Abstract: A photodetector (10) includes a substrate (12) having a surface; a first layer (14) of semiconductor material that is disposed above the surface, the first layer containing a first dopant at a first concentration for having a first type of electrical conductivity; and a second layer (16) of semiconductor material overlying the first layer. The second layer contains a second dopant at a second concentration for having a second type of electrical conductivity and forms a first p-n junction (15) with the first layer. The second layer is compositionally graded through at least a portion of a thickness thereof from wider bandgap semiconductor material to narrower bandgap in a direction away from the p-n junction. The compositional grading can be done in a substantially linear fashion, or in a substantially non-linear fashion, e.g., in a stepped manner.

Abstract: A unit cell (10) of a readout integrated circuit is constructed and operated so as to temporally align an image obtained in a first spectral band with a an image obtained in a second spectral band. A method operates, during a frame period, to sub-frame average a first signal detected in the first spectral band by a multi-spectral detector (12), to sub-frame average a first signal detected in the second spectral band by the multi-spectral detector, and to sub-frame average a second signal detected in the first spectral band by the multi-spectral detector. The method then reads out the sub-frame averaged signals for each spectral band. The sub-frame averaged may be read out simultaneously from the unit cell.

Abstract: A photodetector (10) includes a substrate (12) having a surface; a first layer (14) of semiconductor material that is disposed above the surface, the first layer containing a first dopant at a first concentration for having a first type of electrical conductivity; and a second layer (16) of semiconductor material overlying the first layer. The second layer contains a second dopant at a second concentration for having a second type of electrical conductivity and forms a first p-n junction (15) with the first layer. The second layer is compositionally graded through at least a portion of a thickness thereof from wider bandgap semiconductor material to narrower bandgap in a direction away from the p-n junction. The compositional grading can be done in a substantially linear fashion, or in a substantially non-linear fashion, e.g., in a stepped manner.

Abstract: A suspension system for the ground engaging powered and/or caster wheels of a power wheelchair utilizes three links, two of which are universally pivotally connected between the frame of the wheelchair and a wheel mounting transaxle housing or subframe so that the wheels can tilt relative to the frame of the wheelchair in a vertical plane. A third link is connected between the vehicle frame and the wheel mounting structure which can only pivot in a vertical plane, thus restraining the wheels from any lateral displacement relative to the vehicle frame. Fluid cylinders operable between the links and the vehicle frame provide cushioning of the frame and also, by subtraction of fluid from the fluid cylinders, can lower the entire frame of the wheelchair relative to the ground engaging wheels to permit the wheelchair and occupant to drive into the side door opening of a conventional van.

Abstract: An electrically powered vehicle having two primary ground engaging wheels operatively connected to a driving motor by an automatic transmission and to a steering motor by a shiftable bevel gear which permits opposite variations in rotational speed of the ground engaging wheels.

Abstract: A power-driven and steered wheelchair comprises a pair of ground-engaging wheels mounted in laterally-spaced relationship to a frame carrying a seat for an occupant and supporting the power source and a transaxle transmission for imparting parting both driving and steering power to the ground-engaging wheels. Steering is accomplished by employing separate planetary drive mechanisms for each of the primary ground-engaging wheels and imparting rotation in opposite directions to the ring gears of such planetary drive mechanisms to effect the rotation of one wheel at a greater speed than the other wheel in either a forward or rearward direction, thus producing power steering of the wheelchair.

Abstract: In the froth flotation of ore in a column, the froth/pulp interface level and the efficiency of the froth washing operation are controlled by determining a profile of temperatures measured in the froth layer and slurry below the interface. Temperatures are measured with temperature sensing elements immersed in the froth layer and extending to below the interface level. The measured profile is compared with a target profile and deviations are corrected by changing the tailings flowrate or the washwater flowrate to return a measured profile to the target profile. An inflection point in the profile occurs at the interface level. The inflection point in a measured profile is compared with a level set point, and a deviation from set point value is corrected by increasing or decreasing the flow of tailings whereby the interface level returns to its set point.