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Analysis and Optimization on Factors Affecting Forming Quality of Half Axle Gears Warm Precision Forging

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Chinese Journal of Mechanical Engineering 2010年第1期23卷 110-114页

作者： wang menghan CHEN Xihou ZHOU Jie College of Material Science and Engineering Chongqing University Chongqing 400044 China School of Electronic Information and Automation Chongqing University of Technology Chongqing 400050 China

Half axle gears is produced by precision forging popularly because of the advantages in minimum machining allowances, lower material consumption and good service properties. But the forming quality of precision forging is difficult to control. Many simulations and analysis of precision forging process were taken by previous researchers. But no concrete method is proposed to evaluate and optimize the forming quality of half axel gears. The primary purpose of this work is improving the forming quality of half axel gears by analyzing and optimizing the affected factors of forming quality. The enclosed-die warm forging process of half axle gears was developed, and a new type of die-set used on double action hydraulic press was brought forward. The main influential factors of precision forming quality were analyzed after the forming process had been simulated by using finite element method（FEM）. These factors include die structure, web thickness and web position. A method used to evaluate the forming quality was established, which investigated the maximal forming load, the metal filling rate and the material damage factor. The FEM simulations of half axle gears precision forging were evaluated by this method. The results show that the best forming quality can be achieved when the punches were added with bosses, the web located at the middle plant of the gear, and the web thickness was 30 percent of the inner hole diameter. Verification experiments taking the above optimized parameters were performed on a 7.8 MN double action hydraulic press. The trial products were formed well. And their geometric precision meets the demand. The verification result shows that the optimization of the influential factors, according to the simulations and the evaluation method, can improve the forming quality. The new structure of precision forging die-set and the new evaluation method guarantee a high forming quality ofhalfaxel gears.

关键词： warm precision forging half axle gears forming quality die structure web

Resource Allocation Based on DEA and Non-Cooperative Game

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Journal of Systems Science & Complexity 2021年第6期34卷 2231-2249页

作者： wang menghan LI Lin DAI Qianzhi SHI Fangnan Department of Statistics and Finance The School of ManagementUniversity of Science and Technology of ChinaHefei 230026China Academy of Mathematics and Systems Science Chinese Academy of ScienceBeijing 100190China School of Economics Hefei University of TechnologyHefei 230009China Center for Industrial Information and Economic Research Hefei University of TechnologyHefei 23QQQ9China

Resource allocation is one of the most important applications of data envelopment analysis(DEA).Usually,the resource to be allocated is directly related to the interests of decision-making units(DMUs),thus the dynamic non-cooperative game is one of the representative behaviours in the allocation ***,it is rarely considered in the previous DEA-based allocation studies,which may reduce the acceptability of the allocation ***,this paper proposes a DEA-based resource allocation method considering the dynamic non-cooperative game behaviours of *** authors first deduce the efficient allocation set under the framework of variable return to scale(VRS)and build the allocation model subjecting to the allocation *** an iteration algorithm based on the concept of the non-cooperative game is provided for generating the optimal allocation *** interesting characteristics of the algorithm are proved,including i)the algorithm is convergent,ii)the optimal allocation plan is a unique Nash equilibrium point,and iii)the optimal allocation plan is unique no matter which positive value the initial allocation *** advantages of the allocation plan have been *** example,the allocation plan is more balanced,has more incentives and less outliers,compared with other DEA-based allocation ***,the proposed method is applied to allocate the green credit among the 30 Chinese iron and steel enterprises,and the results highlight the applicability of the allocation method and solution ***,the approach can provide decision makers with a useful resource allocation tool from the perspective of dynamic non-cooperative game.

关键词： Data envelopment analysis(DEA) game theory green credit Nash equilibrium resource allocation

Quantitative analysis of work hardening and dynamic softening behaviors of Cu-6 wt pct Ag binary alloy based on true stress vs strain curves

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Acta Metallurgica Sinica(English Letters) 2012年第6期25卷 420-434页

作者： menghan wang Wenhao wang Jingjing DONG Linhui ZHANG Yunping LI Akihiko CHIBA School of Material Science and Engineering Chongqing University Chongqing 400044 China Institute for Materials Research Tohoku University Sendai 980-8577 Japan

The work hardening and dynamic softening behaviors of Cu-6 wt pct Ag binary alloy were studied by hot compression tests under temperature range of 700-850℃ at strain rates of *** critical conditions for the onset of dynamic recrystallization （DRX） were determined based on the conventional strain hardening rate curves （dσ/dε versus σ）.The progress of DRX was analyzed by constructing a model of volume fraction of DRX based on flow *** strain rate sensitivity （SRS） and activation volume V were *** results show that the DRX almost can happen under all deformation conditions even at high Z deformations where dynamic recovery （DRV） is the main softening *** DRX fraction curves can well predict the DRX *** strain has significant effects on SRS at the strain rates of 0.01s-1 and 10s-1 which are mainly due to off-equilibrium saturation of dislocation storage and annihilation while the effects of the temperature on the SRS are based on the uniformity of microstructure *** formation of ＂forest＂ of dislocation is contributed to the low activation volume V＊（about 168b3） which is independent of Z values at the initial *** cross-slip due to dislocation piled up beyond the grain boundaries or obstacles is related to the low activation volume under the high Z deformation conditions at high strain （ε=0.6） while the fine DRX grains coarsed is the main reason for the high activation volume at low Z under the same strain conditions.

关键词： Cu-Ag alloy Work hardening Dynamic recrystallization Strainrate sensitivity Activation volume

Heritage tourism evolution in Guangfu Ancient City,Hebei Province,China:an analysis with the improved creative destruction model

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Built Heritage 2022年第3期6卷 28-42页

作者： menghan wang Xiaoran Bai Mingming Su School of Environment&Natural Resources Renmin University of ChinaBejing 100872China

Ancient cities and towns are popular tourism destinations *** this paper,Guangfu Ancient City in Yongnian County,Hebei Province,China,is taken as the case study and the modifed creative destruction model is applied as the analytical framework to evaluate the multiactor dynamics of heritage tourism development.A mixed method approach is adopted,including a local resident survey,in-depth interviews with staf of the Guangfu Ancient City tourism site and government ofcials responsible for the heritage conservation and tourism development of the site,and a review of online tourist reviews,relevant government documents and *** on the modifed creative destruction model,local residents’attitudes towards tourism development,changes in tourist numbers,the level of business and government investments,and the motivations of diferent stakeholders in tourism development are assessed by synthesising on-site research,historical data and other ***,the tourism development stages for Guangfu Ancient City are identifed as the precommodifcation stage before 2006,the early commodifcation stage from 2006 to 2011 and the advanced commodifcation stage from 2012 to *** fndings indicate that with rapid increases in investments from both corporate and government sources and in the number of tourists,the attitude of local residents towards tourism development remained *** results show that instead of entering the initial destruction stage,Guangfu Ancient City is in the transition stage from advanced commodifcation to creative enhancement given the government’s dominant role in tourism development,the heritage conservation motives of tourism entrepreneurs,the benefts to residents from tourism development ensured by government policies,and the shift in tourist type to postmodern tourists with double *** applicability of the modifed creative destruction model is further discussed,and policy and management recommendations are generated to support

关键词： Creative destruction Creative enhancement Heritage tourism Tourism commercialisation Stakeholder Guangfu Ancient City

Role of Stokes Drift in Ocean Dynamics Under Typhoon Conditions in the Bohai Sea

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Journal of Ocean University of China 2024年第1期23卷 33-45页

作者： LI Haoqian WAN Kai wang menghan DENG Zeng’an CAO Yu North China Sea Marine Forecasting Center Qingdao 266061China Shandong Provincial Key Laboratory of Marine Ecology and Environment&Disaster Prevention and Mitigation Qingdao 266061China North China Sea Offshore Engineering Survey Institute Qingdao 266061China School of Marine Science and Technology Tianjin UniversityTianjin 300072China South China Sea Marine Forecasting Center Guangzhou 510006China

The effect of Stokes drift production(SDP),which includes Coriolis-Stokes forcing,Langmuir circulation,and Craik-Lei-bovich vortexes,on the upper ocean during typhoon passage in the Bohai Sea(BS),China,is investigated by using a coupled wave-current *** role of SDP in turbulent mixing and the further dynamics during the entire typhoon period are comprehensively *** results show that SDP greatly increases turbulent mixing at all depths under typhoon conditions by up to seven times that under normal weather *** generally strengthens sea surface cooling by more than 0.4℃,with the maximum reduction in sea surface temperature(SST)at the during-typhoon stage exceeding 2℃,which is approximately seven times larger than that under normal weather *** SDP-induced decrease in current speed can exceed 0.2ms^(-1),and the change in current direction is generally opposite the wind *** results suggest that Stokes drift depresses the effect of strong winds on currents by intensifying turbulent *** layer depth(MLD)is distinctly increased by O(1)during typhoons due to SDP and can deepen by more than *** addition,the continuous effects of SDP on SST,current,and MLD at the after-typhoon stage indi-cate a hysteretic response between SDP and typhoon actions.

关键词： Stokes drift production Langmuir turbulence rurbulent mixing typhoon coupled model

Evaluating the Applicability and Health Benefits of the Graded Heat Health Risk Early Warning Model-Jinan City,Shandong Province,China,2022

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China CDC weekly 2023年第29期5卷 642-646,I0001-I0003页

作者： Chen Chen Jing Liu menghan wang Liangliang Cui Tiantian Li China CDC Key Laboratory of Environment and Population Health National Institute of Environmental HealthChinese Center for Disease Control and PreventionBeijingChina Key Laboratory of Public Health Safety of Hebei Province College of Public HealthHebei UniversityBaoding CityHebei ProvinceChina Department of Environmental Health Jinan Center for Disease Control and PreventionJinan CityShandong ProvinceChina

What is already known about this topic?The heat health early warning model serves as an effective strategy for reducing health risks related to heatwaves and improving population *** high-income countries have taken the lead in conducting research and implementing measures aimed at safeguarding their *** is added by this report?The graded heat health risk early warning model(GHREWM)in Jinan City has demonstrated efficacy in safeguarding males,females,individuals aged above 75 years,and those with cardiopulmonary *** the summer of 2022,the warning stage of GHREWM contributed to the prevention of 10.9 deaths per million individuals,concurrently averting health-related economic losses estimated at approximately 227 million Chinese Yuan(CNY).What are the implications for public health practice?The GHREWM has the potential to enhance cities’adaptability to climate *** is crucial to incorporate additional adverse health endpoint data in the development of early warning models,as this will improve their applicability and protective efficacy.

关键词： income conducting measures

The evolution of sex chromosome dosage compensation in animals

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Journal of Genetics and Genomics 2020年第11期47卷 681-693页

作者： Jiabi Chen menghan wang Xionglei He Jian-Rong Yang Xiaoshu Chen Department of Biology and Medical Genetics Zhongshan School of MedicineSun Yat-sen UniversityGuangzhouChina State Key Laboratory of Biocontrol College of Life SciencesSun Yat-sen UniversityGuangzhouChina Department of Biomedical Informatics Zhongshan School of MedicineSun Yat-sen UniversityGuangzhouChina RNA Biomedical Institute Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhouChina Program in Cancer Research Zhongshan School of MedicineThe Fifth Affiliated HospitalSun Yat-sen UniversityGuangzhouChina

The evolution of heteromorphic sex chromosomes shall lead to gene expression dosage problems,as in at least one of the sexes,the sex-linked gene dose has been reduced by *** has been proposed that the transcriptional output of the whole X or Z chromosome should be doubled for complete dosage compensation in heterogametic ***,owing to the variability of the existing methods to determine the transcriptional differences between sex chromosomes and autosomes(S:A ratios)in different studies,we collected more than 500 public RNA-Seq data set from multiple tissues and species in major clades and proposed a unified computational framework for unbiased and comparable measurement of the S:A ratios of multiple *** also tested the evolution of dosage compensation more directly by assessing changes in the expression levels of the current sex-linked genes relative to those of the ancestral sex-linked *** found that in mammals and birds,the S:A ratio is approximately 0.5,whereas in insects,fishes,and flatworms,the S:A ratio is approximately *** analysis showed that the fraction of dosage-sensitive housekeeping genes on the X/Z chromosome is significantly correlated with the S:A *** addition,the degree of degeneration of the Y chromosome may be responsible for the change in the S:A ratio in mammals without a dosage compensation *** observations offer unequivocal support for the sex chromosome insensitivity hypothesis in animals and suggest that dosage sensitivity states of sex chromosomes are a major factor underlying different evolutionary strategies of dosage compensation.

关键词： Dosage compensation Sex chromosome Genomic evolution

Revealing the role of CCoAOMT1: fine-tuning bHLH transcription factors for optimal anther development

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Science China(Life Sciences) 2024年第3期67卷 565-578页

作者： Zesen Lai Jianzheng wang Ying Fu menghan wang Hong Ma Shiqing Peng Fang Chang State Key Laboratory of Genetic Engineering Ministry of Education Key Laboratory of Biodiversity Sciences and Ecological Engineering and Institute of Biodiversity SciencesInstitute of Plant BiologySchool of Life SciencesFudan UniversityShanghai 200438China School of Tropical Agriculture and Forestry Agriculture-Rural Affairs and Rural RevitalizationHainan UniversityHaikou 570228China Key Laboratory of Biology and Genetic Resources of Tropical Crops Ministry of AgricultureInstitute of Tropical Bioscience and BiotechnologyChinese Academy of Tropical Agricultural SciencesHaikou 571101China Department of Biology Huck Institutes of the Life SciencesPennsylvania State UniversityUniversity ParkPA 16802USA

The tapetum,a crucial innermost layer encompassing male reproductive cells within the anther wall,plays a pivotal role in normal pollen *** transcription factors (TFs) bHLH010/089/091 redundantly facilitate the rapid nuclear accumulation of DYSFUNCTIONAL TAPETUM 1,a gatekeeper TF in the ***,the regulatory mechanisms governing the activity of bHLH010/089/091 remain *** this study,we reveal that caffeoyl coenzyme A O-methyltransferase 1 (CCoAOMT1) is a negative regulator affecting the nuclear localization and function of bHLH010 and bHLH089,probably through their K259 *** findings underscore that CCoAOMT1 promotes the nuclear export and degradation of bHLH010 and ***,elevated CCoAOMT1 expression resulted in defective pollen development,mirroring the phenotype observed in bhlh010 bhlh089 ***,our investigation revealed that the K259A mutation in the bHLH089 protein disrupted its translocation from the nucleus to the cytosol and impeded its degradation induced by ***,transgenic plants with the probHLH089::bHLH089^(K259A)construct failed to rescue proper pollen development or gene expression in bhlh010 bhlh089 ***,these findings emphasize the need to maintain balanced TF homeostasis for male *** firmly establish CCoAOMT1 as a pivotal regulator that is instrumental in achieving equilibrium between the induction of the tapetum transcriptional network and ensuring appropriate anther development.

关键词： anther development nuclear localization bHLH O-methyltransferase transcription factor homeostasis

Optimization of Clinching Tools by Integrated Finite Element Model and Genetic Algorithm Approach

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Journal of Shanghai Jiaotong university(Science) 2019年第2期24卷 262-272页

作者： wang menghan XIAO Guiqian wang Jinqiang LI Zhi College of Materials Science and Engineering Chongqing University

Clinching is a convenient and efficient cold forming process that can join two sheets without any additional part. This study establishes an intelligent system for optimizing the clinched joint. Firstly, a mathematical model which introduces the ductile damage constraint to prevent cracking during clinching process is ***, an optimization methodology and its corresponding computer program are developed by integrated finite element model(FEM) and genetic algorithm(GA) approach. Secondly, Al6061-T4 alloy sheets with a thickness of 1.4 mm are used to verify this optimization system. The optimization program automatically acquires the largest axial strength which is approximately equal to 872 N. Finally, sensitivity analysis is implemented, in which the influence of geometrical parameters of clinching tools on final joint strength is analyzed. The sensitivity analysis indicates the main parameters to influence joint strength, which is essential from an industrial point of view.

关键词： mechanical clinching optimization design genetic algorithm(GA) ductile damage