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Control Theory and Technology 2025年

作者： Liu, Qifang Sun, Dazhen Chen, Haowen Li, Dongzi Wang, Ping Department of Control Science and Engineering Jilin University Jilin Changchun130022 China State Key Laboratory of Automotive Simulation and Control Jilin University Jilin Changchun130022 China

In this article, the received, revised and accepted dates are missing. Please find the correct history dates here: Received: 15 October 2023. Revised: 20 March 2024. Accepted: 6 May 2024. © The Author(s), under exclusive licence to South China University of Technology and Academy of Mathematics and Systems science, Chinese Academy of sciences 2025.

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Analytical Delta-V Approximation for Nonlinear Programming of Multi-target Rendezvous and Flyby Trajectories

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arXiv 2024年

作者： Huang, An-Yi Li, Heng-Nian Luo, Ya-Zhong State Key Laboratory of Astronautic Dynamics Xi’an710043 China National University of Defense Technology Changsha410073 China College of Aerospace Science and Engineering Hunan Key Laboratory of Intelligent Planning and Simulation for Aerospace Missions China

This study proposes an analytical Delta-V approximation of short-timetransfers based on the linear relative motion and a gradient-based nonlinear programming model of multi-target rendezvous and fly by trajectories. In previous studies, the Lambert's solution is commonly used to evaluate Delta-Vof short-duration transfers. In this study, to avoid the iteration process forobtaining the Lambert's solution and its gradient, the linear relative motion equations are applied to form an analytical two-point boundary value model for the near-circular orbit rendezvous problems. Although the relative motion equations are usually applicable when the two orbits are close enough, and the position and velocity errors would become more significant as the orbital differences increase, the errors of the velocity increments were proved acceptable in our simulations. Moreover, the analytical formula facilitates the calculation of the gradients to the start epoch and flight time, which are used to establish a nonlinear programming model for sequence optimization that gradient-based algorithms can easily solve. simulation results demonstrated that the analytical Delta-V approximation requires much less calculation than the Lambert's solution, and the proposed gradient-based nonlinear programming algorithms can obtain similar results in less time than previous methods. Copyright © 2024, The Authors. All rights reserved.

关键词： Nonlinear programming

Partial-Wetting Phenomena in Active Matter

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arXiv 2025年

作者： Zhang, Jing Liu, Zhixin Zhao, Shengda Yan, Yangjun Yue, Rongxin Yu, Jiaxin Li, Xinjie Zhang, Xinghua School of Physical Science and Engineering Beijing Jiaotong University Beijing100044 China Beijing Key Laboratory of Novel Materials Genetic Engineering and Application for Rail Transit Beijing Jiaotong University Beijing100044 China School of Science Key Laboratory of High Performance Scientific Computation Xihua University Chengdu610039 China

Abundant interfacial phenomena in nature, such as water droplets on lotus leaves and water transport in plant vessels—originate from partial-wetting phenomena, which can be well described by Young’s equation. It remains an intriguing question whether similar behaviors exist in active matter. In this letter, we present a clear demonstration of the partial-wetting phenomenon in a ternary laning system, which is a typical active system. A phase diagram is constructed in which the relative drift velocities of different components govern the transitions among drying, partial wetting, and complete wetting states. The mechanical balance on the contact lines of the partial-wetting phase described by Young’s equation is verified. A theoretical picture is proposed to explain the analogy of partial wetting in the laning system to that in the equilibrium system. © 2025, CC BY.

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γ-DEEPDSM FOR INTERFACE RECONSTRUCTION: OPERATOR LEARNING AND A LEARNING-AUTOMATED FEM PACKAGE

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arXiv 2024年

作者： Zheng, Yangyang Wei, Huayi Cao, Shuhao Guo, Ruchi School of Mathematics and Computational Science Xiangtan University Hunan Xiangtan China School of Mathematics and Computational Science Xiangtan University National Center for Applied Mathematics in Hunan Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan411105 China School of Science and Engineering University of Missouri-Kansas City Kansas CityMO United States School of Mathematics Sichuan University Sichuan Chengdu China

In this work, we propose an Operator Learning (OpL) method for solving boundary value inverse problems in partial differential equations (PDEs), focusing on recovering diffusion coefficients from boundary data. Inspired by the classical Direct Sampling Method (DSM), our operator learner, named γ-deepDSM, has two key components: (1) a data-feature generation process that applies a learnable fractional Laplace-Beltrami operator to the boundary data, and (2) a convolutional neural network that operates on these data features to produce reconstructions. To facilitate this workflow, leveraging FEALPy [52], a cross-platform Computed-Aided-engineering engine, our another contribution is to develop a set of finite element method (FEM) modules fully integrated with PyTorch, called Learning-Automated FEM (LA-FEM). The new LA-FEM modules in FEALPy conveniently allows efficient parallel GPU computing, batched computation of PDEs, and auto-differentiation, without the need for additional loops, data format conversions, or device-to-device transfers. With LA-FEM, the PDE solvers with learnable parameters can be directly integrated into neural network models. Copyright © 2024, The Authors. All rights reserved.

关键词： Convolutional neural networks

Identifying Differences in Evapotranspiration and Ecosystem Water Use Efficiency between Different Types of Urban Green Spaces: A Case Study of the Main Urban Area of Beijing

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SSRN

SSRN 2024年

作者： Shao, Rui Li, Jiaqi Shao, Weiwei Wang, Yicheng State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing100038 China State Key Laboratory of Hydro science and Engineering Department of Hydraulic Engineering Tsinghua University Beijing100084 China

Study RegionThe main urban area of Beijing, *** FocusRefined modeling is crucial for estimating carbon sequestration and water consumption in urban green spaces. This study used Sentinel-2 data, PT-JPLim, and WUE models to estimate monthly ET and WUE in Beijing’s main urban area (2016–2021) at a 10 × 10 m resolution. Machine learning quantified the effects of environmental factors on ET and WUE across various green space types. simulations assessed the impacts of different vegetation scenarios on ET and WUE, while urban ET and WUE were predicted for 2022–2100 under different climate scenarios using *** Hydrological Insights for the RegionThis study shows that vegetation, especially LAI, is the primary driver of spatiotemporal variations in ET and WUE across Beijing's urban green spaces, contributing 64.7% and 62.5% to their changes, respectively. simulations of a 25% vegetation increase revealed that residential green spaces are most sensitive, with ET and WUE rising by 6.2% and 30%. The study estimated water requirements, with net irrigation needs of 95.18 million m³ in normal years and 125 million m³ in dry years. Projections under the SSP126 scenario indicate a near-equilibrium state for carbon sequestration and CO2 concentrations, achieving greater carbon sinks and water conservation with minimal increases in water consumption. These insights are valuable for optimizing water resource management and ecological planning in urban green spaces. © 2024, The Authors. All rights reserved.

关键词： Carbon sequestration

Phase behavior of symmetric diblock copolymers under 3D soft confinement

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arXiv 2024年

作者： He, Zhijuan Huang, Jin Jiang, Kai Shi, An-Chang School of Mathematics and Computational Science Xiangtan University Hunan Key Laboratory for Computation and Simulation in Science and Engineering Key Laboratory of Intelligent Computing and Information Processing Ministry of Education 411105 China Laboratory of Mathematics and Complex Systems Ministry of Education School of Mathematical Sciences Beijing Normal University Beijing100875 China Department of Physics and Astronomy McMaster University HamiltonONL8S 4M1 Canada

The phase behavior of symmetric diblock copolymers under three-dimensional (3D) soft confinement is investigated using the self-consistent field theory. The soft confinement is realized in binary blends composed AB diblock copolymers and C homopolymers, where the copolymers self-assemble to form a droplet embedded in the homopolymer matrix. The phase behavior of the confined block copolymers is regulated by the degree of confinement and the selectivity of the homopolymers, resulting in a rich variety of novel structures. When the C homopolymers are neutral to the A- and B-blocks, stacked lamellae (SL) are formed where the number of layers increases with the droplet volume, resulting in a morphological transition sequence from Janus particle to square SL. When the C homopolymers are strongly selective to the B-blocks, a series of non-lamellar morphologies, including onion-, hamburger-, cross-, ring-, and cookie-like structures, are observed. A detailed free energy analysis reveals a first-order reversible transformation between SL and onion-like (OL) structures when the selectivity of the homopolymers is changed. Our results provide a comprehensive understanding of how various factors, such as the copolymer concentration, homopolymer chain length, degree of confinement, homopolymer selectivity, affect the self-assembled structures of diblock copolymers under soft 3D confinement. Copyright © 2024, The Authors. All rights reserved.

关键词： Free energy

Revealing the Response of Evapotranspiration and Water Use Efficiency to Vegetation Changes in Different Types of Urban Green Spaces

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SSRN

SSRN 2024年

作者： Shao, Rui Shao, Weiwei Wang, Yicheng Ni, Guangheng State Key Laboratory of Hydro science and Engineering Department of Hydraulic Engineering Tsinghua University Beijing100084 China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing100038 China

The quantification of urban water‒carbon change is critical to our ability to assess urban water resource effectiveness and quantify urban ecological processes. In this study, we used Sentinel-2 data combined with the PT‒JPLim and analytical water use efficiency (WUE) models to simulate monthly urban evapotranspiration (ET) with a spatial resolution of 10×10 m, analyzing the WUE and ET partitioning in the main urban area of Beijing from 2016 to 2021. Verification of modeled ET based on two flux towers showed that the PT‒JPLim model performed well (Daxing: R2 = 0.84, RMSE = 16.76 mm/month;Miyun: R2 = 0.83, RMSE = 22.10 mm/month). The annual mean ET and WUE in the main urban area of Beijing were 497 mm and 0.63 gC mm−1 H2O, respectively. The carbon sequestration rate (i.e., gross primary productivity) in the main urban area of Beijing significantly increased (0.074 gC m−2 d−1 yr−1), and the proportion of water utilization (i.e., ET) decreased (−19.87 mm yr−1) during the study period, which was reflected in an increase in WUE (0.029 gC mm−1 H2O yr−1). We extracted the ET and WUE of four urban green space types (park, square, residential, and scenic green spaces) based on point of interest data. Residential green space showed the largest increases in ET (6.2%) and WUE (30%) when influenced by a 25% increase in vegetation. We projected the ET and WUE of Beijing for the period 2022‒2100 based on CMIP6. The vegetation WUE (0.0512 g C mm−1 H2O yr−1) in Beijing was projected to increase by the greatest amount under a medium forcing scenario, whereas the water consumption (0.51 mm yr−1) showed a lesser increase. This study offers new insights into the refined simulation of urban ET and WUE, enabling the quantification of water consumption and carbon sequestration processes in urban green spaces. © 2024, The Authors. All rights reserved.

关键词： Evapotranspiration

Electrocatalytic oxidation of gaseous toluene in an all-solid cell using a foam Ti/Sb-SnO2/β-PbO_(2) anode

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Journal of Environmental sciences 2023年第12期134卷 77-85页

作者： Zhikun Liu Weiming Qian Min Chen Wenshuo Zhou Boying Song Bo Zhang Xiaolei Bao Qiong Tang Yongchun Liu Changbin Zhang Aerosol and Haze Laboratory Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China Hebei Technological Innovation Center for Volatile Organic Compounds Detection and Treatment in Chemical Industry Department of quality inspection and managementHebei Chemical and Pharmaceutical CollegeShijiazhuang 050026China College of Energy materials and Chemicals Leshan Normal UniversityLeshan 614000China

Mineralization of benzene,toluene,and xylene (BTX) with high efficiency at room temperature is still a challenge for the purification of indoor *** this work,a foam Ti/Sb-Sn O2/β-Pb O_(2)anode catalyst was prepared for electrocatalytically oxidizing gaseous toluene in an all-solid cell at ambient *** complex Ti/Sb-Sn O_(2)/β-Pb O_(2)anode,which was prepared by sequentially deposing Sb-Sn O_(2)and β-Pb O_(2)on a foam Ti substrate,shows high electrocatalytic oxidation efficiency of toluene (80%) at 7 hr of reaction and high CO_(2)selectivity (94.9%) under an optimized condition,i.e.,a cell voltage of 2.0 V,relative humidity of60%and a flow rate of 100 m L/*** better catalytic performance can be ascribed to the high production rate of·OH radicals from discharging adsorbed water and the inhibition of oxygen evolution on the surface of foam Ti/Sb-Sn O_(2)/β-Pb O_(2)anode when compared with the foam Ti/Sb-Sn O_(2)*** results demonstrate that prepared complex electrodes can be potentially used for electrocatalytic removal of gaseous toluene at room temperature with a good performance.

关键词： Gaseous toluene Electrocatalytic oxidation Lead dioxide Indoor air purification Solid cell

Increased southerly and easterly water vapor transport contributed to the dry-to-wet transition of summer precipitation over the Three-River Headwaters in the Tibetan Plateau

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Advances in Climate Change Research 2023年第4期14卷 502-510页

作者： Xuan LIU Ming-Xiang YANG Ning-Peng DONG Wei-Ning XIE Hong-Gang LI Zhen GUAN Fan WEN Hao WANG Deliang CHEN College of Civil Engineering Tianjin UniversityTianjin 300354China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Cooperative Innovation Center for Water Safety&Hydro Science Hohai UniversityNanjing 210098China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China Hydrology and Water Resources Survey Bureau of Hainan Province Hainan 571126China Huaneng Lancang River Hydropower INC. Kunming 650214China Regional Climate Group Department of Earth SciencesUniversity of GothenburgGothenburg S-40530Sweden

The Three-River Headwaters(TRH)region in the Tibetan Plateau is vulnerable to climate change;changes in summer(June–August)precipitation have a significant impact on water security and sustainability in both local and downstream ***,the changes in summer precipitation of different intensities over the TRH region,along with their influencing factors,remain *** this study,we used observational and ERA5 reanalysis data and employed a precipitation categorization and water vapor budget analysis to quantify the categorized precipitation variations and investigate their possible linkages with the water vapor *** results showed an increasing trend in summer precipitation at a rate of 0.9 per year(p<0.1)during 1979–2020,with a significant dry-to-wet transition in *** category‘very heavy precipitation’(10 mm d−1)contributed 65.1%of the increased summer precipitation,which occurred frequently in the northern TRH *** dry-to-wet transition was caused by the effects of varied atmospheric circulations in each *** water vapor transport through the southern boundary was responsible for the increased net water vapor flux in the western TRH region(158.2%),while southeasterly water vapor transport through the eastern boundary was responsible for the increased net water vapor flux in the central TRH(155.2%)and eastern TRH(229.2%)***,we inferred that the dry-to-wet transition of summer precipitation and the increased‘very heavy precipitation’over the TRH was caused by increased easterly and southerly water vapor transport.

关键词： Summer precipitation Three-river headwaters region Precipitation intensity Water vapor budget

Secure and Energy-efficient Unmanned Aerial Vehicle-enabled Visible Light Communication via A Multi-objective Optimization Approach

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arXiv 2024年

作者： Liu, Lingling Wang, Aimin Wu, Jing Lu, Jiao Li, Jiahui Sun, Geng College of Computer Science and Technology Jilin University Changchun130012 China Key Laboratory of Symbolic Computation and Knowledge Engineering Ministry of Education Jilin University Changchun130012 China

In this research, a unique approach to provide communication service for terrestrial receivers via using unmanned aerial vehicle-enabled visible light communication is investigated. Specifically, we take into account a unmanned aerial vehicle-enabled visible light communication scenario with multiplex transmitters, multiplex receivers, and a single eavesdropper, each of which is equipped with a single photodetector. Then, a unmanned aerial vehicle deployment multi-objective optimization problem is formulated to simultaneously make the optical power received by receiving surface more uniform, minimize the amount of information collected by a eavesdropper, and minimize the energy consumption of unmanned aerial vehicles, while the locations and transmission power of unmanned aerial vehicles are simultaneously optimized under certain constraints. Since the formulated unmanned aerial vehicle deployment multiobjective optimization problem is complex and nonlinear, it is challenging to be tackled by using conventional methods. For the purpose of solving the problem, a multi-objective evolutionary algorithm based on decomposition with chaos initiation and crossover mutation is proposed. simulation outcomes show that the proposed approach is superior to other approaches, and is efficient at improving the security and energy efficiency of visible light communication system. Copyright © 2024, The Authors. All rights reserved.

关键词： Multiobjective optimization