A third promising approach to coherent DNP methods utilizes relatively low µw power and either magnetic field sweeps or frequency swept (chirped) µw pulses to implement the integrated solid effect (ISE) , the stretched solid effect (SSE) , and the adiabatic solid effect (ASE) . The ISE was initially performed by adiabatically sweeping the magnetic field through both SE matching conditions , coherently transferring the electron polarization to the surrounding nuclear spins. It was then shown that ISE can be more readily performed with frequency chirped pulses using an arbitrary waveform generator (AWG) while keeping the magnetic field constant . Subsequently, the SSE 27 and ASE were carried out using narrower µw chirped pulses and it was observed that they yielded larger enhancements than the ISE.