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Science China(Technological Sciences) 2021年第5期64卷 957-970页

作者： XU xiaohu YE SongTao YANG ZeYuan YAN SiJie zhu DaHu DING Han State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Collaborative Innovation Center for Automotive Components Technology Wuhan University of TechnologyWuhan 430070China

Precision prediction of machined surface roughness is challenging facing the robotic belt grinding of complex blade,since this process is accompanied by significant elastic *** resulting poor prediction accuracy,to a great extent,is attributed to the existing prediction model which less considers the *** this paper,an improved scallop height model is developed to predict and assess the machined surface roughness by taking into account the elastic deformation and the varying curvature of blade,then robotic belt grinding experiments are carried out to evaluate the proposed model from the perspective of surface *** factors that influence the scallop height are analyzed,and the suitable empirical equation of surface roughness is proposed to assess and predict the surface quality from the aspect of blade concave and convex surface by adopting the constant scallop height machining.

关键词： robotic belt grinding scallop height elastic deformation surface roughness prediction

Exploring metro vibrancy and its relationship with built environment:a cross-city comparison using multi-source urban data

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geo-Spatial Information Science 2022年第2期25卷 182-196页

作者： Wei Tu Tingting zhu Chen Zhong xiaohu Zhang Yang Xu Qingquan Li Guangdong Key Laboratory of Urban Informatics and Shenzhen Key Laboratory of Spatial Smart Sensing and ServiceSchool of Architecture and Urban PlanningShenzhen UniversityShenzhenChina Ministry of Natural Resources(MNR)Key Laboratory for geo-Environmental Monitoring of Great Bay Area Shenzhen UniversityShenzhenChina The Bartlett Centre for Advanced Spatial Analysis(CASA) University College London(UCL)LondonUK Department of Urban Planning and Design The University of Hong KongHong KongChina Department of Land Surveying and geo-Informatics The Hong Kong Polytechnic UniversityHong Kong SARChina

Recent urban transformations have led to critical reflections on the blighted urban infrastruc-tures and called for re-stimulating vital urban ***,the metro has been recognized as the backbone infrastructure for urban mobility and the associated economy *** date,limited research has been devoted to investigating the relationship between metro vitality and built environment in mega-cities *** paper presents a multisource urban data-driven approach to quantify the metro vibrancy and its association with the underlying built *** smart card data is processed to extract metro ridership,which denotes the vibrancy around the metro station in physical *** media check-ins are crawled to measure the vitality of metros in virtual *** physical and virtual vibrancy are integrated into a holistic metro vibrancy metric using an entropy-based weighting *** built environment characteristics,including land use,transportation and buildings are modeled as independent *** significant influences of built environ-mental factors on the metro vibrancy are unraveled using the ordinary least square regression and the spatial lag *** experiments conducted in Shenzhen,Singapore and London,this study comes up with a conclusion that spatial distributions of metro vibrancy metrics in three cities are spatially *** regression analysis suggests that in all the three cities,more affluent urban areas tend to have higher metro virbrancy,while the road density,land use and buildings tend to impact metro vibrancy in only one or two *** results demonstrate the relationship between the metro vibrancy and built environment is affected by complex urban *** findings help us to understand metro vibrancy thus make proper policy to re-stimulate the important metro infrastructure in the future.

关键词： Urban vibrancy spatial-autocorrelation spatial lag model smart card data social media

How does working from home affect developer productivity?——A case study of Baidu during the COVID-19 pandemic

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Science China(Information Sciences) 2022年第4期65卷 141-155页

作者： Lingfeng BAO Tao LI Xin XIA Kaiyu zhu Hui LI xiaohu YANG College of Computer Science and Technology Zhejiang University Baidu Inc. Faculty of Information Technology Monash University

Nowadays, working from home(WFH) has become a popular work arrangement due to its many potential benefits for both companies and employees(e.g., increasing job satisfaction and retention of employees). Many previous studies have investigated the impact of WFH on the productivity of ***, most of these studies usually use a qualitative analysis method such as surveys and interviews,and the studied participants do not work from home for a long continuing time. Due to the outbreak of coronavirus disease 2019(COVID-19), a large number of companies asked their employees to work from home, which provides us an opportunity to investigate whether WFH affects their productivity. In this study, to investigate the difference in developer productivity between WFH and working onsite, we conduct a quantitative analysis based on a dataset of developers’ daily activities from Baidu Inc., one of the largest IT companies in China. In total, we collected approximately four thousand records of 139 developers’ activities of 138 working days. Out of these records, 1103 records are submitted when developers work from home due to the COVID-19 pandemic. We find that WFH has both positive and negative impacts on developer productivity in terms of different metrics, e.g., the number of builds/commits/code reviews. We also notice that WFH has different impacts on projects with different characteristics including programming language,project type/age/size. For example, WFH has a negative impact on developer productivity for large ***, we find that productivity varies for different developers. Based on these findings, we get some feedback from developers of Baidu and understand some reasons why WFH has different impacts on developer productivity. We also conclude several implications for both companies and developers.

关键词： WFH Developer Productivity developer productivity

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Adaptive nonlinear Kalman filters based on credibility theory with noise correlation

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Chinese Journal of Aeronautics 2024年第6期37卷 232-243页

作者： Quanbo ge Zihao SONG Bingtao zhu Bingjun ZHANG School of Automation Nanjing University of Information Science and TechnologyNanjing 210044China Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology Nanjing 210044China School of Electrical and Automation Engineering East China Jiaotong UniversityNanchang 330013China School of Logistics Engineering Shanghai Maritime UniversityShanghai 201306China School of Electronic and Information Engineering Tongji UniversityShanghai 200092China

To solve the divergence problem and overcome the difficulty in guaranteeing filtering accuracy during estimation of the process noise covariance or the measurement noise covariance with traditional new information-based nonlinear filtering methods,we design a new method for estimating noise statistical characteristics of nonlinear systems based on the credibility Kalman Filter(KF)theory considering noise *** method first extends credibility to the Unscented Kalman Filter(UKF)and Extended Kalman Filter(EKF)based on the credibility ***,an optimization model for nonlinear credibility under noise related conditions is established considering noise correlation.A combination of filtering smoothing and credibility iteration formula is used to improve the real-time performance of the nonlinear adaptive credibility KF algorithm,further expanding its application scenarios,and the derivation process of the formula theory is ***,the performance of the nonlinear credibility filtering algorithm is simulated and analyzed from multiple perspectives,and a comparative analysis conducted on specific experimental *** simulation and experimental results show that the proposed credibility EKF and credibility UKF algorithms can estimate the noise covariance more accurately and effectively with lower average estimation time than traditional methods,indicating that the proposed algorithm has stable estimation performance and good real-time performance.

关键词： Kalman filter Extended Kalman Filter(EKF) Unscented Kalman Filter(UKF) Credibility Noise correlation

Terminal attitude selection method of missile attack aircraft

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Chinese Journal of Aeronautics 2024年第2期37卷 385-400页

作者： Peng HOU Yang PEI Yuxue ge Mengjie zhu School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Research Department Shanghai Electro-Mechanical Engineering InstituteShanghai 201108China

The appropriate terminal attitude of missile is important to improve the damage effectiveness of fragmentation warhead against aircraft *** this paper,three missile terminal attitude selection methods are proposed to solve the problem of terminal attitude selection in different situations according to their respective evaluation *** MVE-based method uses the damage probability of each detonation point around the aircraft at a given attitude of missile to calculate the Mean Volume of Effectiveness(MVE)at the corresponding attitude,and then uses the MVE for different attitudes to select the terminal strike *** detonation position-based method addresses the case where the missile detonation position can be assessed in *** the effects of missile guidance errors and fuze activation position errors,Monte Carlo simulations are used to calculate the damage probability of aircraft with different strike attitudes,from which the terminal strike attitude is *** BP-ANN model-based method uses the constructed Back Propagation Artificial Neural Network(BP-ANN)model instead of simulation to calculate the evaluation indexes in the corresponding cases of MVE-based method and Detonation position-based method,which can improve the efficiency of attitude *** are conducted for different scenarios to verify the feasibility and effectiveness of the proposed method.

关键词： Aircraft vulnerability Attitude selection BP-ANN Damage probability Damage effectiveness

Preface for special issue on new analytical techniques and methods in drug metabolism and pharmacokinetics

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Journal of Pharmaceutical Analysis 2020年第3期10卷 I0001-I0002页

作者： Guangbo ge Mingshe zhu Institute of Interdisciplinary Integrative Medicine Research.Shanghai University of Traditional Chinese Medicine ShanghaiChina MassDefect Technologies Princeton.NJ.USA.

Analytical technologies and approaches for drug metabolism and pharmacokinetics(DMPK)research in the pharmaceutical industry and academic research institutes have evolved rapidly over the past *** one hand,the discovery and development of small molecule drug candidates requires earlier and better understanding of their absorption,distribution,metabolism and excretion(ADME)in human as well as their interactions with metabolizing enzymes.

关键词： metabolism pharmacokinetics drug

Luminescence properties of composite material Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)/light conversion agent with multilayer structure

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Journal of Rare Earths 2022年第1期40卷 34-40页

作者： Liubin Zheng Yanan zhu Zengyuan Pang Mingqiao ge College of Textile Science and Engineering Jiangnan UniversityWuxi 214122China Key Laboratory of Eco-Textiles Ministry of EducationJiangnan UniversityWuxi 214122China

In order to improve the red luminescent properties,Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)was selected as a blue persistent luminescent donor phosphor,while light conversion agent was utilized to tune the persistent luminescent spectra from blue to *** red luminescent material Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)/light conversion agent(SMED/LCA)was fabricated with light conversion agent and Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+)at a certain mass ***_(2)(Al2 O_(3) or MgF2)were coated on the surface of SMED/LCA through heterogeneous deposition *** structural and optical characteristics of the resulting samples were launched in terms of X-ray diffraction and emission spectrum as well as afterglow *** results demonstrate that the emission spectrum exhibits two emission bands,and the peaks are located at around 470 and 615 ***_(2),Al_(2)O_(3) and MgF_(2) are coated on the surface of SMED/LCA like a protective shell to maintain its stability and luminescent properties,the afterglow initial brightness is still up to 0.37 cd/m^(2) and the afterglow color purity calculated from CIE color coordinates is basically unchanged.

关键词： Sr_(2)MgSi_(2)O_(7):Eu^(2+),Dy^(3+) Light conversion agent Stability Multilayer structure Composite material Rare earths

Advancing from unimechanism polymerization to multimechanism polymerization: binary polymerization

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Science China Chemistry 2022年第3期65卷 602-610页

作者： Ning Ren Mengqi ge Gangsheng Tong Xinyuan zhu School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China

Polymerizations with multiple mechanisms performed simultaneously are promising but very challenging. As the key limitation,the complicated mutual influence between different mechanisms can be hardly defined and measured. Herein we establish a universal framework for the assessment of mutual influence between different mechanisms using binary polymerization for demonstration. The kinetics and thermodynamics of polymerization with two mechanisms are compared with the corresponding homopolymerization and the difference is expressed by a hybrid function. The hybrid function is composed of a hybrid parameter that describes the extent of mutual influence and a function that describes necessary conditions for mutual influence to occur. The extent of mutual influence can be calculated using kinetic and thermodynamic data without details of reaction mechanisms, for the first time providing a straightforward method to assess the mutual influence between different polymerization *** envision that the method has potential in more complex systems with multiple mechanisms/monomers with mutual influence.

关键词： binary polymerization multimechanism polymerization hybrid function hybrid parameter hybrid polymerization

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Vibration signal-based chatter identification for milling of thin-walled structure

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Chinese Journal of Aeronautics 2022年第1期35卷 204-214页

作者： Wenping MOU Shaowei zhu Zhenxi JIANG ge SONG NC Machining Plant Chengdu Aircraft Industrial(Group)Co.LtdChengdu 610092China

In high speed milling aeronautical part,tool condition monitoring(TCM)is very important,because it is prone to get a chatter owing to the low stiffness of thin-walled *** the TCM is key technology for automated *** this paper,aiming to chatter monitoring in thin-walled structure milling,a variational mode decomposition–energy distribution(VMD-ED)method is proposed to improve the identification *** a moving average root mean square–mean value(MARMS-MV)identification method and a variational mode decomposition–energy entropy(VMD-EE)identification method are also *** accuracy and computing time of the three methods are *** vibration signals collected from the spindle and worktable are also *** conducted experimental study shows that,the proposed VMD-ED method offers an identification method for chatter monitoring with greater sensitivity,better stability and less computing time,and mounting the vibration sensor on worktable is better than spindle for a chatter monitoring system.

关键词： Chatter Milling Thin-walled structure Tool condition monitoring Vibration

Simulation of the fatigue-wear coupling mechanism of an aviation gear

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Friction 2021年第6期9卷 1616-1634页

作者： Boyu ZHANG Huaiju LIU Caichao zhu Yibo ge State Key Laboratory of Mechancial Transmissions Chongqing UniversityChongqing 400044China Shanghai Peentech Equipment Tech.Co.Ltd. Shanghai 201800China

The contact fatigue of aviation gears has become more prominent with greater demands for heavy-duty and high-power density ***,the coexistence of tooth contact fatigue damage and tooth profile wear leads to a complicated competitive mechanism between surface-initiated failure and subsurface-initiated contact fatigue *** address this issue,a fatigue-wear coupling model of an aviation gear pair was developed based on the elastic-plastic finite element *** tooth profile surface roughness was considered,and its evolution during repeated meshing was simulated using the Archard wear *** fatigue damage accumulation of material points on and underneath the contact surface was captured using the Brown-Miller-Morrow multiaxial fatigue *** elastic-plastic constitutive behavior of damaged material points was updated by incorporating the damage *** in the wear depth and fatigue damage around the pitch point are described,and the effect of surface roughness on the fatigue life is *** results reveal that whether fatigue failure occurs initially on the surface or sub-surface depends on the level of surface *** wear on the asperity level alleviates the local stress concentration and leads to a longer surface fatigue life compared with the result without wear.

关键词： gear contact fatigue tooth wear surface roughness damage accumulation