As an advanced device for observing atmospheric winds,the spaceborne Doppler Asymmetric Spatial Heterodyne(DASH)interferometer also encounters challenges associated with phase distortion,par-ticularly in limb sounding...As an advanced device for observing atmospheric winds,the spaceborne Doppler Asymmetric Spatial Heterodyne(DASH)interferometer also encounters challenges associated with phase distortion,par-ticularly in limb sounding scenarios.This paper discusses interferogram modeling and phase distortion cor-rection techniques for spaceborne DASH interferometers.The modeling of phase distortion interferograms with and without Doppler shift for limb observation was conducted,and the effectiveness of the analytical expression was verified through numerical simulation.The simulation results indicate that errors propagate layer by layer while using the onion-peeling inversion algorithm to handle phase-distorted interferograms.In contrast,the phase distortion correction algorithm can achieve effective correction.This phase correction method can be successfully applied to correct phase distortions in the interferograms of the spaceborne DASH interferometer,providing a feasible solution to enhance its measurement accuracy.展开更多
In recent years,chiral inorganic nanomaterials have become promising candidates for applications in sensing,catalysis,biomedicine,and photonics.Plasmonic nanomaterials with an intrinsic chiral structure exhibit intrig...In recent years,chiral inorganic nanomaterials have become promising candidates for applications in sensing,catalysis,biomedicine,and photonics.Plasmonic nanomaterials with an intrinsic chiral structure exhibit intriguing geometry‑dependent optical chirality,which benefits the combination of plasmonic characteristics with chirality.Recent advances in the biomolecule‑directed geometric control of intrinsically chiral plasmonic nanomaterials have further provided great opportunities for their widespread applications in many emerging technological areas.In this review,we present the recent progress in biosensing using chiral inorganic nanomaterials,with a particular focus on electrochemical and enzyme‑mimicking catalytic approaches.This paper commences with a review of the basic tenets underlying chiral nanocatalysts,incorporating the chiral ligand‑induced mechanism and the architectures of intrinsically chiral nanostructures.Additionally,it methodically expounds upon the applications of chiral nanocatalysts in the realms of electrochemical biosensing and enzyme‑mimicking catalytic biosensing respectively.Conclusively,it proffers a prospective view of the hurdles and prospects that accompany the deployment of chiral nanoprobes for nascent biosensing applications.By rational design of the chiral nanoprobes,it is envisioned that biosensing with increasing sensitivity and resolution toward the single‑molecule level can be achieved,which will substantially promote sensing applications in many emerging interdisciplinary areas.展开更多
Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific...Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific tectonic system,the mid\|ocean ridge tectonic system and the intra\|continental tectonic system of the north hemisphere.The map shows that about 80% of the total length of the continental orogens are concentrate on the north hemisphere of the earth,of which a latitudinal mountain\|plateau chain occur within a zone between north latitude 20°and 50°.Seismic and volcanic activities demonstrate that the intracontinental tectonic system on the north hemisphere is still active.Whilst distribution of the continental deep\|focus earthquakes and almost ultra high\|pressure rock found so far over the World,that are assumed both related to recent or previous deep subduction of continent,along with this zone.The latitudinal mountain\|plateau chain is subdivided into four active tectonic region of Qinghai—Xizang(Tibet),Iranian,eastern mediterranean and North American,both characterized by an individual similar mountain\|plateau\|basin structure with major active boundaries or controlling faults (Fig.1).These active regions are all close to primary dynamic boundaries of continent\|continent collision.Solution of source mechanisms shows that regional tectonic stress field in these regions are dominated by a nearly NS or NNE—SSW direction compression corresponding to a local plate motions and a global compressive zone.Correlation between the formation of the continental latitudinal mountain\|plateau chain on north hemisphere and the oceanic plate tectonics is discussed using the information of the “Map of Magnetic Lineations of the World’s Ocean Basins (Cande et al.,1989)”and the Cenozoic and Mesozoic tectonic evolution in the continents.Total 49 accretion units formed during 6 accretion stages of the ocean spreading in three chief oceans (the Pacific,the India and the Atlantic)si nce 160Ma ago,are subdivided.The distinguished oceanic accretion tectonics in combination with the geometrical and kinematics data of adjust continental f ragments allowed outline of the development of the continental latitudinal tecto nic zone of north hemisphere.Whilst,two global asymmetrical geodynamic systems of north\|south an east\|west direction,that may be composed of meridional conve ction,latitudinal convection and inertial flow resulting from the variation of the Earth’s rotational velocity,are used to discuss on the two global geodynamic systems in which the intracontinental latitudinal tectonic zone developed.展开更多
An intuitive portrayal of the correlation between the carbon and energy markets is essential for risk control and green financial investment management.In this paper,we investigate the asymmetric spillovers between th...An intuitive portrayal of the correlation between the carbon and energy markets is essential for risk control and green financial investment management.In this paper,we investigate the asymmetric spillovers between the carbon mar-ket and energy market returns.To achieve that,we improve the Diebold-Yilmaz index model by a time-varying vector autoregressive(TVP-VAR)model.In a unified network,our daily dataset includes the closing prices of the Hubei carbon market,Shenzhen carbon market,coal futures,and energy stock index.The findings reveal that both the Hubei and Shen-zhen pilots typically generate net information spillovers on energy futures.In connection with energy stocks,the Hubei carbon market acts as a net receiver,while the Shenzhen carbon market is a net transmitter.Compared with the Hubei pi-lot,the Shenzhen pilot is more tightly connected to the energy markets.Furthermore,the spillovers of the carbon markets exhibit significant asymmetry.In most cases,they have more substantial impacts on the energy markets when the prices of emission allowances rise.The direction and magnitude of asymmetric spillovers across markets vary over time and can be influenced by certain economic or political events.展开更多
Due to the limited transmission resources for data relay in the tracking and data relay satellite system （TDRSS）, there are many job requirements in busy days which will be discarded in the conventional job scheduli...Due to the limited transmission resources for data relay in the tracking and data relay satellite system （TDRSS）, there are many job requirements in busy days which will be discarded in the conventional job scheduling model. Therefore, the improvement of scheduling efficiency in the TDRSS can not only help to increase the resource utilities, but also to reduce the scheduling failure ratio. A model of nonhomogeneous parallel machines scheduling problems with time window （NPM-TW） is firstly built up for the TDRSS, considering the distinct features of the variable preparation time and the nonhomogeneous transmission rates for different types of antennas on each tracking and data relay satellite （TDRS）. Then, an adaptive subsequence adjustment （ASA） framework with evolutionary asymmetric path-relinking （EvAPR） is proposed to solve this problem, in which an asymmetric progressive crossover operation is involved to overcome the local optima by the conventional job inserting methods. The numerical results show that, compared with the classical greedy randomized adaptive search procedure （GRASP） algorithm, the scheduling failure ratio of jobs can be reduced over 11% on average by the proposed ASA with EvAPR.展开更多
As an essential part of the industrial Internet of Things(IoT)in power systems,the development of advanced metering infrastructure(AMI)facilitates services such as energy monitoring,load forecasting,and demand respons...As an essential part of the industrial Internet of Things(IoT)in power systems,the development of advanced metering infrastructure(AMI)facilitates services such as energy monitoring,load forecasting,and demand response.However,there is a growing risk of privacy disclosure with the wide installation of smart meters,for they transmit readings and sensitive data simultaneously.To guarantee the confidentiality of the sensitive information and authenticity of smart meter readings,we proposed a privacy-preserving scheme based on digital watermarking and elliptic-curve cryptography(ECC)asymmetric encryption.The sensitive data are encrypted using the public key and are hidden in the collected readings using digital watermark.Only the authorized user can extract watermark and can decrypt the confidential data using its private key.The proposed method realizes secure end-to-end confidentiality of the sensitive information.It has faster computing speed and can verify the data source and ensure the authenticity of readings.The example results show that the proposed method has little influence on the original data and unauthorized access cannot be completed within a reasonable time.On embedded hardware,the processing speed of the proposed method is better than the existing methods.展开更多
The asymmetric semi-circular bend(ASCB)specimen has been proposed to investigate the cracking behavior in different geo and construction materials and attracted the attention of researchers due to its advantages.Howev...The asymmetric semi-circular bend(ASCB)specimen has been proposed to investigate the cracking behavior in different geo and construction materials and attracted the attention of researchers due to its advantages.However,there are few studies on the fracture toughness determination of rock materials.In this work,a series of fracture tests were performed with the ASCB specimens made of granite.The onset of fracture,crack initiation angle and crack propagating trajectory was analyzed in detail combined with several mixed mode fracture criteria.The influence of the crack length on the mode Ⅰ/Ⅱ fracture toughness was studied.A comparison between the fracture toughness ratios predicted by varying criteria and experimental results was conducted.The relationship between experimentally determined crack initiation angles and curves of the generalized maximum tangential stress(GMTS)criterion was obtained.The fracture process of the specimen was recorded with the high-speed camera.The shortcomings of the ASCB specimens for the fracture toughness determination of rock materials were discussed.The results may provide a reference for analysis of mixed mode I and II fracture behavior of brittle materials.展开更多
This paper proposes a modified centralized shifted Rayleigh filter（MCSRF） algorithm for tracking boost phase of ballistic missile（BM） trajectory with a highly nonlinear dynamical model based on bearings-only.This ...This paper proposes a modified centralized shifted Rayleigh filter（MCSRF） algorithm for tracking boost phase of ballistic missile（BM） trajectory with a highly nonlinear dynamical model based on bearings-only.This paper contributes three folds.Firstly,the mathematical model of an MCSRF for multiple passive sensors is derived.Then,minimum entropy based onedimensional optimization search to adaptively adjust the probability of the different filters for real time state estimation is deployed.Finally,the unscented transform（UT） is introduced to resolve the asymmetric state estimation problem.Simulation results show that the proposed algorithm can consecutively track the BM precisely during the boost phase.In comparison with the unscented Kalman filter（UKF） algorithm,the proposed algorithm effectively reduces the tracking position and velocity root mean square（RMS） errors,which will make more sense for early precision interception.展开更多
Effects of interrupted ageing(T6I6) and asymmetric rolling on microstructures, mechanical properties, and intergranular corrosion(IGC) behaviors of Al-Mg-Si-Zn alloy were investigated. Results showed that the T6 alloy...Effects of interrupted ageing(T6I6) and asymmetric rolling on microstructures, mechanical properties, and intergranular corrosion(IGC) behaviors of Al-Mg-Si-Zn alloy were investigated. Results showed that the T6 alloy has the lowest strength and the worst IGC resistance, while the T6I6 alloy has higher strength and better IGC resistance.What’ s more, the alloy treated by pre-rolling deformation has higher strength and better IGC resistance;and the alloy treated by the pre-asymmetry rolling achieves the highest strength, the best IGC resistance and lower elongation. The mechanical properties depend on microstructures such as the grain size, texture, dislocation density and precipitation, the grain boundary misorientation and grain boundary microstructure are responsible for the IGC resistance.展开更多
The meshing characteristic of asymmetric involute spur gear was studied, the equations of the geometric shape of the asymmetric gear for both sides were deduced, and the equations of contact ratio and the key points o...The meshing characteristic of asymmetric involute spur gear was studied, the equations of the geometric shape of the asymmetric gear for both sides were deduced, and the equations of contact ratio and the key points of contact were also obtained.Meanwhile, an involute slope modification method considering the effects of static transmission errors was proposed based on the meshing properties. The characteristic of the involute slope modification was analyzed by changing different modification parameters.The mesh stiffness and synthetic mesh stiffness of unmodified and modified asymmetric spur gears were investigated. Furthermore,the spectrums of synthetic mesh stiffness under different modification parameters were compared. Research results showed that the modification parameters influence the meshing performance of gear pairs, and the proposed modification method was feasible to improve the transmission performance of gear pairs with appropriate modification parameters.展开更多
Unequal diameter twin-roll casting(UDTRC)can improve the formability,surface conditions,and production efficiency during the fabrication of clad strips.Using Fluent software,a numerical simulation is used to study the...Unequal diameter twin-roll casting(UDTRC)can improve the formability,surface conditions,and production efficiency during the fabrication of clad strips.Using Fluent software,a numerical simulation is used to study the asymmetric heat transfer characteristics of Cu/Al clad strips fabricated by UDTRC.The effects of roller velocity ratio,Cu strip thickness,and inclination angle on the kissing point position,as well as the entire temperature distribution are obtained.The heat transfer model is established,and the mechanism is discussed.The Cu strip and rollers are found to be the main causes of asymmetric heat transfer,indicating that the roller velocity ratio changes the liquid zone proportion in the molten pool.The Cu strip thickness determines the heat absorption capacity and the variations in thermal resistance between the molten Al and the big roller.The inclination angle of the small roller changes the cooling time of big roller to molten Al.Moreover,the microstructure of Al cladding under different roller velocity ratios is examined.The results show significant grain refinement caused by the shear strain along the thickness direction of Al cladding and the intense heat transfer at the moment of contact between the metal Al cladding and Cu strip.展开更多
To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomo...To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomotive are established.The coupling vibration equations of axle hung motor and wheelset are derived.For the air braking,the influence mechanism of ABSF on the wheel-rail asymmetric motion and force characteristics are discussed.It can be found that if the ABSF is applied in the front wheelset,all the wheelsets move laterally in the same direction.Once the ABSF occurs in the middle or rear one,other wheelsets may move laterally towards the opposite direction.The motion amplitude and direction of all wheelsets strictly depend on the resultant moment of suspension yawing moment and brake shoe asymmetric moment.For the asymmetric braking,the free lateral gap of axle-box could increase the wheelset motion amplitude,but could not change the moving direction.In both the straight line and curve,the ABSF may lead to wheelset misaligning motion,intensify the wheel-rail lateral dynamic interaction and deteriorate wheel-rail contact state.Especially for the steering wheelsets,the asymmetric braking increases the wheelset attack angle significantly,which forms the worst braking condition.展开更多
The intention of this investigation is to study the effects of heat transfer and inclined magnetic field on the peristaltic flow of Williamson fluid in an asymmetric channel through porous medium. The governing two-di...The intention of this investigation is to study the effects of heat transfer and inclined magnetic field on the peristaltic flow of Williamson fluid in an asymmetric channel through porous medium. The governing two-dimensional equations are simplified under the assumption of long wavelength approximation. The simplified equations are solved for the stream function, temperature, and axial pressure gradient by using a regular perturbation method. The expression for pressure rise is computed numerically. The profiles of velocity, pressure gradient, temperature, heat transfer coefficient and stream function are sketched and interpreted for various embedded parameters and also the behavior of stream function for various wave forms is discussed through graphs. It is observed that the peristaltic velocity increases from porous medium to non-porous medium, the magnetic effects have increasing effect on the temperature, and the size of the trapped bolus decreases with the increasing of magnetic effects while the trend is reversed with the increasing of Darcy number. Moreover, limiting solutions of our problem are in close agreement with the corresponding results of the Newtonian fluid model.展开更多
A rigid-plastic finite element method(FEM) simulation model for a multi-wedge cross wedge rolling(MCWR) was developed to analyze an asymmetric stepped shaft. To evaluate the MCWR process and better understand its defo...A rigid-plastic finite element method(FEM) simulation model for a multi-wedge cross wedge rolling(MCWR) was developed to analyze an asymmetric stepped shaft. To evaluate the MCWR process and better understand its deformation characteristics, the material flowing mechanisms, temperature distributions, strain and rolling force were analyzed. The correctness of the finite element simulation is experimentally verified. Numerical simulations and experiments led to the following conclusions: when α=36° and β=7.5°, the quality of the work piece can be significantly improved. Finally, the development of the asymmetric stepped shaft is applied to industrial production.展开更多
AA1060 aluminum foil was rolled from 4 mm to 20 μm by asymmetric rolling without intermediate annealing. The microstructures and textures were investigated. The original coarse grains with an average grain size of 60...AA1060 aluminum foil was rolled from 4 mm to 20 μm by asymmetric rolling without intermediate annealing. The microstructures and textures were investigated. The original coarse grains with an average grain size of 60 μm were refined to fine equiaxed grains with an average grain size of about 500 nm with mainly large grain boundaries. During the rolling, the intensities of copper texture C-{112}<111> and brass texture B-{011}<211> gradually increased, and most crystallites aggregated along the β and τ orientation lines. The orientation intensity reached the maximum value 26 when the foil was rolled to 500 μm, but significantly decreased to 16 when the thickness became 20 μm, and the texture mainly consisted of a rotation cubic texture RC-{100}<011>. With the combined forces including drawing, compressing and shearing, severe plastic deformation was obtained during the asymmetric rolling, promoting dynamic recrystallization at room temperature. Because of a combined force in the deformation zone and shear force along the normal direction, dynamic recrystallization occurs during the asymmetric rolling; therefore, the average grain size is significantly refined. The texture intensity of ultrathin strip first increases, i.e., work hardening, and then decreases mainly because of dynamic recrystallization.展开更多
Local inhomogeneity in totally asymmetric simple exclusion processes （TASEPs） with different hopping rates was studied. Many biological and chemical phenomena can be described by these non-equilibrium processes. A s...Local inhomogeneity in totally asymmetric simple exclusion processes （TASEPs） with different hopping rates was studied. Many biological and chemical phenomena can be described by these non-equilibrium processes. A simple approximate theory and extensive Monte Carlo computer simulations were used to calculate the steady-state phase diagrams and bulk densities. It is found that the phase diagram for local inhomogeneity in TASEP with different hopping rates p is qualitatively similar to homogeneous models. Interestingly, there is a saturation point pair （a＊, fl＊） for the system, which is decided by parameters p and q. There are three stationary phases in the system, when parameter p is fixed （i.e., p=0.8）, with the increase of the parameter q, the region of LD/LD and HD/HD phase increases and the HD/LD is the only phase which the region shrinks. The analytical results are in good agreement with simulations.展开更多
文摘As an advanced device for observing atmospheric winds,the spaceborne Doppler Asymmetric Spatial Heterodyne(DASH)interferometer also encounters challenges associated with phase distortion,par-ticularly in limb sounding scenarios.This paper discusses interferogram modeling and phase distortion cor-rection techniques for spaceborne DASH interferometers.The modeling of phase distortion interferograms with and without Doppler shift for limb observation was conducted,and the effectiveness of the analytical expression was verified through numerical simulation.The simulation results indicate that errors propagate layer by layer while using the onion-peeling inversion algorithm to handle phase-distorted interferograms.In contrast,the phase distortion correction algorithm can achieve effective correction.This phase correction method can be successfully applied to correct phase distortions in the interferograms of the spaceborne DASH interferometer,providing a feasible solution to enhance its measurement accuracy.
文摘In recent years,chiral inorganic nanomaterials have become promising candidates for applications in sensing,catalysis,biomedicine,and photonics.Plasmonic nanomaterials with an intrinsic chiral structure exhibit intriguing geometry‑dependent optical chirality,which benefits the combination of plasmonic characteristics with chirality.Recent advances in the biomolecule‑directed geometric control of intrinsically chiral plasmonic nanomaterials have further provided great opportunities for their widespread applications in many emerging technological areas.In this review,we present the recent progress in biosensing using chiral inorganic nanomaterials,with a particular focus on electrochemical and enzyme‑mimicking catalytic approaches.This paper commences with a review of the basic tenets underlying chiral nanocatalysts,incorporating the chiral ligand‑induced mechanism and the architectures of intrinsically chiral nanostructures.Additionally,it methodically expounds upon the applications of chiral nanocatalysts in the realms of electrochemical biosensing and enzyme‑mimicking catalytic biosensing respectively.Conclusively,it proffers a prospective view of the hurdles and prospects that accompany the deployment of chiral nanoprobes for nascent biosensing applications.By rational design of the chiral nanoprobes,it is envisioned that biosensing with increasing sensitivity and resolution toward the single‑molecule level can be achieved,which will substantially promote sensing applications in many emerging interdisciplinary areas.
文摘Three global tectonic systems that formed since the middle Jurassic (160Ma ago)are outlined based on the global map of the Cenozoic and Mesozoic tectonics edited by Ma Zongjin et al.(1996).They are the circum\|Pacific tectonic system,the mid\|ocean ridge tectonic system and the intra\|continental tectonic system of the north hemisphere.The map shows that about 80% of the total length of the continental orogens are concentrate on the north hemisphere of the earth,of which a latitudinal mountain\|plateau chain occur within a zone between north latitude 20°and 50°.Seismic and volcanic activities demonstrate that the intracontinental tectonic system on the north hemisphere is still active.Whilst distribution of the continental deep\|focus earthquakes and almost ultra high\|pressure rock found so far over the World,that are assumed both related to recent or previous deep subduction of continent,along with this zone.The latitudinal mountain\|plateau chain is subdivided into four active tectonic region of Qinghai—Xizang(Tibet),Iranian,eastern mediterranean and North American,both characterized by an individual similar mountain\|plateau\|basin structure with major active boundaries or controlling faults (Fig.1).These active regions are all close to primary dynamic boundaries of continent\|continent collision.Solution of source mechanisms shows that regional tectonic stress field in these regions are dominated by a nearly NS or NNE—SSW direction compression corresponding to a local plate motions and a global compressive zone.Correlation between the formation of the continental latitudinal mountain\|plateau chain on north hemisphere and the oceanic plate tectonics is discussed using the information of the “Map of Magnetic Lineations of the World’s Ocean Basins (Cande et al.,1989)”and the Cenozoic and Mesozoic tectonic evolution in the continents.Total 49 accretion units formed during 6 accretion stages of the ocean spreading in three chief oceans (the Pacific,the India and the Atlantic)si nce 160Ma ago,are subdivided.The distinguished oceanic accretion tectonics in combination with the geometrical and kinematics data of adjust continental f ragments allowed outline of the development of the continental latitudinal tecto nic zone of north hemisphere.Whilst,two global asymmetrical geodynamic systems of north\|south an east\|west direction,that may be composed of meridional conve ction,latitudinal convection and inertial flow resulting from the variation of the Earth’s rotational velocity,are used to discuss on the two global geodynamic systems in which the intracontinental latitudinal tectonic zone developed.
基金supported by the National Natural Science Foundation of China(71973001).
文摘An intuitive portrayal of the correlation between the carbon and energy markets is essential for risk control and green financial investment management.In this paper,we investigate the asymmetric spillovers between the carbon mar-ket and energy market returns.To achieve that,we improve the Diebold-Yilmaz index model by a time-varying vector autoregressive(TVP-VAR)model.In a unified network,our daily dataset includes the closing prices of the Hubei carbon market,Shenzhen carbon market,coal futures,and energy stock index.The findings reveal that both the Hubei and Shen-zhen pilots typically generate net information spillovers on energy futures.In connection with energy stocks,the Hubei carbon market acts as a net receiver,while the Shenzhen carbon market is a net transmitter.Compared with the Hubei pi-lot,the Shenzhen pilot is more tightly connected to the energy markets.Furthermore,the spillovers of the carbon markets exhibit significant asymmetry.In most cases,they have more substantial impacts on the energy markets when the prices of emission allowances rise.The direction and magnitude of asymmetric spillovers across markets vary over time and can be influenced by certain economic or political events.
基金supported by the National Natural Science Foundation of China(6113200291338101+3 种基金91338108)the National S&T Major Project(2011ZX03004-001-01)the Research Fund of Tsinghua University(2011Z05117)the Co-innovation Laboratory of Aerospace Broadband Network Technology
文摘Due to the limited transmission resources for data relay in the tracking and data relay satellite system （TDRSS）, there are many job requirements in busy days which will be discarded in the conventional job scheduling model. Therefore, the improvement of scheduling efficiency in the TDRSS can not only help to increase the resource utilities, but also to reduce the scheduling failure ratio. A model of nonhomogeneous parallel machines scheduling problems with time window （NPM-TW） is firstly built up for the TDRSS, considering the distinct features of the variable preparation time and the nonhomogeneous transmission rates for different types of antennas on each tracking and data relay satellite （TDRS）. Then, an adaptive subsequence adjustment （ASA） framework with evolutionary asymmetric path-relinking （EvAPR） is proposed to solve this problem, in which an asymmetric progressive crossover operation is involved to overcome the local optima by the conventional job inserting methods. The numerical results show that, compared with the classical greedy randomized adaptive search procedure （GRASP） algorithm, the scheduling failure ratio of jobs can be reduced over 11% on average by the proposed ASA with EvAPR.
基金Project(SGZJHZ00HLJS2000871)supported by the State Grid Science and Technology Project,China。
文摘As an essential part of the industrial Internet of Things(IoT)in power systems,the development of advanced metering infrastructure(AMI)facilitates services such as energy monitoring,load forecasting,and demand response.However,there is a growing risk of privacy disclosure with the wide installation of smart meters,for they transmit readings and sensitive data simultaneously.To guarantee the confidentiality of the sensitive information and authenticity of smart meter readings,we proposed a privacy-preserving scheme based on digital watermarking and elliptic-curve cryptography(ECC)asymmetric encryption.The sensitive data are encrypted using the public key and are hidden in the collected readings using digital watermark.Only the authorized user can extract watermark and can decrypt the confidential data using its private key.The proposed method realizes secure end-to-end confidentiality of the sensitive information.It has faster computing speed and can verify the data source and ensure the authenticity of readings.The example results show that the proposed method has little influence on the original data and unauthorized access cannot be completed within a reasonable time.On embedded hardware,the processing speed of the proposed method is better than the existing methods.
基金Projects(52004182,51804110,51904101)supported by the National Natural Science Foundation of ChinaProject(2020JJ5188)supported by the Natural Science Foundation of Hunan Province,China。
文摘The asymmetric semi-circular bend(ASCB)specimen has been proposed to investigate the cracking behavior in different geo and construction materials and attracted the attention of researchers due to its advantages.However,there are few studies on the fracture toughness determination of rock materials.In this work,a series of fracture tests were performed with the ASCB specimens made of granite.The onset of fracture,crack initiation angle and crack propagating trajectory was analyzed in detail combined with several mixed mode fracture criteria.The influence of the crack length on the mode Ⅰ/Ⅱ fracture toughness was studied.A comparison between the fracture toughness ratios predicted by varying criteria and experimental results was conducted.The relationship between experimentally determined crack initiation angles and curves of the generalized maximum tangential stress(GMTS)criterion was obtained.The fracture process of the specimen was recorded with the high-speed camera.The shortcomings of the ASCB specimens for the fracture toughness determination of rock materials were discussed.The results may provide a reference for analysis of mixed mode I and II fracture behavior of brittle materials.
基金supported by the Aerospace Science and Technology Innovation Foundation (CASC0202-3)
文摘This paper proposes a modified centralized shifted Rayleigh filter（MCSRF） algorithm for tracking boost phase of ballistic missile（BM） trajectory with a highly nonlinear dynamical model based on bearings-only.This paper contributes three folds.Firstly,the mathematical model of an MCSRF for multiple passive sensors is derived.Then,minimum entropy based onedimensional optimization search to adaptively adjust the probability of the different filters for real time state estimation is deployed.Finally,the unscented transform（UT） is introduced to resolve the asymmetric state estimation problem.Simulation results show that the proposed algorithm can consecutively track the BM precisely during the boost phase.In comparison with the unscented Kalman filter（UKF） algorithm,the proposed algorithm effectively reduces the tracking position and velocity root mean square（RMS） errors,which will make more sense for early precision interception.
基金Project(TC190H3ZV/2) supported by the National Building Project of Application Demonstration Platform on New Materials Products,China。
文摘Effects of interrupted ageing(T6I6) and asymmetric rolling on microstructures, mechanical properties, and intergranular corrosion(IGC) behaviors of Al-Mg-Si-Zn alloy were investigated. Results showed that the T6 alloy has the lowest strength and the worst IGC resistance, while the T6I6 alloy has higher strength and better IGC resistance.What’ s more, the alloy treated by pre-rolling deformation has higher strength and better IGC resistance;and the alloy treated by the pre-asymmetry rolling achieves the highest strength, the best IGC resistance and lower elongation. The mechanical properties depend on microstructures such as the grain size, texture, dislocation density and precipitation, the grain boundary misorientation and grain boundary microstructure are responsible for the IGC resistance.
基金Project(51105287)supported by the National Natural Science Foundation of ChinaProject(2012BAA08003)supported by the Key Research and Development Project of New Product and New Technology of Hubei Province,ChinaProject(IRT13087)supported by the Progress for Innovative Research Team in University of Ministry of Education of China
文摘The meshing characteristic of asymmetric involute spur gear was studied, the equations of the geometric shape of the asymmetric gear for both sides were deduced, and the equations of contact ratio and the key points of contact were also obtained.Meanwhile, an involute slope modification method considering the effects of static transmission errors was proposed based on the meshing properties. The characteristic of the involute slope modification was analyzed by changing different modification parameters.The mesh stiffness and synthetic mesh stiffness of unmodified and modified asymmetric spur gears were investigated. Furthermore,the spectrums of synthetic mesh stiffness under different modification parameters were compared. Research results showed that the modification parameters influence the meshing performance of gear pairs, and the proposed modification method was feasible to improve the transmission performance of gear pairs with appropriate modification parameters.
基金Project(51974278)supported by the National Natural Science Foundation of ChinaProject(E2018203446)supported by the Natural Science Foundation of Hebei Province Distinguished Young Fund Project,ChinaProject(2018YFA0707303)supported by the National Key Research and Development Project of China。
文摘Unequal diameter twin-roll casting(UDTRC)can improve the formability,surface conditions,and production efficiency during the fabrication of clad strips.Using Fluent software,a numerical simulation is used to study the asymmetric heat transfer characteristics of Cu/Al clad strips fabricated by UDTRC.The effects of roller velocity ratio,Cu strip thickness,and inclination angle on the kissing point position,as well as the entire temperature distribution are obtained.The heat transfer model is established,and the mechanism is discussed.The Cu strip and rollers are found to be the main causes of asymmetric heat transfer,indicating that the roller velocity ratio changes the liquid zone proportion in the molten pool.The Cu strip thickness determines the heat absorption capacity and the variations in thermal resistance between the molten Al and the big roller.The inclination angle of the small roller changes the cooling time of big roller to molten Al.Moreover,the microstructure of Al cladding under different roller velocity ratios is examined.The results show significant grain refinement caused by the shear strain along the thickness direction of Al cladding and the intense heat transfer at the moment of contact between the metal Al cladding and Cu strip.
基金Projects(52072249,51605315)supported by the National Natural Science Foundation of ChinaProject(E2018210052)supported by the Natural Science Foundation of Hebei Province,ChinaProject(TPL1707)supported by the Open Funds for the State Key Laboratory of Traction Power,China。
文摘To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomotive are established.The coupling vibration equations of axle hung motor and wheelset are derived.For the air braking,the influence mechanism of ABSF on the wheel-rail asymmetric motion and force characteristics are discussed.It can be found that if the ABSF is applied in the front wheelset,all the wheelsets move laterally in the same direction.Once the ABSF occurs in the middle or rear one,other wheelsets may move laterally towards the opposite direction.The motion amplitude and direction of all wheelsets strictly depend on the resultant moment of suspension yawing moment and brake shoe asymmetric moment.For the asymmetric braking,the free lateral gap of axle-box could increase the wheelset motion amplitude,but could not change the moving direction.In both the straight line and curve,the ABSF may lead to wheelset misaligning motion,intensify the wheel-rail lateral dynamic interaction and deteriorate wheel-rail contact state.Especially for the steering wheelsets,the asymmetric braking increases the wheelset attack angle significantly,which forms the worst braking condition.
文摘The intention of this investigation is to study the effects of heat transfer and inclined magnetic field on the peristaltic flow of Williamson fluid in an asymmetric channel through porous medium. The governing two-dimensional equations are simplified under the assumption of long wavelength approximation. The simplified equations are solved for the stream function, temperature, and axial pressure gradient by using a regular perturbation method. The expression for pressure rise is computed numerically. The profiles of velocity, pressure gradient, temperature, heat transfer coefficient and stream function are sketched and interpreted for various embedded parameters and also the behavior of stream function for various wave forms is discussed through graphs. It is observed that the peristaltic velocity increases from porous medium to non-porous medium, the magnetic effects have increasing effect on the temperature, and the size of the trapped bolus decreases with the increasing of magnetic effects while the trend is reversed with the increasing of Darcy number. Moreover, limiting solutions of our problem are in close agreement with the corresponding results of the Newtonian fluid model.
基金Projects(51375042,51505026)supported by the National Natural Science Foundation of ChinaProject(201312G02)supported by Yangfan Innovative&Entepreneurial Research Team,ChinaProject(2015M580977)supported by China Postdoctoral Science Foundation
文摘A rigid-plastic finite element method(FEM) simulation model for a multi-wedge cross wedge rolling(MCWR) was developed to analyze an asymmetric stepped shaft. To evaluate the MCWR process and better understand its deformation characteristics, the material flowing mechanisms, temperature distributions, strain and rolling force were analyzed. The correctness of the finite element simulation is experimentally verified. Numerical simulations and experiments led to the following conclusions: when α=36° and β=7.5°, the quality of the work piece can be significantly improved. Finally, the development of the asymmetric stepped shaft is applied to industrial production.
基金Projects(51374069,U1460107) supported by the National Natural Science Foundation of China
文摘AA1060 aluminum foil was rolled from 4 mm to 20 μm by asymmetric rolling without intermediate annealing. The microstructures and textures were investigated. The original coarse grains with an average grain size of 60 μm were refined to fine equiaxed grains with an average grain size of about 500 nm with mainly large grain boundaries. During the rolling, the intensities of copper texture C-{112}<111> and brass texture B-{011}<211> gradually increased, and most crystallites aggregated along the β and τ orientation lines. The orientation intensity reached the maximum value 26 when the foil was rolled to 500 μm, but significantly decreased to 16 when the thickness became 20 μm, and the texture mainly consisted of a rotation cubic texture RC-{100}<011>. With the combined forces including drawing, compressing and shearing, severe plastic deformation was obtained during the asymmetric rolling, promoting dynamic recrystallization at room temperature. Because of a combined force in the deformation zone and shear force along the normal direction, dynamic recrystallization occurs during the asymmetric rolling; therefore, the average grain size is significantly refined. The texture intensity of ultrathin strip first increases, i.e., work hardening, and then decreases mainly because of dynamic recrystallization.
基金Project(2011FZ050) supported by Applied Basic Research Program of Yunnan Provincial Science and Technology Department,ChinaProject(2011J084) supported by Master Program of Yunnan Province Education Department,China
文摘Local inhomogeneity in totally asymmetric simple exclusion processes （TASEPs） with different hopping rates was studied. Many biological and chemical phenomena can be described by these non-equilibrium processes. A simple approximate theory and extensive Monte Carlo computer simulations were used to calculate the steady-state phase diagrams and bulk densities. It is found that the phase diagram for local inhomogeneity in TASEP with different hopping rates p is qualitatively similar to homogeneous models. Interestingly, there is a saturation point pair （a＊, fl＊） for the system, which is decided by parameters p and q. There are three stationary phases in the system, when parameter p is fixed （i.e., p=0.8）, with the increase of the parameter q, the region of LD/LD and HD/HD phase increases and the HD/LD is the only phase which the region shrinks. The analytical results are in good agreement with simulations.
