To find the optimal operational condition when the properties of feedstock changes in the cracking furnace online,a hybrid algorithm named differential evolution group search optimization(DEGSO) is proposed,which is b...To find the optimal operational condition when the properties of feedstock changes in the cracking furnace online,a hybrid algorithm named differential evolution group search optimization(DEGSO) is proposed,which is based on the differential evolution(DE) and the group search optimization(GSO).The DEGSO combines the advantages of the two algorithms:the high computing speed of DE and the good performance of the GSO for preventing the best particle from converging to local optimum.A cooperative method is also proposed for switching between these two algorithms.If the fitness value of one algorithm keeps invariant in several generations and less than the preset threshold,it is considered to fall into the local optimization and the other algorithm is chosen.Experiments on benchmark functions show that the hybrid algorithm outperforms GSO in accuracy,global searching ability and efficiency.The optimization of ethylene and propylene yields is illustrated as a case by DEGSO.After optimization,the yield of ethylene and propylene is increased remarkably,which provides the proper operational condition of the ethylene cracking furnace.展开更多
Data-driven soft sensor is an effective solution to provide rapid and reliable estimations for key quality variables online. The secondary variables affect the primary variable in considerably different speed, and sof...Data-driven soft sensor is an effective solution to provide rapid and reliable estimations for key quality variables online. The secondary variables affect the primary variable in considerably different speed, and soft sensor systems exhibit multi-dynamic characteristics. Thus, the first contribution is improving the model in the previous study with multi-time-constant. The characteristics-separation-based model will be identified in substep way,and the stochastic Newton recursive(SNR) algorithm is adopted. Considering the dual-rate characteristics of soft sensor systems, the proposed model cannot be identified directly. Thus, two auxiliary models are first proposed to offer the intersample estimations at each update period, based on which the improved algorithm(DAM-SNR) is derived. These two auxiliary models function in switching mechanism which has been illustrated in detail. This algorithm serves for the identification of the proposed model together with the SNR algorithm, and the identification procedure is then presented. Finally, the laboratorial case confirms the effectiveness of the proposed soft sensor model and the algorithms.展开更多
The effect of the secondary flow on the starting pressure of a second-throat supersonic ejector has been investigated by adapting the height of the secondary flow inlet.The obtained results show that an optimum value ...The effect of the secondary flow on the starting pressure of a second-throat supersonic ejector has been investigated by adapting the height of the secondary flow inlet.The obtained results show that an optimum value of the secondary inlet height exists,and the starting pressure of the ejector becomes a minimum at that condition.Based on the results of the pressure measurements,a qualitative analysis has been made to clarify the flow behavior and the physical meaning of the performance diagram.It appears that the choking phenomenon of the secondary flow plays an important role in the starting process of the ejector.When the secondary inlet height is relatively small,the choked secondary flow and the supersonic primary flow could be employed to protect the static pressure in the suction chamber from being disturbed by the back pressure effect at a certain primary stagnation pressure,which is lower than the starting pressure for the case of the zero-secondary flow.However,as the secondary inlet height increases and exceeds a critical value,the static pressure in the suction chamber rapidly increases,and the starting pressure of the ejector increases accordingly.展开更多
The entanglement between two stationary qubits is a kind of valuable quantum resources in quantum information or quantum network. This paper investigates the time evolution of the entanglement between two atoms,which ...The entanglement between two stationary qubits is a kind of valuable quantum resources in quantum information or quantum network. This paper investigates the time evolution of the entanglement between two atoms,which are initially prepared in the Bell states and each of which interacts with its own cavity field in the identical and non-identical double damping Jaynes-Cummings(J-C) system. It mainly considers the effect of the atomic spontaneous decay Γ and the decay of cavity field κ on the two-qubit entanglement in such system. While causing the decay of entanglement, Γ and κ can also play a positive role in the entanglement evolution, which may imply a way to better control and maintain the entanglement. What is more, the rules governing the transfer of entanglement between two-qubit subsystems in strong coupling regime are finally studied by taking Γ and κ into consideration.展开更多
The concept of‘cirrhosis’is evolving and it is now clear that compensated and decompensated cirrhosis are completely different in terms of prognosis.Furthermore,the term‘advanced chronic liver disease(ACLD)’better...The concept of‘cirrhosis’is evolving and it is now clear that compensated and decompensated cirrhosis are completely different in terms of prognosis.Furthermore,the term‘advanced chronic liver disease(ACLD)’better reflects the continuum of histological changes occurring in the liver,which continue to progress even after cirrhosis has developed,and might regress after removing the etiological factor causing the liver disease.In compensated ACLD,portal hypertension marks the progression to a stage with higher risk of clinical complication and requires an appropriate evaluation and treatment.Invasive tests to diagnose cirrhosis(liver biopsy)and portal hypertension(hepatic venous pressure gradient measurement and endoscopy)remain of crucial importance in several difficult clinical scenarios,but their need can be reduced by using different non-invasive tests in standard cases.Among non-invasive tests,the accepted use,major limitations and major benefits of serum markers of fibrosis,elastography and imaging methods are summarized in the present review.展开更多
基金Supported by the Major State Basic Research Development Program of China（2012CB720500）the National Natural Science Foundation of China（U1162202）,the National Natural Science Foundation of China（61174118）+2 种基金the National High Technology Research and Development Program of China（2012AA040307）Shanghai Key Technologies R＆D program（12dz1125100）the Shanghai Leading Academic Discipline Project（B504）
文摘To find the optimal operational condition when the properties of feedstock changes in the cracking furnace online,a hybrid algorithm named differential evolution group search optimization(DEGSO) is proposed,which is based on the differential evolution(DE) and the group search optimization(GSO).The DEGSO combines the advantages of the two algorithms:the high computing speed of DE and the good performance of the GSO for preventing the best particle from converging to local optimum.A cooperative method is also proposed for switching between these two algorithms.If the fitness value of one algorithm keeps invariant in several generations and less than the preset threshold,it is considered to fall into the local optimization and the other algorithm is chosen.Experiments on benchmark functions show that the hybrid algorithm outperforms GSO in accuracy,global searching ability and efficiency.The optimization of ethylene and propylene yields is illustrated as a case by DEGSO.After optimization,the yield of ethylene and propylene is increased remarkably,which provides the proper operational condition of the ethylene cracking furnace.
基金Supported by the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(2016RCJJ046)the National Basic Research Program of China(2012CB720500)
文摘Data-driven soft sensor is an effective solution to provide rapid and reliable estimations for key quality variables online. The secondary variables affect the primary variable in considerably different speed, and soft sensor systems exhibit multi-dynamic characteristics. Thus, the first contribution is improving the model in the previous study with multi-time-constant. The characteristics-separation-based model will be identified in substep way,and the stochastic Newton recursive(SNR) algorithm is adopted. Considering the dual-rate characteristics of soft sensor systems, the proposed model cannot be identified directly. Thus, two auxiliary models are first proposed to offer the intersample estimations at each update period, based on which the improved algorithm(DAM-SNR) is derived. These two auxiliary models function in switching mechanism which has been illustrated in detail. This algorithm serves for the identification of the proposed model together with the SNR algorithm, and the identification procedure is then presented. Finally, the laboratorial case confirms the effectiveness of the proposed soft sensor model and the algorithms.
文摘The effect of the secondary flow on the starting pressure of a second-throat supersonic ejector has been investigated by adapting the height of the secondary flow inlet.The obtained results show that an optimum value of the secondary inlet height exists,and the starting pressure of the ejector becomes a minimum at that condition.Based on the results of the pressure measurements,a qualitative analysis has been made to clarify the flow behavior and the physical meaning of the performance diagram.It appears that the choking phenomenon of the secondary flow plays an important role in the starting process of the ejector.When the secondary inlet height is relatively small,the choked secondary flow and the supersonic primary flow could be employed to protect the static pressure in the suction chamber from being disturbed by the back pressure effect at a certain primary stagnation pressure,which is lower than the starting pressure for the case of the zero-secondary flow.However,as the secondary inlet height increases and exceeds a critical value,the static pressure in the suction chamber rapidly increases,and the starting pressure of the ejector increases accordingly.
基金Supported by the National Natural Science Foundation of China under Grant No.11504218the Program of State Key Laboratory of Quantum Optics and Quantum Optics Devices No.KF201704
文摘The entanglement between two stationary qubits is a kind of valuable quantum resources in quantum information or quantum network. This paper investigates the time evolution of the entanglement between two atoms,which are initially prepared in the Bell states and each of which interacts with its own cavity field in the identical and non-identical double damping Jaynes-Cummings(J-C) system. It mainly considers the effect of the atomic spontaneous decay Γ and the decay of cavity field κ on the two-qubit entanglement in such system. While causing the decay of entanglement, Γ and κ can also play a positive role in the entanglement evolution, which may imply a way to better control and maintain the entanglement. What is more, the rules governing the transfer of entanglement between two-qubit subsystems in strong coupling regime are finally studied by taking Γ and κ into consideration.
基金Interdisciplinary Grant 2015 of the University of Bern(UniBe-ID 2015).
文摘The concept of‘cirrhosis’is evolving and it is now clear that compensated and decompensated cirrhosis are completely different in terms of prognosis.Furthermore,the term‘advanced chronic liver disease(ACLD)’better reflects the continuum of histological changes occurring in the liver,which continue to progress even after cirrhosis has developed,and might regress after removing the etiological factor causing the liver disease.In compensated ACLD,portal hypertension marks the progression to a stage with higher risk of clinical complication and requires an appropriate evaluation and treatment.Invasive tests to diagnose cirrhosis(liver biopsy)and portal hypertension(hepatic venous pressure gradient measurement and endoscopy)remain of crucial importance in several difficult clinical scenarios,but their need can be reduced by using different non-invasive tests in standard cases.Among non-invasive tests,the accepted use,major limitations and major benefits of serum markers of fibrosis,elastography and imaging methods are summarized in the present review.
