Materials Literature
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Following a major shortage of 99Mo in the 2009–2010 period, concern grew that the aging reactor production facilities needed to be replaced. Most producers were using highly enriched 235U (HEU) as the target material. The Organisation for Economic Co-...Read More
A model allowing theoretical prediction of the maximum possible efficiency for any cathode‐ray or x‐ray phosphor is proposed, based on an earlier statistical analysis of e‐h pair generation by van Roosbroeck. The model is independent of the detailed band structure of a particular solid, and predicts the limiting yield…
Abstract Saddle dolomite is a variety of dolomite that has a warped crystal lattice; it is characterized by curved crystal faces and cleavage, and sweeping extinction. Perfect saddle forms have trigonal symmetry, with crystal elongation at high angles to the 'c' axis. Saddle dolomite occurs as both a void-filling ceme…
Abstract A general framework is presented for the quantitative analysis of surfaces by X‐ray photoelectron spectroscopy (XPS or ESCA). The approach starts by considering analysis using reference data recorded on the same instrument and under identical conditions as the analysed sample. Matrix factors are evaluated and…
Tin oxide films have been prepared on glass substrates by spray pyrolysis technique. The electrical and optical properties of undoped and antimony-doped tin oxide films have been studied. The temperature dependence of electron mobility has been analyzed to establish the electron conduction mechanism. Optical propertie…
The oxidation of carbon monoxide catalyzed by Pt(111) was studied in ultrahigh vacuum using reactive molecular beam–surface scattering. Under all conditions studied, the reaction follows a Langmuir–Hinshelwood mechanism: the combination of a chemisorbed CO molecule and an oxygen adatom. When both reactants are at low…
If two materials are brought into contact and then separated they are found to be charged; this is the phenomenon of ‘contact electrification’. The subject falls naturally into three divisions—electrification of metals by metals; of insulators by metals; and of insulators by insulators. The first of these is well unde…
A survey has been made of methods for the synthesis of corroles and their complexes with various metals, and also methods for the synthesis of metal complexes of 1,19-disubstituted octadehydrocorrins from biladienes, bilenes, and bilatrienes and of nickel complexes of 1-substituted octadehydrocorrins by the oxidative…
The EPR linewidth dependence on temperature and impurities concentration in KMn1-xMexF3 single crystals (where Me is Ni2+, Co2+, Fe2+) is investigated both experimentally and theoretically. The theoretical investigation is performed with the use of a nonequilibrium statistical operator method proposed by Zubarev (1971…
Abstract A systematic study of properties of macronet isoporous polymers of styrene offers the following model for their structure: A homogeneous loose highly crosslinked molecular network shrunk in the dry state and relaxed in the swollen one. This model allows to explain the considerable elasticity (changes in volum…
The nonlinear stability of gas bubbles in acoustic fields is studied using a multiple-scale type of expansion. In particular the development of a subharmonic or a synchronous perturbation to the flow is investigated. It is shown when an equilibrium non-spherical shape oscillation of a bubble is stable. If the amplitud…
The fluorescent brightener, Calcofluor White ST, prevents the in vivo assembly of crystalline cellulose microfibrils and ribbons by Acetobacter xylinum. In the presence of more than 0.01 percent Calcofluor, Acetobacter continues to synthesize high-molecular-weight beta-1,4 glucans. X-ray crystallography shows that the…
X-ray diffraction patterns from fibres generally contain a few closely overlapping peaks, each broadened by the contributions of crystallite size, crystallite-size distribution, and lattice distortion. In order to achieve complete characterisation of a fibre by X-ray methods, it is first necessary to separate the indi…
Abstract This paper is a review of x-ray diffraction work in the authors' laboratory to refine the structures of cellulose I and II, and α- and β-chitin, concentrating on the methods used to select between alternate models. Cellulose I is shown to consist of an array of parallel chains, and this conclusion is supporte…
Studies of the anomalous Hall hysteresis loop in the vicinity of Tcomp are carried out to explain whether or not it is caused by the composition gradient across the thickness in amorphous flash evaporated HoCo films. Domain structure appear, when they are magnetized reversal, in the inner as well as in the outer loops…
A method for estimating the number and position of individual thermoluminescence (TL) peaks within a complex glow-curve is described. The method involves partially heating the sample to a temperature TStop cooling to room temperature and re-heating to record all of the remaining glowcurve. The position of the first ma…
Measurements of the electron spin–lattice relaxation rate are reported for Er3+, Dy3+, and Yb3+ in the cubic host Cs2NaYCl6. Expressions for the anisotropic direct relaxation rates of the respective Γ8 and Γ6 ground states are given in terms of the eleven coupling parameters of the dynamic orbit–lattice interaction fo…
Using a simple Ginzburg-Landau theory which incorporates the crystal symmetry of Nb${\mathrm{Se}}_{3}$, we show that the approximate relation, $2({\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}}_{1}+{\stackrel{\ensuremath{\rightarrow}}{\mathrm{k}}}_{2})\ensuremath{\simeq}(1, 1, 1)$, between the two charge-density-wav…
We have measured the temperature dependence of the hydrogen spin lattice relaxation time in the hydride (β, β′, γ, δ) and solid solution phases of the Mg2NiHx system. These gave the temperature ranges of the various phases. The hydrogen diffusion activation energy for the β, β′, γ and δ hydride phases were found to be…
It has been shown that the $D$ band in alkali halides containing ${s}^{2}$ ion (${\mathrm{Tl}}^{+}$, ${\mathrm{In}}^{+}$, ${\mathrm{Ga}}^{+}$, ${\mathrm{Sn}}^{2+}$) is composed of three bands (named ${D}_{1}$, ${D}_{2}$, ${D}_{3}$ in the order of increasing energy). Of the three bands, the ${D}_{1}$ band is the weakes…