Materials Literature
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The changes in the properties of copolymers as a function of the introduction of units with carboxy- and salt groups into the macrochain are examined. Attention is concentrated on the analysis of the results of the study of copolymers in the acid and ionomeric forms in solutions. The decisive influence of ionic intera…
The quenching by an electric field of molecular-orientation fluctuations in freely suspended ferroelectric smectic-$C$ films has been studied by light scattering, allowing absolute measurements of polarization, elastic constants, and viscosities. Evidence is presented to demonstrate surface contributions to Frank elas…
Preface 1. Background to ceramics 2. Elastic behaviour 3. Fundamentals of fracture chemicals 4. Geometrical aspects of dislocations 5. The flow stress and plastic flow 6. The fracture strength of ceramics 7. Impact resistance and toughness 8. Thermal stresses and fracture in ceramics 9. Engineering design data Referen…
Optical and EPR measurements of tetragonal symmetry erbium-fluoride, erbium-hydride, erbium-deuterium and erbium-tritium ion pairs in calcium fluoride are reported. A crystal-field analysis accounts for the observed 4f 11 multiplet splittings and for the g-values obtained by EPR and Zeeman spectroscopy. The isotope sh…
The intensity of the exciton-magnon combination band at 631 nm in the ionic ferromagnet Rb 2 CrCl 4 has been measured as a function of temperature from 0.85 to 3.6K and as a function of magnetic field (up to 5 T in the (100) direction) at temperatures from 2.1 to 4.2K. The zone-centre magnon gap is estimated as 1.4+or…
The Auger electrons and the X-rays emitted in XPS are treated in a unified manner with the photoelectrons as a one-step process, without distinguishing between primary photoionisation and secondary Auger and X-ray emission. Such a formulation will be capable of treating relaxation and interference effects in a consist…
High-resolution M 4,5 N 4,5 N 4,5 Auger and M 5 and valence-band photoelectron spectra of Ag, Cd, In and Sn, measured using X-ray excitation, are combined to yield the magnitude of U eff , the Coulomb repulsion between two holes on the same atomic site. The extra-atomic relaxation contributions to Auger and photoelect…
At low temperatures, low dimensional metals are commonly found to exhibit superlattices incommensurate with the primitive lattice (periodic lattice distortion coupled to charge density waves, PLD — CDW). Transitions to such states are driven by strong electron phonon coupling and favoured by the particular forms of th…
The structural phase transitions occurring in PbZrO 3 have been investigated using X-ray diffraction and dielectric constant measurements. The lattice parameters, Pb ion displacements and ZrO 6 octahedral tilts in the antiferroelectric, orthorhombic phase have been determined as functions of temperature between 20 and…
Space-filling models of yeast hexokinase, adenylate kinase, and phosphoglycerate kinase drawn by computer clearly portray the bilobal character of these phosphoryl transfer enzymes, and the deep cleft which is formed between the lobes. A dramatic conformational change occurs in hexokinase as glucose binds to the botto…
Non-radiative energy transfer from optically excited Dy3+ to Ho3+ is studied in calibo glass. An experimental investigation is made to the nature of excited Dy3+ donors in presence of Ho3+ acceptors. The time dependence of luminescence decay following the pulsed excitation illustrates the transient behaviour, characte…
An X-ray study is made of the high-temperature and low-temperature phases of Ni(NH3)6(ClO4)2. At room temperature, the unit cell is regular, of the CaF2 type, with lattice constant ac = = 11.44 Å. The monoclinic cell of the low-temperature phase has, at T = 100 K, the constants am = (8.19 ± 0.01) Å, bm = (11.76 ± 0.01…
The structure and properties of grain boundaries are considered during superplastic deformation on the basis of recent concepts of the interaction between lattice dislocations and grain boundaries. It is shown that the boundaries contain both, lattice and grain boundary dislocations. The presence of these extraneous d…
The magnetization behaviour is investigated in a pulsed magnetic field up to 50 kOe at 80 ≦ T ≦ ≦ 220 K for hydrogen solid solutions in Fe65(Ni1–xMnx)35 invars containing 0, 4.5, 10, 17, 24, 29, and 35 wt% Mn. The alloys are enriched in hydrogen to hydrogen/metal atomic ratio n ⪅ 1 using exposures to PH2 ≦ 70 kbar. Th…
The optical anisotropy induced in films of some chalcogenide vitreous semiconductors (ChVS) by linearly polarized light is studied. The spectral responses of the photoinduced dichroism are compared with the transmission spectra of the illuminated films. The phenomenon of photoinduced anisotropy is associated with the…
The present investigation deals with amorphous polystyrene crazing behavior at both the molecular and macroscopic levels. The nature of the amorphous state is considered from the perspective of statistical fluctuation theory, especially when a mechanical force field is acting on the polymer. Past crazing studies have…
The electronic state of CuCr 2 Se 4 is investigated by means of the polarized neutron diffraction technique. From the measured form factors of copper and chromium atoms, the magnetic moments are determined to be -0.07±0.02 (µ B /Cu) and 2.64±0.04 (µ B /Cr), respectively. Further, the uniform polarization existent thro…
Ultrasonic velocities and attenuations of Rb 2 ZnCl 4 were measured as functions of temperature. The observed anomalies of the velocities are discussed in relation to the incommensurate soft mode.
An experimental study of shear viscosity η(\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma $\end{document}), principal normal stress difference N1(\documentclass{article}\pagestyle{empty}\begin{document}$ \dot \gamma $\end{document}), storage modulus G′(ω), dynamic viscosity η′(ω), and filament e…
A phenomenological thermodynamic model suited for the interpretation of the high spin⇌low spin transition in solid transition metal complexes is described. The model is based on the idea of the spin transition taking place through a significant phonon-assisted coupling between the electronic state of the primary spin…