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arXiv 2023年

作者： Sun, Yinghan Zheng, Linfang Chen, Hua Zhang, Wei Shenzhen Key Laboratory of Control Theory and Intelligent Systems School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China School of Computer Science University of Birmingham United Kingdom

This paper studies the problem of extracting planar regions in uneven terrains from unordered point cloud measurements. Such a problem is critical in various robotic applications such as robotic perceptive locomotion. While existing approaches have shown promising results in effectively extracting planar regions from the environment, they often suffer from issues such as low computational efficiency or loss of resolution. To address these issues, we propose a multi-resolution planar region extraction strategy in this paper that balances the accuracy in boundaries and computational efficiency. Our method begins with a pointwise classification preprocessing module, which categorizes all sampled points according to their local geometric properties to facilitate multi-resolution segmentation. Subsequently, we arrange the categorized points using an octree, followed by an in-depth analysis of nodes to finish multi-resolution plane segmentation. The efficiency and robustness of the proposed approach are verified via synthetic and real-world experiments, demonstrating our method’s ability to generalize effectively across various uneven terrains while maintaining real-time performance, achieving frame rates exceeding 35 FPS. Copyright © 2023, The Authors. All rights reserved.

关键词： Computational efficiency

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Experimental study on the energy loss from flow and electrical of vanadium battery with constant pump frequency 2

Experimental study on the energy loss from flow and electric...

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2023 2nd International Conference on New Energy, Energy Storage and Power Engineering, NESP 2023

作者： Sun, Yanzhao Zou, Tao Li, Dianhong Li, Juntao School of Electrical Engineering and Automation Wuhan University Hubei Wuhan430072 China Big Pawer Electrical Technology Xiangyang Co. Ltd. Hubei Xiangyang441057 China Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and Science Hubei Xiangyang441053 China Hunan Vanadium Valley New Energy Technology Co. Ltd. Hunan Changsha410116 China

When the vanadium battery was running, pump frequency and current density were two frequently adjusted parameters. When the pump frequency was constant, the main flow-electrical parameter variation needs to be further studied. To this end, a 10 kW vanadium battery was built. When the current density was relatively high during the charge-discharge, the flow-electrical parameters of the cathode and anode including the temperature, flow resistance, turning voltage difference, capacity loss, energy loss and energy efficiency were studied. Besides, the compositions of capacity and energy were introduced, and the loss calculation scheme was proposed. Firstly, in flow analysis, the flow resistance was defined, which represents the flow state of the electrolyte. It was found that the flow resistance was nearly linear with the temperature. Secondly, in electric analysis, the turning voltage difference increased with the current density increasing. For the same current density, the total energy loss of charge was less than the discharge, and the energy loss of bypass was less than the internal resistance. With the current density increasing, the energy efficiency decreased. The research can be provided insight into the optimizing operation for the vanadium battery. © Published under licence by IOP Publishing Ltd.

关键词： Current density

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New design of smooth PSO-IPF navigator with kinematic constraints

arXiv

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arXiv 2024年

作者： Mohaghegh, Mahsa Jafarpourdavatgar, Hedieh Saeedinia, Samaneh Alsadat Auckland New Zealand Faculty of Design and Creative Technologies AUT Auckland New Zealand Control Engineering Department Amirkabir University Tehran Iran Complex System Laboratory Iran University of Science and Technology Tehran Iran

Robotic applications across industries demand advanced navigation for safe and smooth movement. Smooth path planning is crucial for mobile robots to ensure stable and efficient navigation, as it minimizes jerky movements and enhances overall performance Achieving this requires smooth collision-free paths. Partial Swarm Optimization (PSO) and Potential Field (PF) are notable path-planning techniques, however, they may struggle to produce smooth paths due to their inherent algorithms, potentially leading to suboptimal robot motion and increased energy consumption. In addition, while PSO efficiently explores solution spaces, it generates long paths and has limited global search. On the contrary, PF methods offer concise paths but struggle with distant targets or obstacles. To address this, we propose Smoothed Partial Swarm Optimization with Improved Potential Field (SPSO-IPF), combining both approaches and it is capable of generating a smooth and safe path. Our research demonstrates SPSO-IPF's superiority, proving its effectiveness in static and dynamic environments compared to a mere PSO or a mere PF approach. © 2024, CC BY.

关键词： Motion planning

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Interfacial area transport model for bubbly flow system in vertical rod bundle with spacer grids

Interfacial area transport model for bubbly flow system in v...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Liu, Hang Lai, Jianyong Li, Yi Zhang, Yulong Liu, Minghao Pan, Liangming Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Department of Nuclear Engineering Chongqing University Chongqing400044 China

ISBN: (纸本)9780791883785

In relation to the modeling of the one-dimensional interfacial area transport equation for an adiabatic bubbly flow in a vertical rod bundle, some existing models of sink and source terms were reviewed and evaluated. Based on the reviewed interaction mechanisms of bubbles and turbulent eddies, a new interfacial area transport model has been proposed. Two important impacts on bubble interaction have been taken into account in the new model: The effects of spacer grids with mixing vanes and the impacts of geometry structure. The spacer grids breakup large bubbles into small bubbles resulting in enhanced bubble random collision at the downstream of the spacer grids. Void transport is the main contribution between spacer grids. The new interfacial area transport model has been evaluated against the obtained experimental data in 17 bubbly flow conditions. The results indicate that the new model can predict the interfacial area concentration with the relative error of 19.9%. It is recognized that the proposed model is promising for predicting the interfacial area concentration for a bubbly flow in a rod bundle. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Nuclear engineering

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Broadband Wide-Angle Linear-to-Circular Polarization Converter Based on Metal Strips Loaded Metasurface

Broadband Wide-Angle Linear-to-Circular Polarization Convert...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Jingwen Wang Shasha Deng Weidong Chen Zhongxiang Zhang Chang Chen School of Information Science and Technology University of Science and Technology of China Hefei China Key Laboratory of simulation and design for Electronic information system Hefei Normal University Hefei China

A transmissive broadband wide-angle linear-to-circular polarization converter based on metal strips loaded metasurface is proposed in this paper. The converter is composed of three metallic layers separated by dielectric substrates and the metal strips printed on each layer keep orthogonal to each other. To further investigate the operating mechanism of the design, equivalent circuit models are presented. Moreover, the converter is verified to be effective in polarization conversion through the full-wave simulation. With the insertion loss less than 2 dB and 3 dB, the simulation 3-dB axial ratio (AR) bandwidth keeps 67% and 76%, respectively. Furthermore, at an increased incident angle of 40°, the device can still maintain an AR bandwidth over 47% at 2 dB insertion loss, which manifests the validity and rationality of the converter design.

关键词： Strips Computational modeling Metals Insertion loss Bandwidth Metasurfaces Broadband communication

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A Band Stop Decoupling Structure for Circularly Polarized Antennas With Different Intervals

A Band Stop Decoupling Structure for Circularly Polarized An...

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yuhang Ding Shasha Deng Weidong Chen Zhongxiang Zhang Chang Chen School of Information Science and Technology University of Science and Technology of China Hefei China Key Laboratory of simulation and design for Electronic information system Hefei Normal University Hefei China

In this paper, a novel band stop decoupling structure (BSDS) for circularly polarized microstrip antenna array with different intervals to realize mutual coupling reduction is proposed. The BSDS is composed of complementary split-rings resonator (CSRRs) and split-rings resonator (SRRs), where the CSRRs block TM waves by electric resonance and the SRRs block TE waves by magnetic resonance, respectively. The proposed design is verified by the simulation and the results indicate that the isolation enhancement more than 35 dB can be obtained at the center frequency of 3.4 GHz when the center spacing is 0.37 $\lambda$0. Futhermore, when the center spacing reduces to 0.26 $\lambda$0, the mutual coupling remains below 25 dB. Besides, the BSDS can improve the radiation pattern offset without affecting the gain and the backward radiation of antennas.

关键词： Mutual coupling Microstrip antenna arrays Surface waves Simulation Magnetic resonance Microstrip antennas Scattering parameters

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Multiple choices of reactor core nuclear design for ACP100's application in different scenarios

Multiple choices of reactor core nuclear design for ACP100's...

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2020 International Conference on Physics of reactors: Transition to a Scalable Nuclear Future, PHYSOR 2020

作者： Wang, Liangzi Ju, Haitao Li, Qing Qin, Dong Wang, Lianjie Yu, Yingrui Ning, Zhonghao Wang, Chenlin Guo, Rui Wang, Shuai Zhang, Bin Xiang, Hongzhi Lou, Lei Sun, Wei Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China NO. 328 Section 1 Changshun Ave Shuangliu District Sichuan Chengdu China

ISBN: (纸本)9781713827245

ACP100 NPP designed by CNNC (China National Nuclear Corporation) is a 125MWe, multi-purpose small modular reactor based on pressurized water reactor technology;it adopts the integrated reactor technology. Different application scenarios bring up different design requirements: some require high compactness, but others care more about a longer cycle length, and some may require a fully mature and conservative design;thus, multiple design choices need to be proposed. Also, the same and most important thing cared by all users is that, the design needs to be validated to satisfy the current nuclear safety standards, and lower cost would be always preferred. Core nuclear design is a key part of the whole NPP design. Basically, nuclear design target of ACP100 is to achieve a reasonable good balance during longer cycle length, larger discharge exposure for fuel assemblies, and maximally using the mature technologies, and of course, with sufficient reactivity control ability for safety assurance. Aiming at satisfying all these different needs maximally, a strategy of supplying multiple nuclear design choices is proposed for ACP100: choice 1. Boron-free plan, this is a compact design with no need for chemistry and volume system, no need for da ily boron adjustment and relative waste storage;choice 2. Boron and rod co-controlled plan, this is similar with large commercial PWRs, with a lower power peak factor and suitable for broad location sites. Both choices load 57 units of the same type fuel assemblies CF3S (with height reduced from CF3 fuel assemblies) per cycle, and both adopt partial reload and shuffle fuel management strategy to achieve larger discharge exposure. Gd is loaded in the fuel rods in both choices to help control reactivity. Choice 1 loads much more control rod clusters than choice 2, and of course, reactivity adjustment and compensation during operation is totally different between them. Using suitable and reliable software to simulate t he core, through lar

关键词： Boron

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RMC/ANSYS Multi-physics coupling solutions for heat pipe cooled reactors analyses

RMC/ANSYS Multi-physics coupling solutions for heat pipe coo...

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2020 International Conference on Physics of reactors: Transition to a Scalable Nuclear Future, PHYSOR 2020

作者： Ma, Yugao Liu, Minyun Chen, Erhui Xie, Biheng Chai, Xiaoming Huang, Shanfang Wang, Kan Yu, Hongxing Department of Engineering Physics Tsinghua University Beijing100084 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9781713827245

The heat pipe cooled reactor is a solid-state reactor using heat pipes to passively transfer heat generated from the reactor, which is a potential and near-term space nuclear power system. This paper introduces the coupling scheme between the continuous energy reactor Monte Carlo (RMC) code and the finite element method commercial software ANSYS. Monte Carlo method has the advantages of flexible geometry modeling and continuous-energy nuclear cross sections. ANSYS Parametric design Language (APDL) is used to determine the detailed temperature distributions and geometric deformation. The on-the-fly temperature treatment of cross sections was adopted in RMC code to solve the memory problems and to speed up simulations. This paper proposed a geometric updating strategy and reactivity feedback methods for the geometric deformation of the solid-state core. The neutronic and thermal-mechanical coupling platform is developed to analyze and further to optimize the heat pipe cooled reactor design. The present coupling codes analyze a 2D central cross-section model for MEGAPOWER heat pipe cooled reactor. The thermal-mechanical feedback reveals that the solid-state reactor has a negative reactivity feedback (~1.5 pcm/K) while it has a deterioration in heat transfer due to the expansion. © The Authors, published by EDP sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://***/licenses/by/4.0/).

关键词： Finite element method

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design of Metamaterial Absorber at X Band Using BP Neural Network

Design of Metamaterial Absorber at X Band Using BP Neural Ne...

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IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP)

作者： Xianliang Zeng Yin Yu Yiting Shuai Weijun Wu Li Tao Science and Technology on Electromagnetic Compatibility Laboratory China Ship Development and Design Center Combat System Develop Department China Ship Development and Design Center

The absorption performance of metamaterial absorber is determined by the configuration parameters of the metallic pattern, the thickness and dielectric constants of the substrate. Conventional parameter sweep method and adjoint- based optimization are time consuming. In this work, a metamaterial absorber at X band is designed by using the BP neural network. In order to determine the geometry parameters for realizing the perfect absorption performance, 81 different simulation results are trained with the BP neural network. The designed structure can obtain the low reflection of -14.09dB at 10GHz. Compared to the full wave simulation, the calculation time with BP neural network is much shorter, which can be widely applied in other artificial electromagnetic structure based on metamaterials.

关键词： Geometry Radio frequency Absorption Simulation Neural networks Predictive models Metamaterials

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Addition of Niobium in Fe-13cr-4.5al-2mo Alloy Used as Atf Cladding: Effect on High Temperature Water Corrosion and In-Situ Electrochemistry

SSRN

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SSRN 2022年

作者： Liao, Jingjing Wang, Hui Wu, Jun Zhang, Wei Xu, Fei Sun, Hongying An, Xuguang Qiu, Shaoyu Chengdu University China Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of China Sichuan Chengdu610213 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu610213 China School of Mechanical Engineering Anyang Institute of Technology Henan Anyang455002 China Interdisciplinary Materials Research Center Institute for Advanced Study Chengdu University Sichuan Chengdu610106 China

Niobium addition in candidate accident tolerant fuel (ATF) cladding FeCrAl alloy has received much attention, but its effect on high temperature water corrosion behavior has not been revealed. Four alloys with different Nb content (0wt%, 0.5wt%, 1.0wt% and 1.5wt%) based on Fe-13Cr-4.5Al-2Mo model alloy were designed, and the corrosion behavior was investigated by in-situ electrochemistry and microscopy. The in-situ electrochemistry analyses were carried out in 360 。C/19.0MPa lithiated and borated water connected with a loop system to monitor the water chemistry. Detailed studies on the oxide film formed after exposure for 85 days were conducted by focused ion bombarding and transmission electron microscopy. FeCrAl alloys have satisfactory corrosion resistance because of small corrosion currents and thin oxide films. Only monolayer multicrystal spinel oxide forms on alloy surface. Slight Nb addition (0.5% and 1.0wt%) benefits the corrosion resistance due to relatively large impedance of oxide and delayed oxidation of Fe2 Nb particles. Porosities with Fe depletion are spotted in oxide and especially severe in 1.5wt%-Nb alloy. Cathodic Tafel kinetics and corrosion mechanisms of FeCrAl are further discussed. © 2022, The Authors. All rights reserved.

关键词： Oxide films

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