The environmental challenges from coal mining include coal mine accidents,land subsidence,damage to the water environment,mining waste disposal and air pollution.These are either environmental pollution or landscape c...The environmental challenges from coal mining include coal mine accidents,land subsidence,damage to the water environment,mining waste disposal and air pollution.These are either environmental pollution or landscape change.A conceptual framework for solving mine environmental issues is proposed.Clean processes,or remediation measures,are designed to address environmental pollution.Restoration measures are proposed to handle landscape change.The total methane drainage from 56 Chinese high methane concentration coal mines is about 101.94 million cubic meters.Of this methane,19.32 million,35.58 million and 6.97 million cubic meters are utilized for electricity generation,civil fuel supplies and other industrial purposes,respectively.About 39% of the methane is emitted into the atmosphere.The production of coal mining wastes can be decreased 10% by reuse of mining wastes as underground fills,or by using the waste as fuel for power plants or for raw material to make bricks or other infrastructure materials.The proper use of mined land must be decided in terms of local physical and socio-economical conditions.In European countries more than 50% of previously mined lands are reclaimed as forest or grass lands.However,in China more than 70% of the mined lands are reclaimed for agricultural purposes because the large population and a shortage of farmlands make this necessary.Reconstruction of rural communities or native residential improvement is one environmental problem arising from mining.We suggest two ways to reconstruct a farmer's house in China.展开更多
With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the world.Due to the variable and intermittent nature of wind power production,the system has to frequen...With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the world.Due to the variable and intermittent nature of wind power production,the system has to frequently redispatch generators in order to ensure the effective use of wind power whilst maintaining system security.In this way,traditional generation costs are increased and the social benefit of wind power decreases indirectly.In this paper,a new regulation strategy based on power flow tracing was proposed,taking advantage of a comfort-constrained demand response strategy to follow the fluctuations of wind farm output,with the remaining imbalance of active power compensated by traditional generators.Examples showed that compared with conventional regulation,demand response could reduce the gross operating costs of the system,and the rapid response could help maintaining system stability in case of contingency.The strategy in this paper also applies to other large-scale integration problems associated with renewable energy resources which display short-term production variability.展开更多
There has been much progress in the study of tropical cyclones and tropical meteorology in China in the past few years. A new atmospheric field experiment of tropical cyclone landfall with the acronym of CLATEX (China...There has been much progress in the study of tropical cyclones and tropical meteorology in China in the past few years. A new atmospheric field experiment of tropical cyclone landfall with the acronym of CLATEX (China Landfalling Typhoon Experiment) was implemented in July-August 2002. The boundary layer characteristics of the target typhoon Vongfong and the mesoscale structural features of other land-falling typhoons were studied. In addition, typhoon track operational forecasting errors in the last decade have been reduced because the operational monitoring equipment and forecast techniques were improved. Some results from the research program on tropical cvclone landfall, structure and intensity change, inten-sification near coastal waters, interaction between tropical cyclone and mid-latitude circulation, and the interaction among different scales of motion are described in this paper. Four major meteorological scien-tific experiments in China with international cooperation were implemented in 1998: the South China Sea monsoon field experiment (SCSMEX), the Tibetan Plateau field experiment (TIPEX), the Huaihe River basin energy and water cycle experiment (HUBEX), and the South China heavy rain scientific experiment (HUAMEX). Although these field experiments have different scientific objectives, they commonly relate to monsoon activities and they interact with each other. The valuable intensive observation data that were obtained have already been shared internationally. Some new findings have been published recently. Other research work in China, such as the tropical air-sea interaction, tropical atmospheric circulation, and weather systems, are reviewed in this paper as well. Some research results have shown that the rainfall anomalies for different regions in China were closely related to the stages of El Nino events.展开更多
A cyber physical system(CPS)is a complex system that integrates sensing,computation,control and networking into physical processes and objects over Internet.It plays a key role in modern industry since it connects phy...A cyber physical system(CPS)is a complex system that integrates sensing,computation,control and networking into physical processes and objects over Internet.It plays a key role in modern industry since it connects physical and cyber worlds.In order to meet ever-changing industrial requirements,its structures and functions are constantly improved.Meanwhile,new security issues have arisen.A ubiquitous problem is the fact that cyber attacks can cause significant damage to industrial systems,and thus has gained increasing attention from researchers and practitioners.This paper presents a survey of state-of-the-art results of cyber attacks on cyber physical systems.First,as typical system models are employed to study these systems,time-driven and event-driven systems are reviewed.Then,recent advances on three types of attacks,i.e.,those on availability,integrity,and confidentiality are discussed.In particular,the detailed studies on availability and integrity attacks are introduced from the perspective of attackers and defenders.Namely,both attack and defense strategies are discussed based on different system models.Some challenges and open issues are indicated to guide future research and inspire the further exploration of this increasingly important area.展开更多
Environmental assessment in an arid coal mining area requires an understanding of the influences of coal mining,the arid climate and ecological remediation.To that end,we selected vegetation as the key environmental f...Environmental assessment in an arid coal mining area requires an understanding of the influences of coal mining,the arid climate and ecological remediation.To that end,we selected vegetation as the key environmental factor to observe.Remote sensing approaches to monitoring the spatio-temporal variation of vegetation caused by mining activities,the arid climate and ecological remediation in the Shengdong coal mining area are described.Over a large regional scale it was found that the vegetation was improved as a result of ecological remediation activities.At the local scale,however,the vegetation coverage and soil moisture in the mined areas were slightly lower than those in un-mined areas due to mining subsidence.These differences are partly attributed to ground fissures that injure root systems and increase the depletion of soil moisture.It is recommended that fissures be reduced and filled to lessen their adverse effects on the environment.展开更多
Reduction of Bama ilmenite concentrate containing 49.78% TiO2 and 27.96% total Fe by graphite was studied using thermogravimetric analysis system under argon gas ambient from 850 to 1 400 ℃. The reduction degree of B...Reduction of Bama ilmenite concentrate containing 49.78% TiO2 and 27.96% total Fe by graphite was studied using thermogravimetric analysis system under argon gas ambient from 850 to 1 400 ℃. The reduction degree of Bama ilmenite is enhanced with increasing temperature and the molar ratio of carbon to oxygen, and the reaction rate varies with temperature and reduction time simultaneously. The phase transformation, chemical composition, microstructure and morphology of reduced samples were investigated by using X-ray diffractometry, scanning electron microscopy, and energy disperse spectroscopy, respectively. The high content of impurities in Bama ilmenite evidently bates the reduction of ilmenite. Forming the enrichment zone of manganese prevents complete reduction of Fe2+. The reduction products are mostly reduced iron, rutile, reduced rutiles, Ti3O5 and pseudobrookite solid solution. The reduction kinetics was also discussed. The results show that the reduction temperature is a key factor to control reaction rate.展开更多
A discrete element model based on super-ellipsoids was used to simulate cylindrical particle flow. The model can describe a cylindrical particle accurately provided the shape indices of the super-ellipsoids are set to...A discrete element model based on super-ellipsoids was used to simulate cylindrical particle flow. The model can describe a cylindrical particle accurately provided the shape indices of the super-ellipsoids are set to appropriate values. To achieve more rapid calculations, we implemented an "oriented bounding box algorithm"(OBBA) for the initial contact detection of cylindrical particles. Several types of Simulations were performed to validate the super-ellipsoid model and the contact-detection algorithm. First, the effect of shape index of the super-ellipsoids on model accuracy was investigated through three simulations: impact of a cylindrical particle on a flat wall, flow of cylindrical particles in a rotating tumbler, and segregation of cylindrical particles of different length flowing down a bounded heap. The simulation results show that the super-ellipsoids describe cylindrical particles accurately when the shape index that specifies the sharpness of the cylinder edges is sufficiently large. The efficiency of the OBBA is measured by simulations in which a box is filled with cylindrical particles and a tumbler that contains cylindrical particles is rotated. The simulation results show that the OBBA can accelerate the calculations significantly. The effect of particle shape (such as aspect ratio and shape index) on the calculation speed was obtained. The simulation of rod-like particles tended to take more calculation time than that of disk-like particles, and the simulation time increased with an increasing particle-shape index.展开更多
A simplistic and novel leaching process is developed to dispose spent lithium iron phosphate(LiFePO_(4))batteries.In this paper,oxalic acid is selected as a leaching reagent to recover lithium as a resource and remove...A simplistic and novel leaching process is developed to dispose spent lithium iron phosphate(LiFePO_(4))batteries.In this paper,oxalic acid is selected as a leaching reagent to recover lithium as a resource and remove phosphorus from LiFePO_(4) batteries,benefiting from its low natural effects.The physical properties of spent cathode materials(before leaching)and residues(after leaching)are identified by X-ray diffraction(XRD)and scanning electronic microscopy(SEM)with energy dispersive X-ray spectroscopy(EDS).The total amounts of Li and Fe are analyzed by inductively coupled plasma-atomic emission spectroscopy(ICP-AES).The process occurs under conditions of a 0.3 mol·L^(-1) oxalic acid concentration,a temperature of 80℃,a reaction time of 60 min and a solid/liquid ratio of 60 g·L^(-1).It can effectively precipitate92%ferrum in terms of FeC_(2)O_(4)·2H_(2)O from LiFePO4,with the leaching efficiency of Li achieving up to 98%.This method demonstrates a new strategy for dealing with spent lithium iron phosphate batteries with a low cost and low environmental impact.展开更多
In this paper,a robust design method for current control is proposed to improve the performance of a three phase voltage source converter(VSC)with an inductorcapacitor-inductor(LCL)filter.The presence of the LCL filte...In this paper,a robust design method for current control is proposed to improve the performance of a three phase voltage source converter(VSC)with an inductorcapacitor-inductor(LCL)filter.The presence of the LCL filter complicates the dynamics of the control system and limits the achievable control bandwidth(and the overall performance),particularly when the uncertainty of the parameters is considered.To solve this problem,the advanced H?control theory is employed to design a robust current controller in stationary coordinates.Both control of the fundamental frequency current and suppression of the potential LC resonance are considered.The design procedure and the selection of the weight functions are presented in detail.A conventional proportional-resonant PR controller is also designed for comparison.Analysis showed that the proposed H∞ current controller achieved a good frequency response with explicit robustness.The conclusion was verified on a 5 kW VSC that had a LCL filter.展开更多
The global energy transition is a widespread phenomenon that requires international exchange of experiences and mutual learning.Germany’s success in its first phase of energy transition can be attributed to its adopt...The global energy transition is a widespread phenomenon that requires international exchange of experiences and mutual learning.Germany’s success in its first phase of energy transition can be attributed to its adoption of smart energy technology and implementation of electricity futures and spot marketization,which enabled the achievement of multiple energy spatial–temporal complementarities and overall grid balance through energy conversion and reconversion technologies.While China can draw from Germany’s experience to inform its own energy transition efforts,its 11-fold higher annual electricity consumption requires a distinct approach.We recommend a clean energy system based on smart sector coupling(ENSYSCO)as a suitable pathway for achieving sustainable energy in China,given that renewable energy is expected to guarantee 85%of China’s energy production by 2060,requiring significant future electricity storage capacity.Nonetheless,renewable energy storage remains a significant challenge.We propose four large-scale underground energy storage methods based on ENSYSCO to address this challenge,while considering China’s national conditions.These proposals have culminated in pilot projects for large-scale underground energy storage in China,which we believe is a necessary choice for achieving carbon neutrality in China and enabling efficient and safe grid integration of renewable energy within the framework of ENSYSCO.展开更多
Metal-nitrogen doped carbon catalysts(M-N/C) with abundantly accessible M-Nxsites, particularly single metal atom M-N/C(SAM-N/C), have been developed as a substitute for expensive Pt-based catalysts.These catalysts ar...Metal-nitrogen doped carbon catalysts(M-N/C) with abundantly accessible M-Nxsites, particularly single metal atom M-N/C(SAM-N/C), have been developed as a substitute for expensive Pt-based catalysts.These catalysts are used to increase the efficiency of otherwise sluggish oxygen reduction reactions(ORR) and hydrogen evolution reactions(HER). However, although the agglomerated metal nanoparticles are usually easy to form, they are very difficult to remove due to the protective surface-coating carbon layers, a factor that significantly hampers SAM-N/C fabrication. Herein, we report a one-step pyrolysis approach to successfully fabricate single cobalt atom Co-N/C(SACo-N/C) by using a Co2+-SCN-coordination compound as the metal precursor. Thanks to the decomposition of Co2+-SCN-compound at lower temperature than that of carbon layer deposition, Co-rich particles grow up to larger ones before carbon layers formation. Even though encapsulated by the carbon layers, it is difficult for the large Co-rich particle to be completely sealed. And thus, it makes the Co atoms possible to escape from incomplete carbon layer, to coordinate with nitrogen atoms, and to form SACo-N/C catalysts. This SACo-N/C exhibits excellent performances for both ORR(half-wave potential of 0.878 V) and HER(overpotential at 10 mA/cm2 of178 m V), and is thus a potential replacement for Pt-based catalysts. When SACo-N/C is integrated into a Zn-O2 battery, battery with high open-circuit voltage(1.536 V) has high peak power density(266 mW/cm2)and large gravimetric energy density(755 mA h/gZn) at current densities of 100 mA/cm2. Thus, we believe that this strategy may offer a new direction for the effective generation of SAM-N/C catalysts.展开更多
Molybdenum disulfide nanoflakes were synthesized by a simple hydrothermal process using sodium molybdate and thiourea as reactants at a relatively low temperature. X-ray diffraction(XRD) and transmission elec-tron mic...Molybdenum disulfide nanoflakes were synthesized by a simple hydrothermal process using sodium molybdate and thiourea as reactants at a relatively low temperature. X-ray diffraction(XRD) and transmission elec-tron microscopy(TEM) indicate that the samples have the structure of 2H-MoS2 and the morphology of nanoflakes with the average thickness around 5-10 nm. The results of electrochemical properties indicate that the morphology and size of MoS2 particles have effects on their capacity when they are used as the anode for lithium ion battery. The as-prepared MoS2 samples have high reversible discharge capacity up to 994.6 mA·h·g-1 for the MoS2-1 elec-trode and 930.1 mA·h·g-1 for the MoS2-2 electrode and show excellent cycling performances. The MoS2-1 electrode has a better cycling stability than the MoS2-2 electrode due to their difference in the uniformity of the samples.展开更多
The rapid improvement in the gel polymer electrolytes(GPEs)with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries.The combination of solvent and polymer enables quas...The rapid improvement in the gel polymer electrolytes(GPEs)with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries.The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs.However,different ion transport capacity between solvent and polymer will cause local nonuniform Li+distribution,leading to severe dendrite growth.In addition,the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes.Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs.Here,a strategy by introducing ion-conducting arrays(ICA)is created by vertical-aligned montmorillonite into GPE.Rapid ion transport on the ICA was demonstrated by 6Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction,combined with computer simulations to visualize the transport process.Compared with conventional randomly dispersed fillers,ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures.Therefore,GPE/ICA exhibits high room-temperature ionic conductivity(1.08 mS cm^(−1))and long-term stable Li deposition/stripping cycles(>1000 h).As a final proof,Li||GPE/ICA||LiFePO_(4) cells exhibit excellent cycle performance at wide temperature range(from 0 to 60°C),which shows a promising path toward all-weather practical solid-state batteries.展开更多
Lithium-ion batteries(LIBs), as the first choice for green batteries, have been widely used in energy storage, electric vehicles, 3C devices, and other related fields, and will have greater application prospects in th...Lithium-ion batteries(LIBs), as the first choice for green batteries, have been widely used in energy storage, electric vehicles, 3C devices, and other related fields, and will have greater application prospects in the future. However, one of the obstacles hindering the future development of battery technology is how to accurately evaluate and monitor battery health, which affects the entire lifespan of battery use. It is not enough to assess battery health comprehensively through the state of health(SoH) alone, especially when nonlinear aging occurs in onboard applications. Here, for the first time, we propose a brand-new health evaluation indicator—state of nonlinear aging(SoNA) to explain the nonlinear aging phenomenon that occurs during the battery use, and also design a knee-point identification method and two SoNA quantitative methods. We apply our health evaluation indicator to build a complete LIB full-lifespan grading evaluation system and a ground-to-cloud service framework, which integrates multi-scenario data collection, multi-dimensional data-based grading evaluation, and cloud management functions. Our works fill the gap in the LIBs’ health evaluation of nonlinear aging, which is of great significance for the health and safety evaluation of LIBs in the field of echelon utilization such as vehicles and energy storage. In addition, this comprehensive evaluation system and service framework are expected to be extended to other battery material systems other than LIBs, yet guiding the design of new energy ecosystem.展开更多
Surgery is the comm on treatme nt for early lung cancer with multiple pulm onary no dules,but it is often accompanied by the problem of significant malignancy of other nodules in non-therapeutic areas.In this study,we...Surgery is the comm on treatme nt for early lung cancer with multiple pulm onary no dules,but it is often accompanied by the problem of significant malignancy of other nodules in non-therapeutic areas.In this study,we found that a combined treatment of local rad iofreq ue ncy ablati on(RFA)and melatonin(MLT)greatly improved clinical outcomes for early lung cancer patie nts with multiple pulmonary nodules by minimizing lung function injury and reducing the probability of malignant transformation or enlargement of nodules in non-ablated areas.Mechanically,as demonstrated in an associated mouse lung tumor model,RFA not only effectively remove treated tumors but also stimulate antitumor immunity,which could inhibit tumor growth in non-ablated areas.MLT enhanced RFA-stimulated NK activity and exerted synergistic antitumor effects with RFA.Transcriptomics and proteomics analyses of residual tumor tissues revealed enhanced oxidative phosphorylation and reduced acidification as well as hypoxia in the tumor microenvironment,which suggests reprogrammed tumor metabolism after combined treatment with RFA and MLT.Analysis of residual tumor further revealed the depressed activity of MAPK,NF-kappa B,Wnt,and Hedgehog pathways and upregulated P53 pathway in tumors,which was in line with the inhibited tumor growth.Combined RFA and MLT treatment also reversed the Warburg effect and decreased tumor malignancy.These findings thus demonstrated that combined treatment of RFA and MLT effectively inhibited the malignancy of non-ablated nodules and provided an innovative non-invasive strategy for treating early lung tumors with multiple pulmonary nodules.Trial registration:www.chictr.org.cn,identifier ChiCTR2100042695,http://www.chictr.org.cn/showproj.aspx?proj=120931.展开更多
Carbon neutrality(or climate neutrality)has been a global consensus,and international experience exchange is essential.Given the differences in the degree of social development,resource endowment and technological lev...Carbon neutrality(or climate neutrality)has been a global consensus,and international experience exchange is essential.Given the differences in the degree of social development,resource endowment and technological level,each country should build a carbon-neutral plan based on its national conditions.Compared with other major developed countries(e.g.,Germany,the United States and Japan),China's carbon neutrality has much bigger challenges,including a heavy and time-pressured carbon reduction task and the current energy structure that is over-dependent on fossil fuels.Here we provide a comprehensive review of the status and prospects of the key technologies for low-carbon,near-zero carbon,and negative carbon emissions.Technological innovations associated with coal,oil-gas and hydrogen industries and their future potential in reducing carbon emissions are particularly explained and assessed.Based on integrated analysis of international experience from the world's major developed countries,in-depth knowledge of the current and future technologies,and China's energy and ecological resources potential,five lessons for the implementation of China's carbon neutrality are proposed:(1)transformation of energy production pattern from a coal-dominated pattern to a diversified renewable energy pattern;(2)renewable power-to-X and large-scale underground energy storage;(3)integration of green hydrogen production,storage,transport and utilization;(4)construction of clean energy systems based on smart sector coupling(ENSYSCO);(5)improvement of ecosystem carbon sinks both in nationwide forest land and potential desert in Northwest China.This paper provides an international perspective for a better understanding of the challenges and opportunities of carbon neutrality in China,and can serve as a theoretical foundation for medium-long term carbon neutral policy formulation.展开更多
In China, combustion of fossil fuels and biomass has produced serious air pollution that does harm to human health. Based on dose-response relationships derived from epidemiological studies, the authors calculated the...In China, combustion of fossil fuels and biomass has produced serious air pollution that does harm to human health. Based on dose-response relationships derived from epidemiological studies, the authors calculated the number of deaths and people with health problems which were thought to be attributable to China＇s air pollution in the year of 2000. In order to estimate the corresponding economic impacts from the national point of view, the general equilibrium approach was selected as an analysis tool for this study. A computable general equilibrium （CGE） model was constructed involving 39 sectors and 32 commodities. The human capital approach （HCA） was also used for comparison. The economic burden of disease for people estimated by HCA was equivalent to 1.26‰ （ranging from 0.44‰ to 1.84‰） of China＇s gross domestic product （GDP）. China＇s GDP loss estimated by the general equilibrium approach reached 0.38‰ （ranging from 0.16‰ to 0.51‰）. The difference between the two approaches and the implications of the results were discussed.展开更多
基金supported by the 111 Project (No.B07028)the Project for New Century Talents of Ministry of Education of China (No.NCET-04-0487)supported by the Natural Science Foundation of Jiangsu Province of China (No.50574095)
文摘The environmental challenges from coal mining include coal mine accidents,land subsidence,damage to the water environment,mining waste disposal and air pollution.These are either environmental pollution or landscape change.A conceptual framework for solving mine environmental issues is proposed.Clean processes,or remediation measures,are designed to address environmental pollution.Restoration measures are proposed to handle landscape change.The total methane drainage from 56 Chinese high methane concentration coal mines is about 101.94 million cubic meters.Of this methane,19.32 million,35.58 million and 6.97 million cubic meters are utilized for electricity generation,civil fuel supplies and other industrial purposes,respectively.About 39% of the methane is emitted into the atmosphere.The production of coal mining wastes can be decreased 10% by reuse of mining wastes as underground fills,or by using the waste as fuel for power plants or for raw material to make bricks or other infrastructure materials.The proper use of mined land must be decided in terms of local physical and socio-economical conditions.In European countries more than 50% of previously mined lands are reclaimed as forest or grass lands.However,in China more than 70% of the mined lands are reclaimed for agricultural purposes because the large population and a shortage of farmlands make this necessary.Reconstruction of rural communities or native residential improvement is one environmental problem arising from mining.We suggest two ways to reconstruct a farmer's house in China.
基金supported by Special Fund of the National Basic Research Program of China ("973" Program),Grant Nos. 2009CB219701,2010CB234608)Tianjin Municipal Science and Technology Development Program of China (Grant No. 09JCZDJC25000)+1 种基金Research Fund for the Doctoral Program of Higher Education of China (Grant No.20090032110064)Pacific Institute for Climate Solutions (PICS)
文摘With the specific characteristics of low-carbon intensity and economy,wind power has been widely promoted around the world.Due to the variable and intermittent nature of wind power production,the system has to frequently redispatch generators in order to ensure the effective use of wind power whilst maintaining system security.In this way,traditional generation costs are increased and the social benefit of wind power decreases indirectly.In this paper,a new regulation strategy based on power flow tracing was proposed,taking advantage of a comfort-constrained demand response strategy to follow the fluctuations of wind farm output,with the remaining imbalance of active power compensated by traditional generators.Examples showed that compared with conventional regulation,demand response could reduce the gross operating costs of the system,and the rapid response could help maintaining system stability in case of contingency.The strategy in this paper also applies to other large-scale integration problems associated with renewable energy resources which display short-term production variability.
基金supported by the National Natural Science Foundation of China under Grant Nos.40175019 and 40275018the Key Project of the Ministry of Science and Technology of China under Grant No.2001DIA20026.
文摘There has been much progress in the study of tropical cyclones and tropical meteorology in China in the past few years. A new atmospheric field experiment of tropical cyclone landfall with the acronym of CLATEX (China Landfalling Typhoon Experiment) was implemented in July-August 2002. The boundary layer characteristics of the target typhoon Vongfong and the mesoscale structural features of other land-falling typhoons were studied. In addition, typhoon track operational forecasting errors in the last decade have been reduced because the operational monitoring equipment and forecast techniques were improved. Some results from the research program on tropical cvclone landfall, structure and intensity change, inten-sification near coastal waters, interaction between tropical cyclone and mid-latitude circulation, and the interaction among different scales of motion are described in this paper. Four major meteorological scien-tific experiments in China with international cooperation were implemented in 1998: the South China Sea monsoon field experiment (SCSMEX), the Tibetan Plateau field experiment (TIPEX), the Huaihe River basin energy and water cycle experiment (HUBEX), and the South China heavy rain scientific experiment (HUAMEX). Although these field experiments have different scientific objectives, they commonly relate to monsoon activities and they interact with each other. The valuable intensive observation data that were obtained have already been shared internationally. Some new findings have been published recently. Other research work in China, such as the tropical air-sea interaction, tropical atmospheric circulation, and weather systems, are reviewed in this paper as well. Some research results have shown that the rainfall anomalies for different regions in China were closely related to the stages of El Nino events.
基金supported by Institutional Fund Projects(IFPNC-001-135-2020)technical and financial support from the Ministry of Education and King Abdulaziz University,DSR,Jeddah,Saudi Arabia。
文摘A cyber physical system(CPS)is a complex system that integrates sensing,computation,control and networking into physical processes and objects over Internet.It plays a key role in modern industry since it connects physical and cyber worlds.In order to meet ever-changing industrial requirements,its structures and functions are constantly improved.Meanwhile,new security issues have arisen.A ubiquitous problem is the fact that cyber attacks can cause significant damage to industrial systems,and thus has gained increasing attention from researchers and practitioners.This paper presents a survey of state-of-the-art results of cyber attacks on cyber physical systems.First,as typical system models are employed to study these systems,time-driven and event-driven systems are reviewed.Then,recent advances on three types of attacks,i.e.,those on availability,integrity,and confidentiality are discussed.In particular,the detailed studies on availability and integrity attacks are introduced from the perspective of attackers and defenders.Namely,both attack and defense strategies are discussed based on different system models.Some challenges and open issues are indicated to guide future research and inspire the further exploration of this increasingly important area.
基金supported by the Scientific Research Foundation of Jiangsu Key Laboratory of Resources and Environmental Information Engineering (No.JS200904)the Program of Education Ministry for Changjiang Scholars and Innovative Research Team(No.IRT0865).
文摘Environmental assessment in an arid coal mining area requires an understanding of the influences of coal mining,the arid climate and ecological remediation.To that end,we selected vegetation as the key environmental factor to observe.Remote sensing approaches to monitoring the spatio-temporal variation of vegetation caused by mining activities,the arid climate and ecological remediation in the Shengdong coal mining area are described.Over a large regional scale it was found that the vegetation was improved as a result of ecological remediation activities.At the local scale,however,the vegetation coverage and soil moisture in the mined areas were slightly lower than those in un-mined areas due to mining subsidence.These differences are partly attributed to ground fissures that injure root systems and increase the depletion of soil moisture.It is recommended that fissures be reduced and filled to lessen their adverse effects on the environment.
基金Project supported by the National Natural Science Foundation of China(No.51805470)the Zhejiang Provincial Natural Science Foundation of China(No.LY20E050016)+2 种基金the Zhejiang Provincial Key Research&Development Project(No.2019C01025)the Youth Funds of the State Key Laboratory of Fluid Power and Mechatronic Systems(Zhejiang University)(No.SJKo FP-QN-1801)the Zhejiang Provincial Quality and Technical Supervision Research Project(No.20180117),China
文摘Reduction of Bama ilmenite concentrate containing 49.78% TiO2 and 27.96% total Fe by graphite was studied using thermogravimetric analysis system under argon gas ambient from 850 to 1 400 ℃. The reduction degree of Bama ilmenite is enhanced with increasing temperature and the molar ratio of carbon to oxygen, and the reaction rate varies with temperature and reduction time simultaneously. The phase transformation, chemical composition, microstructure and morphology of reduced samples were investigated by using X-ray diffractometry, scanning electron microscopy, and energy disperse spectroscopy, respectively. The high content of impurities in Bama ilmenite evidently bates the reduction of ilmenite. Forming the enrichment zone of manganese prevents complete reduction of Fe2+. The reduction products are mostly reduced iron, rutile, reduced rutiles, Ti3O5 and pseudobrookite solid solution. The reduction kinetics was also discussed. The results show that the reduction temperature is a key factor to control reaction rate.
基金the China Scholarship Council and the National Natural Science Foundation of China (NSFC, Grant No. 51741608)thanks Austin Isner for help with data processing. The authors thank Guillaume Adoneth and Quentin Mougeot for acquiring experimental data on the seg-regation of cylindrical particles in a quasi-2D bounded heap.
文摘A discrete element model based on super-ellipsoids was used to simulate cylindrical particle flow. The model can describe a cylindrical particle accurately provided the shape indices of the super-ellipsoids are set to appropriate values. To achieve more rapid calculations, we implemented an "oriented bounding box algorithm"(OBBA) for the initial contact detection of cylindrical particles. Several types of Simulations were performed to validate the super-ellipsoid model and the contact-detection algorithm. First, the effect of shape index of the super-ellipsoids on model accuracy was investigated through three simulations: impact of a cylindrical particle on a flat wall, flow of cylindrical particles in a rotating tumbler, and segregation of cylindrical particles of different length flowing down a bounded heap. The simulation results show that the super-ellipsoids describe cylindrical particles accurately when the shape index that specifies the sharpness of the cylinder edges is sufficiently large. The efficiency of the OBBA is measured by simulations in which a box is filled with cylindrical particles and a tumbler that contains cylindrical particles is rotated. The simulation results show that the OBBA can accelerate the calculations significantly. The effect of particle shape (such as aspect ratio and shape index) on the calculation speed was obtained. The simulation of rod-like particles tended to take more calculation time than that of disk-like particles, and the simulation time increased with an increasing particle-shape index.
基金This work was supported by the International Science and Technology Cooperation Program of China(No.2016YFE0102200)SGCC’s Science&Technology Program(No.DG71-14-044).
文摘A simplistic and novel leaching process is developed to dispose spent lithium iron phosphate(LiFePO_(4))batteries.In this paper,oxalic acid is selected as a leaching reagent to recover lithium as a resource and remove phosphorus from LiFePO_(4) batteries,benefiting from its low natural effects.The physical properties of spent cathode materials(before leaching)and residues(after leaching)are identified by X-ray diffraction(XRD)and scanning electronic microscopy(SEM)with energy dispersive X-ray spectroscopy(EDS).The total amounts of Li and Fe are analyzed by inductively coupled plasma-atomic emission spectroscopy(ICP-AES).The process occurs under conditions of a 0.3 mol·L^(-1) oxalic acid concentration,a temperature of 80℃,a reaction time of 60 min and a solid/liquid ratio of 60 g·L^(-1).It can effectively precipitate92%ferrum in terms of FeC_(2)O_(4)·2H_(2)O from LiFePO4,with the leaching efficiency of Li achieving up to 98%.This method demonstrates a new strategy for dealing with spent lithium iron phosphate batteries with a low cost and low environmental impact.
基金This research was supported by the CAS Fraunhofer Joint Doctoral Promotion Program(DPP)and the National High Technology Research and Development Program of China(863 program)(No.2011AA050204).
文摘In this paper,a robust design method for current control is proposed to improve the performance of a three phase voltage source converter(VSC)with an inductorcapacitor-inductor(LCL)filter.The presence of the LCL filter complicates the dynamics of the control system and limits the achievable control bandwidth(and the overall performance),particularly when the uncertainty of the parameters is considered.To solve this problem,the advanced H?control theory is employed to design a robust current controller in stationary coordinates.Both control of the fundamental frequency current and suppression of the potential LC resonance are considered.The design procedure and the selection of the weight functions are presented in detail.A conventional proportional-resonant PR controller is also designed for comparison.Analysis showed that the proposed H∞ current controller achieved a good frequency response with explicit robustness.The conclusion was verified on a 5 kW VSC that had a LCL filter.
基金Henan Institute for Chinese Development Strategy of Engineering&Technology(No.2022HENZDA02)the Science&Technology Department of Sichuan Province(No.2021YFH0010)。
文摘The global energy transition is a widespread phenomenon that requires international exchange of experiences and mutual learning.Germany’s success in its first phase of energy transition can be attributed to its adoption of smart energy technology and implementation of electricity futures and spot marketization,which enabled the achievement of multiple energy spatial–temporal complementarities and overall grid balance through energy conversion and reconversion technologies.While China can draw from Germany’s experience to inform its own energy transition efforts,its 11-fold higher annual electricity consumption requires a distinct approach.We recommend a clean energy system based on smart sector coupling(ENSYSCO)as a suitable pathway for achieving sustainable energy in China,given that renewable energy is expected to guarantee 85%of China’s energy production by 2060,requiring significant future electricity storage capacity.Nonetheless,renewable energy storage remains a significant challenge.We propose four large-scale underground energy storage methods based on ENSYSCO to address this challenge,while considering China’s national conditions.These proposals have culminated in pilot projects for large-scale underground energy storage in China,which we believe is a necessary choice for achieving carbon neutrality in China and enabling efficient and safe grid integration of renewable energy within the framework of ENSYSCO.
基金supported by the National Key Research and Development Program of China(2016YFB0101202)the National Natural Science Foundation of China(21761162015,91534205,21436003)the Fundamental Research Funds for the Central Universities
文摘Metal-nitrogen doped carbon catalysts(M-N/C) with abundantly accessible M-Nxsites, particularly single metal atom M-N/C(SAM-N/C), have been developed as a substitute for expensive Pt-based catalysts.These catalysts are used to increase the efficiency of otherwise sluggish oxygen reduction reactions(ORR) and hydrogen evolution reactions(HER). However, although the agglomerated metal nanoparticles are usually easy to form, they are very difficult to remove due to the protective surface-coating carbon layers, a factor that significantly hampers SAM-N/C fabrication. Herein, we report a one-step pyrolysis approach to successfully fabricate single cobalt atom Co-N/C(SACo-N/C) by using a Co2+-SCN-coordination compound as the metal precursor. Thanks to the decomposition of Co2+-SCN-compound at lower temperature than that of carbon layer deposition, Co-rich particles grow up to larger ones before carbon layers formation. Even though encapsulated by the carbon layers, it is difficult for the large Co-rich particle to be completely sealed. And thus, it makes the Co atoms possible to escape from incomplete carbon layer, to coordinate with nitrogen atoms, and to form SACo-N/C catalysts. This SACo-N/C exhibits excellent performances for both ORR(half-wave potential of 0.878 V) and HER(overpotential at 10 mA/cm2 of178 m V), and is thus a potential replacement for Pt-based catalysts. When SACo-N/C is integrated into a Zn-O2 battery, battery with high open-circuit voltage(1.536 V) has high peak power density(266 mW/cm2)and large gravimetric energy density(755 mA h/gZn) at current densities of 100 mA/cm2. Thus, we believe that this strategy may offer a new direction for the effective generation of SAM-N/C catalysts.
基金国家自然科学基金项目“SNPs提升CO_(2)地质封存泥岩盖层封堵能力的作用机制研究”(42272176)中德合作交流项目,SINOGERMAN MOBILITY PROGRAMME“Mechanisms of flow-chemistry-biology coupling and enhanced caprock integrity in CO_(2) geological sequestration based on the synergistic effect of nanoparticles and methanogens”(M0469)。
基金Supported partially by the State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology,Zhejiang University of TechnologyPriority Research Centers Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education,Science and Technology (2009-0094047)
文摘Molybdenum disulfide nanoflakes were synthesized by a simple hydrothermal process using sodium molybdate and thiourea as reactants at a relatively low temperature. X-ray diffraction(XRD) and transmission elec-tron microscopy(TEM) indicate that the samples have the structure of 2H-MoS2 and the morphology of nanoflakes with the average thickness around 5-10 nm. The results of electrochemical properties indicate that the morphology and size of MoS2 particles have effects on their capacity when they are used as the anode for lithium ion battery. The as-prepared MoS2 samples have high reversible discharge capacity up to 994.6 mA·h·g-1 for the MoS2-1 elec-trode and 930.1 mA·h·g-1 for the MoS2-2 electrode and show excellent cycling performances. The MoS2-1 electrode has a better cycling stability than the MoS2-2 electrode due to their difference in the uniformity of the samples.
基金This work was supported partially by the National Natural Science Foundation of China(No.51973171)China Postdoctoral Science Foundation(No.2019M663687)+1 种基金National Natural Science Foundation of China(No.52105587),the Foundation of State Key Laboratory of Organic-Inorganic Composites(oic-202001003)the University Joint Project-Key Projects of Shaanxi Province(No.2021GXLH-Z-042).
文摘The rapid improvement in the gel polymer electrolytes(GPEs)with high ionic conductivity brought it closer to practical applications in solid-state Li-metal batteries.The combination of solvent and polymer enables quasi-liquid fast ion transport in the GPEs.However,different ion transport capacity between solvent and polymer will cause local nonuniform Li+distribution,leading to severe dendrite growth.In addition,the poor thermal stability of the solvent also limits the operating-temperature window of the electrolytes.Optimizing the ion transport environment and enhancing the thermal stability are two major challenges that hinder the application of GPEs.Here,a strategy by introducing ion-conducting arrays(ICA)is created by vertical-aligned montmorillonite into GPE.Rapid ion transport on the ICA was demonstrated by 6Li solid-state nuclear magnetic resonance and synchrotron X-ray diffraction,combined with computer simulations to visualize the transport process.Compared with conventional randomly dispersed fillers,ICA provides continuous interfaces to regulate the ion transport environment and enhances the tolerance of GPEs to extreme temperatures.Therefore,GPE/ICA exhibits high room-temperature ionic conductivity(1.08 mS cm^(−1))and long-term stable Li deposition/stripping cycles(>1000 h).As a final proof,Li||GPE/ICA||LiFePO_(4) cells exhibit excellent cycle performance at wide temperature range(from 0 to 60°C),which shows a promising path toward all-weather practical solid-state batteries.
基金financially supported by the National Natural Science Foundation of China(NSFC,U20A20310,52107230,52176199,52102470)the support of the research project Model2Life(03XP0334),funded by the German Federal Ministry of Education and Research(BMBF)。
文摘Lithium-ion batteries(LIBs), as the first choice for green batteries, have been widely used in energy storage, electric vehicles, 3C devices, and other related fields, and will have greater application prospects in the future. However, one of the obstacles hindering the future development of battery technology is how to accurately evaluate and monitor battery health, which affects the entire lifespan of battery use. It is not enough to assess battery health comprehensively through the state of health(SoH) alone, especially when nonlinear aging occurs in onboard applications. Here, for the first time, we propose a brand-new health evaluation indicator—state of nonlinear aging(SoNA) to explain the nonlinear aging phenomenon that occurs during the battery use, and also design a knee-point identification method and two SoNA quantitative methods. We apply our health evaluation indicator to build a complete LIB full-lifespan grading evaluation system and a ground-to-cloud service framework, which integrates multi-scenario data collection, multi-dimensional data-based grading evaluation, and cloud management functions. Our works fill the gap in the LIBs’ health evaluation of nonlinear aging, which is of great significance for the health and safety evaluation of LIBs in the field of echelon utilization such as vehicles and energy storage. In addition, this comprehensive evaluation system and service framework are expected to be extended to other battery material systems other than LIBs, yet guiding the design of new energy ecosystem.
基金supported by the National Natural Science Foundation of China(Nos.31770131,81473469)International Cooperation Project of the Belt and Road(No.20400750600)+1 种基金Shanghai Shen Kang Hospital Development Center Plan(SHDC12018119)Shanghai Municipal Commission of Health and Family Plan(201840056).
文摘Surgery is the comm on treatme nt for early lung cancer with multiple pulm onary no dules,but it is often accompanied by the problem of significant malignancy of other nodules in non-therapeutic areas.In this study,we found that a combined treatment of local rad iofreq ue ncy ablati on(RFA)and melatonin(MLT)greatly improved clinical outcomes for early lung cancer patie nts with multiple pulmonary nodules by minimizing lung function injury and reducing the probability of malignant transformation or enlargement of nodules in non-ablated areas.Mechanically,as demonstrated in an associated mouse lung tumor model,RFA not only effectively remove treated tumors but also stimulate antitumor immunity,which could inhibit tumor growth in non-ablated areas.MLT enhanced RFA-stimulated NK activity and exerted synergistic antitumor effects with RFA.Transcriptomics and proteomics analyses of residual tumor tissues revealed enhanced oxidative phosphorylation and reduced acidification as well as hypoxia in the tumor microenvironment,which suggests reprogrammed tumor metabolism after combined treatment with RFA and MLT.Analysis of residual tumor further revealed the depressed activity of MAPK,NF-kappa B,Wnt,and Hedgehog pathways and upregulated P53 pathway in tumors,which was in line with the inhibited tumor growth.Combined RFA and MLT treatment also reversed the Warburg effect and decreased tumor malignancy.These findings thus demonstrated that combined treatment of RFA and MLT effectively inhibited the malignancy of non-ablated nodules and provided an innovative non-invasive strategy for treating early lung tumors with multiple pulmonary nodules.Trial registration:www.chictr.org.cn,identifier ChiCTR2100042695,http://www.chictr.org.cn/showproj.aspx?proj=120931.
基金Project supported by the National Basic Research Program(973 Program)of China(No.2015CB057301)the National Natural Science Foundation of China(Nos.21676244 and 51373153)
基金supported by the Henan Institute for Chinese Development Strategy of Engineering&Technology(Grant No.2022HENZDA02)by the Science&Technology Department of Sichuan Province Project(Grant No.2021YFH0010).
文摘Carbon neutrality(or climate neutrality)has been a global consensus,and international experience exchange is essential.Given the differences in the degree of social development,resource endowment and technological level,each country should build a carbon-neutral plan based on its national conditions.Compared with other major developed countries(e.g.,Germany,the United States and Japan),China's carbon neutrality has much bigger challenges,including a heavy and time-pressured carbon reduction task and the current energy structure that is over-dependent on fossil fuels.Here we provide a comprehensive review of the status and prospects of the key technologies for low-carbon,near-zero carbon,and negative carbon emissions.Technological innovations associated with coal,oil-gas and hydrogen industries and their future potential in reducing carbon emissions are particularly explained and assessed.Based on integrated analysis of international experience from the world's major developed countries,in-depth knowledge of the current and future technologies,and China's energy and ecological resources potential,five lessons for the implementation of China's carbon neutrality are proposed:(1)transformation of energy production pattern from a coal-dominated pattern to a diversified renewable energy pattern;(2)renewable power-to-X and large-scale underground energy storage;(3)integration of green hydrogen production,storage,transport and utilization;(4)construction of clean energy systems based on smart sector coupling(ENSYSCO);(5)improvement of ecosystem carbon sinks both in nationwide forest land and potential desert in Northwest China.This paper provides an international perspective for a better understanding of the challenges and opportunities of carbon neutrality in China,and can serve as a theoretical foundation for medium-long term carbon neutral policy formulation.
文摘In China, combustion of fossil fuels and biomass has produced serious air pollution that does harm to human health. Based on dose-response relationships derived from epidemiological studies, the authors calculated the number of deaths and people with health problems which were thought to be attributable to China＇s air pollution in the year of 2000. In order to estimate the corresponding economic impacts from the national point of view, the general equilibrium approach was selected as an analysis tool for this study. A computable general equilibrium （CGE） model was constructed involving 39 sectors and 32 commodities. The human capital approach （HCA） was also used for comparison. The economic burden of disease for people estimated by HCA was equivalent to 1.26‰ （ranging from 0.44‰ to 1.84‰） of China＇s gross domestic product （GDP）. China＇s GDP loss estimated by the general equilibrium approach reached 0.38‰ （ranging from 0.16‰ to 0.51‰）. The difference between the two approaches and the implications of the results were discussed.
