Materials Literature
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Abstract The crystal structure of isotactic poly(4‐methyl‐1‐pentene) was determined by x‐ray analysis. The unit cell is tetragonal, P 4 b 2, with α = 18.70 Å and c (fiber axis) = 13.68 Å; it contains four molecular chains each consisting of seven monomeric units in the fiber period. The molecular conformation is essen…
Laser flash photolysis has been used to characterise the triplet state of metal-free (H2Pc) and copper phthalocyanine (CuPc) in dilute (10–6 mol dm–3) solution in chloronaphthalene. This first observation of the triplet state of CuPc indicates that its lifetime is very short (∼35 ns), but the quantum efficiency of tri…
The paper describes the E, T phase diagram of lead zirconate in electric fields up to 1,400 kV/cm.
Grignard reactions on nickel meso-formyloctaethylporphyrin (1a) yield methyl and phenyl carbinols. The former is readily dehydrated to the meso-vinyl derivative, which by hydrogenation yields the meso-ethyl analogue, and by bromination and dehydrobromination affords the meso-ethynyl compound. The latter is readily oxi…
The circumstances under which steels exhibit intergranular fracture can be classified into four general categories: (1) owing to the presence of certain secondary phases at the grain boundaries; (2) owing to thermal treatments which cause impurity segregation to the grain boundaries without the precipitation of an obs…
Using derivative thermogravimetric analysis (DTG), polybutadiene is shown to degrade by two distinct weight loss events when heated dynamically. The volatile products of the first stage are almost exclusively depolymerization products (butadiene and vinylcyclohexene). The residue—cyclized and crosslinked polybutadiene…
The X-ray emission spectra (Mg-Kβ1,3, Mg-L2,3 M, and O-Kα), X-ray photoelectron spectra, and O-KLL Auger spectra from brucite, Mg[OH]2, are reported. The electronic structure of brucite is discussed using these spectra and a simple Hückel molecular-orbital model. The spectra indicate that the strongest interaction exi…
The kinetic mechanism of CVD deposition has been studied for ( i ) reaction at 675°–940°C for and , ( ii ) reaction at 400°–807°C for and , and ( iii ) reaction at 425°–578°C for and . In combination with the available literature data, the results of the present investigation have been interpreted to show atomic oxyge…
The surface tension γ has been measured for two cyanobiphenyls (5CB and 8CB) at temperatures near the nematic-isotropic transition temperature T c, using the Wilhelmy plate method. Reproducible results were obtained, but only by the exercise of considerable patience: for reasons that are discussed at the end of the pa…
Abstract The relative crystallinity of various moist potato starches were measured by X‐ray diffractometer. The diffraction patterns showed to become sharp with increasing of the amount of sorption moisture. Both areas of crystallinity portion were proportionally correlated with the amount of moisture. On the assumpti…
Earlier neutron-diffraction measurements [Willis (1964), Proc. Br. Ceram. Soc. 1, 9-19] on a single crystal of UO2.12 at 800°C showed that interstitial oxygen atoms enter the UO2 lattice at two kinds of site, which are displaced by about 1 Å along the (110) and (111) directions from the cubic-coordinated interstitial…
An explicit model of contact-charge exchange in polymers is proposed in which the steady-state exchanged charge resides in intrinsic molecular-ion states. The eigenvalue spectra of these states are inferred from metal/polymer contact-charge measurements using a theoretical formalism constructed for this purpose. This…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCryophotoclustering techniques for synthesizing very small, naked silver clusters Agn of known size (where n = 2-5). The molecular metal cluster-bulk metal particle interfaceGeoffrey A. Ozin and Helmut HuberCite this: Inorg. Chem. 1978, 17, 1, 155–163Publication Date (Print)…
From an analysis of the ac deconstriction of the hysteresis loop and microscopical observation of moving domain walls, it is concluded, that the ferroelectric domain stabilization in Mn-doped BaTiO3 crystals is due to bulk effects. Esr measurements have revealed that in reduced crystals Mn2+-V0 associates exist, havin…
The electric permittivities, refractive indices and densities of the homologous series of alkyl-cyano-biphenyls (CnH2n+1.φ.φ.CN) have been measured as a function of temperature in the nematic phases for n = 5 to 9, and in the smectic phases for n = 8 and 9. The results have been analysed in terms of the Maier and Meie…
Abstract Absorbed moisture was found to plasticize the type of cross‐linked epoxy resin system investigated, causing a lowering of the Ta and in turn affecting mechanical response, such as by shifting the relaxation moduli to shorter times. The phenomenon is described and quantified in terms of an existing free volume…
Recently compiled data for the first electron affinity and the first ionization potential are used to obtain values for an atomic electronegativity scale, based on the Mulliken relation. From this scale and a new compilation of work function data, a linear equation is obtained which includes a parameter for any given…
Extensive experiments were conducted on annealed copper under cyclic nonproportional strain histories. After cyclically stabilizing the material by uniaxial cycling, out-of-phase axial-shear strain cycling for the same effective strain range caused additional increases in stress amplitudes to restabilized levels. Foll…
We report the relative HH Raman spectra obtained from high-purity bulk samples of the primary glass formers SiO2, GeO2, B2O3, and P2O5. With 514.5-nm excitation, the peak Raman cross sections of these glasses have relative strengths of 1, 9.2, 4.7, and 5.7, respectively. The superior scattering strength of the latter…
Provides a systematic scientific basis for understanding and controlling the processing of powders and ceramic bodies. Applies a wide range of analytical tools for characterizing agglomerate features throughout the processing steps. Contains electron and optical micrographs and discusses the improvement of product rel…