Heterostructure engineering and oxygen vacancy engineering are the most promising modification strategies to reinforce the Zn ion storage of vanadium oxides. Herein, a rare mixed-dimensional material (), composed of VO (2D), VO (3D), and VO (3D) heterostructures, rich in oxygen vacancies, was synthesized via thermal decomposition of layered ammonium vanadate. The cathode provides an exceptional discharge capacity (411 mA h g at 0.
View Article and Find Full Text PDFA highly efficient copper-catalyzed asymmetric addition of terminal alkynes to isatins has been developed. In the presence of a catalytic amount of copper iodide and a chiral phosphine ligand, the reaction gave the corresponding chiral 3-alkynyl-3-hydroxyindolin-2-ones in high yields with high enantioselectivity. This methodology has a broad substrate scope, and the synthetic utility of the present protocol was further demonstrated by the transformation of chiral alkynylation products.
View Article and Find Full Text PDFThe annulation of heteroaromatic β-halo-α,β-unsaturated carboxylic acids with alkynes proceeds efficiently in the presence of Cu(OAc)2·H2O as a catalyst to afford the corresponding indolo[2,3-c]pyrane-1-ones and thieno[2,3-c]pyrane-7-ones in moderate to good yields. This strategy offers a simple and efficient route for the synthesis of indolo[2,3-c]pyrane-1-ones and thieno[2,3-c]pyrane-7-ones with good tolerance to a variety of functional groups from easily available heteroaromatic β-halo-α,β-unsaturated carboxylic acids.
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
April 2003
This paper is concerned with the development of a new disc-type piezoelectric ultrasonic stator. Linear piezoelectric, mechanical, and piezoelectro-mechanic behaviors of a metal disc structure embedded with piezoelectric actuator are considered. Using a finite element method, a dynamic formulary is modeled for the new disc-type piezoelectric ultrasonic stator.
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