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We have used for the first time the electron-microscopy technique to reveal the pure ferroelastic phase domain structure of lead phosphate, Pb3(PO4)2. The domain configuration confirms previous identifications of the symmetry elements lost at the transition. The domains are found separated by thin walls whose thicknes…
Irradiation of 3-alkylcylcopentenones in potassium dodecanoate micelles leads to greatly increased efficiency of dimerisation over that in homogeneous solution and regiospecific head-to-head control far beyond that possible by solvent variation.
An homologous series of mesomorphic compounds, the I-(4-alkoxy or alkyl-benzoyloxyphényl)-2-(4′-pentylphenyl)-ethanes, has been synthesized. The compounds with R = alkyl have low-melting points and wide mesomorphic ranges, for example from 33.5°C to 106.5C. The compounds with R = alkoxy exhibit a smectic polymorphism;…
Abstract The compounds CaAgP and CaAgAs have been prepared and their structures have been determined. They are isotypic and crystallize in a modified Fe 2 P-structure (space group P6̄2m-D 3 3h ) with the lattice constants: CaAgP a = 704,5(1) pm, c = 417,4(1) pm, CaAgAs a = 720,4(1) pm, c = 427,0(1) pm.
The surface composition of swarfs from leaded Cu-40Zn has been determined by Auger electron spectroscopy and ion etching as a function of bulk-lead content and machining conditions. The lead additive is distributed at the swart surface as a continuous thinfilm of monatomic thickness and as varying proportions of thick…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTProton exchange and temperature studies of pyrazole in dimethyl-d6 sulfoxide by carbon-13 NMRWilliam M. LitchmanCite this: J. Am. Chem. Soc. 1979, 101, 3, 545–547Publication Date (Print):January 1, 1979Publication History Published online1 May 2002Published inissue 1 January…
Abstract— High temperature cyclic deformation in nickel is investigated by comparing its cyclic hardening curves at constant strain amplitudes at four temperatures with the monotonic hardening curves and by detailed electron microscopic examination of the bulk. Just as at ambient temperature, there are broad similarit…
The refractive indices and densities of a number of 4,4'-disubstituted phenyl benzoates and the Merck nematic phases ZLI 1052 and ZLI 389 are reported as functions of temperature in the nematic and isotropic phases. Also two isomers of 4,4'-disubstituted phenyl thiobenzoates are investigated. Comparison of Vuks model…
The authors have studied experimentally on the coprecipitation of dissolved silica with calcium carbonate (calcite or aragonite) and on the influence of silica dissolved in a parent calcium bicarbonate solution on the crystal form of calcium carbonate precipitated from the parent solution. The coprecipitation of disso…
The rates at which molecular sequences may deposit onto growing lamellae in a crystallising polyethylene melt are examined on the basis of the results of recent self-diffusion experiments in such melts, in conjunction with theories of molecular dynamics in polymer melts based on the reptation picture. The results are…
INCONEL Alloy 690 (Ni-30Cr-9Fe-0.02C, wt. %), is a new high-chromium nickel-base alloy, designed to provide a stable austenitic structure combined with resistance to corrosion and oxidation in aggressive industrial environments at elevated temperatures. Extensive laboratory evaluation of Alloy 690 during the past 12 y…
Abstract The generation of blisters due to irradiation by helium ions is investigated theoretically. The possible pressure in helium bubbles in metals, the binding energy of helium atoms and vacancies to a bubble are calculated. The kinetics of bubble growth is studied. Using the known profiles of implanted ions and d…
The formulae currently used to calculate volume changes on activation, ΔV≠0 and reaction, ΔV≠0, are shown to be unsuitable even at pressures of ≈ 1 kbar, and calculations are shown to be sensitive to errors, owing to empirical coefficients present in the formulae.The ΔVp=ΔV0[1–α ln (1 +βp)] relationship is substantiat…
The solubilities of octacosane in decane and dodecane and of hexatriacontane in hexane, octane, decane and dodecane in the temperature interval 11–38°C have been determined, and the standard enthalpies and entropies of solution, ΔHd and ΔSd, have been calculated from the solubility curves. For hexatriacontane ΔHd incr…
Using the optical Zeeman absorption spectrum of ${\mathrm{Er}}^{3+}$ and ${\mathrm{Cr}}^{3+}$ in ErCr${\mathrm{O}}_{3}$, the field-induced spin reorientations between ${\ensuremath{\Gamma}}_{1}$, ${\ensuremath{\Gamma}}_{2}$, and ${\ensuremath{\Gamma}}_{4}$ phases are investigated extensively. The data are analyzed usi…
The nematic liquid crystal is considered as a weak electrolyte. The analysis of the time behaviour of the transient current flowing through the sample allows the estimation of the mean mobility of anions and cations. The electrohydrodynamic flows are avoided thanks to the application of low voltages. For p-octyloxyphe…
Exposure of methanolic or acidic aqueous glasses containing halide salts together with organic phosphines or sulphides gave the electron loss centres R3P˙+ or R2S˙+ which reacted with halide ions (hal–) to give the σ* radicals R3P·—hal and R2S·—hal which were identified by e.s.r. spectroscopy. These were formed in com…
The present authors have studied the influence of barium and magnesium ions, which are contained together in a calcium bicarbonate parent solution, on the crystal form of carbonate formed from the parent solution. Magnesium ions in a parent solution inhibit calcite formation and favor aragonite formation, whereas bari…
Liǵuid us and subsolidus phase relations were studied using the quenching technique. The system contains four ternary compounds stable to liquidus temperatures: Na 2 TiSi 4 O 11 , Na 2 TiSi 2 O 7 , Na 2 TiSiO 5 , and Na 2 Ti 2 Si 2 O 9 . Six eutectics, eight peritecties, and eight thermal maxima were located and a reg…
The influence of metallurgical variables on the environment-sensitive cracking of austenitic Fe—er—Ni alloys, in particular austenitic stainless steels, has been examined. It has been demonstrated that the cracking susceptibility is sensitive to such metallurgical variables as composition, grain size, microstructure,…