Materials Literature
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We propose a new interpretation of the 110\ifmmode^\circ\else\textdegree\fi{}K phase transition in SrTi${\mathrm{O}}_{3}$, in which the essential feature is a soft phonon at the corner of the cubic Brillouin zone. This interpretation is supported by new evidence from the temperature-dependent Raman spectrum as well as…
Given suitable correction factors, the use of pure oxides and binary oxide phases as standards would make electron microanalysis independent of chemical analyses and problems of sample inhomogeneity. Ziebold and Ogilvie (1964) have shown that the calibration curve in a binary metal alloy system can, within the varianc…
Abstract Rate constants of the thermal degradation of polymethylmethacrylate fractions have been measured over a range of temperatures, and the ARRHENIUS equations have been derived. There are two degradation reactions for this polymer; one “fast” reaction, which is chain‐end initiated, due to double‐bonded chain‐end…
Abstract Die rotierende Scheibenelektrode erweist sich als ausgezeichnetes Hilfsmittel bei der Untersuchung der Primärvorgänge bei der Elektrotauchlackierung. Das Modellbindemittel auf Acrylatbasis wird bei konstanter Stromdichte anodisch abgeschieden. Beim überschreiten einer Grenzdrehzahl n gr , die mit dem Quadrat…
In the present paper we compute the interband contribution to the imaginary part ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$ of the dielectric constant in diamond. This is done for several model band structures. In particular, we conclude that either the present first-principles calculations have to be modified…
The band structures of GaS and GaSe near the Fermi levels are derived in a semiempirical way. In view of the anisotropic structures, the π band structures are mainly studied. The valence band consists of a π band with the heavy effective masses. The conduction band at the center of the Brillouin zone has the light eff…
The atom positions in RuSe 2 , OsSe 2 , PtAs 2 , and α-NiAs 2 have been determined from X-ray powder diffraction data. In the pyrite-type compounds (Pa3), the metal atoms are in 4(a), the face-centered positions, and the nonmetal atoms in 8(c), with x = 0.381 ± 3 (RuSe 2 , a = 5.935 Å); x = 0.382 ± 4 (OsSe 2 , a = 5.9…
The pressure coefficients of the Curie temperature $\ensuremath{\theta}$ and the first-order transition temperature ${T}_{0}$ have been measured for two binary and three ternary alloys containing Fe and Rh. The coefficients are constant with pressure for all the alloys up to 25 kbars. The existence of a triple point i…
The cation distribution of MnxZn1−xFe2O4 (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8, 0.9, 1.0) has been determined by neutron diffraction. The fraction of the Mn2+ ions in the tetrahedral sites is correlated to the variation of the lattice parameter with x. It is concluded from the measurements that zinc ferrite is a completely…
A figure of merit is defined for an indexing of a given pattern as M20 = Q20/2\overline \epsilonN20. Here N20 is the number of different calculated Q values up to Q20, which is the Q value for the 20th observed and indexed line; is the average discrepancy in Q for these 20 lines. From a number of indexings which have…
Broad line nuclear magnetic resonance measurements were made over a wide temperature range from 77°K. to the melting point for polytetrahydrofuran and poly–1, 3–dioxolane. The NMR spectra showed two components at room temperature, broad and narrow, and these were attributed to crystalline and disordered regions, respe…
The use of high-power magnification with large numerical aperture (N.A.) objectives in determining the thickness of transparent films requires a thickness correction due to the effective angle of incidence not being perpendicular to the substrate. The effective angle of incidence is dependent upon both the numerical a…
The Born model of ionic solids has been used to make a complete determination of alkaline earth and chalcogenide ionic radii from solid state data alone. The additivity rule of interionic distances in the NaCl structure alkaline earth chalcogenides is used to relate the first- and second-neighbour contributions to the…
Measurements of the transmission spectra of thick silicon monoxide films are reported, and from these the absorption coefficient of silicon monoxide is calculated as a function of wavelength. The results obtained are compared with the predictions of a simple theoretical model.
Vom GaOOH, GaOOD und den entsprechenden partiell deuterierten Präparaten wurden die IR-Absorptionsspektren im Bereich von 10 000 bis 33 cm -1 aufgenommen und Banden den OH-Valenz- und OH-Librationsschwingungen und Schwingungen der GaO 6 -Oktaeder zugeordnet. Die Multiplizität der OH-Banden ist im wesentlichen auf eine…
Double-zeta functions 1 are very useful because of their relative simplicity connected with good accuracy as compared with the Hartree-Fock functions 2 . These two advantages make them an obvious choice even for semiempirical type of calculations. To test the doublezeta function we have calculated one-and two-center i…
The crystal structure of the rubidium salt of an octadecahydroeicosaborate(2-) photoisomer, Rb 2 B 20 H 18 , has been determined by X-ray diffraction vnth a single crystal specimen.The orthorhombic unit cell, space group Pn2 1 a, vnth ~ = 12.334 A, £ = 19.014A, £ = 7.260 A, contains four formula units.The structur.e w…
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It was possible to drive plastically blunted cleavage cracks through double cantilever beam specimens of impure MgO monocrystals in a series of small propagations. The forces required to propagate the cracks often defined a fairly constant apparent surface energy and provided an environment‐sensitive measure of toughn…
The crystal structure of ferrites including garnets and their methods of preparation are first reviewed. This is followed by an examination of microwave ferrite devices and their application to actual systems. Sufficient theoretical details as well as an extensive though not exhaustive list of references are included…