Materials Literature
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Summary The way pH changes in soil are propagated by movement of acids and bases is described. In acid soils the H 3 O + ‐H 2 O acid‐base pair is most important, while in alkaline soils the H 2 CO 3 ‐HCO 3 − pair is always dominant, its effect depending directly on the pressure of CO 2 . In neutral and slightly acid s…
The Raman scattering of the 93 cm−1 anomalous mode in NH4Cl above and below the λ-transition temperature (Tλ) was studied in detail. The peak and integrated intensities of this mode decrease rapidly to zero below Tλ. In contrast to the temperature behavior of a similar mode in NH4Br, the intensity data does not follow…
The shift in the position of a number of exciton peaks seen in the spectra of the layer type transition metal dichalcogenides has been measured in a hydrostatic pressure apparatus capable of reaching pressures up to 6 kilobars, in the temperature range 80°K to 295°K. For the Group 6 materials MoS2 and WSe2, the magnit…
The effects of porosity on the deformation characteristics of sintered polycrystalline UO 2 were determined at 500°, 1250°, and 1600°C at a strain rate of ∼0.1 h −1 . At 500°C, fracture was brittle and transgranular and initiated from the large pores present after fabrication. An increase in porosity from 5 to 16 vol%…
Abstract The relative photochemical reactivity of α-diketones, in particular, 9,10-phenanthraquinone, 1,2-naphthoquinone, acenaphthoquinone, benzil, 4,4′-dimethylbenzil, 2,4,6-trimethylbenzil, 2,5,2′,5′-tetramethylbenzil, 2,3,5,6-tetramethylbenzil, 2,4,6,2′,4′,6′-hexamethylbenzil, phenylglyoxal, 2,5-dimethylphenylglyo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation of porous layer open tubular columns by the dynamic methodJ. G. NikellyCite this: Anal. Chem. 1972, 44, 3, 623–625Publication Date (Print):March 1, 1972Publication History Published online1 May 2002Published inissue 1 March 1972https://pubs.acs.org/doi/10.1021/ac…
Abstract Intensity measurements of visible light and x‐rays and linewidth measurements of visible light scattered by one, two, and multicomponent systems for various equilibrium states in the neighborhood of the critical point are reviewed. By combining the angular dependence of the scattered intensity with that of th…
Abstract The proper use of lubricants and other additives in the compounding of PVC is hampered by lack of knowledge of their interactions with the polymer. Differential scanning calorimetry has been applied to measure the effect of ingredients on the glass transition temperature of PVC. An interaction parameter, base…
A theoretical treatment of nucleation-controlled polymer crystal growth is developed. A distinction is made between the end-surface energy of the crystal lamella and that of the nucleus for growth. The growth rate is related to the nucleation frequency using a thick-crystal treatment, and the lamellar thickness is vie…
Some allophanic soils in Japan, developed from deposits of volcanic ashes have aggregates, the sizes of which are mostly those of silt and sand, and which are very stable against the ordinary soil dispersion treatment such as decomposition of organic matter with hydrogen peroxide and addition of deflocculants to the s…
Summary Polarized spectra (2000 to 25000 Å) have been obtained for fifteen analysed trioctahedral micas covering a wide range of compositions, and including four phlogopites, nine biotites, and two lepidomelanes. Three main contributions to the absorption have been noted: charge transfer from oxygen to ferrous iron th…
Abstract The relation between biophysical properties of the skin of horticultural products and the rate of moisture loss under different ambient conditions is explained by a mathematical model. The numerical values of these properties can be determined by a simple experimental method. The effect of different air veloc…
SUMMARY The marine centric diatom Biddulphia levis produced uniflagellate fusiform male gametes completely within the parent cell frustule. These gametes lacked both a central pair of microtubules in the flagellar axoneme and chloroplasts but did contain a cone of microtubules which passed posteriorly from the base of…
Abstract Exposing one face of a catalyst pellet to a pulse of tracer gas and analyzing the response at the opposite and provides a dynamic method for measuring the effective diffusivity of porous catalysts. The first and second moments of the response peak are shown to be a function of only D e and the geometry of the…
The biosynthesis of vitamin B6 was studied in an Escherichia coli mutant, blocked between pyridoxol and pyridoxal. Specific incorporation of glycerol, pyruvate, serine, and glucose was shown by chemical degradation of labeled samples of pyridoxol isolated from the medium of cultures which had been incubated with vario…
The pair distribution function in amorphous deposited silicon monoxide has been measured at room temperature. The result is not in good agreement with expectations for a mixture of well-defined amorphous silicon and amorphous SiO2. Other possibilities, for which the average number of nearest-neighbor Si–O bonds per at…
Rate constants for collisional detachment of NO−, NO− + X → NO + X + e,have been measured from 193 to 506°K for X as He, Ne, H2, NO, CO, CO2, N2O, and NH3. The data fit Arrhenius plots kd=Ae−E/kT with both A and E showing large variations with X. From equilibrium constant considerations, electron attachment rates to N…
The spin density distributions in two alloys of iron and silicon (approximate compositions Fe3Si and Fe4Si) have been determined by polarized neutron diffraction. The observed data have been corrected for the effects of extinction and have been analysed by the standard Fourier method and also by expressing the density…
The structures of electroplated and vapor-deposited copper films have been studied by x-ray diffraction. While there was no evidence of stacking faults in any of these films, the electroplated films were characterized by presence of twins, large thickness-dependent microstrains, and small particle sizes. The vapor-dep…
Charge deposition on 2–25-μ m polyethylene terephthalate (PET), polyfluoroethylenepropylene (FEP), and polycarbonate (PC) foils by application of fields up to, and exceeding breakdown strength in the polymers is reported. The greatest negative or positive charge densities on PET foils metalized on one side are in exce…