Abstract:
A liquid dispensing device. The liquid dispensing device has a tray for holding a liquid at a relatively constant level. A syringe is used for drawing fluid from the tray. A liquid container containing a liquid is positioned upside-down in the tray. Atmospheric pressure on the liquid in the tray and a vacuum inside the liquid container prevents liquid from draining from the container except when the liquid level in the tray drops to a level sufficient to allow air into the liquid container and to allow fluid to flow from the liquid container into the tray. The fluid flows from the liquid container into the tray until the level of liquid in the tray returns to the relatively constant level. The positioning of the syringe for drawing fluid is simplified in that the level of fluid in the tray is maintained at an approximately constant level despite withdrawal of quantities of fluid from the tray.
Abstract:
A space diversity antenna system provided with dither circuitry in the signal path to one of the antennas to switch a circuit element in and out of the signal path at a high rate. The circuit element can be an amplitude attenuator or a phase changer. This switching results in the substantial elimination of nulling between the two antennas.
Abstract:
MOMOM structural geometry and fabrication techniques are is disclosed. First and second metal layer strips (6 and 10) are supported on an insulating substrate (4) and have vertically overlapped portions sandwiched between insulating layers (8, 12). A generally vertical side (18) is defined through the layers to the substrate to expose vertical edges (20, 24) of the metal layers which are oxidized (32, 34) and covered by a third metal layer (44) extending therebetween. In the preferred embodiment, the middle insulating layer (8) is undercut (28), oxidized (36, 40), and filled with metallization (50), to provide a vertical rectilinear conduction path.
Abstract:
A power JFET (2) has a common drift region (4) between a pair of spaced first and second stacks (6, 8) of alternating conductivity type layers (10-14 and 15-19) forming a plurality of channels (11, 13, 16 and 18). The JFET has an ON state conducting bidirectional current horizontally through the common drift region and the channels. The channels are stacked vertically, and the JFET has an OFF state blocking current flow through the channels due to vertical depletion pinch-off. Field shaping and high blocking voltage capability are provided. Particular main terminal and gate structure is disclosed.
Abstract:
Lateral FET structure is disclosed with an insulative region such as porous silicon filled with oxide formed in the drift region to divert the drift region current path and increase the length thereof to afford higher OFF state blocking voltage without increasing lateral dimensions. Combinations involving bidirectional power switching structures are also disclosed, as well as a multicell matrix array.
Abstract:
Lateral FET structure is disclosed for bidirectional power switching, including AC application. Voltage blocking capability is enhanced by field shaping in the drift region. In the OFF state, depletion from a channel region junction and from a field shaping region junction spread toward each other through the drift region to straighten out field lines and prevent curvature crowding of field lines at edges of notch means extending into the drift region and separating a pair of source regions and a pair of channel regions.
Abstract:
Bidirectional power FET structure is disclosed with high OFF state voltage blocking capability. A shielding electrode is insulated between first and second gate electrodes in a notch between laterally spaced source regions and channel regions joined by a common drift region around the bottom of the notch. The shielding electrode is ohmically connected to the substrate containing the common drift region to be at the same potential level thereof and within a single junction drop of a respective main electrode across the junction between the respective channel containing region and drift region. The steering diode function for referencing the shielding electrode is performed by junctions already present in the integrated structure, eliminating the need for discrete dedicated steering diodes. The shielding electrode prevents the electric field gradient toward the gate electrode on one side of the notch from inducing depletion in the drift region along the opposite side of the notch. This prevents unwanted inducement of conduction channels in the drift region during the OFF state of the FET.
Abstract:
A blocking device for remote, selective blocking of a cold stream used in a protein crystal annealing process during X-ray protein crystallography includes a blocking member adapted to be selectively moved between at least a blocking position where the blocking member blocks the cold stream and a non-blocking position where the blocking member does not block the cold stream, and an actuation mechanism adapted to impart movement to the blocking member to cause the blocking member to be selectively moved between at least the blocking position and the non-blocking position.
Abstract:
A two-axis satellite antenna mounting and tracking assembly including a universal joint for mounting the antenna to support structure. A pair of linear actuators offset at 90.degree. to each other about the universal joint are operated in full-on/full-off fashion to control the azimuth and elevation orientations of the antenna. Satellite tracking is effected by maximizing received signal strength.
Abstract:
Lateral FET structure is disclosed for bidirectional power switching, including AC application. A notch extends downwardly from a top major surface to separate left and right source regions and left and right channel regions, and direct the drift region current path between the channels around the bottom of the notch. Split gate electrodes in the notch proximate the channels control bidirectional conduction, and are at non-common potentials in the OFF state to increase breakdown voltage. Self-shielding of the gates is also disclosed to further increase OFF state breakdown voltage.