Polyurethane Elastomers in Surgery
Review of polyurethane elastomers and several applications as surgical implants.
Materials Literature
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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.
The production and subsequent relaxation of vibrationally excited OH in the reaction of atomic oxygen with HBr
Abstract A fast discharge flow apparatus equipped for EPR detection of radicals has been used to investigate the reaction O + HBr → OH + Br. At 295°K, measurements showed that more than 97% of all OH produced in this reaction was formed initially in its first vibrationally excited state. Rate constants for physical de…
Purification and some properties of polyethylene adipate-degrading enzyme produced by Penicillium sp. strain 14-3.
Polyethylene adipate (PEA)-degrading enzyme of Penicillium sp. strain 14-3 was purified by precipitation with ammonium sulfate and chromatography with CM-Sephadex C-50. The purified enzyme was confirmed to be homogeneous by ultracentrifugal analysis and polyacrylamide gel electrophoresis. Some properties of the purifi…
pH-Induced co-ordination geometry change in a macrocyclic nickel(II) complex
The co-ordination geometry of the NiII complex with the new macrocyclic ligand L, which contains a side chain, is controlled by the pH of the solution, the square-planar yellow diamagnetic form and the octahedral blue paramagnetic one being stable below and above pH 6·3, respectively.
Kernel Migration for HTGR Fuels from the System Th‐U‐Pu‐C‐O‐N
Nuclear fuels for the high‐temperature gas‐cooled reactor (HTGR) consist of spherical kernels of actinide compounds contained in gaslight pyrolytic carbon and SiC. The fuel kernels migrate up the temperature gradient and into the coating layers. A theoretical analysis of in‐reactor migration data indicates that a soli…
A Practical Process for the Preparation of Super Slurper, a Starch‐Based Polymer with a Large Capacity to Absorb Water
Abstract The solid, water‐insoluble sorbent called Super Slurper that swells in water is a base hydrolyzed starch‐polyacrylonitrile graft copolymer in which the nitrile functionality has been converted to a mixture of carboxamide and alkali metal carboxylate. A process for making the polymer in multipound quantities h…
Some Reactions of OH(v = 1)
Abstract Reactions of OH( v = 1) with HBr, O, and CO have been studied at 295°K using a fast discharge flow apparatus: equation image The reaction O + HBr → OH( v = 1) + Br was used as a source of OH( v = 1), and subsequent chemical reactions of the excited radical were followed using EPR spectroscopy. Rate constants…
Structure and bonding in gold( I ) compounds. Part 2. Mössbauer spectrum of linear gold( I ) complexes
Mössbauer data for a large number of gold(I) complexes are presented. From these data and previously published work it is concluded that: (i) the bonding involves only 6S and 6p orbitals; (ii)π acceptance by ligands from gold is negligible; (iii) the gold atom tends to concentrate S character in bonds to such ligands…
Irradiation Growth of Zircaloy
Data on irradiation growth of Zircaloy is presented. Irradiation growth is defined as irradiation-induced changes in dimensions in the absence of an applied stress. It is shown that the primary variables are fluence, irradiation temperature, amount of prior cold work, heat treatment, and texture. For recrystallized Zi…
Electron spin resonance of symmetrical three-spin systems in nematic liquid crystals
The Alexander-Kaplan method is applied to analyse the E.S.R. spectra of symmetrical three-spin systems, undergoing fast, intermediate and slow rotational diffusion in nematic liquid crystals. Particular emphasis is given to the slow-motional region. The line shapes are calculated from a spin hamiltonian, which conside…