Materials Literature
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Evidence is given for the conversion of graphite to the diamond phase when it is subjected to strong, explosively generated shocks. The data lend support to a further conversion at still higher pressures to a new, higher density phase, presumably the closely-packed metallic liquid. (L.N.N.)
The method of multiple isomorphous replacement has been used to solve the structure of the protein myoglobin to a resolution of 2 A. EDSAC II has been programmed to calculate the phase angles, and the statistical treatment of errors proposed by Blow & Crick has been used throughout, leading not to the most probable el…
An X-ray method of crystallinity determination has been developed which takes into account the diffuse scattering due to thermal vibrations and lattice imperfections in the crystalline part of a substance. Application of the method to a series of polypropylene samples shows that this diffuse scattering is predominantl…
Abstract A detailed investigation has been made of twins in graphite crystals. The twins are regions misoriented from the crystal by a rotation of 20° 48' about a direction in the basal plane. The twin boundaries are shown to be simple tilt boundaries of a particular angle. As well as twins, bend planes of varying ang…
Abstract Infrared spectra have been recorded for cis and trans isomers of poly (1,4‐cyclohexylenedimethylene terephthalate) (PCHDT). Infrared dichroisms were determined and band assignments were made. From spectra of polymers in both the crystalline and amorphous phases it was determined that the crystalline bands for…
A laboratory investigation was made of various factors affecting the sulfide stress cracking resistance of a C-Mn-Mo grade of steel commonly used for producing API Standard 5A, Grade N-80 tubular products. It was found that the sensitivity to sulfide stress cracking of this steel in the normalized condition was increa…
Es wird eine Meßzelle beschrieben, mit der bei einem Druck von p ≦ 5·10 -9 Torr der elektrische Widerstand dünner, auf einem Glasträger aufgedampfter Alkalimetallschichten bei 90°K und 60°K in Abhängigkeit von der Schichtdicke gemessen wurde. An denselben Schichten wurde auch ihre Thermospannung gegen Platin als Bezug…
The changes in gamma‐ray induced optical absorption in phosphate glasses resulting from changes in composition, conditions during melting, and additions of small amounts of some oxides are discussed. A resolution of the induced spectra showed that the observed absorption is due to the superposition of three bands at 2…
Abstract The IR absorption spectra of various quartz crystals have been investigated; besides the vibrations due to the SiO 2 ‐lattice, there are bands in the 7000, 5000, 3000 and 900 cm −1 regions which are due to lattice imperfections. Variations in intensity of several powers of ten have been observed from one crys…
Abstract X‐ray diffraction methods were employed to determine a‐triclinic unit cell that describes the crystal lattice of poly ( trans ‐1,4‐cyclohexylenedimethylene terephthalate) (PCHDT). The crystal density was calculated as 1.265 g./cc., assuming one polymer repeat unit per unit cell. The fiber repeat period. 14.2…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSOLUBILITY OF CALCIUM CARBIDE IN FUSED SALT SYSTEMSWilliam A. Barber and Carol L. SloanCite this: J. Phys. Chem. 1961, 65, 11, 2026–2028Publication Date (Print):November 1, 1961Publication History Published online1 May 2002Published inissue 1 November 1961https://pubs.acs.or…
Measurements of magnetostriction on a single crystal of antiferro-magnetic nickel oxide were made in fields up to 21 kilo-oersteds. The order of magnitude of the magnetostriction is the same as that for ferromagnetic materials, viz about -20 × 10 -6 and a square law relation, with field, is obeyed up to several thousa…
Catalytic surface recombination of atomic oxygen is studied in a flow system by paramagnetic resonance absorption and a comparison is made with platinum wire detectors for the same conditions of flow. Recombination of oxygen atoms on a fuzed quartz surface is found to follow first-order kinetics with a surface recombi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal Degradation of O-1-Hexadecyl N-1-Naphthylcarbamates and Related CompoundsELIZABETH DYER and ROBERT E. READCite this: J. Org. Chem. 1961, 26, 11, 4388–4394Publication Date (Print):November 1, 1961Publication History Published online1 May 2002Published inissue 1 Novemb…
In NaNO 2 crystals, prepared both of the fusion method and the aqueous solution method, the D - E hysteresis loops were observed by the 50 c/s a c held and the dielectric constant along the ferroelectric b axis. ε b , was measured by the 100 kc/s a c voltage. The pyroelectric current was measured the usual galvanomete…
The absorption and fluorescence spectra of anhydrous DyCl3 were investigated and the levels up to 37 000 cm—1 above the ground state established. Conclusive evidence is presented that the levels below 15 000 cm—1 belong to the 6H and 6F multiplets. The Zeeman effects show considerable nonlinear interactions which foll…
The Boltzmann equation for electrons in many-valley semiconductors, with scattering by acoustical and optical lattice vibrations, is solved for high electric fields in the following two cases: (1) Intervalley-scattering is completely negligible. Then, in each particular valley, the distribution of the electrons over t…
The growth of crystals from the melt in oriented, crosslinked polyethylene was studied by x-ray diffraction and birefringence as a function of orientation. It was found that for samples elongated more than about 200%, the crystals grow with their c axes parallel to the stretching direction. At elongations less than 20…
In synthetischem GaSe wurden zwei polytype Modifikationen der Verbindung aufgefunden. Hexagonales β-GaSe besitzt eine Struktur des GaS-Typs; für rhomboedrisches γ-GaSe wurde die von SCHUBERT und Mitarbb. 6 bestimmte Struktur bestätigt. Die Beziehungen zwischen diesen beiden Modifikationen und einer weiteren Form, dem…
Abstract Über elektrische und optische Untersuchungen an Einkristallen von Chalkogeniden von Elementen der IV. Nebengruppe, insbesondere des Titans, wird berichtet. Es konnte u.a. der Leitungstypus dieser Verbindungen bestimmt werden. Mit Ausnahme des metallisch leitenden TiS handelt es sich bei den hier besprochenen…