In wind power transmission via modular multilevel converter based high voltage direct current(MMCHVDC)systems,under traditional control strategies,MMC-HVDCcannot provide inertia support to the receiving-end grid(REG)d...In wind power transmission via modular multilevel converter based high voltage direct current(MMCHVDC)systems,under traditional control strategies,MMC-HVDCcannot provide inertia support to the receiving-end grid(REG)during disturbances.Moreover,due to the frequency decoupling between the two ends of the MMCHVDC,the sending-end wind farm(SEWF)cannot obtain the frequency variation information of the REG to provide inertia response.Therefore,this paper proposes a novel coordinated source-network-storage inertia control strategy based on wind power transmission via MMC-HVDC system.First,the grid-side MMC station(GS-MMC)maps the frequency variations of the REG to direct current(DC)voltage variations through the frequency mapping control,and uses submodule capacitor energy to provide inertial power.Then,the wind farm-side MMC station(WF-MMC)restores the DC voltage variations to frequency variations through the frequency restoration control and power loss compensation,providing real-time frequency information for the wind farm.Finally,based on real-time frequency information,thewind farmutilizes the rotor kinetic energy and energy storage to provide fast and lasting power support through the wind-storage coordinated inertia control strategy.Meanwhile,when the wind turbines withdraw from the inertia response phase,the energy storage can increase the power output to compensate for the power deficit,preventing secondary frequency drops.Furthermore,this paper uses small-signal analysis to determine the appropriate values for the key parameters of the proposed control strategy.A simulation model of the wind power transmission via MMCHVDC system is built in MATLAB/Simulink environment to validate and evaluate the proposed method.The results show that the proposed coordinated control strategy can effectively improve the system inertia level and avoid the secondary frequency drop under the load sudden increase condition.展开更多
The integration of substantial renewable energy and controllable resources disrupts the supply-demand balance in distribution grids.Secure operations are dependent on the participation of user-side resources in demand...The integration of substantial renewable energy and controllable resources disrupts the supply-demand balance in distribution grids.Secure operations are dependent on the participation of user-side resources in demand response at both the day-ahead and intraday levels.Current studies typically overlook the spatial--temporal variations and coordination between these timescales,leading to significant day-ahead optimization errors,high intraday costs,and slow convergence.To address these challenges,we developed a multiagent,multitimescale aggregated regulation method for spatial--temporal coordinated demand response of user-side resources.Firstly,we established a framework considering the spatial--temporal coordinated characteristics of user-side resources with the objective to min-imize the total regulation cost and weighted sum of distribution grid losses.The optimization problem was then solved for two different timescales:day-ahead and intraday.For the day-ahead timescale,we developed an improved particle swarm optimization(IPSO)algo-rithm that dynamically adjusts the number of particles based on intraday outcomes to optimize the regulation strategies.For the intraday timescale,we developed an improved alternating direction method of multipliers(IADMM)algorithm that distributes tasks across edge distribution stations,dynamically adjusting penalty factors by using historical day-ahead data to synchronize the regulations and enhance precision.The simulation results indicate that this method can fully achieve multitimescale spatial--temporal coordinated aggregated reg-ulation between day-ahead and intraday,effectively reduce the total regulation cost and distribution grid losses,and enhance smart grid resilience.展开更多
To guarantee a unified response to disasters, humanitarian organizations work together via the United Nations Office for the Coordination of Humanitarian Affairs (OCHA). Although the OCHA has made great strides to imp...To guarantee a unified response to disasters, humanitarian organizations work together via the United Nations Office for the Coordination of Humanitarian Affairs (OCHA). Although the OCHA has made great strides to improve its information management and increase the availability of accurate, real-time data for disaster and humanitarian response teams, significant gaps persist. There are inefficiencies in the emergency management of data at every stage of its lifecycle: collection, processing, analysis, distribution, storage, and retrieval. Disaster risk reduction and disaster risk management are the two main tenets of the United Nations’ worldwide plan for disaster management. Information systems are crucial because of the crucial roles they play in capturing, processing, and transmitting data. The management of information is seldom discussed in published works. The goal of this study is to employ qualitative research methods to provide insight by facilitating an expanded comprehension of relevant contexts, phenomena, and individual experiences. Humanitarian workers and OCHA staffers will take part in the research. The study subjects will be chosen using a random selection procedure. Online surveys with both closed- and open-ended questions will be used to compile the data. UN OCHA offers a structure for the handling of information via which all humanitarian actors may contribute to the overall response. This research will enable the UN Office for OCHA better gather, process, analyze, disseminate, store, and retrieve data in the event of a catastrophe or humanitarian crisis.展开更多
Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on...Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW （East -West） direction, NS （South- North） direction and perpendicular to the surface （z） direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations： （1） the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; （2） response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and （3） the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion.展开更多
Spherical-symmetric steady-state response problem of piezoelectric spherical shell in the absence of body force and free charges is discussed. The steady-state response solutions of mechanical displacement, stresses, ...Spherical-symmetric steady-state response problem of piezoelectric spherical shell in the absence of body force and free charges is discussed. The steady-state response solutions of mechanical displacement, stresses, strains, potential and electric displacement were derived Sram constitutive relations, geometric and motion equations for the piezoelectric medium under external excitation (i.e. applied surface traction and potential) in spherical coordinate system. As an application of the? general solutions, the problem of an elastic spherical shell with piezoelectric actuator and sensor layers was solved. The results could provide good theoretical basis for the spherical-symmetric dynamic control problem of piezoelectric intelligent structure. Furthermore, the solutions can serve as reference for the research of general dynamic control problem.展开更多
This paper presents a transactive demand response(TDR)scheme for a network of residential customers with generation assets that emphasizes interoperability within a transactive energy architecture.A complete laborator...This paper presents a transactive demand response(TDR)scheme for a network of residential customers with generation assets that emphasizes interoperability within a transactive energy architecture.A complete laboratory-based implementation provides the first(to our knowledge)realization of a comprehensive TDR use case that is fully compliant with the Institute of Electrical and Electronics Engineers(IEEE)2030.5 standard,which addresses interoperability within a cybersecure smart energy profile(SEP)context.Verification is provided by a full system integration with commercial hardware using Internet Protocol(IP)-based(local area network(LAN)and Wi-Fi)communication protocols and transport layer security(TLS)1.2 cryptographic protocol,and validation is provided by emulation using extensive residential smart meter data.The demand response(DR)scheme is designed to accommodate privacy concerns,allows customers to select their DR compliance level,and provides incentives to maximize their participation.The proposed TDR scheme addresses privacy through the implementation of the SEP 2.0 messaging protocol between a transactive agent(TA)and home energy management system(HEMS)agents.Customer response is handled by a multi-input multi-output(MIMO)fuzzy controller that manages negotiation between the customer agent and the TA.We take a multi-agent system approach to neighborhood coordination,with the TA servicing multiple residences on a common transformer,and use a reward mechanism to maximize customer engagement during the event-based optimization.Based on a set of smart meter data acquired over an extended time period,we engage in multiple TDR scenarios,and demonstrate with a fully-functional IEEE 2030.5-compliant implementation that our scheme can reduce network peak power consumption by 22%under realistic conditions.展开更多
The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when analyzing the f...The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when analyzing the frequency dynamic progress in the island with large-capacity active-power shortage. In this paper, coupling effects of voltage and frequency are studied to indicate that initial reactive-power deficit and load characteristics have strong effects on the coupling effects of the voltage and frequency. Moreover, control effects of currently used under frequency load-shedding relays (UFLS) and under voltage load-shedding relays (UVLS) which are installed and executed independently are examined to find that it would sometimes cause excessive or inadequate control without considering the coupling, suggesting that it is necessary to develop coordinate control methods for voltage and frequency problems.展开更多
Erythrocyte tropomodulin（E-Tmod）is a capping protein at the slow-growing end of the actin filaments and regulates the length of the junctional complex in the erythrocyte membrane skeleton<sup>[1]</sup>.E...Erythrocyte tropomodulin（E-Tmod）is a capping protein at the slow-growing end of the actin filaments and regulates the length of the junctional complex in the erythrocyte membrane skeleton<sup>[1]</sup>.E-Tmod has two alternative promoters,P<sub>E0</sub>,and P<sub>E1</sub>,upstream of exons EO and E1,respectively.They drive the expression of two E-Tmod isoforms,E-Tmod41 and ETmod29,which play different yet coordinated roles in cytoskeleton reorganization<sup>[2]</sup>.This study aimed at investigating the expessions of the two E-Tmod isoforms response to the mechanical stresses,i.e.,shear stress and hydrostatic pressure.A cone-plate flow system and a hydrostatic pressure device were developed.Murine erythroleukemia（MEL）cells were subjected展开更多
With the increasing penetration of wind and solar energies,the accompanying uncertainty that propagates in the system places higher requirements on the expansion planning of power systems.A source-grid-load-storage co...With the increasing penetration of wind and solar energies,the accompanying uncertainty that propagates in the system places higher requirements on the expansion planning of power systems.A source-grid-load-storage coordinated expansion planning model based on stochastic programming was proposed to suppress the impact of wind and solar energy fluctuations.Multiple types of system components,including demand response service entities,converter stations,DC transmission systems,cascade hydropower stations,and other traditional components,have been extensively modeled.Moreover,energy storage systems are considered to improve the accommodation level of renewable energy and alleviate the influence of intermittence.Demand-response service entities from the load side are used to reduce and move the demand during peak load periods.The uncertainties in wind,solar energy,and loads were simulated using stochastic programming.Finally,the effectiveness of the proposed model is verified through numerical simulations.展开更多
As new power systems and dual carbon policies develop,virtual power plant cluster(VPPC)provides another reliable way to promote the efficient utilization of energy and solve environmental pollution problems.To solve t...As new power systems and dual carbon policies develop,virtual power plant cluster(VPPC)provides another reliable way to promote the efficient utilization of energy and solve environmental pollution problems.To solve the coordinated optimal operation and low-carbon economic operation problem in multi-virtual power plant,a multi-virtual power plant(VPP)electricity-carbon interaction optimal scheduling model considering integrated demand response(IDR)is proposed.Firstly,a multi-VPP electricity-carbon interaction framework is established.The interaction of electric energy and carbon quotas can realize energy complementarity,reduce energy waste and promote low-carbon operation.Secondly,in order to coordinate the multiple types of energy and load in VPPC to further achieve low-carbon operation,the IDR mechanism based on the user comprehensive satisfaction(UCS)of electricity,heat as well as hydrogen is designed,which can effectively maintain the UCS in the cluster within a relatively high range.Finally,the unit output scheme is formulated to minimize the total cost of VPPC and the model is solved using theCPLEX solver.The simulation results showthat the proposed method effectively promotes the coordinated operation among multi-VPP,increases the consumption rate of renewable energy sources and the economics of VPPC and reduces carbon emissions.展开更多
Abscisic acid(ABA)is an essential plant hormone that regulates multiple aspects of plant development and numerous abiotic stress responses(Cutler et al.,2010;Waadt et al.,2022).In fact,at the heart of plants'respo...Abscisic acid(ABA)is an essential plant hormone that regulates multiple aspects of plant development and numerous abiotic stress responses(Cutler et al.,2010;Waadt et al.,2022).In fact,at the heart of plants'responses to stresses such as salinity,drought,and hypertonic conditions,among others,is this phytohormone(Cutler et al.,2010;Waadt et al.,2022).展开更多
Since the implementation of the reform and opening-up policy,China has undergone a period of rapid development.However,this urban expansion has been accompanied by significant ecological challenges.Therefore,understan...Since the implementation of the reform and opening-up policy,China has undergone a period of rapid development.However,this urban expansion has been accompanied by significant ecological challenges.Therefore,understanding the relationship between urban expansion and ecological sustainability is crucial for future urban planning.This study analyzes land use data to investigate the spatiotemporal dynamics of urban agglomeration expansion from 2000 to 2020.Using MODIS satellite data,this study constructs a Remote Sensing Ecological Index(RSEI)model to assess ecological quality changes over the past two decades.Additionally,an improved coupling coordination model is applied to examine the interaction between urban expansion and ecological quality and to evaluate the spatiotemporal trends of their coordination.The results indicate that:①From 2000 to 2020,urban expansion in the Henan section of the Yellow River Basin followed a pattern of“growth-growthdecline”.Pattern recognition analysis indicated that both urban agglomerations and individual cities primarily expanded through edge extension and infill development,while enclave-style expansion occurred in only a small portion of the region.②Between 2000 and 2020,the ecological quality of urban agglomerations in the Henan section of the Yellow River Basin showed a slight improvement.RSEI values ranged from 0.4 to 0.7,indicating moderate ecological quality.Ecological quality exhibited a spatial pattern of being higher in the southwest and lower in the northeast.Significant declines in ecological quality were primarily concentrated in urban built-up areas,forming a patch-like distribution.Conversely,notable improvements in ecological quality occurred mainly in the mountainous regions of the southwest and north.③Between 2000 and 2020,the coupling coordination level of urban agglomerations showed an increasing trend.Coupling coordination values ranged from 0.248 to 0.734.Most cities were near an imbalance between urban expansion and ecological quality,while Zhengzhou was the only city to consistently maintain coordinated development over two decades.Spatially,highly imbalanced areas were mainly concentrated in the western and southern Henan sections,particularly in Sanmenxia and Luoyang.Conversely,areas with high coupling coordination were centered around Zhengzhou,showing a radial expansion pattern in recent years.展开更多
深度挖掘柔性资源的响应潜力,可以提升园区综合能源系统(Park Integrated Energy System,PIES)运行的经济性、灵活性与低碳性。为此,文章提出一种考虑供需灵活响应的PIES优化调度策略。首先,在分析设备动态能效特性的基础上,引入有机闪...深度挖掘柔性资源的响应潜力,可以提升园区综合能源系统(Park Integrated Energy System,PIES)运行的经济性、灵活性与低碳性。为此,文章提出一种考虑供需灵活响应的PIES优化调度策略。首先,在分析设备动态能效特性的基础上,引入有机闪蒸循环和电热锅炉建立热电联产(Combined Heat and Power,CHP)机组多模态且变工况运行的供给侧灵活响应模型;然后,基于多级阶梯激励补偿机制,在负荷侧建立削减、替代与转移柔性负荷差异化配比的电-冷-热多元需求响应模型;最后,以日运行成本最小为优化目标,构建PIES供需灵活响应的协调优化模型。仿真分析表明,文章所提策略不仅可以提高调度模型的准确度,还可以在促进风电消纳的同时,实现系统经济性、低碳性,供能可靠性、满意度的多维度优化平衡。展开更多
基金funded by State Grid Corporation of China Central Branch Technology Project(52140024000C).
文摘In wind power transmission via modular multilevel converter based high voltage direct current(MMCHVDC)systems,under traditional control strategies,MMC-HVDCcannot provide inertia support to the receiving-end grid(REG)during disturbances.Moreover,due to the frequency decoupling between the two ends of the MMCHVDC,the sending-end wind farm(SEWF)cannot obtain the frequency variation information of the REG to provide inertia response.Therefore,this paper proposes a novel coordinated source-network-storage inertia control strategy based on wind power transmission via MMC-HVDC system.First,the grid-side MMC station(GS-MMC)maps the frequency variations of the REG to direct current(DC)voltage variations through the frequency mapping control,and uses submodule capacitor energy to provide inertial power.Then,the wind farm-side MMC station(WF-MMC)restores the DC voltage variations to frequency variations through the frequency restoration control and power loss compensation,providing real-time frequency information for the wind farm.Finally,based on real-time frequency information,thewind farmutilizes the rotor kinetic energy and energy storage to provide fast and lasting power support through the wind-storage coordinated inertia control strategy.Meanwhile,when the wind turbines withdraw from the inertia response phase,the energy storage can increase the power output to compensate for the power deficit,preventing secondary frequency drops.Furthermore,this paper uses small-signal analysis to determine the appropriate values for the key parameters of the proposed control strategy.A simulation model of the wind power transmission via MMCHVDC system is built in MATLAB/Simulink environment to validate and evaluate the proposed method.The results show that the proposed coordinated control strategy can effectively improve the system inertia level and avoid the secondary frequency drop under the load sudden increase condition.
基金supported by Science and Technology Program of China Southern Power Grid Corporation under grant number 036000KK52222004(GDKJXM20222117)National Key R&D Program of China for International S&T Cooperation Projects(2019YFE0118700).
文摘The integration of substantial renewable energy and controllable resources disrupts the supply-demand balance in distribution grids.Secure operations are dependent on the participation of user-side resources in demand response at both the day-ahead and intraday levels.Current studies typically overlook the spatial--temporal variations and coordination between these timescales,leading to significant day-ahead optimization errors,high intraday costs,and slow convergence.To address these challenges,we developed a multiagent,multitimescale aggregated regulation method for spatial--temporal coordinated demand response of user-side resources.Firstly,we established a framework considering the spatial--temporal coordinated characteristics of user-side resources with the objective to min-imize the total regulation cost and weighted sum of distribution grid losses.The optimization problem was then solved for two different timescales:day-ahead and intraday.For the day-ahead timescale,we developed an improved particle swarm optimization(IPSO)algo-rithm that dynamically adjusts the number of particles based on intraday outcomes to optimize the regulation strategies.For the intraday timescale,we developed an improved alternating direction method of multipliers(IADMM)algorithm that distributes tasks across edge distribution stations,dynamically adjusting penalty factors by using historical day-ahead data to synchronize the regulations and enhance precision.The simulation results indicate that this method can fully achieve multitimescale spatial--temporal coordinated aggregated reg-ulation between day-ahead and intraday,effectively reduce the total regulation cost and distribution grid losses,and enhance smart grid resilience.
文摘To guarantee a unified response to disasters, humanitarian organizations work together via the United Nations Office for the Coordination of Humanitarian Affairs (OCHA). Although the OCHA has made great strides to improve its information management and increase the availability of accurate, real-time data for disaster and humanitarian response teams, significant gaps persist. There are inefficiencies in the emergency management of data at every stage of its lifecycle: collection, processing, analysis, distribution, storage, and retrieval. Disaster risk reduction and disaster risk management are the two main tenets of the United Nations’ worldwide plan for disaster management. Information systems are crucial because of the crucial roles they play in capturing, processing, and transmitting data. The management of information is seldom discussed in published works. The goal of this study is to employ qualitative research methods to provide insight by facilitating an expanded comprehension of relevant contexts, phenomena, and individual experiences. Humanitarian workers and OCHA staffers will take part in the research. The study subjects will be chosen using a random selection procedure. Online surveys with both closed- and open-ended questions will be used to compile the data. UN OCHA offers a structure for the handling of information via which all humanitarian actors may contribute to the overall response. This research will enable the UN Office for OCHA better gather, process, analyze, disseminate, store, and retrieve data in the event of a catastrophe or humanitarian crisis.
基金National Technology Research and Development Program of the Ministry of Science and Technology of China under Grant No.2015BAK17B03National Natural Science Foundation of China(General Program)under Grant No.51278152+1 种基金National Science & Technology Pillar Program(2015BAK17B06)Program for Innovation Research Team in China Earthquake Administration
文摘Due to the randomness of earthquake wave magnitude and direction, and the uncertain direction of strong axis and weak axis in the construction of engineering structures, the effect of the direction of ground motion on a structure are studied herein. Ground motion records usually contain three vertical ground motion data, which are obtained by sensors arranged in accordance with the EW （East -West） direction, NS （South- North） direction and perpendicular to the surface （z） direction, referring to the construction standard of seismic stations. The seismic records in the EW and NS directions are converted to Cartesian coordinates in accordance with the rotation of θ = 0°-180°, and consequently, a countless group of new ground motion time histories are obtained. Then, the characteristics of the ground motion time history and response spectrum of each group were studied, resulting in the following observations： （1） the peak and phase of ground motion are changed with the rotation of direction θ, so that the direction θ of the maximum peak ground motion can be determined; （2） response spectrum values of each group of ground motions change along with the direction θ, and their peak, predominant period and declining curve are also different as the changes occur; then, the angle θ in the direction of the maximum peak value or the widest predominant period can be determined; and （3） the seismic response of structures with different directions of ground motion inputs has been analyzed under the same earthquake record, and the results show the difference. For some ground motion records, such as the Taft seismic wave, these differences are significant. Next, the Lushan middle school gymnasium structure was analyzed and the calculation was checked using the proposed method, where the internal force of the upper space truss varied from 25% to 28%. The research results presented herein can be used for reference in choosing the ground motion when checking the actual damage to structures following earthquakes and explaining the seismic damage. Meanwhile, it also provides a reference value for research into the most severe ground motion.
文摘Spherical-symmetric steady-state response problem of piezoelectric spherical shell in the absence of body force and free charges is discussed. The steady-state response solutions of mechanical displacement, stresses, strains, potential and electric displacement were derived Sram constitutive relations, geometric and motion equations for the piezoelectric medium under external excitation (i.e. applied surface traction and potential) in spherical coordinate system. As an application of the? general solutions, the problem of an elastic spherical shell with piezoelectric actuator and sensor layers was solved. The results could provide good theoretical basis for the spherical-symmetric dynamic control problem of piezoelectric intelligent structure. Furthermore, the solutions can serve as reference for the research of general dynamic control problem.
基金Natural Sciences and Engineering Council of Canada(CRDPJ 477238-14)and Hydro Ottawa。
文摘This paper presents a transactive demand response(TDR)scheme for a network of residential customers with generation assets that emphasizes interoperability within a transactive energy architecture.A complete laboratory-based implementation provides the first(to our knowledge)realization of a comprehensive TDR use case that is fully compliant with the Institute of Electrical and Electronics Engineers(IEEE)2030.5 standard,which addresses interoperability within a cybersecure smart energy profile(SEP)context.Verification is provided by a full system integration with commercial hardware using Internet Protocol(IP)-based(local area network(LAN)and Wi-Fi)communication protocols and transport layer security(TLS)1.2 cryptographic protocol,and validation is provided by emulation using extensive residential smart meter data.The demand response(DR)scheme is designed to accommodate privacy concerns,allows customers to select their DR compliance level,and provides incentives to maximize their participation.The proposed TDR scheme addresses privacy through the implementation of the SEP 2.0 messaging protocol between a transactive agent(TA)and home energy management system(HEMS)agents.Customer response is handled by a multi-input multi-output(MIMO)fuzzy controller that manages negotiation between the customer agent and the TA.We take a multi-agent system approach to neighborhood coordination,with the TA servicing multiple residences on a common transformer,and use a reward mechanism to maximize customer engagement during the event-based optimization.Based on a set of smart meter data acquired over an extended time period,we engage in multiple TDR scenarios,and demonstrate with a fully-functional IEEE 2030.5-compliant implementation that our scheme can reduce network peak power consumption by 22%under realistic conditions.
文摘The voltage and frequency dynamics interact with each other in the island after splitting. The current frequency response model without considering the voltage effect would bring remarkable errors when analyzing the frequency dynamic progress in the island with large-capacity active-power shortage. In this paper, coupling effects of voltage and frequency are studied to indicate that initial reactive-power deficit and load characteristics have strong effects on the coupling effects of the voltage and frequency. Moreover, control effects of currently used under frequency load-shedding relays (UFLS) and under voltage load-shedding relays (UVLS) which are installed and executed independently are examined to find that it would sometimes cause excessive or inadequate control without considering the coupling, suggesting that it is necessary to develop coordinate control methods for voltage and frequency problems.
基金supported by Natural Science Foundation of China(No.31170886)
文摘Erythrocyte tropomodulin（E-Tmod）is a capping protein at the slow-growing end of the actin filaments and regulates the length of the junctional complex in the erythrocyte membrane skeleton<sup>[1]</sup>.E-Tmod has two alternative promoters,P<sub>E0</sub>,and P<sub>E1</sub>,upstream of exons EO and E1,respectively.They drive the expression of two E-Tmod isoforms,E-Tmod41 and ETmod29,which play different yet coordinated roles in cytoskeleton reorganization<sup>[2]</sup>.This study aimed at investigating the expessions of the two E-Tmod isoforms response to the mechanical stresses,i.e.,shear stress and hydrostatic pressure.A cone-plate flow system and a hydrostatic pressure device were developed.Murine erythroleukemia（MEL）cells were subjected
基金supported by Science and Technology Project of SGCC(SGSW0000FZGHBJS2200070)。
文摘With the increasing penetration of wind and solar energies,the accompanying uncertainty that propagates in the system places higher requirements on the expansion planning of power systems.A source-grid-load-storage coordinated expansion planning model based on stochastic programming was proposed to suppress the impact of wind and solar energy fluctuations.Multiple types of system components,including demand response service entities,converter stations,DC transmission systems,cascade hydropower stations,and other traditional components,have been extensively modeled.Moreover,energy storage systems are considered to improve the accommodation level of renewable energy and alleviate the influence of intermittence.Demand-response service entities from the load side are used to reduce and move the demand during peak load periods.The uncertainties in wind,solar energy,and loads were simulated using stochastic programming.Finally,the effectiveness of the proposed model is verified through numerical simulations.
基金supported by the National Natural Science Foundation of China (NSFC) (Grant No.52107107).
文摘As new power systems and dual carbon policies develop,virtual power plant cluster(VPPC)provides another reliable way to promote the efficient utilization of energy and solve environmental pollution problems.To solve the coordinated optimal operation and low-carbon economic operation problem in multi-virtual power plant,a multi-virtual power plant(VPP)electricity-carbon interaction optimal scheduling model considering integrated demand response(IDR)is proposed.Firstly,a multi-VPP electricity-carbon interaction framework is established.The interaction of electric energy and carbon quotas can realize energy complementarity,reduce energy waste and promote low-carbon operation.Secondly,in order to coordinate the multiple types of energy and load in VPPC to further achieve low-carbon operation,the IDR mechanism based on the user comprehensive satisfaction(UCS)of electricity,heat as well as hydrogen is designed,which can effectively maintain the UCS in the cluster within a relatively high range.Finally,the unit output scheme is formulated to minimize the total cost of VPPC and the model is solved using theCPLEX solver.The simulation results showthat the proposed method effectively promotes the coordinated operation among multi-VPP,increases the consumption rate of renewable energy sources and the economics of VPPC and reduces carbon emissions.
基金Work in the Gregory lab is supported by grants IOS-2023310 and MCB-2427729 from the United States National Science Foundation.
文摘Abscisic acid(ABA)is an essential plant hormone that regulates multiple aspects of plant development and numerous abiotic stress responses(Cutler et al.,2010;Waadt et al.,2022).In fact,at the heart of plants'responses to stresses such as salinity,drought,and hypertonic conditions,among others,is this phytohormone(Cutler et al.,2010;Waadt et al.,2022).
基金State Key Laboratory of Spatial Datum(No.SKLSD2025-ZZ-17)National Natural Science Foundation of China(No.U21A2014)+2 种基金High-Resolution Satellite Project of the State Administration of Science,Technology,and Industry for National Defense of the PRC(No.80Y50G19-9001-22/23)National Science and Technology Platform Construction Project(No.2005DKA32300)Major Research Projects of the Ministry of Education(No.16JJD770019).
文摘Since the implementation of the reform and opening-up policy,China has undergone a period of rapid development.However,this urban expansion has been accompanied by significant ecological challenges.Therefore,understanding the relationship between urban expansion and ecological sustainability is crucial for future urban planning.This study analyzes land use data to investigate the spatiotemporal dynamics of urban agglomeration expansion from 2000 to 2020.Using MODIS satellite data,this study constructs a Remote Sensing Ecological Index(RSEI)model to assess ecological quality changes over the past two decades.Additionally,an improved coupling coordination model is applied to examine the interaction between urban expansion and ecological quality and to evaluate the spatiotemporal trends of their coordination.The results indicate that:①From 2000 to 2020,urban expansion in the Henan section of the Yellow River Basin followed a pattern of“growth-growthdecline”.Pattern recognition analysis indicated that both urban agglomerations and individual cities primarily expanded through edge extension and infill development,while enclave-style expansion occurred in only a small portion of the region.②Between 2000 and 2020,the ecological quality of urban agglomerations in the Henan section of the Yellow River Basin showed a slight improvement.RSEI values ranged from 0.4 to 0.7,indicating moderate ecological quality.Ecological quality exhibited a spatial pattern of being higher in the southwest and lower in the northeast.Significant declines in ecological quality were primarily concentrated in urban built-up areas,forming a patch-like distribution.Conversely,notable improvements in ecological quality occurred mainly in the mountainous regions of the southwest and north.③Between 2000 and 2020,the coupling coordination level of urban agglomerations showed an increasing trend.Coupling coordination values ranged from 0.248 to 0.734.Most cities were near an imbalance between urban expansion and ecological quality,while Zhengzhou was the only city to consistently maintain coordinated development over two decades.Spatially,highly imbalanced areas were mainly concentrated in the western and southern Henan sections,particularly in Sanmenxia and Luoyang.Conversely,areas with high coupling coordination were centered around Zhengzhou,showing a radial expansion pattern in recent years.
文摘深度挖掘柔性资源的响应潜力,可以提升园区综合能源系统(Park Integrated Energy System,PIES)运行的经济性、灵活性与低碳性。为此,文章提出一种考虑供需灵活响应的PIES优化调度策略。首先,在分析设备动态能效特性的基础上,引入有机闪蒸循环和电热锅炉建立热电联产(Combined Heat and Power,CHP)机组多模态且变工况运行的供给侧灵活响应模型;然后,基于多级阶梯激励补偿机制,在负荷侧建立削减、替代与转移柔性负荷差异化配比的电-冷-热多元需求响应模型;最后,以日运行成本最小为优化目标,构建PIES供需灵活响应的协调优化模型。仿真分析表明,文章所提策略不仅可以提高调度模型的准确度,还可以在促进风电消纳的同时,实现系统经济性、低碳性,供能可靠性、满意度的多维度优化平衡。
