We propose a novel fast numerical calculation method for the Rayleigh-Sommerfeld diffraction integral,which is developed based on the existing scaled convolution method.This approach enables fast cal-culations for gen...We propose a novel fast numerical calculation method for the Rayleigh-Sommerfeld diffraction integral,which is developed based on the existing scaled convolution method.This approach enables fast cal-culations for general cases of off-axis scenarios where the sampling intervals and numbers of the input and observation planes are unequal.Additionally,it allows for arbitrary adjustment of the sampling interval of the impulse response function,facilitating a manual trade-off between computational load and accuracy.The er-rors associated with this method,which is equivalent to interpolation,primarily arise from the discontinuities of the sampling matrix of the impulse response function on its boundaries of periodic extension.To address this issue,we propose the concept of the padding function and its construction method,and evaluate its ef-fectiveness in enhancing computational accuracy.The feasibility of the proposed method is verified by nu-merical simulation and compared with the direct integration DI-method in a simplified scenario.It shows that the proposed method has good computational accuracy for the general case where the sampling interval of the input and observation plane is not equal under non-near-field diffraction,and when the diffraction distance is large,although the computational accuracy of the proposed method cannot exceed that of the DI-method,the computational amount can be significantly reduced with almost no effect on the computational accuracy.This method provides a general numerical calculation scheme of diffraction in the non-near field case for areas such as computational holography.展开更多
Arbitration is a key non-litigation commercial mechanism for the resolution of disputes, and the quality and credibility of its awards depend largely on the competency of the arbitrators. However, the selection and ev...Arbitration is a key non-litigation commercial mechanism for the resolution of disputes, and the quality and credibility of its awards depend largely on the competency of the arbitrators. However, the selection and evaluation systems for arbitrators in China have long faced challenges such as the vague criteria for competency and an unclear professionalization path for arbitrators. To address these issues, this study is grounded in the context of actual Chinese arbitration practice and based on the competency iceberg model. Through a methodological approach encompassing literature reviews, behavioral event interviews, expert revisions, and questionnaire surveys, a Chinese Arbitrator Competency Scale was developed and validated in this study. Examination of the findings indicated that the scale needed to consist of five dimensions—communication and coordination, cognitive skills, ethical conduct, work motivation, and personality traits—and possess a total of 28 specific indicators. Confirmatory analysis of the factors demonstrates a good fit for the five-dimensional model, with each of the dimensions exhibiting high reliability and validity. This scale is innovative in integrating the competency elements with Chinese characteristics, such as commercial acumen, crosscultural mediation skills, and adaptability to the local rule of law. This research not only enriches the competency theory in regard to the field of human resource management but also provides a scientific framework of standards and measurement tools for the selection, training, and evaluation of arbitrators. It thus has significant practical value for enhancing the professionalism and international competitiveness of China's arbitration system.展开更多
Among the low-cost nitrogen sources(dry spent yeast or DSY,rice bran,and soybean meal),DSY was identified as the most suitable supplement for lactic acid fermentation from sweet sorghum juice by Lactococcus lactis IO-...Among the low-cost nitrogen sources(dry spent yeast or DSY,rice bran,and soybean meal),DSY was identified as the most suitable supplement for lactic acid fermentation from sweet sorghum juice by Lactococcus lactis IO-1.However,lactic acid concentration(PL)using DSY was~22%lower than the control nitrogen source,yeast extract(YE).Statistical analysis using YE as a control nitrogen source revealed optimal conditions of 74.70 g/L of initial sugar and 15.20 g/L of YE,achieving a PL of 71.95 g/L and a 91.63%sugar consumption(SC).When DSY(22.61 g/L)containing an equivalent nitrogen content to the optimal YE was tested,PL and SC decreased to 55.13 g/L and 72.33%,respectively.Increasing DSY to 33.92 g/L(1.5 times)improved lactic acid productivity(QL)by~31%but did not enhance PL or SC.However,supplementing 33.92 g/L of DSY with 7.60 g/L of YE enhanced lactic acid production by~19-53%,achieving a PL of 70.11 g/L,SC of 92.33%,QL of 2.34 g/L⋅h,with a high lactic acid yield(YL/S),1.02 g/g.Scale-up fermentation in a 7.5-L fermenter demonstrated comparable results to those using 15.20 g/L of YE alone.These findings demonstrate that sweet sorghum juice supplemented with DSY and reduced YE is a promising medium for efficient lactic acid production,offering significant cost reduction potential for industrial applications while maintaining high productivity and yield.展开更多
Investigating urban spatial structures(USSs)and their influencing factors at different spatial scales is crucial for promoting sustainable urban transformation.Based on nighttime light datasets and the Herfindahl-Hirs...Investigating urban spatial structures(USSs)and their influencing factors at different spatial scales is crucial for promoting sustainable urban transformation.Based on nighttime light datasets and the Herfindahl-Hirschman index(HHI),this study analyzes USS characteristics in China from 2007 to 2023 on two spatial scales-prefecture-level cities and urban agglomerations.It also explores structural influencing factors,including the economy,infrastructure,society,and government intervention.We find that:(1)HHI values for both cities and urban agglomerations exhibit a decreasing trend,indicating a USS for both that is evolving toward polycentricity;(2)economic development promotes a polycentric structure at both spatial scales,whereas government intervention drives a monocentric structure;and(3)postal and communication infrastructure have conflicting effects on USSs,encouraging a monocentric structure at the city scale but fostering polycentricity at the urban agglomeration scale.展开更多
Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefor...Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development.展开更多
Thermal storage electric heating(TSEH),as a prevalent variable load resource,offers significant potential for enhancing system flexibility when aggregated into a cluster.To address the uncertainties of renewable energ...Thermal storage electric heating(TSEH),as a prevalent variable load resource,offers significant potential for enhancing system flexibility when aggregated into a cluster.To address the uncertainties of renewable energy and load forecasting in active distribution networks(ADN),this paper proposes a multi-timescale coordinated optimal dispatch strategy that incorporates TSEH clusters.It utilizes the thermal storage characteristics and short-term regulation capabilities of TSEH,along with the rapid and gradual response characteristics of resources in active distribution grids,to develop a coordinated optimization dispatch mechanism for day-ahead,intraday,and real-time stages.It provides a coordinated optimized dispatch technique across several timescales for active distribution grids,taking into account the integration of TSEH clusters.The proposed method is validated on a modified IEEE 33-node system.Simulation results demonstrate that the participation of TSEH in collaborative optimization significantly reduces the total system operating cost by 8.71%compared to the scenario without TSEH.This cost reduction is attributed to a 10.84%decrease in interaction costs with the main grid and a 47.41%reduction in network loss costs,validating effective peak shaving and valley filling.The multi-timescale framework further enhances economic efficiency,with overall operating costs progressively decreasing by 3.91%(intraday)and 4.59%(real-time),and interaction costs further reduced by 5.34%and 9.25%,respectively.Moreover,the approach enhances system stability by effectively suppressing node voltage fluctuations and ensuring all voltages remain within safe operating limits during real-time operation.Therefore,the proposed approach achieves rational coordination of diverse resources,significantly improving the economic efficiency and stability of ADNs.展开更多
Northeast China serves as an important crop production region.Accurately forecasting summer precipitation in Northeast China(NEC-PR)has been a challenge due to its wide range of time scales influenced by varying clima...Northeast China serves as an important crop production region.Accurately forecasting summer precipitation in Northeast China(NEC-PR)has been a challenge due to its wide range of time scales influenced by varying climatic conditions.This study presents a scale separation hybrid statistical model with recurrent neural network(SS-RNN)to predict the summer monthly NEC-PR.The SS-RNN model decomposes the multiple scales of the NEC-PR into several spatiotemporal intrinsic mode functions covering annual to decadal time scales.This strategy provides a way to derive appropriate predictors and establish predictive models for the primary spatial modes of the NEC-PR at various time scales.Our results demonstrate substantial improvements by the SS-RNN model in predicting the summer monthly NEC-PR as compared with dynamic models,particularly in predicting the spatial pattern of the NEC-PR.In this paper we take August,the month of the highest NEC-PR,to assess our model skill.Independent forecasts of the August NEC-PR over the period 2021–24 achieve significant spatial anomaly correlation coefficients,reaching a maximum value of 0.83.Additional verifications by station observations show that the model hits most station anomalies,achieving a mean predictive skill score of 90.展开更多
The Kibble-Zurek (KZ) effect offers an overarching description of dynamical scaling behavior near a critical point.[1,2] Originally proposed in a classical setup,the KZ effect has been generalized to quantum phase tra...The Kibble-Zurek (KZ) effect offers an overarching description of dynamical scaling behavior near a critical point.[1,2] Originally proposed in a classical setup,the KZ effect has been generalized to quantum phase transitions[3-5] and is actively explored on quantum simulation platforms.[6-9] Exploring how the KZ effect fares across different criticalities has proven to be a rewarding pursuit,significantly enriching our understanding of nonequilibrium quantum dynamics.[3-5,10-23]展开更多
The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailabi...The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailability of large-area substrates,limiting studies to small-scale samples.Leveraging the recent emergence of 2-inch wafers,we report the first demonstration of homoepitaxial growth on a 2-inch,Fe-doped semi-insulating(010)β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition(MOCVD).A systematic,wafer-scale characterization reveals the successful growth of a highquality epitaxial film.High-resolution x-ray diffraction shows an excellent crystalline structure,with a rocking curve full-width ranging from 21.0 arcsec to 103.0 arcsec.Atomic force microscopy confirms an atomically smooth surface with a root-mean-square roughness below 1.53 nm,displaying a distinct step-flow growth mode across the wafer.Furthermore,mercury-probe capacitance-voltage mapping indicates a well-controlled carrier concentration of~2×10~(18)cm~(-3)with a RSD of 5.12%.This work provides the first comprehensive assessment of 2-inch(010)Ga_(2)O_(3)epitaxial wafers,validating a critical material platform for the development and future manufacturing of high-performance power devices.展开更多
Among the charged leptons,theτelectric dipole moment dτis the least constrained.We show that the Im[d_(τ)]imposes strong constraints on new physics that have yet to be discussed.Motivated in particular by the Super...Among the charged leptons,theτelectric dipole moment dτis the least constrained.We show that the Im[d_(τ)]imposes strong constraints on new physics that have yet to be discussed.Motivated in particular by the Super Tau-Charm Facility(STCF),which will provide a uniquely clean environment for precisionτ-physics,we study the momentum-transfer dependence of d_(τ)(q^(2))and compare the projected sensitivities of STCF and BelleⅡ.Our analysis shows that an axion-like coupling of the τ lepton can induce sizable real and imaginary components of the EDM.The predicted EDM values may approach the present experimental sensitivities,making them accessible to future measurements at Belle II and the STCF.展开更多
Based on the concepts of fast polarization, effective electric field and electron impact ionization criterion, the effect of polymer type on electric breakdown strength （EBD） on a nanosecond time scale is investigat...Based on the concepts of fast polarization, effective electric field and electron impact ionization criterion, the effect of polymer type on electric breakdown strength （EBD） on a nanosecond time scale is investigated, and a formula that qualitatively characterizes the relation between the electric breakdown strength and the polymer type is derived. According to this formula, it is found that the electric breakdown strength decreases with an increase in the effective relative dielectric constants of the polymers. By calculating the effective relative dielectric constants for different types of polymers, the theoretical relation for the electric breakdown strengths of common polymers is predicted. To verify the prediction, the polymers of PE （polyethylene）, PTFE （polytetrafluoroethelene）, PMMA （organic glass） and Nylon are tested with a nanosecond-pulse generator. The experimental result shows EBD （PTFE） 〉 EBD （PMMA） 〉 EBD （Nylon） 〉 EBD （PE）. This result is consistent with the theoretical prediction.展开更多
Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Tai...Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Taizhou Bridge is arranged to investigate the effects of non-uniform ground motion input, collision between main and side spans and optimal seismic structural system. It's very important and difficult to design and manufacture the scaled down model of Taizhou Bridge used during the shaking table test. The key point is that the girder and pylons are very hard to be manufactured if the similarity ratio is strictly followed. Based on the finite element method (FEM) analysis, a simplified scaled down model is designed and the bending stiffness of the girder and pylon are strictly simulated, and the torsion stiffness and axial stiffness are not strictly simulated. The inner forces and displacements of critical sections, points of simplified model and theoretical model are compared by FEM analysis, and it's found out that the difference between the seismic responses is relatively small. So, the simplified model can be used to conduct the shaking table test by the FEM verification.展开更多
A down-scaled operational oceanographic system is developed for the coastal waters of Korea using a re- gional ocean modeling system （ROMS）. The operational oceanographic modeling system consists of at- mospheric an...A down-scaled operational oceanographic system is developed for the coastal waters of Korea using a re- gional ocean modeling system （ROMS）. The operational oceanographic modeling system consists of at- mospheric and hydrodynamic models. The hydrodynamic model, ROMS, is coupled with wave, sediment transport, and water quality modules. The system forecasts the predicted results twice a day on a 72 h basis, including sea surface elevation, currents, temperature, salinity, storm surge height, and wave information for the coastal waters of Korea. The predicted results are exported to the web-GIS-based coastal informa- tion system for real-time dissemination to the public and validation with real-time monitoring data using visualization technologies. The ROMS is two-way coupled with a simulating waves nearshore model, SWAN, for the hydrodynamics and waves, nested with the meteorological model, WRE for the atmospheric surface forcing, and externally nested with the eutrophication model, CE-QUAL-ICM, for the water quality. The op- erational model, ROMS, was calibrated with the tidal surface observed with a tide-gage and verified with current data observed by bottom-mounted ADCP or AWAC near the coastal waters of Korea. To validate the predicted results, we used real-time monitoring data derived from remote buoy system, HF-radar, and geostationary ocean color imager （GOCI）. This down-scaled operational coastal forecasting system will be used as a part of the Korea operational oceanographic system （KOOS） with other operational oceanographic systems.展开更多
Bioprocess scale-down simulators are used to investigate the phenomena occurring in industrial scale cultivations. The aim is to simulate the large-scale conditions, characterized by long mixing times introducing loca...Bioprocess scale-down simulators are used to investigate the phenomena occurring in industrial scale cultivations. The aim is to simulate the large-scale conditions, characterized by long mixing times introducing local gradients into the bioreactor, in laboratory scale bioreactor. We have expanded the current physiological knowledge about the consequences of such cultivation conditions from well-known mixed-acid fermentation to amino acid metabolism. Several interesting deviations were observed for amino acids derived from pyruvate when a STR-PFR scale-down simulator and a regular STR fed-batch cultivation were compared. In this article we show that the cultivation of Escherichia coli K-12 substrain W3110 in a scale-down two-compartment bioreactor has consequences on the free amino acid pools. Repeated occurrence of high glucose zones affects the biosynthesis of amino acids derived from pyruvate. This is interesting since the pyruvate based amino acids are precursors of the branched chain amino acid pathway, which is further disturbed by an unbalanced regulation caused by a frameshift mutation in the ilvG gene of E. coli K-12 strains. As a consequence the formation of non-typical amino acid norvaline was detected in the two compartment bioreactor cultivation.展开更多
This paper presents the results of a comprehensive study of water scale found in water distribution system of Taliouine city in the south of Morocco. Physico-chemical properties of drinking water supplied to the city ...This paper presents the results of a comprehensive study of water scale found in water distribution system of Taliouine city in the south of Morocco. Physico-chemical properties of drinking water supplied to the city were evaluated. The data showed a high level of soluble salt in water. Concentrations were calcium 108 - 143 mg/1, magnesium 80 - 96 mg/1, bicarbonate 660 - 750 mg/l and hardness degree 660 - 690 mg CaCO3/l. The water samples contain high amounts of minerals in the form of ions, especially the metals calcium and bicarbonate, which precipitated out and caused problems in water conducting or storing vessels like pipes. Scales were removed from the inside of two old pipes which transported drinking and hot water in the downtown of Taliouine city. Scale samples were investigated by XRF, XRD, SEM, DTA, TGA and SEM’s analytical techniques. This study was able to identify scales formed in pipes of water distribution systems. It was found that water scale in this city contains 53% of calcium oxide and 43% of organic matter. The XRD and SEM results revealed that calcite was the main crystalline structure in drinking water scale. Nevertheless, scale deposited in hot water pipe is well crystalline with peaks corresponding mostly to aragonite (88%) along with calcite (12%). The thermal behavior of scale samples confirms that calcium carbonate was the main compound in the scale samples. Further studies are needed to find an efficient antiscale in drinking water of this city.展开更多
When a wind turbine is struck by lightning,its blades are usually rotating.The effect of blade rotation on a turbine＇s ability to trigger a lightning strike is unclear.Therefore,an arching electrode was used in a win...When a wind turbine is struck by lightning,its blades are usually rotating.The effect of blade rotation on a turbine＇s ability to trigger a lightning strike is unclear.Therefore,an arching electrode was used in a wind turbine lightning discharge test to investigate the difference in lightning triggering ability when blades are rotating and stationary.A negative polarity switching waveform of 250/2500 μs was applied to the arching electrode and the up-and-down method was used to calculate the 50%discharge voltage.Lightning discharge tests of a 1：30 scale wind turbine model with 2,4,and 6 m air gaps were performed and the discharge process was observed.The experimental results demonstrated that when a 2 m air gap was used,the breakdown voltage increased as the blade speed was increased,but when the gap length was 4 m or longer,the trend was reversed and the breakdown voltage decreased.The analysis revealed that the rotation of the blades changes the charge distribution in the blade-tip region,promotes upward leader development on the blade tip,and decreases the breakdown voltage.Thus,the blade rotation of a wind turbine increases its ability to trigger lightning strikes.展开更多
The scale effect on shear strength of rock joints is well-documented.However,whether scale effects are negative,positive,or even exist or not is still controversial.Joint roughness significantly influences the shear s...The scale effect on shear strength of rock joints is well-documented.However,whether scale effects are negative,positive,or even exist or not is still controversial.Joint roughness significantly influences the shear strength of rock joints.Compared to the shear tests,using the joint roughness coefficient(JRC)and its roughness parameters offers a more convenient method for describing the scale effect on shear strength.However,it is crucial to understand that the scale effect mechanisms of JRC are distinct from those of shear strength.Therefore,this paper aims to clarify these distinct mechanisms.By digitally extracting roughness parameters from granite samples,it is found that the scale effect of roughness parameters mainly comes from the sampling methods and the geometric characteristics of parameters.Furthermore,a full data sampling method considering heterogeneity is proposed to obtain more representative roughness parameters.To reveal the scale effect mechanisms of shear strength,Gaussian filtering is firstly used to separate the waviness and unevenness components of roughness,facilitating a deeper understanding of the geometric characteristics of roughness.It is suggested that the wavelength of the waviness component can reflect the scale effect on shear strength.Secondly,numerical simulations of ideal artificial joint models are conducted to validate that the wavelength of the waviness component serves as the dividing point between positive and negative scale effects.The mechanical mechanisms of positive and negative scale effects are also interpreted.Finally,these mechanisms successfully elucidate the occurrence patterns of the scale effect on natural joint profiles.展开更多
An improved model based on you only look once version 8(YOLOv8)is proposed to solve the problem of low detection accuracy due to the diversity of object sizes in optical remote sensing images.Firstly,the feature pyram...An improved model based on you only look once version 8(YOLOv8)is proposed to solve the problem of low detection accuracy due to the diversity of object sizes in optical remote sensing images.Firstly,the feature pyramid network(FPN)structure of the original YOLOv8 mode is replaced by the generalized-FPN(GFPN)structure in GiraffeDet to realize the"cross-layer"and"cross-scale"adaptive feature fusion,to enrich the semantic information and spatial information on the feature map to improve the target detection ability of the model.Secondly,a pyramid-pool module of multi atrous spatial pyramid pooling(MASPP)is designed by using the idea of atrous convolution and feature pyramid structure to extract multi-scale features,so as to improve the processing ability of the model for multi-scale objects.The experimental results show that the detection accuracy of the improved YOLOv8 model on DIOR dataset is 92%and mean average precision(mAP)is 87.9%,respectively 3.5%and 1.7%higher than those of the original model.It is proved the detection and classification ability of the proposed model on multi-dimensional optical remote sensing target has been improved.展开更多
文摘We propose a novel fast numerical calculation method for the Rayleigh-Sommerfeld diffraction integral,which is developed based on the existing scaled convolution method.This approach enables fast cal-culations for general cases of off-axis scenarios where the sampling intervals and numbers of the input and observation planes are unequal.Additionally,it allows for arbitrary adjustment of the sampling interval of the impulse response function,facilitating a manual trade-off between computational load and accuracy.The er-rors associated with this method,which is equivalent to interpolation,primarily arise from the discontinuities of the sampling matrix of the impulse response function on its boundaries of periodic extension.To address this issue,we propose the concept of the padding function and its construction method,and evaluate its ef-fectiveness in enhancing computational accuracy.The feasibility of the proposed method is verified by nu-merical simulation and compared with the direct integration DI-method in a simplified scenario.It shows that the proposed method has good computational accuracy for the general case where the sampling interval of the input and observation plane is not equal under non-near-field diffraction,and when the diffraction distance is large,although the computational accuracy of the proposed method cannot exceed that of the DI-method,the computational amount can be significantly reduced with almost no effect on the computational accuracy.This method provides a general numerical calculation scheme of diffraction in the non-near field case for areas such as computational holography.
基金Research on Problems and Countermeasures in Building the Capacity of the Grassroots International Chambers of Commerce in the Context of High-Quality Development (W2024H03841)a key research project of the China Council for the Promotion of International Trade in 2025。
文摘Arbitration is a key non-litigation commercial mechanism for the resolution of disputes, and the quality and credibility of its awards depend largely on the competency of the arbitrators. However, the selection and evaluation systems for arbitrators in China have long faced challenges such as the vague criteria for competency and an unclear professionalization path for arbitrators. To address these issues, this study is grounded in the context of actual Chinese arbitration practice and based on the competency iceberg model. Through a methodological approach encompassing literature reviews, behavioral event interviews, expert revisions, and questionnaire surveys, a Chinese Arbitrator Competency Scale was developed and validated in this study. Examination of the findings indicated that the scale needed to consist of five dimensions—communication and coordination, cognitive skills, ethical conduct, work motivation, and personality traits—and possess a total of 28 specific indicators. Confirmatory analysis of the factors demonstrates a good fit for the five-dimensional model, with each of the dimensions exhibiting high reliability and validity. This scale is innovative in integrating the competency elements with Chinese characteristics, such as commercial acumen, crosscultural mediation skills, and adaptability to the local rule of law. This research not only enriches the competency theory in regard to the field of human resource management but also provides a scientific framework of standards and measurement tools for the selection, training, and evaluation of arbitrators. It thus has significant practical value for enhancing the professionalism and international competitiveness of China's arbitration system.
基金supported by Research Program Funding,from Research and Innovation Department,Khon Kaen University(RP68-6-FerVAAP-001),ThailandThe authors also thank Beer Thip Brewery Co.,Ltd.,Phra Nakhon Si Ayutthaya,Thailand for providing dried spent yeast(DSY).
文摘Among the low-cost nitrogen sources(dry spent yeast or DSY,rice bran,and soybean meal),DSY was identified as the most suitable supplement for lactic acid fermentation from sweet sorghum juice by Lactococcus lactis IO-1.However,lactic acid concentration(PL)using DSY was~22%lower than the control nitrogen source,yeast extract(YE).Statistical analysis using YE as a control nitrogen source revealed optimal conditions of 74.70 g/L of initial sugar and 15.20 g/L of YE,achieving a PL of 71.95 g/L and a 91.63%sugar consumption(SC).When DSY(22.61 g/L)containing an equivalent nitrogen content to the optimal YE was tested,PL and SC decreased to 55.13 g/L and 72.33%,respectively.Increasing DSY to 33.92 g/L(1.5 times)improved lactic acid productivity(QL)by~31%but did not enhance PL or SC.However,supplementing 33.92 g/L of DSY with 7.60 g/L of YE enhanced lactic acid production by~19-53%,achieving a PL of 70.11 g/L,SC of 92.33%,QL of 2.34 g/L⋅h,with a high lactic acid yield(YL/S),1.02 g/g.Scale-up fermentation in a 7.5-L fermenter demonstrated comparable results to those using 15.20 g/L of YE alone.These findings demonstrate that sweet sorghum juice supplemented with DSY and reduced YE is a promising medium for efficient lactic acid production,offering significant cost reduction potential for industrial applications while maintaining high productivity and yield.
基金supported by the National Natural Science Foundation of China[Grant No.72373084]Taishan Scholar Foundation of Shandong Province[Grant No.tsqn202408139].
文摘Investigating urban spatial structures(USSs)and their influencing factors at different spatial scales is crucial for promoting sustainable urban transformation.Based on nighttime light datasets and the Herfindahl-Hirschman index(HHI),this study analyzes USS characteristics in China from 2007 to 2023 on two spatial scales-prefecture-level cities and urban agglomerations.It also explores structural influencing factors,including the economy,infrastructure,society,and government intervention.We find that:(1)HHI values for both cities and urban agglomerations exhibit a decreasing trend,indicating a USS for both that is evolving toward polycentricity;(2)economic development promotes a polycentric structure at both spatial scales,whereas government intervention drives a monocentric structure;and(3)postal and communication infrastructure have conflicting effects on USSs,encouraging a monocentric structure at the city scale but fostering polycentricity at the urban agglomeration scale.
基金Under the auspices of the National Natural Science Foundation of China(No.42371222,41971167)Fundamental Scientific Research Funds of Central China Normal University(No.CCNU24ZZ120)。
文摘Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development.
基金supported by Integrated Distribution Network Planning and Operational Enhancement Using Flexibility Domains Under Deep Human-Vehicle-Charger-Road-Grid Coupling(U22B20105).
文摘Thermal storage electric heating(TSEH),as a prevalent variable load resource,offers significant potential for enhancing system flexibility when aggregated into a cluster.To address the uncertainties of renewable energy and load forecasting in active distribution networks(ADN),this paper proposes a multi-timescale coordinated optimal dispatch strategy that incorporates TSEH clusters.It utilizes the thermal storage characteristics and short-term regulation capabilities of TSEH,along with the rapid and gradual response characteristics of resources in active distribution grids,to develop a coordinated optimization dispatch mechanism for day-ahead,intraday,and real-time stages.It provides a coordinated optimized dispatch technique across several timescales for active distribution grids,taking into account the integration of TSEH clusters.The proposed method is validated on a modified IEEE 33-node system.Simulation results demonstrate that the participation of TSEH in collaborative optimization significantly reduces the total system operating cost by 8.71%compared to the scenario without TSEH.This cost reduction is attributed to a 10.84%decrease in interaction costs with the main grid and a 47.41%reduction in network loss costs,validating effective peak shaving and valley filling.The multi-timescale framework further enhances economic efficiency,with overall operating costs progressively decreasing by 3.91%(intraday)and 4.59%(real-time),and interaction costs further reduced by 5.34%and 9.25%,respectively.Moreover,the approach enhances system stability by effectively suppressing node voltage fluctuations and ensuring all voltages remain within safe operating limits during real-time operation.Therefore,the proposed approach achieves rational coordination of diverse resources,significantly improving the economic efficiency and stability of ADNs.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3002803)the National Key Research and Development Program of China(Grant No.2024YFF0808402)the National Natural Science Foundation of China(Grant No.42375169)。
文摘Northeast China serves as an important crop production region.Accurately forecasting summer precipitation in Northeast China(NEC-PR)has been a challenge due to its wide range of time scales influenced by varying climatic conditions.This study presents a scale separation hybrid statistical model with recurrent neural network(SS-RNN)to predict the summer monthly NEC-PR.The SS-RNN model decomposes the multiple scales of the NEC-PR into several spatiotemporal intrinsic mode functions covering annual to decadal time scales.This strategy provides a way to derive appropriate predictors and establish predictive models for the primary spatial modes of the NEC-PR at various time scales.Our results demonstrate substantial improvements by the SS-RNN model in predicting the summer monthly NEC-PR as compared with dynamic models,particularly in predicting the spatial pattern of the NEC-PR.In this paper we take August,the month of the highest NEC-PR,to assess our model skill.Independent forecasts of the August NEC-PR over the period 2021–24 achieve significant spatial anomaly correlation coefficients,reaching a maximum value of 0.83.Additional verifications by station observations show that the model hits most station anomalies,achieving a mean predictive skill score of 90.
文摘The Kibble-Zurek (KZ) effect offers an overarching description of dynamical scaling behavior near a critical point.[1,2] Originally proposed in a classical setup,the KZ effect has been generalized to quantum phase transitions[3-5] and is actively explored on quantum simulation platforms.[6-9] Exploring how the KZ effect fares across different criticalities has proven to be a rewarding pursuit,significantly enriching our understanding of nonequilibrium quantum dynamics.[3-5,10-23]
基金supported by the National Natural Science Foundation of China(Grant Nos.U23A20358,62474170,61925110,62404214,and 62234007)the University of Science and Technology of China(USTC)Research Funds of the Double First-Class Initiative(Grant No.WK2100000055)+2 种基金the Project of the 46t hResearch Institute of CETC(Grant No.WDZC202446007)the JieBang Headed Project of Changsha City Hunan Province(Grant No.kq2301006)the Opening Project and the Key Laboratory of Nano devices and Applications in Suzhou Institute of Nano-Tech and NanoBionics of CAS。
文摘The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailability of large-area substrates,limiting studies to small-scale samples.Leveraging the recent emergence of 2-inch wafers,we report the first demonstration of homoepitaxial growth on a 2-inch,Fe-doped semi-insulating(010)β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition(MOCVD).A systematic,wafer-scale characterization reveals the successful growth of a highquality epitaxial film.High-resolution x-ray diffraction shows an excellent crystalline structure,with a rocking curve full-width ranging from 21.0 arcsec to 103.0 arcsec.Atomic force microscopy confirms an atomically smooth surface with a root-mean-square roughness below 1.53 nm,displaying a distinct step-flow growth mode across the wafer.Furthermore,mercury-probe capacitance-voltage mapping indicates a well-controlled carrier concentration of~2×10~(18)cm~(-3)with a RSD of 5.12%.This work provides the first comprehensive assessment of 2-inch(010)Ga_(2)O_(3)epitaxial wafers,validating a critical material platform for the development and future manufacturing of high-performance power devices.
基金supported by the National Natural Science Foundation of China (Grant Nos.12090064,12205063,12375088,and W2441004)the Fundamental Research Funds for the Central Universitiesin part by the National Key Research and Development Program of China (Grant No.2020YFC2201501)。
文摘Among the charged leptons,theτelectric dipole moment dτis the least constrained.We show that the Im[d_(τ)]imposes strong constraints on new physics that have yet to be discussed.Motivated in particular by the Super Tau-Charm Facility(STCF),which will provide a uniquely clean environment for precisionτ-physics,we study the momentum-transfer dependence of d_(τ)(q^(2))and compare the projected sensitivities of STCF and BelleⅡ.Our analysis shows that an axion-like coupling of the τ lepton can induce sizable real and imaginary components of the EDM.The predicted EDM values may approach the present experimental sensitivities,making them accessible to future measurements at Belle II and the STCF.
文摘Based on the concepts of fast polarization, effective electric field and electron impact ionization criterion, the effect of polymer type on electric breakdown strength （EBD） on a nanosecond time scale is investigated, and a formula that qualitatively characterizes the relation between the electric breakdown strength and the polymer type is derived. According to this formula, it is found that the electric breakdown strength decreases with an increase in the effective relative dielectric constants of the polymers. By calculating the effective relative dielectric constants for different types of polymers, the theoretical relation for the electric breakdown strengths of common polymers is predicted. To verify the prediction, the polymers of PE （polyethylene）, PTFE （polytetrafluoroethelene）, PMMA （organic glass） and Nylon are tested with a nanosecond-pulse generator. The experimental result shows EBD （PTFE） 〉 EBD （PMMA） 〉 EBD （Nylon） 〉 EBD （PE）. This result is consistent with the theoretical prediction.
基金National Science and Technology Support Program of China(No.2009BAG15B01)Key Programs for Science and Technology Development of Chinese Transportation Industry(No.2008-353-332-190)+2 种基金Natural Science Foundation of China(No.50708074)the Ministry of Science and Technology of China(No.SLDRCE08-B-04)Kwang-Hua Fund for College of Civil Engineering,Tongji University
文摘Taizhou Bridge is the first kilometer level three-pylon two-span suspension bridge in the world and the structural complexity has significant effects on the seismic performance of the bridge. Shaking table test of Taizhou Bridge is arranged to investigate the effects of non-uniform ground motion input, collision between main and side spans and optimal seismic structural system. It's very important and difficult to design and manufacture the scaled down model of Taizhou Bridge used during the shaking table test. The key point is that the girder and pylons are very hard to be manufactured if the similarity ratio is strictly followed. Based on the finite element method (FEM) analysis, a simplified scaled down model is designed and the bending stiffness of the girder and pylon are strictly simulated, and the torsion stiffness and axial stiffness are not strictly simulated. The inner forces and displacements of critical sections, points of simplified model and theoretical model are compared by FEM analysis, and it's found out that the difference between the seismic responses is relatively small. So, the simplified model can be used to conduct the shaking table test by the FEM verification.
基金The project entitled Cooperation on the Development of Basic Technologies for the Yellow Sea and East China Sea Operational Oceanographic System funded by the China-Korea Joint Ocean Research Centerthe project entitled"Development of Korea Operational Oceanographic System"funded by the Ministry of Oceans and Fisheries,Koreathe project Functional Improvement of Korea Ocean Satellite Center and Development of the Marine Environment Impact Prediction Program funded by the Korea Institute of Ocean Science and Technology
文摘A down-scaled operational oceanographic system is developed for the coastal waters of Korea using a re- gional ocean modeling system （ROMS）. The operational oceanographic modeling system consists of at- mospheric and hydrodynamic models. The hydrodynamic model, ROMS, is coupled with wave, sediment transport, and water quality modules. The system forecasts the predicted results twice a day on a 72 h basis, including sea surface elevation, currents, temperature, salinity, storm surge height, and wave information for the coastal waters of Korea. The predicted results are exported to the web-GIS-based coastal informa- tion system for real-time dissemination to the public and validation with real-time monitoring data using visualization technologies. The ROMS is two-way coupled with a simulating waves nearshore model, SWAN, for the hydrodynamics and waves, nested with the meteorological model, WRE for the atmospheric surface forcing, and externally nested with the eutrophication model, CE-QUAL-ICM, for the water quality. The op- erational model, ROMS, was calibrated with the tidal surface observed with a tide-gage and verified with current data observed by bottom-mounted ADCP or AWAC near the coastal waters of Korea. To validate the predicted results, we used real-time monitoring data derived from remote buoy system, HF-radar, and geostationary ocean color imager （GOCI）. This down-scaled operational coastal forecasting system will be used as a part of the Korea operational oceanographic system （KOOS） with other operational oceanographic systems.
文摘Bioprocess scale-down simulators are used to investigate the phenomena occurring in industrial scale cultivations. The aim is to simulate the large-scale conditions, characterized by long mixing times introducing local gradients into the bioreactor, in laboratory scale bioreactor. We have expanded the current physiological knowledge about the consequences of such cultivation conditions from well-known mixed-acid fermentation to amino acid metabolism. Several interesting deviations were observed for amino acids derived from pyruvate when a STR-PFR scale-down simulator and a regular STR fed-batch cultivation were compared. In this article we show that the cultivation of Escherichia coli K-12 substrain W3110 in a scale-down two-compartment bioreactor has consequences on the free amino acid pools. Repeated occurrence of high glucose zones affects the biosynthesis of amino acids derived from pyruvate. This is interesting since the pyruvate based amino acids are precursors of the branched chain amino acid pathway, which is further disturbed by an unbalanced regulation caused by a frameshift mutation in the ilvG gene of E. coli K-12 strains. As a consequence the formation of non-typical amino acid norvaline was detected in the two compartment bioreactor cultivation.
文摘This paper presents the results of a comprehensive study of water scale found in water distribution system of Taliouine city in the south of Morocco. Physico-chemical properties of drinking water supplied to the city were evaluated. The data showed a high level of soluble salt in water. Concentrations were calcium 108 - 143 mg/1, magnesium 80 - 96 mg/1, bicarbonate 660 - 750 mg/l and hardness degree 660 - 690 mg CaCO3/l. The water samples contain high amounts of minerals in the form of ions, especially the metals calcium and bicarbonate, which precipitated out and caused problems in water conducting or storing vessels like pipes. Scales were removed from the inside of two old pipes which transported drinking and hot water in the downtown of Taliouine city. Scale samples were investigated by XRF, XRD, SEM, DTA, TGA and SEM’s analytical techniques. This study was able to identify scales formed in pipes of water distribution systems. It was found that water scale in this city contains 53% of calcium oxide and 43% of organic matter. The XRD and SEM results revealed that calcite was the main crystalline structure in drinking water scale. Nevertheless, scale deposited in hot water pipe is well crystalline with peaks corresponding mostly to aragonite (88%) along with calcite (12%). The thermal behavior of scale samples confirms that calcium carbonate was the main compound in the scale samples. Further studies are needed to find an efficient antiscale in drinking water of this city.
基金supported by the China State Grid Corp headquarters project in 2015(SGTYHT/14JS-188)
文摘When a wind turbine is struck by lightning,its blades are usually rotating.The effect of blade rotation on a turbine＇s ability to trigger a lightning strike is unclear.Therefore,an arching electrode was used in a wind turbine lightning discharge test to investigate the difference in lightning triggering ability when blades are rotating and stationary.A negative polarity switching waveform of 250/2500 μs was applied to the arching electrode and the up-and-down method was used to calculate the 50%discharge voltage.Lightning discharge tests of a 1：30 scale wind turbine model with 2,4,and 6 m air gaps were performed and the discharge process was observed.The experimental results demonstrated that when a 2 m air gap was used,the breakdown voltage increased as the blade speed was increased,but when the gap length was 4 m or longer,the trend was reversed and the breakdown voltage decreased.The analysis revealed that the rotation of the blades changes the charge distribution in the blade-tip region,promotes upward leader development on the blade tip,and decreases the breakdown voltage.Thus,the blade rotation of a wind turbine increases its ability to trigger lightning strikes.
基金funded by the National Natural Science Foundation Projects(Grant Nos.41772287 and 42277132)the Key R&D Project of Zhejiang Province(Grant No.2021C03159).
文摘The scale effect on shear strength of rock joints is well-documented.However,whether scale effects are negative,positive,or even exist or not is still controversial.Joint roughness significantly influences the shear strength of rock joints.Compared to the shear tests,using the joint roughness coefficient(JRC)and its roughness parameters offers a more convenient method for describing the scale effect on shear strength.However,it is crucial to understand that the scale effect mechanisms of JRC are distinct from those of shear strength.Therefore,this paper aims to clarify these distinct mechanisms.By digitally extracting roughness parameters from granite samples,it is found that the scale effect of roughness parameters mainly comes from the sampling methods and the geometric characteristics of parameters.Furthermore,a full data sampling method considering heterogeneity is proposed to obtain more representative roughness parameters.To reveal the scale effect mechanisms of shear strength,Gaussian filtering is firstly used to separate the waviness and unevenness components of roughness,facilitating a deeper understanding of the geometric characteristics of roughness.It is suggested that the wavelength of the waviness component can reflect the scale effect on shear strength.Secondly,numerical simulations of ideal artificial joint models are conducted to validate that the wavelength of the waviness component serves as the dividing point between positive and negative scale effects.The mechanical mechanisms of positive and negative scale effects are also interpreted.Finally,these mechanisms successfully elucidate the occurrence patterns of the scale effect on natural joint profiles.
基金supported by the National Natural Science Foundation of China(No.62241109)the Tianjin Science and Technology Commissioner Project(No.20YDTPJC01110)。
文摘An improved model based on you only look once version 8(YOLOv8)is proposed to solve the problem of low detection accuracy due to the diversity of object sizes in optical remote sensing images.Firstly,the feature pyramid network(FPN)structure of the original YOLOv8 mode is replaced by the generalized-FPN(GFPN)structure in GiraffeDet to realize the"cross-layer"and"cross-scale"adaptive feature fusion,to enrich the semantic information and spatial information on the feature map to improve the target detection ability of the model.Secondly,a pyramid-pool module of multi atrous spatial pyramid pooling(MASPP)is designed by using the idea of atrous convolution and feature pyramid structure to extract multi-scale features,so as to improve the processing ability of the model for multi-scale objects.The experimental results show that the detection accuracy of the improved YOLOv8 model on DIOR dataset is 92%and mean average precision(mAP)is 87.9%,respectively 3.5%and 1.7%higher than those of the original model.It is proved the detection and classification ability of the proposed model on multi-dimensional optical remote sensing target has been improved.
