[Theoretical analysis of the residual amplitude modulation of frequency modulation strong absorption spectroscopy].

The application of frequency modulation (FM) spectroscopy technology in the trace gas detection is greatly restricted by the residual amplitude modulation (RAM) which induced by the birefringence of the electro-optic modulator (EOM) and the misaligned linear polarization direction of laser to the EOM. Based on the interaction between the laser field and crystal, a line-shape expression of the FM spectroscopy with RAM is obtained. The angle between the polarization direction of input light and the principle axis of EOM, theta, the phase difference between the two principle axes of electro-optic crystal, delta phi, and the modulation index FM, beta, are the major factors to influence the lineshape.

Clinical predictors for progression of nonintervened nonculprit coronary lesions despite low-density lipoprotein cholesterol less than 1.8 mmol/l after successful stent implantation.

Objective: Despite achieving very low levels of low-density lipoprotein cholesterol (LDL-C), many patients continue to show disease progression. We sought to characterize the clinical factors that correlate with nonculprit lesion plaque progression in patients with LDL-C level less than 1.8 mmol/l.