Matter and radiation at extremes:Prospects and impacts

High-energy-density science(HEDS)has been recognized as a comprehensive new area of physical science,with the potential to revolutionize various scientific and technological fields,including nuclear fusion,particle acceleration,astrophysics,and the properties of condensed matter under extreme conditions.That is why this journal,Matter and Radiation at Extremes(MRE),was established five years ago by the China Academy of Engineering Physics(CAEP)with the mission of informing the worldwide scientific community about progress related to HEDS,whether this be in the basic physics.

Integrative genomics reveals paths to sex dimorphism in Salix purpurea L

Sex dimorphism and gene expression were studied in developing catkins in 159 F 2 individuals from the bioenergy crop Salix purpurea,and potential mechanisms and pathways for regulating sex development were explored.Differential expression,eQTL,bisulfite sequencing,and network analysis were used to characterize sex dimorphism,detect candidate master regulator genes,and identify pathways through which the sex determination region(SDR)may mediate sex dimorphism.Eleven genes are presented as candidates for master regulators of sex,supported by gene expression and network analyses.These include genes putatively involved in hormone signaling,epigenetic modification,and regulation of transcription.eQTL analysis revealed a suite of transcription factors and genes involved in secondary metabolism and floral development that were predicted to be under direct control of the sex determination region.Furthermore,data from bisulfite sequencing and small RNA sequencing revealed strong differences in expression between males and females that would implicate both of these processes in sex dimorphism pathways.These data indicate that the mechanism of sex determination in Salix purpurea is likely different from that observed in the related genus Populus.This further demonstrates the dynamic nature of SDRs in plants,which involves a multitude of mechanisms of sex determination and a high rate of turnover.

Emergence of local scaling relations in adsorption energies on high-entropy alloys

Alloying has been proposed to circumvent scaling relations between the adsorption energies thus allowing for the complete optimization of multistep reactions.Herein the fidelity of scaling rules on high-entropy alloy(HEA)surfaces is assessed focusing on hydrogen-containing molecules,^(*)AH_(x) for A=C and N(x=0,1,2,3),A=S(x=0,1,2)and A=O(x=0,1).Using an adsorbate-and site-specific deep learning model to rapidly compute the adsorption energies on CoMoFeNiCu HEA surfaces,the energies of ^(*)AH_(x) and ^(*)A are shown to be linearly correlated if ^(*)A and ^(*)AH_(x) have identical adsorption site symmetry.However,a local linear dependence emerges between the configuration-averaged adsorption energies irrespective of the site symmetry.Although these correlations represent a weaker form of the scaling relationships,they are sufficient to prohibit the optimization of multistep reactions.The underpinning of this behavior is twofold(1)the nearsightedness principle and(2)the narrow distribution of the adsorption energies around the mean-field value.While the nearsightedness is general for all electronic systems,the second criterion applies in HEAs with relatively strong reactive elements.The present findings strongly suggest that alloys may not generally enable the breaking of scaling relationships.

A Quadrature-Based Kinetic Model for Dilute Non-Isothermal Granular Flows

A moment method with closures based on Gaussian quadrature formulas is proposed to solve the Boltzmann kinetic equation with a hard-sphere collision kernel for mono-dispersed particles.Different orders of accuracy in terms of the moments of the velocity distribution function are considered,accounting for moments up to seventh order.Quadrature-based closures for four different models for inelastic collisionthe Bhatnagar-Gross-Krook,ES-BGK,the Maxwell model for hard-sphere collisions,and the full Boltzmann hard-sphere collision integral-are derived and compared.The approach is validated studying a dilute non-isothermal granular flow of inelastic particles between two stationary Maxwellian walls.Results obtained from the kinetic models are compared with the predictions of molecular dynamics(MD)simulations of a nearly equivalent system with finite-size particles.The influence of the number of quadrature nodes used to approximate the velocity distribution function on the accuracy of the predictions is assessed.Results for constitutive quantities such as the stress tensor and the heat flux are provided,and show the capability of the quadrature-based approach to predict them in agreement with the MD simulations under dilute conditions.