Materials Literature
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The nove approach is proposed to the synthesis of dyes with negative dichroism. The molecular models, which are adequate to the dichroic dyes, are shown. As an example of the approach, the synthesis and dischroic properties of some derivatives of the 2,2′-azomidazole are described. The time and contrast chracteristics…
The role of sulphide inclusions in the pitting and crevice corrosion of stainless steels is reviewed. It is noted that manganese sulphides, particularly those containing a central oxide core, are the most favourable sites for pit initiation. Replacing the manganese in the sulphide by chromium renders pit initiation mo…
Carbon tends to suppress the grain boundary fracture (GBFR) of α-iron, which is promoted by the segregation of phosphorus and other impurities to grain boundaries. This effect of carbon is due to its grain boundary segregation. It is shown in the present paper that the same effect of carbon is observed when hydrogen i…
The high temperature form of melanophlogite, 46 Si02. 6MI4 .2M12(M12 =CH4, N2; M14= C02, N2), is cubic with space group Pm3n and a= 13.436(3) A at 200°C. The mineral is isostructural with the cubic gas hydrates of type 1. Structure refinement with 667 independent reflections led to a weighted Rw= 0.040. Corner-sharing…
Abstract Mechanical processing of cotton cellulose by means of a fiber cutter resulted in the disaggregation and defiberation of fiber bundles, shortening of fiber length, and loss of degree of polymerization. It is evident that the mechanical energy supplied by shear forces is sufficient to cause homolytic scission o…
Croissance de Mo 3 Si par la methode TSZM et de Mo 5 Si 3 par la methode Czochralski. Caracterisation par diffraction de neutrons sur monocristal et sur poudre respectivement. Mo 3 Si cristallise dans Pm3n avec a=4,897 A, distance Mo−Mo la plus courte de 2,449 A. Mo 5 Si 3 cristallise dans In/mcm avec a=9,650 et c=4,9…
Dark currents on In0.53Ga0.47As mesa photodiodes can be reduced significantly by treating the surfaces with H2SO4:H2O2:XH2O (10≤X≤500) instead of the usual bromine-methanol etch. Using spectroscopic ellipsometry we show that peroxide etches form porous amorphous As or oxide overlayers according to whether the pH value…
Celion® 6000/PMR-15, Celion 6000/LARC-160, and Celion 6000/RK-99 graphite/polyimides were aged in circulating air ovens at temperatures of 202, 232, 260, and 288°C for various times up to 15 000 h. Three unidirectional specimens were studied: short-beam-shear (SBS), flexure, and 153-mm square panels. The interior regi…
A monolayer vesicle membrane with a (large) thiosuccinic acid and a (small) sulphonic acid head groups is orientated in such a way that 98% of the large head groups are on the outside and, correspondingly, 98% of the small head groupsd are inside.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction of metal ions and amino acids: possible mechanisms for the adsorption of amino acids on homoionic smectite claysAbha Gupta, Gilda H. Loew, and James LawlessCite this: Inorg. Chem. 1983, 22, 1, 111–120Publication Date (Print):January 1, 1983Publication History Pub…
The addition of ethylene-propylene random copolymer (EPR) to polypropylene (PP) homopolymer and the synthesis of polypropylene/ethylene-propylene block-sequential copolymer (PP/E-P) have been developed in order to improve upon the mechanical properties of PP resin. The block-sequential polypropylene/ ethylene-propylen…
A process of bioisosteric drug design is described whereby, in a manner analogous to synthesis, key portions of an effector molecule are successively replaced by pharmacophores or bioisosteres. This process, when applied to histamine, leads to the competitive histamine H2-receptor antagonist prototype 3-amino-5-(2-ami…
Surface chemical analysis by x-ray photoelectron spectroscopy (XPS) was undertaken on 316 LVM stainless steel in the attempt to better understand corrosion occurring in vivo. Samples were dipped in saline or in blood serum, corroded in serum or saline by the application of a 5 volt anodic potential, or corroded by fre…
A study of the surface tension of semi-dilute polymer solutions in theta solvent conditions is presented. Theoretical predictions are given for the two cases when the interface is attractive or repulsive. The Cahn approach for the interfacial tension is used in order to calculate the interfacial tension in the mean fi…
Actinide oxides used for nuclear reactor fuels have fluorite-type cubic structure. In this crystal structure, the self-diffusion coefficients of the constituent ions are closely related to its sublattice structure. Characteristics of the actinide oxides are reviewed with respect to self-diffusion and chemical diffusio…
Chitin and chemically modified chitins were spun to the fibers and their tensile properties were investigated together with the accessibility toward lysozyme. The fiber of partially deacetylated chitin showed the best properties in the tensile strength especially in a wet state. On the other hand, the accessibility of…
Vaccinium § Cyanococcus is defined by having verrucose twigs, dimorphic perennating buds, corymbose inflorescences, pedicels that are articulated with the calices, and berries that are pseudo-10-loculed. The section is endemic to North America and contains nine species, four of which have a hybrid origin. The ancestra…
Chondrosia reniformis sponge collagen, insoluble in its native form, was solubilized by chemical modification of lysyl residues. The solubilized sponge collagen had the same amino acid composition as insoluble collagen and the helicoidal tertiary structure was found by negative Cotton effect to be the same as in nativ…
The three principal elastic constants, K 11, K 11, and K 33, of the eutectic nematic liquid crystal mixture E7 have been determined as a function of temperature by following changes in the anisotropy of turbidity of a magnetically aligned specimen. The agreement with values of K 22 obtained by a previous capacitance-v…
A review is made of in vitro and animal investigations in which the properties of the non-ionic, ratio 3.0 contrast medium iohexol have been compared with those of other contrast media. The clinical importance of such investigations is discussed. In most investigations iohexol had less toxic effects than ionic ratio 1…