A comparative study on essential oils from the leaves and stems of Vietnamese Kunth.

Kunth is widely known as potential herbal medicine, although it is an invasive alien species in Southeast Asia. In this study, the essential oils from leaves and stems of were extracted by hydrodistillation method, and the chemical profiles of essential oils were then analysed by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS). It was found that there were similarities and differences in chemical compositions and their percentage between the essential oils obtained from these two parts.

A New Simple Analytical Method for a Highly Accurate Determination of the Optical Parameters of a Slab from Transmittance Data.

To date, determining with high accuracy the optical parameters (extinction coefficient and refractive index ) of a slab from the sole transmittance data requires an inverse method based on numerical iteration procedures. In this paper, we propose a new inverse analytical method of extracting (, ) without numerical iterative processes. The high accuracy of this new inverse method is assessed, and as an application example, the optical parameters of CaF and Si substrates are determined in the IR spectral range of 4-8 µm.