Localized vibrational modes of carbon-hydrogen complexes in metalorganic chemical vapor deposition grown GaN on sapphire were studied using a Fourier-transform infrared spectroscopy technique. Three distinctive localized vibrational modes were observed around 2850, 2922, and 2959 cm for undoped, Si-, and Mg-doped samples. These peaks are related to CH, CH2, and CH3 defect complexes, respectivel...

We report on a distance control system for low-temperature scanning near-field optical microscopy, based on quartz tuning fork as shear force sensor. By means of a particular tuning fork-optical fiber configuration, the sensor is electrically dithered by an applied alternate voltage, without any supplementary driving piezo, as done so far. The sensitivity in the approach direction is 0.2nm, and...

This study uses 35 pesticides spiked in spinach extracts at the 50 ppb level to find the optimal AMDIS deconvolution settings. Additional advantages of using deconvolution versus MSD ChemStation, to find more compounds in an extract are also discussed. The detectability of compounds in a complex matrix is significantly improved with deconvolution. This can also be viewed as better or increased ...

benign paroxysmal positional vertigo (bppv) is a condition that indicates a benign inner ear disorder. it is generally believed that bppv is due to the dislodged otoconial particles from otolith organs and unusual collection of them within any of semicircular canals or even in all three semicircular canals. although the typical features of nystagmus in bppv have been well-studied, very few stud...