Search

To study the identification mechanism of microplastics in agricultural environmental media by molecular spectroscopy, two typical media, soil and fishmeal, were selected for this study. Three common microplastics, PE, PP, and PS, were used as research objects. Near-infrared (NIR) and mid-infrared (MIR) spectroscopy combined with chemometric methods were used to explore microplastics' identification and analysis effects in different agricultural media and reveal their identification mechanisms. PCA analysis revealed that different soil types would affect the identification results of microplastics. PLS-DA discriminant analysis showed that the accuracy of NIR spectroscopy technology in identifying microplastics in different types of soil decreased in the order of sand > loam > clay. In contrast, the rule of MIR spectroscopy technology was the opposite. The sensitivity and specificity of the three microplastics in the NIR model of sand and the infrared spectroscopy model of fishmeal reached 1.000. NIR spectroscopy technology is suitable for identifying microplastics in soil, while infrared spectroscopy technology is more suitable for identifying microplastics in fish meal. Furthermore, based on the VIP values of each wavelength point in the spectrum, the characteristic bands that have essential contributions to identifying microplastics in soil were screened out. The NIR spectra of 4500–4300 cm − 1 , 4300–3900 cm − 1 and 7100–5800 cm − 1 are the most essential characteristic bands for identifying microplastics in clay, loam, and sand, respectively. The MIR of 3000–2900 cm − 1 and 700–650 cm − 1 were the most essential characteristic bands for identifying microplastics in soils, and the overlap of the characteristic spectra of the three soils reached 59.45%. The NIR spectra of 6050–5600 cm − 1 , 4700–4000 cm − 1 and the MIR spectra of 2300–1900 cm − 1 and 800–400 cm − 1 are the most essential characteristic bands for the identifying microplastics in fishmeal. This study provides a more suitable technical "solution" for identifying microplastics in environmental media, which is of great significance for improving the accuracy of molecular spectroscopic identification in environmental media and clarifying the interaction between microplastics and environmental media. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) CuO nanoplatelets were synthesized in the presence of ionic liquids under the mild hydrothermal conditions at 140°C by self-assembly. The thickness of CuO nanoplatelets was about 35 nm prepared in 1-butyl-3-methylimidazolium chloride. XRD, FESEM, and TEM were used to characterize the structure features of the products. FTIR spectra and TG curves confirmed the adsorption of ionic liquids on the surface of CuO nanoplatelets. In addition, UV-visible absorption spectra were employed to estimate the band gap energies of the CuO nanoplatelets as nanosized semiconductors. It was demonstrated that the ionic liquids could act as a cosolvent, soft template agent and modifiers. [ABSTRACT FROM AUTHOR]

Abstract: Yb3Al5O12 single crystal has been grown by Czochralski (CZ) method. The absorption spectrum was investigated at low temperature and the electronic energy levels for 2F5/2 multiplet of Yb3+ in YbAG was proposed. The up-conversion emission of the crystal under 940nm diode pumping and the X-ray excited luminescence (XEL) features of the crystal were also studied. [Copyright &y& Elsevier]

Abstract: Yb: YAlO3 (YAP) (15at%) and Yb: Y3Al5O12 (YAG)(15at%) have been grown using the Czochralski method. Their absorption and fluorescence spectra were measured at room temperature and important spectroscopic parameters were calculated. Through the comparison of spectroscopic parameters of Yb:YAP and Yb: YAG, all results indicate that 15at% Yb:YAP crystal is a potential candidate used for compact, efficient thin chip lasers when the laser output wavelength is 1012 or 1038nm. [Copyright &y& Elsevier]