightly with increase in grain size, whereas the…
This study was an attempt to discover whether a deficiency in hepatic oxaloacetate can explain the acceleration of ketogenesis observed after the ingestion of medium-chain triglycerides (MCT, constituent fatty acids from C8 to C12). The method of investigation used consisted in supplying oxaloacetate (by intraperitone…