Spiral pile foundations,as a promising type of foundation,are of significant importance for the development of offshore wind energy,particularly as it moves toward deeper waters.This study conducted a physical experim...Spiral pile foundations,as a promising type of foundation,are of significant importance for the development of offshore wind energy,particularly as it moves toward deeper waters.This study conducted a physical experiment on a three-spiral-pile jacket foundation under deep-buried sandy soil conditions.During the experiment,horizontal displacement was applied to the structure to thoroughly investigate the bearing characteristics of the three-spiral-pile jacket foundation.This study also focused on analyzing the bearing mechanisms of conventional piles compared with spiral piles with different numbers of blades.Three different working conditions were set up and compared,and key data,such as the horizontal bearing capacity,pile shaft axial force,and spiral blade soil pressure,were measured and analyzed.The results show the distinct impacts of the spiral blades on the compressed and tensioned sides of the foundation.Specifically,on the compressed side,the spiral blades effectively enhance the restraint of the soil on the pile foundation,whereas on the tensioned side,an excessive number of spiral blades can negatively affect the structural tensile performance to some extent.This study also emphasizes that the addition of blades to the side of a single pile is the most effective method for increasing the bearing capacity of the foundation.This research aims to provide design insights into improving the bearing capacity of the foundation.展开更多
Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significan...Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significant gap in detailed and consistent data on 3D building space structures with global coverage due to the challenges inherent in the data collection and model calibration processes.In this study,we constructed a global urban structure(GUS-3D)dataset,including building volume,height,and footprint information,at a 500 m spatial resolution using extensive satellite observation products and numerous reference building samples.Our analysis indicated that the total volume of buildings worldwide in2015 exceeded 1×10^(12)m^(3).Over the 1985 to 2015 period,we observed a slight increase in the magnitude of 3D building volume growth(i.e.,it increased from 166.02 km3 during the 1985–2000 period to 175.08km3 during the 2000–2015 period),while the expansion magnitudes of the two-dimensional(2D)building footprint(22.51×10^(3) vs 13.29×10^(3)km^(2))and urban extent(157×10^(3) vs 133.8×10^(3)km^(2))notably decreased.This trend highlights the significant increase in intensive vertical utilization of urban land.Furthermore,we identified significant heterogeneity in building space provision and inequality across cities worldwide.This inequality is particularly pronounced in many populous Asian cities,which has been overlooked in previous studies on economic inequality.The GUS-3D dataset shows great potential to deepen our understanding of the urban environment and creates new horizons for numerous 3D urban studies.展开更多
Thermal barrier coatings(TBCs)are extensively utilized in aero-engines and heavy-duty gas turbines due to their outstanding properties,including low thermal conductivity,corrosion,high-temperature oxidation,and wear r...Thermal barrier coatings(TBCs)are extensively utilized in aero-engines and heavy-duty gas turbines due to their outstanding properties,including low thermal conductivity,corrosion,high-temperature oxidation,and wear resistance.The rising thrust-to-weight ratio and service temperature in engine hot sections have presented a significant challenge in TBC's materials,structure,and preparation process;it is one of the current research hotspots in the aviation field.This paper reviews the recent advancement in turbine blade TBCs.It focuses on the TBC's structure,deposition mechanism and the key performance evaluation indexes for TBCs applied to turbine blades.Finally,the future research field of TBCs for turbine blades is also be prospected.展开更多
To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D lea...To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance law.First,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact time.Next,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the time-to-go.Then,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy consumption.Moreover,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering applications.Finally,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law.展开更多
This paper presents a numerical study of the flow topologies of three-dimensional （3D） flows in a high pressure compressor stator blade row without and with boundary layer aspiration on the hub wall. The stator blad...This paper presents a numerical study of the flow topologies of three-dimensional （3D） flows in a high pressure compressor stator blade row without and with boundary layer aspiration on the hub wall. The stator blade is representative of the first stage operating under transonic inlet conditions and the blade design encourages development of highly complex 3D flows. The blade has a small tip clearance. The computational fluid dynamics （CFD） studies show progressive increase of hub corner stall with the increase in incidence. Aspiration is implemented on the hub wall via a slot in the comer between the hub wall and the suction surface. The CFD studies show aspiration to be sensitive to the suction flow rate; lower rate leads to very complex flow struc- tures and increased level of losses whereas higher rate renders aspiration effective for control of hub comer separation. The flow topologies are studied by trace of skin friction lines on the walls. The nature of flow can be explained by the topological rules of closed separation. Furthermore, a deeper analysis is done for a particular case with advanced criterion to test the non-degeneracy of critical points in the flow field.展开更多
Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma ...Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma pathobiology.Conventional cell culture-based research(2D cell culture)is still playing a pivotal role,while several shortcomings have been recently under discussion.In vivo,mouse models are usually adopted for pre-clinical analyses with expectations to overcome the issues of 2D cell culture.However,they do not fully recapitulate human dedifferentiated liposarcoma(DDLPS)characteristics.Therefore,three-dimensional(3D)culture systems have been the recent research focus in the cell biology field with the expectation to overcome at the same time the disadvantages of 2D cell culture and in vivo animal models and fill in the gap between them.Given the liposarcoma rarity,we believe that 3D cell culture techniques,including 3D cell cultures/co-cultures,and Patient-Derived tumor Organoids(PDOs),represent a promising approach to facilitate liposarcoma investigation and elucidate its molecular mechanisms and effective therapy development.In this review,we first provide a general overview of 3D cell cultures compared to 2D cell cultures.We then focus on one of the recent 3D cell culture applications,Patient-Derived Organoids(PDOs),summarizing and discussing several PDO methodologies.Finally,we discuss the current and future applications of PDOs to sarcoma,particularly in the field of liposarcoma.展开更多
Bone repair remains an important target in tissue engineering,making the development of bioactive scaffolds for effective bone defect repair a critical objective.In this study,β-tricalcium phosphate(β-TCP)scaffolds ...Bone repair remains an important target in tissue engineering,making the development of bioactive scaffolds for effective bone defect repair a critical objective.In this study,β-tricalcium phosphate(β-TCP)scaffolds incorporated with processed pyritum decoction(PPD)were fabricated using three-dimensional(3D)printing-assisted freeze-casting.The produced composite scaffolds were evaluated for their mechanical strength,physicochemical properties,biocompatibility,in vitro proangiogenic activity,and in vivo efficacy in repairing rabbit femoral defects.They not only demonstrated excellent physicochemical properties,enhanced mechanical strength,and good biosafety but also significantly promoted the proliferation,migration,and aggregation of pro-angiogenic human umbilical vein endothelial cells(HUVECs).In vivo studies revealed that all scaffold groups facilitated osteogenesis at the bone defect site,with theβ-TCP scaffolds loaded with PPD markedly enhancing the expression of neurogenic locus Notch homolog protein 1(Notch1),vascular endothelial growth factor(VEGF),bone morphogenetic protein-2(BMP-2),and osteopontin(OPN).Overall,the scaffolds developed in this study exhibited strong angiogenic and osteogenic capabilities both in vitro and in vivo.The incorporation of PPD notably promoted the angiogenic-osteogenic coupling,thereby accelerating bone repair,which suggests that PPD is a promising material for bone repair and that the PPD/β-TCP scaffolds hold great potential as a bone graft alternative.展开更多
To facilitate the low-noise design of tandem lift bodies as applied in aeroengines and aircraft,the acoustic features of tandem blades are investigated by wind-tunnel experiments.This is further specialized for the ro...To facilitate the low-noise design of tandem lift bodies as applied in aeroengines and aircraft,the acoustic features of tandem blades are investigated by wind-tunnel experiments.This is further specialized for the rotating blades applied in contra-rotating open rotors under the concept of frozen-rotor.A 70-channel phased microphone array and nine high-precision free-field microphones are employed.The beamforming method,enhanced by a source filtering technique,is employed to locate noise sources,providing insights into the source patterns of blade-blade interaction noise concerning flow speed,blade spacing,and aft blade clipping.The results show the following:(A)Sources of tandem-blade noise exist in the form of concentrated source clusters,resulting in two major clusters:the mid-span interaction noise and the tip-induced noise.(B)These source clusters tend to separate as flow speed or blade spacing increases.(C)By increasing blade spacing,the band-pass filtered overall sound pressure level is reduced by 2.9 dB.(D)A two-phase noise suppression pattern is observed with blade clipping,resulting in a total reduction of 3.0 dB for the interaction noise through the removal of tip-induced noise sources and the replacement of mid-span noise sources.Based on these findings,suggestions concerning blade spacing and clipping are discussed.展开更多
An optimized device structure for reducing the RESET current of phase-change random access memory （PCRAM） with blade-type like （BTL） phase change layer is proposed. The electrical thermal analysis of the BTL cell ...An optimized device structure for reducing the RESET current of phase-change random access memory （PCRAM） with blade-type like （BTL） phase change layer is proposed. The electrical thermal analysis of the BTL cell and the blade heater contactor structure by three-dimensional finite element modeling are compared with each other during RESET operation. The simulation results show that the programming region of the phase change layer in the BTL cell is much smaller, and thermal electrical distributions of the BTL cell are more concentrated on the TiN/GST interface. The results indicate that the BTL cell has the superiorities of increasing the heating efficiency, decreasing the power consumption and reducing the RESET current from 0.67mA to 0.32mA. Therefore, the BTL cell will be appropriate for high performance PCRAM device with lower power consumption and lower RESET current.展开更多
The development of minimally invasive surgery has transformed the management of gastrointestinal cancer.Notably,three-dimensional visualization systems have increased surgical precision.This editorial discusses a rece...The development of minimally invasive surgery has transformed the management of gastrointestinal cancer.Notably,three-dimensional visualization systems have increased surgical precision.This editorial discusses a recent study by Shen and Zhang,which compared the clinical applications of naked-eye threedimensional laparoscopic systems vs traditional optical systems in radical surgery for gastric and colorectal cancer.Both systems appeared to yield comparable surgical and oncological outcomes in terms of safety parameters,operating times,and quality of lymph node dissection.However,the spectacle-free system’s technical and logistical limitations hindered its effects on the surgical team’s overall competency.This editorial examines the authors’findings within the broader context of the evolution of oncologic laparoscopy,discusses the relevance of the results in light of the current literature,and proposes future research directions focused on multicenter validation,comprehensive ergonomic analysis,and technological advancements aimed at enhancing intraoperative collaboration.As technology continues to evolve,clinical implementation of new methods must be supported by robust scientific evidence and standardized criteria,to ensure tangible improvements in efficiency,safety,and oncologic outcomes.展开更多
The three-dimensional particle electrode system exhibits significant potential for application in the treatment of wastewater.Nonetheless,the advancement of effective granular electrodes characterized by elevated cata...The three-dimensional particle electrode system exhibits significant potential for application in the treatment of wastewater.Nonetheless,the advancement of effective granular electrodes characterized by elevated catalytic activity and minimal energy consumption continues to pose a significant challenge.In this research,Fluorine-doped copper-carbon(F/Cu-GAC)particle electrodes were effectively synthesized through an impregnationcalcination technique,utilizing granular activated carbon as the carrier and fluorinedoped modified copper oxides as the catalytic agents.The particle electrodes were subsequently utilized to promote the degradation of 2,4,6-trichlorophenol(2,4,6-TCP)in a threedimensional electrocatalytic reactor(3DER).The F/Cu-GAC particle electrodes were polarized under the action of electric field,which promoted the heterogeneous Fenton-like reaction in which H2O2 generated by two-electron oxygen reduction reaction(2e-ORR)of O_(2) was catalytically decomposed to·OH.The 3DER equipped with F/Cu-GAC particle electrodes showed 100%removal of 2,4,6-TCP and 79.24%removal of TOC with a specific energy consumption(EC)of approximately 0.019 kWh/g·COD after 2 h of operation.The F/Cu-GAC particle electrodes exhibited an overpotential of 0.38 V and an electrochemically active surface area(ECSA)of 715 cm^(2),as determined through linear sweep voltammetry(LSV)and cyclic voltammetry(CV)assessments.These findings suggest a high level of electrocatalytic performance.Furthermore,the catalytic mechanism of the 3DER equipped with F/Cu-GAC particle electrodes was elucidated through the application of X-ray photoelectron spectroscopy(XPS),electron spin resonance(ESR),and active species capture experiments.This investigation offers a novel approach for the effective degradation of 2,4,6-TCP.展开更多
This study investigates the forced vibration response of a two-row model of an Inlet Guide Vane(IGV)and rotor at resonance speed through numerical simulations.A resonant response prediction method based on equivalent ...This study investigates the forced vibration response of a two-row model of an Inlet Guide Vane(IGV)and rotor at resonance speed through numerical simulations.A resonant response prediction method based on equivalent damping balance has been validated,which ensures computational accuracy while reducing response calculation time to only 1%of the traditional transient response method.At resonance speed,unsteady pressure disturbances on the rotor blade surface mainly arise from two sources:IGV wakes and blade vibrations.The unsteady pressure caused by the IGV wakes provides excitation for the system,while the unsteady pressure caused by rotor blade vibrations provides damping.By studying the characteristics of unsteady pressure caused by IGV wakes and vibrations at resonance speed,a method for separating unsteady pressure caused by stator wakes and vibrations has been presented,accurately obtaining aerodynamic damping under multi-row resonance conditions.Compared to the aerodynamic damping obtained from multi-row scenarios without separating unsteady pressures caused by stator wakes and vibrations,and the traditional isolated blade row scheme,the aerodynamic damping considering the effects of multi-row and IGV wakes at resonance speed is smaller.Based on the separated unsteady pressures caused by IGV wakes and vibrations,and combined with the equivalent damping balance method for predicting forced response,a forced response analysis method considering both flow field disturbance excitation and damping effects has been established.展开更多
The turbine blades operate under high temperature and high pressure conditions,and when using radiation thermometry,the influence of radiation from surrounding blades leads to measurement errors.To address this issue,...The turbine blades operate under high temperature and high pressure conditions,and when using radiation thermometry,the influence of radiation from surrounding blades leads to measurement errors.To address this issue,this paper develops a three-dimensional discretized dynamic radiation transfer model based on the blade shape of the turbine.The relationship between the radiation angle coefficient of the surrounding blades and the rotation angle of the blade under test is analyzed.The radiation angle coefficient is calculated using the triangular element method,and temperature inversion is performed based on the effective emissivity to compute the measurement error.The results show that under dynamic high temperature conditions,the temperature measurement error caused by reflection at the selected 60%leaf height point varies with the rotation angle,and the maximum reaches 25.58K.The angular coefficient exhibits periodic fluctuations with changes in rotation angle,and the maximum effective emissivity increases as the rotation angle increases.As the blade height increases,the impact of reflected radiation on radiometric temperature measurement errors shows a decreasing trend.This study provides a reference for radiation thermometry in dynamic high-temperature environments.展开更多
In this study,CiteSpace software is used to carry out visual analysis on the three-dimensional research literature on urban recreation space from the perspective of compact city theory in the past 20 years,exploring t...In this study,CiteSpace software is used to carry out visual analysis on the three-dimensional research literature on urban recreation space from the perspective of compact city theory in the past 20 years,exploring the scientific development trend and research hotspots in this field.The results show that the number of published documents shows a fluctuating upward trend,and the significant growth rate reflects the role of policy orientation in promoting the concept of compact city.The co-occurrence analysis of keywords reveals the research hotspots of“compact city”,“recreation space”and“urban park”,while the emergence of new keywords such as“vertical city”and“spatial justice”indicates the new trend of recent research.The cluster analysis and timeline map further show the evolution of research themes,with“compact city”being the largest cluster and having rich connections with other themes such as“urban design”and“urban park”.展开更多
Blades are important parts of rotating machinery such as marine gas turbines and wind turbines,which are exposed to harsh environments during mechanical operations,including centrifugal loads,aerodynamic forces,or hig...Blades are important parts of rotating machinery such as marine gas turbines and wind turbines,which are exposed to harsh environments during mechanical operations,including centrifugal loads,aerodynamic forces,or high temperatures.These demanding working conditions considerably influence the dynamic performance of blades.Therefore,because of the challenges posed by blades in complex working environments,in-depth research and optimization are necessary to ensure that blades can operate safely and efficiently,thus guaranteeing the reliability and performance of mechanical systems.Focusing on the vibration analysis of blades in rotating machinery,this paper conducts a comprehensive literature review on the research advancements in vibration modeling and structural optimization of blades under complex operational conditions.First,the paper outlines the development of several modeling theories for rotating blades,including one-dimensional beam theory,two-dimensional plate-shell theory,and three-dimensional solid theory.Second,the research progress in the vibrational analysis of blades under aerodynamic loads,thermal environments,and crack factors is separately discussed.Finally,the developments in rotating blade structural optimization are presented from material optimization and shape optimization perspectives.The methodology and theory of analyzing and optimizing blade vibration characteristics under multifactorial operating conditions are comprehensively outlined,aiming to assist future researchers in proposing more effective and practical approaches for the vibration analysis and optimization of blades.展开更多
BACKGROUND Ganglioneuroma is a rare,well-differentiated,slow-growing benign tumor of the peripheral nerves,with surgical resection being the only curative treatment.Surgical resection of ganglioneuromas encasing major...BACKGROUND Ganglioneuroma is a rare,well-differentiated,slow-growing benign tumor of the peripheral nerves,with surgical resection being the only curative treatment.Surgical resection of ganglioneuromas encasing major blood vessels remains a substantial clinical challenge.Traditionally,these cases often require open abdominal surgery or combined organ resections,and in some instances,the tumors are considered unresectable.Currently,no reports have described the resection of such tumors via laparoscopy.CASE SUMMARY A 35-year-old woman was admitted to our hospital after the incidental discovery of a retroperitoneal space-occupying lesion.Imaging revealed a mass with the celiac axis and superior mesenteric artery passing through it.A neurogenic tumor was suspected,with ganglioneuroma being the most likely diagnosis.Following comprehensive preoperative preparation,the retroperitoneal tumor was resected using a three-dimensional laparoscopy combined with an organ suspension technique.The surgical approach involved incising the tumor along the vascular axis and conducting meticulous,vascular-preserving tumor excision.The operation lasted approximately 458 minutes,with an estimated blood loss of 50 mL.The patient was discharged on the 8th postoperative day.A transient liver injury occurred after surgery but improved rapidly.After 11 months of postoperative follow-up,no complications or tumor recurrence were observed.CONCLUSION This case illustrates the feasibility of minimally invasive laparoscopic resection for retroperitoneal ganglioneuromas encasing major blood vessels.展开更多
Thermal metamaterial represents a groundbreaking approach to control heat conduction,and,as a crucial component,thermal invisibility is of utmost importance for heat management.Despite the flourishing development of t...Thermal metamaterial represents a groundbreaking approach to control heat conduction,and,as a crucial component,thermal invisibility is of utmost importance for heat management.Despite the flourishing development of thermal invisibility schemes,they still face two limitations in practical applications.First,objects are typically completely enclosed in traditional cloaks,making them difficult to use and unsuitable for objects with heat sources.Second,although some theoretical proposals have been put forth to change the thermal conductivity of materials to achieve dynamic invisibility,their designs are complex and rigid,making them unsuitable for large-scale use in real threedimensional(3D)spaces.Here,we propose a concept of a thermal dome to achieve 3D invisibility.Our scheme includes an open functional area,greatly enhancing its usability and applicability.It features a reconfigurable structure,constructed with simple isotropic natural materials,making it suitable for dynamic requirements.The performance of our reconfigurable thermal dome has been confirmed through simulations and experiments,consistent with the theory.The introduction of this concept can greatly advance the development of thermal invisibility technology from theory to engineering and provide inspiration for other physical domains,such as direct current electric fields and magnetic fields.展开更多
The dispersibility of active components in hydrodesulfurization(HDS)catalysts significantly influences the corresponding catalytic performance.In this study,sugar-based materials(glucose,chitosan,soluble starch,and co...The dispersibility of active components in hydrodesulfurization(HDS)catalysts significantly influences the corresponding catalytic performance.In this study,sugar-based materials(glucose,chitosan,soluble starch,and corn starch)were utilized to prepare CoMo bulk HDS catalysts through a sugar foaming process.The foaming intermediates were analyzed using TG,FTIR,and Raman techniques to investigate the pyrolysis and carbonization process,revealing the presence of graphitic carbon in the 3 DPG,3 DPSS,and 3 DPCS catalysts even after calcination in an air atmosphere.The catalysts were further characterized using SEM,XRD,TEM,low-temperature N_(2) physical adsorption,and XPS.The 3 DPSS catalyst exhibited a thiophene conversion of 94.8%at 360℃ and 1 MPa,which could be ascribed to its unique three-dimensional pore structure,high dispersion of MoS_(2)(0.21),and high fraction of Mo^(4+)(83.14%).This study demonstrates the potential of using the sugar foaming technique to develop highly efficient HDS catalysts and provides new insights into the relationship between the physicochemical properties of the obtained catalysts and their catalytic performance.展开更多
To address the recycling challenges posed by the global peak of wind turbine blade retirement,this study aims to establish a decision-making model for reverse logistics modes of decommissioned blades,resolving the mul...To address the recycling challenges posed by the global peak of wind turbine blade retirement,this study aims to establish a decision-making model for reverse logistics modes of decommissioned blades,resolving the multi-agent collaborative optimization problem under ultra-high logistics cost constraints.Based on the characteristics of centralized sourcing and determinable elements in blade reverse logistics,we developed three models dominated by wind power equipment manufacturers,operators,and third-party enterprises,respectively.The research analyzes influencing factors on reverse logistics mode selection and proposes a threshold decision mechanism for mode selection.Key findings reveal:technological strength serves as the core driver for manufacturer-dominated models;channel efficiency determines the applicability of operator-led models;insufficient economies of scale may hinder third-party model development.This study provides decision-making foundations for the resource utilization of decommissioned blades.展开更多
基金The National Natural Science Foundation of China(No.52171274).
文摘Spiral pile foundations,as a promising type of foundation,are of significant importance for the development of offshore wind energy,particularly as it moves toward deeper waters.This study conducted a physical experiment on a three-spiral-pile jacket foundation under deep-buried sandy soil conditions.During the experiment,horizontal displacement was applied to the structure to thoroughly investigate the bearing characteristics of the three-spiral-pile jacket foundation.This study also focused on analyzing the bearing mechanisms of conventional piles compared with spiral piles with different numbers of blades.Three different working conditions were set up and compared,and key data,such as the horizontal bearing capacity,pile shaft axial force,and spiral blade soil pressure,were measured and analyzed.The results show the distinct impacts of the spiral blades on the compressed and tensioned sides of the foundation.Specifically,on the compressed side,the spiral blades effectively enhance the restraint of the soil on the pile foundation,whereas on the tensioned side,an excessive number of spiral blades can negatively affect the structural tensile performance to some extent.This study also emphasizes that the addition of blades to the side of a single pile is the most effective method for increasing the bearing capacity of the foundation.This research aims to provide design insights into improving the bearing capacity of the foundation.
基金supported by the National Science Fund for Distinguished Young Scholars(42225107)the National Natural Science Foundation of China(42001326,42371414,42171409,and 42271419)+1 种基金the Natural Science Foundation of Guangdong Province of China(2022A1515012207)the Basic and Applied Basic Research Project of Guangzhou Science and Technology Planning(202201011539)。
文摘Three-dimensional(3D)urban structures play a critical role in informing climate mitigation strategies aimed at the built environment and facilitating sustainable urban development.Regrettably,there exists a significant gap in detailed and consistent data on 3D building space structures with global coverage due to the challenges inherent in the data collection and model calibration processes.In this study,we constructed a global urban structure(GUS-3D)dataset,including building volume,height,and footprint information,at a 500 m spatial resolution using extensive satellite observation products and numerous reference building samples.Our analysis indicated that the total volume of buildings worldwide in2015 exceeded 1×10^(12)m^(3).Over the 1985 to 2015 period,we observed a slight increase in the magnitude of 3D building volume growth(i.e.,it increased from 166.02 km3 during the 1985–2000 period to 175.08km3 during the 2000–2015 period),while the expansion magnitudes of the two-dimensional(2D)building footprint(22.51×10^(3) vs 13.29×10^(3)km^(2))and urban extent(157×10^(3) vs 133.8×10^(3)km^(2))notably decreased.This trend highlights the significant increase in intensive vertical utilization of urban land.Furthermore,we identified significant heterogeneity in building space provision and inequality across cities worldwide.This inequality is particularly pronounced in many populous Asian cities,which has been overlooked in previous studies on economic inequality.The GUS-3D dataset shows great potential to deepen our understanding of the urban environment and creates new horizons for numerous 3D urban studies.
基金supported by the National Natural Science Foundation of China(Grant No.52271087).
文摘Thermal barrier coatings(TBCs)are extensively utilized in aero-engines and heavy-duty gas turbines due to their outstanding properties,including low thermal conductivity,corrosion,high-temperature oxidation,and wear resistance.The rising thrust-to-weight ratio and service temperature in engine hot sections have presented a significant challenge in TBC's materials,structure,and preparation process;it is one of the current research hotspots in the aviation field.This paper reviews the recent advancement in turbine blade TBCs.It focuses on the TBC's structure,deposition mechanism and the key performance evaluation indexes for TBCs applied to turbine blades.Finally,the future research field of TBCs for turbine blades is also be prospected.
文摘To address the problem of multi-missile cooperative interception against maneuvering targets at a prespecified impact time and desired Line-of-Sight(LOS)angles in ThreeDimensional(3D)space,this paper proposes a 3D leader-following cooperative interception guidance law.First,in the LOS direction of the leader,an impact time-controlled guidance law is derived based on the fixed-time stability theory,which enables the leader to complete the interception task at a prespecified impact time.Next,in the LOS direction of the followers,by introducing a time consensus tracking error function,a fixed-time consensus tracking guidance law is investigated to guarantee the consensus tracking convergence of the time-to-go.Then,in the direction normal to the LOS,by combining the designed global integral sliding mode surface and the second-order Sliding Mode Control(SMC)theory,an innovative 3D LOS-angle-constrained interception guidance law is developed,which eliminates the reaching phase in the traditional sliding mode guidance laws and effectively saves energy consumption.Moreover,it effectively suppresses the chattering phenomenon while avoiding the singularity issue,and compensates for unknown interference caused by target maneuvering online,making it convenient for practical engineering applications.Finally,theoretical proof analysis and multiple sets of numerical simulation results verify the effectiveness,superiority,and robustness of the investigated guidance law.
文摘This paper presents a numerical study of the flow topologies of three-dimensional （3D） flows in a high pressure compressor stator blade row without and with boundary layer aspiration on the hub wall. The stator blade is representative of the first stage operating under transonic inlet conditions and the blade design encourages development of highly complex 3D flows. The blade has a small tip clearance. The computational fluid dynamics （CFD） studies show progressive increase of hub corner stall with the increase in incidence. Aspiration is implemented on the hub wall via a slot in the comer between the hub wall and the suction surface. The CFD studies show aspiration to be sensitive to the suction flow rate; lower rate leads to very complex flow struc- tures and increased level of losses whereas higher rate renders aspiration effective for control of hub comer separation. The flow topologies are studied by trace of skin friction lines on the walls. The nature of flow can be explained by the topological rules of closed separation. Furthermore, a deeper analysis is done for a particular case with advanced criterion to test the non-degeneracy of critical points in the flow field.
文摘Liposarcoma is one of the most common soft tissue sarcomas,however,its occurrence rate is still rare compared to other cancers.Due to its rarity,in vitro experiments are an essential approach to elucidate liposarcoma pathobiology.Conventional cell culture-based research(2D cell culture)is still playing a pivotal role,while several shortcomings have been recently under discussion.In vivo,mouse models are usually adopted for pre-clinical analyses with expectations to overcome the issues of 2D cell culture.However,they do not fully recapitulate human dedifferentiated liposarcoma(DDLPS)characteristics.Therefore,three-dimensional(3D)culture systems have been the recent research focus in the cell biology field with the expectation to overcome at the same time the disadvantages of 2D cell culture and in vivo animal models and fill in the gap between them.Given the liposarcoma rarity,we believe that 3D cell culture techniques,including 3D cell cultures/co-cultures,and Patient-Derived tumor Organoids(PDOs),represent a promising approach to facilitate liposarcoma investigation and elucidate its molecular mechanisms and effective therapy development.In this review,we first provide a general overview of 3D cell cultures compared to 2D cell cultures.We then focus on one of the recent 3D cell culture applications,Patient-Derived Organoids(PDOs),summarizing and discussing several PDO methodologies.Finally,we discuss the current and future applications of PDOs to sarcoma,particularly in the field of liposarcoma.
基金supported by the National Science Foundation of China(Nos.81373970,81773902,81973484,and 32171402)the National College Students Innovation and Entrepreneurship Training Program(No.201810315019)+4 种基金the Postgraduate Research and Practice Innovation Program of Jiangsu Province(Nos.SJCX21_0712 and KYCX23_2052)the Scientific Research Project of Jiangsu Provincial Association of Traditional Chinese Medicine(No.XYLD2024013)the Youth Scientific Research Project of Jiangyin Municipal Health Commission(No.Q202402)the Natural Science Foundation Project of Nanjing University of Chinese Medicine(No.XZR2024173)the Jiangyin Science and Technology Innovation Special Fund Project(No.JY0603A011014230032PB),China.
文摘Bone repair remains an important target in tissue engineering,making the development of bioactive scaffolds for effective bone defect repair a critical objective.In this study,β-tricalcium phosphate(β-TCP)scaffolds incorporated with processed pyritum decoction(PPD)were fabricated using three-dimensional(3D)printing-assisted freeze-casting.The produced composite scaffolds were evaluated for their mechanical strength,physicochemical properties,biocompatibility,in vitro proangiogenic activity,and in vivo efficacy in repairing rabbit femoral defects.They not only demonstrated excellent physicochemical properties,enhanced mechanical strength,and good biosafety but also significantly promoted the proliferation,migration,and aggregation of pro-angiogenic human umbilical vein endothelial cells(HUVECs).In vivo studies revealed that all scaffold groups facilitated osteogenesis at the bone defect site,with theβ-TCP scaffolds loaded with PPD markedly enhancing the expression of neurogenic locus Notch homolog protein 1(Notch1),vascular endothelial growth factor(VEGF),bone morphogenetic protein-2(BMP-2),and osteopontin(OPN).Overall,the scaffolds developed in this study exhibited strong angiogenic and osteogenic capabilities both in vitro and in vivo.The incorporation of PPD notably promoted the angiogenic-osteogenic coupling,thereby accelerating bone repair,which suggests that PPD is a promising material for bone repair and that the PPD/β-TCP scaffolds hold great potential as a bone graft alternative.
基金supported by grants from the National Natural Science Foundation of China(Nos.12102451,12072186)the National Science and Technology Major Project,China(No.J2019-II-0006-0026)AVIC Aerodynamics Research Institute,China(No.XFX20220201).
文摘To facilitate the low-noise design of tandem lift bodies as applied in aeroengines and aircraft,the acoustic features of tandem blades are investigated by wind-tunnel experiments.This is further specialized for the rotating blades applied in contra-rotating open rotors under the concept of frozen-rotor.A 70-channel phased microphone array and nine high-precision free-field microphones are employed.The beamforming method,enhanced by a source filtering technique,is employed to locate noise sources,providing insights into the source patterns of blade-blade interaction noise concerning flow speed,blade spacing,and aft blade clipping.The results show the following:(A)Sources of tandem-blade noise exist in the form of concentrated source clusters,resulting in two major clusters:the mid-span interaction noise and the tip-induced noise.(B)These source clusters tend to separate as flow speed or blade spacing increases.(C)By increasing blade spacing,the band-pass filtered overall sound pressure level is reduced by 2.9 dB.(D)A two-phase noise suppression pattern is observed with blade clipping,resulting in a total reduction of 3.0 dB for the interaction noise through the removal of tip-induced noise sources and the replacement of mid-span noise sources.Based on these findings,suggestions concerning blade spacing and clipping are discussed.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No XDA09020402the National Integrate Circuit Research Program of China under Grant No 2009ZX02023-003+1 种基金the National Natural Science Foundation of China under Grant Nos 61261160500,61376006,61401444 and 61504157the Science and Technology Council of Shanghai under Grant Nos 14DZ2294900,15DZ2270900 and 14ZR1447500
文摘An optimized device structure for reducing the RESET current of phase-change random access memory （PCRAM） with blade-type like （BTL） phase change layer is proposed. The electrical thermal analysis of the BTL cell and the blade heater contactor structure by three-dimensional finite element modeling are compared with each other during RESET operation. The simulation results show that the programming region of the phase change layer in the BTL cell is much smaller, and thermal electrical distributions of the BTL cell are more concentrated on the TiN/GST interface. The results indicate that the BTL cell has the superiorities of increasing the heating efficiency, decreasing the power consumption and reducing the RESET current from 0.67mA to 0.32mA. Therefore, the BTL cell will be appropriate for high performance PCRAM device with lower power consumption and lower RESET current.
文摘The development of minimally invasive surgery has transformed the management of gastrointestinal cancer.Notably,three-dimensional visualization systems have increased surgical precision.This editorial discusses a recent study by Shen and Zhang,which compared the clinical applications of naked-eye threedimensional laparoscopic systems vs traditional optical systems in radical surgery for gastric and colorectal cancer.Both systems appeared to yield comparable surgical and oncological outcomes in terms of safety parameters,operating times,and quality of lymph node dissection.However,the spectacle-free system’s technical and logistical limitations hindered its effects on the surgical team’s overall competency.This editorial examines the authors’findings within the broader context of the evolution of oncologic laparoscopy,discusses the relevance of the results in light of the current literature,and proposes future research directions focused on multicenter validation,comprehensive ergonomic analysis,and technological advancements aimed at enhancing intraoperative collaboration.As technology continues to evolve,clinical implementation of new methods must be supported by robust scientific evidence and standardized criteria,to ensure tangible improvements in efficiency,safety,and oncologic outcomes.
基金supported by Guangxi Science and Technology Major Program(No.AA23073008)Hubei Key Laboratory of Water System Science for Sponge City Construction(Wuhan University)(No.2023–05)Nanning Innovation and Entrepreneur Leading Talent Project(No.2021001).
文摘The three-dimensional particle electrode system exhibits significant potential for application in the treatment of wastewater.Nonetheless,the advancement of effective granular electrodes characterized by elevated catalytic activity and minimal energy consumption continues to pose a significant challenge.In this research,Fluorine-doped copper-carbon(F/Cu-GAC)particle electrodes were effectively synthesized through an impregnationcalcination technique,utilizing granular activated carbon as the carrier and fluorinedoped modified copper oxides as the catalytic agents.The particle electrodes were subsequently utilized to promote the degradation of 2,4,6-trichlorophenol(2,4,6-TCP)in a threedimensional electrocatalytic reactor(3DER).The F/Cu-GAC particle electrodes were polarized under the action of electric field,which promoted the heterogeneous Fenton-like reaction in which H2O2 generated by two-electron oxygen reduction reaction(2e-ORR)of O_(2) was catalytically decomposed to·OH.The 3DER equipped with F/Cu-GAC particle electrodes showed 100%removal of 2,4,6-TCP and 79.24%removal of TOC with a specific energy consumption(EC)of approximately 0.019 kWh/g·COD after 2 h of operation.The F/Cu-GAC particle electrodes exhibited an overpotential of 0.38 V and an electrochemically active surface area(ECSA)of 715 cm^(2),as determined through linear sweep voltammetry(LSV)and cyclic voltammetry(CV)assessments.These findings suggest a high level of electrocatalytic performance.Furthermore,the catalytic mechanism of the 3DER equipped with F/Cu-GAC particle electrodes was elucidated through the application of X-ray photoelectron spectroscopy(XPS),electron spin resonance(ESR),and active species capture experiments.This investigation offers a novel approach for the effective degradation of 2,4,6-TCP.
基金co-supported by the National Natural Science Foundation of China(No.52306034)the National Science and Technology Major Project,China(No.J2022-IV-00100024)+1 种基金the Fundamental Research Funds for the Central Universities,Chinathe National Science and Technology Major Project,China(No.J2017-IV-0002-0039)。
文摘This study investigates the forced vibration response of a two-row model of an Inlet Guide Vane(IGV)and rotor at resonance speed through numerical simulations.A resonant response prediction method based on equivalent damping balance has been validated,which ensures computational accuracy while reducing response calculation time to only 1%of the traditional transient response method.At resonance speed,unsteady pressure disturbances on the rotor blade surface mainly arise from two sources:IGV wakes and blade vibrations.The unsteady pressure caused by the IGV wakes provides excitation for the system,while the unsteady pressure caused by rotor blade vibrations provides damping.By studying the characteristics of unsteady pressure caused by IGV wakes and vibrations at resonance speed,a method for separating unsteady pressure caused by stator wakes and vibrations has been presented,accurately obtaining aerodynamic damping under multi-row resonance conditions.Compared to the aerodynamic damping obtained from multi-row scenarios without separating unsteady pressures caused by stator wakes and vibrations,and the traditional isolated blade row scheme,the aerodynamic damping considering the effects of multi-row and IGV wakes at resonance speed is smaller.Based on the separated unsteady pressures caused by IGV wakes and vibrations,and combined with the equivalent damping balance method for predicting forced response,a forced response analysis method considering both flow field disturbance excitation and damping effects has been established.
文摘The turbine blades operate under high temperature and high pressure conditions,and when using radiation thermometry,the influence of radiation from surrounding blades leads to measurement errors.To address this issue,this paper develops a three-dimensional discretized dynamic radiation transfer model based on the blade shape of the turbine.The relationship between the radiation angle coefficient of the surrounding blades and the rotation angle of the blade under test is analyzed.The radiation angle coefficient is calculated using the triangular element method,and temperature inversion is performed based on the effective emissivity to compute the measurement error.The results show that under dynamic high temperature conditions,the temperature measurement error caused by reflection at the selected 60%leaf height point varies with the rotation angle,and the maximum reaches 25.58K.The angular coefficient exhibits periodic fluctuations with changes in rotation angle,and the maximum effective emissivity increases as the rotation angle increases.As the blade height increases,the impact of reflected radiation on radiometric temperature measurement errors shows a decreasing trend.This study provides a reference for radiation thermometry in dynamic high-temperature environments.
基金Sponsored by the Project of Sichuan Landscape and Recreation Research Center(JGYQ2020037).
文摘In this study,CiteSpace software is used to carry out visual analysis on the three-dimensional research literature on urban recreation space from the perspective of compact city theory in the past 20 years,exploring the scientific development trend and research hotspots in this field.The results show that the number of published documents shows a fluctuating upward trend,and the significant growth rate reflects the role of policy orientation in promoting the concept of compact city.The co-occurrence analysis of keywords reveals the research hotspots of“compact city”,“recreation space”and“urban park”,while the emergence of new keywords such as“vertical city”and“spatial justice”indicates the new trend of recent research.The cluster analysis and timeline map further show the evolution of research themes,with“compact city”being the largest cluster and having rich connections with other themes such as“urban design”and“urban park”.
基金Supported by the National Natural Science Foundation of China under Grant No.52271309Natural Science Foundation of Heilongjiang Province of China under Grant No.YQ2022E104.
文摘Blades are important parts of rotating machinery such as marine gas turbines and wind turbines,which are exposed to harsh environments during mechanical operations,including centrifugal loads,aerodynamic forces,or high temperatures.These demanding working conditions considerably influence the dynamic performance of blades.Therefore,because of the challenges posed by blades in complex working environments,in-depth research and optimization are necessary to ensure that blades can operate safely and efficiently,thus guaranteeing the reliability and performance of mechanical systems.Focusing on the vibration analysis of blades in rotating machinery,this paper conducts a comprehensive literature review on the research advancements in vibration modeling and structural optimization of blades under complex operational conditions.First,the paper outlines the development of several modeling theories for rotating blades,including one-dimensional beam theory,two-dimensional plate-shell theory,and three-dimensional solid theory.Second,the research progress in the vibrational analysis of blades under aerodynamic loads,thermal environments,and crack factors is separately discussed.Finally,the developments in rotating blade structural optimization are presented from material optimization and shape optimization perspectives.The methodology and theory of analyzing and optimizing blade vibration characteristics under multifactorial operating conditions are comprehensively outlined,aiming to assist future researchers in proposing more effective and practical approaches for the vibration analysis and optimization of blades.
基金Supported by the Zhejiang Medical Science and Technology Project,No.2022KY1325 and No.2023KY381Public Welfare Project of Jinhua Science and Technology Plan,No.2023-4-084Major Project of Jinhua Science and Technology Plan,No.2023-3-066.
文摘BACKGROUND Ganglioneuroma is a rare,well-differentiated,slow-growing benign tumor of the peripheral nerves,with surgical resection being the only curative treatment.Surgical resection of ganglioneuromas encasing major blood vessels remains a substantial clinical challenge.Traditionally,these cases often require open abdominal surgery or combined organ resections,and in some instances,the tumors are considered unresectable.Currently,no reports have described the resection of such tumors via laparoscopy.CASE SUMMARY A 35-year-old woman was admitted to our hospital after the incidental discovery of a retroperitoneal space-occupying lesion.Imaging revealed a mass with the celiac axis and superior mesenteric artery passing through it.A neurogenic tumor was suspected,with ganglioneuroma being the most likely diagnosis.Following comprehensive preoperative preparation,the retroperitoneal tumor was resected using a three-dimensional laparoscopy combined with an organ suspension technique.The surgical approach involved incising the tumor along the vascular axis and conducting meticulous,vascular-preserving tumor excision.The operation lasted approximately 458 minutes,with an estimated blood loss of 50 mL.The patient was discharged on the 8th postoperative day.A transient liver injury occurred after surgery but improved rapidly.After 11 months of postoperative follow-up,no complications or tumor recurrence were observed.CONCLUSION This case illustrates the feasibility of minimally invasive laparoscopic resection for retroperitoneal ganglioneuromas encasing major blood vessels.
基金supported by the National Natural Science Foundation of China to Jiping Huang(12035004 and 12320101004)the Innovation Program of the Shanghai Municipal Education Commission to Jiping Huang(2023ZKZD06)+2 种基金the National Natural Science Foundation of China to Ying Li(92163123 and 52250191)the Zhejiang Provincial Natural Science Foundation of China to Ying Li(LZ24A050002)the National Natural Science Foundation of China to Liujun Xu(12375040,12088101,and U2330401).
文摘Thermal metamaterial represents a groundbreaking approach to control heat conduction,and,as a crucial component,thermal invisibility is of utmost importance for heat management.Despite the flourishing development of thermal invisibility schemes,they still face two limitations in practical applications.First,objects are typically completely enclosed in traditional cloaks,making them difficult to use and unsuitable for objects with heat sources.Second,although some theoretical proposals have been put forth to change the thermal conductivity of materials to achieve dynamic invisibility,their designs are complex and rigid,making them unsuitable for large-scale use in real threedimensional(3D)spaces.Here,we propose a concept of a thermal dome to achieve 3D invisibility.Our scheme includes an open functional area,greatly enhancing its usability and applicability.It features a reconfigurable structure,constructed with simple isotropic natural materials,making it suitable for dynamic requirements.The performance of our reconfigurable thermal dome has been confirmed through simulations and experiments,consistent with the theory.The introduction of this concept can greatly advance the development of thermal invisibility technology from theory to engineering and provide inspiration for other physical domains,such as direct current electric fields and magnetic fields.
基金supported by the Natural Science Foundation of Shandong Province(ZR2022MB019,ZR2021MB134)the National Natural Science Foundation of China(22008131,51974086)。
文摘The dispersibility of active components in hydrodesulfurization(HDS)catalysts significantly influences the corresponding catalytic performance.In this study,sugar-based materials(glucose,chitosan,soluble starch,and corn starch)were utilized to prepare CoMo bulk HDS catalysts through a sugar foaming process.The foaming intermediates were analyzed using TG,FTIR,and Raman techniques to investigate the pyrolysis and carbonization process,revealing the presence of graphitic carbon in the 3 DPG,3 DPSS,and 3 DPCS catalysts even after calcination in an air atmosphere.The catalysts were further characterized using SEM,XRD,TEM,low-temperature N_(2) physical adsorption,and XPS.The 3 DPSS catalyst exhibited a thiophene conversion of 94.8%at 360℃ and 1 MPa,which could be ascribed to its unique three-dimensional pore structure,high dispersion of MoS_(2)(0.21),and high fraction of Mo^(4+)(83.14%).This study demonstrates the potential of using the sugar foaming technique to develop highly efficient HDS catalysts and provides new insights into the relationship between the physicochemical properties of the obtained catalysts and their catalytic performance.
文摘To address the recycling challenges posed by the global peak of wind turbine blade retirement,this study aims to establish a decision-making model for reverse logistics modes of decommissioned blades,resolving the multi-agent collaborative optimization problem under ultra-high logistics cost constraints.Based on the characteristics of centralized sourcing and determinable elements in blade reverse logistics,we developed three models dominated by wind power equipment manufacturers,operators,and third-party enterprises,respectively.The research analyzes influencing factors on reverse logistics mode selection and proposes a threshold decision mechanism for mode selection.Key findings reveal:technological strength serves as the core driver for manufacturer-dominated models;channel efficiency determines the applicability of operator-led models;insufficient economies of scale may hinder third-party model development.This study provides decision-making foundations for the resource utilization of decommissioned blades.
