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Influences of the ambient humidity and temperature on the material removal and wear behaviors on the soft-brittle KDP optics lithographed by the AFM probes

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Wear 2025年

作者： Chen, Guang Cheng, Jian Zhao, Linjie Chen, Mingjun Ding, Wenyu Lei, Hongqin Liu, Qi State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou450000 China Centre for Precision Manufacturing DMEM University of Strathclyde GlasgowG1 1XJ United Kingdom

KDP (K2HPO4) crystals possess excellent nonlinear electro-optical properties and are often employed as Pockels cells and frequency converters. Ink-free DPN (IF-DPN) provides a promising method to lithograph surface nano-patterns in KDP optics to improve their laser damage resistances. However, material removal and wear behaviors are greatly affected by humidity and temperature. In this work, theoretical analyses at atomic- and electronic-scales are performed based on molecular dynamics and ab initio to study lithography behaviors (indentation and scratching) for IF-DPN. Lithography experiments with different humidity and temperatures are also executed on KDP substrate, which align well with theoretical results. During indentation processes, surface materials are squeezed into substrate, leading to deep subsurface damages and significant material recoveries. While the scratching processes would cause intense surface material stripping, and sharp-edge of AFM probe facilitates this process. Numerous K-related chemical structure defects would emerge during the lithography processes, which is the predisposition of microstructure change inside KDP crystal. The binding processes of AFM probe, water, and KDP crystal are spontaneous exothermic reactions. Bonding reactions of Si-O, Si-H, and O-H covalent bonds would expedite the wear of AFM probe and KDP crystal. The humidity affects lithography behaviors mainly through chemical dissolution actions, reducing surface integrity and structural strength of KDP crystal and facilitating material stripping. The high humidity would intensify the hydroxylation reaction occurring on AFM probe and KDP crystal surfaces, enhancing their hydrophilicity. The high temperature would result in a reduction of the condensed water meniscus and adsorbed water film, weakening chemical actions of IF-DPN. But it is beneficial for the penetration of AFM probe into KDP crystal surface, material stripping, and minimization of subsurface damages. The hig

关键词： Molecular dynamics

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An Evolutionary Game based Secure Clustering Protocol with Fuzzy Trust Evaluation and Outlier Detection for Wireless Sensor Networks

arXiv

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arXiv 2022年

作者： Yang, Liu Lu, Yinzhi Yang, Simon X. Zhong, Yuanchang Guo, Tan Liang, Zhifang The School of Communication and Information Engineering Chongqing University of Posts and Telecommunications Chongqing China The Advanced Robotics and Intelligent Systems Laboratory School of Engineering University of Guelph GuelphONN1G2W1 Canada The State Key Laboratory of Power Transmission Equipment & System Security and New Technology School of Electrical Engineering Chongqing University Chongqing400044 China

Trustworthy and reliable data delivery is a challenging task in Wireless Sensor Networks (WSNs) due to unique characteristics and constraints. To acquire secured data delivery and address the conflict between security and energy, in this paper we present an evolutionary game based secure clustering protocol with fuzzy trust evaluation and outlier detection for WSNs. Firstly, a fuzzy trust evaluation method is presented to transform the transmission evidences into trust values while effectively alleviating the trust uncertainty. And then, a K-Means based outlier detection scheme is proposed to further analyze plenty of trust values obtained via fuzzy trust evaluation or trust recommendation. It can discover the commonalities and differences among sensor nodes while improving the accuracy of outlier detection. Finally, we present an evolutionary game based secure clustering protocol to achieve a trade-off between security assurance and energy saving for sensor nodes when electing for the cluster heads. A sensor node which failed to be the cluster head can securely choose its own head by isolating the suspicious nodes. Simulation results verify that our secure clustering protocol can effectively defend the network against the attacks from internal selfish or compromised nodes. Correspondingly, the timely data transfer rate can be improved significantly. © 2022, CC BY.

关键词： Sensor nodes

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Long-term Dependency for 3D Reconstruction of Freehand Ultrasound Without External Tracker

arXiv

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arXiv 2023年

作者： Li, Qi Shen, Ziyi Li, Qian Barratt, Dean C. Dowrick, Thomas Clarkson, Matthew J. Vercauteren, Tom Hu, Yipeng The UCL Centre for Medical Image Computing The Wellcome/EPSRC Centre for Interventional and Surgical Sciences Department of Medical Physics and Biomedical Engineering University College London LondonWC1E 6BT United Kingdom State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China School of Biomedical Engineering & Imaging Sciences King’s College London LondonWC2R 2LS United Kingdom

Objective: Reconstructing freehand ultrasound in 3D without any external tracker has been a longstanding challenge in ultrasound-assisted procedures. We aim to define new ways of parameterising long-term dependencies, and evaluate the performance. Methods: First, long-term dependency is encoded by transformation positions within a frame sequence. This is achieved by combining a sequence model with a multi-transformation prediction. Second, two dependency factors are proposed, anatomical image content and scanning protocol, for contributing towards accurate reconstruction. Each factor is quantified experimentally by reducing respective training variances. Results: 1) The added long-term dependency up to 400 frames at 20 frames per second (fps) indeed improved reconstruction, with an up to 82.4% lowered accumulated error, compared with the baseline performance. The improvement was found to be dependent on sequence length, transformation interval and scanning protocol and, unexpectedly, not on the use of recurrent networks with long-short term modules;2) Decreasing either anatomical or protocol variance in training led to poorer reconstruction accuracy. Interestingly, greater performance was gained from representative protocol patterns, than from representative anatomical features. Conclusion: The proposed algorithm uses hyperparameter tuning to effectively utilise long-term dependency. The proposed dependency factors are of practical significance in collecting diverse training data, regulating scanning protocols and developing efficient networks. Significance: The proposed new methodology with publicly available volunteer data and code1 for parametersing the long-term dependency, experimentally shown to be valid sources of performance improvement, which could potentially lead to better model development and practical optimisation of the reconstruction application. © 2023, CC BY.

关键词： Ultrasonics

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Nonequilibrium Effects on Rapid Directional Solidification Microstructures During Additive Manufacturing: A Quantitative Phase Field Study

SSRN

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SSRN 2024年

作者： Li, Leiji Xiao, Fei Li, Zhu He, Shiyu Liu, Yang Cai, Xiaorong Hou, Ruihang Zhou, Ying Zuo, Shungui Zhang, Chongfeng Gao, Jinzhong Shen, Xiaopeng Zhu, Tianchi Gu, Yijia Jin, Xuejun State Key Lab of Metal Matrix Composite School of Materials Science and Engineering Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai200240 China Institute of Medical Robotics Shanghai Jiao Tong University Shanghai200240 China National Key Laboratory of Aerospace Mechanism Aerospace System Engineering Shanghai 3805 Jin Du Road Shanghai201108 China Department of Materials Science and Engineering Missouri University of Science and Technology RollaMO65409 United States National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy School of Materials Science and Engineering Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai200240 China Department of Materials Science and Engineering Graduate School of Engineering Osaka University 2-1 Yamada-oka Osaka Suita565-0871 Japan Shanghai Key Laboratory of Materials Laser Processing and Modification China

Fusion-based metal additive manufacturing (AM) is a technology that builds objects layer by layer, with rapid solidification referring to the quick transition of material from liquid to solid. During this process, solute trapping, a nonequilibrium effect characterized by velocity-dependent partition coefficient, significantly influences microstructure kinetics, morphology, and phase formation. This study utilizes the latest quantitative phase field (PF) model to systematically investigate the solute trapping, solute drag, and their effects on pattern formation during rapid solidification at velocities relevant to AM, in both one and two dimensions. Under different temperature gradients and pulling velocities, we observed that the growth mode transits from planar to cellular to dendritic, then back to cellular, and finally to planar, which is consistent with classic solidification theory. A solidification microstructure selection map is constructed based on PF simulations. Furthermore, we compared primary dendritic/cell spacing calculated by the PF model with theoretical models. The simulated morphologies and arm spacing showed good agreement with experimental observations for Al-4Si and Ti-20Nb alloys during rapid solidification. These results demonstrate the potential of the PF model for predicting and controlling microstructure formation under rapid solidification conditions in the melt pool of AM processes. © 2024, The Authors. All rights reserved.

关键词： Morphology

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Optimal allocation of distributed generation in radial distribution network for voltage stability improvement and power loss minimization

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AIP Conference Proceedings 2023年第1期2612卷

作者： M. Khasanov S. Kamel K. Xie A. Kurbanov A. Jumanov U. Jalilov 1State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical Engineering Chongqing University Chongqing China 2Department of Electrical Engineering Faculty of Engineering Aswan University Aswan Egypt 3Department of Energy Faculty of Energy and radio electronics Jizzakh Polytechnic Institute Jizzakh Uzbekistan

Voltage instability and power loss are significant problems in distribution networks (DN). However, these problems are usually mitigated by the optimal integration of distributed generation (DG) units in the DN. In this regard, the optimal location and size of the DGs are crucial. Otherwise, network performance will deteriorate. This study is conducted to placemat and sizing the DGs in the radial DN. Mayfly Algorithm (MA) is used to determine the optimal placement and size of the DGs to minimize power loss, increases voltage stability in radial DN. The simulation results showed a reduction in the percentage of power loss is 69.14% for three PV-type DG unit integration. The corresponding percentage of power loss reduction is 98.09 % for three WT-type DG units by installing DG units to the test network. Similarly, the minimum bus voltage stability improves to 0.959 per unit for three PV type DG unit integration. The VSI after DG allocation increases to 0.989 per unit for three WT type DG units by optimal installing DG units. Comparative studies have been conducted, and the results have shown the effectiveness of the proposed method in reducing the power loss and improving the voltage stability of the DN. The proposed algorithm is evaluated in the IEEE-69 bus radial DN using MATLAB.

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Learning-Based Gravity Estimation for Robot Manipulator Using KRR and SVR

Learning-Based Gravity Estimation for Robot Manipulator Usin...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Chenglong Yu Zhiqi Li Hong Liu Alan.F. Lynch State Key Laboratory of Robotics and System Harbin Institute of Technology China Applied Nonlinear Controls Lab University of Alberta Edmonton T6G 1H9 Canada

ISBN: (数字)9781728167947

ISBN: (纸本)9781728167954

In this paper, a learning-based method for estimating the parameters of the gravity term of a manipulator with the kernel trick approach is presented. This method extracts the mapping equation from the analytical form of the dynamic equation. Based only on the configuration and sampling data of the robotic arm, Kernel ridge regression (KRR) and Support vector regression (SVR) algorithms are introduced to estimate the position parameters and provide a comparison between different learning regression techniques. The novelty of this work is the time-efficient estimation of robot gravity through randomly located joint sampling data using the kernel trick. The optimal solution to the optimal trade-off curve is proposed and discussed. Theoretical analysis shows that the joint angle and driving torque can be used to estimate the relationship between the center of gravity of the manipulator links and the mass of the connecting rod to obtain an accurate dynamic gravity model.

关键词： Gravity Mathematical model Manipulator dynamics Torque Jacobian matrices

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Localization and Surface Characterization by Zhurong Mars Rover at Utopia Planitia

Research Square

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Research Square 2021年

作者： Ding, Liang Zhou, Ruyi Yu, Tianyi Gao, Haibo Yang, Huaiguang Li, Jian Yuan, Ye Liu, Chuankai Wang, Jia Zhao, Yuyan Wang, Zhengyin Wang, Xiyu Bao, Gang Deng, Zongquan Huang, Lan Li, Nan Cui, Xiaofeng He, Ximing Jia, Yang Yuan, Baofeng Liu, Guangjun Zhang, Hui Zhao, Rui Zhang, Zuoyu Cheng, Ziqing Wu, Fan Xu, Qian Lu, Hao Richter, Lutz Liu, Zhen Niu, Fuliang Qi, Huanan Li, Shu Feng, Wenhao Yang, Chaojie Chen, Baichao Dang, Zhaolong Zhang, Mingming Li, Lichun Wang, Xiaoxue Huang, Zhao Zhang, Jitao Xing, Hongjun Wang, Guanyu Niu, Lizhou Xu, Peng Wan, Wenhui Di, Kaichang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China Beijing Aerospace Control Center Beijing100094 China Center for Lunar and Planetary Sciences Institute of Geochemistry Chinese Academy of Science Guiyang550081 China CAS Center for Excellence in Comparative Planetology Hefei230026 China University of Chinese Academy of Sciences Beijing100049 China Beijing Institute of Spacecraft System Engineering Beijing100094 China Department of Aerospace Engineering Ryerson University TorontoONM5B 2K3 Canada Hauptstrasse 1e Eching Germany State Key Laboratory of Remote Sensing Science Aerospace Information Research Institute Chinese Academy of Sciences Beijing100101 China

China’s first Mars rover, Zhurong, has successfully touched down on the southern Utopia Planitia of Mars at 109.925° E, 25.066° N, and since performed cooperative multiscale investigations with the Tianwen-1 orbiter. Here we present primary localization and surface characterization results based on complementary data of the first 60 sols. The Zhurong rover has traversed 450.9 m southwards over a flat surface with mild wheel slippage (less than 0.2 in slip ratio). The encountered crescent-shaped sand dune indicates a NE-SW local wind direction, consistent with larger-range remote-sensing observations. Soil parameter analysis based on terramechanics indicates that the topsoil has high bearing strength and cohesion, and its equivalent stiffness and internal friction angle are ~1390-5872 kPa∙m-n and ~21°-34° respectively. Rocks observed strewn with dense pits, or showing layered and flaky structures, are presumed to be involved in physical weathering like severe wind erosion and potential chemical weathering processes. These preliminary observations suggest great potential of in-situ investigations by the scientific payload suite of the Zhurong rover in obtaining new clues of the region’s aeolian and aqueous history. Cooperative investigations using the related payloads on both the rover and the obiter could peek into the habitability evolution of the northern lowlands on Mars. © 2021, CC BY.

关键词： Sols

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Optimal radial distribution network reconfiguration to minimize power loss by using mayfly algorithm

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AIP Conference Proceedings 2023年第1期2612卷

作者： M. Khasanov K. Xie S. Kamel J. Abdubannaev A. Kurbanov U. Jalilov 1State Key Laboratory of Power Transmission Equipment and System Security and New Technology School of Electrical Engineering Chongqing University Chongqing China 2Department of Electrical Engineering Faculty of Engineering Aswan University Aswan Egypt 3School of Electrical & Electronic Engineering North China Electric Power University Beijing China 4Department of Energy Faculty of Energy and radio electronics Jizzakh Polytechnic Institute Jizzakh Uzbekistan

With industry development, suburbanization, and population growth, the load demand is constantly increasing year by year. Excessive load demand has greatly strained the distribution network (DN), resulting in increased power losses due to the high-power flow. Therefore, it becomes very important to minimize power losses at the DN to maximize the efficiency of the distribution companies. Network reconfiguration is one of the effective methods used by distribution companies to minimize losses in the DN. This paper proposes Mayfly Algorithm (MA) to solve network reconfiguration problems and minimize the DN's power loss. MA is inspired by the social behavior of the mayflies, especially their mating process. IEEE-33 bus DN has been used to demonstrate the effectiveness of the proposed method. The obtained simulation results compared with other methods in the literature and comparison showed that the proposed MA provides better quality solutions than other methods.

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Multi-class classification method for strip steel surface defects based on support vector machine with adjustable hyper-sphere

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Journal of Iron and Steel Research International 2018年第7期25卷 706-716页

作者： Mao-xiang Chu Xiao-ping Liu Rong-fen Gong Jie Zhao School of Electronic and Information Engineering University of Science and Technology Liaoning Anshan 114051 Liaoning China Department of Electrical Engineering Lakehead University Thunder Bay P7B 5E1 ON Canada State Key Laboratory of Robotics and System (HIT) Harbin 150001 Heilongjiang China

Focusing on strip steel surface defects classification, a novel support vector machine with adjustable hyper-sphere （AHSVM） is formulated. Meanwhile, a new multi-class classification method is proposed. Originated from support vector data description, AHSVM adopts hyper-sphere to solve classification problem. AHSVM can obey two principles： the margin maximization and inner-class dispersion minimization. Moreover, the hyper-sphere of AHSVM is adjustable, which makes the final classification hyper-sphere optimal for training dataset. On the other hand, AHSVM is combined with binary tree to solve multi-class classification for steel surface defects. A scheme of samples pruning in mapped feature space is provided, which can reduce the number of training samples under the premise of classification accuracy, resulting in the improvements of classification speed. Finally, some testing experiments are done for eight types of strip steel surface defects. Experimental results show that multi-class AHSVM classifier exhibits satisfactory results in classification accuracy and efficiency.

关键词： Strip steel surface defect Multi-class classification Supporting vector machine Adjustable hyper-sphere

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Experiments on the vibration of particles levitating in a standing wave acoustic field

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Proceedings of Meetings on Acoustics 2019年第1期38卷

作者： Huijuan Dong Yi Wang Yingzi Guan Guanyu Mu Jie Zhao 1State Key Laboratory of Robotics and System Harbin Institude of Technology Harbin Heilongjiang 150001 CHINA dhj@*** wangyiabc@*** guanyz@*** mu-guanyu@*** jzhao@***

Standing wave acoustic levitation and transmission technique has been widely used in many research areas. However, the vibration of particles in an acoustic field restricts their applications. In this work, a kind of mechanism is developed by the authors, in which not only a harmonic linear actuator but also position feedback are used to precisely adjust the distance between the radiator and the reflector with micrometric accuracy. And video computing software is applied to track the motion of the particle. The influence of the factors on the frequencies of the particle both in vertical and horizontal were detailed. Besides, the acceleration field was calculated, which is in good agreement with the model of spring oscillator of an acoustic field.

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