Materials Literature
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Flexural strength and fracture toughness of molybdenum disilicide and its composites with 10 wt% TiB 2 and 10 wt% TiB 2 + 10 wt% SiC, synthesized by the hot‐pressing technique, were evaluated as a function of temperature, ranging from ambient temperature to 1600°C. Results show that the composites have higher strength…
Lead titanate (PbTiO 3 ) is difficult to sinter without additives, even when a spark‐plasma‐sintering technique is applied. The high tetragonality, c / a , of PbTiO 3 causes destructive strain after sintering. We found that a sintered body of PbTiO 3 could be obtained, when the PbO/TiO 2 value was <0.9. However, de…
For generations humans have been engineering pillars that have more than one function. The giant stone pillars of the 9th-century Cordoba Mosque in Andalusia, Spain, for example, provide both structural stability and aesthetic appeal. Now researchers in the US have built pillar structures at the nanometre scale that c…
The properties of wavelength-division multiplexed (WDM) narrowband filters used in tilted collimated light are described. The wavelength shift for s polarization in a low-index-spacer filter is larger than that for p polarization when the filter is tilted, but it is smaller in a high-index-spacer filter. Therefore the…
This paper presents the results of studies on a range of different catalyst substrates warmed by engine exhaust. Engine speeds were in the range 1200–3000 r/min. One substrate was non-washcoated, four were washcoated but non-reactive and four were washcoated and reactive. The temperature at four locations within the n…
To account for the dependence of the crystal nucleation temperature in Co–Pd melts over the entire range from 50 to 100 at.% Co it is necessary to incorporate a contribution to the driving free energy that derives from the difference in magnetic free energies between liquid and melt. A simple molecular-field model pro…
Efficient electroluminescence (EL) is obtained at low voltages (3 V) from n + -type silicon/electrochemically oxidized thin nanocrystalline porous silicon (PS)/amorphous carbon/indium tin oxide (ITO) junctions. The carbon film acts as an efficient mechanical and electrical buffer layer between PS and ITO. As a result,…
Abstract In previous computer simulation studies of the atomic structure of twin boundaries and defects such as twinning dislocations in the HCP metals, conventional periodic boundary conditions along the dislocation line and fixed conditions in the other two directions were used. Thus, extensive defect motion could n…
We have measured the rheological properties of two cholesterol derivatives (cholesteryl myristate and cholesteryl nonanoate) in the vicinity of their cholesteric–smecticA transitions. The results for the two compounds differ qualitatively, and are in agreement with results based on optical observations of new defects…
We present a phase field theory for the nucleation and growth of one and two phase crystals solidifying with different crystallographic orientations in binary alloys. The accuracy of the model is tested for crystal nucleation in single component systems. It is shown that without adjustable parameters the height of the…
Conventional definitions of velocities associated with the propagation of modulated waves cannot clearly describe the behavior of the wave packet in a multidimensional dispersive medium. The conventional definition of the phase velocity, which is perpendicular to the wave front, is a special case of the generalized ph…
Abstract The electrolytic conductivity and solution viscosity of some strong polycations, which possess the ammonium quaternary centers either attached to an acrylic macromolecular chain (polycation PDMAEMQ type), or in the backbone (polycation PCA type), have been measured in order to identify how charge density, pol…
In the present study, the effect of various solid state diffusion times (8 h, 16 h, 24 h) on the microstructure of diffusion alloyed samples and its corresponding composition and microhardness changes were investigated at 480°C. Optical microscopy, SEM, EDX and microhardness techniques were used to examine the treated…
Beryllium irradiated by neutrons with energies above 0.7 MeV undergoes (n,α) and (n,2n) reactions. The Be(n,α) reaction results in subsequent buildup of 6Li and 3He isotopes with large thermal neutron absorption cross sections causing poisoning of irradiated beryllium. The amount of the poison isotopes depends on the…
Protection of thermolabile metabolites and coenzymes is a somewhat neglected but essential aspect of the molecular physiology of hyperthermophiles. Detailed information about the mechanisms used by thermophiles to protect these thermolabile metabolites and coenzymes is still scarce. A case in point is CP (carbamoyl ph…
Single-walled carbon nanotubes (SWNTs) have been used as growth templates for spatially confined crystal growth. The comparative crystallization and high-resolution transmission electron microscopy imaging properties of simple binary halides formed by the alkali iodides MI (M = Li, K, Na, Rb and Cs) within SWNTs are d…
A new form of biomineralization in the pineal gland of the human brain has been studied. It consists of small crystals that are less than 20 /spl mu/m in length and that are completely distinct from the often-observed mulberry-type hydroxyapatite concretions. Cubic, hexagonal and cylindrical morphologies have been ide…
The influence of the welding process and post-welding heat treatment on the abrasive wear resistance of iron based hardfacing overlays (Fe–6Cr–0.5C) is reported. Overlays were deposited by shielded metal arc (SMA) and tungsten inert gas (TIG) welding processes on structural steel using a commercially available surfaci…
A mild, catalytic dehydrocoupling route to aminoboranes and borazine derivatives from either primary or secondary amine-borane adducts has been developed using late transition metal complexes as precatalysts. The dehydrocoupling of Me 2 NH·BH 3 was found to be catalyzed by 0.5 mol% [Rh(1,5-cod)(μ-Cl)] 2 in solution at…
Abstract A new series of molecule-based magnets, including crown thioether (9S3 = 1,4,7-trithiacyclononane) complexes of transition metals (Ni, Co, Cu), are presented. TCNQ salts [M(9S3)2](TCNQ)2 (M = Ni, Co) are one-dimensional (1D), antiferromagnetic (AF) complexes with an intra-chain interaction J = −3.9 K and −1.3…