Materials Literature
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IrSb3 and the isostructural compounds RhSb3 and CoSb3 were recently identified as new promising thermoelectric materials (Caillat et al. 1993a). The use of these materials in thermoelectric devices requires that their properties shall not change over long periods of time at operation temperature. Temperature stability…
Effects of B content on the sintering behavior of Nd15Fe85−xBx (x=4–10 at%) alloy powders were investigated through microstructural observations, and measurements of DTA, linear shrinkage and magnetic properties. In the case of x≥6 at%, a liquid phase forms from ternary eutectic reaction of Nd-rich, Nd2Fe14B and Nd1.1…
This note discusses some basic concepts underlying isotropic material failure criteria under multiaxial loadings. It also describes the shapes and features of the associated failure surfaces in three-dimensional stress space. Failure criteria for ductile materials are first reviewed. They are then generalized so that…
The pyrolysis of a low-oxygen SiC fiber, prepared by the electron-irradiation curing method, has been investigated in N2 atmosphere at temperatures from 1673 to 1973K. Then, the pyrolytic behavior in N2 was compared with that in Ar. The fiber absorbed a considerable amount of nitrogen, and consequently, the mass loss…
π-Cation radicals of iron(III) derivatives of some deformed porphyrins have been characterised using UV/VIS, IR and 1H NMR spectroscopy and by magnetic susceptibility measurements. The deformation in these systems has been induced by a covalent attachment of short bridging chains across the porphyrin periphery. Molecu…
Many studies have been made on liquid bridges between particles, but the mechanism of liquid bridge formation and its adhesion force when the bridge is in an equibrium condition with the surrounding humidity has not been theoretically clarified. A study has been made on this subject and a new theory is introduced in t…
Scanning confocal light microscopy offers an alternative three-dimensional imaging technique that can allow a fresh view of surfaces. It can image samples that are wet, coated, or porous and cope with highly irregular surfaces for which the desired depth of field is difficult to study by other methods. Its principal a…
Five crystalline phases have been characterized in the perovskite layer compound (C10H21NH3)2CuCl4, using differential scanning calorimetry, X-ray diffraction and infrared spectroscopy. The ordered phase V contains three types of hydrocarbon chains; two of them have an almost extended configuration with a gauche bond…
Advanced materials are receiving increasing attention for applications requiring high‐leverage materials possessing potentially high pay‐offs. While the low‐rate deformation response of a broad range of advanced materials is receiving intense scientific study, increased utilization of these material classes under dyna…
An irradiation of solid samples with x-rays causes an electron emission from the sample surface, owing to photoabsorption. These electrons can be detected under vacuum conditions and are photo, Auger and secondary electrons. Due to inelastic collisions most of these electrons have lost some of their original kinetic e…
In relation to the investigation of their electrochemical properties we prepared 24 pyridinium derivatives ( I , IV , V , VI , VII ) with alkyl and aryl substituents in positions 1, 2, 4 and 6, and 19 derivatives with two pyridinium nuclei ( II , III , VIII , IX , X ) connected by an aliphatic or an aromatic chain. Al…
In February 1953, forty years ago, the first synthetic diamonds were made in Sweden. This was then the culmination of more than ten years’ work. In 1942, ASEA started with experiments of converting graphite into diamonds under high pressures and high temperatures. The difficulties were bigger than anyone could have im…
Friction and wear tests from room temperature to 1000°C were carried out for two kinds of mullite ceramics, and compared with those of alumina ceramics. Samples prepared from the natural raw materials (M-1) and the sol-gel method (M-2) were used. The former contained considerable amount of impurities and they formed g…
Co K-edge EXAFS data of some (porphinato)cobalt(III) complexes with amine ligands in chloroform solution are reported. Data for the following compounds were collected: chloro(tetraphenylporphinato)cobalt(III)(TPPCoCl) complexed with pyridine (A), isoquinoline (B) and cyclohexylamine (C) and 4-methylpiperidine complexe…
The internal reinforcement of Douglas-fir by glass or basalt fibers impregnated with resorcinol-phenol-formaldehyde or polymeric diphenylmethanediisocyanate bonding resins has been investigated. The objective was to evaluate the improvement in composite properties by the use of silane coupling agents. Fibers were trea…
Vielzeuf and Holloway (1988) experimentally studied the melting of a metapelite under fluidabsent conditions. At 10 kbar, three main stages of melting were distinguished : I) The first melting occurs below 800~ and corresponds to the breakdown of muscovite via reactions such as Ms + Bt + PI + Qtz + V = M + Als;Ms + PI…
The one-electron donor (reducing) sites and their strength distribution on hydrotalcite, MgO and Al2O3 surfaces have been measured with a series of electron acceptor molecules (nitrobenzene, m-dinitrobenzene, sym-trinitrobenzene, 2,4-dinitrotoluene, tetracyanoethene), whose electron affinity (Eea) values are different…
These experimental studies are mainly concerned with the matter ejection from the free surface and the bulk microspalling of the sample near the free surface. We describe an experimental technique using flash X‐ray radiography in order to study the shock‐induced ejection and microspalling. Experiments have been achiev…
Ionomers are predominantly nonpolar polymers that contain a small amount of bonded salt groups. Microphase separation of ion-rich microdomains occurs as a consequence of the thermodynamic incompatibility of the salt groups and the polymer matrix and associative interactions between salt groups. Associations of the sal…
As indicated by thin layer cyclic voltammetry, electrocrystallization of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) at the second oxidation potential affords a charge-transfer salt of 1 : 1 stoichiometry, i.e.(BEDT-TTF)PF6·0.5CH2Cl2, the crystal structure of which is presented.