Procedures of preparation of numerical analysis,consisting in a simulation of cooperation of three different media: steel,liquid and gas undergoes dynamic load were discussed.Modelling of the initial static load of th...Procedures of preparation of numerical analysis,consisting in a simulation of cooperation of three different media: steel,liquid and gas undergoes dynamic load were discussed.Modelling of the initial static load of the mechanical system was presented.By using the MSC.Software products the following exemplary computer simulations were made: dynamic load impact on the hydraulic leg as well as effectiveness of the hydraulic leg protection against overload with help of gas accumulator.展开更多
China-made medical equipment combines quality and low price to grow African market TEN years ago,Li Shunhai went to Africa once a year,where he slept little and ate poorly while installing and adjusting X-ray machines...China-made medical equipment combines quality and low price to grow African market TEN years ago,Li Shunhai went to Africa once a year,where he slept little and ate poorly while installing and adjusting X-ray machines.A decade later,traveling for business in African countries has become commonplace for the senior engineer at Beijing Wandong Medical Equipment Co.Ltd.,a leading Chinese medical equipment展开更多
AS the world changes, Africa＇s financial policies are gradually changing, too. Today, large donations from donor countries and organizations are important for countries across Africa to develop, but parallel to this,...AS the world changes, Africa＇s financial policies are gradually changing, too. Today, large donations from donor countries and organizations are important for countries across Africa to develop, but parallel to this, populations across the continent must have access to feasible and coherent financial tools.展开更多
Just one day after the official announcement for the end of H1N1 influenza by WHO,Kumarasamy et al.(2010)reported the emergence of a new global health problem,which was caused by Gram-negative Enterobacteriaceae with ...Just one day after the official announcement for the end of H1N1 influenza by WHO,Kumarasamy et al.(2010)reported the emergence of a new global health problem,which was caused by Gram-negative Enterobacteriaceae with resistance to a broad range of beta-lactam antibiotics due to the presence of blaNDM-1 that encodes NDM-1,which inactivates allβ-lactam antibiotics.Now,the NDM-1 superbugs have been identified in multiple countries,including India,Pakistan,UK,USA,Japan,Brazil,Canada,Australia,France,Holland and China.A Belgian patient who was infected in Pakistan following a car accident became the first known fatality from NDM-1.NDM-1 belongs to metallo-β-lactamase(MBL),which is a characterized family of carbapenem antibiotics inactivating enzymes.However,the broad resistance to currently available antibiotics and the strong capability of contemporary horizontal gene transfer(HGT)bring the threat from NDM-1 bacteria into top news throughout the world.In the neverstopped game between human being and pathogens,we are in check again.展开更多
Journal Introduction″International Journal of Plant Engineering and Management″is in the charge of Ministry of Industry and Information Technology of the People′s Republic of China,and organized by Northwestern Pol...Journal Introduction″International Journal of Plant Engineering and Management″is in the charge of Ministry of Industry and Information Technology of the People′s Republic of China,and organized by Northwestern Polytechnical University.It is a kind of English aca-demic quarterly publication publicly issued at home and abroad.Plant engineering and management is a comprehensive interdisciplinary subject mainly reporting academic research on the application technology of equipment and industry management.It is of the characteristics of reporting both engineering and management while giving more priority to engineering as well as mechanics and electrics while giving priority to mechanics.Its contents involves technology,economy,management etc.展开更多
On November 26th,Zhengzhou Textile Machinery Co.,Ltd.(hereinafter referred to as"ZFJ")signed an order for a high-speed intelligent wide-width wetmethod spunlace production line with Hubei Lijie New Material ...On November 26th,Zhengzhou Textile Machinery Co.,Ltd.(hereinafter referred to as"ZFJ")signed an order for a high-speed intelligent wide-width wetmethod spunlace production line with Hubei Lijie New Material Technology Co.,Ltd.(hereinafter referred to as"Hubei Lijie").This cooperation marks a further consolidation of ZFJ's leading position in the nonwoven fabric equipment market in Hubei Province and lays a solid foundation for deeper cooperation between the two companies in the future.展开更多
East Africa’s construction boom draws Chinese heavy machinery manufacturers and distributors The booming construction of new housing and commercial units has led to unprecedented demand for heavy construction equipme...East Africa’s construction boom draws Chinese heavy machinery manufacturers and distributors The booming construction of new housing and commercial units has led to unprecedented demand for heavy construction equipment in Nairobi,Kenya.展开更多
The reliable operation of power grid secondary equipment is an important guarantee for the safety and stability of the power system.However,various defects could be produced in the secondary equipment during longtermo...The reliable operation of power grid secondary equipment is an important guarantee for the safety and stability of the power system.However,various defects could be produced in the secondary equipment during longtermoperation.The complex relationship between the defect phenomenon andmulti-layer causes and the probabilistic influence of secondary equipment cannot be described through knowledge extraction and fusion technology by existing methods,which limits the real-time and accuracy of defect identification.Therefore,a defect recognition method based on the Bayesian network and knowledge graph fusion is proposed.The defect data of secondary equipment is transformed into the structured knowledge graph through knowledge extraction and fusion technology.The knowledge graph of power grid secondary equipment is mapped to the Bayesian network framework,combined with historical defect data,and introduced Noisy-OR nodes.The prior and conditional probabilities of the Bayesian network are then reasonably assigned to build a model that reflects the probability dependence between defect phenomena and potential causes in power grid secondary equipment.Defect identification of power grid secondary equipment is achieved by defect subgraph search based on the knowledge graph,and defect inference based on the Bayesian network.Practical application cases prove this method’s effectiveness in identifying secondary equipment defect causes,improving identification accuracy and efficiency.展开更多
With the widespread adoption of digital equipment in intelligent substations,testing digital signals in power systems has become an important role for relay protection test equipment.Testing and calibrating digital si...With the widespread adoption of digital equipment in intelligent substations,testing digital signals in power systems has become an important role for relay protection test equipment.Testing and calibrating digital signals require high accuracy.However,existing methods have low precision,cannot be calibrated at full range for all indexes,and have complex configuration,making them unsuitable for routine calibration work.To solve the above problems,a novel calibration method is designed and implemented using field programmable gate array(FPGA)to achieve accurate input and output time control.Accurate calibration relies on multiple forms of traceability including theoretical value traceability based on waveform comparison,time scale value traceability based on accurate time stamps,and algorithm traceability based on typical algorithms.Compared with other existing methods,the proposed approach reduces the mean absolute error of action time and time measurement by 92.88%,effectively addressing a key industry challenge and offering a valuable reference for further research,application,and standardization.展开更多
In the construction and maintenance for large space equipment,it is essential to ensure the control accuracy and improve the dexterity of the space manipulator.In this paper,a FiniteTime Convergence Kinematic Control(...In the construction and maintenance for large space equipment,it is essential to ensure the control accuracy and improve the dexterity of the space manipulator.In this paper,a FiniteTime Convergence Kinematic Control(FTCKC)added with Acceleration Level Dexterity Optimization(ALDO)scheme is proposed to solve the kinematic uncertainty and dexterity optimization problems of redundant space manipulators.Concretely,distinguishing from the asymptotic convergence property of traditional adaptive Jacobian methods,the FTCKC scheme is adopted to construct the equality constraint to address the model uncertainty problem,and its error can converge within a finite time.Subsequently,the dexterity index is reconstructed at acceleration level by a multi-level target handling method.Then,the equality constraint,optimization task,and limit constraints are reformulated as a quadratic programming problem.Moreover,a Recurrent Neural Network(RNN)is engineered for the constructed FTCKC-ALDO scheme.Finally,the superiority of the FTCKC-ALDO-RNN scheme is verified by experiments.展开更多
The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Coval...The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.展开更多
The authors investigate a disturbance-compensating and energy-saving control method for air turbine spindles equipped with a rotation control system designed for use in ultra-precision milling. The controllability and...The authors investigate a disturbance-compensating and energy-saving control method for air turbine spindles equipped with a rotation control system designed for use in ultra-precision milling. The controllability and energy-conserving characteristics of the proposed method using the proposed pneumatic regulating device, called a high-precision quick-response pneumatic pressure regulator, were demonstrated experimentally previously. Herein, the proposed rotation-controlled air turbine spindle is first summarised. Subsequently, the proposed rotation-controlled air turbine spindle is set to a milling machine and applied to the milling of an alloy tool steel, to gain data and validate the effectiveness of the in-process tool wear estimation method that have been recently developed and proposed by the authors. Particularly, to evaluate the possibility of applying the proposed estimation method to three-dimensional milling, milling experiments where the air turbine spindle is set at a 45° incline were conducted and the results indicate a high possibility of the proposed method.展开更多
This study investigates the performance of a new compact(55 cm×56 cm×48 cm)in situ spin-exchange optical pumping ^(3)He neutron spin filter(NSF)system developed at the China Spallation Neutron Source.The enc...This study investigates the performance of a new compact(55 cm×56 cm×48 cm)in situ spin-exchange optical pumping ^(3)He neutron spin filter(NSF)system developed at the China Spallation Neutron Source.The enclosed NSF cell,filled with3He at 2.53 bar,achieved an initial ^(3)He polarization of approximately 60%.After subsequent improvements in the magnetic field and heating system,this in situ system achieved a ^(3)He polarization of 75.66%±0.09%,resulting in 96.30%neutron polarization at 2A.This highly compact in situ system is equipped with self-supportive features,pre-pumping capabilities,polarization maintenance,and a low-noise nuclear magnetic resonance system.These advantages significantly reduce the preparation time and simplify polarized neutron experiments,making it suitable for various neutron beamlines in China,particularly those with a limited sample space.These characteristics establish it as a quasi-standardized system that plays a vital role in polarized neutron experiments,including those involving polarized neutron imaging,neutron reflection,the performance calibration of polarized neutron instruments,and the neutron optics parity and time reversal experiment.展开更多
About this issue:Radar astronomy is a science that utilizes radar electromagnetic waves to study celestial bodies within and beyond the solar system,focusing mainly on planets,satellites and small bodies such as the M...About this issue:Radar astronomy is a science that utilizes radar electromagnetic waves to study celestial bodies within and beyond the solar system,focusing mainly on planets,satellites and small bodies such as the Moon,Mars,Venus and Saturn.Through radar electromagnetic wave detection,we are able to gain an in-depth understanding of these celestial bodies'internal structures,composition,distribution of water resources,magnetic fields,atmospheres,and other physical properties.This is of great significance for human beings to find a habitable environment in the solar system.At present,the observation methods of radar astronomy mainly rely on ground-based radio telescopes that actively emit electromagnetic waves.In recent years,with the continuous advancement of international deep space exploration,in-situ radar detection technology has gradually become an indispensable new tool for lunar and planetary radar astronomical observations.For example,China's Chang'e3,4,5 and 6 missions,as well as the Tianwen-1 mission to Mars and the United States'Perseverance rover,are equipped with radar payloads.These deep space exploration missions have expanded radar astronomy techniques to lunar and planetary surface observations,greatly enriching and promoting the scientific content and development of radar astronomy.For this reason,the editorial office invited Dr.Chunyu Ding from Shenzhen University and Dr.Yan Su from the National Astronomical Observatories,Chinese Academy of Sciences to co edit a special issue of radar astronomy.展开更多
Capturing ultrafast dynamics over a large momentum space is critical for revealing the relationship between the electronic and structural modulations in quantum materials.Here,by performing time-and angle-resolved pho...Capturing ultrafast dynamics over a large momentum space is critical for revealing the relationship between the electronic and structural modulations in quantum materials.Here,by performing time-and angle-resolved photoemission spectroscopy measurements at the Synergetic Extreme Condition User Facility(SECUF)equipped with an extreme ultraviolet light source,we reveal the ultrafast dynamics of a charge-density wave(CDW)material,1T-TiSe_(2),upon photoexcitation.Pump-induced CDW melting is revealed from two aspects:gap closing of the CDW at the Brillouin zone(BZ)center and weakening of the CDW folded band at the BZ boundary.By comparing the transient electronic structure and spectral weight over a large momentum space,we further reveal the carrier redistribution involving the excitation of electrons from theГpoint to the M point.This study provides a comprehensive picture of the physics and ultrafast dynamics of a CDW material across the entire BZ.展开更多
The evolution of information technology has propelled the advancement of sensors into a new era,referred to as Sensors 4.0^([1]).This era is characterized by the integration of key technological developments,including...The evolution of information technology has propelled the advancement of sensors into a new era,referred to as Sensors 4.0^([1]).This era is characterized by the integration of key technological developments,including the internet of things(IoT),Industry 4.0,big data,artificial intelligence(AI),robotics,and digital health.These innovations necessitate that sensors become increasingly interconnected and intelligent.The concept of"everything is connected"demands that sensors undertake a broader and more complex range of tasks,a challenge that conventional,bulky devices are ill-equipped to address.展开更多
Dear Editor,Active magnetic bearings(AMBs)are of considerable interest and significance in smart manufacturing due to their zero-friction and adaptivity to noncontact rotor rotations.This paper proposes an active levi...Dear Editor,Active magnetic bearings(AMBs)are of considerable interest and significance in smart manufacturing due to their zero-friction and adaptivity to noncontact rotor rotations.This paper proposes an active levitation control algorithm based on adaptive sliding mode control(ASMC)equipped with linear extended state observer(LESO).Sufficient conditions are derived to guarantee the asymptotical stability of the associated closed-loop system.Experiments are conducted on a real AMB-rotor platform to demonstrate the effectiveness and superiority of the proposed algorithm.展开更多
Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,an...Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection.展开更多
The multi-terminal direct current(DC)grid has extinctive superiorities over the traditional alternating current system in integrating large-scale renewable energy.Both the DC circuit breaker(DCCB)and the current flow ...The multi-terminal direct current(DC)grid has extinctive superiorities over the traditional alternating current system in integrating large-scale renewable energy.Both the DC circuit breaker(DCCB)and the current flow controller(CFC)are demanded to ensure the multiterminal DC grid to operates reliably and flexibly.However,since the CFC and the DCCB are all based on fully controlled semiconductor switches(e.g.,insulated gate bipolar transistor,integrated gate commutated thyristor,etc.),their separation configuration in the multiterminal DC grid will lead to unaffordable implementation costs and conduction power losses.To solve these problems,integrated equipment with both current flow control and fault isolation abilities is proposed,which shares the expensive and duplicated components of CFCs and DCCBs among adjacent lines.In addition,the complicated coordination control of CFCs and DCCBs can be avoided by adopting the integrated equipment in themultiterminal DC grid.In order to examine the current flow control and fault isolation abilities of the integrated equipment,the simulation model of a specific meshed four-terminal DC grid is constructed in the PSCAD/EMTDC software.Finally,the comparison between the integrated equipment and the separate solution is presented a specific result or conclusion needs to be added to the abstract.展开更多
Precision actuation is a foundational technology in high-end equipment domains,where stroke,velocity,and accuracy are critical for processing and/or detection quality,precision in spacecraft flight trajectories,and ac...Precision actuation is a foundational technology in high-end equipment domains,where stroke,velocity,and accuracy are critical for processing and/or detection quality,precision in spacecraft flight trajectories,and accuracy in weapon system strikes.Piezoelectric actuators(PEAs),known for their nanometer-level precision,flexible stroke,resistance to electromagnetic interference,and scalable structure,have been widely adopted across various fields.Therefore,this study focuses on extreme scenarios involving ultra-high precision(micrometer and beyond),minuscule scales,and highly complex operational conditions.It provides a comprehensive overview of the types,working principles,advantages,and disadvantages of PEAs,along with their potential applications in piezo-actuated smart mechatronic systems(PSMSs).To address the demands of extreme scenarios in high-end equipment fields,we have identified five representative application areas:positioning and alignment,biomedical device configuration,advanced manufacturing and processing,vibration mitigation,micro robot system.Each area is further divided into specific subcategories,where we explore the underlying relationships,mechanisms,representative schemes,and characteristics.Finally,we discuss the challenges and future development trends related to PEAs and PSMSs.This work aims to showcase the latest advancements in the application of PEAs and provide valuable guidance for researchers in this field.展开更多
文摘Procedures of preparation of numerical analysis,consisting in a simulation of cooperation of three different media: steel,liquid and gas undergoes dynamic load were discussed.Modelling of the initial static load of the mechanical system was presented.By using the MSC.Software products the following exemplary computer simulations were made: dynamic load impact on the hydraulic leg as well as effectiveness of the hydraulic leg protection against overload with help of gas accumulator.
文摘China-made medical equipment combines quality and low price to grow African market TEN years ago,Li Shunhai went to Africa once a year,where he slept little and ate poorly while installing and adjusting X-ray machines.A decade later,traveling for business in African countries has become commonplace for the senior engineer at Beijing Wandong Medical Equipment Co.Ltd.,a leading Chinese medical equipment
文摘AS the world changes, Africa＇s financial policies are gradually changing, too. Today, large donations from donor countries and organizations are important for countries across Africa to develop, but parallel to this, populations across the continent must have access to feasible and coherent financial tools.
文摘Just one day after the official announcement for the end of H1N1 influenza by WHO,Kumarasamy et al.(2010)reported the emergence of a new global health problem,which was caused by Gram-negative Enterobacteriaceae with resistance to a broad range of beta-lactam antibiotics due to the presence of blaNDM-1 that encodes NDM-1,which inactivates allβ-lactam antibiotics.Now,the NDM-1 superbugs have been identified in multiple countries,including India,Pakistan,UK,USA,Japan,Brazil,Canada,Australia,France,Holland and China.A Belgian patient who was infected in Pakistan following a car accident became the first known fatality from NDM-1.NDM-1 belongs to metallo-β-lactamase(MBL),which is a characterized family of carbapenem antibiotics inactivating enzymes.However,the broad resistance to currently available antibiotics and the strong capability of contemporary horizontal gene transfer(HGT)bring the threat from NDM-1 bacteria into top news throughout the world.In the neverstopped game between human being and pathogens,we are in check again.
文摘Journal Introduction″International Journal of Plant Engineering and Management″is in the charge of Ministry of Industry and Information Technology of the People′s Republic of China,and organized by Northwestern Polytechnical University.It is a kind of English aca-demic quarterly publication publicly issued at home and abroad.Plant engineering and management is a comprehensive interdisciplinary subject mainly reporting academic research on the application technology of equipment and industry management.It is of the characteristics of reporting both engineering and management while giving more priority to engineering as well as mechanics and electrics while giving priority to mechanics.Its contents involves technology,economy,management etc.
文摘On November 26th,Zhengzhou Textile Machinery Co.,Ltd.(hereinafter referred to as"ZFJ")signed an order for a high-speed intelligent wide-width wetmethod spunlace production line with Hubei Lijie New Material Technology Co.,Ltd.(hereinafter referred to as"Hubei Lijie").This cooperation marks a further consolidation of ZFJ's leading position in the nonwoven fabric equipment market in Hubei Province and lays a solid foundation for deeper cooperation between the two companies in the future.
文摘East Africa’s construction boom draws Chinese heavy machinery manufacturers and distributors The booming construction of new housing and commercial units has led to unprecedented demand for heavy construction equipment in Nairobi,Kenya.
基金supported by the State Grid Southwest Branch Project“Research on Defect Diagnosis and Early Warning Technology of Relay Protection and Safety Automation Devices Based on Multi-Source Heterogeneous Defect Data”.
文摘The reliable operation of power grid secondary equipment is an important guarantee for the safety and stability of the power system.However,various defects could be produced in the secondary equipment during longtermoperation.The complex relationship between the defect phenomenon andmulti-layer causes and the probabilistic influence of secondary equipment cannot be described through knowledge extraction and fusion technology by existing methods,which limits the real-time and accuracy of defect identification.Therefore,a defect recognition method based on the Bayesian network and knowledge graph fusion is proposed.The defect data of secondary equipment is transformed into the structured knowledge graph through knowledge extraction and fusion technology.The knowledge graph of power grid secondary equipment is mapped to the Bayesian network framework,combined with historical defect data,and introduced Noisy-OR nodes.The prior and conditional probabilities of the Bayesian network are then reasonably assigned to build a model that reflects the probability dependence between defect phenomena and potential causes in power grid secondary equipment.Defect identification of power grid secondary equipment is achieved by defect subgraph search based on the knowledge graph,and defect inference based on the Bayesian network.Practical application cases prove this method’s effectiveness in identifying secondary equipment defect causes,improving identification accuracy and efficiency.
基金supported by the Key Technologies R&D Program of Henan Province(No.242102211065)Postgraduate Education Reform and Quality Im-provement Project of Henan Province(No.YJS2025GZZ36).
文摘With the widespread adoption of digital equipment in intelligent substations,testing digital signals in power systems has become an important role for relay protection test equipment.Testing and calibrating digital signals require high accuracy.However,existing methods have low precision,cannot be calibrated at full range for all indexes,and have complex configuration,making them unsuitable for routine calibration work.To solve the above problems,a novel calibration method is designed and implemented using field programmable gate array(FPGA)to achieve accurate input and output time control.Accurate calibration relies on multiple forms of traceability including theoretical value traceability based on waveform comparison,time scale value traceability based on accurate time stamps,and algorithm traceability based on typical algorithms.Compared with other existing methods,the proposed approach reduces the mean absolute error of action time and time measurement by 92.88%,effectively addressing a key industry challenge and offering a valuable reference for further research,application,and standardization.
基金supported by the National Natural Science Foundation of China(Nos.92148203 and T2388101)。
文摘In the construction and maintenance for large space equipment,it is essential to ensure the control accuracy and improve the dexterity of the space manipulator.In this paper,a FiniteTime Convergence Kinematic Control(FTCKC)added with Acceleration Level Dexterity Optimization(ALDO)scheme is proposed to solve the kinematic uncertainty and dexterity optimization problems of redundant space manipulators.Concretely,distinguishing from the asymptotic convergence property of traditional adaptive Jacobian methods,the FTCKC scheme is adopted to construct the equality constraint to address the model uncertainty problem,and its error can converge within a finite time.Subsequently,the dexterity index is reconstructed at acceleration level by a multi-level target handling method.Then,the equality constraint,optimization task,and limit constraints are reformulated as a quadratic programming problem.Moreover,a Recurrent Neural Network(RNN)is engineered for the constructed FTCKC-ALDO scheme.Finally,the superiority of the FTCKC-ALDO-RNN scheme is verified by experiments.
基金financially supported by the National Natural Science Foundation of China (No.51972302)。
文摘The recovery of gold from waste electronic and electric equipment(WEEE) has gained great attention with the increased number of WEEE,because it can largely alleviate the pressure on the environment and resources.Covalent organic frameworks(COFs) are ideal adsorbents for gold recovery owing to their large surface area,good stability,easily functionalized ability,periodic structures,and definitive nanopores.Herein,a cyano-functionalized COF(COF-CN) with high crystallinity was large-scale prepared under mild conditions for the recovery of gold.The introduction of cyano groups enable COF-CN to exhibit excellent gold recovery performance,which possesses fast adsorption kinetics,high cycling stability,and adsorption capacity up to 663.67 mg/g.Excitingly,COF-CN showed extremely high selectivity for gold ions,even in the presence of various competing cations and anions.The COF-CN maintained excellent selectivity and removal efficiency in gold recovery experiments from WEEE.The facile synthesis of COF-CN and its outstanding selectivity in actual samples make it an attractive opportunity for practical gold recovery.
文摘The authors investigate a disturbance-compensating and energy-saving control method for air turbine spindles equipped with a rotation control system designed for use in ultra-precision milling. The controllability and energy-conserving characteristics of the proposed method using the proposed pneumatic regulating device, called a high-precision quick-response pneumatic pressure regulator, were demonstrated experimentally previously. Herein, the proposed rotation-controlled air turbine spindle is first summarised. Subsequently, the proposed rotation-controlled air turbine spindle is set to a milling machine and applied to the milling of an alloy tool steel, to gain data and validate the effectiveness of the in-process tool wear estimation method that have been recently developed and proposed by the authors. Particularly, to evaluate the possibility of applying the proposed estimation method to three-dimensional milling, milling experiments where the air turbine spindle is set at a 45° incline were conducted and the results indicate a high possibility of the proposed method.
基金supported by the National Science Fund for Distinguished Young Scholars(Grant No.12425512)the National Key Research and Development Program of China(Grant No.2020YFA0406000)+4 种基金the National Natural Science Foundation of China(Grant No.11875265)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(Grant No.ZDKYYQ20190004)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2019B1515120079)Dongguan Introduction Program of Leading Innovative and Entrepreneurial Talents(Grant No.20191122)Guangdong Provincial Key Laboratory of Extreme Conditions,Dongguan Key Laboratory。
文摘This study investigates the performance of a new compact(55 cm×56 cm×48 cm)in situ spin-exchange optical pumping ^(3)He neutron spin filter(NSF)system developed at the China Spallation Neutron Source.The enclosed NSF cell,filled with3He at 2.53 bar,achieved an initial ^(3)He polarization of approximately 60%.After subsequent improvements in the magnetic field and heating system,this in situ system achieved a ^(3)He polarization of 75.66%±0.09%,resulting in 96.30%neutron polarization at 2A.This highly compact in situ system is equipped with self-supportive features,pre-pumping capabilities,polarization maintenance,and a low-noise nuclear magnetic resonance system.These advantages significantly reduce the preparation time and simplify polarized neutron experiments,making it suitable for various neutron beamlines in China,particularly those with a limited sample space.These characteristics establish it as a quasi-standardized system that plays a vital role in polarized neutron experiments,including those involving polarized neutron imaging,neutron reflection,the performance calibration of polarized neutron instruments,and the neutron optics parity and time reversal experiment.
文摘About this issue:Radar astronomy is a science that utilizes radar electromagnetic waves to study celestial bodies within and beyond the solar system,focusing mainly on planets,satellites and small bodies such as the Moon,Mars,Venus and Saturn.Through radar electromagnetic wave detection,we are able to gain an in-depth understanding of these celestial bodies'internal structures,composition,distribution of water resources,magnetic fields,atmospheres,and other physical properties.This is of great significance for human beings to find a habitable environment in the solar system.At present,the observation methods of radar astronomy mainly rely on ground-based radio telescopes that actively emit electromagnetic waves.In recent years,with the continuous advancement of international deep space exploration,in-situ radar detection technology has gradually become an indispensable new tool for lunar and planetary radar astronomical observations.For example,China's Chang'e3,4,5 and 6 missions,as well as the Tianwen-1 mission to Mars and the United States'Perseverance rover,are equipped with radar payloads.These deep space exploration missions have expanded radar astronomy techniques to lunar and planetary surface observations,greatly enriching and promoting the scientific content and development of radar astronomy.For this reason,the editorial office invited Dr.Chunyu Ding from Shenzhen University and Dr.Yan Su from the National Astronomical Observatories,Chinese Academy of Sciences to co edit a special issue of radar astronomy.
基金supported by the Synergetic Extreme-Condition User Facility(SECUF)the National Key R&D Program of China(Grant Nos.2021YFA1400100,2020YFA0308800,and 2022YFA1604200)+2 种基金the National Natural Science Foundation of China(Grant Nos.12234011,92250305,52388201,11725418,and 11427903)supported by the China Postdoctoral Science Foundation(Grant Nos.2022M721886 and BX20230187)the Shuimu Tsinghua Scholar Program。
文摘Capturing ultrafast dynamics over a large momentum space is critical for revealing the relationship between the electronic and structural modulations in quantum materials.Here,by performing time-and angle-resolved photoemission spectroscopy measurements at the Synergetic Extreme Condition User Facility(SECUF)equipped with an extreme ultraviolet light source,we reveal the ultrafast dynamics of a charge-density wave(CDW)material,1T-TiSe_(2),upon photoexcitation.Pump-induced CDW melting is revealed from two aspects:gap closing of the CDW at the Brillouin zone(BZ)center and weakening of the CDW folded band at the BZ boundary.By comparing the transient electronic structure and spectral weight over a large momentum space,we further reveal the carrier redistribution involving the excitation of electrons from theГpoint to the M point.This study provides a comprehensive picture of the physics and ultrafast dynamics of a CDW material across the entire BZ.
文摘The evolution of information technology has propelled the advancement of sensors into a new era,referred to as Sensors 4.0^([1]).This era is characterized by the integration of key technological developments,including the internet of things(IoT),Industry 4.0,big data,artificial intelligence(AI),robotics,and digital health.These innovations necessitate that sensors become increasingly interconnected and intelligent.The concept of"everything is connected"demands that sensors undertake a broader and more complex range of tasks,a challenge that conventional,bulky devices are ill-equipped to address.
基金supported in part by the National Natural Science Foundation of China(62225306,U2141235,52188102).
文摘Dear Editor,Active magnetic bearings(AMBs)are of considerable interest and significance in smart manufacturing due to their zero-friction and adaptivity to noncontact rotor rotations.This paper proposes an active levitation control algorithm based on adaptive sliding mode control(ASMC)equipped with linear extended state observer(LESO).Sufficient conditions are derived to guarantee the asymptotical stability of the associated closed-loop system.Experiments are conducted on a real AMB-rotor platform to demonstrate the effectiveness and superiority of the proposed algorithm.
文摘Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection.
基金supported in part by Natural Science Foundation of Jiangsu Province under Grant BK20230255Natural Science Foundation of Shandong Province under Grant ZR2023QE281.
文摘The multi-terminal direct current(DC)grid has extinctive superiorities over the traditional alternating current system in integrating large-scale renewable energy.Both the DC circuit breaker(DCCB)and the current flow controller(CFC)are demanded to ensure the multiterminal DC grid to operates reliably and flexibly.However,since the CFC and the DCCB are all based on fully controlled semiconductor switches(e.g.,insulated gate bipolar transistor,integrated gate commutated thyristor,etc.),their separation configuration in the multiterminal DC grid will lead to unaffordable implementation costs and conduction power losses.To solve these problems,integrated equipment with both current flow control and fault isolation abilities is proposed,which shares the expensive and duplicated components of CFCs and DCCBs among adjacent lines.In addition,the complicated coordination control of CFCs and DCCBs can be avoided by adopting the integrated equipment in themultiterminal DC grid.In order to examine the current flow control and fault isolation abilities of the integrated equipment,the simulation model of a specific meshed four-terminal DC grid is constructed in the PSCAD/EMTDC software.Finally,the comparison between the integrated equipment and the separate solution is presented a specific result or conclusion needs to be added to the abstract.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFC2204203)the National Natural Science Foundation of China(Grant No.52305107)。
文摘Precision actuation is a foundational technology in high-end equipment domains,where stroke,velocity,and accuracy are critical for processing and/or detection quality,precision in spacecraft flight trajectories,and accuracy in weapon system strikes.Piezoelectric actuators(PEAs),known for their nanometer-level precision,flexible stroke,resistance to electromagnetic interference,and scalable structure,have been widely adopted across various fields.Therefore,this study focuses on extreme scenarios involving ultra-high precision(micrometer and beyond),minuscule scales,and highly complex operational conditions.It provides a comprehensive overview of the types,working principles,advantages,and disadvantages of PEAs,along with their potential applications in piezo-actuated smart mechatronic systems(PSMSs).To address the demands of extreme scenarios in high-end equipment fields,we have identified five representative application areas:positioning and alignment,biomedical device configuration,advanced manufacturing and processing,vibration mitigation,micro robot system.Each area is further divided into specific subcategories,where we explore the underlying relationships,mechanisms,representative schemes,and characteristics.Finally,we discuss the challenges and future development trends related to PEAs and PSMSs.This work aims to showcase the latest advancements in the application of PEAs and provide valuable guidance for researchers in this field.
