Materials Literature
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Rubbers are long-chain molecules which are plastic in nature in the raw or unvulcanized state. Vulcanization is an irreversible process by which the predominantly plastic rubber is converted to predominantly elastic and a three-dimensional network structure through the anchoring between two polymer chains. Chemically,…
The gaseous molecule CrPO2 has been investigated in the course of a high-temperature mass-spectrometric Knudsen-cell study of the vapours over an europium–chromium–phosphorus–oxygen system. From the enthalpy of the equilibrium reaction CrPO2(g)= CrO(g)+PO(g) and appropriate ancillary data, the atomization energy of th…
Precipitation of σ phase in an Fe-25Cr-7Ni-3Mo alloy with a duplex structure of α and γ phases, has been studied systematically by means of optical microscopy, X-ray diffraction, hardness measurement, tensile test, SEM observation and dilatometric measurement. The results obtained in this study are as follows: (1) TTT…
We report measurements of the resistive superconducting transitions of NbSe3 as a function of magnetic field for sufficient pressures to destroy the lower CDW. These indicate that NbSe3 is a bulk anisotropic superconductor with a total Meissner effect. The critical field anisotropies are well described by an effective…
The use of electrochemical techniques to measure chemical-diffusion coefficients in solid alloys is reviewed. The theoretical basis and experimental aspects of four different approaches are discussed in detail: the potentiostatic, galvanostatic, potentiometric, and steady- state ac methods. As an example, all four of…
The infrared absorption spectra of natural zeolites of the 7th structural group: heulandite, clinoptilolite, brewsterite, and stilbite were measured. The spectra were taken in the wavenumber region 200—4000 cm by the KBr technique (1 :40). The number and symmetry of individual vibrations were ascertained by theoretica…
The current ‘dish’ techniques for measuring the moisture-vapour permeability of textile fabrics are slow and tedious. A new approach, based on the measurement of the relative-humidity gradient in a closed linear system, is described. This Resistance Tube provides results that are equivalent to those of the dish techni…
General theoretical expressions appropriate to calculating the internal and external quantum efficiency of photoluminescence (PL) are derived for a semiconductor of thickness d and bounded by two surfaces with different surface-recombination velocities. The external efficiency expected from thin and thick layers is co…
15 N N.m.r. spectroscopic results are reported for a range of covalent azides RNαNβNγ(where R is perfluoroaryl, perfluoro- or chlorofluoro-pyridyl or -pyrimidinyl, or trimethylsilyl), and compared with literature values for related azides. The Nα and Nγ chemical shifts vary over a range of 80–100 p.p.m., and correlate…
Рффект гигантского комбинационного рассеяния света молекулами, адсорбированными РЅР° поверхности металла, Емельянов Р’.Р
The thermal stress resistance of aluminas is strongly influenced by the surface heat transfer coefficient (h). In liquid quenches, h, which is a function of boiling phenomena, varies with bath and sample temperature. Thus, while a 22°C water quench yields ΔT c values essentially independent of the alumina properties o…
On the basis of the high-pressure polymerization of ethylene, in which organic peroxides are increasingly used as initiators, the problems which play an important part in selecting the most suitable initiators are discussed. Starting from the rate of decomposition of the initiator at the actual conditions of the high-…
Preface. Chapter 1 Introduction . Chapter 2 History 2.1 Outline 2.2 Wire-braced structures 2.3 Semi-monocoque structures 2.4 Sandwich structures 2.5 Review of the key points. Chapter 3 Parts of the Aircraft 3.1 Terms connected with flight 3.2 Terms connected with control 3.3 Terms connected with high-lift devices 3.4…
Methyl viologen quenches the singlet excited state of a positively charged magnesium phthalocyanine but not the triplet excited state. In aqueous solution, the singlet quenching rate constant depends upon ionic strength but at zero ionic strength it approaches the diffusion-controlled limit. Overall, the quenching act…
Abstract Chitin was obtained from shell of the tail portions of the prawn Nephrops norvegicus (L) and was deacetylated to give chitosan. The adsorption and diffusion of copper (II) ions were studied and the diffusion of the acid dye CI Acid Orange 10 through chitosan films containing different amounts of chelated copp…
Kinetic studies on the decomposition of a flexible polyurethane foam based on tolylene diisocyanate and a polyether polyol of propylene oxide have been carried out with the thermogravi-metric technique (TGA). In dry nitrogen the decomposition proceeds in two overall steps. At the end of the first step, which follows a…
Embrittlement of Zircaloy-4 cladding by oxidation of the inner surface occurring in an LWR loss-of-coolant accident was studied using simulated fuel containing of A12O3 pellets sheathed in Zircaloy-4 specimen cladding, filled with Ar gas, and sealed. This simulated fuel rod was heated from outside until the isothermal…
Abstract A survey of the Raman and infra red data for the layered structure InSe shows that there is no agreement upon its crystallographic structure. The polytypes, β, ε, and γ are equally invoked by the various groups. Some experiments on samples from different laboratories are repeated. Infrared transmission at dif…
Experimental and theoretical studies have been made of losses in Nb/Ti multifilamentary composite exposed to transverse alternating and rotating fields. Analytical expressions for eddy current losses inside the copper matrix can be found. As for hysteresis losses, an analytical expression can only be obtained in low a…
A method for describing cubic giant cells is proposed. The structures may be regarded as arrangements of nested polyhedra units, isolated or linked, centred at sites of high point symmetry. Five basic types of nested polyhedra units, taken from well known cubic structures are defined: α-Mn (29 atoms), BCC (27), γ-bras…