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Modeling and control of a rigid-flexible coupling robot for narrow space manipulations

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science china(Technological sciences) 2025年第2期68卷 136-152页

作者： Kuangda CHEN Huan ZHAO Jiexin ZHANG Mei FENG Yiwei WANG Jinliang WANG Han DING State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Key Laboratory of CNC Equipment Reliability Ministry of EducationJilin UniversityChangchun 130021China School of Medical Equipment science and Engineering Huazhong University of Science and TechnologyWuhan 430074China

Narrow space manipulations are crucial for equipment maintenance,as they eliminate the need for disassembly,thus reducing costs and increasing ***-driven flexible robots possess exceptional capabilities in maneuvering through narrow spaces,thanks to their interaction compliance and distal ***,their inherent low stiffness causes a decline in the location accuracy of the robot and could even lead to manipulation *** address this challenge,this paper proposes a novel type of rigid-flexible coupling robot,which increases the stiffness of the robot while ensuring the reachability within a narrow *** achieve high-accuracy location in a narrow space,kinematic and control methods are ***,the robot forward kinematics are uniformly represented,and the closed-form inverse kinematics solution is ***,in cases where the robot's structure fails to align with Pieper's solution,a two-stage search strategy is utilized to solve the inverse kinematics,resulting in a high success rate of 99.1%.Based on the proposed kinematics,a rigid-dominated control method is then proposed to facilitate localization and pose alignment of target objects in narrow *** practical comparative experiments show that the proposed robot has the capability of high accuracy control in narrow spaces.

关键词： narrow space manipulation rigid-flexible coupling robot kinematics rigid-dominated control

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Rapid reduction of air pollution and short-term exposure risks in china

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Journal of Environmental sciences 2025年第3期149卷 126-138页

作者： Hao Fan Chuanfeng Zhao Yikun Yang Xingchuan Yang State Key Joint Laboratory of Environmental Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China Laboratory for Climate and Ocean-Atmospheric Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China College of Resource Environment and Tourism Capital Normal UniversityBeijing 100048China

With the continuous control of anthropogenic emissions,china’s air quality has improved significantly in recent *** this background,research on how the short-term exposure risks caused by air pollution in china have changed is *** study utilized hourly concentration data from ground observation stations and the official air quality guidelines of the Ministry of Ecology and Environment of china and the World Health Organization as standards to systematically investigate the spatiotemporal characteristics and short-term exposure risks of air pollution in china from 2015 to *** results indicate that various atmospheric pollutants except for ozone showed a decreasing trend ***,both single pollutant air pollution days(SAPDs)and multiple pollutant air pollution days(MAPDs)showed varying degrees of reduction within 15 and 25 days,*** was dominated mainly by excessive PM_(2.5)and PM_(10)pollutants,while MAPD was dominated mainly by excessive pollutant combinations,including PM_(2.5)+PM_(10),CO+PM_(2.5)+PM_(10),and SO_(2)+PM_(2.5)+PM_(10).As the concentration of atmospheric pollutants decreased,the total excess risk(ER)decreased yearly from 2015 to 2022,but there were significant regional ***,the ER is less than 0.25%in southern china,in the range of 0.25%-0.5%in the North china Plain and some cities in the northeast,and higher than 1%in the *** matter is currently the primary pollutant posing short-term exposure risk in china,especially due to the impact of sandstorm *** study indicates that china’s atmospheric cleaning action is significantly beneficial for reducing health risks.

关键词： Air pollution Emission-reduction Total excess risk Particulate matter china

A water probe for direct pH measurement of individual particles via micro-Raman spectroscopy

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Journal of Environmental sciences 2025年第3期149卷 200-208页

作者： Xiaoyu Cui Mingjin Tang Tong Zhu School of Environmental science and Engineering Tianjin UniversityTianjin 300072China BIC-ESAT and SKL-ESPC College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

The acidity of atmospheric aerosols influences fundamental physicochemical processes that affect climate and human *** recently developed a novel and facilewater-probebased method for directly measuring of the pH for micrometer-size droplets,providing a promising technique to better understand aerosol acidity in the *** complex chemical composition of fine particles in the ambient air,however,poses certain challenges to using a water-probe for pH measurement,including interference from interactions between compositions and the influence of similar compositions on water *** explore the universality of our method,it was employed to measure the pH of ammonium,nitrate,carbonate,sulfate,and chloride *** pH of particles covering a broad range(0–14)were accurately determined,thereby demonstrating that our method can be generally applied,even to alkaline ***,a standard spectral library was developed by integrating the standard spectra of common hydrated ions extracted through the *** library can be employed to identify particle composition and overcome the spectral overlap problem resulting from similar *** the spectral library,all ions were identified and their concentrations were determined,in turn allowing successful pH measurement of multicomponent(ammonium-sulfate-nitrate-chloride)*** into the synergistic effect of Cl^(–),NO_(3)^(–),and NH_(4)^(+)depletion obtained with our approach revealed the interplay between pH and volatile *** the ubiquity of component partitioning and pH variation in particles,the water probemay provide a new perspective on the underlying mechanisms of aerosol aging and aerosol–cloud interaction.

关键词： Particle pH Water probe Standard spectral library Micro-Raman spectroscopy Direct measurement

Design and preparation of a sintered Nd-Y-Fe-B magnet with high magnetic properties via multi-main-phase process and subsequent grain boundary diffusion

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Journal of Rare Earths 2025年第2期43卷 304-311,I0003页

作者： Fugang Chen Suxin Lu Jie Wang Yong Zhao Wenqiang Zhao Zhi Xu School of Materials science and Engineering Jiangsu University of Science and TechnologyZhenjiang212100China Baotou Tianshi Rare Earth New Materials Co. Ltd.Baotou014030China Jiangsu Yangzi Xinfu Shipbuilding Co. Ltd.Taixing225453China

A sintered Nd-Y-Fe-B magnet was designed and manufactured by the multi-main-phase *** distributed Y in the magnet decreases the adverse magnetic weakening effect of Y on the *** boundary diffusion process(GBDP)was conducted to further enhance the coercivity of the Nd-Y-Fe-B *** coercivity increases significantly from 884 to 1741 kA/m after GBDP with Pr_(60)Tb_(10)Cu_(30)*** mechanism of the coercivity enhancement is discussed based on the microstructure *** simulation reveals that when the diffused Tb-rich shell thickness is lower than 12 nm the c-plane shell(perpendicular to the c-axis)is much more effective in enhancing the coercivity than the side plane shell(parallel to the c-axis).But when the Tb-rich shell thickness is above12 nm the side plane shell contributes more to the coercivity *** results in this work can help to design and manufacture Nd-Fe-B magnets with low cost and high magnetic properties.

关键词： Rare earths Nd-Fe-B magnets Multi-main-phase process Grain boundary diffusion Micromagnetic simulation

Heterogeneous interface enhanced polyurethane/MXene@Fe_(3)O_(4)composite elastomers for electromagnetic wave absorption and thermal conduction

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International Journal of Minerals,Metallurgy and Materials 2025年第3期32卷 728-737页

作者： Xin An Zhaoxu Sun Jiahui Shen Jiajia Zheng Aixi Sun Xiping Li Shaohua Jiang Yiming Chen Key Laboratory of Urban Rail Transit Intelligent Operation and Maintenance Technology&Equipment of Zhejiang Province College of EngineeringZhejiang Normal UniversityJinhua 321004China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037China

The development of high-performance functional composites has become a research hotspot in response to the hazards of over-heating and electromagnetic radiation in modern electronic ***,we grew magnetic Fe_(3)O_(4)particles in situ on the MXene layer to obtain an MXene@Fe_(3)O_(4)composite with rich heterogeneous *** to the unique heterostructure and the synergistic effects of multiple electromagnetic wave absorption mechanisms,the composite achieved a minimum reflection loss of-27.14 dB and an effect-ive absorption bandwidth of 2.05 GHz at an absorption thickness of 2 ***,the MXene@Fe_(3)O_(4)composite could be encapsu-lated in thermoplastic polyurethane(TPU)via thermal *** obtained composite elastomer exhibited a strong tensile strength,and its thermal diffusivity was 113%higher than that of pure *** additional mechanical properties and thermal conduction features render this composite elastomer an advanced electromagnetic absorber to adapt to the ever-changing environment for expanding practical applications.

关键词： composite elastomer MXene electromagnetic wave absorption thermal conduction

Arsenic methylation and microbial communities in paddy soils under alternating anoxic and oxic conditions

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Journal of Environmental sciences 2025年第2期148卷 468-475页

作者： Jing Liu Rui Pei Runzeng Liu Chuanyong Jing Wenjing Liu Shandong Key Laboratory of Environmental Processes and Health School of Environmental Science and EngineeringShandong UniversityQingdao 266237China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Arsenic(As)methylation in soils affects the environmental behavior of As,excessive accumulation of dimethylarsenate(DMA)in rice plants leads to straighthead disease and a serious drop in crop *** the mobility and transformation of methylated arsenic in redox-changing paddy fields is crucial for food ***,soils including unarsenic contaminated(N-As),low-arsenic(L-As),medium-arsenic(M-As),and high-arsenic(H-As)soils were incubated under continuous anoxic,continuous oxic,and consecutive anoxic/oxic treatments respectively,to profile arsenic methylating process and microbial species involved in the As *** anoxic-oxic(A-O)treatment,methylated arsenic was significantly increased once oxygen was introduced into the incubation *** methylated arsenic concentrations were up to 2-24 times higher than those in anoxic(A),oxic(O),and oxic-anoxic(O-A)treatments,under which arsenic was methylated slightly and then decreased in all four As concentration *** fact,the most plentiful arsenite S-adenosylmethionine methyltransferase genes(arsM)contributed to the increase in As ***(40.8%-62.4%),Firmicutes(3.5%-15.7%),and Desulfobacterota(5.3%-13.3%)were the major microorganisms related to this *** microbial increasedmarkedly and played more important roles after oxygen was introduced,indicating that they were potential keystone microbial groups for As methylation in the alternating anoxic(flooding)and oxic(drainage)*** novel findings provided newinsights into the reoxidation-driven arsenic methylation processes and the model could be used for further risk estimation in periodically flooded paddy fields.

关键词： Arsenic methylation Anoxic-oxic Straighthead disease arsM gene Microbial community

Biomaterial-based Flexible Stretchable Sensor Devices:Classification,Composition and Their Multifunctional Integrated Applications

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Journal of Bionic Engineering 2025年第1期22卷 12-46页

作者： Lu Wang Langyuan Cao Jianhua Fan Junqiu Zhang Cheng Ma Zhiwu Han College of Food science and Engineering Jilin UniversityChangchun130062China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130025China Key Laboratory of Bionics Engineering of Ministry of Education Jilin UniversityChangchun130022China

Flexible sensors,a class of devices that can convert external mechanical or physical signals into changes in resistance,capacitance,or current,have developed rapidly since the concept was first *** to the special properties and naturally occurring excellent microstructures of biomaterials,it can provide more desirable properties to flexible *** paper systematically discusses the commonly used biomaterials for bio-based flexible devices in current research applications and their deployment in preparing flexible sensors with different *** to the characteristics of other properties and application requirements of biomaterials,the mechanisms of their functional group properties,special microstructures,and bonding interactions in the context of various sensing applications are presented in *** practical application scenarios of biomaterial-based flexible devices are highlighted,including human-computer interactions,energy harvesting,wound healing,and related biomedical ***,this paper also reviews in detail the limitations of biobased materials in the construction of flexible devices and presents challenges and trends in the development of biobased flexible sensors,as well as to better explore the properties of biomaterials to ensure functional synergy within the composite materials.

关键词： Biomaterials Flexible devices Sensing properties Bonding of groups Electromechanical properties Structural properties

Multifunctional and reprogrammable 4D pixel mechanical metamaterials

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INTERNATIONAL JOURNAL OF EXTREME MANUFACTURING 2025年第1期7卷 595-608页

作者： Xin, Xiaozhou Lin, Cheng Li, Bingxun Zhang, Ruikang Zeng, Chengjun Liu, Liwu Liu, Yanju Leng, Jinsong Harbin Inst Technol HIT Dept Astronaut Sci & Mech POB 30192 West Dazhi St Harbin 150001 Peoples R China Harbin Inst Technol HIT Ctr Composite Mat & Struct POB 3011 2 Yikuang St Harbin 150080 Peoples R China

Metamaterials have exotic physical properties that rely on the construction of their underlying architecture. However, the physical properties of conventional mechanical metamaterials are permanently programmed into their periodic interconnect configurations, resulting in their lack of modularity, scalable fabrication, and programmability. Mechanical metamaterials typically exhibit a single extraordinary mechanical property or multiple extraordinary properties coupled together, making it difficult to realize multiple independent extraordinary mechanical properties. Here, the pixel mechanics metamaterials (PMMs) with multifunctional and reprogrammable properties are developed by arraying uncoupled constrained individual modular mechanics pixels (MPs). The MPs enable controlled conversion between two extraordinary mechanical properties (multistability and compression-torsion coupling deformation). Each MP exhibits 32 independent and reversible room temperature programming configurations. In addition, the programmability of metamaterials is further enhanced by shape memory polymer (SMP) and 4D printing, greatly enriching the design freedom. For the PMM consisting of m x n MPs, it has 32((m x n)) independent room temperature programming configurations. The application prospects of metamaterials in the vibration isolation device and energy absorption device with programmable performance have been demonstrated. The vibration isolation frequencies of the MP before and after programming were [0 Hz-5.86 Hz], [0 Hz-13.67 Hz and 306.64 Hz-365.23 Hz]. The total energy absorption of the developed PMM can be adjusted controllably in the range of 1.01 J-3.91 J. Six standard digital logic gates that do not require sustained external force are designed by controlling the closure between the modules. This design paradigm will facilitate the further development of multifunctional and reprogrammable metamaterials.

关键词： 4D printing shape memory polymer pixel mechanical metamaterials multistable compression-twist coupling metamaterials digital logic gates

Effects of microstructures on deformation and damage of thermomechanical fatigue in nickel-base single crystal superalloys

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Chinese Journal of Aeronautics 2025年第2期38卷 541-558页

作者： Cheng LUO Huang YUAN School of Aerospace Engineering Tsinghua UniversityBeijing 100084China Institute of Aero Engines Tsinghua UniversityBeijing 100084China

Thermomechanical Fatigue (TMF) is one of the most dangerous failure modes of high-temperature structures. The effect of coarsened and rafted microstructures on the TMF behavior of Nickel-Base Single Crystal Superalloys (NBSX) was experimentally studied. TMF tests under In-Phase (IP) and Out-of-Phase (OP) paths revealed significant variations in TMF life reduction. Cyclic deformation behaviors of alloys with different microstructures were compared. The effect of microstructure on TMF damage mechanisms was unveiled from characterizations of fracture surfaces and longitudinal sections by scanning electronic microscope and optical microscope. A transition from mode-I to crystallographic fracture in the coarsened alloy during IP-TMF was observed and discussed. Due to the degraded microstructure, the dispersed distribution of crystal slips was distinguished in the coarsened and rafted alloys. The competitive or synergetic interactions among oxidation-assisted mode-I opening, casting pore-related mode-I creep and crystallographic slipping were discussed. This study underscores the complex interplay among microstructure, deformation behaviors and damage mechanisms, offering valuable insights into alloy performance under TMF conditions.

关键词： Thermomechanical fatigue Rafting and coarsening Single crystal superalloy Damage mechanism Life reduction Fatigue-creep-oxidation