High-throughput transcriptomics has evolved from bulk RNA-seq to single-cell and spatial profiling,yet its clinical translation still depends on effective integration across diverse omics and data modalities.Emerging ...High-throughput transcriptomics has evolved from bulk RNA-seq to single-cell and spatial profiling,yet its clinical translation still depends on effective integration across diverse omics and data modalities.Emerging foundation models and multimodal learning frameworks are enabling scalable and transferable representations of cellular states,while advances in interpretability and real-world data integration are bridging the gap between discovery and clinical application.This paper outlines a concise roadmap for AI-driven,transcriptome-centered multi-omics integration in precision medicine(Figure 1).展开更多
In response to the capabilities presented by the High-Intensity Heavy Ion Accelerator Facility(HIAF) and the Accelerator-Driven Subcritical System(Ci ADS), as well as the proposed Chinese Advanced Nuclear Physics Rese...In response to the capabilities presented by the High-Intensity Heavy Ion Accelerator Facility(HIAF) and the Accelerator-Driven Subcritical System(Ci ADS), as well as the proposed Chinese Advanced Nuclear Physics Research Facility(CNUF), we are assembling a consortium of experts in relevant disciplines, both domestically and internationally,to delineate high-precision physics experiments that leverage the state-of-the-art research environment afforded by CNUF.Our focus encompasses six primary domains of inquiry: hadron physics—including endeavors such as the super eta factory and investigations into light hadron structures;muon physics;neutrino physics;neutron physics;the testing of fundamental symmetries;and the exploration of quantum effects within nuclear physics, along with the utilization of vortex accelerators.We aim to foster a well-rounded portfolio of large, medium, and small-scale projects, thus unlocking new scientific avenues and optimizing the potential of the Huizhou large scientific facility. The aspiration for international leadership in scientific research will be a guiding principle in our strategic planning. This initiative will serve as a foundational reference for the Institute of Modern Physics in its strategic planning and goal-setting, ensuring alignment with its developmental objectives while striving to secure a competitive edge in technological advancement. Our ambition is to engage in substantive research within these realms of high-precision physics, to pursue groundbreaking discoveries, and to stimulate progress in China's nuclear physics landscape, positioning Huizhou as a preeminent global hub for advanced nuclear physics research.展开更多
With the continuous improvement of signal processing accuracy requirements in modern electronic systems,the demand for high-precision analog-to-digital converters(ADCs)is increasing.Sigma-Delta modulator,as the most i...With the continuous improvement of signal processing accuracy requirements in modern electronic systems,the demand for high-precision analog-to-digital converters(ADCs)is increasing.Sigma-Delta modulator,as the most important component of high-precision ADC,is widely used in high-quality audio,high-precision instrument measurement,and other fields due to its advantages of high precision,strong noise resistance,and low hardware cost.This article designs a discrete structure third-order four-bit high-precision Sigma-Delta modulator through modeling,with an oversampling rate set to 512.Under ideal conditions,the simulation results show that the SDNR reaches 152.7db and the ENOB is 25.24bits.After introducing non-ideal noise,the system performance has decreased.The simulation results show that the SDNR is as high as 124.5db and the ENOB is 20.39bits.This indicates that the design can achieve high-precision conversion and provide assistance for further research in the future.展开更多
High-precision analog-to-digital converters(ADCs)serve as fundamental components in modern electronic systems,bridging physical analog world and digital intelligence.They find ubiquitous applications across diverse do...High-precision analog-to-digital converters(ADCs)serve as fundamental components in modern electronic systems,bridging physical analog world and digital intelligence.They find ubiquitous applications across diverse domains,ranging from internet of things(IoT)to embodied artificial intelligence systems.Achieving high precision necessitates various circuit techniques including high-performance amplifiers and advanced calibration schemes.Furthermore,the evolution of ADC architectures has gradually elevated the significance of peripheral circuitry co-design in optimizing system-level performance metrics.In ISSCC 2025,several techniques are proposed to address these challenges.展开更多
INTRODUCTION.Crustal velocity model is crucial for describing the subsurface composition and structure,and has significant implications in offshore oil and gas exploration and marine geophysical engineering(Xie et al....INTRODUCTION.Crustal velocity model is crucial for describing the subsurface composition and structure,and has significant implications in offshore oil and gas exploration and marine geophysical engineering(Xie et al.,2024).Currently,travel time tomography is the most commonly used method for velocity modeling based on ocean bottom seismometer(OBS)data(Zhang et al.,2023;Sambolian et al.,2021).This method usually assumes that the sub-seafloor structure is layered,and therefore faces challenges in high-precision modeling with strong lateral discontinuities.展开更多
Two adaptive friction compensation schemes are developed for a high precision turntable system with nonlinear dynamic friction to handle two types of parametric uncertainties in the friction. Both schemes utilize a no...Two adaptive friction compensation schemes are developed for a high precision turntable system with nonlinear dynamic friction to handle two types of parametric uncertainties in the friction. Both schemes utilize a nonlinear observer/filter structure to compensate for uncertainties in corresponding friction parameters associated with the turntable system. Moreover, in the second scheme, adjustable gains are introduced into the dual nonlin- ear filters and they can be tuned to improve the position tracking performance. In both cases, a Lyapunov-like argument is provided for the global asymptotic stability of the closed-loop system. Simulation results demonstrate the effectiveness of the proposed schemes.展开更多
Based on the theory of elastic mechanics and material mechanics, the orientation precision of the hohl schaft kegel（HSK） tooling system in static and dynamic states is theoretically and experimentally studied. The r...Based on the theory of elastic mechanics and material mechanics, the orientation precision of the hohl schaft kegel（HSK） tooling system in static and dynamic states is theoretically and experimentally studied. The relation between the clamping force and the shank taper is obtained. And a proper clamping force is found to be essential to assure the axial and radial orientation precisions of the HSK tooling system in high speed machining （HSM）. Analytical results show that the reason why the HSK tooling system can keep high precision at the high rotational speed is that the actual axial clamping force keeps the two surfaces of the shank and the spindle in contact all the time.展开更多
This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip ...This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip integration with the sensor. A continuous time auto-zero stabilization technique is studied and employed, with the aim of suppressing the low frequency noises, including the offset voltage, 1/f noise, and temperature drift. The design is based on a 0.35μm CMOS process. With a 3.3V power supply,it maintains a DC open loop gain of more than 100dB and an offset voltage of around 11μV,while the overall power dissipation is only 1.48mW. With this opamp, a pH microsensor is constructed, of which the functionality is verified by experimental tests.展开更多
In this paper, the spectral element method(SEM)is improved to solve the moving load problem. In this method, a structure with uniform geometry and material properties is considered as a spectral element, which means t...In this paper, the spectral element method(SEM)is improved to solve the moving load problem. In this method, a structure with uniform geometry and material properties is considered as a spectral element, which means that the element number and the degree of freedom can be reduced significantly. Based on the variational method and the Laplace transform theory, the spectral stiffness matrix and the equivalent nodal force of the beam-column element are established. The static Green function is employed to deduce the improved function. The proposed method is applied to two typical engineering practices—the one-span bridge and the horizontal jib of the tower crane. The results have revealed the following. First, the new method can yield extremely high-precision results of the dynamic deflection, the bending moment and the shear force in the moving load problem.In most cases, the relative errors are smaller than 1%. Second, by comparing with the finite element method, one can obtain the highly accurate results using the improved SEM with smaller element numbers. Moreover, the method can be widely used for statically determinate as well as statically indeterminate structures. Third, the dynamic deflection of the twin-lift jib decreases with the increase in the moving load speed, whereas the curvature of the deflection increases.Finally, the dynamic deflection, the bending moment and the shear force of the jib will all increase as the magnitude of the moving load increases.展开更多
In order to satisfy the high efficiency and high precision of collaborative robots,this work presents a novel trajectory planning method.First,in Cartesian space,a novel velocity look-ahead control algorithm and a cub...In order to satisfy the high efficiency and high precision of collaborative robots,this work presents a novel trajectory planning method.First,in Cartesian space,a novel velocity look-ahead control algorithm and a cubic polynomial are combined to construct the end-effector trajectory of robots.Then,the joint trajectories can be obtained through the inverse kinematics.In order to improve the smoothness and stability in joint space,the joint trajectories are further adjusted based on the velocity look-ahead control algorithm and quintic B-spline.Finally,the proposed trajectory planning method is tested on a 4-DOF serial collaborative robot.The experimental results indicate that the collaborative robot achieves the high efficiency and high precision,which validates the effectiveness of the proposed method.展开更多
This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array（FPGA） technology,which has been successfully applied to laser grating interference measurement ...This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array（FPGA） technology,which has been successfully applied to laser grating interference measurement and real-time feedback of plasma electron density in HL-2A tokamak.It can track the changes of electron density while setting the starting point of the density curve to zero.In a laboratory test,the measuring accuracy of phase difference is less than 0.1°,the time resolution is 80 ns,and the feedback delay is 180 μs.展开更多
In order to meet the needs of work in numerical weather forecast and in numerical simulations for climate change and ocean current, a kind of difference scheme in high precision in the time direction developed from th...In order to meet the needs of work in numerical weather forecast and in numerical simulations for climate change and ocean current, a kind of difference scheme in high precision in the time direction developed from the completely square-conservative difference scheme in explicit way is built by means of the Taylor expansion. A numerical test with 4-wave Rossby-Haurwitz waves on them and an application of them on the monthly mean current the of South China Sea are carried out, from which, it is found that not only do the new schemes have high harmony and approximate precision but also can the time step of the schemes be lengthened and can much computational time be saved. Therefore, they are worth generalizing and applying.展开更多
The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast w...The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast with the underlying formation, a high frequency gravity anomaly with a certain magnitude will appear. The high frequency gravity anomaly can result in some difficulties for processing and interpreting the gravity data, thereby reducing the usefulness of gravity surveys in loess plateau areas. We carried out a high precision gravity survey in the SHJZ structural zone. During data processing, we applied terrain and loess corrections to effectively remove or suppress the gravity effect resulting from surface undulation and variation of loess thickness. We obtained high precision gravity data which matches well with other geophysical data. The comprehensive interpretation based on the final gravity data help to study local structure integrated with other published geophysical data.展开更多
The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration b...The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications.However,the downward continuation of potential fields is a typical linear inverse problem that is ill-posed.Generalized minimal residuals(GMRES)is an eff ective solution to ill-posed inverse problems,but it is unstable under the condition wherein the GMRES is directly applied in the calculation process.Moreover,the long-term behavior of its iterative computation is a disordered,divergent result.Therefore,to obtain stable solutions,GMRES is applied to solve the normal equations of the downward continuation of potential fields;it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient,thus strengthening the stability conditions of the equations of residual minimization.Finally,the stable downward continuation of the potential fields method is proposed.As indicated by the theoretical data and the measured testing data,the method proposed in this paper has the advantages of high-precision and excellent stability.Furthermore,compared with the Tikhonov iteration method,the proposed method avoids the need to choose regularization parameters.展开更多
Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A ...Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A triple-FOV infrared earth sensor is proposed in this paper. It uses three pieces of standard infrared detectors with a wavelength range of 14;16μm,to sense the horizontal circle by detecting the infrared light emitted from the earth. From which,the geocentric vector can be obtained. A mathematic model is established and a validation model is set up to provide input parameters for the mathematic model. The simulation results of the two models show that the output of the mathematic model coincides with the known parameters. Based on the above analysis,a prototype has been built and tested. The test results show that the angle measurement error is about 0. 002° and hence such a triple-FOV earth sensor is capable to provide high-precision position information for autonomous navigation.展开更多
In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points...In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points of the third-order phase-locked loop(PLL)and find a new Doppler measurement strategy.Based on this finding,a Doppler frequency measurement algorithm with significantly higher measurement accuracy is obtained.In the actual data processing,compared with the existing engineering software,the accuracy of frequency of 1 second integration is about 5.5 times higher when using the new algorithm.The improved algorithm is simple and easy to implement.This improvement can be easily combined with other improvement methods of PLL,so that the performance of PLL can be further improved.展开更多
This article proposes a VGG network with histogram of oriented gradient(HOG) feature fusion(HOG-VGG) for polarization synthetic aperture radar(PolSAR) image terrain classification.VGG-Net has a strong ability of deep ...This article proposes a VGG network with histogram of oriented gradient(HOG) feature fusion(HOG-VGG) for polarization synthetic aperture radar(PolSAR) image terrain classification.VGG-Net has a strong ability of deep feature extraction,which can fully extract the global deep features of different terrains in PolSAR images,so it is widely used in PolSAR terrain classification.However,VGG-Net ignores the local edge & shape features,resulting in incomplete feature representation of the PolSAR terrains,as a consequence,the terrain classification accuracy is not promising.In fact,edge and shape features play an important role in PolSAR terrain classification.To solve this problem,a new VGG network with HOG feature fusion was specifically proposed for high-precision PolSAR terrain classification.HOG-VGG extracts both the global deep semantic features and the local edge & shape features of the PolSAR terrains,so the terrain feature representation completeness is greatly elevated.Moreover,HOG-VGG optimally fuses the global deep features and the local edge & shape features to achieve the best classification results.The superiority of HOG-VGG is verified on the Flevoland,San Francisco and Oberpfaffenhofen datasets.Experiments show that the proposed HOG-VGG achieves much better PolSAR terrain classification performance,with overall accuracies of 97.54%,94.63%,and 96.07%,respectively.展开更多
A generalized simulation method of the tracking,telemetry and control（TT＆C） channel,which is applicable to wideband and arbitrary radio frequency（RF） signal,is proposed.It can accurately simulate the dynamic tran...A generalized simulation method of the tracking,telemetry and control（TT＆C） channel,which is applicable to wideband and arbitrary radio frequency（RF） signal,is proposed.It can accurately simulate the dynamic transmission delay of the arbitrary RF signal in channels,especially regardless of any prior knowledge including signal form,signal parameters,and so on.The proposed method orthogonally demodulates the wideband and arbitrary RF signal to complex baseband by a known local oscillator（LO） signal.Whereafter,it takes measures to obtain the delay reconstruction signal of baseband signals based on the dynamic transmission delay between a ground station and a responder.Meanwhile,it manages to obtain the delay reconstruction signal of LO signals.The simulation output signal（the delayed RF signal） can be achieved through the synthesis of the two delay reconstruction signals mentioned above.The principle and its related key technology are described in detail,and the realizable system architecture is given.展开更多
The exact analytic method was given by [1] . It can be used for arbitrary variable coefficient differential equations and the solution obtained can have the second order convergent precision. In this paper, a new high...The exact analytic method was given by [1] . It can be used for arbitrary variable coefficient differential equations and the solution obtained can have the second order convergent precision. In this paper, a new high precision algorithm is given based on [1], through a bending problem of variable cross-section beams. It can have the fourth convergent precision without increasing computation work. The present computation method is not only simple but also fast. The numerical examples are given at the end of this paper which indicate that the high convergent precision can be obtained using only a few elements. The correctness of the theory in this paper is confirmed.展开更多
A high precision forecasting and prospecting model incorporating the “field theory field structure analysis field simulation”, a temporal and spatial structural framework reflecting local extremely fine structure...A high precision forecasting and prospecting model incorporating the “field theory field structure analysis field simulation”, a temporal and spatial structural framework reflecting local extremely fine structures, is established to make an effective extraction and an integrated analysis of multivariate forecasting information. This model can best show not only the coupling between metallogenic anomalous structure, mineralized structure and information structure, but also the extraction, optimization, matching and summarization of key forecasting information. The technological keys to this model are the fine structural analysis of geological and geophysical and geochemical anomalous fields and metallogenic fields, and the establishment of occurrence patterns for the spatial location of orebodies.展开更多
文摘High-throughput transcriptomics has evolved from bulk RNA-seq to single-cell and spatial profiling,yet its clinical translation still depends on effective integration across diverse omics and data modalities.Emerging foundation models and multimodal learning frameworks are enabling scalable and transferable representations of cellular states,while advances in interpretability and real-world data integration are bridging the gap between discovery and clinical application.This paper outlines a concise roadmap for AI-driven,transcriptome-centered multi-omics integration in precision medicine(Figure 1).
基金supported by the National Natural Science Foundation of China (Grant No.12075326)the Guangdong Basic and Applied Basic Research Foundation (Grant No.2025A1515010669)+2 种基金the Natural Science Foundation of Guangzhou (Grant No.2024A04J6243)the Fundamental Research Funds for the Central Universities in Sun Yat-sen University (No.23xkjc017)the Innovation Training Program for bachelor students in Sun Yat-sen University。
文摘In response to the capabilities presented by the High-Intensity Heavy Ion Accelerator Facility(HIAF) and the Accelerator-Driven Subcritical System(Ci ADS), as well as the proposed Chinese Advanced Nuclear Physics Research Facility(CNUF), we are assembling a consortium of experts in relevant disciplines, both domestically and internationally,to delineate high-precision physics experiments that leverage the state-of-the-art research environment afforded by CNUF.Our focus encompasses six primary domains of inquiry: hadron physics—including endeavors such as the super eta factory and investigations into light hadron structures;muon physics;neutrino physics;neutron physics;the testing of fundamental symmetries;and the exploration of quantum effects within nuclear physics, along with the utilization of vortex accelerators.We aim to foster a well-rounded portfolio of large, medium, and small-scale projects, thus unlocking new scientific avenues and optimizing the potential of the Huizhou large scientific facility. The aspiration for international leadership in scientific research will be a guiding principle in our strategic planning. This initiative will serve as a foundational reference for the Institute of Modern Physics in its strategic planning and goal-setting, ensuring alignment with its developmental objectives while striving to secure a competitive edge in technological advancement. Our ambition is to engage in substantive research within these realms of high-precision physics, to pursue groundbreaking discoveries, and to stimulate progress in China's nuclear physics landscape, positioning Huizhou as a preeminent global hub for advanced nuclear physics research.
文摘With the continuous improvement of signal processing accuracy requirements in modern electronic systems,the demand for high-precision analog-to-digital converters(ADCs)is increasing.Sigma-Delta modulator,as the most important component of high-precision ADC,is widely used in high-quality audio,high-precision instrument measurement,and other fields due to its advantages of high precision,strong noise resistance,and low hardware cost.This article designs a discrete structure third-order four-bit high-precision Sigma-Delta modulator through modeling,with an oversampling rate set to 512.Under ideal conditions,the simulation results show that the SDNR reaches 152.7db and the ENOB is 25.24bits.After introducing non-ideal noise,the system performance has decreased.The simulation results show that the SDNR is as high as 124.5db and the ENOB is 20.39bits.This indicates that the design can achieve high-precision conversion and provide assistance for further research in the future.
文摘High-precision analog-to-digital converters(ADCs)serve as fundamental components in modern electronic systems,bridging physical analog world and digital intelligence.They find ubiquitous applications across diverse domains,ranging from internet of things(IoT)to embodied artificial intelligence systems.Achieving high precision necessitates various circuit techniques including high-performance amplifiers and advanced calibration schemes.Furthermore,the evolution of ADC architectures has gradually elevated the significance of peripheral circuitry co-design in optimizing system-level performance metrics.In ISSCC 2025,several techniques are proposed to address these challenges.
基金financially supported by the National Key R&D Program of China(No.2023YFF0803404)the Zhejiang Provincial Natural Science Foundation(No.LY23D040001)+4 种基金the Open Research Fund of Key Laboratory of Engineering Geophysical Prospecting and Detection of Chinese Geophysical Society(No.CJ2021GB01)the Open Re-search Fund of Changjiang River Scientific Research Institute(No.CKWV20221011/KY)the ZhouShan Science and Technology Project(No.2023C81010)the National Natural Science Foundation of China(No.41904100)supported by Chinese Natural Science Foundation Open Research Cruise(Cruise No.NORC2019–08)。
文摘INTRODUCTION.Crustal velocity model is crucial for describing the subsurface composition and structure,and has significant implications in offshore oil and gas exploration and marine geophysical engineering(Xie et al.,2024).Currently,travel time tomography is the most commonly used method for velocity modeling based on ocean bottom seismometer(OBS)data(Zhang et al.,2023;Sambolian et al.,2021).This method usually assumes that the sub-seafloor structure is layered,and therefore faces challenges in high-precision modeling with strong lateral discontinuities.
文摘Two adaptive friction compensation schemes are developed for a high precision turntable system with nonlinear dynamic friction to handle two types of parametric uncertainties in the friction. Both schemes utilize a nonlinear observer/filter structure to compensate for uncertainties in corresponding friction parameters associated with the turntable system. Moreover, in the second scheme, adjustable gains are introduced into the dual nonlin- ear filters and they can be tuned to improve the position tracking performance. In both cases, a Lyapunov-like argument is provided for the global asymptotic stability of the closed-loop system. Simulation results demonstrate the effectiveness of the proposed schemes.
文摘Based on the theory of elastic mechanics and material mechanics, the orientation precision of the hohl schaft kegel（HSK） tooling system in static and dynamic states is theoretically and experimentally studied. The relation between the clamping force and the shank taper is obtained. And a proper clamping force is found to be essential to assure the axial and radial orientation precisions of the HSK tooling system in high speed machining （HSM）. Analytical results show that the reason why the HSK tooling system can keep high precision at the high rotational speed is that the actual axial clamping force keeps the two surfaces of the shank and the spindle in contact all the time.
文摘This paper presents a high precision CMOS opamp suitable for ISFET readout. The opamp is tailored to provide a constant bias condition for ISFET as part of the readout circuits and,hence,is compatible for single chip integration with the sensor. A continuous time auto-zero stabilization technique is studied and employed, with the aim of suppressing the low frequency noises, including the offset voltage, 1/f noise, and temperature drift. The design is based on a 0.35μm CMOS process. With a 3.3V power supply,it maintains a DC open loop gain of more than 100dB and an offset voltage of around 11μV,while the overall power dissipation is only 1.48mW. With this opamp, a pH microsensor is constructed, of which the functionality is verified by experimental tests.
基金supported by the National Key Technology R&D Program (Grant 2011BAJ02B01-02)the National Natural Science Foundation of China (Grant 11602065)
文摘In this paper, the spectral element method(SEM)is improved to solve the moving load problem. In this method, a structure with uniform geometry and material properties is considered as a spectral element, which means that the element number and the degree of freedom can be reduced significantly. Based on the variational method and the Laplace transform theory, the spectral stiffness matrix and the equivalent nodal force of the beam-column element are established. The static Green function is employed to deduce the improved function. The proposed method is applied to two typical engineering practices—the one-span bridge and the horizontal jib of the tower crane. The results have revealed the following. First, the new method can yield extremely high-precision results of the dynamic deflection, the bending moment and the shear force in the moving load problem.In most cases, the relative errors are smaller than 1%. Second, by comparing with the finite element method, one can obtain the highly accurate results using the improved SEM with smaller element numbers. Moreover, the method can be widely used for statically determinate as well as statically indeterminate structures. Third, the dynamic deflection of the twin-lift jib decreases with the increase in the moving load speed, whereas the curvature of the deflection increases.Finally, the dynamic deflection, the bending moment and the shear force of the jib will all increase as the magnitude of the moving load increases.
文摘In order to satisfy the high efficiency and high precision of collaborative robots,this work presents a novel trajectory planning method.First,in Cartesian space,a novel velocity look-ahead control algorithm and a cubic polynomial are combined to construct the end-effector trajectory of robots.Then,the joint trajectories can be obtained through the inverse kinematics.In order to improve the smoothness and stability in joint space,the joint trajectories are further adjusted based on the velocity look-ahead control algorithm and quintic B-spline.Finally,the proposed trajectory planning method is tested on a 4-DOF serial collaborative robot.The experimental results indicate that the collaborative robot achieves the high efficiency and high precision,which validates the effectiveness of the proposed method.
基金supported by National Natural Science Foundation of China(Nos.11375195,11075048)the National Magnetic Confinement Fusion Science Program of China(No.2013GB104003)
文摘This paper introduces a real-time high precision measurement of phase difference based on Field Programmable Gate Array（FPGA） technology,which has been successfully applied to laser grating interference measurement and real-time feedback of plasma electron density in HL-2A tokamak.It can track the changes of electron density while setting the starting point of the density curve to zero.In a laboratory test,the measuring accuracy of phase difference is less than 0.1°,the time resolution is 80 ns,and the feedback delay is 180 μs.
文摘In order to meet the needs of work in numerical weather forecast and in numerical simulations for climate change and ocean current, a kind of difference scheme in high precision in the time direction developed from the completely square-conservative difference scheme in explicit way is built by means of the Taylor expansion. A numerical test with 4-wave Rossby-Haurwitz waves on them and an application of them on the monthly mean current the of South China Sea are carried out, from which, it is found that not only do the new schemes have high harmony and approximate precision but also can the time step of the schemes be lengthened and can much computational time be saved. Therefore, they are worth generalizing and applying.
文摘The loess plateau is featured by a sharply undulated and remarkably incised surface. The sharp surface undulation means great variation of loess thickness. Since the loess layer exhibits significant density contrast with the underlying formation, a high frequency gravity anomaly with a certain magnitude will appear. The high frequency gravity anomaly can result in some difficulties for processing and interpreting the gravity data, thereby reducing the usefulness of gravity surveys in loess plateau areas. We carried out a high precision gravity survey in the SHJZ structural zone. During data processing, we applied terrain and loess corrections to effectively remove or suppress the gravity effect resulting from surface undulation and variation of loess thickness. We obtained high precision gravity data which matches well with other geophysical data. The comprehensive interpretation based on the final gravity data help to study local structure integrated with other published geophysical data.
基金This research is supported by the National Key Research and Development Program of China under Grant No.2018YFC1505401the Key Research and Development Projects of the Sichuan Science and Technology Department under Grant Nos.2019YFG0460,2020YFG0303,and 2021YJ0031+1 种基金the Technology Research and Development Program of China Railway Group Limited under Grant No.CZ01-Key Point-05the Fundamental Research Funds for the Central Universities under Grant No.2682021GF019.
文摘The downward continuation of potential fields is a process of calculating their values in a lower plane based on those of a certain plane.This technology is not only a data processing method for resource exploration but also plays an extremely important role in military applications.However,the downward continuation of potential fields is a typical linear inverse problem that is ill-posed.Generalized minimal residuals(GMRES)is an eff ective solution to ill-posed inverse problems,but it is unstable under the condition wherein the GMRES is directly applied in the calculation process.Moreover,the long-term behavior of its iterative computation is a disordered,divergent result.Therefore,to obtain stable solutions,GMRES is applied to solve the normal equations of the downward continuation of potential fields;it is also used to prequalify for occasional interruptions in the operation process by adding the damping coefficient,thus strengthening the stability conditions of the equations of residual minimization.Finally,the stable downward continuation of the potential fields method is proposed.As indicated by the theoretical data and the measured testing data,the method proposed in this paper has the advantages of high-precision and excellent stability.Furthermore,compared with the Tikhonov iteration method,the proposed method avoids the need to choose regularization parameters.
基金financially supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA121503 and No.2012AA120603)the National Natural Science Foundation of China(No.61377012)the Tsinghua University Initiative Scientific Research Program(No.20131089242)。
文摘Earth sensors are widely used in spacecraft for attitude determination. They need to have a very large field of view(FOV)( > 120°) and relatively low accuracy while being used in the aircrafts around orbit. A triple-FOV infrared earth sensor is proposed in this paper. It uses three pieces of standard infrared detectors with a wavelength range of 14;16μm,to sense the horizontal circle by detecting the infrared light emitted from the earth. From which,the geocentric vector can be obtained. A mathematic model is established and a validation model is set up to provide input parameters for the mathematic model. The simulation results of the two models show that the output of the mathematic model coincides with the known parameters. Based on the above analysis,a prototype has been built and tested. The test results show that the angle measurement error is about 0. 002° and hence such a triple-FOV earth sensor is capable to provide high-precision position information for autonomous navigation.
基金supported by the National Natural Science Foundation of China(Grant Nos.11773060,11973074,U1831137 and 11703070)National Key Basic Research and Development Program(2018YFA0404702)+1 种基金Shanghai Key Laboratory of Space Navigation and Positioning(3912DZ227330001)the Key Laboratory for Radio Astronomy of CAS。
文摘In deep space exploration,many engineering and scientific requirements require the accuracy of the measured Doppler frequency to be as high as possible.In our paper,we analyze the possible frequency measurement points of the third-order phase-locked loop(PLL)and find a new Doppler measurement strategy.Based on this finding,a Doppler frequency measurement algorithm with significantly higher measurement accuracy is obtained.In the actual data processing,compared with the existing engineering software,the accuracy of frequency of 1 second integration is about 5.5 times higher when using the new algorithm.The improved algorithm is simple and easy to implement.This improvement can be easily combined with other improvement methods of PLL,so that the performance of PLL can be further improved.
基金Sponsored by the Fundamental Research Funds for the Central Universities of China(Grant No.PA2023IISL0098)the Hefei Municipal Natural Science Foundation(Grant No.202201)+1 种基金the National Natural Science Foundation of China(Grant No.62071164)the Open Fund of Information Materials and Intelligent Sensing Laboratory of Anhui Province(Anhui University)(Grant No.IMIS202214 and IMIS202102)。
文摘This article proposes a VGG network with histogram of oriented gradient(HOG) feature fusion(HOG-VGG) for polarization synthetic aperture radar(PolSAR) image terrain classification.VGG-Net has a strong ability of deep feature extraction,which can fully extract the global deep features of different terrains in PolSAR images,so it is widely used in PolSAR terrain classification.However,VGG-Net ignores the local edge & shape features,resulting in incomplete feature representation of the PolSAR terrains,as a consequence,the terrain classification accuracy is not promising.In fact,edge and shape features play an important role in PolSAR terrain classification.To solve this problem,a new VGG network with HOG feature fusion was specifically proposed for high-precision PolSAR terrain classification.HOG-VGG extracts both the global deep semantic features and the local edge & shape features of the PolSAR terrains,so the terrain feature representation completeness is greatly elevated.Moreover,HOG-VGG optimally fuses the global deep features and the local edge & shape features to achieve the best classification results.The superiority of HOG-VGG is verified on the Flevoland,San Francisco and Oberpfaffenhofen datasets.Experiments show that the proposed HOG-VGG achieves much better PolSAR terrain classification performance,with overall accuracies of 97.54%,94.63%,and 96.07%,respectively.
基金supported by the Foundation of Shanghai Aerospace Science and Technology(20120541088)
文摘A generalized simulation method of the tracking,telemetry and control（TT＆C） channel,which is applicable to wideband and arbitrary radio frequency（RF） signal,is proposed.It can accurately simulate the dynamic transmission delay of the arbitrary RF signal in channels,especially regardless of any prior knowledge including signal form,signal parameters,and so on.The proposed method orthogonally demodulates the wideband and arbitrary RF signal to complex baseband by a known local oscillator（LO） signal.Whereafter,it takes measures to obtain the delay reconstruction signal of baseband signals based on the dynamic transmission delay between a ground station and a responder.Meanwhile,it manages to obtain the delay reconstruction signal of LO signals.The simulation output signal（the delayed RF signal） can be achieved through the synthesis of the two delay reconstruction signals mentioned above.The principle and its related key technology are described in detail,and the realizable system architecture is given.
文摘The exact analytic method was given by [1] . It can be used for arbitrary variable coefficient differential equations and the solution obtained can have the second order convergent precision. In this paper, a new high precision algorithm is given based on [1], through a bending problem of variable cross-section beams. It can have the fourth convergent precision without increasing computation work. The present computation method is not only simple but also fast. The numerical examples are given at the end of this paper which indicate that the high convergent precision can be obtained using only a few elements. The correctness of the theory in this paper is confirmed.
基金Thispaperisco sponsoredbytheStateKeyBasicResearchProject(G1 9990 4 32 0 7 3) byBackboneTeacherResearchProjectundertheMin i
文摘A high precision forecasting and prospecting model incorporating the “field theory field structure analysis field simulation”, a temporal and spatial structural framework reflecting local extremely fine structures, is established to make an effective extraction and an integrated analysis of multivariate forecasting information. This model can best show not only the coupling between metallogenic anomalous structure, mineralized structure and information structure, but also the extraction, optimization, matching and summarization of key forecasting information. The technological keys to this model are the fine structural analysis of geological and geophysical and geochemical anomalous fields and metallogenic fields, and the establishment of occurrence patterns for the spatial location of orebodies.
