Since the discovery of two-dimensional(2D)materials,they have garnered significant attention from researchers owing to the exceptional and modifiable physical and chemical properties.The weak interlayer interactions i...Since the discovery of two-dimensional(2D)materials,they have garnered significant attention from researchers owing to the exceptional and modifiable physical and chemical properties.The weak interlayer interactions in 2D materials enable precise control over Van der Waals gaps,thereby enhancing their performance and introducing novel characteristics.By regulating the Van der Waals gap,2D materials exhibit a diverse range of applications in the field of energy storage and conversion.This article provides a comprehensive review of various methods for manipulating Van der Waals gaps in 2D materials,including interlayer intercalation,vip atom doping within the lattice,formation of Van der Waals heterojunctions,and adjustment of stacking modes.Moreover,the impacts of these manipulations on energy storage and conversion applications are also summarized.Finally,potential future research directions are proposed to shed light on advancements in Van der Waals gap engineering.展开更多
Engineering a phosphide-based multifunctional heterostructure with high redox activity,stability,and efficient charge kinetics for both supercapacitors and water splitting remains challenging due to sluggish reaction ...Engineering a phosphide-based multifunctional heterostructure with high redox activity,stability,and efficient charge kinetics for both supercapacitors and water splitting remains challenging due to sluggish reaction kinetics and structural instability.This study overcomes these challenges by implementing a rapid,energy-efficient approach to develop a MOF-modulated MnP@Cu_(3)P heterostructure via a hydrothermal process followed by high-temperature phosphorization.The heterostructure demonstrates superior redox activity with enhanced stability and improved charge kinetics achieving a high specific capacity of 1131 C g^(-1)as supported by density functional theory findings of increased DOS near the Fermi level.The flexible supercapacitor achieves a peak energy density of 99.20 Wh kg^(-1)and power density of 15.40 kW kg^(-1).Simultaneously,it shows exceptional hydrogen evolution reaction performance with an overpotential of η_(10)=44 mV and η_(1000)=225 mV,attributed to electron transfer from Cu to Mn via P bridging,which shifts the active centers from Mn and Cu sites to the P site,confirmed by lowestΔG_(H)^(*)value of-0.16 eV.The overall water-splitting in full-cell electrocatalyzer delivers cell voltage of E_(20)=1.48 V and E_(1000)=1.88 V and setting a new standard in solar-to-hydrogen efficiency of 20.02%.The electrolyzer cell maintained prolonged stability at industrial-scale current densities of 1.0 A cm^(-2)under alkaline electrolysis achieving an estimated hydrogen production cost of INR 146.7 or US$1.67per kilogram aligning with the cost target of $2/kg by 2026 established by the Clean Hydrogen Electrolysis Program,U.S.department of energy.Furthermore,real-phase demonstration highlights the uninterrupted hydrogen production till 6-minutes via connecting this electrocatalyzer with photovoltaic-charged supercapacitors effectively addressing solar intermittency and gas fluctuations challenges in water-electrolysis.展开更多
Despite being an excellent candidate for a photocathode,Cu_(2)ZnSnS_4(CZTS)performance is limited by suboptimal bulk and interfacial charge carrier dynamics.In this work,we introduce a facile and versatile CZTS precur...Despite being an excellent candidate for a photocathode,Cu_(2)ZnSnS_4(CZTS)performance is limited by suboptimal bulk and interfacial charge carrier dynamics.In this work,we introduce a facile and versatile CZTS precursor seed layer engineering technique,which significantly enhances crystal growth and mitigates detrimental defects in the postsulfurized CZTS light-absorbing films.This effective optimization of defects and charge carrier dynamics results in a highly efficient CZTS/CdS/TiO_(2)/Pt thin-film photocathode,achieving a record half-cell solar-to-hydrogen(HC-STH)conversion efficiency of 9.91%.Additionally,the photocathode exhibits a highest photocurrent density(J_(ph))of 29.44 m A cm^(-2)(at 0 VRHE)and favorable onset potential(Von)of 0.73 VRHE.Furthermore,our CTZS photocathode demonstrates a remarkable Jph of 16.54 m A cm^(-2)and HC-STH efficiency of 2.56%in natural seawater,followed by an impressive unbiased STH efficiency of 2.20%in a CZTS-BiVO_4 tandem cell.The scalability of this approach is underscored by the successful fabrication of a 4×4 cm^(2)module,highlighting its significant potential for practical,unbiased in situ solar seawater splitting applications.展开更多
In the context of the current serious problems related to energy demand and climate change,substantial progress has been made in developing a sustainable energy system.Electrochemical hydrogen-water conversion is an i...In the context of the current serious problems related to energy demand and climate change,substantial progress has been made in developing a sustainable energy system.Electrochemical hydrogen-water conversion is an ideal energy system that can produce fuels via sustainable,fossil-free pathways.However,the energy conversion efficiency of two functioning technologies in this energy system—namely,water electrolysis and the fuel cell—still has great scope for improvement.This review analyzes the energy dissipation of water electrolysis and the fuel cell in the hydrogen-water energy system and discusses the key barriers in the hydrogen-and oxygen-involving reactions that occur on the catalyst surface.By means of the scaling relations between reactive intermediates and their apparent catalytic performance,this article summarizes the frameworks of the catalytic activity trends,providing insights into the design of highly active electrocatalysts for the involved reactions.A series of structural engineering methodologies(including nano architecture,facet engineering,polymorph engineering,amorphization,defect engineering,element doping,interface engineering,and alloying)and their applications based on catalytic performance are then introduced,w让h an emphasis on the rational guidance from previous theoretical and experimental studies.The key scientific problems in the electrochemical hydrogen-water conversion system are outlined,and future directions are proposed for developing advanced catalysts for technologies with high energy-conversion efficiency.展开更多
Recent development and recognition methods of raster to vector conversion for engineering drawings are presented. The advantages and disadvantages of all existing models are analyzed. Some research challenges and futu...Recent development and recognition methods of raster to vector conversion for engineering drawings are presented. The advantages and disadvantages of all existing models are analyzed. Some research challenges and future directions are discussed.展开更多
At present, with the development and progress of science and technology, social productivity is constantly improving, and the role of frequency conversion technology in coal mine mechanical and electrical equipment co...At present, with the development and progress of science and technology, social productivity is constantly improving, and the role of frequency conversion technology in coal mine mechanical and electrical equipment control is becoming more and more obvious. Frequency conversion technology has the advantages of regulation and control, etc. The application of this technology in mines can promote the production efficiency of transportation and ventilation. Frequency conversion technology is widely used in modern life. Applying frequency conversion technology to mining equipment in modern coal mine mechanical and electrical engineering can ensure the smooth operation of mechanical and electrical equipment to a great extent. Therefore, this paper will focus on the application of frequency conversion technology in modern coal mine electromechanical engineering.展开更多
H_(2)O_(2)is an environmentally friendly oxidant and a promising energy-containing molecule widely applied in industrial production,environmental remediation,and as a potential carrier for energy storage.Solar-driven ...H_(2)O_(2)is an environmentally friendly oxidant and a promising energy-containing molecule widely applied in industrial production,environmental remediation,and as a potential carrier for energy storage.Solar-driven conversion of earth-abundant H_(2)O and O_(2)is the most ideal method for producing H_(2)O_(2).Due to poor separation of photogenerated charge carriers in semiconductors,sacrificial reagents such as ethanol are typically added to consume photogenerated holes,but this is not an energy storage process.Therefore,developing efficient photocatalysts for direct H_(2)O_(2)production from H_(2)O and O_(2)without sacrificial agents is crucial for sustainable energy conversion.Organic framework materials,due to their customizable structures,have gained traction in the photosynthesis of H_(2)O_(2)from pure H_(2)O and O_(2).A series of functionalized molecules have been introduced as building blocks into organic frameworks to enhance the H_(2)O_(2)production performance,but their key roles in performance and reaction pathways have not been summarized in detail so far.This review aims to address this gap and elucidate the relationship between the structure and performance of organic framework photocatalysts,providing insights and guidance for the development of efficient photocatalysts.展开更多
The thermoelectric energy conversion technique by employing the Disk-Magnet Electromagnetic Induction (DM-EMI) is examined in detail, and possible applications to heat engines as one of the energy-harvesting technolog...The thermoelectric energy conversion technique by employing the Disk-Magnet Electromagnetic Induction (DM-EMI) is examined in detail, and possible applications to heat engines as one of the energy-harvesting technologies are discussed. The idea is induced by the analysis of thermomechanical dynamics (TMD) for a nonequilibrium irreversible thermodynamic system of heat engines, such as a drinking bird and a low temperature Stirling engine, resulting in thermoelectric energy generation different from conventional heat engines. The current thermoelectric energy conversion with DM-EMI can be applied to wide ranges of machines and temperature differences. The mechanism of DM-EMI energy converter is categorized as the axial flux generator (AFG), which is the reason why the technology is applicable to sensitive thermoelectric conversions. On the other hand, almost all the conventional turbines use the radius flux generator to extract huge electric power, which uses the radial flux generator (RFG). The axial flux generator is helpful for a low mechanoelectric energy conversion and activations of waste heat from macroscopic energy generators such as wind, geothermal, thermal, nuclear power plants and heat-dissipation lines. The technique of DM-EMI will contribute to solving environmental problems to maintain clean and sustainable energy as one of the energy harvesting technologies.展开更多
The integration of robust photon-absorption capacity,high reactive oxygen speciesyields and photothermal conversion efficiency(PCE)into a single phototheranosticnano-agents is ideal but rarely reported.This study empl...The integration of robust photon-absorption capacity,high reactive oxygen speciesyields and photothermal conversion efficiency(PCE)into a single phototheranosticnano-agents is ideal but rarely reported.This study employed a dual-acceptorengineering strategy utilizing isoindigo and selenium-substituted[1,2,5]thiadiazolo[3,4-c]pyridine to augment the molar extinction coefficient and spin-orbitcoupling effect,respectively,resulting in a substantial enhancement of photonabsorptionability and non-radiative decay energy-release process of donoracceptortype phototherapy molecules.As the optimal phototherapy agent,IID-PSe exhibited a high molar extinction coefficient two times that of photosensitizer,excellent 1O2 yield(15%)and PCE(34%),exhibiting great potential forphototherapy.After encapsulating with DSPE-PEG2000,IID-PSe NPs showedexcellent anti-tumor phototherapy ability both in vitro and in vivo.This workprovides an effective idea for designing high-performance photosensitive dyeswith high efficiency phototherapy output.展开更多
A novel steady-state optimization （SSO） of internal combustion engine （ICE） strategy is proposed to maximize the efficiency of the overall powertrain for hybrid electric vehicles, in which the ICE efficiency, the ...A novel steady-state optimization （SSO） of internal combustion engine （ICE） strategy is proposed to maximize the efficiency of the overall powertrain for hybrid electric vehicles, in which the ICE efficiency, the efficiencies of the electric motor （EM） and the energy storage device are all explicitly taken into account. In addition, a novel idle optimization of ICE strategy is implemented to obtain the optimal idle operating point of the ICE and corresponding optimal parking generation power of the EM using the view of the novel SSO of ICE strategy. Simulations results show that potential fuel economy improvement is achieved relative to the conventional one which only optimized the ICE efficiency by the novel SSO of ICE strategy, and fuel consumption per voltage increment decreases a lot during the parking charge by the novel idle optimization of ICE strategy.展开更多
Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine engines.In terms of limit protection control,a novel model-based multivariable limit protection control method,whic...Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine engines.In terms of limit protection control,a novel model-based multivariable limit protection control method,which is achieved by adaptive command reconstruction and multiplecontrol loop selection and switch logic,is proposed in this paper to address the problem of balancing smaller thrust loss and safe operations by comparing with widely-used Min-Max logic.Five different combination modes of control loops,which represent the online control loop of last time instant and that of current time instant,is analyzed.Different command reconstructions are designed for these modes,which is based on static gain conversion of amplitude beyond limits by using an onboard model.The double-prediction based control loop selection and switch logic is developed to choose a control loop appropriately by comparing converted amplitude beyond limits regardless of one or more parameters tending to exceed limits.The proposed method is implemented in a twin-spool turbofan engine to achieve limit protection with direct thrust control,and the loss of thrust is improved by about 30% in comparison with the loss of thrust caused by Min-Max logic when limit protection control is activated,which demonstrates the effectiveness of the proposed method.展开更多
Understanding the pore water conversion characteristics during hydrate formation in porous media is important to study the accumulation mechanism of marine gas hydrate.In this study,low-field NMR was used to study the...Understanding the pore water conversion characteristics during hydrate formation in porous media is important to study the accumulation mechanism of marine gas hydrate.In this study,low-field NMR was used to study the pore water conversion characteristics during methane hydrate formation in unsaturated sand samples.Results show that the signal intensity of T_(2) distribution isn’t affected by sediment type and pore pressure,but is affected by temperature.The increase in the pressure of hydrogen-containing gas can cause the increase in the signal intensity of T_(2) distribution.The heterogeneity of pore structure is aggravated due to the hydrate formation in porous media.The water conversion rate fluctuates during the hydrate formation.The sand size affects the water conversion ratio and rate by affecting the specific surface of sand in unsaturated porous media.For the fine sand sample,the large specific surface causes a large gas-water contact area resulting in a higher water conversion rate,but causes a large water-sand contact area resulting in a low water conversion ratio(C_(w)=96.2%).The clay can reduce the water conversion rate and ratio,especially montmorillonite(C_(w)=95.8%).The crystal layer of montmorillonite affects the pore water conversion characteristics by hindering the conversion of interlayer water.展开更多
Wells turbine has inherent disadvantages in comparison with conventional turbines: relative low efficiency at high flow coefficient and poor starting characteristics. To solve these problems, the authors propose Wells...Wells turbine has inherent disadvantages in comparison with conventional turbines: relative low efficiency at high flow coefficient and poor starting characteristics. To solve these problems, the authors propose Wells turbine with booster turbine for wave energy conversion, in order to improve the performance in this study. This turbine consists of three parts: a large Wells turbine, a small impulse turbine with fixed guide vanes for oscillating airflow, and a generator. It was conjectured that, by coupling the two axial flow turbines together, pneumatic energy from oscillating airflow is captured by Wells turbine at low flow coefficient and that the impulse turbine gets the energy at high flow coefficient. As the first step of this study on the proposed turbine topology, the performance of turbines under steady flow conditions has been investigated experimentally by model testings. Furthermore, we estimate mean efficiency of the turbine by quasi-steady analysis.展开更多
The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Moun...The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Mountain Area and Jianghan Plain.It’s a great field test site to study the material and energy exchange among rainfall,soil moisture,and groundwater of the Earth’s critical zone in subtropical monsoon climate plain areas.This paper analyzed the connection between rainfall and volume water content(VWC)of soil at different depths of several soil profiles,and the dynamic feature of groundwater was discussed,which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata.The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge,while the lateral recharge is the main supplement source.There were 75 effective rainfall events among 120 rainfall events during the monitoring period,with an accumulated amount of 672.9 mm,and the percentages of effective rainfall amount and duration time were 62.50%and 91.56%,respectively.The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m.The soil profile was divided into four zones:(1)The sensitive zone of rainfall infiltration within 1.4 m,where the material and energy exchange frequently near the interface between atmosphere and soil;(2)the buffer zone of rainfall infiltration between 1.4 m and 3.5 m;(3)the migration zone of rainfall infiltration between 3.5 m and 5.0 m;and(4)the rainfall infiltration and groundwater level co-influenced zone below 5.0 m.The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth’s critical zone,which is of great theoretical and practical significance for groundwater resources evaluation and development,groundwater environmental protection,ecological environmental improvement,drought disaster prevention,and flood disaster prevention in subtropical monsoon climate plain areas.展开更多
The compression stroke characteristics of free-piston engine generator were studied. The numerical model of the compression stroke was established based on thermodynamics and dynamics equation,and the leak loss,heat l...The compression stroke characteristics of free-piston engine generator were studied. The numerical model of the compression stroke was established based on thermodynamics and dynamics equation,and the leak loss,heat loss and friction loss were considered. Through solving numerical equations,the in-cylinder pressure of compression stroke under different compression ratios was calculated,energy transfer and conversion process was analyzed,and the calculated results were experimentally verified. The results showed that the actual effective output of electronic energy and the compression energy stored in the com-pressed gas accounted for about 70%. The compression energy gradually increased with the increasing com-pression ratio. When the compression ratio was more than 7. 5,the actual compression energy increased slowly and the energy error between simulation and test decreased.展开更多
基金financially supported by the National Key Technologies R&D Program of China(No.2022YFB2404300)the National Natural Science Foundation of China(No.22171016)+1 种基金the Fundamental Research Funds for the Central Universities and the Overseas Expertise Introduction Project for Discipline Innovation(111 Project)(No.B17002)supported by the Academic Excellence Foundation of BUAA for Ph.D.Students。
文摘Since the discovery of two-dimensional(2D)materials,they have garnered significant attention from researchers owing to the exceptional and modifiable physical and chemical properties.The weak interlayer interactions in 2D materials enable precise control over Van der Waals gaps,thereby enhancing their performance and introducing novel characteristics.By regulating the Van der Waals gap,2D materials exhibit a diverse range of applications in the field of energy storage and conversion.This article provides a comprehensive review of various methods for manipulating Van der Waals gaps in 2D materials,including interlayer intercalation,vip atom doping within the lattice,formation of Van der Waals heterojunctions,and adjustment of stacking modes.Moreover,the impacts of these manipulations on energy storage and conversion applications are also summarized.Finally,potential future research directions are proposed to shed light on advancements in Van der Waals gap engineering.
基金supported financially by the Ministry of Textiles(Grant No-2/3/2021-NTTM(Pt.)),Govt.of India。
文摘Engineering a phosphide-based multifunctional heterostructure with high redox activity,stability,and efficient charge kinetics for both supercapacitors and water splitting remains challenging due to sluggish reaction kinetics and structural instability.This study overcomes these challenges by implementing a rapid,energy-efficient approach to develop a MOF-modulated MnP@Cu_(3)P heterostructure via a hydrothermal process followed by high-temperature phosphorization.The heterostructure demonstrates superior redox activity with enhanced stability and improved charge kinetics achieving a high specific capacity of 1131 C g^(-1)as supported by density functional theory findings of increased DOS near the Fermi level.The flexible supercapacitor achieves a peak energy density of 99.20 Wh kg^(-1)and power density of 15.40 kW kg^(-1).Simultaneously,it shows exceptional hydrogen evolution reaction performance with an overpotential of η_(10)=44 mV and η_(1000)=225 mV,attributed to electron transfer from Cu to Mn via P bridging,which shifts the active centers from Mn and Cu sites to the P site,confirmed by lowestΔG_(H)^(*)value of-0.16 eV.The overall water-splitting in full-cell electrocatalyzer delivers cell voltage of E_(20)=1.48 V and E_(1000)=1.88 V and setting a new standard in solar-to-hydrogen efficiency of 20.02%.The electrolyzer cell maintained prolonged stability at industrial-scale current densities of 1.0 A cm^(-2)under alkaline electrolysis achieving an estimated hydrogen production cost of INR 146.7 or US$1.67per kilogram aligning with the cost target of $2/kg by 2026 established by the Clean Hydrogen Electrolysis Program,U.S.department of energy.Furthermore,real-phase demonstration highlights the uninterrupted hydrogen production till 6-minutes via connecting this electrocatalyzer with photovoltaic-charged supercapacitors effectively addressing solar intermittency and gas fluctuations challenges in water-electrolysis.
基金supported by National Natural Science Foundation of China(No.62474114,52472225)Guangdong Basic and Applied Basic Research Foundation(2025A1515012041,2025A1515011515)China+1 种基金Science and Technology plan project of Shenzhen(JCYJ20240813141620027,20231122102326002)ChinaShenzhen University 2035 Program for Excellent Research(Grants 2024B003)。
文摘Despite being an excellent candidate for a photocathode,Cu_(2)ZnSnS_4(CZTS)performance is limited by suboptimal bulk and interfacial charge carrier dynamics.In this work,we introduce a facile and versatile CZTS precursor seed layer engineering technique,which significantly enhances crystal growth and mitigates detrimental defects in the postsulfurized CZTS light-absorbing films.This effective optimization of defects and charge carrier dynamics results in a highly efficient CZTS/CdS/TiO_(2)/Pt thin-film photocathode,achieving a record half-cell solar-to-hydrogen(HC-STH)conversion efficiency of 9.91%.Additionally,the photocathode exhibits a highest photocurrent density(J_(ph))of 29.44 m A cm^(-2)(at 0 VRHE)and favorable onset potential(Von)of 0.73 VRHE.Furthermore,our CTZS photocathode demonstrates a remarkable Jph of 16.54 m A cm^(-2)and HC-STH efficiency of 2.56%in natural seawater,followed by an impressive unbiased STH efficiency of 2.20%in a CZTS-BiVO_4 tandem cell.The scalability of this approach is underscored by the successful fabrication of a 4×4 cm^(2)module,highlighting its significant potential for practical,unbiased in situ solar seawater splitting applications.
基金We gratefully acknowledge financial support from the National Natural Science Foundation of China(21576032 and 51772037)the Key Program of the National Natural Science Foundation of China(21436003)+1 种基金the Major Research Plan of the National Natural Science Foundation of China(91534205)the National Program on Key Basic Research Project of China(2016YFB0101202).
文摘In the context of the current serious problems related to energy demand and climate change,substantial progress has been made in developing a sustainable energy system.Electrochemical hydrogen-water conversion is an ideal energy system that can produce fuels via sustainable,fossil-free pathways.However,the energy conversion efficiency of two functioning technologies in this energy system—namely,water electrolysis and the fuel cell—still has great scope for improvement.This review analyzes the energy dissipation of water electrolysis and the fuel cell in the hydrogen-water energy system and discusses the key barriers in the hydrogen-and oxygen-involving reactions that occur on the catalyst surface.By means of the scaling relations between reactive intermediates and their apparent catalytic performance,this article summarizes the frameworks of the catalytic activity trends,providing insights into the design of highly active electrocatalysts for the involved reactions.A series of structural engineering methodologies(including nano architecture,facet engineering,polymorph engineering,amorphization,defect engineering,element doping,interface engineering,and alloying)and their applications based on catalytic performance are then introduced,w让h an emphasis on the rational guidance from previous theoretical and experimental studies.The key scientific problems in the electrochemical hydrogen-water conversion system are outlined,and future directions are proposed for developing advanced catalysts for technologies with high energy-conversion efficiency.
文摘Recent development and recognition methods of raster to vector conversion for engineering drawings are presented. The advantages and disadvantages of all existing models are analyzed. Some research challenges and future directions are discussed.
文摘At present, with the development and progress of science and technology, social productivity is constantly improving, and the role of frequency conversion technology in coal mine mechanical and electrical equipment control is becoming more and more obvious. Frequency conversion technology has the advantages of regulation and control, etc. The application of this technology in mines can promote the production efficiency of transportation and ventilation. Frequency conversion technology is widely used in modern life. Applying frequency conversion technology to mining equipment in modern coal mine mechanical and electrical engineering can ensure the smooth operation of mechanical and electrical equipment to a great extent. Therefore, this paper will focus on the application of frequency conversion technology in modern coal mine electromechanical engineering.
文摘H_(2)O_(2)is an environmentally friendly oxidant and a promising energy-containing molecule widely applied in industrial production,environmental remediation,and as a potential carrier for energy storage.Solar-driven conversion of earth-abundant H_(2)O and O_(2)is the most ideal method for producing H_(2)O_(2).Due to poor separation of photogenerated charge carriers in semiconductors,sacrificial reagents such as ethanol are typically added to consume photogenerated holes,but this is not an energy storage process.Therefore,developing efficient photocatalysts for direct H_(2)O_(2)production from H_(2)O and O_(2)without sacrificial agents is crucial for sustainable energy conversion.Organic framework materials,due to their customizable structures,have gained traction in the photosynthesis of H_(2)O_(2)from pure H_(2)O and O_(2).A series of functionalized molecules have been introduced as building blocks into organic frameworks to enhance the H_(2)O_(2)production performance,but their key roles in performance and reaction pathways have not been summarized in detail so far.This review aims to address this gap and elucidate the relationship between the structure and performance of organic framework photocatalysts,providing insights and guidance for the development of efficient photocatalysts.
文摘The thermoelectric energy conversion technique by employing the Disk-Magnet Electromagnetic Induction (DM-EMI) is examined in detail, and possible applications to heat engines as one of the energy-harvesting technologies are discussed. The idea is induced by the analysis of thermomechanical dynamics (TMD) for a nonequilibrium irreversible thermodynamic system of heat engines, such as a drinking bird and a low temperature Stirling engine, resulting in thermoelectric energy generation different from conventional heat engines. The current thermoelectric energy conversion with DM-EMI can be applied to wide ranges of machines and temperature differences. The mechanism of DM-EMI energy converter is categorized as the axial flux generator (AFG), which is the reason why the technology is applicable to sensitive thermoelectric conversions. On the other hand, almost all the conventional turbines use the radius flux generator to extract huge electric power, which uses the radial flux generator (RFG). The axial flux generator is helpful for a low mechanoelectric energy conversion and activations of waste heat from macroscopic energy generators such as wind, geothermal, thermal, nuclear power plants and heat-dissipation lines. The technique of DM-EMI will contribute to solving environmental problems to maintain clean and sustainable energy as one of the energy harvesting technologies.
基金supported by the National Natural Science Foundation of China(21925802,22338005,22308049)Liaoning Binhai Laboratory(LBLB-2023-03)+1 种基金the Fundamental Research Funds for the Central Universities(DUT22LAB601)the Postdoctoral ResearchFoundation of Ningbo Institute of Dalian University ofTechnology(03020002).
文摘The integration of robust photon-absorption capacity,high reactive oxygen speciesyields and photothermal conversion efficiency(PCE)into a single phototheranosticnano-agents is ideal but rarely reported.This study employed a dual-acceptorengineering strategy utilizing isoindigo and selenium-substituted[1,2,5]thiadiazolo[3,4-c]pyridine to augment the molar extinction coefficient and spin-orbitcoupling effect,respectively,resulting in a substantial enhancement of photonabsorptionability and non-radiative decay energy-release process of donoracceptortype phototherapy molecules.As the optimal phototherapy agent,IID-PSe exhibited a high molar extinction coefficient two times that of photosensitizer,excellent 1O2 yield(15%)and PCE(34%),exhibiting great potential forphototherapy.After encapsulating with DSPE-PEG2000,IID-PSe NPs showedexcellent anti-tumor phototherapy ability both in vitro and in vivo.This workprovides an effective idea for designing high-performance photosensitive dyeswith high efficiency phototherapy output.
基金National Hi-tech Research end Development Program of China (863 Program,No.2002AA501700,No.2003AA501012)
文摘A novel steady-state optimization （SSO） of internal combustion engine （ICE） strategy is proposed to maximize the efficiency of the overall powertrain for hybrid electric vehicles, in which the ICE efficiency, the efficiencies of the electric motor （EM） and the energy storage device are all explicitly taken into account. In addition, a novel idle optimization of ICE strategy is implemented to obtain the optimal idle operating point of the ICE and corresponding optimal parking generation power of the EM using the view of the novel SSO of ICE strategy. Simulations results show that potential fuel economy improvement is achieved relative to the conventional one which only optimized the ICE efficiency by the novel SSO of ICE strategy, and fuel consumption per voltage increment decreases a lot during the parking charge by the novel idle optimization of ICE strategy.
基金supported by China Scholarship Council(No.201906830081)。
文摘Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine engines.In terms of limit protection control,a novel model-based multivariable limit protection control method,which is achieved by adaptive command reconstruction and multiplecontrol loop selection and switch logic,is proposed in this paper to address the problem of balancing smaller thrust loss and safe operations by comparing with widely-used Min-Max logic.Five different combination modes of control loops,which represent the online control loop of last time instant and that of current time instant,is analyzed.Different command reconstructions are designed for these modes,which is based on static gain conversion of amplitude beyond limits by using an onboard model.The double-prediction based control loop selection and switch logic is developed to choose a control loop appropriately by comparing converted amplitude beyond limits regardless of one or more parameters tending to exceed limits.The proposed method is implemented in a twin-spool turbofan engine to achieve limit protection with direct thrust control,and the loss of thrust is improved by about 30% in comparison with the loss of thrust caused by Min-Max logic when limit protection control is activated,which demonstrates the effectiveness of the proposed method.
基金the financial support of the National Natural Science Foundation of China(41876051 and 41872136)the China Postdoctoral Science Foundation(2021M701815)the Postdoctoral Innovative Talents Support Program in Shandong Province(SDBX2021015).
文摘Understanding the pore water conversion characteristics during hydrate formation in porous media is important to study the accumulation mechanism of marine gas hydrate.In this study,low-field NMR was used to study the pore water conversion characteristics during methane hydrate formation in unsaturated sand samples.Results show that the signal intensity of T_(2) distribution isn’t affected by sediment type and pore pressure,but is affected by temperature.The increase in the pressure of hydrogen-containing gas can cause the increase in the signal intensity of T_(2) distribution.The heterogeneity of pore structure is aggravated due to the hydrate formation in porous media.The water conversion rate fluctuates during the hydrate formation.The sand size affects the water conversion ratio and rate by affecting the specific surface of sand in unsaturated porous media.For the fine sand sample,the large specific surface causes a large gas-water contact area resulting in a higher water conversion rate,but causes a large water-sand contact area resulting in a low water conversion ratio(C_(w)=96.2%).The clay can reduce the water conversion rate and ratio,especially montmorillonite(C_(w)=95.8%).The crystal layer of montmorillonite affects the pore water conversion characteristics by hindering the conversion of interlayer water.
文摘Wells turbine has inherent disadvantages in comparison with conventional turbines: relative low efficiency at high flow coefficient and poor starting characteristics. To solve these problems, the authors propose Wells turbine with booster turbine for wave energy conversion, in order to improve the performance in this study. This turbine consists of three parts: a large Wells turbine, a small impulse turbine with fixed guide vanes for oscillating airflow, and a generator. It was conjectured that, by coupling the two axial flow turbines together, pneumatic energy from oscillating airflow is captured by Wells turbine at low flow coefficient and that the impulse turbine gets the energy at high flow coefficient. As the first step of this study on the proposed turbine topology, the performance of turbines under steady flow conditions has been investigated experimentally by model testings. Furthermore, we estimate mean efficiency of the turbine by quasi-steady analysis.
基金the project“1:50000 regional hydrogeological survey in the Dabie Mountains contiguous destitute area”(121201009000172522)from Wuhan Center of Geological Survey,China Geological Survey(CGS).
文摘The scientific field test site of rainfall-soil moisture-groundwater conversion in Dabie Mountain Area–Jianghan Plain is located in the northern region of the Jianghan Plain,the transition zone between the Dabie Mountain Area and Jianghan Plain.It’s a great field test site to study the material and energy exchange among rainfall,soil moisture,and groundwater of the Earth’s critical zone in subtropical monsoon climate plain areas.This paper analyzed the connection between rainfall and volume water content(VWC)of soil at different depths of several soil profiles,and the dynamic feature of groundwater was discussed,which reveals the rainfall infiltration recharge of Quaternary Upper Pleistocene strata.The results show that the Quaternary Upper Pleistocene aquifer groundwater accepts a little direct rainfall recharge,while the lateral recharge is the main supplement source.There were 75 effective rainfall events among 120 rainfall events during the monitoring period,with an accumulated amount of 672.9 mm,and the percentages of effective rainfall amount and duration time were 62.50%and 91.56%,respectively.The max evaporation depth at the upper part in Quaternary cohesive soil was no less than 1.4 m.The soil profile was divided into four zones:(1)The sensitive zone of rainfall infiltration within 1.4 m,where the material and energy exchange frequently near the interface between atmosphere and soil;(2)the buffer zone of rainfall infiltration between 1.4 m and 3.5 m;(3)the migration zone of rainfall infiltration between 3.5 m and 5.0 m;and(4)the rainfall infiltration and groundwater level co-influenced zone below 5.0 m.The results revealed the reaction of soil moisture and groundwater to rainfall in the area covered by cohesive soil under humid climate in Earth’s critical zone,which is of great theoretical and practical significance for groundwater resources evaluation and development,groundwater environmental protection,ecological environmental improvement,drought disaster prevention,and flood disaster prevention in subtropical monsoon climate plain areas.
基金Supported by the National Natural Science Foundation of China(51006010)the Program of Introducing Talents of Discipline to Universities(B12022)
文摘The compression stroke characteristics of free-piston engine generator were studied. The numerical model of the compression stroke was established based on thermodynamics and dynamics equation,and the leak loss,heat loss and friction loss were considered. Through solving numerical equations,the in-cylinder pressure of compression stroke under different compression ratios was calculated,energy transfer and conversion process was analyzed,and the calculated results were experimentally verified. The results showed that the actual effective output of electronic energy and the compression energy stored in the com-pressed gas accounted for about 70%. The compression energy gradually increased with the increasing com-pression ratio. When the compression ratio was more than 7. 5,the actual compression energy increased slowly and the energy error between simulation and test decreased.
