An improved thermocouple assembly for providing a temperature measurement is provided. The method may comprise the steps of measuring a value of an engine parameter; adjusting the pressure of the exhaust manifold responsive to the measured engine parameter value; actuating the at least one exhaust valve; and adjusting a pressure gradient across the turbocharger. A slurry of finely divided ceramic particles is flowed through nozzles and formed into droplets under the influence of vibration. The fixing ring hitches the outer side of each heat-dissipating fin, and the fixing ring is formed with a plurality of positioning folded plates along an inner ring edge thereof, so as to fix the extended folded plate and keep any two neighboring heat-dissipating fins in a unit pitch distance.