Henan University of Technology

About: Henan University of Technology is a education organization based out in Zhengzhou, China. It is known for research contribution in the topics: Catalysis & Starch. The organization has 7648 authors who have published 6503 publications receiving 73067 citations. The organization is also known as: Hénán Gōngyè Dàxué.

Cooperative photoredox and chiral hydrogen-bonding catalysis

Abstract: Chiral hydrogen-bonding catalysis is a classic strategy in asymmetric organocatalysis, and it has been extensively used in a variety of fundamental chemical transformations. At the same time, visible light-driven photoredox catalysis is a powerful and sustainable tool commonly used in radical chemistry. The intriguing combination of these two catalysis platforms would open a new avenue for the direct and highly efficient synthesis of enantioenriched compounds. Inspired by the conceptual breakthrough of T. Bach, in recent years, significant progress has been made in cooperative photoredox and chiral hydrogen-bonding catalysis. By developing a variety of important types of reactions, a wide range of valuable chiral compounds have been successfully synthesized. In this review, the advances in this key area are systematically described, and the examples are organized according to the distinct bond-forming patterns in the construction of the stereocentres.

A comparative study of mechanical and microstructural characteristics of aluminium and titanium undergoing ultrasonic assisted compression testing

Abstract: The mechanism of ultrasonic softening effect has been widely investigated and used in the metal material processing area. Deficiency discussion, however, has been focused on the residual effect of ultrasonic vibration on the plasticity of metals only. In this study, ultrasonic vibration assisted compression (UAC) experiments were carried out using commercially pure aluminium and titanium samples. Despite the similar ultrasonic softening effect, different ultrasonic residual effects were observed in the aluminium and titanium samples. Aluminium exhibited a residual hardening phenomenon, whereas in titanium the initial residual hardening effect transferred to a residual softening effect with an increase in amplitude of the applied ultrasonic vibration. Electron backscatter diffraction (EBSD) characterizations revealed that substructure multiplication, texture evolution and dynamic recrystallization caused by the ultrasonic vibration are the main causes of the residual hardening effect of aluminium. The boundary strengthen mechanism based Hall–Petch relationship was used to explain the mechanism and to predict the influence of the ultrasonic residual effect for aluminium. For the titanium, it was found that the ultrasonic vibration reduced the density of deformation twinning in the specimen, and the evolution of residual effect was analysed from the aspects of grain refinement, deformation twinning induced strain hardening. By quantitative study, the main reason for the residual hardening effect of UAC aluminium sample is identified to be the ultrasonic vibration induced grain refinement, while for the titanium, the weakened strain hardening effect induced by deformation twinning should be the main factor accounting for the residual softening of titanium. Also the ultrasonic vibration could have a similar influence as that of the thermal treatment to the titanium sample, resulting in the yield point elongation (YPE) phenomenon.

In Situ Formation of Hierarchical Bismuth Nanodots/Graphene Nanoarchitectures for Ultrahigh-Rate and Durable Potassium-Ion Storage.

Abstract: Metallic bismuth (Bi) has been widely explored as remarkable anode material in alkali-ion batteries due to its high gravimetric/volumetric capacity. However, the huge volume expansion up to ≈406% from Bi to full potassiation phase K3 Bi, inducing the slow kinetics and poor cycling stability, hinders its implementation in potassium-ion batteries (PIBs). Here, facile strategy is developed to synthesize hierarchical bismuth nanodots/graphene (BiND/G) composites with ultrahigh-rate and durable potassium ion storage derived from an in situ spontaneous reduction of sodium bismuthate/graphene composites. The in situ formed ultrafine BiND (≈3 nm) confined in graphene layers can not only effectively accommodate the volume change during the alloying/dealloying process but can also provide high-speed channels for ionic transport to the highly active BiND. The BiND/G electrode provides a superior rate capability of 200 mA h g-1 at 10 A g-1 and an impressive reversible capacity of 213 mA h g-1 at 5 A g-1 after 500 cycles with almost no capacity decay. An operando synchrotron radiation-based X-ray diffraction reveals distinctively sharp multiphase transitions, suggesting its underlying operation mechanisms and superiority in potassium ion storage application.

Preparation of astaxanthin-loaded liposomes: characterization, storage stability and antioxidant activity

Abstract: Astaxanthin-loaded liposomes were prepared by employing a thin-film ultrasound method with the utilization of soy phosphatidylcholine. The preparation conditions of astaxanthin-loaded liposomes wer...