Showing papers by "Wolfram Wersing published in 1993"

Ultrasound array having trapezoidal oscillator elements and a method and apparatus for the manufacture thereof

Abstract: An ultrasound array has a number of oscillator elements arranged side-by-side, each oscillator element having a trapezoidal cross-section. The oscillator elements are separated from each other by incisions having non-parallel walls, which are co-planar with surfaces of the piezoelectric material comprising the oscillator element. The incisions terminate in a damping member, to which all of the oscillator elements are attached. The incisions are produced with an excimer laser whose laser beam is focused onto a prepared layered material, with the incisions proceeding along a line.

Hochtemperatur-brennstoffzellen-stapel und verfahren zu seiner herstellung

Abstract: Bei der Fugung eines Hochtemperatur-Brennstoffzellen-Stapels tritt grundsatzlich das Problem einer grosflachigen Kontaktierung der Grenzflachen Elektrode - bipolare Platte auf. Infolge der Restwelligkeit von Elektrolyt und darauf aufgebrachten Elektroden und der daraus resultierenden Ausbildung von schlecht elektrisch leitenden Interdiffusionsschichten an Kontaktlucken, sinkt infolge des daraus resultierenden Anstiegs des Innenwiderstandes des Stapels der Gesamtwirkungsgrad. Zur Behebung dieses Mangels ist es erfindungsgemas vorgesehen, das bei einem Hochtemperarturbrennstoffzellenstapel (2) mindestens eine Funkionsschicht (20, 22) vorgesehen ist, die zwischen Elektrode (10, 12) und bipolarer Platte (16, 18) angeordnet und im Bereich der Betriebstemperatur des Stapels (2) elektronisch leitend und leicht verformbar ist. Die Erfindung ist bei allen Hochtemperaturbrennstoffzellensstapel einsetzbar.

Integrated ceramic high-temperature fuel cell

Abstract: It is proposed for an integrated high-temperature fuel cell (SOFC [solid oxide fuel cell]) initially to produce at least one planar base body, comprising three mutually adjacent functional layers of the fuel cell, from green sheets, to pile up the latter, if desired with further functional layers, to form a stack and, finally, to press and sinter the latter to form the fuel cell stack. The composite (laminated) bodies, which are presintered if desired, have a higher stability than the corresponding individual layers, with the result that the latter can be made thinner. A special sealing process makes it possible for the fuel cell produced in this way to operate reliably with a high efficiency.

Electrolyte lamina for planar high-temperature fuel cells, and method for the preparation thereof

Abstract: For a planar high-temperature fuel cell, an electrolyte lamina having a ceramic multilayer (sandwich) structure is proposed, which comprises a mechanically stable self-supporting layer of high ionic conductivity and an electrolyte layer which in comparison is considerably thinner and is made of yttrium-stabilised zirconium oxide or alternatively only one mechanically stable layer made of tetragonal partly stabilised zirconium oxide. By virtue of the ionic conductivity being improved overall, the electrolyte lamina can be employed at an operating temperature from 700 DEG C.

High-temperature fuel cell stack and process for producing it

Abstract: In joining a high-temperature fuel cell stack there arises the basic problem of the contact over a large area of the electrode-dipole plate boundary areas. Owing to the residual ripple of the electrolyte and the electrodes fitted thereto and the resultant formation of poorly electrically conductive inter-diffusion layers at contact gaps, the overall efficiency falls owing to the resultant rise in the internal resistance of the stack. To remedy this problem the invention provides for the arrangement in a high-temperature fuel cell stack (2) of at least one functional layer (20, 22) between the electrode (10, 12) and the dipole plate (16, 18), said functional layer being electronically conductive and easily deformable at the operating temperature of the stack (2). The invention is applicable to all high-temperature fuel cell stacks.

Capacitor arrangement and production method therefor

Abstract: It is proposed to arranged ferroelectric capacitors vertically with respect to a monocrystalline substrate (1). Optimal ferroelectric layer (3) production is achieved by epitaxy over at least one buffer layer (2) at optimally high deposition temperatures. After structuring of the epitaxial ferroelectric layer, the electrodes (6) are applied laterally. By combination with a read and write circuit integrated in the substrate (1), the capacitor arrangement can be used for producing large-scale integrated semiconductor memory modules.