Materials Literature
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The modified potassium dihydrogen phosphate (KDP) model of a two-dimensional ferroelectric with the inclusion of an arbitrary electric field $\mathcal{E}$ is considered. The nature of the phase transition is unaffected by the inclusion of an external field, whereas the transition temperature depends on $\mathcal{E}$ w…
Polarized Raman spectra of tetragonal BaTi${\mathrm{O}}_{3}$ have been obtained at room temperature with He-Ne laser excitation. Using several different crystallographic directions for the phonon wave vector q, most of the vibrational modes for q\ensuremath{\sim}0 have been classified using Raman data alone. Three pai…
The existence of two forms of cobaltous oxide, CoO(I) and CoO(II), has been established by M\"ossbauer, x-ray, and chemical techniques. CoO(I) has the NaCl structure as determined by a well-resolved powder x-ray pattern. Its density is measured to be 6.4 g/${\mathrm{cm}}^{3}$ from both x-ray and direct macroscopic exp…
In connection with the Cochran theory of ferroelectricity, the thermal conductivity has been investigated in SrTi${\mathrm{O}}_{3}$ between 5 and 300\ifmmode^\circ\else\textdegree\fi{}K and in KTa${\mathrm{O}}_{3}$ between 2.5 and 300\ifmmode^\circ\else\textdegree\fi{}K. For temperatures above its maximum value, the c…
The complex dielectric constant of Rochelle salt has been measured at frequencies from 2.5 to 13 GHz, and at 155 MHz. The measurements were made in a temperature range from -50 to 45\ifmmode^\circ\else\textdegree\fi{}C which includes the ferroelectric region and significant parts of both paraelectric regions. Measurem…
The consequences of a simple type of exchange interaction between free charge carriers in a broad energy band and localized magnetic moments are discussed. The interaction causes a splitting of the energy bands into bands for the two spin directions. It also leads to spin-disorder scattering of the charge carriers. Th…
The change in the free energy that occurs when electric and magnetic fields are simultaneously applied to a magnetoelectric medium is calculated. It is shown that a quadratic form related to this change in the free energy is positive definite, from which it follows that all elements of the magnetoelectric-susceptibili…
The electron-spin-echo phase memory ${T}_{M}$ has been studied both experimentally and theoretically for the specific case in which it is limited by the lattice relaxation processes occurring in the sample. The relevant mechanism is as follows. Lattice relaxation of any spins, whether or not they belong to the species…
Received 8 November 1968DOI:https://doi.org/10.1103/PhysRevLett.20.798©1968 American Physical Society
Two polymorphic forms of aspirin were characterized; the rates of dissolution of single crystals and of tablets were studied. One forms dissolves 50 percent faster than the other.
Hypervelocity impact effect on structural honeycomb spacecraft wall configurations, stressing design and wall thickness parameters
X-ray and electron spin resonance studies are reported of the paramagnetic material [(CH 3 ) 4 N] 2 Cu[S 2 C 2 (CN) 2 ] 2 in single-crystal form, and also of this compound diluted in its diamagnetic nickel analogue. This mixed crystal is triclinic, and the copper ion has axial magnetic symmetry, with the Hamiltonian p…
Abstract It is reported that mats formed by the sedimentation of single crystals of methyl‐ and ethyl‐branched polyethylene exhibit strength and ductility comparable with that of melt‐crystallized films. In fact, in the case of methyl‐branched polymers, extensions of up to 50× were obtained on cold drawing. Observatio…
Abstract Die bei 709°C durch peritektische Reaktion gebildete Hochtemperaturphase hat die Zusammensetzung Cu 9,5 As 4 , sie kristallisiert kubisch mit einer Formeleinheit im Elementarkörper. Bei langsamem Abkühlen zerfällt die Hochtemperaturphase peritektoid zwischen 360 und 340°C in β‐Cu 3 As und As. Durch Abschrecke…
Abstract Phase relationships of isotactic polypropylene in various organic diluents were investigated. The diluents used were aliphatic alcohols, alkyl phenols, aryl phenols, diphenyl derivatives, alkyl aryl ethers, esters, and others. Among the diluents examined, n ‐butyl alcohol, p‐tert ‐butyl phenol, p‐tert ‐amyl p…
An experimental study of the TiCo/TiCo+Ti2Co and TiCo/TiCo+TiCo2 phase boundaries has been carried out using high-temperature x-ray diffractometry. The results, together with the result of an approximate mp determination, have been used to delineate the TiCo phase field. By combining this information with the results…
Abstract An idealized polymer model is used to examine the magnitude of the catastrophic tensile breaking energy and stress in terms of primary and secondary bonding forces. Computed strengths for primary and secondary bonding are respectively 8000 and 500 times larger than observed values of a common thermoplastic. F…
The various discharge phenomena caused by contamination of insulator surfaces were investigated by means of slow and fast oscillographic recordings of the discharge current. It was found that the surface discharges have distinct stages of development. The visual manifestations were recorded simultaneously with the cur…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron impact and thermal fragmentation of biphenyleneLester Friedman and Donald F. LindowCite this: J. Am. Chem. Soc. 1968, 90, 9, 2324–2328Publication Date (Print):April 1, 1968Publication History Published online1 May 2002Published inissue 1 April 1968https://pubs.acs.o…
In any attempt to interpret broadened X-ray diffraction peaks in terms of imperfections in polycrystalline specimens, particular attention should be paid to experimental technique and the method of collecting data. The experimental conditions should be arranged to give maximum intensity in as short a time as possible,…