As the power system transitions to a new green and low-carbon paradigm,the penetration of renewable energy in China’s power system is gradually increasing.However,the variability and uncertainty of renewable energy o...As the power system transitions to a new green and low-carbon paradigm,the penetration of renewable energy in China’s power system is gradually increasing.However,the variability and uncertainty of renewable energy output limit its profitability in the electricity market and hinder its market-based integration.This paper first constructs a wind-solar-thermalmulti-energy complementary system,analyzes its external game relationships,and develops a bi-level market optimization model.Then,it considers the contribution levels of internal participants to establish a comprehensive internal distribution evaluation index system.Finally,simulation studies using the IEEE 30-bus system demonstrate that the multi-energy complementary system stabilizes nodal outputs,enhances the profitability of market participants,and promotes the market-based integration of renewable energy.展开更多
The multi-energy complementary distributed energy system (MCDES) covers a variety of energy forms, involves complex operation modes, and contains a wealth of control equipment and coupling links. It can realize the co...The multi-energy complementary distributed energy system (MCDES) covers a variety of energy forms, involves complex operation modes, and contains a wealth of control equipment and coupling links. It can realize the complementary and efficient use of different types of energy, which is the basic component of the physical layer of the Energy Internet. In this paper, aiming at the demand of the energy application for towns, a distributed energy system based on multi-energy complementary is constructed. Firstly, the supply condition of the distributed energy for the demonstration project is analyzed, and the architecture of the multi-energy complementary distributed energy system is established. Then the regulation strategy of the multi-energy complementary distributed energy system is proposed. Finally, an overall system scheme for the multi-energy complementary distributed energy system suitable for towns is developed, which provides a solid foundation for the development and promotion of the multi-energy complementary distributed energy system.展开更多
Multi-energy complementary distributed energy system(MECDES)is an important development direction for the energy system.It has the advantages of energy conservation and environmental protection and has great potential...Multi-energy complementary distributed energy system(MECDES)is an important development direction for the energy system.It has the advantages of energy conservation and environmental protection and has great potential to realize efficient energy cascade utilization through the energy conversion and utilization of cooling,heating,and power in place,achieving a user-oriented energy supply.The present study thoroughly reviews the current research status and puts forward the key scientific issues that urgently need to be resolved by investigating the problems and challenges of the MECDES from the perspectives of the characterization of the energetic mass-energy potential,the synergistic transformation and energy-potential coupling mechanism of multi-energy complementation,energy quality improvement and storage,and proactive regulation of the MECDES.Furthermore,the latest research progress of the MECDES for trickling the key scientific issues is comprehensively presented by proposing the distributed energy system with the complementation of multi-energy sources,developing novel ways of the energy potential coupling and energy cascaded comprehensive utilization of multi-energy complementation,proposing a new theory of multi-energy complementation and energy potential coupling and a new mechanism of source complementation,processing matching and thermodynamic cycle system collaborative conversion of both the fossil energy and renewable energy,and developing a new method of proactive adjust and control for adapting to fluctuating energy input and various energy load demands.Finally,the prospects and recommendations for the future research and development direction of MECDES are provided.展开更多
This paper develops an advanced framework for the operational optimization of integrated multi-energy systems that encompass electricity,gas,and heating networks.Introducing a cutting-edge stochastic gradient-enhanced...This paper develops an advanced framework for the operational optimization of integrated multi-energy systems that encompass electricity,gas,and heating networks.Introducing a cutting-edge stochastic gradient-enhanced distributionally robust optimization approach,this study integrates deep learning models,especially generative adversarial networks,to adeptly handle the inherent variability and uncertainties of renewable energy and fluctuating consumer demands.The effectiveness of this framework is rigorously tested through detailed simulations mirroring real-world urban energy consumption,renewable energy production,and market price fluctuations over an annual period.The results reveal substantial improvements in the resilience and efficiency of the grid,achieving a reduction in power distribution losses by 15%and enhancing voltage stability by 20%,markedly outperforming conventional systems.Additionally,the framework facilitates up to 25%in cost reductions during peak demand periods,significantly lowering operational costs.The adoption of stochastic gradients further refines the framework’s ability to continually adjust to real-time changes in environmental and market conditions,ensuring stable grid operations and fostering active consumer engagement in demand-side management.This strategy not only aligns with contem-porary sustainable energy practices but also provides scalable and robust solutions to pressing challenges in modern power network management.展开更多
The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency,making it imperative to address the challenge of efficiently and accurately machining film coo...The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency,making it imperative to address the challenge of efficiently and accurately machining film cooling holes.It has been demonstrated that conventional long-pulse lasers are incapable of meeting the elevated quality surface finish requirements for these holes,a consequence of the severe thermal defects.The employment of backside water-assisted laser drilling technology confers a number of distinct advantages in terms of mitigating laser thermal damage,thus representing a highly promising solution to this challenge.However,significant accumulation of bubbles and machining products during the backside water-assisted laser drilling process has been demonstrated to have a detrimental effect on laser transmission and machining stability,thereby reducing machining quality.In order to surmount these challenges,a novel method has been proposed,namely an ultrasonic shock water flow-assisted picosecond laser drilling technique.Numerical models for ultrasonic acoustic streaming and particle tracking for machining product transport have been established to investigate the mechanism.The simulation results demonstrated that the majority of the machining products could rapidly move away from the machining area because of the action of acoustic streaming,thereby avoiding the accumulation of bubbles and products.Subsequent analysis,comparing the process performance in micro-hole machining,confirmed that the ultrasonic field could effectively eliminate bubble and chip accumulation,thus significantly improving micro-hole quality.Furthermore,the impact of ultrasonic and laser parameters on micro-hole quality under varying machining methods was thoroughly investigated.The findings demonstrated that the novel methodology outlined in this study yielded superior-quality micro-holes at elevated ultrasonic and laser power levels,in conjunction with reduced laser frequency and scanning velocity.The taper of the micro-holes produced by the new method was reduced by more than 25%compared with the other conventional methods.展开更多
With the rapid growth of photovoltaic integration,the volatility and uncertainty of intermittent photovoltaic injection will dramatically reduce system operation reliability from the generation side.The system operato...With the rapid growth of photovoltaic integration,the volatility and uncertainty of intermittent photovoltaic injection will dramatically reduce system operation reliability from the generation side.The system operator may face certain financial risks brought by unexpected power failure under low operation reliability.Therefore,maintaining sufficient power reserve to meet system operation reliability and reduce risk,especially in an isolated system,is essential.However,the traditional reserve preparation strategy fails to consider the uncertainties of the power generation under the high penetration levels of emerging renewable energy resources.A novel reserve preparation strategy for an isolated system is developed in this paper using a twostage model.In the first stage,the optimal hourly scheduling of an isolated system is determined.In the second stage,a minute level conditional value-at-risk(CVaR)based model is established where the uncertainty of the reserve requirement is introduced with the chance constraint.The proposed discretized step transformation(DST)and subtraction type convolution(STC)methods are utilized to convert the model into mixedinteger linear programming,and finally solved by applying the CPLEX solver.The IEEE 39-bus system is used as the test case to validate the feasibility and effectiveness of the proposed two-stage model.展开更多
The multi-energy complementary ecosystem is an important form of the modern energy system.However,standardized evaluation criteria and the corresponding method framework have not yet been formed,resulting in unclear s...The multi-energy complementary ecosystem is an important form of the modern energy system.However,standardized evaluation criteria and the corresponding method framework have not yet been formed,resulting in unclear standards and irregular processes of its construction.To cope with this issue,a novel comprehensive evaluation framework for multi-energy complementary ecosystems is proposed in this study.First,a 5D comprehensive evaluation criteria system,including environment,economy,technology,safety and systematicness,is constructed.Then,a novel multicriteria decision-making model integrating an analytic network process,entropy and preference-ranking organization method for enrichment evaluation under an intuitional fuzzy environment is proposed.Finally,four practical cases are used for model testing and empirical analysis.The results of the research show that the unit cost of the energy supply and the internal rate of return indexes have the highest weights of 0.142 and 0.010,respectively.It means that they are the focus in the construction of a multi-energy complementary ecosystem.The net flows of four cases are 0.015,0.123,-0.132 and-0.005,indicating that cases with a variety of energy supply forms and using intelligent management and control platforms to achieve cold,heat and electrical coupling have more advantages.展开更多
Under the current long-term electricity market mechanism,new energy and thermal power face issues such as deviation assessment and compression of generation space.The profitability of market players is limited.Simulta...Under the current long-term electricity market mechanism,new energy and thermal power face issues such as deviation assessment and compression of generation space.The profitability of market players is limited.Simultaneously,the cooperation model among various energy sources will have a direct impact on the alliance’s revenue and the equity of income distribution within the alliance.Therefore,integrating new energy with thermal power units into an integrated multi-energy complementary system to participate in the long-term electricity market holds significant potential.To simulate and evaluate the benefits and internal distribution methods of a multi-energy complementary system participating in long-term market transactions,this paper first constructs a multi-energy complementary system integrated with new energy and thermal power generation units at the same connection point,and participates in the annual bilateral game as a unified market entity to obtain the revenue value under the annual bilateral market.Secondly,based on the entropy weight method,improvements are made to the traditional Shapley value distribution model,and an internal distribution model for multi-energy complementary systems with multiple participants is constructed.Finally,a Markov Decision Process(MDP)evaluation system is constructed for practical case verification.The research results show that the improved Shapley value distribution model achieves higher satisfaction,providing a reasonable allocation scheme for multi-energy complementary cooperation models.展开更多
In the background of the large-scale development and utilization of renewable energy,the joint operation of a variety of heterogeneous energy sources has become an inevitable development trend.However,the physical cha...In the background of the large-scale development and utilization of renewable energy,the joint operation of a variety of heterogeneous energy sources has become an inevitable development trend.However,the physical characteristics of different power sources and the inherent uncertainties of renewable energy power generation have brought difficulties to the planning,operation and control of power systems.For now,the utilization of multi-energy complementarity to promote energy transformation and improve the consumption of renewable energy has become a common understanding among researchers and the engineering community.This paper makes a review of the research on complementarity of new energy high proportion multi-energy systems from uncertainty modeling,complementary characteristics,planning and operation.We summarize the characteristics of the existing research and provide a reference for the further work.展开更多
With increasing interdependence among electricity,district heating,and natural gas systems in economy and physics,this paper focuses on the optimal bidding problem of a dominant gas-fired CHP unit in synchronized elec...With increasing interdependence among electricity,district heating,and natural gas systems in economy and physics,this paper focuses on the optimal bidding problem of a dominant gas-fired CHP unit in synchronized electricity-heat-gas markets with real-life step-wise energy offer format.Gas-fired CHP generators act as price makers and submit price-quantity offering curves in independently cleared electricity and district heating markets.A novel loss-embedded power flow model is proposed for market clearing which accounts for active power loss,congestion,reactive power flow,and voltage constraints.Adding penalty terms into the objective function eliminates additional binary variables,which eases computation burden.A two-stage trading mechanism is designed for gas-fired CHP generators to simultaneously participate in the multi-energy market.Based on a mathematical program with equilibrium constraints,an optimal bidding model is established in which the bilinear terms are eliminated by applying the binary expansion method.A diagonalization algorithm can be nested in the proposed trading mechanism if we intend to study the Nash equilibrium of the Nperson Cournot oligopoly market.Numerical tests with different scales are carried out to validate the proposed methodology in detail.展开更多
Complementary inverter is the basic unit for logic circuits,but the inverters based on full oxide thin-film transistors(TFTs)are still very limited.The next challenge is to realize complementary inverters using homoge...Complementary inverter is the basic unit for logic circuits,but the inverters based on full oxide thin-film transistors(TFTs)are still very limited.The next challenge is to realize complementary inverters using homogeneous oxide semiconduc-tors.Herein,we propose the design of complementary inverter based on full ZnO TFTs.Li-N dual-doped ZnO(ZnO:(Li,N))acts as the p-type channel and Al-doped ZnO(ZnO:Al)serves as the n-type channel for fabrication of TFTs,and then the complemen-tary inverter is produced with p-and n-type ZnO TFTs.The homogeneous ZnO-based complementary inverter has typical volt-age transfer characteristics with the voltage gain of 13.34 at the supply voltage of 40 V.This work may open the door for the development of oxide complementary inverters for logic circuits.展开更多
Gait,the unique pattern of how a person walks,has emerged as one of the most promising biometric features in modern intelligent sensing.Unlike fingerprints or facial characteristics,gait can be captured unobtrusively ...Gait,the unique pattern of how a person walks,has emerged as one of the most promising biometric features in modern intelligent sensing.Unlike fingerprints or facial characteristics,gait can be captured unobtrusively and at a distance,without requiring the subject’s awareness or cooperation.This makes it highly suitable for long-range surveillance,forensic investigation,and smart environments where contactless recognition is crucial.Traditional gait-recognition systems rely either on silhouettes,which capture the outer appearance of a person,or on skeletons,which describe the internal structure of human motion.Each modality provides only a partial understanding of gait.Silhouettes emphasize shape and contour but are easily distorted by clothing or carried objects;skeletons describe motion dynamics and limb coordination but lose discriminative details about body shape.This article presents the concept of Complementary Semantic Embedding(CSE),a unified framework that merges silhouette and skeleton information into a comprehensive semantic representation of human walking.By modeling the complementary nature of appearance and structure,the approach achieves more robust and accurate gait recognition even under challenging conditions.展开更多
Mild electrocatalytic nitrate reduction reaction(NO_(3)RR),driven by renewable electricity,is regarded as a desirable strategy for green ammonia synthesis and simultaneous removal of nitrogen-containing environmental ...Mild electrocatalytic nitrate reduction reaction(NO_(3)RR),driven by renewable electricity,is regarded as a desirable strategy for green ammonia synthesis and simultaneous removal of nitrogen-containing environmental pollutants.In view of different supply voltages from renewable energy sources,developing costeffective and efficient electrocatalysts with a wide operating potential window is very meaningful for practical application.However,currently reported catalysts usually need to introduce noble metals to synergistically achieve wide-potential selective ammonia synthesis from nitrate.In this work,we present for the first time a dual-transition-metal electrocatalyst(Fe_(3)C-CuO_(x)@NC,x=0,1)with wide-potential-adaptability for highly selective nitrate reduction to ammonia.Such Fe_(3)C-CuO_(x)@NC with spatially separated CuO_(x)and noblemetal-like Fe_(3)C nanoparticles encapsulated with nitrogen-doped graphitized carbon,exhibits outstanding performance in NO_(3)RR with desirable NH_(3)Faraday efficiency of more than 90%over a wide potential ranging from-0.2 V vs.RHE to-0.6 V vs.RHE,comparable to the reported noble metal catalysts.Different from common tandem catalysis,the wide-potential high ammonia selectivity of Fe_(3)C-CuO_(x)@NC is domina ntly ascribed to the complementary enhancement between CuO_(x)and Fe_(3)C,fully supported by results of experiments and density function theory calculations.CuO_(x)exhibit highly intrinsic nitrate reduction to nitrite to compensate for the slow potential determination step(^(*)NO_(3)→^(*)NO_(3)H)of Fe_(3)C,while Fe_(3)C,besides behaving like noble metals to supply adequate active hydrogens,has both good adsorption and reduction abilities for nitrite species to ammonia.Moreover,Fe_(3)C partially stabilizes active Cu^(0)/Cu^(+)sites,and the unique carbon-layer enca psulation structure effectively prevents the agglomeration and corrosion of metal nanoparticles during the electrocatalysis,thus maintaining good cyclic stability.The Zn-NO_(3)^(-)battery assembled with Fe_(3)C-CuO_(x)@NC can reach a high power density of 5.2 mW cm^(-2)at a potential of 1.0 V vs.Zn,with an NH_(3)Faraday efficiency of 92.4%at a current of 8.0 mA,proving its potential practical application.This advance provides unique insights into complementary catalysis mechanisms on multiple metal sites in NO_(3)RR,and offers a reference for the design of other transition metal electrocatalysts matching with renewable electricity.展开更多
Background:The use of complementary and alternative medicine(CAM)is common among individuals with underlying chronic illnesses.Objective:This systematic review and meta-analysis investigated the global prevalence and ...Background:The use of complementary and alternative medicine(CAM)is common among individuals with underlying chronic illnesses.Objective:This systematic review and meta-analysis investigated the global prevalence and patterns of CAM use among individuals with chronic kidney disease(CKD).Search strategy:PubMed,Embase,and Cumulative Index to Nursing and Allied Health Literature Plus were searched from inception until 26th February 2024.Inclusion criteria:Original articles reporting the use of at least one type of CAM among individuals aged above 18 years old and at all stages of CKD or undergoing any form of kidney replacement therapy.Data extraction and analysis:Two independent reviewers performed the literature screening.The data were extracted from the included studies by one reviewer and cross-checked by another.Discrepancies were resolved by discussion and consensus among two reviewers.Primary information included prevalence of CAM use,types of CAM used,reasons for CAM use,factors associated with CAM use,and disclosure to healthcare providers.Meta-analyses were performed to determine the pooled prevalence of CAM use and non-disclosure of CAM using a random effect model.Results:Forty-one studies were included in this systematic review and meta-analysis.The pooled prevalence of CAM use was 43%(95%confidence interval:34%,51%),I2=99.46%.The reasons for CAM use included treatment of underlying comorbidities,complications or symptoms,maintenance of general health,and treatment of CKD.Nutritional approaches were the most common CAM modality,with 412different herbal and dietary supplements reported;psychological and physical approaches included massage therapy,relaxation techniques,and mind–body practices;and other complementary health approaches such as homeopathy,traditional Chinese medicine,and Ayurvedic medicine were also frequently reported.Factors associated with CAM use included sociodemographic characteristics such as older age,female gender,or higher income;disease or therapy factors such as not having diabetes,relying on hemodialysis,or poor adherence to medication;and patient or internal factors such as positive attitude towards CAM and perceived safety of CAM.About 66%(61%,72%)of CAM users did not disclose the use of CAM to their healthcare providers.Conclusion:CAM use is prevalent among individuals with CKD,and healthcare providers should communicate openly and effectively to emphasize the rational use of CAM to avoid potential harm.展开更多
Low sidelobe waveform can reduce mutual masking between targets and increase the detection probability of weak targets.A low sidelobe waveform design method based on complementary amplitude coding(CAC)is proposed in t...Low sidelobe waveform can reduce mutual masking between targets and increase the detection probability of weak targets.A low sidelobe waveform design method based on complementary amplitude coding(CAC)is proposed in this paper,which can be used to reduce the sidelobe level of multiple waveforms.First,the CAC model is constructed.Then,the waveform design problem is transformed into a nonlinear optimization problem by constructing an objective function using the two indicators of peak-to-sidelobe ratio(PSLR)and integrated sidelobe ratio(ISLR).Finally,genetic algorithm(GA)is used to solve the optimization problem to get the best CAC waveforms.Simulations and experiments are conducted to verify the effectiveness of the proposed method.展开更多
This editorial is based on the network pharmacology and in vivo study by Qin et al,which investigated the potential therapeutic mechanisms of Panax ginseng(P.ginseng)in ulcerative colitis.The key findings from the stu...This editorial is based on the network pharmacology and in vivo study by Qin et al,which investigated the potential therapeutic mechanisms of Panax ginseng(P.ginseng)in ulcerative colitis.The key findings from the study included the identification of the targets of P.ginseng and ulcerative colitis,elucidation of mechanistic pathways,and in vivo validation of the pharmacological activity and therapeutic effect of panaxadiol,a key active component of P.ginseng.This editorial provides additional context regarding the evidence supporting the use of ginseng and other commonly used complementary therapies that clinicians may encounter.We also aim to highlight potential similarities between the mechanisms of popular complementary and conventional medical therapies.展开更多
The international scientific literature presents still incipient results regarding the management of cancer symptom clusters by oncology nursing,especially in pediatric oncology.This is a promising field of investigat...The international scientific literature presents still incipient results regarding the management of cancer symptom clusters by oncology nursing,especially in pediatric oncology.This is a promising field of investigation for clinical nurses and researchers,and when it is subsidized by medium-range theories,they co-rroborate the diagnoses and interventions of nursing in oncology,enhancing the science of nursing care.This minireview article aims to discuss the utilizing the hospital clowns as a complementary therapy,to enhance quality of life and reduce stress and fatigue in pediatric cancer patients.Overall,the evidence presented so far pointed out that complementary therapy might help improve the quality of life of pediatric cancer patients,and that complementary therapy usage should be part of a health comprehensive care model,delivering therapeutic approaches that might enhance the mind-body during a pediatric cancer patients’life span.The results of scientific investigations by nurses,particularly those linked to the basic sciences,play a critical role in advancing personalized care in pediatric integrative oncology.展开更多
基金funded by the National Key R&D Program of China,grant number 2019YFB1505400.
文摘As the power system transitions to a new green and low-carbon paradigm,the penetration of renewable energy in China’s power system is gradually increasing.However,the variability and uncertainty of renewable energy output limit its profitability in the electricity market and hinder its market-based integration.This paper first constructs a wind-solar-thermalmulti-energy complementary system,analyzes its external game relationships,and develops a bi-level market optimization model.Then,it considers the contribution levels of internal participants to establish a comprehensive internal distribution evaluation index system.Finally,simulation studies using the IEEE 30-bus system demonstrate that the multi-energy complementary system stabilizes nodal outputs,enhances the profitability of market participants,and promotes the market-based integration of renewable energy.
文摘The multi-energy complementary distributed energy system (MCDES) covers a variety of energy forms, involves complex operation modes, and contains a wealth of control equipment and coupling links. It can realize the complementary and efficient use of different types of energy, which is the basic component of the physical layer of the Energy Internet. In this paper, aiming at the demand of the energy application for towns, a distributed energy system based on multi-energy complementary is constructed. Firstly, the supply condition of the distributed energy for the demonstration project is analyzed, and the architecture of the multi-energy complementary distributed energy system is established. Then the regulation strategy of the multi-energy complementary distributed energy system is proposed. Finally, an overall system scheme for the multi-energy complementary distributed energy system suitable for towns is developed, which provides a solid foundation for the development and promotion of the multi-energy complementary distributed energy system.
基金supported by the Major Program of the National Natural Science Foundation of China(Grant No.52090060)。
文摘Multi-energy complementary distributed energy system(MECDES)is an important development direction for the energy system.It has the advantages of energy conservation and environmental protection and has great potential to realize efficient energy cascade utilization through the energy conversion and utilization of cooling,heating,and power in place,achieving a user-oriented energy supply.The present study thoroughly reviews the current research status and puts forward the key scientific issues that urgently need to be resolved by investigating the problems and challenges of the MECDES from the perspectives of the characterization of the energetic mass-energy potential,the synergistic transformation and energy-potential coupling mechanism of multi-energy complementation,energy quality improvement and storage,and proactive regulation of the MECDES.Furthermore,the latest research progress of the MECDES for trickling the key scientific issues is comprehensively presented by proposing the distributed energy system with the complementation of multi-energy sources,developing novel ways of the energy potential coupling and energy cascaded comprehensive utilization of multi-energy complementation,proposing a new theory of multi-energy complementation and energy potential coupling and a new mechanism of source complementation,processing matching and thermodynamic cycle system collaborative conversion of both the fossil energy and renewable energy,and developing a new method of proactive adjust and control for adapting to fluctuating energy input and various energy load demands.Finally,the prospects and recommendations for the future research and development direction of MECDES are provided.
基金supported by the National Key R&D Program of China(No.2021ZD0112700).
文摘This paper develops an advanced framework for the operational optimization of integrated multi-energy systems that encompass electricity,gas,and heating networks.Introducing a cutting-edge stochastic gradient-enhanced distributionally robust optimization approach,this study integrates deep learning models,especially generative adversarial networks,to adeptly handle the inherent variability and uncertainties of renewable energy and fluctuating consumer demands.The effectiveness of this framework is rigorously tested through detailed simulations mirroring real-world urban energy consumption,renewable energy production,and market price fluctuations over an annual period.The results reveal substantial improvements in the resilience and efficiency of the grid,achieving a reduction in power distribution losses by 15%and enhancing voltage stability by 20%,markedly outperforming conventional systems.Additionally,the framework facilitates up to 25%in cost reductions during peak demand periods,significantly lowering operational costs.The adoption of stochastic gradients further refines the framework’s ability to continually adjust to real-time changes in environmental and market conditions,ensuring stable grid operations and fostering active consumer engagement in demand-side management.This strategy not only aligns with contem-porary sustainable energy practices but also provides scalable and robust solutions to pressing challenges in modern power network management.
基金supported by the National Natural Science Foundation of China(No.52205468,No.52275431,No.52375186)China Postdoctoral Science Foundation(No.2025M771349)Zhejiang Province Natural Science Foundation(No.LD22E050001)。
文摘The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency,making it imperative to address the challenge of efficiently and accurately machining film cooling holes.It has been demonstrated that conventional long-pulse lasers are incapable of meeting the elevated quality surface finish requirements for these holes,a consequence of the severe thermal defects.The employment of backside water-assisted laser drilling technology confers a number of distinct advantages in terms of mitigating laser thermal damage,thus representing a highly promising solution to this challenge.However,significant accumulation of bubbles and machining products during the backside water-assisted laser drilling process has been demonstrated to have a detrimental effect on laser transmission and machining stability,thereby reducing machining quality.In order to surmount these challenges,a novel method has been proposed,namely an ultrasonic shock water flow-assisted picosecond laser drilling technique.Numerical models for ultrasonic acoustic streaming and particle tracking for machining product transport have been established to investigate the mechanism.The simulation results demonstrated that the majority of the machining products could rapidly move away from the machining area because of the action of acoustic streaming,thereby avoiding the accumulation of bubbles and products.Subsequent analysis,comparing the process performance in micro-hole machining,confirmed that the ultrasonic field could effectively eliminate bubble and chip accumulation,thus significantly improving micro-hole quality.Furthermore,the impact of ultrasonic and laser parameters on micro-hole quality under varying machining methods was thoroughly investigated.The findings demonstrated that the novel methodology outlined in this study yielded superior-quality micro-holes at elevated ultrasonic and laser power levels,in conjunction with reduced laser frequency and scanning velocity.The taper of the micro-holes produced by the new method was reduced by more than 25%compared with the other conventional methods.
文摘With the rapid growth of photovoltaic integration,the volatility and uncertainty of intermittent photovoltaic injection will dramatically reduce system operation reliability from the generation side.The system operator may face certain financial risks brought by unexpected power failure under low operation reliability.Therefore,maintaining sufficient power reserve to meet system operation reliability and reduce risk,especially in an isolated system,is essential.However,the traditional reserve preparation strategy fails to consider the uncertainties of the power generation under the high penetration levels of emerging renewable energy resources.A novel reserve preparation strategy for an isolated system is developed in this paper using a twostage model.In the first stage,the optimal hourly scheduling of an isolated system is determined.In the second stage,a minute level conditional value-at-risk(CVaR)based model is established where the uncertainty of the reserve requirement is introduced with the chance constraint.The proposed discretized step transformation(DST)and subtraction type convolution(STC)methods are utilized to convert the model into mixedinteger linear programming,and finally solved by applying the CPLEX solver.The IEEE 39-bus system is used as the test case to validate the feasibility and effectiveness of the proposed two-stage model.
基金supported by the second batch of the soft subject research project of China Southern Power Grid Corporation in 2022,‘Exploring the construction path of multi energy complementary ecosystem of industrial parks in Qianhai’(XNXM_20221209003).
文摘The multi-energy complementary ecosystem is an important form of the modern energy system.However,standardized evaluation criteria and the corresponding method framework have not yet been formed,resulting in unclear standards and irregular processes of its construction.To cope with this issue,a novel comprehensive evaluation framework for multi-energy complementary ecosystems is proposed in this study.First,a 5D comprehensive evaluation criteria system,including environment,economy,technology,safety and systematicness,is constructed.Then,a novel multicriteria decision-making model integrating an analytic network process,entropy and preference-ranking organization method for enrichment evaluation under an intuitional fuzzy environment is proposed.Finally,four practical cases are used for model testing and empirical analysis.The results of the research show that the unit cost of the energy supply and the internal rate of return indexes have the highest weights of 0.142 and 0.010,respectively.It means that they are the focus in the construction of a multi-energy complementary ecosystem.The net flows of four cases are 0.015,0.123,-0.132 and-0.005,indicating that cases with a variety of energy supply forms and using intelligent management and control platforms to achieve cold,heat and electrical coupling have more advantages.
文摘Under the current long-term electricity market mechanism,new energy and thermal power face issues such as deviation assessment and compression of generation space.The profitability of market players is limited.Simultaneously,the cooperation model among various energy sources will have a direct impact on the alliance’s revenue and the equity of income distribution within the alliance.Therefore,integrating new energy with thermal power units into an integrated multi-energy complementary system to participate in the long-term electricity market holds significant potential.To simulate and evaluate the benefits and internal distribution methods of a multi-energy complementary system participating in long-term market transactions,this paper first constructs a multi-energy complementary system integrated with new energy and thermal power generation units at the same connection point,and participates in the annual bilateral game as a unified market entity to obtain the revenue value under the annual bilateral market.Secondly,based on the entropy weight method,improvements are made to the traditional Shapley value distribution model,and an internal distribution model for multi-energy complementary systems with multiple participants is constructed.Finally,a Markov Decision Process(MDP)evaluation system is constructed for practical case verification.The research results show that the improved Shapley value distribution model achieves higher satisfaction,providing a reasonable allocation scheme for multi-energy complementary cooperation models.
基金supported by the Science and Technology Project of State Grid Corporation of China.
文摘In the background of the large-scale development and utilization of renewable energy,the joint operation of a variety of heterogeneous energy sources has become an inevitable development trend.However,the physical characteristics of different power sources and the inherent uncertainties of renewable energy power generation have brought difficulties to the planning,operation and control of power systems.For now,the utilization of multi-energy complementarity to promote energy transformation and improve the consumption of renewable energy has become a common understanding among researchers and the engineering community.This paper makes a review of the research on complementarity of new energy high proportion multi-energy systems from uncertainty modeling,complementary characteristics,planning and operation.We summarize the characteristics of the existing research and provide a reference for the further work.
基金supported in part by the National Natural Science Foundation of China(52107076)in part by the Natural Science Foundation of Jiangsu Province(BK20200013)in part by the Smart Grid Joint Fund of National Science Foundation of China&State Grid Corporation of China(U1866208).
文摘With increasing interdependence among electricity,district heating,and natural gas systems in economy and physics,this paper focuses on the optimal bidding problem of a dominant gas-fired CHP unit in synchronized electricity-heat-gas markets with real-life step-wise energy offer format.Gas-fired CHP generators act as price makers and submit price-quantity offering curves in independently cleared electricity and district heating markets.A novel loss-embedded power flow model is proposed for market clearing which accounts for active power loss,congestion,reactive power flow,and voltage constraints.Adding penalty terms into the objective function eliminates additional binary variables,which eases computation burden.A two-stage trading mechanism is designed for gas-fired CHP generators to simultaneously participate in the multi-energy market.Based on a mathematical program with equilibrium constraints,an optimal bidding model is established in which the bilinear terms are eliminated by applying the binary expansion method.A diagonalization algorithm can be nested in the proposed trading mechanism if we intend to study the Nash equilibrium of the Nperson Cournot oligopoly market.Numerical tests with different scales are carried out to validate the proposed methodology in detail.
基金supported by Zhejiang Provincial Natural Science Foundation of China(No.LZ24E020001).
文摘Complementary inverter is the basic unit for logic circuits,but the inverters based on full oxide thin-film transistors(TFTs)are still very limited.The next challenge is to realize complementary inverters using homogeneous oxide semiconduc-tors.Herein,we propose the design of complementary inverter based on full ZnO TFTs.Li-N dual-doped ZnO(ZnO:(Li,N))acts as the p-type channel and Al-doped ZnO(ZnO:Al)serves as the n-type channel for fabrication of TFTs,and then the complemen-tary inverter is produced with p-and n-type ZnO TFTs.The homogeneous ZnO-based complementary inverter has typical volt-age transfer characteristics with the voltage gain of 13.34 at the supply voltage of 40 V.This work may open the door for the development of oxide complementary inverters for logic circuits.
文摘Gait,the unique pattern of how a person walks,has emerged as one of the most promising biometric features in modern intelligent sensing.Unlike fingerprints or facial characteristics,gait can be captured unobtrusively and at a distance,without requiring the subject’s awareness or cooperation.This makes it highly suitable for long-range surveillance,forensic investigation,and smart environments where contactless recognition is crucial.Traditional gait-recognition systems rely either on silhouettes,which capture the outer appearance of a person,or on skeletons,which describe the internal structure of human motion.Each modality provides only a partial understanding of gait.Silhouettes emphasize shape and contour but are easily distorted by clothing or carried objects;skeletons describe motion dynamics and limb coordination but lose discriminative details about body shape.This article presents the concept of Complementary Semantic Embedding(CSE),a unified framework that merges silhouette and skeleton information into a comprehensive semantic representation of human walking.By modeling the complementary nature of appearance and structure,the approach achieves more robust and accurate gait recognition even under challenging conditions.
基金financial support from the National Natural Science Foundation of China(NSFC 22172082)the Fundamental Research Funds for the Central Universities。
文摘Mild electrocatalytic nitrate reduction reaction(NO_(3)RR),driven by renewable electricity,is regarded as a desirable strategy for green ammonia synthesis and simultaneous removal of nitrogen-containing environmental pollutants.In view of different supply voltages from renewable energy sources,developing costeffective and efficient electrocatalysts with a wide operating potential window is very meaningful for practical application.However,currently reported catalysts usually need to introduce noble metals to synergistically achieve wide-potential selective ammonia synthesis from nitrate.In this work,we present for the first time a dual-transition-metal electrocatalyst(Fe_(3)C-CuO_(x)@NC,x=0,1)with wide-potential-adaptability for highly selective nitrate reduction to ammonia.Such Fe_(3)C-CuO_(x)@NC with spatially separated CuO_(x)and noblemetal-like Fe_(3)C nanoparticles encapsulated with nitrogen-doped graphitized carbon,exhibits outstanding performance in NO_(3)RR with desirable NH_(3)Faraday efficiency of more than 90%over a wide potential ranging from-0.2 V vs.RHE to-0.6 V vs.RHE,comparable to the reported noble metal catalysts.Different from common tandem catalysis,the wide-potential high ammonia selectivity of Fe_(3)C-CuO_(x)@NC is domina ntly ascribed to the complementary enhancement between CuO_(x)and Fe_(3)C,fully supported by results of experiments and density function theory calculations.CuO_(x)exhibit highly intrinsic nitrate reduction to nitrite to compensate for the slow potential determination step(^(*)NO_(3)→^(*)NO_(3)H)of Fe_(3)C,while Fe_(3)C,besides behaving like noble metals to supply adequate active hydrogens,has both good adsorption and reduction abilities for nitrite species to ammonia.Moreover,Fe_(3)C partially stabilizes active Cu^(0)/Cu^(+)sites,and the unique carbon-layer enca psulation structure effectively prevents the agglomeration and corrosion of metal nanoparticles during the electrocatalysis,thus maintaining good cyclic stability.The Zn-NO_(3)^(-)battery assembled with Fe_(3)C-CuO_(x)@NC can reach a high power density of 5.2 mW cm^(-2)at a potential of 1.0 V vs.Zn,with an NH_(3)Faraday efficiency of 92.4%at a current of 8.0 mA,proving its potential practical application.This advance provides unique insights into complementary catalysis mechanisms on multiple metal sites in NO_(3)RR,and offers a reference for the design of other transition metal electrocatalysts matching with renewable electricity.
文摘Background:The use of complementary and alternative medicine(CAM)is common among individuals with underlying chronic illnesses.Objective:This systematic review and meta-analysis investigated the global prevalence and patterns of CAM use among individuals with chronic kidney disease(CKD).Search strategy:PubMed,Embase,and Cumulative Index to Nursing and Allied Health Literature Plus were searched from inception until 26th February 2024.Inclusion criteria:Original articles reporting the use of at least one type of CAM among individuals aged above 18 years old and at all stages of CKD or undergoing any form of kidney replacement therapy.Data extraction and analysis:Two independent reviewers performed the literature screening.The data were extracted from the included studies by one reviewer and cross-checked by another.Discrepancies were resolved by discussion and consensus among two reviewers.Primary information included prevalence of CAM use,types of CAM used,reasons for CAM use,factors associated with CAM use,and disclosure to healthcare providers.Meta-analyses were performed to determine the pooled prevalence of CAM use and non-disclosure of CAM using a random effect model.Results:Forty-one studies were included in this systematic review and meta-analysis.The pooled prevalence of CAM use was 43%(95%confidence interval:34%,51%),I2=99.46%.The reasons for CAM use included treatment of underlying comorbidities,complications or symptoms,maintenance of general health,and treatment of CKD.Nutritional approaches were the most common CAM modality,with 412different herbal and dietary supplements reported;psychological and physical approaches included massage therapy,relaxation techniques,and mind–body practices;and other complementary health approaches such as homeopathy,traditional Chinese medicine,and Ayurvedic medicine were also frequently reported.Factors associated with CAM use included sociodemographic characteristics such as older age,female gender,or higher income;disease or therapy factors such as not having diabetes,relying on hemodialysis,or poor adherence to medication;and patient or internal factors such as positive attitude towards CAM and perceived safety of CAM.About 66%(61%,72%)of CAM users did not disclose the use of CAM to their healthcare providers.Conclusion:CAM use is prevalent among individuals with CKD,and healthcare providers should communicate openly and effectively to emphasize the rational use of CAM to avoid potential harm.
基金supported by the National Natural Science Foundation of China(62001481,61890542)the Natural Science Foundation of Hunan Province(2021JJ40686).
文摘Low sidelobe waveform can reduce mutual masking between targets and increase the detection probability of weak targets.A low sidelobe waveform design method based on complementary amplitude coding(CAC)is proposed in this paper,which can be used to reduce the sidelobe level of multiple waveforms.First,the CAC model is constructed.Then,the waveform design problem is transformed into a nonlinear optimization problem by constructing an objective function using the two indicators of peak-to-sidelobe ratio(PSLR)and integrated sidelobe ratio(ISLR).Finally,genetic algorithm(GA)is used to solve the optimization problem to get the best CAC waveforms.Simulations and experiments are conducted to verify the effectiveness of the proposed method.
文摘This editorial is based on the network pharmacology and in vivo study by Qin et al,which investigated the potential therapeutic mechanisms of Panax ginseng(P.ginseng)in ulcerative colitis.The key findings from the study included the identification of the targets of P.ginseng and ulcerative colitis,elucidation of mechanistic pathways,and in vivo validation of the pharmacological activity and therapeutic effect of panaxadiol,a key active component of P.ginseng.This editorial provides additional context regarding the evidence supporting the use of ginseng and other commonly used complementary therapies that clinicians may encounter.We also aim to highlight potential similarities between the mechanisms of popular complementary and conventional medical therapies.
基金Supported by the Coordination of Improvement of Higher Education Personnel(CAPES)and National Council for Scientific and Technological Development(CNPq),No.311427/2023-5.
文摘The international scientific literature presents still incipient results regarding the management of cancer symptom clusters by oncology nursing,especially in pediatric oncology.This is a promising field of investigation for clinical nurses and researchers,and when it is subsidized by medium-range theories,they co-rroborate the diagnoses and interventions of nursing in oncology,enhancing the science of nursing care.This minireview article aims to discuss the utilizing the hospital clowns as a complementary therapy,to enhance quality of life and reduce stress and fatigue in pediatric cancer patients.Overall,the evidence presented so far pointed out that complementary therapy might help improve the quality of life of pediatric cancer patients,and that complementary therapy usage should be part of a health comprehensive care model,delivering therapeutic approaches that might enhance the mind-body during a pediatric cancer patients’life span.The results of scientific investigations by nurses,particularly those linked to the basic sciences,play a critical role in advancing personalized care in pediatric integrative oncology.
