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Microstructural evolution of Al-Cu-Li alloys with different Li contents by coupling of near-rapid solidification and two-stage homogenization treatment

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China Foundry 2020年第3期17卷 190-197页

作者： Lei luo Liang-shun luo Zhi-ping Li hong-ying Xia Yan-qing Su Liang Wang Jing-jie Guo Heng-zhi Fu School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Microstructural improvement of Al-Cu-Li alloys with high Li content plays a critical role for the acquisition of excellent mechanical properties and ultra-low *** this regard,the Al-Cu-Li alloy castings with high Li content from 1.5 wt.%to 4.5 wt.%were prepared by near-rapid solidification,followed by two-stage homogenization treatment(490℃/16 h and 530℃/16 h).The microstructural evolution and solidification behavior of the as-cast and homogenized alloys with different Li contents were systematically studied by combining experiments with calculations by Pandat *** results indicate that with the increase of Li content,the grain sizes decrease,the solution ability of Cu in the matrixα-Al phase increases,while the content of secondary dendrites increases and the precipitated phases change from low melting point phases to high melting point phases under the near-rapid ***,by the coupling of near-rapid solidification and two-stage homogenization,the metastable precipitated phases(Al7Cu4Li and AlCu3)can be dissolved effectively in the alloys with Li content of 1.5 wt.%-2.5 wt.%;moreover,the stable precipitated phases(Al6CuLi3 and Al2CuLi)uniformly distribute at the grain boundaries in the alloys with Li content of 3.5 wt.%-4.5 wt.%.As a result,the refined and homogenized microstructure can be obtained.

关键词： Al-Cu-Li alloys ultra-low density near-rapid solidification two-stage homogenization treatment microstructural evolution

Shear behavior of two-order morphology in rock joints

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Journal of Mountain Science 2023年第3期20卷 845-858页

作者： HUANG Man CHEN Xuan-nan hong Chen-jie LIU Dan luo Zhan-you DU Shi-gui WU Zao-sheng Dept.of Civil Engineering Shaoxing UniversityShaoxing 312000China State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Civil and Environmental Engineering Ningbo UniversityNingbo 315000China Geological Survey Engineering Department Shaoxing Huahui Engineering Design Group Co.LTDShaoxing 312000China

Two-order morphology of rock joints named as waviness and unevenness can be separated by morphology classification method,which plays a decisive role in the evolution of shear stress during the shear *** joint morphology is obtained by using 3D printing and 3D laser scanning techniques and the joint model samples in two-order morphology are produced by cement ***,shear tests are performed under different normal *** shows that the waviness is dominant in the total morphology during the shear test,and the shear contribution of unevenness mainly occurs in the climbing phase of shearing *** the failure modes of two-order morphology,waviness mainly embodies shear dilation characteristics and unevenness mainly shows shear wear *** on this,a quantitative parameter is proposed to represent the ratio of the peak shear strength of the two-order morphology to that of total *** functional relationship between the peak shear strength of total and two-order morphologies is determined,providing a theoretical method for further in-depth study on the shear strength of the interaction with two-order morphology of rock joints.

关键词： Rock joints Two-order morphology Shearcharacteristics S hear strength Damage mechanism

Monte Carlo Simulation-Based Robust Workflow Scheduling for Spot Instances in Cloud Environments

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Tsinghua Science and Technology 2024年第1期29卷 112-126页

作者： Quanwang Wu Jianzhao Fang jie Zeng Junhao Wen Fengji luo College of Computer Science Chongqing UniversityChongqing 400044China National Experimental Teaching Demonstration Center Chongqing UniversityChongqing 400044China College of Big Data and Software Engineering Chongqing UniversityChongqing 400044China School of Civil Engineering The University of SydneySydney 2006Australia

When deploying workflows in cloud environments,the use of Spot Instances(SIs)is intriguing as they are much cheaper than on-demand ***,Sls are volatile and may be revoked at any time,which results in a more challenging scheduling problem involving execution interruption and hence hinders the successful handling of conventional cloud workflow scheduling *** some scheduling methods for Sls have been proposed,most of them are no more applicable to the latest Sls,as they have evolved by eliminating bidding and simplifying the pricing *** study focuses on how to minimize the execution cost with a deadline constraint when deploying a workflow on volatile Sls in cloud *** on Monte Carlo simulation and list scheduling,a stochastic scheduling method called MCLS is devised to optimize a utility function introduced for this *** the Monte Carlo simulation framework,MCLS employs sampled task execution time to build solutions via deadline distribution and list scheduling,and then returns the most robust solution from all the candidates with a specific evaluation mechanism and selection *** results show that the performance of MCLS is more competitive comparedwithtraditionalalgorithms.

关键词： constrained optimization Monte Carlo simulation robustness Spot Instances(Sls) workflow scheduling

Revealing effect of Al content on oxidation of novel Co-Cr-Nb-W carbide-strengthened superalloy

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Rare Metals 2024年第9期43卷 4521-4534页

作者： Chen Ling Shang-Ping Li jie Hou He-Li luo Central Iron&Steel Research Institute Beijing 100081China Beijing GAONA Materials&Technology Co. Ltd.Beijing 100081China

The high-temperature oxidation behavior of novel Co-Cr-Nb-W carbide-strengthened wear-resistance alloys with different Al contents(1wt%,2wt%and 3wt%)at 950,1000 and 1050℃was thoroughly investigated by scanning electron microscopy,X-ray diffraction,X-ray photoelectron spectroscopy and field emission electron probe *** porous property of NbC in-situ oxidation products(Nb_(2)O_(5),Co Nb_(2)O_(6)and Co_(4)Nb_(2)O_(9))induces a multi-layered oxide scale with micropores and ***-Cr-Nb-W alloy with 1 wt%Al undergoes catastrophic oxidation and spalling above 1000℃.The outward transportation of Cr and Co is effectively restrained by a continuous Al_(2)O_(3)scale formed around NbC in-situ oxidation region when Al content reaches 3 wt%.The β-Co Al in Co-Cr-Nb-W alloy with 3 wt%Al has an oxidation priority over eutectic carbides and the alloy matrix which are both enriched with Cr,thereby preventing the formation of Cr-depletion area and improving the self-healing ability of the oxide film.A slight change in Al content has a remarkable influence on the cooperative effect of Al and Cr and multiplies the antioxidant capacity of Co-Cr-Nb-W alloy above 1000℃.

关键词： High-temperature oxidation behavior Oxidation kinetics Superalloy Wear-resistant alloy Microstructure

Quality assessment in competition-based software crowdsourcing

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Frontiers of Computer Science 2020年第6期14卷 17-30页

作者： Zhenghui HU Wenjun WU jie luo Xin WANG Boshu LI State Key Laboratory of Software Development Environment Beihang UniversityBeijing 100191China

Quality assessment is a critical component incrowdsourcing-based software engineering(CBSE)as soft-ware products arc developed by the crowd with unknownor varied skills and *** this *** proposea novel metric called the project score to measure the perfor-mance of projects and the quality of products for compctition-based software crowdsourcing devclopment(CBSCD)*** the best of our knowledge,this is the first work to deal with the quality issue of CBSE in the perspective ofprojccts instead of *** particular,we develop a hi-crarchical quality evaluation framework for CBSCD projects and come up with two metric aggregatibn modcls for *** first model is a modified squale model that canlocate the sofiware modules of poor quality,and the secondone is a clustering-based aggregation model,which takes dif-ferent impacts of phases into *** test the effective-ness of the proposed *** conduct an empirical studyon TopCoder,which is a famous CBSCD *** that the proposed project score is a strong indicator ofthe performance and product quality of CBSCD *** find that the clustering-based aggregation model outpcr-forms the Squale one by increasing the percentage of the per-formance evaluation criterion of aggregation models by anadditional 29%.Our approach to quality assessment for CB-sCD projects could potentially facilitate software managersto assess the overall quality of a crowdsourced project con-sisting of programming contests.

关键词： crowdsourcing software engineering.productquality.competition evaluation framework metric aggregation

Optimizing Polynomial-Time Solutions to a Network Weighted Vertex Cover Game

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IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 512-523页

作者： jie Chen Kaiyi luo Changbing Tang Zhao Zhang Xiang Li the Adaptive Networks and Control Laboratory Department of Electronic EngineeringFudan UniversityShanghai 200433China the College of Mathematics and Computer Science Zhejiang Normal UniversityJinhua 321004 Yuxi Middle School Taizhou 317399China IEEE the College of Physics and Electronics Information Engineering Zhejiang Normal UniversityJinhua 321004China the College of Mathematics and Computer Science Zhejiang Normal UniversityJinhua 321004China the Adaptive Networks and Control Laboratory Department of Electronic EngineeringFudan UniversityShanghai 200433 the Institute of Complex Networks and Intelligent Systems Shanghai Research Institute for Intelligent Autonomous SystemsTongji UniversityShanghai 201210China

Weighted vertex cover(WVC)is one of the most important combinatorial optimization *** this paper,we provide a new game optimization to achieve efficiency and time of solutions for the WVC problem of weighted *** first model the WVC problem as a general game on weighted *** the framework of a game,we newly define several cover states to describe the WVC ***,we reveal the relationship among these cover states of the weighted network and the strict Nash equilibriums(SNEs)of the ***,we propose a game-based asynchronous algorithm(GAA),which can theoretically guarantee that all cover states of vertices converging in an SNE with polynomial ***,we improve the GAA by adding 2-hop and 3-hop adjustment mechanisms,termed the improved game-based asynchronous algorithm(IGAA),in which we prove that it can obtain a better solution to the WVC problem than using a the ***,numerical simulations demonstrate that the proposed IGAA can obtain a better approximate solution in promising computation time compared with the existing representative algorithms.

关键词： Game-based asynchronous algorithm(GAA) game optimization polynomial time strict Nash equilibrium(SNE) weighted vertex cover(WVC)

Silent information regulator sirtuin 1 ameliorates acute liver failure via the p53/glutathione peroxidase 4/gasdermin D axis

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World Journal of Gastroenterology 2024年第11期30卷 1588-1608页

作者： Xing-Nian Zhou Quan Zhang hong Peng Yu-jie Qin Yu-hong Liu Lu Wang Ming-Liang Cheng Xin-Hua luo hong Li Department of Infectious Diseases The Affiliated Hospital of Guizhou Medical UniversityGuizhou Medical UniversityGuiyang 550004Guizhou ProvinceChina Department of Infectious Diseases Guizhou Provincial People's HospitalGuiyang 550001Guizhou ProvinceChina

BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and *** silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and *** To investigate the association between ferroptosis and pyroptosis and the upstream regulatory *** This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce *** D(GSDMD)^(-/-)mice were used as an experimental *** changes in liver tissue were monitored by hematoxylin and eosin ***,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial ***-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain ***1,p53,and GSDMD were assessed by immunofluorescence *** Serum AST and ALT levels were elevated in patients with ***1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver *** the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was *** mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were *** vitro,knockdown of p53 and overexpression of GPX

关键词： Silent information regulator sirtuin 1 Ferroptosis Pyroptosis p53/glutathione peroxidase 4/gasdermin D Acute liver failure

Effects of plant diversity on greenhouse gas emissions in microcosms simulating vertical constructed wetlands with high ammonium loading

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Journal of Environmental Sciences 2019年第3期31卷 229-237页

作者： Wenjuan Han Guiying luo Bin luo Chenchen Yu Hai Wang jie Chang Ying Ge College of Life Sciences Zhejiang University College of Chemistry and Life Sciences Zhejiang Normal University College of Life Sciences Shaoxing University

Wastewater with relatively high nitrogen concentrations is a major source of nitrous oxide(N_2O) and methane(CH_4) emissions and exerts multiple stresses on the *** have shown that plant diversity plays an important role in ecosystem ***, the effects of plant species diversity on CH_4 and N_2O emissions under high ammonium(NH_4^+-N) loading rates remain unclear. In this study, a microcosm experiment simulating vertical constructed wetlands supplied with high NH_4^+-N water levels was established. The treatments included four species richness levels(1, 2, 3, 4) and 15 species compositions. There was no significant relationship between species richness and N_2O emissions. However, N_2O emissions were significantly reduced by specific plant species composition. Notably, the communities with the presence of Rumex japonicus L. reduced N_2O emissions by 62% compared to communities without this species. This reduction in N_2O emissions may have been a result of decreased N concentrations and increased plant biomass. CH_4 emissions did not respond to plant species richness or species ***, plant species identity surpassed species richness in lowering N_2O emissions from constructed wetlands with high NH_4^+-N water. The results also suggest that communities with R. japonicus could achieve higher N removal and lower greenhouse gas emissions than other wetland species.

关键词： Plant species richness Species identity Methane Nitrous oxide Nitrogen removal Ecosystem functioning

Impact of Kuroshio Extension dipole mode variability on the North Pacific storm track

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Atmospheric and Oceanic Science Letters 2017年第5期10卷 389-396页

作者： ZHANG jie luo De-Hai Key Laboratory of Regional Climate–Environment for East Asia Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences

An index of a large-scale Kuroshio Extension（KE） sea surface height dipole（KED） mode is constructed using satellite altimeter sea level anomaly observations from January 1993 to December 2015 based on previous work of the second author. It is found that the KED mode that undergoes a decadal variation from a negative phase（a positive-over-negative dipole, KED.） to a positive phase（a negative-over-positive dipole, KED＋） can affect the variability of the oceanic SST front and the North Pacific storm track. The results show that the oceanic SST fronts in the north of the KE region and in the KE region — referred to as the NSST and KSST fronts, respectively — are closely correlated with the KED mode. In the NSST front region, the SST front is stronger for KED. than for KED＋, and the opposite is the case in the KSST region. It is further revealed that the decadal phase transition of the KED mode can change the location and strength of the North Pacific storm track, with the North Pacific storm track being slightly weaker and moving more northwards as a whole during the KED. mode than during the KED＋ mode. The westerly wind associated with the storm track on the downstream side of the KE region intensifies and shifts northwards under KED. compared to KED＋.Furthermore, the transition of the KED mode gives rise to changes in the North Pacific storm track by changing the NSST and KSST fronts and meridional heat flux.

关键词： Kuroshio Extension oceanic front North Pacific storm track