Amorphous alloy(AA)is attracting more and more attention in electrical machines due to its excellent low loss characteristics.This paper overviews advances on AA electrical machines over the last 30 years,with particu...Amorphous alloy(AA)is attracting more and more attention in electrical machines due to its excellent low loss characteristics.This paper overviews advances on AA electrical machines over the last 30 years,with particular reference to new and novel topologies and processing techniques of AA electrical machines and their key technologies.These include current states and trends for radial-flux AA electrical machines,axial-flux AA electrical machines,influences of processing techniques on electrical performance of AA iron cores,the characteristics of loss and vibration and noise of AA core and AA machines,optimum design of AA electrical machines,etc.The paper highlights the application prospects of the AA electrical machines.展开更多
This paper investigates the feasibility of using a Li-Baker detector based on a modulated Gaussian beam to detect gravitational waves in the GHz band.The first-order perturbation photon fluxes(PPF,signal of the detect...This paper investigates the feasibility of using a Li-Baker detector based on a modulated Gaussian beam to detect gravitational waves in the GHz band.The first-order perturbation photon fluxes(PPF,signal of the detector)and the background photon fluxes(BPF,main noise of the detector),which vary with time,and the transverse distance are calculated.The results show that their propagation directions and energy densities are much different in some areas.Apart from BPF,we also consider two other important noises:diffraction noise and shot noise.In the simulation,it is found that the diffraction noise and shot noise are both lower than the signal level.Meanwhile,the main noise(BPF)can be eliminated when the receiving screen is located in certain special transverse areas where the BPF direction is opposite to that of PPF.Thus,the signal to noise ratio(SNR)obtained using our detection method can reach up to 320 in some transverse areas.These results are beneficial for the design of the Li-Baker detector.展开更多
We have observed the macroscopic resonant tunneling of magnetic flux between macroscopically distinct quantum states in a superconducting flux qubit. The dependences of the macroscopic resonant tunneling on the barrie...We have observed the macroscopic resonant tunneling of magnetic flux between macroscopically distinct quantum states in a superconducting flux qubit. The dependences of the macroscopic resonant tunneling on the barrier height of the potential well, the flux bias and the initial state are investigated. Detailed measurements of the tunneling rate as a function of the flux bias reveal the feature of the quantum noise in the superconducting flux qubit.展开更多
Constraint-based models such as flux balance analysis （FBA） are a powerful tool to study biological metabolic networks. Under the hypothesis that cells operate at an optimal growth rate as the result of evolution an...Constraint-based models such as flux balance analysis （FBA） are a powerful tool to study biological metabolic networks. Under the hypothesis that cells operate at an optimal growth rate as the result of evolution and natural selection, this model successfully predicts most cellular behaviours in growth rate. However, the model ignores the fact that cells can change their cellular metabolic states during evolution, leaving optimal metabolic states unstable. Here, we consider all the cellular processes that change metabolic states into a single term‘noise＇, and assume that cells change metabolic states by randomly walking in feasible solution space. By simulating a state of a cell randomly walking in the constrained solution space of metabolic networks, we found that in a noisy environment cells in optimal states tend to travel away from these points. On considering the competition between the noise effect and the growth effect in cell evolution, we found that there exists a trade-off between these two effects. As a result, the population of the cells contains different cellular metabolic states, and the population growth rate is at suboptimal states.展开更多
With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has establishe...With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. The MFL data obtained from seamless pipeline inspection is usually contaminated by the seamless pipe noise （SPN）. SPN can in some cases completely mask MFL signals from certain type of defects, and therefore considerably reduces the detectability of the defect signals. In this paper, a new de-noising algorithm called wavelet domain adaptive filtering is proposed for removing the SPN contained in the MFL data. The new algorithm results from combining the wavelet transform with the adaptive filtering technique. Results from application of the proposed algorithm to the MFL data from field tests show that the proposed algorithm has good performance and considerably improves the detectability of the defect signals in the MFL data.展开更多
This research presents the development of HL-2A neutron yield measurement which includes^(235)U fission chamber and BF_(3)and^(3)He proportional counters.Equivalent noise formula of the radiation detection signal ampl...This research presents the development of HL-2A neutron yield measurement which includes^(235)U fission chamber and BF_(3)and^(3)He proportional counters.Equivalent noise formula of the radiation detection signal amplification system was derived to guide the development of the signal amplification system.Then all detectors were calibrated in situ by using the^(252)C_(f)neutron source.The neutron yield of the HL-2A during neutral beam heating was analyzed.These results indicate that the developed neutron flux diagnostic system can obtain neutron yield results under various experimental conditions of the HL-2A tokamak,and can provide information on neutron yield.展开更多
A stochastic dissipative dynamical system driven by non-Gaussian noise is investigated. A general approximate Fokker-Planck equation of the system is derived through a path-integral approach. Based on the definition o...A stochastic dissipative dynamical system driven by non-Gaussian noise is investigated. A general approximate Fokker-Planck equation of the system is derived through a path-integral approach. Based on the definition of Shannon＇s information entropy, the exact time dependence of entropy flux and entropy production of the system is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculation can be used to interpret the interplay of the dissipative constant and non-Gaussian noise on the entropy flux and entropy production.展开更多
基金the National Natural Science Foundation of China(51307111,51677122)National key research and development program(2016YFB0300503).
文摘Amorphous alloy(AA)is attracting more and more attention in electrical machines due to its excellent low loss characteristics.This paper overviews advances on AA electrical machines over the last 30 years,with particular reference to new and novel topologies and processing techniques of AA electrical machines and their key technologies.These include current states and trends for radial-flux AA electrical machines,axial-flux AA electrical machines,influences of processing techniques on electrical performance of AA iron cores,the characteristics of loss and vibration and noise of AA core and AA machines,optimum design of AA electrical machines,etc.The paper highlights the application prospects of the AA electrical machines.
基金the National Natural Science Foundation of China(12147102)the Youth Science and Technology Innovation Research Team of Sichuan Province,China(21CXTD0038)。
文摘This paper investigates the feasibility of using a Li-Baker detector based on a modulated Gaussian beam to detect gravitational waves in the GHz band.The first-order perturbation photon fluxes(PPF,signal of the detector)and the background photon fluxes(BPF,main noise of the detector),which vary with time,and the transverse distance are calculated.The results show that their propagation directions and energy densities are much different in some areas.Apart from BPF,we also consider two other important noises:diffraction noise and shot noise.In the simulation,it is found that the diffraction noise and shot noise are both lower than the signal level.Meanwhile,the main noise(BPF)can be eliminated when the receiving screen is located in certain special transverse areas where the BPF direction is opposite to that of PPF.Thus,the signal to noise ratio(SNR)obtained using our detection method can reach up to 320 in some transverse areas.These results are beneficial for the design of the Li-Baker detector.
基金Project supported by the New Century Excellent Talents in University,Chinathe National Natural Science Foundation of China(Grant Nos. 11074114 and 10874074)the National Basic Research Program of China (Grant No. 2011CBA00200)
文摘We have observed the macroscopic resonant tunneling of magnetic flux between macroscopically distinct quantum states in a superconducting flux qubit. The dependences of the macroscopic resonant tunneling on the barrier height of the potential well, the flux bias and the initial state are investigated. Detailed measurements of the tunneling rate as a function of the flux bias reveal the feature of the quantum noise in the superconducting flux qubit.
基金Project supported by the National Natural Science Foundation of China (Grant No 10721403)the MOST of China (Grant No2009CB918500)the National Basic Research Program of China (Grant Nos 2006CB910706 and 2007CB814800)
文摘Constraint-based models such as flux balance analysis （FBA） are a powerful tool to study biological metabolic networks. Under the hypothesis that cells operate at an optimal growth rate as the result of evolution and natural selection, this model successfully predicts most cellular behaviours in growth rate. However, the model ignores the fact that cells can change their cellular metabolic states during evolution, leaving optimal metabolic states unstable. Here, we consider all the cellular processes that change metabolic states into a single term‘noise＇, and assume that cells change metabolic states by randomly walking in feasible solution space. By simulating a state of a cell randomly walking in the constrained solution space of metabolic networks, we found that in a noisy environment cells in optimal states tend to travel away from these points. On considering the competition between the noise effect and the growth effect in cell evolution, we found that there exists a trade-off between these two effects. As a result, the population of the cells contains different cellular metabolic states, and the population growth rate is at suboptimal states.
文摘With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. The MFL data obtained from seamless pipeline inspection is usually contaminated by the seamless pipe noise （SPN）. SPN can in some cases completely mask MFL signals from certain type of defects, and therefore considerably reduces the detectability of the defect signals. In this paper, a new de-noising algorithm called wavelet domain adaptive filtering is proposed for removing the SPN contained in the MFL data. The new algorithm results from combining the wavelet transform with the adaptive filtering technique. Results from application of the proposed algorithm to the MFL data from field tests show that the proposed algorithm has good performance and considerably improves the detectability of the defect signals in the MFL data.
基金partially supported by the Science&Technology Department of Sichuan Province in China (No.2021YFSY0018)National Natural Science Foundation of China (No.11675049).
文摘This research presents the development of HL-2A neutron yield measurement which includes^(235)U fission chamber and BF_(3)and^(3)He proportional counters.Equivalent noise formula of the radiation detection signal amplification system was derived to guide the development of the signal amplification system.Then all detectors were calibrated in situ by using the^(252)C_(f)neutron source.The neutron yield of the HL-2A during neutral beam heating was analyzed.These results indicate that the developed neutron flux diagnostic system can obtain neutron yield results under various experimental conditions of the HL-2A tokamak,and can provide information on neutron yield.
基金National Natural Science Foundation of China under Grant Nos.10472091,10332030,and 10502042
文摘A stochastic dissipative dynamical system driven by non-Gaussian noise is investigated. A general approximate Fokker-Planck equation of the system is derived through a path-integral approach. Based on the definition of Shannon＇s information entropy, the exact time dependence of entropy flux and entropy production of the system is calculated both in the absence and in the presence of non-equilibrium constraint. The present calculation can be used to interpret the interplay of the dissipative constant and non-Gaussian noise on the entropy flux and entropy production.
