3,377 research outputs found
Sintered silicon nitride workpiece
A description is given of a sintering method for silicon nitride. A detailed explanation of the invention is presented. Four procedures for the sintering process are described
Silicon nitride sintered body
The sintering of silicon carbide and it production are described. The method of production is by calcination in which molding is followed by sintering without compression. The invention improves the composition of the silicon carbide ceramic. Six examples of the invention are illustrated and discussed
Silicon carbide material sintered bodies manufacturing
A method is described for producing a high density silicon carbide sintering substance which contains aluminum oxide. The sintering is done in CO gas atmosphere, which is kept at 2 to 20 atmospheric pressures
Chemical Identification of the Radioelements Produced from Carbon and Boron by Deuteron Bombardment
Chemical experiments were made on the radioactive substances resulting from the bombardment of carbon and boron by deuterons. Carbon is shown to yield an isotope of nitrogen and boron an isotope of carbon. The nitrogen so formed has a half-life of 10.5 minutes while that found by Curie and Joliot on bombardment of boron with alpha-particles has a half-life of 14 minutes. These facts are discussed
Relativistic Particle Acceleration in a Folded Current Sheet
Two-dimensional particle simulations of a relativistic Harris current sheet
of pair plasmashave demonstrated that the system is unstable to the
relativistic drift kink instability (RDKI) and that a new kind of acceleration
process takes place in the deformed current sheet. This process contributes to
the generation of non-thermal particles and contributes to the fast magnetic
dissipation in the current sheet structure. The acceleration mechanism and a
brief comparison with relativistic magnetic reconnection are presented.Comment: 11 preprint pages, including 3 .eps figure
High-Tc superconductivity in entirely end-bonded multi-walled carbon nanotubes
We report that entirely end-bonded multi-walled carbon nanotubes (MWNTs) can
show superconductivity with the transition temperature Tc as high as 12K that
is approximately 40-times larger than those reported in ropes of single-walled
nanotubes. We find that emergence of this superconductivity is very sensitive
to junction structures of Au electrode/MWNTs. This reveals that only MWNTs with
optimal numbers of electrically activated shells, which are realized by the
end-bonding, can allow the superconductivity due to inter shell effects.Comment: 5 page
Transition of amorphous to crystalline oxide film in initial oxide overgrowth on liquid metals
It is important to understand the mechanism of oxidation in the initial stage on the free surface of liquid metals. Mittemeijer and co-workers recently developed a thermodynamic model to study the oxide overgrowth on a solid metal surface. Based on this model, we have developed a thermodynamic model to analyse the thermodynamic stability of oxide overgrowth on liquid metals. The thermodynamic model calculation revealed that the amorphous oxide phase is thermodynamically preferred up to 1.3 and 0.35 nm respectively, in the initial oxide overgrowth on liquid Al and Ga at the corresponding melting point. However, the amorphous phase is thermodynamically unstable in the initial oxide overgrowth on liquid Mg. The thermodynamic stability of amorphous phase in the Al and Ga oxide systems is attributed to lower sums of surface and interfacial energies for amorphous phases, compared to that of the corresponding crystalline phases.Financial support under grant EP/H026177/1 from the EPSRC was used
Functional Metabolomics Reveals Novel Active Products in the DHA Metabolome
Endogenous mechanisms for successful resolution of an acute inflammatory response and the local return to homeostasis are of interest because excessive inflammation underlies many human diseases. In this review, we provide an update and overview of functional metabolomics that identified a new bioactive metabolome of docosahexaenoic acid (DHA). Systematic studies revealed that DHA was converted to DHEA-derived novel bioactive products as well as aspirin-triggered forms of protectins (AT-PD1). The new oxygenated DHEA-derived products blocked PMN chemotaxis, reduced P-selectin expression and platelet-leukocyte adhesion, and showed organ protection in ischemia/reperfusion injury. These products activated cannabinoid receptor (CB2 receptor) and not CB1 receptors. The AT-PD1 reduced neutrophil (PMN) recruitment in murine peritonitis. With human cells, AT-PD1 decreased transendothelial PMN migration as well as enhanced efferocytosis of apoptotic human PMN by macrophages. The recent findings reviewed here indicate that DHEA oxidative metabolism and aspirin-triggered conversion of DHA produce potent novel molecules with anti-inflammatory and organ-protective properties, opening the DHA metabolome functional roles
Meissner effect in honeycomb arrays of multi-walled carbon nanotubes
We report Meissner effect for type-II superconductors with a maximum Tc of 19
K, which is the highest value among those in new-carbon related
superconductors, found in the honeycomb arrays of multi-walled CNTs (MWNTs).
Drastic reduction of ferromagnetic catalyst and efficient growth of MWNTs by
deoxidization of catalyst make the finding possible. The weak magnetic
anisotropy, superconductive coherence length (- 7 nm), and disappearance of the
Meissner effect after dissolving array structure indicate that the graphite
structure of an MWNT and those intertube coupling in the honeycomb array are
dominant factors for the mechanism.Comment: 6 page
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