Materials Literature
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Abstract Generally, fracture toughness and fracture stress of ceramics depend on crack length, notch root radius and grain size. These three parameters are most important when assessing the integrity of structural ceramic members and developing high‐performance ceramics. A new failure criterion called the process zone…
SUMMARY: Accumulation of Cs+ by Chlorella salina was 28-fold greater in cells incubated in the presence than in the absence of 0.5 M-NaCl. An approximate 70% removal of external Cs+ resulted after 15 h incubation of cells with 50 μ;M-CsCl and 0.5 M-NaCl. LiCl also had a stimulatory effect on Cs+ uptake, although manni…
Castor oil is a relatively inexpensive and renewable source of hydroxyl groups. This makes use of castor oil in polyols for polyurethane very attractive. We have prepared a simple castor oil based polyol for rigid polyurethane foam application. The polyol is a physical blend of castor oil and glycerol. Glycerol acts a…
Abstract Measurements on polyaniline using dielectric analysis (DEA, −50°C to 240°C, 0,4 Hz to 10 5 Hz), differential scanning calorimetry (DSC, 30°C to 240°C) and infrared spectroscopy (IR) after heat treatment from 25°C to 300°C are carried out. After conversion of DEA results to complex electric modulus, the conduc…
Abstract Samples of paracyanogen were prepared by the pyrolysis of silver cyanide, the photolysis of cyanogen, and by sputtering a carbon electrode in a nitrogen plasma. This work was undertaken to establish whether these materials are alike and to derive structural information on the basis of FT‐IR, 13 C‐MAS—NMR, and…
In this work we use transmission electron microscopy to identify extended lattice defects which result from O + ion implantation at a dose of 1.3×10 15 /cm 2 into Sn-doped In 2 O 3 at room temperature. Measurement of the resistivity, mobility, carrier density, and transmissivity to visible light as a function of impla…
To eliminate the heat loss effects in thermal diffusivity measurements using the ac calorimetric method, it is proposed theoretically that simultaneous measurement of the effective thermal diffusivities from both the amplitude decay of the ac temperature waves propagating along the surface of a thin sample and its pha…
En raison de la nature particulière des cours d'eau de son bassin, l'Agence de l'Eau Artois-Picardie a adopté en 1988 les diatomées et les indices diatomiques pour l'estimation de la qualité biologique de l'eau. Six indices ont été testés. Les résultats montrent que l'IPS ou Indice de Polluosensibilité Spécifique (Cos…
Magnetic ordering phenomena in mixed-metal assemblies {NBu4[Fe(II)M(III)(ox)3]}3∞ (M=Cr (1), Fe (2)) were studied by using 57Fe Moessbauer spectroscopy, where NBu4 +=tetra(n-butyl)ammonium ion, ox2-=oxalate ion. Nuclear Zeeman splittings were observed in the Moessbauer spectra of both 1 and 2 at low temperatures (belo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTClusters of clusters. 25. Synthesis and structure of a new [gold-silver]-38-metal-atom cluster [(Ph3P)14Au18Ag20Cl12]Cl2 and its implications with regard to intracavity chemistry on metal cluster surfacesBoon K. Teo, Xiaobo Shi, and Hong ZhangCite this: Inorg. Chem. 1993, 32…
The Ni(II) and higher valence states redox behavior of Ni and Ni/PTFE deposited electrodes fabricated by electroless plating are compared using cyclic voltammetry and potentiodynamic techniques, for their ability to evolve O 2 and oxidize ethanol in 1 mol dm −3 KOH . In this study, a Ni/PTFE electrode formed in a 6 g…
The effect of surface oxygen concentration of silicon nitride powders on the properties of resulting ceramics was studied. A high‐purity silicon nitride powder was treated physically and chemically to modify its surface oxygen content. The resulting powders were hot‐pressed into dense ceramics using 6 wt% yttria as a…
Abstract The mechanical hysteresis of a polyether polyurethane thermoplastic elastomer was studied as a function of temperature, percent strain, and deformation energy. Hysteresis values remained small at low temperatures when the extent of the sample deformation did not disrupt the glassy matrix. This was readily evi…
All three viscometric functions are investigated as a function of shear rate for lyotropic solutions of hydroxypropyl cellulose (HPC). Through the use of m-cresol as the solvent, it was possible to investigate liquid crystal solutions at lower polymer volume fractions than have previously been studied for HPC. We find…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReductive quenching of the emission of trans-dioxo(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane)osmium(VI) in waterSiegfried Schindler, Edward W. Castner Jr., Carol Creutz, and Norman SutinCite this: Inorg. Chem. 1993, 32, 20, 4200–4208Publication Date (Print):Sept…
We conduct a numerical study of the dynamic behavior of a dense hard-sphere fluid by deriving and integrating a set of Langevin equations. The statics of the system is described by a free-energy functional of the Ramakrishnan-Yussouff form. We find that the system exhibits glassy behavior as evidenced through a stretc…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthetic, structural, and spectroscopic studies on copper(II), copper(I), and silver(I) complexes of a series of pyridazinophane and phthalazinophane macrocycles. Unusual extended metallocyclic structuresLiqin Chen, Laurence K. Thompson, Santokh S. Tandon, and John N. Brids…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFully aromatic liquid-crystalline polyesters of phenyl-substituted 4,4'-biphenols and 1,1'-binaphthyl-4,4'-diol with either 2-bromoterephthalic acid or 2-phenylterephthalic acidPradip K. Bhowmik and Haesook HanCite this: Macromolecules 1993, 26, 20, 5287–5294Publication Date…
Renaut bodies (RB) are fusiform endoneurial structures preferentially found at sites of nerve entrapment, often occupying more than 30% of the cross-sectional area of a nerve fascicle. Their composition and significance, however, are still incompletely understood. In this study, further evidence for the link between t…
Abstract The optical absorption properties of Fe‐impurity centers in SrTiO 3 can be used to probe in‐situ the oxygen activity in the sample. The response of the absorbance upon a sudden change the oxygen partial pressure allows the precise investigation of the kinetics of oxygen incorporation (excorporation). In contr…