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Construction of Fe/Ag galvanic couple by mechanochemical in-situ reduced Ag to accelerate the degradation of Fe-based implant

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Science China(Technological Sciences) 2023年第10期66卷 2824-2836页

作者： YANG WenJing SONG Hao ZHAO ZhengYu SHUAI CiJun PAN Hao Institute of Bioadditive Manufacturing Jiangxi University of Science and TechnologyNanchang 330013China Shenzhen Institute of Information Technology School of Sino-German RoboticsShenzhen 518172China State Key Laboratory of Precision Manufacturing for Extreme Service Performance College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China Department of Periodontics&Oral Mucosal Section Xiangya Stomatological HospitalCentral South UniversityChangsha 410013China

Orthopedic applications of Fe have been hindered by the insufficient degradation *** with noble elements(such as Ag,Au,and Pt)to generate galvanic couples is a feasible ***,the direct preparation of homogenous alloys by mechanical alloying or metallurgy is difficult because of the differences in strength,density,and *** this study,Ag_(2)O was selected as the precursor phase for incorporation into Fe to achieve a homogeneous distribution of Ag,which was then reduced in situ to Ag via a mechanochemical reduction reaction during mechanical *** composite powders were printed as implants by selective laser melting,where a fast cooling rate contributed to the retention of the phase distribution of the obtained *** electrochemical tests showed that the Fe-Ag_(2)O implant had a high corrosion current density(21.88±0.12μA/cm^(2))and instantaneous corrosion rate(0.23±0.05 mm/year).Moreover,the implant exhibited a faster degradation rate(0.22 mm/year)than Fe(0.15 mm/year)and Fe-Ag(0.21 mm/year)after immersion for 28 *** acceleration mechanism of the implant could be attributed to the uniformly distributed Ag particles triggering many galvanic couples with the Fe grains,which was confirmed by the observation of the corrosion *** addition,the composite implants exhibited good biocompatibility and antibacterial properties.

关键词： biodegradable implant mechanochemical reduction uniform dispersion galvanic corrosion

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Quantifying foliar trait variation and covariation in sun and shade leaves using leaf spectroscopy in eastern North America

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Forest Ecosystems 2024年第5期11卷 728-742页

作者： Zhihui Wang Philip A.Townsend Eric L.Kruger Anna K.Schweiger Guangdong Provincial Key Laboratory of Remote Sensing and Geographical Information System Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of SciencesGuangzhou510070China Department of Forest and Wildlife Ecology University of Wisconsin-Madison1630 Linden DriveMadisonWI53706USA Department of Land Resources and Environmental Sciences Montana State University334 Leon Johnson HallBozemanMT59717USA

Characterizing foliar trait variation in sun and shade leaves can provide insights into inter-and intra-species resource use strategies and plant response to environmental ***,datasets with records of multiple foliar traits from the same individual and including shade leaves are sparse,which limits our ability to investigate trait-trait,trait-environment relationships and trait coordination in both sun and shade *** presented a comprehensive dataset of 15 foliar traits from sun and shade leaves sampled with leaf spectroscopy,including 424 individuals of 110 plant species from 19 sites across eastern North *** investigated trait variation,covariation,scaling relationships with leaf mass,and the effects of environment,canopy position,and taxonomy on trait ***,sun leaves had higher leaf mass per area,nonstructural carbohydrates and total phenolics,lower mass-based chlorophyll a+b,carotenoids,phosphorus,and potassium,but exhibited species-specific *** between sun and shade leaf traits,and trait-environment relationships were overall consistent across *** main dimensions of foliar trait variation in seed plants were revealed including leaf economics traits,photosynthetic pigments,defense,and structural *** and canopy position collectively explained most of the foliar trait *** study highlights the importance of including intra-individual and intra-specific trait variation to improve our understanding of ecosystem *** findings have implications for efficient field sampling,and trait mapping with remote sensing.

关键词： Foliar traits Leaf trait variation Trait-environment covariation Shade leaves NEON Leaf spectroscopy

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Intra-Day Rolling Optimal Strategy Considering Whole Dispatch Process and Multi-Type Adjustable Measures 7

Intra-Day Rolling Optimal Strategy Considering Whole Dispatc...

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7th International Conference on Power and Energy Applications, ICPEA 2024

作者： Li, Wenzhong Zhang, Duanhong Tian, Xichen Lv, Yan Xu, Zhengqi Liang, Jingfeng State Grid Fujian Electric Power Dispatching and Control Center State Grid Fujian Electric Power Company Fuzhou China China Electric Power Research Institute Beijing Key Laboratory of Research and System Evaluation of Power Dispatching Automation Technology Beijing China

ISBN: (纸本)9798350356113

The current electric power system practices hierarchical and zonal administration to facilitate more effective monitoring of grid safety and event management. With an escalating integration of new energy sources on the generation side, the intrinsically variable nature of these resources introduces substantial uncertainties into grid operations. Meanwhile, on the demand side, load profiles are diversifying further, significantly influenced by weather conditions, market price signals, or incentive schemes, thereby adding another layer of unpredictability. Against this context, this paper proposes an intra-day rolling optimal strategy considering whole dispatch process and multi-type adjustable measures. By synthesizing regulating resources from both the source and load sides, it undertakes a series of intra-day rolling optimization decisions across the entire dispatch workflow. This strategy aims to harmonize and optimize the allocation of various resources, thereby ensuring the secure and stable functioning of the electrical grid amidst the complexities introduced by the integration of intermittent renewables and the dynamics of diversified loads. © 2024 IEEE.

关键词： Electric load dispatching

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Tsun: A Traversability-Based Safety-Ensured Uneven Terrain Navigation system

SSRN

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SSRN 2024年

作者： Wang, Han Wang, Gongcheng Zhu, Hongbiao Du, Chengjin Bai, Hua Ding, Pengchao Xu, Wenda Du, Zhijiang Wang, Weidong The State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China Istituto Italiano di Tecnologia The BioRobotics Institute Scuola Superiore Sant’Anna Genova16163 Italy

The application of autonomous navigation in mobile robots has seen notable success in indoor, structured 2D environments. However, applying this technology to outdoor, 3D unstructured environments — especially on uneven terrains, presents significant challenges. To address this, we propose a navigation framework for uneven terrain based on continuous traversability analysis. Our methodology unfolds in three stages: First, Bayesian generalized kernel inference is employed to estimate attributes of the unobserved point cloud, enabling the computation of continuous terrain traversability values by using dispersed point cloud data. Second, an improved A* (TRA-A*) algorithm is proposed for global path determination. In the final stage, nonlinear model predictive control (NMPC) is utilized for path following. This involves integrating the traversable exponents and uncertainty into the cost function, resulting in a safety-focused motion planning algorithm that encourages the navigation stability of the robot. The effectiveness of this method was verified through simulation and actual scene experiments. This algorithm improves the robot's navigation success rate by 8% while sacrificing a small amount of 9.83% of the path length in the actual environment, preventing the robot from tipping over or getting stuck in rough terrain, and improving the stationarity of the robot during driving. It reduces the cost of the terrain the robot travels on by 42.6%, reduces the robot's longitudinal acceleration fluctuation and lateral angular velocity fluctuation by 28.52% and 28.9% respectively, and improves the robot's driving stability. © 2024, The Authors. All rights reserved.

关键词： Cost functions

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An Efficient Inverse Kinematic Method for SSRMS-type Manipulator with Conformal Geometric Algebra

An Efficient Inverse Kinematic Method for SSRMS-type Manipul...

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

作者： Jingdong Zhao Jiayu Zhang Liangliang Zhao Zhonglai Tian Zirui Wang Wei Jiang Hong Liu School of Mechatronics Engineering State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin Heilongjiang Province China

ISBN: (数字)9798350355369

ISBN: (纸本)9798350355376

SSRMS-type Manipulator is a typical type of space manipulator featuring 7-degree-of-freedom offset configuration with redundancy characteristic. It is challenging to solve inverse kinematics in high efficiency, make the upmost of redundancy characteristic, and select optimal redundant parameter. This paper proposes an analytical inverse kinematic method, named three-continuous-parallel-Link Direction Vector Parameterization (LDVP), in the theory of Conformal Geometric Algebra. This method employs the direction vector of the axis of parallel Joint 3, Joint 4, and Joint 5 as the parameter, and selects the optimal parameter according to context plan-points in a given trajectory. The process of solving inverse kinematics is divided into two steps, including solving joint positions and joint variables. The average solution time of forward and inverse kinematics is 9.79 us and 0.25 ms respectively. The continuous path tracking experiment verifies that all seven joints changing to pursue the optimal configuration, which makes full use of redundancy characteristic.

关键词： Mechatronics Algebra Termination of employment Kinematics Manipulators Vectors Orbits

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Noise Mask Network-based Feature Learning of Vibration Signals for Machinery Fault Diagnosis under Multiple Non-ideal Conditions

Noise Mask Network-based Feature Learning of Vibration Signa...

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2024 IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 2024

作者： Miao, M.Q. Yu, J.B. School of Mechanical Engineering Tongji University Shanghai201804 China State Key Laboratory of Large Electric Drive System and Equipment Technology Tianshui Electric Drive Research Institute Group Co. LTD Tianshui741020 China

ISBN: (纸本)9798350386097

Although deep learning techniques have been successfully applied in machinery fault diagnosis, the key problems of feature learning under multiple non-ideal conditions have not been well solved, such as noise interference, limited labeled data, and class imbalance. In this study, noise mask network (NMNet) is developed for feature learning and machinery fault diagnosis under multiple non-ideal conditions. Firstly, a temporal masking block (TMB) is proposed for imbalanced data enhancement. Secondly, a temporal self-supervised learning framework (TSLF) is developed for noise filtering and solving the problem of limited annotation data simultaneously. In addition, an asymmetric multi-scale autoencoder (AMSA) is constructed for deep feature learning and signal reconstruction. The experiment results on rotor testbed demonstrate the effectiveness of NMNet for machinery fault recognition with several non-ideal conditions. © 2024 IEEE.

关键词： Self-supervised learning

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Coherence analysis of laser pulses based on an external cavity circulation 1

Coherence analysis of laser pulses based on an external cavi...

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1st International Conference on Spatial Atmospheric Marine Environmental Optics, SAME 2023

作者： Xu, He Sun, Difeng Li, Jianbing National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System College of Electronic Science and Technology Hunan Changsha410073 China Northwest Institute of Nuclear Technology Shaanxi Xi’an710024 China

ISBN: (纸本)9781510666337

By constructing an external circulating cavity to provide sufficient delay that equals a multiple of pulse repetition time, a method with a fixed experimental configuration is proposed to measure the coherence length of both single-frequency and microwave-modulated optical pulses. This method can accurately determine the number of coherent pulses as well as distinguish the coherence states: complete coherence, partial coherence and complete incoherence. In addition, all desired coherence phenomena are obtained by one-time measurement, avoiding other operations like frequent fiber-cutting or devices-reconnection in previous methods. Simulation results show that the coherence length of the dual-frequency laser is periodically extended by the reciprocal of the frequency difference, and the random jitter of pulse propagation time would result in obvious measurement errors via perturbing coherence status. © 2023 SPIE.

关键词： Random errors

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Electrical and optical properties of three BaTiO3 crystal phases by the first-principles study 6

Electrical and optical properties of three BaTiO3 crystal ph...

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6th International Conference on Optoelectronic Science and Materials, ICOSM 2024

作者： Ma, Xinguo Liu, Zhiwen Guo, Youyou Ren, Yijing State Key Laboratory of Advanced Technology for Float Glass Bengbu Glass Industrial Design and Research Institute Bengbu233030 China School of Science Hubei University of Technology Wuhan430068 China Hubei Engineering Technology Research Center of Energy Photoelectric Device and System Hubei University of Technology Wuhan430068 China

ISBN: (数字)9781510686823

ISBN: (纸本)9781510686816

The study on the properties of barium carbonate in different crystal systems is play an important role for the evolution of electronic products requiring miniaturization and high performance. Here, the electrical and optical properties of BaTiO3 crystal structures with three space groups (Pm 3 m, P4mm, and P4/mmm) were systematically studied using the first-principles method. The structural are confirmed to be stable by the Born criterion The evolution energy band structures under HSE06 functional were more consistent with other theoretical and experimental results compared to the PBE functional. The band gaps of BaTiO3 for Pm 3 m, P4mm, and P4/mmm space groups up to 3.42, 3.24, and 3.26 eV and exhibit indirect semiconductor behavior. The optical parameters show that the light absorption rate and loss function of all three BaTiO3 were almost zero in the lower energy range. However, the tetragonal phase BaTiO3 with P4/mmm space group has a lower light reflection rate and higher light refractive index compared to the tetragonal phase BaTiO3 with P4/mmm and the cubic phase BaTiO3 with Pm 3 m space group, indicating its potential application value in electro-optic modulation. © 2024 SPIE.

关键词： Refractive index

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Visual Servo Stabilization of Nonholonomic Mobile Robot Based on Epipolar Geometry and 1D Trifocal Tensor

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Chinese Journal of Electronics 2023年第4期22卷 729-734页

作者： CAO Zhengcai YIN Longjie FU Yili ZHANG Jie College of Information Science and Technology Beijing University of Chemical Technology Beijing China The State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin China

In this paper, a visual servo stabilization approach consisting in a dynamic switching control law for a nonholonomic mobile robot is presented, which applies the epipolar geometry and the 1D trifocal tensor to drive the robot to a desired configuration. The whole motion process is divided into three steps. Firstly, an epipole-based control law is designed to make the robot rotate in place until the camera points to the desired position. The 1D trifocal tensor is then used in the second translation step to reach the desired place. Finally, the desired configuration is reached through a pure rotation using the epipolar geometry. The stability of the proposed control system is proved based on linear system control theory and Lyapunov theory. Simulation results are given to illustrate the effectiveness of the proposed controller.

关键词： Geometry Linear systems Visualization Tensors Simulation Switches Control systems

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A simulation framework for ultrasound-guided minimally invasive robotic breast surgery

A simulation framework for ultrasound-guided minimally invas...

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2022 IEEE International Conference on robotics and Biomimetics, ROBIO 2022

作者： Zhang, Le Ye, Yanchen Niu, Baoshan Xiong, Genliang Yang, Dapeng State Key Laboratory of Robotics and System Harbin Institute of Technology Yikuang Street NanGang District HeilongJiang Harbin China School of Mechanical and Automotive Engineering Shanghai University of Engineering Science Longteng Rd 333 Shanghai201620 China

ISBN: (纸本)9781665481090

Surgical simulation plays an essential role for surgeons to familiarize themselves with surgical procedures and improve the success rate of surgery. In this paper, a flexible and easy-extendable intervention surgery simulation framework was presented, which can perform virtual simulation training and realize synchronous interaction between the real and virtual environment. In particular for breast surgery, the simulation framework was exemplified for an ultrasound-guided minimally invasive robotic breast surgery. The framework used Visual Studio®(Microsoft, USA) and Chai3D open graphics library to realize the virtual surgery environment, and integrated the anti-collision warning of the robotic arms and teleoperation communication support. A layered deformation model of breast was established based on the Mass-Spring Model to simulate the real-time deformation of breast during puncture surgery. In addition, due to the hyperelasticity and great deformation characteristics of breast soft tissue, we further used an improved meshless Radial Point Interpolation Method to improve the simulation accuracy of breast soft tissue deformation model. Finally, experiments on robot pressing a rectangular parallelepiped breast phantom were carried out to verify the simulation accuracy of the deformation model. © 2022 IEEE.

关键词： Tissue

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