In this paper, both output-feedback iterative learning control(ILC) and repetitive learning control(RLC) schemes are proposed for trajectory tracking of nonlinear systems with state-dependent time-varying uncertaintie...In this paper, both output-feedback iterative learning control(ILC) and repetitive learning control(RLC) schemes are proposed for trajectory tracking of nonlinear systems with state-dependent time-varying uncertainties. An iterative learning controller, together with a state observer and a fully-saturated learning mechanism, through Lyapunov-like synthesis, is designed to deal with time-varying parametric uncertainties. The estimations for outputs, instead of system outputs themselves, are applied to form the error equation, which helps to establish convergence of the system outputs to the desired ones. This method is then extended to repetitive learning controller design. The boundedness of all the signals in the closed-loop is guaranteed and asymptotic convergence of both the state estimation error and the tracking error is established in both cases of ILC and RLC. Numerical results are presented to verify the effectiveness of the proposed methods.展开更多
In complex environments, many distributed multiagent systems are described with the fractional-order dynamics.In this paper, containment control of fractional-order multiagent systems with multiple leader agents are s...In complex environments, many distributed multiagent systems are described with the fractional-order dynamics.In this paper, containment control of fractional-order multiagent systems with multiple leader agents are studied. Firstly,the collaborative control of fractional-order multi-agent systems(FOMAS) with multiple leaders is analyzed in a directed network without delays. Then, by using Laplace transform and frequency domain theorem, containment consensus of networked FOMAS with time delays is investigated in an undirected network, and a critical value of delays is obtained to ensure the containment consensus of FOMAS. Finally, numerical simulations are shown to verify the results.展开更多
The noise of closed loop micro-electromechanical systems(MEMS) capacitive accelerometer is treated as one of the significant performance specifications.Traditional optimization of noise performance often focuses on de...The noise of closed loop micro-electromechanical systems(MEMS) capacitive accelerometer is treated as one of the significant performance specifications.Traditional optimization of noise performance often focuses on designing large capacitive sensitivity accelerometer and applying closed loop structure to shape total noise,but different noise sources in closed loop and their behaviors at low frequencies are seldom carefully studied,especially their behaviors with different electronic parameters.In this work,a thorough noise analysis is established focusing on the four noise sources transfer functions near 0 Hz with simplified electronic parameters in closed loop,and it is found that the total electronic noise equivalent acceleration varies differently at different frequency points,such that the noise spectrum shape at low frequencies can be altered from 1/f noise-like shape to flat spectrum shape.The bias instability changes as a consequence.With appropriate parameters settings,the 670 Hz resonant frequency accelerometer can reach resolution of 2.6 μg/(Hz)1/2 at 2 Hz and 6 μg bias instability,and 1300 Hz accelerometer can achieve 5μg/(Hz)1/2 at 2 Hz and 31 μg bias instability.Both accelerometers have flat spectrum profile from 2 Hz to 15 Hz.展开更多
A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based...A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based on this the vari-able-frequency-control(VFC) method for belt conveyor drive was fully discussed with focus on its application in medium-high voltage range. The principle of Neutral Point Clamped (NPC) Three-Level Inverter using high-voltage IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive were illustrated.展开更多
The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of int...The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of intrinsically safe circuit, which has two working modes: continuous inductive current (CCM — continuous conduction mode) and dis- crete inductance current (DCM — discontinuous conduction mode). The operating state of the continuous inductive current mode is analyzed in detail and the energy of discharge spark in various operating modes is discussed. The total energy will decrease with the increase of switch frequency, in a switching cycle; the discharge spark energy has a maxi- mum and a minimum value. Therefore, the Buck converter has smaller discharge spark energy than the linear power circuit and the switch type of intrinsically safe circuit can enhance the output power and the conversion efficiency of the intrinsically safe power.展开更多
A strong animal survival instinct is to approach objects and situations that are of benefit and to avoid risk.In humans,a large proportion of mental disorders are accompanied by impairments in risk avoidance.One of th...A strong animal survival instinct is to approach objects and situations that are of benefit and to avoid risk.In humans,a large proportion of mental disorders are accompanied by impairments in risk avoidance.One of the most important genes involved in mental disorders is disrupted-in-schizophrenia-1(DISC1),and animal models in which this gene has some level of dysfunction show emotion-related impairments.However,it is not known whether DISC1 mouse models have an impairment in avoiding potential risks.In the present study,we used DISC1-N terminal truncation(DISC1-N^(TM))mice to investigate risk avoidance and found that these mice were impaired in risk avoidance on the elevated plus maze(EPM)and showed reduced social preference in a three-chamber social interaction test.Following EPM tests,c-Fos expression levels indicated that the nucleus accumbens(NAc)was associated with risk-avoidance behavior in DISC1-N^(TM)mice.In addition,in vivo electrophysiological recordings following tamoxifen administration showed that the firing rates of fast-spiking neurons(FS)in the NAc were significantly lower in DISC1-N^(TM)mice than in wild-type(WT)mice.In addition,in vitro patch clamp recording revealed that the frequency of action potentials stimulated by current injection was lower in parvalbumin(PV)neurons in the NAc of DISC1-N^(TM)mice than in WT controls.The impairment of risk avoidance in DISC1-N^(TM)mice was rescued using optogenetic tools that activated NAcPV neurons.Finally,inhibition of the activity of NAcPV neurons in PV-Cre mice mimicked the risk-avoidance impairment found in DISC1-N^(TM)mice during tests on the elevated zero maze.Taken together,our findings confirm an impairment in risk avoidance in DISC1-N^(TM)mice and suggest that reduced excitability of NAc^(PV) neurons is responsible.展开更多
As human‐machine interaction(HMI)in healthcare continues to evolve,the issue of trust in HMI in healthcare has been raised and explored.It is critical for the development and safety of healthcare that humans have pro...As human‐machine interaction(HMI)in healthcare continues to evolve,the issue of trust in HMI in healthcare has been raised and explored.It is critical for the development and safety of healthcare that humans have proper trust in medical machines.Intelligent machines that have applied machine learning(ML)technologies continue to penetrate deeper into the medical environment,which also places higher demands on intelligent healthcare.In order to make machines play a role in HMI in healthcare more effectively and make human‐machine cooperation more harmonious,the authors need to build good humanmachine trust(HMT)in healthcare.This article provides a systematic overview of the prominent research on ML and HMT in healthcare.In addition,this study explores and analyses ML and three important factors that influence HMT in healthcare,and then proposes a HMT model in healthcare.Finally,general trends are summarised and issues to consider addressing in future research on HMT in healthcare are identified.展开更多
Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good me-chanical properties and ability to completely dissolve in the body over time,eliminating the need for a second...Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good me-chanical properties and ability to completely dissolve in the body over time,eliminating the need for a secondary surgery to remove the implant.Despite extensive research on these materials,there remains a dearth of infor-mation regarding critical factors that affect implant performance in clinical applications,such as the in vivo pH and mechanical loading conditions.We developed a measurement system with implantable strain,temperature,pH and motion sensors to characterize magnesium and titanium plates,fixating bilateral zygomatic arch osteotomies in three Swiss alpine sheep for eight weeks.pH 1-2 mm above titanium plates was 6.6±0.4,while for magnesium plates it was slightly elevated to 7.4±0.8.Strains on magnesium plates were higher than on titanium plates,possibly due to the lower Young’s modulus of magnesium.One magnesium plate experienced excessive loading,which led to plate failure within 31 h.This is,to our knowledge,the first in vivo strain,temperature,and pH data recorded for magnesium implants used for fracture fixation.These results provide insight into magnesium degradation and its influence on the in vivo environment,and may help to improve material and implant design for future clinical applications.展开更多
Optoacoustic signals behave nonlinearly at light fluences above a few mJ/cm^(2),which may affect the interpretation and quantification of measurements.It has been proposed that optoacoustic nonlinearity arises from th...Optoacoustic signals behave nonlinearly at light fluences above a few mJ/cm^(2),which may affect the interpretation and quantification of measurements.It has been proposed that optoacoustic nonlinearity arises from the heat-induced formation of nanobubbles or changes in local thermo-physical parameters.However,such explanations are only valid at much higher fluences than typically used in biomedical optoacoustic imaging(>20 mJ/cm^(2))or in the presence of materials with high absorption coefficients such as gold nanoparticles.We propose herein that electromagnetic permittivity changes in response to photon absorption are major source of optoacoustic signal nonlinearity at low fluences.We provide theoretical and experimental evidence that supports this postulation and show that optoacoustic pressure responses due to permittivity changes,which are function of thermally excited third-order nonlinear susceptibility,can explain the nonlinear behavior of the optoacoustic signal.Since different materials exhibit different thermally excited third-order nonlinear susceptibility,this property could function as a new contrast mechanism that can identify the sensitivity of a substance’s dielectric constant to photon-induced temperature changes.Consequently,we propose an imaging method based on nonlinear optoacoustic signals that exploits this newly identified contrast mechanism.These findings may have far-reaching implications for improving the accuracy of optoacoustics and utilizing the proposed new contrast mechanism would advance our understanding of cellular and tissue functionality.展开更多
For many years a soil water content sensor with low cost, reliability and sufficient accuracy has been desirable. Thus, an improved measurement method based on the frequency domain (FD) principle for determining soil ...For many years a soil water content sensor with low cost, reliability and sufficient accuracy has been desirable. Thus, an improved measurement method based on the frequency domain (FD) principle for determining soil water content was considered. Unlike other measurement principles, a new measurable index, η, which was independent of the output impedance and the amplitude of the oscillator while relying on the electrical impedance of a multi-pin probe, was pro- posed. Moreover, a model for processing the impedance of the multi-pin soil probe was developed, and several important electrical parameters for establishing their operating ranges applicable to this probe were evaluated. In order to confirm the theoretical analysis, an experiment was conducted with a 4-pin probe. Using the developed model, the relationship between the proposed index η and soil volumetric water content was shown to be linear (R2 = 0.9921). Thus, as the measurable index, η seemed satisfactory.展开更多
Missing value is one of the main factors that cause dirty data.Without high-quality data,there will be no reliable analysis results and precise decision-making.Therefore,the data warehouse needs to integrate high-qual...Missing value is one of the main factors that cause dirty data.Without high-quality data,there will be no reliable analysis results and precise decision-making.Therefore,the data warehouse needs to integrate high-quality data consistently.In the power system,the electricity consumption data of some large users cannot be normally collected resulting in missing data,which affects the calculation of power supply and eventually leads to a large error in the daily power line loss rate.For the problem of missing electricity consumption data,this study proposes a group method of data handling(GMDH)based data interpolation method in distribution power networks and applies it in the analysis of actually collected electricity data.First,the dependent and independent variables are defined from the original data,and the upper and lower limits of missing values are determined according to prior knowledge or existing data information.All missing data are randomly interpolated within the upper and lower limits.Then,the GMDH network is established to obtain the optimal complexity model,which is used to predict the missing data to replace the last imputed electricity consumption data.At last,this process is implemented iteratively until the missing values do not change.Under a relatively small noise level(α=0.25),the proposed approach achieves a maximum error of no more than 0.605%.Experimental findings demonstrate the efficacy and feasibility of the proposed approach,which realizes the transformation from incomplete data to complete data.Also,this proposed data interpolation approach provides a strong basis for the electricity theft diagnosis and metering fault analysis of electricity enterprises.展开更多
Despite the importance of placental function in embryonic development,it remains poorly understood and challenging to characterize,primarily due to the lack of non-invasive imaging tools capable of monitoring placenta...Despite the importance of placental function in embryonic development,it remains poorly understood and challenging to characterize,primarily due to the lack of non-invasive imaging tools capable of monitoring placental and foetal oxygenation and perfusion parameters during pregnancy.We developed an optoacoustic tomography approach for real-time imaging through entire ~4 cm cross-sections of pregnant mice.Functional changes in both maternal and embryo regions were studied at different gestation days when subjected to an oxygen breathing challenge and perfusion with indocyanine green.Structural phenotyping of the cross-sectional scans highlighted different internal organs,whereas multi-wavelength acquisitions enabled non-invasive label-free spectroscopic assessment of blood-oxygenation parameters in foeto-placental regions,rendering a strong correlation with the amount of oxygen administered.Likewise,the placental function in protecting the embryo from extrinsically administered agents was substantiated.The proposed methodology may potentially further serve as a probing mechanism to appraise embryo development during pregnancy in the clinical setting.展开更多
Underwater magnetic induction(MI)-assisted acoustic cooperative multiple-input-multipleoutput(MIMO) has been recently proposed as a promising technique for underwater wireless sensor networks(UWSNs).For the more,the e...Underwater magnetic induction(MI)-assisted acoustic cooperative multiple-input-multipleoutput(MIMO) has been recently proposed as a promising technique for underwater wireless sensor networks(UWSNs).For the more,the energy utilization of energy-constrained sensor nodes is one of the key issues in UWSNs,and it relates to the network lifetime.In this paper,we present an energy-efficient data collection for underwater MI-assisted acoustic cooperative MIMO wireless sensor networks(WSNs),including the formation of cooperative MIMO and relay link establishment.Firstly,the cooperative MIMO is formed by considering its expected transmission range and the energy balance of nodes with it.Particularly,from the perspective of the node’s energy consumption,the expected cooperative MIMO size and the selection of master node(MN) are proposed.Sequentially,to improve the coverage of the networks and prolong the network lifetime,relay links are established by relay selection algorithm that using matching theory.Finally,the simulation results show that the proposed data collection improves its efficiency,reduces the energy consumption of the master node,improves the networks’ coverage,and extends the network lifetime.展开更多
Understanding the morphology and function of large-scale cerebrovascular networks is crucial for studying brain health and disease.However,reconciling the demands for imaging on a broad scale with the precision of hig...Understanding the morphology and function of large-scale cerebrovascular networks is crucial for studying brain health and disease.However,reconciling the demands for imaging on a broad scale with the precision of highresolution volumetric microscopy has been a persistent challenge.In this study,we introduce Bessel beam optical coherence microscopy with an extended focus to capture the full cortical vascular hierarchy in mice over 1000×1000×360μm^(3)field-of-view at capillary level resolution.The post-processing pipeline leverages a supervised deep learning approach for precise 3D segmentation of high-resolution angiograms,hence permitting reliable examination of microvascular structures at multiple spatial scales.Coupled with high-sensitivity Doppler optical coherence tomography,our method enables the computation of both axial and transverse blood velocity components as well as vessel-specific blood flow direction,facilitating a detailed assessment of morpho-functional characteristics across all vessel dimensions.Through graph-based analysis,we deliver insights into vascular connectivity,all the way from individual capillaries to broader network interactions,a task traditionally challenging for in vivo studies.The new imaging and analysis framework extends the frontiers of research into cerebrovascular function and neurovascular pathologies.展开更多
A wideband sensitive needle ultrasound sensor based on a polarized PVDF-TrFE copolymer piezoelectric film has been developed,which is capable of providing a noise equivalent pressure of 14 Pa and a uniform frequency r...A wideband sensitive needle ultrasound sensor based on a polarized PVDF-TrFE copolymer piezoelectric film has been developed,which is capable of providing a noise equivalent pressure of 14 Pa and a uniform frequency response ranging from 1 to 25 MHz.Its high sensitivity(1.6μV∕Pa)and compact size were achieved by capitalizing on the large electromechanical coupling coefficient of PVDF-TrFE and minimizing parasitic capacitance in a two-stage amplifier structure.The detection sensitivity of the newly designed sensor outperformed commercially available hydrophones with an equivalent sensing element area by a factor of 9.The sensor has been successfully integrated into a light scanning optoacoustic microscopy(OAM)system with a limited working space.Submicrometer resolution images were subsequently attained from living mice without employing signal averaging.The miniature sensor design can readily be integrated into various OAM systems and further facilitate multimodal imaging system implementations.展开更多
High-speed volumetric optoacoustic tomography(VOT)offers powerful means for noninvasive,detailed visualization of rapid cardiac dynamics in mice.However,current implementations suffer from non-uniform light delivery i...High-speed volumetric optoacoustic tomography(VOT)offers powerful means for noninvasive,detailed visualization of rapid cardiac dynamics in mice.However,current implementations suffer from non-uniform light delivery into the thoracic area,which results in diminished penetration depth,limited field-of-view,and compromised quantification abilities.In this work,we devised a new VOT approach featuring hexagonally-shaped light delivery optimized for whole-heart imaging and an expedited imaging speed of 200 volumes per second using a custom-made spherical array transducer.The enhanced imaging performance was confirmed with calibration phantoms and noninvasive imaging of the murine heart.We capitalized on the reduced hemoglobin absorption in the second near-infrared(NIR-II)spectral window to mitigate the strong light attenuation by whole blood within the cardiac chambers while further employing copper sulfide nanoparticles featuring a strong NIR-II absorption to quantify cardiac functional parameters across the entire heart in vivo.The new approach can thus facilitate the monitoring of cardiac abnormalities and assessment of therapeutic interventions.展开更多
Deformable manipulation has attracted a lot of attention in the field of robotics,especially in medical applications.However,manipulating deformable objects faces various challenges,mainly including their complex dyna...Deformable manipulation has attracted a lot of attention in the field of robotics,especially in medical applications.However,manipulating deformable objects faces various challenges,mainly including their complex dynamic properties and unpredictable nonlinear deformations.It is difficult to provide a basis for deformable object measurements without effective control methods that provide intelligent and accurate position control,and this research also provides a premise for deformable object measurements.To address these issues,this paper proposes an online iterative perception policy(IPP)method,which does not require large-scale deep network training.This method is able to perceive transformations through an iterative process,and achieve efficient and accurate control of deformable objects.Extensive experiments in the simulation environment and the real scene are conducted to validate the effectiveness and superiority of the proposed method,as well as to compare with advanced algorithms(linear–quadratic regulator(LQR),sliding mode control(SMC),model predictive control(MPC),and heuristic).The experimental results reveal that IPP outperforms other approaches in terms of convergence,stability,robustness and flexibility in both the simulation and real-world scenarios,regardless of textile properties or initial conditions.展开更多
Owing to its unique ability to capture volumetric tomographic information with a single light flash,optoacoustic(OA)tomography has recently demonstrated ultrafast imaging speeds ultimately limited by the ultrasound ti...Owing to its unique ability to capture volumetric tomographic information with a single light flash,optoacoustic(OA)tomography has recently demonstrated ultrafast imaging speeds ultimately limited by the ultrasound time-of-flight.The method's scalability and the achievable spatial resolution are yet limited by the narrow bandwidth of piezo-composite arrays currently employed for OA signal detection.Here we report on the first implementation of high-density spherical array technology based on flexible polyvinylidene difluoride films featuring ultrawideband(0.3-40 MHz)sub mm^(2)area elements,thus enabling real-time multi-scale volumetric imaging with 22-35μm spatial resolution,superior image fidelity and over an order of magnitude signal-to-noise enhancement compared to piezo-composite equivalents.We further demonstrate five-dimensional(spectroscopic,time-resolved,volumetric)imaging capabilities by visualizing fast stimulus-evoked cerebral oxygenation changes in mice and performing real-time functional angiography of deep human micro-vasculature.The new technology thus leverages the true potential of OA for quantitative high-resolution visualization of rapid bio-dynamics across scales.展开更多
Catalyst-free growth of one-dimensional zinc oxide （ZnO） nanowires is reported. ZnO nanowires were synthesized on ZnO buffer layers deposited on various-oriented sapphire substrates. Syntheses of ZnO buffer layers a...Catalyst-free growth of one-dimensional zinc oxide （ZnO） nanowires is reported. ZnO nanowires were synthesized on ZnO buffer layers deposited on various-oriented sapphire substrates. Syntheses of ZnO buffer layers and nanowires were performed by ultraviolet pulsed-laser deposition. ZnO nanowire＇s number density was the lowest in the case of using m-cut sapphire substrates. ZnO nanowires grown on a-cut sapphire substrates had vertical alignment with distances of tens to hundreds of nanometers. On the other hand, ZnO nanowires grown on c-cut sapphire substrates had the biggest nucleation rate. The dependence of crystalline orientation of ZnO buffer layers on the orientation of sapphire substrates were investigated by electron back scatter diffraction measurement. From their results, the growth models of ZnO buffer layers were suggested and the variations in morphological properties ofZnO nanowires were discussed.展开更多
Rapid progress in the development of multispectral optoacoustic tomography techniques has enabled unprecedented insights into biological dynamics and molecular processes in vivo and noninvasively at penetration and sp...Rapid progress in the development of multispectral optoacoustic tomography techniques has enabled unprecedented insights into biological dynamics and molecular processes in vivo and noninvasively at penetration and spatiotemporal scales not covered by modern optical microscopy methods.Ultrasound imaging provides highly complementary information on elastic and functional tissue properties and further aids in enhancing optoacoustic image quality.We devised the first hybrid transmission–reflection optoacoustic ultrasound(TROPUS)small animal imaging platform that combines optoacoustic tomography with both reflection-and transmission-mode ultrasound computed tomography.The system features full-view cross-sectional tomographic imaging geometry for concomitant noninvasive mapping of the absorbed optical energy,acoustic reflectivity,speed of sound,and acoustic attenuation in whole live mice with submillimeter resolution and unrivaled image quality.Graphics-processing unit(GPU)-based algorithms employing spatial compounding and bent-ray-tracing iterative reconstruction were further developed to attain real-time rendering of ultrasound tomography images in the full-ring acquisition geometry.In vivo mouse imaging experiments revealed fine details on the organ parenchyma,vascularization,tissue reflectivity,density,and stiffness.We further used the speed of sound maps retrieved by the transmission ultrasound tomography to improve optoacoustic reconstructions via two-compartment modeling.The newly developed synergistic multimodal combination offers unmatched capabilities for imaging multiple tissue properties and biomarkers with high resolution,penetration,and contrast.展开更多
基金supported by the Third Level of Hangzhou 131 Young Talent Cultivation Plan Funding2018 Soft Science Research Project of Zhejiang Provincial Science and Technology Department Zhejiang Province Construction and participate in the“The Belt and Road”Technology Innovation Community Path Research(2018C35029)
文摘In this paper, both output-feedback iterative learning control(ILC) and repetitive learning control(RLC) schemes are proposed for trajectory tracking of nonlinear systems with state-dependent time-varying uncertainties. An iterative learning controller, together with a state observer and a fully-saturated learning mechanism, through Lyapunov-like synthesis, is designed to deal with time-varying parametric uncertainties. The estimations for outputs, instead of system outputs themselves, are applied to form the error equation, which helps to establish convergence of the system outputs to the desired ones. This method is then extended to repetitive learning controller design. The boundedness of all the signals in the closed-loop is guaranteed and asymptotic convergence of both the state estimation error and the tracking error is established in both cases of ILC and RLC. Numerical results are presented to verify the effectiveness of the proposed methods.
基金supported by the National Natural Science Foundation of China(61273200,61273152,61202111,61304052,51407088)the Science Foundation of Education Office of Shandong Province of China(ZR2011FM07,BS2015DX018)
文摘In complex environments, many distributed multiagent systems are described with the fractional-order dynamics.In this paper, containment control of fractional-order multiagent systems with multiple leader agents are studied. Firstly,the collaborative control of fractional-order multi-agent systems(FOMAS) with multiple leaders is analyzed in a directed network without delays. Then, by using Laplace transform and frequency domain theorem, containment consensus of networked FOMAS with time delays is investigated in an undirected network, and a critical value of delays is obtained to ensure the containment consensus of FOMAS. Finally, numerical simulations are shown to verify the results.
基金Project(61404122)supported by the National Natural Science Foundation of China
文摘The noise of closed loop micro-electromechanical systems(MEMS) capacitive accelerometer is treated as one of the significant performance specifications.Traditional optimization of noise performance often focuses on designing large capacitive sensitivity accelerometer and applying closed loop structure to shape total noise,but different noise sources in closed loop and their behaviors at low frequencies are seldom carefully studied,especially their behaviors with different electronic parameters.In this work,a thorough noise analysis is established focusing on the four noise sources transfer functions near 0 Hz with simplified electronic parameters in closed loop,and it is found that the total electronic noise equivalent acceleration varies differently at different frequency points,such that the noise spectrum shape at low frequencies can be altered from 1/f noise-like shape to flat spectrum shape.The bias instability changes as a consequence.With appropriate parameters settings,the 670 Hz resonant frequency accelerometer can reach resolution of 2.6 μg/(Hz)1/2 at 2 Hz and 6 μg bias instability,and 1300 Hz accelerometer can achieve 5μg/(Hz)1/2 at 2 Hz and 31 μg bias instability.Both accelerometers have flat spectrum profile from 2 Hz to 15 Hz.
文摘A short review for the existing various driving methods for belt conveyor was given, which include the analysis and comparison about the advantages, disadvantages and suitable application range of these methods. Based on this the vari-able-frequency-control(VFC) method for belt conveyor drive was fully discussed with focus on its application in medium-high voltage range. The principle of Neutral Point Clamped (NPC) Three-Level Inverter using high-voltage IGBTs together with the control strategy of rotor field-oriented vector control for induction motor drive were illustrated.
文摘The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of intrinsically safe circuit, which has two working modes: continuous inductive current (CCM — continuous conduction mode) and dis- crete inductance current (DCM — discontinuous conduction mode). The operating state of the continuous inductive current mode is analyzed in detail and the energy of discharge spark in various operating modes is discussed. The total energy will decrease with the increase of switch frequency, in a switching cycle; the discharge spark energy has a maxi- mum and a minimum value. Therefore, the Buck converter has smaller discharge spark energy than the linear power circuit and the switch type of intrinsically safe circuit can enhance the output power and the conversion efficiency of the intrinsically safe power.
基金This work was supported by the National Natural Science Foundation of China(31671116,31761163005,31800881,and 91132306)the International Big Science Program Cultivation Project of Chinese Academy of Sciences(172644KYS820170004)+3 种基金the External Cooperation Program of the Chinese Academy of Sciences(172644KYSB20160057)Science and Technology Program of Guangzhou Municipality(202007030001)the Key-Area Research and Development Program of Guangdong Province(2018B030331001 and 2018B03033600)Shenzhen Government Basic Research Grants(JCYJ20200109115405930 and JCYJ20200109150717745).
文摘A strong animal survival instinct is to approach objects and situations that are of benefit and to avoid risk.In humans,a large proportion of mental disorders are accompanied by impairments in risk avoidance.One of the most important genes involved in mental disorders is disrupted-in-schizophrenia-1(DISC1),and animal models in which this gene has some level of dysfunction show emotion-related impairments.However,it is not known whether DISC1 mouse models have an impairment in avoiding potential risks.In the present study,we used DISC1-N terminal truncation(DISC1-N^(TM))mice to investigate risk avoidance and found that these mice were impaired in risk avoidance on the elevated plus maze(EPM)and showed reduced social preference in a three-chamber social interaction test.Following EPM tests,c-Fos expression levels indicated that the nucleus accumbens(NAc)was associated with risk-avoidance behavior in DISC1-N^(TM)mice.In addition,in vivo electrophysiological recordings following tamoxifen administration showed that the firing rates of fast-spiking neurons(FS)in the NAc were significantly lower in DISC1-N^(TM)mice than in wild-type(WT)mice.In addition,in vitro patch clamp recording revealed that the frequency of action potentials stimulated by current injection was lower in parvalbumin(PV)neurons in the NAc of DISC1-N^(TM)mice than in WT controls.The impairment of risk avoidance in DISC1-N^(TM)mice was rescued using optogenetic tools that activated NAcPV neurons.Finally,inhibition of the activity of NAcPV neurons in PV-Cre mice mimicked the risk-avoidance impairment found in DISC1-N^(TM)mice during tests on the elevated zero maze.Taken together,our findings confirm an impairment in risk avoidance in DISC1-N^(TM)mice and suggest that reduced excitability of NAc^(PV) neurons is responsible.
基金Qinglan Project of Jiangsu Province of China,Grant/Award Number:BK20180820National Natural Science Foundation of China,Grant/Award Numbers:12271255,61701243,71771125,72271126,12227808+2 种基金Major Projects of Natural Sciences of University in Jiangsu Province of China,Grant/Award Numbers:21KJA630001,22KJA630001Postgraduate Research and Practice Innovation Program of Jiangsu Province,Grant/Award Number:KYCX23_2343supported by the National Natural Science Foundation of China(no.72271126,12271255,61701243,71771125,12227808)。
文摘As human‐machine interaction(HMI)in healthcare continues to evolve,the issue of trust in HMI in healthcare has been raised and explored.It is critical for the development and safety of healthcare that humans have proper trust in medical machines.Intelligent machines that have applied machine learning(ML)technologies continue to penetrate deeper into the medical environment,which also places higher demands on intelligent healthcare.In order to make machines play a role in HMI in healthcare more effectively and make human‐machine cooperation more harmonious,the authors need to build good humanmachine trust(HMT)in healthcare.This article provides a systematic overview of the prominent research on ML and HMT in healthcare.In addition,this study explores and analyses ML and three important factors that influence HMT in healthcare,and then proposes a HMT model in healthcare.Finally,general trends are summarised and issues to consider addressing in future research on HMT in healthcare are identified.
基金supported by the Swiss National Science Foundation via an SNF Sinergia Grant(grant number CRSII5-180367).
文摘Biodegradable magnesium is a highly desired material for fracture fixation implants because of its good me-chanical properties and ability to completely dissolve in the body over time,eliminating the need for a secondary surgery to remove the implant.Despite extensive research on these materials,there remains a dearth of infor-mation regarding critical factors that affect implant performance in clinical applications,such as the in vivo pH and mechanical loading conditions.We developed a measurement system with implantable strain,temperature,pH and motion sensors to characterize magnesium and titanium plates,fixating bilateral zygomatic arch osteotomies in three Swiss alpine sheep for eight weeks.pH 1-2 mm above titanium plates was 6.6±0.4,while for magnesium plates it was slightly elevated to 7.4±0.8.Strains on magnesium plates were higher than on titanium plates,possibly due to the lower Young’s modulus of magnesium.One magnesium plate experienced excessive loading,which led to plate failure within 31 h.This is,to our knowledge,the first in vivo strain,temperature,and pH data recorded for magnesium implants used for fracture fixation.These results provide insight into magnesium degradation and its influence on the in vivo environment,and may help to improve material and implant design for future clinical applications.
基金funded by the European Union under the 7th Framework Program grant agreement no 605162(BERTI)the European Union’s Horizon 2020 research and innovation programme under grant agreement no.687866(INNODERM)and no.862811(RSENSE)+3 种基金the Deutsche Forschungsgemeinschaft(DFG)as part of the CRC 1123(Z1)funding from the European Commission grant agreement No 801347(SENSITIVE)Spanish Ministry of Economy and Competitiveness(MINECO)Grant FIS2016-77892-Rthe Alexander von Humboldt Postdoctoral Fellowship program.
文摘Optoacoustic signals behave nonlinearly at light fluences above a few mJ/cm^(2),which may affect the interpretation and quantification of measurements.It has been proposed that optoacoustic nonlinearity arises from the heat-induced formation of nanobubbles or changes in local thermo-physical parameters.However,such explanations are only valid at much higher fluences than typically used in biomedical optoacoustic imaging(>20 mJ/cm^(2))or in the presence of materials with high absorption coefficients such as gold nanoparticles.We propose herein that electromagnetic permittivity changes in response to photon absorption are major source of optoacoustic signal nonlinearity at low fluences.We provide theoretical and experimental evidence that supports this postulation and show that optoacoustic pressure responses due to permittivity changes,which are function of thermally excited third-order nonlinear susceptibility,can explain the nonlinear behavior of the optoacoustic signal.Since different materials exhibit different thermally excited third-order nonlinear susceptibility,this property could function as a new contrast mechanism that can identify the sensitivity of a substance’s dielectric constant to photon-induced temperature changes.Consequently,we propose an imaging method based on nonlinear optoacoustic signals that exploits this newly identified contrast mechanism.These findings may have far-reaching implications for improving the accuracy of optoacoustics and utilizing the proposed new contrast mechanism would advance our understanding of cellular and tissue functionality.
基金Project supported by the National Natural Science Foundation of China (Nos. 30270775 and 30370823) and the DoctorResearch Foundation of the Ministry of Education of China (No. 20030019012)
文摘For many years a soil water content sensor with low cost, reliability and sufficient accuracy has been desirable. Thus, an improved measurement method based on the frequency domain (FD) principle for determining soil water content was considered. Unlike other measurement principles, a new measurable index, η, which was independent of the output impedance and the amplitude of the oscillator while relying on the electrical impedance of a multi-pin probe, was pro- posed. Moreover, a model for processing the impedance of the multi-pin soil probe was developed, and several important electrical parameters for establishing their operating ranges applicable to this probe were evaluated. In order to confirm the theoretical analysis, an experiment was conducted with a 4-pin probe. Using the developed model, the relationship between the proposed index η and soil volumetric water content was shown to be linear (R2 = 0.9921). Thus, as the measurable index, η seemed satisfactory.
基金This research was funded by the National Nature Sciences Foundation of China(Grant No.42250410321).
文摘Missing value is one of the main factors that cause dirty data.Without high-quality data,there will be no reliable analysis results and precise decision-making.Therefore,the data warehouse needs to integrate high-quality data consistently.In the power system,the electricity consumption data of some large users cannot be normally collected resulting in missing data,which affects the calculation of power supply and eventually leads to a large error in the daily power line loss rate.For the problem of missing electricity consumption data,this study proposes a group method of data handling(GMDH)based data interpolation method in distribution power networks and applies it in the analysis of actually collected electricity data.First,the dependent and independent variables are defined from the original data,and the upper and lower limits of missing values are determined according to prior knowledge or existing data information.All missing data are randomly interpolated within the upper and lower limits.Then,the GMDH network is established to obtain the optimal complexity model,which is used to predict the missing data to replace the last imputed electricity consumption data.At last,this process is implemented iteratively until the missing values do not change.Under a relatively small noise level(α=0.25),the proposed approach achieves a maximum error of no more than 0.605%.Experimental findings demonstrate the efficacy and feasibility of the proposed approach,which realizes the transformation from incomplete data to complete data.Also,this proposed data interpolation approach provides a strong basis for the electricity theft diagnosis and metering fault analysis of electricity enterprises.
基金partially supported by the European Research Council Consolidator grant ERC-2015-CoG-682379funded by the University Foundation Fellowship of the Technical University of Munich.
文摘Despite the importance of placental function in embryonic development,it remains poorly understood and challenging to characterize,primarily due to the lack of non-invasive imaging tools capable of monitoring placental and foetal oxygenation and perfusion parameters during pregnancy.We developed an optoacoustic tomography approach for real-time imaging through entire ~4 cm cross-sections of pregnant mice.Functional changes in both maternal and embryo regions were studied at different gestation days when subjected to an oxygen breathing challenge and perfusion with indocyanine green.Structural phenotyping of the cross-sectional scans highlighted different internal organs,whereas multi-wavelength acquisitions enabled non-invasive label-free spectroscopic assessment of blood-oxygenation parameters in foeto-placental regions,rendering a strong correlation with the amount of oxygen administered.Likewise,the placental function in protecting the embryo from extrinsically administered agents was substantiated.The proposed methodology may potentially further serve as a probing mechanism to appraise embryo development during pregnancy in the clinical setting.
基金supported in part by the program for "Industrial Io T and Emergency Collaboration" Innovative Research Team in CUMT (No.2020ZY002)in part by the Postgraduate Research&Practice Innovation Program of Jiangsu Province,2021WLKXJ054Postgraduate Research&Practice Innovation Program of China University of Mining and Technology,KYCX21_2242
文摘Underwater magnetic induction(MI)-assisted acoustic cooperative multiple-input-multipleoutput(MIMO) has been recently proposed as a promising technique for underwater wireless sensor networks(UWSNs).For the more,the energy utilization of energy-constrained sensor nodes is one of the key issues in UWSNs,and it relates to the network lifetime.In this paper,we present an energy-efficient data collection for underwater MI-assisted acoustic cooperative MIMO wireless sensor networks(WSNs),including the formation of cooperative MIMO and relay link establishment.Firstly,the cooperative MIMO is formed by considering its expected transmission range and the energy balance of nodes with it.Particularly,from the perspective of the node’s energy consumption,the expected cooperative MIMO size and the selection of master node(MN) are proposed.Sequentially,to improve the coverage of the networks and prolong the network lifetime,relay links are established by relay selection algorithm that using matching theory.Finally,the simulation results show that the proposed data collection improves its efficiency,reduces the energy consumption of the master node,improves the networks’ coverage,and extends the network lifetime.
基金funding from the Swiss National Science Foundation(310030_192757)the US National Institutes of Health(RF1-NS126102)+1 种基金Bjoern Menze is supported through a Helmut-Horten-Professorship for Biomedical Informatics by the Helmut Horten Foundation.Bastian Wittmann is supported through the Helmut Horten Foundation.Susanne Wegener acknowledges funding from the Swiss National Science Foundation(310030_200703)the UZH CRPP stroke.The authors appreciate the help of Paul-James Marchand with setting up the OCM system and the fruitful discussions.
文摘Understanding the morphology and function of large-scale cerebrovascular networks is crucial for studying brain health and disease.However,reconciling the demands for imaging on a broad scale with the precision of highresolution volumetric microscopy has been a persistent challenge.In this study,we introduce Bessel beam optical coherence microscopy with an extended focus to capture the full cortical vascular hierarchy in mice over 1000×1000×360μm^(3)field-of-view at capillary level resolution.The post-processing pipeline leverages a supervised deep learning approach for precise 3D segmentation of high-resolution angiograms,hence permitting reliable examination of microvascular structures at multiple spatial scales.Coupled with high-sensitivity Doppler optical coherence tomography,our method enables the computation of both axial and transverse blood velocity components as well as vessel-specific blood flow direction,facilitating a detailed assessment of morpho-functional characteristics across all vessel dimensions.Through graph-based analysis,we deliver insights into vascular connectivity,all the way from individual capillaries to broader network interactions,a task traditionally challenging for in vivo studies.The new imaging and analysis framework extends the frontiers of research into cerebrovascular function and neurovascular pathologies.
基金support from the UZH Postdoc Grant.Dr.Pavel Subochev acknowledges support by RSF project 19-75-10055(development of needle PVDF-TrFE US sensor)support by Center of Excellence“Center of Photonics”funded by the Ministry of Science and Higher Education of the Russian Federation,Contract No.075-15-2022-316(measurements of sensitivity and NEP of needle PVDF-TrFE US sensor).
文摘A wideband sensitive needle ultrasound sensor based on a polarized PVDF-TrFE copolymer piezoelectric film has been developed,which is capable of providing a noise equivalent pressure of 14 Pa and a uniform frequency response ranging from 1 to 25 MHz.Its high sensitivity(1.6μV∕Pa)and compact size were achieved by capitalizing on the large electromechanical coupling coefficient of PVDF-TrFE and minimizing parasitic capacitance in a two-stage amplifier structure.The detection sensitivity of the newly designed sensor outperformed commercially available hydrophones with an equivalent sensing element area by a factor of 9.The sensor has been successfully integrated into a light scanning optoacoustic microscopy(OAM)system with a limited working space.Submicrometer resolution images were subsequently attained from living mice without employing signal averaging.The miniature sensor design can readily be integrated into various OAM systems and further facilitate multimodal imaging system implementations.
基金funding support from the Swiss National Science Foundation(310030_192757).
文摘High-speed volumetric optoacoustic tomography(VOT)offers powerful means for noninvasive,detailed visualization of rapid cardiac dynamics in mice.However,current implementations suffer from non-uniform light delivery into the thoracic area,which results in diminished penetration depth,limited field-of-view,and compromised quantification abilities.In this work,we devised a new VOT approach featuring hexagonally-shaped light delivery optimized for whole-heart imaging and an expedited imaging speed of 200 volumes per second using a custom-made spherical array transducer.The enhanced imaging performance was confirmed with calibration phantoms and noninvasive imaging of the murine heart.We capitalized on the reduced hemoglobin absorption in the second near-infrared(NIR-II)spectral window to mitigate the strong light attenuation by whole blood within the cardiac chambers while further employing copper sulfide nanoparticles featuring a strong NIR-II absorption to quantify cardiac functional parameters across the entire heart in vivo.The new approach can thus facilitate the monitoring of cardiac abnormalities and assessment of therapeutic interventions.
文摘Deformable manipulation has attracted a lot of attention in the field of robotics,especially in medical applications.However,manipulating deformable objects faces various challenges,mainly including their complex dynamic properties and unpredictable nonlinear deformations.It is difficult to provide a basis for deformable object measurements without effective control methods that provide intelligent and accurate position control,and this research also provides a premise for deformable object measurements.To address these issues,this paper proposes an online iterative perception policy(IPP)method,which does not require large-scale deep network training.This method is able to perceive transformations through an iterative process,and achieve efficient and accurate control of deformable objects.Extensive experiments in the simulation environment and the real scene are conducted to validate the effectiveness and superiority of the proposed method,as well as to compare with advanced algorithms(linear–quadratic regulator(LQR),sliding mode control(SMC),model predictive control(MPC),and heuristic).The experimental results reveal that IPP outperforms other approaches in terms of convergence,stability,robustness and flexibility in both the simulation and real-world scenarios,regardless of textile properties or initial conditions.
基金supported by the Swiss National Science Foundation(310030_192757)the European Research Council(ERC-2015-CoG-682379)+2 种基金The development of the ultra-wideband ultrasonic antenna and the in vivo optoacoustic experiments were supported by the grants from the Russian Science Foundation(18-45-06006)the Helmholtz Association(HRSF-0020)The development of numerical algorithms for enhancement of angiographic optoacoustic images was partially supported by the grant from the Russian Science Foundation(19-75-10055)。
文摘Owing to its unique ability to capture volumetric tomographic information with a single light flash,optoacoustic(OA)tomography has recently demonstrated ultrafast imaging speeds ultimately limited by the ultrasound time-of-flight.The method's scalability and the achievable spatial resolution are yet limited by the narrow bandwidth of piezo-composite arrays currently employed for OA signal detection.Here we report on the first implementation of high-density spherical array technology based on flexible polyvinylidene difluoride films featuring ultrawideband(0.3-40 MHz)sub mm^(2)area elements,thus enabling real-time multi-scale volumetric imaging with 22-35μm spatial resolution,superior image fidelity and over an order of magnitude signal-to-noise enhancement compared to piezo-composite equivalents.We further demonstrate five-dimensional(spectroscopic,time-resolved,volumetric)imaging capabilities by visualizing fast stimulus-evoked cerebral oxygenation changes in mice and performing real-time functional angiography of deep human micro-vasculature.The new technology thus leverages the true potential of OA for quantitative high-resolution visualization of rapid bio-dynamics across scales.
文摘Catalyst-free growth of one-dimensional zinc oxide （ZnO） nanowires is reported. ZnO nanowires were synthesized on ZnO buffer layers deposited on various-oriented sapphire substrates. Syntheses of ZnO buffer layers and nanowires were performed by ultraviolet pulsed-laser deposition. ZnO nanowire＇s number density was the lowest in the case of using m-cut sapphire substrates. ZnO nanowires grown on a-cut sapphire substrates had vertical alignment with distances of tens to hundreds of nanometers. On the other hand, ZnO nanowires grown on c-cut sapphire substrates had the biggest nucleation rate. The dependence of crystalline orientation of ZnO buffer layers on the orientation of sapphire substrates were investigated by electron back scatter diffraction measurement. From their results, the growth models of ZnO buffer layers were suggested and the variations in morphological properties ofZnO nanowires were discussed.
基金the European Research Council under grant ERC-2015-CoG-682379German Research Foundation Grant RA1848/5-1+2 种基金partial support from the Spanish Government(FPA2015-65035-P,RTC-2015-3772-1)Comunidad de Madrid(S2013/MIT-3024 TOPUS-CM,B2017/BMD-3888 PRONTO-CM)European Regional Funds.
文摘Rapid progress in the development of multispectral optoacoustic tomography techniques has enabled unprecedented insights into biological dynamics and molecular processes in vivo and noninvasively at penetration and spatiotemporal scales not covered by modern optical microscopy methods.Ultrasound imaging provides highly complementary information on elastic and functional tissue properties and further aids in enhancing optoacoustic image quality.We devised the first hybrid transmission–reflection optoacoustic ultrasound(TROPUS)small animal imaging platform that combines optoacoustic tomography with both reflection-and transmission-mode ultrasound computed tomography.The system features full-view cross-sectional tomographic imaging geometry for concomitant noninvasive mapping of the absorbed optical energy,acoustic reflectivity,speed of sound,and acoustic attenuation in whole live mice with submillimeter resolution and unrivaled image quality.Graphics-processing unit(GPU)-based algorithms employing spatial compounding and bent-ray-tracing iterative reconstruction were further developed to attain real-time rendering of ultrasound tomography images in the full-ring acquisition geometry.In vivo mouse imaging experiments revealed fine details on the organ parenchyma,vascularization,tissue reflectivity,density,and stiffness.We further used the speed of sound maps retrieved by the transmission ultrasound tomography to improve optoacoustic reconstructions via two-compartment modeling.The newly developed synergistic multimodal combination offers unmatched capabilities for imaging multiple tissue properties and biomarkers with high resolution,penetration,and contrast.
