Materials Literature
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Dynamic viscoelastic properties of composite systems composed of polybutadiene particles and polystyrene melts have been measured. The temperature dependence of a viscoelastic function is well expressed by the WLF equation. The rubbery plateau modulus is less dependent of the particle content and the molecular weight…
ABSTRACT Treatment of either of the stable anhydrous crystalline forms of or‐lactose with potassium methoxide in methanol at reflux does not result in the formation of β‐lactose, whereas the latter is formed from α‐lactose monohydrate or hygroscopic anhydrous α‐lactose under these conditions. We find that when β‐lacto…
Electron spin resonance has been used for the study of the radical in gamma-irradiated single crystals of 5'-UMP (sodium salt). Six types of radicals have been identified at room temperature. They are formed by addition of H atoms to C5, C6, 02 and 04, and by an OH addition to C5 of the uracil ring. Five of these radi…
Abstract Single crystals of Sr 2 Ti 6 O 13 were prepared by heating a mixture of SrO·Ti 2 O 3 ·2TiO 2 in a vacuum furnace to 1800 °C for 6 hours. X-ray investigations show monoclinic symmetry (a = 1525,0, b = 376,9, c = 916,4 pm; β = 99,15°, space group C 3 2h -C2/m). Sr 2 Ti 6 O 13 is isotypic with Ba 2 Ti 6 O 13 .
Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text K. D. Cummings and D. B. Tanner, "Far-infrared ordinary-ray optical constants of quartz," J. Opt. Soc. Am. 70, 123-126 (1980) Export Citation BibTex En…
A series of [2.4]cyclophanetetraenes and closely related compounds has been shown to undergo reversible two-electron reduction at a mercury electrode in dimethylformamide solution. The cyclophanes which contain a conjugated periphery of 4nπ-electrons, thus being formally antiaromatic hydrocarbons, form dianions of pro…
The rates of hydrogen desorption from liquid iron and several liquid binary iron alloys were measured by the carrier gas method using argon. The results obtained are summarized as follows.1. The rate of hydrogen desorption from liquid iron is governed by a first order reaction for hydrogen content in iron.2. The rate…
Abstract The clay and sand mineralogy of old (possibly 750 000 years) rhyolitic tephras of two sections located in south‐west and west Waikato, New Zealand, has been investigated by X‐ray diffraction, differential thermal analysis, infrared spectroscopy, transmission electron microscopy, and the polarising microscope.…
Abstract The crystal structures of two lithium nickel borides were determined by single crystal X-ray investigations. Li 3 Ni 20 B 6 (cubic, Fm3m, a = 1047.8 pm, Z = 4) crystallizes in the Cr 23 C 6 structure type with partly random distribution of lithium and nickel. The centers of the cubo-octahedra are statisticall…
SummaryThe introduction of quaternary pyridinium derivatives as brightening agents for the electrodeposition of zinc from alkaline electrolytes was one of the most significant recent advances in this field. This work describes the brightening effect of quaternary pyrindium derivatives, which have differences in struct…
By means of vacuum annealing in the range 525–775 K and under well controlled oxidative conditions the chemical composition of protective films of an AISI 316 stainless steel has been modified in order to increase the resistance to crevice corrosion. Independent of surface pretreatment the increase in critical potenti…
In order to analyse the bending rigidity of woven fabrics in any direction, the authors have theoretically derived a versatile equation (19) without neglecting twist effects of constituent yarns. Assuming that yarns are elastic and homogeneous and no interaction exists in yarns, the twist effects could be described as…
Abstract The contribution of exchangeable K to the K uptake by ryegrass in the field was studied on soils of the North Island whose dominant clay minerals were considered not to contain non‐exchangeable but plant available K. Six were derived from basalt or andesitic volcanic ash and 4 from sedimentary rock. On 8 site…
Abstract The effect of orientation on the structure and transport properties of high‐density polyethylene film has been studied. Microstructure was characterized using small‐angle light scattering, birefringence, and wide‐angle x‐ray scattering. Water vapor and oxygen transmission rates were determined as a function o…
A series of PDMS networks were prepared by endlinking reaction of α, ω-functional precursor polymers. The erosslinking reaction and the influence of incomplete reaction on formation of pendent chains are discussed. Equilibrium concentration and light spectroscopy measurements have demonstrated a decrease of the mesh s…
Treatment with mercury(II) acetate of metal complexes of porphyrins bearing peripherally unsubstituted positions gives the corresponding mercurated derivatives; using the palladium–olefin reaction, this observation is exploited in the synthesis of coproporphyrin III tetramethyl ester (2), harderoporphyrin trimethyl es…
The pyroelectric coefficient p of the mm2 phase of Fe-I and Cu-Cl boracite has been measured from 20 C upwards. The quasistatic Byer-Roundy technique applied to Fe-I boracite yielded p = 0. 01 x 10-8Ccm-2K-1 at 20°C, rising to 0. 1 x 10-8Ccm-2K-1 at 63°C; the extrapolated value for TC (72°C) is ∼ 1. 9 x 10-8Ccm-2K-1.…
The electron spin resonance of MnO42− has been studied at 4.2 K in single crystal K2SO4. The principal values of the g and A tensors are gx=1.9757, gy=1.9696, gz=1.9445, Ax=−21.0×10−4 cm−1, Ay=−25.5×10−4 cm−1, and Az=−147.6×10−4 cm−1. Az and gz make an angle of 7.8° and the only element of symmetry in the MnO42− tetra…
Les caractéristiques structurales et chimiques des aluminates et silicates hydratés contenant du nickel — caractéristiques qui, pour la plupart, ont été mises en lumière au cours de la dernière décade — sont passées en revue. La grande majorité de ces minéraux ressemblent aux silicates hydratés magnésiens avec substit…
Nickel was systematically substituted for cobalt in Waspaloy. M'echanical test results indicate that lower cobalt has little effect on tensile properties, but adversely affects creep rate and stress rupture life. Phase extraction studies found slight decreases in gamma prime volume fractions and increased M'23C6 carbi…