This study reviews the recent advances in data-driven polarimetric imaging technologies based on a wide range of practical applications.The widespread international research and activity in polarimetric imaging techni...This study reviews the recent advances in data-driven polarimetric imaging technologies based on a wide range of practical applications.The widespread international research and activity in polarimetric imaging techniques demonstrate their broad applications and interest.Polarization information is increasingly incorporated into convolutional neural networks(CNN)as a supplemental feature of objects to improve performance in computer vision task applications.Polarimetric imaging and deep learning can extract abundant information to address various challenges.Therefore,this article briefly reviews recent developments in data-driven polarimetric imaging,including polarimetric descattering,3D imaging,reflection removal,target detection,and biomedical imaging.Furthermore,we synthetically analyze the input,datasets,and loss functions and list the existing datasets and loss functions with an evaluation of their advantages and disadvantages.We also highlight the significance of data-driven polarimetric imaging in future research and development.展开更多
The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precip...The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precipitation, and runoff at 10 main hydrological and weather stations in the region. Our results show that a strong signal of climate shift from warm-dry to warm-humid in the western parts of northwestern China （Xinjiang） and the western Hexi Corridor of Gansu Province occurred in the late 1980s, and a same signal of climate change occurred in the mid-2000s in the source region of the Yellow River located in the eastern part of northwestern China. This climate changeover has led to a rapid increase in rainfall and stream runoff in the latter region. In most of the years since 2004 the average annual precipitation in the source region of the Yellow River has been greater than the long-term average annual value, and after 2007 the runoff measured at all of the hydrologic sections on the main channel of the Yellow River in the source region has also consistently exceeded the long-term average annual because of rainfall increase. It is difficult to determine the prospects of future climate change until additional observations and research are conducted on the rate and temporal and spatial extents of climate change in the region. Nevertheless, we predict that the climate shift from warm-dry to warm-humid in the source region of the Yellow River is very likely to be in the decadal time scale, which means a warming and rainy climate in the source region of the Yellow River will continue in the coming decades.展开更多
In the era of information explosion,the demand of data storage is increased dramatically.Holographic data storage technology is one of the most promising next-generation data storage technologies due to its high stora...In the era of information explosion,the demand of data storage is increased dramatically.Holographic data storage technology is one of the most promising next-generation data storage technologies due to its high storage density,fast data transfer rate,long data life time and less energy consumption.Collinear holographic data storage technology is the typical solution of the holographic data storage technology which owns a more compact,compatible and practical system.This paper gives a brief review of holographic data storage,introduces collinear holographic data storage technology and discusses phase modulation technology being used in the holographic data storage system to achieve higher storage density and higher data transfer rate.展开更多
Due to its lead-free composition and a unique double polarization hysteresis loop with a large maximum polarization(Pmax)and a small remnant polarization(Pr),AgNbO_(3)-based antiferroelectrics(AFEs)have attracted exte...Due to its lead-free composition and a unique double polarization hysteresis loop with a large maximum polarization(Pmax)and a small remnant polarization(Pr),AgNbO_(3)-based antiferroelectrics(AFEs)have attracted extensive research interest for electric energy storage applications.However,a low dielectric breakdown field(Eb)limits an energy density and its further development.In this work,a highly efficient method was proposed to fabricate high-energy-density Ag(Nb,Ta)O_(3) capacitor films on Si substrates,using a two-step process combining radio frequency(RF)-magnetron sputtering at 450℃and post-deposition rapid thermal annealing(RTA).The RTA process at 700℃led to sufficient crystallization of nanograins in the film,hindering their lateral growth by employing short annealing time of 5 min.The obtained Ag(Nb,Ta)O_(3) films showed an average grain size(D)of~14 nm(obtained by Debye-Scherrer formula)and a slender room temperature(RT)polarization-electric field(P-E)loop(Pr≈3.8 mC·cm^(−2) and P_(max)≈38 mC·cm^(−2) under an electric field of~3.3 MV·cm^(−1)),the P-E loop corresponding to a high recoverable energy density(W_(rec))of~46.4 J·cm^(−3) and an energy efficiency(η)of~80.3%.Additionally,by analyzing temperature-dependent dielectric property of the film,a significant downshift of the diffused phase transition temperature(T_(M2-M3))was revealed,which indicated the existence of a stable relaxor-like AFE phase near the RT.The downshift of the T_(M2-M3) could be attributed to a nanograin size and residual tensile strain of the film,and it led to excellent temperature stability(20-240℃)of the energy storage performance of the film.Our results indicate that the Ag(Nb,Ta)O_(3) film is a promising candidate for electrical energy storage applications.展开更多
This paper presents a polarization descattering imaging method for underwater detection in which the targets have nonuniform polarization characteristics. The core of this method takes the nonuniform distribution of t...This paper presents a polarization descattering imaging method for underwater detection in which the targets have nonuniform polarization characteristics. The core of this method takes the nonuniform distribution of the polarization information of the target-reflected light into account and expands the application field of underwater polarization imaging.Independent component analysis was used to separate the target light and backscattered light. Theoretical analysis and proof-of-concept experiments were employed to demonstrate the effectiveness of the proposed method in estimating target information. The proposed method showed superiority in accurately estimating the target information compared with other polarization imaging methods.展开更多
Ten nitrated polycyclic aromatic hydrocarbons(nPAHs)and 4 oxygenated polycyclic aromatic hydrocarbons(oPAHs)in fine particulate matter(PM2.5)samples from Mount Tai were analyzed during summer(June to August),2015.Duri...Ten nitrated polycyclic aromatic hydrocarbons(nPAHs)and 4 oxygenated polycyclic aromatic hydrocarbons(oPAHs)in fine particulate matter(PM2.5)samples from Mount Tai were analyzed during summer(June to August),2015.During the observation campaign,themean concentration of total nPAHs and oPAHs was 31.62 pg/m^(3)and 0.15 ng/m^(3),respectively.Two of the monitored compounds,namely 9-nitro-anthracene(9N-ANT)(6.86 pg/m^(3))and 9-fluorenone(9FO)(0.05 ng/m^(3))were the predominant compounds of nPAHs and oPAHs,respectively.The potential source and long-range transportation of nPAHs and oPAHs were investigated by the positive matrix factorization(PMF)method and the potential source contribution function(PSCF)methods.The results revealed that biomass/coal burning,gasoline vehicle emission,diesel vehicle emission and secondary formation were the dominant sources of nPAHs and oPAHs,which were mainly from Henan province and Beijing-Tianjin-Hebei region and Bohai sea.The incremental life cancer risk(ILCR)values were calculated to evaluate the exposure risk of nPAHs and oPAHs for three group people(infant,children and adult),and the values of ILCR were 7.02×10^(−10),3.49×10^(−9)and 1.41×10^(−8)for infant,children and adults,respectively.All these values were lower than the standard of EPA(Environmental Protection Agency)(<10−6),indicating acceptable health risk of nPAHs and oPAHs.展开更多
Achieving an excellent energy storage performance,together with high cycling reliability,is desirable for expanding technological applications of ferroelectric dielectrics.However,in well-crystallized ferroelectric ma...Achieving an excellent energy storage performance,together with high cycling reliability,is desirable for expanding technological applications of ferroelectric dielectrics.However,in well-crystallized ferroelectric materials,the concomitant high polarizability and low polarization saturation field have led to a square-shaped polarization–electric field loop,fatally impairing both recoverable energy density(W_(rec))and efficiency(η).Nanocrystalline ferroelectric films with a macroscopically amorphous structure have shown an improved W_(rec) andη,but their much lower polarizability demands an extremely high electric field to achieve such performances,which is undesirable from an economic viewpoint.Here,we propose a strategy to boost the energy storage performances and stability of ferroelectric capacitors simultaneously by constructing a tri-layer film in which a well-crystallized ferroelectric layer was sandwiched by two pseudo-linear dielectric layers with a dominant amorphous structure.In sol–gel-derived BaTiO_(3)/(Pb,La,Ca)TiO_(3)/BaTiO_(3)(BTO/PLCT/BTO)tri-layer films,we show that the above design is realized via rapid thermal annealing which fully crystallized the middle PLCT layer while left the top/bottom BTO cap layers in a poor crystallization status.This sandwiched structure is endowed with an enhanced maximum polarization while a small remnant one and a much-delayed polarization saturation,which corresponds to large W_(rec)≈80 J/cm^(3) and highη≈86%.Furthermore,the film showed an outstanding cycling stability:its W_(rec) andηremain essentially unchanged after 10^(9) electric cycles(DW/W<4%,Dη/η<2%).These good energy storage characteristics have proved the effectiveness of our proposed strategy,paving a way for the utilization of sandwiched films in applications of electric power systems and advanced pulsed-discharge devices.展开更多
We propose four-level phase pair encoding and decoding with single interferometric phase retrieval for holographic data storage. Inherent with phase pair encoding, phase shifting is generated by assigning a certain ph...We propose four-level phase pair encoding and decoding with single interferometric phase retrieval for holographic data storage. Inherent with phase pair encoding, phase shifting is generated by assigning a certain phase difference between two pixels of the phase pair. Multiple phase shifting operations are not required. In addition, a phase-readout reference beam can be a plane beam with an arbitrary phase in our method because phase shifting can be encoded on the phase-only spatial light modulator easily and accurately. Therefore, our method can not only increase the data transfer rate, but also improve the robustness of the holographic data storage system. Although the code rate of our method needs to be sacrificed by half, the code rate is still twice that of amplitude code when four-level phase encoding is used. We demonstrated experimentally that there is only a 1×10^-2 order of bit error rate before error correcting, which is acceptable. We believe our method will further advance the phase-modulated holographic data storage technique.展开更多
We investigate Hoeffding's inequality for both discrete-time Markov chains and continuous-time Markov processes on a general state space. Our results relax the usual aperiodicity restriction in the literature, and...We investigate Hoeffding's inequality for both discrete-time Markov chains and continuous-time Markov processes on a general state space. Our results relax the usual aperiodicity restriction in the literature, and the explicit upper bounds in the inequalities are obtained via the solution of Poisson's equation. The results are further illustrated with applications to queueing theory and reective diffusion processes.展开更多
High-resolution imaging through randomly dynamic scattered fields and highly scattered walls is an extensively sought-after capability with potential applications in various fields such as underwater imaging,biomedica...High-resolution imaging through randomly dynamic scattered fields and highly scattered walls is an extensively sought-after capability with potential applications in various fields such as underwater imaging,biomedical imaging,and seeing through fog.Numerous methods have been proposed to unscramble object information from degraded scattered images,resulting in considerable improvements in image contrast in degraded scenarios[1].展开更多
基金support from the National Natural Science Foundation of China(Nos.62205259,62075175,61975254,62375212,62005203 and 62105254)the Open Research Fund of CAS Key Laboratory of Space Precision Measurement Technology(No.B022420004)the Fundamental Research Funds for the Central Universities(No.ZYTS23125).
文摘This study reviews the recent advances in data-driven polarimetric imaging technologies based on a wide range of practical applications.The widespread international research and activity in polarimetric imaging techniques demonstrate their broad applications and interest.Polarization information is increasingly incorporated into convolutional neural networks(CNN)as a supplemental feature of objects to improve performance in computer vision task applications.Polarimetric imaging and deep learning can extract abundant information to address various challenges.Therefore,this article briefly reviews recent developments in data-driven polarimetric imaging,including polarimetric descattering,3D imaging,reflection removal,target detection,and biomedical imaging.Furthermore,we synthetically analyze the input,datasets,and loss functions and list the existing datasets and loss functions with an evaluation of their advantages and disadvantages.We also highlight the significance of data-driven polarimetric imaging in future research and development.
基金supported by the Key Deployment Project of the Chinese Academy of Sciences (Grant No. Y322G73001)the Major Research Projects of the National Natural Science Fund Project (Grant No. 91225302)the National Natural Science Foundation of China (NSFC) (Grant Nos. 41240002 and 91225301)
文摘The change characteristics and trends of the regional climate in the source region of the Yellow River, and the response of runoff to climate change, are analyzed based on observational data of air temperature, precipitation, and runoff at 10 main hydrological and weather stations in the region. Our results show that a strong signal of climate shift from warm-dry to warm-humid in the western parts of northwestern China （Xinjiang） and the western Hexi Corridor of Gansu Province occurred in the late 1980s, and a same signal of climate change occurred in the mid-2000s in the source region of the Yellow River located in the eastern part of northwestern China. This climate changeover has led to a rapid increase in rainfall and stream runoff in the latter region. In most of the years since 2004 the average annual precipitation in the source region of the Yellow River has been greater than the long-term average annual value, and after 2007 the runoff measured at all of the hydrologic sections on the main channel of the Yellow River in the source region has also consistently exceeded the long-term average annual because of rainfall increase. It is difficult to determine the prospects of future climate change until additional observations and research are conducted on the rate and temporal and spatial extents of climate change in the region. Nevertheless, we predict that the climate shift from warm-dry to warm-humid in the source region of the Yellow River is very likely to be in the decadal time scale, which means a warming and rainy climate in the source region of the Yellow River will continue in the coming decades.
基金We are grateful for financial supports from National Key R&D Program of China(2018YFA0701800)National Natural Science Foundation of China(Grant No.61475019).
文摘In the era of information explosion,the demand of data storage is increased dramatically.Holographic data storage technology is one of the most promising next-generation data storage technologies due to its high storage density,fast data transfer rate,long data life time and less energy consumption.Collinear holographic data storage technology is the typical solution of the holographic data storage technology which owns a more compact,compatible and practical system.This paper gives a brief review of holographic data storage,introduces collinear holographic data storage technology and discusses phase modulation technology being used in the holographic data storage system to achieve higher storage density and higher data transfer rate.
基金support from the National Natural Science Foundation of China (Grant Nos.51772175,52072218,and 52002192)Natural Science Foundation of Shandong Province (Grant Nos.ZR2020QE042,ZR2022ZD39,and ZR2022ME031)+6 种基金the Science,Education and Industry Integration Pilot Projects of Qilu University of Technology (Shandong Academy of Sciences) (Grant Nos.2022GH018 and 2022PY055)support from the Jinan City Science and Technology Bureau (Grant No.2021GXRC055)the Education Department of Hunan Province/Xiangtan University (Grant No.KZ0807969)funding for top talents at Qilu University of Technology (Shandong Academy of Sciences)support from the Jiangsu Province NSFC (Grant No.BK20180764)support from the National Key R&D Program of China (Grant No.2021YFB3601504)Natural Science Foundation of Shandong Province (Grant No.ZR2020KE019).
文摘Due to its lead-free composition and a unique double polarization hysteresis loop with a large maximum polarization(Pmax)and a small remnant polarization(Pr),AgNbO_(3)-based antiferroelectrics(AFEs)have attracted extensive research interest for electric energy storage applications.However,a low dielectric breakdown field(Eb)limits an energy density and its further development.In this work,a highly efficient method was proposed to fabricate high-energy-density Ag(Nb,Ta)O_(3) capacitor films on Si substrates,using a two-step process combining radio frequency(RF)-magnetron sputtering at 450℃and post-deposition rapid thermal annealing(RTA).The RTA process at 700℃led to sufficient crystallization of nanograins in the film,hindering their lateral growth by employing short annealing time of 5 min.The obtained Ag(Nb,Ta)O_(3) films showed an average grain size(D)of~14 nm(obtained by Debye-Scherrer formula)and a slender room temperature(RT)polarization-electric field(P-E)loop(Pr≈3.8 mC·cm^(−2) and P_(max)≈38 mC·cm^(−2) under an electric field of~3.3 MV·cm^(−1)),the P-E loop corresponding to a high recoverable energy density(W_(rec))of~46.4 J·cm^(−3) and an energy efficiency(η)of~80.3%.Additionally,by analyzing temperature-dependent dielectric property of the film,a significant downshift of the diffused phase transition temperature(T_(M2-M3))was revealed,which indicated the existence of a stable relaxor-like AFE phase near the RT.The downshift of the T_(M2-M3) could be attributed to a nanograin size and residual tensile strain of the film,and it led to excellent temperature stability(20-240℃)of the energy storage performance of the film.Our results indicate that the Ag(Nb,Ta)O_(3) film is a promising candidate for electrical energy storage applications.
基金This work was supported by the Key Laboratory of Optical Engineering,Chinese Academy of Sciences(No.QC20191097)the National Natural Science Foundation of China(NSFC)(Nos.62075175 and 62005203).
文摘This paper presents a polarization descattering imaging method for underwater detection in which the targets have nonuniform polarization characteristics. The core of this method takes the nonuniform distribution of the polarization information of the target-reflected light into account and expands the application field of underwater polarization imaging.Independent component analysis was used to separate the target light and backscattered light. Theoretical analysis and proof-of-concept experiments were employed to demonstrate the effectiveness of the proposed method in estimating target information. The proposed method showed superiority in accurately estimating the target information compared with other polarization imaging methods.
基金supported by the China Postdoctoral Science Foundation(No.2020M670667)the Tianjin Municipal Education Commission Research Project(No.2017KJ244)+1 种基金the Key Research and Development Plan of Tianjin(No.18YFZCSF01400)the National Natural Science Foundation of China(Nos.41701579,21806158).
文摘Ten nitrated polycyclic aromatic hydrocarbons(nPAHs)and 4 oxygenated polycyclic aromatic hydrocarbons(oPAHs)in fine particulate matter(PM2.5)samples from Mount Tai were analyzed during summer(June to August),2015.During the observation campaign,themean concentration of total nPAHs and oPAHs was 31.62 pg/m^(3)and 0.15 ng/m^(3),respectively.Two of the monitored compounds,namely 9-nitro-anthracene(9N-ANT)(6.86 pg/m^(3))and 9-fluorenone(9FO)(0.05 ng/m^(3))were the predominant compounds of nPAHs and oPAHs,respectively.The potential source and long-range transportation of nPAHs and oPAHs were investigated by the positive matrix factorization(PMF)method and the potential source contribution function(PSCF)methods.The results revealed that biomass/coal burning,gasoline vehicle emission,diesel vehicle emission and secondary formation were the dominant sources of nPAHs and oPAHs,which were mainly from Henan province and Beijing-Tianjin-Hebei region and Bohai sea.The incremental life cancer risk(ILCR)values were calculated to evaluate the exposure risk of nPAHs and oPAHs for three group people(infant,children and adult),and the values of ILCR were 7.02×10^(−10),3.49×10^(−9)and 1.41×10^(−8)for infant,children and adults,respectively.All these values were lower than the standard of EPA(Environmental Protection Agency)(<10−6),indicating acceptable health risk of nPAHs and oPAHs.
基金The authors are deeply grateful for the financial support from the National Natural Science Foundation of China(NSFC)(Grant Nos.52002192,51772175,and 52072150)the Natural Science Foundation of Shandong Province(Grant Nos.ZR2020QE042,ZR2022ZD39,ZR2022ME031,ZR2022ME075,and ZR2022QB138)+3 种基金the Science,Education and Industry Integration Pilot Projects of Qilu University of Technology(Shandong Academy of Sciences)(Grant Nos.2022PY055 and 2022GH018)Jun Ouyang acknowledges the support from the Jinan City Science and Technology Bureau(Grant No.2021GXRC055)the Education Department of Hunan Province/Xiangtan University(Grant No.KZ0807969)the Seed Funding for Top Talents at Qilu University of Technology(Shandong Academy of Sciences).
文摘Achieving an excellent energy storage performance,together with high cycling reliability,is desirable for expanding technological applications of ferroelectric dielectrics.However,in well-crystallized ferroelectric materials,the concomitant high polarizability and low polarization saturation field have led to a square-shaped polarization–electric field loop,fatally impairing both recoverable energy density(W_(rec))and efficiency(η).Nanocrystalline ferroelectric films with a macroscopically amorphous structure have shown an improved W_(rec) andη,but their much lower polarizability demands an extremely high electric field to achieve such performances,which is undesirable from an economic viewpoint.Here,we propose a strategy to boost the energy storage performances and stability of ferroelectric capacitors simultaneously by constructing a tri-layer film in which a well-crystallized ferroelectric layer was sandwiched by two pseudo-linear dielectric layers with a dominant amorphous structure.In sol–gel-derived BaTiO_(3)/(Pb,La,Ca)TiO_(3)/BaTiO_(3)(BTO/PLCT/BTO)tri-layer films,we show that the above design is realized via rapid thermal annealing which fully crystallized the middle PLCT layer while left the top/bottom BTO cap layers in a poor crystallization status.This sandwiched structure is endowed with an enhanced maximum polarization while a small remnant one and a much-delayed polarization saturation,which corresponds to large W_(rec)≈80 J/cm^(3) and highη≈86%.Furthermore,the film showed an outstanding cycling stability:its W_(rec) andηremain essentially unchanged after 10^(9) electric cycles(DW/W<4%,Dη/η<2%).These good energy storage characteristics have proved the effectiveness of our proposed strategy,paving a way for the utilization of sandwiched films in applications of electric power systems and advanced pulsed-discharge devices.
基金supported by the National Natural Science Foundation of China(Nos.61475019 and 61505006)
文摘We propose four-level phase pair encoding and decoding with single interferometric phase retrieval for holographic data storage. Inherent with phase pair encoding, phase shifting is generated by assigning a certain phase difference between two pixels of the phase pair. Multiple phase shifting operations are not required. In addition, a phase-readout reference beam can be a plane beam with an arbitrary phase in our method because phase shifting can be encoded on the phase-only spatial light modulator easily and accurately. Therefore, our method can not only increase the data transfer rate, but also improve the robustness of the holographic data storage system. Although the code rate of our method needs to be sacrificed by half, the code rate is still twice that of amplitude code when four-level phase encoding is used. We demonstrated experimentally that there is only a 1×10^-2 order of bit error rate before error correcting, which is acceptable. We believe our method will further advance the phase-modulated holographic data storage technique.
基金This work was supported in part by the National Natural Science Foundation of China(Grant Nos.11971486,11771452)the Natural Science Foundation of Hunan Province(Grant Nos.2019JJ40357,2020JJ4674)the Innovation Program of Central South University(Grant No.2020zzts039).
文摘We investigate Hoeffding's inequality for both discrete-time Markov chains and continuous-time Markov processes on a general state space. Our results relax the usual aperiodicity restriction in the literature, and the explicit upper bounds in the inequalities are obtained via the solution of Poisson's equation. The results are further illustrated with applications to queueing theory and reective diffusion processes.
文摘High-resolution imaging through randomly dynamic scattered fields and highly scattered walls is an extensively sought-after capability with potential applications in various fields such as underwater imaging,biomedical imaging,and seeing through fog.Numerous methods have been proposed to unscramble object information from degraded scattered images,resulting in considerable improvements in image contrast in degraded scenarios[1].
