The 22.2 multichannel system and its simplified system with 10-channel and 8-channel have been proposed, which brings people 3 D listening experience. But these systems could only accurately reproduce sound field at a...The 22.2 multichannel system and its simplified system with 10-channel and 8-channel have been proposed, which brings people 3 D listening experience. But these systems could only accurately reproduce sound field at a central listening point which is called sweetspot. In order to solve this problem, this paper proposes a non-central zone sound field reproduction method PVMDZ（particle velocity matching between different zones） based on the physical property of sound. The proposed method matches the physical property of sound of non-central zone in reconstructed sound field with that of central zone in original sound field, so the reproduced non-central zone would produce the same listening experience as the central zone of the original system does. By experiments, we compare the performances of the proposed method with the traditional one, and the result proves that the sound field error of proposed method is reduced.展开更多
The two-phase flow instabilities observed in through parallel multichannel can be classified into three types,of which only one is intrinsic to parallel multichannel systems.The intrinsic instabilities observed in par...The two-phase flow instabilities observed in through parallel multichannel can be classified into three types,of which only one is intrinsic to parallel multichannel systems.The intrinsic instabilities observed in parallel multichannel system have been studied experimentally.The stable boundary of the flow in such a parallel-channel system are sought,and the nature of inlet flow oscillation in the unstable region has been examined experimentally under various conditions of inlet velocity,heat flux,liquid temperature,cross section of channel and entrance throttling.The results show that parallel multichannel system possess a characteristic oscillation that is quite independent of the magnitude and duration of the initial disturbance,and the stable boundary is influenced by the characteristic frequency of the system as well as by the exit quality when this is low,and upon raising the exit quality and reducing the characteristic frequency,the system increases its instability,and entrance throttling effectively contributes to stabilization of the system.展开更多
The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high...The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high vertical and horizontal resolution.However,the quality of deep-towed seismic imaging hinges on accurate source-receiver positioning information.In light of existing technical problems,we propose a novel array geometry inversion method tailored for high-resolution deep-towed multichannel seismic exploration systems.This method is independent of the attitude and depth sensors along a deep-towed seismic streamer,accounting for variations in seawater velocity and seabed slope angle.Our approach decomposes the towed line array into multiline segments and characterizes its geometric shape using the line segment distance and pitch angle.Introducing optimization parameters for seawater velocity and seabed slope angle,we establish an objective function based on the model,yielding results that align with objective reality.Employing the particle swarm optimization algorithm enables synchronous acquisition of optimized inversion results for array geometry and seawater velocity.Experimental validation using theoretical models and practical data verifies that our approach effectively enhances source and receiver positioning inversion accuracy.The algorithm exhibits robust stability and reliability,addressing uncertainties in seismic traveltime picking and complex seabed topography conditions.展开更多
As seismic signals propagate underground,the subsurface media absorb high-frequency components,decreasing seismic resolution and limiting the identification and characterization of thin reservoirs.To address the limit...As seismic signals propagate underground,the subsurface media absorb high-frequency components,decreasing seismic resolution and limiting the identification and characterization of thin reservoirs.To address the limitation,this paper proposes a multichannel spectral fitting(MSF)method.The MSF method aims to enhance seismic resolution by considering the spectral characteristics and the correlations between adjacent seismic traces.The key to the MSF method involves utilizing the amplitude spectrum of the attenuated Ricker wavelet to construct an objective function for spectral fitting,leading to improved seismic resolution.Furthermore,the MSF method establishes the correlation between adjacent seismic traces as a constraint to stably solve the target parameters based on the entire seismic spectrum,which helps obtain horizontally consistent and more realistic seismic signals.Synthetic and field seismic examples demonstrate that the proposed method not only provides higher-resolution seismic signals but also reveals more fine details of thin reservoirs compared to the time-variant spectral whitening method.It is concluded that the MSF method is a promising tool for seismic signal processing.展开更多
Traditional deconvolution methods based on single-channel inversion do not consider the spatial structural relation between channels,and hence,they yield high-resolution results with the existing transverse inconsiste...Traditional deconvolution methods based on single-channel inversion do not consider the spatial structural relation between channels,and hence,they yield high-resolution results with the existing transverse inconsistency or discontinuity.Therefore,in this study,the local dip angle was used to obtain the structural information and construct the spatial structurally constraint operator.This operator is then introduced into multichannel deconvolution as a regularization operator to improve the resolution and maintain the transverse continuity of seismic data.Model tests and actual seismic data processing have demonstrated the effectiveness and practicability of this method.展开更多
Normally, Data acquisition (DAQ) is used to acquire the signals from different devices like sensors, transducers, actuators etc. The data acquisition is also used to analyze the signals, digitizing the signals and acq...Normally, Data acquisition (DAQ) is used to acquire the signals from different devices like sensors, transducers, actuators etc. The data acquisition is also used to analyze the signals, digitizing the signals and acquiring the signals from different inputs. The main drawbacks in data acquisition system are data storage, hardware size and remote monitoring. The System-on-Chip Field Programmable Gate Array (SoC-FPGA) is used in the proposed system in the aim to reduce the hardware and memory size. Further to provide remote monitoring with Ethernet/Wi-Fi, the Network Control Module (NCM) is integrated with Data acquisition and processing module for the communication between the systems. This developed system achieves high resolution with memory reduction, reduced hardware size, fast remote monitoring and control. It is used for real time processing in DAQ and signal processing. For fault tolerance and portability, the full system reconfigurability based FPGA acts as the best solution and the system can be reused with different configurations. The control of data acquisition and the subsequent management of data are coded in LabVIEW. LabVIEW tool is used to design and develop a four-channel Data Acquisition and Processing (DAQP) unit. National Instruments Data Acquisition (NIDAQ) and National Instruments Field Programmable Gate Array (NIFPGA) are used to test and implement the design for real time processing. This is designed to provide high accuracy, storage and portability.展开更多
Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electr...Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical application.Herein,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance PIBs.The CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat treatment.The porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge process.In addition,numerous pores facilitated the transport of electrons and ions.Accordingly,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).展开更多
Background A large number of robots have put forward the new requirements for human robot interaction.One of the problems in human-swarm robot interaction is how to naturally achieve an efficient and accurate interact...Background A large number of robots have put forward the new requirements for human robot interaction.One of the problems in human-swarm robot interaction is how to naturally achieve an efficient and accurate interaction between humans and swarm robot systems.To address this,this paper proposes a new type of human-swarm natural interaction system.Methods Through the cooperation between three-dimensional(3D)gesture interaction channel and natural language instruction channel,a natural and efficient interaction between a human and swarm robots is achieved.Results First,A 3D lasso technology realizes a batch-picking interaction of swarm robots through oriented bounding boxes.Second,control instruction labels for swarm-oriented robots are defined.The instruction label is integrated with the 3D gesture and natural language through instruction label filling.Finally,the understanding of natural language instructions is realized through a text classifier based on the maximum entropy model.A head-mounted augmented reality display device is used as a visual feedback channel.Conclusions The experiments on selecting robots verify the feasibility and availability of the system.展开更多
The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian la...The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.展开更多
With the constantly changing engineering construction sector,the detection accuracy of conventional electrical resistivity tomography(ERT)is no longer sufficient.A multichannel electrode design(MERT)-based ERT is intr...With the constantly changing engineering construction sector,the detection accuracy of conventional electrical resistivity tomography(ERT)is no longer sufficient.A multichannel electrode design(MERT)-based ERT is introduced in this paper to address the growing need for resolution.The imaging accuracy of the ERT method is improved through the collection of apparent resistivity data in various directions by measuring the potential diff erence between diff erent channels.Numerical simulation results of the inclined high-resistivity anomaly model reveal that MERT is a precise representation of the shape,inclined direction,and buried depth of the anomaly,with thoroughfare M2N2 producing the most precise forward and inverse results.Based on the analysis results of the model resolution matrix,when the buried depth of power supply points and the gap between potential acquisition points are 30%-90%and 30%-60%of the electrode distance,respectively,the MERT approach yields superior detection outcomes.The detection eff ect of the MERT method on anomalous bodies with diff erent burial depths under the optimal parameters also indicates that the MERT method can obtain richer potential change information with higher resolution in deep areas compared to the ERT method.With the implementation of the MERT approach,the scope of applications for ERT is expanded,the accuracy of ERT detection is increased,and the progress of near-surface fine detection is positively infl uenced.展开更多
The balancing of the electrochemical performance,mechanical stability,and processing technology for applying supercapacitors to flexible and wearable electronics continues to encounter severe challenges.Herein,we prep...The balancing of the electrochemical performance,mechanical stability,and processing technology for applying supercapacitors to flexible and wearable electronics continues to encounter severe challenges.Herein,we prepare Ni-Co-Mn hydroxide electrodes with a threedimensional multichannel structure via a simple hydrothermal method.These are constructed using vertically contiguous nano sheets with a uniform thickness and rough surface.The electrodes can provide numerous electroactive sites and accelerate the transmission of electrolyte ions.The relationship between the structure and electrochemical performances is verified by experiments and theoretical calculations.Two-dimensional(2D)planar and one-dimensional(1D)fiber electrodes are prepared using a flexible carbon cloth(CC)and carbon fiber(CF),respectively,as substrates.The assembled quasi-solid-state flexible asymmetric supercapacitor(FASC)with a twodimensional sandwich structure using NiCoMn-OH/CC as the electrode achieves a remarkable energy density of73.8 Wh·kg^(-1)at a power density of 1.03 kW·kg^(-1).The quasi-solid-state FASC with a 1D linear structure using NiCoMn-OH/CF as the electrode also attains a high energy density(12.9 Wh·kg^(-1)at a power density of0.75 W·kg^(-1)).Moreover,the electrochemical performances of the NiCoMn/CC//AC/CC and NiCoMn/CF//AC/CF FASCs are not disturbed at different bending angles(0°,45°,90°,135°and 180°),This indicates the superior flexibility of the devices.We also assemble a self-powered energy-harvesting storage system by integrating FASCs and commercial solar cells to verify its practicability.It displays sustainable development potential for energy storage.展开更多
Zn metal anodes are usually subject to grave dendrite growth during platting/stripping,which dramatically curtails the lifespan of aqueous Zn-ion batteries and capacitors.To address above problems,in our work,a novel ...Zn metal anodes are usually subject to grave dendrite growth during platting/stripping,which dramatically curtails the lifespan of aqueous Zn-ion batteries and capacitors.To address above problems,in our work,a novel phosphorus-functionalized multichannel carbon interlayer was designed and covered on Zn anodes.The results demonstrated that the multichannel structure combined with the three-dimensional meshy skeleton can provide more sufficient space for Zn deposition,thereby effectively inhibiting the growth of zinc dendrites.Meanwhile,theoretical calculations also confirmed that the P-C and P=O functional groups from phosphorus-functionalized multichannel carbon interlayer have the decisive influence in reducing the zinc nucleation potential and depositing uniformly zinc.Concretely,the symmetrical battery assembled with phosphorus-functionalized multichannel carbon interlayer-covered Zn anodes possessed a long lifetime of 3300 h at 2 mA cm^(-2)with 1 mAh cm^(-2).Furthermore,the full cell with activated carbon cathodes exhibited a high specific capacity of 80.5 mAh g^(-1)and outstanding cycling stability without capacity decay after 15000 cycles at a high current density of 5 A g^(-1).The superior electrochemical performance exceeded that of most reported papers.Consequently,our synthesized zincophilic interlayer with the unique structure has superior prospects for application in stabilizing zinc anodes and prolonging the lifespan of batteries.展开更多
Distributed fiber gratings exhibit outstanding capabilities in achieving a wide spectral response through the superimposition of gratings with different periods in the fiber core.This significantly broadens the design...Distributed fiber gratings exhibit outstanding capabilities in achieving a wide spectral response through the superimposition of gratings with different periods in the fiber core.This significantly broadens the design flexibility and potential applications of fiber gratings.However,as photons pass through gratings with varying periods in sequence,which not only inevitably existing signal crosstalk but also poses challenges for integrating.In this study,a three-dimensional(3D)four-channel filter is proposed and realized in fiber-compatible materials using femtosecond laser writing.The filter consists of a 3D beam splitter and four parallel different-period Bragg waveguide gratings(WGs).By designing grating periods in each path,parallel filtering and reflection at multiple designed wavelengths are achieved compactly with 50 nm spectrum spacing within 1450-1600 nm wavelengths.The four-channel filter entire measures 15.5 mm×1 mm×1 mm(the highest integration of distributed fiber gratings reported so far).Our technique will augment the laser fabrication technology for 3D integrated photonic devices and serve as a powerful and generalized solution for highly integrated in-situ measurement and multi-parameter decoupled sensing.展开更多
涡桨飞机座舱的主动噪声控制系统普遍采用传统的多通道滤波x最小均方(multichannel filtered-x least mean square,简称McFxLMS)算法,该算法的计算量随着通道数的增加而激增,严重影响控制效果。针对该问题,基于连续局部迭代-McFxLMS(seq...涡桨飞机座舱的主动噪声控制系统普遍采用传统的多通道滤波x最小均方(multichannel filtered-x least mean square,简称McFxLMS)算法,该算法的计算量随着通道数的增加而激增,严重影响控制效果。针对该问题,基于连续局部迭代-McFxLMS(sequential partial update-McFxLMS,简称SPU-McFxLMS)算法,开发了多通道主动噪声控制系统。SPU-McFxLMS算法通过更新部分滤波器权值,在保证收敛精度的同时能够显著降低计算复杂度。首先,对比分析了传统McFxLMS算法与SPU-McFxLMS算法的原理差异,通过理论推导证明其计算效率提升特性;其次,建立了算法仿真模型,通过仿真验证了理论分析结果;最后,基于SOM-TL6678核心板开发了16通道的主动噪声控制系统,并搭建飞机座舱地面模拟实验平台进行实验。结果表明,该系统在108 Hz和216 Hz双频噪声场景下,各位置的平均降噪量能够达到10 dB以上。展开更多
复杂环境如汽车车厢内路噪的有源噪声控制(Active Noise Control,ANC)通常依赖大量传感器来获得有效的噪声控制性能,使应用传统自适应算法的收敛速度缓慢且计算量较大.针对这一问题,在频域滤波参考最小均方(Frequency Domain Filtered-x...复杂环境如汽车车厢内路噪的有源噪声控制(Active Noise Control,ANC)通常依赖大量传感器来获得有效的噪声控制性能,使应用传统自适应算法的收敛速度缓慢且计算量较大.针对这一问题,在频域滤波参考最小均方(Frequency Domain Filtered-x Least Mean Square,FDFxLMS)算法的基础上提出了多迭代预处理正则化频域滤波参考最小均方(Multi-Iterative Pre-Regularized Frequency Domain Filtered-x Least Mean Square,MIPR-FDFxLMS)算法,该算法的多迭代策略提升了算法收敛速度并保持较高的计算效率,预处理的正则化因子改进方法保证了算法的稳定收敛.基于实测汽车道路噪声数据的仿真结果表明,与传统自适应算法相比,提出的MIPR-FDFxLMS算法在收敛速度方面具有明显优势,展示了其在实际路噪控制系统中的应用前景.展开更多
A multichannel matching pursuit（MMP）algorithm is proposed to decompose the one-dimensional multichannel non-stationary magnetoencephalography（MEG）signal at a single-trial level.The single-channel matching pursuit...A multichannel matching pursuit（MMP）algorithm is proposed to decompose the one-dimensional multichannel non-stationary magnetoencephalography（MEG）signal at a single-trial level.The single-channel matching pursuit（MP）linearly decomposes the signal into a set of Gabor atoms,which are adaptively chosen from an overcomplete dictionary with good time-frequency characters.The MMP is the extension of the MP,which represents multichannel signals using linear combination of Gabor atoms with the same occurrence,frequency,phase,and time width,but varying amplitude in all channels.The results demonstrate that the MMP can optimally reconstruct the original signal and automatically remove artifact noises.Moreover,the coherence between the 3D source reconstruction and the prior knowledge of psychology further suggests that the MMP is effective in MEG single-trial processing.展开更多
Recently,Luolai Group released its Q12025 quarterly report.As a leading Chinese home textile enterprise listed on the Shenzhen Stock Exchange in 2009,the company covers the research,design,production,and sales of home...Recently,Luolai Group released its Q12025 quarterly report.As a leading Chinese home textile enterprise listed on the Shenzhen Stock Exchange in 2009,the company covers the research,design,production,and sales of home textile products,and has multiple brands covering different consumer markets.It has expanded its online and offline comprehensive multichannel sales system and is committed to creating a win-win home furnishings and textile industry ecosystem.展开更多
BACKGROUND Gastroesophageal reflux disease has been shown to contribute to allograft injury and rejection outcomes in lung transplantation through a proposed mechanism of aspiration,inflammation,and allograft injury.T...BACKGROUND Gastroesophageal reflux disease has been shown to contribute to allograft injury and rejection outcomes in lung transplantation through a proposed mechanism of aspiration,inflammation,and allograft injury.The value of pre-transplant reflux testing in predicting reduction in pulmonary function after lung transplantation is unclear.We hypothesized that increased reflux burden on pre-transplant reflux testing is associated with pulmonary function decline following lung transplant.AIM To assess the relationship between pre-transplant measures of reflux and pulmonary function decline in lung transplant recipients.METHODS This was a retrospective cohort study of lung transplant recipients who underwent pre-transplant reflux testing with 24-hour pH-impedance off acid suppression at a tertiary center in 2007-2016.Patients with pre-transplant fundoplication were excluded.Time-to-event analysis was performed using Cox proportional hazards models to assess associations between reflux measures and reduction in forced expiratory volume in 1 second(FEV1)of≥20%post-transplant.Patients not meeting endpoint were censored at time of post-transplant fundoplication,last clinic visit,or death,whichever was earliest.RESULTS Seventy subjects(58%men,mean age:56 years)met the inclusion criteria.Interstitial lung disease represented the predominant pulmonary diagnosis(40%).Baseline demographics were similar between groups and were not associated with pulmonary decline.The clinical endpoint(≥20%FEV1 decline)was reached in 18 subjects(26%).In time-to-event univariate analysis,FEV1 decline was associated with increased acid exposure time(AET)[hazard ratio(HR)=3.49,P=0.03]and increased proximal acid reflux(HR=3.34,P=0.04)with confirmation on Kaplan-Meier analysis.Multivariate analysis showed persistent association between pulmonary decline and increased AET(HR=3.37,P=0.04)when controlling for potential confounders including age,body mass index,and sex.Subgroup analysis including only patients with FEV1 decline showed that all subjects with abnormal AET progressed to bronchiolitis obliterans syndrome.CONCLUSION Increased reflux burden on pre-transplant testing was associated with significant pulmonary function decline posttransplant.Pre-transplant reflux assessment may provide clinically relevant information in the prognostication and management of transplant recipients.展开更多
Quinoid structures are considered to be conducive to the charge transport of organic molecules,but this hypothesis is rarely proven at single-molecule level.Herein,as a proof of concept,the single-molecule conductance...Quinoid structures are considered to be conducive to the charge transport of organic molecules,but this hypothesis is rarely proven at single-molecule level.Herein,as a proof of concept,the single-molecule conductance of two furan-based isomers,3,3'-bis(4-(methylthio)phenyl)-2,2'-bifuran(2,2'-SMPBF)and 4,4'-bis(4-(methylthio)phenyl)-3,3'-bifuran(3,3'-SMPBF),is investigated by the scanning tunneling microscopy break junction(STM-BJ)technique and theoretical simulation.2,2'-SMPBF prefers to adopt a nearly planar conformation with intact alternating single and double bonds extended via2,2'-bifuran moiety and therefore exhibits goodπ-conjugation and a prominent quinoid structure.However,theπ-conjugation of 3,3'-SMPBF is interrupted due to ineffective cross-conjugation in the 3,3'-bifuran moiety,leading to the absence of a quinoid structure.2,2'-SMPBF displays switchable multiple conductances induced by the interconversion between folded and unfolded conformations and an abnormal rebound of conductance along with the increases of electrode displacement,which is demonstrated to be caused by the quinoid structure in a nearly planar conformation during the stretching process.However,3,3'-SMPBF without a quinoid structure in unfolded conformation exhibits extremely low conductance that cannot be captured in STM-BJ measurements.These results reveal the significant contribution of quinoid structure to molecular charge transport and provide valuable information on the structure-transport relationship for the design of efficient organic semiconductors.展开更多
基金Supported by the National Natural Science Foundation of China(61231015,61401319)the Natural Science Foundation of Hubei Province(2015CFA061)
文摘The 22.2 multichannel system and its simplified system with 10-channel and 8-channel have been proposed, which brings people 3 D listening experience. But these systems could only accurately reproduce sound field at a central listening point which is called sweetspot. In order to solve this problem, this paper proposes a non-central zone sound field reproduction method PVMDZ（particle velocity matching between different zones） based on the physical property of sound. The proposed method matches the physical property of sound of non-central zone in reconstructed sound field with that of central zone in original sound field, so the reproduced non-central zone would produce the same listening experience as the central zone of the original system does. By experiments, we compare the performances of the proposed method with the traditional one, and the result proves that the sound field error of proposed method is reduced.
文摘The two-phase flow instabilities observed in through parallel multichannel can be classified into three types,of which only one is intrinsic to parallel multichannel systems.The intrinsic instabilities observed in parallel multichannel system have been studied experimentally.The stable boundary of the flow in such a parallel-channel system are sought,and the nature of inlet flow oscillation in the unstable region has been examined experimentally under various conditions of inlet velocity,heat flux,liquid temperature,cross section of channel and entrance throttling.The results show that parallel multichannel system possess a characteristic oscillation that is quite independent of the magnitude and duration of the initial disturbance,and the stable boundary is influenced by the characteristic frequency of the system as well as by the exit quality when this is low,and upon raising the exit quality and reducing the characteristic frequency,the system increases its instability,and entrance throttling effectively contributes to stabilization of the system.
基金supported by the special funds of Laoshan Laboratory(No.LSKJ202203604)the National Key Research and Development Program of China(No.2016 YFC0303901).
文摘The near-seabed multichannel seismic exploration systems have yielded remarkable successes in marine geological disaster assessment,marine gas hydrate investigation,and deep-sea mineral exploration owing to their high vertical and horizontal resolution.However,the quality of deep-towed seismic imaging hinges on accurate source-receiver positioning information.In light of existing technical problems,we propose a novel array geometry inversion method tailored for high-resolution deep-towed multichannel seismic exploration systems.This method is independent of the attitude and depth sensors along a deep-towed seismic streamer,accounting for variations in seawater velocity and seabed slope angle.Our approach decomposes the towed line array into multiline segments and characterizes its geometric shape using the line segment distance and pitch angle.Introducing optimization parameters for seawater velocity and seabed slope angle,we establish an objective function based on the model,yielding results that align with objective reality.Employing the particle swarm optimization algorithm enables synchronous acquisition of optimized inversion results for array geometry and seawater velocity.Experimental validation using theoretical models and practical data verifies that our approach effectively enhances source and receiver positioning inversion accuracy.The algorithm exhibits robust stability and reliability,addressing uncertainties in seismic traveltime picking and complex seabed topography conditions.
基金supported in part by the National Natural Science Foundation of China under Grant 42174164 and Grant 41704132in part by the Key Program of the Joint Fund of the Science,Technology,and Education of Sichuan Province,China under Grant 2024NSFSC1955+4 种基金in part by the Natural Science Foundation of Sichuan Province,China under Grant 2024NSFSC0080in part by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Independent Research Project under Grant SKLGP2022Z011in part by the Chengdu University of Technology Postgraduate Innovative Cultivation Program:Spatiotemporal Characterization of Seismic Signals for Tight Channel Sandstone Gas Reservoirs in the Synchro-Squeezing/Extracting Transform Domain under Grant CDUT2023BJCx002in part by the Creative Research Groups of the Natural Science Foundation of Sichuan under Grant 2023NSFSC198414th Five Year Plan Major Science and Technology Project of CNOOC under Grant KJGG2022-0903.
文摘As seismic signals propagate underground,the subsurface media absorb high-frequency components,decreasing seismic resolution and limiting the identification and characterization of thin reservoirs.To address the limitation,this paper proposes a multichannel spectral fitting(MSF)method.The MSF method aims to enhance seismic resolution by considering the spectral characteristics and the correlations between adjacent seismic traces.The key to the MSF method involves utilizing the amplitude spectrum of the attenuated Ricker wavelet to construct an objective function for spectral fitting,leading to improved seismic resolution.Furthermore,the MSF method establishes the correlation between adjacent seismic traces as a constraint to stably solve the target parameters based on the entire seismic spectrum,which helps obtain horizontally consistent and more realistic seismic signals.Synthetic and field seismic examples demonstrate that the proposed method not only provides higher-resolution seismic signals but also reveals more fine details of thin reservoirs compared to the time-variant spectral whitening method.It is concluded that the MSF method is a promising tool for seismic signal processing.
基金supported by the basic and forward-looking project(No.2023YQX302)。
文摘Traditional deconvolution methods based on single-channel inversion do not consider the spatial structural relation between channels,and hence,they yield high-resolution results with the existing transverse inconsistency or discontinuity.Therefore,in this study,the local dip angle was used to obtain the structural information and construct the spatial structurally constraint operator.This operator is then introduced into multichannel deconvolution as a regularization operator to improve the resolution and maintain the transverse continuity of seismic data.Model tests and actual seismic data processing have demonstrated the effectiveness and practicability of this method.
文摘Normally, Data acquisition (DAQ) is used to acquire the signals from different devices like sensors, transducers, actuators etc. The data acquisition is also used to analyze the signals, digitizing the signals and acquiring the signals from different inputs. The main drawbacks in data acquisition system are data storage, hardware size and remote monitoring. The System-on-Chip Field Programmable Gate Array (SoC-FPGA) is used in the proposed system in the aim to reduce the hardware and memory size. Further to provide remote monitoring with Ethernet/Wi-Fi, the Network Control Module (NCM) is integrated with Data acquisition and processing module for the communication between the systems. This developed system achieves high resolution with memory reduction, reduced hardware size, fast remote monitoring and control. It is used for real time processing in DAQ and signal processing. For fault tolerance and portability, the full system reconfigurability based FPGA acts as the best solution and the system can be reused with different configurations. The control of data acquisition and the subsequent management of data are coded in LabVIEW. LabVIEW tool is used to design and develop a four-channel Data Acquisition and Processing (DAQP) unit. National Instruments Data Acquisition (NIDAQ) and National Instruments Field Programmable Gate Array (NIFPGA) are used to test and implement the design for real time processing. This is designed to provide high accuracy, storage and portability.
基金financially supported by a National Research Foundation of Korea(NRF)from the Korean government(MSIT)(No.2020R1C1C1003375)。
文摘Potassium-ion batteries(PIBs)have gained significant attention as an alternative to lithium-ion batteries(LIBs)due to the abundance of potassium(K)and low cost.Nevertheless,the difficulty in finding appropriate electrode materials that can efficiently store the larger K ions has hindered their practical application.Herein,we report a novel anode material,N-doped multichannel carbon nanofibers embedded with porous CoS nanoprisms(CSP@NMCNF),for high-performance PIBs.The CSP@NMCNF was synthesized using a two-step strategy comprising of the electrospinning of Co acetate hydroxide nanoprism/binary polymer blend and a subsequent heat treatment.The porous CoS nanoprisms with an anisotropic morphology were well aligned along the length axis of the N-doped multichannel carbon nanofibers,thus ensuring their structural stability during the repeated charge-discharge process.In addition,numerous pores facilitated the transport of electrons and ions.Accordingly,the CSP@NMCNF anode exhibited excellent electrochemical performance,delivering a high specific capacity of 368 mAh·g^(-1)at 0.5 A·g^(-1)after 200 cycles and excellent rate capability(232 mAh·g^(-1)at 2.0 A·g^(-1)).
基金Key-Area Research and Development Program of Guangdong Province(2019B090915002).
文摘Background A large number of robots have put forward the new requirements for human robot interaction.One of the problems in human-swarm robot interaction is how to naturally achieve an efficient and accurate interaction between humans and swarm robot systems.To address this,this paper proposes a new type of human-swarm natural interaction system.Methods Through the cooperation between three-dimensional(3D)gesture interaction channel and natural language instruction channel,a natural and efficient interaction between a human and swarm robots is achieved.Results First,A 3D lasso technology realizes a batch-picking interaction of swarm robots through oriented bounding boxes.Second,control instruction labels for swarm-oriented robots are defined.The instruction label is integrated with the 3D gesture and natural language through instruction label filling.Finally,the understanding of natural language instructions is realized through a text classifier based on the maximum entropy model.A head-mounted augmented reality display device is used as a visual feedback channel.Conclusions The experiments on selecting robots verify the feasibility and availability of the system.
文摘The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFC3000103)the National Natural Science Foundation of China(Grant No.41504081)。
文摘With the constantly changing engineering construction sector,the detection accuracy of conventional electrical resistivity tomography(ERT)is no longer sufficient.A multichannel electrode design(MERT)-based ERT is introduced in this paper to address the growing need for resolution.The imaging accuracy of the ERT method is improved through the collection of apparent resistivity data in various directions by measuring the potential diff erence between diff erent channels.Numerical simulation results of the inclined high-resistivity anomaly model reveal that MERT is a precise representation of the shape,inclined direction,and buried depth of the anomaly,with thoroughfare M2N2 producing the most precise forward and inverse results.Based on the analysis results of the model resolution matrix,when the buried depth of power supply points and the gap between potential acquisition points are 30%-90%and 30%-60%of the electrode distance,respectively,the MERT approach yields superior detection outcomes.The detection eff ect of the MERT method on anomalous bodies with diff erent burial depths under the optimal parameters also indicates that the MERT method can obtain richer potential change information with higher resolution in deep areas compared to the ERT method.With the implementation of the MERT approach,the scope of applications for ERT is expanded,the accuracy of ERT detection is increased,and the progress of near-surface fine detection is positively infl uenced.
基金financially supported by Tianjin Municipal Education Commission Scientific Research Project(No.2018KJ151)the National Natural Science Foundation of China(No.51773094)Tianjin Research Innovation Project for Postgraduate Students(No.2021YJSB245)。
文摘The balancing of the electrochemical performance,mechanical stability,and processing technology for applying supercapacitors to flexible and wearable electronics continues to encounter severe challenges.Herein,we prepare Ni-Co-Mn hydroxide electrodes with a threedimensional multichannel structure via a simple hydrothermal method.These are constructed using vertically contiguous nano sheets with a uniform thickness and rough surface.The electrodes can provide numerous electroactive sites and accelerate the transmission of electrolyte ions.The relationship between the structure and electrochemical performances is verified by experiments and theoretical calculations.Two-dimensional(2D)planar and one-dimensional(1D)fiber electrodes are prepared using a flexible carbon cloth(CC)and carbon fiber(CF),respectively,as substrates.The assembled quasi-solid-state flexible asymmetric supercapacitor(FASC)with a twodimensional sandwich structure using NiCoMn-OH/CC as the electrode achieves a remarkable energy density of73.8 Wh·kg^(-1)at a power density of 1.03 kW·kg^(-1).The quasi-solid-state FASC with a 1D linear structure using NiCoMn-OH/CF as the electrode also attains a high energy density(12.9 Wh·kg^(-1)at a power density of0.75 W·kg^(-1)).Moreover,the electrochemical performances of the NiCoMn/CC//AC/CC and NiCoMn/CF//AC/CF FASCs are not disturbed at different bending angles(0°,45°,90°,135°and 180°),This indicates the superior flexibility of the devices.We also assemble a self-powered energy-harvesting storage system by integrating FASCs and commercial solar cells to verify its practicability.It displays sustainable development potential for energy storage.
基金supported by the National Natural Science Foundation(NSFC)of China(22179094)the research funding provided by Cangzhou Institute of Tiangong University(Grant No.TGCYY-Z-0202)
文摘Zn metal anodes are usually subject to grave dendrite growth during platting/stripping,which dramatically curtails the lifespan of aqueous Zn-ion batteries and capacitors.To address above problems,in our work,a novel phosphorus-functionalized multichannel carbon interlayer was designed and covered on Zn anodes.The results demonstrated that the multichannel structure combined with the three-dimensional meshy skeleton can provide more sufficient space for Zn deposition,thereby effectively inhibiting the growth of zinc dendrites.Meanwhile,theoretical calculations also confirmed that the P-C and P=O functional groups from phosphorus-functionalized multichannel carbon interlayer have the decisive influence in reducing the zinc nucleation potential and depositing uniformly zinc.Concretely,the symmetrical battery assembled with phosphorus-functionalized multichannel carbon interlayer-covered Zn anodes possessed a long lifetime of 3300 h at 2 mA cm^(-2)with 1 mAh cm^(-2).Furthermore,the full cell with activated carbon cathodes exhibited a high specific capacity of 80.5 mAh g^(-1)and outstanding cycling stability without capacity decay after 15000 cycles at a high current density of 5 A g^(-1).The superior electrochemical performance exceeded that of most reported papers.Consequently,our synthesized zincophilic interlayer with the unique structure has superior prospects for application in stabilizing zinc anodes and prolonging the lifespan of batteries.
基金supported in part by the National Natural Science Foundation of China under Grant No.62375103 and Grant No.62131018in part by the National Key Research and Development Program of China under Grant No.2021YFF0502700Innovation Program for Quantum Science and Technology(Grant No.2021ZD0300701).
文摘Distributed fiber gratings exhibit outstanding capabilities in achieving a wide spectral response through the superimposition of gratings with different periods in the fiber core.This significantly broadens the design flexibility and potential applications of fiber gratings.However,as photons pass through gratings with varying periods in sequence,which not only inevitably existing signal crosstalk but also poses challenges for integrating.In this study,a three-dimensional(3D)four-channel filter is proposed and realized in fiber-compatible materials using femtosecond laser writing.The filter consists of a 3D beam splitter and four parallel different-period Bragg waveguide gratings(WGs).By designing grating periods in each path,parallel filtering and reflection at multiple designed wavelengths are achieved compactly with 50 nm spectrum spacing within 1450-1600 nm wavelengths.The four-channel filter entire measures 15.5 mm×1 mm×1 mm(the highest integration of distributed fiber gratings reported so far).Our technique will augment the laser fabrication technology for 3D integrated photonic devices and serve as a powerful and generalized solution for highly integrated in-situ measurement and multi-parameter decoupled sensing.
文摘涡桨飞机座舱的主动噪声控制系统普遍采用传统的多通道滤波x最小均方(multichannel filtered-x least mean square,简称McFxLMS)算法,该算法的计算量随着通道数的增加而激增,严重影响控制效果。针对该问题,基于连续局部迭代-McFxLMS(sequential partial update-McFxLMS,简称SPU-McFxLMS)算法,开发了多通道主动噪声控制系统。SPU-McFxLMS算法通过更新部分滤波器权值,在保证收敛精度的同时能够显著降低计算复杂度。首先,对比分析了传统McFxLMS算法与SPU-McFxLMS算法的原理差异,通过理论推导证明其计算效率提升特性;其次,建立了算法仿真模型,通过仿真验证了理论分析结果;最后,基于SOM-TL6678核心板开发了16通道的主动噪声控制系统,并搭建飞机座舱地面模拟实验平台进行实验。结果表明,该系统在108 Hz和216 Hz双频噪声场景下,各位置的平均降噪量能够达到10 dB以上。
文摘复杂环境如汽车车厢内路噪的有源噪声控制(Active Noise Control,ANC)通常依赖大量传感器来获得有效的噪声控制性能,使应用传统自适应算法的收敛速度缓慢且计算量较大.针对这一问题,在频域滤波参考最小均方(Frequency Domain Filtered-x Least Mean Square,FDFxLMS)算法的基础上提出了多迭代预处理正则化频域滤波参考最小均方(Multi-Iterative Pre-Regularized Frequency Domain Filtered-x Least Mean Square,MIPR-FDFxLMS)算法,该算法的多迭代策略提升了算法收敛速度并保持较高的计算效率,预处理的正则化因子改进方法保证了算法的稳定收敛.基于实测汽车道路噪声数据的仿真结果表明,与传统自适应算法相比,提出的MIPR-FDFxLMS算法在收敛速度方面具有明显优势,展示了其在实际路噪控制系统中的应用前景.
基金The National Natural Science Foundation of China(No.30900356,81071135)the National High Technology Research and Development Program of China(863Program)(No.2008AA02Z410)
文摘A multichannel matching pursuit（MMP）algorithm is proposed to decompose the one-dimensional multichannel non-stationary magnetoencephalography（MEG）signal at a single-trial level.The single-channel matching pursuit（MP）linearly decomposes the signal into a set of Gabor atoms,which are adaptively chosen from an overcomplete dictionary with good time-frequency characters.The MMP is the extension of the MP,which represents multichannel signals using linear combination of Gabor atoms with the same occurrence,frequency,phase,and time width,but varying amplitude in all channels.The results demonstrate that the MMP can optimally reconstruct the original signal and automatically remove artifact noises.Moreover,the coherence between the 3D source reconstruction and the prior knowledge of psychology further suggests that the MMP is effective in MEG single-trial processing.
文摘Recently,Luolai Group released its Q12025 quarterly report.As a leading Chinese home textile enterprise listed on the Shenzhen Stock Exchange in 2009,the company covers the research,design,production,and sales of home textile products,and has multiple brands covering different consumer markets.It has expanded its online and offline comprehensive multichannel sales system and is committed to creating a win-win home furnishings and textile industry ecosystem.
文摘BACKGROUND Gastroesophageal reflux disease has been shown to contribute to allograft injury and rejection outcomes in lung transplantation through a proposed mechanism of aspiration,inflammation,and allograft injury.The value of pre-transplant reflux testing in predicting reduction in pulmonary function after lung transplantation is unclear.We hypothesized that increased reflux burden on pre-transplant reflux testing is associated with pulmonary function decline following lung transplant.AIM To assess the relationship between pre-transplant measures of reflux and pulmonary function decline in lung transplant recipients.METHODS This was a retrospective cohort study of lung transplant recipients who underwent pre-transplant reflux testing with 24-hour pH-impedance off acid suppression at a tertiary center in 2007-2016.Patients with pre-transplant fundoplication were excluded.Time-to-event analysis was performed using Cox proportional hazards models to assess associations between reflux measures and reduction in forced expiratory volume in 1 second(FEV1)of≥20%post-transplant.Patients not meeting endpoint were censored at time of post-transplant fundoplication,last clinic visit,or death,whichever was earliest.RESULTS Seventy subjects(58%men,mean age:56 years)met the inclusion criteria.Interstitial lung disease represented the predominant pulmonary diagnosis(40%).Baseline demographics were similar between groups and were not associated with pulmonary decline.The clinical endpoint(≥20%FEV1 decline)was reached in 18 subjects(26%).In time-to-event univariate analysis,FEV1 decline was associated with increased acid exposure time(AET)[hazard ratio(HR)=3.49,P=0.03]and increased proximal acid reflux(HR=3.34,P=0.04)with confirmation on Kaplan-Meier analysis.Multivariate analysis showed persistent association between pulmonary decline and increased AET(HR=3.37,P=0.04)when controlling for potential confounders including age,body mass index,and sex.Subgroup analysis including only patients with FEV1 decline showed that all subjects with abnormal AET progressed to bronchiolitis obliterans syndrome.CONCLUSION Increased reflux burden on pre-transplant testing was associated with significant pulmonary function decline posttransplant.Pre-transplant reflux assessment may provide clinically relevant information in the prognostication and management of transplant recipients.
基金financially supported by the National Natural Science Foundation of China(Nos.U23A20594,22375066 and 21788102)Guang Dong Basic and Applied Basic Research Foundation(No.2023B1515040003)。
文摘Quinoid structures are considered to be conducive to the charge transport of organic molecules,but this hypothesis is rarely proven at single-molecule level.Herein,as a proof of concept,the single-molecule conductance of two furan-based isomers,3,3'-bis(4-(methylthio)phenyl)-2,2'-bifuran(2,2'-SMPBF)and 4,4'-bis(4-(methylthio)phenyl)-3,3'-bifuran(3,3'-SMPBF),is investigated by the scanning tunneling microscopy break junction(STM-BJ)technique and theoretical simulation.2,2'-SMPBF prefers to adopt a nearly planar conformation with intact alternating single and double bonds extended via2,2'-bifuran moiety and therefore exhibits goodπ-conjugation and a prominent quinoid structure.However,theπ-conjugation of 3,3'-SMPBF is interrupted due to ineffective cross-conjugation in the 3,3'-bifuran moiety,leading to the absence of a quinoid structure.2,2'-SMPBF displays switchable multiple conductances induced by the interconversion between folded and unfolded conformations and an abnormal rebound of conductance along with the increases of electrode displacement,which is demonstrated to be caused by the quinoid structure in a nearly planar conformation during the stretching process.However,3,3'-SMPBF without a quinoid structure in unfolded conformation exhibits extremely low conductance that cannot be captured in STM-BJ measurements.These results reveal the significant contribution of quinoid structure to molecular charge transport and provide valuable information on the structure-transport relationship for the design of efficient organic semiconductors.
