Channel dredging in estuaries increases water depth and subsequently impacts sediment dynamics and morphology. The Jiaojiang River Estuary is dredged frequently owing to heavy shipping demands. In this study,the effec...Channel dredging in estuaries increases water depth and subsequently impacts sediment dynamics and morphology. The Jiaojiang River Estuary is dredged frequently owing to heavy shipping demands. In this study,the effects of different dredging schemes on siltation were assessed through numerical modeling. The sediment model of the Jiaojiang River Estuary utilized an optimized bottom boundary layer model that considered the bed sediment grain size and fluid mud, and this model was calibrated using field data. Result reveal that channel dredging modifies the flow velocity inside and around the channel by changing the bathymetry;subsequently, this affects the residual current, bed stress, suspended sediment concentration, and sediment fluxes. Increasing the dredging depth and width increases the net sediment fluxes into the channel and dredging depth has a greater influence on the channel siltation thickness. When the dredging depth is 8.4 m or11.4 m, the average siltation thickness of the channel is 0.07 m or 0.15 m per mouth respectively. The parallel movement of the channel has small effects on the siltation volume during the simulation period. The sediment deposits in the channel primarily originates from the tidal flats, through bottom sediment fluxes. Vertical net circulation has a dominant impact on siltation because the difference of horizontal current of each layer on the longitudinal section of the channel increases, which intensifies the lateral sediment transport between the shoal and channel. The influence of vertical frictional dissipation on the lateral circulation at the feature points accounts for more than 50% before dredging, while the non-linear advective term is dominant after dredging. Tidal pumping mainly affects the longitudinal sediment fluxes in the channel. These results can be used for channel management and planning for similar estuaries worldwide.展开更多
We propose a novel approach called the robust fractional-order proportional-integral-derivative（FOPID）controller, to stabilize a perturbed nonlinear chaotic system on one of its unstable fixed points. The stability ...We propose a novel approach called the robust fractional-order proportional-integral-derivative（FOPID）controller, to stabilize a perturbed nonlinear chaotic system on one of its unstable fixed points. The stability analysis of the nonlinear chaotic system is made based on the proportional-integral-derivative actions using the bifurcation diagram. We extract an initial set of controller parameters, which are subsequently optimized using a quadratic criterion. The integral and derivative fractional orders are also identified by this quadratic criterion. By applying numerical simulations on two nonlinear systems, namely the multi-scroll Chen system and the Genesio-Tesi system,we show that the fractional PI~λD~μ controller provides the best closed-loop system performance in stabilizing the unstable fixed points, even in the presence of random perturbation.展开更多
为探究呈岛屿间断分布的中国特有种油叶柯〔Lithocarpus konishii(Hayata)Hayata〕的群落结构、区系特征及多样性,在其分布区广东担杆岛、香港及海南文昌设置13个典型样地(总面积5800 m 2)并开展群落学调查,分析其群落的物种组成、结构...为探究呈岛屿间断分布的中国特有种油叶柯〔Lithocarpus konishii(Hayata)Hayata〕的群落结构、区系特征及多样性,在其分布区广东担杆岛、香港及海南文昌设置13个典型样地(总面积5800 m 2)并开展群落学调查,分析其群落的物种组成、结构特征、区系特征、物种多样性及类型。结果表明:13个油叶柯样地物种组成丰富,共有维管植物200种(含种下等级,下同),隶属于74科162属,其中海南文昌样地的物种数(140种)远多于香港和广东担杆岛样地。从生活型看,13个油叶柯样地中乔木、灌木、草本和藤本分别有41、85、57和17种,占比分别为20.5%、42.5%、28.5%和8.5%。从地理成分看,13个油叶柯样地植物群落在科和属水平均以泛热带和热带亚洲分布为主,热带性质明显。多样性分析结果显示:油叶柯样地灌木层的物种多样性指数总体高于乔木层和草本层。基于乔木层重要值的聚类分析结果,13个油叶柯样地的植物群落划分为油叶柯+鹅掌柴林〔Form.L.konishii+Heptapleurum heptaphyllum(Linn.)Y.F.Deng〕、台湾相思+油叶柯林(Form.Acacia confusa Merr.+L.konishii)、油叶柯+文昌锥林(Form.L.konishii+Castanopsis wenchangensis G.A.Fu et C.C.Huang)3类,与地理分布相吻合。综上所述,油叶柯群落为具热带特性的常绿阔叶林,但因处于次生演替不稳定阶段,亟需制定针对性保护策略以维持生态系统稳态。展开更多
The effect of sodium reduction and Lactobacillus acidophilus addition(free or microencapsulated)on the quality parameters of requeijao cremoso processed cheese was assessed for 90 days at 5℃.Three formulations were p...The effect of sodium reduction and Lactobacillus acidophilus addition(free or microencapsulated)on the quality parameters of requeijao cremoso processed cheese was assessed for 90 days at 5℃.Three formulations were prepared:(CONT)regular salt content and curd fusion(90℃/2 min),(FREE)reduced salt content+free probiotic culture added after curd fusion(90℃/2 min),and(MICRO)reduced salt content+microencapsulated probiotic culture added before curd fusion(70℃/5 min).FREE and MICRO formulations showed increased monounsaturated and polyunsaturated fatty acid content,improved health indices(decreases in thrombogenic index and increases in desirable fatty acid index),and altered rheological properties(higher consistency index,apparent viscosity,elastic properties,and gel strength).In addition,the MICRO formulation showed higher texture sensory acceptance and probiotic counts higher than 6 log CFU/g during storage and simulated gastrointestinal conditions.Overall,microencapsulation of probiotics with spray chilling represents an innovative solution in requeijao cremoso processed cheese.展开更多
Age-related osteoporosis poses a significant challenge in musculoskeletal health;a condition characterized by reduced bone density and increased fracture susceptibility in older individuals necessitates a better under...Age-related osteoporosis poses a significant challenge in musculoskeletal health;a condition characterized by reduced bone density and increased fracture susceptibility in older individuals necessitates a better understanding of underlying molecular and cellular mechanisms.Emerging evidence suggests that osteocytes are the pivotal orchestrators of bone remodeling and represent novel therapeutic targets for age-related bone loss.Our study uses the prematurely aged PolgD257A/D257A(PolgA)mouse model to scrutinize age-and sex-related alterations in musculoskeletal health parameters(frailty,grip strength,gait data),bone and particularly the osteocyte lacuno-canalicular network(LCN).Moreover,a new quantitative in silico image analysis pipeline is used to evaluate the alterations in the osteocyte network with aging.Our findings underscore the pronounced degenerative changes in the musculoskeletal health parameters,bone,and osteocyte LCN in PolgA mice as early as 40 weeks,with more prominent alterations evident in aged males.Our findings suggest that the PolgA mouse model serves as a valuable model for studying the cellular mechanisms underlying age-related bone loss,given the comparable aging signs and age-related degeneration of the bone and the osteocyte network observed in naturally aging mice and elderly humans.展开更多
Non-stoichiometric carbides have been proven to be effective electromagnetic wave(EMW)absorbing materials.In this study,phase and morphology of XZnC(X=Fe/Co/Cu)loaded on a three dimensional(3D)network structure melami...Non-stoichiometric carbides have been proven to be effective electromagnetic wave(EMW)absorbing materials.In this study,phase and morphology of XZnC(X=Fe/Co/Cu)loaded on a three dimensional(3D)network structure melamine sponge(MS)carbon composites were investigated through vacuum filtration followed by calcination.The FeZnC/CoZnC/CuZnC with carbon nanotubes(CNTs)were uniformly dispersed on the surface of melamine sponge carbon skeleton and Co-containing sample exhibits the highest CNTs concentration.The minimum reflection loss(RL_(min))of the CoZnC/MS composite(m_(composite):m_(paraffin)=1:1,m represents mass)reached-33.60 dB,and the effective absorption bandwidth(EAB)reached 9.60 GHz.The outstanding electromagnetic wave absorption(EMWA)properties of the CoZnC/MS composite can be attributed to its unique hollow structure,which leads to multiple reflections and scattering.The formed conductive network improves dielectric and conductive loss.The incorporation of Co enhances the magnetic loss capability and optimizes interfacial polarization and dipole polarization.By simultaneously improving dielectric and magnetic losses,ex-cellent impedance matching performance is achieved.The clarification of element replacement in XZnC/MS composites provides an effi-cient design perspective for high-performance non-stoichiometric carbide EMW absorbers.展开更多
Precise coseismic displacements in earthquake/tsunamic early warning are necessary to characterize earthquakes in real time in order to enable decision-makers to issue alerts for public safety.Real-time global navigat...Precise coseismic displacements in earthquake/tsunamic early warning are necessary to characterize earthquakes in real time in order to enable decision-makers to issue alerts for public safety.Real-time global navigation satellite systems(GNSSs)have been a valuable tool in monitoring seismic motions,allowing permanent displacement computation to be unambiguously achieved.As a valuable tool presented to the seismic commu nity,the GSeisRT software developed by Wuhan University(China)can realize multi-GNSS precise point positioning with ambiguity resolution(PPP-AR)and achieve centimeterlevel to sub-centimeter-level precision in real time.While the stable maintenance of a global precise point positioning(PPP)service is challenging,this software is capable of estimating satellite clocks and phase biases in real time using a regional GNSS network.This capability makes GSeisRT especially suitable for proprietary GNSS networks and,more importantly,the highest possible positio ning precision and reliability can be obtained.According to real-time results from the Network of the Americas,the mean root mean square(RMS)errors of kinematic PPP-AR over a 24 h span are as low as 1.2,1.3,and 3.0 cm in the east,north,and up components,respectively.Within the few minutes that span a typical seismic event,a horizontal displacement precision of 4 mm can be achieved.The positioning precision of the GSeisRT regional PPP/PPP-AR is 30%-40%higher than that of the global PPP/PPP-AR.Since 2019,GSeisRT has successfully recorded the static,dynamic,and peak ground displacements for the 2020Oaxaca,Mexico moment magnitude(Mw)7.4 event;the 2020 Lone Pine,California Mw 5.8 event;and the 2021 Qinghai,China Mw 7.3 event in real time.The resulting immediate magnitude estimates have an error of around 0.1 only.The GSeisRT software is open to the scientific community and has been applied by the China Earthquake Ne tworks Center,the EarthScope Consortium of the United States,the National Seismological Center of Chile,Institute of Geological and Nuclear Sciences Limited(GNS Science Te PūAo)of New Zealand,and the Geospatial Information Agency of Indonesia.展开更多
基金The National Key Research and Development Program of China under contract No. 2020YFD0900803the National Natural Science Foundation of China under contract Nos 41976157 and 42076177+1 种基金the Science Technology Department of Zhejiang Province under contract No. 2022C03044the State Key Laboratory of Satellite Ocean Environment Dynamics of the Ministry of Natural Resources of China under contract No. QNHX1807。
文摘Channel dredging in estuaries increases water depth and subsequently impacts sediment dynamics and morphology. The Jiaojiang River Estuary is dredged frequently owing to heavy shipping demands. In this study,the effects of different dredging schemes on siltation were assessed through numerical modeling. The sediment model of the Jiaojiang River Estuary utilized an optimized bottom boundary layer model that considered the bed sediment grain size and fluid mud, and this model was calibrated using field data. Result reveal that channel dredging modifies the flow velocity inside and around the channel by changing the bathymetry;subsequently, this affects the residual current, bed stress, suspended sediment concentration, and sediment fluxes. Increasing the dredging depth and width increases the net sediment fluxes into the channel and dredging depth has a greater influence on the channel siltation thickness. When the dredging depth is 8.4 m or11.4 m, the average siltation thickness of the channel is 0.07 m or 0.15 m per mouth respectively. The parallel movement of the channel has small effects on the siltation volume during the simulation period. The sediment deposits in the channel primarily originates from the tidal flats, through bottom sediment fluxes. Vertical net circulation has a dominant impact on siltation because the difference of horizontal current of each layer on the longitudinal section of the channel increases, which intensifies the lateral sediment transport between the shoal and channel. The influence of vertical frictional dissipation on the lateral circulation at the feature points accounts for more than 50% before dredging, while the non-linear advective term is dominant after dredging. Tidal pumping mainly affects the longitudinal sediment fluxes in the channel. These results can be used for channel management and planning for similar estuaries worldwide.
基金Project supported by the Ministry of Higher Education and Scientific Research,Algeria(CNEPRU No.A10N01UN210120150002)
文摘We propose a novel approach called the robust fractional-order proportional-integral-derivative（FOPID）controller, to stabilize a perturbed nonlinear chaotic system on one of its unstable fixed points. The stability analysis of the nonlinear chaotic system is made based on the proportional-integral-derivative actions using the bifurcation diagram. We extract an initial set of controller parameters, which are subsequently optimized using a quadratic criterion. The integral and derivative fractional orders are also identified by this quadratic criterion. By applying numerical simulations on two nonlinear systems, namely the multi-scroll Chen system and the Genesio-Tesi system,we show that the fractional PI~λD~μ controller provides the best closed-loop system performance in stabilizing the unstable fixed points, even in the presence of random perturbation.
基金The authors are also grateful for the Rio de Janeiro Research Fundation(FAFERJ),National Council for Scientific and Technological Development(CNPQ)and Coordenaç˜ao de Aperfeiçoamento de Pessoal de Nível Superior(CAPES)for the financial support.A.G.Cruz and M.Q.Freitas are grateful to the productivity grants(CNPQ).
文摘The effect of sodium reduction and Lactobacillus acidophilus addition(free or microencapsulated)on the quality parameters of requeijao cremoso processed cheese was assessed for 90 days at 5℃.Three formulations were prepared:(CONT)regular salt content and curd fusion(90℃/2 min),(FREE)reduced salt content+free probiotic culture added after curd fusion(90℃/2 min),and(MICRO)reduced salt content+microencapsulated probiotic culture added before curd fusion(70℃/5 min).FREE and MICRO formulations showed increased monounsaturated and polyunsaturated fatty acid content,improved health indices(decreases in thrombogenic index and increases in desirable fatty acid index),and altered rheological properties(higher consistency index,apparent viscosity,elastic properties,and gel strength).In addition,the MICRO formulation showed higher texture sensory acceptance and probiotic counts higher than 6 log CFU/g during storage and simulated gastrointestinal conditions.Overall,microencapsulation of probiotics with spray chilling represents an innovative solution in requeijao cremoso processed cheese.
基金the European Research Council(ERC Advanced MechAGE-ERC-2016-ADG-741883)the Swiss National Science Foundation(no.188522).
文摘Age-related osteoporosis poses a significant challenge in musculoskeletal health;a condition characterized by reduced bone density and increased fracture susceptibility in older individuals necessitates a better understanding of underlying molecular and cellular mechanisms.Emerging evidence suggests that osteocytes are the pivotal orchestrators of bone remodeling and represent novel therapeutic targets for age-related bone loss.Our study uses the prematurely aged PolgD257A/D257A(PolgA)mouse model to scrutinize age-and sex-related alterations in musculoskeletal health parameters(frailty,grip strength,gait data),bone and particularly the osteocyte lacuno-canalicular network(LCN).Moreover,a new quantitative in silico image analysis pipeline is used to evaluate the alterations in the osteocyte network with aging.Our findings underscore the pronounced degenerative changes in the musculoskeletal health parameters,bone,and osteocyte LCN in PolgA mice as early as 40 weeks,with more prominent alterations evident in aged males.Our findings suggest that the PolgA mouse model serves as a valuable model for studying the cellular mechanisms underlying age-related bone loss,given the comparable aging signs and age-related degeneration of the bone and the osteocyte network observed in naturally aging mice and elderly humans.
基金supported by the National Natural Science Foundation of China(Nos.52101274,52377026 and 52472131)Taishan Scholars and Young Experts Program of Shandong Province,China(No.tsqn202103057)+4 种基金Natural Science Foundation of Shandong Province,China(Nos.ZR2020QE011 and ZR2022ME089)the Qingchuang Talents Induction Program of Shandong Higher Education Institution,China(Research and Innovation Team of Structural-Functional Polymer Composites)Youth Top Talent Foundation of Yantai University,China(No.2219008)Graduate Innovation Foundation of Yantai University,China(No.GIFYTU2240)College Student Innovation and Entrepreneurship Training Program Project,China(No.202311066088).
文摘Non-stoichiometric carbides have been proven to be effective electromagnetic wave(EMW)absorbing materials.In this study,phase and morphology of XZnC(X=Fe/Co/Cu)loaded on a three dimensional(3D)network structure melamine sponge(MS)carbon composites were investigated through vacuum filtration followed by calcination.The FeZnC/CoZnC/CuZnC with carbon nanotubes(CNTs)were uniformly dispersed on the surface of melamine sponge carbon skeleton and Co-containing sample exhibits the highest CNTs concentration.The minimum reflection loss(RL_(min))of the CoZnC/MS composite(m_(composite):m_(paraffin)=1:1,m represents mass)reached-33.60 dB,and the effective absorption bandwidth(EAB)reached 9.60 GHz.The outstanding electromagnetic wave absorption(EMWA)properties of the CoZnC/MS composite can be attributed to its unique hollow structure,which leads to multiple reflections and scattering.The formed conductive network improves dielectric and conductive loss.The incorporation of Co enhances the magnetic loss capability and optimizes interfacial polarization and dipole polarization.By simultaneously improving dielectric and magnetic losses,ex-cellent impedance matching performance is achieved.The clarification of element replacement in XZnC/MS composites provides an effi-cient design perspective for high-performance non-stoichiometric carbide EMW absorbers.
基金funded by National Science Foundation of China(42025401)National Key Research and Development Program of China(2022YFB3903800)。
文摘Precise coseismic displacements in earthquake/tsunamic early warning are necessary to characterize earthquakes in real time in order to enable decision-makers to issue alerts for public safety.Real-time global navigation satellite systems(GNSSs)have been a valuable tool in monitoring seismic motions,allowing permanent displacement computation to be unambiguously achieved.As a valuable tool presented to the seismic commu nity,the GSeisRT software developed by Wuhan University(China)can realize multi-GNSS precise point positioning with ambiguity resolution(PPP-AR)and achieve centimeterlevel to sub-centimeter-level precision in real time.While the stable maintenance of a global precise point positioning(PPP)service is challenging,this software is capable of estimating satellite clocks and phase biases in real time using a regional GNSS network.This capability makes GSeisRT especially suitable for proprietary GNSS networks and,more importantly,the highest possible positio ning precision and reliability can be obtained.According to real-time results from the Network of the Americas,the mean root mean square(RMS)errors of kinematic PPP-AR over a 24 h span are as low as 1.2,1.3,and 3.0 cm in the east,north,and up components,respectively.Within the few minutes that span a typical seismic event,a horizontal displacement precision of 4 mm can be achieved.The positioning precision of the GSeisRT regional PPP/PPP-AR is 30%-40%higher than that of the global PPP/PPP-AR.Since 2019,GSeisRT has successfully recorded the static,dynamic,and peak ground displacements for the 2020Oaxaca,Mexico moment magnitude(Mw)7.4 event;the 2020 Lone Pine,California Mw 5.8 event;and the 2021 Qinghai,China Mw 7.3 event in real time.The resulting immediate magnitude estimates have an error of around 0.1 only.The GSeisRT software is open to the scientific community and has been applied by the China Earthquake Ne tworks Center,the EarthScope Consortium of the United States,the National Seismological Center of Chile,Institute of Geological and Nuclear Sciences Limited(GNS Science Te PūAo)of New Zealand,and the Geospatial Information Agency of Indonesia.
