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Determining Optimal Strategies to Reduce Maternal and Child Mortality in Rural Areas in Western China: an Assessment Using the Lives Saved Tool
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作者 JIANG Zhen GUO Sufang +3 位作者 Robert W.SCHERPBIER WEN Chun Mei XU Xiao Chao GUO Yan 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第8期606-610,共5页
China, as a whole, is about to meet the Millennium Development Goals for reducing the maternal mortality ratio (MMR) and infant mortality rate (IMR), but the disparities between rural area and urban area still exists.... China, as a whole, is about to meet the Millennium Development Goals for reducing the maternal mortality ratio (MMR) and infant mortality rate (IMR), but the disparities between rural area and urban area still exists. This study estimated the potential effectiveness of expanding coverage with high impact interventions using the Lives Saved Tool (LiST). It was found that gestational hypertension, antepartum and postpartum hemorrhage, preterm birth, neonatal asphyxia, and neonatal childhood pneumonia and diarrhea are still the major killers of mothers and children in rural area in China. It was estimated that 30% of deaths among 0-59 month old children and 25% of maternal deaths in 2008 could be prevented in 2015 if primary health care intervention coverage expanded to a feasible level. The LiST death cause framework, compared to data from the Maternal and Child Mortality Surveillance System, represents 60%-80% of neonatal deaths, 40%-50% of deaths in 1-59 month old children and 40%-60% of maternal deaths in rural areas of western China. 展开更多
关键词 rate Li an Assessment Using the Lives Saved Tool Determining optimal strategies to Reduce Maternal and Child Mortality in Rural Areas in Western China
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Optimal strategies of groundwater development in the Pingtung Plain,Taiwan
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《Global Geology》 1998年第1期103-104,共2页
关键词 optimal strategies of groundwater development in the Pingtung Plain Taiwan
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Optimal Strategies Trajectory with Multi-Local-Worlds Graph
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作者 Xiang Yu Chonghua Wang +2 位作者 Xiaojing Zheng Chaoyu Zeng Brij BGupta 《Computers, Materials & Continua》 SCIE EI 2023年第4期2079-2099,共21页
This paper constructs a non-cooperative/cooperative stochasticdifferential game model to prove that the optimal strategies trajectory ofagents in a system with a topological configuration of a Multi-Local-Worldgraph w... This paper constructs a non-cooperative/cooperative stochasticdifferential game model to prove that the optimal strategies trajectory ofagents in a system with a topological configuration of a Multi-Local-Worldgraph would converge into a certain attractor if the system’s configuration isfixed. Due to the economics and management property, almost all systems aredivided into several independent Local-Worlds, and the interaction betweenagents in the system is more complex. The interaction between agents inthe same Local-World is defined as a stochastic differential cooperativegame;conversely, the interaction between agents in different Local-Worldsis defined as a stochastic differential non-cooperative game. We construct anon-cooperative/cooperative stochastic differential game model to describethe interaction between agents. The solutions of the cooperative and noncooperativegames are obtained by invoking corresponding theories, and thena nonlinear operator is constructed to couple these two solutions together.At last, the optimal strategies trajectory of agents in the system is proven toconverge into a certain attractor, which means that strategies trajectory arecertainty as time tends to infinity or a large positive integer. It is concluded thatthe optimal strategy trajectory with a nonlinear operator of cooperative/noncooperativestochastic differential game between agents can make agentsin a certain Local-World coordinate and make the Local-World paymentmaximize, and can make the all Local-Worlds equilibrated;furthermore, theoptimal strategy of the coupled game can converge into a particular attractorthat decides the optimal property. 展开更多
关键词 Multi-Local-world graph stochastic differential game optimal strategy ATTRACTOR
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Reinforcement Learning Based Quantization Strategy Optimal Assignment Algorithm for Mixed Precision
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作者 Yuejiao Wang Zhong Ma +2 位作者 Chaojie Yang Yu Yang Lu Wei 《Computers, Materials & Continua》 SCIE EI 2024年第4期819-836,共18页
The quantization algorithm compresses the original network by reducing the numerical bit width of the model,which improves the computation speed. Because different layers have different redundancy and sensitivity to d... The quantization algorithm compresses the original network by reducing the numerical bit width of the model,which improves the computation speed. Because different layers have different redundancy and sensitivity to databit width. Reducing the data bit width will result in a loss of accuracy. Therefore, it is difficult to determinethe optimal bit width for different parts of the network with guaranteed accuracy. Mixed precision quantizationcan effectively reduce the amount of computation while keeping the model accuracy basically unchanged. In thispaper, a hardware-aware mixed precision quantization strategy optimal assignment algorithm adapted to low bitwidth is proposed, and reinforcement learning is used to automatically predict the mixed precision that meets theconstraints of hardware resources. In the state-space design, the standard deviation of weights is used to measurethe distribution difference of data, the execution speed feedback of simulated neural network accelerator inferenceis used as the environment to limit the action space of the agent, and the accuracy of the quantization model afterretraining is used as the reward function to guide the agent to carry out deep reinforcement learning training. Theexperimental results show that the proposed method obtains a suitable model layer-by-layer quantization strategyunder the condition that the computational resources are satisfied, and themodel accuracy is effectively improved.The proposed method has strong intelligence and certain universality and has strong application potential in thefield of mixed precision quantization and embedded neural network model deployment. 展开更多
关键词 Mixed precision quantization quantization strategy optimal assignment reinforcement learning neural network model deployment
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Optimization Strategies of Beijing Elderly Care Service Stations Based on Questionnaire Survey Method: A Case Study of Zhanlan Road Street of Xicheng District
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作者 YUAN Shuai PENG Li +2 位作者 WANG Zhihao REN Pengyu DING Yuqi 《Journal of Landscape Research》 2024年第3期15-20,26,共7页
4 elderly care service stations in Zhanlan Road Street,Xicheng District,Beijing are selected,and questionnaires are designed and distributed to the surrounding elderly population to understand their needs and satisfac... 4 elderly care service stations in Zhanlan Road Street,Xicheng District,Beijing are selected,and questionnaires are designed and distributed to the surrounding elderly population to understand their needs and satisfaction with the station environment.By observing elderly care service stations on site,the characteristics,obstacles,and shortcomings of the environment are recorded,and relevant data are collected and analyzed,such as the characteristics of the elderly population being interviewed,the planning and design data of the station environment,and the distribution of service facilities.The overall characteristics of the spatial environment of elderly care stations are summarized,and renovation measures and optimization suggestions are provided for the current shortcomings,thereby providing some basis for the spatial design of community elderly care service stations in the future. 展开更多
关键词 Old people Community elderly care service station Space renovation Optimization strategy
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Research Status,Practical Dilemmas,and Optimization Strategies of Blended Teaching in Universities
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作者 Zhiying Zhu Yinxia Wei 《Journal of Contemporary Educational Research》 2024年第7期210-215,共6页
Blended teaching has emerged as a prominent subject in the recent reform and innovation of higher education.It has become imperative and guiding for colleges and universities to embrace a mixed teaching approach that ... Blended teaching has emerged as a prominent subject in the recent reform and innovation of higher education.It has become imperative and guiding for colleges and universities to embrace a mixed teaching approach that aligns with the evolving needs of education and teaching in the new era.This paper aims to provide a comprehensive overview of the research status surrounding blended teaching,encompassing fundamental issues,teaching design,practical guidance,teaching effectiveness,and evaluation.By critically examining the current challenges associated with blended teaching,this study proposes optimization strategies including enhancing student participation and interaction,promoting deep learning,improving teachers’preparedness,teaching technologies,and curriculum design capabilities,strengthening top-level design,and perfecting evaluation and incentive mechanisms.These strategies provide new directions for the reform of blended teaching. 展开更多
关键词 Blended teaching Research status Practical dilemma Optimization strategy
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A Study on the Educational Mode and Optimization Strategies of“Micro Ideological and Political Education”
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作者 Tingting Zhang Chunhong Yu 《Journal of Contemporary Educational Research》 2024年第11期179-186,共8页
The model of“micro ideological and political education”is adapted to the characteristics of the new era and the real needs of ideological and political education in colleges and universities.Based on the work of“mi... The model of“micro ideological and political education”is adapted to the characteristics of the new era and the real needs of ideological and political education in colleges and universities.Based on the work of“micro ideological and political education”in colleges and universities under the development of all-media integration,this study summarizes the main practices,achievements,and problems of“micro ideological and political education”in colleges and universities,and proposes to optimize and improve the work of“micro ideological and political education”from the perspectives of platform construction,work creation,team building,and guarantee mechanism.Optimization and enhancement are needed to effectively improve the relevance and effectiveness of“micro ideological and political education”work. 展开更多
关键词 Micro ideological and political education New media era Optimization strategy
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Bi-matrix Games with Fuzzy Strategies and Fuzzy Payoffs and Their Mathematical Programming Equivalents
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作者 高璟 张强 《Journal of Beijing Institute of Technology》 EI CAS 2009年第3期370-374,共5页
A fuzzy bi-matrix game(FBG),namely a two-person non-zero-sum game with fuzzy strategies and fuzzy payoffs is proposed.We have defined and analyzed the optimal strategies of this FBG,and shown that it can be transfor... A fuzzy bi-matrix game(FBG),namely a two-person non-zero-sum game with fuzzy strategies and fuzzy payoffs is proposed.We have defined and analyzed the optimal strategies of this FBG,and shown that it can be transformed into a corresponding fuzzy mathematical programming issue,for which a ranking function approach can be applied.In addition,optimal strategies of FBG for both Player I and Player II can be gotten. 展开更多
关键词 fuzzy bi-matrix game equilibrium solution optimal strategies mathematical programming
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Modeling the dynamic optimal advertising in stochastic condition
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作者 RongDU QiyingHU ZhiqingMENG 《控制理论与应用(英文版)》 EI 2004年第1期102-104,共3页
An effort to model the dynamic optimal advertising was made with the uncertainty of sales responses in consideration. The problem of dynamic advertising was depicted as a Markov decision process with two state variabl... An effort to model the dynamic optimal advertising was made with the uncertainty of sales responses in consideration. The problem of dynamic advertising was depicted as a Markov decision process with two state variables. When a firm launches an advertising campaign, it may predict the probability that the campaign will obtain the sales réponse. This probability was chosen as one state variable. Cumulative sales volume was chosen as another state variable which varies randomly with advertising. The only decision variable was advertising expenditure. With these variables, a multi-stage Markov decision process model was formulat ed. On the basis of some propositions the model was analyzed. Some analytical results about the optimal strategy have been derived, and their practical implications have been explained. 展开更多
关键词 Stochastic optimal model ADVERTISING Markov decision process optimal strategies
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A DIRECT METHOD IN OPTIMAL PORTFOLIO AND CONSUMPTION CHOICE 被引量:9
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作者 WU ZHEN AND XU WENSHENG (Department of Mathematics,Shandong University, Jinan 250100.)(Department of Applied Mathematics, Zhejiang University,Hangzhou 310027.) 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 1996年第3期349-354,共6页
In this paper we use a direct method to solve the optimal portfolio andconsumption choice problem in the security market for a specific case,in which theutility function is of a given homogenous form, i.e. the so-call... In this paper we use a direct method to solve the optimal portfolio andconsumption choice problem in the security market for a specific case,in which theutility function is of a given homogenous form, i.e. the so-called CRRA case. The ideacomes from the completion technique ever used in LQ optimal control. 展开更多
关键词 optimal strategy PORTFOLIO CONSUMPTION security market.
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Optimal livelihood strategy for different poverty groups among farmers: a case study of the Qin-Ba Mountain area in South-Shaanxi, China 被引量:6
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作者 SU Fang YIN Ya-juan 《Journal of Mountain Science》 SCIE CSCD 2020年第5期1206-1220,共15页
Achieving sustainable livelihood is the ultimate goal of poverty alleviation efforts in mountainous areas,and selecting an optimal livelihood strategy for different poverty-type farmers greatly improves farmers’livel... Achieving sustainable livelihood is the ultimate goal of poverty alleviation efforts in mountainous areas,and selecting an optimal livelihood strategy for different poverty-type farmers greatly improves farmers’livelihood capital,resists livelihood risks,and promotes sustainable development.For farmers,optimal livelihood strategy means better employment opportunities,higher family income(or better income structure),and stronger employability or development potential.This paper classifies different types of farmers’poverty on the basis of a quantitative evaluation of farmers’livelihood capital in the Qin-ba Mountain Area in South-Shaanxi by using the k-means clustering method and subsequently the fuzzy evaluation method to evaluate the effectiveness of farmers’livelihood strategies.Then,the multi-attribute decision-making model is used to analyze the selection of optimal livelihood strategies for different poverty-type farmers.The results suggest a significant difference in the selection of the optimal livelihood strategy for different poverty-type farmers.Farmers without financial and human capital choose to"go out to work,"farmers lacking natural capital choose to"acquire social insurance and government relief,"farmers without physical capital choose to"use loans,"and farmers lacking social capital choose to"use savings."Studying the selection of optimal livelihood strategies for different poverty-type farmers can help to propose targeted sustainable livelihood optimization programs for farmers and accelerate efforts to overcome poverty in mountainous areas. 展开更多
关键词 optimal strategy Livelihood capital Effectiveness evaluation Qin-Ba Mountain Area SHAANXI
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An Optimal Control Strategy for Multi-UAVs Target Tracking and Cooperative Competition 被引量:8
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作者 Yiguo Yang Liefa Liao +1 位作者 Hong Yang Shuai Li 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2021年第12期1931-1947,共17页
An optimal control strategy of winner-take-all(WTA)model is proposed for target tracking and cooperative competition of multi-UAVs(unmanned aerial vehicles).In this model,firstly,based on the artificial potential fiel... An optimal control strategy of winner-take-all(WTA)model is proposed for target tracking and cooperative competition of multi-UAVs(unmanned aerial vehicles).In this model,firstly,based on the artificial potential field method,the artificial potential field function is improved and the fuzzy control decision is designed to realize the trajectory tracking of dynamic targets.Secondly,according to the finite-time convergence high-order differentiator,a double closed-loop UAV speed tracking the controller is designed to realize the speed control and tracking of the target tracking trajectory.Numerical simulation results show that the designed speed tracking controller has the advantages of fast tracking,high precision,strong stability and avoiding chattering.Finally,a cooperative competition scheme of multiple UAVs based on WTA is designed to find the minimum control energy from multiple UAVs and realize the optimal control strategy.Theoretical analysis and numerical simulation results show that the model has the fast convergence,high control accuracy,strong stability and good robustness. 展开更多
关键词 Artificial potential field(APF) fuzzy control higher-order differentiator optimal control strategy winner-take-all(WTA)
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Fundamental Understanding and Optimization Strategies for Dual‑Ion Batteries:A Review 被引量:5
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作者 Chong Chen Chun‑Sing Lee Yongbing Tang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第8期205-224,共20页
There has been increasing demand for high-energy density and longcycle life rechargeable batteries to satisfy the ever-growing requirements for nextgeneration energy storage systems.Among all available candidates,dual... There has been increasing demand for high-energy density and longcycle life rechargeable batteries to satisfy the ever-growing requirements for nextgeneration energy storage systems.Among all available candidates,dual-ion batteries(DIBs)have drawn tremendous attention in the past few years from both academic and industrial battery communities because of their fascinating advantages of high working voltage,excellent safety,and environmental friendliness.However,the dynamic imbalance between the electrodes and the mismatch of traditional electrolyte systems remain elusive.To fully employ the advantages of DIBs,the overall optimization of anode materials,cathode materials,and compatible electrolyte systems is urgently needed.Here,we review the development history and the reaction mechanisms involved in DIBs.Afterward,the optimization strategies toward DIB materials and electrolytes are highlighted.In addition,their energy-related applications are also provided.Lastly,the research challenges and possible development directions of DIBs are outlined. 展开更多
关键词 Dual-ion batteries Reaction mechanisms Optimization strategies Energy storage
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Recent Advances on Challenges and Strategies of Manganese Dioxide Cathodes for Aqueous Zinc-Ion Batteries 被引量:5
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作者 Yuhui Xu Gaini Zhang +9 位作者 Jingqian Liu Jianhua Zhang Xiaoxue Wang Xiaohua Pu Jingjing Wang Cheng Yan Yanyan Cao Huijuan Yang Wenbin Li Xifei Li 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第6期158-181,共24页
Aqueous zinc-ion batteries(AZIBs)are regarded as promising electrochemical energy storage devices owing to its low cost,intrinsic safety,abundant zinc reserves,and ideal specific capacity.Compared with other cathode m... Aqueous zinc-ion batteries(AZIBs)are regarded as promising electrochemical energy storage devices owing to its low cost,intrinsic safety,abundant zinc reserves,and ideal specific capacity.Compared with other cathode materials,manganese dioxide with high voltage,environmental protection,and high theoretical specific capacity receives considerable attention.However,the problems of structural instability,manganese dissolution,and poor electrical conductivity make the exploration of high-performance manganese dioxide still a great challenge and impede its practical applications.Besides,zinc storage mechanisms involved are complex and somewhat controversial.To address these issues,tremendous efforts,such as surface engineering,heteroatoms doping,defect engineering,electrolyte modification,and some advanced characterization technologies,have been devoted to improving its electrochemical performance and illustrating zinc storage mechanism.In this review,we particularly focus on the classification of manganese dioxide based on crystal structures,zinc ions storage mechanisms,the existing challenges,and corresponding optimization strategies as well as structure-performance relationship.In the final section,the application perspectives of manganese oxide cathode materials in AZIBs are prospected. 展开更多
关键词 aqueous zinc-ion batteries CHALLENGES manganese dioxide optimized strategies zinc storage mechanisms
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Optimization Strategies Toward Functional Sodium-Ion Batteries 被引量:5
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作者 Jingwei Chen Gupta Adit +3 位作者 Lun Li Yingxin Zhang Daniel H.C.Chua Pooi See Lee 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第4期332-354,共23页
Exploration of alternative energy storage systems has been more than necessary in view of the supply risks haunting lithium-ion batteries.Among various alternative electrochemical energy storage devices,sodium-ion bat... Exploration of alternative energy storage systems has been more than necessary in view of the supply risks haunting lithium-ion batteries.Among various alternative electrochemical energy storage devices,sodium-ion battery outstands with advantages of cost-effectiveness and comparable energy density with lithium-ion batteries.Thanks to the similar electrochemical mechanism,the research and development of lithium-ion batteries have forged a solid foundation for sodium-ion battery explorations.Advancements in sodium-ion batteries have been witnessed in terms of superior electrochemical performance and broader application scenarios.Here,the strategies adopted to optimize the battery components(cathode,anode,electrolyte,separator,binder,current collector,etc.)and the cost,safety,and commercialization issues in sodium-ion batteries are summarized and discussed.Based on these optimization strategies,assembly of functional(flexible,stretchable,self-healable,and self-chargeable)and integrated sodium-ion batteries(−actuators,−sensors,electrochromic,etc.)have been realized.Despite these achievements,challenges including energy density,scalability,trade-off between energy density and functionality,cost,etc.are to be addressed for sodium-ion battery commercialization.This review aims at providing an overview of the up-to-date achievements in sodium-ion batteries and serves to inspire more efforts in designing upgraded sodium-ion batteries. 展开更多
关键词 energy storage integration MULTIFUNCTIONAL optimization strategies sodiumion batteries
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Understanding of the charge storage mechanism of MnO_(2)-based aqueous zinc-ion batteries:Reaction processes and regulation strategies 被引量:4
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作者 Nan Zhang Yu-Rui Ji +3 位作者 Jian-Cang Wang Peng-Fei Wang Yan-Rong Zhu Ting-Feng Yi 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期423-463,I0010,共42页
Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of mo... Though secondary aqueous Zn ion batteries(AZIBs)have been received broad concern in recent years,the development of suitable cathode materials of AZIBs is still a big challenge.The MnO_(2) has been deemed as one of most hopeful cathode materials of AZIBs on account of some extraordinary merits,such as richly natural resources,low toxicity,high discharge potential,and large theoretical capacity.However,the crystal structure diversity of MnO_(2) results in an obvious various of charge storage mechanisms,which can cause great differences in electrochemical performance.Furthermore,several challenges,including intrinsic poor conductivity,dissolution of manganese and sluggish ion transport dynamics should be conquered before real practice.This work focuses on the reaction mechanisms and recent progress of MnO_(2)-based materials of AZIBs.In this review,a detailed review of the reaction mechanisms and optimal ways for enhancing electrochemical performance for MnO_(2)-based materials is proposed.At last,a number of viewpoints on challenges,future development direction,and foreground of MnO_(2)-based materials of aqueous zinc ions batteries are put forward.This review clarifies reaction mechanism of MnO_(2)-based materials of AZIBs,and offers a new perspective for the future invention in MnO_(2)-based cathode materials,thus accelerate the extensive development and commercialization practice of aqueous zinc ions batteries. 展开更多
关键词 Aqueous zinc-ion battery MnO_(2) Charge storage mechanism Optimization strategy
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Recent progress and strategies toward high performance zinc-organic batteries 被引量:4
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作者 Shibing Zheng Qiaoran Wang +2 位作者 Yunpeng Hou Lin Li Zhanliang Tao 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第12期87-112,I0003,共27页
Energy sustainable development has stimulated the pursuit of an eco-friendly energy storage system.Carbon peak and neutrality targets oriented energy storage development will guide the way of further studies on batter... Energy sustainable development has stimulated the pursuit of an eco-friendly energy storage system.Carbon peak and neutrality targets oriented energy storage development will guide the way of further studies on batteries system.However,conventional batteries system(lead-acid batteries,lithium-ion batteries)based on ungreen transition metal oxide,flammable electrolytes or hazardous metals cannot keep pace with the development of society sooner or later.Thus,vast explorations on the advanced rechargeable battery systems were conducted.Compared with other battery systems,zinc ion battery systems with inherent safety,low cost were widely investigated.Especially,the zinc organic batteries based on the eco-efficiency organic cathodes were promising alternative advanced batteries for future energy storage systems.Therefore,various organics and different electrochemistry mechanisms were explored in the zinc batteries system.Herein,a timely review on elaborate analysis about functional groups,fundamentals,progress accompanied by the discussion on the four core issues:voltage,capacity,rate performance,cycle life was presented.Specifically,aiming at these issues,three levels of solution strategies:materials design concepts,morphology structure optimization and electrolyte environment were summarized and proposed for the development and innovation of zinc organic batteries. 展开更多
关键词 Organic materials Zinc batteries Optimization strategies
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Optimal control strategy for energy saving in trains under the four-aspect fixed autoblock system 被引量:3
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作者 Qiheng LU Xiaoyun FENG 《Journal of Modern Transportation》 2011年第2期82-87,共6页
This paper deals with both the leading train and the following train in a train tracking under a four-aspect fixed autoblock system in order to study the optimum operating strategy for energy saving. After analyzing t... This paper deals with both the leading train and the following train in a train tracking under a four-aspect fixed autoblock system in order to study the optimum operating strategy for energy saving. After analyzing the working principle of the four-aspect fixed autoblock system, an energy-saving control model is created based on the dynamics equation of the Wains. In addition to safety, energy consumption and time error are the main concerns of the model. Based on this model, dynamic speed constraints of the following train are proposed, defined by the leading gain dynamically. At the same time, the static speed constraints defined by the line conditions are also taken into account. The parallel genetic algorithm is used to search the optimum operating strategy. In order to simplify the solving process, the external punishment function is adopted to transform this problem with constraints to the one without constraints. By using the real number coding and the strategy of dividing ramps into three parts, the convergence of GA is accelerated and the length of chromosomes is shortened. The simulation result from a four-aspect fixed autoblock system simulation platform shows that the method can reduce the energy consumption effectively in the premise of ensuring safety and punctuality. 展开更多
关键词 leading train following train four-aspect fixed autoblock system optimal control strategy of energysaving train tracking dynamic speed constraints genetic algorithm
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Optimal transmission strategy for spatially correlated MIMO systems with channel statistical information 被引量:1
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作者 ZHAO Zhen-shan XU Guo-zhi 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第4期615-619,共5页
In real multiple-input multiple-output (MIMO) systems, the perfect channel state information (CSI) may be costly or impossible to acquire. But the channel statistical information can be considered relatively stationar... In real multiple-input multiple-output (MIMO) systems, the perfect channel state information (CSI) may be costly or impossible to acquire. But the channel statistical information can be considered relatively stationary during long-term transmission. The statistical information can be obtained at the receiver and fed back to the transmitter and do not require frequent update. By exploiting channel mean and covariance information at the transmitter simultaneously, this paper investigates the optimal trans- mission strategy for spatially correlated MIMO channels. An upper bound of ergodic capacity is derived and taken as the per- formance criterion. Simulation results are also given to show the performance improvement of the optimal transmission strategy. 展开更多
关键词 MIMO optimal transmission strategy Channel statistical information
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Dominating factors on well productivity and development strategies optimization in Weiyuan shale gas play, Sichuan Basin, SW China 被引量:6
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作者 MA Xinhua LI Xizhe +7 位作者 LIANG Feng WAN Yujin SHI Qiang WANG Yonghui ZHANG Xiaowei CHE Mingguang GUO Wei GUO Wei 《Petroleum Exploration and Development》 2020年第3期594-602,共9页
Weiyuan shale gas play is characterized by thin high-quality reservoir thickness,big horizontal stress difference,and big productivity differences between wells.Based on integrated evaluation of shale gas reservoir ge... Weiyuan shale gas play is characterized by thin high-quality reservoir thickness,big horizontal stress difference,and big productivity differences between wells.Based on integrated evaluation of shale gas reservoir geology and well logging interpretation of more than 20 appraisal wells,a correlation was built between the single well test production rate and the high-quality reservoir length drilled in the horizontal wells,high-quality reservoir thickness and the stimulation treatment parameters in over 100 horizontal wells,the dominating factors on horizontal well productivity were found out,and optimized development strategies were proposed.The results show that the deployed reserves of high-quality reservoir are the dominating factors on horizontal well productivity.In other words,the shale gas well productivity is controlled by the thickness of the high-quality reservoir,the high-quality reservoir drilling length and the effectiveness of stimulation.Based on the above understanding,the development strategies in Weiyuan shale gas play are optimized as follows:(1)The target of horizontal wells is located in the middle and lower parts of Longyi 11(Wei202 area)and Longyi 11(Wei204 area).(2)Producing wells are drilled in priority in the surrounding areas of Weiyuan county with thick high-quality reservoir.(3)A medium to high intensity stimulation is adopted.After the implementation of these strategies,both the production rate and the estimated ultimate recovery(EUR)of individual shale gas wells have increased substantially. 展开更多
关键词 Weiyuan shale gas play dominating factors of well productivity deployed reserves of high-quality reservoir thickness of high-quality reservoir high-quality reservoir drilling length effectiveness of stimulation development strategies optimization
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