Materials Literature
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Experimental reflectance data for silicon are corrected for the presence of a surface oxide layer and analyzed using the Kramers-Kronig relation to yield a set of optical constants for oxide-free silicon. For etched silicon samples exposed to the atmosphere for ∼ 1 h, this layer is 12–15 Å thick and has the approximat…
Based on the wetting properties of a ‐Al 2 O 3 , and pyrolytic graphite by liquid metals, the critical surface energy for spreading was determined and compared with the surface energy of the ceramics. The surface energy γ‐ 8 (ergs/cm 2 ) of the (0001) surface of a ‐Al 2 O 3 is estimated to be 892–0.12 T (°C), that of…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrigin of some charge-transfer spectra. Oxo compounds of vanadium, molybdenum, tungsten, and niobium including heteropoly anions and heteropoly bluesHyunsoo So and Michael T. PopeCite this: Inorg. Chem. 1972, 11, 6, 1441–1443Publication Date (Print):June 1, 1972Publication H…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRedetermination of the structure of porphineBetty M. L. Chen and A. TulinskyCite this: J. Am. Chem. Soc. 1972, 94, 12, 4144–4151Publication Date (Print):June 1, 1972Publication History Published online1 May 2002Published inissue 1 June 1972https://pubs.acs.org/doi/10.1021/ja…
The ratio of the elastic constants of nematic liquid crystals is calculated using a simple inner field model. The result obtained is k11′: k22 : k33′: k24 : k13(2)=5:11:5:-9:-6. The first three constants, which are the constants for splay, twist, and bend, respectively, are found to be positive, in contrast with the r…
Abstract We present a theoretical treatment and give experimental observations of the deformation that occurs in a nematic liquid crystal when electric or magnetic fields are applied. We consider only normal deformations in the nematic material where fluid flow and other dynamic phenomena play no role. Three important…
Abstract Electronic energy band calculations for transition metal hydrides have provided a new theoretical understanding of these materials. The calculations show when the proton model has relevance and when the anion model is more appropriate, the essential feature being the structure of the hydride. The structure in…
Measurements have been made of the low-frequency admittance of contaminated Langmuir probes in a mercury-vapor plasma. It was found that the probe admittance components were frequency dependent and could be represented by an equivalent electrical circuit corresponding to a metal-insulator-plasma configuration. The fre…
This article presents the results of an experimental study of the void fraction at high pressure (80 to 140 kg/cm2) in two rectangular channels (5 × 0.2 and 5 × 0.28 cm) simulating a subchannel of a nuclear reactor plate-type fuel element. The method enabled the distribution of the local void fraction in a cross secti…
Abstract The decomposition of tert ‐butyl, cumyl, and polypropylene hydroperoxides catalyzed by SO 2 , H 2 SO 4 , dilauryl thiodipropionate, metal dithiolenes, and metal dithiocarbamates were studied. The principal reaction pathways leading to different products, which depend on the nature of the hydroperoxide and the…
Phosphorescence and excitation spectra have been measured in Fe3+-doped ordered and disordered LiAl5O8. A good fit with the Tanabe-Sugano diagram for a high spin d5 configuration with B=644 cm−1 and C=2960 cm−1 has been obtained. From the calculated 10 Dq value of 8000 cm−1 and a comparison with the excitation spectra…
It is shown that there is limited validitity to the doctrine that true interfacial separation, in an adhering system, is highly improbable. An analysis employing the Griffith-Irwin crack theory yields these results: The important parameters are, difference in elastic moduli, ΔE; differences in g, the energy dissipatio…
The thermal spike hypothesis for the radiation compaction of vitreous silica by energetic ions is developed in detail. The variation of the thermal constants with temperature and the variation of energy dissipation along the range are considered and are found to affect the problem little. When the hypothesis was first…
According to Bikerman, who attributes failure in adhints to a weak boundary layer, it is almost impossible and meaningless to correlate adhesive strength to surface-chemical properties of adhints. Though his assertion seems to be confirmed by the recent studies of Schonhorn and his coworkers on the methods of CASING a…
The transformations produced by quenching from the equilibrium β-phase region have been studied in a range of titanium alloys with 5·8-53 w/o tantalum. The martensitic phase is h.c.p. (α′) with up to 22 w/o Ta, and orthorhombic (α″) with 23-53 w/o Ta. In alloys with up to 32 w/o Ta, the product is finely twinned on {1…
Models for low-spin-high-spin transitions in transition-metal-ion compounds are presented. Within a molecular-field scheme, the transition between, and coexistence of, high-spin (Hund's-rule) and low-spin (crystal field) states are described. One- and two-sublattice-spin structures and the influence of magnetic intera…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal decomposition of complex metal hydridesJ. A. Dilts and E. C. AshbyCite this: Inorg. Chem. 1972, 11, 6, 1230–1236Publication Date (Print):June 1, 1972Publication History Published online1 May 2002Published inissue 1 June 1972https://pubs.acs.org/doi/10.1021/ic50112a01…
The presence of a conductive plane near a thin magnetic film perturbs the propagation of a surface magnetostatic wave. This paper treats the case of a dielectric layered structure, and an expression for the characteristic dispersion is derived. The dispersion is unique with respect to magnetostatic propagation in that…
The lattice parameters of BiFeO3 were determined with the Straumanis method. At 25–13±0.02 °C, the hexagonal parameters are ah = 5.5799±0.0003, and ch = 13.8670±0.0005 Å. The temperature dependence of the lattice parameters in the range 20–325 °C is given by the equations: ah = 5.5764 Å + 6.06 × 10−5t, and ch = 13.862…
A complete molecular-orbital energy-level diagram for Ti${\mathrm{O}}_{2}$ is empirically deduced from the combined $\mathrm{Ti}{L}_{\mathrm{III}}$, $\mathrm{Ti}K$, and $\mathrm{O}K$ x-ray emission and absorption band spectra. All of the occupied and vacant orbitals within 25 eV of ${E}_{F}$ are located on a relative…