Using a set of numerical experiments from 39 CMIP5 climate models, we project the emergence time for 4?C global warming with respect to pre-industrial levels and associated climate changes under the RCP8.5 greenhouse...Using a set of numerical experiments from 39 CMIP5 climate models, we project the emergence time for 4?C global warming with respect to pre-industrial levels and associated climate changes under the RCP8.5 greenhouse gas concentration scenario. Results show that, according to the 39 models, the median year in which 4?C global warming will occur is 2084.Based on the median results of models that project a 4?C global warming by 2100, land areas will generally exhibit stronger warming than the oceans annually and seasonally, and the strongest enhancement occurs in the Arctic, with the exception of the summer season. Change signals for temperature go outside its natural internal variabilities globally, and the signal-tonoise ratio averages 9.6 for the annual mean and ranges from 6.3 to 7.2 for the seasonal mean over the globe, with the greatest values appearing at low latitudes because of low noise. Decreased precipitation generally occurs in the subtropics, whilst increased precipitation mainly appears at high latitudes. The precipitation changes in most of the high latitudes are greater than the background variability, and the global mean signal-to-noise ratio is 0.5 and ranges from 0.2 to 0.4 for the annual and seasonal means, respectively. Attention should be paid to limiting global warming to 1.5?C, in which case temperature and precipitation will experience a far more moderate change than the natural internal variability. Large inter-model disagreement appears at high latitudes for temperature changes and at mid and low latitudes for precipitation changes. Overall, the intermodel consistency is better for temperature than for precipitation.展开更多
In this paper we prove the existence and uniqueness of time global mild solutions to the Navier-Stokes-Oseen equations,which describes dynamics of incompressible viscous fluid flows passing a translating and rotating ...In this paper we prove the existence and uniqueness of time global mild solutions to the Navier-Stokes-Oseen equations,which describes dynamics of incompressible viscous fluid flows passing a translating and rotating obstacle,in the solenoidal Lorentz space L_(σ,w)^(3)·Besides,boundedness and polynomial stability of these solutions are also shown.展开更多
High-resolution U–Pb(ID-TIMS,baddeleyite)ages are presented for mafic dykes from selected swarms in two important Amazonian regions:the Carajás Province in the east,and the Rio Apa block in the southwest–areas
Purpose The high energy photon source(HEPS)is a 4th generation synchrotron light source under construction by the institute of high energy physics.The accelerator complex consists of a 500-MeV Linac,a full-energy sync...Purpose The high energy photon source(HEPS)is a 4th generation synchrotron light source under construction by the institute of high energy physics.The accelerator complex consists of a 500-MeV Linac,a full-energy synchrotron booster,a 6-GeV synchrotron storage ring(SR),and three e-beam transport lines for injection and extraction among accelerators.A global timing system(GTS)covers the timing needs for all accelerator,beamline,and experiment systems.The GTS is designed to coordinate the injection processes and various measurements and protections.Most systems require that the RMS jitter of the GTS signal is less than 30 ps,while the trigger jitters for the electron gun and SR injection and extraction kickers are less than 10 ps.Method The HEPS GTS is an event-based timing system based on MicroTCA.4 hardware architecture.The MicroTCA.4300 series products from the micro-research Finland Oy are implemented in the HEPS GTS system.Results and conclusions The RMS jitter,integrated from 1 Hz to 10 MHz,of the 166.6 MHz event clock is 5.489 ps.The RMS jitter of TTL outputs is less than 30 ps.This paper reports the design of the HEPS GTS,which satisfies all of the HEPS physics requirements for timing with preliminary test results shown.展开更多
The cluster global time can change in wireless sensor networks due to leader re-elections and node disabilities between two successive synchronizations, which will affect temporal relationships. This paper analyzes cl...The cluster global time can change in wireless sensor networks due to leader re-elections and node disabilities between two successive synchronizations, which will affect temporal relationships. This paper analyzes cluster global time continuity, using global time change models for the node dynamics. The results prove that defining the global time using the cluster average time (AGT) is more stable than defining it using a single node's local time (SGT). With normally distributed clock-parameter assumptions, the AGT change bounds are at most 70.7% of those for the SGT's. The impacts of the initial phase and frequency skew distributions on the global time continuity are also investigated to show that the initial phase variations may strongly influence the continuity. Simulations show that the AGT is more stable with less disabled nodes or larger clusters. The appropriate cluster size is 20-40 when there are less than 15 disabled nodes.展开更多
We consider a SEIR epidemic model with infectious force in latent period and infected period under discontinuous treatment.The treatment rate has at most a finite number of jump discontinuities in every compact interv...We consider a SEIR epidemic model with infectious force in latent period and infected period under discontinuous treatment.The treatment rate has at most a finite number of jump discontinuities in every compact interval.By using Lyapunov theory for discontinuous differential equations and other techniques on non-smooth analysis,the basic reproductive number Ro is proved to be a sharp threshold value which completely determines the dynamics of the model.If Ro<1,then there exists a disease-free equilibrium which is globally stable.If Ro>1,the disease-free equilibrium becomes unstable and there exists an endemic equilibrium which is globally stable.We discuss that the disease will die out in a finite time which is impossible for the corresponding SEIR model with continuous treatment.Furthermore,the numerical simulations indicate that strengthening treatment measure after infective individuals reach some level is beneficial to disease control.展开更多
The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System (GPS) sites from 1998.0 to mid-2009 on the Austr...The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System (GPS) sites from 1998.0 to mid-2009 on the Australian Plate to estimate the best noise model and thereafter obtain the true uncertainties of the velocity, employing the maximum likelihood estimation (MLE) method. MLE was employed to analyze the data in four ways. In the first two analyses, the noise was assumed to be a combination of flicker noise and white noise for the raw time series and spatially filtered time series. In the final two analyses, the spectral indices and amplitudes were simultaneously estimated for a power law noise plus white noise model for the raw time series and spatially filtered time series. We conclude that the noise model of GPS time series in Australia can be best described as the combination of flicker noise and white noise. Velocity uncertainties fall below -0.2 mm/yr when the time span exceeds -9.5 years. A comparison of noise amplitudes and maximum likelihood estimation values between the raw and spatially filtered time series suggests that traditional spatial filtering to remove common-mode errors might not be applicable to the raw time series of this region.展开更多
In this paper we study the local or global(in time)existence of small data solutions to semi-linear fractionalσ-evolution equations with nonlinear memory.Our main goals is to explain on the one hand the influence of ...In this paper we study the local or global(in time)existence of small data solutions to semi-linear fractionalσ-evolution equations with nonlinear memory.Our main goals is to explain on the one hand the influence of the memory term and on the other hand the influence of higher regularity of the data on qualitative properties of solutions.展开更多
This paper studies scale-type stability for neural networks with unbounded time-varying delays and Lipschitz continuous activation functions. Several sufficient conditions for the global exponential stability and glob...This paper studies scale-type stability for neural networks with unbounded time-varying delays and Lipschitz continuous activation functions. Several sufficient conditions for the global exponential stability and global asymptotic stability of such neural networks on time scales are derived. The new results can extend the existing relevant stability results in the previous literatures to cover some general neural networks.展开更多
基金supported by the National Basic Research Program of China (Grant No. 2016YFA0602401)the National Natural Science Foundation of China (Grant No. 41421004)
文摘Using a set of numerical experiments from 39 CMIP5 climate models, we project the emergence time for 4?C global warming with respect to pre-industrial levels and associated climate changes under the RCP8.5 greenhouse gas concentration scenario. Results show that, according to the 39 models, the median year in which 4?C global warming will occur is 2084.Based on the median results of models that project a 4?C global warming by 2100, land areas will generally exhibit stronger warming than the oceans annually and seasonally, and the strongest enhancement occurs in the Arctic, with the exception of the summer season. Change signals for temperature go outside its natural internal variabilities globally, and the signal-tonoise ratio averages 9.6 for the annual mean and ranges from 6.3 to 7.2 for the seasonal mean over the globe, with the greatest values appearing at low latitudes because of low noise. Decreased precipitation generally occurs in the subtropics, whilst increased precipitation mainly appears at high latitudes. The precipitation changes in most of the high latitudes are greater than the background variability, and the global mean signal-to-noise ratio is 0.5 and ranges from 0.2 to 0.4 for the annual and seasonal means, respectively. Attention should be paid to limiting global warming to 1.5?C, in which case temperature and precipitation will experience a far more moderate change than the natural internal variability. Large inter-model disagreement appears at high latitudes for temperature changes and at mid and low latitudes for precipitation changes. Overall, the intermodel consistency is better for temperature than for precipitation.
基金funded by the Vietnam National University,Hanoi(VNU)under project number QG.17.07.
文摘In this paper we prove the existence and uniqueness of time global mild solutions to the Navier-Stokes-Oseen equations,which describes dynamics of incompressible viscous fluid flows passing a translating and rotating obstacle,in the solenoidal Lorentz space L_(σ,w)^(3)·Besides,boundedness and polynomial stability of these solutions are also shown.
文摘High-resolution U–Pb(ID-TIMS,baddeleyite)ages are presented for mafic dykes from selected swarms in two important Amazonian regions:the Carajás Province in the east,and the Rio Apa block in the southwest–areas
基金This work was supported by the High Energy Photon Source(HEPS)project,a major national science and technology infrastructure in Chinasupported by the fund of JSQ2018ZZ03 of the Key Laboratory of Particle Acceleration Physics&Technology,Institute of High Energy Physics,Chinese Academy of Sciences(CAS)and Youth Innovation Promotion Association,CAS(2019016).
文摘Purpose The high energy photon source(HEPS)is a 4th generation synchrotron light source under construction by the institute of high energy physics.The accelerator complex consists of a 500-MeV Linac,a full-energy synchrotron booster,a 6-GeV synchrotron storage ring(SR),and three e-beam transport lines for injection and extraction among accelerators.A global timing system(GTS)covers the timing needs for all accelerator,beamline,and experiment systems.The GTS is designed to coordinate the injection processes and various measurements and protections.Most systems require that the RMS jitter of the GTS signal is less than 30 ps,while the trigger jitters for the electron gun and SR injection and extraction kickers are less than 10 ps.Method The HEPS GTS is an event-based timing system based on MicroTCA.4 hardware architecture.The MicroTCA.4300 series products from the micro-research Finland Oy are implemented in the HEPS GTS system.Results and conclusions The RMS jitter,integrated from 1 Hz to 10 MHz,of the 166.6 MHz event clock is 5.489 ps.The RMS jitter of TTL outputs is less than 30 ps.This paper reports the design of the HEPS GTS,which satisfies all of the HEPS physics requirements for timing with preliminary test results shown.
基金Supported by the National Natural Science Foundation of China(No. 90707002)
文摘The cluster global time can change in wireless sensor networks due to leader re-elections and node disabilities between two successive synchronizations, which will affect temporal relationships. This paper analyzes cluster global time continuity, using global time change models for the node dynamics. The results prove that defining the global time using the cluster average time (AGT) is more stable than defining it using a single node's local time (SGT). With normally distributed clock-parameter assumptions, the AGT change bounds are at most 70.7% of those for the SGT's. The impacts of the initial phase and frequency skew distributions on the global time continuity are also investigated to show that the initial phase variations may strongly influence the continuity. Simulations show that the AGT is more stable with less disabled nodes or larger clusters. The appropriate cluster size is 20-40 when there are less than 15 disabled nodes.
基金supported by the National Nature Science Foundation of China(11271154).
文摘We consider a SEIR epidemic model with infectious force in latent period and infected period under discontinuous treatment.The treatment rate has at most a finite number of jump discontinuities in every compact interval.By using Lyapunov theory for discontinuous differential equations and other techniques on non-smooth analysis,the basic reproductive number Ro is proved to be a sharp threshold value which completely determines the dynamics of the model.If Ro<1,then there exists a disease-free equilibrium which is globally stable.If Ro>1,the disease-free equilibrium becomes unstable and there exists an endemic equilibrium which is globally stable.We discuss that the disease will die out in a finite time which is impossible for the corresponding SEIR model with continuous treatment.Furthermore,the numerical simulations indicate that strengthening treatment measure after infective individuals reach some level is beneficial to disease control.
基金supported by the National Natural Science Foundation of China(Grant Nos.41304007,41074022)the Chinese Universities Scientific Fund(Grant No.121103)+1 种基金the Surveying and Mapping Basic Research Program of the National Administration of Surveying,Mapping and Geoinformation(Grant No.11-02-02)the China Scholarship Council and College of Science of the University of Nevada,Reno
文摘The span of coordinate time series affects the determination of an optimal noise model. We analyzed position data recorded for 10 continuous Global Positioning System (GPS) sites from 1998.0 to mid-2009 on the Australian Plate to estimate the best noise model and thereafter obtain the true uncertainties of the velocity, employing the maximum likelihood estimation (MLE) method. MLE was employed to analyze the data in four ways. In the first two analyses, the noise was assumed to be a combination of flicker noise and white noise for the raw time series and spatially filtered time series. In the final two analyses, the spectral indices and amplitudes were simultaneously estimated for a power law noise plus white noise model for the raw time series and spatially filtered time series. We conclude that the noise model of GPS time series in Australia can be best described as the combination of flicker noise and white noise. Velocity uncertainties fall below -0.2 mm/yr when the time span exceeds -9.5 years. A comparison of noise amplitudes and maximum likelihood estimation values between the raw and spatially filtered time series suggests that traditional spatial filtering to remove common-mode errors might not be applicable to the raw time series of this region.
基金The research of this article is supported by the DAAD,Erasmus+Project between the Hassiba Benbouali University of Chlef(Algeria)and TU Bergakademie Freiberg,2015-1-DE01-KA107-002026
文摘In this paper we study the local or global(in time)existence of small data solutions to semi-linear fractionalσ-evolution equations with nonlinear memory.Our main goals is to explain on the one hand the influence of the memory term and on the other hand the influence of higher regularity of the data on qualitative properties of solutions.
基金supported by National Natural Science Foundation of China under Grant 61573005 and 11361010the Foundation for Young Professors of Jimei Universitythe Foundation of Fujian Higher Education(JA11154,JA11144)
文摘This paper studies scale-type stability for neural networks with unbounded time-varying delays and Lipschitz continuous activation functions. Several sufficient conditions for the global exponential stability and global asymptotic stability of such neural networks on time scales are derived. The new results can extend the existing relevant stability results in the previous literatures to cover some general neural networks.