Materials Literature
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In order to assist the microwave engineer in predicting the performance of partially magnetized devices, we have characterized the microwave permeability of partially magnetized materials. The real part of the tensor permeability elements, /spl mu/, /spl kappa/, and /spl mu//sub z/, depends primarily on the parameters…
The light-scattering spectra of magnetite (${\mathrm{Fe}}_{3}$${\mathrm{O}}_{4}$) have been studied as a function of temperature in an attempt to determine the role played by optical phonons in the Verwey transition. A group-theoretical analysis of the long-wavelength phonons is used to classify the normal modes in bo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSurface and colloid chemistry of claysS. Lee Swartzen-Allen and Egon MatijevicCite this: Chem. Rev. 1974, 74, 3, 385–400Publication Date (Print):June 1, 1974Publication History Published online1 May 2002Published inissue 1 June 1974https://pubs.acs.org/doi/10.1021/cr60289a00…
The role of silver and sulfadiazine in the mechanism of action of silver sulfadiazine on burn wound infections was investigated. Silver, but not sulfadiazine, was bound by bacteria. Sulfadiazine did not act as an antibacterial agent in low concentrations, but exhibited specific synergism in combination with subinhibit…
A conceptual model of the capillary hysteresis phenomenon is suggested. The advantage of this model is that all scanning curves are derived with the aid of simple functions from the main drying curve and the main wetting curves solely. Like the generalized approach of Enderby (1955) the present model takes into accoun…
In R-Fe compounds, the magnetic properties are mainly determined by the Fe-Fe interatomic distances and the number of Fe nearest neighbors. Below the ordering temperatures, the R2Fe17compounds are generally ferromagnetic or ferrimagnetic colinear. The compounds with rare earth ions of small atomic radii, Ce2Fe17, Tm2F…
A microscopic theory of the flow alignment in nematic liquid crystals is presented. The calculation is based on a thermodynamic sum rule derived earlier. The temperature dependence of the flow-alignment angle is obtained in terms of the nematic order parameter $S(T)$. The theory favors stable flow alignment, but the o…
Experimental evidence for a transition from localized to extended states in a two-dimensional band tail is obtained by measuring the conductivity in $n$- and $p$-type inversion layers in Si as a function of electron density and temperature (4.2 to 0.4\ifmmode^\circ\else\textdegree\fi{}K). A transition from metallic to…
Scanning electron microscope techniques show that Eocene opaline claystones (fuller's earth and buhrstone) of the Atlantic and Gulf Coastal Plain, deposits long considered volcanic in origin, are actually highly altered diatomites formed as transgressive facies in normal marine continental shelf environmnents. These f…
In iron-doped rutile (TiO 2 ) charge compensation is necessary since most of the iron substitutes as Fe 3+ for Ti 4+ . The well known EPR spectrum of iron-doped rutile is due to Fe 3+ substitutional ions in a perfect lattice. However, EPR measurements at 9.2 GHz revealed several additional EPR spectra which are explai…
The excited states of 24 Mg with excitation energies less than 14.0 MeV were studied by inelastic electron scattering in the momentum transfer range 0.4 to 1.14 fm -1 . Ground state transition probabilities and transition radii were deduced for 9 known levels with excitation less than 11 MeV and evidence was obtained…
The decay time of the cathodoluminescence emission from the H3 centre has been measured for diamonds containing nitrogen concentrations up to 0.15 atomic per cent, the nitrogen being predominantly in the A form. In five diamonds with low nitrogen concentrations, <or approximately=0.01 atomic per cent, the mean decay t…
Neutron diffraction experiments have been made to reveal the nature of the interstitial order-disorder transformation in the ZrO system using single crystals. The disordering transition of the alloy with O/Zr ⪅ 0.3 occurs below 450 °C, while in the composition O/Zr = 0.3 to 0.4 the disordering undergoes stepwise in s…
Using Poisson's method the demagnetization energy of magnetic dipole distributions is formulated and the equations are solved for the special case of doubly periodic distributions in infinite plates having arbitrary components of magnetization. As an example the energy of a simple bubble lattice with charged domain wa…
The recombination of oxygen in large excess of argon has been studied between 300 and 10 000 °K by trajectory calculations. Reasonable agreement between the computed results and the experimental rate data was obtained by assuming that the interaction between oxygen and argon atoms was 0.3 kcal/mol. The present calcula…
The dynamical critical phenomena associated with the structural phase transition of N${\mathrm{D}}_{4}$ Br (${T}_{c}=215$ \ifmmode^\circ\else\textdegree\fi{}K) have been studied by neutron-scattering techniques. The measurements of the low-energy part of neutron spectra of N${\mathrm{D}}_{4}$Br single crystals have be…
The steady-state photoresponse of the layer-structure crystal ${\mathrm{As}}_{2}$${\mathrm{S}}_{3}$ is reported as a function of wavelength, light intensity, and electric field strength, using aqueous salt solutions as transparent electrodes. The photocurrent spectrum follows the edge-absorption spectrum for photon en…
The photochemical isomerization of azobenzene in solution can be sensitized by dyes which have low-lying triplet states (rose Bengal, eosin Y, fluorescein, methylene blue) but cannot be inhibited by such compounds. The two triplet levels, T β c and T α c of the cis form are indistinguishable experimentally. On the oth…
The photochemical isomerization of azobenzene can be sensitized by aromatic compounds (chrysene, phenanthrene, naphthalene) or by carbonyls (benzil, biacetyl). Comparison of the photostationary states and the initial quantum yields of isomerization leads to the deduction of a mechanism for this sensitization. The trip…
An expression is obtained for the relaxation time for scattering of phonons by platelets of precipitated impurities of atomic masses and volume different from the host. For large-diameter platelets a closed expression was used in a model describing plateletlike nitrogen precipitates in type-$\mathrm{I}a$ diamonds. A f…