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
Silicon(Si)diffraction microlens arrays are usually used to integrating with infrared focal plane arrays(IRFPAs)to improve their performance.The errors of lithography are unavoidable in the process of the Si diffrac-t...Silicon(Si)diffraction microlens arrays are usually used to integrating with infrared focal plane arrays(IRFPAs)to improve their performance.The errors of lithography are unavoidable in the process of the Si diffrac-tion microlens arrays preparation in the conventional engraving method.It has a serious impact on its performance and subsequent applications.In response to the problem of errors of Si diffraction microlens arrays in the conven-tional method,a novel self-alignment method for high precision Si diffraction microlens arrays preparation is pro-posed.The accuracy of the Si diffractive microlens arrays preparation is determined by the accuracy of the first li-thography mask in the novel self-alignment method.In the subsequent etching,the etched area will be protected by the mask layer and the sacrifice layer or the protective layer.The unprotection area is carved to effectively block the non-etching areas,accurately etch the etching area required,and solve the problem of errors.The high precision Si diffraction microlens arrays are obtained by the novel self-alignment method and the diffraction effi-ciency could reach 92.6%.After integrating with IRFPAs,the average blackbody responsity increased by 8.3%,and the average blackbody detectivity increased by 10.3%.It indicates that the Si diffraction microlens arrays can improve the filling factor and reduce crosstalk of IRFPAs through convergence,thereby improving the perfor-mance of the IRFPAs.The results are of great reference significance for improving their performance through opti-mizing the preparation level of micro nano devices.展开更多
In the development of the Gravity-1 launch vehicle, solid rocket motors without a thrust termination mechanism created great challenges for ascent guidance. To resolve this problem, the Gravity-1 GNC system used cross...In the development of the Gravity-1 launch vehicle, solid rocket motors without a thrust termination mechanism created great challenges for ascent guidance. To resolve this problem, the Gravity-1 GNC system used cross product guidance in the core 2nd stage, and a nonlinear adaptive guidance algorithm in core 3rd stage, in order to achieve high orbit injection precision. On January 11, 2024, the Gravity-1 launch vehicle successfully carried out its maiden flight from a mobile sea platform off the coast of Haiyang in Shandong province, inserting its payload into a low earth orbit at an altitude of 500 kilometers, validating the guidance algorithm.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
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
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
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
Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control ...Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control of the spatial position and distribution of a single cell or single component droplet.In this study,to accurately achieve the directional deposition of different cells and biological materials in the spatial position for the construction of large transplantable tissues and organs,a high-precision multichannel 3D bioprinter with submicron-level motion accuracy is designed,and concurrent and synergistic printing methods are proposed.Based on the high-precision motion characteristics of the gantry structure and the requirements of concurrent and synergistic printing,a 3D bioprint-ing system with a set of 6 channels is designed to achieve six-in-one printing.Based on the Visual C++environ-ment,a control system software that integrates the programmable multi-axis controller(PMAC)motion,pneumatic,and temperature control subsystems was developed and designed.Finally,based on measurements and experiments,the 3D bioprinter and its control system was verified to fulfil the requirements of multichannel,concurrent,and syn-ergistic printing with submicron-level motion accuracy,significantly shortening the printing time and improving the printing efficiency.This study not only provides an equipment basis for printing complex heterogeneous tissue structures,but also improves the flexibility and functionality of bioprinting,and ultimately makes the construction of complex multicellular tissues or organs possible.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
1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its...1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk展开更多
The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and...The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and density, suitable explosives per meter in the NONEL tube, base firing charge and the main specifications. The improvement of the characteristics of FDG-1 detonator has been tested systematically. The testing method is reliable and its precision can meet the demand for usage.展开更多
As one of the most effective methods for magnetite exploration, high-precision magnetic survey has always played an important role in finding the location and distribution of deep buried magnetite, which can directly ...As one of the most effective methods for magnetite exploration, high-precision magnetic survey has always played an important role in finding the location and distribution of deep buried magnetite, which can directly reflect the magnetic anomaly characteristics of magnetic iron deposits. In this paper, a high-precision magnetic survey was carried out in a work area in southern Shaanxi with a magnetic network of 100× 20m. Combined with geological data and through data processing and analysis and interpretation, the distribution, scale and spatial distribution of concealed and semi-concealed magnetic ore bodies related to mineralization in the work area were basically identified, and the general scope and location of magnetic anomalies in the work area were circled, providing a basis for scientific and reasonable development of magnetite in the area.展开更多
A new solution of combination network of GPS and high precise distance measurements with EDM is proposed. Meanwhile, it’s inadvisable only using GPS network without distance measurements. Three schemes: terrestrial n...A new solution of combination network of GPS and high precise distance measurements with EDM is proposed. Meanwhile, it’s inadvisable only using GPS network without distance measurements. Three schemes: terrestrial network, GPS network and combination network are discussed for horizontal control network design of Xiangjiaba Dam in view of precision, reliability, coordinate and outlay in detail.展开更多
Detecting multiple parameters in salt spray environments is critical,as it significantly enhances the stability and reliability of real-time corrosion monitoring systems.However,current sensor strategies for detecting...Detecting multiple parameters in salt spray environments is critical,as it significantly enhances the stability and reliability of real-time corrosion monitoring systems.However,current sensor strategies for detecting salt spray parameters face challenges such as poor timeliness,short lifespan,and low detection accuracy.This work introduces a multi-parameter micro-nano sensor based on Micro-Electro-Mechanical Systems(MEMS)technology,which integrates temperature,humidity,and conductivity detection units.Through a systematic characterization of the sensor’s performance,the sensor demonstrates excellent linearity,ideal detection ranges,and satisfactory accuracies with detection accuracies of±0.1℃ for temperature,±2%RH for humidity,and±0.1 mS/cm for conductivity.This sensor offers a practical strategy for calculating the instantaneous corrosion rate of aircraft over the ocean.Additionally,based on the positive correlation between the three parameters and the liquid film thickness,a critical threshold determination method for the dynamic behavior of the sensor surface liquid film is further explored.This method macroscopically distinguishes the phase transition boundary between dry and wet states of the liquid film,offering a theoretical foundation for differentiated corrosion rate assessment and improved corrosion prediction accuracy.Highprecision monitoring of environmental parameters during long-term salt spray and atmospheric exposure experiments is achieved using a self-developed online testing system.Real-time data compensation is also provided to improve the sensor’s stability and accuracy.Consequently,the proposed high-precision,miniaturized,and massproducible multi-parameter sensor holds great promise as a competitive device for detecting salt spray environmental parameters in real-time corrosion monitoring systems for the aerospace field.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
Stretchable hybrid systems have been attracting tremendous attention for their essential role in soft robotics,on-skin electronics,and implantable devices.Both rigid and soft functional modules are typically required ...Stretchable hybrid systems have been attracting tremendous attention for their essential role in soft robotics,on-skin electronics,and implantable devices.Both rigid and soft functional modules are typically required in those devices.Consequently,ensuring stable electrical contact between rigid and soft modules is a vital part.Here,we propose a simple,universal,and scalable strategy for the stretchable hybrid system through a highly precise printable liquid metal particle-based conductor and adhesive fluorine rubber substrate.The properties of liquid metal particle-based conductors could be easily tuned to realize high-precision patterning,large-scale printing,and the ability to print on various substrates.Additionally,the fluorine rubber substrate could form strong interfacial adhesion with various components and materials through simply pressing and heating,hence enabling stable electrical contact.Furthermore,we prepared a stretchable hybrid light-emitting diode(LED)display system and employed it in on-skin visualization of pressure levels,which perfectly combined rigid and soft modules,thus demonstrating the promising potential applications in complex multifunctional stretchable hybrid systems for emerging technologies.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
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
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.
基金Supported by the National Natural Science Foundation of China(NSFC 62105100)the National Key research and development program in the 14th five year plan(2021YFA1200700)。
文摘Silicon(Si)diffraction microlens arrays are usually used to integrating with infrared focal plane arrays(IRFPAs)to improve their performance.The errors of lithography are unavoidable in the process of the Si diffrac-tion microlens arrays preparation in the conventional engraving method.It has a serious impact on its performance and subsequent applications.In response to the problem of errors of Si diffraction microlens arrays in the conven-tional method,a novel self-alignment method for high precision Si diffraction microlens arrays preparation is pro-posed.The accuracy of the Si diffractive microlens arrays preparation is determined by the accuracy of the first li-thography mask in the novel self-alignment method.In the subsequent etching,the etched area will be protected by the mask layer and the sacrifice layer or the protective layer.The unprotection area is carved to effectively block the non-etching areas,accurately etch the etching area required,and solve the problem of errors.The high precision Si diffraction microlens arrays are obtained by the novel self-alignment method and the diffraction effi-ciency could reach 92.6%.After integrating with IRFPAs,the average blackbody responsity increased by 8.3%,and the average blackbody detectivity increased by 10.3%.It indicates that the Si diffraction microlens arrays can improve the filling factor and reduce crosstalk of IRFPAs through convergence,thereby improving the perfor-mance of the IRFPAs.The results are of great reference significance for improving their performance through opti-mizing the preparation level of micro nano devices.
文摘In the development of the Gravity-1 launch vehicle, solid rocket motors without a thrust termination mechanism created great challenges for ascent guidance. To resolve this problem, the Gravity-1 GNC system used cross product guidance in the core 2nd stage, and a nonlinear adaptive guidance algorithm in core 3rd stage, in order to achieve high orbit injection precision. On January 11, 2024, the Gravity-1 launch vehicle successfully carried out its maiden flight from a mobile sea platform off the coast of Haiyang in Shandong province, inserting its payload into a low earth orbit at an altitude of 500 kilometers, validating the guidance algorithm.
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 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.
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Supported by National Key Research and Development Program of China(Grant No.2018YFA0703000)National Natural Science Foundation of China(Grant No.51875518)Fundamental Research Funds for the Central Universities of China(Grant Nos.2019XZZX003-02,2019FZA4002).
文摘Three-dimensional(3D)printing technology is expected to solve the organ shortage problem.However,owing to the accuracy limitations,it is difficult for the current bioprinting technology to achieve an accurate control of the spatial position and distribution of a single cell or single component droplet.In this study,to accurately achieve the directional deposition of different cells and biological materials in the spatial position for the construction of large transplantable tissues and organs,a high-precision multichannel 3D bioprinter with submicron-level motion accuracy is designed,and concurrent and synergistic printing methods are proposed.Based on the high-precision motion characteristics of the gantry structure and the requirements of concurrent and synergistic printing,a 3D bioprint-ing system with a set of 6 channels is designed to achieve six-in-one printing.Based on the Visual C++environ-ment,a control system software that integrates the programmable multi-axis controller(PMAC)motion,pneumatic,and temperature control subsystems was developed and designed.Finally,based on measurements and experiments,the 3D bioprinter and its control system was verified to fulfil the requirements of multichannel,concurrent,and syn-ergistic printing with submicron-level motion accuracy,significantly shortening the printing time and improving the printing efficiency.This study not only provides an equipment basis for printing complex heterogeneous tissue structures,but also improves the flexibility and functionality of bioprinting,and ultimately makes the construction of complex multicellular tissues or organs possible.
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.
基金supported by funds from the National Natural Science Foundation of China (No. 41521062, 41490631)
文摘1 Introduction The short-lived 182Hf-182W system is generally acknowledged as the best chronometer of metal-silicate segregation that occurred during the early evolution of asteroids and terrestrial planets due to its following properties:(1)Hf-W fractionation commonly occurs during metal-silicate differentiation;(2)Both Hf and W are highly refractory elements,therefore most bulk
文摘The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and density, suitable explosives per meter in the NONEL tube, base firing charge and the main specifications. The improvement of the characteristics of FDG-1 detonator has been tested systematically. The testing method is reliable and its precision can meet the demand for usage.
文摘As one of the most effective methods for magnetite exploration, high-precision magnetic survey has always played an important role in finding the location and distribution of deep buried magnetite, which can directly reflect the magnetic anomaly characteristics of magnetic iron deposits. In this paper, a high-precision magnetic survey was carried out in a work area in southern Shaanxi with a magnetic network of 100× 20m. Combined with geological data and through data processing and analysis and interpretation, the distribution, scale and spatial distribution of concealed and semi-concealed magnetic ore bodies related to mineralization in the work area were basically identified, and the general scope and location of magnetic anomalies in the work area were circled, providing a basis for scientific and reasonable development of magnetite in the area.
基金Supported bythe National 973 Programof China(No.2003CB716705) International Cooperative Fund of European Union(No.EVGI-CT-2002-00061) .
文摘A new solution of combination network of GPS and high precise distance measurements with EDM is proposed. Meanwhile, it’s inadvisable only using GPS network without distance measurements. Three schemes: terrestrial network, GPS network and combination network are discussed for horizontal control network design of Xiangjiaba Dam in view of precision, reliability, coordinate and outlay in detail.
基金supported by the grant from the National Science Foundation of China(62271272)the Open Fund Project of Key Laboratory of Ocean Observation Technology,MNR(2023klootA09)sponsored by Ningbo Science and Technology Project(2022Z092).
文摘Detecting multiple parameters in salt spray environments is critical,as it significantly enhances the stability and reliability of real-time corrosion monitoring systems.However,current sensor strategies for detecting salt spray parameters face challenges such as poor timeliness,short lifespan,and low detection accuracy.This work introduces a multi-parameter micro-nano sensor based on Micro-Electro-Mechanical Systems(MEMS)technology,which integrates temperature,humidity,and conductivity detection units.Through a systematic characterization of the sensor’s performance,the sensor demonstrates excellent linearity,ideal detection ranges,and satisfactory accuracies with detection accuracies of±0.1℃ for temperature,±2%RH for humidity,and±0.1 mS/cm for conductivity.This sensor offers a practical strategy for calculating the instantaneous corrosion rate of aircraft over the ocean.Additionally,based on the positive correlation between the three parameters and the liquid film thickness,a critical threshold determination method for the dynamic behavior of the sensor surface liquid film is further explored.This method macroscopically distinguishes the phase transition boundary between dry and wet states of the liquid film,offering a theoretical foundation for differentiated corrosion rate assessment and improved corrosion prediction accuracy.Highprecision monitoring of environmental parameters during long-term salt spray and atmospheric exposure experiments is achieved using a self-developed online testing system.Real-time data compensation is also provided to improve the sensor’s stability and accuracy.Consequently,the proposed high-precision,miniaturized,and massproducible multi-parameter sensor holds great promise as a competitive device for detecting salt spray environmental parameters in real-time corrosion monitoring systems for the aerospace field.
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.
基金the National Natural Science Foundation of China(Nos.52125205,U20A20166,and 52192614)National Key Research and Development Program of China(Nos.2021YFB3200302 and 2021YFB3200304)+2 种基金Natural Science Foundation of Beijing Municipality(No.2222088)Shenzhen Science and Technology Program(No.KQTD20170810105439418)the Fundamental Research Funds for the Central Universities.
文摘Stretchable hybrid systems have been attracting tremendous attention for their essential role in soft robotics,on-skin electronics,and implantable devices.Both rigid and soft functional modules are typically required in those devices.Consequently,ensuring stable electrical contact between rigid and soft modules is a vital part.Here,we propose a simple,universal,and scalable strategy for the stretchable hybrid system through a highly precise printable liquid metal particle-based conductor and adhesive fluorine rubber substrate.The properties of liquid metal particle-based conductors could be easily tuned to realize high-precision patterning,large-scale printing,and the ability to print on various substrates.Additionally,the fluorine rubber substrate could form strong interfacial adhesion with various components and materials through simply pressing and heating,hence enabling stable electrical contact.Furthermore,we prepared a stretchable hybrid light-emitting diode(LED)display system and employed it in on-skin visualization of pressure levels,which perfectly combined rigid and soft modules,thus demonstrating the promising potential applications in complex multifunctional stretchable hybrid systems for emerging technologies.
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 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.
