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Effects of orientation on the fatigue crack growth behaviors of the ZK60 magnesium alloy in air and PBS

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Journal of Magnesium and Alloys 2024年第1期12卷 281-294页

作者： Jiaqi Hu zheng liu Zuoliang Ning Hong Gao School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Chemical Process Safety and Equipment Technology Tianjin 300072China

Strong anisotropic corrosion and mechanical properties caused by specimen orientations greatly limit the applications of wrought magnesium *** investigate the influences of specimen orientation,the corrosion tests and(corrosion)fatigue crack growth tests were *** rolled and transverse surfaces of the materials show distinct corrosion rate differences in the stable corrosion stage,but the truth is the opposite for the initial stage of *** air,specimen orientations have a significant influence on the plastic deformation mechanisms near the crack tip,which results in different fatigue fracture surfaces and cracking *** with R-T specimens,N-T specimens show a slower fatigue crack growth(FCG)rate in air,which can be attributed to crack closure effects and deformation twinning near the crack *** corrosion environment will not significantly change the main plastic deformation mechanisms for the same type of ***,the FCG rate in phosphate buffer saline(PBS)is one order of magnitude higher than that in air,which is caused by the combined effects of hydrogen-induced cracking and anodic *** to the similar corrosion rates at crack tips,the specimens with different orientations display close FCG rates in PBS.

关键词： Magnesium alloy Orientation Corrosion Fatigue crack growth

Hybrid stacking ensemble algorithm and simulated annealing optimization for stability evaluation of underground entry-type excavations

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Underground Space 2024年第4期17卷 25-44页

作者： Leilei liu Guoyan Zhao Weizhang Liang zheng Jian School of Resources and Safety Engineering Central South UniversityChangsha 410083China

The stability of underground entry-type excavations(UETEs)is of paramount importance for ensuring the safety of mining *** more engineering cases are accumulated,machine learning(ML)has demonstrated great potential for the stability evaluation of *** this study,a hybrid stacking ensemble method aggregating support vector machine(SVM),k-nearest neighbor(KNN),decision tree(DT),random forest(RF),multilayer perceptron neural network(MLPNN)and extreme gradient boosting(XGBoost)algorithms was proposed to assess the stability of ***,a total of 399 historical cases with two indicators were collected from seven ***,to pursue better evaluation performance,the hyperparameters of base learners(SVM,KNN,DT,RF,MLPNN and XGBoost)and meta learner(MLPNN)were tuned by combining a five-fold cross validation(CV)and simulated annealing(SA)*** on the optimal hyperparameters configuration,the stacking ensemble models were constructed using the training set(75%of the data).Finally,the performance of the proposed approach was evaluated by two global metrics(accuracy and Cohen’s Kappa)and three within-class metrics(macro average of the precision,recall and F1-score)on the test set(25%of the data).In addition,the evaluation results were compared with six base learners optimized by *** hybrid stacking ensemble algorithm achieved better comprehensive performance with the accuracy,Kappa coefficient,macro average of the precision,recall and F1-score were 0.92,0.851,0.885,0.88 and 0.883,*** rock mass rating(RMR)had the most important influence on evaluation ***,the critical span graph(CSG)was updated based on the proposed model,representing a significant improvement compared with the previous *** study can provide valuable guidance for stability analysis and risk management of ***,it is necessary to consider more indicators and collect more extensive and balanced dataset to validate the model in futur

关键词： Underground entry-type excavations(UETEs) Hybrid stacking ensemble Machine learning Simulated annealing Critical span graph Base and meta learners

Data-driven electrical resistance tomography for robotic large-area tactile sensing

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Science China(Information Sciences) 2024年第9期67卷 336-337页

作者： Wendong zheng Huaping liu Xiaofeng liu Fuchun SUN School of Electrical Engineering and Automation Tianjin University of Technology Department of Computer Science and Technology Tsinghua University Key Laboratory of Maritime Intelligent Cyberspace Technology (Hohai University) Ministry of Education

Tactile sensing plays a crucial role in enabling robots to safely interact with objects in dynamic environments [1].Given that potential physical contact can occur at any location during robot interaction, there is a ... 详细信息

关键词： Robot applications

An improved GNSS ambiguity best integer equivariant estimation method with Laplacian distribution for urban low-cost RTK positioning

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Satellite Navigation 2024年第1期5卷 109-124页

作者： ying liu Wanke liu Xiaohong Zhang Yantao Liang Xianlu Tao Liye Ma School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan University129 Luoyu RoadWuhan430079HubeiChina Chinese Antarctic Center of Surveying and Mapping Wuhan University129 Luoyu RoadWuhan430079HubeiChina School of Instrument Science and Engineering Southeast UniversityNanjingJiangsuChina The 54 Research Institute of China Electronics Technology Group CorporationShijiazhuang050081HebeiChina State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081HebeiChina

The integer least squares(ILS)estimation is commonly used for carrier phase ambiguity resolution(AR).More recently,the best integer equivariant(BIE)estimation has also attracted an attention for complex application scenarios,which exhibits higher reliability by a weighted fusion of integer ***,traditional BIE estimation with Gaussian distribution(GBIE)faces challenges in fully utilizing the advantages of BIE for urban low-cost positioning,mainly due to the presence of outliers and unmodeled *** this end,an improved BIE estimation method with Laplacian distribution(LBIE)is proposed,and several key issues are discussed,including the weight function of LBIE,determination of the candidates included based on the OIA test,and derivation of the variance of LBIE solutions for reliability *** results show that the proposed LBIE method has the positioning accuracy similar to the BIE using multivariate t-distribution(TBIE),and significantly outperforms the ILS-PAR and GBIE *** an urban expressway test with a Huawei Mate40 smartphone,the LBIE method has positioning errors of less than 0.5 m in three directions and obtains over 50%improvements compared to the ILS-PAR and GBIE *** an urban canyon test with a low-cost receiver STA8100 produced by STMicroelectronics,the positioning accuracy of LBIE in three directions is 0.112 m,0.107 m,and 0.252 m,respectively,with improvements of 17.6%,27.2%,and 26.1%compared to GBIE,and 23.3%,28.2%,and 30.6%compared to ***,its computational time increases by 30–40%compared to ILS-PAR and is approximately half of that using TBIE.

关键词： Ambiguity resolution Best integer equivariant estimation Laplacian distribution Urban environments Low-cost GNSS receivers Real-time kinematic

Asymmetrically coordinated single atom Cu catalyst with unsaturated C-Cu-N structure for CO_(2) reduction to CO

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Nano Research 2024年第5期17卷 3911-3918页

作者： zheng liu Yuxuan liu Jingqiao Zhang Ting Cao Zhiyi Sun Juzhe liu Huishan Shang State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China SEPA Key Laboratory of Eco-Industry Chinese Research Academy of Environmental SciencesBeijing 100012China The Key Laboratory of Resources and Environmental System Optimization Ministry of EducationCollege of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China School of Chemical Engineering Zhengzhou UniversityZhengzhou 450001China

Single atom catalysts(SACs)play a crucial role in energy catalysis due to their distinct coordination environment and high atomic utilization *** study focuses on the synthesis of a monatomic Cu catalyst with Cu-N1C1 coordination anchored to N-doped Ti_(3)C_(2)T_(x) MXene(Cu SA@N-Ti_(3)C_(2)T_(x))to achieve efficient reduction of CO_(2) to *** characterization,including morphology and multispectral analysis,confirmed the uniform distribution of asymmetrically coordinated Cu atoms in unsaturated C-Cu-N bridge fragments on Ti_(3)C_(2)T_(x).The Cu SA@N-Ti_(3)C_(2)T_(x) catalyst exhibited an excellent CO selectivity with Faraday efficiency of 97.4%at-0.58 V *** hydrogen electrode(RHE)and satisfactory *** in situ X-ray absorption fine structure(XAFS)results confirmed that the carbon dioxide reduction reaction(CO_(2)RR)product distribution is mainly affected by potential-dependent valence change of Cu *** findings highlight the extensive potential of tuning coordination structure of MXene-based single-atom catalysts for CO_(2) reduction reactions.

关键词： cooper single atom atomic regulation MXene Ti_(3)C_(2)T_(x) CO_(2)reduction

Preparation and Swelling Kinetic Analysis of Poly (HPMC-co-AA-co-AM) Super Absorbent Resin

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 790-799页

作者：马砺 WANG Xin liu Xixi WEI Gaoming GUO ying School of Safety Science and Engineering Xi’an University of Science and TechnologyXi'an 710054China Key Laboratory of Coal Fire Disaster Prevention Xi’an University of Science and TechnologyXi'an 710054China School of Energy Engineering Xi’an Uni-versity of Science and TechnologyXi'an 710054China Yanzhou Coal Mining Co. Ltd.Zoucheng 237500China

Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking ***,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction *** optimized conditions are obtained by the experiment repeating for several *** water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,***,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are *** is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.

关键词： super absorbent resin swelling kinetics water absorption graft copolymerization hydroxypropyl methyl cellulose

***2 regulates plant height by affecting the main inflorescence length and first effective branch height in Brassica napus L.

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The Crop Journal 2024年第4期12卷 1102-1111页

作者： Chengke Pang Jun Yu Liang Zhang Min Tang Hongfang liu ying Cai Feng Chen Jiefu Zhang Wei Hua Xiaodong Wang Ming zheng Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences Key Laboratory of Biology and Genetic Improvement of Oil CropsMinistry of Agriculture and Rural AffairsWuhan 430062HubeiChina Key Laboratory of Cotton and Rapeseed Ministry of Agriculture and Rural AffairsKey Laboratory of Jiangsu Province for AgrobiologyInstitute of Industrial CropsJiangsu Academy of Agricultural SciencesNanjing 210014JiangsuChina National Key Laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070HubeiChina

Rapeseed(Brassica napus L.)is one of the main oil crops in the world,and increasing its yield is of great significance for ensuring the safety of edible ***,improving rapeseed plant architecture is an effective way to increase rapeseed yield with higher planting ***,the regulatory mechanism of rapeseed plant architecture is poorly *** this study,a dwarf rapeseed mutant dwarf08(df08)is obtained by ethyl methane sulfonate(EMS)-*** decrease in plant height of df08 is mainly caused by the reduction in main inflorescence length and first effective branch height and controlled by a single semi-dominant *** hybrid plants(F1)show a semi-dwarf *** map-based cloning and transgenic assay,we confirm that the nonsynonymous single nucleotide variant(SNV)(C to T)in ***2,which is homologous with Arabidopsis(Arabidopsis thaliana)BIN2,is responsible for the dwarfism of ***2 interacts with BnaBZR1/BES1 and involves in brassinosteroids(BRs)signal *** to Leucine substitution in 284(P284L)enhances the protein stability of ***2-D,disrupts BRs signal transduction and affects the expression of genes regulating cell division,leading to dwarfism of *** study provides a new insight for the mechanism of rapeseed plant height regulation and creates an elite germplasm that can be used for genetic improvement of rapeseed architecture.

关键词： Brassica napus Plant height Brassinosteroids BIN2

Microstructure and Mechanical Behavior of Mg-Based Bimetal Plates with High Formability Sleeve by Co-extrusion

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 499-512页

作者： Yue-Hui Dang Sheng-Lin liu Xiao-Lei Ai Xiao-Wei Feng Bo Feng Zhuo Tian ying-Fei Lin Huan-Tao Chen Kai-Hong zheng School of Materials Science and Engineering Chang’an UniversityShaanxi 710064China Guangdong Key Laboratory of Metal Toughening Technology and Application Institute of New MaterialsGuangdong Academy of SciencesGuangzhou 510650China

In this study,microstructure and mechanical behavior of two types of Mg-based bimetal plates with a high formability sleeve were systematically studied,with a great emphasis on the effect of the interface characteristic and the sleeve fraction on the plasticity of composite *** rule of mixtures(ROM)for elongation was also *** results show that when there is no or thin diffusion layer with thickness of about 3μm,Mg-based bimetal plates have a good plasticity with elongation of about 19-24%,and the ROM predicted elongations are very close to the experimental *** contrast,with a diffusion layer about 95-155μm thick,Mg-based bimetal plates exhibit a poor plasticity with elongation of about 11-17%,and the experimental elongations largely deviate from the ROM *** plasticity of Mg-based bimetal plates increases with increasing sleeve *** study provides new insights on the plastic deformation of Mg-based bimetal composites with a high formability sleeve.

关键词： Mg-based composites Co-extrusion Microstructure Mechanical behavior Plastic deformation

Phase Transitions and Seepage Characteristics during the Depletion Development of Deep Condensate Gas Reservoirs

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Energy Engineering 2024年第10期121卷 2797-2823页

作者： Qiang liu Rujun Wang Yintao Zhang Chong Sun Meichun Yang Yuliang Su Wendong Wang ying Shi zheng Chen Exploration and Development Technology Research and Development Center of Ultra-Deep Complex Oil and Gas Reservoirs Petro China Tarim Oilfield CompanyKorla841000China School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580China

Deep condensate gas reservoirs exhibit highly complex and variable phase behaviors,making it crucial to understand the relationship between fluid phase states and flow *** study conducts a comprehensive analysis of the actual production process of the deep condensate gas well A1 in a certain oilfield in *** phase behavior analysis and CMG software simulations,the study systematically investigates phase transitions,viscosity,and density changes in the gas and liquid phases under different pressure conditions,with a reservoir temperature of 165°*** research covers three crucial depletion stages of the reservoir:single-phase flow,two-phase transition,and two-phase *** findings indicate that retrograde condensation occurs when the pressure falls below the dew point pressure,reachingmaximum condensate liquid production at around *** pressure decreases,gas phase density and viscosity gradually decrease,while liquid phase density and viscosity show an increasing *** the initial single-phase flow stage,maintaining a consistent gas-oil ratio is observed when both bottom-hole and reservoir pressures are higher than the dew point ***,a sudden drop in bottom-hole pressure below the dew point triggers the production of condensate oil,significantly reducing subsequent gas and oil *** the transitional two-phase flow stage,as the bottom-hole pressure further decreases,the reservoir exhibits a complex flow regime with coexisting areas of gas and *** the subsequent two-phase flow stage,when both bottom-hole and reservoir pressures are below the dew point pressure,a significant increase in the gas-oil ratio is *** reservoir manifests a two-phase flow regime,devoid of single-phase gas flow *** lowpressure conditions in deep condensate gas reservoirs,considerations include gas injection,gas lift,and cyclic gas injection and production in surrounding ***,techniques such as hot nitrogen or CO

关键词： Deep condensate gas reservoirs depletion development phase behavior percolation laws dynamic production analysis