The efficient development of the urban economy is a major concern of scholars in the fields of geography and urban science.In the context of globalization,informatization,industrialization,and urbanization,the externa...The efficient development of the urban economy is a major concern of scholars in the fields of geography and urban science.In the context of globalization,informatization,industrialization,and urbanization,the external relationships of China's cities are experiencing the joint action of urban scale hierarchies and connection networks(“hierarchy-network”).However,under the interactive effect of the two,the mechanism of urban economic efficiency(UEE)is unclear.Therefore,based on Baidu migration data,the regionalization with dynamically constrained agglomerative clustering and partitioning(REDCAP)method,and a spatial simultaneous equation model,this paper analyzes the UEE spatial pattern and mechanism in China.The results indicate that:(1)the urban economy has a superlinear relationship with the population size.However,the benefit of this superlinear growth is in marginal decline.(2)The UEE shows a pattern of differentiation between China's eastern,then central,and then western region.Also,local differences are found within the three major sub-regions.(3)The increase of urban network centrality can promote UEE,while the impact of urban scale is negative.(4)There is regional heterogeneity of the interactive effect of“hierarchy-network”on UEE.This study reveals the influencing mechanism of UEE and also provides policy implications for the development of UEE.展开更多
It is urgent and important to explore the dynamic evolution in comprehensive transportation green efficiency(CTGE)in the context of green development.We constructed a social development index that reflects the social ...It is urgent and important to explore the dynamic evolution in comprehensive transportation green efficiency(CTGE)in the context of green development.We constructed a social development index that reflects the social benefits of transportation services,and incorporated it into the comprehensive transportation efficiency evaluation framework as an expected output.Based on the panel data of 30 regions in China from 2003-2018,the CTGE in China was measured using the slacks-based measure-data envelopment analysis(SBM-DEA)model.Further,the dynamic evolution trends of CTGE were determined using the spatial Markov model and exploratory spatio-temporal data analysis(ESTDA)technique from a spatio-temporal perspective.The results showed that the CTGE shows a U-shaped change trend but with an overall low level and significant regional differences.The state transition of CTGE has a strong spatial dependence,and there exists the phenomenon of“club convergence”.Neighbourhood background has a significant impact on the CTGE transition types,and the spatial spillover effect is pronounced.The CTGE has an obvious positive correlation and spatial agglomeration characteristics.The geometric characteristics of the LISA time path show that the evolution process of local spatial structure and local spatial dependence of China’s CTGE is stable,but the integration of spatial evolution is weak.The spatio-temporal transition results of LISA indicate that the CTGE has obvious transfer inertness and has certain path-dependence and spatial locking characteristics,which will become the major difficulty in improving the CTGE.展开更多
The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandw...The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandwidth synthetically.As a part of beam-wave interaction section,buncher section is simulated by Particle-In-Cell(PIC) code to observe the bunching process of electron beam to achieve high conversion efficiency of electron beam and RF field.When it comes to the other part,output circuit is designed as a three-section filter by an output cavity loaded with Chebyshev filter,and the cold test results are given.The beam-wave interaction is simulated by EGUN code and Arsenal-MSU code respectively.The simulated results indicated that,the existence of power dips in the operating bandwidth is verified by Arsenal-MSU code,comparing proper results by EGUN code.Then,the method that design parameters are not adjusted except parameters of buncher cavities to remove potential power dips is described.What is more,the simulated results of electron optics system are given by EGUN code and Arsenal-MSU code respectively.The further hot test results of klystron prove that the whole design of beam-wave interaction is effective.展开更多
Most of acridine based thermally activated delayed fluorescence(TADF)emitters are characterized by advantageous reverse intersystem crossing(RISC)rate(kRISCs)due to the perpendicular orientation of the acridine donor ...Most of acridine based thermally activated delayed fluorescence(TADF)emitters are characterized by advantageous reverse intersystem crossing(RISC)rate(kRISCs)due to the perpendicular orientation of the acridine donor to the acceptor moiety,but suffer from a poor radiation rate(kr)typically in the order of 10^(6) s^(−1).Herein,two sky blue TADF emitters 3,6-DMAC-AD-Py and 3,6-SFAC-AD-Py were developed by linking acridine(DMAC)and spiro-fluorene-acridine(SFAC)donors to 10-(pyridin-2-yl)acridin-9(10H)-one(AD-Py)acceptor.Larger SFAC and electron-deficient pyridyl groups are deliberately incorporated in 3,6-SFACAD-Py since the unique through-space interaction between them is designed to drive the rotation of inner acridine ring in SFAC for enhancing frontier molecular orbitals overlap while keeping a decent TADF behavior.Thus,the kr of 3,6-SFACAD-Py is increased to 1.5×10^(7) s^(−1).Simultaneously,SFAC donors improve spin orbital coupling strength and reduce the energy gaps,generating kRISC of 1.8×10^(6) s^(−1).This is the first acridine donor based TADF emitter realizing kr of 10^(7) s^(−1) and kRISC of 10^(6) s^(−1) by a through-space interaction strategy.3,6-SFACAD-Py enables a highly efficient sky-blue organic light-emitting diode with a maximum external quantum efficiency(EQE)of 34.7%and Commission International de I'Eclairage coordinates of(0.19,0.37).More importantly,the EQE still remained 27.6%and 16.9%at high brightness of 1000 and 10,000 cd m^(−2).展开更多
Soybean (Glycine max (L.) Merrill) is one of the most important oil and protein sources in the world. Interactive effect of elevated carbon dioxide (CO2) and soil water availability potentially impact future food secu...Soybean (Glycine max (L.) Merrill) is one of the most important oil and protein sources in the world. Interactive effect of elevated carbon dioxide (CO2) and soil water availability potentially impact future food security of the world under climate change. A rhizotron growth chamber experiment was conducted to study soil moisture interactions with elevated CO2 on gaseous exchange parameters of soybean under two CO2 concentrations (380 and 800 μmol·mol-1) with three soil moisture levels. Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%), intercellular CO2 concentration (16.68% and 12.28%), relative intercellular CO2 concentration (17.4% and 11.2%), and transpiration rate (43.6% and 39%) at 42 and 47 DAP. This down-regulation of photosynthesis was probably caused by low leaf nitrogen content and decrease in uptake of nutrients due to decrease in stomatal conductance and transpiration rate. Water use efficiency (WUE) increased under elevated CO2 because increase in total dry weight of plant was greater than that of water use under high CO2 conditions. Plants under normal and high soil moisture levels had significantly higher photosynthetic rate (7% to 16%) favored by optimum soil moisture content and high specific water content of soybean plants. Total dry matter production was significantly high when plants grown under elevated CO2 with normal (74.3% to 137.3%) soil moisture level. Photosynthetic rate was significantly and positively correlated with leaf conductance and intercellular CO2 concentration but WUE was significantly negatively correlated with leaf conductance, intercellular CO2 concentration and transpiration rate. However, the effect of high CO2 on plants depends on availability of nutrients and soil moisture for positive feedback from CO2 enrichment.展开更多
Adopting a soft site model built on soft interlayer soil foundation,a shaking table test for soft interlayer soil-isolated structure interaction is conducted to investigate the seismic response of isolated structure o...Adopting a soft site model built on soft interlayer soil foundation,a shaking table test for soft interlayer soil-isolated structure interaction is conducted to investigate the seismic response of isolated structure on soft site,and analyze its isolation effect.Test results show that the test can reflect the earthquake response characteristics of isolated structure on soft site.It is on soft site that the dynamic characteristics of isolated structure,acceleration magnification factor(AMF)of isolated structure and isolation efficiency of the isolation layer differ from those on rigid foundation with an soil-structure interaction(SSI)effect,represented by the reduction in fundamental vibration frequency of isolated structure and the increase of damping ratio with changes of the SSI effect.SSI can either increase or decrease AMF of isolated structure on soft site,depending on the characteristics of earthquake motion input.Furthermore,the isolation efficiency of isolation layer on soft site is decreased with the SSI effect,which is related to the peak ground acceleration(PGA)and the characteristics of earthquake motion input.展开更多
We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in...We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.展开更多
This study delves into the intricate relationship between iron(Fe)content in kaolinite and its impact on the adsorption behavior of sodium oleate.The effects of different iron concentrations on adsorption energy,hydro...This study delves into the intricate relationship between iron(Fe)content in kaolinite and its impact on the adsorption behavior of sodium oleate.The effects of different iron concentrations on adsorption energy,hydrogen bond kinetics and adsorption efficiency were studied through simulation and experimental verification.The results show that the presence of iron in the kaolinite structure significantly improves the adsorption capacity of sodium oleate.Kaolinite samples with high iron content have better adsorption properties,lower adsorption energy levels and shorter and stronger hydrogen bonds than pure kaolinite.The optimal concentration of oleic acid ions for achieving maximum adsorption efficiency was identified as 1.2 mmol/L across different kaolinite samples.At this concentration,the adsorption rates and capacities reach their peak,with Fe-enriched kaolinite samples exhibiting notably higher flotation recovery rates.This optimal concentration represents a balance between sufficient oleic acid ion availability for surface interactions and the prevention of self-aggregation phenomena that could hinder adsorption.This study offers promising avenues for optimizing the flotation process in mineral processing applications.展开更多
The direct finite element method is a type commonly used for nonlinear seismic soil-structure interaction(SSI)analysis.This method introduces a truncated boundary referred to as an artificial boundary meant to divide ...The direct finite element method is a type commonly used for nonlinear seismic soil-structure interaction(SSI)analysis.This method introduces a truncated boundary referred to as an artificial boundary meant to divide the soil-structure system into finite and infinite domains.An artificial boundary condition is used on a truncated boundary to achieve seismic input and simulate the wave radiation effect of infinite domain.When the soil layer is particularly thick,especially for a three-dimensional problem,the computational efficiency of seismic SSI analysis is very low due to the large size of the finite element model,which contains an whole thick soil layer.In this paper,an accurate and efficient scheme is developed to solve the nonlinear seismic SSI problem regarding thick soil layers.The process consists of nonlinear site response and SSI analysis.The nonlinear site response analysis is still performed for the whole thick soil layer.The artificial boundary at the bottom of the SSI analysis model is subsequently relocated upward from the bottom of the soil layer(bedrock surface)to the location nearest to the structure as possible.Finally,three types of typical sites and underground structures are adopted with seismic SSI analysis to evaluate the accuracy and efficiency of the proposed efficient analysis scheme.展开更多
Abies fabri is a typical subalpine dark coniferous forest in southwestern China. Air temperature increases more at high elevation areas than that at low elevation areas in mountainous regions,and climate change ratio ...Abies fabri is a typical subalpine dark coniferous forest in southwestern China. Air temperature increases more at high elevation areas than that at low elevation areas in mountainous regions,and climate change ratio is also uneven in different seasons. Carbon gain and the response of water use efficiency(WUE) to annual and seasonal increases in temperature with or without CO_2 fertilization were simulated in Abies fabri using the atmospheric-vegetation interaction model(AVIM2). Four future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5(CMIP5) were selectively investigated. The results showed that warmer temperatures have negative effects on gross primary production(GPP) and net primary production(NPP) in growing seasons and positive effects in dormant seasons due to the variation in the leaf area index. Warmer temperatures tend to generate lower canopy WUE and higher ecosystem WUE in Abies fabri. However,warmer temperature together with rising CO_2 concentrations significantlyincrease the GPP and NPP in both growing and dormant seasons and enhance WUE in annual and dormant seasons because of the higher leaf area index(LAI) and soil temperature. The comparison of the simulated results with and without CO_2 fertilization shows that CO_2 has the potential to partially alleviate the adverse effects of climate warming on carbon gain and WUE in subalpine coniferous forests.展开更多
The Yangtze River Basin’s water resource utilization efficiency(WUE)and scientific and technological innovation level(STI)are closely connected,and the comprehension of these relationships will help to improve WUE an...The Yangtze River Basin’s water resource utilization efficiency(WUE)and scientific and technological innovation level(STI)are closely connected,and the comprehension of these relationships will help to improve WUE and promote local economic growth and conservation of water.This study uses 19 provinces and regions along the Yangtze River’s mainstream from 2009 to 2019 as its research objects and uses a Vector Auto Regression(VAR)model to quantitatively evaluate the spatiotemporal evolution of the coupling coordination degree(CCD)between the two subsystems of WUE and STI.The findings show that:(1)Both the WUE and STI in the Yangtze River Basin showed an upward trend during the study period,but the STI effectively lagged behind the WUE;(2)The CCD of the two subsystems generally showed an upward trend,and the CCD of each province was improved to varying degrees,but the majority of regions did not develop a high-quality coordination stage;(3)The CCD of the two systems displayed apparent positive spatial autocorrelation in the spatial correlation pattern,and there were only two types:high-high(H-H)urbanization areas and low-low(L-L)urbanization areas;(4)The STI showed no obvious response to the impact of the WUE,while the WUE responded greatly to the STI,and both of them were highly dependent on themselves.Optimizing their interaction mechanisms should be the primary focus of high-quality development in the basin of the Yangtze River in the future.These results give the government an empirical basis to enhance the WUE and promote regional sustainable development.展开更多
Deficiency or restriction of Zn absorption in soils is one of the most common micronutrients deficient in cereal plants. To investigate critical micronutrient interaction in zinc deficiency and zinc sufficient in soil...Deficiency or restriction of Zn absorption in soils is one of the most common micronutrients deficient in cereal plants. To investigate critical micronutrient interaction in zinc deficiency and zinc sufficient in soil, a factorial experiment based on completely randomized design (CRD) with three replications was conducted in 2023. Six wheat cultivars with different Zn efficiency were used. The cultivars were grown under Zn deficiency and adequate conditions. Results showed that in Zn deficiency conditions, with increasing Zn concentration in the roots, Fe concentrations were increased too, while the Cu and Mn concentrations decreased. In the same condition and with increasing Zn concentration in shoots, the concentrations of Fe and Mn decreased, while Cu were increased. However, by increasing Zn concentration, Fe, Cu, and Mn concentrations were increased in Zn deficiency condition in grains, as well as Zn sufficient conditions. RST (root to shoot micronutrient translocation) comparison of cultivars showed that in lack of Zn, the ability of translocation of Zn, Fe, and Mn in Zn-inefficient cultivar from root to shoot was higher than inefficient cultivar. In the same conditions, the capability of Zn-inefficient cultivar in Cu translocation from root to shoot was lower than other cultivars. In general, it seems that in Zn deficiency conditions, there are antagonistic effects among Zn, Cu and Mn and synergistic effects between Zn and Fe in the root. Also, in Zn sufficient conditions, there were synergistic effects among all studies micronutrients which include Zn, Fe, Cu, and Mn.展开更多
Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different...Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different octocopter configurations amid hover and forward flight. Conventional and coaxial configurations are studied and a hybrid configuration is also proposed to rectify the disadvantages associated with the earlier two. Comparison is carried out for the aforementioned configurations along with comparison of coaxial and hybrid octocopters with bigger diameter rotors in the same confined space for high thrust requirement missions. Vertical spacing of coaxial configuration is also studied. Virtual Blade Method (VBM) is considered herein due to its great computational efficiency. The results show that there are 11.89% and 14.22% loss in thrust for coaxial octocopter compared to conventional and hybrid configurations with normal size rotors and 15.61% loss compared to hybrid configuration with bigger rotors in hover, whereas coaxial square configuration performs the worst in forward flight with a lift loss of 9.1%, 14.77% and 18.8% compared to coaxial diamond, conventional and hybrid configurations with normal size rotors and 9.96% and 17.82% loss compared to coaxial diamond and hybrid configurations with bigger rotors. Combined FM shows that hybrid configuration outperforms other octocopter configurations in overall aerodynamic performance.展开更多
A coupled PHREEQC-MATLAB simulation approach is proposed to investigate the dynamic changes in rock porosity,gas storage capacity,formation water salinity,and reservoir temperature driven by biogeochemical interaction...A coupled PHREEQC-MATLAB simulation approach is proposed to investigate the dynamic changes in rock porosity,gas storage capacity,formation water salinity,and reservoir temperature driven by biogeochemical interactions during cyclic underground bio-methanation(UBM)of CO_(2)and H_(2),and to quantitatively examine how the evolution of these parameters influences CH_(4)production efficiency.The results indicate that during the cyclic UBM of CO_(2)-H_(2),the formation water undergoes a dynamic acid-base alternation,leading to periodic mineral dissolution and precipitation with limited impact on rock porosity.Across different mineral systems,the maximum CH_(4)production rate remains consistently around 3.6×10^(−3)mol/(L·d)in each cycle.With an increasing number of cycles,under high initial salinity conditions,the metabolic water produced by methanogens can significantly reduce the formation water salinity,gradually enhancing the CH_(4)production rate to levels comparable with those under low initial salinity.Additionally,the increased volume of produced water reduces the gas storage capacity of the reservoir.This reduction becomes more pronounced at higher initial CO_(2)-H_(2)pressures,accompanied by a more significant increase in CH_(4)production rate increment.Furthermore,the heat generated by methanogen metabolism leads to an increase in reservoir temperature,with the extent of temperature rise significantly influenced by heat loss.If the heat loss is neglected,the reservoir temperature can increase by up to 17.1℃after five cycles(10 years).When the reservoir has a higher initial temperature,the elevated thermal conditions may reduce CH_(4)production efficiency.展开更多
氰基化作为一种有效的分子工程策略,能够通过协同的电子效应和空间效应精确调控有机半导体的前线轨道能级与超分子组装行为。本研究设计并合成了一种新型氰基取代的小分子受体NA8,其基于苯并[a]苯嗪核心结构,利用氰基的高极性和线性构...氰基化作为一种有效的分子工程策略,能够通过协同的电子效应和空间效应精确调控有机半导体的前线轨道能级与超分子组装行为。本研究设计并合成了一种新型氰基取代的小分子受体NA8,其基于苯并[a]苯嗪核心结构,利用氰基的高极性和线性构型来增强分子间作用并促进电荷分离。理论与实验结果表明,氰基取代在削弱分子内电荷转移作用(引起吸收蓝移)的同时,显著提升了分子间作用和堆积行为,使NA8表现出相对于中心核无氰基取代的对比分子NA1更高的结晶相干长度。受益于这一分子层面的优化,采用绿色溶剂邻二甲苯制备的PM6:NA8器件实现了19.04%的优异光电转换效率(对比PM6:NA1的15.14%),其性能提升主要归因于更高的短路电流密度(27.35 mA cm^(−2))和填充因子(78.3%)。进一步的原子力显微镜(AFM)、掠入射广角X射线衍射(GIWAXS)和瞬态吸收光谱(TAS)表征证实,NA8基器件的优异性能源于更理想的相分离形貌、更高的载流子迁移率以及更快的激子解离过程。尽管开路电压略有降低(0.889 V vs.0.914 V),这与氰基引入后C–C键振动增强所致的重组能升高相符。综上,核心氰基化为开发兼具高效率与非卤代溶剂加工兼容性的受体材料提供了一条有效途径,并为新一代有机光伏的分子设计提供了参考。展开更多
Microbial consortia are ubiquitous in nature,in which multiple microbial species cooperate to complete some important tasks such as lignocellulose degradation.Because of the advantages such as reduced metabolic burden...Microbial consortia are ubiquitous in nature,in which multiple microbial species cooperate to complete some important tasks such as lignocellulose degradation.Because of the advantages such as reduced metabolic burden and robustness to environment disturbances,developing a microbial consortium is a promising approach for valuable product synthesis,lignocellulose utilization,human health care,bioremediation and sustainable energy,etc.Despite the benefits,however,most artificial microbial consortia confront the problems of instability and low efficiency due to growth competition and metabolite incompatibility.To overcome these challenges,multiple strategies to design efficient synthetic microbial consortia have been reported.In this review,the interactions that determine the stability and performance of microbial consortia were described.Progress of artificial microbial consortia research was summarized,and the key strategies i.e.,spatial or temporal segregation,separated utilization of nutrients,nutrient cross-feeding and division of labor,that will be of great importance for achieving a stable and efficient microbial consortium were highlighted.Two novel advanced tools,signaling molecule systems and computational models,were also introduced and discussed.We believed that combining the universal cell–cell signaling molecule systems with computational models will be promising for synthetic microbial consortia construction in the future.展开更多
基金National Natural Science Foundation of China,No.42371222,No.41971167Fundamental Scientific Research Funds of Central China Normal University,No.CCNU24ZZ120,No.CCNU22JC026。
文摘The efficient development of the urban economy is a major concern of scholars in the fields of geography and urban science.In the context of globalization,informatization,industrialization,and urbanization,the external relationships of China's cities are experiencing the joint action of urban scale hierarchies and connection networks(“hierarchy-network”).However,under the interactive effect of the two,the mechanism of urban economic efficiency(UEE)is unclear.Therefore,based on Baidu migration data,the regionalization with dynamically constrained agglomerative clustering and partitioning(REDCAP)method,and a spatial simultaneous equation model,this paper analyzes the UEE spatial pattern and mechanism in China.The results indicate that:(1)the urban economy has a superlinear relationship with the population size.However,the benefit of this superlinear growth is in marginal decline.(2)The UEE shows a pattern of differentiation between China's eastern,then central,and then western region.Also,local differences are found within the three major sub-regions.(3)The increase of urban network centrality can promote UEE,while the impact of urban scale is negative.(4)There is regional heterogeneity of the interactive effect of“hierarchy-network”on UEE.This study reveals the influencing mechanism of UEE and also provides policy implications for the development of UEE.
基金National Key Research and Development Program of China(2019YFB1600400)National Natural Science Foundation of China(72174035)+2 种基金National Natural Science Foundation of China(71774018)Liaoning Revitalization Talents Program(XLYC2008030)Liaoning Provincial Natural Science Foundation Shipping Joint Foundation Program(2020-HYLH-20)。
文摘It is urgent and important to explore the dynamic evolution in comprehensive transportation green efficiency(CTGE)in the context of green development.We constructed a social development index that reflects the social benefits of transportation services,and incorporated it into the comprehensive transportation efficiency evaluation framework as an expected output.Based on the panel data of 30 regions in China from 2003-2018,the CTGE in China was measured using the slacks-based measure-data envelopment analysis(SBM-DEA)model.Further,the dynamic evolution trends of CTGE were determined using the spatial Markov model and exploratory spatio-temporal data analysis(ESTDA)technique from a spatio-temporal perspective.The results showed that the CTGE shows a U-shaped change trend but with an overall low level and significant regional differences.The state transition of CTGE has a strong spatial dependence,and there exists the phenomenon of“club convergence”.Neighbourhood background has a significant impact on the CTGE transition types,and the spatial spillover effect is pronounced.The CTGE has an obvious positive correlation and spatial agglomeration characteristics.The geometric characteristics of the LISA time path show that the evolution process of local spatial structure and local spatial dependence of China’s CTGE is stable,but the integration of spatial evolution is weak.The spatio-temporal transition results of LISA indicate that the CTGE has obvious transfer inertness and has certain path-dependence and spatial locking characteristics,which will become the major difficulty in improving the CTGE.
文摘The paper mainly presents the design of beam-wave interaction of a C-band high-peakpower high-efficiency broadband klystron.The beam-wave interaction section is designed based on considerations of efficiency and bandwidth synthetically.As a part of beam-wave interaction section,buncher section is simulated by Particle-In-Cell(PIC) code to observe the bunching process of electron beam to achieve high conversion efficiency of electron beam and RF field.When it comes to the other part,output circuit is designed as a three-section filter by an output cavity loaded with Chebyshev filter,and the cold test results are given.The beam-wave interaction is simulated by EGUN code and Arsenal-MSU code respectively.The simulated results indicated that,the existence of power dips in the operating bandwidth is verified by Arsenal-MSU code,comparing proper results by EGUN code.Then,the method that design parameters are not adjusted except parameters of buncher cavities to remove potential power dips is described.What is more,the simulated results of electron optics system are given by EGUN code and Arsenal-MSU code respectively.The further hot test results of klystron prove that the whole design of beam-wave interaction is effective.
基金the National Natural Science Foundation of China(22078051,22478063,22408035)the Fundamental Research Funds for the Central Universities(DUT22-LAB610)the Open Fund of the Key Laboratory of Advanced Display and System Applications,Ministry of Education,Shanghai University(OF202401)for financial support of this work.
文摘Most of acridine based thermally activated delayed fluorescence(TADF)emitters are characterized by advantageous reverse intersystem crossing(RISC)rate(kRISCs)due to the perpendicular orientation of the acridine donor to the acceptor moiety,but suffer from a poor radiation rate(kr)typically in the order of 10^(6) s^(−1).Herein,two sky blue TADF emitters 3,6-DMAC-AD-Py and 3,6-SFAC-AD-Py were developed by linking acridine(DMAC)and spiro-fluorene-acridine(SFAC)donors to 10-(pyridin-2-yl)acridin-9(10H)-one(AD-Py)acceptor.Larger SFAC and electron-deficient pyridyl groups are deliberately incorporated in 3,6-SFACAD-Py since the unique through-space interaction between them is designed to drive the rotation of inner acridine ring in SFAC for enhancing frontier molecular orbitals overlap while keeping a decent TADF behavior.Thus,the kr of 3,6-SFACAD-Py is increased to 1.5×10^(7) s^(−1).Simultaneously,SFAC donors improve spin orbital coupling strength and reduce the energy gaps,generating kRISC of 1.8×10^(6) s^(−1).This is the first acridine donor based TADF emitter realizing kr of 10^(7) s^(−1) and kRISC of 10^(6) s^(−1) by a through-space interaction strategy.3,6-SFACAD-Py enables a highly efficient sky-blue organic light-emitting diode with a maximum external quantum efficiency(EQE)of 34.7%and Commission International de I'Eclairage coordinates of(0.19,0.37).More importantly,the EQE still remained 27.6%and 16.9%at high brightness of 1000 and 10,000 cd m^(−2).
文摘Soybean (Glycine max (L.) Merrill) is one of the most important oil and protein sources in the world. Interactive effect of elevated carbon dioxide (CO2) and soil water availability potentially impact future food security of the world under climate change. A rhizotron growth chamber experiment was conducted to study soil moisture interactions with elevated CO2 on gaseous exchange parameters of soybean under two CO2 concentrations (380 and 800 μmol·mol-1) with three soil moisture levels. Elevated CO2 decreased photosynthetic rate (11.1% and 10.8%), stomatal conductance (40.5% and 36.0%), intercellular CO2 concentration (16.68% and 12.28%), relative intercellular CO2 concentration (17.4% and 11.2%), and transpiration rate (43.6% and 39%) at 42 and 47 DAP. This down-regulation of photosynthesis was probably caused by low leaf nitrogen content and decrease in uptake of nutrients due to decrease in stomatal conductance and transpiration rate. Water use efficiency (WUE) increased under elevated CO2 because increase in total dry weight of plant was greater than that of water use under high CO2 conditions. Plants under normal and high soil moisture levels had significantly higher photosynthetic rate (7% to 16%) favored by optimum soil moisture content and high specific water content of soybean plants. Total dry matter production was significantly high when plants grown under elevated CO2 with normal (74.3% to 137.3%) soil moisture level. Photosynthetic rate was significantly and positively correlated with leaf conductance and intercellular CO2 concentration but WUE was significantly negatively correlated with leaf conductance, intercellular CO2 concentration and transpiration rate. However, the effect of high CO2 on plants depends on availability of nutrients and soil moisture for positive feedback from CO2 enrichment.
基金supported by the Jiangsu Natural Science Foundation of China(Grant No.BK2012477)the Science Research Foundation of Nanjing Institute of Technology(CKJA201505,JCYJ201618)
文摘Adopting a soft site model built on soft interlayer soil foundation,a shaking table test for soft interlayer soil-isolated structure interaction is conducted to investigate the seismic response of isolated structure on soft site,and analyze its isolation effect.Test results show that the test can reflect the earthquake response characteristics of isolated structure on soft site.It is on soft site that the dynamic characteristics of isolated structure,acceleration magnification factor(AMF)of isolated structure and isolation efficiency of the isolation layer differ from those on rigid foundation with an soil-structure interaction(SSI)effect,represented by the reduction in fundamental vibration frequency of isolated structure and the increase of damping ratio with changes of the SSI effect.SSI can either increase or decrease AMF of isolated structure on soft site,depending on the characteristics of earthquake motion input.Furthermore,the isolation efficiency of isolation layer on soft site is decreased with the SSI effect,which is related to the peak ground acceleration(PGA)and the characteristics of earthquake motion input.
基金the Natural Science Foundation of China(11922415,12274471)Guangdong Basic and Applied Basic Research Foundation(2022A1515011168,2019A1515011718,2019A1515011337)the Key Research and Development Program of Guangdong Province,China(2019B110209003).
文摘We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the interface.The interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)RR.This study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.
基金supported by the Natural Science Foundation of China(No.52174232)the Project was supported by Open Research Grant of Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining(Nos.EC2022003 and EC2023005)+1 种基金Anhui University of Science and Technology 2023 Graduate Student Innovation Fund(No.2023cx2106)Open Research Grant of Anhui Engineering Research Center for Coal Clean Processing and Carbon Emission Reduction(No.CCCE-2023003).
文摘This study delves into the intricate relationship between iron(Fe)content in kaolinite and its impact on the adsorption behavior of sodium oleate.The effects of different iron concentrations on adsorption energy,hydrogen bond kinetics and adsorption efficiency were studied through simulation and experimental verification.The results show that the presence of iron in the kaolinite structure significantly improves the adsorption capacity of sodium oleate.Kaolinite samples with high iron content have better adsorption properties,lower adsorption energy levels and shorter and stronger hydrogen bonds than pure kaolinite.The optimal concentration of oleic acid ions for achieving maximum adsorption efficiency was identified as 1.2 mmol/L across different kaolinite samples.At this concentration,the adsorption rates and capacities reach their peak,with Fe-enriched kaolinite samples exhibiting notably higher flotation recovery rates.This optimal concentration represents a balance between sufficient oleic acid ion availability for surface interactions and the prevention of self-aggregation phenomena that could hinder adsorption.This study offers promising avenues for optimizing the flotation process in mineral processing applications.
基金National Basic Research Program of China under Grant No.2015CB057902Ministry of Education Innovation Team of China under Grant No.IRT_17R03National Natural Science Foundation of China under Grant Nos.51421005 and 51678015。
文摘The direct finite element method is a type commonly used for nonlinear seismic soil-structure interaction(SSI)analysis.This method introduces a truncated boundary referred to as an artificial boundary meant to divide the soil-structure system into finite and infinite domains.An artificial boundary condition is used on a truncated boundary to achieve seismic input and simulate the wave radiation effect of infinite domain.When the soil layer is particularly thick,especially for a three-dimensional problem,the computational efficiency of seismic SSI analysis is very low due to the large size of the finite element model,which contains an whole thick soil layer.In this paper,an accurate and efficient scheme is developed to solve the nonlinear seismic SSI problem regarding thick soil layers.The process consists of nonlinear site response and SSI analysis.The nonlinear site response analysis is still performed for the whole thick soil layer.The artificial boundary at the bottom of the SSI analysis model is subsequently relocated upward from the bottom of the soil layer(bedrock surface)to the location nearest to the structure as possible.Finally,three types of typical sites and underground structures are adopted with seismic SSI analysis to evaluate the accuracy and efficiency of the proposed efficient analysis scheme.
基金supported by the Natural Science Foundation of China (No.41401044 and No.41310013)the key research projects of frontier sciences CAS (QYZDJ-SSW-DQC006)+1 种基金the Chinese Academy of Science (‘West Star’ project)the CAS/SAFEA international partnership program for creative research teams (KZZD-EW-TZ-06)
文摘Abies fabri is a typical subalpine dark coniferous forest in southwestern China. Air temperature increases more at high elevation areas than that at low elevation areas in mountainous regions,and climate change ratio is also uneven in different seasons. Carbon gain and the response of water use efficiency(WUE) to annual and seasonal increases in temperature with or without CO_2 fertilization were simulated in Abies fabri using the atmospheric-vegetation interaction model(AVIM2). Four future climate scenarios(RCP2.6,RCP4.5,RCP6.0 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5(CMIP5) were selectively investigated. The results showed that warmer temperatures have negative effects on gross primary production(GPP) and net primary production(NPP) in growing seasons and positive effects in dormant seasons due to the variation in the leaf area index. Warmer temperatures tend to generate lower canopy WUE and higher ecosystem WUE in Abies fabri. However,warmer temperature together with rising CO_2 concentrations significantlyincrease the GPP and NPP in both growing and dormant seasons and enhance WUE in annual and dormant seasons because of the higher leaf area index(LAI) and soil temperature. The comparison of the simulated results with and without CO_2 fertilization shows that CO_2 has the potential to partially alleviate the adverse effects of climate warming on carbon gain and WUE in subalpine coniferous forests.
基金funded by the Humanities and Social Science Research Project of Chongqing Education Commission(23SKJD111)Science and Technology Research Project of Chongqing Education Commission(KJQN202101122 and KJQN201904002)+6 种基金Project of Chongqing Higher Education Association(CQGJ21B057)Chongqing Graduate Education Teaching Reform Research Project(yjg223121)Chongqing Higher Education Teaching Reform Research Project(233337)Higher Education Research Project,Chongqing University of Technology(2022ZD01)Annual project of the“14th Five-Year Plan”for National Business Education in 2022(SKKT-22015)Party Building and Ideological and Political Project,Chongqing University of Technology(2022DJ307)Chongqing University of Technology Undergraduate Education and Teaching Reform Research Project(2021YB21).
文摘The Yangtze River Basin’s water resource utilization efficiency(WUE)and scientific and technological innovation level(STI)are closely connected,and the comprehension of these relationships will help to improve WUE and promote local economic growth and conservation of water.This study uses 19 provinces and regions along the Yangtze River’s mainstream from 2009 to 2019 as its research objects and uses a Vector Auto Regression(VAR)model to quantitatively evaluate the spatiotemporal evolution of the coupling coordination degree(CCD)between the two subsystems of WUE and STI.The findings show that:(1)Both the WUE and STI in the Yangtze River Basin showed an upward trend during the study period,but the STI effectively lagged behind the WUE;(2)The CCD of the two subsystems generally showed an upward trend,and the CCD of each province was improved to varying degrees,but the majority of regions did not develop a high-quality coordination stage;(3)The CCD of the two systems displayed apparent positive spatial autocorrelation in the spatial correlation pattern,and there were only two types:high-high(H-H)urbanization areas and low-low(L-L)urbanization areas;(4)The STI showed no obvious response to the impact of the WUE,while the WUE responded greatly to the STI,and both of them were highly dependent on themselves.Optimizing their interaction mechanisms should be the primary focus of high-quality development in the basin of the Yangtze River in the future.These results give the government an empirical basis to enhance the WUE and promote regional sustainable development.
文摘Deficiency or restriction of Zn absorption in soils is one of the most common micronutrients deficient in cereal plants. To investigate critical micronutrient interaction in zinc deficiency and zinc sufficient in soil, a factorial experiment based on completely randomized design (CRD) with three replications was conducted in 2023. Six wheat cultivars with different Zn efficiency were used. The cultivars were grown under Zn deficiency and adequate conditions. Results showed that in Zn deficiency conditions, with increasing Zn concentration in the roots, Fe concentrations were increased too, while the Cu and Mn concentrations decreased. In the same condition and with increasing Zn concentration in shoots, the concentrations of Fe and Mn decreased, while Cu were increased. However, by increasing Zn concentration, Fe, Cu, and Mn concentrations were increased in Zn deficiency condition in grains, as well as Zn sufficient conditions. RST (root to shoot micronutrient translocation) comparison of cultivars showed that in lack of Zn, the ability of translocation of Zn, Fe, and Mn in Zn-inefficient cultivar from root to shoot was higher than inefficient cultivar. In the same conditions, the capability of Zn-inefficient cultivar in Cu translocation from root to shoot was lower than other cultivars. In general, it seems that in Zn deficiency conditions, there are antagonistic effects among Zn, Cu and Mn and synergistic effects between Zn and Fe in the root. Also, in Zn sufficient conditions, there were synergistic effects among all studies micronutrients which include Zn, Fe, Cu, and Mn.
基金supported by the National Natural Science Foundation of China(No.11972190).
文摘Rotor-to-rotor interaction among neighboring rotors of a multirotor has great significance for aerodynamically efficient multirotor design. Current research is conducted to analyze aerodynamic performance of different octocopter configurations amid hover and forward flight. Conventional and coaxial configurations are studied and a hybrid configuration is also proposed to rectify the disadvantages associated with the earlier two. Comparison is carried out for the aforementioned configurations along with comparison of coaxial and hybrid octocopters with bigger diameter rotors in the same confined space for high thrust requirement missions. Vertical spacing of coaxial configuration is also studied. Virtual Blade Method (VBM) is considered herein due to its great computational efficiency. The results show that there are 11.89% and 14.22% loss in thrust for coaxial octocopter compared to conventional and hybrid configurations with normal size rotors and 15.61% loss compared to hybrid configuration with bigger rotors in hover, whereas coaxial square configuration performs the worst in forward flight with a lift loss of 9.1%, 14.77% and 18.8% compared to coaxial diamond, conventional and hybrid configurations with normal size rotors and 9.96% and 17.82% loss compared to coaxial diamond and hybrid configurations with bigger rotors. Combined FM shows that hybrid configuration outperforms other octocopter configurations in overall aerodynamic performance.
基金Supported by the Horizon Europe Program(101129729)Sichuan Haiju Plan Project(2024JDHJ0012)China Scholarship Council Project(202208080058).
文摘A coupled PHREEQC-MATLAB simulation approach is proposed to investigate the dynamic changes in rock porosity,gas storage capacity,formation water salinity,and reservoir temperature driven by biogeochemical interactions during cyclic underground bio-methanation(UBM)of CO_(2)and H_(2),and to quantitatively examine how the evolution of these parameters influences CH_(4)production efficiency.The results indicate that during the cyclic UBM of CO_(2)-H_(2),the formation water undergoes a dynamic acid-base alternation,leading to periodic mineral dissolution and precipitation with limited impact on rock porosity.Across different mineral systems,the maximum CH_(4)production rate remains consistently around 3.6×10^(−3)mol/(L·d)in each cycle.With an increasing number of cycles,under high initial salinity conditions,the metabolic water produced by methanogens can significantly reduce the formation water salinity,gradually enhancing the CH_(4)production rate to levels comparable with those under low initial salinity.Additionally,the increased volume of produced water reduces the gas storage capacity of the reservoir.This reduction becomes more pronounced at higher initial CO_(2)-H_(2)pressures,accompanied by a more significant increase in CH_(4)production rate increment.Furthermore,the heat generated by methanogen metabolism leads to an increase in reservoir temperature,with the extent of temperature rise significantly influenced by heat loss.If the heat loss is neglected,the reservoir temperature can increase by up to 17.1℃after five cycles(10 years).When the reservoir has a higher initial temperature,the elevated thermal conditions may reduce CH_(4)production efficiency.
文摘氰基化作为一种有效的分子工程策略,能够通过协同的电子效应和空间效应精确调控有机半导体的前线轨道能级与超分子组装行为。本研究设计并合成了一种新型氰基取代的小分子受体NA8,其基于苯并[a]苯嗪核心结构,利用氰基的高极性和线性构型来增强分子间作用并促进电荷分离。理论与实验结果表明,氰基取代在削弱分子内电荷转移作用(引起吸收蓝移)的同时,显著提升了分子间作用和堆积行为,使NA8表现出相对于中心核无氰基取代的对比分子NA1更高的结晶相干长度。受益于这一分子层面的优化,采用绿色溶剂邻二甲苯制备的PM6:NA8器件实现了19.04%的优异光电转换效率(对比PM6:NA1的15.14%),其性能提升主要归因于更高的短路电流密度(27.35 mA cm^(−2))和填充因子(78.3%)。进一步的原子力显微镜(AFM)、掠入射广角X射线衍射(GIWAXS)和瞬态吸收光谱(TAS)表征证实,NA8基器件的优异性能源于更理想的相分离形貌、更高的载流子迁移率以及更快的激子解离过程。尽管开路电压略有降低(0.889 V vs.0.914 V),这与氰基引入后C–C键振动增强所致的重组能升高相符。综上,核心氰基化为开发兼具高效率与非卤代溶剂加工兼容性的受体材料提供了一条有效途径,并为新一代有机光伏的分子设计提供了参考。
基金This work was supported by the National Key R&D Program of China(2018YFA0902200)National Natural Science Foundation of China(No.21776157No.22078173).
文摘Microbial consortia are ubiquitous in nature,in which multiple microbial species cooperate to complete some important tasks such as lignocellulose degradation.Because of the advantages such as reduced metabolic burden and robustness to environment disturbances,developing a microbial consortium is a promising approach for valuable product synthesis,lignocellulose utilization,human health care,bioremediation and sustainable energy,etc.Despite the benefits,however,most artificial microbial consortia confront the problems of instability and low efficiency due to growth competition and metabolite incompatibility.To overcome these challenges,multiple strategies to design efficient synthetic microbial consortia have been reported.In this review,the interactions that determine the stability and performance of microbial consortia were described.Progress of artificial microbial consortia research was summarized,and the key strategies i.e.,spatial or temporal segregation,separated utilization of nutrients,nutrient cross-feeding and division of labor,that will be of great importance for achieving a stable and efficient microbial consortium were highlighted.Two novel advanced tools,signaling molecule systems and computational models,were also introduced and discussed.We believed that combining the universal cell–cell signaling molecule systems with computational models will be promising for synthetic microbial consortia construction in the future.
