Abstract: A device for printing a droplet onto a substrate includes: a droplet generating member which is needle-shaped and comprises a receiving portion disposed vertically to receive a solution, and a discharge hole connected to the receiving portion and formed on a bottom of the receiving portion so that the solution can be discharged from the receiving portion; a substrate disposed below the droplet generating member, the substrate includes a target portion to which the droplet discharged from the discharge hole of the droplet generating member is dropped and attached; a voltage applier applying a voltage to the droplet so that the droplet can be dropped onto the target portion of the substrate; a volume measuring unit measuring the volume of the droplet; and a droplet control unit maintaining the volume of the droplet at a predetermined level based on the measured volume of the droplet.

Abstract: Disclosed is an apparatus and method for ejecting droplets using charge concentration and liquid bridge breakup. The droplet ejection apparatus includes a reservoir storing a liquid; a capillary nozzle having a lower end submerged in the liquid stored in the reservoir and an upper end exposed outside the surface of the liquid, the capillary nozzle transferring the liquid to the upper end using capillary force; a potentiostat for applying a voltage to the liquid; a substrate mount on which a substrate is disposed to face the upper end of the capillary nozzle; and a distance adjusting unit for reciprocatingly moving the substrate between first and second positions with respect to the capillary nozzle, wherein the first position denotes a position where a distance between the upper end of the capillary nozzle and the surface of the substrate is less than a effective distance.

Abstract: A fuel cell system includes: a fuel supply unit supplying a fuel; an air supply unit supplying air; a stack including a membrane electrode assembly (MEA) having an air path and a fuel path; a gas-liquid separator connected to an outlet of the fuel path and an outlet of the air path for separating gas-liquid into high-temperature liquid and moisture gas; a mixer mixing the high-temperature liquid separated by the gas-liquid separator and a fuel supplied from the fuel supply unit and connecting the gas-liquid separator and the MEA; a moisture absorbent connected to the gas-liquid separator to absorb condensed liquid in the high-temperature moisture gas; and a heat exchanger to vaporize the liquid absorbed by the moisture absorbent.

Abstract: Disclosed is an apparatus and method for ejecting droplets using charge concentration and liquid bridge breakup. The droplet ejection apparatus includes a reservoir storing a liquid; a capillary nozzle having a lower end submerged in the liquid stored in the reservoir and an upper end exposed outside the surface of the liquid, the capillary nozzle transferring the liquid to the upper end using capillary force; a potentiostat for applying a voltage to the liquid; a substrate mount on which a substrate is disposed to face the upper end of the capillary nozzle; and a distance adjusting unit for reciprocatingly moving the substrate between first and second positions with respect to the capillary nozzle, wherein the first position denotes a position where a distance between the upper end of the capillary nozzle and the surface of the substrate is less than a effective distance.

Abstract: A micro air delivery device for supplying air to a predetermined space, comprises a jet unit for obtaining and delivering outside air; a cover having a discharge orifice for discharging the outside air delivered from the jet unit; and a base unit connected to the jet unit. Since a valve is not employed to regulate the air supply or delivery, the air delivery device is superior in safety, is of simplified construction, and efficient. Furthermore, the air flow can be controlled by varying the electric current or the frequency, and accordingly, an active delivery of the air is possible.

Abstract: Disclosed is an apparatus and method for ejecting droplets using charge concentration and liquid bridge breakup. The droplet ejection apparatus includes a reservoir storing a liquid; a capillary nozzle having a lower end submerged in the liquid stored in the reservoir and an upper end exposed outside the surface of the liquid, the capillary nozzle transferring the liquid to the upper end using capillary force; a potentiostat for applying a voltage to the liquid; a substrate mount on which a substrate is disposed to face the upper end of the capillary nozzle; and a distance adjusting unit for reciprocatingly moving the substrate between first and second positions with respect to the capillary nozzle, wherein the first position denotes a position where a distance between the upper end of the capillary nozzle and the surface of the substrate is less than a effective distance.

Abstract: A fuel cell system, and a method of controlling an operation of a plurality of fuel cells. The fuel cell system controls the operation of the plurality of fuel cells according to a power consumed in a load and the performance of the plurality of fuel cells, thereby increasing a power conversion efficiency of the plurality of fuel cells while preventing considerable performance degradation of the plurality of fuel cells. The fuel cell system includes: a plurality of fuel cells; a control unit controlling an operation of the plurality of fuel cells according to a power consumed in a load and the performance of the plurality of fuel cells; and a converter converting a power output by at least one of the plurality of fuel cells into a power according to the control of the control unit.

Abstract: A fuel cell system includes: a fuel cell stack for generating electrical energy by reacting oxidant and mixed fuel, and for discharging non-reacted fuel, oxidant, moisture, and carbon dioxide; a mixer for preparing the mixed fuel by mixing at least a portion of the non-reacted fuel, oxidant and moisture with concentrated fuel and for supplying the mixed fuel to the fuel cell stack; a fuel supply unit for supplying the concentrated fuel to the mixer; an oxidant supply unit for supplying the oxidant to the fuel cell stack; a first heat exchanger between an outlet of the fuel cell stack and the mixer; and a second heat exchanger between the mixer and an inlet of the fuel cell stack.

Abstract: A fuel cell system and method for driving the same is disclosed. In one embodiment, the fuel cell system includes i) a fuel supply unit, ii) a fuel cell stack in fluid communication with the fuel supply unit, wherein the fuel cell stack has a fuel inlet and a fuel outlet and iii) a bypass pipe configured to transfer fuel received from the fuel supply unit to a fuel outflow pipe connected to the fuel outlet. In one embodiment, the driving method includes i) receiving fuel from a fuel supply unit, ii) transferring the received fuel to a fuel outflow pipe connected to a fuel outlet of a fuel cell stack and iii) discharging non-reacted fuel from a fuel inlet of the fuel cell stack.

Abstract: A liquid fuel cartridge and a direct liquid feed fuel cell system having the liquid fuel cartridge. The direct liquid feed fuel cell system includes: a housing having a cartridge inserting groove and a longitudinal opening in the cartridge inserting groove; a fuel cell located in the housing and composed of cathode and anode electrodes and an electrolyte membrane; a liquid fuel cartridge that contains a liquid fuel, inserted into the cartridge inserting groove, to supply the liquid fuel to the anodes; and a fuel transport unit to transport the liquid fuel from the liquid fuel cartridge to the anodes, wherein the liquid fuel is supplied to the fuel transport unit when the liquid fuel cartridge is rotated in a first direction and the supply of the liquid fuel is disconnected when the liquid fuel cartridge is rotated in an opposite direction.

Abstract: A fuel cell system according to exemplary embodiments of the present invention includes a fuel cell stack that generates electrical energy through the electrochemical reaction of fuel and oxidant, a fuel supply unit for supplying the fuel to the fuel cell stack, and an oxidant supply unit for supplying the oxidant to the fuel cell stack. The fuel supply unit includes a fuel permeation membrane between a space where fuel recovered from the fuel cell stack is positioned and a space where stored fuel is positioned. The fuel cell system enables easy control of the concentration of fuel supplied to the fuel cell stack.

Abstract: A method for controlling the hydrophilic droplet using the electrowetting principle is disclosed. More specifically, the present invention provides a method for increasing the change of the contact angle in the interface that is formed between the hydrophilic droplet and the nonpolar fluid by adding a constant concentration of two-element electrolyte or three-element electrolyte to the hydrophilic droplet; and an apparatus for controlling the droplet having the change of the contact angle and velocity scope increased by the method.

Abstract: A direct liquid feed fuel cell includes a membrane electrode assembly including a plurality of unit cells composed of an electrolyte membrane, and a plurality of anodes and cathodes formed on opposing surfaces of the electrolyte membrane; a current collection plate including a plurality of first current collecting portions correspondingly coupled with the anodes; a diffusion plate receiving a liquid fuel supplied from an inlet formed at a side thereof; a liquid fuel tank supplying the liquid fuel to the diffusion plate through the inlet; a plurality of second current collecting portions correspondingly coupled with the cathodes; a porous plate, arranged on the second current collecting portions, and communicating with air; and a conductive portion coupling the first and second current collecting portions to form an electrical circuit of the unit cells.

Abstract: A fuel delivery apparatus for a direct liquid feed fuel cell is provided. The fuel delivery apparatus includes a plate stack formed by a one or more double-sided plates positioned between opposing end plates. Both sides of the one or more double-sided plates, and the interior side of each end plate, may include one or more microchannels that extend between, and link, an inlet port with an outlet port. The length of the microchannels is chosen to be less than the height of a predetermined meniscus so that liquid fuel propelled by capillary force forms a meniscus that stands proximate the interface between the ends of the microchannels and the outlet port. A heater may be located at the upper ends of the microchannels around the plate stack, to vaporize the liquid fuel at the meniscus.

Abstract: A fuel cell system and a fuel cell power managing method in which the fuel cell system controls a current output of a fuel cell by adjusting a target voltage value of the fuel cell according to a difference between a current value of the fuel cell and a target constant current value. By doing so, the fuel cell system may allow the fuel cell to stably and constantly output a constant current.

Abstract: A direct methanol fuel cell (DMFC) system including: a separator receiving a gas-liquid mixture discharged from a stack and separating the mixture to gas and a liquid; a methanol cartridge storing high concentration methanol; and a fuel mixer for methanol dilution. The separator and the fuel mixer are separate structures, each including an agitator for stirring a liquid. The agitators can be on the same rotation axis.

Abstract: In a fuel cell system including a fuel cartridge and a fuel supply module, the fuel cartridge includes at least two ports, wherein a first port from among the at least two ports is a fuel inlet port and a second port from among the at least two ports is a fuel outlet port. The fuel cartridge may also include a fuel pouch or the fuel cartridge itself may be the fuel pouch. The fuel supply module may include a fuel circulation structure that circulates the fuel before the fuel is supplied to the stack. The fuel cell system may be equipped with an electronic apparatus and serve as a source of power.

Abstract: A fuel supply device for direct methanol fuel cells. The fuel supply device for direct methanol fuel cells includes a fuel tank to store a liquid fuel, a cavity plate to store the liquid fuel transferred from the fuel tank, a thin film type active pump welded on the bottom of the cavity plate to bring about a movement of the cavity plate, and a nozzle plate disposed on the cavity plate to eject the liquid fuel. Accordingly, it is possible to actively control a liquid fuel in a needed amount and supply it to a fuel cell in accordance with a use mode of an electronic device and effectively remove by-products of the fuel cell, thereby improving the efficiency of the fuel cell.

Abstract: Provided is a droplet dispensing device having a nonconductive capillary nozzle. The droplet dispensing device comprises: a nonconductive capillary nozzle disposed in a downward position; a pump connected with the nonconductive capillary nozzle through a hermetically sealed fluid tube and generating a negative pressure to decrease the influence of gravity on a solution within the nonconductive capillary nozzle and the fluid tube; and an open circuit voltage supplier applying a voltage to the solution. The droplet dispensing device supplies the solution by capillary force to regularly maintain the shape of a droplet surface in the tip of the nonconductive capillary nozzle without using a separate driving device.

Abstract: A method for controlling the hydrophilic droplet using the electrowetting principle is disclosed. More specifically, the present invention provides a method for increasing the change of the contact angle in the interface that is formed between the hydrophilic droplet and the nonpolar fluid by adding a constant concentration of two-element electrolyte or three-element electrolyte to the hydrophilic droplet; and an apparatus for controlling the droplet having the change of the contact angle and velocity scope increased by the method.