A cold compressor blade deforms elastically under aerodynamic and centrifugal loads during operation,transforming into a hot blade configuration.Blade deformation has a significant effect on the performance of compres...A cold compressor blade deforms elastically under aerodynamic and centrifugal loads during operation,transforming into a hot blade configuration.Blade deformation has a significant effect on the performance of compressor.A nonlinear pre⁃deformation method for compressor rotor blade was developed with consideration of the nonlinear features of blade stiffness and load which varies with blade configuration.In the blade profile design phase,the method can be used to compensate the aeroelastic deformation of the blade during operation.The adverse effects of blade deflection on compressor performance and structure can be avoided by the pre⁃deformation method.Due to the fact that the nonlinear method is sensitive to initial value,a load incremental method was applied to calculate initial blade deformation to stabilize and accelerate the pre⁃deformation method.The developed method was used to predict the manufactured configuration of the Stage 37 rotor blade.The variation rules of aerodynamic and structure parameters of the pre⁃deformed blade were analyzed under off⁃design conditions.Results show that the developed method ensures that under the design condition there was a good match between the actual blade configuration during operation and the intended design blade profile.The blade untwist angle of pre⁃deformed blade could be 0°at design point.Meanwhile,the tip clearance only decreased 0.2%.When the working speed was faster than 80%design speed,the performance of the pre⁃deformed blade agreed with that of the design blade.However,the mass flow rate and the total pressure ratio of the pre⁃deformed blade were lower at low speeds.展开更多
Surface and interfacial behavior of protein molecules are crucial for the protein function involved in many biochemical processes and biomedical products such as enzyme design,bio-separation,drug design and delivery.T...Surface and interfacial behavior of protein molecules are crucial for the protein function involved in many biochemical processes and biomedical products such as enzyme design,bio-separation,drug design and delivery.This article is devoted to an overview of design and regulation of the surface and interfacial behavior of protein molecules.The improvement of enzyme surface such as the directed evolution and the rational design of enzymes is introduced at first,followed by the rational design of protein interface for the protein assembly.Thereafter,the design of micro-environment and ligands are described as two examples for the design guided by protein surface.Then the design of protein surface and interface with the help of artificial intelligence will be discussed.展开更多
Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud fede...Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud federation. Data transmissions required for inter-cloud federation in the complex inter-cloud networking system are often point-to-multi points, which calls for a more effective and efficient multicast routing algorithm in complex networking systems. In this paper, we investigate the multicast routing problem in the inter-cloud context with K constraints where K ≥ 2. Unlike most of existing algorithms that are too complex to be applied in practical scenarios, a novel and fast algorithm for establishing multicast routing tree for interclouds is proposed. The proposed algorithm leverages an entropybased process to aggregate all weights into a comprehensive metric, and then uses it to search a multicast tree(MT) on the basis of the shortest path tree(SPT). We conduct complexity analysis and extensive simulations for the proposed algorithm from the approximation perspective. Both analytical and experimental results demonstrate that the algorithm is more efficient than a representative multi-constrained multicast routing algorithm in terms of both speed and accuracy, and thus we believe that the proposed algorithm is applicable to the inter-cloud environment.展开更多
In vitro and in vivo testing can provide insight into knee joint mechanics and implant performance.However,these methods are costly and time-consuming,which always limits their widespread use during the design stage o...In vitro and in vivo testing can provide insight into knee joint mechanics and implant performance.However,these methods are costly and time-consuming,which always limits their widespread use during the design stage of the implant.This review presents a critical analysis of computational modelling(in-silicon)techniques including(i)development of a generic model of total knee replacement(TKR)and application of material properties,loading,and boundary conditions;(ii)design and execution of computational experiments;and(iii)practical applications and significant findings.The results show that the generic model and techniques provide significant insight into the general performance of TKR but have limited explicit validation.The introduction of design-of-experiments,probabilistic,and neural network methodologies in computational modelling has enabled simulation at the population level.Further advances in subjective modelling appear to be limited,mainly because of the lack of subjective materials and boundary conditions.Computational modelling will increasingly be used in the preclinical testing and design of TKR.This modelling should include subjective,multi-scale,and closely corroborated analyses to account for the variability of TKR.展开更多
In this paper,an ultrathin and ultrabroadband metamaterial absorber based on 3D water microchannels is proposed. The experimental results show an absorption rate over 90%and a relative bandwidth up to 165%in the frequ...In this paper,an ultrathin and ultrabroadband metamaterial absorber based on 3D water microchannels is proposed. The experimental results show an absorption rate over 90%and a relative bandwidth up to 165%in the frequency band between 9.6 and 98.9 GHz. This polarization-independent absorber can work at a wide angle of incidence and exhibits good thermal stability. Benefiting from ultrabroadband absorption,thin thickness,low cost,and environmentally friendly materials,the proposed metamaterial absorber can be used in the fields of electromagnetic wave stealth and electromagnetic radiation protection. Related device design and research methods can be extended to the applied research in the terahertz and optical bands.展开更多
Radiation defects-induced plastic flow localization is the origin of loss of ductility in irradiated metals.Defect-free channels(DFCs)are a typical form of strain localization that lead to crack initiation and prematu...Radiation defects-induced plastic flow localization is the origin of loss of ductility in irradiated metals.Defect-free channels(DFCs)are a typical form of strain localization that lead to crack initiation and premature failure.A comprehensive understanding of the DFC dynamics is key to managing radiation boosted property degradation.Despite great research efforts,a clear mechanism of DFC remains unknown.Here,our in-situ tests on irradiated Ni pillars provide a real-time observation of the dynamics of DFCs,including DFC initiation,extension and thickening.The merging and spreading of dislocation loops serve as an alternative mechanism of dislocation sources that emit massive dislocations and initiate nano-thick DFCs inside the grain.Nano-thick DFCs were formed through chopping up or sweeping away of loops by mobile dislocations.Annihilation of opposite loops and interactions between loops and vacancies accelerate DFC extension.Activation of multiple dislocation sources and dislocation cross-slips are the mechanisms for DFC thickening.展开更多
In this paper, we show that the coupled modified Kd V equations possess rich mathematical structures and some remarkable properties. The connections between the system and skew orthogonal polynomials,convergence accel...In this paper, we show that the coupled modified Kd V equations possess rich mathematical structures and some remarkable properties. The connections between the system and skew orthogonal polynomials,convergence acceleration algorithms and Laurent property are discussed in detail.展开更多
To reduce the complexity of large-scene high-resolution maps while using the dead-end information distributed in the unmanned vehicle driving environment,we propose a novel non-uniform quadtree map-building method inc...To reduce the complexity of large-scene high-resolution maps while using the dead-end information distributed in the unmanned vehicle driving environment,we propose a novel non-uniform quadtree map-building method including dead-end semantic information extraction.By utilizing quadtree data structures,submaps and a positive-order tree depth organization approach,our proposed map can adapt to the large-scale high-resolution requirement and expand more easily to larger environments.To verify the practicality of our proposed map,we have successfully implemented map matching and path planning in real environments.Additionally,we effectively extract the dead-end semantic information that widely distributes in the environment,which can help unmanned vehicles avoid collisions and improve the search efficiency of the planning procedure.We evaluate our method with KITTI datasets,CARLA Simulator,and our self-collected real-world datasets.The experimental results show that our proposed method significantly reduces the complexity of large-scale high-resolution maps,effectively extracts dead-end semantic information,and has good practicality in real environments.The implementation of our method is released here:https://github.com/biter0088/Non-uniform-quadtree-map.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51606023)the Fundamental Research Funds for the Central Universities(Grant No.3132019204).
文摘A cold compressor blade deforms elastically under aerodynamic and centrifugal loads during operation,transforming into a hot blade configuration.Blade deformation has a significant effect on the performance of compressor.A nonlinear pre⁃deformation method for compressor rotor blade was developed with consideration of the nonlinear features of blade stiffness and load which varies with blade configuration.In the blade profile design phase,the method can be used to compensate the aeroelastic deformation of the blade during operation.The adverse effects of blade deflection on compressor performance and structure can be avoided by the pre⁃deformation method.Due to the fact that the nonlinear method is sensitive to initial value,a load incremental method was applied to calculate initial blade deformation to stabilize and accelerate the pre⁃deformation method.The developed method was used to predict the manufactured configuration of the Stage 37 rotor blade.The variation rules of aerodynamic and structure parameters of the pre⁃deformed blade were analyzed under off⁃design conditions.Results show that the developed method ensures that under the design condition there was a good match between the actual blade configuration during operation and the intended design blade profile.The blade untwist angle of pre⁃deformed blade could be 0°at design point.Meanwhile,the tip clearance only decreased 0.2%.When the working speed was faster than 80%design speed,the performance of the pre⁃deformed blade agreed with that of the design blade.However,the mass flow rate and the total pressure ratio of the pre⁃deformed blade were lower at low speeds.
基金supported by the National Natural Science Foundation of China(Nos.21978205 and 91534119)The National Key Research and Development Program of China(No.2018YFA0900700)the Innovation Foundation of Tianjin University。
文摘Surface and interfacial behavior of protein molecules are crucial for the protein function involved in many biochemical processes and biomedical products such as enzyme design,bio-separation,drug design and delivery.This article is devoted to an overview of design and regulation of the surface and interfacial behavior of protein molecules.The improvement of enzyme surface such as the directed evolution and the rational design of enzymes is introduced at first,followed by the rational design of protein interface for the protein assembly.Thereafter,the design of micro-environment and ligands are described as two examples for the design guided by protein surface.Then the design of protein surface and interface with the help of artificial intelligence will be discussed.
基金supported by the National Natural Science Foundation of China(61309031)
文摘Networking plays a crucial role in cloud computing especially in an inter-cloud environment, where data communications among data centers located at different geographical sites form the foundation of inter-cloud federation. Data transmissions required for inter-cloud federation in the complex inter-cloud networking system are often point-to-multi points, which calls for a more effective and efficient multicast routing algorithm in complex networking systems. In this paper, we investigate the multicast routing problem in the inter-cloud context with K constraints where K ≥ 2. Unlike most of existing algorithms that are too complex to be applied in practical scenarios, a novel and fast algorithm for establishing multicast routing tree for interclouds is proposed. The proposed algorithm leverages an entropybased process to aggregate all weights into a comprehensive metric, and then uses it to search a multicast tree(MT) on the basis of the shortest path tree(SPT). We conduct complexity analysis and extensive simulations for the proposed algorithm from the approximation perspective. Both analytical and experimental results demonstrate that the algorithm is more efficient than a representative multi-constrained multicast routing algorithm in terms of both speed and accuracy, and thus we believe that the proposed algorithm is applicable to the inter-cloud environment.
文摘In vitro and in vivo testing can provide insight into knee joint mechanics and implant performance.However,these methods are costly and time-consuming,which always limits their widespread use during the design stage of the implant.This review presents a critical analysis of computational modelling(in-silicon)techniques including(i)development of a generic model of total knee replacement(TKR)and application of material properties,loading,and boundary conditions;(ii)design and execution of computational experiments;and(iii)practical applications and significant findings.The results show that the generic model and techniques provide significant insight into the general performance of TKR but have limited explicit validation.The introduction of design-of-experiments,probabilistic,and neural network methodologies in computational modelling has enabled simulation at the population level.Further advances in subjective modelling appear to be limited,mainly because of the lack of subjective materials and boundary conditions.Computational modelling will increasingly be used in the preclinical testing and design of TKR.This modelling should include subjective,multi-scale,and closely corroborated analyses to account for the variability of TKR.
基金Shanghai Young College Teacher Development funding schemes (slg11006)National Natural Science Foundation of China (61205095)。
文摘In this paper,an ultrathin and ultrabroadband metamaterial absorber based on 3D water microchannels is proposed. The experimental results show an absorption rate over 90%and a relative bandwidth up to 165%in the frequency band between 9.6 and 98.9 GHz. This polarization-independent absorber can work at a wide angle of incidence and exhibits good thermal stability. Benefiting from ultrabroadband absorption,thin thickness,low cost,and environmentally friendly materials,the proposed metamaterial absorber can be used in the fields of electromagnetic wave stealth and electromagnetic radiation protection. Related device design and research methods can be extended to the applied research in the terahertz and optical bands.
基金supported by the National Natural Science Foundation of China(Grant Nos.51922082,51971170,51942104 and11675230)the National Key Research and Development Program of China(2017YFB0702301)the 111 Project of China(Grant Number BP2018008)。
文摘Radiation defects-induced plastic flow localization is the origin of loss of ductility in irradiated metals.Defect-free channels(DFCs)are a typical form of strain localization that lead to crack initiation and premature failure.A comprehensive understanding of the DFC dynamics is key to managing radiation boosted property degradation.Despite great research efforts,a clear mechanism of DFC remains unknown.Here,our in-situ tests on irradiated Ni pillars provide a real-time observation of the dynamics of DFCs,including DFC initiation,extension and thickening.The merging and spreading of dislocation loops serve as an alternative mechanism of dislocation sources that emit massive dislocations and initiate nano-thick DFCs inside the grain.Nano-thick DFCs were formed through chopping up or sweeping away of loops by mobile dislocations.Annihilation of opposite loops and interactions between loops and vacancies accelerate DFC extension.Activation of multiple dislocation sources and dislocation cross-slips are the mechanisms for DFC thickening.
基金supported by National Natural Science Foundation of China(Grant Nos.11331008,11201469,11571358 and 11601237)the China Postdoctoral Science Foundation Funded Project(Grant Nos.2012M510186 and 2013T60761)the Hong Kong Research Grant Council(Grant No.GRF HKBU202512)
文摘In this paper, we show that the coupled modified Kd V equations possess rich mathematical structures and some remarkable properties. The connections between the system and skew orthogonal polynomials,convergence acceleration algorithms and Laurent property are discussed in detail.
文摘To reduce the complexity of large-scene high-resolution maps while using the dead-end information distributed in the unmanned vehicle driving environment,we propose a novel non-uniform quadtree map-building method including dead-end semantic information extraction.By utilizing quadtree data structures,submaps and a positive-order tree depth organization approach,our proposed map can adapt to the large-scale high-resolution requirement and expand more easily to larger environments.To verify the practicality of our proposed map,we have successfully implemented map matching and path planning in real environments.Additionally,we effectively extract the dead-end semantic information that widely distributes in the environment,which can help unmanned vehicles avoid collisions and improve the search efficiency of the planning procedure.We evaluate our method with KITTI datasets,CARLA Simulator,and our self-collected real-world datasets.The experimental results show that our proposed method significantly reduces the complexity of large-scale high-resolution maps,effectively extracts dead-end semantic information,and has good practicality in real environments.The implementation of our method is released here:https://github.com/biter0088/Non-uniform-quadtree-map.
