To address the global climate crisis,achieving energy transitions is imperative.Establishing a new-type power system is a key measure to achieve CO_(2) emissions peaking and carbon neutrality.The core goal is to trans...To address the global climate crisis,achieving energy transitions is imperative.Establishing a new-type power system is a key measure to achieve CO_(2) emissions peaking and carbon neutrality.The core goal is to transform renewable energy resources into primary power sources.The large-scale integration of high proportions of renewable energy sources and power electronic devices will dramatically change the operational mechanisms and control strategies of power systems.Existing wind and solar converters mostly adopt the grid-following control mode,which leads to significant challenges in system security and stability as it is insufficient to support the frequency and voltage of the grid.On the other hand,grid-forming control technology(GFM)can provide voltage and frequency support for the system,and thus becomes an effective measure to improve the inertia and damping characteristics of power systems.This paper illustrates the principles,control strategies,equipment types,application scenarios,and project implementation of grid-forming technology.The simulation and analysis based on a renewable-dominated real new-type power system show that GFM can significantly enhance the frequency and voltage support capacity of the power system,improve renewable energy accommodation capacity and grid transmission capacity under weak grid conditions,and play an important role in enhancing the stability and power supply reliability of renewable-dominated new-type power systems.展开更多
Computational Intelligence (CI) holds the key to the development of smart grid to overcome the challenges of planning and optimization through accurate prediction of Renewable Energy Sources (RES). This paper presents...Computational Intelligence (CI) holds the key to the development of smart grid to overcome the challenges of planning and optimization through accurate prediction of Renewable Energy Sources (RES). This paper presents an architectural framework for the construction of hybrid intelligent predictor for solar power. This research investigates the applicability of heterogeneous regression algorithms for 6 hour ahead solar power availability forecasting using historical data from Rockhampton, Australia. Real life solar radiation data is collected across six years with hourly resolution from 2005 to 2010. We observe that the hybrid prediction method is suitable for a reliable smart grid energy management. Prediction reliability of the proposed hybrid prediction method is carried out in terms of prediction error performance based on statistical and graphical methods. The experimental results show that the proposed hybrid method achieved acceptable prediction accuracy. This potential hybrid model is applicable as a local predictor for any proposed hybrid method in real life application for 6 hours in advance prediction to ensure constant solar power supply in the smart grid operation.展开更多
To study the wind vibration response of power transmission tower, the lead viscoelastic dampers （LVDs） were applied to a cup tower. With time history analysis method, the displacement, velocity, acceleration and for...To study the wind vibration response of power transmission tower, the lead viscoelastic dampers （LVDs） were applied to a cup tower. With time history analysis method, the displacement, velocity, acceleration and force response of the tower was calculated and analyzed. The results show that the control effect of lead viscoelastic dampers is very good, and the damping ratio can reach 20% or more when they are applied to the tower head.展开更多
Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of ele...Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of electric energy. In this paper the author studies the development scale, development schedule, accommodation and transmission schemes of the cascade hydropower stations along the Lancang River basin, one of the five large basins in China, based on the load characteristics of grids at both the sending end and the receiving end, the strategy of complementary utilization of thermal power and hydropower, the advanced transmission technologies, and the optimal economic performance. The study results show that, the cascade hydropower stations on the upper reaches of the Lancang River in Yunnan should mainly serve Guangdong Province, with proper planning of partly serving Yunnan Province during dry seasons. The transmission schemes should adopt UHVDC, UHVAC, and single-tower double-circuited HVDC transmission scheme according to the transmission capacity and distance.展开更多
The uneven distribution of economic development and energy resources in the Southern Power Grid, yet with stronger complementary superiority has determined the necessity to actively push forward power transmission fro...The uneven distribution of economic development and energy resources in the Southern Power Grid, yet with stronger complementary superiority has determined the necessity to actively push forward power transmission from west to east in the Southern Power Grid and realize optimal disposition in even greater scope. To further promote transmission capability and operational security from west to east, measures including power sources disposition, unit starting schemes, power grid configuration, DC modulation and application of new transmission technologies are analyzed in this paper.展开更多
For highway engineering construction, foundation is very important, especially the project is located in soft soil foundation. Corresponding measures must be taken according to the specific situation to ensure the sta...For highway engineering construction, foundation is very important, especially the project is located in soft soil foundation. Corresponding measures must be taken according to the specific situation to ensure the stability of subgrade. However, in the construction of modern highway engineering, the soft soil foundation is generally unstable, which affects the quality of highway materials. It can be seen that in order to promote highway engineering orderly and ensure its quality and safety, highway engineering construction units must change the existing construction mode, so as to promote the vigorous development of highway engineering.展开更多
Advanced oxidation processes are promising for degradation of the highly chemical stability and refractory methylisothiazolinone(MIT) bactericides in relevant industrial wastewater.In order to assemble a low cost and ...Advanced oxidation processes are promising for degradation of the highly chemical stability and refractory methylisothiazolinone(MIT) bactericides in relevant industrial wastewater.In order to assemble a low cost and high performance electrochemical oxidation system for wastewater treatment,granular active carbon(GAC) was decorated by doping Ce,Sn,Sb to synthesize Sn-Sb-Ce/GAC using sol-gel method as particle electrode filled into a three-dimensional(3D) electrochemical reactor.Scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS) and X-ray diffraction(XRD) experiments revealed that the Sn-Sb-Ce/GAC particle electrode crystal particles were compact and uniform,and the surface structure was improved.The ten cyclic experiments indicated that the Sn-Sb-Ce/GAC particle electrode had high stability and low dissolution of the loaded active substance.The degradation mechanism of MIT was studied under the optimal working conditions of 3D electrode system with GAC of 5 g/L,current density of 20 mA/cm^(2),initial pH 5,electrolyte concentration of Na_(2)SO_(4)0.02 mol/L and reaction time of 120 min.The indirect electrochemical degradation of MIT was dominated by active substance pathway that active chlorine rather than free radicals(·OH) played the main role.Comparing with conventional two-dimensional(2D) electrode system,the 3D electrochemical system has larger active electrode area,higher treatment efficiency and lower energy consumption than the former.The 3D electrochemical system could remove 96.5% of MIT from the actual high-salt reverse osmosis concentrate wastewater in 30 min.It has a certain removal effect on UV_(254)in wastewater,but has a better removal effect on fluorescent substances.This study proposed a new strategy to develop transition metal and rare earth metal particle electrodes using carbon-based materials for high efficient electrocatalytic oxidation in the electrochemical treatment system.展开更多
Accurate short-term forecast of offshore wind fields is still challenging for numerical weather prediction models.Based on three years of 48-hour forecast data from the European Centre for Medium-Range Weather Forecas...Accurate short-term forecast of offshore wind fields is still challenging for numerical weather prediction models.Based on three years of 48-hour forecast data from the European Centre for Medium-Range Weather Forecasts Integrated Forecasting System global model(ECMWF-IFS)over 14 offshore weather stations along the coast of Shandong Province,this study introduces a multi-task learning(MTL)model(TabNet-MTL),which significantly improves the forecast bias of near-surface wind direction and speed simultaneously.TabNet-MTL adopts the feature engineering method,utilizes mean square error as the loss function,and employs the 5-fold cross validation method to ensure the generalization ability of the trained model.It demonstrates superior skills in wind field correction across different forecast lead times over all stations compared to its single-task version(TabNet-STL)and three other popular single-task learning models(Random Forest,LightGBM,and XGBoost).Results show that it significantly reduces root mean square error of the ECMWF-IFS wind speed forecast from 2.20 to 1.25 m s−1,and increases the forecast accuracy of wind direction from 50%to 65%.As an explainable deep learning model,the weather stations and long-term temporal statistics of near-surface wind speed are identified as the most influential variables for TabNet-MTL in constructing its feature engineering.展开更多
The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the Kmeans algorithm depends highly on initial cluster centers and converges to local minima. This paper prop...The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the Kmeans algorithm depends highly on initial cluster centers and converges to local minima. This paper proposes a hybrid evolutionary programming based clustering algorithm, called PSO-SA, by combining particle swarm optimization (PSO) and simulated annealing (SA). The basic idea is to search around the global solution by SA and to increase the information exchange among particles using a mutation operator to escape local optima. Three datasets, Iris, Wisconsin Breast Cancer, and Ripley's Glass, have been considered to show the effectiveness of the proposed clustering algorithm in providing optimal clusters. The simulation results show that the PSO-SA clustering algorithm not only has a better response but also converges more quickly than the K-means, PSO, and SA algorithms.展开更多
In perennially frozen or seasonally frozen soil regions,freeze-thaw cycling adversely impacts the mechanical properties of rock mass,resulting in landslides,rock erosion,and other geological disasters.The microscopic ...In perennially frozen or seasonally frozen soil regions,freeze-thaw cycling adversely impacts the mechanical properties of rock mass,resulting in landslides,rock erosion,and other geological disasters.The microscopic damage evolution law of loaded sandstone under the freeze-thaw cycle is analyzed by conducting Nuclear Magnetic Resonance(NMR)and uniaxial compression acoustic emission(AE)experiments.The experimental results have shown that:(1)Freeze-thaw cycling increases sandstone's internal pores,enlarges the pore size,and modifies the original pore distribution.(2)The damage due to freeze-thaw cycling is positively correlated with the initial damage to the rock,and the damage on the rock surface is more severe than inside the rock sample.(3)Freeze-thaw cycling negatively impacts the mechanical properties of sandstone,and the elastic deformation stage of sandstone gradually decreases as the number of freeze-thaw cycles increases and gradually transitions from brittle failure to ductile failure.(4)The characteristic parameters of AE ringing count and accumulated energy can reveal the severity of freeze-thaw damage and the dynamic evolution process,and the damage development rate exhibits abrupt changes at critical moments.After five freeze-thaw cycles,the damage development rate rises suddenly,as manifested by a sharp increase in the frequency and energy of AE events.High-energy AE events frequently occur during the rapid expansion period of damage,which can be adopted as an essential reference for damage propagation and aggravation.展开更多
The surface trap parameter can significantly affect the development of surface flashover in vacuum,but the effective mode and mechanism are not very clear yet.The trap parameters of three polymeric materials were test...The surface trap parameter can significantly affect the development of surface flashover in vacuum,but the effective mode and mechanism are not very clear yet.The trap parameters of three polymeric materials were tested and calculated by means of isothermal surface potential decay.The flashover experiment was developed under different applied voltages.The results show a positive correlation between the withstand voltage and the deep trap,i.e.,the deeper trap energy level is,the higher flashover voltage is.The dynamics process of charge trapping and detrapping was analyzed based on the charge transport model in dielectrics with a single trap level and two discrete trap levels.The time of charge trapping was compared with that of the discharge development.The results show that the charge trapping time is longer than the flashover development time.The way to influence flashover for a trap is not to decrease the secondary electrons in single discharge development,but to change the electric field distribution on the dielectric surface by charge capture.展开更多
Weak structural surface is one of the key factors controlling the stability of slopes. The stability of rock slopes is in general concerned with set of discontinuities. However, in soft rocks, failure can occur along ...Weak structural surface is one of the key factors controlling the stability of slopes. The stability of rock slopes is in general concerned with set of discontinuities. However, in soft rocks, failure can occur along surfaces approaching to a circular failure surface. To better understand the position of potential sliding surface, a new method called simplex-finite stochastic tracking method is proposed. This method basically divides sliding surface into two parts： one is described by smooth curve obtained by random searching, the other one is po｜yline formed by the weak structural surface. Single or multiple sliding surfaces can be considered, and consequently several types of combined sliding surfaces can be simu- lated. The paper will adopt the arc-polyline to simulate potential sliding surface and analyze the searching process of sliding surface. Accordingly, software for slope stability analysis using this method was developed and applied in real cases. The results show that, using simplex-finite stochastic tracking method, it is possible to locate the position of a potential sliding surface in the slope.展开更多
In the multi-wave and multi-component seismic exploration,shear-wave will be split into fast wave and slow wave,when it propagates in anisotropic media. Then the authors can predict polarization direction and density ...In the multi-wave and multi-component seismic exploration,shear-wave will be split into fast wave and slow wave,when it propagates in anisotropic media. Then the authors can predict polarization direction and density of crack and detect the development status of cracks underground according to shear-wave splitting phenomenon. The technology plays an important role and shows great potential in crack reservoir detection. In this study,the improved particle swarm optimization algorithm based on shrinkage factor is combined with the Pearson correlation coefficient method to obtain the fracture azimuth angle and density. The experimental results show that the modified method can improve the convergence rate,accuracy,anti-noise performance and computational efficiency.展开更多
Inclusion of textures in image classification has been shown beneficial.This paper studies an efficient use of semivariogram features for object-based high-resolution image classification.First,an input image is divid...Inclusion of textures in image classification has been shown beneficial.This paper studies an efficient use of semivariogram features for object-based high-resolution image classification.First,an input image is divided into segments,for each of which a semivariogram is then calculated.Second,candidate features are extracted as a number of key locations of the semivariogram functions.Then we use an improved Relief algorithm and the principal component analysis to select independent and significant features.Then the selected prominent semivariogram features and the conventional spectral features are combined to constitute a feature vector for a support vector machine classifier.The effect of such selected semivariogram features is compared with those of the gray-level co-occurrence matrix(GLCM)features and window-based semivariogram texture features(STFs).Tests with aerial and satellite images show that such selected semivariogram features are of a more beneficial supplement to spectral features.The described method in this paper yields a higher classification accuracy than the combination of spectral and GLCM features or STFs.展开更多
This study takes a fractured rock mass in the Datengxia Hydropower Station,China as an example to analyze the size effects and determine the representative elementary sizes.A novel method considering geometric paramet...This study takes a fractured rock mass in the Datengxia Hydropower Station,China as an example to analyze the size effects and determine the representative elementary sizes.A novel method considering geometric parameter distributions is proposed in this work.The proposed method can quickly and simply determine the size effects and representative elementary sizes.Specifically,geometric parameter distributions,including fracture frequency,size and orientation,are generated on the basis of the Bernoulli trial and Monte Carlo simulation.The distributions are assessed using the coefficient of variation(CV),and the acceptable variations for CV(5%,10%and 20%)are used to determine representative elementary sizes.Generally,the representative element of rock masses is the representative elementary volume(REV).The present study extends the representative element to other dimensions,i.e.representative elementary length(REL)and representative elementary area(REA)for one and two dimensions,respectively.REL and REA are useful in studying the size effects of one-(1D)and twodimensional(2D)characteristics of rock masses.The relationships among multi-dimensional representative elementary sizes are established.The representative elementary sizes reduce with the increase in the dimensions,and REA and REV can be deduced by REL.Therefore,the proposed method can quickly and simply determine REL and further estimate REA and REV,which considerably improves the efficiency of rock mass analysis.展开更多
South and north-dipping nodal planes from the U.S. Geological Survey moment tensor solution were used to invert global teleseismic body waves to reveal the source rupture process of the December 8, 2016, Mw6.0 Hutubi ...South and north-dipping nodal planes from the U.S. Geological Survey moment tensor solution were used to invert global teleseismic body waves to reveal the source rupture process of the December 8, 2016, Mw6.0 Hutubi earthquake. The results show that a compact pattern is the main feature of this event for only one main slip zone located at the hypocenter for both models, The slip distributions are dominated by a nearly pure-thrust fault, and there is no apparent surface rupture. The inversion revealed that the slip zone extends 10 km along strike and 12 km along dip. The released total seismic moment was about 9.0 -1017 Nm, corresponding to a magnitude of Mw6.0. It is difficult to solve for a best-fit rupture plane due to the sample slip pattern without obvious rupture directivity. This makes the far- field teleseismic data not sensitive enough to determine the fault geometric parameters. The source model of the reverse north-dipping plane fits well with the observed waveforms, and the results of the aftershock relocation outline a trend of north-dipping profiles, indicating the possibility of a reverse event. The inverted normal fault beneath the Qigu fold, interpreted by geological and seismic studies, may be the seismogenic fault for this reverse event.展开更多
Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for...Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA （volatile fatty acid） in a shorter time can be achieved at pH 10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supematant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.展开更多
The permafrost development in the Qinghai-Tibet Engineering Corridor(QTEC)is affected by natural environment changes and human engineering activities.Human engineering activities may damage the permafrost growing envi...The permafrost development in the Qinghai-Tibet Engineering Corridor(QTEC)is affected by natural environment changes and human engineering activities.Human engineering activities may damage the permafrost growing environment,which in turn impact these engineering activities.Thus high spatial-temporal resolution monitoring over the QTEC in the permafrost region is very necessary.This paper presents a method for monitoring the frozen soil area using the intermittent coherencebased small baseline subset(ICSBAS).The method can improve the point density of the results and enhance the interpretability of deformation results by identifying the discontinuous coherent points according to the coherent value of time series.Using the periodic function that models the seasonal variation of permafrost,we separate the long wavelength atmospheric delay and establish an estimation model for the frozen soil deformation.Doing this can raise the monitoring accuracy and improve the understanding of the surface deformation of the frozen soil.In this study,we process 21 PALSAR data acquired by the Alos satellite with the proposed ICSBAS technique.The results show that the frozen soil far from the QTR in the study area experiences frost heave and thaw settlement(4.7 cm to8.4 cm)alternatively,while the maximum settlement along the QTR reaches 12 cm.The interferomatric syntnetic aperture radar(InSAR)-derived results are validated using the ground leveling data nearby the Beiluhe basin.The validation results show the InSAR results have good consistency with the leveling data in displacement rates as well as time series.We also find that the deformation in the permafrost area is correlated with temperature,human activities and topography.Based on the interfering degree of human engineering activities on the permafrost environment,we divide the QTEC along the Qinghai-Tibet Railway into engineering damage zone,transition zone and natural permafrost.展开更多
Spiking deconvolution is a standard Wiener Levinson algorithm. The autocorrelation of the design time gate is computed and there is a specified taper on the design gate before the autoeorrelation is done. The standard...Spiking deconvolution is a standard Wiener Levinson algorithm. The autocorrelation of the design time gate is computed and there is a specified taper on the design gate before the autoeorrelation is done. The standard equations are set up, prewhitening is added to the zero lag value of the autocorrelation and the matrix is inverted to derive the spiking operator. In this study, the authors describe a technique for performing spiking deconvolution on prestack time migration （PSTM） data, to test the effect of operator length and percent prewhitening in spiking deconvolution and apply spiking deconvolution trace by trace, with operator lengths 15ms, 10 ms and 5 ms when percent prewhitening 0% , 40ms and 60ms for percent prewhitening 1%. The results show when prewhitening is 0% the shorter operator gives better results, but when value of prewhitening is bigger than 0% it is better to use longer operator lengths.展开更多
文摘To address the global climate crisis,achieving energy transitions is imperative.Establishing a new-type power system is a key measure to achieve CO_(2) emissions peaking and carbon neutrality.The core goal is to transform renewable energy resources into primary power sources.The large-scale integration of high proportions of renewable energy sources and power electronic devices will dramatically change the operational mechanisms and control strategies of power systems.Existing wind and solar converters mostly adopt the grid-following control mode,which leads to significant challenges in system security and stability as it is insufficient to support the frequency and voltage of the grid.On the other hand,grid-forming control technology(GFM)can provide voltage and frequency support for the system,and thus becomes an effective measure to improve the inertia and damping characteristics of power systems.This paper illustrates the principles,control strategies,equipment types,application scenarios,and project implementation of grid-forming technology.The simulation and analysis based on a renewable-dominated real new-type power system show that GFM can significantly enhance the frequency and voltage support capacity of the power system,improve renewable energy accommodation capacity and grid transmission capacity under weak grid conditions,and play an important role in enhancing the stability and power supply reliability of renewable-dominated new-type power systems.
文摘Computational Intelligence (CI) holds the key to the development of smart grid to overcome the challenges of planning and optimization through accurate prediction of Renewable Energy Sources (RES). This paper presents an architectural framework for the construction of hybrid intelligent predictor for solar power. This research investigates the applicability of heterogeneous regression algorithms for 6 hour ahead solar power availability forecasting using historical data from Rockhampton, Australia. Real life solar radiation data is collected across six years with hourly resolution from 2005 to 2010. We observe that the hybrid prediction method is suitable for a reliable smart grid energy management. Prediction reliability of the proposed hybrid prediction method is carried out in terms of prediction error performance based on statistical and graphical methods. The experimental results show that the proposed hybrid method achieved acceptable prediction accuracy. This potential hybrid model is applicable as a local predictor for any proposed hybrid method in real life application for 6 hours in advance prediction to ensure constant solar power supply in the smart grid operation.
基金Research Fund of Chinese State Grid Company (No.SGKJ[2007]413)
文摘To study the wind vibration response of power transmission tower, the lead viscoelastic dampers （LVDs） were applied to a cup tower. With time history analysis method, the displacement, velocity, acceleration and force response of the tower was calculated and analyzed. The results show that the control effect of lead viscoelastic dampers is very good, and the damping ratio can reach 20% or more when they are applied to the tower head.
文摘Most of the hydropower projects in Southwest China and the adjacent foreign regions will be put into operation between 2015 and 2020, which will bring some difficulties for reasonable accommodation and delivery of electric energy. In this paper the author studies the development scale, development schedule, accommodation and transmission schemes of the cascade hydropower stations along the Lancang River basin, one of the five large basins in China, based on the load characteristics of grids at both the sending end and the receiving end, the strategy of complementary utilization of thermal power and hydropower, the advanced transmission technologies, and the optimal economic performance. The study results show that, the cascade hydropower stations on the upper reaches of the Lancang River in Yunnan should mainly serve Guangdong Province, with proper planning of partly serving Yunnan Province during dry seasons. The transmission schemes should adopt UHVDC, UHVAC, and single-tower double-circuited HVDC transmission scheme according to the transmission capacity and distance.
文摘The uneven distribution of economic development and energy resources in the Southern Power Grid, yet with stronger complementary superiority has determined the necessity to actively push forward power transmission from west to east in the Southern Power Grid and realize optimal disposition in even greater scope. To further promote transmission capability and operational security from west to east, measures including power sources disposition, unit starting schemes, power grid configuration, DC modulation and application of new transmission technologies are analyzed in this paper.
文摘For highway engineering construction, foundation is very important, especially the project is located in soft soil foundation. Corresponding measures must be taken according to the specific situation to ensure the stability of subgrade. However, in the construction of modern highway engineering, the soft soil foundation is generally unstable, which affects the quality of highway materials. It can be seen that in order to promote highway engineering orderly and ensure its quality and safety, highway engineering construction units must change the existing construction mode, so as to promote the vigorous development of highway engineering.
基金the financial supports from Major Science and Technology project of China Power Engineering Consulting Group Co., Ltd. "Research on Green and digital Intelligent Technology of Sewage Treatment Plant" (No. CEEC2023-ZDYF-09)Technology Innovation Ability Improvement Project of Shandong Province, China (No. 2022TSGC1247)。
文摘Advanced oxidation processes are promising for degradation of the highly chemical stability and refractory methylisothiazolinone(MIT) bactericides in relevant industrial wastewater.In order to assemble a low cost and high performance electrochemical oxidation system for wastewater treatment,granular active carbon(GAC) was decorated by doping Ce,Sn,Sb to synthesize Sn-Sb-Ce/GAC using sol-gel method as particle electrode filled into a three-dimensional(3D) electrochemical reactor.Scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS) and X-ray diffraction(XRD) experiments revealed that the Sn-Sb-Ce/GAC particle electrode crystal particles were compact and uniform,and the surface structure was improved.The ten cyclic experiments indicated that the Sn-Sb-Ce/GAC particle electrode had high stability and low dissolution of the loaded active substance.The degradation mechanism of MIT was studied under the optimal working conditions of 3D electrode system with GAC of 5 g/L,current density of 20 mA/cm^(2),initial pH 5,electrolyte concentration of Na_(2)SO_(4)0.02 mol/L and reaction time of 120 min.The indirect electrochemical degradation of MIT was dominated by active substance pathway that active chlorine rather than free radicals(·OH) played the main role.Comparing with conventional two-dimensional(2D) electrode system,the 3D electrochemical system has larger active electrode area,higher treatment efficiency and lower energy consumption than the former.The 3D electrochemical system could remove 96.5% of MIT from the actual high-salt reverse osmosis concentrate wastewater in 30 min.It has a certain removal effect on UV_(254)in wastewater,but has a better removal effect on fluorescent substances.This study proposed a new strategy to develop transition metal and rare earth metal particle electrodes using carbon-based materials for high efficient electrocatalytic oxidation in the electrochemical treatment system.
基金the National Key Research and Development Plan of China[Grant No.2023YFB3002400]the Shanghai 2021 Natural Science Foundation[Grant Nos.21ZR1420400 and 21ZR1419800]+1 种基金the Shanghai 2023 Natural Science Foundation[Grant No.23ZR1463000]the Shandong Provincial Meteorological Bureau Scientific Research Project[Grant No.2023SDBD05].
文摘Accurate short-term forecast of offshore wind fields is still challenging for numerical weather prediction models.Based on three years of 48-hour forecast data from the European Centre for Medium-Range Weather Forecasts Integrated Forecasting System global model(ECMWF-IFS)over 14 offshore weather stations along the coast of Shandong Province,this study introduces a multi-task learning(MTL)model(TabNet-MTL),which significantly improves the forecast bias of near-surface wind direction and speed simultaneously.TabNet-MTL adopts the feature engineering method,utilizes mean square error as the loss function,and employs the 5-fold cross validation method to ensure the generalization ability of the trained model.It demonstrates superior skills in wind field correction across different forecast lead times over all stations compared to its single-task version(TabNet-STL)and three other popular single-task learning models(Random Forest,LightGBM,and XGBoost).Results show that it significantly reduces root mean square error of the ECMWF-IFS wind speed forecast from 2.20 to 1.25 m s−1,and increases the forecast accuracy of wind direction from 50%to 65%.As an explainable deep learning model,the weather stations and long-term temporal statistics of near-surface wind speed are identified as the most influential variables for TabNet-MTL in constructing its feature engineering.
文摘The K-means algorithm is one of the most popular techniques in clustering. Nevertheless, the performance of the Kmeans algorithm depends highly on initial cluster centers and converges to local minima. This paper proposes a hybrid evolutionary programming based clustering algorithm, called PSO-SA, by combining particle swarm optimization (PSO) and simulated annealing (SA). The basic idea is to search around the global solution by SA and to increase the information exchange among particles using a mutation operator to escape local optima. Three datasets, Iris, Wisconsin Breast Cancer, and Ripley's Glass, have been considered to show the effectiveness of the proposed clustering algorithm in providing optimal clusters. The simulation results show that the PSO-SA clustering algorithm not only has a better response but also converges more quickly than the K-means, PSO, and SA algorithms.
基金Project supported by the National Natural Science Foundation of China(No.51378057)the National Basic Research Program(973Program)of China(No.2012CB026104)the Fund of the NorthChina Power Engineering Co.,Ltd.of China Power Engineering Consulting Group(No.C14L01530),China
基金supported by the National Natural Science Foundation of China(42277172,42177144,42077274,51774231,41702339)Funded by the Natural Science Basic Research Program of Shaanxi Province(2020JZ-53).
文摘In perennially frozen or seasonally frozen soil regions,freeze-thaw cycling adversely impacts the mechanical properties of rock mass,resulting in landslides,rock erosion,and other geological disasters.The microscopic damage evolution law of loaded sandstone under the freeze-thaw cycle is analyzed by conducting Nuclear Magnetic Resonance(NMR)and uniaxial compression acoustic emission(AE)experiments.The experimental results have shown that:(1)Freeze-thaw cycling increases sandstone's internal pores,enlarges the pore size,and modifies the original pore distribution.(2)The damage due to freeze-thaw cycling is positively correlated with the initial damage to the rock,and the damage on the rock surface is more severe than inside the rock sample.(3)Freeze-thaw cycling negatively impacts the mechanical properties of sandstone,and the elastic deformation stage of sandstone gradually decreases as the number of freeze-thaw cycles increases and gradually transitions from brittle failure to ductile failure.(4)The characteristic parameters of AE ringing count and accumulated energy can reveal the severity of freeze-thaw damage and the dynamic evolution process,and the damage development rate exhibits abrupt changes at critical moments.After five freeze-thaw cycles,the damage development rate rises suddenly,as manifested by a sharp increase in the frequency and energy of AE events.High-energy AE events frequently occur during the rapid expansion period of damage,which can be adopted as an essential reference for damage propagation and aggravation.
基金supported by National Natural Science Foundation of China(Nos.51977202,U1830135,51807189)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20170004).
文摘The surface trap parameter can significantly affect the development of surface flashover in vacuum,but the effective mode and mechanism are not very clear yet.The trap parameters of three polymeric materials were tested and calculated by means of isothermal surface potential decay.The flashover experiment was developed under different applied voltages.The results show a positive correlation between the withstand voltage and the deep trap,i.e.,the deeper trap energy level is,the higher flashover voltage is.The dynamics process of charge trapping and detrapping was analyzed based on the charge transport model in dielectrics with a single trap level and two discrete trap levels.The time of charge trapping was compared with that of the discharge development.The results show that the charge trapping time is longer than the flashover development time.The way to influence flashover for a trap is not to decrease the secondary electrons in single discharge development,but to change the electric field distribution on the dielectric surface by charge capture.
基金financial support from the National Natural Science Foundation of China under Grant No.50978007
文摘Weak structural surface is one of the key factors controlling the stability of slopes. The stability of rock slopes is in general concerned with set of discontinuities. However, in soft rocks, failure can occur along surfaces approaching to a circular failure surface. To better understand the position of potential sliding surface, a new method called simplex-finite stochastic tracking method is proposed. This method basically divides sliding surface into two parts： one is described by smooth curve obtained by random searching, the other one is po｜yline formed by the weak structural surface. Single or multiple sliding surfaces can be considered, and consequently several types of combined sliding surfaces can be simu- lated. The paper will adopt the arc-polyline to simulate potential sliding surface and analyze the searching process of sliding surface. Accordingly, software for slope stability analysis using this method was developed and applied in real cases. The results show that, using simplex-finite stochastic tracking method, it is possible to locate the position of a potential sliding surface in the slope.
文摘In the multi-wave and multi-component seismic exploration,shear-wave will be split into fast wave and slow wave,when it propagates in anisotropic media. Then the authors can predict polarization direction and density of crack and detect the development status of cracks underground according to shear-wave splitting phenomenon. The technology plays an important role and shows great potential in crack reservoir detection. In this study,the improved particle swarm optimization algorithm based on shrinkage factor is combined with the Pearson correlation coefficient method to obtain the fracture azimuth angle and density. The experimental results show that the modified method can improve the convergence rate,accuracy,anti-noise performance and computational efficiency.
基金This work was supported by the National Natural Science Foundation of China[grant number 41101410]the Comprehensive Transportation Applications of High-resolution Remote Sensing program[grant number 07-Y30B10-9001-14/16]+1 种基金the Key Laboratory of Surveying Mapping and Geoinformation in Geographical Condition Monitoring[grant number 2014NGCM]the Science and Technology Plan of Sichuan Bureau of Surveying,Mapping and Geoinformation,China[grant number J2014ZC02].
文摘Inclusion of textures in image classification has been shown beneficial.This paper studies an efficient use of semivariogram features for object-based high-resolution image classification.First,an input image is divided into segments,for each of which a semivariogram is then calculated.Second,candidate features are extracted as a number of key locations of the semivariogram functions.Then we use an improved Relief algorithm and the principal component analysis to select independent and significant features.Then the selected prominent semivariogram features and the conventional spectral features are combined to constitute a feature vector for a support vector machine classifier.The effect of such selected semivariogram features is compared with those of the gray-level co-occurrence matrix(GLCM)features and window-based semivariogram texture features(STFs).Tests with aerial and satellite images show that such selected semivariogram features are of a more beneficial supplement to spectral features.The described method in this paper yields a higher classification accuracy than the combination of spectral and GLCM features or STFs.
文摘This study takes a fractured rock mass in the Datengxia Hydropower Station,China as an example to analyze the size effects and determine the representative elementary sizes.A novel method considering geometric parameter distributions is proposed in this work.The proposed method can quickly and simply determine the size effects and representative elementary sizes.Specifically,geometric parameter distributions,including fracture frequency,size and orientation,are generated on the basis of the Bernoulli trial and Monte Carlo simulation.The distributions are assessed using the coefficient of variation(CV),and the acceptable variations for CV(5%,10%and 20%)are used to determine representative elementary sizes.Generally,the representative element of rock masses is the representative elementary volume(REV).The present study extends the representative element to other dimensions,i.e.representative elementary length(REL)and representative elementary area(REA)for one and two dimensions,respectively.REL and REA are useful in studying the size effects of one-(1D)and twodimensional(2D)characteristics of rock masses.The relationships among multi-dimensional representative elementary sizes are established.The representative elementary sizes reduce with the increase in the dimensions,and REA and REV can be deduced by REL.Therefore,the proposed method can quickly and simply determine REL and further estimate REA and REV,which considerably improves the efficiency of rock mass analysis.
基金supported by the Director Foundation of Institute of Seismology, CEA (Grant Number: IS201326127)the National Natural Science Foundation of China (Grant Numbers: 41404016, 41474097)
文摘South and north-dipping nodal planes from the U.S. Geological Survey moment tensor solution were used to invert global teleseismic body waves to reveal the source rupture process of the December 8, 2016, Mw6.0 Hutubi earthquake. The results show that a compact pattern is the main feature of this event for only one main slip zone located at the hypocenter for both models, The slip distributions are dominated by a nearly pure-thrust fault, and there is no apparent surface rupture. The inversion revealed that the slip zone extends 10 km along strike and 12 km along dip. The released total seismic moment was about 9.0 -1017 Nm, corresponding to a magnitude of Mw6.0. It is difficult to solve for a best-fit rupture plane due to the sample slip pattern without obvious rupture directivity. This makes the far- field teleseismic data not sensitive enough to determine the fault geometric parameters. The source model of the reverse north-dipping plane fits well with the observed waveforms, and the results of the aftershock relocation outline a trend of north-dipping profiles, indicating the possibility of a reverse event. The inverted normal fault beneath the Qigu fold, interpreted by geological and seismic studies, may be the seismogenic fault for this reverse event.
基金supported by the National Hi-Tech Research and Development Program (863) of China (No. 2011AA060902)
文摘Alkaline treatment with steel slag and NaOH addition were investigated under different pH conditions for the fermentation of waste activated sludge. Better performance was achieved in steel slag addition scenarios for both sludge hydrolysis and acidification. More solubilization of organic matters and much production of higher VFA （volatile fatty acid） in a shorter time can be achieved at pH 10 when adjusted by steel slag. Higher enzyme activities were also observed in steel slag addition scenarios under the same pH conditions. Phosphorus concentration in the supematant increased with fermentation time and pH in NaOH addition scenarios, while in contrast most phosphorus was released and captured by steel slag simultaneously in steel slag addition scenarios. These results suggest that steel slag can be used as a substitute for NaOH in sludge alkaline treatment.
基金supported by the National Natural Science Foundation of China(42174026)the National Key Research and Development Program of China(2021YFE011004)。
文摘The permafrost development in the Qinghai-Tibet Engineering Corridor(QTEC)is affected by natural environment changes and human engineering activities.Human engineering activities may damage the permafrost growing environment,which in turn impact these engineering activities.Thus high spatial-temporal resolution monitoring over the QTEC in the permafrost region is very necessary.This paper presents a method for monitoring the frozen soil area using the intermittent coherencebased small baseline subset(ICSBAS).The method can improve the point density of the results and enhance the interpretability of deformation results by identifying the discontinuous coherent points according to the coherent value of time series.Using the periodic function that models the seasonal variation of permafrost,we separate the long wavelength atmospheric delay and establish an estimation model for the frozen soil deformation.Doing this can raise the monitoring accuracy and improve the understanding of the surface deformation of the frozen soil.In this study,we process 21 PALSAR data acquired by the Alos satellite with the proposed ICSBAS technique.The results show that the frozen soil far from the QTR in the study area experiences frost heave and thaw settlement(4.7 cm to8.4 cm)alternatively,while the maximum settlement along the QTR reaches 12 cm.The interferomatric syntnetic aperture radar(InSAR)-derived results are validated using the ground leveling data nearby the Beiluhe basin.The validation results show the InSAR results have good consistency with the leveling data in displacement rates as well as time series.We also find that the deformation in the permafrost area is correlated with temperature,human activities and topography.Based on the interfering degree of human engineering activities on the permafrost environment,we divide the QTEC along the Qinghai-Tibet Railway into engineering damage zone,transition zone and natural permafrost.
文摘Spiking deconvolution is a standard Wiener Levinson algorithm. The autocorrelation of the design time gate is computed and there is a specified taper on the design gate before the autoeorrelation is done. The standard equations are set up, prewhitening is added to the zero lag value of the autocorrelation and the matrix is inverted to derive the spiking operator. In this study, the authors describe a technique for performing spiking deconvolution on prestack time migration （PSTM） data, to test the effect of operator length and percent prewhitening in spiking deconvolution and apply spiking deconvolution trace by trace, with operator lengths 15ms, 10 ms and 5 ms when percent prewhitening 0% , 40ms and 60ms for percent prewhitening 1%. The results show when prewhitening is 0% the shorter operator gives better results, but when value of prewhitening is bigger than 0% it is better to use longer operator lengths.
