Synthesis and characterization of the tetra-aminotriafulvalene dication
The tetra-aminotriafulvalene dication (3), the first dication of the simplest fulvalene, has been synthesized and its spectroscopic characteristics are briefly described.
Materials Literature
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Structure and catalytic activity of CoχMg1–χAl2O4 spinel solid solutions. Part 1.—Cation distribution of Co2+ ions
The cation distribution in CoAl2O4 and in several CoχMg1–χAl2O4 solid solutions with χ ranging from 0.05 to 0.5 has been studied by magnetic susceptibility, reflectance spectroscopy, lattice parameter variation and analysis of some X-ray reflections whose intensities are particularly sensitive to variation in cation p…
Accelerated voltage endurance testing of micaceous insulation systems for large turbogenerators under combined stresses
The electrical life of micaceous insulation for high-voltage electrical machines was investigated by means of accelerated voltage endurance tests under carefully controlled operating conditions. The aging mechanism is assumed unchanged when the insulation is subjected to dielectric field strengths up to ten times norm…
Magnetic study of the terbium iron garnet, Tbig, along the easy (111) direction : molecular field parameters
Magnetization and susceptibility measurements, over the range 4.2-295 K have been made on single crystal TbIG along the (111) direction. The paramagnetic Curie point and the Curie constant are markedly different from the values established by Pauthenet in polycrystalline samples. The effects of the crystalline field a…
The role of intercrystalline links in the environmental stress cracking of high density polyethylene
Abstract Results of dynamic mechanical spectroscopy, infrared spectroscopy, and tensile stress‐strain data show that the non‐ionic surfactant Igepal CO‐630, often used as a stress cracking agent, and water are absorbed by high density polyethylene to cause an internal stress relaxation of the intercrystalline tie mole…
A Quantitative Analysis on the Initiation of Crevice Corrosion of Stainless Steels
A quantitative analysis has been made on the initiation of crevice corrosion on the following assumption: (1) The pH in crevice is uniquely determined by the total charge passed as passive current, and (2) the crevice pH decreases to depassivation pH at which active dissolution, crevice corrosion, initiates.The obtain…
A group–dipole interaction model of the molecular polarizability and the molecular first and second hyperpolarizabilities
The group–dipole interaction model is generalized to treat the molecular polarizability and the molecular first and second hyperpolarizabilities. A molecule is divided in groups; each group is characterized by a polarizability and by first and second hyperpolarizabilities, and it resides in an internal molecular elect…
Interaction of lanthanide shift reagents with co-ordination complexes; direct observation of nuclear magnetic resonance signals for free and complexed tris(pentane-2,4-dionato)cobalt(III) at ambient temperature, and X-ray crystal and molecular structure of the 1 : 1 adduct formed
The changes in the 1H n.m.r. spectrum of tris(pentane-2,4-dionato)cobalt(III) in CDCl3 on incremental addition of tris(1,1,1,2,2,3,3,-heptafluoro-7,7-[2H6]dimethyl[2H3]octane-4,6-dionato)europium {Eu([2H9]fod)3} have been determined at 32°C; 1 : 1 adduct formation occurs, chemical exchange with respect to the n.m.r. t…
Effect of Relative Humidity on the Wettability of Steel Surfaces
Metals and metal oxides are usually classed as high-energy solids since in the ultra-clean state they have surface free energies typically greater than 500mJ/m2. However, Bernett and Zisman1 measured the critical surface tension, yc , of wetting of various hydrophilic, high-energy, metal oxides and pure metals at two…
Polyurethane Elastomers in Surgery
Review of polyurethane elastomers and several applications as surgical implants.
Sodium borohydride and amine-boranes, commercially important reducing agents
Conference International Meeting on Boron Chemistry, International Symposium on Boron Chemistry, IMEB, Boron Chemistry, Third, Munich & Ettal, Federal Republic of Germany, 1976-07-05–1976-07-09 Published Online: 2009-01-01 Published in Print: 1977-01-01 © 2013 Walter de Gruyter GmbH, Berlin/Boston
Low-frequency dielectric dispersion in tri-glycine sulphate
Measurements are reported of the complex dielectric permittivity, ε(ω), of single crystal tri-glycine sulphate (TGS) at temperatures on either side of the ferroelectric Curie temperature, Tc, covering the frequency range ω/2π = 10-105 Hz. By contrast with the reported strong dispersion in the GHz region, the dielectri…
Analytical method of calculating the electromagnetic field and power losses in ferromagnetic halfspace, taking into account saturation and hysteresis
The steady-state solution of electromagnetic-field problems in ferromagnetic materials is given. The effects of magnetic saturation and hysteresis are included. The solution is based on the differential diffusion equation assuming variable complex magnetic permeability. A precise formula is given to calculate the tota…
Photoluminescence and Optical Properties of Ge1-xSexGlasses
The photoluminescence spectra in Ge 1- x Se x glasses with a composition of 0.5≤ x ≤0.9 along with the optical absorption spectra have been measured. The position of the emission peak is almost independent of the Se composition. The emission intensity, however, is most intense for the composition Ge–Se 2 , indicating…
Chemical implantation of 10-keV H+ and D+ in rutile
Rutile (TiO2) implanted with 10-keV H+ and D+ exhibits broad ir absorption bands at 3400 and 2505 cm−1, respectively. The D+ implantation also induces a sharp band at 2438 cm−1. This 2438-cm−1 band corresponds to the sharp hydroxyl absorption peak at 3277 cm−1 typically present in flame-grown rutile crystals. In addit…
Single-crystal vibrational spectra of tetragonal and orthorhombic lead monoxide
All the fundamental modes of vibration of tetragonal PbO have been observed and all but one assigned unequivocally by single-crystal techniques: B1g 338.7, A1g 146.5, Eg 321.5 and 81.0, A2u 116, and Eu 243 cm–1. From the i.r. longitudinal and transverse optic (LO and TO) frequencies, the principal components of the di…
Solubilities of sparingly soluble gases in aqueous sodium sulfate and sulfite solutions.
Solubilities of oxygen in aqueous sodium sulfate solutions have been measured at an oxygen partial pressure of 1 atm and temperatures of 15, 25 and 35°C by the gas saturation method. The results are not correlated by the empirical Setschenow equation. The estimated solubility of the system at 25°C by the method of van…
Stereochemical non-rigidity of a metal polyhedron; fourier transform platinum-195 nuclear magnetic resonance spectra of [Pt n (Co) 2n ] 2– (n= 3, 6, or 9)
195 Pt n.m.r. data are reported for [Ptn(CO)2n]2–(n= 3, 6, or 9) and, when n= 9, the spectra are consistent with rotation of the outer Pt3-triangles with respect to the middle triangle about the principal 3-fold axis; inter-exchange of Pt3-triangles occurs in mixtures of [Pt9(CO)18]2– and [Pt12(CO)24]2– at 25°C.
Tailoring closely packed gel–particle systems for use as thickening agents
Abstract When used as a thickening agent in aqueous suspension, hydrolyzed starch–polyacrylonitrile graft copolymer (H‐SPAN) has broadly variable rheological properties, such as viscosity, storage modulus, and stress overshoot characteristics. A series of H‐SPAN preparations with variable swelling ratio Q were made by…
Ultrasonic investigation of anisotropic viscosities in a nematic liquid-crystal
The real part R and the imaginary part X of the shear impedance for the nematic liquid crystal p-n-pentyl p'-cyanobiphenyl (PCB) were measured at 15 MHz. R and X are found to be equal in the nematic phase. Anisotropic viscosity coefficients are deduced from these measurements and the Rapini equality is verified.