Materials Literature
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Phase equilibrium studies have been carried out on the composition join NaAlSiO4-CaCO3-H2O with 25 wt per cent H2O at 1 kb pressure in the temperature range 600–960 °C. Liquid, in equilibrium with crystalline phases and a sodic, aqueous vapor phase persists across the join down to temperatures of about 600 °C. Fractio…
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The infrared and Raman spectra of anhydrous crystalline Li2CO3 and Na2CO3 were measured at 300 and at 80°K. Bands observed in the vibrational spectra of Li2CO3 were assigned according to the C2h factor group symmetry. The doublet structure observed for each of the internal modes in the spectra of Na2CO3 was interprete…
A simple physical model has been used to derive an approximate theory of the double extraction of uniformly generated electron-hole pairs from a photoconductor layer with noninjecting contacts. The theory predicts 4 regimes of current versus applied voltage behavior: (1) At low voltage, I∝V. (2) At higher voltage, a t…
Single crystals of the wide bandgap semiconductor stannic oxide, SnO2, have been grown and studied electrically. A chemical vapor deposition technique using chlorine transport, no inert carrier gases, and low pressure has been used to grow stannic oxide crystals of higher purity and with almost an order-of-magnitude h…
Refined structures of eight natural garnets [Cr-pyrope, almandine, spessartine, Mngrossular, grossular, uvarovite, goldmanite, and andradite] are compared with that of synthetic pyrope to determine the effects of the substituent cations on polyhedral interactions,bond lengths, and angles. The Si-O bonds in these garne…
A rectangular prism with edges in principal crystal directions is prepared with electrodes on the corners of one face. Voltage-current ratios for opposite pairs of electrodes permit calculation of components of the resistivity tensor. The method can use small samples, and is best suited to materials describable by two…
Nonohmic properties of ZnO ceramics with five additives of Bi 2 O 3 , CoO, MnO, Cr 2 O 3 , and Sb 2 O 3 are studied in relation to sintering temperature, additive content, and temperature dependence. The observation of electron photomicrographs and X-ray microanalysis proves a ceramic microstructure such that ZnO and…
An ion-beam deposition technique has been developed and was used to deposit thin films of insulating carbon on room-temperature substrates. It was established that the carbon films deposited using this technique are insulating and have the following characteristics similar to that of carbon in the diamond form: (1) tr…
Vitreous carbon, one of the most important materials based on graphite carbon, is outstanding in its high mechanical strength, resistance towards aggressive media, and imperviousness to gases. Because of these unique properties, there has been a rapid growth in the range of articles made of vitreous carbon and in the…
Vapour bubble collapse problems lacking spherical symmetry are solved here using a numerical method designed especially for these problems. Viscosity and compressibility in the liquid are neglected. Two specific cases of initially spherical bubbles collapsing near a plane solid wall were simulated: a bubble initially…
The olfactory nerve of the garfish, Lepisosteus, is about 1 millimeter in diameter and about 20 centimeters long, depending on the size of the fish; it is easily prepared by breaking off successive scored segments of the rostrum. It consists of a relatively homogeneous population of about 10(7) nonmyelineated nerve fi…
Abstract Der aus dem Holz der Edelkastanie ( Castanea sativa ) und der Eiche ( Quercus sesseliflora ) isolierte Gerbstoff Vescalin besitzt die Struktur 2a und ist damit anomer zu Castalin. Die Struktur wird bewiesen durch die saure Hydrolyse zu Flavogallonsäure ( 1a ) und D ‐Glucose sowie durch NMR‐ und Massenspektren…
Abstract In the transmission electron microscope, as shown in figure 1 (Nixon 1962), the electron gun at the top illuminates the specimen with the beam angle controlled by the condenser lens. The lenses below the specimen are used to magnify the image of the specimen which is viewed on the final screen at many thousan…
Abstract The various modes of specimen signal acquisition presently available on the scanning electron microscope permit both morphological and analytical studies to be carried out on the specimen. The advantage of the scanning electron microscope is that it provides an information-rich image at resolutions determined…
Abstract Unter verschiedenen Zustandsbedingungen wurde die Temperaturabhängigkeit der thermischen Schädigung von Nylon 6.6 und Nylon 6.10 vergleichend untersucht. Die erheblich größere thermische Unbeständigkeit von Nylon 6.6 läßt sich auf die Ringschlußtendenz des Adipinsäurebausteines zurückführen. In Gegenwart von…
Abstract A scanning microscope is described which is capable of a point resolution of 0.5 nm. We have demonstrated that it can produce the same kinds of micrographs as a conventional microscope. However, by using several detectors to produce signals corresponding to different groups of transmitted electrons we are abl…
An anomalously large magnetostriction has been found in ${\mathrm{Fe}}_{2}$Ti${\mathrm{O}}_{4}$. The magnetostriction constants ${\ensuremath{\lambda}}_{100}$ and ${\ensuremath{\lambda}}_{111}$ are (4.7 \ifmmode\pm\else\textpm\fi{} 0.4) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}3}$ and (1.3 \ifmmode\pm\e…
First measurements of double-photon elastic scattering performed on liquids with centrosymmetric molecules yield good agreement with statistical molecular theory of nonlinear light scattering. Studies of this new scattering are shown to allow determination of the third-order molecular polarizability as well as its ani…
The specific heat of YbFe${\mathrm{O}}_{3}$ in the range 1.5-15 K exhibits spin-reorientation and Schottky anomalies. The magnetic field dependence of the reorientation anomalies is consistent with phenomenological descriptions which predict that two second-order phase transitions occur in the reorientation process. T…