Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among...Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among them,flexible solid-state zinc-air batteries have received widespread attention because of their high energy density,good safety,and stability.Efficient bifunctional oxygen electrocatalysts are the primary consideration in the development of flexible solid-state zinc-air batteries,and self-supported air cathodes are strong candidates because of their advantages including simplified fabrication process,reduced interfacial resistance,accelerated electron transfer,and good flexibility.This review outlines the research progress in the design and construction of nanoarray bifunctional oxygen electrocatalysts.Starting from the configuration and basic principles of zinc-air batteries and the strategies for the design of bifunctional oxygen electrocatalysts,a detailed discussion of self-supported air cathodes on carbon and metal substrates and their uses in flexible zinc-air batteries will follow.Finally,the challenges and opportunities in the development of flexible zinc-air batteries will be discussed.展开更多
Extreme droughts are increasing in frequency and severity globally as a result of climate change.Developing understanding of species’responses to drought is crucial for their conservation,especially in regions experi...Extreme droughts are increasing in frequency and severity globally as a result of climate change.Developing understanding of species’responses to drought is crucial for their conservation,especially in regions experi-encing increased aridity.Although numerous studies have investigated birds’responses to drought,the emphasis has primarily been on landbirds.Drought can significantly alter the wetland environments that waterbirds inhabit,but the response of waterbirds to drought remains understudied.In this study,we surveyed the distri-bution and behavior of Oriental Storks(Ciconia boyciana)in Poyang Lake,which is the largest freshwater lake in China.Results indicate that drought-induced catchment areas at the lowest water level limited the total popu-lation size of Oriental Storks in the sub-lakes.Sub-lakes with large catchment areas at the lowest water level demonstrated a capacity to support a larger population of wintering Oriental Storks.Over time,Oriental Storks exhibited a gradual concentration in Changhu Lake,characterized by larger catchments,after resource depletion in sub-lakes with smaller catchments.Additionally,the duration of Oriental Storks’vigilance and moving be-haviors decreased significantly compared with that observed before the drought.After the drought,Oriental Storks increased their foraging efforts,as evidenced by increased presence in deeper water and reaching their heads and necks into deeper water to forage,higher search rates,but lower foraging rates.In accordance with area-restricted search theory,reductions in habitat quality resulting from drought,including extensive fish die-offs,forced Oriental Storks to increase their foraging efforts.Sustaining a specific water area in sub-lakes during droughts can preserve resource availability,which is crucial for the conservation of Oriental Storks.Imple-menting measures such as water level control and micro-modification of lake bottoms in sub-lakes might mitigate the impact of drought on the piscivorous Oriental Storks.展开更多
The‘15-minute city’(15minC)concept,which aspires to bring essential services within reach via a 15-minute walk for all residents,represents a pivotal paradigm shift in sustainable urban development.However,the achie...The‘15-minute city’(15minC)concept,which aspires to bring essential services within reach via a 15-minute walk for all residents,represents a pivotal paradigm shift in sustainable urban development.However,the achievability of this concept for different cities varies considerably across diverse population distributions,urban contexts,and development priorities.In this study,we propose a robust method for evaluating a city’s 15minC potential-a city’s capability to achieve widespread 15-minute accessibility while maintaining an optimal balance between resource efficiency and resident accessibility.We employ the Location Set Covering Problem optimization model to analyze the resources required to achieve full coverage of 15-minute accessibility and the knee point detection algorithm to assess a city’s 15minC potential.Across 23 major Chinese cities,our method exhibits a sharp sensitivity to delineate distinct 15minC potentials.It reveals that cities’current 15minC development level doesn’t align with their inherent potential uniformly.Key determinants include how well current facility locations match population centers and the population density in remote areas.Further,reducing facility constructions by twothirds has only a marginal impact on accessibility,emphasizing the need for tailored,data-driven planning in effective and sustainable urban development based on the distinct potentials of cities.Our approach prioritizes resource efficiency,minimizing the inefficient use of facilities that serve only a small portion of residents while maximizing the benefits of the 15minC and therefore has significant implications for a sustainable urban future.展开更多
Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity...Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity,selectivity and long-term durability are required for the future up-scaling industrial applications.Herein,we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol(EG,derived from PET hydrolysate) oxidation to formic acid.The interfacial modification between Fe_(2)O_(3)semiconductor and Ni(OH)xcocatalyst with ultrathin TiO_(x) interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers,but also kept the high Faradaic efficiency(over 95% in 30 h) towards the value-added formic acid product.This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.展开更多
Groundwater environment evolution can comprehensively reflect groundwater dynamics. Based on the relationship between the groundwater system and the external environment in Jinghuiqu irrigation district, adopting the ...Groundwater environment evolution can comprehensively reflect groundwater dynamics. Based on the relationship between the groundwater system and the external environment in Jinghuiqu irrigation district, adopting the Principal Component Analysis method, variation characteristics of environmental factors including climate and human activity and their impact on groundwater were systematically analyzed. The results show that groundwater level in Jinghuiqu irrigation district has been significantly dropped in nearly 34 years;the reduction of surface water irrigation use, which reduced the amounts of groundwater recharge and destroyed the water balance, is considered as the most direct cause for falling of regional groundwater level. Besides, reduction in precipitation, increase of evaporation also accelerated the declining of the groundwater level at some extent. Finally, a predicting method of groundwater depth based on BP neural network is developed. The experimental results show that the predicting model can reasonablely predict the groundwater level in Jinghuiqu irrigation district with a high precision.展开更多
This paper investigates the pose and motion estimation problem using single camera measurement for spacecraft. The leader spacecraft of three-dimensional shape is observed by a calibrated camera fixed on the follower ...This paper investigates the pose and motion estimation problem using single camera measurement for spacecraft. The leader spacecraft of three-dimensional shape is observed by a calibrated camera fixed on the follower spacecraft. Based on dual numbers,an integrated observation model is proposed based on a combination of multiple geometric features including points,lines and circles,which can improve the robustness and accuracy of the estimation algorithm. A six-degree-of-freedom relative motion model is proposed by using the dual quaternion representation,in which the rotation-translation coupling effect due to the points deviating from the center of the mass is described. Employing the proposed observation model and dynamics model,an Extended Kalman Filter is presented to estimate the relative state between the two spacecraft. Numerical simulations are performed to evaluate the proposed approaches,showing the convergence of relative estimation errors and superior estimation performance.展开更多
A kind of aquatic gelatin was prepared from squid skin. The technological parameters for extracting gelatin were optimized by the method of orthogonal design. The fundamental properties of the raw material and gelatin...A kind of aquatic gelatin was prepared from squid skin. The technological parameters for extracting gelatin were optimized by the method of orthogonal design. The fundamental properties of the raw material and gelatin were analyzed. The results showed that the optimal extraction conditions were as follows： pH val- ue of 8, temperature at 70 ℃, material-to-liquid ratio at 1：4, and extraction time of 1.5 h. under such conditions, the highest yield of gelatin and the purity were 5.94% and 96.73%, respectively. The physicoehemical properties of squid skin gelatin were coincided with standards of edible gelatin. In addition, the contents of amino acids were similar to many kinds of aquatic gelatin.展开更多
Excessive urbanization leads to considerable nature deficiency and abundant artificial infrastructure in urban areas,which triggered intensive discussions on people's exposure to green space and outdoor artificial...Excessive urbanization leads to considerable nature deficiency and abundant artificial infrastructure in urban areas,which triggered intensive discussions on people's exposure to green space and outdoor artificial light at night(ALAN).Recent academic progress highlights that people's exposure to green space and outdoor ALAN may be confounders of each other but lacks systematic investigations.This study investigates the associations between people's exposure to green space and outdoor ALAN by adopting the three most used research paradigms:population-level residence-based,individual-level residencebased,and individual-level mobility-oriented paradigms.We employed the green space and outdoor ALAN data of 291 Tertiary Planning Units in Hong Kong for population-level analysis.We also used data from 940 participants in six representative communities for individual-level analyses.Hong Kong green space and outdoor ALAN were derived from high-resolution remote sensing data.The total exposures were derived using the spatiotemporally weighted approaches.Our results confirm that the negative associations between people's exposure to green space and outdoor ALAN are universal across different research paradigms,spatially non-stationary,and consistent among different socio-demographic groups.We also observed that mobility-oriented measures may lead to stronger negative associations than residence-based measures by mitigating the contextual errors of residence-based measures.Our results highlight the potential confounding associations between people's exposure to green space and outdoor ALAN,and we strongly recommend relevant studies to consider both of them in modeling people's health outcomes,especially for those health outcomes impacted by the co-exposure to them.展开更多
In order to alleviate the impact of turbulence on the performance of underwater wireless optical communication(UWOC)in real time,and achieve high-speed real-time transmission and low cost and miniaturization of equipm...In order to alleviate the impact of turbulence on the performance of underwater wireless optical communication(UWOC)in real time,and achieve high-speed real-time transmission and low cost and miniaturization of equipment,a 2×2 real-time multiple-input and multiple-output(MIMO)high-speed miniaturized UWOC system based on a field-programmable gate array(FPGA)and a high-power light-emitting diode(LED)array is designed in this Letter.In terms of multiplexing gain,the imaging MIMO spatial multiplexing and high-order modulation for the first time are combined and the real-time high-speed transmission of PAM-4 signal based on the LED array light source in 12 m underwater channel at 100 Mbps rate is implemented,which effectively improves the throughput of the UWOC system with a high-power commercial LED light source.In light of diversity gain,the system employs the diversity of repeated coding scheme to receive two identical non-return-to-zero on-off keying(NRZ-OOK)signals,which can compensate the fading or flickering sublinks in real time under the bubble-like simulated turbulence condition,and has high robustness.To our knowledge,this is the first instance of a high rate and long-distance implementation of a turbulence-resistant real-time MIMO miniaturized UWOC system based on FPGA and high-power LED arrays.With spatial diversity or spatial multiplexing capabilities,its low cost,integrity,and high robustness provide the system with important practical prospects.展开更多
Non-alcoholic fatty liver disease(NAFLD)is a liver condition that is widely prevalent across the world.A considerable number of people with NAFLD have the potential to progress to a more severe form of the condition k...Non-alcoholic fatty liver disease(NAFLD)is a liver condition that is widely prevalent across the world.A considerable number of people with NAFLD have the potential to progress to a more severe form of the condition known as nonalcoholic steatohepatitis(NASH),accompanied by bridging fibrosis.This advancement is more likely if the patient has metabolic risk factors such as obesity or type 2 diabetes that deteriorate over time.Additionally,even slight inflammation or fibrosis in NAFLD can significantly increase the likelihood of progression compared to steatosis alone.This underscores the importance of revising the present methods of monitoring NAFLD patients to ensure early detection and effective management of the disease.展开更多
The optimal guidance problem for an interceptor against a ballistic missile with active defense is investigated in this paper.A class of optimal guidance schemes are proposed based on linear quadratic differential gam...The optimal guidance problem for an interceptor against a ballistic missile with active defense is investigated in this paper.A class of optimal guidance schemes are proposed based on linear quadratic differential game method and numerical solution of Riccati differential equation.By choosing proper parameters, the proposed guidance schemes are able to drive the interceptor to the target and away from the defender simultaneously.Additionally, fuel cost, control saturation,chattering phenomenon and parameters selection were taken into account.Satisfaction of the proposed guidance schemes of the saddle point condition is proven theoretically.Finally, nonlinear numerical examples are included to demonstrate the effectiveness and performance of the developed guidance approaches.Comparison of control performance between different guidance schemes are presented and analysis.展开更多
Lingguizhugan Decoction(LGZG)has been investigated in basic studies,with satisfactory effects on insulin resistance in non-alcoholic fatty liver disease(NAFLD).This translational approach aimed to explore the effect a...Lingguizhugan Decoction(LGZG)has been investigated in basic studies,with satisfactory effects on insulin resistance in non-alcoholic fatty liver disease(NAFLD).This translational approach aimed to explore the effect and underlying mechanism of LGZG in clinical setting.A randomized,double-blinded,placebo-controlled trial was performed.A total of 243 eligible participants with NAFLD were equally allocated to receive LGZG(two groups:standard dose and low dose)or placebo for 12 weeks on the basis of lifestyle modifications.The primary efficacy variable was homeostasis model assessment of insulin resistance(HOMA-IR).Analyses were performed in two populations in accordance with body mass index(BMI;overweight/obese,BMI 24 kg/m^(2);lean,BMI<24 kg/m^(2)).For overweight/obese participants,low-dose LGZG significantly decreased their HOMA-IR level compared with placebo(0.19(1.47)versus 0.08(1.99),P=0.038).For lean subjects,neither dose of LGZG showed a superior effect compared with placebo.Methylated DNA immunoprecipitation sequencing and real-time qPCR found that the DNA N6-methyladenine modification levels of protein phosphatase 1 regulatory subunit 3A(PPP1R3A)and autophagy related 3(ATG3)significantly increased after LGZG intervention in overweight/obese population.Low-dose LGZG effectively improved insulin resistance in overweight/obese subjects with NAFLD.The underlying mechanism may be related to the regulation of DNA N6-methyladenine modification of PPP1R3A and ATG3.Lean subjects may not be a targeted population for LGZG.展开更多
The selective laser melting(SLM)with subsequent cold rolling and annealing is used to produce high-density lattice defects and grain refinement in the CoCrNi medium-entropy alloys(MEAs).The superior comprehensive mech...The selective laser melting(SLM)with subsequent cold rolling and annealing is used to produce high-density lattice defects and grain refinement in the CoCrNi medium-entropy alloys(MEAs).The superior comprehensive mechanical properties have been achieved in the as-SLMed CoCrNi alloy after rolling and annealing.The as-SLMed alloys delivered the yield strength of 693.4 MPa,the ultimate tensile strength of 912.7 MPa and the fracture strain of 54.4%.After rolling with 70%reduction in thickness and annealing at 700℃for 2 h.the yield strength,ultimate tensile strength and fracture strain reached 1161.6 MPa,1390.8 MPa and 31.5%,respectively.The exceptional strength-ductility synergy is mainly attributed to the refined hierarchical microstructures with coarsening grains at a level of 30μm and ultrafine grains at a level of 1μm,and the heritage of dislocation-formed sub-grains and other lattice defects.This investigation demonstrates that the SLM with subsequent rolling and annealing is beneficial to fabricate high strength and ductile MEAs with single face-centered cubic(fcc)structure.展开更多
The coarsening-grained single-phase face-centered cubic(fcc)medium-entropy alloys(MEAs)normally exhibit insufficient strength for some engineering applications.Here,superior mechanical properties with ultimate tensile...The coarsening-grained single-phase face-centered cubic(fcc)medium-entropy alloys(MEAs)normally exhibit insufficient strength for some engineering applications.Here,superior mechanical properties with ultimate tensile strength of 1.6 GPa and fracture strain of 13.1%at ambient temperature have been achieved in a(CoCrNi)_(94)Ti_(3)Al_(3)MEA by carefully architecting the multi-scale heterogeneous structures.Electron microscopy characterization indicates that the superior mechanical properties mainly originated from the favorable heterogeneous fcc matrix(1-40μm)and the coherent sphericalγ’precipitates(10-100 nm),together with a high number density of crystalline defects(2-10 nm),including dislocations,small stacking faults,Lomer-Cottrell locks,and ultrafine deformation twins.展开更多
A novel Al-5 Mg2 Si-2 Mg alloy was processed by selective laser melting(SLM) to understand its representative features of microstructural evolution and mechanical properties during additive manufacturing(AM). The as-S...A novel Al-5 Mg2 Si-2 Mg alloy was processed by selective laser melting(SLM) to understand its representative features of microstructural evolution and mechanical properties during additive manufacturing(AM). The as-SLM fabricated Al-5 Mg_(2) Si-2 Mg alloy is found to deliver much less hot cracks and other defects. Meanwhile, excellent mechanical property is also achieved, i.e. 452 ± 11 MPa for ultimate tensile strength, 295 ± 14 MPa for yield strength, and 9.3 ± 2.5% for elongation. Clearly, these mechanical properties are better than that obtained by high pressure die casting(HPDC), and better than some other alloys obtained by SLM. The as-SLM fabricated Al-5 Mg_(2) Si-2 Mg alloy is featured by the significantly refined microstructures in the compact primary α-Al, the divorced Mg_(2) Si eutectic networks distributing atα-Al grain boundaries, and some α-Al Fe Mn Si phase in association with eutectic Mg_(2) Si phase. The high strength and ductility of the alloy are attributed to its unique features including(a) the reduced solidification range,(b) the possible increase of the eutectic level in the microstructure, and(c) the shift of eutectic point and the maximum solubility point of Mg2 Si in Al matrix.展开更多
Pharmaceutical cocrystals are a promising technology that can be used to improve the solubility of poor aqueous compounds. The objective of this study was to systematically investigate the solubility of myricetin(MYR)...Pharmaceutical cocrystals are a promising technology that can be used to improve the solubility of poor aqueous compounds. The objective of this study was to systematically investigate the solubility of myricetin(MYR) cocrystals, including their kinetic solubility, thermodynamic solubility, and intrinsic dissolution rate(IDR). The effects of pH, surfactant, ion concentration, and coformers on the cocrystal solubility were evaluated. Furthermore, single crystal structures of MYR, myricetin–isonicotinamide(MYR–INM) and myricetin–caffeine(MYR–CAF) cocrystals were analyzed to discuss the possible reasons for the enhancement of cocrystal solubility from the perspective of the spatial structure.The results indicated that the kinetic solubility of MYR cocrystals was modulated by pH and cocrystal coformer(CCF) ionization in buffer solution, while it primarily depended on the CCF solubility in pure water. In addition, the solubility of MYR cocrystals was increased in a concentration dependent fashion by the surfactant or ion concentration. The thermodynamic solubility of MYR–INM(1:3) cocrystals decreased with the increases of the pH value of the dissolution media. The IDR of MYR cocrystals was faster than that of MYR in the same medium and extremely fast in pH 4.5 buffer. The improved solubility of MYR cocrystals was probably related to the alternate arrangements of MYR and INM/CAF molecules and increased intermolecular distance. The present study provides some references to investigate the solubility behavior of pharmaceutical cocrystals.展开更多
基金supported by the National Natural Science Foundation of China(22072107,21872105)the Natural Science Foundation of Shanghai(23ZR1464800)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Science&Technology Commission of Shanghai Municipality(19DZ2271500)。
文摘Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among them,flexible solid-state zinc-air batteries have received widespread attention because of their high energy density,good safety,and stability.Efficient bifunctional oxygen electrocatalysts are the primary consideration in the development of flexible solid-state zinc-air batteries,and self-supported air cathodes are strong candidates because of their advantages including simplified fabrication process,reduced interfacial resistance,accelerated electron transfer,and good flexibility.This review outlines the research progress in the design and construction of nanoarray bifunctional oxygen electrocatalysts.Starting from the configuration and basic principles of zinc-air batteries and the strategies for the design of bifunctional oxygen electrocatalysts,a detailed discussion of self-supported air cathodes on carbon and metal substrates and their uses in flexible zinc-air batteries will follow.Finally,the challenges and opportunities in the development of flexible zinc-air batteries will be discussed.
基金funded by the National Natural Science Foundation of China(Grant No.32360142).
文摘Extreme droughts are increasing in frequency and severity globally as a result of climate change.Developing understanding of species’responses to drought is crucial for their conservation,especially in regions experi-encing increased aridity.Although numerous studies have investigated birds’responses to drought,the emphasis has primarily been on landbirds.Drought can significantly alter the wetland environments that waterbirds inhabit,but the response of waterbirds to drought remains understudied.In this study,we surveyed the distri-bution and behavior of Oriental Storks(Ciconia boyciana)in Poyang Lake,which is the largest freshwater lake in China.Results indicate that drought-induced catchment areas at the lowest water level limited the total popu-lation size of Oriental Storks in the sub-lakes.Sub-lakes with large catchment areas at the lowest water level demonstrated a capacity to support a larger population of wintering Oriental Storks.Over time,Oriental Storks exhibited a gradual concentration in Changhu Lake,characterized by larger catchments,after resource depletion in sub-lakes with smaller catchments.Additionally,the duration of Oriental Storks’vigilance and moving be-haviors decreased significantly compared with that observed before the drought.After the drought,Oriental Storks increased their foraging efforts,as evidenced by increased presence in deeper water and reaching their heads and necks into deeper water to forage,higher search rates,but lower foraging rates.In accordance with area-restricted search theory,reductions in habitat quality resulting from drought,including extensive fish die-offs,forced Oriental Storks to increase their foraging efforts.Sustaining a specific water area in sub-lakes during droughts can preserve resource availability,which is crucial for the conservation of Oriental Storks.Imple-menting measures such as water level control and micro-modification of lake bottoms in sub-lakes might mitigate the impact of drought on the piscivorous Oriental Storks.
基金supported by grants from the Hong Kong Research Grants Council(General Research Fund Grants No.14605920,14611621,14606922,14603724Collaborative Research Fund Grant No.C4023-20GF+2 种基金Research Matching Grants No.8601219,8601242,3110156)a grant from the Research Committee on Research Sustainability of Major Research Grants Council Funding Schemes(Grant No.3133235)of the Chinese University of Hong Kongfunding from the Improvement on Competitiveness in Hiring New Faculties Funding Scheme of The Chinese University of Hong Kong.
文摘The‘15-minute city’(15minC)concept,which aspires to bring essential services within reach via a 15-minute walk for all residents,represents a pivotal paradigm shift in sustainable urban development.However,the achievability of this concept for different cities varies considerably across diverse population distributions,urban contexts,and development priorities.In this study,we propose a robust method for evaluating a city’s 15minC potential-a city’s capability to achieve widespread 15-minute accessibility while maintaining an optimal balance between resource efficiency and resident accessibility.We employ the Location Set Covering Problem optimization model to analyze the resources required to achieve full coverage of 15-minute accessibility and the knee point detection algorithm to assess a city’s 15minC potential.Across 23 major Chinese cities,our method exhibits a sharp sensitivity to delineate distinct 15minC potentials.It reveals that cities’current 15minC development level doesn’t align with their inherent potential uniformly.Key determinants include how well current facility locations match population centers and the population density in remote areas.Further,reducing facility constructions by twothirds has only a marginal impact on accessibility,emphasizing the need for tailored,data-driven planning in effective and sustainable urban development based on the distinct potentials of cities.Our approach prioritizes resource efficiency,minimizing the inefficient use of facilities that serve only a small portion of residents while maximizing the benefits of the 15minC and therefore has significant implications for a sustainable urban future.
基金supported by the NSFC(21777096,21777097)the Ministry of Science and Technology of China(2018YFC1802001)+1 种基金the OU–SJTU strategic partnership development fundInternational Joint Research Promotion Program in Osaka University。
文摘Photoelectrochemical(PEC) technology provides a promising prospect for the transformation of polyethylene terephthalate(PET) plastic wastes to produce value-added chemicals.The PEC catalytic systems with high activity,selectivity and long-term durability are required for the future up-scaling industrial applications.Herein,we employed the interfacial modification strategy to develop an efficient and stable photoanode and evaluated its PEC activity for ethylene glycol(EG,derived from PET hydrolysate) oxidation to formic acid.The interfacial modification between Fe_(2)O_(3)semiconductor and Ni(OH)xcocatalyst with ultrathin TiO_(x) interlayer not only improved the photocurrent density by accelerating the kinetics of photogenerated charge carriers,but also kept the high Faradaic efficiency(over 95% in 30 h) towards the value-added formic acid product.This work proposes an effective method to promote the PEC activity and enhance the long-term stability of photoelectrodes for upcycling PET plastic wastes.
文摘Groundwater environment evolution can comprehensively reflect groundwater dynamics. Based on the relationship between the groundwater system and the external environment in Jinghuiqu irrigation district, adopting the Principal Component Analysis method, variation characteristics of environmental factors including climate and human activity and their impact on groundwater were systematically analyzed. The results show that groundwater level in Jinghuiqu irrigation district has been significantly dropped in nearly 34 years;the reduction of surface water irrigation use, which reduced the amounts of groundwater recharge and destroyed the water balance, is considered as the most direct cause for falling of regional groundwater level. Besides, reduction in precipitation, increase of evaporation also accelerated the declining of the groundwater level at some extent. Finally, a predicting method of groundwater depth based on BP neural network is developed. The experimental results show that the predicting model can reasonablely predict the groundwater level in Jinghuiqu irrigation district with a high precision.
文摘This paper investigates the pose and motion estimation problem using single camera measurement for spacecraft. The leader spacecraft of three-dimensional shape is observed by a calibrated camera fixed on the follower spacecraft. Based on dual numbers,an integrated observation model is proposed based on a combination of multiple geometric features including points,lines and circles,which can improve the robustness and accuracy of the estimation algorithm. A six-degree-of-freedom relative motion model is proposed by using the dual quaternion representation,in which the rotation-translation coupling effect due to the points deviating from the center of the mass is described. Employing the proposed observation model and dynamics model,an Extended Kalman Filter is presented to estimate the relative state between the two spacecraft. Numerical simulations are performed to evaluate the proposed approaches,showing the convergence of relative estimation errors and superior estimation performance.
文摘A kind of aquatic gelatin was prepared from squid skin. The technological parameters for extracting gelatin were optimized by the method of orthogonal design. The fundamental properties of the raw material and gelatin were analyzed. The results showed that the optimal extraction conditions were as follows： pH val- ue of 8, temperature at 70 ℃, material-to-liquid ratio at 1：4, and extraction time of 1.5 h. under such conditions, the highest yield of gelatin and the purity were 5.94% and 96.73%, respectively. The physicoehemical properties of squid skin gelatin were coincided with standards of edible gelatin. In addition, the contents of amino acids were similar to many kinds of aquatic gelatin.
基金supported by grants from the Hong Kong Research Grants Council(General Research Fund Grant no.14605920,14611621,14606922Collaborative Research Fund Grant no.C4023-20GF+1 种基金Research Matching Grants RMG 8601219,8601242)a grant from the Research Committee on Research Sustainability of Major Research Grants Council Funding Schemes(3133235)of the Chinese University of Hong Kong.
文摘Excessive urbanization leads to considerable nature deficiency and abundant artificial infrastructure in urban areas,which triggered intensive discussions on people's exposure to green space and outdoor artificial light at night(ALAN).Recent academic progress highlights that people's exposure to green space and outdoor ALAN may be confounders of each other but lacks systematic investigations.This study investigates the associations between people's exposure to green space and outdoor ALAN by adopting the three most used research paradigms:population-level residence-based,individual-level residencebased,and individual-level mobility-oriented paradigms.We employed the green space and outdoor ALAN data of 291 Tertiary Planning Units in Hong Kong for population-level analysis.We also used data from 940 participants in six representative communities for individual-level analyses.Hong Kong green space and outdoor ALAN were derived from high-resolution remote sensing data.The total exposures were derived using the spatiotemporally weighted approaches.Our results confirm that the negative associations between people's exposure to green space and outdoor ALAN are universal across different research paradigms,spatially non-stationary,and consistent among different socio-demographic groups.We also observed that mobility-oriented measures may lead to stronger negative associations than residence-based measures by mitigating the contextual errors of residence-based measures.Our results highlight the potential confounding associations between people's exposure to green space and outdoor ALAN,and we strongly recommend relevant studies to consider both of them in modeling people's health outcomes,especially for those health outcomes impacted by the co-exposure to them.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61871418)。
文摘In order to alleviate the impact of turbulence on the performance of underwater wireless optical communication(UWOC)in real time,and achieve high-speed real-time transmission and low cost and miniaturization of equipment,a 2×2 real-time multiple-input and multiple-output(MIMO)high-speed miniaturized UWOC system based on a field-programmable gate array(FPGA)and a high-power light-emitting diode(LED)array is designed in this Letter.In terms of multiplexing gain,the imaging MIMO spatial multiplexing and high-order modulation for the first time are combined and the real-time high-speed transmission of PAM-4 signal based on the LED array light source in 12 m underwater channel at 100 Mbps rate is implemented,which effectively improves the throughput of the UWOC system with a high-power commercial LED light source.In light of diversity gain,the system employs the diversity of repeated coding scheme to receive two identical non-return-to-zero on-off keying(NRZ-OOK)signals,which can compensate the fading or flickering sublinks in real time under the bubble-like simulated turbulence condition,and has high robustness.To our knowledge,this is the first instance of a high rate and long-distance implementation of a turbulence-resistant real-time MIMO miniaturized UWOC system based on FPGA and high-power LED arrays.With spatial diversity or spatial multiplexing capabilities,its low cost,integrity,and high robustness provide the system with important practical prospects.
基金supported by a Three-year action plan for Shanghai(ZY(2021-2023)-0211)National Natural Science Foundation of China(No.81973730)+4 种基金Local Colleges Faculty Constitution of Shanghai MSTC 2022(No.22010504300)Shanghai Collaborative Innovation Center for Chronic Disease Prevention and Health Services(2021 Science and Technology 02-37)China Postdoctoral Science Foundation,No.72 General Fund,2022(No.2022M722164)Shanghai 2023"Science and Technology Innovation Action Plan"Qi Ming Xing Cultivation(Yang Fan Project,No.23YF1447700)Shanghai Health Commission for Traditional Chinese Medicine Research(No.2022QN014).
文摘Non-alcoholic fatty liver disease(NAFLD)is a liver condition that is widely prevalent across the world.A considerable number of people with NAFLD have the potential to progress to a more severe form of the condition known as nonalcoholic steatohepatitis(NASH),accompanied by bridging fibrosis.This advancement is more likely if the patient has metabolic risk factors such as obesity or type 2 diabetes that deteriorate over time.Additionally,even slight inflammation or fibrosis in NAFLD can significantly increase the likelihood of progression compared to steatosis alone.This underscores the importance of revising the present methods of monitoring NAFLD patients to ensure early detection and effective management of the disease.
文摘The optimal guidance problem for an interceptor against a ballistic missile with active defense is investigated in this paper.A class of optimal guidance schemes are proposed based on linear quadratic differential game method and numerical solution of Riccati differential equation.By choosing proper parameters, the proposed guidance schemes are able to drive the interceptor to the target and away from the defender simultaneously.Additionally, fuel cost, control saturation,chattering phenomenon and parameters selection were taken into account.Satisfaction of the proposed guidance schemes of the saddle point condition is proven theoretically.Finally, nonlinear numerical examples are included to demonstrate the effectiveness and performance of the developed guidance approaches.Comparison of control performance between different guidance schemes are presented and analysis.
基金This study is supported by the National Natural Science Foundation of China(No.816220108030)the Evidence-based Capacity Building Project for Basic Traditional Chinese Medicine-Specialized Diseases(No.2019XZZX-XH012)Shanghai Three-year Action Planfor Accelerating the Development of Traditional Chinese Medicine(ZY(2018-2020)-CCCX-2002-01).
文摘Lingguizhugan Decoction(LGZG)has been investigated in basic studies,with satisfactory effects on insulin resistance in non-alcoholic fatty liver disease(NAFLD).This translational approach aimed to explore the effect and underlying mechanism of LGZG in clinical setting.A randomized,double-blinded,placebo-controlled trial was performed.A total of 243 eligible participants with NAFLD were equally allocated to receive LGZG(two groups:standard dose and low dose)or placebo for 12 weeks on the basis of lifestyle modifications.The primary efficacy variable was homeostasis model assessment of insulin resistance(HOMA-IR).Analyses were performed in two populations in accordance with body mass index(BMI;overweight/obese,BMI 24 kg/m^(2);lean,BMI<24 kg/m^(2)).For overweight/obese participants,low-dose LGZG significantly decreased their HOMA-IR level compared with placebo(0.19(1.47)versus 0.08(1.99),P=0.038).For lean subjects,neither dose of LGZG showed a superior effect compared with placebo.Methylated DNA immunoprecipitation sequencing and real-time qPCR found that the DNA N6-methyladenine modification levels of protein phosphatase 1 regulatory subunit 3A(PPP1R3A)and autophagy related 3(ATG3)significantly increased after LGZG intervention in overweight/obese population.Low-dose LGZG effectively improved insulin resistance in overweight/obese subjects with NAFLD.The underlying mechanism may be related to the regulation of DNA N6-methyladenine modification of PPP1R3A and ATG3.Lean subjects may not be a targeted population for LGZG.
基金the National Key Research and Development Program of China(No.2020YFB0311300ZL)the National Natural Science Foundation of China(No.52071343)。
文摘The selective laser melting(SLM)with subsequent cold rolling and annealing is used to produce high-density lattice defects and grain refinement in the CoCrNi medium-entropy alloys(MEAs).The superior comprehensive mechanical properties have been achieved in the as-SLMed CoCrNi alloy after rolling and annealing.The as-SLMed alloys delivered the yield strength of 693.4 MPa,the ultimate tensile strength of 912.7 MPa and the fracture strain of 54.4%.After rolling with 70%reduction in thickness and annealing at 700℃for 2 h.the yield strength,ultimate tensile strength and fracture strain reached 1161.6 MPa,1390.8 MPa and 31.5%,respectively.The exceptional strength-ductility synergy is mainly attributed to the refined hierarchical microstructures with coarsening grains at a level of 30μm and ultrafine grains at a level of 1μm,and the heritage of dislocation-formed sub-grains and other lattice defects.This investigation demonstrates that the SLM with subsequent rolling and annealing is beneficial to fabricate high strength and ductile MEAs with single face-centered cubic(fcc)structure.
基金This work was financially supported by the National Key Research and Development Program of China(No.2020YFB0311300ZL)the National Natural Science Foundation of China(No.52071343).
文摘The coarsening-grained single-phase face-centered cubic(fcc)medium-entropy alloys(MEAs)normally exhibit insufficient strength for some engineering applications.Here,superior mechanical properties with ultimate tensile strength of 1.6 GPa and fracture strain of 13.1%at ambient temperature have been achieved in a(CoCrNi)_(94)Ti_(3)Al_(3)MEA by carefully architecting the multi-scale heterogeneous structures.Electron microscopy characterization indicates that the superior mechanical properties mainly originated from the favorable heterogeneous fcc matrix(1-40μm)and the coherent sphericalγ’precipitates(10-100 nm),together with a high number density of crystalline defects(2-10 nm),including dislocations,small stacking faults,Lomer-Cottrell locks,and ultrafine deformation twins.
基金financially supported by the National Key Research and Development Program of China (No.2020YFB0311300ZL)the National Natural Science Foundation of China (No. 52071343)。
文摘A novel Al-5 Mg2 Si-2 Mg alloy was processed by selective laser melting(SLM) to understand its representative features of microstructural evolution and mechanical properties during additive manufacturing(AM). The as-SLM fabricated Al-5 Mg_(2) Si-2 Mg alloy is found to deliver much less hot cracks and other defects. Meanwhile, excellent mechanical property is also achieved, i.e. 452 ± 11 MPa for ultimate tensile strength, 295 ± 14 MPa for yield strength, and 9.3 ± 2.5% for elongation. Clearly, these mechanical properties are better than that obtained by high pressure die casting(HPDC), and better than some other alloys obtained by SLM. The as-SLM fabricated Al-5 Mg_(2) Si-2 Mg alloy is featured by the significantly refined microstructures in the compact primary α-Al, the divorced Mg_(2) Si eutectic networks distributing atα-Al grain boundaries, and some α-Al Fe Mn Si phase in association with eutectic Mg_(2) Si phase. The high strength and ductility of the alloy are attributed to its unique features including(a) the reduced solidification range,(b) the possible increase of the eutectic level in the microstructure, and(c) the shift of eutectic point and the maximum solubility point of Mg2 Si in Al matrix.
基金sponsored by the "Shu Guang" project supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission (15SG39, China)the Shanghai Pujiang Program (16PJD044, China)+1 种基金National Natural Science Foundation of China (81573814)the science and technology project supported by the Science and Technology Commission of Huangpu District (ZYKC201603008, China)
文摘Pharmaceutical cocrystals are a promising technology that can be used to improve the solubility of poor aqueous compounds. The objective of this study was to systematically investigate the solubility of myricetin(MYR) cocrystals, including their kinetic solubility, thermodynamic solubility, and intrinsic dissolution rate(IDR). The effects of pH, surfactant, ion concentration, and coformers on the cocrystal solubility were evaluated. Furthermore, single crystal structures of MYR, myricetin–isonicotinamide(MYR–INM) and myricetin–caffeine(MYR–CAF) cocrystals were analyzed to discuss the possible reasons for the enhancement of cocrystal solubility from the perspective of the spatial structure.The results indicated that the kinetic solubility of MYR cocrystals was modulated by pH and cocrystal coformer(CCF) ionization in buffer solution, while it primarily depended on the CCF solubility in pure water. In addition, the solubility of MYR cocrystals was increased in a concentration dependent fashion by the surfactant or ion concentration. The thermodynamic solubility of MYR–INM(1:3) cocrystals decreased with the increases of the pH value of the dissolution media. The IDR of MYR cocrystals was faster than that of MYR in the same medium and extremely fast in pH 4.5 buffer. The improved solubility of MYR cocrystals was probably related to the alternate arrangements of MYR and INM/CAF molecules and increased intermolecular distance. The present study provides some references to investigate the solubility behavior of pharmaceutical cocrystals.
