Materials Literature
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The preparation and measurement of magnetic properties of cobalt-samarium permanent magnets prepared by liquid-phase sintering are discussed. Energy products in excess of 15×106 G Oe were observed. Long time exposure to air at 150°C did not degrade the samples.
The optical-phonon spectrum of ZnSi${\mathrm{P}}_{2}$ has been investigated by polarized Raman scattering at 6328 \AA{}. The results are compared with phonon modes in related tetrahedrally coordinated compounds and with a set of symmetry coordinates. The low-frequency dielectric constants are estimated from the Lyddan…
It has been suggested that two types of second sound, "drifting" and "driftless," are possible in dielectric crystals. The conditions for the existence of these two types of second sound are obtained, both from a heuristic analysis of the problem and from an exact solution of the complete linearized Boltzmann equation…
High-temperature powder x-ray diffraction photography and differential thermal analysis give 1643 K for the rhombohedral-to-cubic transition temperature of PrAl${\mathrm{O}}_{3}$; for NdAl${\mathrm{O}}_{3}$, this transition temperature is estimated to be 2020 K. The 800 K transition temperature of LaAl${\mathrm{O}}_{3…
Optical nonlinearities in crystals are for the first time analyzed from the rotational-invariance point of view. Several previous theoretical results are discussed on the basis of the decomposition of a tensor into irreducible parts. A proportionality between the spontaneous polarization and the vector parts of the no…
The observed degeneracy of mutually exclusive infrared- and Raman-active modes in MoS2 is traced by means of group theory to the weak van der Waals interaction between layers.Received 29 June 1970DOI:https://doi.org/10.1103/PhysRevLett.25.362©1970 American Physical Society
Measurements of the lifetime for positron annihilation in metals show a temperature dependence which has been ascribed to the trapping of positrons at vacancies. An explanation of this trapping process is presented in terms of an effective potential well, whose depth is the difference between the bottom of the positro…
Abstract The solubility behaviour of CuI was studied in KI‐acetone media in the concentration range of approximately 0.05 to 0.2 M. Within this range of iodide concentration, Cul 2 − was the only complex species found to occur in the liquid as well as in the solid phase. Conductometric studies also indicated the exist…
Potonie emend., is distally baculate and proximally smooth. Matonisporites Couper emened., has thicker corners, membraneous Y-rays and smooth exine. Callispora Dev emend., is characterized by having incipiently thickened angles and punctate exine. Boseisporites Dev emend., possesses two-layered exine, the outer layer…
The fatigue crack propagation behavior of Zircaloy-2 subjected to various environmental conditions was examined within the framework of linear elastic fracture mechanics. It was found that the fatigue crack growth rate increased with increasing levels of cold work, increasing temperature, and exposure to a water envir…
Abstract Release of potassium by extraction with solutions containing sodium tetraphenyl boron or by leaching with 0·1 N barium chloride seemed to be related to the nature of the mica layers in the interstratified minerals studied. The rate of potassium release was lower when the calculated Si/Al IV ratio of the mica…
Abstract Polyoxymethylene was successfully grafted with styrene, butadiene, and acrylonitrile by the mutual irradiation method in the monomer containing 18% of dimethyl formamide. The CO 2 and water vapor permeabilities and diffusivities were determined in the case of the butadiene‐ and acrylonitrile‐grafted products.…
The chemical and physical properties of cotton fabrics treated with formaldehyde in the presence of an acid catalyst (HCl) under aqueous (Form W) and essentially nonaqueous (Form D) conditions were investigated. Physical properties (tear strength, breaking strength, and crease recovery), functional group content (acid…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntermediates in the titanocene-promoted fixation-reduction of molecular nitrogenEugene E. Van Tamelen, Douglas A. Seeley, Stewart W. Schneller, H. Rudler, and W. CretneyCite this: J. Am. Chem. Soc. 1970, 92, 17, 5251–5253Publication Date (Print):August 1, 1970Publication Hi…
Abstract Synthesis of the first totally organic spiro polymer was accomplished by the reaction of 1,4‐cyclohexanedione and pentaerythritol in benzene plus a trace of p ‐toluenesulfonic acid to produce the polyspiroketal. The polymer did not melt, but began to decompose at 350°C. Although it was insoluble in most commo…
An investigation has been conducted to explore the possibility of using solid state Al2O3 in thermoluminescent dosimetry. The dosimeters were exposed to radiation energies ranging from 100 keV to 35 MeV. They displayed a constant response from 500 keV to 35 MeV comparable to LiF, and permitted accurate readings from 1…
Vanadium dioxide undergoes a crystallographic phase transformation at 68°C which is accompanied by a large and abrupt change in resistivity. Two devices, a two-terminal threshold switch and a four-terminal thermal relay, based on this effect are investigated theoretically and experimentally with regard to switching ap…
Abstract Poly(ethylene adipate), poly(ethylene suberate), and poly(ethylene sebacate) were synthesized by a modified ester interchange procedure. Polydispersity was reduced and low molecular weight material removed by fractional crystallization. Samples of 50–60% crystallinity were prepared by bulk crystallization and…
Tomoharu Ama, Jinsai Hidaka, Yoichi Shimura; Optical Resolution of a Heteropolymolybdate Anion, Bulletin of the Chemical Society of Japan, Volume 43, Issue
Abstract Rates of crystallization of copolyamides of nylons 66 and 6 have been measured by a photometric technique using a hot‐stage microscope. The copolymers all show some crystallinity, but the temperatures of crystallization are reduced as more comonomer is introduced. A close correlation between melting and cryst…