Abstract: A system and method for controlling or otherwise effectively managing fuel mixing and/or transport in a fuel cell device comprises inter alia a fuel mixing chamber (100), a pure fuel inlet line (110), a bubbling line (120) and a dilute fuel outlet line (130). Disclosed features and specifications may be variously adapted or optionally modified to control or otherwise optimize the rate and/or uniformity of fuel mixing in any fuel cell system. Exemplary embodiments of the present invention may be readily integrated with other existing fuel cell technologies for the improvement of device package form factors, weights and other manufacturing and/or device performance metrics.

Abstract: Switches (306) are used to connect stacks of fuel cells (302, 304) in series or in parallel depending on the load to keep total cell voltage below a maximum input voltage requirement. The cells (302, 304) are coupled in parallel under low power conditions, and the cells are coupled in series under high power conditions to provide a more efficient system (500).

Abstract: An exemplary system and method for manufacturing micropump systems having integrated piezoresistive sensors is disclosed as including inter alia: a substrate, an inlet channel, an outlet channel, a pumping cavity, a first valve for permitting fluid flow from the inlet channel to the pumping cavity and restricting backflow of purged fluid from the pumping cavity to the inlet channel; a second valve for permitting fluid flow from the pumping cavity to an outlet channel and restricting backflow of purged fluid from the outlet channel to the pumping cavity; a pump actuator element; a pressure sensing cavity surface capable of at least partial mechanical deformation; a plurality of piezoresistors disposed within the sensing cavity; a plurality of contact pads; a plurality of conductive pathways connecting the piezoresistors and the contact pads; and a substantially monolithic device package, wherein the sensing cavity is substantially contained within the micropump device package.

Abstract: A system and method for controlling or otherwise effectively managing cell voltage degradation in the operation of a fuel cell device comprises inter alia a fuel cell (110) in parallel electrical connection with a secondary power source (145) and an automated controller (155) for switching between power supplied from the fuel cell (100) and the secondary power source (145). Disclosed features and specifications may be variously adapted or optionally modified to control or otherwise optimize the rate of cell voltage degradation in any fuel cell system. Exemplary embodiments of the present invention may be readily integrated with other existing fuel cell technologies for the improvement of device package form factors, weights and other manufacturing and/or device performance metrics.

Abstract: A system and method for controlling or otherwise effectively parameterizing the delivery of fuel to a fuel cell device comprises a fuel pump (330), a mixing chamber (310), a fuel concentration sensor (350), a control device (360), a pump driver (370) and a pulse generator (380). Various features and parameters of the present invention may be suitably adapted to optimize the fuel transport function for any particular fuel cell design. The present invention provides inter alia improved control of delivery of methanol to a DMFC fuel solution.

Abstract: An exemplary device and method for microfluidic transport is disclosed as providing inter alia a valve membrane sheet (400), an inlet channel (140) and an outlet channel (150). The valve membrane sheet effectively confines transport of fluid from the inlet channel to the outlet channel where fluid may be purged. The valve membrane sheet also generally provides means for preventing or otherwise substantially decreasing the incidence of purged fluid re-entering the inlet channel. Accordingly, the reduction of backflow generally tends to enhance overall pumping performance and efficiency. Disclosed features and specifications may be variously controlled, adapted or otherwise optionally modified to improve micropump operation in any microfluidic application.

Abstract: An exemplary method for making a micropump device is disclosed as providing inter alia a substrate (300), an inlet opening (310), and outlet opening (340), a pump chamber (370) and flapper valves (350, 360). The fluid inlet channel (310) is generally configured to flow a fluid through/around the inlet opening flapper valve (350). The outlet opening flapper valve (360) generally provides means for preventing or otherwise decreasing the incidence of outlet fluid re-entering either the pumping cavity (370) and/or the fluid inlet channel (310). Accordingly, the reduction of backflow generally tends to enhance overall pumping efficiency. Disclosed features and specifications may be variously controlled, adapted or otherwise optionally modified to improve micropump operation in any microfluidic application.

Abstract: An exemplary method for making a micropump device is disclosed as providing inter alia a substrate (300), an inlet opening (310), and outlet opening (340), a pump chamber (370) and flapper valves (350, 360). The fluid inlet channel (310) is generally configured to flow a fluid through/around the inlet opening flapper valve (350). The outlet opening flapper valve (360) generally provides means for preventing or otherwise decreasing the incidence of outlet fluid re-entering either the pumping cavity (370) and/or the fluid inlet channel (310). Accordingly, the reduction of backflow generally tends to enhance overall pumping efficiency. Disclosed features and specifications may be variously controlled, adapted or otherwise optionally modified to improve micropump operation in any microfluidic application.

Abstract: Switches (306) are used to connect stacks of fuel cells (302, 304) in series or in parallel depending on the load to keep total cell voltage below a maximum input voltage requirement. The cells (302, 304) are coupled in parallel under low power conditions, and the cells are coupled in series under high power conditions to provide a more efficient system (500).

Abstract: A fuel delivery system for a fuel cell (400) includes a substrate (404) having a cavity (402) formed therein, an o-ring (408) embedded within the cavity, and a detachable tube (410) inserted though and retained within the o-ring. The tube (408), when inserted through the o-ring (408), forces the o-ring to expand and fill the cavity (402) thereby forming a liquid tight seal for the transfer of liquid (414) to a fuel cell chamber (416).

Abstract: A fuel cell system is protected by monitoring at least one fuel cell parameter, comparing the parameter to a preset level, and disconnecting or reconnecting a main load in response to the fuel cell parameter. For example, a fuel cell system (300) is provided with a protection circuit (304, 308) that prevents operation of the fuel cells in the negative dP/dI region. System (300) includes a stack of fuel cells (302) connected in series and coupled to a main load (310). A controller (304) provides a control signal (314) based on the individual fuel cell voltage levels falling above or below a preset level. Control signal (314)is used to control a load switch (308)coupled between the stack of fuel cells (302) and the main load (310). The load switch (308) disconnects the main load (310) in order to prevent operation of the fuel cell cells in the negative dP/dI region.

Abstract: A field emission cathode is provided which includes a substrate and a conductive layer desposed adjacent the substrate. An electrically resistive pillar is disposed adjacent the conductive layer, the resistive pillar having a substantially flat surface spaced from and substantially parallel to the substrate. A layer of diamond is disposed adjacent the surface of the resistive pillar.

Abstract: Before submitting a sample, including a first material layered upon a substrate, to an ion milling process, whereby a second material is sputtered onto the surface of the first material and the sample is then submitted to an etching process, an irregularity is formed on the surface of the first material. The overall process results in the formation of cones, or micro-tip structures, which may then be layered with a layer of low work function material, such as amorphous diamond. The irregularity in the surface of the first material may be formed by polishing, sandblasting, photolithography, or mechanical means such as scratching.

Abstract: A field emission cathode for use in flat panel displays is described including a layer of conductive material and a layer of amorphic diamond film, functioning as a low effective work-function material, deposited over the conductive material to form emission sites. The emission sites each contain at least two sub-regions having differing electron affinities. Use of the cathode to form a computer screen is also described along with the use of the cathode to form a fluorescent light source.

Abstract: A field emission device (200) includes a cathode plate (110) having a back plate (112) made from glass and an anode plate (120) having a transparent substrate (122) also made from glass. A first charge control electrode (152) is affixed to a distal surface (148) of back plate (112), and a second charge control electrode (158) is affixed t0 the periphery of transparent substrate (122). A ballast resistor (114) is disposed on a proximate surface (155) of back plate (112). A method for operating told omission device (200) includes the stop of controlling a potential applied to first charge control electrode (152) in a manner sufficient to control the conductivity of ballast resistor (114) and provide an electron current (138) that is constant. The method further includes the step of controlling a potential applied to second charge control electrode (158) in a manner sufficient to prevent arcing due to wild up or charge within transparent substrate (122).

Abstract: A vacuum microelectronic device (10) is formed by applying a conditioning voltage or field between the anode (17) and the electron emitters (13). The conditioning field has a value sufficient to move some of the electron emitters (13) in a direction toward the conditioning field. Some of the electron emitters (13) remain in that position after removing the conditioning field.

Abstract: A field emission display (100) includes a cathode assembly (102), an anode plate (104), and a spacer (108), which extends between the cathode assembly (102) and the anode plate (104). The spacer (108) is comprised of a spacer material having a dielectric constant less than 100. A discharging period neutralizes positive electrical charge (244) and renders the spacer (108) invisible to a viewer of the field emission display (100). Operating a field emission display (100) to render a spacer (108) invisible by providing a cathode, assembly (102), an anode plate (104), and a spacer (108) comprised of a spacer material with a dielectric constant less than 100 and neutralizing positive electrical charge (244) on spacer (108).

Abstract: A method for improving life of a field emission display (100), which has a plurality of electron emitters (118) and an anode (124), includes the steps of causing plurality of electron emitters (118) to emit electrons, applying a first anode voltage to anode (124), thereafter applying a second anode voltage to anode (124), and thereafter applying a third anode voltage to anode (124). The first anode voltage and the second anode voltage are selected to cause electrons emitted by plurality of electron emitters (118) to be attracted toward anode (124). The third anode voltage is selected to cause electrons emitted by plurality of electron emitters (118) to not be attracted toward anode (124). Furthermore, the second anode voltage is selected to be less than the first anode voltage.

Abstract: A field emission display (100) includes an electron emitter structure (105) designed to emit an emission current (134), a phosphor (126) disposed to receive at an electron-receiving surface (127) emission current (134), and a multi-layered barrier structure (125) disposed on electron-receiving surface (127) of phosphor (126). Multi-layered barrier structure (125) of the preferred embodiment includes an aluminum layer (128) disposed on electron-receiving surface (127) of phosphor (126) and a carbon layer (129) disposed on aluminum layer (128).

Abstract: Before submitting a sample, including a first material layered upon a substrate, to an ion milling process, whereby a second material is sputtered onto the surface of the first material and the sample is then submitted to an etching process, an irregularity is formed on the surface of the first material. The overall process results in the formation of cones, or micro-tip structures, which may then be layered with a layer of low work function material, such as amorphous diamond. The irregularity in the surface of the first material may be formed by polishing, sandblasting, photolithography, or mechanical means such as scratching.