A lightning current measurement method using a Rogowski coil based on an integral circuit with low-frequency attenuation feedback was proposed to address the issue of low-frequency distortion in the measurement of lightning currents on transmission lines using Rogowski coils. Firstly, the causes of low-frequency distortion in lightning current measurements using Rogowski coils were analyzed from the perspective of frequency domains. On this basis, an integration correction optimization circuit with a low-frequency attenuation feedback network was designed to correct the low-frequency distortion.
View Article and Find Full Text PDFFormal 1,3-migration of hydroxy and acyloxy groups initiated by α-imino rhodium carbene was achieved, and the following selective annulations of the corresponding zwitterions could efficiently afford azepane derivatives. Benefiting from a time-saving procedure as well as a good functional group tolerance, this unique migration-annulation protocol could provide an efficient tool for synthesizing seven-membered -heterocycles. The plausible mechanism is discussed.
View Article and Find Full Text PDFTetrahydrocarbazoles and pyrrolo[3,4-]carbazoles could be synthesized conveniently through sequential reactions of ester-tethered 1-sulfonyl-1,2,3-triazoles and indoles. The reaction conditions were mild and the procedures were quite simple. Moreover, the key intermediate α,β-unsaturated imine acted as a [2C] synthon in the [4 + 2] cycloaddition reaction, and the imino group could be used as a nucleophile to construct the fourth ring.
View Article and Find Full Text PDFBackground: CTX-M-55 extended-spectrum beta-lactamases are being rapidly disseminated and transmitted in clinical practices around the world. The genetic contexts of the transferable plasmid-mediated bla gene in Enterobacteriaceae were detected and characterized in this study.
Methods: Isolates were obtained from the First Affiliated Hospital of Zhengzhou University between September 2015 and March 2016.