Based on the complementary advantages of Line Commutated Converter(LCC)and Modular Multilevel Converter(MMC)in power grid applications,there are two types of hybrid DC system topologies:one is the parallel connection ...Based on the complementary advantages of Line Commutated Converter(LCC)and Modular Multilevel Converter(MMC)in power grid applications,there are two types of hybrid DC system topologies:one is the parallel connection of LCC converter stations and MMC converter stations,and the other is the series connection of LCC and MMC converter stations within a single station.The hybrid DC transmission system faces broad application prospects and development potential in large-scale clean energy integration across regions and the construction of a new power system dominated by new energy sources in China.This paper first analyzes the system forms and topological characteristics of hybrid DC transmission,introducing the forms and topological characteristics of converter-level hybrid DC transmission systems and system-level hybrid DC transmission systems.Next,it analyzes the operating characteristics of LCC and MMC inverter-level hybrid DC transmission systems,provides insights into the transient stability of hybrid DC transmission systems,and typical fault ride-through control strategies.Finally,it summarizes the networking characteristics of the LCC-MMC series within the converter station hybrid DC transmission system,studies the transient characteristics and fault ridethrough control strategies under different fault types for the LCC-MMC series in the receiving-end converter station,and investigates the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the sending-end converter station.展开更多
Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling ca...Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features.Firstly,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis.Secondly,the screw theory is employed to analyze the degree of freedom(DoF)of the capture mechanism.Then,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried out.Combined with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried out.Furthermore,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed.Finally,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed.The work provides technical reserves for the research and development of AUV capture special equipment.展开更多
Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges r...Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges related to inadequate mass transfer and a high pressure drop caused by the non-uniform void fraction distribution.To enhance the overall performance of fixed beds,the impact of different packing configurations on performance was investigated.Experimental and simulation methods were used to investigate the fluid flow and mass transfer performances of various packed beds under different flow rates.It was found that structured beds exhibited a significantly lower pressure drop per unit length than conventional packed beds.Furthermore,the packing configurations had a critical role in improving the overall performance of fixed beds.Specifically,structured packed beds,particularly the H-2 packing configuration,effectively reduced the pressure drop per unit length and improved the mass transfer efficiency.The H-2 packing configuration consisted of two parallel strips of particles in each layer,with strips arranged perpendicularly between adjacent layers,and the spacing between the strips varied from layer to layer.展开更多
Green transformation is an unavoidable choice for resource-based cities(RBCs)that face resource depletion and environmental pollution.Existing research has focused primarily on specific RBCs,making it challenging to a...Green transformation is an unavoidable choice for resource-based cities(RBCs)that face resource depletion and environmental pollution.Existing research has focused primarily on specific RBCs,making it challenging to apply green transformation strategies universally across cities.The fuzzy set qualitative comparative analysis(fsQCA)is a combination of qualitative and quantitative analyses that can handle multiple concurrent causality problems and determine how different conditions combine into configurations and generate an outcome.Thus,to address this gap,in this study,we established a research framework for green transformation and utilized the fsQCA to examine the configurations of 113 RBCs in China.By incorporating the element of time,this study explored the dynamic evolution of solutions in 2013,2016,and 2019.The main findings indicate that individual elements do not constitute the necessary conditions for improving the green transformation efficiency(GTE),and the systematic combination of multiple conditions is an effective path for realizing the improvement of the GTE in RBCs.Green transformation paths of RBCs exhibit the same destination through different paths.Additionally,the combination of system environment elements and system structure elements is both complementary and alternative.Differences in RBCs have led to various factor combinations and development paths,but there are some similarities in the key elements of the factor combinations at different stages.Economic environment,government support,and technological innovation are key factors that universally enhance the GTE in RBCs.These insights can assist city managers in formulating policies to drive green transformation and contribute to a better theoretical understanding of green transformation paths in RBCs.展开更多
The geological conditions of offshore shallow water delta oil reservoirs were complex, with limited well data and large well spacing. Taking A Oilfield in the Bohai Sea Area, China as an example, the target sand body ...The geological conditions of offshore shallow water delta oil reservoirs were complex, with limited well data and large well spacing. Taking A Oilfield in the Bohai Sea Area, China as an example, the target sand body was formed in a shallow water delta sedimentary environment, with well-developed underwater distributary channels and frequent branching and diversion. The reservoir was strong non-uniformity and uneven plane water cut pressure. To this end, based on the existing work of predecessors, combined with seismic, logging, and production dynamics data, and based on the genesis mechanism of shallow water delta reservoirs, the boundary of composite river channels was identified through seismic facies, and logging facies were used to subdivide them into single river levels within the composite river channels. Then, seismic waveform characteristics were applied to track and characterize the plane distribution of single river channels, guiding the efficient development of offshore shallow water delta oil fields and achieving increased storage and production in Bohai Oilfield, China.展开更多
This study aims to explore the application of digital technology in landscape design,focusing on the research of virtual reality visualization and interactive design in the process of plant configuration.Through an in...This study aims to explore the application of digital technology in landscape design,focusing on the research of virtual reality visualization and interactive design in the process of plant configuration.Through an in-depth analysis of digital technology,the study outlines its important role in landscape design,especially in the application of plant configuration.The current application status of virtual reality technology in landscape design is discussed,as well as how interactive design can enhance user experience and participation.Furthermore,the achievements and challenges of digital technology in landscape design are summarized.Finally,it proposes future research directions and suggestions,aiming to provide new ideas and methods for practice and research in the field of landscape design and promote the further application and development of digital technology in landscape design.展开更多
Geometrical configurations play a crucial role in dual-atom catalysts(DACs)for electrocatalytic applications.Significant progress has been made to design DACs electrocatalysts with various geometri-cal configurations,...Geometrical configurations play a crucial role in dual-atom catalysts(DACs)for electrocatalytic applications.Significant progress has been made to design DACs electrocatalysts with various geometri-cal configurations,but in-depth understanding the relationship between geometrical configurations and metal-metal interaction mechanisms for designing targeted DACs is still required.In this review,the recent progress in engineering of geometrical configurations of DACs is systematically summarized.Based on the polarity of geometrical configuration,DACs can be classified into two different types that are homonuclear and heteronuclear DACs.Furthermore,with regard to the geometrical configurations of the active sites,homonuclear DACs are identified into adjacent and bridged configurations,and heteronuclear DACs can be classified into adjacent,bridged,and separated configurations.Subsequently,metal-metal interactions in DACs with different geometrical configurations are introduced.Additionally,the applications of DACs in different electrocatalytic reactions are discussed,including the oxygen reduction reaction(ORR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and other catalysis.Finally,the future challenges and perspectives for advancements in DACs are high-lighted.This review aims to provide inspiration for the design of highly effcient DACs towards energy relatedapplications.展开更多
Maize(Zea mays L.)-soybean(Glycine max L.Merr.)relay intercropping provides a way to enhance land productivity.However,the late-planted soybean suffers from shading by the maize.After maize harvest,how the recovery gr...Maize(Zea mays L.)-soybean(Glycine max L.Merr.)relay intercropping provides a way to enhance land productivity.However,the late-planted soybean suffers from shading by the maize.After maize harvest,how the recovery growth influences the leaf and nodule traits remains unclear.A three-year field experiment was conducted to evaluate the effects of genotypes,i.e.,supernodulating(nts1007),Nandou 12(ND12),and Guixia 3(GX3),and crop configurations,i.e.,the interspecific row spacing of 45(I45),60(I60),75 cm(I75),and sole soybean(SS),on soybean recovery growth and N fixation.The results showed that intercropping reduced the soybean total leaf area(LA)by reducing both the leaf number(LN)and unit leaflet area(LUA),and it reduced the nodule dry weight(NW)by reducing both the nodule number(NN)and nodule diameter(ND)compared with the SS.The correlation and principal component analysis(PCA)indicated a co-variability of the leaf and nodule traits in response to the genotype and crop configuration interactions.During the recovery growth stages,the compensatory growth promoted soybean growth to reduce the gaps of leaf and nodule traits between intercropping and SS.The relative growth rates of ureide(RGR_U)and nitrogen(RGR_N)accumulation were higher in intercropping than in SS.Intercropping achieved more significant sucrose and starch contents compared with SS.ND12 and GX3 showed more robust compensatory growth than nts1007 in intercropping.Although the recovery growth of relay intercropping soybean improved biomass and nitrogen accumulation,ND12 gained a more significant partial land equivalent ratio(pLER)than GX3.The I60 treatment achieved more robust compensation effects on biomass and N accumulation than the other configurations.Meanwhile,I60 showed a higher nodule sucrose content and greater shoot ureide and N accumulation than SS.Finally,intercropping ND12 with maize using an interspecific row spacing of 60 cm was optimal for both yield advantage and N accumulation.展开更多
Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of g...Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of granular debris during the occurrence of granular debris is essential for precise assessment and effective mitigation of landslide hazards in mountainous terrains. This research aims to investigate the impact of GSD and geometric configurations on sliding and damming properties through laboratory experiments. The geometric configurations were categorized into three categories based on the spatial distribution of maximum volume: located at the front(Type Ⅰ), middle(Type Ⅱ), and rear(Type Ⅲ) of the granular debris. Our experimental findings highlight that the sliding and damming processes primarily depend on the interaction among the geometric configuration, grain size, and GSD in granular debris. Different sliding and damming mechanisms across various geometric configurations induce variability in motion parameters and deposition patterns. For Type Ⅰ configurations, the front debris functions as the critical and primary driving component, with energy dissipation primarily occurring through inter-grain interactions. In contrast, Type Ⅱ configurations feature the middle debris as the dominant driving component, experiencing hindrance from the front debris and propulsion from the rear, leading to complex alterations in sliding motion. Here, energy dissipation arises from a combination of inter-grain and grain-substrate interactions. Lastly, in Type Ⅲ configurations, both the middle and rear debris serve as the main driving components, with the rear sliding debris impeded by the front. In this case, energy dissipation predominantly results from grainsubstrate interaction. Moreover, we have quantitatively demonstrated that the inverse grading in damming deposits, where coarse grain moves upward and fine grain moves downward, is primarily caused by grain sorting due to collisions among the grains and between the grain and the base. The impact of grain on the horizontal channel further aids grain sorting and contributes to inverse grading. The proposed classification of three geometric configurations in our study enhances the understanding of damming properties from the view of mechanism, which provides valuable insights for related study about damming granular debris.展开更多
Field reversed configuration(FRC)is widely considered as an ideal target plasma for magnetoinertial fusion.However,its confinement and stability,both proportional to the radius,will deteriorate inevitably during radia...Field reversed configuration(FRC)is widely considered as an ideal target plasma for magnetoinertial fusion.However,its confinement and stability,both proportional to the radius,will deteriorate inevitably during radial compression.Hence,we propose a new fusion approach based on axial compression of a large-sized FRC.The axial compression can be made by plasma jets or plasmoids converging onto the axial ends of the FRC.The parameter space that can reach the ignition condition while preserving the FRC's overall quality is studied using a numerical model based on different FRC confinement scalings.It is found that ignition is possible for a large FRC that can be achieved with the current FRC formation techniques if compression ratio is greater than 50.A more realistic compression is to combine axial with moderate radial compression,which is also presented and calculated in this work.展开更多
Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catal...Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.展开更多
The promotion of energy efficiency(EE)helps address energy constraints and promote environmental sustainability.This study comprehensively explores the spatiotemporal variations,influencing factors,and configuration p...The promotion of energy efficiency(EE)helps address energy constraints and promote environmental sustainability.This study comprehensively explores the spatiotemporal variations,influencing factors,and configuration promotion paths of EE in 284 Chinese cities during 2003‒2019 using the global super-efficiency minimum distance to strong efficient frontier(G-S-MinDS),exploratory spatial data analysis(ESDA),multiscale geographically weighted regression(MGWR),and fuzzy set qualitative comparative analysis(fsQCA)methods.The findings are:①China’s cities have an annual average EE of 0.658 with a growth rate of 0.53%,showing considerable promotion potential.②Industrial structure optimization,population agglomeration,economic development,and increased green coverage contribute positively,while government intervention and openness hinder China’s urban EE.③Four configurational promotion paths for enhancing China’s urban EE are identified,where among those paths population density is a core condition,while government intervention is not.This study provides valuable insights into substantially improving urban EE,emphasizing the need for targeted policies to address energy and environmental crises in China.展开更多
Based on the geological and geophysical data of Mesozoic oil-gas exploration in the sea area of Bohai Bay Basin and the discovered high-yield volcanic oil and gas wells since 2019,this paper methodically summarizes th...Based on the geological and geophysical data of Mesozoic oil-gas exploration in the sea area of Bohai Bay Basin and the discovered high-yield volcanic oil and gas wells since 2019,this paper methodically summarizes the formation conditions of large-and medium-sized Cretaceous volcanic oil and gas reservoirs in the Bohai Sea.Research shows that the Mesozoic large intermediate-felsic lava and intermediate-felsic composite volcanic edifices in the Bohai Sea are the material basis for the formation of large-scale volcanic reservoirs.The upper subfacies of effusive facies and cryptoexplosive breccia subfacies of volcanic conduit facies of volcanic vent-proximal facies belts are favorable for large-scale volcanic reservoir formation.Two types of efficient reservoirs,characterized by high porosity and medium to low permeability,as well as medium porosity and medium to low permeability,are the core of the formation of large-and medium-sized volcanic reservoirs.The reservoir with high porosity and medium to low permeability is formed by intermediate-felsic vesicular lava or the cryptoexplosive breccia superimposed by intensive dissolution.The reservoir with medium porosity and medium to low permeability is formed by intense tectonism superimposed by fluid dissolution.Weathering and tectonic transformation are main formation mechanisms for large and medium-sized volcanic reservoirs in the study area.The low-source“source-reservoir draping type”is the optimum source-reservoir configuration relationship for large-and medium-sized volcanic reservoirs.There exists favorable volcanic facies,efficient reservoirs and source-reservoir draping configuration relationship on the periphery of Bozhong Sag,and the large intermediate-felsic lava and intermediate-felsic composite volcanic edifices close to strike-slip faults and their branch faults are the main directions of future exploration.展开更多
With the widespread application of integrated modular aviation(IMA)electronic systems,the requirements of IMA characteristic analysis and configuration generation have also improved significantly."Configuration a...With the widespread application of integrated modular aviation(IMA)electronic systems,the requirements of IMA characteristic analysis and configuration generation have also improved significantly."Configuration and design system based on AADL models(real-time,reliability,interactive complexity,and schedulability)analysis of the AADL model"mainly get through key characteristic analysis for optimization,combined with input of component parameter information and constraint information,assist designers in generating system configuration information,and form a comprehensive modular avionics system resource configuration strategy generation platform.Also,the tool can generate configuration plans for avionics system software and hardware physical architecture configuration.The analysis of the avionics system model mainly involves designers inputting the existing system model architecture for multi characteristic analysis,it can realize the multi-character analysis based on software intensive system architecture models for software dense systems.Inter-complexity and schedulability analysis,and according to characteristic constraint analysis、system model assessment parameters and system architecture constraint parameters to generate configuration scheme information that meets the requirements.The system can meet domestic and foreign software-intensive systems and meet its quality requirements.展开更多
The rapid growth of the education industry and private education groups has brought the high-quality development of listed private education companies into focus for both the educational sector and the capital market....The rapid growth of the education industry and private education groups has brought the high-quality development of listed private education companies into focus for both the educational sector and the capital market.This study employs the fuzzy-set qualitative comparative analysis(fsQCA)method to explore pathways to high-quality development for these companies.Necessity analysis confirms that no single factor guarantees a company’s success,highlighting the importance of multi-factor interactions.Three main paths to high-quality development are identified:human resource optimization,precise market positioning,and comprehensive advantage.Conversely,four development paths for non-high-level companies are identified:dual insufficiency in resources and market,high turnover and over-investment,scale expansion with resource mismatch,and inadequate human resource development.The findings indicate that optimal allocation of educational resources,precise market positioning,rational resource allocation,and staff training are crucial for achieving high-quality development.Robustness tests,which raise the consistency threshold,verify the reliability and stability of the results.These findings provide a reference for policymakers,investors,and managers in the education industry.展开更多
This study investigates the breakdown voltage characteristics in sulfur hexafluoride(SF6)circuit breakers,employing a novel approach that integrates both experimental investigations and finite element simulations.Util...This study investigates the breakdown voltage characteristics in sulfur hexafluoride(SF6)circuit breakers,employing a novel approach that integrates both experimental investigations and finite element simulations.Utilizing a sphere-sphere electrode configuration,we meticulously measured the relationship between breakdown voltage and electrode gap distances ranging from 1 cm to 4.5 cm.Subsequent simulations,conducted using COMSOL Multiphysics,mirrored the experimental setup to validate the model’s accuracy through a comparison of the breakdown voltage-electrode gap distance curves.The simulation results not only aligned closely with the experimental data but also allowed the extraction of detailed electric field strength,electric potential contours,and electric current flow curves at the breakdown voltage for gap distances extending from 1 to 4.5 cm.Extending the analysis,the study explored the electric field and potential distribution at a constant voltage of 72.5 kV for gap distances between 1 to 10 cm,identifying the maximum electric field strength.A comprehensive comparison of five different electrode configurations(sphere-sphere,sphere-rod,sphere-plane,rod-plane,rod-rod)at 72.5 kV and a gap distance of 1.84 cm underscored the significant influence of electrode geometry on the breakdown process.Moreover,the research contrasts the breakdown voltage in SF6 with that in air,emphasizing SF6’s superior insulating properties.This investigation not only elucidates the intricate dynamics of electrical breakdown in SF6 circuit breakers but also contributes valuable insights into the optimal electrode configurations and the potential for alternative insulating gases,steering future advancements in high-voltage circuit breaker technology.展开更多
Deployable mechanism with preferable deployable performance,strong expansibility,and lightweight has attracted much attention because of their potential in aerospace.A basic deployable pyramid unit with good deployabi...Deployable mechanism with preferable deployable performance,strong expansibility,and lightweight has attracted much attention because of their potential in aerospace.A basic deployable pyramid unit with good deployability and expandability is proposed to construct a sizeable deployable mechanism.Firstly,the basic unit folding principle and expansion method is proposed.The configuration synthesis method of adding constraint chains of spatial closed-loop mechanism is used to synthesize the basic unit.Then,the degree of freedom of the basic unit is analyzed using the screw theory and the link dismantling method.Next,the three-dimensional models of the pyramid unit,expansion unit,and array unit are established,and the folding motion simulation analysis is carried out.Based on the number of components,weight reduction rate,and deployable rate,the performance characteristics of the three types of mechanisms are described in detail.Finally,prototypes of the pyramid unit,combination unit,and expansion unit are developed to verify further the correctness of the configuration synthesis based on the pyramid.The proposed deployable mechanism provides aference for the design and application of antennas with a large aperture,high deployable rate,and lightweight.It has a good application prospect in the aerospace field.展开更多
Unified power quality conditioner(UPQC)with energy storage is commonly based on conventional capacity configuration strategy with power angle control.It has problems such as phase jumping before and after compensation...Unified power quality conditioner(UPQC)with energy storage is commonly based on conventional capacity configuration strategy with power angle control.It has problems such as phase jumping before and after compensation.DC-link cannot continuously emit active power externally.Therefore,this paper presents the compensation strategy of full load voltage magnitude and phase in capacity configuration of UPQC.The topology of UPQC is integrated a series active power filter(SAPF),a shunt active power filter(PAPF)and a photovoltaic-battery energy storage system(PV-BESS).The principle of full load voltage compensation is analyzed based on the PV-BESS-UPQC topology.Themagnitude constant of load voltage ismaintained by controlling the appropriate shunt compensation current.Then the UPQC capacity configuration is carried out using the full load voltage compensation strategy.The compensation capacity of UPQC series and shunt units are reduced.Finally,the simulation results show that the proposed compensation strategy reduces the capacity configuration by 5.11 kVA(36.4%)compared to the conventional compensation strategy.The proposed strategy can achieve full compensation of the load voltage,which can effectively reduce the capacity allocation and improve the economy of UPQC.It also has the PV-BESS units’ability of providing active power and can stabilize the DC-link voltage.展开更多
Because of the randomness of wind power and photovoltaic(PV)output of new energy bases,the problem of peak regulation capability and voltage stability of ultra-high voltage direct current(UHVDC)transmission lines,we p...Because of the randomness of wind power and photovoltaic(PV)output of new energy bases,the problem of peak regulation capability and voltage stability of ultra-high voltage direct current(UHVDC)transmission lines,we proposed an optimum allocation method of installed capacity of the solar-thermal power station based on chance constrained programming in this work.Firstly,we established the uncertainty model of wind power and PV based on the chance constrained planning theory.Then we used the K-medoids clusteringmethod to cluster the scenarios considering the actual operation scenarios throughout the year.Secondly,we established the optimal configuration model based on the objective function of the strongest transient voltage stability and the lowest overall cost of operation.Finally,by quantitative analysis of actual wind power and photovoltaic new energy base,this work verified the feasibility of the proposed method.As a result of the simulations,we found that using the optimal configuration method of solar-thermal power stations could ensure an accurate allocation of installed capacity.When the installed capacity of the solar-thermal power station is 1×106 kW,the transient voltage recovery index(TVRI)is 0.359,which has a strong voltage support capacity for the system.Based on the results of this work,the optimal configuration of the installed capacity of the solar-thermal power plant can improve peak shaving performance,transient voltage support capability,and new energy consumption while satisfying the Direct Current(DC)outgoing transmission premise.展开更多
The effects of adjacent metal layers and space between metal lines on the temperature rise of multilevel ULSI interconnect lines are investigated by modeling a three-layer interconnect. The heat dissipation of various...The effects of adjacent metal layers and space between metal lines on the temperature rise of multilevel ULSI interconnect lines are investigated by modeling a three-layer interconnect. The heat dissipation of various metallization technologies concerning the metal and low-k dielectric employment is simulated in detail. The Joule heat generated in the interconnect is transferred mainly through the metal lines in each metal layer and through the path with the smallest thermal resistance in each Ield layer. The temperature rises of Al metallization are approximately pAl/pCu times higher than those of Cu metallization under the same conditions. In addition, a thermal problem in 0.13μm globe interconnects is studied for the worst case, in which there are no metal lines in the lower interconnect layers. Several types of dummy metal heat sinks are investigated and compared with regard to thermal efficiency,influence on parasitic capacitance,and optimal application by combined thermal and electrical simula- tion.展开更多
基金supported by the Joint Research Fund in Smart Grid(U23B20120)under cooperative agreement between the National Natural Science Foundation of China and State Grid Corporation of China。
文摘Based on the complementary advantages of Line Commutated Converter(LCC)and Modular Multilevel Converter(MMC)in power grid applications,there are two types of hybrid DC system topologies:one is the parallel connection of LCC converter stations and MMC converter stations,and the other is the series connection of LCC and MMC converter stations within a single station.The hybrid DC transmission system faces broad application prospects and development potential in large-scale clean energy integration across regions and the construction of a new power system dominated by new energy sources in China.This paper first analyzes the system forms and topological characteristics of hybrid DC transmission,introducing the forms and topological characteristics of converter-level hybrid DC transmission systems and system-level hybrid DC transmission systems.Next,it analyzes the operating characteristics of LCC and MMC inverter-level hybrid DC transmission systems,provides insights into the transient stability of hybrid DC transmission systems,and typical fault ride-through control strategies.Finally,it summarizes the networking characteristics of the LCC-MMC series within the converter station hybrid DC transmission system,studies the transient characteristics and fault ridethrough control strategies under different fault types for the LCC-MMC series in the receiving-end converter station,and investigates the transient characteristics and fault ride-through control strategies under different fault types for the LCC-MMC series in the sending-end converter station.
基金supported by the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20220649)the Natural Science Foundation of the Jiangsu Higher Education Institutions(Grant No.23KJB460010)+1 种基金the Key R&D Program of Jiangsu Province(Grant No.BE2022062)Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.SJCX23_2143).
文摘Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological features.Firstly,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain synthesis.Secondly,the screw theory is employed to analyze the degree of freedom(DoF)of the capture mechanism.Then,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried out.Combined with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried out.Furthermore,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are analyzed.Finally,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is completed.The work provides technical reserves for the research and development of AUV capture special equipment.
文摘Fixed-bed reactors are generally considered the optimal choice for numerous multi-phase catalytic reactions due to their excellent performance and stability.However,conventional fixed beds often encounter challenges related to inadequate mass transfer and a high pressure drop caused by the non-uniform void fraction distribution.To enhance the overall performance of fixed beds,the impact of different packing configurations on performance was investigated.Experimental and simulation methods were used to investigate the fluid flow and mass transfer performances of various packed beds under different flow rates.It was found that structured beds exhibited a significantly lower pressure drop per unit length than conventional packed beds.Furthermore,the packing configurations had a critical role in improving the overall performance of fixed beds.Specifically,structured packed beds,particularly the H-2 packing configuration,effectively reduced the pressure drop per unit length and improved the mass transfer efficiency.The H-2 packing configuration consisted of two parallel strips of particles in each layer,with strips arranged perpendicularly between adjacent layers,and the spacing between the strips varied from layer to layer.
基金supported by the Chongqing Social Science Planning Fund,China(2023BS034)the Science and Technology Project of Chongqing Jiaotong University,China(F1230069).
文摘Green transformation is an unavoidable choice for resource-based cities(RBCs)that face resource depletion and environmental pollution.Existing research has focused primarily on specific RBCs,making it challenging to apply green transformation strategies universally across cities.The fuzzy set qualitative comparative analysis(fsQCA)is a combination of qualitative and quantitative analyses that can handle multiple concurrent causality problems and determine how different conditions combine into configurations and generate an outcome.Thus,to address this gap,in this study,we established a research framework for green transformation and utilized the fsQCA to examine the configurations of 113 RBCs in China.By incorporating the element of time,this study explored the dynamic evolution of solutions in 2013,2016,and 2019.The main findings indicate that individual elements do not constitute the necessary conditions for improving the green transformation efficiency(GTE),and the systematic combination of multiple conditions is an effective path for realizing the improvement of the GTE in RBCs.Green transformation paths of RBCs exhibit the same destination through different paths.Additionally,the combination of system environment elements and system structure elements is both complementary and alternative.Differences in RBCs have led to various factor combinations and development paths,but there are some similarities in the key elements of the factor combinations at different stages.Economic environment,government support,and technological innovation are key factors that universally enhance the GTE in RBCs.These insights can assist city managers in formulating policies to drive green transformation and contribute to a better theoretical understanding of green transformation paths in RBCs.
文摘The geological conditions of offshore shallow water delta oil reservoirs were complex, with limited well data and large well spacing. Taking A Oilfield in the Bohai Sea Area, China as an example, the target sand body was formed in a shallow water delta sedimentary environment, with well-developed underwater distributary channels and frequent branching and diversion. The reservoir was strong non-uniformity and uneven plane water cut pressure. To this end, based on the existing work of predecessors, combined with seismic, logging, and production dynamics data, and based on the genesis mechanism of shallow water delta reservoirs, the boundary of composite river channels was identified through seismic facies, and logging facies were used to subdivide them into single river levels within the composite river channels. Then, seismic waveform characteristics were applied to track and characterize the plane distribution of single river channels, guiding the efficient development of offshore shallow water delta oil fields and achieving increased storage and production in Bohai Oilfield, China.
基金2023 Campus Scientific Research Fund of Chongqing Institute of Engineering(Project number:2023xsky03)2023 Education and Teaching Reform Research Project of Chongqing Institute of Engineering(Project number:JY2023214)2023 First-class Curriculum Construction Project of Chongqing Institute of Engineering(Project number:KC20230103)。
文摘This study aims to explore the application of digital technology in landscape design,focusing on the research of virtual reality visualization and interactive design in the process of plant configuration.Through an in-depth analysis of digital technology,the study outlines its important role in landscape design,especially in the application of plant configuration.The current application status of virtual reality technology in landscape design is discussed,as well as how interactive design can enhance user experience and participation.Furthermore,the achievements and challenges of digital technology in landscape design are summarized.Finally,it proposes future research directions and suggestions,aiming to provide new ideas and methods for practice and research in the field of landscape design and promote the further application and development of digital technology in landscape design.
基金supported by the Natural Science Foundation of China (22179062,52125202,and U2004209)the Natural Science Foundation of Jiangsu Province (BK20230035)+1 种基金the Fundamental Research Funds for the Central Universities (30922010303)the Intergovernmental Cooperation Projects in the National Key Research and Development Plan of the Ministry of Science and Technology of PRC (2022YFE0196800)
文摘Geometrical configurations play a crucial role in dual-atom catalysts(DACs)for electrocatalytic applications.Significant progress has been made to design DACs electrocatalysts with various geometri-cal configurations,but in-depth understanding the relationship between geometrical configurations and metal-metal interaction mechanisms for designing targeted DACs is still required.In this review,the recent progress in engineering of geometrical configurations of DACs is systematically summarized.Based on the polarity of geometrical configuration,DACs can be classified into two different types that are homonuclear and heteronuclear DACs.Furthermore,with regard to the geometrical configurations of the active sites,homonuclear DACs are identified into adjacent and bridged configurations,and heteronuclear DACs can be classified into adjacent,bridged,and separated configurations.Subsequently,metal-metal interactions in DACs with different geometrical configurations are introduced.Additionally,the applications of DACs in different electrocatalytic reactions are discussed,including the oxygen reduction reaction(ORR),oxygen evolution reaction(OER),hydrogen evolution reaction(HER),and other catalysis.Finally,the future challenges and perspectives for advancements in DACs are high-lighted.This review aims to provide inspiration for the design of highly effcient DACs towards energy relatedapplications.
基金supported by the China Agriculture Research System of MOF and MARA(Soybean,CARS04-PS20)the National Natural Science Foundation of China(3187101212 and 31671625).
文摘Maize(Zea mays L.)-soybean(Glycine max L.Merr.)relay intercropping provides a way to enhance land productivity.However,the late-planted soybean suffers from shading by the maize.After maize harvest,how the recovery growth influences the leaf and nodule traits remains unclear.A three-year field experiment was conducted to evaluate the effects of genotypes,i.e.,supernodulating(nts1007),Nandou 12(ND12),and Guixia 3(GX3),and crop configurations,i.e.,the interspecific row spacing of 45(I45),60(I60),75 cm(I75),and sole soybean(SS),on soybean recovery growth and N fixation.The results showed that intercropping reduced the soybean total leaf area(LA)by reducing both the leaf number(LN)and unit leaflet area(LUA),and it reduced the nodule dry weight(NW)by reducing both the nodule number(NN)and nodule diameter(ND)compared with the SS.The correlation and principal component analysis(PCA)indicated a co-variability of the leaf and nodule traits in response to the genotype and crop configuration interactions.During the recovery growth stages,the compensatory growth promoted soybean growth to reduce the gaps of leaf and nodule traits between intercropping and SS.The relative growth rates of ureide(RGR_U)and nitrogen(RGR_N)accumulation were higher in intercropping than in SS.Intercropping achieved more significant sucrose and starch contents compared with SS.ND12 and GX3 showed more robust compensatory growth than nts1007 in intercropping.Although the recovery growth of relay intercropping soybean improved biomass and nitrogen accumulation,ND12 gained a more significant partial land equivalent ratio(pLER)than GX3.The I60 treatment achieved more robust compensation effects on biomass and N accumulation than the other configurations.Meanwhile,I60 showed a higher nodule sucrose content and greater shoot ureide and N accumulation than SS.Finally,intercropping ND12 with maize using an interspecific row spacing of 60 cm was optimal for both yield advantage and N accumulation.
基金support of the National Natural Science Foundation of China(U20A20111,42107189).
文摘Granular debris plays a significant role in determining damming deposit characteristics. An indepth understanding of how variations in grain size distribution(GSD) and geometric configurations impact the behavior of granular debris during the occurrence of granular debris is essential for precise assessment and effective mitigation of landslide hazards in mountainous terrains. This research aims to investigate the impact of GSD and geometric configurations on sliding and damming properties through laboratory experiments. The geometric configurations were categorized into three categories based on the spatial distribution of maximum volume: located at the front(Type Ⅰ), middle(Type Ⅱ), and rear(Type Ⅲ) of the granular debris. Our experimental findings highlight that the sliding and damming processes primarily depend on the interaction among the geometric configuration, grain size, and GSD in granular debris. Different sliding and damming mechanisms across various geometric configurations induce variability in motion parameters and deposition patterns. For Type Ⅰ configurations, the front debris functions as the critical and primary driving component, with energy dissipation primarily occurring through inter-grain interactions. In contrast, Type Ⅱ configurations feature the middle debris as the dominant driving component, experiencing hindrance from the front debris and propulsion from the rear, leading to complex alterations in sliding motion. Here, energy dissipation arises from a combination of inter-grain and grain-substrate interactions. Lastly, in Type Ⅲ configurations, both the middle and rear debris serve as the main driving components, with the rear sliding debris impeded by the front. In this case, energy dissipation predominantly results from grainsubstrate interaction. Moreover, we have quantitatively demonstrated that the inverse grading in damming deposits, where coarse grain moves upward and fine grain moves downward, is primarily caused by grain sorting due to collisions among the grains and between the grain and the base. The impact of grain on the horizontal channel further aids grain sorting and contributes to inverse grading. The proposed classification of three geometric configurations in our study enhances the understanding of damming properties from the view of mechanism, which provides valuable insights for related study about damming granular debris.
基金supported by National Natural Science Foundation of China(No.12175226)。
文摘Field reversed configuration(FRC)is widely considered as an ideal target plasma for magnetoinertial fusion.However,its confinement and stability,both proportional to the radius,will deteriorate inevitably during radial compression.Hence,we propose a new fusion approach based on axial compression of a large-sized FRC.The axial compression can be made by plasma jets or plasmoids converging onto the axial ends of the FRC.The parameter space that can reach the ignition condition while preserving the FRC's overall quality is studied using a numerical model based on different FRC confinement scalings.It is found that ignition is possible for a large FRC that can be achieved with the current FRC formation techniques if compression ratio is greater than 50.A more realistic compression is to combine axial with moderate radial compression,which is also presented and calculated in this work.
基金the National Natural Science Foundation of China(U21A20286,22206054 and 21805069)Natural Science Foundation of Hubei(2021CFB094)the Fundamental Research Funds for the Central China Normal University(CCNU)for financial support。
文摘Spinel cobalt oxide(Co_(3)O_(4)),consisting of tetrahedral Co^(2+)(CoTd)and octahedral Co^(3+)(CoOh),is considered as promising earth-abundant electrocatalyst for chlorine evolution reaction(CER).Identifying the catalytic contribution of geometric Co site in the electrocatalytic CER plays a pivotal role to precisely modulate electronic configuration of active Co sites to boost CER.Herein,combining density functional theory calculations and experiment results assisted with operando analysis,we found that the Co_(Oh) site acts as the main active site for CER in spinel Co_(3)O_(4),which shows better Cl^(-)adsorption and more moderate intermediate adsorption toward CER than CoTd site,and does not undergo redox transition under CER condition at applied potentials.Guided by above findings,the oxygen vacancies were further introduced into the Co_(3)O_(4) to precisely manipulate the electronic configuration of Co_(Oh) to boost Cl^(-)adsorption and optimize the reaction path of CER and thus to enhance the intrinsic CER activity significantly.Our work figures out the importance of geometric configuration dependent CER activity,shedding light on the rational design of advanced electrocatalysts from geometric configuration optimization at the atomic level.
基金the financial support provided by the National Natural Science Foundation of China[Grant No.72373138 and 71973131]Major Project of National Social Science Foundation of China[Grant No.19VHQ002].
文摘The promotion of energy efficiency(EE)helps address energy constraints and promote environmental sustainability.This study comprehensively explores the spatiotemporal variations,influencing factors,and configuration promotion paths of EE in 284 Chinese cities during 2003‒2019 using the global super-efficiency minimum distance to strong efficient frontier(G-S-MinDS),exploratory spatial data analysis(ESDA),multiscale geographically weighted regression(MGWR),and fuzzy set qualitative comparative analysis(fsQCA)methods.The findings are:①China’s cities have an annual average EE of 0.658 with a growth rate of 0.53%,showing considerable promotion potential.②Industrial structure optimization,population agglomeration,economic development,and increased green coverage contribute positively,while government intervention and openness hinder China’s urban EE.③Four configurational promotion paths for enhancing China’s urban EE are identified,where among those paths population density is a core condition,while government intervention is not.This study provides valuable insights into substantially improving urban EE,emphasizing the need for targeted policies to address energy and environmental crises in China.
基金Supported by the China National Offshore Oil Corporation Limited Project(2021-KT-YXKY-03)。
文摘Based on the geological and geophysical data of Mesozoic oil-gas exploration in the sea area of Bohai Bay Basin and the discovered high-yield volcanic oil and gas wells since 2019,this paper methodically summarizes the formation conditions of large-and medium-sized Cretaceous volcanic oil and gas reservoirs in the Bohai Sea.Research shows that the Mesozoic large intermediate-felsic lava and intermediate-felsic composite volcanic edifices in the Bohai Sea are the material basis for the formation of large-scale volcanic reservoirs.The upper subfacies of effusive facies and cryptoexplosive breccia subfacies of volcanic conduit facies of volcanic vent-proximal facies belts are favorable for large-scale volcanic reservoir formation.Two types of efficient reservoirs,characterized by high porosity and medium to low permeability,as well as medium porosity and medium to low permeability,are the core of the formation of large-and medium-sized volcanic reservoirs.The reservoir with high porosity and medium to low permeability is formed by intermediate-felsic vesicular lava or the cryptoexplosive breccia superimposed by intensive dissolution.The reservoir with medium porosity and medium to low permeability is formed by intense tectonism superimposed by fluid dissolution.Weathering and tectonic transformation are main formation mechanisms for large and medium-sized volcanic reservoirs in the study area.The low-source“source-reservoir draping type”is the optimum source-reservoir configuration relationship for large-and medium-sized volcanic reservoirs.There exists favorable volcanic facies,efficient reservoirs and source-reservoir draping configuration relationship on the periphery of Bozhong Sag,and the large intermediate-felsic lava and intermediate-felsic composite volcanic edifices close to strike-slip faults and their branch faults are the main directions of future exploration.
文摘With the widespread application of integrated modular aviation(IMA)electronic systems,the requirements of IMA characteristic analysis and configuration generation have also improved significantly."Configuration and design system based on AADL models(real-time,reliability,interactive complexity,and schedulability)analysis of the AADL model"mainly get through key characteristic analysis for optimization,combined with input of component parameter information and constraint information,assist designers in generating system configuration information,and form a comprehensive modular avionics system resource configuration strategy generation platform.Also,the tool can generate configuration plans for avionics system software and hardware physical architecture configuration.The analysis of the avionics system model mainly involves designers inputting the existing system model architecture for multi characteristic analysis,it can realize the multi-character analysis based on software intensive system architecture models for software dense systems.Inter-complexity and schedulability analysis,and according to characteristic constraint analysis、system model assessment parameters and system architecture constraint parameters to generate configuration scheme information that meets the requirements.The system can meet domestic and foreign software-intensive systems and meet its quality requirements.
基金2024 Guangdong Provincial Private Colleges and Universities Research Project“Research on the Path of High-Quality Development of Listed Companies in Private Education Groups:An Analysis of Complex Factor Groups”(GMG2024023)。
文摘The rapid growth of the education industry and private education groups has brought the high-quality development of listed private education companies into focus for both the educational sector and the capital market.This study employs the fuzzy-set qualitative comparative analysis(fsQCA)method to explore pathways to high-quality development for these companies.Necessity analysis confirms that no single factor guarantees a company’s success,highlighting the importance of multi-factor interactions.Three main paths to high-quality development are identified:human resource optimization,precise market positioning,and comprehensive advantage.Conversely,four development paths for non-high-level companies are identified:dual insufficiency in resources and market,high turnover and over-investment,scale expansion with resource mismatch,and inadequate human resource development.The findings indicate that optimal allocation of educational resources,precise market positioning,rational resource allocation,and staff training are crucial for achieving high-quality development.Robustness tests,which raise the consistency threshold,verify the reliability and stability of the results.These findings provide a reference for policymakers,investors,and managers in the education industry.
基金Ningbo Science and Technology Plan Project(Grant No.2023Z043)。
文摘This study investigates the breakdown voltage characteristics in sulfur hexafluoride(SF6)circuit breakers,employing a novel approach that integrates both experimental investigations and finite element simulations.Utilizing a sphere-sphere electrode configuration,we meticulously measured the relationship between breakdown voltage and electrode gap distances ranging from 1 cm to 4.5 cm.Subsequent simulations,conducted using COMSOL Multiphysics,mirrored the experimental setup to validate the model’s accuracy through a comparison of the breakdown voltage-electrode gap distance curves.The simulation results not only aligned closely with the experimental data but also allowed the extraction of detailed electric field strength,electric potential contours,and electric current flow curves at the breakdown voltage for gap distances extending from 1 to 4.5 cm.Extending the analysis,the study explored the electric field and potential distribution at a constant voltage of 72.5 kV for gap distances between 1 to 10 cm,identifying the maximum electric field strength.A comprehensive comparison of five different electrode configurations(sphere-sphere,sphere-rod,sphere-plane,rod-plane,rod-rod)at 72.5 kV and a gap distance of 1.84 cm underscored the significant influence of electrode geometry on the breakdown process.Moreover,the research contrasts the breakdown voltage in SF6 with that in air,emphasizing SF6’s superior insulating properties.This investigation not only elucidates the intricate dynamics of electrical breakdown in SF6 circuit breakers but also contributes valuable insights into the optimal electrode configurations and the potential for alternative insulating gases,steering future advancements in high-voltage circuit breaker technology.
基金Supported by National Natural Science Foundation of China(Grant No.52075467)Jiangsu Provincial Natural Science Foundation of China(Grant No.BK20220649)+1 种基金Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant No.23KJB460010)Jiangsu Provincial Key R&D Project(Grant No.BE2022062).
文摘Deployable mechanism with preferable deployable performance,strong expansibility,and lightweight has attracted much attention because of their potential in aerospace.A basic deployable pyramid unit with good deployability and expandability is proposed to construct a sizeable deployable mechanism.Firstly,the basic unit folding principle and expansion method is proposed.The configuration synthesis method of adding constraint chains of spatial closed-loop mechanism is used to synthesize the basic unit.Then,the degree of freedom of the basic unit is analyzed using the screw theory and the link dismantling method.Next,the three-dimensional models of the pyramid unit,expansion unit,and array unit are established,and the folding motion simulation analysis is carried out.Based on the number of components,weight reduction rate,and deployable rate,the performance characteristics of the three types of mechanisms are described in detail.Finally,prototypes of the pyramid unit,combination unit,and expansion unit are developed to verify further the correctness of the configuration synthesis based on the pyramid.The proposed deployable mechanism provides aference for the design and application of antennas with a large aperture,high deployable rate,and lightweight.It has a good application prospect in the aerospace field.
基金Supported by Open Project of Jiangsu Key Laboratory of Power Transmission&Distribution Equipment Technology(2021JSSPD12)Supported by Talent Projects of Jiangsu University of Technology(KYY20018)Supported by Graduate Practice Innovation Program of Jiangsu University of Technology(XSJCX21_32).
文摘Unified power quality conditioner(UPQC)with energy storage is commonly based on conventional capacity configuration strategy with power angle control.It has problems such as phase jumping before and after compensation.DC-link cannot continuously emit active power externally.Therefore,this paper presents the compensation strategy of full load voltage magnitude and phase in capacity configuration of UPQC.The topology of UPQC is integrated a series active power filter(SAPF),a shunt active power filter(PAPF)and a photovoltaic-battery energy storage system(PV-BESS).The principle of full load voltage compensation is analyzed based on the PV-BESS-UPQC topology.Themagnitude constant of load voltage ismaintained by controlling the appropriate shunt compensation current.Then the UPQC capacity configuration is carried out using the full load voltage compensation strategy.The compensation capacity of UPQC series and shunt units are reduced.Finally,the simulation results show that the proposed compensation strategy reduces the capacity configuration by 5.11 kVA(36.4%)compared to the conventional compensation strategy.The proposed strategy can achieve full compensation of the load voltage,which can effectively reduce the capacity allocation and improve the economy of UPQC.It also has the PV-BESS units’ability of providing active power and can stabilize the DC-link voltage.
基金funded by Major Science and Technology Projects in Gansu Province(19ZD2GA003).
文摘Because of the randomness of wind power and photovoltaic(PV)output of new energy bases,the problem of peak regulation capability and voltage stability of ultra-high voltage direct current(UHVDC)transmission lines,we proposed an optimum allocation method of installed capacity of the solar-thermal power station based on chance constrained programming in this work.Firstly,we established the uncertainty model of wind power and PV based on the chance constrained planning theory.Then we used the K-medoids clusteringmethod to cluster the scenarios considering the actual operation scenarios throughout the year.Secondly,we established the optimal configuration model based on the objective function of the strongest transient voltage stability and the lowest overall cost of operation.Finally,by quantitative analysis of actual wind power and photovoltaic new energy base,this work verified the feasibility of the proposed method.As a result of the simulations,we found that using the optimal configuration method of solar-thermal power stations could ensure an accurate allocation of installed capacity.When the installed capacity of the solar-thermal power station is 1×106 kW,the transient voltage recovery index(TVRI)is 0.359,which has a strong voltage support capacity for the system.Based on the results of this work,the optimal configuration of the installed capacity of the solar-thermal power plant can improve peak shaving performance,transient voltage support capability,and new energy consumption while satisfying the Direct Current(DC)outgoing transmission premise.
文摘The effects of adjacent metal layers and space between metal lines on the temperature rise of multilevel ULSI interconnect lines are investigated by modeling a three-layer interconnect. The heat dissipation of various metallization technologies concerning the metal and low-k dielectric employment is simulated in detail. The Joule heat generated in the interconnect is transferred mainly through the metal lines in each metal layer and through the path with the smallest thermal resistance in each Ield layer. The temperature rises of Al metallization are approximately pAl/pCu times higher than those of Cu metallization under the same conditions. In addition, a thermal problem in 0.13μm globe interconnects is studied for the worst case, in which there are no metal lines in the lower interconnect layers. Several types of dummy metal heat sinks are investigated and compared with regard to thermal efficiency,influence on parasitic capacitance,and optimal application by combined thermal and electrical simula- tion.