Yuanqing Guo received his Ph.D. from Wuhan in early 2001. His thesis was concerned with MIR-LMR spectra of NO and NO₂. He came to Kiel in July 2001 and brought our FIR-LMR spectrometer back into business. Another project Yuanqing has been working on was cavity-ring-down spectroscopy of Si containing radicals and the kinetics of SiH₂ reactions. He developed a new quantitative method to include the laser bandwidth effects in the analysis of simultaneous chemical kinetics and ringdown decay profiles.