High voltage is necessary for high energy lithium-ion batteries but difficult to achieve because of the highly deteriorated cyclability of the batteries.A novel strategy is developed to extend cyclability of a high vo...High voltage is necessary for high energy lithium-ion batteries but difficult to achieve because of the highly deteriorated cyclability of the batteries.A novel strategy is developed to extend cyclability of a high voltage lithium-ion battery,LiNi_(0.5)Mn_(1.5)O_(4)/Graphite(LNMO/Graphite)cell,which emphasizes a rational design of an electrolyte additive that can effectively construct protective interphases on anode and cathode and highly eliminate the effect of hydrogen fluoride(HF).5-Trifluoromethylpyridine-trime thyl lithium borate(LTFMP-TMB),is synthesized,featuring with multi-functionalities.Its anion TFMPTMB-tends to be enriched on cathode and can be preferentially oxidized yielding TMB and radical TFMP-.Both TMB and radical TFMP can combine HF and thus eliminate the detrimental effect of HF on cathode,while the TMB dragged on cathode thus takes a preferential oxidation and constructs a protective cathode interphase.On the other hand,LTFMP-TMB is preferentially reduced on anode and constructs a protective anode interphase.Consequently,a small amount of LTFMP-TMB(0.2%)in 1.0 M LiPF6in EC/DEC/EMC(3/2/5,wt%)results in a highly improved cyclability of LNMO/Graphite cell,with the capacity retention enhanced from 52%to 80%after 150 cycles at 0.5 C between 3.5 and 4.8 V.The as-developed strategy provides a model of designing electrolyte additives for improving cyclability of high voltage batteries.展开更多
In the paper,we discuss the development of the multigap resistive plate chamber time-of-fight(TOF)technology and the production of the solenoidal tracker at RHIC(STAR)TOF detector in China at the beginning of the twen...In the paper,we discuss the development of the multigap resistive plate chamber time-of-fight(TOF)technology and the production of the solenoidal tracker at RHIC(STAR)TOF detector in China at the beginning of the twenty-frst century.Subsequently,recent experimental results from the frst beam energy scan program(BES-I)at the Relativistic Heavy Ion Collider(RHIC)pertaining to measurements of collectivity,chirality,criticality,global polarization,strangeness,heavy favor,dilepton and light nuclei productions are reviewed.展开更多
Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not be...Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered yet.Moreover,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy consumption.Optimizing three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making time.To tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and UAVs.Then,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put forward.We formally proved that a stable matching can be achieved by our proposal.Extensive simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness.展开更多
A new compact torus injector(KTX-CTI)has been built for injection experiments on the Keda Torus eXperiment(KTX)reversed field pinch(RFP).The aim is to study the fundamental physics governing the compact torus(CT)centr...A new compact torus injector(KTX-CTI)has been built for injection experiments on the Keda Torus eXperiment(KTX)reversed field pinch(RFP).The aim is to study the fundamental physics governing the compact torus(CT)central fueling processes.In experiments conducted under the sole influence of a 0.1 T toroidal magnetic field,the injected CT successfully penetrated the entire toroidal magnetic field,reaching the inner wall of the KTX vacuum vessel.Upon reaching the inner wall,the CT diffused both radially outward and toroidally within the vessel at a discernible diffusion speed.Moreover,the inherent helicity within the CT induced a modest KTX plasma current of 200 A,consistent with predictions based on helicity conservation.CT injection demonstrated the capability to initiate KTX discharges at low loop voltages,suggesting its potential as a pre-ionization and current startup technique.During RFP discharges featuring CT injection,the central plasma density was found to exceed the Greenwald density limit,with more peaked density profiles,indicating the predominant confinement of CT plasma within the core region of the KTX bulk plasma.展开更多
The dynamic evolution of the charm hadron in hot quark matter was studied in the framework of a multiphase transport(AMPT)model.We first reproduced the open charm hadron D0pT spectrum in Au+Au collisions at √sNN=200 ...The dynamic evolution of the charm hadron in hot quark matter was studied in the framework of a multiphase transport(AMPT)model.We first reproduced the open charm hadron D0pT spectrum in Au+Au collisions at √sNN=200 GeV by triggering the c c production in AMPT,and then the elliptic flow of charm hadrons was described with different parton cascade cross sections.Charm hadron azimuthal angular correlations were proposed,and they are affected by the different parton crosssection parameter applied in the model,which can facilitate our understanding of the loss of collision energy of charm quarks in hot quark medium and can stimulate further experimental studies.展开更多
A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As t...A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As the conventional PID controller is difficult to make the operation temperatures steady, a fuzzy self-tuning PID control algorithm is proposed. The application shows that the algorithm is effective, the operation temperatures of both stages can be controlled steadily, and the operation flexibility and adaptability of the hydrogen recovery unit are enhanced with safety. This study lays a foundation to optimize the control of the membrane separation process and thus ensure the membrane performance.展开更多
Membrane technology has found wide applications in the petrochemical industry, mainly in the purification and recovery of the hydrogen resources. Accurate prediction of the membrane separation performance plays an imp...Membrane technology has found wide applications in the petrochemical industry, mainly in the purification and recovery of the hydrogen resources. Accurate prediction of the membrane separation performance plays an important role in carrying out advanced process control （APC）. For the first time, a soft-sensor model for the membrane separation process has been established based on the radial basis function （RBF） neural networks. The main performance parameters, i.e, permeate hydrogen concentration, permeate gas flux, and residue hydrogen concentration, are estimated quantitatively by measuring the operating temperature, feed-side pressure, permeate-side pressure, residue-side pressure, feed-gas flux, and feed-hydrogen concentration excluding flow structure, membrane parameters, and other compositions. The predicted results can gain the desired effects. The effectiveness of this novel approach lays a foundation for integrating control technology and optimizing the operation of the gas membrane separation process.展开更多
We study the production and angular correlationof charm hadrons in hot and dense matter produced in high-energy nuclear-nuclear collisions within a multiphasetransport model(AMPT).By triggering additional charm-antich...We study the production and angular correlationof charm hadrons in hot and dense matter produced in high-energy nuclear-nuclear collisions within a multiphasetransport model(AMPT).By triggering additional charm-anticharm quark pair production in the AMPT,the modeldescribes the D^0 nuclear modification factor in the low andintermediate pr regions in Au+Au collisions at√VSNN=200 GeV reasonably well.Further exploration of the D^0 pair azimuthal angular correlation for different centralitiesshows clear evolution from low-multiplicity to high-mul-tiplicity events,which is associated with the number ofcharm quark interactions with medium partons duringAMPT transport.展开更多
By implementing an additional heavy quark-antiquark pair production trigger in a multiphase transport(AMPT)model,we study the effect on anisotropy flows of identified particles with a focus on charged particles and qu...By implementing an additional heavy quark-antiquark pair production trigger in a multiphase transport(AMPT)model,we study the effect on anisotropy flows of identified particles with a focus on charged particles and quarkonium(J/ΨandΥ).A systematic increase in the collision rate for active partons in the AMPT model with such an implementation has been observed.It leads to a slight increase of identified particles anisotropy flows as a function of transverse momentum(pT)and rapidity,and gives a better description of the experimental data of elliptic flow toward larger pT.Our approach provides an efficient way to study the heavy quark dynamics in the AMPT model at LHC energies.展开更多
Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was perf...Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was performed just to align the two markers to each endplate of the curve. The Cobb angle on the posteroanterior radiographs of 24 patients clinically diagnosed with adolescent idiopathic scoliosis was measured by three orthopedic surgeons with both standard Cobb method and the new technique, and the time of measurement was recorded. Intraclass correlation coefficients(ICCs) were calculated to assess the reliability of the new method. Results The time for a measurement with the new tool was approximately 10 seconds less than the time that used to finish a measurement with the standard method(P<0.05). The overall mean Cobb angle for the major curve of the 24 patients was 47.8°. The mean overall intraobserver and interobserver ICC was 0.971 and 0.971 for the Cobb method group, while the overall intraobserver ICC and the interobserver was 0.985 and 0.979 for the new tool group. Conclusions The novel Cobb protractor could perform quick measurement and measure almost all forms of radiographs. The Cobb protractor might be an ideal instrument to measure the Cobb angle.展开更多
This paper mainly investigates the coordinated anti-jamming channel access problems in multiuser scenarios where there exists a tracking jammer who senses the spectrum and traces the channel with maximal receiving pow...This paper mainly investigates the coordinated anti-jamming channel access problems in multiuser scenarios where there exists a tracking jammer who senses the spectrum and traces the channel with maximal receiving power.To cope with the challenges brought by the tracking jammer,a multi-leader onefollower anti-jamming Stackelberg(MOAS)game is formulated,which is able to model the complex interactions between users and the tracking jammer.In the proposed game,users act as leaders,chose their channel access strategies and transmit firstly.The tracking jammer acts as the follower,whose objective is to find the optimal jamming strategy at each time slot.Besides,the existence of Stackelberg equilibriums(SEs)is proved,which means users reach Nash Equilibriums(NEs)for each jamming strategy while the jammer finds its best response jamming strategy for the current network access case.An active attraction based anti-jamming channel access(3ACA)algorithm is designed to reach SEs,where jammed users keep their channel access strategies unchanged to create access chances for other users.To enhance the fairness of the system,users will adjust their strategies and relearn after certain time slots to provide access chances for those users who sacrifice themselves to attract the tracking jammer.展开更多
RETAINED foreign bodies in the urinary tract after surgical or diagnostic procedure, named iatrogenic foreign bodies, are rarely reported, though the estimated incidence was as high as 1/1500 cases.1 Prompt and pro...RETAINED foreign bodies in the urinary tract after surgical or diagnostic procedure, named iatrogenic foreign bodies, are rarely reported, though the estimated incidence was as high as 1/1500 cases.1 Prompt and proper retrieval is required due to potential complications. We report a case of iatrogenic foreign body into the bladder.展开更多
Flow rate and temperature are important parameters for design and operation of liquid lead–bismuth(Pb Bi) experimental loop. The PREKY facility was designed to study test technique of flow rate and local temperature ...Flow rate and temperature are important parameters for design and operation of liquid lead–bismuth(Pb Bi) experimental loop. The PREKY facility was designed to study test technique of flow rate and local temperature of Pb Bi loop. In this work, flow rate monitoring of molten Pb Bi was performed, and temperatures of the Pb Bi and pipe surface were measured. The results show that the flow rate of the venturi-nozzle flow meter had an uncertainty of ±5 % in the range of 0.6–2.0 m/s, and the maximum temperature difference between the Pb Bi and pipe surface was about 8 ℃.展开更多
A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfu...A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfully on Keda Torus eXperiment(KTX), a newly constructed, reversed field pinch(RFP) experimental device at the University of Science and Technology of China(USTC). This diagnostic system is a very important tool for the initial KTX operations. It is compact,with an aperture slit replacing the traditional optical lens system. A flexural interference filter is designed to prevent the center wavelength from shifting too much as the increase of angle from vertical incidence. To eliminate the stray light,the interior of the system is covered with the black aluminum foil having a very high absorptivity. Using the Hαemission data, together with the profiles of electron temperature and density obtained from the Langmuir probe, the neutral density profiles have been calculated for KTX plasmas. The rapid response rate and good spatial resolution of this Hαdiagnostic system will be beneficial for many studies in RFP plasma physics.展开更多
A fast radial scanning probe system was constructed for the Keda Torus eXperiment(KTX)to measure the profiles of boundary plasma parameters such as floating potential,electron density,temperature,transport fluxes,etc....A fast radial scanning probe system was constructed for the Keda Torus eXperiment(KTX)to measure the profiles of boundary plasma parameters such as floating potential,electron density,temperature,transport fluxes,etc.The scanning probe system is driven by slow and fast motion mechanisms,corresponding to the stand-by movement of a stepping motor and the fast scanning movement of a high-torque servo-motor,respectively.In fast scanning,the scanner drives the probe radially up to 20 cm at a maximum velocity of 4.0 m s-1.A noncontact magnetic grating ruler with a high spatial resolution of 5μm is used for the displacement measurement.New scanning probe can reach the center of plasmas rapidly.The comparison of plasma floating potential profiles obtained by a fixed radial rake probe and the single scanning probe suggests that the high-speed scanning probe system is reliable for measuring edge plasma parameter profiles on the KTX device.展开更多
A comprehensive dataset from 594 fracturing wells throughout the Duvernay Formation near Fox Creek, Alberta, is collected to quantify the influences of geological, geomechanical, and operational features on the distri...A comprehensive dataset from 594 fracturing wells throughout the Duvernay Formation near Fox Creek, Alberta, is collected to quantify the influences of geological, geomechanical, and operational features on the distribution and magnitude of hydraulic fracturing-induced seismicity. An integrated machine learning-based investigation is conducted to systematically evaluate multiple factors that contribute to induced seismicity. Feature importance indicates that a distance to fault, a distance to basement, minimum principal stress, cumulative fluid injection, initial formation pressure, and the number of fracturing stages are among significant model predictors. Our seismicity prediction map matches the observed spatial seismicity, and the prediction model successfully guides the fracturing job size of a new well to reduce seismicity risks. This study can apply to mitigating potential seismicity risks in other seismicity-frequent regions.展开更多
Lithium-metal battery based on Ni-rich cathode provides high energy density but presents poor cyclic stability due to the unstable electrode/electrolyte interfaces on both cathode and anode.In this work,we report a ne...Lithium-metal battery based on Ni-rich cathode provides high energy density but presents poor cyclic stability due to the unstable electrode/electrolyte interfaces on both cathode and anode.In this work,we report a new strategy to address this issue.It is found that the cyclic stability of Ni-rich/Li battery can be significantly improved by using succinic anhydride(SA) as an electrolyte additive.Specifically,the capacity retention of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/Li cell is improved from 14% to 83% after 200cycles at 1 C between 3.0 and 4.35 V by applying 5% SA.The underlying mechanism of SA contribution is understood by comparing the effects of malic anhydride(MA) and citraconic anhydride(CA), both of which share a similar molecular structure to SA but show different effects.On anode side,SA can but MA and CA cannot form a protective solid electrolyte interphase(SEI) on Li anode.On cathode side,three anhydrides can suppress the formation of hydrogen fluoride from electrolyte oxidation decomposition,but SA behaves best.Typically,MA shows adverse effects on the interface stability of Li anode and NCM811 cathode,which originates from its high acidity.Though the acidity of MA can be mitigated by substituting a methyl for one H atom at its C=C bond,the substituent CA cannot compete with SA in cyclic stability improvement of the cell,because the SEI resulting from CA is not as robust as that from SA,which is related to the binding energy of the SEI components.This understanding reveals the importance of the electrolyte acidity on the Ni-rich cathode and the robustness of the SEI on Li anode,which is helpful for rationally designing new electrolyte additives to further improve the cyclic stability of high-energydensity Ni-rich/Li batteries.展开更多
基金supported by the National Natural Science Foundation of China(22179041)。
文摘High voltage is necessary for high energy lithium-ion batteries but difficult to achieve because of the highly deteriorated cyclability of the batteries.A novel strategy is developed to extend cyclability of a high voltage lithium-ion battery,LiNi_(0.5)Mn_(1.5)O_(4)/Graphite(LNMO/Graphite)cell,which emphasizes a rational design of an electrolyte additive that can effectively construct protective interphases on anode and cathode and highly eliminate the effect of hydrogen fluoride(HF).5-Trifluoromethylpyridine-trime thyl lithium borate(LTFMP-TMB),is synthesized,featuring with multi-functionalities.Its anion TFMPTMB-tends to be enriched on cathode and can be preferentially oxidized yielding TMB and radical TFMP-.Both TMB and radical TFMP can combine HF and thus eliminate the detrimental effect of HF on cathode,while the TMB dragged on cathode thus takes a preferential oxidation and constructs a protective cathode interphase.On the other hand,LTFMP-TMB is preferentially reduced on anode and constructs a protective anode interphase.Consequently,a small amount of LTFMP-TMB(0.2%)in 1.0 M LiPF6in EC/DEC/EMC(3/2/5,wt%)results in a highly improved cyclability of LNMO/Graphite cell,with the capacity retention enhanced from 52%to 80%after 150 cycles at 0.5 C between 3.5 and 4.8 V.The as-developed strategy provides a model of designing electrolyte additives for improving cyclability of high voltage batteries.
基金National Key Research and Development Program of China(No.2022YFA1604900)National Natural Science Foundation of China(No.12025501)Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34000000)。
文摘In the paper,we discuss the development of the multigap resistive plate chamber time-of-fight(TOF)technology and the production of the solenoidal tracker at RHIC(STAR)TOF detector in China at the beginning of the twenty-frst century.Subsequently,recent experimental results from the frst beam energy scan program(BES-I)at the Relativistic Heavy Ion Collider(RHIC)pertaining to measurements of collectivity,chirality,criticality,global polarization,strangeness,heavy favor,dilepton and light nuclei productions are reviewed.
基金supported by the National Natural Science Foundation of China under Grant 62171465。
文摘Many efforts have been devoted to efficient task scheduling in Multi-Unmanned Aerial Vehicle(UAV)edge computing.However,the heterogeneity of UAV computation resource,and the task re-allocating between UAVs have not been fully considered yet.Moreover,most existing works neglect the fact that a task can only be executed on the UAV equipped with its desired service function(SF).In this backdrop,this paper formulates the task scheduling problem as a multi-objective task scheduling problem,which aims at maximizing the task execution success ratio while minimizing the average weighted sum of all tasks’completion time and energy consumption.Optimizing three coupled goals in a realtime manner with the dynamic arrival of tasks hinders us from adopting existing methods,like machine learning-based solutions that require a long training time and tremendous pre-knowledge about the task arrival process,or heuristic-based ones that usually incur a long decision-making time.To tackle this problem in a distributed manner,we establish a matching theory framework,in which three conflicting goals are treated as the preferences of tasks,SFs and UAVs.Then,a Distributed Matching Theory-based Re-allocating(DiMaToRe)algorithm is put forward.We formally proved that a stable matching can be achieved by our proposal.Extensive simulation results show that Di Ma To Re algorithm outperforms benchmark algorithms under diverse parameter settings and has good robustness.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2022YFE03100000 and 2017YFE0301701)National Natural Science Foundation of China(Nos.12375226,11875255,11635008,11375188 and 11975231)the Fundamental Research Funds for the Central Universities(No.wk34200000022)。
文摘A new compact torus injector(KTX-CTI)has been built for injection experiments on the Keda Torus eXperiment(KTX)reversed field pinch(RFP).The aim is to study the fundamental physics governing the compact torus(CT)central fueling processes.In experiments conducted under the sole influence of a 0.1 T toroidal magnetic field,the injected CT successfully penetrated the entire toroidal magnetic field,reaching the inner wall of the KTX vacuum vessel.Upon reaching the inner wall,the CT diffused both radially outward and toroidally within the vessel at a discernible diffusion speed.Moreover,the inherent helicity within the CT induced a modest KTX plasma current of 200 A,consistent with predictions based on helicity conservation.CT injection demonstrated the capability to initiate KTX discharges at low loop voltages,suggesting its potential as a pre-ionization and current startup technique.During RFP discharges featuring CT injection,the central plasma density was found to exceed the Greenwald density limit,with more peaked density profiles,indicating the predominant confinement of CT plasma within the core region of the KTX bulk plasma.
基金partly supported by the Key Research Program of the Chinese Academy of Science(No.XDPB09)the National Natural Science Foundation of China(Nos.11890714,11775288,11421505,and 11520101004)
文摘The dynamic evolution of the charm hadron in hot quark matter was studied in the framework of a multiphase transport(AMPT)model.We first reproduced the open charm hadron D0pT spectrum in Au+Au collisions at √sNN=200 GeV by triggering the c c production in AMPT,and then the elliptic flow of charm hadrons was described with different parton cascade cross sections.Charm hadron azimuthal angular correlations were proposed,and they are affected by the different parton crosssection parameter applied in the model,which can facilitate our understanding of the loss of collision energy of charm quarks in hot quark medium and can stimulate further experimental studies.
文摘A two-staged membrane separation process for hydrogen recovery from refinery gases is introduced. The principle of the gas membrane separation process and the influence of the operation temperatures are analyzed. As the conventional PID controller is difficult to make the operation temperatures steady, a fuzzy self-tuning PID control algorithm is proposed. The application shows that the algorithm is effective, the operation temperatures of both stages can be controlled steadily, and the operation flexibility and adaptability of the hydrogen recovery unit are enhanced with safety. This study lays a foundation to optimize the control of the membrane separation process and thus ensure the membrane performance.
文摘Membrane technology has found wide applications in the petrochemical industry, mainly in the purification and recovery of the hydrogen resources. Accurate prediction of the membrane separation performance plays an important role in carrying out advanced process control （APC）. For the first time, a soft-sensor model for the membrane separation process has been established based on the radial basis function （RBF） neural networks. The main performance parameters, i.e, permeate hydrogen concentration, permeate gas flux, and residue hydrogen concentration, are estimated quantitatively by measuring the operating temperature, feed-side pressure, permeate-side pressure, residue-side pressure, feed-gas flux, and feed-hydrogen concentration excluding flow structure, membrane parameters, and other compositions. The predicted results can gain the desired effects. The effectiveness of this novel approach lays a foundation for integrating control technology and optimizing the operation of the gas membrane separation process.
基金This work was supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB34030200)the National Natural Science Foundation of China(Nos.12025501,11890710,and 11775288)。
文摘We study the production and angular correlationof charm hadrons in hot and dense matter produced in high-energy nuclear-nuclear collisions within a multiphasetransport model(AMPT).By triggering additional charm-anticharm quark pair production in the AMPT,the modeldescribes the D^0 nuclear modification factor in the low andintermediate pr regions in Au+Au collisions at√VSNN=200 GeV reasonably well.Further exploration of the D^0 pair azimuthal angular correlation for different centralitiesshows clear evolution from low-multiplicity to high-mul-tiplicity events,which is associated with the number ofcharm quark interactions with medium partons duringAMPT transport.
基金supported in part by the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB34030200)the Guangdong Major Project of Basic and Applied Basic Research(No. 2020B0301030008)the National Natural Science Foundation of China (Nos. 12025501, 11890710, 11890714, and12147114)
文摘By implementing an additional heavy quark-antiquark pair production trigger in a multiphase transport(AMPT)model,we study the effect on anisotropy flows of identified particles with a focus on charged particles and quarkonium(J/ΨandΥ).A systematic increase in the collision rate for active partons in the AMPT model with such an implementation has been observed.It leads to a slight increase of identified particles anisotropy flows as a function of transverse momentum(pT)and rapidity,and gives a better description of the experimental data of elliptic flow toward larger pT.Our approach provides an efficient way to study the heavy quark dynamics in the AMPT model at LHC energies.
文摘Objective To introduce a novel Cobb protractor and assess its reliability and rapidity for measuring Cobb angle in scoliosis patients. Methods The novel Cobb protractor had two endplate markers. A measurement was performed just to align the two markers to each endplate of the curve. The Cobb angle on the posteroanterior radiographs of 24 patients clinically diagnosed with adolescent idiopathic scoliosis was measured by three orthopedic surgeons with both standard Cobb method and the new technique, and the time of measurement was recorded. Intraclass correlation coefficients(ICCs) were calculated to assess the reliability of the new method. Results The time for a measurement with the new tool was approximately 10 seconds less than the time that used to finish a measurement with the standard method(P<0.05). The overall mean Cobb angle for the major curve of the 24 patients was 47.8°. The mean overall intraobserver and interobserver ICC was 0.971 and 0.971 for the Cobb method group, while the overall intraobserver ICC and the interobserver was 0.985 and 0.979 for the new tool group. Conclusions The novel Cobb protractor could perform quick measurement and measure almost all forms of radiographs. The Cobb protractor might be an ideal instrument to measure the Cobb angle.
文摘This paper mainly investigates the coordinated anti-jamming channel access problems in multiuser scenarios where there exists a tracking jammer who senses the spectrum and traces the channel with maximal receiving power.To cope with the challenges brought by the tracking jammer,a multi-leader onefollower anti-jamming Stackelberg(MOAS)game is formulated,which is able to model the complex interactions between users and the tracking jammer.In the proposed game,users act as leaders,chose their channel access strategies and transmit firstly.The tracking jammer acts as the follower,whose objective is to find the optimal jamming strategy at each time slot.Besides,the existence of Stackelberg equilibriums(SEs)is proved,which means users reach Nash Equilibriums(NEs)for each jamming strategy while the jammer finds its best response jamming strategy for the current network access case.An active attraction based anti-jamming channel access(3ACA)algorithm is designed to reach SEs,where jammed users keep their channel access strategies unchanged to create access chances for other users.To enhance the fairness of the system,users will adjust their strategies and relearn after certain time slots to provide access chances for those users who sacrifice themselves to attract the tracking jammer.
文摘RETAINED foreign bodies in the urinary tract after surgical or diagnostic procedure, named iatrogenic foreign bodies, are rarely reported, though the estimated incidence was as high as 1/1500 cases.1 Prompt and proper retrieval is required due to potential complications. We report a case of iatrogenic foreign body into the bladder.
基金supported by ITER 973 project (Nos. 2014GB112002 and 2014GB116000)Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA03040200)Foundation of President of Hefei Institute of Physical Science (No. YZJJ201328)
文摘Flow rate and temperature are important parameters for design and operation of liquid lead–bismuth(Pb Bi) experimental loop. The PREKY facility was designed to study test technique of flow rate and local temperature of Pb Bi loop. In this work, flow rate monitoring of molten Pb Bi was performed, and temperatures of the Pb Bi and pipe surface were measured. The results show that the flow rate of the venturi-nozzle flow meter had an uncertainty of ±5 % in the range of 0.6–2.0 m/s, and the maximum temperature difference between the Pb Bi and pipe surface was about 8 ℃.
基金Project supported by the National Magnetic Confinement Fusion Science Program of China(Grant No.2017YFE0301700)the National Natural Science Foundation of China(Grant No.11635008)
文摘A 10-channel Hα diagnostic system has been designed with the rapid response rate of 300 kHz, spatial resolution of about 40 mm, and overlap between adjacent channels of about 3%, and it has been implemented successfully on Keda Torus eXperiment(KTX), a newly constructed, reversed field pinch(RFP) experimental device at the University of Science and Technology of China(USTC). This diagnostic system is a very important tool for the initial KTX operations. It is compact,with an aperture slit replacing the traditional optical lens system. A flexural interference filter is designed to prevent the center wavelength from shifting too much as the increase of angle from vertical incidence. To eliminate the stray light,the interior of the system is covered with the black aluminum foil having a very high absorptivity. Using the Hαemission data, together with the profiles of electron temperature and density obtained from the Langmuir probe, the neutral density profiles have been calculated for KTX plasmas. The rapid response rate and good spatial resolution of this Hαdiagnostic system will be beneficial for many studies in RFP plasma physics.
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2017YFE0301700)National Natural Science Foundation of China(No.11635008).
文摘A fast radial scanning probe system was constructed for the Keda Torus eXperiment(KTX)to measure the profiles of boundary plasma parameters such as floating potential,electron density,temperature,transport fluxes,etc.The scanning probe system is driven by slow and fast motion mechanisms,corresponding to the stand-by movement of a stepping motor and the fast scanning movement of a high-torque servo-motor,respectively.In fast scanning,the scanner drives the probe radially up to 20 cm at a maximum velocity of 4.0 m s-1.A noncontact magnetic grating ruler with a high spatial resolution of 5μm is used for the displacement measurement.New scanning probe can reach the center of plasmas rapidly.The comparison of plasma floating potential profiles obtained by a fixed radial rake probe and the single scanning probe suggests that the high-speed scanning probe system is reliable for measuring edge plasma parameter profiles on the KTX device.
基金This research has been made possible by contributions from the Natural Sciences and Engineering Research Council(NSERC)/Energi Simulation Industrial Research Chair in Reservoir Simulation and the Alberta Innovates(iCore)Chair in Reservoir ModelingThis research was supported by the Science Foundation of China University of Petroleum,Beijing(No.2462023BJRC001)the National Natural Science Foundation of China Joint Fund Key Support Project(No.U19B6003).
文摘A comprehensive dataset from 594 fracturing wells throughout the Duvernay Formation near Fox Creek, Alberta, is collected to quantify the influences of geological, geomechanical, and operational features on the distribution and magnitude of hydraulic fracturing-induced seismicity. An integrated machine learning-based investigation is conducted to systematically evaluate multiple factors that contribute to induced seismicity. Feature importance indicates that a distance to fault, a distance to basement, minimum principal stress, cumulative fluid injection, initial formation pressure, and the number of fracturing stages are among significant model predictors. Our seismicity prediction map matches the observed spatial seismicity, and the prediction model successfully guides the fracturing job size of a new well to reduce seismicity risks. This study can apply to mitigating potential seismicity risks in other seismicity-frequent regions.
基金supported by the National Natural Science Foundation of China(Grant No.21872058)。
文摘Lithium-metal battery based on Ni-rich cathode provides high energy density but presents poor cyclic stability due to the unstable electrode/electrolyte interfaces on both cathode and anode.In this work,we report a new strategy to address this issue.It is found that the cyclic stability of Ni-rich/Li battery can be significantly improved by using succinic anhydride(SA) as an electrolyte additive.Specifically,the capacity retention of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)/Li cell is improved from 14% to 83% after 200cycles at 1 C between 3.0 and 4.35 V by applying 5% SA.The underlying mechanism of SA contribution is understood by comparing the effects of malic anhydride(MA) and citraconic anhydride(CA), both of which share a similar molecular structure to SA but show different effects.On anode side,SA can but MA and CA cannot form a protective solid electrolyte interphase(SEI) on Li anode.On cathode side,three anhydrides can suppress the formation of hydrogen fluoride from electrolyte oxidation decomposition,but SA behaves best.Typically,MA shows adverse effects on the interface stability of Li anode and NCM811 cathode,which originates from its high acidity.Though the acidity of MA can be mitigated by substituting a methyl for one H atom at its C=C bond,the substituent CA cannot compete with SA in cyclic stability improvement of the cell,because the SEI resulting from CA is not as robust as that from SA,which is related to the binding energy of the SEI components.This understanding reveals the importance of the electrolyte acidity on the Ni-rich cathode and the robustness of the SEI on Li anode,which is helpful for rationally designing new electrolyte additives to further improve the cyclic stability of high-energydensity Ni-rich/Li batteries.
