Study of neutron density fluctuation and neutron-proton correlation in Au+Au collisions using PYTHIA8/Angantyr

Utilizing the PYTHIA8 Angantyr model,which incorporates the multiple-parton interaction(MPI)based color reconnection(CR)mechanism,we study the relative neutron density fluctuation and neutron-proton correlation in Au+Au collisions at√sNN=7.7,11.5,14.5,19.6,27,39,62.4,and 200 GeV.In this study,we not only delve into the dependence of these two remarkable observations on rapidity,centrality,and energy,but also analyze their interplay with the MPI and CR.Our results show that the light nuclei yield ratio of protons,deuterons,and tritons,expressed by the elegant expression N_(t)N_(p)/N^(d)^(2),remains unchanged even as the rapidity coverage and collision centrality increase.Interestingly,we also reveal that the effect of CR is entirely dependent on the presence of the MPI;CR has no impact on the yield ratio if the MPI is off.Our findings further demonstrate that the light nuclei yield ratio experiences a slight increase with increasing collision energy,as predicted by the PYTHIA8 Angantyr model;however,it cannot describe the non-monotonic trend observed by the STAR experiment.Based on the Angantyr model simulation results,it is essential not to overlook the correlation between neutron and proton fluctuations.The Angantyr model is a good baseline for studying collisions in the absence of a quark-gluon plasma system,given its lack of flow and jet quenching.

A solvent-free process enabling ZnO/porous carbon with enhanced microwave absorption

Exploring a simple,rapid,solvent-free synthetic method for mass production of cheap,broadband mi-crowave absorbers remains the main challenge.Here,a mild solvent-free procedure is reported to syn-thesize zinc oxide nanoparticles(ZnO NPs)embedded in porous carbon derived from mixing sucrose and zinc nitrate hexahydrate.The characteristic morphology and the ZnO NPs distribution in these compos-ites were tuned using the different raw materials proportions.The mesoporous structure of porous car-bon benefits the compositional advantages between carbon foam and ZnO NPs.The optimal synthesized ZnO/C-2 carbon material demonstrates the strongest absorption of-41.7 dB with a frequency of 14.5 GHz at a thin thickness of 2 mm,and its widest effective absorption is close to 6 GHz(12.2-17.8 GHz).This work produces a feasible route for the sensible design of other effective microwave absorbers for large-scale production.

Interlayer sensitized van der Waals heterojunction photodetector with enhanced performance

Although photodetection based on two-dimensional(2D)van der Waals(vdWs)P-N heterojunction has attracted extensive attention recently,their low responsivity(R)due to the lack of carrier gain mechanism in reverse bias or zero bias operation hinders their applications in advanced photodetection area.Here,a black phosphorus/rhodamine 6G/molybdenum disulfide(BP/R6G/MoS_(2))photodiode with high responsivity at reverse bias or zero bias has been achieved by using interfacial charge transfer of R6G molecules assembled between heterojunction layers.The formed vdWs interface achieves high performance photoresponse by efficiently separating the additional photogenerated electrons and holes generated by R6G molecules.The devices sensitized by the dye molecule R6G exhibit enhanced photodetection performance without sacrificing the photoresponse speed.Among them,the R increased by 14.8-20.4 times,and the specific detectivity(D^(*))increased by 24.9-34.4 times.The strategy based on interlayer assembly of dye molecules proposed here may pave a new way for realizing high-performance photodetection based on 2D vdWs heterojunctions with high responsivity and fast response speed.

Inter-harmonics in multi-terminal VSC-based HVDC systems

Multi-terminal voltage sourced converter(VSC)-based high voltage direct current (HVDC) system composes of a number of VSCs connected to an HVDC grid (or dc grid).The dc grid is often configured by cable interconnections between converter stations,thus imposing resonance issues affecting harmonic interaction in the system.Based on the harmonic transfer characteristics of VSC and HVDC systems,the appearance and the interaction of inter-harmonics in the multi-terminal VSC-based HVDC system are analyzed.Simulation models are built and implemented using SimPowerSystems in MATLAB.The simulation results show that,a series of inter-harmonics are produced and tend to be dominant in low-frequency range.Especially in the dc grid,the inter-harmonic transfer can be magnified due to inter-harmonic resonances.The complex resonance issues in the dc grid are investigated in combination with interaction through the VSC,it is beneficial to harmonic filter designs as well as other harmonic mitigation methods.