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High-Temperature Stability of Mg-1Al-12Y Alloy Containing LPSO Phase and Mechanism of Its Portevin-Le Chatelier(PLC)Effect

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Acta Metallurgica Sinica(English Letters) 2024年第6期37卷 982-998页

作者： Qian-Long ren Shuai Yuan Shi-Yu Luan Jin-Hui Wang Xiao-wei Li Xiao-Yu Liu Qinghai Provincial Key Laboratory of New Light Alloys Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and FormingQinghai UniversityXining810016China School of Materials Science and Engineering Shenyang University of TechnologyShenyang110870China

In this study,the high-temperature stability and the generation mechanism of the Portevin-Le Chatelier(PLC)effect in solid-solution Mg-1Al-12Y alloy with different heat treatment processes were investigated by adjusting the content of long-period stacking ordered(LPSO)*** was found that the content of LPSO phases in the alloys differed the most after heat treatment at 530℃for 16 h and 24 h,with values of 13.56%and 3.93%***,high-temperature tensile experiments were conducted on these two alloys at temperatures of 150℃,200℃,250℃,and 300℃.The results showed that both alloys exhibited the PLC effect at temperatures ranging from 150 to 250℃.However,at a temperature 300℃,only the alloy with a greater concentration of LPSO phases exhibited the PLC effect,whereas the alloy with a lower proportion of LPSO phases did not exhibit this ***,both alloys exhibited remarkable high-temperature stability,with the alloy containing a greater percentage of LPSO phases also demonstrating superior *** underlying mechanism for this phenomenon lies in the exceptional high-temperature stability exhibited by the second phase within the ***,the LPSO phase effectively obstructs the movement of dislocations,and it also undergoing kinking to facilitate plastic deformation of the *** results indicate that the PLC effect can be suppressed by reducing dislocation pile-up at grain boundaries,which leads to a decrease in alloy plasticity but an increase in *** presence of the PLC effect in the WA121 alloy is attributed to the abundant dispersed second phase within the alloy,which initially hinders the movement of dislocations,leading to an increase in stress,and subsequently releases the dislocations,allowing them to continue their movement and thereby reducing in stress.

关键词： Magnesium alloy Long-period stacking ordered(LPSO)phase Portevin-Le Chatelier effect High temperature

Pollen-expressed RLCKs control pollen tube burst

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Plant Communications 2024年第8期5卷 147-156页

作者： Yin-Jiao Xu Ting Luo Peng-min Zhou wei-Qi Wang wei-Cai Yang Hong-Ju Li Center for Developmental Biology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijing 100101China Center for Molecular Agrobiology Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijingChina Key Laboratory of Seed Innovation Institute of Genetics and Developmental BiologyChinese Academy of SciencesBeijingChina

In angiosperms,the pollen tube enters the receptive synergid cell,where it ruptures to release its cytoplasm along with two sperm *** interaction is complex,and the exact signal transducers that trigger the bursting of pollen tubes are not well *** this study,we identify three homologous receptor-like cytoplasmic kinases(RLCKs)expressed in pollen tubes of Arabidopsis,Delayed Burst 1/2/3(DEB1/2/3),which play a crucial role in this *** genes produce proteins localized on the plasma membrane,and their knockout causes delayed pollen tube burst and entrance of additional pollen tubes into the embryo sac due to fertilization *** show that DEBs interact with the Ca^(2+)pump ACA9,influencing the dynamics of cytoplasmic Ca^(2+)in pollen tubes through *** results highlight the importance of DEBs as key signal transducers and the critical function of the DEB-ACA9 axis in timely pollen tube burst in synergids.

关键词： Pollen tube burst RLCKs Calcium signaling/transport Double fertilization

Joint UAV trajectory and communication design with heterogeneous multi-agent reinforcement learning

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Science China(Information Sciences) 2024年第3期67卷 225-245页

作者： Xuanhan ZHOU Jun XIONG Haitao ZHAO Xiaoran LIU Baoquan ren Xiaochen ZHANG Jibo wei Hao YIN College of Electronic Science and Technology National University of Defense Technology Systems Engineering Institute Academy of Military Sciences PLA

Unmanned aerial vehicles(UAVs) are recognized as effective means for delivering emergency communication services when terrestrial infrastructures are unavailable. This paper investigates a multiUAV-assisted communication system, where we jointly optimize UAVs’ trajectories, user association, and ground users(GUs)’ transmit power to maximize a defined fairness-weighted throughput metric. Owing to the dynamic nature of UAVs, this problem has to be solved in real time. However, the problem’s non-convex and combinatorial attributes pose challenges for conventional optimization-based algorithms, particularly in scenarios without central controllers. To address this issue, we propose a multi-agent deep reinforcement learning(MADRL) approach to provide distributed and online solutions. In contrast to previous MADRLbased methods considering only UAV agents, we model UAVs and GUs as heterogeneous agents sharing a common objective. Specifically, UAVs are tasked with optimizing their trajectories, while GUs are responsible for selecting a UAV for association and determining a transmit power level. To learn policies for these heterogeneous agents, we design a heterogeneous coordinated QMIX(HC-QMIX) algorithm to train local Q-networks in a centralized manner. With these well-trained local Q-networks, UAVs and GUs can make individual decisions based on their local observations. Extensive simulation results demonstrate that the proposed algorithm outperforms state-of-the-art benchmarks in terms of total throughput and system fairness.

关键词： unmanned aerial vehicle (UAV) trajectory design resource allocation multi-agent deep reinforcement learning (MADRL) heterogeneous agents

Effect of lanthanum on inclusions in non-oriented electrical steel slabs

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Journal of Iron and Steel Research International 2024年第7期31卷 1680-1691页

作者： Qiang ren Zhi-yuan Hu Yun-xia Liu wei-cheng Zhang Zi-qi Gao Li-feng Zhang School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Research and Development Department Shougang Zhixin Qian'an Electromagnetic Material Co.Ltd.Qian'an 064400HebeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

The effect of lanthanum on the characteristics of inclusions in the slab of non-oriented electrical steels was investigated through industrial trials and thermodynamic *** number,size,and chemical composition of inclusions in the surface,one-quarter of thickness and the center of slabs with and without lanthanum addition were statistically analyzed using an automatic inclusion analysis *** the lanthanum-free slab,inclusions were predominately ***_(2)O_(3),MgO,and AlN as well as a small number of Al_(2)O_(3)-MgO-CaO and *** number densities of oxide inclusions and AlN decreased from the surface to the center of the slab,which was ascribed to the difference in cooling intensity during the continuous *** the steel with lanthanum addition,inclusions were modified into LaAlO_(3) and La_(2)O_(2)S and gradually transformed into dual-phase MgO-La_(2)S3 with an increasing distance from the slab surface due to the reaction between the lanthanum-containing inclusion and the steel *** uneven distribution of oxide inclusions along the thickness of the slab was eliminated in the lanthanum-bearing slab because the dissolved oxygen was remarkably decreased by ***-bearing inclusions were more likely to agglomerate AlN by inducing the heterogeneous nucleation of AlN on their surface,while small-size ***_(2)O_(3) inclusions hardly showed a coarsening effect on the size of AlN.

关键词： Lanthanum-Inclusion Non-oriented electrical steel Aluminum nitride Heterogenous nucleation

Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling

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Petroleum Science 2024年第1期21卷 54-76页

作者： Qi-Qiang ren Jin-Liang Gao Rong-Tao Jiang Jin Wang Meng-Ping Li Jian-wei Feng Institute of Sedimentary Geology Chengdu University of TechnologyChengdu 610059SichuanChina PetroChina Research Institute of Petroleum Exploration and Development Beijing100083China Jianghan Oilfield Oil and Gas Production Capacity Construction Management Center Chongqing408000China Sinopec Chongqing Fuling Shale Gas Exploration and Development Company Chongqing408000China College of Energy Chengdu University of TechnologyChengdu 610059SichuanChina School of Geoscience China University of Petroleum(East China)Qingdao 266580ShandongChina

A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults *** numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation *** study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical *** three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation *** with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben *** the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were *** by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale *** the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly *** junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation *** the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were

关键词： Fault accommodation zone Graben basin Fault activity Tectonic physical simulation experiment Finite element numerical simulation Dongxin fault zone

An integrated minLP model for multi-party coordination in downstream oil supply chain

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Petroleum Science 2024年第3期21卷 2066-2079页

作者： Rui Qiu Bo Zhang wei Zhao ren-Fu Tu Man-Qiu He Qi Liao Yong-Tu Liang National Engineering Laboratory for Pipeline Safety/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum-BeijingFuxue Road No.18Changping DistrictBeijing102249PR China Strategy&Implementation Department PipeChinaDongtucheng Road No.5Chaoyang DistrictBeijing100013PR China

Cooperation among enterprises can bring overall and individual performance improvement,and a smooth coordination method is ***,due to the lack of customized coordination methods,cooperation in the downstream oil supply chain cannot be carried out *** paper intends to propose a multi-party coordination method to promote cooperation between oil shippers and pipeline operator by optimizing oil transportation,oil substitution and pipeline pricing *** integrated game-theoretic modeling and analysis approach is developed to characterize the operation behaviors of all stakeholders in the downstream oil supply *** proposed mixed integer nonlinear programming model constrains supply and demand capacity,transportation routes,oil substitution rules and pipeline freight *** transformation and price discretization are introduced for model linear *** experiments are carried out in the oil distribution system in South *** results show that compared to the business-as-usual scheme,the new scheme saves transportation cost by 3.48%,increases pipeline turnover by 5.7%,and reduces energy consumption and emissions by 7.66%and 6.77%.It is proved that the proposed method improves the revenue of the whole system,achieves fair revenue distribution,and also improves the energy and environmental benefits of the oil supply chain.

关键词： Downstreamoil supplychain Multi-partycoordination Cooperative game Mixed integernonlinear programming model Pipeline transportation Revenue distribution

Strengthening effect of prefabrication(10-12)tensile twinning on AZ80+0.4%Ce magnesium alloy and inhibition mechanism of discontinuous precipitation

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Journal of Magnesium and Alloys 2024年第5期12卷 1918-1930页

作者： Zhen Wang Xi Zhao Zhimin Zhang Yaojin Wu Kai Chen Xianwei ren Dengkui Wang wei Wang School of Mechanical and Electrical Engineering North University of ChinaTaiyuan 030051China Engineering Technology Research Center for Integrated Precision Forming of Shanxi Province North University of ChinaTaiyuan 030051China

This paper provided an effective method to further improve the mechanical properties of the AZ80+0.4%Ce magnesium alloy wheel *** effect of high strength and ductility was obtained with a yield strength of 295.36 MPa,an elongation of 10%,by the combination of pre-deformation(7%deformation)and two-stage aging treatment(120℃/9 h+175℃/24 h).The evolution of the microstructure and properties of the alloy was explored under the coupling conditions of different pre-deformation degrees and multi-stage *** results show that,pre-deformation introduced a large number of(1012)tensile twinning and dislocations,which greatly promoted the probability of continuous precipitates(CPs)*** the contrary,the discontinuous precipitates(DPs)were limited by the vertical and horizontal twin *** a result,the pre-nucleation method of two-stage aging increased the proportion of CPs by 34%-38%.Owing to the DPs was effectively suppressed,the alloy's yield strength has been greatly ***,under multi-stage aging,the twin boundaries induce protruding nucleation to form static recrystallization by hindering the migration of dislocations,and the matrix swallows the twins,then the texture gradually tilts from the two poles to the basal *** an important supplement,the grain refinement and oblique texture promoted the improvement of the yield strength of the component.

关键词： Magnesium alloy Pre-deformed Two-stage aging Tensile twinning Continuous precipitates Texture

Al-modified yolk-shell silica particle-supported NiMo catalysts for ultradeep hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene:Efficient accessibility of active sites and suitable acidity

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Petroleum Science 2024年第1期21卷 654-666页

作者： Ke Yu wei-min Kong Zhen Zhao Ai-Jun Duan Lian Kong Xi-Long Wang State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang 110034LiaoningChina

Yolk-shell SiO2 particles(YP)with center-radial meso-channels were fabricated through a simple and effective ***-containing YP-supported NiMo catalysts with different Al amounts(NiMo/AYP-x,x=Si/Al molar proportion)were prepared and dibenzothiophene(DBT)and 4,6-dimethyl-dibenzothiophene(4,6-DMDBT)were employed as the probes to evaluate the hydrodesulfurization(HDS)catalytic *** as-prepared AYP-x carriers and corresponding catalysts were characterized by some advanced characterizations to obtain deeper correlations between physicochemical properties and the HDS *** average pore sizes of series AYP-x supports are above 6.0 nm,which favors the mass transfer of organic *** cavity between the yolk and the shell is beneficial for the enrichment of S-containing compounds and the accessibility between reactants and active *** embedded into the silica framework could facilitate the formation of Lewis(L)and Brønsted(B)acid sites and adjust the metal-support interaction(MSI).Among all the as-synthesized catalysts,NiMo/AYP-20 catalyst shows the highest HDS *** improved HDS activity of NiMo/AYP-20 catalyst is attributed to the perfect combination of excellent structural properties of the yolk-shell mesoporous silica,enhanced acidity,moderate MSI,and good accessibility/dispersion of active components.

关键词： Al-containing yolk-shell silica particles Accessibility Acidity Metal-support interaction Hydrodesulfurization

A stepwise-responsive editor integrated with three copper ions for the treatment of oral squamous cell carcinoma

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Nano Research 2024年第6期17卷 5424-5434页

作者： Jinna ren Jingying Hu Fan Dong Yan Xu Yang Peng Yuping Qian Guanmeng Zhang min Wang Yuguang Wang Department of Prosthodontics Hospital of StomatologyJilin UniversityChangchun 130021China Department of General Dentistry II Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China Center of Digital Dentistry Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China Department of Nursing Peking University School and Hospital of Stomatology&National Center for Stomatology&National Clinical Research Center for Oral Diseases&National Engineering Research Center of Oral Biomaterials and Digital Medical DevicesBeijing 100081China The VIP Department School and Hospital of StomatologyChina Medical UniversityLiaoning Provincial Key Laboratory of Oral DiseasesShenyang 110002China

Cuprotosis,a new type of cell death,provides great opportunities for the treatment of oral squamous cell carcinoma,as nanocarriers of copper ions can induce cuprotosis and immunogenic ***,we studied an editor that enables production of a nanoparticle“storm”in oral squamous cell carcinoma,maximizing the toxic effect of these particles and reprogramming the tumor microenvironment;as a result,T cells and natural killer(NK)cells can infiltrate the tumor microenvironment to activate an antitumor immune *** this basis,the editor can be combined with optical therapy to improve patient *** this study,the metal ratio was regulated in response to the nanocarrier of acid response ***,in the presence of a specific copper ion content,the nanocarrier could change the permeability of the tumor cell *** on these results,the nanoparticles were cracked in an acidic environment and then released copper ***,the nanoparticles contributed to cuprotosis and immunogenic *** addition,the editor could inhibit murine oral cancer 1(MOC1)tumors in C57BL/6 without *** rate of tumor growth inhibition was as high as approximately 80%.This strategy provides a new idea for ***,it can improve the interaction between immunotherapy and the copper-induced death of oral squamous cell *** all,this study will provide a new opportunity for the effective treatment of oral squamous cell carcinoma.

关键词： cuprotosis immunogenic death photothermal therapy tumor microenvironment immunotherapy