Fatigue limit assessment of a 6061 aluminum alloy based on infrared thermography and steady ratcheting effect

To quickly predict the fatigue limit of 6061 aluminum alloy,two assessment methods based on the temperature evolution and the steady ratcheting strain difference under cyclic loading,respectively,were proposed.The temperature evolutions during static and cyclic loadings were both measured by infrared thermography.Fatigue tests show that the temperature evolution was closely related to the cyclic loading,and the cyclic loading range can be divided into three sections according to the regular of temperature evolution in different section.The mechanism of temperature evolution under different cyclic loadings was also analyzed due to the thermoelastic,viscous,and thermoplastic effects.Additionally,ratcheting strain under cyclic loading was also measured,and the results show that the evolution of the ratcheting strain under cyclic loading above the fatigue limit undergone three stages:the first increasing stage,the second steady state,and the final abrupt increase stage.The fatigue limit of the 6061 aluminum alloy was quickly estimated based on transition point of linear fitting of temperature increase and the steady value of ratcheting strain difference.Besides,it is feasible and quick of the two methods by the proof of the traditional S-N curve.

Graphene oxide as a hole extraction layer loaded on BiVO_(4)photoanode for highly efficient photoelectrochemical water splitting

The tailor-made oxygen evolution catalysts(OECs)paired with photoanodes offer a path to promote water oxidation kinetics;however,the unsatisfied interface between OECs and photoanode sets a barrier for efficient charge transfer.Herein,a graphene oxide(GO)layer to promote the charge transfer from BiVO_(4)(BVO)to NiOOH OEC is reported.It is found that GO layer inserted between BVO and NiOOH can not only serve as hole extraction layer due to its hole storage capability,but also improve the stability.Finally,the rationally designed NiOOH/GO/BVO photoanode achieves a photocurrent density of 3.81 mA·cm^(-2)at 1.23 V(vs.reversible hydrogen electrode(RHE)),which is 3.85 times as high as that of bare BVO.This work opens up low-cost auxiliary materials for enhancing photoelectrochemical water splitting.

Chiral Thermally Activated Delayed Fluorescence-Active Macrocycles Displaying Efficient Circularly Polarized Electroluminescence

An efficient strategy for constructing chiral macrocycles with both thermally activated delayed fluorescence(TADF)and highly efficient circularly polarized electroluminescence(CPEL)properties was developed.Consequently,a pair of macrocyclic enantiomers(+)-(R,R)-MC and(−)-(S,S)-MC was synthesized by a combination of chiral octahydro-binaphthol moiety with triazine-based TADF skeleton.The chiral macrocycles exhibited obvious TADF properties with a lowΔE_(ST) of 0.067 eV,aggregation-induced emission behaviors,and high photoluminescence quantum yields of up to 79.7%.Moreover,the macrocyclic enantiomers showed mirror images in circular dichroism spectra and circularly polarized luminescence signals.Especially,the chiralmacrocycleswere suitable for the preparation of solution-processed circularly polarized organic light-emitting diodes,which displayed excellent device performances with a highmaximum external quantum efficiency of up to 17.1%,low-efficiency roll-off of 3.5%at 1000 cdm^(−2),andintenseCPELalong with electroluminescence dissymmetry factor of 1.7×10^(−3).