在传统电力系统向电力信息物理融合系统CPS演变的趋势下,电力信息安全与电网的可靠运行密不可分,若仍将通讯系统视为完全可靠,则难以适应信息化程度较高的电力系统可靠性评估的要求。引入信息物理关联矩阵(CPIM)的方法,在传统配电网可...在传统电力系统向电力信息物理融合系统CPS演变的趋势下,电力信息安全与电网的可靠运行密不可分,若仍将通讯系统视为完全可靠,则难以适应信息化程度较高的电力系统可靠性评估的要求。引入信息物理关联矩阵(CPIM)的方法,在传统配电网可靠性评估方法中考虑信息物理相依失效,并通过拓展后的IEEE Roy Billinton Test System算例,验证所提方法的有效性。基于算例结果分析了配电网自动化程度对可靠性的影响,同时比较了几种典型变电站主接线方式下,信息物理融合对可靠性的影响。结果表明,随着馈线断路器的数量增加,配电网可靠性得到的改善比信息相依失效带来的影响显著的多,证明了配电自动化推广带来的可靠性收益远大于其弊端。展开更多
In order to study the temporal variations of correlations between two time series,a running correlation coefficient(RCC)could be used.An RCC is calculated for a given time window,and the window is then moved sequentia...In order to study the temporal variations of correlations between two time series,a running correlation coefficient(RCC)could be used.An RCC is calculated for a given time window,and the window is then moved sequentially through time.The current calculation method for RCCs is based on the general definition of the Pearson product-moment correlation coefficient,calculated with the data within the time window,which we call the local running correlation coefficient(LRCC).The LRCC is calculated via the two anomalies corresponding to the two local means,meanwhile,the local means also vary.It is cleared up that the LRCC reflects only the correlation between the two anomalies within the time window but fails to exhibit the contributions of the two varying means.To address this problem,two unchanged means obtained from all available data are adopted to calculate an RCC,which is called the synthetic running correlation coefficient(SRCC).When the anomaly variations are dominant,the two RCCs are similar.However,when the variations of the means are dominant,the difference between the two RCCs becomes obvious.The SRCC reflects the correlations of both the anomaly variations and the variations of the means.Therefore,the SRCCs from different time points are intercomparable.A criterion for the superiority of the RCC algorithm is that the average value of the RCC should be close to the global correlation coefficient calculated using all data.The SRCC always meets this criterion,while the LRCC sometimes fails.Therefore,the SRCC is better than the LRCC for running correlations.We suggest using the SRCC to calculate the RCCs.展开更多
Background: Built environments that are designed to provide accessible, attractive, and convenient locales promote regular physical activity(PA).Norway has great variability in its geographic, natural, and built envir...Background: Built environments that are designed to provide accessible, attractive, and convenient locales promote regular physical activity(PA).Norway has great variability in its geographic, natural, and built environment features. Urban areas have well-developed built environment features, whereas the rural areas are less walkable and this may influence the mode of transport. In general, active transport is more common in urban centers. Further, public transportation is more developed in urban areas, whereas motorized transport may be more widespread in the rural areas. Despite this, in Sogn & Fjordane, a rural county in western Norway, high PA levels are frequently observed. Thus, the aims of this study were to(1) explore perceived built environment features and characterize their associations with objectively measured PA levels in Norwegian adults and(2) explore the differences in these correlates between Sogn & Fjordane and the rest of Norway.Methods: In this cross-sectional study, participants used questionnaires to rate perceptions of their built environments, and their PA was objectively measured for 7 consecutive days using the Acti Graph GT1 M accelerometer. There were 972 Norwegian adults who were included in the study. The average age was 46.9 ± 6.5 years and 43.8% of participants were men. Data were analyzed using multiple linear regression.Results: Total PA and moderate-to-vigorous physical activity(MVPA) were both associated with perceived walkability, the community perception score, and active transport for commuting(all p ≤ 0.004). We also observed geographic-area-specific associations: the community perception score was negatively associated with total PA and MVPA in the rest of Norway(p ≤ 0.012) but not in Sogn & Fjordane. Public transport for commuting was positively associated with MVPA in Sogn & Fjordane(p = 0.03) but not in the rest of Norway.Conclusion: Total PA level and MVPA were associated with built environment factors, such as perceptions of community, perceived walkability,and engaging in active transport for commuting. Geographic differences in the PA correlates were observed, and thus, locally customized environmental population approaches aimed at increasing PA levels may be essential complements to individual behavior and lifestyle strategies.Further, objective measures of Norwegian built environments, such as geographic information system data, and validated walk-and bike-scores would advance the field.展开更多
The effect ofthe edge state on the persistent current in quasi-1D mesoscopic rings with a screened interactionwhich exists only between nearest-neighboring particles is studied with the Hartree-Fock approximation. The...The effect ofthe edge state on the persistent current in quasi-1D mesoscopic rings with a screened interactionwhich exists only between nearest-neighboring particles is studied with the Hartree-Fock approximation. The theoreticalvalue of the current magnitude is greatly enhanced by both the edge state and the Coulomb interaction, and pinningthe electrons into a lattice is good for the enhancement if screening happens. In high dimensional systems the screeningeffect can make the interacting range show anisotropy, and create a tendency of gathering for particles with a repulsivepotential.展开更多
The tensile stress-strain curves of NiTi wires are obtained by tensile experiments under different heat treatments. A phenomenological physical model based on hysteresis element method is developed to describe the exp...The tensile stress-strain curves of NiTi wires are obtained by tensile experiments under different heat treatments. A phenomenological physical model based on hysteresis element method is developed to describe the experimentally determined stress-strain curves of shape memory alloy (SMA) wires. Numerical simulations are made. Simulation results show that：(1) a series of unusual changes on physical and mechanical properties of SMA wires occur when martensitic, especially R (rhombohedral) phase transformation emerge. The stress-strain relation of SMA wires is highly non-linear; (2) there are no notable yielding phenomena before NiTi wires are broken; (3) numerical results obtained by the physical model are in good agreement with experimental data.展开更多
The pole position of the σ meson is determined using the recently proposednew unitarization method combined with the two-loop SU(2) X SU(2) chiral perturbation theoryresults. The scattering length parameters and the ...The pole position of the σ meson is determined using the recently proposednew unitarization method combined with the two-loop SU(2) X SU(2) chiral perturbation theoryresults. The scattering length parameters and the effective range parameters predicted by our methodare in good agreement with experimental results. It is found that M_σ = 542 ± 26 ± 39 MeV, Γ_σ= 546 ± 122 ± 25 MeV.展开更多
Quantum correlations in Werner derivatives are studied with two different approaches, i.e., measurement- induced disturbance （MID） [Phys. Rev. A 77 （2008） 022301] and ameliorated MID （AMID） [J, Phys. A 44 （2011...Quantum correlations in Werner derivatives are studied with two different approaches, i.e., measurement- induced disturbance （MID） [Phys. Rev. A 77 （2008） 022301] and ameliorated MID （AMID） [J, Phys. A 44 （2011） 352002]. They are derived via strict deductions with MID while numerically calculated via the measurement optimization with AMID. Interestingly, quantum correlations captured with both approaches are completely coincident. Moreover, some distinct features of the quantum correlations and their underlying physics are exposed via analyses and discussions.展开更多
Quantum correlations in a family of two-qubit separable classical-quantum correlated states are intensively studied with four different approaches, namely, quantum discord [Phys. Rev. Lett. 88 （2002） 017901], measur...Quantum correlations in a family of two-qubit separable classical-quantum correlated states are intensively studied with four different approaches, namely, quantum discord [Phys. Rev. Lett. 88 （2002） 017901], measurement- induced disturbance （MID） [Phys. Rev. A 77 （2008） 022301], ameliorated MID [J. Phys. A： Math. Theor. 44 （2011） 352002] and quantum dissonance [Phys. Rev. Left. 104 （2010） 080501]. Quantum correlations captured with different approaches are compared and discussed so that their three distinct features are exposed.展开更多
The Unruh effect is one of the most fundamental manifestations of the fact that the particle content of a field theory is observer dependent. However, there has been so far no experimental verification of this effect,...The Unruh effect is one of the most fundamental manifestations of the fact that the particle content of a field theory is observer dependent. However, there has been so far no experimental verification of this effect, as the associated temperatures lie far below any observable threshold. Recently, physical phenomena, which are of great experimental challenge, have been investigated by quantum simulations in various fields. Here we perform a proof-of-principle simulation of the evolution of ferrnionic modes under the Unruh effect with a nuclear magnetic resonance （NMR） quantum simulator. By the quantum simulator, we experimentally demonstrate the behavior of Unruh temperature with acceleration, and we fiarther investigate the quantum correlations quantified by quantum discord between two fermionic modes as seen by two relatively accelerated observers. It is shown that the quantum correlations can be created by the Unrtfia effect from the classically correlated states. Our work may provide a promising way to explore the quantum physics of accelerated systems.展开更多
文摘在传统电力系统向电力信息物理融合系统CPS演变的趋势下,电力信息安全与电网的可靠运行密不可分,若仍将通讯系统视为完全可靠,则难以适应信息化程度较高的电力系统可靠性评估的要求。引入信息物理关联矩阵(CPIM)的方法,在传统配电网可靠性评估方法中考虑信息物理相依失效,并通过拓展后的IEEE Roy Billinton Test System算例,验证所提方法的有效性。基于算例结果分析了配电网自动化程度对可靠性的影响,同时比较了几种典型变电站主接线方式下,信息物理融合对可靠性的影响。结果表明,随着馈线断路器的数量增加,配电网可靠性得到的改善比信息相依失效带来的影响显著的多,证明了配电自动化推广带来的可靠性收益远大于其弊端。
基金supported by the Key Program of the National Natural Science Foundation of China (No. 41330960)the Global Change Research Program of China (No. 2015CB953900)
文摘In order to study the temporal variations of correlations between two time series,a running correlation coefficient(RCC)could be used.An RCC is calculated for a given time window,and the window is then moved sequentially through time.The current calculation method for RCCs is based on the general definition of the Pearson product-moment correlation coefficient,calculated with the data within the time window,which we call the local running correlation coefficient(LRCC).The LRCC is calculated via the two anomalies corresponding to the two local means,meanwhile,the local means also vary.It is cleared up that the LRCC reflects only the correlation between the two anomalies within the time window but fails to exhibit the contributions of the two varying means.To address this problem,two unchanged means obtained from all available data are adopted to calculate an RCC,which is called the synthetic running correlation coefficient(SRCC).When the anomaly variations are dominant,the two RCCs are similar.However,when the variations of the means are dominant,the difference between the two RCCs becomes obvious.The SRCC reflects the correlations of both the anomaly variations and the variations of the means.Therefore,the SRCCs from different time points are intercomparable.A criterion for the superiority of the RCC algorithm is that the average value of the RCC should be close to the global correlation coefficient calculated using all data.The SRCC always meets this criterion,while the LRCC sometimes fails.Therefore,the SRCC is better than the LRCC for running correlations.We suggest using the SRCC to calculate the RCCs.
基金supported by the Sogn & Fjordane County Council, Sparebanken Vest–Visjon Vest, the Norwegian Directorate of Health, Norwegian School of Sport Sciences, and Sogn & Fjordane University College
文摘Background: Built environments that are designed to provide accessible, attractive, and convenient locales promote regular physical activity(PA).Norway has great variability in its geographic, natural, and built environment features. Urban areas have well-developed built environment features, whereas the rural areas are less walkable and this may influence the mode of transport. In general, active transport is more common in urban centers. Further, public transportation is more developed in urban areas, whereas motorized transport may be more widespread in the rural areas. Despite this, in Sogn & Fjordane, a rural county in western Norway, high PA levels are frequently observed. Thus, the aims of this study were to(1) explore perceived built environment features and characterize their associations with objectively measured PA levels in Norwegian adults and(2) explore the differences in these correlates between Sogn & Fjordane and the rest of Norway.Methods: In this cross-sectional study, participants used questionnaires to rate perceptions of their built environments, and their PA was objectively measured for 7 consecutive days using the Acti Graph GT1 M accelerometer. There were 972 Norwegian adults who were included in the study. The average age was 46.9 ± 6.5 years and 43.8% of participants were men. Data were analyzed using multiple linear regression.Results: Total PA and moderate-to-vigorous physical activity(MVPA) were both associated with perceived walkability, the community perception score, and active transport for commuting(all p ≤ 0.004). We also observed geographic-area-specific associations: the community perception score was negatively associated with total PA and MVPA in the rest of Norway(p ≤ 0.012) but not in Sogn & Fjordane. Public transport for commuting was positively associated with MVPA in Sogn & Fjordane(p = 0.03) but not in the rest of Norway.Conclusion: Total PA level and MVPA were associated with built environment factors, such as perceptions of community, perceived walkability,and engaging in active transport for commuting. Geographic differences in the PA correlates were observed, and thus, locally customized environmental population approaches aimed at increasing PA levels may be essential complements to individual behavior and lifestyle strategies.Further, objective measures of Norwegian built environments, such as geographic information system data, and validated walk-and bike-scores would advance the field.
文摘The effect ofthe edge state on the persistent current in quasi-1D mesoscopic rings with a screened interactionwhich exists only between nearest-neighboring particles is studied with the Hartree-Fock approximation. The theoreticalvalue of the current magnitude is greatly enhanced by both the edge state and the Coulomb interaction, and pinningthe electrons into a lattice is good for the enhancement if screening happens. In high dimensional systems the screeningeffect can make the interacting range show anisotropy, and create a tendency of gathering for particles with a repulsivepotential.
文摘The tensile stress-strain curves of NiTi wires are obtained by tensile experiments under different heat treatments. A phenomenological physical model based on hysteresis element method is developed to describe the experimentally determined stress-strain curves of shape memory alloy (SMA) wires. Numerical simulations are made. Simulation results show that：(1) a series of unusual changes on physical and mechanical properties of SMA wires occur when martensitic, especially R (rhombohedral) phase transformation emerge. The stress-strain relation of SMA wires is highly non-linear; (2) there are no notable yielding phenomena before NiTi wires are broken; (3) numerical results obtained by the physical model are in good agreement with experimental data.
文摘The pole position of the σ meson is determined using the recently proposednew unitarization method combined with the two-loop SU(2) X SU(2) chiral perturbation theoryresults. The scattering length parameters and the effective range parameters predicted by our methodare in good agreement with experimental results. It is found that M_σ = 542 ± 26 ± 39 MeV, Γ_σ= 546 ± 122 ± 25 MeV.
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos.20103401110007 and 20123401110008the National Natural Science Foundation of China under Grant Nos.11375011,10975001,51072002,and 51272003+1 种基金the Program for Excellent Talents at the University of Guangdong Province(Guangdong Teacher Letter[1010]No.79)the 211 Project of Anhui University
文摘Quantum correlations in Werner derivatives are studied with two different approaches, i.e., measurement- induced disturbance （MID） [Phys. Rev. A 77 （2008） 022301] and ameliorated MID （AMID） [J, Phys. A 44 （2011） 352002]. They are derived via strict deductions with MID while numerically calculated via the measurement optimization with AMID. Interestingly, quantum correlations captured with both approaches are completely coincident. Moreover, some distinct features of the quantum correlations and their underlying physics are exposed via analyses and discussions.
基金Supported by the Specialized Research Fund for the Doctoral Program of Higher Education under Grant No.20103401110007the National Natural Science Foundation of China under Grant Nos.10874122,10975001,51072002,51272003+1 种基金the Program for Excellent Talents at the University of Guangdong,(Guangdong Teacher Letter[1010]No.79)the 211 Project of Anhui University
文摘Quantum correlations in a family of two-qubit separable classical-quantum correlated states are intensively studied with four different approaches, namely, quantum discord [Phys. Rev. Lett. 88 （2002） 017901], measurement- induced disturbance （MID） [Phys. Rev. A 77 （2008） 022301], ameliorated MID [J. Phys. A： Math. Theor. 44 （2011） 352002] and quantum dissonance [Phys. Rev. Left. 104 （2010） 080501]. Quantum correlations captured with different approaches are compared and discussed so that their three distinct features are exposed.
基金the National Key Basic Research Program of China (Grant Nos. 2013CB921800 and 2014CB848700)the National Natural Science Foundation of China (Grant Nos. 11227901, 91021005, 11375167, 11374308, 11104262 and 11275183)the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No. XDB01030400)
文摘The Unruh effect is one of the most fundamental manifestations of the fact that the particle content of a field theory is observer dependent. However, there has been so far no experimental verification of this effect, as the associated temperatures lie far below any observable threshold. Recently, physical phenomena, which are of great experimental challenge, have been investigated by quantum simulations in various fields. Here we perform a proof-of-principle simulation of the evolution of ferrnionic modes under the Unruh effect with a nuclear magnetic resonance （NMR） quantum simulator. By the quantum simulator, we experimentally demonstrate the behavior of Unruh temperature with acceleration, and we fiarther investigate the quantum correlations quantified by quantum discord between two fermionic modes as seen by two relatively accelerated observers. It is shown that the quantum correlations can be created by the Unrtfia effect from the classically correlated states. Our work may provide a promising way to explore the quantum physics of accelerated systems.
