A method for fabricating a quantum dot infrared photodetector by using molecular beam epitaxy is provided. The most often used calcium salts of the folates have a low solubility in water and form almost insoluble degradation products. A roughly estimated number of pills are placed upon the tray and illuminated by the light source, whereafter a digital image of the pills is produced by the camera and sent via an interface to the PC. The system also includes an external reduction stage located outside the transmission housing and driven by the first motor shaft to rotate the inputoutput shaft. The present invention also provides two methods for manufacture of continuous helical baffles, which ensure the concentricity of the tube bundle holes on each continuous helical baffle so as to facilitate installation of heat exchange tube bundles. With the aid of the adsorption capability of at least partially uncombusted hydrocarbons of one of the catalytic converters a diagnosing forecast about the NO oxidization of the catalytic converters is derived, whereby the at least partially uncombusted hydrocarbons are introduced into the exhaust gas duct at least partially in front of the catalytic converter.