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Dynamic recrystallization mechanism, texture evolution development and mechanical characteristics of a Mg–8.7Gd–4.18Y–0.42Zr magnesium alloy by ECAP

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Progress in Natural Science:Materials international 2024年第02期34卷 376-388页

作者： ling zhang Yinglong li School of Materials Science and Engineering Northeastern University School of Mechanical and Engineering Ningxia Institute of Science and Technology

Equal channel angle pressing is recognized for.its ability to refine alloy gr.ins and alter gr.in orientation, thereby achieve better mechanical performance of the magnesium alloy. This study investigates the microstructures,dynamic recrystallization mechanism, texture development, and mechanical performance of GW94K(Mg–8.7Gd–4.18Y–0.42Zr wt. %) Mg alloy following ECAP-4 passes at 400°C and 3 mm/min. results show that when high-temperature deformation is undertaken, twin formation is suppressed while dislocation slip is facilitated, increasing dislocation density during deformation. Following ECAP deformation, the sample displayed higher fracture elongation, TYS, and UTS than the as-solutioned GW94K alloy. in par.icular, the GW94K alloy performed well mechanically after ECAP-4 passes, with an ultimate TYS of 231 MPa, an UTS of 290 MPa, and an elongation of 14.8 %. DDrX and shear bands induce CDrX, both of which are important in plastic deformation. as well as in modifying microstructure and gr.in orientation during ECAP deformation.

关键词： Equal channel angular pressing Dynamic recrystallization mechanism Mechanical performance Mg-Gd-Y-Zr alloy Magnesium alloy Texture development

Guidance strategy of motion camouflage for spacecraft pursuit-evasion game

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Chinese Journal of Aeronautics 2024年第3期37卷 312-319页

作者： Jianqing li Chaoyong li Yonghe zhang Space information research institute Hangzhou Dianzi UniversityHangzhou 310018China College of Electrical Engineering Zhejiang UniversityHangzhou 310027China Key Lab of Microsatellites Chinese Academy of SciencesShanghai 201210China

This work is inspired by a stealth pursuit behavior called motion camouflage whereby a pursuer approaches an evader while the pursuer camouflages itself against a predeter.ined *** formulate the spacecraft pursuit-evasion problem as a stealth pursuit strategy of motion camouflage,in which the pursuer tries to minimize a motion camouflage index defined in this *** Euler-Hill reference frame whose origin is set on the circular reference or.it is used to describe the *** on the rule of motion camouflage,a guidance strategy in open-loop form to achieve motion camouflage index is derived in which the pursuer lies on the camouflage constr.int line connecting the central spacecraft and *** order to dispose of the dependence on the evader acceleration in the open-loop guidance strategy,we further consider the motion camouflage pursuit problem within an infinite-horizon nonlinear quadratic differential *** saddle point solution to the game is derived by using the state-dependent riccati equation method,and the resulting closed-loop guidance strategy is effective in achieving motion *** are performed to demonstrate the capabilities of the proposed guidance strategies for the pursuit–evasion game scenario.

关键词： Pursuit-evasion problem Motion camouflage Differential game Guidance strategy Or.it control

Phosphorylation Promotes the Accumulation of PEriOD Protein Foci

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research 2024年第1期2023卷 59-69页

作者： Mengna li Shujing li Luoying zhang Key Laboratory of Molecular Biophysics of Ministry of Education College of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanHubei 430074China Department of life Sciences Bengbu Medical CollegeBengbuAnhui 233030China Hubei Province Key Laboratory of Oral and Maxillofacial Development and regeneration WuhanHubei 430022China

Circadian clock drives the 24-h rhythm in our behavior and *** molecular clock consists of a series of transcriptional/translational feedback loops operated by a number of clock genes.A very recent study reported that the clock protein PEriOD(PEr.is organized into discrete foci at the nuclear envelope in fly circadian neurons,which is believed to be important for controlling the subcellular localization of clock *** of inner nuclear membrane protein lamin B receptor(LBr)leads to disruption of these foci,but how they are regulated is yet ***,we found that PEr foci are likely phase-separated condensates,the formation of which is mediated by intrinsically disordered region in *** promotes the accumulation of these *** phosphatase 2A,which is known to dephosphorylate PEr,hampers the accumulation of the *** the other hand,the circadian kinase DOUBLETiME(DBT)which phosphorylates PEr enhances the accumulation of the *** likely facilitates PEr foci accumulation by destabilizing the catalytic subunit of protein phosphatase 2A,MiCrOTUBULE STAr(MTS).in conclusion,here,we demonstrate a key role for phosphorylation in promoting the accumulation of PEr foci,while LBr modulates this process by impinging on the circadian phosphatase MTS.

关键词： conclusion separated translational

Strategies of selective electroreduction of aqueous nitrate to N_(2) in chloride-free system:A critical review

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Green Energy & Environment 2024年第2期9卷 198-216页

作者： Fukuan li Weizhe zhang Peng zhang Ao Gong Kexun li College of Environmental Science and Engineering Nankai UniversityTianjin300350China MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai UniversityTianjin300350China

Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for conver.ing nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or.into value-added ammonia from the perspective of electrocatalytic NH_(3) *** reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) ***,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several *** this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,*** summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are ***,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.

关键词： Nitrate Chloride Electroreduction Selectivity Nitrogen

Migration time prediction and assessment of toxic fumes under forced ventilation in underground mines

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Underground Space 2024年第5期18卷 273-294页

作者： Jinr.i zhang Tingting zhang Chuanqi li School of resources&Civil Engineering Northeastern UniversityShenyang 110819China Laboratory 3Sr CNRS UMR 5521Grenoble Alpes UniversityGrenoble 38000France

This study aims to predict the migration time of toxic fumes induced by excavation blasting in underground *** reduce numerical simulation time and optimize ventilation design,several back propagation neural network(BPNN)models optimized by honey badger algorithm(HBA)with four chaos mapping(CM)functions(i.e.,Chebyshev(Che)map,Circle(Cir)map,Logistic(Log)map,and Piecewise(Pie)map)are developed to predict the migration time.125 simulations by the computational fluid dynamics(CFD)method are used to tr.in and test the developed *** deter.ination coefficient(r2),the variance accounted for(VAF),the Willmott’s index(Wi),the root mean square error(rMSE),the mean absolute percentage error(MAPE),and the sum of squares error(SSE)are utilized to evaluate the model *** evaluation results indicate that the CirHBA-BPNN model has achieved the most satisfactory performance by reaching the highest values of r2(0.9945),Wi(0.9986),VAF(99.4811%),and the lowest values of rMSE(15.7600),MAPE(0.0343)and SSE(6209.4),*** wind velocity in roadway(Wv)is the most important feature for predicting the migration time of toxic ***,the intrinsic response characteristic of the optimal model is implemented to enhance the model interpretability and provide reference for the relationship between features and migration time of toxic fumes in ventilation design.

关键词： Migration time Underground mines Honey badger algorithm Chaos mapping Back propagation neural network

Effects of mid-passage gap with a variable surface angle on a tur.ine vane endwall’s aerothermal and film cooling performances

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Chinese Journal of Aeronautics 2024年第6期37卷 20-37页

作者： Zhiyu li Kaiyuan zhang Zhigang li Jun li institute of Turbomachinery Xi’an Jiaotong UniversityXi’an 710049China

The mid-passage gap is an inevitable structure in a vane passage due to tur.ine vanes being manufactured *** coolant from this gap is able to prevent hot mainstream ingression and provide cooling protection for the endwall.A novel idea of enlar.ing the endwall’s coverage area and reducing the endwall’s thermal load by applying the mid-passage gap with variable surface angles is car.ied out in this *** endwall’s aerothermal and film cooling performances under four mid-passage gap modes at three typical mass flow ratio conditions are numerically *** indicate that under the traditional mid-passage mode,the coolant flows into the mainstream with a perpendicular.incidence angle and can’t stick to the ***,cooling failure occurs,and the endwall’s thermal load is badly *** film cooling level at the suction-side endwall is improved when applying the mid-passage gap of a 45surface angle due to the secondary vortex being *** addition,when applying the mid-passage gap of a 135surface angle,the horseshoe vortex is pushed away,and the coverage area at the pressure-side endwall is enlarged *** best film cooling performance is achieved when the upstream surface angle is 135and the downstream surface angle is 45due to the adiabatic film cooling effectiveness being increased at both the pressure-and suction-side *** the mass flow ratio is 1.5%,the coverage area is enlarged by 43%,and the area-averaged adiabatic film cooling effectiveness is increased by 37%,when compared with those under the traditional mid-passage mode.

关键词： Film cooling Heat transfer Surface angle Mid-passagegap Tur.inevane endwall

Theoretical Analysis of Cooperative Driving at idealized Unsignalized intersections

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Tsinghua Science and Technology 2024年第1期29卷 257-270页

作者： Shen li Jiawei zhang Zhenwu Chen li li Department of Civil Engineering Tsinghua UniversityBeijing 100084China Department of Automation Tsinghua UniversityBeijing 100084China Shenzhen Urban Transport Planning Center Co. Ltd.Shenzhen 518000China

Cooperative driving is widely viewed as a promising method to better utilize limited road resources and alleviate traffic *** recent years,several cooperative driving approaches for.idealized traffic scenarios(i.e.,uniform vehicle ar.ivals,lengths,and speeds)have been ***,theoretical analyses and comparisons of these approaches are *** this study,we propose a unified group-by-group zipper-style movement model to describe different approaches synthetically and evaluate their *** derive the maximum throughput for cooperative driving plans of idealized unsignalized intersections and discuss how to minimize the delay of *** obtained conclusions shed light on future cooperative driving studies.

关键词： cooperative driving connected and automated vehicles unsignalized intersection

Nanoscale Zero-Valent iron(nZVi)for Heavy Metal Wastewater Treatment:A Perspective

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Engineering 2024年第5期36卷 16-20页

作者： Shaolin li Lei li Weixian zhang State Key Laboratory for Pollution Control and resource reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai institute of Pollution Control and Ecological Security Shanghai 200092China

industries such as non-ferrous metal smelting discharge billions of gallons of highly toxic heavy metal wastewater(HMW)worldwide annually,posing a severe challenge to conventional wastewater treatment plants and har.ing the *** is traditionally treated via chemical precipitation using lime,caustic,or sulfide,but the effluents do not meet the increasingly stringent discharge *** issue has spurred an increase in research and the development of innovative treatment technologies,among which those using nanopar.icles receive par.icular *** such initiatives,treatment using nanoscale zero-valent iron(nZVi)is one of the best *** nZVi is already well known for.its site-remediation use,this perspective highlights its application in HMW treatment with metal *** demonstrate several advantages of nZVi in this wastewater application,including its multifunctionality in sequestrating a wide array of metal(loid)s(>30 species);its capability to capture and enrich metal(loid)s at low concentrations(with a removal capacity reaching 500 mg·g^(-1)nZVi);and its operational convenience due to its unique *** these advantages are attributable to nZVi’s diminutive nanopar.icle size and/or.its unique iron *** also present the first engineering practice of this application,which has treated millions of cubic meters of HMW and recovered tons of valuable metals(e.g.,Cu and Au).it is concluded that nZVi is a potent reagent for treating HMW and that nZVi technology provides an eco-solution to this toxic waste.

关键词： Nanoscale zero-valent iron Wastewater Heavy metal resource recovery

False Negative Sample Detection for Graph Contrastive Lear.ing

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Tsinghua Science and Technology 2024年第2期29卷 529-542页

作者： Binbin zhang li Wang College of Data Science Taiyuan University of TechnologyJinzhong 030600China

recently,self-super.ised lear.ing has shown great potential in Graph Neural Networks (GNNs) through contrastive lear.ing,which aims to learn discriminative features for each node without label information. The key to graph contrastive lear.ing is data augmentation. The anchor node regards its augmented samples as positive samples,and the rest of the samples are regarded as negative samples,some of which may be positive samples. We call these mislabeled samples as “false negative” samples,which will seriously affect the final lear.ing effect. Since such semantically similar samples are ubiquitous in the graph,the problem of false negative samples is very significant. To address this issue,the paper proposes a novel model,False negative sample Detection for Graph Contrastive Lear.ing (FD4GCL),which uses attribute and structure-aware to detect false negative samples. Experimental results on seven datasets show that FD4GCL outperforms the state-of-the-art baselines and even exceeds several super.ised methods.

关键词： graph representation lear.ing contrastive lear.ing false negative sample detection