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Deep Learning for EMG-based Human-Machine Interaction:A Review 被引量:15
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作者 Dezhen Xiong Daohui Zhang +1 位作者 Xingang Zhao Yiwen Zhao 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2021年第3期512-533,共22页
Electromyography(EMG)has already been broadly used in human-machine interaction(HMI)applications.Determining how to decode the information inside EMG signals robustly and accurately is a key problem for which we urgen... Electromyography(EMG)has already been broadly used in human-machine interaction(HMI)applications.Determining how to decode the information inside EMG signals robustly and accurately is a key problem for which we urgently need a solution.Recently,many EMG pattern recognition tasks have been addressed using deep learning methods.In this paper,we analyze recent papers and present a literature review describing the role that deep learning plays in EMG-based HMI.An overview of typical network structures and processing schemes will be provided.Recent progress in typical tasks such as movement classification,joint angle prediction,and force/torque estimation will be introduced.New issues,including multimodal sensing,inter-subject/inter-session,and robustness toward disturbances will be discussed.We attempt to provide a comprehensive analysis of current research by discussing the advantages,challenges,and opportunities brought by deep learning.We hope that deep learning can aid in eliminating factors that hinder the development of EMG-based HMI systems.Furthermore,possible future directions will be presented to pave the way for future research. 展开更多
关键词 ACCURACY deep learning electromyography(EMG) human-machine interaction(HMI) ROBUSTNESS
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Voices of Mother's Interaction with Midwives in Natural Childbirth: A Qualitative Study 被引量:1
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作者 Firoozeh Mirzaee Rabor Ali Taghipour Khadigeh Mirzaii Najmabadi 《Health》 2015年第1期153-160,共8页
Interaction between mothers and midwives during natural childbirth is one of the important factors in relationship between mothers and midwives in natural childbirth. In this qualitative study we explored experiences ... Interaction between mothers and midwives during natural childbirth is one of the important factors in relationship between mothers and midwives in natural childbirth. In this qualitative study we explored experiences of mothers and midwives in interaction with each other in natural childbirth. This study was a part of a larger study which was carried out in Iran in 2013-2014. A total of 23 participants participated in this study. 12 primiparous and multiparous women planned to have natural deliveries and 11 midwives were purposefully included for semi-structured in-depth interviews in this study. For analysis and interpretation of mothers’ and midwives’ experience, conventional content analysis was used. Data were coded in MAXqda software (version 2). Interaction between mothers and midwives could be organized and categorized in one theme “relationship”. This theme consists of two subthemes: “respect for the mother” and “interaction” and five categories: “Feeling confidence, Feeling satisfaction, Associated with sensory relationship, Understanding mother’s situation, Understanding the meaning of interaction”. Good relationship between mothers and midwives in natural childbirth could improve the experience of natural childbirth for mothers. This experience could increase woman’s tendency toward natural birth instead of cesarean section in future pregnancies. Findings of this study can be seen as a challenge for health care professionals and policy makers to upgrade care of natural childbirth based on women’s preferences and needs. 展开更多
关键词 natural CHILDBIRTH Relationship interaction Qualitative Study Content Analysis
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An investigation into natural vibrations of fluid-structure interaction systems subject to Sommerfeld radiation condition 被引量:2
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作者 Jing Tang Xing 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第1期69-82,共14页
A fluid-structure interaction system subject to Sommerfeld's condition is defined as a Sommerfeld system which is divided into three categories: Fluid Sommerfeld (FS) System, Solid Sommerfeld (SS) System and Flu... A fluid-structure interaction system subject to Sommerfeld's condition is defined as a Sommerfeld system which is divided into three categories: Fluid Sommerfeld (FS) System, Solid Sommerfeld (SS) System and Fluid Solid Sommerfeld (FSS) System of which Sommerfeld conditions are imposed on a fluid boundary only, a solid boundary only and both fluid and solid boundaries, respectively. This paper follows the previous initial results claimed by simple examples to further mathematically investigate the natural vibrations of generalized Sommerfeld systems. A new parameter representing the speed of radiation wave for generalized 3-D problems with more complicated boundary conditions is introduced into the Sommerfeld condition which allows investigation of the natural vibrations of a Sommerfeld system involving both free surface and compressible waves. The mathematical demonstrations and selected examples confirm and reveal the natural behaviour of generalized Sommerfeld systems defined above. These generalized conclusions can be used in theoretical or engineering analysis of the vibrations of various Sommerfeld systems in engineering. 展开更多
关键词 Sommerfeld system Complex natural frequencies Fluid-structure interaction Complex energyflow identity Speed of radiation wave
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Interactions of naturally occurring compounds with antimicrobials
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作者 Izabela Malczak Anna Gajda 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2023年第12期1452-1470,共19页
Antibiotics are among the most often used medications in human healthcare and agriculture.Overusing these substances can lead to complications such as increasing antibiotic resistance in bacteria or a toxic effect whe... Antibiotics are among the most often used medications in human healthcare and agriculture.Overusing these substances can lead to complications such as increasing antibiotic resistance in bacteria or a toxic effect when administering large amounts.To solve these problems,new solutions in antibacterial therapy are needed.The use of natural products in medicine has been known for centuries.Some of them have antibacterial activity,hence the idea to combine their activity with commercial antibiotics to reduce the latter's use.This review presents collected information on natural compounds(terpenes,alkaloids,flavonoids,tannins,sulfoxides,and mycotoxins),of which various drug interactions have been observed.Many of the indicated compounds show synergistic or additive interactions with antibiotics,which suggests their potential for use in antibacterial therapy,reducing the toxicity of the antibiotics used and the risk of further development of bacterial resistance.Unfortunately,there are also compounds which interact antagonistically,potentially hindering the therapy of bacterial infection.Depending on its mechanism of action,each compound can behave differently in combination with different antibiotics and when acting against various bacterial strains. 展开更多
关键词 interactionS Antimicrobials natural compounds ANTIBIOTICS
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BLIND SPEECH SEPARATION FOR ROBOTS WITH INTELLIGENT HUMAN-MACHINE INTERACTION
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作者 Huang Yulei Ding Zhizhong +1 位作者 Dai Lirong Chen Xiaoping 《Journal of Electronics(China)》 2012年第3期286-293,共8页
Speech recognition rate will deteriorate greatly in human-machine interaction when the speaker's speech mixes with a bystander's voice. This paper proposes a time-frequency approach for Blind Source Seperation... Speech recognition rate will deteriorate greatly in human-machine interaction when the speaker's speech mixes with a bystander's voice. This paper proposes a time-frequency approach for Blind Source Seperation (BSS) for intelligent Human-Machine Interaction(HMI). Main idea of the algorithm is to simultaneously diagonalize the correlation matrix of the pre-whitened signals at different time delays for every frequency bins in time-frequency domain. The prososed method has two merits: (1) fast convergence speed; (2) high signal to interference ratio of the separated signals. Numerical evaluations are used to compare the performance of the proposed algorithm with two other deconvolution algorithms. An efficient algorithm to resolve permutation ambiguity is also proposed in this paper. The algorithm proposed saves more than 10% of computational time with properly selected parameters and achieves good performances for both simulated convolutive mixtures and real room recorded speeches. 展开更多
关键词 Blind Source Separation (BSS) Blind deconvolution Speech signal processing human-machine interaction Simultaneous diagonalization
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A Robotic Teleoperation System for Precise Robotic Manipulation by Human-Machine Interaction
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作者 SUN Fuchun GUO Di CHEN Yang 《上海航天(中英文)》 CSCD 2022年第4期114-127,共14页
Teleoperation is of great importance in the area of robotics,especially when people are unavailable in the robot workshop.It provides a way for people to control robots remotely using human intelligence.In this paper,... Teleoperation is of great importance in the area of robotics,especially when people are unavailable in the robot workshop.It provides a way for people to control robots remotely using human intelligence.In this paper,a robotic teleoperation system for precise robotic manipulation is established.The data glove and the 7-degrees of freedom(DOFs)force feedback controller are used for the remote control interaction.The control system and the monitor system are designed for the remote precise manipulation.The monitor system contains an image acquisition system and a human-machine interaction module,and aims to simulate and detect the robot running state.Besides,a visual object tracking algorithm is developed to estimate the states of the dynamic system from noisy observations.The established robotic teleoperation systemis applied to a series of experiments,and high-precision results are obtained,showing the effectiveness of the physical system. 展开更多
关键词 TELEOPERATION human-machine interaction precise manipulation visual object tracking robotich and manipulation
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Research of Natural Gesture Recognition and Interactive Technology Compatible with YCb Crand HSV Color Space 被引量:1
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作者 YE Wen-yu FENG Kai-ping +1 位作者 LUO Na PAN Yang 《Computer Aided Drafting,Design and Manufacturing》 2015年第3期10-17,共8页
In view of the current gesture recognition algorithm based on skin color segmentation is not flexible and has weak resistance to the environment, this paper puts forward a new method of skin color modeling to improve ... In view of the current gesture recognition algorithm based on skin color segmentation is not flexible and has weak resistance to the environment, this paper puts forward a new method of skin color modeling to improve the adaptability of gesture segmentation when it face to different states. The modeling built by double color space instead of only one is compatible both in YCbCr and HSV color space to training the Gaussian model which can update the threshold value for binarization. Finally, this paper designed a natural gesture recognition and interactive systems based on the double color space model. It has shown that the system has a good interactive experience in different environments. 展开更多
关键词 human-machine interaction gesture recognition skin color segmentation feature extraction
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Web GIS Human-Machine Interactive Interface Design with VISI
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作者 XIONG Lan HU Hongliang +2 位作者 DU Qingyun HUANG Maojun WANG Mingjun 《Geo-Spatial Information Science》 2008年第1期66-70,共5页
The fusion of VlSI (visual identity system Internet), digital maps and Web GIS is presented. Web GIS interface interactive design with VISI needs to consider more new factors. VISI can provide the design principle, ... The fusion of VlSI (visual identity system Internet), digital maps and Web GIS is presented. Web GIS interface interactive design with VISI needs to consider more new factors. VISI can provide the design principle, elements and contents for the Web GIS. The design of the Wuhan Bus Search System is fulfilled to confirm the validity and practicability of the fusion. 展开更多
关键词 Web GIS human-machine interactive interface design VISI
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Designing interactive glazing through an engineering psychology approach:Six augmented reality scenarios that envision future car human-machine interface
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作者 Wei LIU Yancong ZHU +5 位作者 Ruonan HUANG Takumi OHASHI Jan AUERNHAMMER Xiaonan ZHANG Ce SHI Lu WANG 《Virtual Reality & Intelligent Hardware》 2023年第2期157-170,共14页
Background With an increasing number of vehicles becoming autonomous,intelligent,and connected,paying attention to the future usage of car human-machine interface with these vehicles should become more relevant.Severa... Background With an increasing number of vehicles becoming autonomous,intelligent,and connected,paying attention to the future usage of car human-machine interface with these vehicles should become more relevant.Several studies have addressed car HMI but were less attentive to designing and implementing interactive glazing for every day(autonomous)driving contexts.Methods Reflecting on the literature,we describe an engineering psychology practice and the design of six novel future user scenarios,which envision the application of a specific set of augmented reality(AR)support user interactions.Additionally,we conduct evaluations on specific scenarios and experiential prototypes,which reveal that these AR scenarios aid the target user groups in experiencing a new type of interaction.The overall evaluation is positive with valuable assessment results and suggestions.Conclusions This study can interest applied psychology educators who aspire to teach how AR can be operationalized in a human-centered design process to students with minimal pre-existing expertise or minimal scientific knowledge in engineering psychology. 展开更多
关键词 Augmented reality interactive glazing Engineering psychology Car human-machine interface Human-computer interaction Human-centered design User experience Generation Z
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Application of Natural Language Processing in Virtual Experience AI Interaction Design
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作者 Ziqian Rong 《Journal of Intelligent Learning Systems and Applications》 2024年第4期403-417,共15页
This paper investigates the application of Natural Language Processing (NLP) in AI interaction design for virtual experiences. It analyzes the impact of various interaction methods on user experience, integrating Virt... This paper investigates the application of Natural Language Processing (NLP) in AI interaction design for virtual experiences. It analyzes the impact of various interaction methods on user experience, integrating Virtual Reality (VR) and Augmented Reality (AR) technologies to achieve more natural and intuitive interaction models through NLP techniques. Through experiments and data analysis across multiple technical models, this study proposes an innovative design solution based on natural language interaction and summarizes its advantages and limitations in immersive experiences. 展开更多
关键词 natural Language Processing Virtual Reality Augmented Reality interaction Design User Experience
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Human Interaction Dynamics for Its Use in Mobile Robotics:Impedance Control for Leader-follower Formation 被引量:9
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作者 Daniel Herrera Flavio Roberti +1 位作者 Marcos Toibero Ricardo Carelli 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第4期696-703,共8页
A complete characterization of the behavior in human-robot interactions(HRI) includes both: the behavioral dynamics and the control laws that characterize how the behavior is regulated with the perception data. In thi... A complete characterization of the behavior in human-robot interactions(HRI) includes both: the behavioral dynamics and the control laws that characterize how the behavior is regulated with the perception data. In this way, this work proposes a leader-follower coordinate control based on an impedance control that allows to establish a dynamic relation between social forces and motion error. For this, a scheme is presented to identify the impedance based on fictitious social forces, which are described by distance-based potential fields.As part of the validation procedure, we present an experimental comparison to select the better of two different fictitious force structures. The criteria are determined by two qualities: least impedance errors during the validation procedure and least parameter variance during the recursive estimation procedure.Finally, with the best fictitious force and its identified impedance,an impedance control is designed for a mobile robot Pioneer 3AT,which is programmed to follow a human in a structured scenario.According to results, and under the hypothesis that moving like humans will be acceptable by humans, it is believed that the proposed control improves the social acceptance of the robot for this kind of interaction. 展开更多
关键词 Human modeling human-machine interaction impedance control robot dynamics social robotics
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Magnetic Array Assisted Triboelectric Nanogenerator Sensor for Real‑Time Gesture Interaction 被引量:8
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作者 Ken Qin Chen Chen +7 位作者 Xianjie Pu Qian Tang Wencong He Yike Liu Qixuan Zeng Guanlin Liu Hengyu Guo Chenguo Hu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2021年第3期168-176,共9页
In human-machine interaction,robotic hands are useful in many scenarios.To operate robotic hands via gestures instead of handles will greatly improve the convenience and intuition of human-machine interaction.Here,we ... In human-machine interaction,robotic hands are useful in many scenarios.To operate robotic hands via gestures instead of handles will greatly improve the convenience and intuition of human-machine interaction.Here,we present a magnetic array assisted sliding triboelectric sensor for achieving a real-time gesture interaction between a human hand and robotic hand.With a finger’s traction movement of flexion or extension,the sensor can induce positive/negative pulse signals.Through counting the pulses in unit time,the degree,speed,and direction of finger motion can be judged in realtime.The magnetic array plays an important role in generating the quantifiable pulses.The designed two parts of magnetic array can transform sliding motion into contact-separation and constrain the sliding pathway,respectively,thus improve the durability,low speed signal amplitude,and stability of the system.This direct quantization approach and optimization of wearable gesture sensor provide a new strategy for achieving a natural,intuitive,and real-time human-robotic interaction. 展开更多
关键词 Sliding triboelectric sensor Magnetic array GESTURE Real-time human-machine interaction
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Natural killer cells in hepatitis C:Current progress 被引量:5
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作者 Joo Chun Yoon Chang Mo Yang +1 位作者 Youkyong Song Jae Myun Lee 《World Journal of Gastroenterology》 SCIE CAS 2016年第4期1449-1460,共12页
Patients infected with the hepatitis C virus(HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairmen... Patients infected with the hepatitis C virus(HCV) are characterized by a high incidence of chronic infection, which results in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. The functional impairment of HCV-specific T cells is associated with the evolution of an acute infection to chronic hepatitis. While T cells are the important effector cells in adaptive immunity, natural killer(NK) cells are the critical effector cells in innate immunity to virus infections. The findings of recent studies on NK cells in hepatitis C suggest that NK cell responses are indeed important in each phase of HCV infection. In the early phase, NK cells are involved in protective immunity to HCV. The immune evasion strategies used by HCV may target NK cells and might contribute to the progression to chronic hepatitis C. NK cells may control HCV replication and modulate hepatic fibrosis in the chronic phase. Further investigations are, however, needed, because a considerable number of studies observed functional impairment of NK cells in chronic HCV infection. Interestingly, the enhanced NK cell responses during interferon-α-based therapy of chronic hepatitis C indicate successful treatment. In spite of the advances in research on NK cells in hepatitis C, establishment of more physiological HCV infection model systems is needed to settle unsolved controversies over the role and functional status of NK cells in HCV infection. 展开更多
关键词 HEPATITIS C virus natural KILLER cell Accessorycell Virus-host interaction IMMUNE EVASION Acutehepatitis CHRONIC HEPATITIS Treatment response
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Dynamic Analysis of A 5-MW Tripod Offshore Wind Turbine by Considering Fluid–Structure Interaction 被引量:4
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作者 ZHANG Li-wei LI Xin 《China Ocean Engineering》 SCIE EI CSCD 2017年第5期559-566,共8页
Fixed offshore wind turbines usually have large underwater supporting structures. The fluid influences the dynamic characteristics of the structure system. The dynamic model of a 5-MW tripod offshore wind turbine cons... Fixed offshore wind turbines usually have large underwater supporting structures. The fluid influences the dynamic characteristics of the structure system. The dynamic model of a 5-MW tripod offshore wind turbine considering the pile-soil system and fluid structure interaction (FSI) is established, and the structural modes in air and in water are obtained by use of ANSYS. By comparing low-order natural frequencies and mode shapes, the influence of sea water on the free vibration characteristics of offshore wind turbine is analyzed. On basis of the above work, seismic responses under excitation by E1-Centro waves are calculated by the time-history analysis method. The results reveal that the dynamic responses such as the lateral displacement of the foundation and the section bending moment of the tubular piles increase substantially under the influence of the added-mass and hydrodynamic pressure of sea water. The method and conclusions presented in this paper can provide a theoretical reference for structure design and analysis of offshore wind turbines fixed in deep seawater. 展开更多
关键词 5-MW tripod offshore wind turbine fluid-structure interaction natural frequency seismic analysis hydrodynamic pressure
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Interpreting and Extracting Open Knowledge for Human-Robot Interaction 被引量:2
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作者 Dongcai Lu Xiaoping Chen 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2017年第4期686-695,共10页
A more natural way for non-expert users to express their tasks in an open-ended set is to use natural language. In this case,a human-centered intelligent agent/robot is required to be able to understand and generate p... A more natural way for non-expert users to express their tasks in an open-ended set is to use natural language. In this case,a human-centered intelligent agent/robot is required to be able to understand and generate plans for these naturally expressed tasks. For this purpose, it is a good way to enhance intelligent robot's abilities by utilizing open knowledge extracted from the web, instead of hand-coded knowledge. A key challenge of utilizing open knowledge lies in the semantic interpretation of the open knowledge organized in multiple modes, which can be unstructured or semi-structured, before one can use it.Previous approaches used a limited lexicon to employ combinatory categorial grammar(CCG) as the underlying formalism for semantic parsing over sentences. Here, we propose a more effective learning method to interpret semi-structured user instructions. Moreover, we present a new heuristic method to recover missing semantic information from the context of an instruction. Experiments showed that the proposed approach renders significant performance improvement compared to the baseline methods and the recovering method is promising. 展开更多
关键词 Human-robot interaction intelligent robot natural language processing open knowledge semantic role labeling
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Theoretical Study on the Intermolecular Interactions of Tetrazole Dimers 被引量:1
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作者 ZHOU Su-Qin JU Xue-Hai XIAO He-Ming 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第10期1203-1210,共8页
Tetrazole monomers (Ⅰ, Ⅱ) and all of their possible stable dimers (1, 2, 3, 4, 5, 6, 7 and 8) were fully optimized by DFT method at the B3LYP/6-311++G^** level. Among the eight dimers, there were two 1H-tetr... Tetrazole monomers (Ⅰ, Ⅱ) and all of their possible stable dimers (1, 2, 3, 4, 5, 6, 7 and 8) were fully optimized by DFT method at the B3LYP/6-311++G^** level. Among the eight dimers, there were two 1H-tetrazole dimers, three 2H-tetrazole dimers and three hetero dimers of 1H-tetrazole and 2H-tetrazole. Vibrational frequencies were calculated to ascertain that each structure was stable (no imaginary frequencies). The basis set superposition errors (BSSE) are 2.78, 2.28, 2.97, 2.75, 2.74, 2.18, 1.23 and 3.10 kJ/mol, and the zero point energy (ZPE) corrections for the interaction energies are 4.88, 4.18, 3.87, 3.65, 3.54, 3.22, 2.87 and 4.34 kJ/mol for 1, 2, 3, 4, 5, 6, 7 and 8, respectively. After BSSE and ZPE corrections, the greatest corrected intermolecular interaction energy of the dimers is -43.71 kJ/mol. The charge redistribution mainly occurs on the adjacent N-H…N atoms between submolecules. The charge transfer between two subsystems is very small. Natural bond orbital (NBO) analysis was performed to reveal the origin of the interaction. Based on the statistical thermodynamic method, the standard thermodynamic functions, heat capacities (C^0P), entropies (S^0T) and thermal corrections to enthalpy (H^0T), and the changes of thermodynamic properties from monomer to dimer in the temperature range of 200.00 K to 700 K have been obtained. 1H-tetrazole monomer can spontaneously turn into two stable dimers at 298.15 K. 展开更多
关键词 tetrazole dimer intermolecular interaction DFT natural bond orbital thermodynamic properties
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Skin‑Inspired Ultra‑Tough Supramolecular Multifunctional Hydrogel Electronic Skin for Human–Machine Interaction 被引量:1
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作者 Kun Chen Kewei Liang +4 位作者 He Liu Ruonan Liu Yiying Liu Sijia Zeng Ye Tian 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第8期1-19,共19页
Multifunctional supramolecular ultra-tough bionic e-skin with unique durability for human–machine interaction in complex scenarios still remains challenging.Herein,we develop a skininspired ultra-tough e-skin with tu... Multifunctional supramolecular ultra-tough bionic e-skin with unique durability for human–machine interaction in complex scenarios still remains challenging.Herein,we develop a skininspired ultra-tough e-skin with tunable mechanical properties by a physical cross-linking salting-freezing-thawing method.The gelling agent(β-Glycerophosphate sodium:Gp)induces the aggregation and binding of PVA molecular chains and thereby toughens them(stress up to 5.79 MPa,toughness up to 13.96 MJ m^(−3)).Notably,due to molecular self-assembly,hydrogels can be fully recycled and reprocessed by direct heating(100°C for a few seconds),and the tensile strength can still be maintained at about 100%after six recoveries.The hydrogel integrates transparency(>60%),super toughness(up to 13.96 MJ m^(−3),bearing 1500 times of its own tensile weight),good antibacterial properties(E.coli and S.aureus),UV protection(Filtration:80%–90%),high electrical conductivity(4.72 S m^(−1)),anti-swelling and recyclability.The hydrogel can not only monitor daily physiological activities,but also be used for complex activities underwater and message encryption/decryption.We also used it to create a complete finger joint rehabilitation system with an interactive interface that dynamically presents the user’s health status.Our multifunctional electronic skin will have a profound impact on the future of new rehabilitation medical,human–machine interaction,VR/AR and the metaverse fields. 展开更多
关键词 Ultra-tough hydrogel SUPRAMOLECULAR Flexible electronics Knuckle training human-machine interaction
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Failure Patterns and Mechanisms of Hydraulic Fracture Propagation Behavior in the Presence of Naturally Cemented Fractures 被引量:1
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作者 Daobing Wang Fang Shi +2 位作者 Hao Qin Dongliang Sun Bo Yu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第3期891-914,共24页
In this study,we use the extended finite element method(XFEM)with a consideration of junction enrichment functions to investigate the mechanics of hydraulic fractures related to naturally cemented fractures.In the pro... In this study,we use the extended finite element method(XFEM)with a consideration of junction enrichment functions to investigate the mechanics of hydraulic fractures related to naturally cemented fractures.In the proposed numerical model,the lubrication equation is adopted to describe the fluid flow within fractures.The fluid-solid coupling systems of the hydraulic fracturing problem are solved using the Newton-Raphson method.The energy release rate criterion is used to determine the cross/arrest behavior between a hydraulic fracture(HF)and a cemented natural fracture(NF).The failure patterns and mechanisms of crack propagation at the intersection of natural fractures are discussed.Simulation results show that after crossing an NF,the failure mode along the cemented NF path may change from the tensile regime to the shear or mixed-mode regime.When an advancing HF kinks back toward the matrix,the failure mode may gradually switch back to the tensile-dominated regime.Key factors,including the length of the upper/lower portion of the cemented NF,horizontal stress anisotropy,and the intersection angle of the crack propagation are investigated in detail.An uncemented or partially cemented NF will form a more complex fracture network than a cemented NF.This study provides insight into the formation mechanism of fracture networks in formations that contain cemented NF. 展开更多
关键词 Hydraulic fracturing natural fractures crack propagation unconventional reservoirs mechanical interaction JOINTS
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Flexible and multifunctional triboelectric nanogenerator based on liquid metal/polyvinyl alcohol hydrogel for energy harvesting and self-powered wearable human-machine interaction 被引量:2
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作者 Hou-Wang Zhou Cong Zhao +7 位作者 Ze-Yu Zhao Jun-Chen Jiang Hui-Le Jin Shun Wang Shuang Pan Min-Yi Xu Yi-Huang Chen Hai-Ming Jin 《Rare Metals》 SCIE EI CAS CSCD 2024年第3期1186-1196,共11页
Hydrogel-based triboelectric nanoge nerator(TENG)has a promising applied prospect in wearable electronic devices.However,its low performance,poor stability,insufficient recyclability and inferior self-healing seriousl... Hydrogel-based triboelectric nanoge nerator(TENG)has a promising applied prospect in wearable electronic devices.However,its low performance,poor stability,insufficient recyclability and inferior self-healing seriously hinder its development.Herein,we report a robust route to a liquid metal(LM)/polyvinyl alcohol(PVA)hydrogel-based TENG(LP-TENG).Owing to the intrinsically liquid feature of conductive LM within the flexible PVA hydrogel,the as-prepared LP-TENG exhibited comprehensiye advantages of adaptability,biocompatibility,outstanding electrical performance,superior stability,recyclability and diverse applications,which were unattainable by traditional systems.Concretely,the LP-TENG delivered appealing open circuit voltage of 250 V,short circuit current of 4μA and transferred charge of 120 nC with high stability,outperforming most advanced TENG systems.The LP-TENG was successfully employed for versatile applications with multifunctionality,including human motion detection,handwriting recognition,energy collection,message transmission and human-machine interaction.This work presents significant prospects for crafting advanced materials and devices in the fields of wearable electronics,flexible skin and smart robots. 展开更多
关键词 Liquid metal HYDROGEL Wearable TENG Multifunctionality human-machine interaction
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Covalent intermolecular interaction of the nitric oxide dimer (NO)_2
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作者 张辉 郑桂丽 +2 位作者 吕刚 耿轶钊 纪青 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第9期177-181,共5页
Covalent bonds arise from the overlap of the electronic clouds in the internucleus region, which is a pure quantum effect and cannot be obtained in any classical way. If the intermolecular interaction is of covalent c... Covalent bonds arise from the overlap of the electronic clouds in the internucleus region, which is a pure quantum effect and cannot be obtained in any classical way. If the intermolecular interaction is of covalent character, the result from direct applications of classical simulation methods to the molecular system would be questionable. Here, we analyze the special intermolecular interaction between two NO molecules based on quantum chemical calculation. This weak intermolecular interaction, which is of covalent character, is responsible for the formation of the NO dimer,(NO)2, in its most stable conformation, a cis conformation. The natural bond orbital(NBO) analysis gives an intuitive illustration of the formation of the dimer bonding and antibonding orbitals concomitant with the breaking of the πbonds with bond order 0.5of the monomers. The dimer bonding is counteracted by partially filling the antibonding dimer orbital and the repulsion between those fully or nearly fully occupied nonbonding dimer orbitals that make the dimer binding rather weak. The direct molecular mechanics(MM) calculation with the UFF force fields predicts a trans conformation as the most stable state, which contradicts the result of quantum mechanics(QM). The lesson from the investigation of this special system is that for the case where intermolecular interaction is of covalent character, a specific modification of the force fields of the molecular simulation method is necessary. 展开更多
关键词 nitric oxide dimer intermolecular interaction natural orbital covalent bond
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