The domain structure formation at phase transitions
The connection between the phase transition conditions and the domain structure of BaTiO3 and PbTiO3 crystals is determined.
Materials Literature
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Domain-wall orientations and domain shapes of ferroelectric TGS and TGSe crystals
Wall-energy density as a function of wall orientation has been calculated on the basis of Zhirnov-type domain-wall theory. The equilibrium wall-orientations and the domain shapes which are consistent with the experimental observations have been successfully brought about for TGS and TGSe crystals. Two preferential ori…
Picosecond Pulse Stroboscopic Scanning Electron Microscope
The stroboscopic SEM has been developed to observe the two-dimensional dynamic voltage contrast images of semiconductor devices in the nanosecond and picosecond regions. It consists of a usual SEM and a pulse gate which is inserted between the electron gun and the condenser lens. The shortest beam pulse width is 0.2 p…
Analysis of Fracture Morphology of Hydrogen-Assisted Cracking in Steel and Its Welds
The relationships between fracture morphology of hydrogen-assisted cracking, microstructure, and crystallographic orientation were investigated using the scanning electron microscope. In the fracture morphology of hydrogen-assisted cracking, quasicleavage fracture, intergranular fracture, and dimple rupture were obser…
Structure Determination by X-Ray Crystallography
M F C Ladd and R A Palmer New York: Plenum 1977 pp xvi + 393 price $35.40 For several years the University of Surrey and Birkbeck College, London, have been running teaching courses in crystallography. Therefore a book written by Ladd (Surrey) and Palmer (Birkbeck), who have both been intimately involved in these cour…
Infrared study of the adsorption of anisoles on silica immersed in heptane
Infrared spectra have been reported of silica immersed in solutions of anisole, six substituted anisoles (4-nitro, 4-chloro, 4-bromo, 4-methyl, 2-fluoro and 2,6-dimethyl), nitrobenzene and 4-nitrotoluene in heptane. Surface silanol groups were perturbed by hydrogen bonding interactions with either methoxy-groups or th…
Spinodal decomposition, ordering, and discontinuous precipitation in deformed and aged copper-titanium alloys
Phase transformations in quenched, deformed, and aged copper-titanium alloys containing up to 5,6 at.-% Ti were studied by means of hardness measurements and electron microscope examinations of thin foils. The modulation wavelength showed a linear relationship with the logarithm of the aging time. Deformation caused a…
Polymer processing: the physics of stretching chains
Recent developments in the physical understanding and the achievement of high chain extension in polymeric material which could lead to significant advances in existing and new areas of polymer processing technology are described. Solid-state deformation and melt and solution orientation are outlined
Preparation and characterization of head‐to‐head polymers. VIII. Head‐to‐head poly(vinyl cyclohexane)
Abstract Head‐to‐head poly(vinyl cyclohexane) (H‐H PVCH) was prepared from 2,3‐diphenylbutadiene, which was polymerized by radical, 1,4 polymerization to poly(2,3‐diphenylbutadiene) and then catalytically hydrogenated to H‐H PVCH, H‐H PVCH was also prepared by catalytic hydrogenation of H‐H polystyrene (PS). The catal…
Effects of Grain Size and Specimen Thickness on Mechanical Properties of Polycrystalline Copper and Copper-Aluminum Alloy
Mechanical properties of polycrystalline copper and Cu-13 at%Al alloy have been investigated as a function of grain size and specimen thickness at room temperature, with the following results: (1) The flow stress of both copper and Cu-13 at%Al alloy decreases as the ratio of specimen thickness to grain size decreases…
Photoelectric phenomena in single crystals of some perovskite oxides
Photoconductivity (PQ and thermally stimulated conductivity (TSC) were investigated on some single-crystal perovskite oxides. Using PC spectral dependence, band gap and impurity-level depths were found. The TSC method gave further information about the energy spectrum of local levels. Due to a significant PC and deep…
Physical properties of nematic p,p'-diheptylazobenzene
The elastic constants, magnetic susceptibility, refractive index and density are reported for p,p'-diheptylazobenzene. The behaviour of the elastic constants of this non polar compound is very similar to that of related polar compounds. The anisotropy of both the static and the high-frequency permittivity is proportio…
Stepwise base decomposition of 12-tungstosilicate(4–)
The reaction of [SiW12O40]4–(1.5 × 10–5 mol dm–3) with excess of hydroxide ion at an ionic strength of 1.0 mol dm–3 MCl, to form [SiO4]4– and [WO4]2–, has been studied. The reaction proceeds in three distinct stages, the intermediates being [SiW11O39]8– and [SiW9O34]10–. The first stage proceeds via a base-dependent p…
Non-linearities and fluctuations at the threshold of a hydrodynamic instability in nematic liquid crystals
In nematics, the simple shear flow may become unstable when the director is perpendicular to the shear plane. Here we study the non-linear regime above the threshold of the Homogeneous Instability [1]. We use a perturbative approach derived from exact equations within the framework of the Frank-Ericksen-Leslie continu…
Development of a Hot-Stamping Brass Resistant to Dezincification
A hot-stamping brass immune to dezincijication has been developed. The recommended composition is 35·0–37·0% zinc, 1·7–2·7% lead, 0·08–0·12% arsenic, remainder copper. The alloy contains sufficient beta phase at the hot working temperature (∼820°c) to ensure adequate formability. After stamping, a heat treatment, usua…
Photolysis of periodate and periodic acid in aqueous solution
The photochemistry of periodate and periodic acid in aqueous solution was studied (i) by quantum yield measurements at low light intensity (ii) by flash photolysis, and (iii) by photolysis of glassy samples at 77 K. The photochemical studies were supplemented with pulse radiolysis studies of aqueous periodate solution…
Identification of the species [Te n Se 4–n ] 2+ by high resolution 125 Te and 123 Te Fourier transform n.m.r. spectroscopy
High resolution 125Te and 123Te F.T. n.m.r. spectroscopy have been used to identify all members of the series [TenSe4–n]2+(n= 1–4) in the Te–Se–oleum system.
Dielectric and magnetoelectric properties of Bi2Bi4Fe2Ti3O18
The temperature dependence of the permittivity of BTF 2 ceramic has been measured. Three singularities have been observed, of which two at 898°C and 752°C correspond to displacive phase transitions leading to the sequence paraelectricm ↔ ferroelectric ↔ ferroelectric. The third feature, around 400°C, is tentatively as…
The Fission Cross Sections of Uranium-234 and Uranium-236 Relative to Uranium-235
Fission cross-section ratio measurements were made in the 2- to 3-MeV region using 235U samples with 234U and 236U samples containing ∼10% 235U. Atom ratios were obtained from measured thermal fission ratios and the isotopic analysis and also by alpha counting. Shape measurements were made from threshold to 10 MeV usi…
Induced and spontaneous optical activity in Pb 5 Ge 3 O 11 single crystals
Temperature dependences of the optical rotatory power ρs 3 in the ferroelectric phase, the field-induced optical rotatory power ρ3(E 3) in the paraelectric phase and of the initial permittivity ε33 have been measured. These results show that dρ3/dE 3 fulfils the Curie-Weiss law being proportional to the value of ε33.…