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An Initial Residual Stress Inference Method by Incorporating Monitoring Data and Mechanism Model

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 47-65页

作者： Shuguo Wang Yingguang Li Changqing Liu zhiwei zhao Nanjing University of Aeronautics and Astronautics Nanjing 210016China

Initial residual stress is the main reason causing machining deformation of the workpiece,which has been deemed as one of the most important aspects of machining quality *** inference of the distribution of initial residual stress inside the blank has significant meaning for machining deformation *** to the principle error of existing residual stress detection methods,there are still challenges in practical *** at the detection problem of the initial residual stress field,an initial residual stress inference method by incorporating monitoring data and mechanism model is proposed in this *** data during machining process is used to represent the macroscopic characterization of the unbalanced residual stress,and the finite element numerical model is used as the mechanism model so as to solve the problem that the analytic mechanism model is difficult to establish;the policy gradient approach is introduced to solve the gradient descent problem of the combination of learning model and mechanism ***,the initial residual stress field is obtained through iterative calculation based on the fusing method of monitoring data and mechanism *** results show that the proposed inference method of initial residual stress field can accurately and effectively reflect the machining deformation in the actual machining process.

关键词： Initial residual stress Inference Monitoring data Mechanism model Policy gradient

Robust Optimization of Municipal Solid Waste Collection and Transportation with Uncertain Waste Output: A Case Study

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Journal of Systems Science and Systems Engineering 2022年第2期31卷 204-225页

作者： Sicheng Zhang Jianwen Zhang zhiwei zhao Chunlin Xin School of Economics and Management Beijing University of Chemical TechnologyBeijing 100029China School of Mechanical Engineering Beijing University of Chemical TechnologyBeijing 100029China

Garbage collection is an important issue in urban environmental *** the increased awareness of urban residents regarding safety,environmental protection,and health in recent years,it is necessary to logically organize municipal solid waste collection and transportation routes while also considering economic and social *** article focuses on the optimization of the waste transportation routes of garbage *** the objective of minimizing transportation costs and maximizing resident satisfaction,we establish a robust optimization model for the multi-trip collection and transportation of municipal solid waste in an uncertain *** satisfaction is defined as the penalty cost against a time window *** Bertsimas robust optimization method is applied to characterize the uncertainty,and the decision-making scheme of the receiving route is used to adapt to waste volume *** conduct a case study based on real-world data for municipal solid waste collection and transportation in the Dongcheng District of Beijing,*** solution is validated using the CPLEX program,and the validity of the model is *** addition,a sensitivity analysis of related parameters is conducted to study the impacts of variations in work hour limits and time windows on the total cost and service levels,as well as their relationships with the level of *** could help decision-makers make reasonable choices based on actual conditions and to balance reductions in total cost with service level improvements.

关键词： Robustness and sensitivity analysis municipal solid waste vehicle routing problem garbage collection and transportation under uncertainty resident satisfaction

On the Synthesis of Stereocalpin A： Partial Retraction/ Correction of Previous Results and Rationalization of the Hidden Difficulties

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Chinese Journal of Chemistry 2017年第7期35卷 1185-1194页

作者： zhiwei zhao Yikang Wu Yan Li Hubei Collaborative Innovation Center for Advaneed Organic Chemical Materials and Ministry-of-Education Key Laboratory for Synthesis and Application of Organic Functional Molecules Hubei University Wuhan Hubei 430062 China State Key Laboratory of Bioorganic and Natural Products' Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

In continuation/checking of a previous synthesis directed toward the literature structure of stereocalpin A it was found that the data for a substantial part of the intermediates reported before were incorrect. Some of the transfor- mations were not successfully reproduced and the failures were shown to be consequences of the presence of the N-Me and the particular location of the ester linkage. The origins of the ＂extra/minor＂ signals in the NMR for most of the intermediates, which tend to be mistaken as signs for the presence of impurity/isomers, are also discussed.

关键词： peptide natural product aldol reaction cyclization condensation

Adsorption mechanisms of PFOA onto activated carbon anchored with quaternary ammonium/epoxide-forming compounds: A combination of experiment and model studies

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Journal of Environmental Sciences 2020年第12期32卷 94-102页

作者： Chen Yuan Yang Huang Fred SCannon zhiwei zhao Shenzhen Academy of Environmental Science Shenzhen 518001China College of Urban Construction and Environmental Engineering Chongqing UniversityChongqing 400045China Department of Civil and Environmental Engineering Pennsylvania State UniversityUniversity ParkPA 16802USA College of Resources and Environment Chengdu University of Information TechnologyChengdu 610225China

When wood-based activated carbon was tailored with quaternary ammonium/epoxide(QAE) forming compounds(QAE-AC), this tailoring dramatically improved the carbon's effectiveness for removing perfluorooctanoic acid(PFOA) from groundwater. With favorable tailoring, QAE-AC removed PFOA from groundwater for 118,000 bed volumes before halfbreakthrough in rapid small scale column tests, while the influent PFOA concentration was 200 ng/L. The tailoring involved pre-dosing QAE at an array of proportions onto this carbon, and then monitoring bed life for PFOA removal. When pre-dosing with 1 mL QAE, this PFOA bed life reached an interim peak, whereas bed life was less following 3 mL QAE pre-dosing, then PFOA bed life exhibited a steady rise for yet subsequently higher QAE pre-dosing levels. Large-scale atomistic modelling was used herein to provide new insight into the mechanism of PFOA removal by QAE-AC. Based on experimental results and modelling, the authors perceived that the QAE's epoxide functionalities cross-linked with phenolics that were present along the activated carbon's graphene edge sites, in a manner that created mesopores within macroporous regions or created micropores within mesopores regions. Also, the QAE could react with hydroxyls outside of these pore, including the hydroxyls of both graphene edge sites and other QAE molecules. This latter reaction formed new pore-like structures that were external to the activated carbon grains. Adsorption of PFOA could occur via either charge balance between negatively charged PFOA with positively charged QAE, or by van der Waals forces between PFOA's fluoro-carbon tail and the graphene or QAE carbon surfaces.

关键词： Perfluorooctanoic acid Nitrate Carbon Atomistic model Adsorption mechanism

Influence of Axial Loads to Propagation Characteristics of the Elastic Wave in a Non-Uniform Shaft

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Chinese Journal of Mechanical Engineering 2019年第4期32卷 140-152页

作者： Yimin Wei zhiwei zhao Wenhua Chen Qi Liu National and Local Joint Engineering Research Center of Reliability Analysis and Testing for Mechanical and Electrical Products Zhejiang SciTech University

The vibration propagates through the shaft in the form of elastic waves. The propagation characteristics of the elastic waves are a ected by the axial loads. The influence of the axial loads to the propagation characteristics of the elastic waves is studied in this paper. Firstly, the transfer matrix of the elastic waves for the non-uniform shaft with axial loads is deduced by combining the transfer matrix without axial load and the additional equation caused by the axial load. And then, a numerical method is used to study the influence of the axial load, non-uniformity and the rotating speed to the propagation characteristics of the elastic waves. It’s found that a new Stop Band will appear due to the axial force, and the central frequency of which will decrease as the increase of the force, while the band width of which remains the same. The central frequency of the new Stop Band will also increase as the increase of the cross-section area ratio;however, the rotating speed of the shaft doesn’t a ect the propagation characteristics of the elastic waves obviously. Finally, an experimental rig is built up for further study, even though there are some small local errors, the results of experiments match well with the numerical ones, which indicates the validation of the theoretical results. The result can help to study the influence of the axial load to the dynamics of a non-uniform shaft and help to reveal the vibration propagating mechanism in such a shaft.

关键词： Axial force Propagation characteristic Non-uniform shaft Elastic wave Transfer matrix

Surface geometry and magnetism of Eu@C_(60) monolayer on Ag(111)

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Science China(Physics,Mechanics & Astronomy) 2012年第9期55卷 1589-1593页

作者： zhao zhiwei WANG Jing LIU Ying Department of Physics Hebei Normal Universityand Hebei Advanced Thin Film LaboratoryShijiazhuang 050016China National Key Laboratory for Materials Simulation and Design Beijing 100083China

The surface geometry, electronic structure, and magnetism of Eu@C60 monolayer absorbed on Ag(111) have been investigated within the framework of density functional theory. The Eu@C60 monolayer has been constructed on Ag(111) substrate by one of the hexagon faces of C60 downward and its mirror plane face parallel to Ag(111). The Eu@C60 monolayer induces a recon- struction of the Ag(111) substrate and the perpendicular distance between the Eu@C60 and Ag(111) surface is 2.06 A, being shorter than that between C60 and Ag(lll) surface by 0.05A. There is no chemical bond formed between the Eu@C60 and Ag(111), and only 0.55e transferred from Ag(111) to Eu@C60. A large magnetic moment about 6.80/μB per unit cell is found for Eu@C60/Ag(111) system.

关键词： endohedral fullerene two-dimensional C60 domain magnetic organic molecule

Reaction performance of fluidized bed catalytic reactor of Group C^(+)particles

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Particuology 2021年第1期19卷 5-16页

作者： zhiwei zhao Yandaizi Zhou Xiaojun Bao Jesse Zhu Haiyan Liu State Key Laboratory of Heavy Oil Processing Department of Chemical EngineeringChina University of PetroleumBeijing 102249China Particle Technology Research Center Department of Chemical and Biochemical EngineeringThe University of Western OntarioLondonOntario N6A 5B9Canada

Group C particles are often regarded as non-fluidizable but have proven to effectively fluidize with nanoparticle addition,which results in small bubbles and a high gas holdup in the dense phase during the *** C^(+)particles provide an increased surface area for gas-solid contact and improve the reaction performance,especially for gas-phase catalytic *** the basis of a previous study of the ozone decomposition reaction using Group C^(+)particles,a two-phase model was used to evaluate the reactor contact efficiency,and was used to compare the partial oxidation performance of the n-butane to maleic anhydride reaction in fluidized-bed catalytic reactors of Group C^(+)and Group A *** reactor with Group C^(+)particles achieved a higher n-butane conversion and MAN yield compared with that using Group A particles,based on the identical catalyst quantity or on the same gas residence ***,the reactor with Group C^(+)particles can achieve the same reaction conversion and yield with fewer catalysts or a smaller reactor size,or ***,the fluidized bed catalytic reactor of Group C^(+)particles is expected to be of major significance in industrial processes,especially for gas-phase catalytic reactions.

关键词： Group C^(+)particles Fluidized bed catalytic reactor Reactor performance Nanoparticles Modified two-phase model Effective surface area

In-situ fabrication of Bi_(2)S_(3)/BiVO_(4)/Mn_(0.5)Cd_(0.5)S-DETA ternary S-scheme heterostructure with effective interface charge separation and CO_(2) reduction performance

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Journal of Materials Science & Technology 2022年第22期117卷 109-119页

作者： zhiwei zhao Xiaofeng Li Kai Dai Jinfeng Zhang Graham Dawson Laboratory of Green and Precise Synthetic Chemistry and Applications Ministry of EducationAnhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental RemediationHuaibei Normal UniversityHuaibei 235000China Department of Chemistry Xi’an Jiaotong Liverpool UniversitySuzhou 215123China

Exploring new and efficient photocatalysts to boost photocatalytic CO_(2) reduction is of critical importance for solar-to-fuel *** this study,through the in-situ growth method,a series of S-scheme mechanism Bi_(2)S_(3)/BiVO_(4)/Mn_(0.5)Cd_(0.5)S-DETA nanocomposites with good photocatalytic activity were *** extremely small size of Mn_(0.5)Cd_(0.5)S-DETA nanoparticles provides more active sites for photocatalytic *** order to solve the serious shortcomings of sulfide photo-corrosion,BiVO_(4) were introduced as oxidation catalyst to consume too many holes and improve the stability of the *** addition,the in-situ growth method produces the reduction cocatalyst Bi_(2)S_(3) during the BiVO_(4) and Mn_(0.5)Cd_(0.5)S-DETA recombination process,thereby improving the efficiency of charge transfer at their interface *** ternary composite unveils a higher CO_(2)-reduction rate(44.74μmol g^(−1) h^(−1))comparing with pristine BiVO_(4)(14.11μmol g^(−1) h^(−1)).The enhanced photocatalytic CO_(2) reduction performance is due to the special interface structure of the S-scheme Bi_(2)S_(3)/BiVO_(4)/Mn_(0.5)Cd_(0.5)S-DETA photocatalyst,which facilitates the charge separation at the interface and improves its photocatalytic activity and stability.

关键词： Step-scheme heterojunction Bi_(2)S_(3) BiVO_(4) Mn_(0.5)Cd_(0.5)S Photocatalytic CO_(2)reduction

A New Dynamics Analysis Model for Five-Axis Machining of Curved Surface Based on Dimension Reduction and Mapping

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Chinese Journal of Mechanical Engineering 2023年第6期36卷 172-184页

作者： Minglong Guo zhaocheng Wei Minjie Wang zhiwei zhao Shengxian Liu Key Laboratory for Precision and Non-traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024People’s Republic of China Institute of Mechanical Manufacturing Technology China Academy of Engineering PhysicsMianyang 621000China

The equipment used in various fields contains an increasing number of parts with curved surfaces of increasing ***-axis computer numerical control(CNC)milling is the main parts machining method,while dynamics analysis has always been a research *** cutting conditions determined by the cutter axis,tool path,and workpiece geometry are complex and changeable,which has made dynamics research a major *** this reason,this paper introduces the innovative idea of applying dimension reduction and mapping to the five-axis machining of curved surfaces,and proposes an efficient dynamics analysis *** simplify the research object,the cutter position points along the tool path were discretized into inclined plane five-axis *** cutter dip angle and feed deflection angle were used to define the spatial position relationship in five-axis *** were then taken as the new base variables to construct an abstract two-dimensional space and establish the mapping relationship between the cutter position point and space point sets to further simplify the dimensions of the research *** on the in-cut cutting edge solved by the space limitation method,the dynamics of the inclined plane five-axis machining unit were studied,and the results were uniformly stored in the abstract space to produce a ***,the prediction of the milling force and vibration state along the tool path became a data extraction process that significantly improved *** experiments were also conducted which proved the accuracy and efficiency of the proposed dynamics analysis *** study has great potential for the online synchronization of intelligent machining of large surfaces.

关键词： Curved surface Five-axis machining Dimension reduction and mapping Milling force Dynamics