Materials Literature
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The mechanism of the interfibrillar and intrafibrillar swelling of cotton has been investigated by infrared and x-ray methods. Emphasis is on swelling in caustic soda, but other reagents are also considered. The presence of intrafibrillar swelling can be shown by detection of intermediate complex formation, while the…
A brief survey is given of recent applications of electrode potential measurements for the study of the corrosion of metals and alloys in the presence of aqueous solutions, molten salts and gaseous atmospheres. Particularly considered are: (1) cathodic and anodic protection of passivable metals and alloys in the prese…
Mixtures of cholesteryl iodide and cholesteryl bromide with cholesteryl nonanoafce were exposed to UV radiation and the resultant color shifts were measured as a function of exposure and composition. The formation of images by this process will be described, and the presiding mechanism will be briefly discussed.
CdO films were prepared by a D–C reactive sputtering method with various sputtering voltages. The characters of the prepared films are compared with the reflection electron diffraction and X-ray diffraction patterns. Especially, the effects of the sputtering voltage and partial pressure of oxygen were investigated con…
The crystal structure of the Mn3+-bearing epidote, piemontite, has been refined. For a crystal of composition, Cz6,PmPSll, refinement of the occupancies cf the two large, nominally calcium sites and the three non-equivalent octahedral sites, gives: where M = MnD. ,Feu. All of the (Mn, Fe) substitution for Al occurs in…
Carbon fibres graphitized at high temperature have been investigated by the techniques of x-ray diffraction and electron microscopy. The particular sample discussed here contains misoriented turbostratic crystals stacked end to end with widths in the range 20-110 Å; the maximum frequency occurs at 65 Å and this is als…
Abstract The thiol‐disulfide exchange reaction is shown to be applicable to cleavage of disulfide crosslinks in accelerated sulfur vulcanizates of natural rubber. The reaction, in conjunction with the previously reported selective cleavage of polysulfide crosslinks, is used to determine the distribution of crosslink t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystallization and dissolution of strontium sulfate in aqueous solutionJames Reid Campbell and G. H. NancollasCite this: J. Phys. Chem. 1969, 73, 6, 1735–1740Publication Date (Print):June 1, 1969Publication History Published online1 May 2002Published inissue 1 June 1969http…
Several gram-negative, polarly flagellated rods were isolated on the basis of their flocculent growth habit. Some of the isolates possessed a capsular matrix which is composed of exocellular fibrils. Other isolates did not appear to have a capsular matrix when examined with a bright-field microscope with or without th…
-A systematic X-ray diffraction study of the 10 homologues of n-azoxybenzenes has been performed. The structures of nematic and smectic mesophases as a function of the strength of the magnetic field and the temperature have been established.
The susceptibility of cellulose to enzymatic hydrolysis is determined largely by its accessibility to extracellular enzymes secreted by or bound on the surface of cellulolytic microorganisms. Direct physical contact between these enzymes and the cellulosic substrate molecules is an essential prerequisite to hydrolysis…
Abstract Nylon 66 films exhibiting form I melting behavior show the γ mechanical relaxation at −140°C. Samples which have form II melting behavior do not show this relaxation. The γ relaxation disappears when material having form I behavior is converted to material having form II behavior by annealing or by cold drawi…
A theory of the macroscopic twist which is a characteristic feature of the cholesteric liquid crystal phase is proposed. This is based on the presence of anharmonicity in the forces resisting the relative twist of neighboring planes of molecules and views the macroscopic twist as the rotational analog of thermal expan…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of Na2O.MgO.5Al2O3 [sodium oxide-magnesia-alumina] with reference to Na2O.5Al2O3 and other isotypal compoundsMax Bettman and Charles Richard PetersCite this: J. Phys. Chem. 1969, 73, 6, 1774–1780Publication Date (Print):June 1, 1969Publication History Publi…
A number of well-characterized silicate minerals and metal oxides have been analysed by the electron-probe technique in two different instruments with a range of accelerating potentials. Simple oxides and minerals have been used as standards for the elements Na to Ca and pure metals for the elements Ti to Ni. Factors…
Negative magneto-resistance is observed in poorly graphitized carbons at liquid nitrogen temperature or even higher. This peculiar phenomenon has been studied on pyrolytic graphite, as a model material. It is concluded that the negative magneto-resistance is a quantum phenomenon caused by a change of the carrier conce…
Measurements of the electrocaloric effect from 78 to 130 K were made on crystalline KH2PO4and are discussed in terms of the phenomenological theory of Devonshire and others. The predicted quadratic dependence of the electrocaloric effect upon applied field (and polarization) in the paraelectric phase was shown to occu…
Abstract Many derivatives of 1,3,3-trimethylspiro[indoline-2,2′-benzopyran] (1) exhibit photoreversible color changes in organic solvents. One of the derivatives 1,3,3-trimethylspiro[indoline-2,2′-benzopyran]-8′-carboxylic acid (2) shows “reverse photochromism” in polar solvents. The compound 2 exhibits a deep color i…
From a consideration of pit formation chemistry, equations have been derived that correspond to empirical equations developed by the NBS corrosion group. The theoretical equations' derivations show how soil resistivity and pH affect corrosion rates.
The mechanical properties, dislocation configurations and densities have been investigated in single crystals of copper deformed in the strain-rate range 10−4 to 104 sec−1. It was found that the flow stress of copper exhibits two regions of strain-rate sensitivity. Below strain rates of 103 sec−1 the flow stress was r…