Materials Literature
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A correlation between the direction of the tetrad (double-double) effect in the lanthanide and actinide series and coordination number (CN) is discussed on experimental and theoretical grounds. Some examples of determining the CN values of the f-block elements in solution complexes using the tetrad effect are reviewed…
Spectra and lifetime measurements of the strongly mixed B″ 3 Π u and B 3 Σ u − states of 32 S 2 are presented covering v′ = 710 of the B state and v′ = 1221 of the B″ state. This extends our earlier work (M. E. Green and C. M. Western, J. Chem. Phys., 1996, 104, 848) to just above the first dissociation limit ( 3 P +…
Knitted fabric composites have certain advantages over woven composites, particularly in their ability to conform to complicated contours. As a consequence, however, they demonstrate inferior mechanical characteristics compared to woven materials as a direct result of the presence of bent fibers. Such a knitted fabric…
A colloidal route has been used to make zirconia tubes that were found to have excellent mechanical properties with strengths >500 MPa, surviving rapid heating conditions of 200°C/min to operating temperatures of 800°C. These tubes were put into a 200 tube solid oxide fuel cell(SOFC) reactor. The reactor was computer…
The accuracy of a stylus probe method in measuring localized magnetic properties of grain-oriented silicon steel sheet was investigated and its application was studied. The measuring error for the localized flux density was determined to be less than 1.7% for the load onto the stylus tip lighter than 300g when the yok…
It seems that there is a confusion of the critical exponent of conductivity of composites which is caused by the way of determining the percolation threshold. In this paper, the percolation behavior, the critical exponent of conductivity and the electrical conduction mechanism of carbon black-polyethylene composites a…
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We introduce a method for finding weak structural similarities in a set of protein structures. Proteins are considered at their secondary structure level. The method uses a rigorous graph-theoretical algorithm which finds all structural similarities. Protein structures are modelled as undirected labelled graphs, the s…
Cadmium coatings have in the past been frequently used as protective coatings against corrosion of metallic structures, but cadmium is now known to be a polluting substance, dangerous for human health and the environment. Since 1991, a European directive has regulated the use of cadmium coatings in industry. Other coa…
Pyrazine-2,3-dicarbonitriles may be used as precursors for aza analogs of phthalocyanines (AzaPc's).Presently AzaPc's are receiving considerable attention, mainly due to their increased solubility compared to the parent phthalocyanines.Enhanced solubility is caused by the eight additional nitrogens in the macrocycle a…
In this paper, a small-angle neutron scattering study of gammaII-crystallins near their isoelectric point is presented. The experiments were carried out using protein concentrations of 5.7-85.7 mg/ml at temperatures in the range 11 -60 degrees C. The experimental data were analyzed using an ellipsoidal model for intra…
The 15-tert-butyl-5-oxophlorin 1 forms a stable, neutral π-radical species 2, in high yield; the 13,17-bis-unsubstituted 5-oxophlorin analogue 5, under similar conditions, affords the 15-iso-5-oxophlorin 6 and 15-hydroxy compound 7 (both characterized by X-ray crystallography), the latter demonstrating the trapping of…
TEMPO (2,2,6,6-tetramethylpiperidinyloxy) radical 1 and its derivatives 2–5 are found to form charge-transfer complexes with some acceptors such as TCNQF 4 (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) or DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone) being isolated as solid substances.
X-ray diffraction (XRD), differential thermal analysis (DTA) and 27Al and 29Si solid state MAS-NMR techniques were used to monitor the fractionation steps of a brazilian smectite, previously crushed, from Campina Grande, Paraíba. The sand, silt and clay fractions were obtained by physical and chemical treatments. The…
PHYSICAL MODEL of shear strain rate produced by active micro-shear bands in metals is formulated and mathematical idealization of micro-shear bands system by means of the theory of singular surface of order one is proposed. Extension of the known averaging procedure over the representative volume element traversed by…
The coordination environment of Ti in eight Ti-bearing glasses of the Na Si ° -Na,Ti ° join (NTS) and in six ATY2 glasses (A20Ti02.2Y02, with A = Na, K, ~r Rb and y4 ;: Si or Ge) was determined using high-resolution, X-ray absorption near-edge structure (XANES) spectroscopy at the Ti K edge in ambient conditions. Five…
The purpose of this paper is to present the relationship between mechanical properties and thermoelectric properties of p-type Bi-Te polycrystalline materials. Semiconducting ceramics of p-type bismuth telluride were prepared by a hot press method. Their bending strength was over 40MPa and decreased with increasing pa…
The influence of grain size and grain boundary delta phase on the smooth and notch high cycle fatigue property at room temperature and 650% was investigated.This paper attempts to correlate the microstructure and fatigue property obtained during the initial development phase and certification of bar stock for compress…
Synthesis of β-SiAlON whiskers from pyrophyllite was investigated and the growth of the whiskers was explained by VLS (vapor-liquid-solid) mechanism. During heating, Fe2O3 in pyrophyllite was reduced by carbon derived from resin to Fe which further reacted with C to form an alloy (FexCy). When the temperature was abov…
Si 3 N 4 /MoSi 2 and Si 3 N 4 /WSi 2 composites were prepared by reaction‐bonding processes using as starting materials powder mixtures of Si‐Mo and Si‐W, respectively. A presintering step in an At‐base atmosphere was used before nitriding for the formation of MoSi 2 and WSi 2 ; the nitridation in a N 2 ‐base atmosphe…