This paper introduced supersonic expansion liquefaction technology into the field of hydrogen liquefaction.The mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was established.The...This paper introduced supersonic expansion liquefaction technology into the field of hydrogen liquefaction.The mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was established.The supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions were investigated.The simulation results show that the droplet number rises rapidly from 0 at the nozzle throat as the inlet temperature increases,and the maximum droplet number generated is 1.339×10^(18)kg^(-1)at inlet temperature of 36.0 K.When hydrogen nucleation occurs,the droplet radius increases significantly and shows a positive correlation with the increase in the inlet temperature,and the maximum droplet radii are 6.667×10^(-8)m,1.043×10^(-7)m,and 1.099×10^(-7)m when the inlet temperature is 36.0 K,36.5 K,and 37.0 K,respectively.The maximum nucleation rate decreases with increasing inlet temperature,and the nucleation region of the Laval nozzle becomes wider.The liquefaction efficiency can be effectively improved by lowering the inlet temperature.This is because a lower inlet temperature provides more subcooling,which allows the hydrogen to reach the thermodynamic conditions required for large-scale condensation more quickly.展开更多
Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as hydrolys...Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as hydrolysis.Among inorganic materials,the high hydrogen capacity for hydrolysis of MgH_(2)(15.2 wt%)makes it a promising material for hydrogen production via hydrolysis.However,the dense Mg(OH)_(2) passivation layer will block the reaction between MgH_(2) and the solution,resulting in low hydrogen yield and sluggish hydrolysis kinetics.In this work,the hydrogenyield and hydrogen generation rate of MgH_(2) are considerably enhanced by adding Ti-Zr-Fe-Mn-Cr-V high-entropy alloys(HEAs) for the first time.In particular.the MgH_(2)-3 wt% TiZrFe_(1.5)MnCrV_(0.5)(labelled as MgH_(2)-3 wt% Fe_(1.5)) composite releases 1526.70 mL/g H_(2) within 5 min at 40℃,and the final hydrolysis conversion rate reaches 95.62% within 10 min.The mean hydrogen generation rate of the MgH_(2)-3 wt% Fe_(1.5) composite is 289.16 mL/g/min,which is 2.38 times faster than that of pure MgH_(2).Meanwhile,the activation energy of the MgH_(2)-3 wt% Fe_(1.5) composite is calculated to be 12.53 kJ/mol. The density functional theory(DFT) calculation reveals that the addition of HEAs weakens the Mg-H bonds and accelerates the electron transfer between MgH_(2) and HEAs,Combined with the cocktail effect of HEAs as well as the formation of more interfaces and micro protocells,the hydrolysis performance of MgH_(2) is considerably improved.This work provides an appealing prospect for real-time hydrogen supply and offers a new effective strategy for improving the hydrolysis performance of MgH_(2).展开更多
The scale and complexity of big data are growing continuously,posing severe challenges to traditional data processing methods,especially in the field of clustering analysis.To address this issue,this paper introduces ...The scale and complexity of big data are growing continuously,posing severe challenges to traditional data processing methods,especially in the field of clustering analysis.To address this issue,this paper introduces a new method named Big Data Tensor Multi-Cluster Distributed Incremental Update(BDTMCDIncreUpdate),which combines distributed computing,storage technology,and incremental update techniques to provide an efficient and effective means for clustering analysis.Firstly,the original dataset is divided into multiple subblocks,and distributed computing resources are utilized to process the sub-blocks in parallel,enhancing efficiency.Then,initial clustering is performed on each sub-block using tensor-based multi-clustering techniques to obtain preliminary results.When new data arrives,incremental update technology is employed to update the core tensor and factor matrix,ensuring that the clustering model can adapt to changes in data.Finally,by combining the updated core tensor and factor matrix with historical computational results,refined clustering results are obtained,achieving real-time adaptation to dynamic data.Through experimental simulation on the Aminer dataset,the BDTMCDIncreUpdate method has demonstrated outstanding performance in terms of accuracy(ACC)and normalized mutual information(NMI)metrics,achieving an accuracy rate of 90%and an NMI score of 0.85,which outperforms existing methods such as TClusInitUpdate and TKLClusUpdate in most scenarios.Therefore,the BDTMCDIncreUpdate method offers an innovative solution to the field of big data analysis,integrating distributed computing,incremental updates,and tensor-based multi-clustering techniques.It not only improves the efficiency and scalability in processing large-scale high-dimensional datasets but also has been validated for its effectiveness and accuracy through experiments.This method shows great potential in real-world applications where dynamic data growth is common,and it is of significant importance for advancing the development of data analysis technology.展开更多
In this work,we present a reconfigurable data glove design to capture different modes of human hand-object interactions,which are critical in training embodied artificial intelligence(AI)agents for fine manipulation t...In this work,we present a reconfigurable data glove design to capture different modes of human hand-object interactions,which are critical in training embodied artificial intelligence(AI)agents for fine manipulation tasks.To achieve various downstream tasks with distinct features,our reconfigurable data glove operates in three modes sharing a unified backbone design that reconstructs hand gestures in real time.In the tactile-sensing mode,the glove system aggregates manipulation force via customized force sensors made from a soft and thin piezoresistive material;this design minimizes interference during complex hand movements.The virtual reality(VR)mode enables real-time interaction in a physically plausible fashion:A caging-based approach is devised to determine stable grasps by detecting collision events.Leveraging a state-of-the-art finite element method,the simulation mode collects data on fine-grained four-dimensionalmanipulation events comprising hand and object motions in three-dimensional space and how the object's physical properties(e.g.,stress and energy)change in accordance with manipulation over time.Notably,the glove system presented here is the first to use high-fidelity simulation to investigate the unobservable physical and causal factors behind manipulation actions.In a series of experiments,we characterize our data glove in terms of individual sensors and the overall system.More specifically,we evaluate the system's three modes by①recording hand gestures and associated forces,②improving manipulation fluency in VR,and③producing realistic simulation effects of various tool uses,respectively.Based on these three modes,our reconfigurable data glove collects and reconstructs fine-grained human grasp data in both physical and virtual environments,thereby opening up new avenues for the learning of manipulation skills for embodied AI agents.展开更多
Lead halide hybrid perovskites(LHP)have emerged as one of the most promising photovoltaic materials for their remarkable solar energy conversion ability.The transportation of the photoinduced carriers in LHP could scr...Lead halide hybrid perovskites(LHP)have emerged as one of the most promising photovoltaic materials for their remarkable solar energy conversion ability.The transportation of the photoinduced carriers in LHP could screen the defect recombination with the help of the large polaron formation.However,the physical insight of the relationship between the superior optical-electronic performance of perovskite and its polaron dynamics related to the electron-lattice strong coupling induced by the substitution engineering is still lack of investigation.Here,the bandgap modulated thin films ofα-FAPbI_(3)with different element substitution is investigated by the time resolved Terahertz spectroscopy.We find the polaron recombination dynamics could be prolonged in LHP with a relatively smaller bandgap,even though the formation of polaron will not be affected apparently.Intuitively,the large polaron mobility in(FAPb I_(3))0.95(MAPbI_(3))0.05thin film is~30%larger than that in(FAPb I_(3))0.85(MAPbBr_(3))0.15.The larger mobility in(FAPb I_(3))0.95(MAPb I_(3))0.05could be assigned to the slowing down of the carrier scattering time.Therefore,the physical origin of the higher carrier mobility in the(FAPb I_(3))0.95(MAPbI_(3))0.05should be related with the lattice distortion and enhanced electron–phonon coupling induced by the substitution.In addition,(FAPbI_(3))0.95(MAPbI_(3))0.05will lose fewer active carriers during the polaron cooling process than that in(FAPb I_(3))0.85(MAPbBr_(3)),indicating lower thermal dissipation in(FAPbI_(3))0.95(MAPbI_(3))0.05.Our results suggest that besides the smaller bandgap,the higher polaron mobility improved by the substitution engineering inα-FAPbI_(3)can also be an important factor for the high PCE of the black phaseα-FAPbI_(3)based solar cell devices.展开更多
With the rapid development of urban road traffic and the increasing number of vehicles,how to alleviate traffic congestion is one of the hot issues that need to be urgently addressed in building smart cities.Therefore...With the rapid development of urban road traffic and the increasing number of vehicles,how to alleviate traffic congestion is one of the hot issues that need to be urgently addressed in building smart cities.Therefore,in this paper,a nonlinear multi-objective optimization model of urban intersection signal timing based on a Genetic Algorithm was constructed.Specifically,a typical urban intersection was selected as the research object,and drivers’acceleration habits were taken into account.What’s more,the shortest average delay time,the least average number of stops,and the maximum capacity of the intersection were regarded as the optimization objectives.The optimization results show that compared with the Webster method when the vehicle speed is 60 km/h and the acceleration is 2.5 m/s^(2),the signal intersection timing scheme based on the proposed Genetic Algorithm multi-objective optimization reduces the intersection signal cycle time by 14.6%,the average vehicle delay time by 12.9%,the capacity by 16.2%,and the average number of vehicles stop by 0.4%.To verify the simulation results,the authors imported the optimized timing scheme into the constructed Simulation of the Urban Mobility model.The experimental results show that the authors optimized timing scheme is superior to Webster’s in terms of vehicle average loss time reduction,carbon monoxide emission,particulate matter emission,and vehicle fuel consumption.The research in this paper provides a basis for Genetic algorithms in traffic signal control.展开更多
Lactose plays a crucial role in the growth performance of pigs at weaning because it is a palatable and easily digestible energy source that eases the transition from milk to solid feed.However,the digestibility of la...Lactose plays a crucial role in the growth performance of pigs at weaning because it is a palatable and easily digestible energy source that eases the transition from milk to solid feed.However,the digestibility of lactose declines after weaning due to a reduction in endogenous lactase activity in piglets.As a result,some lactose may be fermented in the gastrointestinal tract of pigs.Fermentation of lactose by intestinal microbiota yields lactic acid and volatile fatty acids,which may positively regulate the intestinal environment and microbiome,resulting in improved gastrointestinal health of weanling pigs.We hypothesize that the prebiotic effect of lactose may play a larger role in weanling pig nutrition as the global feed industry strives to reduce antibiotic usage and pharmacological levels of zinc oxide and supra-nutritional levels of copper.Evidence presented in this review indicates that high dietary lactose improves growth performance of piglets,as well as the growth of beneficial bacteria,particularly Lactobacillus,with the positive effects being more pronounced in the first 2 weeks after weaning.However,the risk of post-weaning diarrhea may increase as pigs get older due to reduced lactase activity,high dietary lactose concentrations,and larger feed intakes,all of which may lead to excessive lactose fermentation in the intestine of the pig.Therefore,dietary lactose levels exert different effects on growth performance and gastrointestinal physiological functions in different feeding phases of weanling pigs.However,no formal recommendation of lactose for weanling pigs has been reported.A meta-analysis approach was used to determine that diets fed to swine should include 20%,15%,and 0 lactose from d 0-7,d 7-14,and d 14-35 post-weaning,respectively.However,sustainable swine production demands that economics must also be taken into account as lactose and lactose containing ingredients are expensive.Therefore,alternatives to lactose,so called“lactose equivalents”have also been studied in an effort to decrease feed cost while maintaining piglet performance with lower dietary lactose inclusions.In summary,the present review investigated dose-response effects of dietary lactose supplementation to exert positive responses and begin to elucidate its mechanisms of action in postweaning pig diets.The results may help to replace some or all lactose in the diet of weanling pigs,while improving production economics given the high cost of lactose and availability in some swine production markets.展开更多
Deep learning for topology optimization has been extensively studied to reduce the cost of calculation in recent years.However,the loss function of the above method is mainly based on pixel-wise errors from the image ...Deep learning for topology optimization has been extensively studied to reduce the cost of calculation in recent years.However,the loss function of the above method is mainly based on pixel-wise errors from the image perspective,which cannot embed the physical knowledge of topology optimization.Therefore,this paper presents an improved deep learning model to alleviate the above difficulty effectively.The feature pyramid network(FPN),a kind of deep learning model,is trained to learn the inherent physical law of topology optimization itself,of which the loss function is composed of pixel-wise errors and physical constraints.Since the calculation of physical constraints requires finite element analysis(FEA)with high calculating costs,the strategy of adjusting the time when physical constraints are added is proposed to achieve the balance between the training cost and the training effect.Then,two classical topology optimization problems are investigated to verify the effectiveness of the proposed method.The results show that the developed model using a small number of samples can quickly obtain the optimization structure without any iteration,which has not only high pixel-wise accuracy but also good physical performance.展开更多
Metal and amino acid(AA),as two kinds of entities,have been widely involved in biomaterials and nanomedicines.Recently,the marriage of them has developed new nanoformulations,amino acid-metal coordinated nanomaterials...Metal and amino acid(AA),as two kinds of entities,have been widely involved in biomaterials and nanomedicines.Recently,the marriage of them has developed new nanoformulations,amino acid-metal coordinated nanomaterials(AMCNs),which show great biomedical application potential in cancer therapy,antibacterial applications,biomedical imaging,etc.With the respective characteristics of metal and AA with rich biological and chemical properties,AMCNs can not only act as drug carriers with specific tumor targeting ability,but also realize synergistic therapy and imaging-guided therapy.Although the design and synthesis of amino acid-metal coordinated nanomaterials have been in-depth investigated,there are few systematic reviews on their biomedical application.In this review,we give a comprehensive summary of recent progresses in the design,fabrication,and biomedical applications of AMCNs.We also propose the future outlooks and challenges in aforementioned field.We expect that this review would contribute some inspiration for future research and development for amino acid metal coordinated nanomaterials.展开更多
The exhaust volute is a device that can change the exhaust direction of the ship’s gas turbine to reduce the flow loss of the high-temperature and high-speed turbine exhaust gas in the box-type exhaust volute,thereby...The exhaust volute is a device that can change the exhaust direction of the ship’s gas turbine to reduce the flow loss of the high-temperature and high-speed turbine exhaust gas in the box-type exhaust volute,thereby improving its power output performance.This paper first investigates the internal flow field characteristics of the exhaust volute via numerical simulation and reveals the main source of the internal resistance loss of the volute.On the premise of not affecting the installation size of the volute and matching it with other components in the cabin,the design scheme of volute bottom shunt and volute chamfer are then optimized in accordance with the flow characteristics inside the volute.Numerical simulation results show that the partial flow structure at the bottom of the volute can effectively improve the low-velocity region and the vortex flow at the bottom of the volute,and the chamfered angle scheme can control the regular expansion and compression of the airflow.When the volute adopts the appropriate chamfer angle and the bottom split-flow structure,the total pressure loss can be reduced by 19.6%,and the static pressure recovery coefficient can be increased by 42.05%.展开更多
Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic...Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field.The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from300 K to 150 K.The AHE scaling law in Mn_(4)N films is influenced by the temperature-dependent magnetization,carrier concentration and interfacial scattering.Different scaling laws are used to distinguish the various contributions of AHE mechanisms.The scaling exponentγ>2 for the conventional scaling in Mn_(4)N films could be attributed to the residual resistivityρ_(xx0).The longitudinal conductivityσ_(xx)falls into the dirty regime.The scaling ofρ_(AH)=αρ_(xx0)+bρ_(xx)~nis used to separate out the temperature-independentρ_(xx0)from extrinsic contribution.Moreover,the relationship betweenρ_(AH)and pxx is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE,which demonstrates that the dominant mechanism of AHE in the Mn4 N films can be ascribed to the competition between skew scattering,side jump and the intrinsic mechanisms.展开更多
Based on the close relationship between MGBA and PSCI,one PSCI related case is reported,and it is emphasized to improve clinicians'understanding of MGBA theory in the treatment of PSCI,thereby providing new ideas ...Based on the close relationship between MGBA and PSCI,one PSCI related case is reported,and it is emphasized to improve clinicians'understanding of MGBA theory in the treatment of PSCI,thereby providing new ideas for exploring pathogenesis and treatment of PSCI.展开更多
As a common chronic disease of the elderly,diabetes endangers both physical and mental health of the elderly.Diarrhea is a common complication of diabetes and causes great inconvenience to patients’daily life.Profess...As a common chronic disease of the elderly,diabetes endangers both physical and mental health of the elderly.Diarrhea is a common complication of diabetes and causes great inconvenience to patients’daily life.Professor Zhou Lingyun from Chief Physician,Department of Geriatrics,Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine has been engaged in clinical practice for many years and is good at treating miscellaneous diseases in geriatric internal medicine.She has unique thinking and experience in the diagnosis and treatment of diabetic diarrhea.Professor Zhou Lingyun believed that the pathogenesis of diabetic diarrhea in the elderly is the deficiency of spleen and stomach qi and dampness.She is good at using Modified Sijunzi Decoction to nourish qi,invigorate the spleen and dispel dampness,so as to treat diabetic diarrhea.This paper introduced and analyzed a classic case of Professor Zhou Lingyun’s treatment of diabetic diarrhea in the elderly.展开更多
Dendrocalamus brandisii(Munro)Kurz is a sympodial bamboo species with inimitable taste and flavorful shoots.Its rapid growth and use as high-quality material make this bamboo species highly valued for both food proces...Dendrocalamus brandisii(Munro)Kurz is a sympodial bamboo species with inimitable taste and flavorful shoots.Its rapid growth and use as high-quality material make this bamboo species highly valued for both food processing and wood applications.However,genome information for D.brandisii is lacking,primarily due to its polyploidy and large genome size.Here,we assembled a high-quality genome for hexaploid D.brandisii,which comprises 70chromosomes with a total size of 2,756 Mb,using long-read Hi Fi sequencing.Furthermore,we accurately separated the genome into its three constituent subgenomes.We used Oxford Nanopore Technologies long reads to construct a transcriptomic dataset covering 15 tissues for gene annotation to complement our genome assembly,revealing differential gene expression and post-transcriptional regulation.By integrating metabolome analysis,we unveiled that well-balanced lignin formation,as well as abundant flavonoid and fructose contents,contribute to the superior quality of D.brandisii shoots.Integrating genomic,transcriptomic,and metabolomic datasets provided a solid foundation for enhancing bamboo shoot quality and developing efficient gene-editing techniques.This study should facilitate research on D.brandisii and enhance its use as a food source and wood material by providing crucial genomic resources.展开更多
During the construction of an offshore wind farm(OWF),the capital cost of the collector cable system accounts for a large proportion of the total cost.Consequently,the optimal design of the collector system topology(C...During the construction of an offshore wind farm(OWF),the capital cost of the collector cable system accounts for a large proportion of the total cost.Consequently,the optimal design of the collector system topology(CST)is one of the most crucial tasks in OWF planning.However,for a large-scale OWF,the optimal design of CST is a complex integer programming problem with high-dimension variables and various constraints.Therefore,it is difficult to acquire a high-quality optimal design scheme.To address this issue,this paper proposes a new grouping-based optimal design of CST for a large-scale OWF.First,all the wind turbines are divided into multiple groups according to their geographical locations and the maximum allowed connected wind turbines by each cable.This not only reduces the optimization dimension and difficulty,but also effectively satisfies the‘no cross’constraint by putting the geographically closed wind turbines into the same group.Secondly,the electrical topology among different wind turbines in each group is initially generated by an improved dynamic minimum spanning tree(DMST).The division groups of the OWF are then adjusted to further reduce the capital cost by improved simulated annealing.To verify the proposed technique,comparison case studies are carried out with five algorithms on two different OWF.展开更多
The scarcity of proxies and calibration models for quantitatively reconstructing millennial timescale seasonal temperature tremendously constraints our understanding of the Holocene thermal variation and its driven me...The scarcity of proxies and calibration models for quantitatively reconstructing millennial timescale seasonal temperature tremendously constraints our understanding of the Holocene thermal variation and its driven mechanisms.Here,we established two global warm-season temperature models by applying deep learning neural network analysis to the branched tetraether membrane lipids originating from surface soil and lacustrine sediment bacteria.We utilized these optimal models in global well-dated lacustrine,peatland,and loess profiles covering the Holocene.All reconstructions of warm-season temperatures,consistent with climate model simulations,indicate cooling trends since the early Holocene,primarily induced by decreased solar radiation in the Northern Hemisphere due to the precession peak at the early.We further demonstrated that the membrane lipids can effectively enhance the future millennial seasonal temperature research,including winter temperatures,without being restricted by geographical location and sedimentary carrier.展开更多
The pneumonia caused by novel coronavirus SARS-CoV-2 infection in early December 2019,which was later named coronavirus disease 2019(COVID-19)by the World Health Organization(WHO),rapidly spread across the world.China...The pneumonia caused by novel coronavirus SARS-CoV-2 infection in early December 2019,which was later named coronavirus disease 2019(COVID-19)by the World Health Organization(WHO),rapidly spread across the world.China has made extraordinary efforts to this unprecedented pandemic,put its response and control at a very high level of infectious disease management(Category B but with measures for Category A),given top priority to the people and their lives,and balanced the pandemic control and socio-economic development.After more than three years’fighting against this disease,China downgraded the management of COVID-19 to Category B infectious disease on January 8,2023 and the WHO declared the end of public health emergency on May 5,2023.However,the ending of pandemic does not mean that the disease is no longer a health threat.Experiences against COVID-19 from China and the whole world should be learned to prepare well for the future public health emergencies.This article gives a systematic review of the trajectory of COVID-19 development in China,summarizes the critical policy arrangements and provides evidence for the adjustment during policy making process,so as to share experiences with international community and contribute to the global health for all humanity.展开更多
基金supported by the National Natural Science Foundation of China(U2241257)the Postdoctoral Science Foundation of China(2022M723497)。
文摘This paper introduced supersonic expansion liquefaction technology into the field of hydrogen liquefaction.The mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was established.The supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions were investigated.The simulation results show that the droplet number rises rapidly from 0 at the nozzle throat as the inlet temperature increases,and the maximum droplet number generated is 1.339×10^(18)kg^(-1)at inlet temperature of 36.0 K.When hydrogen nucleation occurs,the droplet radius increases significantly and shows a positive correlation with the increase in the inlet temperature,and the maximum droplet radii are 6.667×10^(-8)m,1.043×10^(-7)m,and 1.099×10^(-7)m when the inlet temperature is 36.0 K,36.5 K,and 37.0 K,respectively.The maximum nucleation rate decreases with increasing inlet temperature,and the nucleation region of the Laval nozzle becomes wider.The liquefaction efficiency can be effectively improved by lowering the inlet temperature.This is because a lower inlet temperature provides more subcooling,which allows the hydrogen to reach the thermodynamic conditions required for large-scale condensation more quickly.
基金financed by the National Key Research and Development Program of China [2022YFB3803703]the National Natural Science Foundation of China [52071141, 52271212, 52201250, 51771056]the Interdisciplinary Innovation Program of North China Electric Power University [XM2112355]。
文摘Hydrogen energy is one of the ideal energy alternatives and the upstream of the hydrogen industry chain is hydrogen production,which can be achieved via the reaction of inorganic materials with water,known as hydrolysis.Among inorganic materials,the high hydrogen capacity for hydrolysis of MgH_(2)(15.2 wt%)makes it a promising material for hydrogen production via hydrolysis.However,the dense Mg(OH)_(2) passivation layer will block the reaction between MgH_(2) and the solution,resulting in low hydrogen yield and sluggish hydrolysis kinetics.In this work,the hydrogenyield and hydrogen generation rate of MgH_(2) are considerably enhanced by adding Ti-Zr-Fe-Mn-Cr-V high-entropy alloys(HEAs) for the first time.In particular.the MgH_(2)-3 wt% TiZrFe_(1.5)MnCrV_(0.5)(labelled as MgH_(2)-3 wt% Fe_(1.5)) composite releases 1526.70 mL/g H_(2) within 5 min at 40℃,and the final hydrolysis conversion rate reaches 95.62% within 10 min.The mean hydrogen generation rate of the MgH_(2)-3 wt% Fe_(1.5) composite is 289.16 mL/g/min,which is 2.38 times faster than that of pure MgH_(2).Meanwhile,the activation energy of the MgH_(2)-3 wt% Fe_(1.5) composite is calculated to be 12.53 kJ/mol. The density functional theory(DFT) calculation reveals that the addition of HEAs weakens the Mg-H bonds and accelerates the electron transfer between MgH_(2) and HEAs,Combined with the cocktail effect of HEAs as well as the formation of more interfaces and micro protocells,the hydrolysis performance of MgH_(2) is considerably improved.This work provides an appealing prospect for real-time hydrogen supply and offers a new effective strategy for improving the hydrolysis performance of MgH_(2).
基金sponsored by the National Natural Science Foundation of China(Nos.61972208,62102194 and 62102196)National Natural Science Foundation of China(Youth Project)(No.62302237)+3 种基金Six Talent Peaks Project of Jiangsu Province(No.RJFW-111),China Postdoctoral Science Foundation Project(No.2018M640509)Postgraduate Research and Practice Innovation Program of Jiangsu Province(Nos.KYCX22_1019,KYCX23_1087,KYCX22_1027,KYCX23_1087,SJCX24_0339 and SJCX24_0346)Innovative Training Program for College Students of Nanjing University of Posts and Telecommunications(No.XZD2019116)Nanjing University of Posts and Telecommunications College Students Innovation Training Program(Nos.XZD2019116,XYB2019331).
文摘The scale and complexity of big data are growing continuously,posing severe challenges to traditional data processing methods,especially in the field of clustering analysis.To address this issue,this paper introduces a new method named Big Data Tensor Multi-Cluster Distributed Incremental Update(BDTMCDIncreUpdate),which combines distributed computing,storage technology,and incremental update techniques to provide an efficient and effective means for clustering analysis.Firstly,the original dataset is divided into multiple subblocks,and distributed computing resources are utilized to process the sub-blocks in parallel,enhancing efficiency.Then,initial clustering is performed on each sub-block using tensor-based multi-clustering techniques to obtain preliminary results.When new data arrives,incremental update technology is employed to update the core tensor and factor matrix,ensuring that the clustering model can adapt to changes in data.Finally,by combining the updated core tensor and factor matrix with historical computational results,refined clustering results are obtained,achieving real-time adaptation to dynamic data.Through experimental simulation on the Aminer dataset,the BDTMCDIncreUpdate method has demonstrated outstanding performance in terms of accuracy(ACC)and normalized mutual information(NMI)metrics,achieving an accuracy rate of 90%and an NMI score of 0.85,which outperforms existing methods such as TClusInitUpdate and TKLClusUpdate in most scenarios.Therefore,the BDTMCDIncreUpdate method offers an innovative solution to the field of big data analysis,integrating distributed computing,incremental updates,and tensor-based multi-clustering techniques.It not only improves the efficiency and scalability in processing large-scale high-dimensional datasets but also has been validated for its effectiveness and accuracy through experiments.This method shows great potential in real-world applications where dynamic data growth is common,and it is of significant importance for advancing the development of data analysis technology.
基金the National Key Research and Development Program of China(2021ZD0150200)the Beijing Nova Program.
文摘In this work,we present a reconfigurable data glove design to capture different modes of human hand-object interactions,which are critical in training embodied artificial intelligence(AI)agents for fine manipulation tasks.To achieve various downstream tasks with distinct features,our reconfigurable data glove operates in three modes sharing a unified backbone design that reconstructs hand gestures in real time.In the tactile-sensing mode,the glove system aggregates manipulation force via customized force sensors made from a soft and thin piezoresistive material;this design minimizes interference during complex hand movements.The virtual reality(VR)mode enables real-time interaction in a physically plausible fashion:A caging-based approach is devised to determine stable grasps by detecting collision events.Leveraging a state-of-the-art finite element method,the simulation mode collects data on fine-grained four-dimensionalmanipulation events comprising hand and object motions in three-dimensional space and how the object's physical properties(e.g.,stress and energy)change in accordance with manipulation over time.Notably,the glove system presented here is the first to use high-fidelity simulation to investigate the unobservable physical and causal factors behind manipulation actions.In a series of experiments,we characterize our data glove in terms of individual sensors and the overall system.More specifically,we evaluate the system's three modes by①recording hand gestures and associated forces,②improving manipulation fluency in VR,and③producing realistic simulation effects of various tool uses,respectively.Based on these three modes,our reconfigurable data glove collects and reconstructs fine-grained human grasp data in both physical and virtual environments,thereby opening up new avenues for the learning of manipulation skills for embodied AI agents.
基金supported by the National Natural Science Foundation of China(Nos.92050203,61905264,61925507,61875211,61674023,62005296,and 62105347)the National Key R&D Program of China 2017YFE0123700+1 种基金Shanghai Pilot Program for Basic Research(22JC1403200)the CAS Interdisciplinary Innovation Team。
文摘Lead halide hybrid perovskites(LHP)have emerged as one of the most promising photovoltaic materials for their remarkable solar energy conversion ability.The transportation of the photoinduced carriers in LHP could screen the defect recombination with the help of the large polaron formation.However,the physical insight of the relationship between the superior optical-electronic performance of perovskite and its polaron dynamics related to the electron-lattice strong coupling induced by the substitution engineering is still lack of investigation.Here,the bandgap modulated thin films ofα-FAPbI_(3)with different element substitution is investigated by the time resolved Terahertz spectroscopy.We find the polaron recombination dynamics could be prolonged in LHP with a relatively smaller bandgap,even though the formation of polaron will not be affected apparently.Intuitively,the large polaron mobility in(FAPb I_(3))0.95(MAPbI_(3))0.05thin film is~30%larger than that in(FAPb I_(3))0.85(MAPbBr_(3))0.15.The larger mobility in(FAPb I_(3))0.95(MAPb I_(3))0.05could be assigned to the slowing down of the carrier scattering time.Therefore,the physical origin of the higher carrier mobility in the(FAPb I_(3))0.95(MAPbI_(3))0.05should be related with the lattice distortion and enhanced electron–phonon coupling induced by the substitution.In addition,(FAPbI_(3))0.95(MAPbI_(3))0.05will lose fewer active carriers during the polaron cooling process than that in(FAPb I_(3))0.85(MAPbBr_(3)),indicating lower thermal dissipation in(FAPbI_(3))0.95(MAPbI_(3))0.05.Our results suggest that besides the smaller bandgap,the higher polaron mobility improved by the substitution engineering inα-FAPbI_(3)can also be an important factor for the high PCE of the black phaseα-FAPbI_(3)based solar cell devices.
基金supported by the joint NNSF&FDCT Project Number (0066/2019/AFJ)joint MOST&FDCT Project Number (0058/2019/AMJ),City University of Macao,Macao,China.
文摘With the rapid development of urban road traffic and the increasing number of vehicles,how to alleviate traffic congestion is one of the hot issues that need to be urgently addressed in building smart cities.Therefore,in this paper,a nonlinear multi-objective optimization model of urban intersection signal timing based on a Genetic Algorithm was constructed.Specifically,a typical urban intersection was selected as the research object,and drivers’acceleration habits were taken into account.What’s more,the shortest average delay time,the least average number of stops,and the maximum capacity of the intersection were regarded as the optimization objectives.The optimization results show that compared with the Webster method when the vehicle speed is 60 km/h and the acceleration is 2.5 m/s^(2),the signal intersection timing scheme based on the proposed Genetic Algorithm multi-objective optimization reduces the intersection signal cycle time by 14.6%,the average vehicle delay time by 12.9%,the capacity by 16.2%,and the average number of vehicles stop by 0.4%.To verify the simulation results,the authors imported the optimized timing scheme into the constructed Simulation of the Urban Mobility model.The experimental results show that the authors optimized timing scheme is superior to Webster’s in terms of vehicle average loss time reduction,carbon monoxide emission,particulate matter emission,and vehicle fuel consumption.The research in this paper provides a basis for Genetic algorithms in traffic signal control.
文摘Lactose plays a crucial role in the growth performance of pigs at weaning because it is a palatable and easily digestible energy source that eases the transition from milk to solid feed.However,the digestibility of lactose declines after weaning due to a reduction in endogenous lactase activity in piglets.As a result,some lactose may be fermented in the gastrointestinal tract of pigs.Fermentation of lactose by intestinal microbiota yields lactic acid and volatile fatty acids,which may positively regulate the intestinal environment and microbiome,resulting in improved gastrointestinal health of weanling pigs.We hypothesize that the prebiotic effect of lactose may play a larger role in weanling pig nutrition as the global feed industry strives to reduce antibiotic usage and pharmacological levels of zinc oxide and supra-nutritional levels of copper.Evidence presented in this review indicates that high dietary lactose improves growth performance of piglets,as well as the growth of beneficial bacteria,particularly Lactobacillus,with the positive effects being more pronounced in the first 2 weeks after weaning.However,the risk of post-weaning diarrhea may increase as pigs get older due to reduced lactase activity,high dietary lactose concentrations,and larger feed intakes,all of which may lead to excessive lactose fermentation in the intestine of the pig.Therefore,dietary lactose levels exert different effects on growth performance and gastrointestinal physiological functions in different feeding phases of weanling pigs.However,no formal recommendation of lactose for weanling pigs has been reported.A meta-analysis approach was used to determine that diets fed to swine should include 20%,15%,and 0 lactose from d 0-7,d 7-14,and d 14-35 post-weaning,respectively.However,sustainable swine production demands that economics must also be taken into account as lactose and lactose containing ingredients are expensive.Therefore,alternatives to lactose,so called“lactose equivalents”have also been studied in an effort to decrease feed cost while maintaining piglet performance with lower dietary lactose inclusions.In summary,the present review investigated dose-response effects of dietary lactose supplementation to exert positive responses and begin to elucidate its mechanisms of action in postweaning pig diets.The results may help to replace some or all lactose in the diet of weanling pigs,while improving production economics given the high cost of lactose and availability in some swine production markets.
基金This work was supported in part by National Natural Science Foundation of China under Grant Nos.11725211,52005505,and 62001502Post-graduate Scientific Research Innovation Project of Hunan Province under Grant No.CX20200023.
文摘Deep learning for topology optimization has been extensively studied to reduce the cost of calculation in recent years.However,the loss function of the above method is mainly based on pixel-wise errors from the image perspective,which cannot embed the physical knowledge of topology optimization.Therefore,this paper presents an improved deep learning model to alleviate the above difficulty effectively.The feature pyramid network(FPN),a kind of deep learning model,is trained to learn the inherent physical law of topology optimization itself,of which the loss function is composed of pixel-wise errors and physical constraints.Since the calculation of physical constraints requires finite element analysis(FEA)with high calculating costs,the strategy of adjusting the time when physical constraints are added is proposed to achieve the balance between the training cost and the training effect.Then,two classical topology optimization problems are investigated to verify the effectiveness of the proposed method.The results show that the developed model using a small number of samples can quickly obtain the optimization structure without any iteration,which has not only high pixel-wise accuracy but also good physical performance.
基金supported by the National Natural Science Foundation of China(82072065,81471784)the National Key Research and Development Program of the Minister of Science and Technology,China(2016YFA0202703)the National Youth Talent Support Program。
文摘Metal and amino acid(AA),as two kinds of entities,have been widely involved in biomaterials and nanomedicines.Recently,the marriage of them has developed new nanoformulations,amino acid-metal coordinated nanomaterials(AMCNs),which show great biomedical application potential in cancer therapy,antibacterial applications,biomedical imaging,etc.With the respective characteristics of metal and AA with rich biological and chemical properties,AMCNs can not only act as drug carriers with specific tumor targeting ability,but also realize synergistic therapy and imaging-guided therapy.Although the design and synthesis of amino acid-metal coordinated nanomaterials have been in-depth investigated,there are few systematic reviews on their biomedical application.In this review,we give a comprehensive summary of recent progresses in the design,fabrication,and biomedical applications of AMCNs.We also propose the future outlooks and challenges in aforementioned field.We expect that this review would contribute some inspiration for future research and development for amino acid metal coordinated nanomaterials.
基金Supported by the National Science and Technology Major Project(No.J2019-Ⅲ-0017).
文摘The exhaust volute is a device that can change the exhaust direction of the ship’s gas turbine to reduce the flow loss of the high-temperature and high-speed turbine exhaust gas in the box-type exhaust volute,thereby improving its power output performance.This paper first investigates the internal flow field characteristics of the exhaust volute via numerical simulation and reveals the main source of the internal resistance loss of the volute.On the premise of not affecting the installation size of the volute and matching it with other components in the cabin,the design scheme of volute bottom shunt and volute chamfer are then optimized in accordance with the flow characteristics inside the volute.Numerical simulation results show that the partial flow structure at the bottom of the volute can effectively improve the low-velocity region and the vortex flow at the bottom of the volute,and the chamfered angle scheme can control the regular expansion and compression of the airflow.When the volute adopts the appropriate chamfer angle and the bottom split-flow structure,the total pressure loss can be reduced by 19.6%,and the static pressure recovery coefficient can be increased by 42.05%.
基金supported by the National Natural Science Foundation of China(Grant Nos.51871161 and 52071233)。
文摘Epitaxial Mn_(4)N films with different thicknesses were fabricated by facing-target reactive sputtering and their anomalous Hall effect(AHE)is investigated systematically.The Hall resistivity shows a reversed magnetic hysteresis loop with the magnetic field.The magnitude of the anomalous Hall resistivity sharply decreases with decreasing temperature from300 K to 150 K.The AHE scaling law in Mn_(4)N films is influenced by the temperature-dependent magnetization,carrier concentration and interfacial scattering.Different scaling laws are used to distinguish the various contributions of AHE mechanisms.The scaling exponentγ>2 for the conventional scaling in Mn_(4)N films could be attributed to the residual resistivityρ_(xx0).The longitudinal conductivityσ_(xx)falls into the dirty regime.The scaling ofρ_(AH)=αρ_(xx0)+bρ_(xx)~nis used to separate out the temperature-independentρ_(xx0)from extrinsic contribution.Moreover,the relationship betweenρ_(AH)and pxx is fitted by the proper scaling to clarify the contributions from extrinsic and intrinsic mechanisms of AHE,which demonstrates that the dominant mechanism of AHE in the Mn4 N films can be ascribed to the competition between skew scattering,side jump and the intrinsic mechanisms.
文摘Based on the close relationship between MGBA and PSCI,one PSCI related case is reported,and it is emphasized to improve clinicians'understanding of MGBA theory in the treatment of PSCI,thereby providing new ideas for exploring pathogenesis and treatment of PSCI.
文摘As a common chronic disease of the elderly,diabetes endangers both physical and mental health of the elderly.Diarrhea is a common complication of diabetes and causes great inconvenience to patients’daily life.Professor Zhou Lingyun from Chief Physician,Department of Geriatrics,Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine has been engaged in clinical practice for many years and is good at treating miscellaneous diseases in geriatric internal medicine.She has unique thinking and experience in the diagnosis and treatment of diabetic diarrhea.Professor Zhou Lingyun believed that the pathogenesis of diabetic diarrhea in the elderly is the deficiency of spleen and stomach qi and dampness.She is good at using Modified Sijunzi Decoction to nourish qi,invigorate the spleen and dispel dampness,so as to treat diabetic diarrhea.This paper introduced and analyzed a classic case of Professor Zhou Lingyun’s treatment of diabetic diarrhea in the elderly.
基金supported by the National Key Research and Development Program of China(2021YFD2200505,2018YFD0600101)the National Natural Science Foundation of China(32071849)。
文摘Dendrocalamus brandisii(Munro)Kurz is a sympodial bamboo species with inimitable taste and flavorful shoots.Its rapid growth and use as high-quality material make this bamboo species highly valued for both food processing and wood applications.However,genome information for D.brandisii is lacking,primarily due to its polyploidy and large genome size.Here,we assembled a high-quality genome for hexaploid D.brandisii,which comprises 70chromosomes with a total size of 2,756 Mb,using long-read Hi Fi sequencing.Furthermore,we accurately separated the genome into its three constituent subgenomes.We used Oxford Nanopore Technologies long reads to construct a transcriptomic dataset covering 15 tissues for gene annotation to complement our genome assembly,revealing differential gene expression and post-transcriptional regulation.By integrating metabolome analysis,we unveiled that well-balanced lignin formation,as well as abundant flavonoid and fructose contents,contribute to the superior quality of D.brandisii shoots.Integrating genomic,transcriptomic,and metabolomic datasets provided a solid foundation for enhancing bamboo shoot quality and developing efficient gene-editing techniques.This study should facilitate research on D.brandisii and enhance its use as a food source and wood material by providing crucial genomic resources.
基金supported by the National Key Research and Development Program of China(No.2022YFF0606600)the Fundamental Research Funds for the Central Universities(No.N2229001).
文摘During the construction of an offshore wind farm(OWF),the capital cost of the collector cable system accounts for a large proportion of the total cost.Consequently,the optimal design of the collector system topology(CST)is one of the most crucial tasks in OWF planning.However,for a large-scale OWF,the optimal design of CST is a complex integer programming problem with high-dimension variables and various constraints.Therefore,it is difficult to acquire a high-quality optimal design scheme.To address this issue,this paper proposes a new grouping-based optimal design of CST for a large-scale OWF.First,all the wind turbines are divided into multiple groups according to their geographical locations and the maximum allowed connected wind turbines by each cable.This not only reduces the optimization dimension and difficulty,but also effectively satisfies the‘no cross’constraint by putting the geographically closed wind turbines into the same group.Secondly,the electrical topology among different wind turbines in each group is initially generated by an improved dynamic minimum spanning tree(DMST).The division groups of the OWF are then adjusted to further reduce the capital cost by improved simulated annealing.To verify the proposed technique,comparison case studies are carried out with five algorithms on two different OWF.
基金supported by the National Natural Science Foundation of China(42230503)。
文摘The scarcity of proxies and calibration models for quantitatively reconstructing millennial timescale seasonal temperature tremendously constraints our understanding of the Holocene thermal variation and its driven mechanisms.Here,we established two global warm-season temperature models by applying deep learning neural network analysis to the branched tetraether membrane lipids originating from surface soil and lacustrine sediment bacteria.We utilized these optimal models in global well-dated lacustrine,peatland,and loess profiles covering the Holocene.All reconstructions of warm-season temperatures,consistent with climate model simulations,indicate cooling trends since the early Holocene,primarily induced by decreased solar radiation in the Northern Hemisphere due to the precession peak at the early.We further demonstrated that the membrane lipids can effectively enhance the future millennial seasonal temperature research,including winter temperatures,without being restricted by geographical location and sedimentary carrier.
文摘The pneumonia caused by novel coronavirus SARS-CoV-2 infection in early December 2019,which was later named coronavirus disease 2019(COVID-19)by the World Health Organization(WHO),rapidly spread across the world.China has made extraordinary efforts to this unprecedented pandemic,put its response and control at a very high level of infectious disease management(Category B but with measures for Category A),given top priority to the people and their lives,and balanced the pandemic control and socio-economic development.After more than three years’fighting against this disease,China downgraded the management of COVID-19 to Category B infectious disease on January 8,2023 and the WHO declared the end of public health emergency on May 5,2023.However,the ending of pandemic does not mean that the disease is no longer a health threat.Experiences against COVID-19 from China and the whole world should be learned to prepare well for the future public health emergencies.This article gives a systematic review of the trajectory of COVID-19 development in China,summarizes the critical policy arrangements and provides evidence for the adjustment during policy making process,so as to share experiences with international community and contribute to the global health for all humanity.
