Neutron diffraction has been used to study the lattice and magnetic structures of the insulating and superconducting RbyFe1.6+xSe2. For the insulating RbyFe1.6+xSe2, neutron polarization analysis and single crystal neutron diffraction unambiguously confirm the earlier proposed √ 5 × √ 5 block antiferromagnetic structure. For superconducting samples (Tc = 30 K), we find that in addition to the tetragonal √ 5 × √ 5 superlattice structure transition at 513 K, the material develops a separate √ 2 × √ 2 superlattice structure at a lower temperature of 480 K. These results suggest that superconducting RbyFe1.6+xSe2 is phase separated with coexisting √ 2 × √ 2 and √ 5 × √ 5 superlattice structures.
The Dragon lake diversion channel (DLDC) is the only river that recharges Dragon Lake, an artificial lake in China. This paper examines the main factors influencing water quality by investigating point source and non-point source pollutants along the main route. Based on the complicated system of rivers and desilting basins, a three-dimensional water quality model using environmental fluid dynamics code (EFDC) was developed. The model of DLDC was calibrated and verified using observed data. The error ranges of river water level, total phosphorus, total nitrogen and chemical oxygen demand were within 5%, 10%, 16% and 20%, respectively, all of which meet the precision requirement. The model was employed to predict the concentrations of pollutants in the main stream under current pollution loads within a year and a flood lasting for 24 hours. The results revealed that the main pollution sources that influence the water quality of waterways were the point sources followed by the non-point pollution sources. Water quality improved when large water quantities were delivered and this trend can be described as dilution. The water quality of the Dongfeng main channel meets the requirement; however, the water quality of the Dongfeng River is somewhat poor, and the water quality of the Wei River is seriously contaminated. To address these problems, we suggest that the Dongfeng River and Wei River adopt a culvert under its riverbeds.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.