Structural aspects of co-ordinated nitrate groups
C. C. Addison, N. Logan, S. C. Wallwork and C. D. Garner, Q. Rev. Chem. Soc., 1971, 25, 289 DOI: 10.1039/QR9712500289
Materials Literature
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Elements of polymer degradation
A survey of the degradation of polymer structures through thermal, oxidative, radiative, mechanical, chemical and biological means is presented. Examples, data and equations are largely based on synthetic polymer analyses, but the essential theories of polymer degradation are presented. -- AATA
Structures cristallines de deux zéolithes de type y cériée et protonée, CeHY
Les structures de la zéolithe CeHY de composition Ce8,3, Na8,1, H23, Al56, Si136, O384 déshydratée par chauffage sous vide (structure I) et déshydratée par chauffage à l’air (structure II) ont été déterminées à partir de leur diagramme de diffraction Debye-Scherrer. Dans la structure 1,75 % des ions cérium occupent le…
Structures cristallines de trois zéolithes de type Y partiellement décationisées, (Na26,6H29,4)Y, (Na14,2H41,8)Y, (Na2,2H53,8)Y
Les structures cristallines des zéolithes synthétiques de type Y partiellement décationisées
The Shape-Memory Effect in a Titanium-35 wt.-% Niobium Alloy
The shape-memory effect has been studied in a titanium −35 wt.-% niobium alloy. The effect is observed under two different sets of conditions. First, when the fully martensitic alloy is deformed below Ms it recovers its original shape when heated above As Secondly, if the alloy is deformed between Ms and As (with Ms a…
Magnetic effects on triplet exciton interactions
Abstract
Optical and Electrical Properties of SrAl[sub 2]O[sub 4]:Eu[sup 2+]
It has been shown that the optical and electrical properties of Sr 0.95 ± x Eu 0.05 Al 2 O 4 ± x depend on composition. A composition with excess alumina was found to have the highest CR efficiency, photoconductivity, and a long‐lasting persistence. A mechanism is proposed which assigns the delayed luminescence to a p…
Carbides: Properties, Production, and Applications
I The Structure and Physicochemical Properties of Carbides.- Structures.- Thermodynamic and thermophysical properties.- Electrophysical and magnetic properties.- Physicomechanical properties.- Chemical properties.- II Methods of Producing Carbides.- III Carbides of Metals of Group I.- Carbides of the alkali metals.- C…
Heteropolytungstate complexes of the lanthanide elements. Part I. Preparation and reactions
Salts of the anions LnIIIW10O357–(Ln = La, Ce, Pr, Nd, Sm, Ho, Er, Yb, and Y) and CeIVW10O356– have been prepared and analysed. The formulae of the previously reported 8-tungstocerates are revised. All the anions are unstable outside the pH range 5·5–8·5, and stable solutions of the free acids cannot be obtained. Lant…
Further considerations of non symmetrical dielectric relaxation behaviour arising from a simple empirical decay function
The empirical dielectric decay function ϕ(t)= exp –(t/τ0)β, 0< β⩽1 has been transformed analytically and numerically into the frequency dependent complex dielectric permittivity. It is shown that empirical curves give a very satisfactory representation of the dielectric α relaxations observed in polyethyl acrylate, po…
Poole-Frenkel conduction in amorphous solids
The nature of the electrical conduction process in amorphous solids, using as a basis the ionization of local defects by an applied field, is investigated. It is shown that the Poole-Frenkel effect is a limiting case of a more general analysis that can be extended to cover the experimentally available range of field s…
Acidic and basic properties of hydroxylated metal oxide surfaces
Hydroxyl groups on the surface of metal oxides are amphoteric in character. From experiments with anatase, rutile, η-alumina, α-Fe2O3,CeO2, and SnO2, half the OH groups are acidic in character, the other half are mainly basic and may be exchanged for other anions. This behaviour is explained by the structure of the hy…
Application of Ferrite to Electromagnetic Wave Absorber and its Characteristics
An electromagnetic wave absorber utilizing ferrite or rubber ferrite composed of ferrite powder and rubber is described. In our investigation, the existence of a matching frequency f/sub m/ and a matching thickness t/sub m/ has been found. The terms f/sub m/ and t/sub m/ mean that the ferrite which is backed with a co…
Hot‐Pressed (Pb,La)(Zr,Ti)O 3 Ferroelectric Ceramics for Electrooptic Applications
Transparent ferroelectric ceramic materials suitable for a variety of electrooptic applications were found in the quaternary (Pb,La)(Zr,Ti)O 3 system. These PLZT materials are prepared from mixed oxides and hot‐pressed typically at 1100°C for 16 h at 2000 psi. Modifying the lead zirconate‐titanate system with lanthana…
Calculation of interfacial tension in polymer systems
Abstract We propose an equation, based on “reciprocal” mean and force additivity, for calculating the interfacial tension between polymers or between a polymer and an ordinary liquid: where γ 12 is the interfacial tension; γ i the surface tension; γ and γ the dispersion and polar components of γ i , respectively. This…
Textbook of polymer science
The Science of Large Molecules POLYMERIZATION Step-Reaction (Condensation) Polymerization Radical Chain (Addition) Polymerization Ionic and Coordination Chain (Addition) Polymerization Copolymerization Polymerization Conditions and Polymer Reactions CHARACTERIZATION Polymer Solutions Measurement of Molecular Weight an…
Spectra of some self-exciting and mutually exciting point processes
In recent years methods of data analysis for point processes have received some attention, for example, by Cox & Lewis (1966) and Lewis (1964). In particular Bartlett (1963a, b) has introduced methods of analysis based on the point spectrum. Theoretical models are relatively sparse. In this paper the theoretical prope…
Correlated Small-Polaron Hopping Motion
Prior small-polaron hopping theories have tacitly assumed that the lattice relaxes rapidly enough after a jump to permit the treating of successive hops as independent. We conclude that the appropriate relaxation time is too long to permit consistent application of these theories to intermediate-mobility materials suc…
A nonlinear stability analysis of the freezing of a dilute binary alloy
Abstract An investigation is made of the stability of the shape of a moving planar interface between the liquid and solid phases in the freezing of a dilute binary alloy. A nonlinear model is used to describe an experimental situation in which solidification is controlled so that the mean position of the interface mov…
Cooperative Luminescence in YbPO4
YbP${\mathrm{O}}_{4}$ was found to show weak green (497 nm) luminescence when excited by infrared (1 \ensuremath{\mu}m) light. It is concluded, on the basis of measurements of excitation intensity dependence and decay time, that this luminescence is due to the emission of a photon by a pair of excited ${\mathrm{Yb}}^{…