1,697 research outputs found
High voltage electrical insulation coating for refractory materials
Formula and process have been developed for coating refractory metal surfaces with high voltage electrical insulation for use at temperatures to 600 C. Coatings were specifically developed as an insulation for the surface of a perforated, molybdenum, ion-accelerator grid, but are not limited to this application
Method for fiberizing ceramic materials Patent
Process for fiberizing ceramic materials with high fusion temperatures and tensile strengt
Simulation of a non-invasive charge detector for quantum cellular automata
Information in a Quantum Cellular Automata architecture is encoded in the
polarizazion state of a cell, i.e., in the occupation numbers of the quantum
dots of which the cell is made up. Non-invasive charge detectors of single
electrons in a quantum dot are therefore needed, and recent experiments have
shown that a quantum constriction electrostatically coupled to the quantum dot
may be a viable solution. We have performed a numerical simulation of a system
made of a quantum dot and a nearby quantum point contact defined, by means of
depleting metal gates, in a two-dimensional electron gas at a GaAs/AlGaAs
heterointerface. We have computed the occupancy of each dot and the resistance
of the quantum wire as a function of the voltage applied to the plunger gate,
and have derived design criteria for achieving optimal sensitivity.Comment: 8 pages, RevTeX, epsf, 5 figure
Ingestive behaviour and physiology of the medicinal leech
Ingestion lasts 25 min in Hirudo medicinalis and is characterized by pharyngeal peristalsis which fills the crop. This peristalsis has an initial rate of 2.4 Hz which decays smoothly to 1.2 Hz at termination of ingestion. During ingestion, the leech body wall undergoes peristalsis which appears to aid in filling the crop diverticula. Body peristalsis begins at a rate of 10 min^(-1) and decreases linearly to 2 min^(-1) at termination. The body also undergoes dorsoventral flexions when blood flow is occluded. Blood meal size increases slightly with leech size: 8.4 g for 1-g leeches and 9.7 g for 2-g leeches. However, relative meal size decreases markedly with increasing animal size; from 8.15 times body mass for 1-g to 4.80 times for 2-g leeches. When intact leeches were exposed to micromolar concentrations of serotonin, there was an increase in the rate of pharyngeal peristalsis and the size of the blood meals. Leeches excrete the plasma from their ingested blood meals. Excretion is activated during ingestion, which increases feeding efficiency by increasing the proportion of blood cells in the ingestate. Excretion continues for 4–6 days following ingestion, removing all the remaining plasma from the ingestate. Leech ingestion comprises stereotyped muscular movements, secretion of saliva and excretion of plasma. A strikingly similar feeding physiology is seen in the blood-sucking insect Rhodnius, and we suggest that efficient sanguivory may require the convergent evolution of similar ingestive mechanisms
- …