Abstract: The invention relates to a sealing for the gas-tight connection of two elements of a fuel cell stack comprising an electrically non-conducting spacer component and at least one solder component solid or viscous over its entire extension at the operating temperature of the fuel cell stack and coupling the spacer component to at least one of the elements to be connected of the fuel cell stack in a gas-tight manner. According to the invention it is envisaged that the spacer component is formed of a ceramic material. The invention further relates to a fuel cell stack in which, according to the invention, it is envisaged that a distribution of forces compressing the fuel cell stack in the axial direction is directly transmitted to at least one of the elements to be connected by the spacer component. The invention further relates to production methods for seals and fuel cell stacks.

Abstract: The current invention involves a process for microstructuring surfaces of oriented polymeric substrates using laser radiation having an intensity which is spatially modulated in a predetermined periodic manner. The process is especially useful for microstructuring the surfaces of textile products and films.

Abstract: A tunable laser oscillator, comprises a laser medium, an optical resonator, a wavelength selective element for adjusting the wavelength of a laser beam, and optical means for broadening the radiation in the resonator. The laser beam is decoupled from the resonator by means of an optical element after having passed the broadening means and prior to passing again through the laser medium. The laser beam is decoupled from the resonator such that its direction is independent of the beam wavelength.

Abstract: The present invention relates to a method and an apparatus for gerating pulsed laser radiation which contains components at several freely selectable wavelengths. Multi-wavelength emission is synchronized in time, propagates in a precise spatial overlap and has the same beam parameters on a common propagation direction. A preferred embodiment of an apparatus for a such method is a low pressure CO.sub.2 laser gas discharge in conjunction with a multi-wavelength resonator including a Q switch.

Abstract: A tunable laser oscillator with a broadband emitting and thereby wavelength tunable laser medium. An optical resonator is provided for setting the wavelength of the laser radiation. Following the resonator is a device for spectral filtering and for producing a spectrally purer emitted laser radiation. An aperture is mounted in the path of the radiation following that device. The mechanism used for setting the wavelength of the laser radiation also forms the device for spectral filtering and for producing the spectrally purer emitted laser radiation. An optical arrangement is provided for feeding back the radiation leaving the resonator onto the joint mechanism and device.