Materials Literature
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A numerical method for the computation of electrostatic fields is described. The basis of the method is the use of fictitious line charges as particular solutions of Laplace's and Poisson's equations. Details are given of a digital computer program developed for field calculations by means of this method, and its appl…
Abstract Adjacent eu-latero-frontal cirri beat alternately and alternate cirri exhibit metachronous activity. Each cirrus consists of 22─26 pairs of cilia arranged in two parallel but alternating rows. Individual cilia leave the shaft of the cirrus at regular (0.6 μm) intervals on each side to extend across the interc…
The theory of thermal mixing between nuclear Zeeman interactions and electronic spin-spin interactions of impurities in dielectric solids, used to interpret the mixing between the Zeeman interactions of two nuclear spin species as the result of their separate coupling with the electronic spin-spin reservoir. The predi…
Abstract Ausgehend von Metallkomplexen 1a, 1f–1m des Octaatlylporphins [(OAP)MXY (M = Zn, Pd, Pt, Ga, In, Mn, Ti, V, Si)] wurden weitere (a,y‐Dimethyl‐a,y‐dihydrooctaathylporphinato)metallkomplexe 2f–2n [(OxPMe2)MXY (M = Pd, Pt, Ga, In, Mn, Ti, V, Si, Sn)] dargestellt und spektroskopisch charakterisiert. Die reduziere…
ZnO powder samples sized from 500 to 3 μm are annealed in reducing and oxidizing atmosphere, thus creating geometrical lattice defects which in the paramagnetic case can be detected with ESR. Predominantly oxygen vacancies, oxygen at interstitial sites, and the coupling of these two kinds of defects correlated to the…
Expansion due to illumination (photoexpansion) and contraction due to heat treatment (``thermal contraction'') of As–Se–(S)–Ge glass films have been observed utilizing the bimetal structures. This property is related to the reversible photodarkening effect of these chalcogenide glass films.
Multiconfiguration self-consistent field (MCSCF) wavefunctions are obtained for the ground and some low-lying valence excited states of the same symmetry for the diatomic systems CN and AlO. The spectroscopic constants of these states as well as their dipole moments as a function of the internuclear separation are als…
The optical properties of tetrathiofulvalene tetracyanoquinodimethan (TTF) (TCNQ) are reported in the visible and near infrared from room temperature to 4.2 K. The experimental results are analyzed in terms of simple Drude theory, with corrections made for anisotropic effects introduced by the anisotropic band structu…
The electrical resistivity and optical absorption of the layered dichalcogenides ${\mathrm{Ti}}_{x}{\mathrm{Ta}}_{1\ensuremath{-}x}{\mathrm{S}}_{2}$, ${\mathrm{Zr}}_{x}{\mathrm{Ta}}_{1\ensuremath{-}x}{\mathrm{S}}_{2}$, and ${\mathrm{Ti}}_{x}{\mathrm{Nb}}_{1\ensuremath{-}x}{\mathrm{Se}}_{2}$ ($0\ensuremath{\leqq}x\ensu…
The infrared spectrum of gaseous N2O4 was obtained under conditions which allowed study of both strongly and weakly absorbing features. These spectral features were assigned with the aid of vibration-rotation band shape theory. Weakly absorbing sequence bands were identified which contain torsional vibrations. The roc…
A new nematic material in which ε∥ exhibits a dielectric loss in the audio-frequency range is reported. At 25 °C Δ ε=(ε∥−ε⊥) reverses sign at 2.5 kHz and can be as positive as 6.2 at low frequencies and as negative as −2.2 at high frequencies; the activation energy for the loss is 0.91 eV. The availability of a dielec…
X-ray-diffraction radial-distribution, electron-spectroscopy-for-chemical-analysis (ESCA), crystallization, and differential-thermal-analysis (DTA) studies of glassy ${\mathrm{Cu}}_{x}{({\mathrm{As}}_{0.4}{\mathrm{Se}}_{0.6})}_{100\ensuremath{-}x}$ alloys, with 0 \ensuremath{\le} \ifmmode\times\else\texttimes\fi{} \en…
The driving force in electromigration is generally assumed to consist of a "direct force" due to the applied field and an "electron-wind" term due to momentum exchange with the current carriers. In the case of the "direct force" it is uncertain how effectively the charge is screened. In the case of the "electron wind"…
The bond-orbital model is reformulated taking explicit account of the large overlap of two hybrids in the same bond rather than absorbing it in a pseudopotential. This gives a correction to the cohesive energy but other changes are absorbed in the ${V}_{1}$, ${V}_{2}$, and ${V}_{3}$ for each material. These parameters…
The temperature dependence of the dc electrical conductivity of tetrathiofulvalinium tetracyanoquinodimethan (TTF)(TCNQ) measured along the crystallographic $a$, $b$, and ${c}^{*}$ axes and the corresponding anisotropies $\frac{{\ensuremath{\sigma}}_{\ensuremath{\parallel}}^{b}}{{\ensuremath{\sigma}}_{\ensuremath{\per…
The temperature dependence of the infrared reflectivity of rutile, Ti${\mathrm{O}}_{2}$, is reported in the range 275-900 ${\mathrm{cm}}_{\ensuremath{-}1}$ and from room temperature up to 1500 K, for both the ${A}_{2u}$- and ${E}_{u}$-type mode spectra. Reflectivity spectra are fitted with the aid of a four-parameter…
Elasticity theory is applied to nematic liquid crystals with particular boundary conditions. The calculus of variations is used to derive the torque equations, the solutions of which are found by relaxation methods on a digital computer. These solutions are used to draw pictures of the molecular arrangements and with…
The conductivity of single crystals of tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) was measured over the temperature range 40-300 K. The maximum low-temperature conductivity parallel to the $b$ axis ranged from 12-35 times the corresponding room-temperature value. The temperature dependence of the intrinsic…
Abstract X‐ray measurements as function of temperature were made from pure polyvinyl alcohol (PVA) and concentrated PVA‐solutions in water, glycerine, and glycol. The solutions form gels at adequate low temperatures. As the formation of a chemically bound network can be excluded gel formation must be related to physic…
The regeneration of cellulose from solutions in 85 percent phosphoric acid into glycerol at 170 degrees C resulted in its recovery wholly in the native or cellulose I lattice. Identification of the structure of the regenerated material is based on comparisons of its x-ray diffractogram and its Raman spectrum with thos…