Mixed-Dimensional (2D/3D/3D) Heterostructured Vanadium Oxide with Rich Oxygen Vacancies for Aqueous Zinc Ion Batteries with High Capacity and Long Cycling Life.

Heterostructure engineering and oxygen vacancy engineering are the most promising modification strategies to reinforce the Zn2+ ion storage of vanadium oxides. Herein, a rare mixed-dimensional material (VOx), composed of V2O5 (2D), V3O7 (3D), and V6O13 (3D) heterostructures, rich in oxygen vacancies, was synthesized via thermal decomposition of layered ammonium vanadate. The VOx cathode provides an exceptional discharge capacity (411 mA h g-1 at 0.1 A g-1) and superior cycling stability (the capacity retention remains close to 100% after 800 cycles at 2 A g-1) for aqueous zinc-ion batteries (AZIBs). Ex situ characterizations confirm that the byproduct Zn3V2O7(OH)2·nH2O is generated/decomposed during discharge/charge processes. Furthermore, VOx demonstrates reversible intercalation/deintercalation of H+/Zn2+ ions, enabling efficient energy storage. Remarkably, a reversible crystal-to-amorphous transformation in the V2O5 phase of VOx during charge-discharge was observed. This investigation reveals that mixed-dimensional heterostructured vanadium oxide, with abundant oxygen vacancies, serves as a highly promising electrode material for AZIBs, further advancing the comprehension of the storage mechanism within vanadium-based cathode materials.

Enantioselective Synthesis of 3-Alkynyl-3-hydroxyindolin-2-ones by Copper-Catalyzed Asymmetric Addition of Terminal Alkynes to Isatins.

A 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.

Copper-catalyzed annulation of heteroaromatic ß-halo-α,ß-unsaturated carboxylic acids with alkynes for the synthesis of indolo[2,3-c]pyrane-1-ones and thieno[2,3-c]pyrane-7-ones.

The annulation of heteroaromatic ß-halo-α,ß-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 ß-halo-α,ß-unsaturated carboxylic acids.

Finite element simulation for a new disc-type ultrasonic stator.

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. In this model, a 3-dimensional (D) mechanical element with an extra electrical degree of freedom is used to simulate dynamic vibration modes and analyze characteristic responses such as electrical impedance response, phase response, and mechanical frequency response for a new disc-type piezoelectric ultrasonic stator. An adaptive boundary condition, simple support condition with three nonequal-triangular fixed points near the edge for the mechanism design of a new disc-type piezoelectric ultrasonic stator is defined so that a lateral elliptical motion of the contact point between stator and rotor can be realized for driving the rotor. The finite element results have been compared with the experimental measurements. As a result, the analysis model seems to be similar to the real condition.