Materials Literature
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Abstract The dielectric properties and the d. c. conductivity of poly(vinyl chloride), poly(vinyl acetate), polychlorotrifluoroethylene, and poly(ethylene terephthalate) were measured at temperatures above and below the glass transition temperature and at various pressures up to 3000 atm. The α relaxation associated w…
Single crystals of MnSb with various Mn compositions in ε phase were prepared successfully with Bridgeman method. Magnetization and torque measurements were made on these crystals in temperatures ranging from 4.2°K to 800°K. The temperature dependence of saturation magnetization on the sample with 48.2 at. % Mn was in…
A new electro-optic effect based on the disruptive effects of ion transport through certain classes of nematic liquid crystals is presented. The initially transparent liquid scatters light strongly (appears white) when subjected to fields of 5 × 103 V/cm. Reflective contrast ratios of better than 20:1 with efficiencie…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTemperature dependence of photoisomerization. V. Effect of substituents on the photoisomerization of stilbenes and azobenzenesDina Gegiou, K. A. Muszkat, and Ernst FischerCite this: J. Am. Chem. Soc. 1968, 90, 15, 3907–3918Publication Date (Print):July 1, 1968Publication His…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structures of hexacyanometalate complexesJohn J. Alexander and Harry B. GrayCite this: J. Am. Chem. Soc. 1968, 90, 16, 4260–4271Publication Date (Print):July 1, 1968Publication History Published online1 May 2002Published inissue 1 July 1968https://pubs.acs.org/doi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetic analysis of thermogravimetric dataJ. ZsakoCite this: J. Phys. Chem. 1968, 72, 7, 2406–2411Publication Date (Print):July 1, 1968Publication History Published online1 May 2002Published inissue 1 July 1968https://pubs.acs.org/doi/10.1021/j100853a022https://doi.org/10.10…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular orbital theory of the electronic structure of organic compounds. II. Spin densities in paramagnetic speciesJ. A. Pople, David L. Beveridge, and Paul A. DoboshCite this: J. Am. Chem. Soc. 1968, 90, 16, 4201–4209Publication Date (Print):July 1, 1968Publication Histor…
Abstract Considerable progress has been made in the past 20 years in the synthesis, characterization and fabrication of plastics. Previous SPE Award winners, such as Mark, Natta, and Marvel dealt largely with synthesis; Flory with characterization; Alfrey and Du Bois with fabrication. One of the still unsolved problem…
A survey is presented of the structural aspect of polymer crystals. It deals primarily with crystals grown from solutions but includes some features of crystallization from the melt. Special emphasis is placed on those aspects which are specific to polymers. It is attempted to place the subject in its historical persp…
We propose a new interpretation of the 110\ifmmode^\circ\else\textdegree\fi{}K phase transition in SrTi${\mathrm{O}}_{3}$, in which the essential feature is a soft phonon at the corner of the cubic Brillouin zone. This interpretation is supported by new evidence from the temperature-dependent Raman spectrum as well as…
Given suitable correction factors, the use of pure oxides and binary oxide phases as standards would make electron microanalysis independent of chemical analyses and problems of sample inhomogeneity. Ziebold and Ogilvie (1964) have shown that the calibration curve in a binary metal alloy system can, within the varianc…
Abstract Rate constants of the thermal degradation of polymethylmethacrylate fractions have been measured over a range of temperatures, and the ARRHENIUS equations have been derived. There are two degradation reactions for this polymer; one “fast” reaction, which is chain‐end initiated, due to double‐bonded chain‐end…
Abstract Die rotierende Scheibenelektrode erweist sich als ausgezeichnetes Hilfsmittel bei der Untersuchung der Primärvorgänge bei der Elektrotauchlackierung. Das Modellbindemittel auf Acrylatbasis wird bei konstanter Stromdichte anodisch abgeschieden. Beim überschreiten einer Grenzdrehzahl n gr , die mit dem Quadrat…
In the present paper we compute the interband contribution to the imaginary part ${\ensuremath{\epsilon}}_{2}(\ensuremath{\omega})$ of the dielectric constant in diamond. This is done for several model band structures. In particular, we conclude that either the present first-principles calculations have to be modified…
The band structures of GaS and GaSe near the Fermi levels are derived in a semiempirical way. In view of the anisotropic structures, the π band structures are mainly studied. The valence band consists of a π band with the heavy effective masses. The conduction band at the center of the Brillouin zone has the light eff…
The atom positions in RuSe 2 , OsSe 2 , PtAs 2 , and α-NiAs 2 have been determined from X-ray powder diffraction data. In the pyrite-type compounds (Pa3), the metal atoms are in 4(a), the face-centered positions, and the nonmetal atoms in 8(c), with x = 0.381 ± 3 (RuSe 2 , a = 5.935 Å); x = 0.382 ± 4 (OsSe 2 , a = 5.9…
The pressure coefficients of the Curie temperature $\ensuremath{\theta}$ and the first-order transition temperature ${T}_{0}$ have been measured for two binary and three ternary alloys containing Fe and Rh. The coefficients are constant with pressure for all the alloys up to 25 kbars. The existence of a triple point i…
The cation distribution of MnxZn1−xFe2O4 (x = 0, 0.1, 0.2, 0.4, 0.6, 0.8, 0.9, 1.0) has been determined by neutron diffraction. The fraction of the Mn2+ ions in the tetrahedral sites is correlated to the variation of the lattice parameter with x. It is concluded from the measurements that zinc ferrite is a completely…
A figure of merit is defined for an indexing of a given pattern as M20 = Q20/2\overline \epsilonN20. Here N20 is the number of different calculated Q values up to Q20, which is the Q value for the 20th observed and indexed line; is the average discrepancy in Q for these 20 lines. From a number of indexings which have…
Broad line nuclear magnetic resonance measurements were made over a wide temperature range from 77°K. to the melting point for polytetrahydrofuran and poly–1, 3–dioxolane. The NMR spectra showed two components at room temperature, broad and narrow, and these were attributed to crystalline and disordered regions, respe…