Enhancement of liquideliquid micromixing performance in curved capillary microreactor by generation of Dean vortices

Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes was designed to generate Dean flow,which was used to enhance the liquideliquid micromixing performance.The VillermauxeDushman probe reaction was employed to characterize the micromixing performance in different curved capillary microreactors.The effects of experiment parameters such as liquid flow rate,inner diameter,tube length,and curve diameter on micromixing performance were systematically investigated.Under the optimal conditions,the minimum value of the segmentation factor XS was 0.008.It was worth noting that at the low Reynolds number(Re<30),the change of curved shape on the capillary microreactor can significantly improve the micromixing performance with XS reduced by 37.5%.Further,the correlations of segment index XS with dimensionless factor such as Reynolds number or Dean number were developed,which can be used to predict the liquide liquid micromixing performance in capillary microreactors.

The visible light-triggered nonvolatile memory performances in melamine-decorated <110>-oriented lead halide perovskites: A photo-responsive structural evolution insight

The exploration of novel photo/thermal-responsive nonvolatile memorizers will be beneficial for energysaving memories.Herein,new<110>-oriented perovskites using single template melamine,i.e.,[(MLAI-H_(2))(PbX_(4))]_n(X=Br (α-1),Cl (α-2),MLAI=melamine) have been prepared and their structures upon irradiation of visible light have been investigated.They have been fabricated as nonvolatile memory devices with structures of ITO/[(MLAI-H_(2))(PbX_(4))]_n/PMMA/Ag (device-1:X=Br,device-2:X=Cl),which can exhibit unique visible light-triggered binary nonvolatile memory performances.Interestingly,the silent or working status can be monitored by visible chromisms.Furthermore,the light-triggered binary resistive switching mechanisms of these ITO/[(MLAI-H_(2))(PbX_(4))]_n/PMMA/Ag memory devices have been clarified in terms of EPR,fluorescence,and single-crystal structural analysis.The presence of light-activated traps in<110>-oriented[(MLAI-H_(2))(PbX_(4))]_n perovskites are dominated in the appearance of light-triggered resistive switching behaviors,based on which the inverted internal electrical fields can be established.According to the structural analysis,the more distorted PbX_6octahedra,higher corrugated<110>-oriented perovskite sheets,and more condensed organic-inorganic packing in Br-containing perovskite are beneficial for the stabilization of light-activated traps,which lead to the better resistive switching behavior of device-1.This work can pave a new avenue for the establishment of novel energy-saving nonvolatile memorizers used in aerospace or military industries.

Conversion of acetate and glyoxylate to fumarate by a cell-free synthetic enzymatic biosystem

Fumarate is a value-added chemical that is widely used in food,medicine,material,and agriculture industries.With the rising attention to the demand for fumarate and sustainable development,many novel alternative ways that can replace the traditional petrochemical routes emerged.The in vitro cell-free multi-enzyme catalysis is an effective method to produce high value chemicals.In this study,a multi-enzyme catalytic pathway comprising three enzymes for fumarate production from low-cost substrates acetate and glyoxylate was designed.The acetyl-CoA synthase,malate synthase,and fumarase from Escherichia coli were selected and the coenzyme A achieved recyclable.The enzymatic properties and optimization of reaction system were investigated,reaching a fumarate yield of 0.34 mM with a conversion rate of 34%after 20 h of reaction.We proposed and realized the conversion of acetate and glyoxylate to fumarate in vitro using a cell-free multi-enzyme catalytic system,thus providing an alternative approach for the production of fumarate.

Haloplumbate Nanochains Templated by Quaternary Phosphorus:Good Water Stabilities,Thermochromic Luminescence and Photocurrent Responses

Two triphenylmethylphosphonium/haloplumbate hybrids,i.e.,[(PPh3Me)2(Pb2I6)∙CH3CN]n(1)and[(PPh3Me)(PbBr3)]n(2),have been prepared,in which the(PbX3)nn-nanochains built from face-sharing PbX6 octahedra are surrounded by organic templates to assemble the core-shell quantum well.Besides,C−H…πinteractions among Ph3PMe+cations can also be detected,which give rise to the 2-D organic layer of 1 and 1-D chain for 2.The good water stabilities could be induced by the strong C−H…πinteractions,which can deter the hydrolysis reaction.The energy band gaps of this work mainly derive from the charge transfer of organic components,but their luminescence stems from the inorganic(PbX3)nn-nanochains with co-existence of free excitons and self-trapped excitons.At temperature lower than 117 K,strong quantum confinement will rule out the free excitons,and self-trapped excitons will dominate,resulting in red-shift luminescence.Moreover,effective and repeatable photocurrent responses can be found in these hybrids.