Abstract: A method follow the change in concentration of a redox-active substance, whereby suitable potentials for a reduction process or an oxidation process are applied to the working electrode of a measuring device. The potential of the working electrode is pulsed and measuring phases and relaxation phases are alternately produced, the pulse lengths of measuring phase and relaxation phase being determined in a suitable manner. A rapid relaxation of the concentration gradient is electrochemically forced so that the measurement can be carried out on simple transducer arrays. A device for carrying out the method includes a transducer array in addition to a suitable potentiostat. The transducer array can be formed of a planar metal substrate on which at least one flexible insulator is disposed, the metal surface and the insulator surface being firmly linked. The transducer array can also be formed of silicone-based CMOS structures.

Abstract: In order to follow the change in concentration of a redox-active substance, potential suitable for a reducing process or oxidation process are applied to the working electrode of a measuring device. The potential of the working electrode is pulsed and measuring phases and relaxation phases are alternately produced, the pulse lengths of the measuring phase and relaxation phase being predetermined in a suitable manner. In this manner, a rapid relaxation of the concentration gradient is forced electrochemically so that the measurement can be carried out on simple transducer arrays. The device includes a transducer array in addition to a suitable potentiostat. The transducer array may include a planar metal substrate on which at least one flexible insulator having a firm connection between the metal surface and the insulator surface is located. The array is generated by suitably structuring the substrate.

Abstract: A method for biochemical analysis uses a micro-reaction array with at least two reaction chambers for materials which react together chemically or biochemically. The reaction chambers are smaller than 1 ?l, the reaction chambers are filled together by throughflow, the chemical or biochemical reactions of the substances retained therein then occurs in the individual isolated reaction chambers, thus preventing an interference between the reactions in the individual reaction chambers and the reaction products remain enclosed in the relevant reaction chambers. In the system the planar array has at least two reaction chambers for substances, whereby the reaction chambers are closed with the goal of preventing an exchange of substances.

Abstract: A method follow the change in concentration of a redox-active substance, whereby suitable potentials for a reduction process or an oxidation process are applied to the working electrode of a measuring device. The potential of the working electrode is pulsed and measuring phases and relaxation phases are alternately produced, the pulse lengths of measuring phase and relaxation phase being determined in a suitable manner. A rapid relaxation of the concentration gradient is electrochemically forced so that the measurement can be carried out on simple transducer arrays. A device for carrying out the method includes a transducer array in addition to a suitable potentiostat. The transducer array can be formed of a planar metal substrate on which at least one flexible insulator is disposed, the metal surface and the insulator surface being firmly linked. The transducer array can also be formed of silicone-based CMOS structures.

Abstract: A DNA chip includes a carrier and a microarray of spots containing immobilised catcher molecules which are arranged on the carrier. Each spot contains a microelectrode system for the impedance spectroscopic detection of binding events occurring between the catcher molecules and target molecules of an analyte solution applied to the spots. The microelectrode system has a pair of polarisation electrodes in order to produce an alternating electromagnetic field and a pair of sensor electrodes for measuring a voltage drop in the analyte.

Abstract: In order to follow the change in concentration of a redox-active substance, potential suitable for a reducing process or oxidation process are applied to the working electrode of a measuring device. The potential of the working electrode is pulsed and measuring phases and relaxation phases are alternately produced, the pulse lengths of the measuring phase and relaxation phase being predetermined in a suitable manner. In this manner, a rapid relaxation of the concentration gradient is forced electrochemically so that the measurement can be carried out on simple transducer arrays. The device includes a transducer array in addition to a suitable potentiostat. The transducer array may include a planar metal substrate on which at least one flexible insulator having a firm connection between the metal surface and the insulator surface is located. The array is generated by suitably structuring the substrate.

Abstract: A DNA chip includes a carrier and a microarray of spots containing immobilised catcher molecules which are arranged on the carrier. Each spot contains a microelectrode system for the impedance spectroscopic detection of binding events occurring between the catcher molecules and target molecules of an analyte solution applied to the spots. The microelectrode system has a pair of polarisation electrodes in order to produce an alternating electromagnetic field and a pair of sensor electrodes for measuring a voltage drop in the analyte.

Abstract: Redox (re)cycling is improved in terms of the measurement technique in such a way that the redox potential created by a redox pair is measured on a reference electrode in an electroless manner. A configuration adapted to the method contains an electrode system having at least three electrodes: one working electrode, one counter electrode and one reference electrode. The reference electrode is arranged in such a way that it is adjacent to at least partial areas of the two other electrodes, and preferably, at an equal distance from the partial areas. In terms of redox recycling, the electrode system is suitable, for example, for detecting enzyme-coupled identification reactions, but also for measuring an oxygen partial pressure or hydrogen peroxide.

Abstract: A method for biochemical analysis uses a micro-reaction array with at least two reaction chambers for materials which react together chemically or biochemically. The reaction chambers are smaller than 1 &mgr;l, the reaction chambers are filled together by throughflow, the chemical or biochemical reactions of the substances retained therein then occurs in the individual isolated reaction chambers, thus preventing an interference between the reactions in the individual reaction chambers and the reaction products remain enclosed in the relevant reaction chambers. In the system the planar array has at least two reaction chambers for substances, whereby the reaction chambers are closed with the goal of preventing an exchange of substances.

Abstract: Cold starting includes the steps of directly converting process gas into thermal energy by a catalytic reaction, and utilizing the thermal energy to heat up the fuel cell stack, wherein the process of heating up the fuel cell stack is carried out separately from the operation of the fuel cell facility. Heating elements form separate components in the fuel cell stack, the element being mounted in a predetermined order in the fuel cell stack.

Abstract: The PEM fuel cell has a membrane-electrode assembly with an anode and a cathode and associated bipolar plates. The anode, which forms a hydrogen electrode of the PEM fuel cell, is formed with a substrate of a metal and/or an alloy that is corrosion-resistant within the operational potential range of the hydrogen electrode. That is, the substrate is a good electrical conductor, instead of the poorly conducting carbon powder, and the flow of current within the cell is improved. A catalyst, which is active for the oxidation, is provided at least on the surface of the anode substrate.

Abstract: A fuel cell stack includes at least two stacked fuel cell units which are held together by a material which has sealing and fixing properties. A method for assembling a fuel cell stack is also provided.

Abstract: A fuel cell installation and a method for operating a fuel cell installation with a dynamic power control are provided. The dynamic power control is achieved by additionally connecting at least one subsystem which is kept ready for operation, a starter system and/or a low-voltage unit for nighttime operation and/or an on-board power supply.

Abstract: The fuel cell stack can be electrically cold started by simply applying a voltage to the electrodes of at least one cell, in combination with the introduction of hydrogen into the cathode chamber. The electrodes and the membrane are then rapidly heated electrically without corrosion problems.

Abstract: A method for cleaning a reformer gas in a fuel cell installation includes the step of passing the reformer gas through at least one fuel cell and electrochemically oxidizing CO in the at least one fuel cell to form CO2. A fuel cell installation with an integrated gas cleaning is also provided.

Abstract: A liquid-cooled fuel cell battery and a method for operating such a battery includes reducing the heat capacity of the fuel cell battery at a start time by removing at least some of the cooling liquid from the cooling system when the battery is being switched off to improve the starting performance of the battery.

Abstract: An operating method is described for cold-starting direct methanol fuel cells. After a load has been disconnected (during the preceding operating phase), air is removed from the cathodes by a residual anode gas, and hydrogen is generated at the cathodes by supplying electrical energy. The newly formed hydrogen is then stored. For starting-up, in a short-circuit mode, air is resupplied to the cathodes and hydrogen is supplied to the anodes. After an operating temperature has been reached, the operation is switched over to a methanol mode.

Abstract: A fuel cell battery is described with a heater and an improved cold-start performance, and to a method for cold-starting of a battery of this type. The heater, such as for example a reformer, is started first, and the operating heat from the heater is utilized to heat the fuel cell stack.

Abstract: A fuel cell battery having an improved cold-starting performance and a method for cold-starting a fuel cell battery, use reaction heat of an oxyhydrogen gas reaction in the fuel cell for heating. Reaction gas is simply supplied as required into the reaction chamber during starting, so that an electrode of the fuel cell unit acts as a catalytic burner.

Abstract: A cooling system for a battery of fuel cells that contains at least two fuel cells, each of which comprises a membrane-electrode unit and two collector plates is disclosed. Cooling cards supplied with coolant and that are connected to one another via lines are thereby arranged between the individual fuel cell units.