Multiple functional metasurfaces with high information capacity have attracted considerable attention from researchers.This study proposes a 2-bit tunable spin-decoupled coded metasurface designed for the terahertz ba...Multiple functional metasurfaces with high information capacity have attracted considerable attention from researchers.This study proposes a 2-bit tunable spin-decoupled coded metasurface designed for the terahertz band,which utilizes the tunable properties of Dirac semimetals(DSM)to create a novel multilayer structure.By incorporating both geometric and propagating phases into the metasurface design,we can effectively control the electromagnetic wave.When the Fermi level(EF)of the DSM is set at 6 meV,the electromagnetic wave is manipulated by the gold patch embedded in the DSM film,operating at a frequency of 1.3 THz.When the EF of the DSM is set at 80 meV,the electromagnetic wave is manipulated by the DSM patch,operating at a frequency of 1.4 THz.Both modes enable independent control of beam splitting under left-rotating circularly polarized(LCP)and rightrotating circularly polarized(RCP)wave excitation,resulting in the generation of vortex beams with distinct orbital angular momentum(OAM)modes.The findings of this study hold significant potential for enhancing information capacity and polarization multiplexing techniques in wireless communications.展开更多
Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile ...Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile sensors,accurately decoupling signals—specifically separating forces from directional orientation and temperature—remains a challenge thus resulting in failure to meet the advanced application requirements of robots.This study proposes,F3T,a multilayer soft sensor unit designed to achieve isolated measurements and mathematical decoupling of normal pressure,omnidirectional tangential forces,and temperature.We developed a circular coaxial magnetic film featuring a floating mount multilayer capacitor that facilitated the physical decoupling of normal and tangential forces in all directions.Additionally,we incorporated an ion gel-based temperature-sensing film into the tactile sensor.The proposed sensor was resilient to external pressures and deformations,and could measure temperature and significantly eliminate capacitor errors induced by environmental temperature changes.In conclusion,our novel design allowed for the decoupled measurement of multiple signals,laying the foundation for advancements in high-level robotic motion control,autonomous decision-making,and task planning.展开更多
The elimination of the vertical tail in tailless aircraft results in a significant decrease in heading static stability,causing substantial coupling among the three control channels.In addition,in specific operational...The elimination of the vertical tail in tailless aircraft results in a significant decrease in heading static stability,causing substantial coupling among the three control channels.In addition,in specific operational scenarios,the tailless aircraft is prone to electromagnetic interference,leading to the generation of high-frequency noise and consequently compromising their control performance.To address these issues,a decoupling control method based on a fractional-order error extended state observer(FOEESO)is proposed.A nonlinear model of a tailless aircraft with thrust vectoring capabilities is first developed.The decoupling control design for the three control channels is then implemented using FOEESO,with the asymptotic convergence conditions outlined.The proposed method is evaluated through simulations and compared to coupled control and linear extended state observer(LESO)techniques.Numerical simulations demonstrate that the FOEESO-based control methodology achieves effective decoupling,exhibiting 6.9%and 11.7%reductions in integral absolute error(IAE)relative to LESO under nominal operational conditions and critical fault scenarios,respectively.These improvements thereby highlight FOEESO’s capability to enhance closed-loop stability and tracking precision in tailless aircraft control systems.展开更多
Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among th...Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among the input axes,and coupled linear and angular motions of the end effector.This paper presents an inverse hysteresis-coupling hybrid model to account for such hysteresis and couplings.First,a specially designed kinematic chain is adopted to transfer the pose of the end effector into the linear motions at three prismatic joints.Second,an inverse hysteresis-coupling hybrid model is developed to linearize and decouple the system via a multilayer feedforward neural network.A fractional-order PID controller is also integrated to improve the motion accuracy of the overall system.Experimental results demonstrate that the proposed method can accurately control the motion of the end effector with improved accuracy and robustness.展开更多
Dynamical decoupling(DD),usually implemented by sophisticated sequences of instantaneous control pulses,is a well-established quantum control technique for quantum information and quantum sensing.In practice,the pulse...Dynamical decoupling(DD),usually implemented by sophisticated sequences of instantaneous control pulses,is a well-established quantum control technique for quantum information and quantum sensing.In practice,the pulses are inevitably imperfect with many systematic errors that may influence the performances of DD.In particular,Rabi error and detuning are primary systemic errors arising from finite pulse duration,incorrect time control,and frequency instability.Here,we propose a phase-modulated DD with staggered global phases for the basic units of the pulse sequences to suppress these systemic errors.By varying the global phases appended to the pulses in the dynamical decoupling unit alternatively with 0 orπ,our protocol can significantly reduce the influences of Rabi error and detuning.Our protocol is general and can be combined with the most existing DD sequences such as universal DD,knill DD,XY,etc.As an example,we further apply our method to quantum lock-in detection for measuring time-dependent alternating signals.Our study paves the way for a simple and feasible way to realize robust dynamical decoupling sequences,which can be applicable for various quantum sensing scenarios.展开更多
Exploring the factors driving the decoupling of China’s sulfur dioxide(SO_(2))emissions from economic growth(DEI)is crucial for achieving sustainable development.By analyzing the decoupling indicators and driving fac...Exploring the factors driving the decoupling of China’s sulfur dioxide(SO_(2))emissions from economic growth(DEI)is crucial for achieving sustainable development.By analyzing the decoupling indicators and driving factors at both the generation and treatment stages of SO_(2),more effective targeted mitigation strategies can be developed.We employ the Tapio decoupling model and propose a two-stage method to examine the decoupling issues related to SO_(2).Our findings indicate that:①DEI shows a steady and significant improvement,with SO_(2)emission intensity identified as the primary driver.②for the decoupling of economic growth and SO_(2)generation,energy scale serves as the largest stimulator,while the effect of energy intensity changes from negative to positive,and pollution intensity is first positive and then negative.③For the decoupling of SO_(2)generation and SO_(2)removal,treatment efficiency leads as the largest promoter,followed by treatment intensity.Based on these results,this study recommends that China focuses more on enhancing clean energy utilization and the effectiveness of treatment processes.展开更多
The progress from intelligent interactions requires electronic skin(E-skin)to shift from single-functional perception to multisensory capabilities.However,the intuitive and interference-free reading of multiple sensor...The progress from intelligent interactions requires electronic skin(E-skin)to shift from single-functional perception to multisensory capabilities.However,the intuitive and interference-free reading of multiple sensory signals without involving complex algorithms is a critical challenge.Herein,we propose a flexible multisensory E-skin by developing a highly homogeneous dispersion of BaTiO_(3)nanoparticles in polydimethylsiloxane dielectric layer.The E-skin is sensitive to externally applied pressure as well as temperature and can distinguish dual synergetic stimuli by the time decoupling effect.The pressure and temperature perception was achieved in an individual device,which greatly reduced the structural complexity compared with multifunctional integrated devices.The sensitivity of E-skin for pressure detection is as high as 0.0724 kPa^(−1)and the detection range reaches as wide as 15.625-10 MPa.The sensitivity to temperature detection is as high as−1.34℃^(−1)and the detection range reaches 20-200℃.More importantly,by equipping with a multilayer neural network,the evolution from tactile perception to advanced intelligent tactile cognition is demonstrated.展开更多
Quantifying material use in infrastructure development and analyzing its relationship with economic growth is essential for enhancing resource efficiency and steering regional resource management toward sustainable de...Quantifying material use in infrastructure development and analyzing its relationship with economic growth is essential for enhancing resource efficiency and steering regional resource management toward sustainable development.This study systematically assessed infrastructure related material use in 30 provinces,autonomous regions,and municipalities in China during 1978-2022.The result indicated that material stock has experienced significant growth,increasing from 16.91×10^(9)t in 1978 to 103.60×10^(9)t in 2022,with an average annual growth rate of 4.20%.However,from 1978 to 2015,material input followed a strong upward trend but saturated after 2015.At the national level,material input peaked in 2015,after which it began to decline.The central region reached its peak earlier in 2013,while the eastern and western regions peaked in 2015.Using a decoupling analysis framework,this study revealed that nationally,the elasticity value between material stock and gross domestic product(GDP)remained near or above 1.0,reflecting continued reliance on stock accumulation.Regionally,the elasticity value between material stock and GDP has increased in the central and western regions during 1978-2022,whereas elasticity value between material stock and GDP in the eastern region showed a slower growth rate but still struggled to achieve absolute decoupling.Moreover,the elasticity value between material input and GDP has declined at the national level,presenting a relative decoupling,with some regions already achieving absolute decoupling.The eastern region was closer to absolute decoupling,while the central and western regions,though still intensive in material input,exhibited faster declines in elasticity.Accelerating the transition from linear to circular economy is an essential step for China to achieve absolute decoupling and long-term sustainability.Finally,this research recommends promoting the adoption of renewable energy,driving industrial upgrading,implementing compact urban design,and extending the lifespan of infrastructure to reduce material dependency and achieve sustainable infrastructure transformation at the national level.展开更多
Dual-atom catalysts(DACs),a natural extension of single-atom catalysts(SACs),have emerged as a prominent focal point in the field of heterogeneous catalysis,particularly in the context of chemical and energy conversio...Dual-atom catalysts(DACs),a natural extension of single-atom catalysts(SACs),have emerged as a prominent focal point in the field of heterogeneous catalysis,particularly in the context of chemical and energy conversion processes.Despite the fact that the catalytic activity of DACs is significantly modulated by the electronic structure of the catalyst,understanding how electron spin states are affected by variations in topology and geometric structure remains challenging and relatively unexplored.Herein,we propose the rational design of stable DACs composed of two iron atoms anchored on pristine graphdiyne(GDY),Fe_(2)-GDYn.A comprehensive and systematic investigation was carried out to elucidate the electronic configuration and spin states involved in the deliberate convergence towards the magnetic ground state,with the aim of uncovering the structure-spin relationship.Through an in-depth analysis of spin populations,electronic localization/delocalization,and the chemical bonding characteristics of the central metal atoms and the GDY skeleton,it was revealed that the spin coupling between the two iron atoms is preponderantly dictated by adjacent short-range Fe-Fe interactions.Conversely,spin decoupling can be attributed to the long-rangeπ-bond component within the linkage.Moreover,geometric and chemical bonding asymmetries were found to induce orbital and spin splitting in iron atoms possessing an electronic configuration of d8.These findings provide important insights into the relationship between topology and spin,thereby presenting novel strategies for the rational design of spin-manipulated DACs.展开更多
A control strategy of repetitive control without inductorance decoupling was proposed to address the problem of high total harmonic distortion(THD)rate of the network-side current caused by the reduced stability of th...A control strategy of repetitive control without inductorance decoupling was proposed to address the problem of high total harmonic distortion(THD)rate of the network-side current caused by the reduced stability of the rectifier module of the DC charging pile under weak grid as well as the dead zone and nonlinearity of switching devices during charging.Firstly,the parallel repetitive control was constructed in the inner current loop,and the proportional-integral(PI)+repetitive controller based on parallel structure was designed.For system compensation,a second-order low-pass filter was selected to correct the system,and the network-side current harmonics were actively suppressed without increasing the filtering device,which effectively improves the quality of grid-connected current.Secondly,based on the synthetic vector method,the controller parameters were designed to realize the elimination of main pole by establishing two synchronous rotation coordinate system vector differential equations,so as to realize the inductanceless decoupling to cope with the influence of network-side inductance fluctuation on the stability of the control system under weak grid.By theoretical analysis and simulation,the proposed control strategy was embedded into the self-developed digital signal processor for the rectifier module of DC charging pile,simulated dynamic and steady-state operation experiments were conducted,and comparative analysis was performed to prove the feasibility of the proposed control strategy.展开更多
In this paper, we apply the two-time Green's function method, and provide a simple way to study themagnetic properties of one-dimensional spin-(S, s) Heisenberg ferromagnets.The magnetic susceptibility and correla...In this paper, we apply the two-time Green's function method, and provide a simple way to study themagnetic properties of one-dimensional spin-(S, s) Heisenberg ferromagnets.The magnetic susceptibility and correlationfunctions are obtained by using the Tyablikov decoupling approximation.Our results show that the magnetic susceptibilityand correlation length are a monotonically decreasing function of temperature regardless of the mixed spins.It isfound that in the case of S = s, our results of one-dimensional mixed-spin model is reduced to be those of the isotropicferromagnetic Heisenberg chain in the whole temperature region.Our results for the susceptibility are in agreement withthose obtained by other theoretical approaches.展开更多
Hyperpolarization of nuclear spins is crucial for advancing nuclear magnetic resonance and quantum information technologies,as nuclear spins typically exhibit extremely low polarization at room temperature due to thei...Hyperpolarization of nuclear spins is crucial for advancing nuclear magnetic resonance and quantum information technologies,as nuclear spins typically exhibit extremely low polarization at room temperature due to their small gyromagnetic ratios.A promising approach to achieving high nuclear spin polarization is transferring the polarization of electrons to nuclear spins.The nitrogen-vacancy(NV)center in diamond has emerged as a highly effective medium for this purpose,and various hyperpolarization protocols have been developed.Among these,the pulsed polarization(PulsePol)method has been extensively studied due to its robustness against static energy shifts of the electron spin.In this work,we present a novel polarization protocol and uncover a family of magic sequences for hyperpolarizing nuclear spins,with PulsePol emerging as a special case of our general approach.Notably,we demonstrate that some of these magic sequences exhibit significantly greater robustness compared to the PulsePol protocol in the presence of finite half𝜋pulse duration of the protocol,Rabi and detuning errors.This enhanced robustness positions our protocol as a more suitable candidate for hyper-polarizing nuclear spins species with large gyromagnetic ratios and also ensures better compatibility with high-efficiency readout techniques at high magnetic fields.Additionally,the generality of our protocol allows for its direct application to other solid-state quantum systems beyond the NV center.展开更多
The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges be...The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges between 0.2 and 0.4.This enhancement prompts a critical question:to what extent can quantum wells(QWs)be strained while still preserving the fundamental QSHI phase?In this study,we demonstrate the controlled molecular beam epitaxial growth of highly strained-layer QWs with an indium composition of x=0.5.These structures possess a substantial compressive strain within the In_(0.5)Ga_(0.5)Sb QW.Detailed crystal structure analyses confirm the exceptional quality of the resulting epitaxial films,indicating coherent lattice structures and the absence of visible dislocations.Transport measurements further reveal that the QSHI phase in InAs/In_(0.5)Ga_(0.5)Sb QWs is robust and protected by time-reversal symmetry.Notably,the edge states in these systems exhibit giant magnetoresistance when subjected to a modest perpendicular magnetic field.This behavior is in agreement with the𝑍2 topological property predicted by the Bernevig–Hughes–Zhang model,confirming the preservation of topologically protected edge transport in the presence of enhanced bulk strain.展开更多
Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emissi...Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects,thereby posing a significant challenge to their versatile cooling applicability.Herein,we present a bicomponent blow spinning strategy for the production of scalable,ultra-flexible,and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter.The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area,thereby achieving a competitive solar reflectivity of 98.7%on its outer surface.Additionally,the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces:The outer surface demonstrates a high mid-infrared emission,whereas the inner surface shows a broad infrared absorptivity,facilitating radiative heat exchange with underlying self-heated objects.Consequently,this textile demonstrates multi-scenario radiative cooling capabilities,enabling versatile outdoor cooling for unheated objects by 7.8℃ and self-heated objects by 13.6℃,compared to commercial sunshade fabrics.展开更多
Although intermediate temperature solid oxide fuel cells(IT-SOFCs)show great potential to address energy conversion challenges,the sluggish oxygen reduction reaction(ORR)kinetics of cathode materials has severely hind...Although intermediate temperature solid oxide fuel cells(IT-SOFCs)show great potential to address energy conversion challenges,the sluggish oxygen reduction reaction(ORR)kinetics of cathode materials has severely hindered extended applications.Herein,we have demonstrated that Bi^(3+)doping on the A-site synergistically regulates the phase transition and electron spin state in La_(0.3)Bi_(0.3)Ca_(0.4)FeO_(3-δ)(LBCF3)for improved performance.An orthorhombic to cubic phase transition occurred with Bi^(3+)doping increases oxygen vacancy concentration and thus increases oxygen ion migration capacity.Simultaneously,the change of Fe from low to medium electron spin state strengths O_(2)adsorption and improves catalytic performances.Consequently,a peak power density improvement up to 48%(from 1.21 to 1.79 W·cm^(-2))at 800℃ is realized in the anodesupported single cell using LBCF3 as cathode,which remains stable for over 270 h at 750℃.展开更多
One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three ...One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism＇s decoupling characteristics, the mechanism＇s kinematics analysis is solved, and the mechanism＇s direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism＇s dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism＇s control strategy, design, path planning etc.展开更多
Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling ...Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that （i） the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse ＂N＂ in temporal changes. （ii） Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse ＂V＂ change. （iii） The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod.展开更多
Use stable inversion to accomplish precise decoupling tracking of airspeed and altitude for conventional takeoff and landing of unmanned aerial vehicles (UAVs) is in essence a non-minimum phase output tracking problem...Use stable inversion to accomplish precise decoupling tracking of airspeed and altitude for conventional takeoff and landing of unmanned aerial vehicles (UAVs) is in essence a non-minimum phase output tracking problem. The main contribution of this article is that a new method to calculate the causal solution of stable inversion is proposed by introducing a well defined perturbed signal to the system’s unstable internal dynamics. It is helpful to overcome the pitfalls resulting from non-causality in existin...展开更多
Low-carbon economic development is a strategy that is emerging in response to global climate change. Being the third-largest energy base in the world, Central Asia should adopt rational and efficient energy utilizatio...Low-carbon economic development is a strategy that is emerging in response to global climate change. Being the third-largest energy base in the world, Central Asia should adopt rational and efficient energy utilization to achieve the sustainable economic development. In this study, the logarithmic mean Divisia index(LMDI) decomposition method was used to explore the influence factors of CO2 emissions in Central Asia(including Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan and Turkmenistan) during the period 1992–2014. Moreover, decoupling elasticity and decoupling index based on the LMDI decomposition results were employed to explore the relationship between economic growth and CO2 emissions during the study period. Our results show that the total CO2 emissions decreased during the period 1992–1998, influenced by the collapse of the Soviet Union in 1991 and the subsequent financial crisis. After 1998, the total CO2 emissions started to increase slowly along with the economic growth after the market economic reform. Energy-related CO2 emissions increased in Central Asia, mainly driven by economic activity effect and population effect, while energy intensity effect and energy carbon structure effect were the primary factors inhibiting CO2 emissions. The contribution percentages of these four factors(economic activity effect, population effect, energy intensity effect and energy carbon structure effect) to the total CO2 emissions were 11.80%, 39.08%, –44.82% and –4.32%, respectively, during the study period. Kazakhstan, Uzbekistan and Turkmenistan released great quantities of CO2 with the annual average emissions of 189.69×106, 45.55×106 and 115.38×106 t, respectively. In fact, their economic developments depended on high-carbon energies. The decoupling indices clarified the relationship between CO2 emissions and economic growth, highlighting the occurrence of a ’’weak decoupling’’ between these two variables in Central Asia. In conclusion, our results indicate that CO2 emissions are still not completely decoupled from economic growth in Central Asia. Based on these results, we suggest four key policy suggestions in this paper to help Central Asia to reduce CO2 emissions and build a resource-conserving and environment-friendly society.展开更多
文摘Multiple functional metasurfaces with high information capacity have attracted considerable attention from researchers.This study proposes a 2-bit tunable spin-decoupled coded metasurface designed for the terahertz band,which utilizes the tunable properties of Dirac semimetals(DSM)to create a novel multilayer structure.By incorporating both geometric and propagating phases into the metasurface design,we can effectively control the electromagnetic wave.When the Fermi level(EF)of the DSM is set at 6 meV,the electromagnetic wave is manipulated by the gold patch embedded in the DSM film,operating at a frequency of 1.3 THz.When the EF of the DSM is set at 80 meV,the electromagnetic wave is manipulated by the DSM patch,operating at a frequency of 1.4 THz.Both modes enable independent control of beam splitting under left-rotating circularly polarized(LCP)and rightrotating circularly polarized(RCP)wave excitation,resulting in the generation of vortex beams with distinct orbital angular momentum(OAM)modes.The findings of this study hold significant potential for enhancing information capacity and polarization multiplexing techniques in wireless communications.
基金support by Hong Kong RGC General Research Fund(16217824,16213825,16203923,and 16217824)National Natural Science Foundation of China(N_HKUST638/23)+1 种基金Research Grants Council Joint Research Scheme(62361166630)Guangdong Basic and Applied Basic Research Foundation(2023B1515130007).
文摘Human skin exhibits a remarkable capability to perceive contact forces and environmental temperatures,providing complex information that is essential for its subtle control.Despite recent advancements in soft tactile sensors,accurately decoupling signals—specifically separating forces from directional orientation and temperature—remains a challenge thus resulting in failure to meet the advanced application requirements of robots.This study proposes,F3T,a multilayer soft sensor unit designed to achieve isolated measurements and mathematical decoupling of normal pressure,omnidirectional tangential forces,and temperature.We developed a circular coaxial magnetic film featuring a floating mount multilayer capacitor that facilitated the physical decoupling of normal and tangential forces in all directions.Additionally,we incorporated an ion gel-based temperature-sensing film into the tactile sensor.The proposed sensor was resilient to external pressures and deformations,and could measure temperature and significantly eliminate capacitor errors induced by environmental temperature changes.In conclusion,our novel design allowed for the decoupled measurement of multiple signals,laying the foundation for advancements in high-level robotic motion control,autonomous decision-making,and task planning.
文摘The elimination of the vertical tail in tailless aircraft results in a significant decrease in heading static stability,causing substantial coupling among the three control channels.In addition,in specific operational scenarios,the tailless aircraft is prone to electromagnetic interference,leading to the generation of high-frequency noise and consequently compromising their control performance.To address these issues,a decoupling control method based on a fractional-order error extended state observer(FOEESO)is proposed.A nonlinear model of a tailless aircraft with thrust vectoring capabilities is first developed.The decoupling control design for the three control channels is then implemented using FOEESO,with the asymptotic convergence conditions outlined.The proposed method is evaluated through simulations and compared to coupled control and linear extended state observer(LESO)techniques.Numerical simulations demonstrate that the FOEESO-based control methodology achieves effective decoupling,exhibiting 6.9%and 11.7%reductions in integral absolute error(IAE)relative to LESO under nominal operational conditions and critical fault scenarios,respectively.These improvements thereby highlight FOEESO’s capability to enhance closed-loop stability and tracking precision in tailless aircraft control systems.
基金supported in part by the Open Fund of State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment,Guangdong University of Technology(Grant No.JMDZ2021007)in part by the Guangdong International Cooperation Program of Science and Technology(Grant No.2022A0505050078).
文摘Planar positioning systems are widely utilized in micro and nano applications.The challenges in modeling and control of XYΘflexure-based mechanisms include hysteresis of the piezoelectric actuators,couplings among the input axes,and coupled linear and angular motions of the end effector.This paper presents an inverse hysteresis-coupling hybrid model to account for such hysteresis and couplings.First,a specially designed kinematic chain is adopted to transfer the pose of the end effector into the linear motions at three prismatic joints.Second,an inverse hysteresis-coupling hybrid model is developed to linearize and decouple the system via a multilayer feedforward neural network.A fractional-order PID controller is also integrated to improve the motion accuracy of the overall system.Experimental results demonstrate that the proposed method can accurately control the motion of the end effector with improved accuracy and robustness.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFA1404104)the National Natural Science Foundation of China(Grant Nos.92476201,12025509,12305022,and 12475029)+1 种基金the Key-Area Research and Development Program of Guangdong Province,China(Grant No.2019B030330001)Guangdong Provincial Quantum Science Strategic Initiative Fund(Grant Nos.GDZX2305006 and GDZX2405002)。
文摘Dynamical decoupling(DD),usually implemented by sophisticated sequences of instantaneous control pulses,is a well-established quantum control technique for quantum information and quantum sensing.In practice,the pulses are inevitably imperfect with many systematic errors that may influence the performances of DD.In particular,Rabi error and detuning are primary systemic errors arising from finite pulse duration,incorrect time control,and frequency instability.Here,we propose a phase-modulated DD with staggered global phases for the basic units of the pulse sequences to suppress these systemic errors.By varying the global phases appended to the pulses in the dynamical decoupling unit alternatively with 0 orπ,our protocol can significantly reduce the influences of Rabi error and detuning.Our protocol is general and can be combined with the most existing DD sequences such as universal DD,knill DD,XY,etc.As an example,we further apply our method to quantum lock-in detection for measuring time-dependent alternating signals.Our study paves the way for a simple and feasible way to realize robust dynamical decoupling sequences,which can be applicable for various quantum sensing scenarios.
基金the National Natural Science Foundation of China[Grant No.52270183].
文摘Exploring the factors driving the decoupling of China’s sulfur dioxide(SO_(2))emissions from economic growth(DEI)is crucial for achieving sustainable development.By analyzing the decoupling indicators and driving factors at both the generation and treatment stages of SO_(2),more effective targeted mitigation strategies can be developed.We employ the Tapio decoupling model and propose a two-stage method to examine the decoupling issues related to SO_(2).Our findings indicate that:①DEI shows a steady and significant improvement,with SO_(2)emission intensity identified as the primary driver.②for the decoupling of economic growth and SO_(2)generation,energy scale serves as the largest stimulator,while the effect of energy intensity changes from negative to positive,and pollution intensity is first positive and then negative.③For the decoupling of SO_(2)generation and SO_(2)removal,treatment efficiency leads as the largest promoter,followed by treatment intensity.Based on these results,this study recommends that China focuses more on enhancing clean energy utilization and the effectiveness of treatment processes.
基金Ningbo Scientific and Technological Innovation 2025 Major Project,Grant/Award Number:2020Z022German Research Foundation(DFG)grants,Grant/Award Numbers:MA 5144/13-1,MA 5144/28-1+6 种基金the National Natural Science Foundation of China,Grant/Award Numbers:62204246,51931011,51971233,52127803,62174165the External Cooperation Program of Chinese Academy of Sciences,Grant/Award Numbers:174433KYSB20190038,174433KYSB20200013the Instrument Developing Project of the Chinese Academy of Sciences,Grant/Award Number:YJKYYQ20200030K.C.Wong Education Foundation,Grant/Award Number:GJTD-2020-11Chinese Academy of Sciences Youth Innovation Promotion Association,Grant/Award Number:2018334Zhejiang Provincial Key R&D Program,Grant/Award Numbers:2021C01183,2022C01032the National Natural Science Foundation of Zhejiang Province of China,Grant/Award Number:LQ23F040004.
文摘The progress from intelligent interactions requires electronic skin(E-skin)to shift from single-functional perception to multisensory capabilities.However,the intuitive and interference-free reading of multiple sensory signals without involving complex algorithms is a critical challenge.Herein,we propose a flexible multisensory E-skin by developing a highly homogeneous dispersion of BaTiO_(3)nanoparticles in polydimethylsiloxane dielectric layer.The E-skin is sensitive to externally applied pressure as well as temperature and can distinguish dual synergetic stimuli by the time decoupling effect.The pressure and temperature perception was achieved in an individual device,which greatly reduced the structural complexity compared with multifunctional integrated devices.The sensitivity of E-skin for pressure detection is as high as 0.0724 kPa^(−1)and the detection range reaches as wide as 15.625-10 MPa.The sensitivity to temperature detection is as high as−1.34℃^(−1)and the detection range reaches 20-200℃.More importantly,by equipping with a multilayer neural network,the evolution from tactile perception to advanced intelligent tactile cognition is demonstrated.
基金supported by the Shanghai Committee of Science and Technology Fund(22ZR1419300)the Academic Year 2025 Ritsumeikan Asia Pacific University Academic Research Subsidy(Grants-in-Aid Reapplication Type).
文摘Quantifying material use in infrastructure development and analyzing its relationship with economic growth is essential for enhancing resource efficiency and steering regional resource management toward sustainable development.This study systematically assessed infrastructure related material use in 30 provinces,autonomous regions,and municipalities in China during 1978-2022.The result indicated that material stock has experienced significant growth,increasing from 16.91×10^(9)t in 1978 to 103.60×10^(9)t in 2022,with an average annual growth rate of 4.20%.However,from 1978 to 2015,material input followed a strong upward trend but saturated after 2015.At the national level,material input peaked in 2015,after which it began to decline.The central region reached its peak earlier in 2013,while the eastern and western regions peaked in 2015.Using a decoupling analysis framework,this study revealed that nationally,the elasticity value between material stock and gross domestic product(GDP)remained near or above 1.0,reflecting continued reliance on stock accumulation.Regionally,the elasticity value between material stock and GDP has increased in the central and western regions during 1978-2022,whereas elasticity value between material stock and GDP in the eastern region showed a slower growth rate but still struggled to achieve absolute decoupling.Moreover,the elasticity value between material input and GDP has declined at the national level,presenting a relative decoupling,with some regions already achieving absolute decoupling.The eastern region was closer to absolute decoupling,while the central and western regions,though still intensive in material input,exhibited faster declines in elasticity.Accelerating the transition from linear to circular economy is an essential step for China to achieve absolute decoupling and long-term sustainability.Finally,this research recommends promoting the adoption of renewable energy,driving industrial upgrading,implementing compact urban design,and extending the lifespan of infrastructure to reduce material dependency and achieve sustainable infrastructure transformation at the national level.
文摘Dual-atom catalysts(DACs),a natural extension of single-atom catalysts(SACs),have emerged as a prominent focal point in the field of heterogeneous catalysis,particularly in the context of chemical and energy conversion processes.Despite the fact that the catalytic activity of DACs is significantly modulated by the electronic structure of the catalyst,understanding how electron spin states are affected by variations in topology and geometric structure remains challenging and relatively unexplored.Herein,we propose the rational design of stable DACs composed of two iron atoms anchored on pristine graphdiyne(GDY),Fe_(2)-GDYn.A comprehensive and systematic investigation was carried out to elucidate the electronic configuration and spin states involved in the deliberate convergence towards the magnetic ground state,with the aim of uncovering the structure-spin relationship.Through an in-depth analysis of spin populations,electronic localization/delocalization,and the chemical bonding characteristics of the central metal atoms and the GDY skeleton,it was revealed that the spin coupling between the two iron atoms is preponderantly dictated by adjacent short-range Fe-Fe interactions.Conversely,spin decoupling can be attributed to the long-rangeπ-bond component within the linkage.Moreover,geometric and chemical bonding asymmetries were found to induce orbital and spin splitting in iron atoms possessing an electronic configuration of d8.These findings provide important insights into the relationship between topology and spin,thereby presenting novel strategies for the rational design of spin-manipulated DACs.
基金supported by National Natural Science Foundation of China(No.61903291)Shaanxi Province Key R&D Program(No.2022GY-134)。
文摘A control strategy of repetitive control without inductorance decoupling was proposed to address the problem of high total harmonic distortion(THD)rate of the network-side current caused by the reduced stability of the rectifier module of the DC charging pile under weak grid as well as the dead zone and nonlinearity of switching devices during charging.Firstly,the parallel repetitive control was constructed in the inner current loop,and the proportional-integral(PI)+repetitive controller based on parallel structure was designed.For system compensation,a second-order low-pass filter was selected to correct the system,and the network-side current harmonics were actively suppressed without increasing the filtering device,which effectively improves the quality of grid-connected current.Secondly,based on the synthetic vector method,the controller parameters were designed to realize the elimination of main pole by establishing two synchronous rotation coordinate system vector differential equations,so as to realize the inductanceless decoupling to cope with the influence of network-side inductance fluctuation on the stability of the control system under weak grid.By theoretical analysis and simulation,the proposed control strategy was embedded into the self-developed digital signal processor for the rectifier module of DC charging pile,simulated dynamic and steady-state operation experiments were conducted,and comparative analysis was performed to prove the feasibility of the proposed control strategy.
基金Supported by the Natural Science Foundation of Guangdong Province under Grant No.8151009001000055
文摘In this paper, we apply the two-time Green's function method, and provide a simple way to study themagnetic properties of one-dimensional spin-(S, s) Heisenberg ferromagnets.The magnetic susceptibility and correlationfunctions are obtained by using the Tyablikov decoupling approximation.Our results show that the magnetic susceptibilityand correlation length are a monotonically decreasing function of temperature regardless of the mixed spins.It isfound that in the case of S = s, our results of one-dimensional mixed-spin model is reduced to be those of the isotropicferromagnetic Heisenberg chain in the whole temperature region.Our results for the susceptibility are in agreement withthose obtained by other theoretical approaches.
基金supported by the National Natural Science Foundation of China (Grant Nos.12475012,62461160263 for P.W.,and 62276171 for H.L.)Quantum Science and Technology-National Science and Technology Major Project of China (Project No.2023ZD0300600 for P.W.)+3 种基金Guangdong Provincial Quantum Science Strategic Initiative (Grant Nos.GDZX240-3009 and GDZX2303005 for P.W.)Guangdong Basic and Applied Basic Research Foundation (Grant No.2024-A1515011938 for H.L.)Shenzhen Fundamental ResearchGeneral Project (Grant No.JCYJ20240813141503005 for H.L.)the Talents Introduction Foundation of Beijing Normal University (Grant No.310432106 for P.W.)。
文摘Hyperpolarization of nuclear spins is crucial for advancing nuclear magnetic resonance and quantum information technologies,as nuclear spins typically exhibit extremely low polarization at room temperature due to their small gyromagnetic ratios.A promising approach to achieving high nuclear spin polarization is transferring the polarization of electrons to nuclear spins.The nitrogen-vacancy(NV)center in diamond has emerged as a highly effective medium for this purpose,and various hyperpolarization protocols have been developed.Among these,the pulsed polarization(PulsePol)method has been extensively studied due to its robustness against static energy shifts of the electron spin.In this work,we present a novel polarization protocol and uncover a family of magic sequences for hyperpolarizing nuclear spins,with PulsePol emerging as a special case of our general approach.Notably,we demonstrate that some of these magic sequences exhibit significantly greater robustness compared to the PulsePol protocol in the presence of finite half𝜋pulse duration of the protocol,Rabi and detuning errors.This enhanced robustness positions our protocol as a more suitable candidate for hyper-polarizing nuclear spins species with large gyromagnetic ratios and also ensures better compatibility with high-efficiency readout techniques at high magnetic fields.Additionally,the generality of our protocol allows for its direct application to other solid-state quantum systems beyond the NV center.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos.XDB28000000 and XDB0460000)the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2021ZD0302600)the National Key Research and Development Program of China(Grant No.2024YFA1409002)。
文摘The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges between 0.2 and 0.4.This enhancement prompts a critical question:to what extent can quantum wells(QWs)be strained while still preserving the fundamental QSHI phase?In this study,we demonstrate the controlled molecular beam epitaxial growth of highly strained-layer QWs with an indium composition of x=0.5.These structures possess a substantial compressive strain within the In_(0.5)Ga_(0.5)Sb QW.Detailed crystal structure analyses confirm the exceptional quality of the resulting epitaxial films,indicating coherent lattice structures and the absence of visible dislocations.Transport measurements further reveal that the QSHI phase in InAs/In_(0.5)Ga_(0.5)Sb QWs is robust and protected by time-reversal symmetry.Notably,the edge states in these systems exhibit giant magnetoresistance when subjected to a modest perpendicular magnetic field.This behavior is in agreement with the𝑍2 topological property predicted by the Bernevig–Hughes–Zhang model,confirming the preservation of topologically protected edge transport in the presence of enhanced bulk strain.
基金financial support from the National Natural Science Foundation of China(Grant No.52273067,52233006)the Fundamental Research Funds for the Central Universities(Grant No.2232023A-03)+3 种基金the Shuguang Program of Shanghai Education Development Foundation and Shanghai Municipal Education Commission(Grant No.23SG29)the Natural Science Foundation of Shanghai(Grant No.24ZR1402400)the Shanghai Scientific and Technological Innovation Project(Grant No.24520713000)Innovation Program of Shanghai Municipal Education Commission(Grant No.2021-01-07-00-03-E00108).
文摘Radiative cooling textiles with spectrally selective surfaces offer a promising energy-efficient approach for sub-ambient cooling of outdoor objects and individuals.However,the spectrally selective mid-infrared emission of these textiles significantly hinders their efficient radiative heat exchange with self-heated objects,thereby posing a significant challenge to their versatile cooling applicability.Herein,we present a bicomponent blow spinning strategy for the production of scalable,ultra-flexible,and healable textiles featuring a tailored dual gradient in both chemical composition and fiber diameter.The gradient in the fiber diameter of this textile introduces a hierarchically porous structure across the sunlight incident area,thereby achieving a competitive solar reflectivity of 98.7%on its outer surface.Additionally,the gradient in the chemical composition of this textile contributes to the formation of Janus infrared-absorbing surfaces:The outer surface demonstrates a high mid-infrared emission,whereas the inner surface shows a broad infrared absorptivity,facilitating radiative heat exchange with underlying self-heated objects.Consequently,this textile demonstrates multi-scenario radiative cooling capabilities,enabling versatile outdoor cooling for unheated objects by 7.8℃ and self-heated objects by 13.6℃,compared to commercial sunshade fabrics.
基金supported by the Xinjiang Autonomous Region Key Research Project(No.2022D01D31)the Start-up Grant of Xinjiang University,the Basic Research Fund for Autonomous Region Universities(No.XJEDU2024P015)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(No.2022D01C668).
文摘Although intermediate temperature solid oxide fuel cells(IT-SOFCs)show great potential to address energy conversion challenges,the sluggish oxygen reduction reaction(ORR)kinetics of cathode materials has severely hindered extended applications.Herein,we have demonstrated that Bi^(3+)doping on the A-site synergistically regulates the phase transition and electron spin state in La_(0.3)Bi_(0.3)Ca_(0.4)FeO_(3-δ)(LBCF3)for improved performance.An orthorhombic to cubic phase transition occurred with Bi^(3+)doping increases oxygen vacancy concentration and thus increases oxygen ion migration capacity.Simultaneously,the change of Fe from low to medium electron spin state strengths O_(2)adsorption and improves catalytic performances.Consequently,a peak power density improvement up to 48%(from 1.21 to 1.79 W·cm^(-2))at 800℃ is realized in the anodesupported single cell using LBCF3 as cathode,which remains stable for over 270 h at 750℃.
基金The National High Technology Research and Development Program of China(863Program)(No.2006AA040202)
文摘One kind of movable-pair analysis method is adopted to analyze the configuration of a 3-7R （revolute-pair） parallel decoupling mechanism, and the mechanism＇s characteristics are summarized. The mechanism has three orthogonal distributional branch-chains, and all movable pairs are rotational joints. The movable platform of the mechanism has x, y, z translational decoupling directions. Furthermore, in order to verify the mechanism＇s decoupling characteristics, the mechanism＇s kinematics analysis is solved, and the mechanism＇s direct/inverse kinematics model, input/output velocities and accelerations are deduced, which confirm its decoupling movement characteristics. Finally, one kind of mechanism link decomposed-integrated approach is adopted, and the mechanism＇s dynamics model is completed with the Lagrange method, which also proves its decoupling force characteristics. All of these works provide significant theory for the further study of the mechanism＇s control strategy, design, path planning etc.
基金Supported by Scientific Research Foundation of Yunnan Provincial Department of Education(2015J088)~~
文摘Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that （i） the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse ＂N＂ in temporal changes. （ii） Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse ＂V＂ change. （iii） The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod.
基金Weapons Equipment Pre-research Foundation of China (9140 A25040106HK0118)
文摘Use stable inversion to accomplish precise decoupling tracking of airspeed and altitude for conventional takeoff and landing of unmanned aerial vehicles (UAVs) is in essence a non-minimum phase output tracking problem. The main contribution of this article is that a new method to calculate the causal solution of stable inversion is proposed by introducing a well defined perturbed signal to the system’s unstable internal dynamics. It is helpful to overcome the pitfalls resulting from non-causality in existin...
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA19030204)the West Light Foundation of the Chinese Academy of Sciences (2015-XBQN-17)
文摘Low-carbon economic development is a strategy that is emerging in response to global climate change. Being the third-largest energy base in the world, Central Asia should adopt rational and efficient energy utilization to achieve the sustainable economic development. In this study, the logarithmic mean Divisia index(LMDI) decomposition method was used to explore the influence factors of CO2 emissions in Central Asia(including Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan and Turkmenistan) during the period 1992–2014. Moreover, decoupling elasticity and decoupling index based on the LMDI decomposition results were employed to explore the relationship between economic growth and CO2 emissions during the study period. Our results show that the total CO2 emissions decreased during the period 1992–1998, influenced by the collapse of the Soviet Union in 1991 and the subsequent financial crisis. After 1998, the total CO2 emissions started to increase slowly along with the economic growth after the market economic reform. Energy-related CO2 emissions increased in Central Asia, mainly driven by economic activity effect and population effect, while energy intensity effect and energy carbon structure effect were the primary factors inhibiting CO2 emissions. The contribution percentages of these four factors(economic activity effect, population effect, energy intensity effect and energy carbon structure effect) to the total CO2 emissions were 11.80%, 39.08%, –44.82% and –4.32%, respectively, during the study period. Kazakhstan, Uzbekistan and Turkmenistan released great quantities of CO2 with the annual average emissions of 189.69×106, 45.55×106 and 115.38×106 t, respectively. In fact, their economic developments depended on high-carbon energies. The decoupling indices clarified the relationship between CO2 emissions and economic growth, highlighting the occurrence of a ’’weak decoupling’’ between these two variables in Central Asia. In conclusion, our results indicate that CO2 emissions are still not completely decoupled from economic growth in Central Asia. Based on these results, we suggest four key policy suggestions in this paper to help Central Asia to reduce CO2 emissions and build a resource-conserving and environment-friendly society.
