Systems hosting flat bands offer a powerful platform for exploring strong correlation physics.Theoretically,topological degeneracy arising in systems with non-trivial topological orders on periodic manifolds of non-ze...Systems hosting flat bands offer a powerful platform for exploring strong correlation physics.Theoretically,topological degeneracy arising in systems with non-trivial topological orders on periodic manifolds of non-zero genus can generate ideal flat bands.However,experimental realization of such geometrically engineered systems is very difficult.In this work,we demonstrate that flat planes with strategically patterned hole defects can engineer ideal flat bands.We construct two families of models:singular flat band systems where degeneracy is stabilized by non-contractible loop excitations tied to hole defects and perfectly nested van Hove systems where degeneracy arises from line excitations in momentum space.These models circumvent the need for exotic manifolds while retaining the essential features of topological flat bands.By directly linking defect engineering to degeneracy mechanisms,our results establish a scalable framework for experimentally accessible flat band design.展开更多
This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the ...This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the lateral component of the centrifugal force acting on the tank on the basis of modeling and analyzing the dynamic model of the low-speed steering system.Secondly,we propose a differential-flatness ADRC approach by converting the under-actuated system to a fully driven flat one.Moreover,we prove the differential flatness of the steering system,which facilitates a two-channel ADRC development.Finally,we show that both the states of the flat system and the original under-actuated system can track the reference trajectory.On the external interference condition,the system is observed to re-track the target signal within 2 s.展开更多
Tidal flats and saltmarshes have been a long-standing research focus because of their high socio-economic and ecological values.The evolution of tidal flat-marsh systems is highly complex due to the intertwined proces...Tidal flats and saltmarshes have been a long-standing research focus because of their high socio-economic and ecological values.The evolution of tidal flat-marsh systems is highly complex due to the intertwined processes operating over a variety of spatial and temporal scales.As a traditional research highlight,the role of regular hydrodynamic processes such as tides,waves,and river flows have been explored comprehensively with fruitful outcomes.Over past decades,the changing environment(e.g.,sea level rise,increasing anthropogenic activities,and extreme weather conditions)has attracted more attention with many reported insightful results.More recent advances indicate that biological activities play a critical role in tidal flat-marsh morphodynamics but are still poorly understood.The field of research that connects the bio-logical and physical processes is commonly described as"biogeomorphology"and requires the joint efforts by scientists from multiple dis-ciplines ranging from hydraulics,ecology,and geography to sociology.This review aims to provide a synthesis of the current research status of tidal flat-marsh morphodynamics,with a particular emphasis on the understanding of various processes and feedbacks underlying the devel-opment of morphodynamic models.Some future research needs and challenges are identified to facilitate a more sustainable management strategy for tidal flats and saltmarshes under climate change.展开更多
Underactuated mechanical system has less independent inputs than the degrees of freedom（DOF） of the mechanism. The energy efficiency of this class of mechanical systems is an essential problem in practice. On the ba...Underactuated mechanical system has less independent inputs than the degrees of freedom（DOF） of the mechanism. The energy efficiency of this class of mechanical systems is an essential problem in practice. On the basis of the sufficient and necessary condition that concludes a single input nonlinear system is differentially flat, it is shown that the flat output of the single input underactuated mechanical system can be obtained by finding a smooth output function such that the relative degree of the system equals to the dimension of the state space. If the flat output of the underactuated system can be solved explicitly, and by constructing a smooth curve with satisfying given boundary conditions in fiat output space, an energy efficiency optimization method is proposed for the motion planning of the differentially flat underactuated mechanical systems. The inertia wheel pendulum is used to verify the proposed optimization method, and some numerical simulations show that the presented optimal motion planning method can efficaciously reduce the energy cost for given control tasks.展开更多
Heat and mass transfer analysis of an incompressible, laminar boundary layer over solar flat plate collector evapora- tion systems for tannery effluent (soak liquor) is investigated. The governing equations are solved...Heat and mass transfer analysis of an incompressible, laminar boundary layer over solar flat plate collector evapora- tion systems for tannery effluent (soak liquor) is investigated. The governing equations are solved for various liquid to air velocity ratios. Profiles of velocity, temperature and concentration as well as their gradients are presented. The heat transfer and mass transfer coefficients thus obtained are used to evaluate mass of water evaporated for an inclined fibre-reinforced plastic (FRP) solar flat plate collector (FPC) with and without cover. Comparison of these results with the experimental performance shows encouraging trend of good agreement between them.展开更多
As the technology of IP-core-reused has been widely used, a lot of intellectual property （IP） cores have been embedded in different layers of system-on-chip （SOC）. Although the cycles of development and overhead a...As the technology of IP-core-reused has been widely used, a lot of intellectual property （IP） cores have been embedded in different layers of system-on-chip （SOC）. Although the cycles of development and overhead are reduced by this method, it is a challenge to the SOC test. This paper proposes a scheduling method based on the virtual flattened architecture for hierarchical SOC, which breaks the hierarchical architecture to the virtual flattened one. Moreover, this method has more advantages compared with the traditional one, which tests the parent cores and child cores separately. Finally, the method is verified by the ITC＇02 benchmark, and gives good results that reduce the test time and overhead effectively.展开更多
Based on the effective continuum model,we study alternating-twist multilayer graphene system and emergence of magic angles and flat band topology.All the alternating-twist multilayer graphene system(from triple layers...Based on the effective continuum model,we study alternating-twist multilayer graphene system and emergence of magic angles and flat band topology.All the alternating-twist multilayer graphene system(from triple layers to few layers)are found to have flat bands at magic angles where the area of AA stacking equals n-fold(n is an integer)electron cyclotron area.From the pseudo-Landau-level representation,there is always an isolated Dirac band in the alternating-twist graphene system constructed by odd number of layers.Since each pair of flat bands can be perceived as the zeroth pseudo-Landau-levels in two dimensional Dirac fermions,electron in the flat band pair can feel a pseudo-magnetic field with the same magnitude but the opposite sign.Calculated Chern number for each flat band is+1(or-1)which can be tuned by twisting in the vicinity of magic angles or by gating.The concurrent appearance of strong correlation and band topology of flat bands in the alternating-twist multilayer graphene may pave an avenue for the new understanding of superconductivity observed in triple-layered graphene,and supply a new playground for realizing(quantum)anomalous Hall effect.展开更多
Currently,the manual contact rail measurement that was basically adopted in China has low detection efficiency,poor accuracy and poor stability.In order to improve the function of the system,we propose a non-contact m...Currently,the manual contact rail measurement that was basically adopted in China has low detection efficiency,poor accuracy and poor stability.In order to improve the function of the system,we propose a non-contact measurement method based on the flatness and verticality ruler model.The flatness measurement model was built by employing the string measurement method.In addition,the verticality measurement model was built by the dihedral method to measure the rail comprehensively.By extracting curvature information of feature points,in this system,each laser sensor is used to collect rail profile curves.A large number of three-dimensional point clouds data are generated by the unit quaternion method of coordinate transformation,and the contour curves of the characteristic points of the four laser sensors are matched with the corresponding point sets one to one,and the rail contour splicing is finally completed.The experimental results show that this method has better measurement effect compared with the traditional manual measurement method.展开更多
We investigate the bound state problem in a one-dimensional flat band system with a Coulomb potential.It is found that,in the presence of a Coulomb potential of type I(with three equal diagonal elements),similarly to ...We investigate the bound state problem in a one-dimensional flat band system with a Coulomb potential.It is found that,in the presence of a Coulomb potential of type I(with three equal diagonal elements),similarly to that in the twodimensional case,the flat band could not survive.At the same time,the flat band states are transformed into localized states with a logarithmic singularity near the center position.In addition,the wave function near the origin would collapse for an arbitrarily weak Coulomb potential.Due to the wave function collapses,the eigen-energies for a shifted Coulomb potential depend sensitively on the cut-off parameter.For a Coulomb potential of type II,there exist infinite bound states that are generated from the flat band.Furthermore,when the bound state energy is very near the flat band,the energy is inversely proportional to the natural number,e.g.,E_(n)∝1/n,n=1,2,3,...It is expected that the 1/n energy spectrum could be observed experimentally in the near future.展开更多
The knitting industry CAD/CAM system＇s development needs a solution of computer representation of the designed objects. One of them is a transformation of knitting rows and stitches form knitting pattern and its auto...The knitting industry CAD/CAM system＇s development needs a solution of computer representation of the designed objects. One of them is a transformation of knitting rows and stitches form knitting pattern and its automatic analysis is to control data from the knitting design data. A method of the pattern CAD system including the analyzing and the compiling of the pattern data was developed in this paper. By rasterizing the pattern map, the drafted pattern could be compiled into knitting row data and stitches. The storage format of knitting rows data and stitches data could be defined by analyzing the motion of computerized fiat knitting machine. By reassembling the control data, it could be analyzed into the execute data of the controller in computerized fiat knitting machine. This method mainly focused on the weak areas of multi-needle-bed technology and fully-fashioned knitting technology in inland and could be applied to most of control systems in the master-slave mode. The knitting row data and pattern row data in a ＂ ＊. ptn＂ format file were integrated. Giving a corresponding analytic calculation process of control data and realizing independent development of the upper machine and the lower machine, the final knitting control data not only have low computation and transmission cost but also have fast transfer speeds.展开更多
In this paper,the flatness control technology AnShaper^(TM) for cold-rolling mill and industry application are introduced.AnShaper^(TM) includes;partitioning piezomagnetic shape meter for flatness measurement for cold...In this paper,the flatness control technology AnShaper^(TM) for cold-rolling mill and industry application are introduced.AnShaper^(TM) includes;partitioning piezomagnetic shape meter for flatness measurement for cold-rolling strip;flatness measured signals processing system based on digital signal processing(DSP);flatness feedback control model system based on the control efficiency of flatness control actuators and model adaptive function.The application verifies that strip flatness can meet the need of high quality product by using AnShaperTM.The average flatness quality is about 5Ⅰ-unit and the 0.18 mm ultrathin thickness strip flatness is 10Ⅰ-unit.展开更多
In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two ...In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two transverse slope angles (4° and 6°) for the flat belts were used, in a trial with pigs from 20.61 to 117.83 kg of live weight (LW), and the sample size was 7 pigs per pen, 42 pigs per room. The flat belt was more efficient with 6° than with 4° slope angle (32.65% vs. 29.91% dry matter content of solid fraction during the whole fattening period, respectively;P ° than for the 4° (1.4137 vs. 1.3030, during the whole fattening period;P °, this efficiency was not improved in finishing period -83.40 to 117.83 kg LW (two extractions per day) with regard to the growth period -20.61 to 83.40 kg LW (one extraction per day). Meanwhile, with 4° it did improved. The ventilation system underneath slat seems to play a key role in the obtained results.展开更多
The free-radical retrograde-precipitation (FRRPP) process was recently brought into the quantitative areas of work, based on the discovery of possibility of flat temperature profiles in spherical reactive domain syste...The free-radical retrograde-precipitation (FRRPP) process was recently brought into the quantitative areas of work, based on the discovery of possibility of flat temperature profiles in spherical reactive domain systems. With an approximate decoupling analysis of the energy equation from the component-balance equations, these flat temperature profiles were found to be either stable or unstable. Moreover, resulting evolution of the flat profiles has been found to be expressed analytically through the so-called exponential Integral function, which has been shown to be quantitatively inaccurate during the early times of the process. This work tries to resolve this inaccuracy problem, by comparing the exponential integral results with polynomial approximation and numerical results. The result is that for the stable sys-tem, the linearized treatment of the evolution of flat temperature profiles is valid at the early 30% - 40% in the tem-perature axis, while the remainder of the evolution curve is well-represented by the application of the exponential integral function. For the unstable system, the only thing that can be generalized is that both linear and cubic polynomial approximations are reasonably accurate at very small times and temperatures close to initial values.展开更多
This paper shows the modeling of a solar collective heating system in order to predict the system performances. Two systems are proposed: 1) the first, Solar Direct Hot Water, which is composed of flat plate collector...This paper shows the modeling of a solar collective heating system in order to predict the system performances. Two systems are proposed: 1) the first, Solar Direct Hot Water, which is composed of flat plate collectors and thermal storage tank, 2) the second, a Solar Indirect Hot Water in which we added an external heat exchanger of constant effectiveness to the first system. The mass flow rate by a collector is fixed to 0.04 Kg·s–1 and the total number of collectors is adjusted to 60. For the first system, the maximum average water temperature within the tank in a typical day in summer and annual performances are calculated by varying the number of collectors connected in series. For the second, this paper shows the detailed analysis of water temperature within the storage and annual performances by varying the mass flow rate on the cold side of the heat exchanger and the number of collectors in series on the hot side. It is shown that the stratification within the storage is strongly influenced by mass flow rate and the connections between collectors. It is also demonstrated that the number of collectors that can be connected in series is limited. The optimization of the mass flow rate on cold side of the heat exchanger is seen to be an important factor for the energy saving.展开更多
A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried o...A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried out. The investigation involved a series of experiments on systems with 4 different sizes of thermoelectric generators, and it was tested in 5 different vacuum levels during the steady-state. The detailed experimental investigation provided a substantial amount of data, which revealed that the system performance of both heat and electricity power were improved when the heat lost was minimised. The system’s performance strongly depended on the aspect ratio of the thermoelectric generators. This finding might have a significant impact on the cost of the system by saving the user’s and the manufacturer’s time in examining different TEGs with different aspect ratios in order to get the optimum size optimisation of the hybrid system, as well as reduce the manufacturing cost.展开更多
The commercialization of solid oxide fuel cells depends on the cathode,which possesses both high catalytic activity and a thermal-expansion coefficient(TEC)that aligns with the electrolyte.Although the cobalt-based ca...The commercialization of solid oxide fuel cells depends on the cathode,which possesses both high catalytic activity and a thermal-expansion coefficient(TEC)that aligns with the electrolyte.Although the cobalt-based cathode La_(0.6)Sr_(0.4)CoO_(3)(LSC)offers excellent catalytic performance,its TEC is significantly larger than that of the electrolyte.In this study,we mechanically mix Sm_(0.2)Ce_(0.8)O_(2−δ)(SDC)with LSC to create a composite cathode.By incorporating 50wt%SDC,the TEC decreases significantly from 18.29×10^(−6) to 13.90×10^(−6) K^(−1).Under thermal-shock conditions ranging from room temperature to 800℃,the growth rate of polarization resistance is only 0.658%per cycle,i.e.,merely 49%that of pure LSC.The button cell comprising the LSC-SDC composite cathode operates stably for over 900 h without Sr segregation,with a voltage growth rate of 1.11%/kh.A commercial flat-tube cell(active area:70 cm^(2))compris-ing the LSC-SDC composite cathode delivers 54.8 W at 750℃.The distribution of relaxation-time shows that the non-electrode portion is the main rate-limiting step.This study demonstrates that the LSC-SDC mixture strategy effectively improves the compatibility with the electrolyte while maintaining a high output,thus rendering it a promising commercial cathode material.展开更多
An on-line flatness measurement system for steel plate is designed, and that is the flatness meter. The flatness meter is used in the steel plate production line, which is set up on the connecting roller table between...An on-line flatness measurement system for steel plate is designed, and that is the flatness meter. The flatness meter is used in the steel plate production line, which is set up on the connecting roller table between each single equipment, such as between quenching machine and straightener, ACC and straightener, shear finishing section, finished product blanking area, etc. when the steel plate passes through the flatness meter detection area, the detection system automatically starts the detection equipment, and carries out real-time data acquisition and detection on the steel plate. The laser line is used to irradiate the steel plate. After the image is collected, the position offset of the laser line is calculated by image processing and pre calibrated pixel accuracy, so as to obtain the thickness information of the steel plate to be measured. The shape of the steel plate is evaluated, and the information such as head warping, tail warping, head bucking, tail bucking, edge wave, ship type and crown are obtained.展开更多
Objective: to explore and analyze the effect and value of hospital family joint prevention and treatment system in infant flat head syndrome. Methods: a total of 160 newborns delivered in the obstetrics department of ...Objective: to explore and analyze the effect and value of hospital family joint prevention and treatment system in infant flat head syndrome. Methods: a total of 160 newborns delivered in the obstetrics department of our hospital during the period from January 2020 to June 2021 were selected as the study period, and all newborns were divided into reference group (n80, carrying out routine treatment and nursing) and study group (n80, adding guidance and intervention combined with the hospital family joint prevention and treatment system on a routine basis) by random number table method. Results: there was no significant difference between the two groups in the incidence of flat head syndrome at the age of 3 months, but the probability of flat head syndrome at the age of 6 months in the study group was significantly lower than that in the reference group, and the prognosis satisfaction of neonatal parents was higher. The data comparison showed that the difference was statistically significant (P < 0.05). Conclusion: the effect of the hospital family joint prevention and treatment system applied to infant flat head syndrome is exact, and the earlier it is carried out, the more prominent the long-term effect is, which can significantly reduce the incidence of infant flat head syndrome, and the satisfaction of neonatal parents is high, which has outstanding clinical implementation value.展开更多
With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Sa...With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Safety,and Energy Standardized ISO Management System,NYBELT can produce all kinds of flat transmission belts,roller coverings and conveyor belts applicable to textile,printing&packaging,electronics and other industries.Due to the superior quality and the reasonable prices,we have become well known in providing high quality belting products and excellent service to customers all over the world.Our success in the past gives us the confidence to look into the future with great expectations.展开更多
In a peach orchard in Lyuxiang Town,Jinshan District,Shanghai,youth delegates from 13 countries,officials from the Food and Agriculture Organization of the United Nations(FAO),and agricultural heritage experts were im...In a peach orchard in Lyuxiang Town,Jinshan District,Shanghai,youth delegates from 13 countries,officials from the Food and Agriculture Organization of the United Nations(FAO),and agricultural heritage experts were impressed by sweet and juicy Jinshan flat peaches.Jinshan has a history of flat peach cultivation that spans hundreds of years dating back to the Yuan Dynasty(1271-1368).展开更多
基金supported by the Ministry of Science and Technology(Grant No.2022YFA1403901)the National Natural Science Foundation of China(Grant Nos.12494594,11888101,12174428,and 12504192)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000)the New Cornerstone Investigator Program,the Chinese Academy of Sciences through the Youth Innovation Promotion Association(Grant No.2022YSBR-048)the Shanghai Science and Technology Innovation Action Plan(Grant No.24LZ1400800).
文摘Systems hosting flat bands offer a powerful platform for exploring strong correlation physics.Theoretically,topological degeneracy arising in systems with non-trivial topological orders on periodic manifolds of non-zero genus can generate ideal flat bands.However,experimental realization of such geometrically engineered systems is very difficult.In this work,we demonstrate that flat planes with strategically patterned hole defects can engineer ideal flat bands.We construct two families of models:singular flat band systems where degeneracy is stabilized by non-contractible loop excitations tied to hole defects and perfectly nested van Hove systems where degeneracy arises from line excitations in momentum space.These models circumvent the need for exotic manifolds while retaining the essential features of topological flat bands.By directly linking defect engineering to degeneracy mechanisms,our results establish a scalable framework for experimentally accessible flat band design.
基金supported by the National Natural Science Foundation of China(62422305,62373049).
文摘This paper proposes a differential-fatness-based active disturbance rejection control(ADRC)for high-speed steering control of tracked tank systems.Firstly,a high-speed steering model is established by considering the lateral component of the centrifugal force acting on the tank on the basis of modeling and analyzing the dynamic model of the low-speed steering system.Secondly,we propose a differential-flatness ADRC approach by converting the under-actuated system to a fully driven flat one.Moreover,we prove the differential flatness of the steering system,which facilitates a two-channel ADRC development.Finally,we show that both the states of the flat system and the original under-actuated system can track the reference trajectory.On the external interference condition,the system is observed to re-track the target signal within 2 s.
基金supported by the National Natural Science Foundation of China(Grants No.41976156 and 51925905)the Natural Science Foundation of Jiangsu Province(Grant No.BK20200077)+2 种基金the Nantong Science and Technology Bureau(Grant No.MS 12021083)the Marine Science and Technology Innovation Project of Jiangsu Province(Grant No.JSZRHYKJ202105)the Fundamental Research Funds for the Central Universities(Grant No.B210204022).
文摘Tidal flats and saltmarshes have been a long-standing research focus because of their high socio-economic and ecological values.The evolution of tidal flat-marsh systems is highly complex due to the intertwined processes operating over a variety of spatial and temporal scales.As a traditional research highlight,the role of regular hydrodynamic processes such as tides,waves,and river flows have been explored comprehensively with fruitful outcomes.Over past decades,the changing environment(e.g.,sea level rise,increasing anthropogenic activities,and extreme weather conditions)has attracted more attention with many reported insightful results.More recent advances indicate that biological activities play a critical role in tidal flat-marsh morphodynamics but are still poorly understood.The field of research that connects the bio-logical and physical processes is commonly described as"biogeomorphology"and requires the joint efforts by scientists from multiple dis-ciplines ranging from hydraulics,ecology,and geography to sociology.This review aims to provide a synthesis of the current research status of tidal flat-marsh morphodynamics,with a particular emphasis on the understanding of various processes and feedbacks underlying the devel-opment of morphodynamic models.Some future research needs and challenges are identified to facilitate a more sustainable management strategy for tidal flats and saltmarshes under climate change.
基金supported by National Natural Science Foundation of China (Grant No. 50475177)Beijing Municipal Natural Science Foundation, China (Grant No. 3062009)Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality, China (Grant No. PHR200906107).
文摘Underactuated mechanical system has less independent inputs than the degrees of freedom（DOF） of the mechanism. The energy efficiency of this class of mechanical systems is an essential problem in practice. On the basis of the sufficient and necessary condition that concludes a single input nonlinear system is differentially flat, it is shown that the flat output of the single input underactuated mechanical system can be obtained by finding a smooth output function such that the relative degree of the system equals to the dimension of the state space. If the flat output of the underactuated system can be solved explicitly, and by constructing a smooth curve with satisfying given boundary conditions in fiat output space, an energy efficiency optimization method is proposed for the motion planning of the differentially flat underactuated mechanical systems. The inertia wheel pendulum is used to verify the proposed optimization method, and some numerical simulations show that the presented optimal motion planning method can efficaciously reduce the energy cost for given control tasks.
文摘Heat and mass transfer analysis of an incompressible, laminar boundary layer over solar flat plate collector evapora- tion systems for tannery effluent (soak liquor) is investigated. The governing equations are solved for various liquid to air velocity ratios. Profiles of velocity, temperature and concentration as well as their gradients are presented. The heat transfer and mass transfer coefficients thus obtained are used to evaluate mass of water evaporated for an inclined fibre-reinforced plastic (FRP) solar flat plate collector (FPC) with and without cover. Comparison of these results with the experimental performance shows encouraging trend of good agreement between them.
基金Project supported by the Applied Materials Foundation Project of Science and Technology Commission of Shanghai Mu-nicipality (Grant No.08700741000)the System Design on Chip Project of Science and Technology Commission of Shanghai Municipality (Grant No.08706201000)+1 种基金the Leading Academic Discipline Project of Shanghai Municipal Education Committee(Grant No.J50104)the Innovation Foundation Project of Shanghai University
文摘As the technology of IP-core-reused has been widely used, a lot of intellectual property （IP） cores have been embedded in different layers of system-on-chip （SOC）. Although the cycles of development and overhead are reduced by this method, it is a challenge to the SOC test. This paper proposes a scheduling method based on the virtual flattened architecture for hierarchical SOC, which breaks the hierarchical architecture to the virtual flattened one. Moreover, this method has more advantages compared with the traditional one, which tests the parent cores and child cores separately. Finally, the method is verified by the ITC＇02 benchmark, and gives good results that reduce the test time and overhead effectively.
基金financially supported by the National Natural Science Foundation of China(No.52031014)the Ministry of Science and Technology of China(No.2017YFA0206301)Liaoning Provincial Natural Science Fund(No.2021-MS-006)。
文摘Based on the effective continuum model,we study alternating-twist multilayer graphene system and emergence of magic angles and flat band topology.All the alternating-twist multilayer graphene system(from triple layers to few layers)are found to have flat bands at magic angles where the area of AA stacking equals n-fold(n is an integer)electron cyclotron area.From the pseudo-Landau-level representation,there is always an isolated Dirac band in the alternating-twist graphene system constructed by odd number of layers.Since each pair of flat bands can be perceived as the zeroth pseudo-Landau-levels in two dimensional Dirac fermions,electron in the flat band pair can feel a pseudo-magnetic field with the same magnitude but the opposite sign.Calculated Chern number for each flat band is+1(or-1)which can be tuned by twisting in the vicinity of magic angles or by gating.The concurrent appearance of strong correlation and band topology of flat bands in the alternating-twist multilayer graphene may pave an avenue for the new understanding of superconductivity observed in triple-layered graphene,and supply a new playground for realizing(quantum)anomalous Hall effect.
基金Supported by the National Natural Science Foundation of China(U1831133)Shanghai Natural Science Foundation(17ZR1443500)Baoshan Science and Technology Innovation Special Fund(17-C-21)。
文摘Currently,the manual contact rail measurement that was basically adopted in China has low detection efficiency,poor accuracy and poor stability.In order to improve the function of the system,we propose a non-contact measurement method based on the flatness and verticality ruler model.The flatness measurement model was built by employing the string measurement method.In addition,the verticality measurement model was built by the dihedral method to measure the rail comprehensively.By extracting curvature information of feature points,in this system,each laser sensor is used to collect rail profile curves.A large number of three-dimensional point clouds data are generated by the unit quaternion method of coordinate transformation,and the contour curves of the characteristic points of the four laser sensors are matched with the corresponding point sets one to one,and the rail contour splicing is finally completed.The experimental results show that this method has better measurement effect compared with the traditional manual measurement method.
基金the supports of startup grant from Guangzhou Universitysupported by the National Natural Science Foundation of China(Grant No.11874127)。
文摘We investigate the bound state problem in a one-dimensional flat band system with a Coulomb potential.It is found that,in the presence of a Coulomb potential of type I(with three equal diagonal elements),similarly to that in the twodimensional case,the flat band could not survive.At the same time,the flat band states are transformed into localized states with a logarithmic singularity near the center position.In addition,the wave function near the origin would collapse for an arbitrarily weak Coulomb potential.Due to the wave function collapses,the eigen-energies for a shifted Coulomb potential depend sensitively on the cut-off parameter.For a Coulomb potential of type II,there exist infinite bound states that are generated from the flat band.Furthermore,when the bound state energy is very near the flat band,the energy is inversely proportional to the natural number,e.g.,E_(n)∝1/n,n=1,2,3,...It is expected that the 1/n energy spectrum could be observed experimentally in the near future.
基金National Natureal Science Foundation of China(No.51305076)
文摘The knitting industry CAD/CAM system＇s development needs a solution of computer representation of the designed objects. One of them is a transformation of knitting rows and stitches form knitting pattern and its automatic analysis is to control data from the knitting design data. A method of the pattern CAD system including the analyzing and the compiling of the pattern data was developed in this paper. By rasterizing the pattern map, the drafted pattern could be compiled into knitting row data and stitches. The storage format of knitting rows data and stitches data could be defined by analyzing the motion of computerized fiat knitting machine. By reassembling the control data, it could be analyzed into the execute data of the controller in computerized fiat knitting machine. This method mainly focused on the weak areas of multi-needle-bed technology and fully-fashioned knitting technology in inland and could be applied to most of control systems in the master-slave mode. The knitting row data and pattern row data in a ＂ ＊. ptn＂ format file were integrated. Giving a corresponding analytic calculation process of control data and realizing independent development of the upper machine and the lower machine, the final knitting control data not only have low computation and transmission cost but also have fast transfer speeds.
文摘In this paper,the flatness control technology AnShaper^(TM) for cold-rolling mill and industry application are introduced.AnShaper^(TM) includes;partitioning piezomagnetic shape meter for flatness measurement for cold-rolling strip;flatness measured signals processing system based on digital signal processing(DSP);flatness feedback control model system based on the control efficiency of flatness control actuators and model adaptive function.The application verifies that strip flatness can meet the need of high quality product by using AnShaperTM.The average flatness quality is about 5Ⅰ-unit and the 0.18 mm ultrathin thickness strip flatness is 10Ⅰ-unit.
文摘In this study, the separation and drying efficiency of the excreta, separated into solid and liquid fraction by a flat conveyor belt under a partial slatted floor in a facility for fattening pigs, was determined. Two transverse slope angles (4° and 6°) for the flat belts were used, in a trial with pigs from 20.61 to 117.83 kg of live weight (LW), and the sample size was 7 pigs per pen, 42 pigs per room. The flat belt was more efficient with 6° than with 4° slope angle (32.65% vs. 29.91% dry matter content of solid fraction during the whole fattening period, respectively;P ° than for the 4° (1.4137 vs. 1.3030, during the whole fattening period;P °, this efficiency was not improved in finishing period -83.40 to 117.83 kg LW (two extractions per day) with regard to the growth period -20.61 to 83.40 kg LW (one extraction per day). Meanwhile, with 4° it did improved. The ventilation system underneath slat seems to play a key role in the obtained results.
文摘The free-radical retrograde-precipitation (FRRPP) process was recently brought into the quantitative areas of work, based on the discovery of possibility of flat temperature profiles in spherical reactive domain systems. With an approximate decoupling analysis of the energy equation from the component-balance equations, these flat temperature profiles were found to be either stable or unstable. Moreover, resulting evolution of the flat profiles has been found to be expressed analytically through the so-called exponential Integral function, which has been shown to be quantitatively inaccurate during the early times of the process. This work tries to resolve this inaccuracy problem, by comparing the exponential integral results with polynomial approximation and numerical results. The result is that for the stable sys-tem, the linearized treatment of the evolution of flat temperature profiles is valid at the early 30% - 40% in the tem-perature axis, while the remainder of the evolution curve is well-represented by the application of the exponential integral function. For the unstable system, the only thing that can be generalized is that both linear and cubic polynomial approximations are reasonably accurate at very small times and temperatures close to initial values.
文摘This paper shows the modeling of a solar collective heating system in order to predict the system performances. Two systems are proposed: 1) the first, Solar Direct Hot Water, which is composed of flat plate collectors and thermal storage tank, 2) the second, a Solar Indirect Hot Water in which we added an external heat exchanger of constant effectiveness to the first system. The mass flow rate by a collector is fixed to 0.04 Kg·s–1 and the total number of collectors is adjusted to 60. For the first system, the maximum average water temperature within the tank in a typical day in summer and annual performances are calculated by varying the number of collectors connected in series. For the second, this paper shows the detailed analysis of water temperature within the storage and annual performances by varying the mass flow rate on the cold side of the heat exchanger and the number of collectors in series on the hot side. It is shown that the stratification within the storage is strongly influenced by mass flow rate and the connections between collectors. It is also demonstrated that the number of collectors that can be connected in series is limited. The optimization of the mass flow rate on cold side of the heat exchanger is seen to be an important factor for the energy saving.
文摘A systematic experimental investigation to understand the effect of heat loss and the thermoelectric aspect ratio (cross sectional area and length) on a flat plate solar thermoelectric system performance was carried out. The investigation involved a series of experiments on systems with 4 different sizes of thermoelectric generators, and it was tested in 5 different vacuum levels during the steady-state. The detailed experimental investigation provided a substantial amount of data, which revealed that the system performance of both heat and electricity power were improved when the heat lost was minimised. The system’s performance strongly depended on the aspect ratio of the thermoelectric generators. This finding might have a significant impact on the cost of the system by saving the user’s and the manufacturer’s time in examining different TEGs with different aspect ratios in order to get the optimum size optimisation of the hybrid system, as well as reduce the manufacturing cost.
基金the financial support from the National Natural Science Foundation of China(No.22209191)Ningbo Key R&D Project(No.2023Z155).
文摘The commercialization of solid oxide fuel cells depends on the cathode,which possesses both high catalytic activity and a thermal-expansion coefficient(TEC)that aligns with the electrolyte.Although the cobalt-based cathode La_(0.6)Sr_(0.4)CoO_(3)(LSC)offers excellent catalytic performance,its TEC is significantly larger than that of the electrolyte.In this study,we mechanically mix Sm_(0.2)Ce_(0.8)O_(2−δ)(SDC)with LSC to create a composite cathode.By incorporating 50wt%SDC,the TEC decreases significantly from 18.29×10^(−6) to 13.90×10^(−6) K^(−1).Under thermal-shock conditions ranging from room temperature to 800℃,the growth rate of polarization resistance is only 0.658%per cycle,i.e.,merely 49%that of pure LSC.The button cell comprising the LSC-SDC composite cathode operates stably for over 900 h without Sr segregation,with a voltage growth rate of 1.11%/kh.A commercial flat-tube cell(active area:70 cm^(2))compris-ing the LSC-SDC composite cathode delivers 54.8 W at 750℃.The distribution of relaxation-time shows that the non-electrode portion is the main rate-limiting step.This study demonstrates that the LSC-SDC mixture strategy effectively improves the compatibility with the electrolyte while maintaining a high output,thus rendering it a promising commercial cathode material.
文摘An on-line flatness measurement system for steel plate is designed, and that is the flatness meter. The flatness meter is used in the steel plate production line, which is set up on the connecting roller table between each single equipment, such as between quenching machine and straightener, ACC and straightener, shear finishing section, finished product blanking area, etc. when the steel plate passes through the flatness meter detection area, the detection system automatically starts the detection equipment, and carries out real-time data acquisition and detection on the steel plate. The laser line is used to irradiate the steel plate. After the image is collected, the position offset of the laser line is calculated by image processing and pre calibrated pixel accuracy, so as to obtain the thickness information of the steel plate to be measured. The shape of the steel plate is evaluated, and the information such as head warping, tail warping, head bucking, tail bucking, edge wave, ship type and crown are obtained.
文摘Objective: to explore and analyze the effect and value of hospital family joint prevention and treatment system in infant flat head syndrome. Methods: a total of 160 newborns delivered in the obstetrics department of our hospital during the period from January 2020 to June 2021 were selected as the study period, and all newborns were divided into reference group (n80, carrying out routine treatment and nursing) and study group (n80, adding guidance and intervention combined with the hospital family joint prevention and treatment system on a routine basis) by random number table method. Results: there was no significant difference between the two groups in the incidence of flat head syndrome at the age of 3 months, but the probability of flat head syndrome at the age of 6 months in the study group was significantly lower than that in the reference group, and the prognosis satisfaction of neonatal parents was higher. The data comparison showed that the difference was statistically significant (P < 0.05). Conclusion: the effect of the hospital family joint prevention and treatment system applied to infant flat head syndrome is exact, and the earlier it is carried out, the more prominent the long-term effect is, which can significantly reduce the incidence of infant flat head syndrome, and the satisfaction of neonatal parents is high, which has outstanding clinical implementation value.
文摘With the most advanced and sophisticated technologies and equipment,NYBELT is one of the largest manufacturers of flat transmission belts in the world.Under the Certified Quality,Environment,Occupational Health&Safety,and Energy Standardized ISO Management System,NYBELT can produce all kinds of flat transmission belts,roller coverings and conveyor belts applicable to textile,printing&packaging,electronics and other industries.Due to the superior quality and the reasonable prices,we have become well known in providing high quality belting products and excellent service to customers all over the world.Our success in the past gives us the confidence to look into the future with great expectations.
文摘In a peach orchard in Lyuxiang Town,Jinshan District,Shanghai,youth delegates from 13 countries,officials from the Food and Agriculture Organization of the United Nations(FAO),and agricultural heritage experts were impressed by sweet and juicy Jinshan flat peaches.Jinshan has a history of flat peach cultivation that spans hundreds of years dating back to the Yuan Dynasty(1271-1368).
