For the joint time difference of arrival（TDOA） and angle of arrival（AOA） location scene,two methods are proposed based on the rectangular coordinates and the polar coordinates,respectively.The problem is solved pe...For the joint time difference of arrival（TDOA） and angle of arrival（AOA） location scene,two methods are proposed based on the rectangular coordinates and the polar coordinates,respectively.The problem is solved perfectly by calculating the target position with the joint TDOA and AOA location.On the condition of rectangular coordinates,first of all,it figures out the radial range between target and reference stations,then calculates the location of the target.In the case of polar coordinates,first of all,it figures out the azimuth between target and reference stations,then figures out the radial range between target and reference stations,finally obtains the location of the target.Simultaneously,simulation analyses show that the theoretical analysis is correct,and the proposed methods also provide the application of the joint TDOA and AOA location algorithm with the theoretical basis.展开更多
The extraction of pavement cracks is always a hard task in image processing.In airport and road construction,cracking is the main factor for pavement damage,which can decrease the quality of pavement and affect transp...The extraction of pavement cracks is always a hard task in image processing.In airport and road construction,cracking is the main factor for pavement damage,which can decrease the quality of pavement and affect transportation seriously.Cracks also exist in other artificial or natural objects,such as buildings,bridges,tunnels,etc.Among all the object images,pavement crack images are the most complex,so the image processing and analysis for them is harder than other crack images.From the early image acquisition based on photography technology to the current 3 D laser scanning technology,the pavement crack image acquisition technology is becoming more convenient and efficient,but there are still challenges in the automatic processing and recognition of cracks in images.From the early global thresholding to deep learning algorithms,the research for crack extraction has been developed for about 40 years.There are many methods and algorithms that are satisfactory in pavement crack applications,but there is no standard until today.Therefore,in order to know the developing history and the advanced research,we have collected a number of literature in this research topic for summarizing the research artwork status,and giving a review of the pavement crack image acquisition methods and2 D crack extraction algorithms.Also,for image acquisition methods and pavement crack image segmentation,more detailed comparison and discussions are made.展开更多
In this paper, a new four-dimensional autonomous hyperchaotic system is designed for generating complex chaotic signals. In the design, its parameters are selected according to the requirements for chaos and hyperchao...In this paper, a new four-dimensional autonomous hyperchaotic system is designed for generating complex chaotic signals. In the design, its parameters are selected according to the requirements for chaos and hyperchaos. The hyperchaotic nature is verified theoretically by using the bifurcation analysis and demonstrated experimentally by the implementation of an analogue electronic circuit. Moreover, the Field Programmable Gate Array （FPGA） technology is applied to implementing a continuous system in a digital form by using a chip of Altera Cyclone II EP2C35F484C8. The digital sequence generated from the FPGA device is observed in our experimental setup.展开更多
Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since ...Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.展开更多
As the fifth-generation(5G)mobile communication network may not meet the requirements of emerging technologies and applications,including ubiquitous coverage,industrial internet of things(IIoT),ubiquitous artificial i...As the fifth-generation(5G)mobile communication network may not meet the requirements of emerging technologies and applications,including ubiquitous coverage,industrial internet of things(IIoT),ubiquitous artificial intelligence(AI),digital twins(DT),etc.,this paper aims to explore a novel space-air-ground integrated network(SAGIN)architecture to support these new requirements for the sixth-generation(6G)mobile communication network in a flexible,low-latency and efficient manner.Specifically,we first review the evolution of the mobile communication network,followed by the application and technology requirements of 6G.Then the current 5G non-terrestrial network(NTN)architecture in supporting the new requirements is deeply analyzed.After that,we proposes a new flexible,low-latency and flat SAGIN architecture,and presents corresponding use cases.Finally,the future research directions are discussed.展开更多
Quantum secure direct communication(QSDC)is a unique technique,which supports the secure transmission of confidential information directly through a quantum channel without the need for a secret key and for ciphertext...Quantum secure direct communication(QSDC)is a unique technique,which supports the secure transmission of confidential information directly through a quantum channel without the need for a secret key and for ciphertext.Hence this secure communication protocol fundamentally differs from its conventional counterparts.In this article,we report the first measurement-deviceindependent(MDI)QSDC protocol relying on sequences of entangled photon pairs and single photons.Explicitly,it eliminates the security loopholes associated with the measurement device.Additionally,this MDI technique is capable of doubling the communication distance of its conventional counterpart operating without using our MDI technique.We also conceive a protocol associated with linear optical Bell-basis measurements,where only two of the four Bell-basis states could be measured.When the number of qubits in a sequence reduces to 1,the MDI-QSDC protocol degenerates to a deterministic MDI quantum key distribution protocol.展开更多
The quantum dot spectrometer,fabricated by integrating different quantum dots with an image sensor to reconstruct the target spectrum from spectral-coupled measurements,is an emerging and promising hyperspectrometry t...The quantum dot spectrometer,fabricated by integrating different quantum dots with an image sensor to reconstruct the target spectrum from spectral-coupled measurements,is an emerging and promising hyperspectrometry technology with high resolution and a compact size.The spectral resolution and spectral range of quantum dot spectrometers have been limited by the spectral variety of the available quantum dots and the robustness of algorithmic reconstruction.Moreover,the spectrometer integration of quantum dots also suffers from inherent photoluminescence emission and poor batch-to-batch repeatability.In this work,we developed nonemissive in situ fabricated MA_(3)Bi_(2)X_(9) and Cs_(2)SnX_(6)(MA=CH_(3)NH_(3);X=Cl,Br,I)perovskite-quantum-dot-embedded films(PQDFs)with precisely tunable transmittance spectra for quantum dot spectrometer applications.The resulting PQDFs contain in situ fabricated perovskite nanocrystals with homogenous dispersion in a polymeric matrix,giving them advantageous features such as high transmittance efficiency and good batch-to-batch repeatability.By integrating a filter array of 361 kinds of PQDFs with a silicon-based photodetector array,we successfully demonstrated the construction of a perovskite quantum dot spectrometer combined with a compressive-sensing-based total-variation optimization algorithm.A spectral resolution of ~1.6 nm was achieved in the broadband of 250-1000 nm.The performance of the perovskite quantum dot spectrometer is well beyond that of human eyes in terms of both the spectral range and spectral resolution.This advancement will not only pave the way for using quantum dot spectrometers for practical applications but also significantly impact the development of artificial intelligence products,clinical treatment equipment,scientific instruments,etc.展开更多
Electronic skin is driving the next generation of cutting-edge wearable electronic products due to its good wearability and high accuracy of information acquisition.However,it remains a challenge to fulfill the requir...Electronic skin is driving the next generation of cutting-edge wearable electronic products due to its good wearability and high accuracy of information acquisition.However,it remains a challenge to fulfill the requirements on detecting full-range human activities with existing flexible strain sensors.Herein,highly stretchable,sensitive,and multifunctional flexible strain sensors based on MXene-(Ti_(3)C_(2)T_(x)-)composited poly(vinyl alcohol)/polyvinyl pyrrolidone double-network hydrogels were prepared.The uniformly distributed hydrophilic MXene nanosheets formed a three-dimensional conductive network throughout the hydrogel,endowing the flexible sensor with high sensitivity.The strong interaction between the double-network hydrogel matrix and MXene greatly improved the mechanical properties of the hydrogels.The resulting nanocomposited hydrogels featured great tensile performance(2400%),toughness,and resilience.Particularly,the as-prepared flexible pressure sensor revealed ultrahigh sensitivity(10.75 kPa^(-1))with a wide response range(0-61.5 kPa),fast response(33.5 ms),and low limit of detection(0.87 Pa).Moreover,the hydrogel-based flexible sensors,with high sensitivity and durability,could be employed to monitor fullrange human motions and assembled into some aligned devices for subtle pressure detection,providing enormous potential in facial expression and phonation recognition,handwriting verification,healthy diagnosis,and wearable electronics.展开更多
DURING our discussion at workshops for writing“What Does ChatGPT Say:The DAO from Algorithmic Intelligence to Linguistic Intelligence”[1],we had expected the next milestone for Artificial Intelligence(AI)would be in...DURING our discussion at workshops for writing“What Does ChatGPT Say:The DAO from Algorithmic Intelligence to Linguistic Intelligence”[1],we had expected the next milestone for Artificial Intelligence(AI)would be in the direction of Imaginative Intelligence(II),i.e.,something similar to automatic wordsto-videos generation or intelligent digital movies/theater technology that could be used for conducting new“Artificiofactual Experiments”[2]to replace conventional“Counterfactual Experiments”in scientific research and technical development for both natural and social studies[2]-[6].Now we have OpenAI’s Sora,so soon,but this is not the final,actually far away,and it is just the beginning.展开更多
Dempster-Shafer (DS) theory of evidence has been widely used in many data fusion ap- plication systems. However, how to determine basic probability assignment, which is the main and the first step in evidence theory, ...Dempster-Shafer (DS) theory of evidence has been widely used in many data fusion ap- plication systems. However, how to determine basic probability assignment, which is the main and the first step in evidence theory, is still an open issue. In this paper, a new method to obtain Basic Probability Assignment (BPA) is proposed based on the similarity measure between generalized fuzzy numbers. In the proposed method, species model can be constructed by determination of the min, average and max value to construct a fuzzy number. Then, a new Radius Of Gravity (ROG) method to determine the similarity measure between generalized fuzzy numbers is used to calculate the BPA functions of each instance. Finally, the efficiency of the proposed method is illustrated by the classi- fication of Iris data.展开更多
Metal oxide semiconductor heterojunctions(MOSHs)can enhance the performance of ethanol gas sen-sors substantially.Ethanol gas sensors based on MOSHs are cost-effective and have excellent sensing response,good selectiv...Metal oxide semiconductor heterojunctions(MOSHs)can enhance the performance of ethanol gas sen-sors substantially.Ethanol gas sensors based on MOSHs are cost-effective and have excellent sensing response,good selectivity,fast response and recovery,long-term stability or repeatability,a low operating temperature,a facile fabrica-tion process,and versatile applications.This paper reviews the recent advances in gas sensors that are based on MOSHs and the advantages of using them to detect ethanol gas.According to the literature,compared with ethanol gas sen-sors that use single-component sensing materials,the MOSHs exhibit superior performance due to the synergy between the different components,which can amplify the reception and transduction components of the sensor signals.To the best of our knowledge,heterojunctions can be grouped into four main categories as metal oxide/metal oxide,metal oxide/metal sulfide,metal oxide/noble metal,and metal oxide/other materials,including rare-earth metals,g-C_(3)N_(4),and graphene,heterojunctions.The future trends and challenges that would be faced in the development of ethanol gas sensors based on MOSHs are discussed in detail.Finally,critical ideas and thinking regarding the future progress of MOSH-based gas sensors are presented.展开更多
While moving ahead with the object detection technology, especially deep neural networks, many related tasks, such as medical application and industrial automation, have achieved great success. However, the detection ...While moving ahead with the object detection technology, especially deep neural networks, many related tasks, such as medical application and industrial automation, have achieved great success. However, the detection of objects with multiple aspect ratios and scales is still a key problem. This paper proposes a top-down and bottom-up feature pyramid network(TDBU-FPN),which combines multi-scale feature representation and anchor generation at multiple aspect ratios. First, in order to build the multi-scale feature map, this paper puts a number of fully convolutional layers after the backbone. Second, to link neighboring feature maps, top-down and bottom-up flows are adopted to introduce context information via top-down flow and supplement suboriginal information via bottom-up flow. The top-down flow refers to the deconvolution procedure, and the bottom-up flow refers to the pooling procedure. Third, the problem of adapting different object aspect ratios is tackled via many anchor shapes with different aspect ratios on each multi-scale feature map. The proposed method is evaluated on the pattern analysis, statistical modeling and computational learning visual object classes(PASCAL VOC)dataset and reaches an accuracy of 79%, which exhibits a 1.8% improvement with a detection speed of 23 fps.展开更多
The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to t...The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to the fascinating advantages such as high speed,wide bandwidth,and massive parallelism.Here,we offer a review on the optical neural computing in our research groups at the device and system levels.The photonics neuron and photonics synapse plasticity are presented.In addition,we introduce several optical neural computing architectures and algorithms including photonic spiking neural network,photonic convolutional neural network,photonic matrix computation,photonic reservoir computing,and photonic reinforcement learning.Finally,we summarize the major challenges faced by photonic neuromorphic computing,and propose promising solutions and perspectives.展开更多
Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allo...Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.展开更多
Active energy management is an effective way to realize the flexible utilization of distributed energy resources to suit the characteristics of active distribution system.Advanced active energy management strategies n...Active energy management is an effective way to realize the flexible utilization of distributed energy resources to suit the characteristics of active distribution system.Advanced active energy management strategies need to be designed to coordinate the optimization of‘generation,network,load’.An active management model is built for the local distribution system integrated with the generation curtailment mechanism and the charging/discharging management of plug-in electric vehicles.Furthermore,different strategies based on the energy management model are presented.The model and strategies are tested and discussed in a modified distribution system,and the impacts with different load profiles are also analyzed.展开更多
This paper presents a method for detecting the small infrared target under complex background. An algorithm, named local mutation weighted information entropy （LMWIE）, is proposed to suppress background. Then, the g...This paper presents a method for detecting the small infrared target under complex background. An algorithm, named local mutation weighted information entropy （LMWIE）, is proposed to suppress background. Then, the grey value of targets is enhanced by calculating the local energy. Image segmentation based on the adaptive threshold is used to solve the problems that the grey value of noise is enhanced with the grey value improvement of targets. Experimental results show that compared with the adaptive Butterworth high-pass filter method, the proposed algorithm is more effective and faster for the infrared small target detection.展开更多
Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality control.Conventional infrared imaging technologies,howeve...Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality control.Conventional infrared imaging technologies,however,require the use of materials such as narrow bandgap semiconductors,which are sensitive to thermal noise and often require cryogenic cooling.We demonstrate a compact all-optical alternative to perform infrared imaging in a metasurface composed of GaAs semiconductor nanoantennas,using a nonlinear wave-mixing process.We experimentally show the upconversion of short-wave infrared wavelengths via the coherent parametric process of sum-frequency generation.In this process,an infrared image of a target is mixed inside the metasurface with a strong pump beam,translating the image from the infrared to the visible in a nanoscale ultrathin imaging device.Our results open up new opportunities for the development of compact infrared imaging devices with applications in infrared vision and life sciences.展开更多
Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide(MoS_(2));however,most of them were confined to the level below the damage threshold.Here the electro...Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide(MoS_(2));however,most of them were confined to the level below the damage threshold.Here the electron dynamics of MoS_(2) under intense ultrafast laser irradiation was investigated by experiments and simulations.Two kinds of ablation mechanisms were revealed,which led to two distinct types of electron dynamics and final ablation morphology.At a higher fluence,the emergence of superheated liquid induced a dramatic change in the transient reflectivity and micro-honeycomb structures.At a lower fluence,the material was just removed by sublimation,and the ablation structure was relatively flat.X-ray photoelectron spectroscopic(XPS)measurements demonstrated that thermal decomposition only occurred at the higher fluence.Furthermore,a theoretical model was developed to deeply reveal the ultrafast dynamics of MoS_(2) ablation.The simulation results were in good agreement with the temporal and spatial reflectivity distribution obtained from the experiment.The electron and lattice temperature evolution was also obtained to prove the ablation mechanism.Our results revealed ultrafast dynamics of MoS_(2) above the damage threshold and are helpful for understanding the interaction mechanism between MoS_(2) and intense ultrafast lasers,as well as for MoS_(2) processing applications.展开更多
High-throughput computational imaging requires efficient processing algorithms to retrieve multi-dimensional and multi-scale information.In computational phase imaging,phase retrieval(PR)is required to reconstruct bot...High-throughput computational imaging requires efficient processing algorithms to retrieve multi-dimensional and multi-scale information.In computational phase imaging,phase retrieval(PR)is required to reconstruct both amplitude and phase in complex space from intensity-only measurements.The existing PR algorithms suffer from the tradeoff among low computational complexity,robustness to measurement noise and strong generalization on different modalities.In this work,we report an efficient large-scale phase retrieval technique termed as LPR.It extends the plug-and-play generalized-alternating-projection framework from real space to nonlinear complex space.The alternating projection solver and enhancing neural network are respectively derived to tackle the measurement formation and statistical prior regularization.This framework compensates the shortcomings of each operator,so as to realize high-fidelity phase retrieval with low computational complexity and strong generalization.We applied the technique for a series of computational phase imaging modalities including coherent diffraction imaging,coded diffraction pattern imaging,and Fourier ptychographic microscopy.Extensive simulations and experiments validate that the technique outperforms the existing PR algorithms with as much as 17dB enhancement on signal-to-noise ratio,and more than one order-of-magnitude increased running efficiency.Besides,we for the first time demonstrate ultralarge-scale phase retrieval at the 8K level(7680×4320 pixels)in minute-level time.展开更多
基金supported by the National Natural Science Foundation of China(6107210761271300)+4 种基金the Shaanxi Industry Surmount Foundation(2012K06-12)the Arm and Equipment Pre-research Foundationthe Fundamental Research Funds for the Central Universities of China(K0551302006K5051202045K50511020024)
文摘For the joint time difference of arrival（TDOA） and angle of arrival（AOA） location scene,two methods are proposed based on the rectangular coordinates and the polar coordinates,respectively.The problem is solved perfectly by calculating the target position with the joint TDOA and AOA location.On the condition of rectangular coordinates,first of all,it figures out the radial range between target and reference stations,then calculates the location of the target.In the case of polar coordinates,first of all,it figures out the azimuth between target and reference stations,then figures out the radial range between target and reference stations,finally obtains the location of the target.Simultaneously,simulation analyses show that the theoretical analysis is correct,and the proposed methods also provide the application of the joint TDOA and AOA location algorithm with the theoretical basis.
基金financially supported by the National Natural Science Fund in China(grant No.61170147)the National Natural Science Key Fund in China(grant No.U1401252).
文摘The extraction of pavement cracks is always a hard task in image processing.In airport and road construction,cracking is the main factor for pavement damage,which can decrease the quality of pavement and affect transportation seriously.Cracks also exist in other artificial or natural objects,such as buildings,bridges,tunnels,etc.Among all the object images,pavement crack images are the most complex,so the image processing and analysis for them is harder than other crack images.From the early image acquisition based on photography technology to the current 3 D laser scanning technology,the pavement crack image acquisition technology is becoming more convenient and efficient,but there are still challenges in the automatic processing and recognition of cracks in images.From the early global thresholding to deep learning algorithms,the research for crack extraction has been developed for about 40 years.There are many methods and algorithms that are satisfactory in pavement crack applications,but there is no standard until today.Therefore,in order to know the developing history and the advanced research,we have collected a number of literature in this research topic for summarizing the research artwork status,and giving a review of the pavement crack image acquisition methods and2 D crack extraction algorithms.Also,for image acquisition methods and pavement crack image segmentation,more detailed comparison and discussions are made.
基金Project supported by the Natural Science Foundation of Zhejiang Province, China (Grant No Y105175) the Science investigation Foundation of Hangzhou Dianzi University, China (Grant No KYS051505010)
文摘In this paper, a new four-dimensional autonomous hyperchaotic system is designed for generating complex chaotic signals. In the design, its parameters are selected according to the requirements for chaos and hyperchaos. The hyperchaotic nature is verified theoretically by using the bifurcation analysis and demonstrated experimentally by the implementation of an analogue electronic circuit. Moreover, the Field Programmable Gate Array （FPGA） technology is applied to implementing a continuous system in a digital form by using a chip of Altera Cyclone II EP2C35F484C8. The digital sequence generated from the FPGA device is observed in our experimental setup.
文摘Research on two-dimensional(2D) materials has been explosively increasing in last seventeen years in varying subjects including condensed matter physics, electronic engineering, materials science, and chemistry since the mechanical exfoliation of graphene in 2004. Starting from graphene, 2D materials now have become a big family with numerous members and diverse categories. The unique structural features and physicochemical properties of 2D materials make them one class of the most appealing candidates for a wide range of potential applications. In particular, we have seen some major breakthroughs made in the field of 2D materials in last five years not only in developing novel synthetic methods and exploring new structures/properties but also in identifying innovative applications and pushing forward commercialisation. In this review, we provide a critical summary on the recent progress made in the field of 2D materials with a particular focus on last five years. After a brief backgroundintroduction, we first discuss the major synthetic methods for 2D materials, including the mechanical exfoliation, liquid exfoliation, vapor phase deposition, and wet-chemical synthesis as well as phase engineering of 2D materials belonging to the field of phase engineering of nanomaterials(PEN). We then introduce the superconducting/optical/magnetic properties and chirality of 2D materials along with newly emerging magic angle 2D superlattices. Following that, the promising applications of 2D materials in electronics, optoelectronics, catalysis, energy storage, solar cells, biomedicine, sensors, environments, etc. are described sequentially. Thereafter, we present the theoretic calculations and simulations of 2D materials. Finally, after concluding the current progress, we provide some personal discussions on the existing challenges and future outlooks in this rapidly developing field.
基金supported in part by the National Key Research and Development Program under grant number 2020YFB1806800the Beijing Natural Science Foundation under grant number L212003the National Natural Science Foundation of China(NSFC)under grant numbers 62171010 and 61827901.
文摘As the fifth-generation(5G)mobile communication network may not meet the requirements of emerging technologies and applications,including ubiquitous coverage,industrial internet of things(IIoT),ubiquitous artificial intelligence(AI),digital twins(DT),etc.,this paper aims to explore a novel space-air-ground integrated network(SAGIN)architecture to support these new requirements for the sixth-generation(6G)mobile communication network in a flexible,low-latency and efficient manner.Specifically,we first review the evolution of the mobile communication network,followed by the application and technology requirements of 6G.Then the current 5G non-terrestrial network(NTN)architecture in supporting the new requirements is deeply analyzed.After that,we proposes a new flexible,low-latency and flat SAGIN architecture,and presents corresponding use cases.Finally,the future research directions are discussed.
基金supported by the National Basic Research Program of China(Grant Nos.2017YFA0303700,and 2015CB921001)the National Natural Science Foundation of China(Grant Nos.61726801,11474168,11974189,and 11474181)。
文摘Quantum secure direct communication(QSDC)is a unique technique,which supports the secure transmission of confidential information directly through a quantum channel without the need for a secret key and for ciphertext.Hence this secure communication protocol fundamentally differs from its conventional counterparts.In this article,we report the first measurement-deviceindependent(MDI)QSDC protocol relying on sequences of entangled photon pairs and single photons.Explicitly,it eliminates the security loopholes associated with the measurement device.Additionally,this MDI technique is capable of doubling the communication distance of its conventional counterpart operating without using our MDI technique.We also conceive a protocol associated with linear optical Bell-basis measurements,where only two of the four Bell-basis states could be measured.When the number of qubits in a sequence reduces to 1,the MDI-QSDC protocol degenerates to a deterministic MDI quantum key distribution protocol.
基金Supported by National Natural science Foundation-of P.R.Chlna （60474038, 60774022）, Specialized Research Fund for the Doctoral Program of Higher Educatlon（20060004002）
基金supported by the National Key R&D Program(No.2017YFB0404600)National Natural Science Foundation of China(61722502,61971045,61827901)Fundamental Research Funds for the Central Universities(3052019024).
文摘The quantum dot spectrometer,fabricated by integrating different quantum dots with an image sensor to reconstruct the target spectrum from spectral-coupled measurements,is an emerging and promising hyperspectrometry technology with high resolution and a compact size.The spectral resolution and spectral range of quantum dot spectrometers have been limited by the spectral variety of the available quantum dots and the robustness of algorithmic reconstruction.Moreover,the spectrometer integration of quantum dots also suffers from inherent photoluminescence emission and poor batch-to-batch repeatability.In this work,we developed nonemissive in situ fabricated MA_(3)Bi_(2)X_(9) and Cs_(2)SnX_(6)(MA=CH_(3)NH_(3);X=Cl,Br,I)perovskite-quantum-dot-embedded films(PQDFs)with precisely tunable transmittance spectra for quantum dot spectrometer applications.The resulting PQDFs contain in situ fabricated perovskite nanocrystals with homogenous dispersion in a polymeric matrix,giving them advantageous features such as high transmittance efficiency and good batch-to-batch repeatability.By integrating a filter array of 361 kinds of PQDFs with a silicon-based photodetector array,we successfully demonstrated the construction of a perovskite quantum dot spectrometer combined with a compressive-sensing-based total-variation optimization algorithm.A spectral resolution of ~1.6 nm was achieved in the broadband of 250-1000 nm.The performance of the perovskite quantum dot spectrometer is well beyond that of human eyes in terms of both the spectral range and spectral resolution.This advancement will not only pave the way for using quantum dot spectrometers for practical applications but also significantly impact the development of artificial intelligence products,clinical treatment equipment,scientific instruments,etc.
基金The work was supported by the National Natural Science Foundation of China(61775095)the Six Talent Peak Innovation Team in Jiangsu Province(TD-SWYY-009)‘Taishan Scholars’Construction Special Fund of Shandong Province.
文摘Electronic skin is driving the next generation of cutting-edge wearable electronic products due to its good wearability and high accuracy of information acquisition.However,it remains a challenge to fulfill the requirements on detecting full-range human activities with existing flexible strain sensors.Herein,highly stretchable,sensitive,and multifunctional flexible strain sensors based on MXene-(Ti_(3)C_(2)T_(x)-)composited poly(vinyl alcohol)/polyvinyl pyrrolidone double-network hydrogels were prepared.The uniformly distributed hydrophilic MXene nanosheets formed a three-dimensional conductive network throughout the hydrogel,endowing the flexible sensor with high sensitivity.The strong interaction between the double-network hydrogel matrix and MXene greatly improved the mechanical properties of the hydrogels.The resulting nanocomposited hydrogels featured great tensile performance(2400%),toughness,and resilience.Particularly,the as-prepared flexible pressure sensor revealed ultrahigh sensitivity(10.75 kPa^(-1))with a wide response range(0-61.5 kPa),fast response(33.5 ms),and low limit of detection(0.87 Pa).Moreover,the hydrogel-based flexible sensors,with high sensitivity and durability,could be employed to monitor fullrange human motions and assembled into some aligned devices for subtle pressure detection,providing enormous potential in facial expression and phonation recognition,handwriting verification,healthy diagnosis,and wearable electronics.
基金the National Natural Science Foundation of China(62271485,61903363,U1811463,62103411,62203250)the Science and Technology Development Fund of Macao SAR(0093/2023/RIA2,0050/2020/A1)。
文摘DURING our discussion at workshops for writing“What Does ChatGPT Say:The DAO from Algorithmic Intelligence to Linguistic Intelligence”[1],we had expected the next milestone for Artificial Intelligence(AI)would be in the direction of Imaginative Intelligence(II),i.e.,something similar to automatic wordsto-videos generation or intelligent digital movies/theater technology that could be used for conducting new“Artificiofactual Experiments”[2]to replace conventional“Counterfactual Experiments”in scientific research and technical development for both natural and social studies[2]-[6].Now we have OpenAI’s Sora,so soon,but this is not the final,actually far away,and it is just the beginning.
基金Supported by National High Technology Project (863)(No. 2006AA02Z320)the National Natural Science Founda-tion of China (No.30700154, No.60874105)+1 种基金Zhejiang Natural Science Foundation (No.Y107458, RY1080422)the School Youth Found of Shanghai Jiaotong University
文摘Dempster-Shafer (DS) theory of evidence has been widely used in many data fusion ap- plication systems. However, how to determine basic probability assignment, which is the main and the first step in evidence theory, is still an open issue. In this paper, a new method to obtain Basic Probability Assignment (BPA) is proposed based on the similarity measure between generalized fuzzy numbers. In the proposed method, species model can be constructed by determination of the min, average and max value to construct a fuzzy number. Then, a new Radius Of Gravity (ROG) method to determine the similarity measure between generalized fuzzy numbers is used to calculate the BPA functions of each instance. Finally, the efficiency of the proposed method is illustrated by the classi- fication of Iris data.
基金financially supported by Brain Pool program funded by the Ministry of Science and ICT through the National Research Foundation of Korea (No.2021H1D3A2A01100019)the National Natural Science Foundation of China (No.62074057)+2 种基金Projects of Science and Technology Commission of Shanghai Municipality (Nos.19ZR1473800 and 18DZ2270800)the Open Research Projects of Zhejiang Lab (No.2021MCOAB06)the Postdoctoral Scientific Research Foundation of Qingdao
文摘Metal oxide semiconductor heterojunctions(MOSHs)can enhance the performance of ethanol gas sen-sors substantially.Ethanol gas sensors based on MOSHs are cost-effective and have excellent sensing response,good selectivity,fast response and recovery,long-term stability or repeatability,a low operating temperature,a facile fabrica-tion process,and versatile applications.This paper reviews the recent advances in gas sensors that are based on MOSHs and the advantages of using them to detect ethanol gas.According to the literature,compared with ethanol gas sen-sors that use single-component sensing materials,the MOSHs exhibit superior performance due to the synergy between the different components,which can amplify the reception and transduction components of the sensor signals.To the best of our knowledge,heterojunctions can be grouped into four main categories as metal oxide/metal oxide,metal oxide/metal sulfide,metal oxide/noble metal,and metal oxide/other materials,including rare-earth metals,g-C_(3)N_(4),and graphene,heterojunctions.The future trends and challenges that would be faced in the development of ethanol gas sensors based on MOSHs are discussed in detail.Finally,critical ideas and thinking regarding the future progress of MOSH-based gas sensors are presented.
基金supported by the Program of Introducing Talents of Discipline to Universities(111 Plan)of China(B14010)the National Natural Science Foundation of China(31727901)
文摘While moving ahead with the object detection technology, especially deep neural networks, many related tasks, such as medical application and industrial automation, have achieved great success. However, the detection of objects with multiple aspect ratios and scales is still a key problem. This paper proposes a top-down and bottom-up feature pyramid network(TDBU-FPN),which combines multi-scale feature representation and anchor generation at multiple aspect ratios. First, in order to build the multi-scale feature map, this paper puts a number of fully convolutional layers after the backbone. Second, to link neighboring feature maps, top-down and bottom-up flows are adopted to introduce context information via top-down flow and supplement suboriginal information via bottom-up flow. The top-down flow refers to the deconvolution procedure, and the bottom-up flow refers to the pooling procedure. Third, the problem of adapting different object aspect ratios is tackled via many anchor shapes with different aspect ratios on each multi-scale feature map. The proposed method is evaluated on the pattern analysis, statistical modeling and computational learning visual object classes(PASCAL VOC)dataset and reaches an accuracy of 79%, which exhibits a 1.8% improvement with a detection speed of 23 fps.
基金This work was supported in part by the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China(62022062)the National Natural Science Foundation of China(61974177,61674119)the Fundamental Research Funds for the Central Universities.
文摘The explosive growth of data and information has motivated various emerging non-von Neumann computational approaches in the More-than-Moore era.Photonics neuromorphic computing has attracted lots of attention due to the fascinating advantages such as high speed,wide bandwidth,and massive parallelism.Here,we offer a review on the optical neural computing in our research groups at the device and system levels.The photonics neuron and photonics synapse plasticity are presented.In addition,we introduce several optical neural computing architectures and algorithms including photonic spiking neural network,photonic convolutional neural network,photonic matrix computation,photonic reservoir computing,and photonic reinforcement learning.Finally,we summarize the major challenges faced by photonic neuromorphic computing,and propose promising solutions and perspectives.
基金the National Key Research and Development Program of China (2022YFB3803300)the open research fund of Songshan Lake Materials Laboratory (2021SLABFK02)the National Natural Science Foundation of China (21961160720)。
文摘Nowadays, the soar of photovoltaic performance of perovskite solar cells has set off a fever in the study of metal halide perovskite materials. The excellent optoelectronic properties and defect tolerance feature allow metal halide perovskite to be employed in a wide variety of applications. This article provides a holistic review over the current progress and future prospects of metal halide perovskite materials in representative promising applications, including traditional optoelectronic devices(solar cells, light-emitting diodes, photodetectors, lasers), and cutting-edge technologies in terms of neuromorphic devices(artificial synapses and memristors) and pressure-induced emission. This review highlights the fundamentals, the current progress and the remaining challenges for each application, aiming to provide a comprehensive overview of the development status and a navigation of future research for metal halide perovskite materials and devices.
基金This work was supported by National High Technology Research and Development Program of China(No.2014AA051901)the National Science Foundation of China(No.51377111).
文摘Active energy management is an effective way to realize the flexible utilization of distributed energy resources to suit the characteristics of active distribution system.Advanced active energy management strategies need to be designed to coordinate the optimization of‘generation,network,load’.An active management model is built for the local distribution system integrated with the generation curtailment mechanism and the charging/discharging management of plug-in electric vehicles.Furthermore,different strategies based on the energy management model are presented.The model and strategies are tested and discussed in a modified distribution system,and the impacts with different load profiles are also analyzed.
基金supported by the National Natural Science Foundation of China (61171194)
文摘This paper presents a method for detecting the small infrared target under complex background. An algorithm, named local mutation weighted information entropy （LMWIE）, is proposed to suppress background. Then, the grey value of targets is enhanced by calculating the local energy. Image segmentation based on the adaptive threshold is used to solve the problems that the grey value of noise is enhanced with the grey value improvement of targets. Experimental results show that compared with the adaptive Butterworth high-pass filter method, the proposed algorithm is more effective and faster for the infrared small target detection.
基金The authors acknowledge the use of the Australian National Fabrication Facility(ANFF),ACT Node.Rocio CamachoMorales acknowledges a grant from the Consejo Nacional de Ciencia y Tecnología(CONACYT),MexicoNikolay Dimitrov and Lyubomir Stoyanov acknowledge a grant from the EU Marie-Curie RISE program NOCTURNO+1 种基金Mohsen Rahmani acknowledges support from the UK Research and Innovation Future Leaders Fellowship(MR/T040513/1)Dragomir N.Neshev acknowledges a grant from the Australian Research Council(CE20010001,DP190101559).
文摘Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality control.Conventional infrared imaging technologies,however,require the use of materials such as narrow bandgap semiconductors,which are sensitive to thermal noise and often require cryogenic cooling.We demonstrate a compact all-optical alternative to perform infrared imaging in a metasurface composed of GaAs semiconductor nanoantennas,using a nonlinear wave-mixing process.We experimentally show the upconversion of short-wave infrared wavelengths via the coherent parametric process of sum-frequency generation.In this process,an infrared image of a target is mixed inside the metasurface with a strong pump beam,translating the image from the infrared to the visible in a nanoscale ultrathin imaging device.Our results open up new opportunities for the development of compact infrared imaging devices with applications in infrared vision and life sciences.
基金supported by the National Natural Science Foundation of China(Grant No.11704028)the National Key R&D Program of China(Grant No.2017YFB1104300).
文摘Numerous valuable studies on electron dynamics have focussed on the extraordinary properties of molybdenum disulfide(MoS_(2));however,most of them were confined to the level below the damage threshold.Here the electron dynamics of MoS_(2) under intense ultrafast laser irradiation was investigated by experiments and simulations.Two kinds of ablation mechanisms were revealed,which led to two distinct types of electron dynamics and final ablation morphology.At a higher fluence,the emergence of superheated liquid induced a dramatic change in the transient reflectivity and micro-honeycomb structures.At a lower fluence,the material was just removed by sublimation,and the ablation structure was relatively flat.X-ray photoelectron spectroscopic(XPS)measurements demonstrated that thermal decomposition only occurred at the higher fluence.Furthermore,a theoretical model was developed to deeply reveal the ultrafast dynamics of MoS_(2) ablation.The simulation results were in good agreement with the temporal and spatial reflectivity distribution obtained from the experiment.The electron and lattice temperature evolution was also obtained to prove the ablation mechanism.Our results revealed ultrafast dynamics of MoS_(2) above the damage threshold and are helpful for understanding the interaction mechanism between MoS_(2) and intense ultrafast lasers,as well as for MoS_(2) processing applications.
基金supported by the National Natural Science Foundation of China(Nos.61971045,61827901,61991451)National Key R&D Program(Grant No.2020YFB0505601)Fundamental Research Funds for the Central Universities(Grant No.3052019024).
文摘High-throughput computational imaging requires efficient processing algorithms to retrieve multi-dimensional and multi-scale information.In computational phase imaging,phase retrieval(PR)is required to reconstruct both amplitude and phase in complex space from intensity-only measurements.The existing PR algorithms suffer from the tradeoff among low computational complexity,robustness to measurement noise and strong generalization on different modalities.In this work,we report an efficient large-scale phase retrieval technique termed as LPR.It extends the plug-and-play generalized-alternating-projection framework from real space to nonlinear complex space.The alternating projection solver and enhancing neural network are respectively derived to tackle the measurement formation and statistical prior regularization.This framework compensates the shortcomings of each operator,so as to realize high-fidelity phase retrieval with low computational complexity and strong generalization.We applied the technique for a series of computational phase imaging modalities including coherent diffraction imaging,coded diffraction pattern imaging,and Fourier ptychographic microscopy.Extensive simulations and experiments validate that the technique outperforms the existing PR algorithms with as much as 17dB enhancement on signal-to-noise ratio,and more than one order-of-magnitude increased running efficiency.Besides,we for the first time demonstrate ultralarge-scale phase retrieval at the 8K level(7680×4320 pixels)in minute-level time.
