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A Numerical Study on the Propagation Mechanisms of Hydraulic Fractures in Fracture-Cavity Carbonate Reservoirs

Computer Modeling in Engineering & Sciences 2021年第5期127卷 575-598页

作者： Fang Shi Daobing Wang Xiaogang Chen Jiangsu Key Laboratory of Advanced Manufacturing Technology Huaiyin Institute of TechnologyHuai’an223003China School of Mechanical Engineering Beijing Key Laboratory of Pipeline Critical Technology and Equipment for Deepwater Oil&Gas DevelopmentBeijing Institute of Petrochemical TechnologyBeijing102617China

Field data suggests that carbonate reservoirs contain abundant natural fractures and *** propagation mechanisms of hydraulic fractures in fracture-cavity reservoirs are different from conventional reservoirs on account of the stress concentration surrounding *** this paper,we develop a fully coupled numerical model using the extended finite element method(XFEM)to investigate the behaviors and propagation mechanisms of hydraulic fractures in fracture-cavity *** results show that a higher lateral stress coefficient can enhance the influence of the natural cavity,causing a more curved fracture ***,lower confining stress or smaller in-situ stress difference can reduce this influence,and thus contributes to the penetration of the hydraulic fracture towards the *** fluid viscosity and high fluid pumping rate are both able to attenuate the effect of the *** frictional natural fracture connected to the cavity can significantly change the stress distribution around the cavity,thus dramatically deviates the hydraulic fracture from its original propagation *** is also found that the natural cavity existing between two adjacent fracturing stages will significantly influence the stress distribution between fractures and is more likely to result in irregular propagation paths compared to the case without a cavity.

关键词： Hydraulic fracturing fracture-cavity reservoir crack propagation XFEM

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Dynamic Obstacle Avoidance for Magnetic Helical Microrobots Based on Deep Reinforcement Learning

Dynamic Obstacle Avoidance for Magnetic Helical Microrobots ...

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2024 IEEE International Conference on Real-Time Computing and robotics, RCAR 2024

作者： Qiu, Yukang Hou, Yaozhen Yang, Haotian Gao, Yigao Huang, Hen-Wei Shi, Qing Huang, Qiang Wang, Huaping Beijing Institute of Technology Intelligent Robotics Institute School of Mechatronical Engineering Beijing100081 China Harvard Medical School Laboratory for Translational Engineering CambridgeMA02139 United States Beijing Institute of Technology Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing100081 China Ministry of Education Key Laboratory of Biomimetic Robots and Systems Beijing Institute of Technology Beijing100081 China

ISBN: (纸本)9798350372601

Magnetic helical microrobots hold immense promise in biomedical domains owing to their compact size and efficient propulsion capabilities. However, navigating these microrobots through dynamic and unstructured environments, particularly when encountering numerous dynamic obstacles, remains a formidable challenge. In the study, a control framework based on deep reinforcement learning (DRL) with the objective of guiding a microrobot through dynamic obstacles towards specified target goals is introduced. Initially, we design and fabricate a microdrill capable of propulsion via external magnetic rotating fields produced by our magnetic actuation system. Subsequently, we construct a custom training environment, adhering to the OpenAI gym interface, to serve as the simulator for training purposes. Utilizing the proximal policy optimization algorithm, we conduct training of the navigation policy within this simulator. Simulations and experimental validations conducted in dynamic environments affirms the efficacy of the proposed method. © 2024 IEEE.

关键词： Microrobots

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Kinematics Analysis and Singularity Avoidance of a Parallel Mechanism with Kinematic Redundancy

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Chinese Journal of Mechanical Engineering 2022年第5期35卷 244-261页

作者： Chaoyu Shen Haibo Qu Sheng Guo Xiao Li Robotics Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China China Waterborne Transport Research Institute Beijing 100088China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control TechnologyMinistry of EducationBeijing Jiaotong UniversityBeijing 100044China

The kinematic redundancy is considered as a way to improve the performance of the parallel *** this paper,the kinematics performance of a three degree-of-freedom parallel mechanism with kinematic redundancy(3-DOF PM-KR)and the influence of redundant parts on the PM-KR are ***,the kinematics model of the PM-KR is *** inverse solutions,the Jacobian matrix,and the workspace of the PM-KR are ***,the influence of redundancy on the PM-KR is *** there exists kinematic redundancy,the PM-KR possesses fault-tolerant *** locking one actuating joint or two actuating joints simultaneously,the fault-tolerant workspace is *** the position of the redundant part is changed,the workspace and singularity will be *** results show that kinematic redundancy can be used to avoid ***,the simulations are performed to prove the theoretical analysis.

关键词： Parallel mechanism Kinematic redundancy Singularity Simulation analysis

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Channel-distribution Hybrid Deep Learning for sEMG-based Gesture Recognition

Channel-distribution Hybrid Deep Learning for sEMG-based Ges...

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2022 IEEE International Conference on robotics and Biomimetics, ROBIO 2022

作者： Lu, keyi Guo, Hao Qi, Fei Gong, Peihao Gu, Zhihao Sun, Lining Huang, Haibo School of Mechanical and Electric Engineering Jiangsu Provincial Key Laboratory of Advanced Robotics Soochow University Suzhou215123 China School of Mechanical and Electric Engineering Soochow University Suzhou215123 China

ISBN: (纸本)9781665481090

In recent years, CNNs (Convolutional Neural Networks) with their powerful feature representation and feature learning capabilities, have played an important role in gesture recognition tasks based on sparse multichannel surface EMG signals. As each muscle group in the upper limb plays a different role in a particular hand movement, we propose a hybrid CNN model that considers the spatial distribution of muscle groups in the myoelectric channel to improve the accuracy of hand gesture recognition. The model takes the spectrogram of CWT (Continuous Wavelet Transform) as input, based on the spatial distribution of channels, decomposes all channels into multiple input streams, lets the CNN learn the features of each stream separately, and gradually fuses (slowly fusion) the features learned by each stream, and then performs gesture classification. Finally, the results of several of these stream-division methods are fused for decision making to obtain classification accuracies. The proposed model was validated and tested on the Nina Pro DB4 dataset, and the average accuracy was improved compared to both traditional machine learning methods and multi-stream CNN models that do not take into account the spatial distribution of channels. © 2022 IEEE.

关键词： Neural network models

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A hygro-thermo-mechanical constitutive model for shape memory polymers filled with nano-carbon powder

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International Journal of Smart and Nano Materials 2021年第3期12卷 286-306页

作者： Jianping Gu Xiaopeng Zhang Hao Duan Mengqi Wan Huiyu Sun Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology School of Materials Science and EngineeringNanjing Institute of TechnologyNanjingChina State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjingChina

The nano-carbon powders are often used as fillers to endow the shape memory polymers(SMPs)with *** has been found that the shape memory effects(SMEs)of SMPs filled with nano-carbon powder can be triggered both by temperature and by *** reveal the driving mechanism of SMEs,a constitutive model for describing the thermally activated and moisture activated SMEs of these shape memory polymer composite(SMPCs)is developed *** both of the SMEs share the same driving mechanism,the variable moisture is incorporated into the framework of a thermo-mechanical modeling approach to disclose the effect of moisture on the thermoviscoelastic *** SMPCs are regarded as isotropic materials and the effect of carbon powder on the mechanical properties of the matrix is also considered in the *** the complete recovery may not be reached even they are exposed to the stimulus environment long enough,the blocking mechanism is also considered *** is the mainly new contribution compared to the early *** the method of parameter determination presented here,the effectiveness of the proposed hygro-thermo-mechanical constitutive model is confirmed by comparing the model results with the test data of uniaxial deformation from the literature.

关键词： Shape memory polymer composites nano-carbon powder hygro-thermomechanical constitutive model thermodynamics internal state variables

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High-rate proton storage in aqueous electrolyte based small organic molecules materials

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Electrochimica Acta 2025年 532卷

作者： Shi, Yanjun Qiu, Huifang Xu, Zhihui Chen, Miaomei Gao, Haiguang Yu, Xiaofei Xu, Juan Cao, Jianyu Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology School of Petrochemical Engineering Changzhou University 1 Gehu Road Jiangsu Changzhou213164 China

Aqueous proton battery (APB) is a promising energy storage system due to the smallest ion size and fastest kinetics of proton. However, its application development is still limited by unsatisfactory rate and cycling performance. Herein, two organic compounds, BPD and 2F-BPD, are demonstrated as anode for reversibly storage proton in an acid electrolyte, which exhibited high-rate capability. The full batteries were constructed by matching the two anodes with a high performance of CuHCF cathode. The BPD//CuHCF full battery achieved high capacities of 182 mAh g−1 at 1 A g−1 and 151 mAh g−1 at 20 A g−1 and an extremely long cycling stability over 10000 cycles with 79 % capacity retention at 10 A g−1. Due to the hydrophobic effect of the F atom in 2F-BPD and extremely severe hydrogen evolution reaction (HER) in the 2F-BPD//CuHCF full battery, the capacity of the full battery based 2F-BPD anode is slightly lower and decays rapidly. The proton storage of BPD was further analyzed by ex-situ characterizations. During charging, the C=O and C=N bonds in the BPD anode combine with protons in the aqueous electrolyte. This work will inspire small organic molecules to achieve beneficial results in APBs and thus promote a breakthrough in the field of large-scale energy storage. © 2025 Elsevier Ltd

关键词： Battery storage

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Structural modelling of rotary three-dimensional braiding preforms 6

Structural modelling of rotary three-dimensional braiding pr...

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6th International Conference on Computer Information Science and Application technology, CISAT 2023

作者： Wang, Hui Long, Wanxin Wang, Jinhuo Chen, Yizhe Yang, Liu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of Technology Wuhan430070 China Hubei Longzhong Laboratory Xiangyang441000 China Fujian Key Laboratory of Functional Materials and Applications Xiamen University of Technology Xiamen361024 China Jiangsu Xinyang New Material Co. Ltd. Yangzhou225000 China Guangrui Group Xiangyang441000 China

ISBN: (纸本)9781510668546

This work aims to study the modelling method of braiding preforms based on the rotary 3D braiding process. In the rotary 3D braiding process, the carrier is driven by the horn-gear through its alternating rotation, thus yarns interlacing to form the braiding preform. Encoding the horn-gear and the carrier to study the movement law of the carrier. The trajectory of the carrier and the height of the braiding node jointly determine the spatial topology structure of the braiding preform. The yarn trajectory is fitted and optimized using the cubic B-spline curve, Python script is written to drive CATIA to establish a solid model of the braiding preform and a fabric structure simulation interface is developed using PyQt5. Experiments on the braiding of irregular components are conducted to compare the actual braiding fabric with the corresponding model. The result indicates that the braiding algorithm could accurately record the coordinates of the trajectory points of the carrier;The fitted yarn trajectory conforms to the actual trajectory of the yarn;The simulated preform structure is consistent with the actual braiding preform. Therefore, it can be concluded that the modelling method is suitable for structural simulation of various cross-section braiding preforms. © 2023 SPIE.

关键词： Yarn

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Anti-diabetic potential of apigenin,luteolin,and baicalein via partially activating PI3K/Akt/GLUT-4 signaling pathways in insulin-resistant HepG2 cells

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Food Science and Human Wellness 2023年第6期12卷 1991-2000页

作者： Lingchao Miao Haolin Zhang Meng Sam Cheong Ruting Zhong Paula Garcia-Oliveira Miguel A.Prieto Ka-Wing Cheng Mingfu Wang Hui Cao Shaoping Nie Jesus Simal-Gandara Wai San Cheang Jianbo Xiao Institute of Chinese Medical Sciences University of MacaoMacao 999078China Department of Analytical Chemistry and Food Science Faculty of Food Science and TechnologyUniversity of Vigo-Ourense CampusOurense E-32004Spain Institute for Advanced Study Shenzhen UniversityShenzhen 508060China School of Biological Sciences The University of Hong KongHong Kong 999077China College of Food Science and Technology Guangdong Ocean UniversityGuangdong Provincial Key Laboratory of Aquatic Product Processing and SafetyGuangdong Province Engineering Laboratory for Marine Biological ProductsGuangdong Provincial Engineering Technology Research Center of SeafoodKey Laboratory of Advanced Processing of Aquatic Product of Guangdong Higher Education InstitutionZhanjiang 524088China State Key Laboratory of Food Science and Technology China-Canada Joint Lab of Food Science and Technology(Nanchang)Nanchang UniversityNanchang 330047China International Research Center for Food Nutrition and Safety Jiangsu UniversityZhenjiang 212013China

Dietary flavonoids are abundant in natural plants and possess multiple pharmacological and nutritional *** this study,apigenin,luteolin,and baicalein were chosen to evaluate their anti-diabetic effect in high-glucose and dexamethasone induced insulin-resistant(IR)HepG2 *** flavonoids improves the glucose consumption and glycogen synthesis abilities in IR-HepG2 cells via activating glucose transporter protein 4(GLUT4)and phosphor-glycogen synthase kinase(GSK-3β).These fl avonoids signifi cantly inhibited the production of reactive oxygen species(ROS)and advanced glycation end-products(AGEs),which were closely related to the suppression of the phosphorylation form of NF-κB and *** expression levels of insulin receptor substrate-1(IRS-1),insulin receptor substrate-2(IRS-2)and phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)pathway in IR-HepG2 cells were all partially activated by the fl avonoids,with variable ***,the intracellular metabolic conditions of the fl avonoids were also evaluated.

关键词： Apigenin Luteolin Baicalein Insulin-resistant HepG2 cells Signaling pathway Reactive oxygen species(ROS) advanced glycation end-products(AGEs) Glycogen synthase kinase(GSK-3β) Glucose transporter protein 4(GLUT4)

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Solution-processed quantum-dot light-emitting diodes combining ultrahigh operational stability,shelf stability,and luminance

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npj Flexible Electronics 2022年第1期6卷 949-955页

作者： Zi Ye Mengyu Chen Xingtong Chen Wenchen Ma Xiaojuan Sun Longjia Wu Xiongfeng Lin Yu Chen Song Chen Suzhou Key Laboratory of Novel Semiconductor-optoelectronics Materials and Devices College of ChemistryChemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsuPR China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySuzhouJiangsuPR China School of Optoelectronic Science and Engineering&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhouJiangsuPR China TCL Corporate Research ShenzhenGuangdongPR China

The shelf-stability issue,originating from the ZnO-induced positive aging effect,poses a significant challenge to industrializing the display technology based on solution-processed quantum-dot light-emitting diodes(QLEDs).Currently,none of the proposed solutions can simultaneously inhibit exciton quenching caused by the ZnO-based electron-transporting layer(ETL)and retain other advantages of *** in this work,we propose a bilayer design of ETL in which a buffer layer assembled of SnO_(2) nanoparticles(NPs)suppresses the QD-ETL exciton quenching and tunes charge balance while ZnO NPs provide high electron *** a result,the bottom-emitting QLED combining capped ZnO and SnO_(2) buffer exhibit a maximum luminance over 100,000 cd m^(−2) and a T95 operational lifetime averaging 6200 h at 1000 cd m^(−2) on the premise of entirely inhibiting positive aging.

关键词： diodes stability quantum

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Experimental Study on the Improvement of Yaw Stability by Coordination Control between the Caudal Fin and Anal Fin

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Journal of Bionic Engineering 2022年第5期19卷 1261-1271页

作者： Jiang Ding Changzhen Zheng Chaocheng Song Qiyang Zuo Yaohui Xu Bingbing Dong Jiaxu Cui Kai He Fengran Xie College of Mechanical Engineering Guangxi UniversityNanning 530004China Guangxi Key Lab of Manufacturing System and Advanced Manufacturing Technology Nanning 530004China Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China Shenzhen Key Laboratory of Precision Engineering Shenzhen 518055China University of Chinese Academy of Sciences Beijing 100049China College of Mechanical Automation Wuhan University of Science and TechnologyWuhan 430000China SIAT Branch Shenzhen Institute of Artificial Intelligence and Robotics for SocietyShenzhen 518055China

Due to the unique locomotion,the head-shaking problem of biomimetic robotic fish inevitably occurs during rectilinear locomotion,which strongly hinders its practical *** this paper,we experimentally study this problem by proposing the method of coordination control between the caudal fin and anal ***,an untethered biomimetic robotic fish,equipped with an anal fin,a caudal fin and two pectoral fins,is developed as the experimental ***,a Central Pattern Generator(CPG)-based controller is used to coordinate the motions of the anal fin and caudal ***,extensive experiments are conducted to explore different combinations of the flapping frequencies,the flapping amplitudes,and the phase differences between the anal fin and caudal ***,through proper control of the anal fin,the amplitude of the yaw motion can be as small as 4.32°,which sees a 65%improvement compared to the scenario without anal fin,and a 57%improvement compared to that with a stationary anal *** paper provides a novel way to alleviate the head-shaking problem for biomimetic robotic fish,and first test this method on an untethered,freely swimming robotic platform,which can shed light on the development of underwater robotics.

关键词： Biomimetic robotic fish Anal fin Head-shaking Yaw stability

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