Spherical Ni（OH）2 particles were prepared by an aqueous solution precipitation route. The structure of spherical Ni（OH）2 was investigated by scanning electron microscopy and transmission electron microscopy and co...Spherical Ni（OH）2 particles were prepared by an aqueous solution precipitation route. The structure of spherical Ni（OH）2 was investigated by scanning electron microscopy and transmission electron microscopy and compared with that of traditional Ni（OH）2. The results show that the spherical nickel hydroxide consists of （Ni（OH）2） spheres with a reticulate structure of platelet-like, which is almost arranged radially and the crystalline grains intervene and connect with each other to form a three-dimensional net. The spherical Ni（OH）2 particle is full of pores, crannies between cleave planes. It is supposed that this structure is beneficial to the structural stability for the spherical particles during the charge/discharge processes and can improve the cycle life of the electrode; the pores and the crannies in spherical particles can shorten the proton diffusion distance and speed its velocity, which may result in that the local polarization is lowered. The electrochemical performances of the spherical Ni（OH）2 are improved by enhancing the conducting properties of the crystalline lattice due to its quick proton diffusion.展开更多
Ether-based electrolytes with relatively high stability are widely used in Li-O_(2) batteries (LOBs) with high energy density.However,they are still prone to be attacked by reactive oxygen species.Understanding the de...Ether-based electrolytes with relatively high stability are widely used in Li-O_(2) batteries (LOBs) with high energy density.However,they are still prone to be attacked by reactive oxygen species.Understanding the degradation chemistry of ether-based solvent induced by reactive oxygen species is significant importance toward selection of stable electrolytes for LOBs.Herein,we demonstrate that a great amount of H_(2) gas evolves on the Li anode during the long-term discharge process of LOBs,which is due to the electrolyte decomposition at the oxygen cathode.By coupling with in-situ and ex-situ characterization techniques,it is demonstrated that O_(2)^(-) induces the H-abstraction of tetraethylene glycol dimethyl ether(TEGDME) to produce a large amount of H_(2)O at cathode,and this H_(2)O migrates to Li anode and produce H_(2) gas.Based on the established experiments and spectra,a possible decomposition pathway of TEGDME caused by O_(2)^(-)at the discharge process is proposed.And moreover,three types of strategies are discussed to inhibit the decomposition of ether-based electrolytes,which should be highly important for the fundamental and technical advancement for LOBs.展开更多
Theoretical study on the electronic structures and related properties of 2,2,6,6-tetramethyl- l-piperidinyloxy （TEMPO） and its cationic lipid derivates in the charge/discharge processes has been carried out using th...Theoretical study on the electronic structures and related properties of 2,2,6,6-tetramethyl- l-piperidinyloxy （TEMPO） and its cationic lipid derivates in the charge/discharge processes has been carried out using the density functional theory （DFT） at the （U）B3LYP/6-31G（d,p） or 6-31＋G（d,p） level. The changes and regularities of geometric and electronic properties of these compounds in the charge/discharge processes were revealed in detail. The compu- tational results show that the substitute group plays a very important role in the electronic structures and related properties of TEMPOs during the charge/discharge processes. It is very interesting to find that after getting an electron, TEMPO is more stable in singlet state but the lipid is more stable in triplet state. For TEMPO, both the charge and the discharge processes greatly influence the electronic properties of N and O atoms of the radical part. For the cationic lipid, the discharge process mainly influences the pyridinium head and the charge process mainly influences the free radical head. Moreover, the solvent effect plays an important role in some bond lengths and the charge population of the free radical head. In addition, the UV-Vis absorption spectra simulated using TDDFT at the 6-31G（d,p） with the experimental ones. of TEMPO and the lipid were calculated and or 6-31＋G（d,p） level, in satisfying agreement展开更多
As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge proce...As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages： （1） Joule heating and heat exchange stage; （2） nucleated site formation; （3） plasma generation （initiation of the breakdown stage）; （4） avalanche growth and plasma expansion; （5） plasma contraction; （6） termination of the plasma discharge; and （7） heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.展开更多
Based on experimental data and theory,by means of simplified discharge durations in a small flume,the influence of discharge process on channel morphology and channel pattern was analyzed in this paper.It was conclude...Based on experimental data and theory,by means of simplified discharge durations in a small flume,the influence of discharge process on channel morphology and channel pattern was analyzed in this paper.It was concluded that on the same original channel,different discharge and channel conditions would end with different river morphology,including thalwegs and radius of bends.Different discharge process resulted in two kinds of change:tiny change in the process of"big-small-big"and distinct change in the process of"small-big-small".Flood discharge duration was verified to be the main cause in the discharge process.Proper discharge process will change the morphologies of river,even can led to channel pattern transformation.The influences based on the relationship between the flow and the channel itself,including slope and riverbed constitution.Although not be a main cause,original channel morphology may influence its final channel pattern.Neglecting the influence of channel itself will hamper the understanding of channel patterns.展开更多
In order to effectively recover low and medium grade heat energy,a novel combined cooling and heating storage system based on zeolite-water is proposed in this paper.The system coupled the zeolite-water adsorption pro...In order to effectively recover low and medium grade heat energy,a novel combined cooling and heating storage system based on zeolite-water is proposed in this paper.The system coupled the zeolite-water adsorption process with the water evaporation refrigeration process during discharging process to realize generating cold energy and heat energy simultaneously.A more accurate kinetic model of zeolite and water adsorption is developed,and the thermodynamic performance of discharging process of the system is numerically analyzed.The results show the system has the higher energy conversion coefficient of 1.49 and the higher energy density of 1216.6 kJ/kg-zeolite.The change laws of system performances,such as energy generated,energy conversion coefficient and energy density,with key parameters during discharging process are revealed.The study provides a way for efficient utilization of low and medium grade heat energy.展开更多
The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of r...The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of reformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis- charge and discharge process are comprehensively analyzed according to the experimental data.It was found that the channel would be widened as the river slope or discharge increased and grain s...展开更多
The standard deviation of the central Pacific sea surface temperature anomaly （SSTA） during the period from October to February shows that the central Pacific SSTA variation is primarily due to the occurrence of the...The standard deviation of the central Pacific sea surface temperature anomaly （SSTA） during the period from October to February shows that the central Pacific SSTA variation is primarily due to the occurrence of the Central Pacific E1 Nifio （CP-E1 Nifio） and has a connection with the subtropical air-sea interaction in the northeastern Pacific. After removing the influence of the Eastern Pacific E1 Nifio, an S-EOF analysis is conducted and the leading mode shows a clear seasonal SSTA evolving from the subtropical northeastern Pacific to the tropical central Pacific with a quasi-biennial period. The initial subtropical SSTA is generated by the wind speed decrease and surface heat flux increase due to a north Pacific anomalous cyclone. Such subtropical SSTA can further influence the establishment of the SSTA in the tropical central Pacific via the wind-evaporation-SST （WES） feedback. After established, the central equatorial Pacific SSTA can be strengthened by the zonal advective feedback and thermocline feedback, and develop into CP-E1 Nifio. However, as the thermocline feedback increases the SSTA cooling after the mature phase, the heat flux loss and the reversed zonal advective feedback can cause the phase transition of CP-EI Nifio. Along with the wind stress variability, the recharge （discharge） process occurs in the central （eastern） equatorial Pacific and such a process causes the phase consistency between the thermocline depth and SST anomalies, which presents a contrast to the original recharge/discharge theory.展开更多
TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axio...TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axiovert 25 CA optical microscope with computer analyzing software （LEC）, GDA-2 glow discharge spectroscopy （GDS）, X-ray diffraction （XRD） and galvanochemical method. The results showed that the thickness of TiN/Ti multi-permeating alloying layer was about 10μm, the content of Ti on the surface was up to 63.48 wt% and the content of N was up to 12.46 wt%. The atom Ti and N concentrations changed gradually across the depth of the alloying layer and the preferred orientation of TiN/Ti alloying layer was crystal surface （200）. The multi-permeating alloying layer and substrate were combined through metallurgy. The surface appearances of the multi-permeating alloying layer were uniform and of a compact cellular structure. The hardness of the surface was about 1600-3000 HV0.1. The corrosion resistance of the permeating TiN/Ti alloying layer in 0.5 mol/L H2SO4 solution was greatly increased and the corrosion rate was only 0.3082 g/m^2. h.展开更多
In this study,a code,named Peking University Helicon Discharge(PHD),which can simulate helicon discharge processes under both a background magnetic field greater than 500 G and a pressure less than 1 Pa,is developed.I...In this study,a code,named Peking University Helicon Discharge(PHD),which can simulate helicon discharge processes under both a background magnetic field greater than 500 G and a pressure less than 1 Pa,is developed.In the code,two fluid equations are used.The PHD simulations led to two important findings:(1)the temporal evolution of plasma density with the background magnetic field exhibits a second rapid increase(termed as the second density jump),similar to the transition of modes in helicon plasmas;(2)in the presence of a magnetic field,the peak positions of electron power absorption appeared near the central axis,unlike in the case of no magnetic field.These results may lead to an enhanced understanding of the discharge mechanism.展开更多
Compressed air energy storage(CAES)is considered as one of the most promising large scale energy storage technologies for the electrical grid with high penetration of renewable energy.CAES systems are required to oper...Compressed air energy storage(CAES)is considered as one of the most promising large scale energy storage technologies for the electrical grid with high penetration of renewable energy.CAES systems are required to operate under complex conditions because of the pressure change in the air storage chamber and input/output power changes considering the fluctuated renewable generation and the mismatch between energy supply and demand.A dynamic operation configuration was proposed to satisfy the adjustment of off-design conditions of CAES systems and frequency management auxiliary service market.To regulate the inlet pressure of turbines and meet the output power demand for better performance,a thermodynamic model of a CAES discharging system with thermal storage and the pressure control unit(SER)was established.The control strategy of setting adjustment width instead of single instruction curve is proposed.Then,the dynamic operation parameters including pressure,mass flow rate,and exergy change during discharging processes were investigated.The superiority of the control accuracy and efficiency was demonstrated over single throttle valve through valve characterization studies.The SER system improves control accuracy by decoupling pressure and flow rate changes in dynamic operation,solving the problem of difficult control and low accuracy of traditional throttle valves.The expansion tank in SER serves as a pressure buffer and heat exchanger with the environment,reducing energy loss during fluid flow.Furthermore,the effect of the expansion tank volume of switch expansion reduction in exergy destruction were assessed.For a 10 MW/60MWh system with dynamic load to meet the requirements of the unit to participate in the frequency modulation auxiliary service market,the optimal added expansion tank volume is about 70m3.The optimization method of control strategy of SER system is also explored.The proposed optimized SER system of volume and control strategy can smoothly regulate the inlet pressure of the expander.When the adjustment width is 3bar,the frequency is 50%decreased,meanwhile,the on–off action time is more evenness,which ensures the stable and efficient operation of the CAES system and improves the comprehensive performance of the system.展开更多
Water pollution caused by dye is a serious challenge.Herein,we use a novel discharge process to functionalize carbon nanotube(CNT)by COOH groups to form CNT30 for removing methyl red(MR)from water.By pristine CNT,75%M...Water pollution caused by dye is a serious challenge.Herein,we use a novel discharge process to functionalize carbon nanotube(CNT)by COOH groups to form CNT30 for removing methyl red(MR)from water.By pristine CNT,75%MR is removed in 60 min,with an adsorption capacity of 68.44 mg g-1.By CNT30,85%MR is fast removed in only 5 min,and the removal efficiency reaches to 95%after 30 min,with an adsorption capacity of80.33 mg g-1.Thus,a higher MR removal efficiency is achieved in a much shorter time on CNT30.Moreover,CNT30 has an outstanding reusability,with the MR removal efficiency decreasing by only 7%after ten cycles.The COOH groups on CNT30 improve the hydrophilicity of CNT30,thus promoting the interaction of MR in water with CNT30.The hydrogen bonding and electrostatic interaction of MR with the COOH groups on CNT30 could be the force to drive MR adsorption on CNT30.The higher COOH content could be the origin for the better performance of CNT30 in removing dye from water.The discharge process developed herein is operated in O2,without using harmful substances,and the COOH content on CNT can be efficiently tuned by simply changing discharge time.This is different from the chemical modification widely used to functionalize CNT by strong oxidants,e.g.,HNO_(3).The present work is of great significance to realize green construction of materials for more efficiently removing dye from water.展开更多
基金Project(50134020) supported by the National Natural Science Foundation of China
文摘Spherical Ni（OH）2 particles were prepared by an aqueous solution precipitation route. The structure of spherical Ni（OH）2 was investigated by scanning electron microscopy and transmission electron microscopy and compared with that of traditional Ni（OH）2. The results show that the spherical nickel hydroxide consists of （Ni（OH）2） spheres with a reticulate structure of platelet-like, which is almost arranged radially and the crystalline grains intervene and connect with each other to form a three-dimensional net. The spherical Ni（OH）2 particle is full of pores, crannies between cleave planes. It is supposed that this structure is beneficial to the structural stability for the spherical particles during the charge/discharge processes and can improve the cycle life of the electrode; the pores and the crannies in spherical particles can shorten the proton diffusion distance and speed its velocity, which may result in that the local polarization is lowered. The electrochemical performances of the spherical Ni（OH）2 are improved by enhancing the conducting properties of the crystalline lattice due to its quick proton diffusion.
基金the National Natural Science Foundation of China (21773055, U1604122, 22005085)。
文摘Ether-based electrolytes with relatively high stability are widely used in Li-O_(2) batteries (LOBs) with high energy density.However,they are still prone to be attacked by reactive oxygen species.Understanding the degradation chemistry of ether-based solvent induced by reactive oxygen species is significant importance toward selection of stable electrolytes for LOBs.Herein,we demonstrate that a great amount of H_(2) gas evolves on the Li anode during the long-term discharge process of LOBs,which is due to the electrolyte decomposition at the oxygen cathode.By coupling with in-situ and ex-situ characterization techniques,it is demonstrated that O_(2)^(-) induces the H-abstraction of tetraethylene glycol dimethyl ether(TEGDME) to produce a large amount of H_(2)O at cathode,and this H_(2)O migrates to Li anode and produce H_(2) gas.Based on the established experiments and spectra,a possible decomposition pathway of TEGDME caused by O_(2)^(-)at the discharge process is proposed.And moreover,three types of strategies are discussed to inhibit the decomposition of ether-based electrolytes,which should be highly important for the fundamental and technical advancement for LOBs.
文摘Theoretical study on the electronic structures and related properties of 2,2,6,6-tetramethyl- l-piperidinyloxy （TEMPO） and its cationic lipid derivates in the charge/discharge processes has been carried out using the density functional theory （DFT） at the （U）B3LYP/6-31G（d,p） or 6-31＋G（d,p） level. The changes and regularities of geometric and electronic properties of these compounds in the charge/discharge processes were revealed in detail. The compu- tational results show that the substitute group plays a very important role in the electronic structures and related properties of TEMPOs during the charge/discharge processes. It is very interesting to find that after getting an electron, TEMPO is more stable in singlet state but the lipid is more stable in triplet state. For TEMPO, both the charge and the discharge processes greatly influence the electronic properties of N and O atoms of the radical part. For the cationic lipid, the discharge process mainly influences the pyridinium head and the charge process mainly influences the free radical head. Moreover, the solvent effect plays an important role in some bond lengths and the charge population of the free radical head. In addition, the UV-Vis absorption spectra simulated using TDDFT at the 6-31G（d,p） with the experimental ones. of TEMPO and the lipid were calculated and or 6-31＋G（d,p） level, in satisfying agreement
基金supported by National Natural Science Foundation of China(Nos.11205202,21203204 and 11175214)Natural Science Foundation of Anhui Province,China (No.1308085QA09)
文摘As one of the most important steps in wastewater treatment, limited study on plasma discharge process is a key challenge in the development of plasma applications. In this study, we focus on the plasma discharge process of a pulsed diaphragm discharge system. According to the analysis, the pulsed diaphragm discharge proceeds in seven stages： （1） Joule heating and heat exchange stage; （2） nucleated site formation; （3） plasma generation （initiation of the breakdown stage）; （4） avalanche growth and plasma expansion; （5） plasma contraction; （6） termination of the plasma discharge; and （7） heat exchange stage. From this analysis, a critical voltage criterion for breakdown is obtained. We anticipate this finding will provide guidance for a better application of plasma discharges, especially diaphragm plasma discharges.
基金Foundation item:Under the auspices of the Major State Basic Research Development Program of China(973 Program)(No.2003 CB415205)the National Natural Science Foundation of China(No.50479036)
文摘Based on experimental data and theory,by means of simplified discharge durations in a small flume,the influence of discharge process on channel morphology and channel pattern was analyzed in this paper.It was concluded that on the same original channel,different discharge and channel conditions would end with different river morphology,including thalwegs and radius of bends.Different discharge process resulted in two kinds of change:tiny change in the process of"big-small-big"and distinct change in the process of"small-big-small".Flood discharge duration was verified to be the main cause in the discharge process.Proper discharge process will change the morphologies of river,even can led to channel pattern transformation.The influences based on the relationship between the flow and the channel itself,including slope and riverbed constitution.Although not be a main cause,original channel morphology may influence its final channel pattern.Neglecting the influence of channel itself will hamper the understanding of channel patterns.
基金This study is financially supported by National Key R&D Plan(Grant No.2017YFB0903605)the National Science Fund for Distinguished Young Scholars(Grant No.51925604)+2 种基金International Partnership Program,Bureau of International Cooperation of Chinese Academy of Sciences(Grant No.182211KYSB20170029)Transformational Technologies for Clean Energy and Demonstration,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21070302)Beijing Key Laboratory of Distributed Combined Cooling Heating and Power System.
文摘In order to effectively recover low and medium grade heat energy,a novel combined cooling and heating storage system based on zeolite-water is proposed in this paper.The system coupled the zeolite-water adsorption process with the water evaporation refrigeration process during discharging process to realize generating cold energy and heat energy simultaneously.A more accurate kinetic model of zeolite and water adsorption is developed,and the thermodynamic performance of discharging process of the system is numerically analyzed.The results show the system has the higher energy conversion coefficient of 1.49 and the higher energy density of 1216.6 kJ/kg-zeolite.The change laws of system performances,such as energy generated,energy conversion coefficient and energy density,with key parameters during discharging process are revealed.The study provides a way for efficient utilization of low and medium grade heat energy.
基金Supported by National Key Basic Research and Development Program(973 Program) (2003CB415205),the National Natural Science Foundation of China(50479036)
文摘The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of reformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis- charge and discharge process are comprehensively analyzed according to the experimental data.It was found that the channel would be widened as the river slope or discharge increased and grain s...
基金supported by the National Basic Research Program of China(973Program:2012CB955604)National Natural Science Foundation of China(Nos.40975038and40830106)+5 种基金the CMA Program(GYHY200906008)the financial support provided by the China Scholarship Counciljointly supported by the 973 Program of China(2010CB950404)DOE grant DE-SC0005110National Science Foundation(NSF)grants ATM1034798NOAA grand NA10OAR4310200
文摘The standard deviation of the central Pacific sea surface temperature anomaly （SSTA） during the period from October to February shows that the central Pacific SSTA variation is primarily due to the occurrence of the Central Pacific E1 Nifio （CP-E1 Nifio） and has a connection with the subtropical air-sea interaction in the northeastern Pacific. After removing the influence of the Eastern Pacific E1 Nifio, an S-EOF analysis is conducted and the leading mode shows a clear seasonal SSTA evolving from the subtropical northeastern Pacific to the tropical central Pacific with a quasi-biennial period. The initial subtropical SSTA is generated by the wind speed decrease and surface heat flux increase due to a north Pacific anomalous cyclone. Such subtropical SSTA can further influence the establishment of the SSTA in the tropical central Pacific via the wind-evaporation-SST （WES） feedback. After established, the central equatorial Pacific SSTA can be strengthened by the zonal advective feedback and thermocline feedback, and develop into CP-E1 Nifio. However, as the thermocline feedback increases the SSTA cooling after the mature phase, the heat flux loss and the reversed zonal advective feedback can cause the phase transition of CP-EI Nifio. Along with the wind stress variability, the recharge （discharge） process occurs in the central （eastern） equatorial Pacific and such a process causes the phase consistency between the thermocline depth and SST anomalies, which presents a contrast to the original recharge/discharge theory.
基金supported by National Natural Science Foundation of China (No. 50374054)the Natural Science Foundation of Shanxi Province (No. 20031050)
文摘TiN/Ti multi-permeating alloying layer has been formed on the low carbon steel by means of the double glow-discharge plasma surface alloying technique and hollow-cathode effect. The alloying layer was detected by axiovert 25 CA optical microscope with computer analyzing software （LEC）, GDA-2 glow discharge spectroscopy （GDS）, X-ray diffraction （XRD） and galvanochemical method. The results showed that the thickness of TiN/Ti multi-permeating alloying layer was about 10μm, the content of Ti on the surface was up to 63.48 wt% and the content of N was up to 12.46 wt%. The atom Ti and N concentrations changed gradually across the depth of the alloying layer and the preferred orientation of TiN/Ti alloying layer was crystal surface （200）. The multi-permeating alloying layer and substrate were combined through metallurgy. The surface appearances of the multi-permeating alloying layer were uniform and of a compact cellular structure. The hardness of the surface was about 1600-3000 HV0.1. The corrosion resistance of the permeating TiN/Ti alloying layer in 0.5 mol/L H2SO4 solution was greatly increased and the corrosion rate was only 0.3082 g/m^2. h.
基金supported by National Natural Science Foundation of China(No.11975038)。
文摘In this study,a code,named Peking University Helicon Discharge(PHD),which can simulate helicon discharge processes under both a background magnetic field greater than 500 G and a pressure less than 1 Pa,is developed.In the code,two fluid equations are used.The PHD simulations led to two important findings:(1)the temporal evolution of plasma density with the background magnetic field exhibits a second rapid increase(termed as the second density jump),similar to the transition of modes in helicon plasmas;(2)in the presence of a magnetic field,the peak positions of electron power absorption appeared near the central axis,unlike in the case of no magnetic field.These results may lead to an enhanced understanding of the discharge mechanism.
基金The National Natural Science Foundation of China(52376040)Nanjing New Research and Development Institutions Joint Technology Research Project(202304008)+2 种基金Beijing Nova Program(2023048447),National Key R&D Program of China(2023YFB2406500)The International Partnership Program of Chinese Academy of Sciences(Grant No.117GJHZ2023093MI,117GJHZ2024010MI)“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences,Grant No.XDAXDA0400100.
文摘Compressed air energy storage(CAES)is considered as one of the most promising large scale energy storage technologies for the electrical grid with high penetration of renewable energy.CAES systems are required to operate under complex conditions because of the pressure change in the air storage chamber and input/output power changes considering the fluctuated renewable generation and the mismatch between energy supply and demand.A dynamic operation configuration was proposed to satisfy the adjustment of off-design conditions of CAES systems and frequency management auxiliary service market.To regulate the inlet pressure of turbines and meet the output power demand for better performance,a thermodynamic model of a CAES discharging system with thermal storage and the pressure control unit(SER)was established.The control strategy of setting adjustment width instead of single instruction curve is proposed.Then,the dynamic operation parameters including pressure,mass flow rate,and exergy change during discharging processes were investigated.The superiority of the control accuracy and efficiency was demonstrated over single throttle valve through valve characterization studies.The SER system improves control accuracy by decoupling pressure and flow rate changes in dynamic operation,solving the problem of difficult control and low accuracy of traditional throttle valves.The expansion tank in SER serves as a pressure buffer and heat exchanger with the environment,reducing energy loss during fluid flow.Furthermore,the effect of the expansion tank volume of switch expansion reduction in exergy destruction were assessed.For a 10 MW/60MWh system with dynamic load to meet the requirements of the unit to participate in the frequency modulation auxiliary service market,the optimal added expansion tank volume is about 70m3.The optimization method of control strategy of SER system is also explored.The proposed optimized SER system of volume and control strategy can smoothly regulate the inlet pressure of the expander.When the adjustment width is 3bar,the frequency is 50%decreased,meanwhile,the on–off action time is more evenness,which ensures the stable and efficient operation of the CAES system and improves the comprehensive performance of the system.
基金supported by the National Natural Science Foundation of China(Grant Nos.21922807 and 22078193)Double Thousand Plan of Jiangxi Province(461654,jxsq2019102052)Shaanxi Provincial Key Research and Development Program(Grant No.2020ZDLGY11-06)。
文摘Water pollution caused by dye is a serious challenge.Herein,we use a novel discharge process to functionalize carbon nanotube(CNT)by COOH groups to form CNT30 for removing methyl red(MR)from water.By pristine CNT,75%MR is removed in 60 min,with an adsorption capacity of 68.44 mg g-1.By CNT30,85%MR is fast removed in only 5 min,and the removal efficiency reaches to 95%after 30 min,with an adsorption capacity of80.33 mg g-1.Thus,a higher MR removal efficiency is achieved in a much shorter time on CNT30.Moreover,CNT30 has an outstanding reusability,with the MR removal efficiency decreasing by only 7%after ten cycles.The COOH groups on CNT30 improve the hydrophilicity of CNT30,thus promoting the interaction of MR in water with CNT30.The hydrogen bonding and electrostatic interaction of MR with the COOH groups on CNT30 could be the force to drive MR adsorption on CNT30.The higher COOH content could be the origin for the better performance of CNT30 in removing dye from water.The discharge process developed herein is operated in O2,without using harmful substances,and the COOH content on CNT can be efficiently tuned by simply changing discharge time.This is different from the chemical modification widely used to functionalize CNT by strong oxidants,e.g.,HNO_(3).The present work is of great significance to realize green construction of materials for more efficiently removing dye from water.
