A series of conjugated copolymers with an identical backbone (PBDT-DPP) but different fluorination numbers and positions were synthesized, and the impact of fluorine atoms on the structure–property-device performance was comprehensively investigated.

Our integrated evidence indicates morphological and genetic polymorphisms in Allium cyathophorum and thus the need for a taxonomic revision. First, A. cyathophorum var. farreri is reinstated as A. farreri. Second, a cryptic allotetraploid population geographically confined to the intermediate zone between A. cyathophorum and A. farreri is described here as a new species named A. tetraploideum. Morphological characters that differentiate these three species from each other, as well as information on their distribution range and habitat, are provided.

In this paper, the contents of these elements including Cu, Fe, Mn, Zn, Al, Cd, Pb, Ti and As were determined by ICP-AES technique, which elements originated from maca from different places. Detection limits ranged 0.0022 ug/ml-1 and 0.077ug/ml-1, the relative standard deviations for all these elements were lower than 2%, and recovery rates ranged 95.56% and 106.2%. The results showed that there were rich metal elements in maca from different places; contents of Fe and Al were highest; contents of Mn, Zn, Cu and Ti were moderately high, and contents of As, Cd and Pb were lowest. Futhermore, Cu, Fe, Mn, Zn were essential to people’s health, and Al, Cd, As, Pb and Ti had potentially physiologically toxic. Finally, concentrations of elements within macafrom different places were different, which may have some relations with the environment where maca grew. As a result, the determining method which elements of maca. are determined by ICP-AES is rapid, accurate and convenient, and wild macamay contain toxic elements because of pollutional soil and environment, so macacultivated artificially can effectively reduce harmful elements.

The experiment improved the synthetic methods of preparing expanded graphite, using the mixture of H2SO4 and HNO3 as the acid, KMnO4 as oxidizing agent and adopting chemical oxidization method to prepare the expanded graphite under the conditions of different temperature. We can get the optimum conditions of preparing expanded graphite by orthogonal experiment.