We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby R...We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary.展开更多
It is a challenge in the field sampling to face conflict between the statistical requirements and the logistical constraints when explicitly estimating the macrobenthos species richness in the heterogeneous intertidal...It is a challenge in the field sampling to face conflict between the statistical requirements and the logistical constraints when explicitly estimating the macrobenthos species richness in the heterogeneous intertidal wetlands. To solve this problem, this study tried to design an optimal, efficient and practical sampling strategy by comprehensively focusing on the three main parts of the entire process(to optimize the sampling method, to determine the minimum sampling effort and to explore the proper sampling interval) in a typical intertidal wetland of the Changjiang(Yangtze) Estuary, China. Transect sampling was selected and optimized by stratification based on pronounced habitat types(tidal flat, tidal creek, salt marsh vegetation). This type of sampling is also termed within-transect stratification sampling. The optimal sampling intervals and the minimum sample effort were determined by two beneficial numerical methods: Monte Carlo simulations and accumulative species curves. The results show that the within-transect stratification sampling with typical habitat types was effective for encompassing 81% of the species, suggesting that this type of sampling design can largely reduce the sampling effort and labor. The optimal sampling intervals and minimum sampling efforts for three habitats were determined: sampling effort must exceed 1.8 m^2 by 10 m intervals in the salt marsh vegetation, 2 m^2 by 10 m intervals in the tidal flat, and 3 m^2 by 1 m intervals in the tidal creek habitat. It was suggested that the differences were influenced by the mobility range of the dominant species and the habitats' physical differences(e.g., tidal water, substrate, vegetation cover). The optimized sampling strategy could provide good precision in the richness estimation of macrobenthos and balance the sampling effort. Moreover, the conclusions presented here provide a reference for recommendations to consider before macrobenthic surveys take place in estuarine wetlands. The sampling strategy, focusing on the three key parts of the sampling design, had a good operational effect and could be used as a guide for field sampling for habitat management or ecosystem assessment.展开更多
Shape-induced phase transition of vortex domain structures(VDSs)in BaTiO_3(BT)nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method.Our calculation indicates the t...Shape-induced phase transition of vortex domain structures(VDSs)in BaTiO_3(BT)nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method.Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet.Interestingly,a novel VDS is found in BT nanoplatelets in our simulations.Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot.Furthermore,based on the novel VDS,routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed.In particular,our results show the possibility of designing multi-states devices based on a single VDS.展开更多
Reversible data hiding in encrypted image(RDHEI)is a widely used technique for privacy protection,which has been developed in many applications that require high confidentiality,authentication and integrity.Proposed R...Reversible data hiding in encrypted image(RDHEI)is a widely used technique for privacy protection,which has been developed in many applications that require high confidentiality,authentication and integrity.Proposed RDHEI methods do not allow high embedding rate while ensuring losslessly recover the original image.Moreover,the ciphertext form of encrypted image in RDHEI framework is easy to cause the attention of attackers.This paper proposes a reversible data hiding algorithm based on image camouflage encryption and bit plane compression.A camouflage encryption algorithm is used to transform a secret image into another meaningful target image,which can cover both secret image and encryption behavior based on“plaintext to plaintext”transformation.An edge optimization method based on prediction algorithm is designed to improve the image camouflage encryption quality.The reversible data hiding based bit-plane level compression,which can improve the redundancy of the bit plane by Gray coding,is used to embed watermark in the camouflage image.The experimental results also show the superior performance of the method in terms of embedding capacity and image quality.展开更多
Objective and Impact Statement.Distinguishing malignant lymphocytes from normal ones is vital in pathological examination.We proposed an inverse light scattering(ILS)method for label-free suspended lymphocytes with co...Objective and Impact Statement.Distinguishing malignant lymphocytes from normal ones is vital in pathological examination.We proposed an inverse light scattering(ILS)method for label-free suspended lymphocytes with complex fine structures to identify their volumes for pathological state.Introduction.Light scattering as cell’s“fingerprint”provides valuable morphology information closely related to its biophysical states.However,the detail relationships between the morphology with complex fine structures and its scattering characters are not fully understood.Methods.To quantitatively inverse the volumes of membrane and nucleus as the main scatterers,clinical lymphocyte morphologies were modeled combining the Gaussian random sphere geometry algorithm by 750 reconstructed results after confocal scanning,which allowed the accurate simulation to solve ILS problem.For complex fine structures,the specificity for ILS study was firstly discussed(to our knowledge)considering the differences of not only surface roughness,posture,but also the ratio of nucleus to the cytoplasm and refractive index.Results.The volumes of membrane and nucleus were proved theoretically to have good linear relationship with the effective area and entropy of forward scattering images.Their specificity deviations were less than 3.5%.Then,our experimental results for microsphere and clinical leukocytes showed the Pearson product-moment correlation coefficients(PPMCC)of this linear relationship were up to 0.9830~0.9926.Conclusion.Our scattering inversion method could be effectively applied to identify suspended label-free lymphocytes without destructive sample pretreatments and complex experimental systems.展开更多
Slow strain rate test(SSRT)and tensile fracture observation are applied to study the stress corrosion cracking(SCC)of L360NS pipeline steel.5.0 wt.%sodium chloride solution containing elemental sulfur and 0.5 wt.%glac...Slow strain rate test(SSRT)and tensile fracture observation are applied to study the stress corrosion cracking(SCC)of L360NS pipeline steel.5.0 wt.%sodium chloride solution containing elemental sulfur and 0.5 wt.%glacial acetic acid solution containing elemental sulfur are used.The results show that brittle fracture mainly occurs on the samples in high sulfur environment.In the sulfur suspension solution,the SCC sensitivity of L360NS pipeline steel increases along elemental sulfur content.In sulfur melting cladding condition,obvious corrosion can be observed with a large amount of corrosion pits appearing on the gauge section of the sample.The corrosion products are Fe1txS,black easily detached,and H2.In sulfur suspension and sulfur melting cladding conditions,stress oriented hydrogen induced cracking(SOHIC)is the main cracking,which is caused by the joint effect of SCC and hydrogen induced cracking(HIC).展开更多
Mechanical control of ferroelectric domain evolution has attracted much interest over the past decade.Nevertheless,bidirectional 180°mechanical switching,i.e.,a complete cycle of mechanical writing and then erasi...Mechanical control of ferroelectric domain evolution has attracted much interest over the past decade.Nevertheless,bidirectional 180°mechanical switching,i.e.,a complete cycle of mechanical writing and then erasing of a ferroelectric nanodomain,has not yet been realized in tip-film architectures.Here,via first-principles-based molecular dynamics simulations,we demonstrate that bidirectional 180°mechanical switching is possible in tip-film architectures when screening condition of ferroelectric films and tip loading force are within an appropriate window.The switching utilizes a delicate competition between the flexoelectric field and an overlooked effective dipolar field.The effective dipolar field dominates at small tip force and trigger switching from a downward single-domain state to an upward poly-domain state,whereas the flexoelectric field dominates at relatively large tip force and enables a back-switching.Bidirectional mechanical switching is achieved by applying tip force pulses with alternatively varying strength.The dipole-dipole interaction dynamics play important roles in mechanical switching.展开更多
The toroidal order of electric dipoles in ferroelectric materials has attracted attention in the past decade due to fascinating properties and great potential for enabling novel memory devices,and functional devices i...The toroidal order of electric dipoles in ferroelectric materials has attracted attention in the past decade due to fascinating properties and great potential for enabling novel memory devices,and functional devices in general.However,facile manipulation of toroidal order in ferroelectrics remains challenging.Here,using first-principles derived simulations,we demonstrate an efficient scheme to control the polar-toroidal multi-order(PTMO)states in ferroelectric nanowires.Two feasible strategies of controlling PTMO states by a combination of homogeneous electric field and torque are carried out in ferroelectric/paraelectric composite nanowires.This is possible based on trilinear coupling between polarization,toroidization and the twist force.As a result,switching of the toroidization of the nanowire can be readily achieved by reversal of the axial polarization.The torque threshold needed to control PTMO states is also calculated and found to be relatively small,indicating the feasibility of this method.Our study demonstrates facile control of PTMO states,including ferroelectric skyrmions,in ferroelectrics and is a step towards designing ferroelectric devices based on multi-order states.展开更多
文摘We conducted experiments in an artificial stream tank with wild juvenile Chinese sturgeon Acipenser sinensis captured in the Yangtze Estuary to test the null hypothesis that their feeding efficiency on Barcheek goby Rhinogobius giurinus was not affected by sand vs. smooth glass substrate. Gobies are among the most common prey eaten by wild juvenile A. sinensis in the estuary. Test results found neither substrate type significantly affected feeding efficiency by juveniles. Previous research found a strong innate habitat preference of A. sinensis for sand substrate. The present results indicate that the preference for sand is not related to efficiently capturing R. giurinus on sand, but is an adaptation predisposing juvenile A. sinensis to seek sandy substrate where R. giurinus and other benthic forage are the most abundant in the Yangtze Estuary.
基金This work was financially supported by the National Key R&D Program of China(No.2017YFA0205004)the Anhui Initiative in Quantum Information Technologies(AHY090000)+1 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB36020200)the National Natural Science Foundation of China(No.11620101003,No.11904349,and No.21972129).
基金The Special Scientific Research Funds for Central Non-profit Institutes(East China Sea Fisheries Research Institute)under contract No.2016T08the National Natural Science Foundation of China under contract No.31400410
文摘It is a challenge in the field sampling to face conflict between the statistical requirements and the logistical constraints when explicitly estimating the macrobenthos species richness in the heterogeneous intertidal wetlands. To solve this problem, this study tried to design an optimal, efficient and practical sampling strategy by comprehensively focusing on the three main parts of the entire process(to optimize the sampling method, to determine the minimum sampling effort and to explore the proper sampling interval) in a typical intertidal wetland of the Changjiang(Yangtze) Estuary, China. Transect sampling was selected and optimized by stratification based on pronounced habitat types(tidal flat, tidal creek, salt marsh vegetation). This type of sampling is also termed within-transect stratification sampling. The optimal sampling intervals and the minimum sample effort were determined by two beneficial numerical methods: Monte Carlo simulations and accumulative species curves. The results show that the within-transect stratification sampling with typical habitat types was effective for encompassing 81% of the species, suggesting that this type of sampling design can largely reduce the sampling effort and labor. The optimal sampling intervals and minimum sampling efforts for three habitats were determined: sampling effort must exceed 1.8 m^2 by 10 m intervals in the salt marsh vegetation, 2 m^2 by 10 m intervals in the tidal flat, and 3 m^2 by 1 m intervals in the tidal creek habitat. It was suggested that the differences were influenced by the mobility range of the dominant species and the habitats' physical differences(e.g., tidal water, substrate, vegetation cover). The optimized sampling strategy could provide good precision in the richness estimation of macrobenthos and balance the sampling effort. Moreover, the conclusions presented here provide a reference for recommendations to consider before macrobenthic surveys take place in estuarine wetlands. The sampling strategy, focusing on the three key parts of the sampling design, had a good operational effect and could be used as a guide for field sampling for habitat management or ecosystem assessment.
文摘Shape-induced phase transition of vortex domain structures(VDSs)in BaTiO_3(BT)nanodots under open circuit boundary condition have been investigated using an effective Hamiltonian method.Our calculation indicates the tetragonal VDS missing in cubic BT nanodots can be induced by varying the shape of a nanodot from cube to platelet.Interestingly,a novel VDS is found in BT nanoplatelets in our simulations.Further investigation shows that it is a result of compromise between the ground state and the symmetry of the shape of the nanodot.Furthermore,based on the novel VDS,routes of controlling VDSs governed by homogeneous electric field and uniform stress are discussed.In particular,our results show the possibility of designing multi-states devices based on a single VDS.
基金supported in part by the National Key R&D Program of China(2019YFB1406504)the National Natural Science Foundation of China(U1836108,U1936216,62002197).
文摘Reversible data hiding in encrypted image(RDHEI)is a widely used technique for privacy protection,which has been developed in many applications that require high confidentiality,authentication and integrity.Proposed RDHEI methods do not allow high embedding rate while ensuring losslessly recover the original image.Moreover,the ciphertext form of encrypted image in RDHEI framework is easy to cause the attention of attackers.This paper proposes a reversible data hiding algorithm based on image camouflage encryption and bit plane compression.A camouflage encryption algorithm is used to transform a secret image into another meaningful target image,which can cover both secret image and encryption behavior based on“plaintext to plaintext”transformation.An edge optimization method based on prediction algorithm is designed to improve the image camouflage encryption quality.The reversible data hiding based bit-plane level compression,which can improve the redundancy of the bit plane by Gray coding,is used to embed watermark in the camouflage image.The experimental results also show the superior performance of the method in terms of embedding capacity and image quality.
基金supported by the National Natural Science Foundation of China (Grant Number:61875160).
文摘Objective and Impact Statement.Distinguishing malignant lymphocytes from normal ones is vital in pathological examination.We proposed an inverse light scattering(ILS)method for label-free suspended lymphocytes with complex fine structures to identify their volumes for pathological state.Introduction.Light scattering as cell’s“fingerprint”provides valuable morphology information closely related to its biophysical states.However,the detail relationships between the morphology with complex fine structures and its scattering characters are not fully understood.Methods.To quantitatively inverse the volumes of membrane and nucleus as the main scatterers,clinical lymphocyte morphologies were modeled combining the Gaussian random sphere geometry algorithm by 750 reconstructed results after confocal scanning,which allowed the accurate simulation to solve ILS problem.For complex fine structures,the specificity for ILS study was firstly discussed(to our knowledge)considering the differences of not only surface roughness,posture,but also the ratio of nucleus to the cytoplasm and refractive index.Results.The volumes of membrane and nucleus were proved theoretically to have good linear relationship with the effective area and entropy of forward scattering images.Their specificity deviations were less than 3.5%.Then,our experimental results for microsphere and clinical leukocytes showed the Pearson product-moment correlation coefficients(PPMCC)of this linear relationship were up to 0.9830~0.9926.Conclusion.Our scattering inversion method could be effectively applied to identify suspended label-free lymphocytes without destructive sample pretreatments and complex experimental systems.
基金The authors gratefully acknowledge the support from the National Natural Science Foundation of China(No.51474181)and Open Fund(PLN1516)of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University).
文摘Slow strain rate test(SSRT)and tensile fracture observation are applied to study the stress corrosion cracking(SCC)of L360NS pipeline steel.5.0 wt.%sodium chloride solution containing elemental sulfur and 0.5 wt.%glacial acetic acid solution containing elemental sulfur are used.The results show that brittle fracture mainly occurs on the samples in high sulfur environment.In the sulfur suspension solution,the SCC sensitivity of L360NS pipeline steel increases along elemental sulfur content.In sulfur melting cladding condition,obvious corrosion can be observed with a large amount of corrosion pits appearing on the gauge section of the sample.The corrosion products are Fe1txS,black easily detached,and H2.In sulfur suspension and sulfur melting cladding conditions,stress oriented hydrogen induced cracking(SOHIC)is the main cracking,which is caused by the joint effect of SCC and hydrogen induced cracking(HIC).
基金This work was supported by the National Natural Science Foundation of China(Grant nos.11972382,12002400,12132020,11832019)the Guangzhou Science and Technology Project(Grant no.2019060001).
文摘Mechanical control of ferroelectric domain evolution has attracted much interest over the past decade.Nevertheless,bidirectional 180°mechanical switching,i.e.,a complete cycle of mechanical writing and then erasing of a ferroelectric nanodomain,has not yet been realized in tip-film architectures.Here,via first-principles-based molecular dynamics simulations,we demonstrate that bidirectional 180°mechanical switching is possible in tip-film architectures when screening condition of ferroelectric films and tip loading force are within an appropriate window.The switching utilizes a delicate competition between the flexoelectric field and an overlooked effective dipolar field.The effective dipolar field dominates at small tip force and trigger switching from a downward single-domain state to an upward poly-domain state,whereas the flexoelectric field dominates at relatively large tip force and enables a back-switching.Bidirectional mechanical switching is achieved by applying tip force pulses with alternatively varying strength.The dipole-dipole interaction dynamics play important roles in mechanical switching.
基金This work was supported by the National Key Basic Research Program of China(Nos.2015CB351905)NSFC(Nos.11474363,51172291,11602310)the Guangzhou Science and Technology Project(No.201707020002).
文摘The toroidal order of electric dipoles in ferroelectric materials has attracted attention in the past decade due to fascinating properties and great potential for enabling novel memory devices,and functional devices in general.However,facile manipulation of toroidal order in ferroelectrics remains challenging.Here,using first-principles derived simulations,we demonstrate an efficient scheme to control the polar-toroidal multi-order(PTMO)states in ferroelectric nanowires.Two feasible strategies of controlling PTMO states by a combination of homogeneous electric field and torque are carried out in ferroelectric/paraelectric composite nanowires.This is possible based on trilinear coupling between polarization,toroidization and the twist force.As a result,switching of the toroidization of the nanowire can be readily achieved by reversal of the axial polarization.The torque threshold needed to control PTMO states is also calculated and found to be relatively small,indicating the feasibility of this method.Our study demonstrates facile control of PTMO states,including ferroelectric skyrmions,in ferroelectrics and is a step towards designing ferroelectric devices based on multi-order states.
