Abstract: A method for testing and adjusting catalytic exhaust gas emission control systems of internal combustion engines, in which the fuel-air-ratio is regulated by means of a .lambda.-probe (control-probe) arranged in the exhaust gas stream upstream of the catalyst, whereby the exhaust gas stream is measured downstream of the catalyst by means of a further .lambda.-probe (test-probe). The voltage average value and amplitude magnitude of the signal produced by the test-probe are determined and serve for adjusting the operating point of the control system and for the recognition of the catalyst efficiency.

Abstract: A sheet material useful for preparing high strength composite structures, especially in the field of light weight construction material, comprises a layer (A) of a high strength fibrous material impregnated and/or coated with a curable synthetic resin in the B-stage and a layer (B) of a polyamide polymer or another polymer having similar properties and being compatible with the curable synthetic resin of layer (A), which layer (B) is partially or completely bound to or embedded in layer (A).