Mati Mikkor

Silicon accelerometer responsive to three orthogonal force components and method for fabricating

An accelerometer fabricated from silicon which is responsive to the three orthogonal components of an applied force. A method is also disclosed for etching the accelerometer from a single silicon substrate. Three rectangular beams or cantilevers are formed each having vertical sidewalls lying in crystalline planes orthogonal to one another. Each of the beams is directly responsive to one of the three orthogonal force components.

Observation of electron standing waves in Mg by tunneling

Abstract Electron standing wave states in Mg films are observed by electron tunneling measurements. An electron group velocity is determined by this experiment.

Some phenomena which control sulfuric acid emission from automotive catalysts

With the use of a simulated exhaust system, the sulfuric acid and sulfur dioxide emission from a monolith noble- metal oxidation catalyst (Engelhard IIB) is measured. It was found that the storage rate of sulfur onto an initially sulfur-free catalyst decreases to a few percent of the sulfur rejection rate within 3-4 h. The amount of sulfur on the catalyst when the catalyst is in equilibrium with 20 ppm sulfur in the gas phase varies between 0.3 weight percent of the catalyst at about 400 degree C to 0.1 weight percent at 600 degree C. The sulfur can readily desorb from the catalyst if the gas phase sulfur content is lowered or if the catalyst temperature is increased. It was found that the conversion of sulfur dixoide to sulfuric acid reaches thermodynamic equilibrium at temperature of 400-500 degree C and space velocities of 30,000 H to the minus 1 power. These conditions correspond approximately to a small V8 engine at 20 mph cruise. In the simulated exhaust system without a catalyst, propylene, propane and hydrogen, which are present in automobile exhaust, reduce sulfuric acid to sulfur dioxide. This reduction appears to be a homogeneous reaction. /GMRL/