Materials Literature
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A number of polytypes, existing over short intervals of structure, have been observed in enstatites. These include the27,36, and 54 A periodicities, in addition to the well known 9 A monoclinic enstatite (CLEN) and l8 A orthorhombic enstatite (OREN) polymorphs. The polytypes, as well as all other features described in…
Abstract New developments on photochromic polymers have been obtained with systems containing spirobenzopyran derivatives. The importance of the chemical incorporation of the photochrome within the polymer backbone is stressed, and the influence of matrix orientation on the rate of fading is shown. Well known fatigue…
Abstract The crystallinity of minerals in terms of crystallite size distribution and lattice perfection is quantified by means of statistical measures derived from X-ray line profiles (2 σ values). A low degree of crystallinity facilitates the non-stoichiometric incorporation of foreign elements in the crystal lattice…
This paper presents a classification scheme for tetrahedrally-coordinated oxides of formulae Li 3 XO 4 : X = P, As, V, Cr, Mn; AYO 2 : A = Li, Na; Y = Al, Ga, Fe, (not LiFeO 2 ) and A 2 BCO 4 : A = Li, Na; B = Be, Mg, Mn, Fe, Co, Zn, Cd; C = Si, Ge, (not all ABC combinations). These oxides are usually polymorphic and…
A previous calculation of the band structure of trigonal V2O3 and Ti2O3 by Nebenzahl and Weger is improved, taking a more rigorous treatment and including the effect of covalency. The agreement obtained with experimental results is good. It is found that the width of the 3d band is about 9 eV for V2O3 and 11 eV for Ti…
The superstructure of PPO/iPS blends, in which the iPS is partially crystallized from the glassy state by thermal treatment, is studied as a function of composition. A superstructure model, based on Hosemann’s treatment of a linear paracrystalline lattice, is used in order to calculate theoretical SAXS curves and fit…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDilute single-crystal electron paramagnetic resonance study of bis(cyclopentadienyl)vanadium pentasulfide, V(.eta.5-C5H5)2S5. Coup de grace to the Ballhausen-Dahl bonding model applied to M(.eta.5-C5H5)2L2-type complexesJeffrey L. Petersen and Lawrence F. DahlCite this: J. A…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron spin resonance studies of cation orientation in restricted water layers on phyllosilicate (smectite) surfacesMurray B. McBride, T. J. Pinnavala, and M. M. MortlandCite this: J. Phys. Chem. 1975, 79, 22, 2430–2435Publication Date (Print):October 1, 1975Publication Hi…
Chemical processes occurring in the vapor deposition of silicon from and in the etching of silicon by were studied by means of a mass spectrometer coupled to the CVD reactor. This setup was successfully used for the qualitative and quantitative analysis of the composition of the vapor phase in the Si‐Cl‐H system. Spec…
The incorporation of lattice dislocations into high-angle grain boundaries either with small radii of curvature or absorbing lattice defects is observed by the in situ heating of thin foils in a transmission electron microscope. At a given temperature, the rate of incorporation is higher than for equilibrium boundarie…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSmall anion binding to cycloamylose. Equilibrium constantsJ. F. Wojcik and R. P. RohrbachCite this: J. Phys. Chem. 1975, 79, 21, 2251–2253Publication Date (Print):October 1, 1975Publication History Published online1 May 2002Published inissue 1 October 1975https://pubs.acs.or…
The high intensity x-ray flux from the synchrotron radiation at the Stanford Synchroton Radiation Project has been used to study the extended x-ray absorption fine structure (EXAFS) of the iron-sulfur protein Peptococcus aerogenes rubredoxin. Absorption measurements were made from 7080 eV, which is below the K-edge of…
Interdiffusion in the Ti/Pd/Au thin-film system is measured using Rutherford backscattering. Interdiffusion rates of Pd/Au for temperatures between 200 and 490 °C have been correlated with the defect structure of the films using models of defect enhanced diffusion. Au diffusing in Pd has been analyzed by the Whipple m…
A comparison is presented of the results of intergranular (IG) corrosion testing by the standard method (ASTM A 262, Practice E) and by an electrochemical reactivation method. Five Cr-Ni and Cr-Ni-Mo steels containing 0.025 to 0.09% C were tested. Discrepancies between the classical and the electrochemical test are ac…
In order to obtain information concerning the effect of molecular weight on the molecular mobility involved in the relaxation processes associated with the nonequilibrium thermodynamic state of glassy polymers, enthalpy-relaxation studies have been undertaken on glassy atactic polystyrenes of various molecular weights…
Measurements of the pressure and temperature dependences of the soft-mode Raman spectra of potassium dihydrogen phosphate (KDP) in both the paraelectric (PE) and ferroelectric (FE) phases are reported. The soft-mode response is overdamped throughout the PE phase at atmospheric pressure, but can be made underdamped wit…
Abstract The dielectric functions ϵ | arid ϵ ⟂ of graphite were redetermined by electron energy loss spectroscopy. At 11 eV a strong maximum in Im (ϵ | )is obtained, which is in accordance with earlier electron energy loss experiments, but in disagreement with recent reflectance measurements. A detailed discussion of…
Abstract The luminescence lifetimes in K2Pt(CN)4·3H2O, BaPt(CN)4·4H2O and MgPt(CN)4·7H2O were measured at 1 atom. and higher hydrostatic pressures up to 7.2 kbar at room temperature. Two longer components lengthen anomalously by a factor of ∼ 30 with a decrease in the Pt–Pt distance from 3.50 to 3.16 Å.
Abstract Poly(1,3,4‐oxadiazole‐2,5‐diyl‐1,2‐ethendiyl) and poly(1,4‐phenylene‐1,3,4‐oxadiazole‐2,5 diyl‐1,2‐ethenediyl) have been prepared by condensation polymerization using fuming sulfuric acid and different quantities of terephthalic acid (T), fumaric acid (F), and hydrazine sulfate (HS). Homopolymers of F and T a…
SrSiO 3 occurs in two distinct modifications, shown by selected-area electron diffraction to be polytypes. The thermodynamically more stable form, SrSiO 3 (30 Å), has a geometrically near-rhombohedral unit cell, with a = 7.16, c = 30.36 Å on the pseudohexagonal axes, and is an analogue of SrGeO 3 . The other polytype,…