Abstract: In the memory cell arrangement, each memory cell consists of a field-effect transistor comprising a gate dielectric (14) which contains at least one ferroelectric layer (142). Depending on the sign of the remanent polarization of the ferroelectric layer (142), the field-effect transistor exhibits one of two different threshold voltages which have the same sign and which are allocated to the logic states "0" and "1". Information is written in by repolarizing the ferroelectric layer (142), information items are read by applying a voltage to the gate electrode of the field-effect transistor, the voltage being between the two threshold voltages.

Abstract: A method for producing a superconducting layer of YBa.sub.2 CU.sub.3 O.sub.7 on a sapphire substrate utilizes the steps of epitaxially growing an intermediate layer that at least contains a yttrium-stabilized zirconium oxide layer directly on the substrate, and then epitaxially growing a superconducting layer on the intermediate layer. In one embodiment, the step of growing the intermediate layer grows two sub-layers, with the first sub-layer being a yttrium-stabilized zirconium oxide layer and a second sub-layer being a yttrium oxide layer applied onto the first sub-layer.

Abstract: A composite ultrasound transducer (array) contains piezoelectric ceramic transducer elements which radiate substantially in the longitudinal direction, and are embedded in a polymer matrix. The transducer elements have such a geometrical structure, and are arranged relative to each other, so that the development of oscillation modes perpendicular to the longitudinal direction of the transducer elements is suppressed. A method for manufacturing the composite ultrasound transducer includes the steps of filling a plastic form, having a "negative" of the desired shape of the transducer elements, with ceramic slurry, and pyrolyzing the plastic form after the slurry dries therein. The resulting voids between the hardened ceramic elements are filled with polymer to create the overall composite transducer.

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.

Abstract: The invention is directed to a piezo-electric transducer having electrodes that adhere well both to ceramic as well as to plastics and that are composed of intrinsically conductive plastic. The invention is also directed to a method for the manufacture thereof. A conductive polymer layer is produced on the surface of a piezo-ceramic component by chemical or anodic oxidation of a monomer. The monomers are selected from the class of 5-member heterocycles containing sulfur or nitrogen as heteroatom, or aniline, azuline, or derivatives of the said compounds. The components provided with the economical electrodes can be advantageously composed to form sandwich-like transducers having plastic intermediate layers that exhibit good electro-acoustical properties.

Abstract: A method for working an oxide material, and preferably a ceramic oxide material, with a laser emission of an excimer laser and without the creation of damage layers includes pulsing the laser emission to be impinged on the material to be worked.

Abstract: The invention provides an electrode for piezoelectric composites having high acoustic attenuation. The electrode is composed of a first layer having high elasticity and lower conductivity and of a second layer lying thereabove that has higher conductivity. The invention also provides a method for the manufacture thereof. The first layer is an intrinsically conductive plastic directly deposited on the ceramic whose polymerization is initiated by chemical or anodic oxidation of the corresponding monomers. The second layer is fashioned of adequately conductive metal and is preferably first sputtered on or vapor-deposited in a thinner layer and is then subsequently electrolytically reinforced. Piezoelectric composites that exhibit high acoustic attenation and, thus, prevent an acoustic crosstalk between the individual transducer elements can be manufactured from piezoelectric ceramic lamina or foils provided with such electrodes.

Abstract: A method for manufacturing piezo-electric ceramic materials having predetermined acoustic impedance, wherein internal cavities are generated by a photolithographic process, utilizing a foil stack of green ceramic foils.

Abstract: A piezoelectric ceramic powder is, together with a binder, processed to a granulate. This granulate is mixed with a pearl polymer to a mixture. The mixture is pressed to a suitable shape, and then in a first firing step the binder and the pearl polymer are fired out. Preferably the first firing process is followed by a second firing step for sintering. Thereafter mechanical fabrication may take place, to give the end product its shape. The firing out of the pearl polymer results in a porous piezoelectric ceramic, with which, when used in an ultrasonic transducer, a high transducer effectiveness, sharp ultrasonic pulses with little edge radiation as well as a good electric and acoustic adaptation can be achieved.

Abstract: A material is disclosed for use as an adaptation layer in ultrasonic transducer units of the type which have a piezo-ceramic transducer. The material is porous, and the acoustic impedance of the material can be adjusted (in one embodiment, to 12.times.10.sup.6 kg/cm.sup.2 s) by adjusting the porosity of the material. In preferred embodiments, the material is piezo-electric and may have a porosity gradient.

Abstract: A method for the manufacture of a linear or annular ultrasonics antenna array for the megahertz range, which consists in providing a laminate of alternating layers of unsintered ceramic and spacing layers, the spacing layers being composed of a filler material which is heat fugitive at the sintering temperature of the ceramic, the spacing material also including refractory grains distributed therein of a size which corresponds to the spacing desired between the ceramic layers, sintering the laminate to thereby liberate the filler material and leave voids between the refractory grains, impregnating the resulting laminate with a polymerizable resin to bond the sintered ceramic layers together, and separating the resulting laminate into individual transducer elements.

Abstract: An apparatus for contact-free measurement of electrical charge images of the type generated on a storage plate as transmission images by means of electro-radiographic recording methods has a matrix of dynamically functioning probes, such as Kelvin probes, for scanning the effect of the electrostatic induction caused by the image on the storage plate, the outputs of the probes being amplified and supplied to a display device such as a picture screen. The individual probes of the matrix are electrically conductive elements and a mechanical oscillation is generated between the charge image and the probes in the field to be measured either by oscillating the probes or by oscillating the storage plate. The charge amounts electrostatically induced in the probes are tapped as the image signals.