As one of China's most important ecological conservation regions,the source region of the Yellow River(SRYR)has a fragile ecological environment.Investigating land use transformations and their ecological conseque...As one of China's most important ecological conservation regions,the source region of the Yellow River(SRYR)has a fragile ecological environment.Investigating land use transformations and their ecological consequences in this region is of great significance for optimizing territorial spatial structure and promoting regional sustainable development.Based on the dominant functions of production-living-ecological space(PLES),we employed the land use transfer matrix and the standard deviational ellipse method to elucidate the spatiotemporal evolution characteristics of PLES in the SRYR from 2000 to 2020.Furthermore,the mechanism underlying the differentiation of eco-environmental effects in this region was explored using the optimal parameter-based geographical detector(OPGD)model.Results indicated that ecological space predominated within the PLES of the SRYR,accounting for approximately 98.74%of the total area.Living space was sparsely distributed in township areas with a proportion below 1.00%.Production space was mainly distributed in Guinan County and Gonghe County,accounting for about 1.16%of the area.In terms of the temporal scale,during 2000–2020,the overall eco-environmental quality of the SRYR exhibited an improving trend,primarily driven by the conversion of other ecological spaces into grassland ecological space.Interaction detection results revealed that the interaction between normalized difference vegetation index and gross domestic product was the strongest.In addition,the interaction between precipitation and temperature showed a significant bilinear enhancement effect.This finding suggests that the variations in eco-environmental quality in the SRYR during 2000–2020 have been jointly influenced by natural,climatic,and human factors.This study helps to provide a scientific basis for the rational layout of PLES and guiding ecological restoration efforts in the SRYR.展开更多
The Gansu-Qinghai contiguous region of the upper Yellow River is located in the transition zone between the Loess Plateau and the Qinghai-Tibet Plateau,characterized by fragile ecosystems and high sensitivity to clima...The Gansu-Qinghai contiguous region of the upper Yellow River is located in the transition zone between the Loess Plateau and the Qinghai-Tibet Plateau,characterized by fragile ecosystems and high sensitivity to climate change.As a critical ecological security barrier and water conservation area,it faces persistent tensions between development demands and ecological protection.Quantitative assessments of how production-living-ecological space(PLES)evolution affects ecological and environmental quality(EEQ)under long-term,multi-scenario conditions remain limited in such vulnerable regions.Understanding PLES-EEQ relationships is essential for optimizing territorial spatial planning and maintaining ecological security in the Yellow River basin.This study utilized land use data from 2000 to 2020 and the FLUS model to simulate PLES evolution from 2030 to 2060 under SSP1,SSP2,and SSP5 scenarios.The analytical framework integrated artificial neural networks and cellular automata with Shared Socioeconomic Pathways to project spatial configurations and assess EEQ in 2035.Living space expanded across all three scenarios while ecological space decreased.Production space increased by 125 km^(2) under SSP5 but declined in other scenarios.The EEQ index in 2035 showed improvements relative to the baseline value(0.4130)in 2020.Medium-to-high quality areas were primarily grassland and forest,whereas low-quality areas consisted mainly of unused land concentrated in the central and western regions.This study reveals a nonlinear relationship between ecological space quantity and quality,showing that structural optimization can enhance EEQ despite area reduction.The findings suggest that strengthening ecological protection redlines and restraining urban expansion are essential for territorial spatial optimization in ecologically fragile regions.展开更多
Satellite mega-constellations(SMCs)encounter significant operational challenges due to various space environmental effects.While the mechanisms underlying some of these effects have been studied from a physical perspe...Satellite mega-constellations(SMCs)encounter significant operational challenges due to various space environmental effects.While the mechanisms underlying some of these effects have been studied from a physical perspective,their precise impact on the network performance of SMCs remains unclear.To elucidate this further,this study investigates the spatiotemporal distribution characteristics of space environmental effects,such as solar radiation,ionizing radiation,and space debris,and the associated failure mechanisms in the nodes and links of SMCs.In addition,the impacts of solar radiation and single-event effects on performance of SMC system,particularly network throughput capacity,are examined.Results reveal that under the effect of the space environment,the throughput capacity degradation of SMC system varies with different parameters such as orbital altitude and inclination.Most importantly,the results bridge the gap between the physical phenomena of space environmental effects and network-level modeling.Finally,future research directions are prospected,regarding network topology control,constellation architecture,network routing techniques,and so on,to help mitigate network performance degradation due to space environmental effects.展开更多
文章基于CNKI、Web of Science两大数据库2005—2024年收录的图书馆学习空间研究文献,运用CiteSpace、Bicomb、SPSS软件进行可视化分析。结果显示,国外研究以技术驱动创新为主导,聚焦智能化技术与跨学科应用;而国内研究呈现理论创新与...文章基于CNKI、Web of Science两大数据库2005—2024年收录的图书馆学习空间研究文献,运用CiteSpace、Bicomb、SPSS软件进行可视化分析。结果显示,国外研究以技术驱动创新为主导,聚焦智能化技术与跨学科应用;而国内研究呈现理论创新与实践探索并重,通过大数据、AI等技术形成本土化解决方案。文章提出通过数字技术与人文关怀的平衡发展、国际化视野与本土化创新的有机结合、理论研究与实践应用的深度融合,为我国图书馆学习空间的研究提供借鉴与参考。展开更多
The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for ...The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for aircraft mission effectiveness evaluation and design space exploration based on Virtual Operational Test(VOT),incorporating Virtual Open Scenario(VOS)and User in Scenarios(UIS)concepts.By employing modeling and simulation technologies in the early stages of aircraft development and design,a virtual environment can be constructed,allowing aircraft users to participate more closely and conveniently in the design process.Virtual tests conducted by users within the mission context provide data on mission effectiveness and critical user feedback.This paper outlines the main components of the virtual operational test process and related conceptual methods,and discusses an open support system framework that supports VOT.The effectiveness and adaptability of the method are demonstrated through two case studies:a beyond-visual-range air combat scenario and a helicopter ground attack scenario.These case studies demonstrate the evaluation of aircraft mission effectiveness and the sensitivity analysis and optimization of design and operational parameters based on VOT.展开更多
The aim of this study is to develop an understanding on the contributing influences that occur among qualities of public space,public space aesthetics,the comfort derived in public space and public space accessibility...The aim of this study is to develop an understanding on the contributing influences that occur among qualities of public space,public space aesthetics,the comfort derived in public space and public space accessibility in science cities.This study seeks to investigate the extent at which public space attributes impact on one another.The emphasis accruing to open greenery including public spaces in the physical development of science cities necessitates the selection of Cyberjaya Malaysia as the study area.Survey questionnaires were used to investigate potential respondent’s perceptions on public space utilization and the feedback was validated with SEM(structural equation modelling).The findings indicated that the accessibility attributes significantly influenced other public space utilization attributes while good quality of public space influenced the comfort derived from it.Attractiveness of public space was found not capable to predict the comfort and good quality of public space.展开更多
The goal of this paper is to establish the boundedness of the p-adic fractional integral operator with rough kernel I_(β,Ω′)^(p)and its commutators generated by b∈Λ_(γ)(Q_(p)^(n))(0<γ<1)and the I_(β,Ω′...The goal of this paper is to establish the boundedness of the p-adic fractional integral operator with rough kernel I_(β,Ω′)^(p)and its commutators generated by b∈Λ_(γ)(Q_(p)^(n))(0<γ<1)and the I_(β,Ω′)^(p) on grand p-adic Herz spaces.展开更多
This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mi...This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mission is disturbed by the measurement noise and the target adversarial behavior.To address these problems,a model-free Combined Adaptive-length Datadriven Predictive Controller(CADPC)is proposed.It consists of a separated subsystem identification method and a combined predictive control strategy.The subsystem identification method is composed of an adaptive data length,thereby reducing sensitivity to undetermined measurement noises and disturbances.Based on the subsystem identification,the combined predictive controller is established,reducing calculating resource.The stability of the CADPC is rigorously proven using the Input-to-State Stable(ISS)theorem and the small-gain theorem.Simulations demonstrate that CADPC effectively handles the model-free space robot post operation in the presence of significant disturbances,state measurement noise,and control input errors.It achieves improved steady-state accuracy,reduced steady-state control consumption,and minimized control input chattering.展开更多
Objective To assess the independent and combined effects of air pollutants,meteorological factors,and greenspace exposure on new tuberculosis(TB)cases.Methods TB case data from Shanghai(2013–2018)were obtained from t...Objective To assess the independent and combined effects of air pollutants,meteorological factors,and greenspace exposure on new tuberculosis(TB)cases.Methods TB case data from Shanghai(2013–2018)were obtained from the Shanghai Center for Disease Control and Prevention.Environmental data on air pollutants,meteorological variables,and greenspace exposure were obtained from the National Tibetan Plateau Data Center.We employed a distributed-lag nonlinear model to assess the effects of these environmental factors on TB cases.Results Increased TB risk was linked to PM_(2.5),PM_(10),and rainfall,whereas NO_(2),SO_(2),and air pressure were associated with a reduced risk.Specifically,the strongest cumulative effects occurred at various lags:PM_(2.5)(RR=1.166,95%CI:1.026–1.325)at 0–19 weeks;PM_(10)(RR=1.167,95%CI:1.028–1.324)at 0–18 weeks;NO_(2)(RR=0.968,95%CI:0.938–0.999)at 0–1 weeks;SO_(2)(RR=0.945,95%CI:0.894–0.999)at 0–2 weeks;air pressure(RR=0.604,95%CI:0.447–0.816)at 0–8 weeks;and rainfall(RR=1.404,95%CI:1.076–1.833)at 0–22 weeks.Green space exposure did not significantly impact TB cases.Additionally,low temperatures amplified the effect of PM_(2.5)on TB.Conclusion Exposure to PM_(2.5),PM_(10),and rainfall increased the risk of TB,highlighting the need to address air pollutants for the prevention of TB in Shanghai.展开更多
Local Climate Zones(LCZs)provide a standardized framework for analyzing urban thermal environment.Examining the interactive effects of building and green space patterns on land surface temperature(LST)within LCZs is e...Local Climate Zones(LCZs)provide a standardized framework for analyzing urban thermal environment.Examining the interactive effects of building and green space patterns on land surface temperature(LST)within LCZs is essential for uncovering urban cooling mechanisms and developing strategies for heat-mitigation urban design.Therefore,this study employed one-way ANOVA and Duncan's multiple comparison to test compare the significant differences of LST among LCZs 1-6,and applied the XGBoost model to quantify the interactive effects of building and green space indicators on LST,and to identify the threshold ranges of their cooling effects.The results showed that LCZ 2 exhibited the highest LST,while LCZ 4 recorded the lowest.Average building volume(BAV),building coverage ratio(BCR),green cover area(GCA),and the total edge length of green space(GTE)were identified as the key indicators driving the interactive effects on LST.In LCZ 2,when BAV exceeded 1800 m^(3),the interaction of higher GCA and GTE contributed to lower LST.When BCR was less than 0.6 in LCZs 4-5,lower GCA and GTE values enhanced the LST reduction.The results provided a strategic basis for urban thermal environment mitigation and sustainable development under the LCZ framework.展开更多
This study investigates a metal laser direct-writing additive manufacturing process for potential in-space applications.The feasibility of stable deposition under various gravitational conditions—specifically at angl...This study investigates a metal laser direct-writing additive manufacturing process for potential in-space applications.The feasibility of stable deposition under various gravitational conditions—specifically at angles of 0°,90°,and 180°between the deposition direction and gravitational acceleration,and under zero-gravity—is demonstrated.The analysis reveals that a stable metal deposition layer can be formed under different gravity conditions by establishing a strong liquid bridge connection with the substrate;however,the direction of gravitational acceleration significantly affects the cross-sectional morphology of the deposition layer.By comparing different parameters,it is found that the best cross-sectional morphology can be obtained when the wire feeding speed is 120 mm/min and the ratio to the moving speed is 1.0.Notably,a higher wire feeding rate correlates with an increased temperature gradient within the heat-affected zone.On this basis,a thin-walled cylindrical piece printed at a 90°angle between the deposition gravity directions exhibits an outer surface cylindricity of 0.294mm,a size deviation range of-0.168 mm to 0.126 mm,a maximum size deviation of 0.168 mm on the outer surface,and a surface roughness of less than 8.142μm.The results indicate that this process produces printed parts with high surface quality and geometric accuracy.Tensile tests on the printed parts demonstrate that they possess excellent mechanical properties.This study provides valuable insights and a meaningful exploration of future in-orbit metal manufacturing.展开更多
This article reviews the construction process of National Wetland Parks,the ecological effects of blue-green spaces,and their significance in wetland park development.It explores the functions of wetland parks in biod...This article reviews the construction process of National Wetland Parks,the ecological effects of blue-green spaces,and their significance in wetland park development.It explores the functions of wetland parks in biodiversity conservation,water purification,climate regulation,and other ecological functions.Finally,it proposes of enhancing the protection and management of wetland parks,in the hope of promoting the full realization of their ecological benefits and ensure sustainable development.展开更多
Low-frequency signals have been proven valuable in the fields of target detection and geological exploration.Nevertheless,the practical implementation of these signals is hindered by large antenna diameters,limiting t...Low-frequency signals have been proven valuable in the fields of target detection and geological exploration.Nevertheless,the practical implementation of these signals is hindered by large antenna diameters,limiting their potential applications.Therefore,it is imperative to study the creation of lowfrequency signals using antennas with suitable dimensions.In contrast to conventional mechanical antenna techniques,our study generates low-frequency signals in the spatial domain utilizing the principle of the Doppler effect.We also defines the antenna array architecture,the timing sequency,and the radiating element signal waveform,and provides experimental prototypes including 8/64 antennas based on earlier research.In the conducted experiments,121 MHz,40 MHz,and 10 kHz composite signals are generated by 156 MHz radiating element signals.The composite signal spectrum matches the simulations,proving our low-frequency signal generating method works.This holds significant implications for research on generating low-frequency signals with small-sized antennas.展开更多
The detonation of fuel-rich explosives yields combustible products that persistently burn upon mixing with ambient oxygen,releasing additional energy through a phenomenon known as the afterburning effect.This process ...The detonation of fuel-rich explosives yields combustible products that persistently burn upon mixing with ambient oxygen,releasing additional energy through a phenomenon known as the afterburning effect.This process greatly influences the evolution of confined blast loading and the subsequent structural response,which is crucial in confined blast scenarios.Given the complex nature of the reaction process,accurate analysis of the afterburning effect remains challenging.Previous studies have either overlooked the mechanisms of detonation product combustion or failed to provide experimental validation.This study introduces a three-dimensional model to effectively characterize the combustion of detonation products.The model integrates chemical reaction source terms into the governing equations to consider the combustion processes.Numerical simulations and experimental tests were conducted to analyze the combustion and energy release from the detonation products of fuel-rich explosives in confined spaces.Approximately 50%of the energy was released during the combustion of detonation products in a confined TNT explosion.Although the combustion of these products was much slower than the detonation process,it aligned with the dynamic response of the structure,which enhanced the explosive yield.Excluding afterburning from the analysis reduced the center-point deformation of the structure by 30%.Following the inclusion of afterburning,the simulated quasistatic pressure increased by approximately 45%.Subsequent comparisons highlighted the merits of the proposed approach over conventional methods.This approach eliminates the reliance on empirical parameters,such as the amount and rate of energy release during afterburning,thereby laying the foundation for understanding load evolution in more complex environments,such as ships,buildings,and underground tunnels.展开更多
In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and...In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants.展开更多
In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale in...In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale inequalities of mixed quasi-martingale Hardy spaces.Moreover,we furnish sufficient conditions for the boundedness ofσ-sublinear operators in these spaces.These findings extend the existing conclusions regarding mixed quasi-martingale Hardy spaces defined with the help of the mixed L_(p)-norm.展开更多
Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms lig...Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms ligand bonds or hydrogen bonds with sulfur ions in lithium polysulfides(LiPSs),thus inhibiting the shuttle effect.Electrochemical analyses demonstrated that lithium‑sulfur(Li‑S)batteries employing the NH2‑SS interlayer exhibited discharge specific capacities of 1048 and 789 mAh·g^(-1) at 0.2C and 2C,respectively,and even at 4C,the initial discharge specific capacity remained at 590 mAh·g^(-1),outperforming the Li‑S battery with unmodified SS as the interlayer.展开更多
基金financially supported by the Qinghai Provincial Applied Basic Research Program,China(2024-ZJ-953)。
文摘As one of China's most important ecological conservation regions,the source region of the Yellow River(SRYR)has a fragile ecological environment.Investigating land use transformations and their ecological consequences in this region is of great significance for optimizing territorial spatial structure and promoting regional sustainable development.Based on the dominant functions of production-living-ecological space(PLES),we employed the land use transfer matrix and the standard deviational ellipse method to elucidate the spatiotemporal evolution characteristics of PLES in the SRYR from 2000 to 2020.Furthermore,the mechanism underlying the differentiation of eco-environmental effects in this region was explored using the optimal parameter-based geographical detector(OPGD)model.Results indicated that ecological space predominated within the PLES of the SRYR,accounting for approximately 98.74%of the total area.Living space was sparsely distributed in township areas with a proportion below 1.00%.Production space was mainly distributed in Guinan County and Gonghe County,accounting for about 1.16%of the area.In terms of the temporal scale,during 2000–2020,the overall eco-environmental quality of the SRYR exhibited an improving trend,primarily driven by the conversion of other ecological spaces into grassland ecological space.Interaction detection results revealed that the interaction between normalized difference vegetation index and gross domestic product was the strongest.In addition,the interaction between precipitation and temperature showed a significant bilinear enhancement effect.This finding suggests that the variations in eco-environmental quality in the SRYR during 2000–2020 have been jointly influenced by natural,climatic,and human factors.This study helps to provide a scientific basis for the rational layout of PLES and guiding ecological restoration efforts in the SRYR.
基金funded by the National Natural Science Foundation of China(Grant No.42461038 and No.42161043).
文摘The Gansu-Qinghai contiguous region of the upper Yellow River is located in the transition zone between the Loess Plateau and the Qinghai-Tibet Plateau,characterized by fragile ecosystems and high sensitivity to climate change.As a critical ecological security barrier and water conservation area,it faces persistent tensions between development demands and ecological protection.Quantitative assessments of how production-living-ecological space(PLES)evolution affects ecological and environmental quality(EEQ)under long-term,multi-scenario conditions remain limited in such vulnerable regions.Understanding PLES-EEQ relationships is essential for optimizing territorial spatial planning and maintaining ecological security in the Yellow River basin.This study utilized land use data from 2000 to 2020 and the FLUS model to simulate PLES evolution from 2030 to 2060 under SSP1,SSP2,and SSP5 scenarios.The analytical framework integrated artificial neural networks and cellular automata with Shared Socioeconomic Pathways to project spatial configurations and assess EEQ in 2035.Living space expanded across all three scenarios while ecological space decreased.Production space increased by 125 km^(2) under SSP5 but declined in other scenarios.The EEQ index in 2035 showed improvements relative to the baseline value(0.4130)in 2020.Medium-to-high quality areas were primarily grassland and forest,whereas low-quality areas consisted mainly of unused land concentrated in the central and western regions.This study reveals a nonlinear relationship between ecological space quantity and quality,showing that structural optimization can enhance EEQ despite area reduction.The findings suggest that strengthening ecological protection redlines and restraining urban expansion are essential for territorial spatial optimization in ecologically fragile regions.
基金supported in part by the National Natural Science Foundation of China(62495022,62495020,62422114,62461160329,62121001,and 62371360)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(CAST2022QNRC001).
文摘Satellite mega-constellations(SMCs)encounter significant operational challenges due to various space environmental effects.While the mechanisms underlying some of these effects have been studied from a physical perspective,their precise impact on the network performance of SMCs remains unclear.To elucidate this further,this study investigates the spatiotemporal distribution characteristics of space environmental effects,such as solar radiation,ionizing radiation,and space debris,and the associated failure mechanisms in the nodes and links of SMCs.In addition,the impacts of solar radiation and single-event effects on performance of SMC system,particularly network throughput capacity,are examined.Results reveal that under the effect of the space environment,the throughput capacity degradation of SMC system varies with different parameters such as orbital altitude and inclination.Most importantly,the results bridge the gap between the physical phenomena of space environmental effects and network-level modeling.Finally,future research directions are prospected,regarding network topology control,constellation architecture,network routing techniques,and so on,to help mitigate network performance degradation due to space environmental effects.
文摘文章基于CNKI、Web of Science两大数据库2005—2024年收录的图书馆学习空间研究文献,运用CiteSpace、Bicomb、SPSS软件进行可视化分析。结果显示,国外研究以技术驱动创新为主导,聚焦智能化技术与跨学科应用;而国内研究呈现理论创新与实践探索并重,通过大数据、AI等技术形成本土化解决方案。文章提出通过数字技术与人文关怀的平衡发展、国际化视野与本土化创新的有机结合、理论研究与实践应用的深度融合,为我国图书馆学习空间的研究提供借鉴与参考。
文摘The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for aircraft mission effectiveness evaluation and design space exploration based on Virtual Operational Test(VOT),incorporating Virtual Open Scenario(VOS)and User in Scenarios(UIS)concepts.By employing modeling and simulation technologies in the early stages of aircraft development and design,a virtual environment can be constructed,allowing aircraft users to participate more closely and conveniently in the design process.Virtual tests conducted by users within the mission context provide data on mission effectiveness and critical user feedback.This paper outlines the main components of the virtual operational test process and related conceptual methods,and discusses an open support system framework that supports VOT.The effectiveness and adaptability of the method are demonstrated through two case studies:a beyond-visual-range air combat scenario and a helicopter ground attack scenario.These case studies demonstrate the evaluation of aircraft mission effectiveness and the sensitivity analysis and optimization of design and operational parameters based on VOT.
文摘The aim of this study is to develop an understanding on the contributing influences that occur among qualities of public space,public space aesthetics,the comfort derived in public space and public space accessibility in science cities.This study seeks to investigate the extent at which public space attributes impact on one another.The emphasis accruing to open greenery including public spaces in the physical development of science cities necessitates the selection of Cyberjaya Malaysia as the study area.Survey questionnaires were used to investigate potential respondent’s perceptions on public space utilization and the feedback was validated with SEM(structural equation modelling).The findings indicated that the accessibility attributes significantly influenced other public space utilization attributes while good quality of public space influenced the comfort derived from it.Attractiveness of public space was found not capable to predict the comfort and good quality of public space.
基金Supported by Natural Science Foundation of China(12461021)。
文摘The goal of this paper is to establish the boundedness of the p-adic fractional integral operator with rough kernel I_(β,Ω′)^(p)and its commutators generated by b∈Λ_(γ)(Q_(p)^(n))(0<γ<1)and the I_(β,Ω′)^(p) on grand p-adic Herz spaces.
基金supported by the National Natural Science Foundation of China(No.12372045)the National Key Research and the Development Program of China(Nos.2023YFC2205900,2023YFC2205901)。
文摘This paper solves the problem of model-free dual-arm space robot maneuvering after non-cooperative target capture under high control quality requirements.The explicit system model is unavailable,and the maneuvering mission is disturbed by the measurement noise and the target adversarial behavior.To address these problems,a model-free Combined Adaptive-length Datadriven Predictive Controller(CADPC)is proposed.It consists of a separated subsystem identification method and a combined predictive control strategy.The subsystem identification method is composed of an adaptive data length,thereby reducing sensitivity to undetermined measurement noises and disturbances.Based on the subsystem identification,the combined predictive controller is established,reducing calculating resource.The stability of the CADPC is rigorously proven using the Input-to-State Stable(ISS)theorem and the small-gain theorem.Simulations demonstrate that CADPC effectively handles the model-free space robot post operation in the presence of significant disturbances,state measurement noise,and control input errors.It achieves improved steady-state accuracy,reduced steady-state control consumption,and minimized control input chattering.
基金supported by the National Key Research and Development Program of China[2023YFC2307305]Shenzhen Medical Research Fund[B2303003]+3 种基金the Zhujiang Innovation and Entrepreneurship Talents Program[2021ZT09Y544]the Shenzhen Science and Technology Program[ZDSYS20230626091203007]Shanghai CDC(Shanghai three-year(2023–2025)action plan to strengthen the public health system[GWVI–11.1–05])Top Young Talents in Shanghai。
文摘Objective To assess the independent and combined effects of air pollutants,meteorological factors,and greenspace exposure on new tuberculosis(TB)cases.Methods TB case data from Shanghai(2013–2018)were obtained from the Shanghai Center for Disease Control and Prevention.Environmental data on air pollutants,meteorological variables,and greenspace exposure were obtained from the National Tibetan Plateau Data Center.We employed a distributed-lag nonlinear model to assess the effects of these environmental factors on TB cases.Results Increased TB risk was linked to PM_(2.5),PM_(10),and rainfall,whereas NO_(2),SO_(2),and air pressure were associated with a reduced risk.Specifically,the strongest cumulative effects occurred at various lags:PM_(2.5)(RR=1.166,95%CI:1.026–1.325)at 0–19 weeks;PM_(10)(RR=1.167,95%CI:1.028–1.324)at 0–18 weeks;NO_(2)(RR=0.968,95%CI:0.938–0.999)at 0–1 weeks;SO_(2)(RR=0.945,95%CI:0.894–0.999)at 0–2 weeks;air pressure(RR=0.604,95%CI:0.447–0.816)at 0–8 weeks;and rainfall(RR=1.404,95%CI:1.076–1.833)at 0–22 weeks.Green space exposure did not significantly impact TB cases.Additionally,low temperatures amplified the effect of PM_(2.5)on TB.Conclusion Exposure to PM_(2.5),PM_(10),and rainfall increased the risk of TB,highlighting the need to address air pollutants for the prevention of TB in Shanghai.
基金financial support from the National Natural Science Foundation of China(32271661,32130068).
文摘Local Climate Zones(LCZs)provide a standardized framework for analyzing urban thermal environment.Examining the interactive effects of building and green space patterns on land surface temperature(LST)within LCZs is essential for uncovering urban cooling mechanisms and developing strategies for heat-mitigation urban design.Therefore,this study employed one-way ANOVA and Duncan's multiple comparison to test compare the significant differences of LST among LCZs 1-6,and applied the XGBoost model to quantify the interactive effects of building and green space indicators on LST,and to identify the threshold ranges of their cooling effects.The results showed that LCZ 2 exhibited the highest LST,while LCZ 4 recorded the lowest.Average building volume(BAV),building coverage ratio(BCR),green cover area(GCA),and the total edge length of green space(GTE)were identified as the key indicators driving the interactive effects on LST.In LCZ 2,when BAV exceeded 1800 m^(3),the interaction of higher GCA and GTE contributed to lower LST.When BCR was less than 0.6 in LCZs 4-5,lower GCA and GTE values enhanced the LST reduction.The results provided a strategic basis for urban thermal environment mitigation and sustainable development under the LCZ framework.
文摘This study investigates a metal laser direct-writing additive manufacturing process for potential in-space applications.The feasibility of stable deposition under various gravitational conditions—specifically at angles of 0°,90°,and 180°between the deposition direction and gravitational acceleration,and under zero-gravity—is demonstrated.The analysis reveals that a stable metal deposition layer can be formed under different gravity conditions by establishing a strong liquid bridge connection with the substrate;however,the direction of gravitational acceleration significantly affects the cross-sectional morphology of the deposition layer.By comparing different parameters,it is found that the best cross-sectional morphology can be obtained when the wire feeding speed is 120 mm/min and the ratio to the moving speed is 1.0.Notably,a higher wire feeding rate correlates with an increased temperature gradient within the heat-affected zone.On this basis,a thin-walled cylindrical piece printed at a 90°angle between the deposition gravity directions exhibits an outer surface cylindricity of 0.294mm,a size deviation range of-0.168 mm to 0.126 mm,a maximum size deviation of 0.168 mm on the outer surface,and a surface roughness of less than 8.142μm.The results indicate that this process produces printed parts with high surface quality and geometric accuracy.Tensile tests on the printed parts demonstrate that they possess excellent mechanical properties.This study provides valuable insights and a meaningful exploration of future in-orbit metal manufacturing.
基金Supported by Henan Province Key Technology Research Program(23210-2320262)Key Scientific Research Projects Program of Henan Higher Education Institutions(22B180011)+1 种基金Pingdingshan University 2023 Curriculum Ideological and Political Education Demonstration Course-Ecological EngineeringPingdingshan University Education and Teaching Reform Research Project(2021-JY55).
文摘This article reviews the construction process of National Wetland Parks,the ecological effects of blue-green spaces,and their significance in wetland park development.It explores the functions of wetland parks in biodiversity conservation,water purification,climate regulation,and other ecological functions.Finally,it proposes of enhancing the protection and management of wetland parks,in the hope of promoting the full realization of their ecological benefits and ensure sustainable development.
基金Science and Technology Project of Aerospace Information Research Institute,Chinese Academy of Sciences(Y910340Z2F)Science and Technology Project of BBEF(E3E2010201)。
文摘Low-frequency signals have been proven valuable in the fields of target detection and geological exploration.Nevertheless,the practical implementation of these signals is hindered by large antenna diameters,limiting their potential applications.Therefore,it is imperative to study the creation of lowfrequency signals using antennas with suitable dimensions.In contrast to conventional mechanical antenna techniques,our study generates low-frequency signals in the spatial domain utilizing the principle of the Doppler effect.We also defines the antenna array architecture,the timing sequency,and the radiating element signal waveform,and provides experimental prototypes including 8/64 antennas based on earlier research.In the conducted experiments,121 MHz,40 MHz,and 10 kHz composite signals are generated by 156 MHz radiating element signals.The composite signal spectrum matches the simulations,proving our low-frequency signal generating method works.This holds significant implications for research on generating low-frequency signals with small-sized antennas.
基金supported by the National Natural Science Foundation of China(Grant Nos.52171318 and 12202329)Joint Foundation of the Ministry of Education(Grant No.8091B022105)。
文摘The detonation of fuel-rich explosives yields combustible products that persistently burn upon mixing with ambient oxygen,releasing additional energy through a phenomenon known as the afterburning effect.This process greatly influences the evolution of confined blast loading and the subsequent structural response,which is crucial in confined blast scenarios.Given the complex nature of the reaction process,accurate analysis of the afterburning effect remains challenging.Previous studies have either overlooked the mechanisms of detonation product combustion or failed to provide experimental validation.This study introduces a three-dimensional model to effectively characterize the combustion of detonation products.The model integrates chemical reaction source terms into the governing equations to consider the combustion processes.Numerical simulations and experimental tests were conducted to analyze the combustion and energy release from the detonation products of fuel-rich explosives in confined spaces.Approximately 50%of the energy was released during the combustion of detonation products in a confined TNT explosion.Although the combustion of these products was much slower than the detonation process,it aligned with the dynamic response of the structure,which enhanced the explosive yield.Excluding afterburning from the analysis reduced the center-point deformation of the structure by 30%.Following the inclusion of afterburning,the simulated quasistatic pressure increased by approximately 45%.Subsequent comparisons highlighted the merits of the proposed approach over conventional methods.This approach eliminates the reliance on empirical parameters,such as the amount and rate of energy release during afterburning,thereby laying the foundation for understanding load evolution in more complex environments,such as ships,buildings,and underground tunnels.
文摘In this paper,we present a necessary and sufficient condition for hyponormal block Toeplitz operators T on the vector-valued weighted Bergman space with symbolsΦ(z)=G^(*)(z)+F(z),where F(z)=∑^(N)_(i)=1 A_(i)z^(i)and G(z)=∑^(N)_(i)=1 A_(−i)z^(i),A_(i)ae culants.
基金Supported by the National Natural Science Foundation of China(11871195)。
文摘In this article,we conduct a study on mixed quasi-martingale Hardy spaces that are defined by means of the mixed L_(p)-norm.By utilizing Doob’s inequalities,we explore the atomic decomposition and quasi-martingale inequalities of mixed quasi-martingale Hardy spaces.Moreover,we furnish sufficient conditions for the boundedness ofσ-sublinear operators in these spaces.These findings extend the existing conclusions regarding mixed quasi-martingale Hardy spaces defined with the help of the mixed L_(p)-norm.
文摘Herein,3‑aminopropyltriethoxysilane(APTES)was used to modify F‑containing silica slag(SS)by simple grafting and served as a multifunctional barrier layer.The amino group(—NH2)in the amino‑modified SS(NH2‑SS)forms ligand bonds or hydrogen bonds with sulfur ions in lithium polysulfides(LiPSs),thus inhibiting the shuttle effect.Electrochemical analyses demonstrated that lithium‑sulfur(Li‑S)batteries employing the NH2‑SS interlayer exhibited discharge specific capacities of 1048 and 789 mAh·g^(-1) at 0.2C and 2C,respectively,and even at 4C,the initial discharge specific capacity remained at 590 mAh·g^(-1),outperforming the Li‑S battery with unmodified SS as the interlayer.
