Understanding the Reversible Reactions of Li-N_(2) Battery Catalyzed With SnO_(2)

Metal–N_(2) battery can be applied in both energy storage and electrochemical nitrogen reduction reaction(NRR);however,there has been only extraordinarily little study on metal–N_(2) battery since its electrochemical reversibility still needs further proofs.And its electrochemical performances also need to be enhanced.Herein,we investigated the discharge–charge reactions between Li anode and N_(2) cathode via designing an efficient catalyst of nanosized SnO_(2) particles dispersed on N-doped carbon nanosheets(SnO 2@NC)for the Li-N_(2) battery,with good cyclic stability and a high specific capacity of 0.25 mA h(~500 mA h g^(−1))at a large current density of 1000 mA g^(−1).The electrochemical reversibility of both NRR in the discharge process and nitrogen extraction reaction in the charge process for Li-N 2 battery is discussed.Time-of-flight secondary ion mass spectrometry results imply that the SnO_(2)@NC can effectively promote the adsorption of N_(2) and the activation of NRR in the discharge process.Furthermore,ex situ X-ray photoelectron spectroscopy and Fourier transform infrared tests are performed to study the electrochemical reversibility of Li-N_(2) battery.It can be proved that the formation and decomposition of discharging product Li_(3)N are electrochemical reversible during cycling in our deigned Li-N_(2) battery system with SnO_(2)@NC catalyst.

Structural Stress-Fatigue Life Curve Improvement of Spot Welding Based on Quasi‑Newton Method

ΔF-N curves are usually used to predict the fatigue life of spot welding in engineering,but they are time-consuming and laborious and not universal.For the purpose of predicting the fatigue life of spot welding accurately and efficiently,tensile-shear fatigue tests were conducted to obtain the fatigue life of spot-welded specimens with different sheet thicknesses combinations.These specimens were simulated by using the finite element method,and the structural stress was theoretically calculated.In the double logarithmic coordinate system,the structural stress-fatigue life(S-N)curve of spot welding was fitted by the least-squares method,based on the quasi-Newton method.The square of the correlation coefficient of the S-N curve was taken as the optimization objective,with the correction coefficients of force,bending moment,spot welding diameter,and sheet thickness as the variables.During the optimization process,three different ways were utilized to get three optimized spot welding S-N curves,which are suitable for different situations.The results show that the fitting effect of the S-N curve is improved,the data points are more compact,and the optimization effect is significant.These S-N curves can be used to predict the fatigue life,which provide the basis for practical engineering application.

Preparation of SiO_2/TiO_2 Janus particles by electrostatic assembly,hydrolysis and calcination

This paper describes a novel chemical method for preparing SiO2/TiO2 Janus particles. First, polystyrene （PSt）/SiO2 particles with a raspberry-like structure are prepared by electrostatic assembly. The influences of the reaction time of sulfonation and the treatment times of polyelectrolyte solutions （PDADMAC, PSS） on PSt and SiO2 are investigated with respect to the surface charge density of the particles. SiO2/TiO2 Janus particles are then obtained by hydrolysis of butyl titanate on the surface of PSt/SiO2 particles followed by a calcination process. Particle size analyzer, Zeta potential instrument, FTIR, TEM and SEM are used to characterize the particle size, the amount of charge on the surface of PSt and SiO2 particles and the compositions and morphologies of PSt/SiO2, SiO2/Ti02 and PSt/SiO2/Ti02. The diameters of the PSt, SiO2, PSt/Si02 and SiO2/Ti02 particles are 2.0 t^m, 303 nm, 2.7 bcm and 330 nm, respectively.

Synthesis of PS/Ag asymmetric hybrid particles via phase separation and self-assembly

This article presents a facile approach to preparation of polystyrene/silver （PS/Ag） asymmetric hybrid par- ticles. In this method, polystyrene/polyglycidyl methacrylate （PS/PGMA） Janus particles were synthesized via internal phase separation triggered by evaporation of dichloromethane （DCM） from PS/PGMA/DCM- in water emulsion droplets. Then, the Janus particles were aminated and sequentially carboxylated to obtain PS/PGMA-NH2 and PS/PGMA-COOH particles. Ag＋ self-assembled on the surface of PGMA hemi- sphere of the functionalized PS/PGMA particles by coordinating with amine/carboxyl. PS/Ag asymmetric hybrid particles with 7.29 wt% of Ag were obtained by reduction of Ag＋, Scanning electron microscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy results confirmed that Ag was asymmetrically distributed on the surface of polymer particles.

PBX/Knotted 1 homeobox-2(PKNOX2)is a novel regulator of myocardial fibrosis

Much effort has been made to uncover the cellular heterogeneities of human hearts by single-nucleus RNA sequencing.However,the cardiac transcriptional regulation networks have not been systematically described because of the limitations in detecting transcription factors.In this study,we optimized a pipeline for isolating nuclei and conducting single-nucleus RNA sequencing targeted to detect a higher number of cell signal genes and an optimal number of transcription factors.With this unbiased protocol,we characterized the cellular composition of healthy human hearts and investigated the transcriptional regulation networks involved in determining the cellular identities and functions of the main cardiac cell subtypes.Particularly in fibroblasts,a novel regulator,PKNOX2,was identified as being associated with physiological fibroblast activation in healthy hearts.To validate the roles of these transcription factors in maintaining homeostasis,we used single-nucleus RNA-sequencing analysis of transplanted failing hearts focusing on fibroblast remodelling.The trajectory analysis suggested that PKNOX2 was abnormally decreased from fibroblast activation to pathological myofibroblast formation.Both gain-and loss-of-function in vitro experiments demonstrated the inhibitory role of PKNOX2 in pathological fibrosis remodelling.Moreover,fibroblast-specific overexpression and knockout of PKNOX2 in a heart failure mouse model induced by transverse aortic constriction surgery significantly improved and aggravated myocardial fibrosis,respectively.In summary,this study established a high-quality pipeline for single-nucleus RNA-sequencing analysis of heart muscle.With this optimized protocol,we described the transcriptional regulation networks of the main cardiac cell subtypes and identified PKNOX2 as a novel regulator in suppressing fibrosis and a potential therapeutic target for future translational studies.