Histamine in food has attracted widespread attention due to the potential toxicity and associated health risk.However,its influences on immunological components,especially the function of key immune cells,are still po...Histamine in food has attracted widespread attention due to the potential toxicity and associated health risk.However,its influences on immunological components,especially the function of key immune cells,are still poorly known.In this work,we explored the effects of exogenous histamine on the function of key immune cells such as intestinal epithelial cells,dendritic cells,and T cells.The results showed that histamine could affect the expression of allergy-related genes in CMT93 cells at a high dose of histamine.Moreover,it’s found that histamine could cause an imbalance in the levels of relevant immune factors secreted by dendritic cells and T cells,especially those related to allergy.At the same time,the proportion of MHC class IIpositive dendritic cells and the proportion of T helper 2(Th2)cells in CD4^(+)T cells increased after histamine stimulation.We concluded that the presence of a certain level of histamine in food may affect the expression of allergy-related cytokines,disrupt the balance of the immune homeostasis,and potentially lead to adverse immune reactions.This work demonstrated the importance of including the estimation of histamine’s immune safety in aquatic products rather than merely considering the potential risk of food poisoning.展开更多
Semantic segmentation of remote sensing images is one of the core tasks of remote sensing image interpretation.With the continuous develop-ment of artificial intelligence technology,the use of deep learning methods fo...Semantic segmentation of remote sensing images is one of the core tasks of remote sensing image interpretation.With the continuous develop-ment of artificial intelligence technology,the use of deep learning methods for interpreting remote-sensing images has matured.Existing neural networks disregard the spatial relationship between two targets in remote sensing images.Semantic segmentation models that combine convolutional neural networks(CNNs)and graph convolutional neural networks(GCNs)cause a lack of feature boundaries,which leads to the unsatisfactory segmentation of various target feature boundaries.In this paper,we propose a new semantic segmentation model for remote sensing images(called DGCN hereinafter),which combines deep semantic segmentation networks(DSSN)and GCNs.In the GCN module,a loss function for boundary information is employed to optimize the learning of spatial relationship features between the target features and their relationships.A hierarchical fusion method is utilized for feature fusion and classification to optimize the spatial relationship informa-tion in the original feature information.Extensive experiments on ISPRS 2D and DeepGlobe semantic segmentation datasets show that compared with the existing semantic segmentation models of remote sensing images,the DGCN significantly optimizes the segmentation effect of feature boundaries,effectively reduces the noise in the segmentation results and improves the segmentation accuracy,which demonstrates the advancements of our model.展开更多
Upper Circumpolar Deep Water(UCDW)and North Pacifi c Deep Water(NPDW)coexist in the upper deep layer(i.e.,with a 1.2-2.0-℃potential temperature range and a 2000-4100-dbar pressure range)of the Eastern Philippine Sea....Upper Circumpolar Deep Water(UCDW)and North Pacifi c Deep Water(NPDW)coexist in the upper deep layer(i.e.,with a 1.2-2.0-℃potential temperature range and a 2000-4100-dbar pressure range)of the Eastern Philippine Sea.They have similar properties in potential temperature and salinity,while have a signifi cant diff erence in dissolved silicate.Based on the repeated observations along a 137°E transect from the World Ocean Database(WOD18),this study revealed the interannual variability of dissolved silicate in the upper deep layer of the Eastern Philippine Sea.Dissolved silicate increased in 1995,1996,2005,2006,and 2007,and decreased in 1997,2000,2001,2002,and 2004.Composition analysis showed that the large diff erence between positive and negative dissolved silicate anomalies occurred mainly at~15°N and north of 25°N,with the concentration reaching 4.25μmol/g.Further analysis indicated that the interannual dissolved silicate variability was related to the zonal current variation in the upper deep layer.The relatively strong(weak)westward current transport increased(decreased)NPDW to the Eastern Philippine Sea,thereby resulting in increased(decreased)dissolved silicate.展开更多
To address the problem of conventional approaches for mechanical property determination requiring destructive sampling, which may be unsuitable for in-service structures, the authors proposed a method for determining ...To address the problem of conventional approaches for mechanical property determination requiring destructive sampling, which may be unsuitable for in-service structures, the authors proposed a method for determining the quasi-static fracture toughness and impact absorbed energy of ductile metals from spherical indentation tests (SITs). The stress status and damage mechanism of SIT, mode I fracture, Charpy impact tests, and related tests were frst investigated through fnite element (FE) calculations and scanning electron microscopy (SEM) observations, respectively. It was found that the damage mechanism of SITs is diferent from that of mode I fractures, while mode I fractures and Charpy impact tests share the same damage mechanism. Considering the diference between SIT and mode I fractures, uniaxial tension and pure shear were introduced to correlate SIT with mode I fractures. Based on this, the widely used critical indentation energy (CIE) model for fracture toughness determination using SITs was modifed. The quasi-static fracture toughness determined from the modifed CIE model was used to evaluate the impact absorbed energy using the dynamic fracture toughness and energy for crack initiation. The efectiveness of the newly proposed method was verifed through experiments on four types of steels: Q345R, SA508-3, 18MnMoNbR, and S30408.展开更多
Based on the high-resolution Eulerian fields of an ocean general circulation model simulation, the heat contribution of the Indonesian throughflow(ITF) to the Indian Ocean is estimated by Lagrangian tracing method.The...Based on the high-resolution Eulerian fields of an ocean general circulation model simulation, the heat contribution of the Indonesian throughflow(ITF) to the Indian Ocean is estimated by Lagrangian tracing method.The heat transport of each particle of ITF waters is calculated by tracing temperature change along the trajectory until the particle exits the Indian Ocean. The simulation reveals that the ITF waters flow westward and branch near Madagascar, further showing the ITF waters are redistributed in both northern and southern Indian Ocean.Heat budget analysis indicates that the ITF waters gain 0.41 PW(Petawatts, 1015 W) in the northern Indian Ocean and lose 0.56 PW in the southern Indian Ocean, respectively. As a result, the ITF waters warm the whole Indian Ocean basin with only 0.15 PW, which shows an "insignificant" role of ITF on the Indian Ocean because of the heat exchange compensation between northern and southern Indian Ocean. Furthermore, the tracing pathways show that the ITF waters mainly flow out the Indian Ocean at both sides of the basin via Agulhas Current and Leeuwin Current. About 89% of the ITF waters leave along western boundary and the rest 11% along eastern boundary. Compared to seeding section, 0.10 PW and 0.05 PW are released to the Indian Ocean, respectively.展开更多
Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its ad...Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its adjacent area,the eastern Leizhou Peninsula upwelling(ELPU)were illustrated.It is found that a significant cold tongue with high salinity and low temperature along the eastern Hainan coast driven by upwelling-favorable summer monsoon.The ELPU was relative weaker than the EHU because of its wide and gentle continental slope.Due to mixing by tides and waves,DO concentration with high value(>6.0 mg/L)were almost homogenous from surface to 30 m depth at the EHU.Beneath that,low DO water(<6.0 mg/L,anoxia)were pumped upward from bottom by the upwelling.The ELPU has worse DO condition compared with the EHU where bottom DO were lower than 3.5 mg/L owing to abundant DO consumption.The phytoplankton biomass reached maximal value about 1.5 mg/m3 at 30 m depth layer rather than surface layer at the EHU indicating the impact limit of upwelling on phytoplankton growth and DO distribution.Nourished by rich nutrient input,the phytoplankton biomass at the ELPU were much higher than the EHU where the maximal value can reach about 4.0 mg/m3.The phytoplankton biomass were reduced to about 0.2–0.3 mg/m3 at the offshore areas of the EHU and ELPU which were close to the value at open sea.At the inshore of the EHU,the phytoplankton community was dominated by diatom which accounted for about 50%of phytoplankton biomass.And prokaryotes(about 40%),green algae(about 20%)and prochlorococcus(about 20%)became main species at the offshore of the EHU.At the ELPU,diatom accounted for about 80%of phytoplankton biomass followed by green algae,indicating a different ecosystem at this region compared with the EHU.展开更多
Fluororesin-based anti-corrosive coatings including graded FEP/PPS were prepared on carbon steel by melt powder coating, the bonding strength of all coating systems was determined by the pull-off test. It is found tha...Fluororesin-based anti-corrosive coatings including graded FEP/PPS were prepared on carbon steel by melt powder coating, the bonding strength of all coating systems was determined by the pull-off test. It is found that the poor adhesion of fluororesin coatings to metallic substrates is improved obviously by the graded coating structure of FEP/PPS, and the bonding strength reaches up to 11.8 MPa for the five-layer system. Examination by electron probe microanalysis (EPMA) verifies that the distribution of main components is graded in the five-layer system, which is responsible for the enhancement of the interfacial bonding.展开更多
Ocean salinity is an essential measurable indicator of water cycle and plays a crucial role in regulating ocean and climate change.Using Simple Ocean Data Assimilation(SODA)reanalysis product,substantial decadal varia...Ocean salinity is an essential measurable indicator of water cycle and plays a crucial role in regulating ocean and climate change.Using Simple Ocean Data Assimilation(SODA)reanalysis product,substantial decadal variability of the salinity in the upper layer of the South China Sea(SCS)from 1960 to 2010 was examined.Results show that a decadal variation of the upper layer salinity is clear.The upper layer(100 m)waters are found to freshen from 1960,become saltier during 1975 to 1995,and freshen again from 1995 to 2010.The strongest anomalies appear in the northeastern,northern,and northwestern regions in the three periods,respectively.The salinity variation trends become weaker below the upper layer,except the salinifi cation trend in the northern SCS extends to at least 300 m during the salinifi cation period.Diagnosis of the salinity budget over the top 100 m shows that during the fi rst freshening period horizontal advection,vertical advection,and surface freshwater forcing all contribute to salinity freshening,and horizontal advection is relatively larger.The contribution of horizontal advection and surface freshwater forcing to the positive salinity anomaly is comparable,while the vertical advection is the secondary factor in the salinifi cation period.Horizontal advection,especially zonal advection,plays a crucial role during the second freshening period.Moreover,horizontal advection is more important than that in the fi rst freshening period.In addition,the contribution of horizontal advection is mainly in zonal direction controlled by Kuroshio intrusion.Further analysis shows the upper-layer salinity variations have a Pacifi c Decadal Oscillation(PDO)-like signal,with freshening during the negative PDO years,and salinifi cation during the positive PDO years.PDO mainly infl uences the upper-layer salinity changes through both atmospheric bridge and oceanic bridge.展开更多
Based on first-principles calculations, Boltzmann transport equation and semiclassical analysis, we conduct a detailed study on the lattice thermal conductivity κL, Seebeck coefficient S, electrical conductivity σ, ...Based on first-principles calculations, Boltzmann transport equation and semiclassical analysis, we conduct a detailed study on the lattice thermal conductivity κL, Seebeck coefficient S, electrical conductivity σ, power factor S2σ and dimensionless figure of merit, zT, for K3IO. It is found that K3IO exhibits relatively low lattice thermal conductivity of 0.93 W·m-1·K-1 at 300 K, which is lower than the value 1.26 W·m-1·K-1 of the classical TE material PbTe. This is due to the smaller phonon group velocity νg and smaller relaxation time τλ. The low lattice thermal conductivity can lead to excellent thermoelectric properties. Thus maximum zT of 2.87 is obtained at 700 K, and the zT = 0.41 at 300 K indicate that K3IO is a potential excellent room temperature TE material. Our research on K3IO shows that it has excellent thermoelectric properties, and it is a promising candidate for applications in fields in terms of thermoelectricity.展开更多
Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility.Currently,research on Fe-based materials mainly focuses on regulating...Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility.Currently,research on Fe-based materials mainly focuses on regulating the degradation rate.However,excessive release of Fe ions during material degrada-tion will induce the generation of reactive oxygen species(ROS),leading to oxidative stress and ferroptosis.Therefore,the con-trol of RoS release and the improvement of biocompatibility for Fe-based materials are very important.In this study,new Fe-Zn alloys were prepared by electrodeposition with the intention of using Zn as an antioxidant to reduce oxidative damage during alloy degradation.Initially,the impact of three potential degra-dation ions(Fe^(2+),Fe^(3+),Zn^(2+))from the Fe-Zn alloy on human endothelial cell(EC)activity and migration ability was investigated.Subsequently,cell adhesion,cell activity,ROs production and DNA damage were assessed at various locations surrounding the alloy.Finally,the influence of different concentrations of Zn^(2+) in the medium on cell viability and ROS production was evaluated.High levels of ROS exhibited evident toxic effects on ECs and promoted DNA damage.As an antioxidant,Zn?+effectively reduced ROS production around Fe and improved the cell viability on its surface at a concentration of 0.04 mmol/l.These findings demonstrate that Fe-Zn alloy can attenuate the ROS generated from Fe degradation therebyenhancingcytocompatibility.展开更多
Random bit generators are critical for information security,cryptography,stochastic modeling,and simulations.Speed and scalability are key challenges faced by current physical random bit generation.Herein,we propose a...Random bit generators are critical for information security,cryptography,stochastic modeling,and simulations.Speed and scalability are key challenges faced by current physical random bit generation.Herein,we propose a massively parallel scheme for ultrafast random bit generation towards rates of order 100 terabit per second based on a single micro-ring resonator.A modulation-instability-driven chaotic comb in a micro-ring resonator enables the simultaneous generation of hundreds of independent and unbiased random bit streams.A proof-of-concept experiment demonstrates that using our method,random bit streams beyond 2 terabit per second can be successfully generated with only 7 comb lines.This bit rate can be easily enhanced by further increasing the number of comb lines used.Our approach provides a chip-scale solution to random bit generation for secure communication and high-performance computation,and offers superhigh speed and large scalability.展开更多
A high-quality optical microcavity can enhance optical nonlinear effects by resonant recirculation,which provides a reliable platform for nonlinear optics research.When a soliton microcomb and a probe optical field ar...A high-quality optical microcavity can enhance optical nonlinear effects by resonant recirculation,which provides a reliable platform for nonlinear optics research.When a soliton microcomb and a probe optical field are coexisting in a micro-resonator,a concomitant microcomb(CMC)induced by cross-phase modulation(XPM)will be formed synchronously.Here,we characterize the CMC comprehensively in a micro-resonator through theory,numerical simulation,and experimental verification.It is found that the CMCs spectra are modulated due to resonant radiation(RR)resulting from the interaction of dispersion and XPM effects.The group velocity dispersion induces symmetric RRs on the CMC,which leads to a symmetric spectral envelope and a dual-peak pulse in frequency and temporal domains,respectively,while the group velocity mismatch breaks the symmetry of RRs and leads to asymmetric spectral and temporal profiles.When the group velocity is linearly varying with frequency,two RR frequencies are hyperbolically distributed about the pump,and the probe light acts as one of the asymptotic lines.Our results enrich the CMC dynamics and guide microcomb design and applications such as spectral extension and dark pulse generation.展开更多
Laser-based light detection and ranging(lidar)plays a significant role in both scientific and industrial areas.However,it is difficult for existing lidars to achieve high speed,high precision,and long distance simulta...Laser-based light detection and ranging(lidar)plays a significant role in both scientific and industrial areas.However,it is difficult for existing lidars to achieve high speed,high precision,and long distance simultaneously.Here,we demonstrate a high-performance lidar based on a chip-scaled soliton microcomb(SMC)that can realize all three specialties simultaneously.Aided by the excellent properties of ultrahigh repetition rate and the smooth envelope of the SMC,traditional optical frequency comb(OFC)-based dispersive interferometry is heavily improved and the measuring dead zone induced by the mismatch between the repetition rate of the OFC and resolution of the optical spectrum analyzer is totally eliminated.Combined with an auxiliary dual-frequency phase-modulated laser range finder,the none-dead-zone measurable range ambiguity is extended up to 1500 m.The proposed SMC lidar is experimentally implemented in both indoor and outdoor environment.In the outdoor baseline field,real-time,high-speed(up to 35 k Hz)measurement of a long distance of^1179 m is achieved with a minimum Allan deviation of 5.6μm at an average time of 0.2 ms(27 nm at an average time of 1.8 s after high-pass filtering).The present SMC lidar approaches a compact,fast,high-precision,and none-dead zone long-distance ranging system,aimed at emerging applications of frontier basic scientific research and advances in industrial manufacturing.展开更多
Optical frequency combs,a revolutionary light source characterized by discrete and equally spaced frequencies,are usually regarded as a cornerstone for advanced frequency metrology,precision spectroscopy,high-speed co...Optical frequency combs,a revolutionary light source characterized by discrete and equally spaced frequencies,are usually regarded as a cornerstone for advanced frequency metrology,precision spectroscopy,high-speed communication,distance ranging,molecule detection,and many others.Due to the rapid development of micro/nanofabrication technology,breakthroughs in the quality factor of microresonators enable ultrahigh energy buildup inside cavities,which gives birth to microcavity-based frequency combs.In particular,the full coherent spectrum of the soliton microcomb(SMC)provides a route to low-noise ultrashort pulses with a repetition rate over two orders of magnitude higher than that of traditional mode-locking approaches.This enables lower power consumption and cost for a wide range of applications.This review summarizes recent achievements in SMCs,including the basic theory and physical model,as well as experimental techniques for single-soliton generation and various extraordinary soliton states(soliton crystals,Stokes solitons,breathers,molecules,cavity solitons,and dark solitons),with a perspective on their potential applications and remaining challenges.展开更多
The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant mult...The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant multi-scale variability associated with the Indian Monsoon and the Indian Ocean dipole. This paper summarizes the research progress over recent years on the tropical Indian Ocean circulation system based on the large-scale hydrological observations and numerical simulations by the South China Sea Institute of Oceanology(SCSIO), Chinese Academy of Sciences. Results show that:(1) the wind-driven Kelvin and Rossby waves and eastern boundary-reflected Rossby waves regulate the formation and evolution of the Equatorial Undercurrent and the Equatorial Intermediate Current;(2) the equatorial wind-driven dynamics are the main factor controlling the inter-annual variability of the thermocline in the eastern Indian Ocean upwelling;(3) the equatorial waves transport large amounts of energy into the Bay of Bengal in forms of coastal Kelvin and reflected free Rossby waves. Several unresolved issues within the tropical Indian Ocean are discussed:(i) the potential effects of the momentum balance and the basin resonance on the variability of the equatorial circulation system, and(ii) the potential contribution of wind-driven dynamics to the life cycle of the eastern Indian Ocean upwelling. This paper also briefly introduces the international Indian Ocean investigation project of the SCSIO, which will advance the study of the multi-scale variability of the tropical Indian Ocean circulation system, and provide a theoretical and data basis to support marine environmental security for the countries around the Maritime Silk Road.展开更多
While deep learning has demonstrated tremendous potential for photonic device design,it often demands a large amount of labeled data to train these deep neural network models.Preparing these data requires high-resolut...While deep learning has demonstrated tremendous potential for photonic device design,it often demands a large amount of labeled data to train these deep neural network models.Preparing these data requires high-resolution numerical simulations or experimental measurements and cost significant,if not prohibitive,time and resources.In this work,we present a highly efficient inverse design method that combines deep neural networks with a genetic algorithm to optimize the geometry of photonic devices in the polar coordinate system.The method requires significantly less training data compared with previous inverse design methods.We implement this method to design several ultra-compact silicon photonics devices with challenging properties including power splitters with uncommon splitting ratios,a TE mode converter,and a broadband power splitter.These devices are free of the features beyond the capability of photolithography and generally in compliance with silicon photonics fabrication design rules.展开更多
We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is f...We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is found that parametric oscillation is inhibited in the telecom wavelength range resulting from strong two-photon absorption.On the contrary, beyond the wavelength of 2200 nm, where three-and four-photon absorption are less detrimental,a comb can be generated with moderate pump power, or free-carriers are swept out by a positive-intrinsic-negative structure. In the temporal domain, the generated combs correspond to flat-top pulses, and the pulse duration can be easily controlled by varying the laser detuning. The reported comb generation process shows a high conversion efficiency compared with anomalous dispersion regime, which can guide and promote comb formation in materials with normal dispersion. As the comb spectra cover the mid-infrared wavelength range, they can find applications in comb-based radiofrequency photonic filters and mid-infrared spectroscopy.展开更多
基金financially supported by the Key Project of Zhejiang Provincial Natural Science Foundation of China(LZ22C200003)the National Natural Science Foundation of China(32072290)。
文摘Histamine in food has attracted widespread attention due to the potential toxicity and associated health risk.However,its influences on immunological components,especially the function of key immune cells,are still poorly known.In this work,we explored the effects of exogenous histamine on the function of key immune cells such as intestinal epithelial cells,dendritic cells,and T cells.The results showed that histamine could affect the expression of allergy-related genes in CMT93 cells at a high dose of histamine.Moreover,it’s found that histamine could cause an imbalance in the levels of relevant immune factors secreted by dendritic cells and T cells,especially those related to allergy.At the same time,the proportion of MHC class IIpositive dendritic cells and the proportion of T helper 2(Th2)cells in CD4^(+)T cells increased after histamine stimulation.We concluded that the presence of a certain level of histamine in food may affect the expression of allergy-related cytokines,disrupt the balance of the immune homeostasis,and potentially lead to adverse immune reactions.This work demonstrated the importance of including the estimation of histamine’s immune safety in aquatic products rather than merely considering the potential risk of food poisoning.
基金funded by the Major Scientific and Technological Innovation Project of Shandong Province,Grant No.2022CXGC010609.
文摘Semantic segmentation of remote sensing images is one of the core tasks of remote sensing image interpretation.With the continuous develop-ment of artificial intelligence technology,the use of deep learning methods for interpreting remote-sensing images has matured.Existing neural networks disregard the spatial relationship between two targets in remote sensing images.Semantic segmentation models that combine convolutional neural networks(CNNs)and graph convolutional neural networks(GCNs)cause a lack of feature boundaries,which leads to the unsatisfactory segmentation of various target feature boundaries.In this paper,we propose a new semantic segmentation model for remote sensing images(called DGCN hereinafter),which combines deep semantic segmentation networks(DSSN)and GCNs.In the GCN module,a loss function for boundary information is employed to optimize the learning of spatial relationship features between the target features and their relationships.A hierarchical fusion method is utilized for feature fusion and classification to optimize the spatial relationship informa-tion in the original feature information.Extensive experiments on ISPRS 2D and DeepGlobe semantic segmentation datasets show that compared with the existing semantic segmentation models of remote sensing images,the DGCN significantly optimizes the segmentation effect of feature boundaries,effectively reduces the noise in the segmentation results and improves the segmentation accuracy,which demonstrates the advancements of our model.
基金Supported by the National Key Research and Development Program of China(No.2018YFC0309800)the National Natural Science Foundation of China(Nos.42176021,91858203)+1 种基金the Open Project Program of State Key Laboratory of Tropical Oceanography(No.LTOZZ2001)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0304)。
文摘Upper Circumpolar Deep Water(UCDW)and North Pacifi c Deep Water(NPDW)coexist in the upper deep layer(i.e.,with a 1.2-2.0-℃potential temperature range and a 2000-4100-dbar pressure range)of the Eastern Philippine Sea.They have similar properties in potential temperature and salinity,while have a signifi cant diff erence in dissolved silicate.Based on the repeated observations along a 137°E transect from the World Ocean Database(WOD18),this study revealed the interannual variability of dissolved silicate in the upper deep layer of the Eastern Philippine Sea.Dissolved silicate increased in 1995,1996,2005,2006,and 2007,and decreased in 1997,2000,2001,2002,and 2004.Composition analysis showed that the large diff erence between positive and negative dissolved silicate anomalies occurred mainly at~15°N and north of 25°N,with the concentration reaching 4.25μmol/g.Further analysis indicated that the interannual dissolved silicate variability was related to the zonal current variation in the upper deep layer.The relatively strong(weak)westward current transport increased(decreased)NPDW to the Eastern Philippine Sea,thereby resulting in increased(decreased)dissolved silicate.
基金Supported by National Natural Science Foundation of China(Grant No.52275154)National Key Research and Development Project of China(Grant No.2016YFF0203005).
文摘To address the problem of conventional approaches for mechanical property determination requiring destructive sampling, which may be unsuitable for in-service structures, the authors proposed a method for determining the quasi-static fracture toughness and impact absorbed energy of ductile metals from spherical indentation tests (SITs). The stress status and damage mechanism of SIT, mode I fracture, Charpy impact tests, and related tests were frst investigated through fnite element (FE) calculations and scanning electron microscopy (SEM) observations, respectively. It was found that the damage mechanism of SITs is diferent from that of mode I fractures, while mode I fractures and Charpy impact tests share the same damage mechanism. Considering the diference between SIT and mode I fractures, uniaxial tension and pure shear were introduced to correlate SIT with mode I fractures. Based on this, the widely used critical indentation energy (CIE) model for fracture toughness determination using SITs was modifed. The quasi-static fracture toughness determined from the modifed CIE model was used to evaluate the impact absorbed energy using the dynamic fracture toughness and energy for crack initiation. The efectiveness of the newly proposed method was verifed through experiments on four types of steels: Q345R, SA508-3, 18MnMoNbR, and S30408.
基金Strategic Priority Research Programs of the Chinese Academy of Sciences(XDA20060500)National Natural Science Foundation of China(41521005,41676013)+1 种基金National Key Research and Development Project(2016YFC1401401)Independent project of State Key Laboratory of Tropical Oceanography(LTOZZ1702)
基金The Strategic Priority Research Program of Chinese Academy of Sciences under contract Nos XDA20060502 and XDA11010301the National Key Research and Development Program of China under contract No.2016YFC1401401+2 种基金the National Natural Science Foundation of China under contract Nos 41676013,41521005 and 41731173the Independent Research Project Program of State Key Laboratory of Tropical Oceanography under contract No.LTOZZ1702the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Based on the high-resolution Eulerian fields of an ocean general circulation model simulation, the heat contribution of the Indonesian throughflow(ITF) to the Indian Ocean is estimated by Lagrangian tracing method.The heat transport of each particle of ITF waters is calculated by tracing temperature change along the trajectory until the particle exits the Indian Ocean. The simulation reveals that the ITF waters flow westward and branch near Madagascar, further showing the ITF waters are redistributed in both northern and southern Indian Ocean.Heat budget analysis indicates that the ITF waters gain 0.41 PW(Petawatts, 1015 W) in the northern Indian Ocean and lose 0.56 PW in the southern Indian Ocean, respectively. As a result, the ITF waters warm the whole Indian Ocean basin with only 0.15 PW, which shows an "insignificant" role of ITF on the Indian Ocean because of the heat exchange compensation between northern and southern Indian Ocean. Furthermore, the tracing pathways show that the ITF waters mainly flow out the Indian Ocean at both sides of the basin via Agulhas Current and Leeuwin Current. About 89% of the ITF waters leave along western boundary and the rest 11% along eastern boundary. Compared to seeding section, 0.10 PW and 0.05 PW are released to the Indian Ocean, respectively.
基金The National Key Research and Development Program of China under contract No.2018YFC0309800the National Natural Science Foundation of China under contract Nos 41666001,41576006,41976014,41776045+1 种基金the Chinese Academy of Sciences Frontier Basic Research Project under contract No.QYJC201910the Sanya Governmental Academy-Locality S&T Cooperation Program under contract No.2015YD28。
文摘Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its adjacent area,the eastern Leizhou Peninsula upwelling(ELPU)were illustrated.It is found that a significant cold tongue with high salinity and low temperature along the eastern Hainan coast driven by upwelling-favorable summer monsoon.The ELPU was relative weaker than the EHU because of its wide and gentle continental slope.Due to mixing by tides and waves,DO concentration with high value(>6.0 mg/L)were almost homogenous from surface to 30 m depth at the EHU.Beneath that,low DO water(<6.0 mg/L,anoxia)were pumped upward from bottom by the upwelling.The ELPU has worse DO condition compared with the EHU where bottom DO were lower than 3.5 mg/L owing to abundant DO consumption.The phytoplankton biomass reached maximal value about 1.5 mg/m3 at 30 m depth layer rather than surface layer at the EHU indicating the impact limit of upwelling on phytoplankton growth and DO distribution.Nourished by rich nutrient input,the phytoplankton biomass at the ELPU were much higher than the EHU where the maximal value can reach about 4.0 mg/m3.The phytoplankton biomass were reduced to about 0.2–0.3 mg/m3 at the offshore areas of the EHU and ELPU which were close to the value at open sea.At the inshore of the EHU,the phytoplankton community was dominated by diatom which accounted for about 50%of phytoplankton biomass.And prokaryotes(about 40%),green algae(about 20%)and prochlorococcus(about 20%)became main species at the offshore of the EHU.At the ELPU,diatom accounted for about 80%of phytoplankton biomass followed by green algae,indicating a different ecosystem at this region compared with the EHU.
文摘Fluororesin-based anti-corrosive coatings including graded FEP/PPS were prepared on carbon steel by melt powder coating, the bonding strength of all coating systems was determined by the pull-off test. It is found that the poor adhesion of fluororesin coatings to metallic substrates is improved obviously by the graded coating structure of FEP/PPS, and the bonding strength reaches up to 11.8 MPa for the five-layer system. Examination by electron probe microanalysis (EPMA) verifies that the distribution of main components is graded in the five-layer system, which is responsible for the enhancement of the interfacial bonding.
基金Supported by the National Natural Science Foundation of China(Nos.91958202,41731173)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA20060502)+1 种基金the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0306)the Key Research Program of the Chinese Academy of Sciences(No.ZDRWXH-2019-2)。
文摘Ocean salinity is an essential measurable indicator of water cycle and plays a crucial role in regulating ocean and climate change.Using Simple Ocean Data Assimilation(SODA)reanalysis product,substantial decadal variability of the salinity in the upper layer of the South China Sea(SCS)from 1960 to 2010 was examined.Results show that a decadal variation of the upper layer salinity is clear.The upper layer(100 m)waters are found to freshen from 1960,become saltier during 1975 to 1995,and freshen again from 1995 to 2010.The strongest anomalies appear in the northeastern,northern,and northwestern regions in the three periods,respectively.The salinity variation trends become weaker below the upper layer,except the salinifi cation trend in the northern SCS extends to at least 300 m during the salinifi cation period.Diagnosis of the salinity budget over the top 100 m shows that during the fi rst freshening period horizontal advection,vertical advection,and surface freshwater forcing all contribute to salinity freshening,and horizontal advection is relatively larger.The contribution of horizontal advection and surface freshwater forcing to the positive salinity anomaly is comparable,while the vertical advection is the secondary factor in the salinifi cation period.Horizontal advection,especially zonal advection,plays a crucial role during the second freshening period.Moreover,horizontal advection is more important than that in the fi rst freshening period.In addition,the contribution of horizontal advection is mainly in zonal direction controlled by Kuroshio intrusion.Further analysis shows the upper-layer salinity variations have a Pacifi c Decadal Oscillation(PDO)-like signal,with freshening during the negative PDO years,and salinifi cation during the positive PDO years.PDO mainly infl uences the upper-layer salinity changes through both atmospheric bridge and oceanic bridge.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11974302,11774396,and 11704322)the Shandong Natural Science Funds for Doctoral Program,China(Grant No.ZR2017BA017).
文摘Based on first-principles calculations, Boltzmann transport equation and semiclassical analysis, we conduct a detailed study on the lattice thermal conductivity κL, Seebeck coefficient S, electrical conductivity σ, power factor S2σ and dimensionless figure of merit, zT, for K3IO. It is found that K3IO exhibits relatively low lattice thermal conductivity of 0.93 W·m-1·K-1 at 300 K, which is lower than the value 1.26 W·m-1·K-1 of the classical TE material PbTe. This is due to the smaller phonon group velocity νg and smaller relaxation time τλ. The low lattice thermal conductivity can lead to excellent thermoelectric properties. Thus maximum zT of 2.87 is obtained at 700 K, and the zT = 0.41 at 300 K indicate that K3IO is a potential excellent room temperature TE material. Our research on K3IO shows that it has excellent thermoelectric properties, and it is a promising candidate for applications in fields in terms of thermoelectricity.
基金supported by the National Key Research and Development Program of China[grant number 2016YFC1401803]the National Natural Science Foundation of China[grant numbers 41976019 and 42076020]+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA20060502]the open project of the State Key Laboratory of Tropical Oceanography,South China Sea Institute of Oceanology,Chinese Academy of Sciences[grant number LTO1910]the Research Program of the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)[grant number GML2019ZD0306]the Key Research Program of the Chinese Academy of Sciences[grant number ZDRW-XH-2019-2]。
基金supported by“the Fundamental Research Funds for the Central Universities”of China(DUT23YG229,DUT22YG118)SEM and EPMA data were obtained using equipment(IT800-SHL,JXA-8530F PLUS)maintained by the School of Materials Science and Engineering,Dalian University of Technology.
文摘Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility.Currently,research on Fe-based materials mainly focuses on regulating the degradation rate.However,excessive release of Fe ions during material degrada-tion will induce the generation of reactive oxygen species(ROS),leading to oxidative stress and ferroptosis.Therefore,the con-trol of RoS release and the improvement of biocompatibility for Fe-based materials are very important.In this study,new Fe-Zn alloys were prepared by electrodeposition with the intention of using Zn as an antioxidant to reduce oxidative damage during alloy degradation.Initially,the impact of three potential degra-dation ions(Fe^(2+),Fe^(3+),Zn^(2+))from the Fe-Zn alloy on human endothelial cell(EC)activity and migration ability was investigated.Subsequently,cell adhesion,cell activity,ROs production and DNA damage were assessed at various locations surrounding the alloy.Finally,the influence of different concentrations of Zn^(2+) in the medium on cell viability and ROS production was evaluated.High levels of ROS exhibited evident toxic effects on ECs and promoted DNA damage.As an antioxidant,Zn?+effectively reduced ROS production around Fe and improved the cell viability on its surface at a concentration of 0.04 mmol/l.These findings demonstrate that Fe-Zn alloy can attenuate the ROS generated from Fe degradation therebyenhancingcytocompatibility.
基金National Natural Science Foundation of China(61927811,62175177,62322504,62075238,and U19A2076)Innovation Program for Quantum Science and Technology(2021ZD0300701,2021ZD0301500)+1 种基金Program for Guangdong Introducing Innovative and Entrepreneurial TeamsStability Program of Science and Technology on Communication Security Laboratory(2022).
文摘Random bit generators are critical for information security,cryptography,stochastic modeling,and simulations.Speed and scalability are key challenges faced by current physical random bit generation.Herein,we propose a massively parallel scheme for ultrafast random bit generation towards rates of order 100 terabit per second based on a single micro-ring resonator.A modulation-instability-driven chaotic comb in a micro-ring resonator enables the simultaneous generation of hundreds of independent and unbiased random bit streams.A proof-of-concept experiment demonstrates that using our method,random bit streams beyond 2 terabit per second can be successfully generated with only 7 comb lines.This bit rate can be easily enhanced by further increasing the number of comb lines used.Our approach provides a chip-scale solution to random bit generation for secure communication and high-performance computation,and offers superhigh speed and large scalability.
基金National Key Research and Development Program of China(2021YFB2800603)National Natural Science Foundation of China(62075238)+1 种基金Foundation of Science and Technology on Metrology and Calibration Laboratory(JLJK2021001A004)West Light Foundation of the Chinese Academy of Sciences(E0291113)。
文摘A high-quality optical microcavity can enhance optical nonlinear effects by resonant recirculation,which provides a reliable platform for nonlinear optics research.When a soliton microcomb and a probe optical field are coexisting in a micro-resonator,a concomitant microcomb(CMC)induced by cross-phase modulation(XPM)will be formed synchronously.Here,we characterize the CMC comprehensively in a micro-resonator through theory,numerical simulation,and experimental verification.It is found that the CMCs spectra are modulated due to resonant radiation(RR)resulting from the interaction of dispersion and XPM effects.The group velocity dispersion induces symmetric RRs on the CMC,which leads to a symmetric spectral envelope and a dual-peak pulse in frequency and temporal domains,respectively,while the group velocity mismatch breaks the symmetry of RRs and leads to asymmetric spectral and temporal profiles.When the group velocity is linearly varying with frequency,two RR frequencies are hyperbolically distributed about the pump,and the probe light acts as one of the asymptotic lines.Our results enrich the CMC dynamics and guide microcomb design and applications such as spectral extension and dark pulse generation.
基金Key Projects Supported by Science and Technology of Tianjin(18YFZCGX00920)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2016353)+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB24030600)National Key Research and Development Program of China(2018YFB2003501,2018YFF0212702)National Natural Science Foundation of China(51675380,51775379,61635013,61675231,61705257,61805277)。
文摘Laser-based light detection and ranging(lidar)plays a significant role in both scientific and industrial areas.However,it is difficult for existing lidars to achieve high speed,high precision,and long distance simultaneously.Here,we demonstrate a high-performance lidar based on a chip-scaled soliton microcomb(SMC)that can realize all three specialties simultaneously.Aided by the excellent properties of ultrahigh repetition rate and the smooth envelope of the SMC,traditional optical frequency comb(OFC)-based dispersive interferometry is heavily improved and the measuring dead zone induced by the mismatch between the repetition rate of the OFC and resolution of the optical spectrum analyzer is totally eliminated.Combined with an auxiliary dual-frequency phase-modulated laser range finder,the none-dead-zone measurable range ambiguity is extended up to 1500 m.The proposed SMC lidar is experimentally implemented in both indoor and outdoor environment.In the outdoor baseline field,real-time,high-speed(up to 35 k Hz)measurement of a long distance of^1179 m is achieved with a minimum Allan deviation of 5.6μm at an average time of 0.2 ms(27 nm at an average time of 1.8 s after high-pass filtering).The present SMC lidar approaches a compact,fast,high-precision,and none-dead zone long-distance ranging system,aimed at emerging applications of frontier basic scientific research and advances in industrial manufacturing.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61635013 and 61675231)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB24030600)the Youth Innovation Promotion Association of CAS(Grant No.2016353)。
文摘Optical frequency combs,a revolutionary light source characterized by discrete and equally spaced frequencies,are usually regarded as a cornerstone for advanced frequency metrology,precision spectroscopy,high-speed communication,distance ranging,molecule detection,and many others.Due to the rapid development of micro/nanofabrication technology,breakthroughs in the quality factor of microresonators enable ultrahigh energy buildup inside cavities,which gives birth to microcavity-based frequency combs.In particular,the full coherent spectrum of the soliton microcomb(SMC)provides a route to low-noise ultrashort pulses with a repetition rate over two orders of magnitude higher than that of traditional mode-locking approaches.This enables lower power consumption and cost for a wide range of applications.This review summarizes recent achievements in SMCs,including the basic theory and physical model,as well as experimental techniques for single-soliton generation and various extraordinary soliton states(soliton crystals,Stokes solitons,breathers,molecules,cavity solitons,and dark solitons),with a perspective on their potential applications and remaining challenges.
基金supported by the National Key Research and Development Program of China(Grant No.2017YFC1405100)the National Natural Science Foundation of China(Grant Nos.41521005,41476011,41706027,41676013)+4 种基金the Natural Science Foundation of Guangdong(Grant No.2016A030310015)the Open Fund of the Key Laboratory of Ocean Circulation and Waves,Chinese Academy of Sciences(Grant No.KLOCW1604)the Open Fund of the State Key Laboratory of Tropical Oceanography(Grant No.LTOZZ1702)the MEL Visiting Fellowship(Grant No.MELRS1640)the Guangzhou Science and Technology Foundation(Grant No.201804010133)
文摘The tropical Indian Ocean circulation system includes the equatorial and near-equatorial circulations, the marginal sea circulation, and eddies. The dynamic processes of these circulation systems show significant multi-scale variability associated with the Indian Monsoon and the Indian Ocean dipole. This paper summarizes the research progress over recent years on the tropical Indian Ocean circulation system based on the large-scale hydrological observations and numerical simulations by the South China Sea Institute of Oceanology(SCSIO), Chinese Academy of Sciences. Results show that:(1) the wind-driven Kelvin and Rossby waves and eastern boundary-reflected Rossby waves regulate the formation and evolution of the Equatorial Undercurrent and the Equatorial Intermediate Current;(2) the equatorial wind-driven dynamics are the main factor controlling the inter-annual variability of the thermocline in the eastern Indian Ocean upwelling;(3) the equatorial waves transport large amounts of energy into the Bay of Bengal in forms of coastal Kelvin and reflected free Rossby waves. Several unresolved issues within the tropical Indian Ocean are discussed:(i) the potential effects of the momentum balance and the basin resonance on the variability of the equatorial circulation system, and(ii) the potential contribution of wind-driven dynamics to the life cycle of the eastern Indian Ocean upwelling. This paper also briefly introduces the international Indian Ocean investigation project of the SCSIO, which will advance the study of the multi-scale variability of the tropical Indian Ocean circulation system, and provide a theoretical and data basis to support marine environmental security for the countries around the Maritime Silk Road.
基金the Chinese Academy of Sciences(XDB24030600)National Natural Science Foundation of China(12004421,61635013,61675231)+3 种基金Youth Innovation Promotion Association of Chinese Academy of Sciences(2016535)West Light Foundation of the Chinese Academy of Sciences(XAB2017A09)Natural Science Basic Research Program of Shaanxi(2019JQ-447)Research Project of Xi’an Postdoctoral Innovation Base(201903).
文摘While deep learning has demonstrated tremendous potential for photonic device design,it often demands a large amount of labeled data to train these deep neural network models.Preparing these data requires high-resolution numerical simulations or experimental measurements and cost significant,if not prohibitive,time and resources.In this work,we present a highly efficient inverse design method that combines deep neural networks with a genetic algorithm to optimize the geometry of photonic devices in the polar coordinate system.The method requires significantly less training data compared with previous inverse design methods.We implement this method to design several ultra-compact silicon photonics devices with challenging properties including power splitters with uncommon splitting ratios,a TE mode converter,and a broadband power splitter.These devices are free of the features beyond the capability of photolithography and generally in compliance with silicon photonics fabrication design rules.
基金National Natural Science Foundation of China(NSFC)(61635013,61675231,61475188,61705257)Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB24030600)
文摘We investigate frequency-comb generation in normal dispersion silicon microresonators from the near-infrared to mid-infrared wavelength range in the presence of multiphoton absorption and free-carrier effects. It is found that parametric oscillation is inhibited in the telecom wavelength range resulting from strong two-photon absorption.On the contrary, beyond the wavelength of 2200 nm, where three-and four-photon absorption are less detrimental,a comb can be generated with moderate pump power, or free-carriers are swept out by a positive-intrinsic-negative structure. In the temporal domain, the generated combs correspond to flat-top pulses, and the pulse duration can be easily controlled by varying the laser detuning. The reported comb generation process shows a high conversion efficiency compared with anomalous dispersion regime, which can guide and promote comb formation in materials with normal dispersion. As the comb spectra cover the mid-infrared wavelength range, they can find applications in comb-based radiofrequency photonic filters and mid-infrared spectroscopy.