A new lateral insulated-gate bipolar transistor（LIGBT） with a SiO_2 shielded layer anode on SOI substrate is proposed and discussed.Compared to the conventional LIGBT,the proposed device offers an enhanced conductiv...A new lateral insulated-gate bipolar transistor（LIGBT） with a SiO_2 shielded layer anode on SOI substrate is proposed and discussed.Compared to the conventional LIGBT,the proposed device offers an enhanced conductivity modulation effect due to the SiO_2 shielded layer anode structure which can be formed by SIMOX technology.Simulation results show that,for the proposed LIGBT,during the conducting state,the electron-hole plasma concentrations in the n-drift region are several times larger than those of the conventional LIGBT;the conducting current is up to 37% larger than that of the conventional one.The enhanced conductivity modulation effect by SiO_2 shielded layer anode does not sacrifice other characteristics of the device,such as breakdown and switching,but is compatible with other optimized technologies.展开更多
The unmanned aerial vehicle(UAV)images captured under low-light conditions are often suffering from noise and uneven illumination.To address these issues,we propose a low-light image enhancement algorithm for UAV imag...The unmanned aerial vehicle(UAV)images captured under low-light conditions are often suffering from noise and uneven illumination.To address these issues,we propose a low-light image enhancement algorithm for UAV images,which is inspired by the Retinex theory and guided by a light weighted map.Firstly,we propose a new network for reflectance component processing to suppress the noise in images.Secondly,we construct an illumination enhancement module that uses a light weighted map to guide the enhancement process.Finally,the processed reflectance and illumination components are recombined to obtain the enhancement results.Experimental results show that our method can suppress the noise in images while enhancing image brightness,and prevent over enhancement in bright regions.Code and data are available at https://gitee.com/baixiaotong2/uav-images.git.展开更多
Medical image fusion technology is crucial for improving the detection accuracy and treatment efficiency of diseases,but existing fusion methods have problems such as blurred texture details,low contrast,and inability...Medical image fusion technology is crucial for improving the detection accuracy and treatment efficiency of diseases,but existing fusion methods have problems such as blurred texture details,low contrast,and inability to fully extract fused image information.Therefore,a multimodal medical image fusion method based on mask optimization and parallel attention mechanism was proposed to address the aforementioned issues.Firstly,it converted the entire image into a binary mask,and constructed a contour feature map to maximize the contour feature information of the image and a triple path network for image texture detail feature extraction and optimization.Secondly,a contrast enhancement module and a detail preservation module were proposed to enhance the overall brightness and texture details of the image.Afterwards,a parallel attention mechanism was constructed using channel features and spatial feature changes to fuse images and enhance the salient information of the fused images.Finally,a decoupling network composed of residual networks was set up to optimize the information between the fused image and the source image so as to reduce information loss in the fused image.Compared with nine high-level methods proposed in recent years,the seven objective evaluation indicators of our method have improved by 6%−31%,indicating that this method can obtain fusion results with clearer texture details,higher contrast,and smaller pixel differences between the fused image and the source image.It is superior to other comparison algorithms in both subjective and objective indicators.展开更多
Resistive switching random access memory(RRAM) is considered as one of the potential candidates for next-generation memory. However, obtaining an RRAM device with comprehensively excellent performance, such as high re...Resistive switching random access memory(RRAM) is considered as one of the potential candidates for next-generation memory. However, obtaining an RRAM device with comprehensively excellent performance, such as high retention and endurance, low variations, as well as CMOS compatibility, etc., is still an open question. In this work, we introduce an insert TaO_(x) layer into HfO_(x)-based RRAM to optimize the device performance. Attributing to robust filament formed in the TaO_(x) layer by a forming operation, the local-field and thermal enhanced effect and interface modulation has been implemented simultaneously. Consequently, the RRAM device features large windows(> 10^(3)), fast switching speed(-10 ns), steady retention(> 72h), high endurance(> 10^(8) cycles), and excellent uniformity of both cycle-to-cycle and device-to-device. These results indicate that inserting the TaO_(x) layer can significantly improve HfO_(x)-based device performance, providing a constructive approach for the practical application of RRAM.展开更多
Effective small object detection is crucial in various applications including urban intelligent transportation and pedestrian detection.However,small objects are difficult to detect accurately because they contain les...Effective small object detection is crucial in various applications including urban intelligent transportation and pedestrian detection.However,small objects are difficult to detect accurately because they contain less information.Many current methods,particularly those based on Feature Pyramid Network(FPN),address this challenge by leveraging multi-scale feature fusion.However,existing FPN-based methods often suffer from inadequate feature fusion due to varying resolutions across different layers,leading to suboptimal small object detection.To address this problem,we propose the Two-layerAttention Feature Pyramid Network(TA-FPN),featuring two key modules:the Two-layer Attention Module(TAM)and the Small Object Detail Enhancement Module(SODEM).TAM uses the attention module to make the network more focused on the semantic information of the object and fuse it to the lower layer,so that each layer contains similar semantic information,to alleviate the problem of small object information being submerged due to semantic gaps between different layers.At the same time,SODEM is introduced to strengthen the local features of the object,suppress background noise,enhance the information details of the small object,and fuse the enhanced features to other feature layers to ensure that each layer is rich in small object information,to improve small object detection accuracy.Our extensive experiments on challenging datasets such as Microsoft Common Objects inContext(MSCOCO)and Pattern Analysis Statistical Modelling and Computational Learning,Visual Object Classes(PASCAL VOC)demonstrate the validity of the proposedmethod.Experimental results show a significant improvement in small object detection accuracy compared to state-of-theart detectors.展开更多
We extend the third perturbation theory to study the polarization control behavior of the intermediate state absorption in Nd^（3＋）ions. The results show that coherent interference can occur between the single-photo...We extend the third perturbation theory to study the polarization control behavior of the intermediate state absorption in Nd^（3＋）ions. The results show that coherent interference can occur between the single-photon and three-photon excitation pathways, and depends on the central frequency of the femtosecond laser field. Moreover,single-photon and three-photon absorptions have different polarization control efficiencies, and the relative weight of three-photon absorption in the whole excitation processes can increase with increasing the laser intensity.Therefore, the enhancement or suppression of the intermediate state absorption can be realized and manipulated by properly designing the intensity and central frequency of the polarization modulated femtosecond laser field.This research can not only enrich theoretical research methods for the up-conversion luminescence manipulation of rare-earth ions, but also can provide a clear physical picture for understanding and controlling multi-photon absorption in a multiple energy level system.展开更多
With the development of fishery industry,accurate estimation of the number of fish in aquaculture waters is of great importance to fish behavior analysis,bait feeding and fishery resource investigation.In this paper,w...With the development of fishery industry,accurate estimation of the number of fish in aquaculture waters is of great importance to fish behavior analysis,bait feeding and fishery resource investigation.In this paper,we propose a method for fish density estimation based on the multi-scale context enhanced convolutional network,which could map a fish school image taken at any angle to a density map,and calculate the number of fish in the image finally.In order to eliminate the influence of camera perspective effect and image resolution on density estimation,multi-scale filters are utilized in a convolutional neural network to process fish image in parallel.And then,the context enhancement module is merged in the network structure to help the network understand the global context information of the image.Finally,different feature maps are merged together to construct the density map of fish school images,and finally get the number of fish in the image.In order to make the effectiveness of our method valid,we test the proposed method on DlouDataset.The results show that the proposed method has lower mean square error and mean absolute error,which is helpful to improve the accuracy of the fish counting in dense fish school images.展开更多
1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommuni...1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommunications applications, only a narrow bandwidth is required and thus resonantly enhancedMach-Zehndermodulators(RE-MZMs)have been developed to improve modulation efficiency at the expense of bandwidth.展开更多
Nonlinear optics(NLO)of transition metal dichalcogenides(TMDs)is promising for the on-chip photonic and optoelectronic applications.In this review,we will survey the current progress of NLO in TMDs.First,we will brief...Nonlinear optics(NLO)of transition metal dichalcogenides(TMDs)is promising for the on-chip photonic and optoelectronic applications.In this review,we will survey the current progress of NLO in TMDs.First,we will brief the basic theory of the NLO in TMDs.Second,several important nonlinear processes in TMDs such as harmonic generation,four-wave mixing,saturable absorption,and two-photon absorption will be presented and their potential applications are also discussed.Third,the main strategies to tune,modulate,and enhance the NLO in TMDs are reviewed,including the excitonic effect,symmetry modulation,optical cavity enhancement,valley selection,edge state,and material phase.Finally,we give an outlook regarding some important issues and directions of NLO in TMDs.展开更多
We report a direct, modulated bandwidth enhancement in a amplified feedback laser （AFL）, both experimen- tally and numerically. By means of fabricated devices, an enhanced -3 dB bandwidth of 27 GHz with an in-band f...We report a direct, modulated bandwidth enhancement in a amplified feedback laser （AFL）, both experimen- tally and numerically. By means of fabricated devices, an enhanced -3 dB bandwidth of 27 GHz with an in-band flatness of ±3 dB is experimentally confirmed at 13℃. It is numerically confirmed that the modulated bandwidth of the AFL can be enhanced to two times its original bandwidth, with more controlled flexibility to realize a flat, small-signal response.展开更多
In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolut...In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolution of the hologram reconstruction is affected by the point spread function(PSF) of the optical system. In this paper, we modulate the PSF by a spiral phase plate, which significantly enhances the lateral and depth resolution. We explain the theory for such resolution enhancement and show simulation results to verify the efficacy of the approach.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.60876053,60806025,60976060).
文摘A new lateral insulated-gate bipolar transistor（LIGBT） with a SiO_2 shielded layer anode on SOI substrate is proposed and discussed.Compared to the conventional LIGBT,the proposed device offers an enhanced conductivity modulation effect due to the SiO_2 shielded layer anode structure which can be formed by SIMOX technology.Simulation results show that,for the proposed LIGBT,during the conducting state,the electron-hole plasma concentrations in the n-drift region are several times larger than those of the conventional LIGBT;the conducting current is up to 37% larger than that of the conventional one.The enhanced conductivity modulation effect by SiO_2 shielded layer anode does not sacrifice other characteristics of the device,such as breakdown and switching,but is compatible with other optimized technologies.
基金supported by the National Natural Science Foundation of China(Nos.62201454 and 62306235)the Xi’an Science and Technology Program of Xi’an Science and Technology Bureau(No.23SFSF0004)。
文摘The unmanned aerial vehicle(UAV)images captured under low-light conditions are often suffering from noise and uneven illumination.To address these issues,we propose a low-light image enhancement algorithm for UAV images,which is inspired by the Retinex theory and guided by a light weighted map.Firstly,we propose a new network for reflectance component processing to suppress the noise in images.Secondly,we construct an illumination enhancement module that uses a light weighted map to guide the enhancement process.Finally,the processed reflectance and illumination components are recombined to obtain the enhancement results.Experimental results show that our method can suppress the noise in images while enhancing image brightness,and prevent over enhancement in bright regions.Code and data are available at https://gitee.com/baixiaotong2/uav-images.git.
基金supported by Gansu Natural Science Foundation Programme(No.24JRRA231)National Natural Science Foundation of China(No.62061023)Gansu Provincial Education,Science and Technology Innovation and Industry(No.2021CYZC-04)。
文摘Medical image fusion technology is crucial for improving the detection accuracy and treatment efficiency of diseases,but existing fusion methods have problems such as blurred texture details,low contrast,and inability to fully extract fused image information.Therefore,a multimodal medical image fusion method based on mask optimization and parallel attention mechanism was proposed to address the aforementioned issues.Firstly,it converted the entire image into a binary mask,and constructed a contour feature map to maximize the contour feature information of the image and a triple path network for image texture detail feature extraction and optimization.Secondly,a contrast enhancement module and a detail preservation module were proposed to enhance the overall brightness and texture details of the image.Afterwards,a parallel attention mechanism was constructed using channel features and spatial feature changes to fuse images and enhance the salient information of the fused images.Finally,a decoupling network composed of residual networks was set up to optimize the information between the fused image and the source image so as to reduce information loss in the fused image.Compared with nine high-level methods proposed in recent years,the seven objective evaluation indicators of our method have improved by 6%−31%,indicating that this method can obtain fusion results with clearer texture details,higher contrast,and smaller pixel differences between the fused image and the source image.It is superior to other comparison algorithms in both subjective and objective indicators.
基金supported by the National Key R&D Program of China under Grant No.2018YFA0701500the National Natural Science Foundation of China under Grant Nos.61825404,U20A20220,61732020,and 61851402+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDB44000000the China Postdoctoral Science Foundation under Grant No.2020M681167。
文摘Resistive switching random access memory(RRAM) is considered as one of the potential candidates for next-generation memory. However, obtaining an RRAM device with comprehensively excellent performance, such as high retention and endurance, low variations, as well as CMOS compatibility, etc., is still an open question. In this work, we introduce an insert TaO_(x) layer into HfO_(x)-based RRAM to optimize the device performance. Attributing to robust filament formed in the TaO_(x) layer by a forming operation, the local-field and thermal enhanced effect and interface modulation has been implemented simultaneously. Consequently, the RRAM device features large windows(> 10^(3)), fast switching speed(-10 ns), steady retention(> 72h), high endurance(> 10^(8) cycles), and excellent uniformity of both cycle-to-cycle and device-to-device. These results indicate that inserting the TaO_(x) layer can significantly improve HfO_(x)-based device performance, providing a constructive approach for the practical application of RRAM.
文摘Effective small object detection is crucial in various applications including urban intelligent transportation and pedestrian detection.However,small objects are difficult to detect accurately because they contain less information.Many current methods,particularly those based on Feature Pyramid Network(FPN),address this challenge by leveraging multi-scale feature fusion.However,existing FPN-based methods often suffer from inadequate feature fusion due to varying resolutions across different layers,leading to suboptimal small object detection.To address this problem,we propose the Two-layerAttention Feature Pyramid Network(TA-FPN),featuring two key modules:the Two-layer Attention Module(TAM)and the Small Object Detail Enhancement Module(SODEM).TAM uses the attention module to make the network more focused on the semantic information of the object and fuse it to the lower layer,so that each layer contains similar semantic information,to alleviate the problem of small object information being submerged due to semantic gaps between different layers.At the same time,SODEM is introduced to strengthen the local features of the object,suppress background noise,enhance the information details of the small object,and fuse the enhanced features to other feature layers to ensure that each layer is rich in small object information,to improve small object detection accuracy.Our extensive experiments on challenging datasets such as Microsoft Common Objects inContext(MSCOCO)and Pattern Analysis Statistical Modelling and Computational Learning,Visual Object Classes(PASCAL VOC)demonstrate the validity of the proposedmethod.Experimental results show a significant improvement in small object detection accuracy compared to state-of-theart detectors.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51132004,11474096,11604199,U1704145 and 11747101the Science and Technology Commission of Shanghai Municipality under Grant No 14JC1401500+1 种基金the Henan Provincial Natural Science Foundation of China under Grant No 182102210117the Higher Education Key Program of He’nan Province of China under Grant Nos 17A140025 and 16A140030
文摘We extend the third perturbation theory to study the polarization control behavior of the intermediate state absorption in Nd^（3＋）ions. The results show that coherent interference can occur between the single-photon and three-photon excitation pathways, and depends on the central frequency of the femtosecond laser field. Moreover,single-photon and three-photon absorptions have different polarization control efficiencies, and the relative weight of three-photon absorption in the whole excitation processes can increase with increasing the laser intensity.Therefore, the enhancement or suppression of the intermediate state absorption can be realized and manipulated by properly designing the intensity and central frequency of the polarization modulated femtosecond laser field.This research can not only enrich theoretical research methods for the up-conversion luminescence manipulation of rare-earth ions, but also can provide a clear physical picture for understanding and controlling multi-photon absorption in a multiple energy level system.
基金This work is supported by Institute of Marine Industry Technology of Universities in Liaoning Province(2018-CY-34)National Natural Science Foundation of China(31972846)+1 种基金China Postdoctoral Science Foundation(2018M640239)Acknowledgement for the Data Support from National Marine Science Data Center(Dalian),National Science&Technology Resource Sharing Service Platform of China(http://odc.dlou.edu.cn/).
文摘With the development of fishery industry,accurate estimation of the number of fish in aquaculture waters is of great importance to fish behavior analysis,bait feeding and fishery resource investigation.In this paper,we propose a method for fish density estimation based on the multi-scale context enhanced convolutional network,which could map a fish school image taken at any angle to a density map,and calculate the number of fish in the image finally.In order to eliminate the influence of camera perspective effect and image resolution on density estimation,multi-scale filters are utilized in a convolutional neural network to process fish image in parallel.And then,the context enhancement module is merged in the network structure to help the network understand the global context information of the image.Finally,different feature maps are merged together to construct the density map of fish school images,and finally get the number of fish in the image.In order to make the effectiveness of our method valid,we test the proposed method on DlouDataset.The results show that the proposed method has lower mean square error and mean absolute error,which is helpful to improve the accuracy of the fish counting in dense fish school images.
文摘1 IntroductionLiNbO3 optical modulators have become essential transmission devices for current and future wideband fibre-optic communications for both military and telecommunications applications. For many telecommunications applications, only a narrow bandwidth is required and thus resonantly enhancedMach-Zehndermodulators(RE-MZMs)have been developed to improve modulation efficiency at the expense of bandwidth.
基金support from National Natural Science Foundation of China(Grant no.61674060)the Fundamental Research Funds for the Central Universities,Huazhong University of Science and Technology(Grant no.2019kfyXJJS046,2017KFYXJJ030,2017KFXKJ003,2017KFXKJC002).
文摘Nonlinear optics(NLO)of transition metal dichalcogenides(TMDs)is promising for the on-chip photonic and optoelectronic applications.In this review,we will survey the current progress of NLO in TMDs.First,we will brief the basic theory of the NLO in TMDs.Second,several important nonlinear processes in TMDs such as harmonic generation,four-wave mixing,saturable absorption,and two-photon absorption will be presented and their potential applications are also discussed.Third,the main strategies to tune,modulate,and enhance the NLO in TMDs are reviewed,including the excitonic effect,symmetry modulation,optical cavity enhancement,valley selection,edge state,and material phase.Finally,we give an outlook regarding some important issues and directions of NLO in TMDs.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.61474111,61201103,61335009,61274045)the National973 Program of China(Grant No.2011CB301702)the National 863 Program of China(Grant No.2013AA014202)
文摘We report a direct, modulated bandwidth enhancement in a amplified feedback laser （AFL）, both experimen- tally and numerically. By means of fabricated devices, an enhanced -3 dB bandwidth of 27 GHz with an in-band flatness of ±3 dB is experimentally confirmed at 13℃. It is numerically confirmed that the modulated bandwidth of the AFL can be enhanced to two times its original bandwidth, with more controlled flexibility to realize a flat, small-signal response.
基金supported in part by the Research Grants Council of the Hong Kong Special Administrative Region,China, under project 7131–12Ethe NSFC RGC grant under project N–HKU714–13
文摘In optical scanning holography, one pupil produces a spherical wave and another produces a plane wave. They interfere with each other and result in a fringe pattern for scanning a three-dimensional object. The resolution of the hologram reconstruction is affected by the point spread function(PSF) of the optical system. In this paper, we modulate the PSF by a spiral phase plate, which significantly enhances the lateral and depth resolution. We explain the theory for such resolution enhancement and show simulation results to verify the efficacy of the approach.
