Some aspects of the light protection of polymers
Abstract
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Stress Corrosion Spectrum
Despite many attempts over the years to rationalise stress corrosion cracking in terms of a single mechanism, it is proposed that the growing body of evidence more readily supports a continuous spectrum of mechanisms. Thus, it is suggested that in those systems of metal and environment where the conditions are between…
Differential Thermal Analysis
Differential thermal analysis (DTA) is an instrumental technique used for studying the physical and chemical changes that occur in materials as they are heated or cooled. When a material undergoes a physical change, such as melting or crystalline transformation, or when a chemical reaction occurs, energy is either abs…
Nitrogen‐containing products from the thermal decomposition of flexible polyurethane foams
Abstract The thermal decomposition of a polyester and a polyether flexible foam in a nitrogen atmosphere has been studied by gas chromatography, mass spec‐trometry and elemental ultramicroanalysis. It is shown that the decomposition behaviours of the two foams are similar. At low temperatures (200 to 300 °C) there is…
The Shape Memory (‘Marmem’) Effect in Alloys
The shape memory effect, by which a material, apparently plastically deformed, reverts to its original shape upon heating to some higher temperature, has been reviewed and discussed from the point of view of the crystallography of martensitic transformations. Considering the general characteristics of martensitic mate…
The Dentinal Tubules and the Odontoblast Processes a Scanning Electron Microscopic Study
Scanning electron microscopy of the dentinal tubules and the odontoblast processes was performed on young premolars that had been fractured to open the tubules in the crown dentine parallel to theiraxis. The tubules were viewed in an outward direction, starting from the attached pulp tissue at the buccal pulp horn. Th…
Design Parameters for the Cylindrical Mirror Energy Analyzer
Design parameters are presented for various geometrical arrangements of the cylindrical mirror electron energy analyzer. The theory and operation of this high quality instrument are discussed and compared with an experimental device. Similar properties of a parallel plate analyzer with second order focusing are review…
[Physiological and biochemical contributions to the taxonomy of the genus Chlorella. VI. Utilization of organic carbon compounds].
Es wurde die Verwendbarkeit von Acetat, Glucose, Fructose, Galactose, Saccharose und Lactose als Kohlenstoffquelle fur das Wachstum von 72 Chlorella-Stammen, die 10 autotrophen Taxa angehoren, untersucht. Im Dunkeln zeigen mit Acetat 34 Stamme und mit Glucose 37 Stamme gutes Wachstum (Chlorella kessleri, die meisten S…
A structural model for the amorphous state of polymers: Folded-chain fringed micellar grain model
A more realistic, two-phase structural model is proposed for the amorphous solid state of polymers. The model is based on structural evidence reported to date, in particular the evidence from our own electron diffraction and microscopy studies of crystallizable and non-crystallizable amorphous polymers, including near…
Complexes of some alkali-metal and silver salts with 1,4-dioxan
The 1,4-dioxan (dx) complexes NaClO4,3dx, NaBF4,3dx and NaI,3dx have the cubic structure of AgClO4,3dx. The metal ion is octahedrally co-ordinated by oxygen atoms from dioxan with Na–O distance 2·43—2·46 Å, identical to those found in Na(OH2)6 octahedral Size and shape requirements limit the anions found in complexes…
Deposition of Aluminum from an Electron Beam Source
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Edward B. Graper; Deposition of Aluminum from an Electron Beam Source. J. Vac. Sci. Technol. 1 Ja…
Quasichemical equilibrium approach to crosslinked polymer solutions
Abstract Thermodynamic functions for mixing of a solvent with a crosslinked (branched) polymer are derived by considering the primary chains as copolymers of crosslinked and uncrosslinked units. Primary chains and solvent molecules are placed on a lattice with coordination number z. The crosslinked units bear one cros…
Substituent-dependency of cis–trans-isomerization in disubstituted tetrabenzopentafulvalenes
The conformational behaviour of 1,1′-disubstituted tetra benzopentafulvalene is strongly substituent-dependent; in the 2,2′-difluoro-derivative, the energy barriers associated with the cis–trans-isomerization did not prove to be low.
The structure of solutions and films of cellulose acetate
Abstract The optical rotatory dispersion of solutions of cellulose acetates with different degrees of acetylation in a series of solvents is studied. Increasing the degree of esterification of the cellulose acetate results in a shift of the optical rotation to more negative values. These changes have been explained on…
INVESTIGATION OF THE MAGNETIC PHASE TRANSFORMATION IN Mn3Sn
The transformation between a long‐period antiferro‐magnetic and a triangular‐type weak ferromagnetic phase was investigated by magnetic, x‐ray and neutron diffraction methods on polycrystalline and single‐crystal samples of non‐stoichiometric Mn3Sn with hexagonal DO19 structure. The transition is of first‐order, being…
Thermophysical Properties of Matter - The TPRC Data Series. Volume 8. Thermal Radiative Properties - Nonmetallic Solids
Abstract : The TPRC Data Series published in 13 volumes plus a Master Index volume constitutes a permanent and valuable contribution to science and technology. This 17,000 page Data Series should form a necessary acquisition to all scientific and technological libraries and laboratories. These volumes contain an enorm…
On the Symmetry of OD‐Structures Consisting of Equivalent Layers
Abstract After some introductory remarks a survey is given (in part 2) of the basic notions of OD‐theory, including the concept of the OD‐groupoid family. In part 3 a new procedure is presented for the determination of the OD‐groupoid family of an OD‐crystal from general features of its X‐ray diagrams and applied to t…
The Aluminum Electrode in AlCl[sub 3]-Alkali-Halide Melts
Passivation phenomena have been observed upon cathodic and anodic polarization of the Al electrode in AlCl 3 ‐ KCl ‐ NaCl melts between 100° and 160 °C. They are caused by formation of a solid salt layer at the electrode surface resulting from concentration changes upon current flow. The anodic limiting currents incre…
Influence of framework charge density on ion-exchange properties of zeolites
Ion-exchange isotherms have been measured at 25°C for the high framework charge chabazite-type zeolite, K-G1, and involving the cation pairs: K+⇌ Na+, Na+⇌ Li+, Na+⇌ Cs+, Na+⇌ Ca2+, Na+⇌ Sr2+, and Na+⇌ Ba2+. The results have been compared with those for an isostructural natural chabazite of lower charge density. The v…
Étude par effet Mössbauer de l'ion Fe2+ en symétrie trigonale dans les composés du type (Fe, M)2Mo3O8 (M = Mg, Zn, Mn, Co, Ni) et propriétés magnétiques de (Fe, Zn) 2Mo3O8
Dans les composés considérés, isomorphes de Zn2Mo3O8, les cations divalents Fe2+ et M2+ se répartissent dans des sites octaédriques ou tétraédriques de symétrie trigonale. L'occupation des différents sites, ainsi que les propriétés électroniques et magnétiques des ions Fe 2+ dans chacun des sites ont été déduites de l…