Fabrication and vibration characterization of curcumin extracted from turmeric (Curcuma longa) rhizomes of the northern Vietnam.

In this report, we present the research results on using the conventional method and microwave technology to extract curcuminoid from turmeric roots originated in different regions of Northern Vietnam. This method is simple, yet economical, non-toxic and still able to achieve high extraction performance to get curcuminoid from turmeric roots. The detailed results on the Raman vibration spectra combined with X-ray powder diffraction and high-performance liquid chromatography/mass spectrometry allowed the evaluation of each batch of curcumin crystalline powder sample received, under the conditions of applied fabrication technology.

Experimental Determination of the Fluorescence Quantum Yield of Semiconductor Nanocrystals.

Many studies have considered the luminescence of colloidal II-VI nanocrystals, both in solution at a collective scale and at an individual scale by confocal microscopy. The quantum yield is an important figure of merit for the optical quality of a fluorophore. We detail here a simple method to determine the quantum yield of nanocrystals in solution as a function of the absorption.

Preparation and spectroscopic investigation of CdS/CdSe/CdS quantum-dot quantum-well heterostructures.

CdS/CdSe/CdS quantum-dot quantum-well heterostructures with the different thicknesses of CdSe well layers were synthesized by using the colloidal chemical method. The absorption, photoluminescence and Raman scattering spectra of CdS cores, and CdS/CdSe, CdS/CdSe/CdS structures were investigated. A comparative study of their optical properties confirmed the formation of CdSe well and exterior CdS shell.