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
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
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
This article deals with a linear classical approach for the robust output reference trajectory tracking control of nonlinear SISO Lagrangian systems with a controllable(fAat)tangent linearization around an operating e...This article deals with a linear classical approach for the robust output reference trajectory tracking control of nonlinear SISO Lagrangian systems with a controllable(fAat)tangent linearization around an operating equilibrium point.An endogenous injections and exogenous feedback(EIEF)approach is proposed,which is naturally equivalent to the generalized propor-tional integral control method and to a robust classical compensation network.It is shown that the EIEF controller is also equivalent,within a frequency domain setting demanding respect for the separation principle,to the reduced order observer based active disturbance rejection control approach.The proposed linear control approach is robust with respect to total dis-turbances and,thus,it is ffective for the linear control of the nonlinear Lagrangian system.An ilustrative nonlinear rotary crane Lagrangian system example,which is non-feedback linearizable,is presented along with digital computer simulations.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
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
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
在全球气候变化与“双碳”目标背景下,能源消耗大、排放强度高的平板玻璃企业急需实现绿色低碳转型。研究首先界定平板玻璃企业绿色低碳转型的内涵,识别出技术、能源、资源、经济与管理五大核心维度,并基于文献分析法系统梳理了22个关...在全球气候变化与“双碳”目标背景下,能源消耗大、排放强度高的平板玻璃企业急需实现绿色低碳转型。研究首先界定平板玻璃企业绿色低碳转型的内涵,识别出技术、能源、资源、经济与管理五大核心维度,并基于文献分析法系统梳理了22个关键影响因素。其次,引入决策试验和评价试验法(Decision Making Trial and Evaluation Laboratory,DEMATEL)方法刻画因素间的因果关系,识别关键驱动因素。最后,使用Vensim PLE软件构建系统动力学模型,并验证合理性与有效性。此外,研究围绕五大核心维度设计生产技术改进、能源结构优化、资源优化配置、绿色价值提升、管理调整升级5条转型路径,对现有路径与综合调整路径共七类路径情景开展仿真模拟。仿真结果显示:各路径对转型均具有正向作用,同时与单一路径相比,综合调整路径更能促进绿色低碳转型,且该路径下绿色低碳转型指数增长了55.15%;在转型初期,能源结构优化路径作用显著;长期来看,生产技术改进路径发挥关键作用,后期对综合调整路径的贡献率高达49.43%。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 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.
基金The work of M.A.Aguilar-Orduia and B.C.Gomez-Leon was supported by Consejo Nacional de Ciencia y Tec-nologia(CONACYT)Mexico under Scholarship Grants no.702805 and no.1039577,respectively.
文摘This article deals with a linear classical approach for the robust output reference trajectory tracking control of nonlinear SISO Lagrangian systems with a controllable(fAat)tangent linearization around an operating equilibrium point.An endogenous injections and exogenous feedback(EIEF)approach is proposed,which is naturally equivalent to the generalized propor-tional integral control method and to a robust classical compensation network.It is shown that the EIEF controller is also equivalent,within a frequency domain setting demanding respect for the separation principle,to the reduced order observer based active disturbance rejection control approach.The proposed linear control approach is robust with respect to total dis-turbances and,thus,it is ffective for the linear control of the nonlinear Lagrangian system.An ilustrative nonlinear rotary crane Lagrangian system example,which is non-feedback linearizable,is presented along with digital computer simulations.
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.
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.
文摘在全球气候变化与“双碳”目标背景下,能源消耗大、排放强度高的平板玻璃企业急需实现绿色低碳转型。研究首先界定平板玻璃企业绿色低碳转型的内涵,识别出技术、能源、资源、经济与管理五大核心维度,并基于文献分析法系统梳理了22个关键影响因素。其次,引入决策试验和评价试验法(Decision Making Trial and Evaluation Laboratory,DEMATEL)方法刻画因素间的因果关系,识别关键驱动因素。最后,使用Vensim PLE软件构建系统动力学模型,并验证合理性与有效性。此外,研究围绕五大核心维度设计生产技术改进、能源结构优化、资源优化配置、绿色价值提升、管理调整升级5条转型路径,对现有路径与综合调整路径共七类路径情景开展仿真模拟。仿真结果显示:各路径对转型均具有正向作用,同时与单一路径相比,综合调整路径更能促进绿色低碳转型,且该路径下绿色低碳转型指数增长了55.15%;在转型初期,能源结构优化路径作用显著;长期来看,生产技术改进路径发挥关键作用,后期对综合调整路径的贡献率高达49.43%。
