Materials Literature
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Abstract Ferruginous beidellites with Al:Fe atomic ratios up to 2.36 were obtained when solutions containing Al, Fe 2+ and H 4 SiO 4 were adjusted to pH 8.5 with Ca(OH) 2 and incubated at 95 °C in the presence of CaCO 3 as a pH buffer. Incubation took place under cyclic reducing and oxidizing conditions achieved by ad…
The physical structure of poly(methylphenyl) silane (PMPS) has been investigated using wide-angle x-ray scattering at various temperatures and optical polarizing microscopy. The results obtained by these techniques clearly show the existence of an ordered phase in PMPS. The crystallinity of our sample was estimated to…
We have investigated the orientational order in the nematic glass formed by the side group liquid crystal polymer poly[6-(4-methoxy-4‘-oxyazobenzene)hexyl methacrylate]- co -poly[methyl methacrylate] using ESR spectroscopy. In one experiment the order of the polymer backbone was investigated using a nitroxide attached…
Study of p -type porous silicon has been carried out by x-ray reflectometry for the first time. Its critical total-external-reflection angle and its reflection coefficient in the subcritical angle range are much smaller than for c -Si, which was grown by the Czochralski method. The critical angle decreases with increa…
Single crystals of the compounds SrZn(VO)(PO 4 ) 2 (I) and BaCd(VO)(PO 4 ) 2 (II) have been prepared by solid state reactions in evacuated quartz tubes. X-ray investigations confirmed orthorhombic symmetry, space group D 15 2h -Pbca, lattice constants a/b/c (I): 9.066(1)/9.012(1)/17.513(1) Å and (II); 8.838(4)/8.915(4…
The dispersion of longitudinal stress waves as they propagate in pressure bars distorts the shape of the puise, and so can be a limitation to the accuracy of high strain rate tests such as the compressive split Hopkinson pressure bar (SHPB). The method of dispersion correction described in this paper is based on a bar…
The temperature dependence of dc and ac conductivity in the vicinity of Tc3 = 112.5 K (on heating) for the MABB crystal was measured. For ac conductivity the frequencies between 20 Hz and 1 MHz were applied. The behaviour of conductivity was explained by means of power law [sgrave]ac = [sgrave]dc + Aωp, where ω is the…
Lattice dynamics calculations are presented for the synthetic cyclosilicate ${\mathrm{BaCuSi}}_{2}{\mathrm{O}}_{6},$ which contains isolated four-membered silicate rings. The results are analyzed in relation to published claims that vibrational modes of similar rings are responsible for the sharp ${D}_{1}$ ``defect li…
Triglycine sulfate-gelatin (TGS-gelatin) films were grown by evaporation of the water from a solution containing gelatin and TGS. The pyroelectric and dielectric properties of the films were highly dependent on their water content. Moist films had higher pyroelectric coefficients and lower coercive fields than dry fil…
Abstract The isolation at −78°C and characterization of the novel crystalline reactive porphinatomanganese(IV) complex Mn‐(TDCPP)(OCl) 2 ( 5 ) is described. 5 is compared with the porphinatomanganese(IV) complexes Mn(TDCPP)(C 6 H 5 IOCl) 2 (2), Mn(TDCPP)(C 6 F 5 10C1)CI ( 3 ) and Mn(TDCPP)(OCH 3 ) 2 , ( 4 ). The stoic…
Describes an investigation into the sensation of wetness and dampness by both subjective and objective measurements. When fabric has a high water content, the subject felt a strong feeling of stickiness. This stickiness was evaluated objectively by measurement of the friction between the wet fabric and artificial skin…
With an increase in the use of polyimides in aerospace applications, the degradation of polyimides caused in the space environment is receiving more attention. In this paper, a ground experiment in which polyimides were exposed to high-energy ions in the space plasma environment was carried out. The effects of oxygen…
Abstract Progress on the development of an in-situ nanoindentation specimen holder for the Kratos 1.5MeV HVEM located at the National Center for Electron Microscopy, Berkeley, CA, USA, is reported. There is currently considerable work being reported on the mechanical properties (i.e., hardness, delamination, wear, etc…
Abstract Experimental data on particulate‐filled polypropylene rupture are presented, with discussion and explanation of the regularities found. The systems studied are characterized by ductile properties of a semi‐crystalline matrix and a low level of interfacial interaction. Polypropylene as a host and aluminum hydr…
The electronic structure of Fe${}_{3}$B in orthorhombic $(o{\ensuremath{-}\mathrm{F}\mathrm{e}}_{3}$B) and body-centered tetragonal (bct-Fe${}_{3}$B) structures are calculated using the spin-polarized linear muffin-tin orbitals method. Based upon the calculated electronic structure, we present theoretical results on t…
The crystal structures of pure L-carvone [( R )-(−)-2-methyl-5-(1-methylethenyl)-2-cyclohexen-1-one, C 10 H 14 O] and the equimolar mixture DL-carvone ( RS ) have been determined by Patterson-search methods at low resolution from laboratory X-ray powder diffraction data (218 K). Crystal data: (L) a = 6.8576 (3), b = 6…
Compression tests have been performed on polycrystalline b.c.c. iron in order to study dynamic plasticity and evolution of microstructure. The paper describes the experimental setups and the results obtained at 295 K for strain rates 10-3s-1 ≤ dε/dt ≤ 104s-1 and plastic strains up to large values ε-0.8. Stress-strain…
Thermally induced packing correlations and apparent microphase spinodal boundaries are studied for conformationally asymmetric diblock copolymer melts using the “polymer reference interaction site model” (PRISM) theory. Microphase instabilities are deduced from predictions of the collective scattering intensities and…
A series of poly[methyl methacrylate (M)- b -styrene (S)- b -butadiene (B)- b -S- b -M], or MSBSM, pentablock copolymers have been successfully synthesized by sequential living anionic polymerization initiated with the diadduct of tert -butyllithium ( t -BuLi) onto m -diisopropenylbenzene ( m -DIB) in a cyclohexane/di…
A double-networked natural rubber (DNNR) was prepared by a “two-step crosslinking” method, in which the crosslinking was achieved while the natural rubber was in a stretched condition. The swelling behavior, tensile properties, creep, recovery, and permanent set were investigated. Generally, the observed mechanical pr…