Can HHe^(+)exist at high pressure:Exploration of high pressure induced HF–He compounds

HHe^(+)is considered as the strongest acid and most powerful proton donor known to human.Whether HHe^(+)exists at planetary high pressure environment is a quite important problem in physics,chemistry and planetary sciences.Here,using the ab initio evolutionary algorithm USPEX package,we searched HF–He system,which was reported as the most possible candidate to contain HHe^(+).The calculation proved HHe^(+)cannot form at pressure<1000 GPa,due to a conflict between the covalent component in symmetric hydrogen bond and ionic HHe^(+).Although He atoms have no chemical bonding with other elements,they can supply a chemical pressure,leading to two new phases He2(HF)4 and He(HF).With coplanar(HF)_(4)rings,He_(2)(HF)_(4)have an aromaticity-like electronic behavior while He(HF)has a new type of chiral HF chain.The formation of He_(2)(HF)_(4)and He(HF)prove that the chemical pressure from He,on par with external pressure,have ability to control the structural and electronic configuration and induce some new familiars of compounds include H and He elements which are fundamental planetary materials in giant planets.

Investigation and Landscape Application of Euphorbiaceae Plant Resources in Sanling Mountain Forest Park

This study was conducted to investigate and analyze Euphorbiaceae plant resources in Sanling Mountain Forest Park in Zhanjiang City,Guangdong Province.A plant resource development and utilization value evaluation system was established by analytic hierarchy process(AHP)and used to comprehensively evaluate the development and utilization value of Euphorbiaceae plant resources in the area.The results showed that the comprehensive evaluation values of Sapium discolor,Sapium sebiferum,Flueggea virosa,Baccaurea ramiflora,Aleurites moluccana,Antidesma ghaesembilla,Phyllanthus emblica and Pedilanthus tithymaloides were greater than 2.65,performing well;the comprehensive evaluation values of Bridelia tomentosa,Glochidion puberum,Breynia fruticosa,Mallotus paniculatus,Mallotus repandus,Mallotus apelta and Alchornea trewioides were in the range of 1.9622-2.5964,performing ordinary;and the comprehensive evaluation values of Phyllanthus reticulatus,Ricinus communis,Croton crassifolius,and Sebastiania chamaelea were smaller than 1.96,which were relatively lower.S.discolor,S.sebiferum,F.virosa,B.ramiflora,A.moluccana,A.ghaesembilla,P.emblica and P.tithymaloides have great development value and can be developed and used in a planned and step-by-step manner,and Aporosa dioica and Euphorbia tirucalli with a lower comprehensive evaluation value but strong stress resistance and adaptability can be applied to the construction of ecological forests and shelter forests.

High-precision nondestructive evaluation of a thermal barrier coating based on perovskite quantum dot anion exchange

Thermal barrier coatings(TBCs)in gas turbine engines are used in expressly harsh environments;thus,assessing TBC integrity status is critical for safety and reliability.However,traditional periodic maintenance involves visual inspections of the TBCs,requiring the gas turbine to be decommissioned and partially dismantled.Most importantly,tiny defects or internal damages that easily cause coating failure cannot be identified.In this work,a new nondestructive evaluation(NDE)technique of TBCs based on quantum dot(QD)anion exchange is first explored internationally.By exchanging anions between the Cl ions and the CsPbBr_(3) QDs,the degrees of salt corrosion of the TBCs are evaluated.The resultant NDE technique shows that the colour of the TBCs obviously changes from green to blue,accompanied by a large blueshift(~100 nm)of the photoluminescence(PL)peak position.In addition,the relationship between the PL peak position and coating thermophysical properties indicates that the precision of this NDE technique may easily identify theμm-level of the thermal growth oxide(TGO)changes inside the TBCs.

装配水平筛板的气升式反应器中气液传质特性的数值模拟

利用Turbulent–Lehr组合模型对装配水平筛板的气升式反应器进行了计算流体力学(CFD)模拟,研究水平筛板对气含率、气泡直径、体积传质系数(kLa)和气液流速的影响。结果表明,筛板对气相的囤积作用和对液相的阻碍作用增加了反应器的整体气含率。筛板对气相的二次均布作用减弱了筛板和液面之间区域的气泡聚并过程,筛板筛孔对气泡的破碎作用产生了大量小于初始直径的气泡,增加了气泡比表面积(a);筛板对液相的阻碍作用提高了筛板附近的气–液相流动速度差,从而提高了该区域的液膜传质系数(kL),强化了反应器内的气液传质效果。

Distributed Scheduling Problems in Intelligent Manufacturing Systems

Currently,manufacturing enterprises face increasingly fierce market competition due to the various demands of customers and the rapid development of economic globalization.Hence,they have to extend their production mode into distributed environments and establish multiple factories in various geographical locations.Nowadays,distributed manufacturing systems have been widely adopted in industrial production processes.In recent years,many studies have been done on the modeling and optimization of distributed scheduling problems.This work provides a literature review on distributed scheduling problems in intelligent manufacturing systems.By summarizing and evaluating existing studies on distributed scheduling problems,we analyze the achievements and current research status in this field and discuss ongoing studies.Insights regarding prior works are discussed to uncover future research directions,particularly swarm intelligence and evolutionary algorithms,which are used for managing distributed scheduling problems in manufacturing systems.This work focuses on journal papers discovered using Google Scholar.After reviewing the papers,in this work,we discuss the research trends of distributed scheduling problems and point out some directions for future studies.

Alignment error modeling and control of a double-sided microlens array during precision glass molding

Double-sided microlens arrays(DSMLAs)include combinations of two single-sided MLAs to overcome positioning errors and greatly improve light transmissivity compared to other types of lenses.Precision glass molding(PGM)is used to fabricate DSMLAs,but controlling alignment errors during this process is challenging.In this paper,a mold assembly was manufactured with a novel combination of materials to improve the alignment accuracy of mold cores during PGM by using the nonlinear thermal expansion characteristics of the various materials to improve the DSMLA alignment accuracy.By establishing a mathematical model of the DSMLA alignment error and a thermal expansion model of the mold-sleeve pair,the relationship between the maximum alignment error of the DSMLA and the mold-sleeve gap was determined.This research provides a method to optimize the mold-sleeve gap and minimize the alignment error of the DSMLA.The measured DSMLA alignment error was 10.56μm,which is similar to the predicted maximum alignment error.Optical measurements showed that the uniformity of the homogenized beam spot was 97.81%,and the effective homogeneous area accounted for 91.66%of the total area.This proposed method provides a novel strategy to improve the performance of DSMLAs.