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Virtual Simulation System with Path-following Control for Lunar Rovers Moving on Rough Terrain

Chinese Journal of Mechanical Engineering 2012年第1期25卷 38-46页

作者： GAO Haibo DENG Zongquan DING Liang WANG mengyu State Key Laboratory of Robotics and Systems Harbin Institute of TechnologyHarbin 150001China School of Mechatronics Harbin Institute of TechnologyHarbin 150001China

Virtual simulation technology is of great importance for the teleoperation of lunar rovers during the exploration phase, as well as the design of locomotion systems, performance evaluation, and control strategy verification during the R&D phase. The currently used simulation methods for lunar rovers have several disadvantages such as poor fidelity for wheel-soil interaction mechanics, difficulty in simulating rough terrains, and high complexity making it difficult to realize mobility control in simulation systems. This paper presents an approach for the construction of a virtual simulation system that integrates the features of 3D modeling, wheel-soil interaction mechanics, dynamics analysis, mobility control, and visualization for lunar rovers. Wheel-soil interaction experiments are carried out to test the forces and moments acted on a lunar rover’s wheel by the soil with a vertical load of 80 N and slip ratios of 0, 0.03, 0.05, 0.1, 0.2, 0.3, 0.4, and 0.6. The experimental results are referenced in order to set the parameters’ values for the PAC2002 tire model of the ADAMS/Tire module. In addition, the rough lunar terrain is simulated with 3DS Max software after analyzing its characteristics, and a data-transfer program is developed with Matlab to simulate the 3D reappearance of a lunar environment in ADAMS. The 3D model of a lunar rover is developed by using Pro/E software and is then imported into ADAMS. Finally, a virtual simulation system for lunar rovers is developed. A path-following control strategy based on slip compensation for a six-wheeled lunar rover prototype is researched. The controller is implemented by using Matlab/Simulink to carry out joint simulations with ADAMS. The designed virtual lunar rover could follow the planned path on a rough terrain. This paper can also provide a reference scheme for virtual simulation and performance analysis of rovers moving on rough lunar terrains.

关键词： lunar rover comprehensive simulation system rough terrain wheel-soil interaction mechanics path-following control

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Assessment of genetic variation in tomato (Solanum lycopersicum L.) inbred lines using SSR molecular markers

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Journal of Genetics and Genomics 2008年第6期35卷 373-379页

作者： Solomon Benor mengyu Zhang Zhoufei Wang Hongsheng Zhang State Key Lab of Crop Genetics and Germplasm Enhancement College ofAgriculture Nanjing Agricultural University Nanjing 210095 China Department of Agrobiodiversity Institute of Crop Science University of Kassel 34109 Kassel Germany and Leibniz Institute of Plant Genetics and Crop Plant Research （IPK） Corrensstr. 3 06466 Gatersleben Germany

A study was conducted to determine the genetic diversity of 39 determinate and indeterminate tomato inbred lines collected from China, Japan, S. Korea, and USA. Using 35 SSR polymorphic markers, a total of 150 alleles were found with moderate levels of diversity, and a high number of unique alleles existing in these tomato lines. The mean number of alleles per locus was 4.3 and the average polymorphism information content （PIC） was 0.31. Unweighted Pair Group Method with Arithmetic Mean （UPGMA） clustering at genetic similarity value of 0.85 grouped the inbred lines into four groups, where one USA cultivar formed a separate and more distant cluster. The most similar inbred lines are from USA, both with determinate type, whereas the most different lines are from USA （Us-16） and Japan （Ja-2） with determinate and indeterminate growth habit, respectively. Clustering was consistent with the known information regarding geographical location and growth habit. The genetic distance information reported in this study might be used by breeders when planning future crosses among these inbred lines.

关键词： Solanum lycopersicum L SSR markers genetic diversity growth characterization

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A Pair-Electrosynthesis for Formate at Ultra-Low Voltage Via Coupling of CO_(2) Reduction and Formaldehyde Oxidation

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Nano-Micro Letters 2022年第12期14卷 415-431页

作者： mengyu Li Tehua Wang Weixing Zhao Shuangyin Wang Yuqin Zou State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringAdvanced Catalytic Engineering Research Center of the Ministry of EducationHunan UniversityChangsha 410082People’s Republic of China School of Chemistry and Chemical Engineering Jishou UniversityJishou 416000HunanPeople’s Republic of China

Formate can be synthesized electrochemically by CO_(2) reduction reaction(CO_(2)RR)or formalde-hyde oxidation reaction(FOR).The CO_(2)RR approach suffers from kinetic-sluggish oxygen evolution reac-tion at the *** this end,an electrochemical sys-tem combining cathodic CO_(2)RR with anodic FOR was developed,which enables the formate electrosynthesis at ultra-low *** CO_(2)RR employing the BiOCl electrode in H-cell exhibited formate Faradaic efficiency(FE)higher than 90% within a wide potential range from−0.48 to−1.32 V_(RHE).In flow cell,the current density of 100 mA cm^(−2) was achieved at−0.67 V_(RHE).The anodic FOR using the Cu_(2)O electrode displayed a low onset potential of−0.13 V_(RHE) and nearly 100%formate and H_(2) selectivity from 0.05 to 0.35 V_(RHE).The CO_(2)RR and FOR were constructed in a flow cell through membrane electrode assembly for the electrosynthesis of formate,where the CO_(2)RR//FOR delivered an enhanced current density of 100 mA cm^(−2) at 0.86 *** work provides a promising pair-electrosynthesis of value-added chemicals with high FE and low energy consumption.

关键词： Formate pair-electrolysis Electrochemical CO_(2)reduction Formaldehyde oxidation reaction Membrane electrode assembly Flow cell

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All-small-molecule dynamic covalent gels with antibacterial activity by boronate-tannic acid gelation

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Chinese Chemical Letters 2020年第3期31卷 869-874页

作者： Xuejing Cheng mengyu Li Hui Wang Yiyun Cheng Shanghai Key Laboratory of Regulatory Biology School of Life SciencesEast China Normal UniversityShanghai 200241China South China Advanced Institute for Soft Matter Science and Technology South China University of TechnologyGuangzhou 510640China

Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or *** construction of these functional materials usually requires the pre-synthesis of macro molecular building blocks,and direct gelation between natural polyphenols and small molecule boranic acids is yet to be *** this study,we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic *** and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural *** gels showed multi-responsiveness,such as acid-,base-,reduction-and oxidantsensitive depending on the used boronic acid building *** chemistry for gel formation and stimuli-responsiveness was characterized by11B NMR *** multi-stimuli responsiveness,green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.

关键词： Nature polyphenols Boronic acids Hydrogels Boronate-catechol complexation All-small-molecule dynamic covalent gels

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Kinematic calibration method with high measurement efficiency and robust identification for hybrid machine tools

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Chinese Journal of Aeronautics 2024年第3期37卷 468-482页

作者： Liping WANG mengyu LI Guang YU Weitao LI Xiangyu KONG State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Key Laboratory of Precision/Ultra-precision Manufacturing Equipment and Control Beijing 100084China

Geometric error is the main factor affecting the machining accuracy of hybrid machine *** calibration is an effective way to improve the geometric accuracy of hybrid machine *** necessity to measure both position and orientation at each pose,as well as the instability of identification in case of incomplete measurements,severely affects the application of traditional calibration *** this study,a kinematic calibration method with high measurement efficiency and robust identification is proposed to improve the kinematic accuracy of a five-axis hybrid machine ***,the configuration is introduced,and an error model is ***,by investigating the mechanism error characteristics,a measurement scheme that only requires tool centre point position error measurement and one alignment operation is ***,by analysing the effects of unmeasured degrees of freedom(DOFs)on other DOFs,an improved nonlinear least squares method based on virtual measurement values is proposed to achieve stable parameter identification in case of incomplete measurement,without introducing additional ***,the proposed calibration method is verified through simulations and *** proposed method can efficiently accomplish the kinematic calibration of the hybrid machine *** accuracy of the hybrid machine tool is significantly improved after calibration,satisfying actual aerospace machining requirements.

关键词： Hybrid machine tool Calibration Measurement scheme Improved nonlinear least squares method Virtual measurement values

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Urban residents'behavioral response to climate change and its influencing factors:A case study of Tianjin,China

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Chinese Journal of Population,Resources and Environment 2020年第3期18卷 188-195页

作者： Yong Liu mengyu Zhang School of Economics Sichuan UniversityChengdu610065China

Climate change is a global issue that poses a significant risk to the global economy and therefore warrants coordinated collective *** a questionnaire survey in China,this study presents urban residents'behavioral response to climate change and its influencing *** results indicated that urban residents in Tianjin often took low-cost,intuitive,and quickly implementable actions,namely behavioral coping *** adaptive behavior was also evident,which involved greater financial ***,according to regression analysis results of urban residents'behavior and its influencing factors,knowledge of climate change manifested a positive correlation with urban residents'behavioral coping *** contrast,cost manifested a negative correlation with urban residents'proactive adaptive behavior,which was a more complex,costly,and challenging anticipatory *** of climate change manifested a positive correlation with both behavioral coping response and proactive adaptive ***,recommendations for encouraging beneficial behaviors among urban residents are suggested.

关键词： Climate change Behavioral coping response Proactive adaptive behavior

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Iterative Android automated testing

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Frontiers of Computer Science 2023年第5期17卷 15-26页

作者： Yi ZHONG mengyu SHI Youran XU Chunrong FANG Zhenyu CHEN State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210093China School of Big Data and Computer Science Chongqing College of Mobile CommunicationChongqing 400065China

With the benefits of reducing time and workforce,automated testing has been widely used for the quality assurance of mobile applications(APPs).Compared with automated testing,manual testing can achieve higher coverage in complex interactive *** the effectiveness of manual testing is highly dependent on the user operation process(UOP)of experienced *** on the UOP,we propose an iterative Android automated testing(IAAT)method that automatically records,extracts,and integrates UOPs to guide the test logic of the tool across the complex Activity *** feedback test results can train the UOPs to achieve higher coverage in each *** extracted 50 UOPs and conducted experiments on 10 popular mobile APPs to demonstrate IAAT’s effectiveness compared with Monkey and the initial automated *** experimental results show a noticeable improvement in the IAAT compared with the test logic without human *** the 60 minutes test time,the average code coverage is improved by 13.98%to 37.83%,higher than the 27.48%of Monkey under the same conditions.

关键词： quality assurance automated testing UOP test coverage

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WDBM: Weighted Deep Forest Model Based Bearing Fault Diagnosis Method

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Computers, Materials & Continua 2022年第9期72卷 4741-4754页

作者： Letao Gao Xiaoming Wang Tao Wang mengyu Chang Department of Computer Science City University of Hong KongHong Kong999077China School of Computer and Software Engineer Xihua UniversityChengdu610039China Nanjing University of Aeronautics and Astronautics Nanjing210008China McGill University MontrealH3G 1Y2Canada

In the research field of bearing fault diagnosis,classical deep learning models have the problems of too many parameters and high computing *** addition,the classical deep learning models are not effective in the scenario of small *** recent years,deep forest is proposed,which has less hyper parameters and adaptive depth of deep *** addition,weighted deep forest(WDF)is proposed to further improve deep forest by assigning weights for decisions trees based on the accuracy of each decision *** this paper,weighted deep forest model-based bearing fault diagnosis method(WDBM)is *** WDBM is regard as a novel bearing fault diagnosis method,which not only inherits the WDF’s advantages-strong robustness,good generalization,less parameters,faster convergence speed and so on,but also realizes effective diagnosis with high precision and low cost under the condition of small *** verify the performance of the WDBM,experiments are carried out on Case Western Reserve University bearing data set(CWRU).Experiments results demonstrate that WDBM can achieve comparative recognition accuracy,with less computational overhead and faster convergence speed.

关键词： Deep forest bearing fault diagnosis weights

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The Useof Drama Pedagogy in Teaching Morality in a Chinese Primary School

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ECNU Review of Education 2022年第2期5卷 219-241页

作者： mengyu Feng Capital Normal University

Purpose:This paper aims to explore the potential of the drama pedagogy that may contribute to primary children's moral growth in the Chinese educational *** argues that drama may offer an ensemble-based,dialogic,and narrative pedagogy for teaching morality to complement thedidactic traditional ***/Approach/Methods:The methodological approach is that of case study research,using different methods to assess the effects and effectiveness of the author's *** fieldwork was undertaken in a public primary school in Beijing,in which the drama workshop The Boat was taught to I6 children on a voluntary ***:The study demonstrates that drama can be seen to some extent to assist pupils in aspects of their empathetic attitudes,dialogic thinking abilities,and autonomous thinking ***/Value:The author hopes the study might stimulate more and deeper research in similar contexts and that this may further extend the understanding of Chinese teachers of this resourceful new pedagogy.

关键词： China drama pedagogy moral education primary school education story

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The Impact of City Cluster Development on the Inter-City Disparity:Evidence from China

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Chinese Journal of Urban and Environmental Studies 2022年第1期10卷 96-118页

作者： YANG mengyu HU Bingxuan The School of Economics Yunnan University

City clusters are important carriers for China's future urbanization and vital areas for promotingcoordinated regional development and common prosperity. The authors first divide the city clusters into Types Ⅰ, Ⅱ, and Ⅲ according to the characteristics of their development stages, and measure the degree of development of city clusters by using city-level night time light(NTL) data and inter-city commuting time, and empirically identify the types of China's city clusters. On that basis, the authors examine the influence of city cluster development on the inter-city disparity from a perspective of urban agglomeration. The results show that the development of Type Ⅰ city clusters can lead to the widest inter-city disparity, and that of Type Ⅱ city clusters ranks the second place in this regard, while that of Type Ⅲ city clusters can narrow the inter-city ***, using the 268-year historical geographic data of the Qing Dynasty, the authors construct instrumental variables to address the endogeneity issues, and find that the above conclusions are robust. This study also finds that the factor allocation for the development of Types Ⅰ and Ⅱ city clusters is oriented towards labor, while that for Type Ⅲ city clusters is oriented towards capital. Besides, different types of city clusters vary in the extent of correcting factor misallocation for their development. The differences in the orientation of factor allocation and the extent of factor misallocation correction constitute the main mechanism for the heterogeneous influence of city cluster development on the inter-city disparity. China's city cluster development strategy should adopt a category-based approach to avoid homogenization, conform to the objective laws, and make greater use of central cities' spatial spillover effects.

关键词： City cluster inter-city disparity nighttime light

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