量化剩余电寿命是断路器寿命评价的关键。在研究断路器开断过程和电弧能量累积加权法的基础上,研究断路器剩余电寿命预警系统拓扑结构,深入讨论了采集单元的硬件原理和工作逻辑、合并单元通信方式、上位机软件功能和系统运行流程。研发...量化剩余电寿命是断路器寿命评价的关键。在研究断路器开断过程和电弧能量累积加权法的基础上,研究断路器剩余电寿命预警系统拓扑结构,深入讨论了采集单元的硬件原理和工作逻辑、合并单元通信方式、上位机软件功能和系统运行流程。研发了投切电抗器/电容器用断路器剩余电寿命预警系统,并部署在某110 k V变电站,不仅能记录断路器开断电流的波形,还能根据剩余电寿命阈值发出告警提示,预测剩余电寿命发展趋势,为断路器管理维护提供辅助决策。展开更多
A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the batt...A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.展开更多
Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. batte...Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. battery, the state of charge indicator for lead-acid battery was developed by means of an algorithm based on combination of ampere-hour, Peukert's equation and open-voltage method with the compensation of temperature,aging,self- discharging,etc..Results The BMS based on this method can attain an accurate surplus capa- city whose error is less than 5% in static experiments.It is proved by experiments that the BMS is reliable and can give the driver an accurate surplus capacity,precisely monitor the individual battery modules as the same time,even detect and warn the problems early,and so on. Conclusion A BMS can make the energy of the storage batteries used efficiently, develop the batteries cycle life,and increase the driving distance of EVs.展开更多
Oxygen vacancy (Ov) has significant influence on physical and chemical properties of TiO2 systems, especially on surface catalytic processes. In this work, we investigate the effects of Ov on the adsorption of forma...Oxygen vacancy (Ov) has significant influence on physical and chemical properties of TiO2 systems, especially on surface catalytic processes. In this work, we investigate the effects of Ov on the adsorption of formaldehyde (HCHO) on TiO2(110) surfaces through first- principles calculations. With the existence of Ov, we find the spatial distribution of surface excess charge can change the relative stability of various adsorption configurations. In this case, the bidentate adsorption at five-coordinated Ti (Tisc) can be less stable than the monodentate adsorption. And HCHO adsorbed in Ov becomes the most stable structure. These results are in good agreement with experimental observations, which reconcile the long-standing deviation between the theoretical prediction and experimental results. This work brings insights into how the excess charge affects the molecule adsorption on metal oxide surface.展开更多
Based on the three-dimensional ECOM model,the tide,tide-induced residual current,wind-driven and density currents in the Beibu (Tonkin) Gulf and Qiongzhou Strait are diagnostically computed in fine grid.The tides and ...Based on the three-dimensional ECOM model,the tide,tide-induced residual current,wind-driven and density currents in the Beibu (Tonkin) Gulf and Qiongzhou Strait are diagnostically computed in fine grid.The tides and tidal currents in the Beibu Gulf and Qiongzhou Strait are well reproduced.The model results show that the semidiurnal tidal wave propagates eastward from the Beibu Gulf through Qiongzhou Strait,while diurnal tidal waves enter the strait from both the eastern and western sides and interact on the southeast coast of the strait.The formation processes of the residual currents in Qiongzhou Strait in summer (August) and winter (January) are mainly discussed.It is shown that the total residual currents (coupling effect of wind,tide and density) in the strait are westward in both summer and winter.The water volume transported from the east to west into the Beibu Gulf is 0.026 Sv in summer and 0.116 Sv in winter.Numerical experiments indicate that the dominant factor affecting the residual currents in the strait is not the wind stress but the tidal rectification.The westward tide-induced residual current,driven by the tidal rectification,is rather strong in the strait with water volume transport of 0.063 Sv.The wind in summer only reduces the westward tide-induced residual current to a certain extent,and the wind in winter approximately doubles the westward tide-induced residual current through the strait.The density current contributes little to the total residual current in both summer and winter.展开更多
Although high resolution can be provided by electrical logging, the measured electrical log range is narrow and is limited to near the well. Borehole-surface electric potential measurements are able to detect a wide e...Although high resolution can be provided by electrical logging, the measured electrical log range is narrow and is limited to near the well. Borehole-surface electric potential measurements are able to detect a wide enough range but its resolution is limited, particularly for reservoirs with complex oil and water distribution or complicated structure. In this study, we attempt to accurately locate the 3-D reservoir water and oil distribution by combining borehole-surface and crosswell electric potentials. First, the distributions of oil and water in both vertical and horizontal directions are detected by the borehole-surface and erosswell electric potential methods, respectively, and then the measured crosswell potential result is used to calibrate the measured borehole-surface electric potential data to improve vertical resolution so that the residual oil distribution is determined in a lower half-space with three dimensions. The evaluation of residual oil distribution is obtained by investigation of differences between the simulation results of the reservoir with and without water flooding. The finite difference numerical simulation results prove that the spatial residual oil distribution can be effectively determined by combining the crosswell and borehole-surface electric potentials.展开更多
Bottom currents at about 1000m depth in and around a submarine valley on the continental slope of the northern South China Sea were studied by a 14-month long experiment from July 2013 to September 2014. The observati...Bottom currents at about 1000m depth in and around a submarine valley on the continental slope of the northern South China Sea were studied by a 14-month long experiment from July 2013 to September 2014. The observations reveal that bottom currents are strongly influenced by the topography, being along valley axis or isobaths. Power density spectrum analysis shows that all the currents have significant peaks at diurnal and semi-diurnal frequencies. Diurnal energy is dominant at the open slope site, which is consistent with many previous studies. However, at the site inside the valley the semi-diurnal energy dominates, although the distance between the two sites of observation is quite small (11 kin) compared to a typical horizontal first-mode internal tide wavelength (200 km). We found this phenomenon is caused by the focusing of internal waves of certain frequencies in the valley. The inertial peak is found only at the open slope site in the first deployment but missing at the inside valley site and the rest of the de- ployments. Monthly averaged residual currents reveal that the near-bottom currents on the slope flow southwestward throughout the year except in August and September, 2013, from which we speculate that this is a result of the interaction between a mesoscale eddy and the canyon/sag topography. Currents inside the valley within about 10mab basically flow along slope and in the layers above the 10mab the currents are northwestward, that is, from the deep ocean to the shelf. The monthly mean current vectors manifest an Ek- man layer-like vertical structure at both sites, which rotate counter-clockwise looking from above.展开更多
Data taken in the two large-scale ocean investigations in China in winter 1959 and 1982 are used to analyze the residual current off the Changjiang (Yangtze) River mouth in this paper. The current in wintertime off th...Data taken in the two large-scale ocean investigations in China in winter 1959 and 1982 are used to analyze the residual current off the Changjiang (Yangtze) River mouth in this paper. The current in wintertime off the river mouth consist of the Changjiang runoff, wind-driven current, coastal current, density-driven current and Taiwan Warm Current (TWC). The TWC occurs in wintertime off the mouth. The surface TWC reaches only to the east side of Dinghai, then turns southeastward. The bottom TWC can flow to the area off the Changjiang mouth along west slop of the submerged river valley (SRV) and to the area off the Subei coast. The simulated currents by 3D model are basically consistent with the observed currents, although the model was run with climatological forces and the observations was done in episodic time manner.展开更多
Data taken in two large scale ocean observations in China in summer 1959 and 1982 were used to analyze the residual current off the Changjiang (Yangtze) River mouth. The currents at surface off the mouth in July 1959 ...Data taken in two large scale ocean observations in China in summer 1959 and 1982 were used to analyze the residual current off the Changjiang (Yangtze) River mouth. The currents at surface off the mouth in July 1959 and 1982 flow northeastward and eastward due to the river discharge, the current speed was larger in1982 than in 1959. All the bottom currents flow landward due to baroclinic effect. The surface current was controlled by the river runoff and the Taiwan Warm Current (TWC). A return current at surface off the mouth was observed in September 1959. In general, the bottom currents were controlled by the TWC in most study area in addition to the runoff near the mouth. Although driven by 3-D model with the monthly averaged forces (river discharge, wind stress, baroclinic effect, open boundary water volume flux and tidal mixing) in August, the simulated circulations were basically consistent with the observed ones with episodic time manner.展开更多
Predicting the life of Ni-Cd battery for electric multiple units(EMU)can not only improve the safety and reliability of battery,but also reduce the operating costs of EMU.For this reason,a life prediction method based...Predicting the life of Ni-Cd battery for electric multiple units(EMU)can not only improve the safety and reliability of battery,but also reduce the operating costs of EMU.For this reason,a life prediction method based on linear Wiener process is proposed,which is suitable for both monotonic and non-monotonic degraded systems with accurate results.Firstly,a unary linear Wiener degradation model is established,and the parameters of the model are estimated by using the expectation-maximization algorithm(EM).With the established model,the remaining useful life(RUL)of Ni Cd battery and its distribution are obtained.Then based on the unary Wiener process degradation model,the correlation between capacity and energy is analyzed through Copula function to build a binary linear Wiener degradation model,where its parameters are estimated using Markov Chain Monte Carlo(MCMC)method.Finally,according to the binary Wiener process model,the battery RUL and its distribution are acquired.The experimental results show that the binary linear Wiener degradation model based on capacity and energy possesses higher accuracy than the unary linear wiener process degradation model.展开更多
The way of neutral point to earth via full compensation arc suppression coil can solve the problem of residual current compensation in coal mine power network effectively. Based on the analysis on the grounding curren...The way of neutral point to earth via full compensation arc suppression coil can solve the problem of residual current compensation in coal mine power network effectively. Based on the analysis on the grounding current detection results of Xieqiao coal mine, the conclusion that harmonic component of grounding current is dominated by higher harmonics with complex harmonic sources in coal mine power network system was obtained. The influences of harmonic source type and fault point position on harmonic voltage and harmonic current were analyzed theoretically. The influences of earthed fault feeder detection result and the estimation errors of parameters to earth on residual current compensation were analyzed. A new thought of residual current prediction and the selections of model method and control method were proposed on this basis. The simulation results prove that harmonic amplitudes of zero sequence voltage and zero sequence current are determined by harmonic source type as well as fault point position in coal mine power network, and also prove that zero sequence voltage detection can avoid the unstable problem of coal mine power network system caused by undercompensation of capacitive current. Finally, the experimental device of full compensation arc suppression coil is introduced.展开更多
Ten years (from 2005 to 2014) of satellite sea surface temperature (SST) data from the Advanced Very High Resolution Radiometer (AVHRR) are analyzed to reveal the monthly changes in surface cold patches (SCPs)...Ten years (from 2005 to 2014) of satellite sea surface temperature (SST) data from the Advanced Very High Resolution Radiometer (AVHRR) are analyzed to reveal the monthly changes in surface cold patches (SCPs) in the main areas of the Northern Yellow Sea (NYS). The Canny edge detection algorithm is used to identify the edges of the patches. The monthly changes are de- scribed in terms of location, temperature and area. The inter-annual variations, including changes in the location and area of the SCPs from 2010 to 2014, are briefly discussed. The formation mechanisms of the SCPs in different periods are systematically analyzed using both in situ data and numerical simulation. The results show that from May to October, the location and area of the SCPs re- main stable, with a north-south orientation. The SCPs altogether cover about I° of longitude (124°E-125°E) in width and 2° of lati- tude (37.5°N-39.5°N) in length. In November, the SCP separates from the Jangsan Cape and forms a closed, isolated, and approxi- mately circular cold patch in the central NYS. From May to October, the upweUing that leads to the formation of the SCP is mainly triggered by the headland residual current, wind field, climbing movement of the current and secondary circulation at the tide front. In November, cyclonic circulation in the NYS is primarily responsible for generating the upwelling that leads to the formation of the closed and isolated SCE展开更多
文摘量化剩余电寿命是断路器寿命评价的关键。在研究断路器开断过程和电弧能量累积加权法的基础上,研究断路器剩余电寿命预警系统拓扑结构,深入讨论了采集单元的硬件原理和工作逻辑、合并单元通信方式、上位机软件功能和系统运行流程。研发了投切电抗器/电容器用断路器剩余电寿命预警系统,并部署在某110 k V变电站,不仅能记录断路器开断电流的波形,还能根据剩余电寿命阈值发出告警提示,预测剩余电寿命发展趋势,为断路器管理维护提供辅助决策。
文摘A kind of management system for electric vehicle (EV) battery series was developed. The system can predict residual capacity for EV battery series and mileages. The system can determine if it is necessary for the battery series to be charged. The system can determine which battery is necessary to be updated for the reason of damage or aging. The system can display the total voltage of battery series, extreme voltage and temperature of every battery in the series. The system can display the accumulative discharge for every battery in the series. The system can alarm when both total or extreme voltage is at low level, or temperature of a battery in the series is at high level. The system provided with a microprocessor as key part can collect and record signal of charging and discharging current, total voltage, extreme voltage and temperature for every battery. The mathematical model of residual capacity for EV lead acid batteries was discussed in details. The system operates well in the laboratory and meets the requirement.
文摘Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. battery, the state of charge indicator for lead-acid battery was developed by means of an algorithm based on combination of ampere-hour, Peukert's equation and open-voltage method with the compensation of temperature,aging,self- discharging,etc..Results The BMS based on this method can attain an accurate surplus capa- city whose error is less than 5% in static experiments.It is proved by experiments that the BMS is reliable and can give the driver an accurate surplus capacity,precisely monitor the individual battery modules as the same time,even detect and warn the problems early,and so on. Conclusion A BMS can make the energy of the storage batteries used efficiently, develop the batteries cycle life,and increase the driving distance of EVs.
文摘Oxygen vacancy (Ov) has significant influence on physical and chemical properties of TiO2 systems, especially on surface catalytic processes. In this work, we investigate the effects of Ov on the adsorption of formaldehyde (HCHO) on TiO2(110) surfaces through first- principles calculations. With the existence of Ov, we find the spatial distribution of surface excess charge can change the relative stability of various adsorption configurations. In this case, the bidentate adsorption at five-coordinated Ti (Tisc) can be less stable than the monodentate adsorption. And HCHO adsorbed in Ov becomes the most stable structure. These results are in good agreement with experimental observations, which reconcile the long-standing deviation between the theoretical prediction and experimental results. This work brings insights into how the excess charge affects the molecule adsorption on metal oxide surface.
基金Supported by the National Basic Research Program (973 Program) (No.2007CB411807)the Open Research Program of the CAS Key Laboratory of Tropical Marine Environmental Dynamics (No.LED0404)+1 种基金the Key Project of Chinese Ministry of Education (No.108159)the National Key Technologies R&D Program (No.2007BAC03A06),China
文摘Based on the three-dimensional ECOM model,the tide,tide-induced residual current,wind-driven and density currents in the Beibu (Tonkin) Gulf and Qiongzhou Strait are diagnostically computed in fine grid.The tides and tidal currents in the Beibu Gulf and Qiongzhou Strait are well reproduced.The model results show that the semidiurnal tidal wave propagates eastward from the Beibu Gulf through Qiongzhou Strait,while diurnal tidal waves enter the strait from both the eastern and western sides and interact on the southeast coast of the strait.The formation processes of the residual currents in Qiongzhou Strait in summer (August) and winter (January) are mainly discussed.It is shown that the total residual currents (coupling effect of wind,tide and density) in the strait are westward in both summer and winter.The water volume transported from the east to west into the Beibu Gulf is 0.026 Sv in summer and 0.116 Sv in winter.Numerical experiments indicate that the dominant factor affecting the residual currents in the strait is not the wind stress but the tidal rectification.The westward tide-induced residual current,driven by the tidal rectification,is rather strong in the strait with water volume transport of 0.063 Sv.The wind in summer only reduces the westward tide-induced residual current to a certain extent,and the wind in winter approximately doubles the westward tide-induced residual current through the strait.The density current contributes little to the total residual current in both summer and winter.
文摘Although high resolution can be provided by electrical logging, the measured electrical log range is narrow and is limited to near the well. Borehole-surface electric potential measurements are able to detect a wide enough range but its resolution is limited, particularly for reservoirs with complex oil and water distribution or complicated structure. In this study, we attempt to accurately locate the 3-D reservoir water and oil distribution by combining borehole-surface and crosswell electric potentials. First, the distributions of oil and water in both vertical and horizontal directions are detected by the borehole-surface and erosswell electric potential methods, respectively, and then the measured crosswell potential result is used to calibrate the measured borehole-surface electric potential data to improve vertical resolution so that the residual oil distribution is determined in a lower half-space with three dimensions. The evaluation of residual oil distribution is obtained by investigation of differences between the simulation results of the reservoir with and without water flooding. The finite difference numerical simulation results prove that the spatial residual oil distribution can be effectively determined by combining the crosswell and borehole-surface electric potentials.
基金funded by China National Offshore Oil Corporation (CNOOC)sponsored by the National Natural Science Foundation of China (Nos.41406031 and 41376038)NSFC-Shandong Joint Fund for Marine Science Research Centers (No.U1406404)
文摘Bottom currents at about 1000m depth in and around a submarine valley on the continental slope of the northern South China Sea were studied by a 14-month long experiment from July 2013 to September 2014. The observations reveal that bottom currents are strongly influenced by the topography, being along valley axis or isobaths. Power density spectrum analysis shows that all the currents have significant peaks at diurnal and semi-diurnal frequencies. Diurnal energy is dominant at the open slope site, which is consistent with many previous studies. However, at the site inside the valley the semi-diurnal energy dominates, although the distance between the two sites of observation is quite small (11 kin) compared to a typical horizontal first-mode internal tide wavelength (200 km). We found this phenomenon is caused by the focusing of internal waves of certain frequencies in the valley. The inertial peak is found only at the open slope site in the first deployment but missing at the inside valley site and the rest of the de- ployments. Monthly averaged residual currents reveal that the near-bottom currents on the slope flow southwestward throughout the year except in August and September, 2013, from which we speculate that this is a result of the interaction between a mesoscale eddy and the canyon/sag topography. Currents inside the valley within about 10mab basically flow along slope and in the layers above the 10mab the currents are northwestward, that is, from the deep ocean to the shelf. The monthly mean current vectors manifest an Ek- man layer-like vertical structure at both sites, which rotate counter-clockwise looking from above.
文摘Data taken in the two large-scale ocean investigations in China in winter 1959 and 1982 are used to analyze the residual current off the Changjiang (Yangtze) River mouth in this paper. The current in wintertime off the river mouth consist of the Changjiang runoff, wind-driven current, coastal current, density-driven current and Taiwan Warm Current (TWC). The TWC occurs in wintertime off the mouth. The surface TWC reaches only to the east side of Dinghai, then turns southeastward. The bottom TWC can flow to the area off the Changjiang mouth along west slop of the submerged river valley (SRV) and to the area off the Subei coast. The simulated currents by 3D model are basically consistent with the observed currents, although the model was run with climatological forces and the observations was done in episodic time manner.
文摘Data taken in two large scale ocean observations in China in summer 1959 and 1982 were used to analyze the residual current off the Changjiang (Yangtze) River mouth. The currents at surface off the mouth in July 1959 and 1982 flow northeastward and eastward due to the river discharge, the current speed was larger in1982 than in 1959. All the bottom currents flow landward due to baroclinic effect. The surface current was controlled by the river runoff and the Taiwan Warm Current (TWC). A return current at surface off the mouth was observed in September 1959. In general, the bottom currents were controlled by the TWC in most study area in addition to the runoff near the mouth. Although driven by 3-D model with the monthly averaged forces (river discharge, wind stress, baroclinic effect, open boundary water volume flux and tidal mixing) in August, the simulated circulations were basically consistent with the observed ones with episodic time manner.
基金Project(2017 YFB 1200801-12)supported by the National Natural Science Foundation of China。
文摘Predicting the life of Ni-Cd battery for electric multiple units(EMU)can not only improve the safety and reliability of battery,but also reduce the operating costs of EMU.For this reason,a life prediction method based on linear Wiener process is proposed,which is suitable for both monotonic and non-monotonic degraded systems with accurate results.Firstly,a unary linear Wiener degradation model is established,and the parameters of the model are estimated by using the expectation-maximization algorithm(EM).With the established model,the remaining useful life(RUL)of Ni Cd battery and its distribution are obtained.Then based on the unary Wiener process degradation model,the correlation between capacity and energy is analyzed through Copula function to build a binary linear Wiener degradation model,where its parameters are estimated using Markov Chain Monte Carlo(MCMC)method.Finally,according to the binary Wiener process model,the battery RUL and its distribution are acquired.The experimental results show that the binary linear Wiener degradation model based on capacity and energy possesses higher accuracy than the unary linear wiener process degradation model.
基金The financial support from the National Natural Science Foundation of China (No. 51107143)
文摘The way of neutral point to earth via full compensation arc suppression coil can solve the problem of residual current compensation in coal mine power network effectively. Based on the analysis on the grounding current detection results of Xieqiao coal mine, the conclusion that harmonic component of grounding current is dominated by higher harmonics with complex harmonic sources in coal mine power network system was obtained. The influences of harmonic source type and fault point position on harmonic voltage and harmonic current were analyzed theoretically. The influences of earthed fault feeder detection result and the estimation errors of parameters to earth on residual current compensation were analyzed. A new thought of residual current prediction and the selections of model method and control method were proposed on this basis. The simulation results prove that harmonic amplitudes of zero sequence voltage and zero sequence current are determined by harmonic source type as well as fault point position in coal mine power network, and also prove that zero sequence voltage detection can avoid the unstable problem of coal mine power network system caused by undercompensation of capacitive current. Finally, the experimental device of full compensation arc suppression coil is introduced.
基金supported by the National Natural Science Foundation of China (No.41276041)the NSFC–Shandong Joint Fund for Marine Science Research Centers (No.U1406404)
文摘Ten years (from 2005 to 2014) of satellite sea surface temperature (SST) data from the Advanced Very High Resolution Radiometer (AVHRR) are analyzed to reveal the monthly changes in surface cold patches (SCPs) in the main areas of the Northern Yellow Sea (NYS). The Canny edge detection algorithm is used to identify the edges of the patches. The monthly changes are de- scribed in terms of location, temperature and area. The inter-annual variations, including changes in the location and area of the SCPs from 2010 to 2014, are briefly discussed. The formation mechanisms of the SCPs in different periods are systematically analyzed using both in situ data and numerical simulation. The results show that from May to October, the location and area of the SCPs re- main stable, with a north-south orientation. The SCPs altogether cover about I° of longitude (124°E-125°E) in width and 2° of lati- tude (37.5°N-39.5°N) in length. In November, the SCP separates from the Jangsan Cape and forms a closed, isolated, and approxi- mately circular cold patch in the central NYS. From May to October, the upweUing that leads to the formation of the SCP is mainly triggered by the headland residual current, wind field, climbing movement of the current and secondary circulation at the tide front. In November, cyclonic circulation in the NYS is primarily responsible for generating the upwelling that leads to the formation of the closed and isolated SCE