Materials Literature
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Approximate wave functions for the hydrogen molecule ground state previously available in the literature are analyzed quantitatively into approximate natural spin orbital functions with particular attention to the corresponding occupation numbers. The analysis demonstrates the very great similarity of all such trial w…
The conditions for preparing evaporated Al films of highest reflectance for mirrors and gratings to be used in the vacuum ultraviolet are summarized, and an account is given of aging studies. The preparation of bloom-free, one-micron thick coatings for grating blanks is described, and the effect of thin overcoatings o…
The general treatment developed in previous papers is applied to the case where the aqueous solution of polyvinyl alcohol is irradiated by gamma rays and the results are compared with Danno's measurements. The behaviours of irradiated aqueous solution of polyvinyl alcohol before and after gelation are well explained b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTheory of Agar Diffusion Methods for BioassayR. K. FinnCite this: Anal. Chem. 1959, 31, 6, 975–977Publication Date (Print):June 1, 1959Publication History Published online1 May 2002Published inissue 1 June 1959https://pubs.acs.org/doi/10.1021/ac60150a040https://doi.org/10.10…
Saturation of thc microwave electron paramagnetic resonance of impurities in various materials produces enhanced and reversed nuclear polarization throughout the material. This effect was investigated and is discussed in some detail for LiF single crystals. Results for other materials at microwave frequencies between…
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
The problem of obtaining a photonuclear cross section from a yield curve measured with a bremsstrahlung beam is discussed. This paper constitutes part of a larger report on the same subject containing numbers enabling cross-section analysis in the energy range 2 Mev to 1 Bev.
The kinetic theory for the rate of stress-assisted precipitation on dislocations is re-examined in order to extend the work of Cottrell and Bilby. Two approximate expressions are used for the elastic interaction between a solute atom and edge and screw dislocations: V=−A sinθ/r and V=−B/r, respectively. The resulting…
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Thermal‐expansion data on Al 2 O 3 , BeO, MgO, B 4 C, SiC, and TiC were obtained to the temperatures where permanent deformation begins, due to sintering or other causes. The thermal expansion for these materials was found to be approximately linear over the measured temperature range. But as a linear extrapolation to…
The anisotropy and magnetostriction of single crystals of several ferromagnetic materials have been determined experimentally. The materials include the metals iron and nickel, binary alloys of nickel iron, silicon iron, aluminum iron, cobalt nickel, and cobalt iron, ternary alloys of molybdenum nickel iron, nickel co…
The solubility of carbon in silicon has been measured over the temperature range 1560 to 2900°C. The enthalpy of solution is 59±3 kcal/mole. A phase diagram for the system Si–C is presented, embodying these solubility data as well as the results of other high-temperature experiments with silicon carbide. It is found t…
Abstract The infrared spectra of oriented films of valonia cellulose and of ramie and bacterial cellulose crystallites have been observed in the 3 μ region. Polarization properties of the bands have also been determined. The differences between the polarized spectra of bacterial and ramie crystallites in this region a…
A new type of antiferromagnetic spin arrangement, which is theoretically possible in the rutile type crystal and seems to be realized in polianite, MnO 2 , is proposed. This spin arrangement, which will be named the screw-type structure , consists of spins screwing along the four-fold crystalline axis. The stability r…
The effect of combined hydrostatic pressure, P, and of uniaxial tension, [sgrave], on the rupture time of polycrystalline copper wire in the temperature range 400° to 500°c has been determined. All the specimens broke by intergranular fracture, due to the growth of voids along grain boundaries. Preliminary experiments…
The ground-state wave function of the antimony, phosphorus, and arsenic impurities in silicon has been investigated by means of the electron nuclear double resonance (ENDOR) method. By this method the hyperfine interactions of the donor electron with the ${\mathrm{Si}}^{29}$ nuclei situated at different lattice sites…
After a critical review of the present state of knowledge about thermoluminescence, which is shown to be rather unsatisfactory, the present paper considers in detail thermoluminescence arising from thermal bleaching of $F$-centers in irradiated alkali halides. A model is proposed, which leads to second-order kinetics…