Materials Literature
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The chemical nature of the electron-dense areas appearing on the organic matrix during the early stage of shell regeneration in Helix has been ascertained. These areas of 500–5000 Å are made up mainly of acid mucopolysaccharides as detected by thorium staining. When treated by 1% phosphotungstic acid (PTA) for a short…
Reactions between corundum and cristobalite in mixed powders and at interfaces between sintered pellets at 1500°C and in various forms of reaction couples at 1550°C were studied by quantitative X‐ray diffraction, electron microprobe analysis, and optical microscopy. The results indicate that a noncrystalline product i…
Crystalline gallium mycobactin P and chromic mycobactin P have been prepared. The chromic compound, unlike other metallic complexes of mycobactin P, does not detectably exchange its metal with ferric iron; it competitively antagonizes the growth-promoting action of mycobactin P towards Mycobacterium johnei. Mycobactin…
1. Mg(2+) or Mn(2+) starvation causes suspensions of Bacillus subtilis strain W 23 to accumulate bound amino sugars that are soluble in trichloroacetic acid. 2. The presence of chloramphenicol or puromycin produces higher intracellular concentrations of amino sugars during Mg(2+) starvation, but neither compound can s…
Abstract An investigation is carried out to determine the onset of convection of a horizontal layer of liquid subject to temperature of T 1 and T 2 at lower and upper surfaces, respectively. The liquid is assumed to possess a maximum density value at T max with T max between T 1 and T 2 . The temperature‐density relat…
Microstructural changes preceding the formation of the equilibrium (α-Al2O3) phase in non-stoichiometric magnesium-aluminium spinel have been examined by electron microscopy. Two intermediate phases have been identified which nucleate on paired partial dislocations in the spinel matrix. Both phases have monoclinic sym…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAqueous boric acid-borate-mannitol equilibriumsJohn. Knoeck and John Keenan. TaylorCite this: Anal. Chem. 1969, 41, 13, 1730–1734Publication Date (Print):November 1, 1969Publication History Published online1 May 2002Published inissue 1 November 1969https://pubs.acs.org/doi/1…
The spectra and photochemistry of the different isomers of some anils of salicylaldehyde and hydroxynaphthaldehyde were investigated over a range of solvents and temperatures. By running flash experiments in fluid solutions it was shown that both intramolecularly H-bonded enol (E) and cis-keto (QA) tautomers yield the…
Some physical properties okf phosphate glasses con‐taining up to about 26 mol% Fe 2 O 2 were studied. Pronounced changes in properties were observed at compositions containingabout 6, 10, and 13 mol% Fe 2 O 3 . The X‐ray diffraction spectra of devitrified (heat‐treated) samples showed new compounds near these composit…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular structure of the decamolybdodicobaltate(III) ionHoward T. Evans Jr. and John S. ShowellCite this: J. Am. Chem. Soc. 1969, 91, 24, 6881–6882Publication Date (Print):November 1, 1969Publication History Published online1 May 2002Published inissue 1 November 1969https:…
Abstract A new monoclinic phase of cerium orthovanadate, CeVO4(H), was found during the course of oxidation of pseudo-perovskite CeVO3 below 400°C. It has been confirmed to crystallize in the huttonite-type structure (C2h5−P21⁄n), that of LaVO4. The lattice parameters were determined to be: a 0=6.98Å, b0=7.22Å, c0=6.7…
The normal and the abnormal absorption coefficients of X-rays due to the Compton scattering and the thermal diffuse scattering (TDS) are calculated numerically by taking into account the temperature effect. It is found that effects of both scatterings are comparable for light atoms such as Al and Si, and that the effe…
The existing measurements and theories of the low-temperature thermal properties, heat capacity, and thermal conductivity of polymers are reviewed with particular attention paid to the differences between partly crystalline and amorphous polymers. The most striking feature of the low-temperature heat capacity of polym…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUnusual metalloporphyrins. IV. Novel methods for metal insertion into porphyrinsMinoru Tsutsui, Rance A. Velapoldi, Keinosuke Suzuki, Frederick Vohwinkel, Mitsuo Ichikawa, and Takashi KoyanoCite this: J. Am. Chem. Soc. 1969, 91, 23, 6262–6266Publication Date (Print):November…
The relaxation behavior of polymers at low temperatures, as studied by dynamic mechanical, dielectric, and nuclear magnetic resonance methods, is reviewed. Modulus values at 4 and 77°K are tabulated for a variety of both crystalline and amorphous polymers and are compared to room temperature values as well as to theor…
Abstract The wetting properties of a series of polyacrylates containing the fluoroalkyl group \documentclass{article}\pagestyle{empty}\begin{document}$ [\rlap{--} ({\rm CF}_{\rm 2} \rlap{--} )_2 {\rm CF}_2 {\rm H}\ $\end{document} have been studied. Where n is 7 and 9, the polyacrylates are highly crystalline at room…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDielectric Dispersion in Branched Polypropylene OxidesW. H. Stockmayer and J. J. BurkeCite this: Macromolecules 1969, 2, 6, 647–650Publication Date (Print):November 1, 1969Publication History Published online1 May 2002Published inissue 1 November 1969https://pubs.acs.org/doi…
Absolute differential cross sections of electrons elastically scattered by Hg have been measured at 500, 400, and 300 eV. We find that over this energy range, for angles between 2.5° and 20°, the measured cross sections can be accurately described using the Born approximation with a long-range effective potential of t…
The far-infrared spectra of thin films of ammonium iodide were recorded from − 170°C to room temperature. The results varied with the temperature at which the films were formed thus making the interpretation of the spectra difficult. Laser excited Raman spectra of polycrystalline NH4I, ND4I, NH4Br, and ND4Br were also…
On étudie la structure de gouttelettes de cristal liquide nématique en émulsion dans un liquide isotrope. Suivant la tension superficielle, les molécules sont normales ou tangentes à la surface. Les configurations stables sont alors soit en étoile, soit bipolaires. On calcule l'énergie de telles configurations en cham…