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Sustainable Intensification and Large-scale Operation of Cultivated Land Use at the Farmers’ Scale:A Case Study of Shandong Province,China

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Chinese Geographical Science 2024年第1期34卷 149-167页

作者： LI Li lyu Xiao ZHANG Anlu NIU Shandong PENG Wenlong School of Public Administration Huazhong Agricultural UniversityWuhan430070China Department of Geography University of ZurichZurich8057Switzerland School of Humanities and Law Northeastern UniversityShenyang110169China School of Geography and Tourism Qufu Normal UniversityRizhao276800China

Sustainable intensification of cultivated land use(SICLU) and large-scale operations(LSO) are widely acknowledged strategies for enhancing agricultural ***,the existing literature has faced challenges in precisely defining SICLU and constructing comprehensive indicators,which has hindered the exploration of factors influencing LSO within the SICLU *** address this gap,we integrated self-efficacy theory into the design of an index framework for evaluating *** subsequently employed econometric models to analyze the significant factors that impact *** findings reveal that SICLU can be divided into four key dimensions:intensive management,efficient output,resource conservation,and ecological environment ***,it is crucial to incorporate belief-based cognitive factors into the index system,as farmers’ understanding of fertilizer and pesticide application significantly influences their willingness to engage in ***,we identify grain market turnover as the most influential factor in promoting LSO,with single-factor contribution rates reaching 70.9% for cultivated land transfer willingness and 62.5% for the total planting ***,unlike irrigation and agricultural machinery inputs,increased labor inputs correspond to larger planting areas for *** trend may be attributed to reduced labor availability because of rural labor migration,whereas the reduction in irrigation and agricultural input is contingent on innovations in production practices and the transfer of cultivated land management ***,SICLU dynamically influences LSO,with each index related to SICLU having an optimal range that fosters *** insights offer valuable guidance for policymakers,emphasizing farmers as their central focus,with the adjustment of input and output factors as a means to achieve LSO as the ultimate *** conclusion,we propose research avenues for further enriching the SICLU framework to ensur

关键词： sustainable intensification of cultivated land use(SICLU) self-efficacy status quo bias input and output Boosted Regression Tree willingness to transfer cultivated land cultivated land planting areas Shandong,China

Stackelberg Game for Wireless Powered and Backscattering Enabled Sensor Networks

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China Communications 2024年第3期21卷 189-204页

作者： lyu Bin Cao Yi Wang Shuai Guo Haiyan Hao Chengyao Key Laboratory of Ministry of Education in Broadband Wireless Communication and Sensor Network Technology Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Engineering Research Center of Novel Optical Fiber Technology and Communication Network Suzhou 215006China Guangdong-Hong Kong-Macao Joint Laboratory of Human-Machine Intelligence-Synergy Systems Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

This paper investigates a wireless powered and backscattering enabled sensor network based on the non-linear energy harvesting model, where the power beacon(PB) delivers energy signals to wireless sensors to enable their passive backscattering and active transmission to the access point(AP). We propose an efficient time scheduling scheme for network performance enhancement, based on which each sensor can always harvest energy from the PB over the entire block except its time slots allocated for passive and active information delivery. Considering the PB and wireless sensors are from two selfish service providers, we use the Stackelberg game to model the energy interaction among them. To address the non-convexity of the leader-level problem, we propose to decompose the original problem into two subproblems and solve them iteratively in an alternating manner. Specifically, the successive convex approximation, semi-definite relaxation(SDR) and variable substitution techniques are applied to find a nearoptimal solution. To evaluate the performance loss caused by the interaction between two providers, we further investigate the social welfare maximization problem. Numerical results demonstrate that compared to the benchmark schemes, the proposed scheme can achieve up to 35.4% and 38.7% utility gain for the leader and the follower, respectively.

关键词： backscatter communication energy interaction stackelberg game wireless powered sensor network

Sensing Matrix Optimization for Random Stepped-Frequency Signal Based on Two-Dimensional Ambiguity Function

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Chinese Journal of Electronics 2024年第1期33卷 161-174页

作者： Mingjiu lyu Hao CHEN Jun YANG Xia WU Ming ZHOU Xiaoyan MA Radar NCO School Air Force Early Warning Academy Department of Early Warning Technology Air Force Early Warning Academy

Compressive sensing technique has been widely applied to achieve range-Doppler reconstruction of high frequency radar by utilizing sparse random stepped-frequency(SRSF) signal, which can suppress the complex electromagnetic interference and greatly reduce the coherent processing interval. An important way to improve the performance of sparse signal reconstruction is to optimize the sensing matrix(SM). However, the existing research on the SM optimization needs to design a measurement matrix with superior performance, which needs a large amount of computation and does not consider the influence of the waveform parameters design. In order to improve the superior reconstruction performance, a novel SM optimization approach for SRSF signal is proposed by using two-dimensional ambiguity function(TDAF) in this paper. Firstly, based on the two-dimensional sparse reconstruction model of the SRSFs, the internal relationship between the waveform parameters and the SM was derived. Secondly, the SM optimization problem was directly transformed into the waveform design of SRSFs. Furthermore, on the basis of analyzing the relationship between the mutual coherence matrix of SM and the TDAF matrix of SRSFs, the purpose of optimizing the SM can be achieved by designing the TDAF of the SRSFs. Based on this analysis, a sparse waveform optimization method with joint constraints of maximum and mean sidelobes of the TDAF by using the genetic algorithm was derived. Compared with the traditional SM optimization method, our method not only avoids generating a new measurement matrix, but also further reduces the complexity of the waveform optimization. Simulation experiments verified the effectiveness of the proposed method.

关键词： Correlation Computational modeling Electromagnetic interference Optimization methods Signal reconstruction High frequency radar Sensors

Long-Term Performance and Microstructural Characterization of Dam Concrete in the Three Gorges Project

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Engineering 2024年第2期33卷 237-262页

作者： Chen lyu Cheng Yu Chao Lu Li Pan Wenwei Li Jiaping Liu School of Materials Science and Engineering Southeast UniversityNanjing 211189China State Key Laboratory of High Performance Civil Engineering Materials Sobute New Materials Co.Ltd.Nanjing 211103China China Three Gorges Corporation Wuhan 430010China

This study investigates the long-term performance of laboratory dam concrete in different curing environments over ten years and the microstructure of 17-year-old laboratory concrete and actual concrete cores drilled from the Three Gorges *** mechanical properties of the laboratory dam concrete,whether cured in natural or standard environments,continued to improve over ***,the laboratory dam concrete exhibited good resistance to diffusion and a refined microstructure after 17 ***,curing and long-term exposure to the local natural environment reduced the frost *** analyses of the laboratory concrete samples demonstrated that moderate-heat cement and fine fly ash(FA)particles were almost fully hydrated to form compact micro structures consisting of large quantities of homogeneous calcium(alumino)silicate hydrate(C-(A)-S-H)gels and a few *** obvious interfacial transition zones were observed in the microstructure owing to the longterm pozzolanic *** dense and homogenous microstructure was the crucial reason for the excellent long-term performance of the dam concrete.A high FA volume also played a significant role in the microstructural densification and performance growth of dam concrete at a later *** concrete drilled from the dam surface exhibited a loose microstructure with higher microporosity,indicating that concrete directly exposed to the actual service environment suffered degradation caused by water and wind *** this study,both macro-performance and microstructural analyses revealed that the application of moderate-heat cement and FA resulted in a dense and homogenous microstructure,which ensured the excellent long-term performance of concrete from the Three Gorges Dam after 17 ***-term exposure to an actual service environment may lead to microstructural degradation of the concrete ***,the retained long-term dam concrete samples need to be further researched to

关键词： Three Gorges Dam Long-term performance Microstructural analysis Moderate-heat cement Fly ash

Effects of the inlet particle spatial distribution on the performance of a gas-solid cyclone separator

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Particuology 2024年第2期85卷 133-145页

作者： Yuge Yao Manxia Shang Xiwei Ke Zhong Huang Tuo Zhou Junfu lyu Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Energy and Power EngineeringTsinghua UniversityBeijing100084China

The present study was aimed at the inlet particle spatial distribution of a gas-solid separator with high solid loading and investigated its effects on cyclone performance and the inner flow *** flow fields of a cyclone with different rectangular particle flow areas on the inlet surface were numerically simulated using a four-way coupling *** simulated results indicate that reducing the inlet particle flow area and lowing the inlet particle position can effectively reduce the scattered particles inside the cyclone separator and enhance the separation *** gathering the particles to the centerline can also weaken the particle *** particles near the roof account for the swirling particle ceiling *** inlet particle spatial distribution affects the pressure drop mainly by affecting the gas tangential velocity in the cylinder ***,compared to the hori-zontal particle distribution on the inlet surface,the vertical particle distribution has greater effects on cyclone performance.

关键词： Gas-solid cyclone Inlet particle spatial distribution Four-way coupling Separation efficiency Scattered particle

Observer-Based Adaptive Robust Precision Motion Control of a Multi-Joint Hydraulic Manipulator

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1213-1226页

作者： Zheng Chen Shizhao Zhou Chong Shen Litong lyu Junhui Zhang Bin Yao State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027 Ocean College Zhejiang UniversityZhoushan 316021China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050000 State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China School of Mechanical Engineering Purdue UniversityWest LafayetteIN 47907 USA

Hydraulic manipulators are usually applied in heavy-load and harsh operation ***,when faced with a complex operation,the traditional proportional-integral-derivative(PID)control may not meet requirements for high control ***-based full-state-feedback control is an effective alternative,but the states of a hydraulic manipulator are not always available and reliable in practical applications,particularly the joint angular velocity *** that it is not suitable to obtain the velocity signal directly from differentiating of position measurement,the low-pass filtering is commonly used,but it will definitely restrict the closed-loop bandwidth of the whole *** avoid this problem and realize better control performance,this paper proposes a novel observerbased adaptive robust controller(obARC)for a multi-joint hydraulic manipulator subjected to both parametric uncertainties and the lack of accurate velocity ***,a nonlinear adaptive observer is first designed to handle the lack of velocity measurement with the consideration of parametric ***,the adaptive robust control is developed to compensate for the dynamic uncertainties,and the close-loop system robust stability is theoretically proved under the observation and control ***,comparative experiments are carried out to show that the designed controller can achieve a performance improvement over the traditional methods,specifically yielding better control accuracy owing to the closed-loop bandwidth breakthrough,which is limited by low-pass filtering in fullstate-feedback control.

关键词： handle Observer filtering

基于Monte Carlo的聚焦型X射线脉冲星望远镜多物理场耦合分析方法

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航空学报 2016年第4期37卷 1249-1260页

作者：李连升邓楼楼梅志武吕政欣刘继红左富昌北京控制工程研究所北京100190 北京航空航天大学机械工程及自动化学院北京100083

聚焦型X射线脉冲星望远镜(XPT)是涉及光学、机械学、热学等多学科的复杂航天载荷,多物理场耦合分析对提高其在轨性能和可靠性至关重要。传统的光机热多场耦合分析(MCA)方法并不能考虑X射线能量及其反射率信息,而且存在学科间数据传递困... 详细信息

聚焦型X射线脉冲星望远镜(XPT)是涉及光学、机械学、热学等多学科的复杂航天载荷,多物理场耦合分析对提高其在轨性能和可靠性至关重要。传统的光机热多场耦合分析(MCA)方法并不能考虑X射线能量及其反射率信息,而且存在学科间数据传递困难的问题。为此,首先基于Monte Carlo和X射线全反射理论提出了一种高效的多物理场耦合分析方法。该方法同时考虑X射线能量和反射率两大特征信息,基于有限元分析(FEA)法建立了XPT热-结构物理场耦合方程和有限元分析模型,针对不同工况进行热分析、结构分析以及热-结构物理场耦合分析。其次,采用Construction Geometry函数分别提取不同工况下光学镜头面形的形变量,并基于多项式函数对变形后的镜头面形进行拟合和误差分析。然后,基于所提方法对变形后的光学系统聚焦性能进行分析与评价,得到镜头形变对XPT光学聚焦性能的影响规律。最后,以多层嵌套的XPT为例,对不同视场角和形变的X射线光学系统聚焦性能进行了仿真分析。结果表明,在全视场时热-结构耦合形变、热形变及结构形变导致XPT聚焦性能分别下降30.01%,14.35%和7.85%,弥散斑均方根依次为2.914 3mm,2.603 8mm,2.531 1 mm。通过与试验结果对比分析,验证了所提方法的有效性,可用于XPT的可靠性设计。

关键词： Monte Carlo 聚焦 X射线脉冲星望远镜多物理场耦合有限元分析法

Power Generation Enhancement in a Solar Energy and Biomass-Based Distributed Energy System using H_(2)O/CO_(2)Hybrid Gasification

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Journal of Thermal Science 2024年第5期33卷 1657-1671页

作者： WU Haifeng lyu Yan WANG Ruixiang XU Rongji QU Wanjun LIU Qibin Beijing Engineering Research Center of Sustainable Energy and Buildings Beijing University of Civil Engineering and ArchitectureBeijing 100044China Guangdong Provincial Key Laboratory of Distributed Energy Systems School of Chemical Engineering and Energy TechnologyDongguan University of TechnologyDongguan 523808China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China

A new solar energy and biomass-based distributed energy system using H_(2)O/CO_(2)hybrid gasification is proposed,and their complementarity to enhance the system's energy efficiency is investigated and *** the system,concentrated solar energy is used to provide heat for biomass gasification;two gasifying agents(H_(2)O and CO_(2))are adopted to enhance syngas yields,and the produced solar fuel is further burned for power production in a combined cycle *** show that CO share in gasification products is remarkably increased with the increment of CO_(2)/H_(2)O mole ratio caused by the boudouard reaction with the consumption of fixed carbon,while the H_(2)share is decreased;the optimal solar-to-fuel efficiency,27.88%,is achieved when the temperature and CO_(2)/H_(2)O mole ratio are 1050℃and 0.45,*** emission reduction rate of CO_(2)in the system under design conditions is reduced by 2.31%compared with that using only H_(2)O *** annual power production of the system is increased by 1.39%,and the thermodynamic and environmental performances are significantly ***,an economic assessment is conducted to forecast the technical feasibility of the hybrid gasification *** work provides a promising route to improving the thermochemical utilization efficiency of solar energy and solid fuel.

关键词： solar energy biomass hybrid gasification distributed energy system thermodynamics performance

Multiparameter Numerical Investigation of Two Types of Moving Interactions Between the Deep-Sea Mining Vehicle Track Plate and Seabed Soil:Digging and Rotating Motions

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China Ocean Engineering 2024年第3期38卷 408-423页

作者： SUN Peng-fei lyu Hai-ning YANG Jian-min XU Zhi-yong State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China Yazhou Bay Institute of Deepsea SCI-TECH Shanghai Jiao Tong UniversitySanya 572024China Institute of Marine Equipment Shanghai Jiao Tong UniversityShanghai 200240China

To ensure the safe performance of deep-sea mining vehicles(DSMVs),it is necessary to study the mechanical characteristics of the interaction between the seabed soil and the track *** rotation and digging motions of the track plate are important links in the contact between the driving mechanism of the DSMV and seabed *** this study,a numerical simulation is conducted using the coupled Eulerian–Lagrangian(CEL)large deformation numerical method to investigate the interaction between the track plate of the DSMV and the seabed soil under two working conditions:rotating condition and digging ***,a soil numerical model is established based on the elastoplastic mechanical characterization using the basic physical and mechanical properties of the seabed soil obtained by in situ ***,the soil disturbance mechanism and the dynamic mechanical response of the track plate under rotating and digging conditions are obtained through the analysis of the sensitivity of the motion parameters,the grouser structure,the layered soil features and the soil *** results indicate that the above parameters remarkably influence the interaction between the DSMV and the seabed ***,it is important to consider the rotating and digging motion of the DSMV in practical engineering to develop a detailed optimization design of the track plate.

关键词： deep-sea mining vehicle rotating motion digging motion track plate-seabed soil interaction CEL numerical method