In general, the P-centered ring-opening of quaternary phosphirenium salts (QPrS) predominantly leads to hydrophosphorylated products, while the C-centered ring-opening is primarily confined to intramolecular nucleophilic reactions, resulting in the formation of phosphorus-containing cyclization products instead of difunctionalized products generated through intermolecular nucleophilic processes. Here, through the promotion of ring-opening of three-member rings by iodine anions and the quenching of electronegative carbon atoms by iodine cations, we successfully synthesize β-functionalized vinylphosphine oxides by the P-addition of QPrS intermediates generated in situ. Multiple β-iodo-substituted vinylphosphine oxides can be obtained with exceptional regio- and stereo-selectivity by reacting secondary phosphine oxides with unactivated alkynes.
View Article and Find Full Text PDFThe rotation motion is one of the most basic dynamic units, whose accurate measure-ment is essential to the aspects of inertial navigation, mechanical manufacturing, robot control. Currently, the laser interferometry (LI), the sensor-based and autocollimator-based methods are commonly applied to the rotation motion measurement. However, they are always difficult to meet the requirements of high-accuracy measurement and wide frequency range.
View Article and Find Full Text PDFBiomimetics (Basel)
November 2022
Live fish in nature exhibit various stiffness characteristics. The anguilliform swimmer, like eels, has a relatively flexible body, while the thunniform swimmer, like the swordfishes, has a much stiffer body. Correspondingly, in the design of biomimetic robotic fish, how to balance the non-uniform stiffness to achieve better propulsion performance is an essential question needed to be answered.
View Article and Find Full Text PDFBiomimetics (Basel)
August 2022
In nature, live fish has various deformable fins which are capable to promote the swimming speed, efficiency, stability, and thrust generation. However, this feature is rarely possessed by current man-made biomimetic robotic fishes. In this paper, a novel deformable caudal fin platform is proposed to improve thrust generation of biomimetic robotic fish.
View Article and Find Full Text PDFAn efficient and novel visible-light-promoted radical difluoromethylation of enol acetates for the synthesis of α-CFH-substituted ketones has been described. Upon irradiation under blue LED with catalytic amounts of -Ir(ppy), this photocatalytic procedure employs difluoromethyltriphenylphosphonium bromide as a radical precursor. Various α-CFH-substituted ketones are successfully created via designed systems based on the SET process.
View Article and Find Full Text PDFLi doping is a well-known, simple, yet efficient strategy to optimize the properties of upconverting materials. Nonetheless, the position of Li in the lattice and the mechanism of upconversion enhancement are still controversial, especially in Yb/Er co-doped YO. This paper presents a comprehensive investigation of the above issues (i.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
June 2017
This study investigated the chromium (Cr) occurrence and distribution along the Loushan River adjacent to a chromium slag heap. The speciation and chemical fractionation of Cr in different environmental media were determined. The potential ecological risks for the surrounding environment were assessed on the basis of both potential ecological risk index (RI) and risk assessment code (RAC).
View Article and Find Full Text PDFHuan Jing Ke Xue
October 2016