Materials Literature
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Near-edge x-ray-absorption fine-structure studies of ${\mathrm{O}}_{2}$ chemisorbed on Ag(110) and Pt(111) surfaces near 100 K reveal different predissociation stages of molecular oxygen. ${\mathrm{O}}_{2}$ on Ag(110) exhibits only a ${\ensuremath{\sigma}}^{\mathrm{*}}$ resonance and resembles a single-bonded peroxo s…
We have measured the thermal conductivity of polymethylmethacrylate (PMMA), amorphous ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$, Ca-K nitrate glass, three ${\mathrm{SiO}}_{2}$-based glasses, and glycerol in the temperature range 30--300 K, using an ac technique that eliminates errors from blackbody radiation. This techniq…
It is shown how the results of low-temperature electrical and thermal conductivity measurements may be used to characterise and determine the defect structure of pristine and intercalated carbon fibres of various origins.
The aromatic (A) and quinoid (Q) forms of polythiophene (PT) have entirely different energy gaps: ∼0.5 eV for the quinoid form and ∼2 eV for the aromatic form, respectively. The energy gaps and stability of derivatives of PT are studied by total MNDO geometry optimization using energy band theory for the total energy…
The discrete scale invariance of quasi-periodic systems leads to a scaling relationship Omega =L -z f(L) between a characteristic dynamic variable Omega and length L, where f(L) is a periodic function of ln L. The dynamic exponent z can be calculated for diffusion, spin wave and phonon dynamics (where Omega is respect…
Radiation effects of X-rays in zircon (ZrSiO 4 ) single crystals were studied at RT, by analysing the kinetics and spectrum of the thermoluminescence between 20 degrees and 420 degrees C. The results indicate that some of the electrons produced by the irradiation are captured by Dy 3+ impurities apparently substitutin…
A 2D Ni-Cr quasicrystal displaying a twelvefold symmetry consists of a dodecagonal quasiunit cell (QUC) which is an intergrowth of ${\mathrm{Zr}}_{4}$${\mathrm{Al}}_{3}$ and ${\mathrm{Cr}}_{3}$Si structures. If the QUC is represented by a geometric point, then this quasicrystal can be described by a quasilattice deriv…
Abstract This paper is a review of leading research in the field of bacterial corrosion monitoring with specific emphasis on systems that transport liquids rather than gases. However, the principles of bacterial corrosion presented below are universal and independent of whatever media is transported through the pipeli…
The phase separation of a binary liquid mixture contained in a rigid porous medium has been investigated by study of the light scattered at 90\ifmmode^\circ\else\textdegree\fi{} from a porous glass rod containing a critical mixture of n-${\mathrm{C}}_{6}$${\mathrm{H}}_{14}$+n-${\mathrm{O}}_{6}$${\mathrm{F}}_{14}$. Evi…
Abstract Accelerated corrosion experienced in the overhead system of an atmospheric crude distillation column has been analyzed to determine the cause of the corrosion occurring at temperatures above the aqueous dew point. Results of field monitoring tests, laboratory tests and thermodynamic considerations all confirm…
A new nonlinear optical crystal 2-cyclooctylamino-5-nitropyridine (COANP) with point group symmetry mm2 has been grown by a temperature difference solution growth technique. Its linear and nonlinear optical properties have been investigated. The refractive indices na =1.702, nb =1.847, and nc =1.681 (λ=550 nm) and the…
A new series of hepta-coordinated mixed-ligand cyanonitrosyl complexes of vanadium (having {VNO}4 electron configuration1), formed by the interaction of potassium hexa-cyanonitrosylvanadate(I) monohydrate with some heterocyclic organic bases like 2, 3-, 2, 4-, 2, 6- and 3, 5- lutidines, 2, 3, 6- and 2, 4, 6- collidine…
The Fresnel coefficients describing reflection and refraction at an interface are derived in terms of the elements of the characteristic admittance matrix of an anisotropic medium. The cases considered include the general gyroelectromagnetic medium under normal incidence and the polar and longitudinal orientations und…
Abstract Small‐ and intermediate‐angle (0.006 < Q < 0.25 Å) neutron scattering experiments have been performed on polyethylene terephthalate (PET). Amorphous and semicrystalline samples with deuterated PET molecular weights of 24,200 and 40,500 were prepared. The average value of R /M determined in the small‐ang…
A light-pipe technique has been used to measure infrared spectra of U0 2 , U 3 O 8 , and UO 3 , in the range 2000 to 450 cm −1 . Comparison with transmission spectra found in the literature indicates that the technique is very suitable for characterization of actinide powders and will therefore be a useful tool for fu…
Abstract A method has been developed for the determination of the amount of acid gas produced during the thermal decomposition of PVC formulations. A method was required to support a program to reduce acid gas generation by retention of hydrogen chloride in the char phase. The traditional method (a modified Schoeniger…
The R2Fe14-xSixB compounds with R = Pr, Nd, or Er andx \leq 2crystallize in the Nd2Fe14B tetragonal structure. The Curie temperature increases by ∼ 17 K when one iron atom is substituted by silicon. In the high iron-concentration range the saturation magnetization decreases according to simple dilution behavior. For s…
Abstract Potassium release characteristics of vermiculite samples treated with K and various amounts of Rb, Cs, and Tl were determined using a miscible displacement technique. The amounts of K released, K release rates, and activation energy of K release ( E a ) were specifically examined. Increasing amounts of Rb, Cs…
This paper describes a recently developed standardized system for dull grading natural diamond, PDC, and TSP (Thermally Stable Polycrystalline diamond) bits, otherwise known as fixed cutter bits. The new system is consistent with the recently revised dull grading system for roller bits. It describes the condition of t…
Measurements have been made of the hysteresis of thermally and field-demagnetized sintered specimens of a Nd-Fe-B permanent magnet. Sets of minor hysteresis loops have been obtained by a gradual increase in the maximum applied field thus enabling the intrinsic coercivity and the remanence coercivity to be plotted as a…