In this article we show that any embedded graph has a checkerboard colourable twual,which is equivalent to having a bipartite twual.We also obtain that any Eulerian embedded graph has a checkerboard colourable partial...In this article we show that any embedded graph has a checkerboard colourable twual,which is equivalent to having a bipartite twual.We also obtain that any Eulerian embedded graph has a checkerboard colourable partial Petrial,answering questions posed by Ellis-Monaghan and Moffatt[Trans.Amer.Math.Soc.,364,1529–1569(2012)].展开更多
AIM:To compare the Ishihara test errors scores of colour vision deficiency(CVD)subjects when wearing four different types of red-tinted contact lenses(RCL)that differ in their transmittance as determined using a spect...AIM:To compare the Ishihara test errors scores of colour vision deficiency(CVD)subjects when wearing four different types of red-tinted contact lenses(RCL)that differ in their transmittance as determined using a spectrophotometer.METHODS:Six congenital CVD subjects volunteered to participate in this study.Ishihara plates were used to determine the colour vision errors made,whereas Farnsworth-Munsell 100 Hue test was conducted to determine the total error scores(TES)and type of CVD.Four types of RCL(Types A,B,C and D)were inserted in the non-dominant eye and tested in a randomised manner by a masked operator.Errors scores in Ishihara test were determined at baseline without any contact lens and after wearing the four different RCL.The subjects were then divided into two groups based on the mean TES.RESULTS:Repeated measures ANOVA with Greenhouse-Geisser corrections showed that there was a highly significant effect of RCL type on Ishihara error score[F(2.056,10.282)=30.214,P<0.001].Error scores with RCL Type B were significantly lower than errors made when no lens was worn,and with RCL Type C and Type D(all P<0.001).Error scores with RCL Type B were also lower than those made with RCL Type A,however,they were not significantly different.For subjects with TES values less than 180,RCL type B showed the largest improvement in Ishihara error score(50%)compared to the other three RCLs.RCL type A showed the best performance in TES value of more than 180,with an improvement of 80%in Ishihara score.RCL Type A has the lowest transmittance at the confusion wavelength(450-568 nm),followed by RCL Types B,D and C.CONCLUSION:This study shows that RCL can improve Ishihara error scores.RCL with lower transmission at 450-568 nm and 90%transmittance beyond 637 nm are the most effective.Lenses which could block more light between 550-580 nm are more effective for colour defectives with more severe colour defects.展开更多
Quantitative analysis of colouration is an essential tool for subspecies delimitation but has always posed a challenge in avian taxonomy.In this study on the Chestnut-winged Babbler(Cyanoderma erythropterum)species co...Quantitative analysis of colouration is an essential tool for subspecies delimitation but has always posed a challenge in avian taxonomy.In this study on the Chestnut-winged Babbler(Cyanoderma erythropterum)species complex from tropical Southeast Asia,we made use of colour measurements taken with digital cameras and applied two methodologies—(1)the 75%subspecies rule on quantitative colourimetric variables,and(2)the CIEDE2000 colour distance method to generate phylograms,which has probably never been applied in taxonomy before.Given its large number of described subspecies,many of which have been synonymised in modern taxonomies,the species complex serves as an appropriate model to test subspecies validity.Our data indicate that one synonymised subspecies(C.e.apega),from the islands of Bangka and Belitung,requires re-instalment and recognition,whereas one widely recognised subspecies(C.e.fulviventre),from the Banyak Islands,should be synonymised.Our approach also allowed us to redraw geographic subspecies boundaries.Our work indicates that current subspecies taxonomies of many poorly known tropical species may remain error-ridden and highlights the importance and viability of large-scale taxonomic revisions targeting avian subspecies globally while incorporating quantitative colourimetric approaches.展开更多
This work presents a grounding protection system of the central solenoid model coil(CSMC)of the Comprehensive Research Facility for Fusion Technology(CRAFT).The scheme of neutral point voltage detections has been adop...This work presents a grounding protection system of the central solenoid model coil(CSMC)of the Comprehensive Research Facility for Fusion Technology(CRAFT).The scheme of neutral point voltage detections has been adopted in grounding protection system.Compared with the usual current acquisition,the measurement data is accurate,there is no redundant loop,and the economic benefit is high.In this study,the single-end and double-end grounding fault protections of superconducting magnet coil are analyzed,and the fault voltage and current under different fault conditions are calculated.The simulation model of CSMC magnet grounding fault is established,and the simulation results of the model are basically consistent with the theoretical calculation.Finally,a small capacity experiment platform is used to verify the function of the grounding protection system.The experimental results show that by comparing the neutral fault sampling voltage with the theoretical grounding protection threshold,the grounding protection system can effectively detect different types of grounding faults and transmit signals to the control system to protect the coils of superconducting magnets.展开更多
The negative ion based neutral beam injector(NNBI)with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology(CRAFT)in China.The distributed capacitance of the h...The negative ion based neutral beam injector(NNBI)with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology(CRAFT)in China.The distributed capacitance of the high-voltage components is an important basis for the design of surge suppression devices at CRAFT NNBI.This study conducted calculations of distributed capacitance for the key components,including the high-voltage deck,transmission line and isolation transformer in the power supply system using the finite element method.The relationship between the high-voltage deck(HVD)distributed capacitance and the distance from the wall is discussed.The differences in distributed capacitance and energy storage between noncoaxial and coaxial transmission lines are also debated.Finally,the capacitance between the primary and secondary windings of the-400 kV isolation transformer,as well as between the secondary winding and the oil tank casing,was calculated.展开更多
The electromagnetic turbulence in reversed field pinch(RFP)plasmas exhibits three-dimensional characteristics.Suppression of this turbulence is crucial for enhancing plasma confinement,necessitating control over the e...The electromagnetic turbulence in reversed field pinch(RFP)plasmas exhibits three-dimensional characteristics.Suppression of this turbulence is crucial for enhancing plasma confinement,necessitating control over the electric field or the current profile.To this end,two sets of electrodes have been designed and installed on the Keda Torus eXperiment(KTX)RFP device to manipulate the edge electric field and the edge parallel current profile.Subsequently,the edge radial electric field and edge parallel current profile control experiments are conducted.In the edge radial electric field control experiments,the edge radial electric field is altered under bias,accompanied with an increase in the electron density and plasma duration.However,under bias,both electrostatic and magnetic fluctuations are enhanced.In the edge parallel current profile control experiments,the results indicate that bias modifies the edge parallel current profile locally,leading to a localized increase in the field reversal depth and electron density.Additionally,a reduction in magnetic fluctuations is observed within the reversed field enhanced region under bias,suggesting that the bias suppresses magnetic perturbations.展开更多
When discharge faults occur in dry air switchgear,the air decomposes to produce diverse gases,with NO_(2) reaching the highest levels.Detecting the NO_(2) level can reflect the operation status of the equipment.This p...When discharge faults occur in dry air switchgear,the air decomposes to produce diverse gases,with NO_(2) reaching the highest levels.Detecting the NO_(2) level can reflect the operation status of the equipment.This paper proposes to combine ZnO cluster with MoS_(2) to improve the gassensitive properties of the monolayer.Based on the Density Functional Theory(DFT),the effect of(ZnO)n size on the behavior of MoS_(2 )is considered.Key parameters such as adsorption energy and band gap of(ZnO)n-MoS_(2)/NO_(2) system were calculated.The ZnO-MoS_(2) heterojunction was successfully synthesized by a hydrothermal method.The gas sensor exhibits a remarkable response and a fast response-recovery time to 100 ppm NO_(2).In addition,it demonstrates excellent selectivity,long-term stability and a low detection limit.This work confirms the potential of the ZnO-MoS_(2) composite structure as a highly effective gas sensor for NO_(2) detection,which provides valuable theoretical and experimental insights for fault detection in dry air switchgear.展开更多
The EHL-2 spherical torus at ENN is the next-generation experimental platform under conceptual design,aiming at realizing proton-boron(p-^(11)B)thermonuclear fusion,which is an attractive pathway towards neutron-free ...The EHL-2 spherical torus at ENN is the next-generation experimental platform under conceptual design,aiming at realizing proton-boron(p-^(11)B)thermonuclear fusion,which is an attractive pathway towards neutron-free fusion.To achieve high-performance steady-state plasma,it is extremely necessary to study the turbulence transport characteristics with high boron content in the plasma core.This study investigates the transport properties in the core internal transport barrier(ITB)region of p-^(11)B plasma utilizing the gyrokinetic code GENE in view of the high ion temperature scenario of EHL-2,specifically focusing on the impact of boron fractions and plasmaβon the microinstabilities and corresponding transport features.Numerical findings indicate that the inclusion of boron species effectively suppresses the trapped electron modes(TEMs)as well as promoting a transition from electromagnetic to electrostatic turbulence with increased boron fraction,which is a result of the suppression of microinstabilities by effective charge and mass.Moreover,it has been identified that the external E×B rotational shear has a notable inhibitory influence on transport,which can reduce the transport level by two to three orders of magnitude,especially at medium boron content.The suppressive effect of E×B on turbulence is weakened once the kinetic ballooning mode(KBM)is excited and the transport shows a rapid increase withβtogether with a reduction in zonal flow amplitude,which is consistent with previous findings.Therefore,it is strongly suggested that exploring advanced strategies for mitigating turbulent transport at highβregimes is necessary for the active control of plasma behavior regarding p-^(11)B plasma-based fusion devices such as EHL-2.展开更多
In this study,we explored a one-step direct synthesis of NH3 under mild experimental conditions utilizing pulse-modulated microwave plasma technology at atmospheric pressure.At a substantial gas flow rate,a microwave ...In this study,we explored a one-step direct synthesis of NH3 under mild experimental conditions utilizing pulse-modulated microwave plasma technology at atmospheric pressure.At a substantial gas flow rate,a microwave plasma jet was formed and the microwave-assisted ammonia synthesis can be realized.Impacts of various parameters including the gas flow rate,gas component,microwave absorbed power,pulse modulation frequency,and pulse duty cycle on ammonia synthesis were systematically investigated.To indicate the reaction path of ammonia synthesis,the distributions of both the gas temperature and active species were also studied using optical emission spectra technology.It is found that a considerable amount of ammonia was directly synthesized without involvement of any catalysts,the highest ammonia production rate and energy efficiency(EE),up to 2.93μmol·min^(-1) and 6.64×10^(-2)g·(k W·h)^(-1),respectively,were achieved under low microwave power of 84.42 W.The duty cycle has obvious influences on the synthesis efficiency,compared to a duty cycle of 80%,the ammonia synthesis rate,EE and nitrogen conversion decreased by about 22%at a duty cycle of 100%.This finding underscores the significance of incorporating pulse modulation in the microwave discharge process for ammonia synthesis.Furthermore,it was found that vibrational excitation of microwave plasma has a significant driving effect on ammonia synthesis.展开更多
The phenomenon of shock/shock interaction(SSI)is widely observed in high-speed flow,and the double wedge SSI represents one of the typical problems encountered.The control effect of single-pulse plasma synthetic jet(P...The phenomenon of shock/shock interaction(SSI)is widely observed in high-speed flow,and the double wedge SSI represents one of the typical problems encountered.The control effect of single-pulse plasma synthetic jet(PSJ)on double wedge type-Ⅵand type-ⅤSSI was investigated experimentally and numerically,and the influence of discharge energy was also explored.The findings indicate that the interaction between PSJ and the high-speed freestream results in the formation of a plasma layer and a jet shock,which collectively governs the control of SSI.The control mechanism of single-pulse PSJ on SSI lies in its capacity to attenuate both shock and SSI.For type-ⅥSSI,the original second-wedge oblique shock is eliminated under the control of PSJ,resulting in a new type-ⅥSSI formed by the jet shock and the first-wedge oblique shock.For type-ⅤSSI,the presence of PSJ effectively mitigates the intensity of Mach stem,supersonic jet,and reflected shocks,thereby facilitating its transition into type-ⅥSSI.The numerical results indicate that the peak pressure can be reduced by approximately 32.26%at maximum.Furthermore,the development of PSJ also extends in the Z direction.The pressure decreases in the area affected by both PSJ and jet shock due to the attenuation of the SSI zone.With increasing discharge energy,the control effect of PSJ on SSI is gradually enhanced.展开更多
ENN is planning the next generation experimental device EHL-2 with the goal to verify the thermal reaction rates of p-^(11)B fusion,establish spherical torus/tokamak experimental scaling laws at 10’s keV ion temperat...ENN is planning the next generation experimental device EHL-2 with the goal to verify the thermal reaction rates of p-^(11)B fusion,establish spherical torus/tokamak experimental scaling laws at 10’s keV ion temperature,and provide a design basis for subsequent experiments to test and realize the p-^(11)B fusion burning plasma.Based on 0-dimensional(0-D)system design and 1.5-dimensional transport modelling analyses,the main target parameters of EHL-2 have been basically determined,including the plasma major radius,R0,of 1.05 m,the aspect ratio,A,of 1.85,the maximum central toroidal magnetic field strength,B0,of 3 T,and the plasma toroidal current,Ip,of 3 MA.The main heating system will be the neutral beam injection at a total power of 17 MW.In addition,6 MW of electron cyclotron resonance heating will serve as the main means of local current drive and MHD instabilities control.The physics design of EHL-2 is focused on addressing three main operating scenarios,i.e.,(1)high ion temperature scenario,(2)high-performance steady-state scenario and(3)high triple product scenario.Each scenario will integrate solutions to different important issues,including equilibrium configuration,heating and current drive,confinement and transport,MHD instability,p-^(11)B fusion reaction,plasma-wall interactions,etc.Beyond that,there are several unique and significant challenges to address,including●establish a plasma with extremely high core ion temperature(T_(i,0)>30 keV),and ensure a large ion-to-electron tempera-ture ratio(T_(i,0)/Te,0>2),and a boron concentration of 10%‒15%at the plasma core;●realize the start-up by non-inductive current drive and the rise of MA-level plasma toroidal current.This is because the volt-seconds that the central solenoid of the ST can provide are very limited;●achieve divertor heat and particle fluxes control including complete detachment under high P/R(>20 MW/m)at rela-tively low electron densities.This overview will introduce the advanced progress in the physics design of EHL-2.展开更多
The cylindrical virtual cathode reflex triode is a new type of pulsed hard X-ray load,which has the advantages of simple structure,high radiation conversion efficiency,and simplicity in seriesparallel operation.This p...The cylindrical virtual cathode reflex triode is a new type of pulsed hard X-ray load,which has the advantages of simple structure,high radiation conversion efficiency,and simplicity in seriesparallel operation.This paper presents a method to reduce the impedance of the triode using a multiring cathode.The average electric field on the ring-cathode emission surface is enhanced due to edge effect,and the beam intensity is greatly increased in proportion to the square of the electric field strength.Multi-ring cathode is used to enlarge the emission area.Therefore,the reflex triode can work at lower impedance and generate a stronger beam under the same anode-cathode gap.In addition,the electric field enhancement of the cathode reduces the cathode emission stabilization time and enhances the operation stability of the triode.The effects of parameters such as ring width and ring gap on the triode impedance are simulated and studied.The cathode emission stabilization time and the X-ray conversion efficiency are compared.The design basis of cathode structure parameters and the impedance control method of the cylindrical virtual cathode reflex triode are given according to the simulations.展开更多
In laser wakefield acceleration,injecting an external electron beam at a certain energy is a promising approach for achieving a high-quality electron beam with low energy spread and low emittance.In this paper,the pro...In laser wakefield acceleration,injecting an external electron beam at a certain energy is a promising approach for achieving a high-quality electron beam with low energy spread and low emittance.In this paper,the process of laser wakefield acceleration with an external injection at 10 pC has been studied in simulations.A Bayesian optimization method is used to optimize the key laser and plasma parameters so that the electron beam is accelerated to the expected energy with a small emittance and energy spread growth.The effect of the rising edge of the plasma on the transverse properties of the electron beam is simulated and optimized in order to ensure that the external electron beam is injected into the plasma without significant emittance growth.Finally,a high-quality electron beam with an energy of 1.5 GeV,a normalized transverse emittance of 0.5 mm·mrad and a relative energy spread of 0.5%at 10 pC is obtained.展开更多
Neutral beam injection(NBI)has been proven as a reliable heating and current drive method for fusion plasma.For the high-energy NBI system(particle energy>150 ke V)of large-scale fusion devices,the negative ion sou...Neutral beam injection(NBI)has been proven as a reliable heating and current drive method for fusion plasma.For the high-energy NBI system(particle energy>150 ke V)of large-scale fusion devices,the negative ion source neutral beam injection(NNBI)system is inevitable,which can obtain an acceptable neutralization efficiency(>55%).But the NNBI system is very complex and challengeable.To explore and master the key NNBI technology for future fusion reactor in China,an NNBI test facility is under development in the framework of the Comprehensive Research Facility for Fusion Technology(CRAFT).The initial goal of CRAFT NNBI facility is to achieve a 2 MW hydrogen neutral beam at the energy of 200–400 ke V for lasting 100 s.In the first operation of the CRAFT NNBI facility,a negative ion source with dual RF drivers was developed and tested.By using the 50 keV accelerator,the long-pulse and highcurrent extractions of negative hydrogen ions have been achieved and the typical values were 55.4 keV,7.3 A(~123 A/m^(2)),105 s and 55.0 keV,14.7 A(~248 A/m^(2)),30 s,respectively.By using the 200 keV accelerator,the megawatt-class negative hydrogen beam has also been achieved(135.9 keV,8.9 A,8 s).The whole process of the gas neutralization of negative ion beam,electric removal of residual ions,and beam transport have been demonstrated experimentally.展开更多
An optical emission spectroscopy(OES)method with a non-invasive measurement capability,without inducing disturbance to the discharge,represents an effective method for material monitoring.However,when the OES method i...An optical emission spectroscopy(OES)method with a non-invasive measurement capability,without inducing disturbance to the discharge,represents an effective method for material monitoring.However,when the OES method is employed to monitor the trace erosion product within the ceramic channel of a Hall thruster,it becomes challenging to distinguish between signal and noise.In this study,we propose a model filtering method based on the signal characteristics of the Hall thruster plume spectrometer.This method integrates the slit imaging and spectral resolution features of the spectrometer.Employing this method,we extract the spectral signals of the erosion product and working gas from the Hall thruster under different operating conditions.The results indicate that our new method performs comparably to the traditional method without model filtering when extracting atom signals from strong xenon working gas.However,for trace amounts of the erosion product,our approach significantly enhances the signal-to-noise ratio(SNR),enabling the identification of extremely weak spectral signals even under low mass flow rate and low-voltage conditions.We obtain boron atom concentration of 3.91×10^(-3) kg/m^(3) at a mass flow rate of 4×10^(-7) kg/s and voltage of 200 V while monitoring a wider range of thruster operating conditions.The new method proposed in this study is suitable for monitoring other low-concentration elements,making it valuable for materials processing,environmental monitoring and space propulsion applications.展开更多
This paper presents the first comprehensive simulation study of p-11B fusion reactions in a spherical torus.We developed relevant program modules for fusion reactions based on energetic particle simulation frameworks ...This paper presents the first comprehensive simulation study of p-11B fusion reactions in a spherical torus.We developed relevant program modules for fusion reactions based on energetic particle simulation frameworks and analyzed the two main fusion channels:thermal and beam-thermal.Using EHL-2 design parameters with n_(boron)=007n_(ion)and a hydrogen beam at 200 keV and 1 MW,our simulation indicates that p-11B reactions produce approximately 1.5×10^(15)αparticles per second(~0.7 kW)from the thermal channel,and5.3×10^(14)(~0.25 kW)from the beam-thermal channel.We conducted parameter scans to establish a solid physics foundation for the high ion temperature conditions(T_(i)>26ke V)designed for EHL-2.This work also laid the groundwork for studying various operation modes to explore different reaction channels.The simulation results suggest that the conditions in EHL-2 could be sufficient for investigating p-11B thermonuclear reactions.In addition,we found that EHL-2 offered good confinement for energetic particles,allowing us to research the interactions between these ions and plasmas.This research enhances our understanding of burning plasma physics.展开更多
A new method for directly injecting plasma into the central cell of the Keda Mirror with AXisymmetricity(KMAX)device by using a compact toroid(CT)has been developed.This radial injection approach overcomes the limitat...A new method for directly injecting plasma into the central cell of the Keda Mirror with AXisymmetricity(KMAX)device by using a compact toroid(CT)has been developed.This radial injection approach overcomes the limitations of conventional plasma initiation methods,which typically rely on injecting plasma from one or both ends in a magnetic mirror configuration.The radial injection method aims to produce high-density plasma and facilitate studies of mirror-confined plasma.This paper presents its latest results and provides a detailed description of the injection system design.Our findings confirm the theoretical prediction that the injected plasma must achieve sufficient speed to penetrate the magnetic field and reach the chamber's center.Experimental observations show that,at medium voltage,the plasmoid may linger near the chamber edge,marking the first experimental identification of the conditions required for plasma penetration.展开更多
This research focuses on solving the fault detection and health monitoring of high-power thyristor converter.In terms of the critical role of thyristor converter in nuclear fusion system,a method based on long short-t...This research focuses on solving the fault detection and health monitoring of high-power thyristor converter.In terms of the critical role of thyristor converter in nuclear fusion system,a method based on long short-term memory(LSTM)neural network model is proposed to monitor the operational state of the converter and accurately detect faults as they occur.By sampling and processing a large number of thyristor converter operation data,the LSTM model is trained to identify and detect abnormal state,and the power supply health status is monitored.Compared with traditional methods,LSTM model shows higher accuracy and abnormal state detection ability.The experimental results show that this method can effectively improve the reliability and safety of the thyristor converter,and provide a strong guarantee for the stable operation of the nuclear fusion reactor.展开更多
ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation （red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk） was used as mat...ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation （red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk） was used as material; HPLC analysis of β-carotene content was conducted. ResultThe β-carotene concentration in the flesh of wild and mutant types was 60.9 and 4.6 μg/g fresh weight, respectively. According to the conserved regions of genes from rose family genome, carotenogenic gene fragments in wild and mutant types were obtained. No nucleotide variation of the carotenogenic gene fragments was observed between wild and mutant genome. Real-time quantitative polymerase chain reaction （Q-PCR） was compared and one carotenogenic gene, β-ring hydroxylase （HYB） were considerably suppressed in mature mutant loquat fruits compared with that in wild. The other six carotenogenic genes were also expressed but the expression patterns appeared to be not correlated with the amount of β-carotene concentration in wild loquat flesh. ConclusionThe mutant whitish loquat lacks the ability to synthesize β-carotene because of the transcriptional down-regulation of carotenogenic gene HYB.展开更多
基金Supported by NSFC(Grant Nos.12171402,12101600)the Fundamental Research Funds for the Central Universities(Grant Nos.20720190062,2021QN1037)。
文摘In this article we show that any embedded graph has a checkerboard colourable twual,which is equivalent to having a bipartite twual.We also obtain that any Eulerian embedded graph has a checkerboard colourable partial Petrial,answering questions posed by Ellis-Monaghan and Moffatt[Trans.Amer.Math.Soc.,364,1529–1569(2012)].
文摘AIM:To compare the Ishihara test errors scores of colour vision deficiency(CVD)subjects when wearing four different types of red-tinted contact lenses(RCL)that differ in their transmittance as determined using a spectrophotometer.METHODS:Six congenital CVD subjects volunteered to participate in this study.Ishihara plates were used to determine the colour vision errors made,whereas Farnsworth-Munsell 100 Hue test was conducted to determine the total error scores(TES)and type of CVD.Four types of RCL(Types A,B,C and D)were inserted in the non-dominant eye and tested in a randomised manner by a masked operator.Errors scores in Ishihara test were determined at baseline without any contact lens and after wearing the four different RCL.The subjects were then divided into two groups based on the mean TES.RESULTS:Repeated measures ANOVA with Greenhouse-Geisser corrections showed that there was a highly significant effect of RCL type on Ishihara error score[F(2.056,10.282)=30.214,P<0.001].Error scores with RCL Type B were significantly lower than errors made when no lens was worn,and with RCL Type C and Type D(all P<0.001).Error scores with RCL Type B were also lower than those made with RCL Type A,however,they were not significantly different.For subjects with TES values less than 180,RCL type B showed the largest improvement in Ishihara error score(50%)compared to the other three RCLs.RCL type A showed the best performance in TES value of more than 180,with an improvement of 80%in Ishihara score.RCL Type A has the lowest transmittance at the confusion wavelength(450-568 nm),followed by RCL Types B,D and C.CONCLUSION:This study shows that RCL can improve Ishihara error scores.RCL with lower transmission at 450-568 nm and 90%transmittance beyond 637 nm are the most effective.Lenses which could block more light between 550-580 nm are more effective for colour defectives with more severe colour defects.
基金supported by a Singapore National Research Foundation(NRF)Investigatorship(NRF-NRFI07-2021-0008)。
文摘Quantitative analysis of colouration is an essential tool for subspecies delimitation but has always posed a challenge in avian taxonomy.In this study on the Chestnut-winged Babbler(Cyanoderma erythropterum)species complex from tropical Southeast Asia,we made use of colour measurements taken with digital cameras and applied two methodologies—(1)the 75%subspecies rule on quantitative colourimetric variables,and(2)the CIEDE2000 colour distance method to generate phylograms,which has probably never been applied in taxonomy before.Given its large number of described subspecies,many of which have been synonymised in modern taxonomies,the species complex serves as an appropriate model to test subspecies validity.Our data indicate that one synonymised subspecies(C.e.apega),from the islands of Bangka and Belitung,requires re-instalment and recognition,whereas one widely recognised subspecies(C.e.fulviventre),from the Banyak Islands,should be synonymised.Our approach also allowed us to redraw geographic subspecies boundaries.Our work indicates that current subspecies taxonomies of many poorly known tropical species may remain error-ridden and highlights the importance and viability of large-scale taxonomic revisions targeting avian subspecies globally while incorporating quantitative colourimetric approaches.
文摘This work presents a grounding protection system of the central solenoid model coil(CSMC)of the Comprehensive Research Facility for Fusion Technology(CRAFT).The scheme of neutral point voltage detections has been adopted in grounding protection system.Compared with the usual current acquisition,the measurement data is accurate,there is no redundant loop,and the economic benefit is high.In this study,the single-end and double-end grounding fault protections of superconducting magnet coil are analyzed,and the fault voltage and current under different fault conditions are calculated.The simulation model of CSMC magnet grounding fault is established,and the simulation results of the model are basically consistent with the theoretical calculation.Finally,a small capacity experiment platform is used to verify the function of the grounding protection system.The experimental results show that by comparing the neutral fault sampling voltage with the theoretical grounding protection threshold,the grounding protection system can effectively detect different types of grounding faults and transmit signals to the control system to protect the coils of superconducting magnets.
基金supported by the Comprehensive Research Facility for Fusion Technology Program of China(No.2018000052-73-01-001228)National Natural Science Foundation of China(No.11975263)Postgraduate Research and Practice Innovation Program of NUAA(No.xcxjh20231501)。
文摘The negative ion based neutral beam injector(NNBI)with a beam energy of 400 keV is one of the subsystems at the Comprehensive Research fAcility for Fusion Technology(CRAFT)in China.The distributed capacitance of the high-voltage components is an important basis for the design of surge suppression devices at CRAFT NNBI.This study conducted calculations of distributed capacitance for the key components,including the high-voltage deck,transmission line and isolation transformer in the power supply system using the finite element method.The relationship between the high-voltage deck(HVD)distributed capacitance and the distance from the wall is discussed.The differences in distributed capacitance and energy storage between noncoaxial and coaxial transmission lines are also debated.Finally,the capacitance between the primary and secondary windings of the-400 kV isolation transformer,as well as between the secondary winding and the oil tank casing,was calculated.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2022YFE03100004,2017YFE0301700 and 2017 YFE0301701)National Natural Science Foundation of China(Nos.12375226,11875255,11635008,11375188 and 11975231)。
文摘The electromagnetic turbulence in reversed field pinch(RFP)plasmas exhibits three-dimensional characteristics.Suppression of this turbulence is crucial for enhancing plasma confinement,necessitating control over the electric field or the current profile.To this end,two sets of electrodes have been designed and installed on the Keda Torus eXperiment(KTX)RFP device to manipulate the edge electric field and the edge parallel current profile.Subsequently,the edge radial electric field and edge parallel current profile control experiments are conducted.In the edge radial electric field control experiments,the edge radial electric field is altered under bias,accompanied with an increase in the electron density and plasma duration.However,under bias,both electrostatic and magnetic fluctuations are enhanced.In the edge parallel current profile control experiments,the results indicate that bias modifies the edge parallel current profile locally,leading to a localized increase in the field reversal depth and electron density.Additionally,a reduction in magnetic fluctuations is observed within the reversed field enhanced region under bias,suggesting that the bias suppresses magnetic perturbations.
基金the financial support of National Natural Science Foundation of China(Nos.52207175 and 52407178)。
文摘When discharge faults occur in dry air switchgear,the air decomposes to produce diverse gases,with NO_(2) reaching the highest levels.Detecting the NO_(2) level can reflect the operation status of the equipment.This paper proposes to combine ZnO cluster with MoS_(2) to improve the gassensitive properties of the monolayer.Based on the Density Functional Theory(DFT),the effect of(ZnO)n size on the behavior of MoS_(2 )is considered.Key parameters such as adsorption energy and band gap of(ZnO)n-MoS_(2)/NO_(2) system were calculated.The ZnO-MoS_(2) heterojunction was successfully synthesized by a hydrothermal method.The gas sensor exhibits a remarkable response and a fast response-recovery time to 100 ppm NO_(2).In addition,it demonstrates excellent selectivity,long-term stability and a low detection limit.This work confirms the potential of the ZnO-MoS_(2) composite structure as a highly effective gas sensor for NO_(2) detection,which provides valuable theoretical and experimental insights for fault detection in dry air switchgear.
基金partly supported by SWIP project(No.SWIP-JYHT-12423).
文摘The EHL-2 spherical torus at ENN is the next-generation experimental platform under conceptual design,aiming at realizing proton-boron(p-^(11)B)thermonuclear fusion,which is an attractive pathway towards neutron-free fusion.To achieve high-performance steady-state plasma,it is extremely necessary to study the turbulence transport characteristics with high boron content in the plasma core.This study investigates the transport properties in the core internal transport barrier(ITB)region of p-^(11)B plasma utilizing the gyrokinetic code GENE in view of the high ion temperature scenario of EHL-2,specifically focusing on the impact of boron fractions and plasmaβon the microinstabilities and corresponding transport features.Numerical findings indicate that the inclusion of boron species effectively suppresses the trapped electron modes(TEMs)as well as promoting a transition from electromagnetic to electrostatic turbulence with increased boron fraction,which is a result of the suppression of microinstabilities by effective charge and mass.Moreover,it has been identified that the external E×B rotational shear has a notable inhibitory influence on transport,which can reduce the transport level by two to three orders of magnitude,especially at medium boron content.The suppressive effect of E×B on turbulence is weakened once the kinetic ballooning mode(KBM)is excited and the transport shows a rapid increase withβtogether with a reduction in zonal flow amplitude,which is consistent with previous findings.Therefore,it is strongly suggested that exploring advanced strategies for mitigating turbulent transport at highβregimes is necessary for the active control of plasma behavior regarding p-^(11)B plasma-based fusion devices such as EHL-2.
基金supported by National Natural Science Foundation of China(Nos.52077026,51977023,52177126 and 12475253)the Fundamental Research Funds for the Central Universities(No.DUT23YG227)the Dalian Life&Health Guiding Project(No.2023ZXYG34)。
文摘In this study,we explored a one-step direct synthesis of NH3 under mild experimental conditions utilizing pulse-modulated microwave plasma technology at atmospheric pressure.At a substantial gas flow rate,a microwave plasma jet was formed and the microwave-assisted ammonia synthesis can be realized.Impacts of various parameters including the gas flow rate,gas component,microwave absorbed power,pulse modulation frequency,and pulse duty cycle on ammonia synthesis were systematically investigated.To indicate the reaction path of ammonia synthesis,the distributions of both the gas temperature and active species were also studied using optical emission spectra technology.It is found that a considerable amount of ammonia was directly synthesized without involvement of any catalysts,the highest ammonia production rate and energy efficiency(EE),up to 2.93μmol·min^(-1) and 6.64×10^(-2)g·(k W·h)^(-1),respectively,were achieved under low microwave power of 84.42 W.The duty cycle has obvious influences on the synthesis efficiency,compared to a duty cycle of 80%,the ammonia synthesis rate,EE and nitrogen conversion decreased by about 22%at a duty cycle of 100%.This finding underscores the significance of incorporating pulse modulation in the microwave discharge process for ammonia synthesis.Furthermore,it was found that vibrational excitation of microwave plasma has a significant driving effect on ammonia synthesis.
基金supported by the Independent Innovation Science Fund of National University of Defense Technology(No.24-ZZCX-BC-05)National Natural Science Foundation of China(Nos.92271110 and 12202488)+2 种基金the Major National Science and Technology Project(No.J2019-Ⅲ0010-0054)the National Postdoctoral Researcher Program of China(No.GZB20230985)the Natural Science Program of National University of Defense Technology(No.ZK22-30)。
文摘The phenomenon of shock/shock interaction(SSI)is widely observed in high-speed flow,and the double wedge SSI represents one of the typical problems encountered.The control effect of single-pulse plasma synthetic jet(PSJ)on double wedge type-Ⅵand type-ⅤSSI was investigated experimentally and numerically,and the influence of discharge energy was also explored.The findings indicate that the interaction between PSJ and the high-speed freestream results in the formation of a plasma layer and a jet shock,which collectively governs the control of SSI.The control mechanism of single-pulse PSJ on SSI lies in its capacity to attenuate both shock and SSI.For type-ⅥSSI,the original second-wedge oblique shock is eliminated under the control of PSJ,resulting in a new type-ⅥSSI formed by the jet shock and the first-wedge oblique shock.For type-ⅤSSI,the presence of PSJ effectively mitigates the intensity of Mach stem,supersonic jet,and reflected shocks,thereby facilitating its transition into type-ⅥSSI.The numerical results indicate that the peak pressure can be reduced by approximately 32.26%at maximum.Furthermore,the development of PSJ also extends in the Z direction.The pressure decreases in the area affected by both PSJ and jet shock due to the attenuation of the SSI zone.With increasing discharge energy,the control effect of PSJ on SSI is gradually enhanced.
文摘ENN is planning the next generation experimental device EHL-2 with the goal to verify the thermal reaction rates of p-^(11)B fusion,establish spherical torus/tokamak experimental scaling laws at 10’s keV ion temperature,and provide a design basis for subsequent experiments to test and realize the p-^(11)B fusion burning plasma.Based on 0-dimensional(0-D)system design and 1.5-dimensional transport modelling analyses,the main target parameters of EHL-2 have been basically determined,including the plasma major radius,R0,of 1.05 m,the aspect ratio,A,of 1.85,the maximum central toroidal magnetic field strength,B0,of 3 T,and the plasma toroidal current,Ip,of 3 MA.The main heating system will be the neutral beam injection at a total power of 17 MW.In addition,6 MW of electron cyclotron resonance heating will serve as the main means of local current drive and MHD instabilities control.The physics design of EHL-2 is focused on addressing three main operating scenarios,i.e.,(1)high ion temperature scenario,(2)high-performance steady-state scenario and(3)high triple product scenario.Each scenario will integrate solutions to different important issues,including equilibrium configuration,heating and current drive,confinement and transport,MHD instability,p-^(11)B fusion reaction,plasma-wall interactions,etc.Beyond that,there are several unique and significant challenges to address,including●establish a plasma with extremely high core ion temperature(T_(i,0)>30 keV),and ensure a large ion-to-electron tempera-ture ratio(T_(i,0)/Te,0>2),and a boron concentration of 10%‒15%at the plasma core;●realize the start-up by non-inductive current drive and the rise of MA-level plasma toroidal current.This is because the volt-seconds that the central solenoid of the ST can provide are very limited;●achieve divertor heat and particle fluxes control including complete detachment under high P/R(>20 MW/m)at rela-tively low electron densities.This overview will introduce the advanced progress in the physics design of EHL-2.
基金supported by National Natural Science Foundation of China(Nos.12027811 and 12275222)。
文摘The cylindrical virtual cathode reflex triode is a new type of pulsed hard X-ray load,which has the advantages of simple structure,high radiation conversion efficiency,and simplicity in seriesparallel operation.This paper presents a method to reduce the impedance of the triode using a multiring cathode.The average electric field on the ring-cathode emission surface is enhanced due to edge effect,and the beam intensity is greatly increased in proportion to the square of the electric field strength.Multi-ring cathode is used to enlarge the emission area.Therefore,the reflex triode can work at lower impedance and generate a stronger beam under the same anode-cathode gap.In addition,the electric field enhancement of the cathode reduces the cathode emission stabilization time and enhances the operation stability of the triode.The effects of parameters such as ring width and ring gap on the triode impedance are simulated and studied.The cathode emission stabilization time and the X-ray conversion efficiency are compared.The design basis of cathode structure parameters and the impedance control method of the cylindrical virtual cathode reflex triode are given according to the simulations.
基金supported by Science and Technology Major Project of Hubei Province in China(No.2021AFB001)。
文摘In laser wakefield acceleration,injecting an external electron beam at a certain energy is a promising approach for achieving a high-quality electron beam with low energy spread and low emittance.In this paper,the process of laser wakefield acceleration with an external injection at 10 pC has been studied in simulations.A Bayesian optimization method is used to optimize the key laser and plasma parameters so that the electron beam is accelerated to the expected energy with a small emittance and energy spread growth.The effect of the rising edge of the plasma on the transverse properties of the electron beam is simulated and optimized in order to ensure that the external electron beam is injected into the plasma without significant emittance growth.Finally,a high-quality electron beam with an energy of 1.5 GeV,a normalized transverse emittance of 0.5 mm·mrad and a relative energy spread of 0.5%at 10 pC is obtained.
基金supported by the Comprehensive Research Facility for Fusion Technology Program of China(No.2018-000052-73-01-001228)。
文摘Neutral beam injection(NBI)has been proven as a reliable heating and current drive method for fusion plasma.For the high-energy NBI system(particle energy>150 ke V)of large-scale fusion devices,the negative ion source neutral beam injection(NNBI)system is inevitable,which can obtain an acceptable neutralization efficiency(>55%).But the NNBI system is very complex and challengeable.To explore and master the key NNBI technology for future fusion reactor in China,an NNBI test facility is under development in the framework of the Comprehensive Research Facility for Fusion Technology(CRAFT).The initial goal of CRAFT NNBI facility is to achieve a 2 MW hydrogen neutral beam at the energy of 200–400 ke V for lasting 100 s.In the first operation of the CRAFT NNBI facility,a negative ion source with dual RF drivers was developed and tested.By using the 50 keV accelerator,the long-pulse and highcurrent extractions of negative hydrogen ions have been achieved and the typical values were 55.4 keV,7.3 A(~123 A/m^(2)),105 s and 55.0 keV,14.7 A(~248 A/m^(2)),30 s,respectively.By using the 200 keV accelerator,the megawatt-class negative hydrogen beam has also been achieved(135.9 keV,8.9 A,8 s).The whole process of the gas neutralization of negative ion beam,electric removal of residual ions,and beam transport have been demonstrated experimentally.
基金financially supported by National Natural Science Foundation of China(No.U22B2094)。
文摘An optical emission spectroscopy(OES)method with a non-invasive measurement capability,without inducing disturbance to the discharge,represents an effective method for material monitoring.However,when the OES method is employed to monitor the trace erosion product within the ceramic channel of a Hall thruster,it becomes challenging to distinguish between signal and noise.In this study,we propose a model filtering method based on the signal characteristics of the Hall thruster plume spectrometer.This method integrates the slit imaging and spectral resolution features of the spectrometer.Employing this method,we extract the spectral signals of the erosion product and working gas from the Hall thruster under different operating conditions.The results indicate that our new method performs comparably to the traditional method without model filtering when extracting atom signals from strong xenon working gas.However,for trace amounts of the erosion product,our approach significantly enhances the signal-to-noise ratio(SNR),enabling the identification of extremely weak spectral signals even under low mass flow rate and low-voltage conditions.We obtain boron atom concentration of 3.91×10^(-3) kg/m^(3) at a mass flow rate of 4×10^(-7) kg/s and voltage of 200 V while monitoring a wider range of thruster operating conditions.The new method proposed in this study is suitable for monitoring other low-concentration elements,making it valuable for materials processing,environmental monitoring and space propulsion applications.
基金supported by ENN Group and ENN Energy Research Institute.
文摘This paper presents the first comprehensive simulation study of p-11B fusion reactions in a spherical torus.We developed relevant program modules for fusion reactions based on energetic particle simulation frameworks and analyzed the two main fusion channels:thermal and beam-thermal.Using EHL-2 design parameters with n_(boron)=007n_(ion)and a hydrogen beam at 200 keV and 1 MW,our simulation indicates that p-11B reactions produce approximately 1.5×10^(15)αparticles per second(~0.7 kW)from the thermal channel,and5.3×10^(14)(~0.25 kW)from the beam-thermal channel.We conducted parameter scans to establish a solid physics foundation for the high ion temperature conditions(T_(i)>26ke V)designed for EHL-2.This work also laid the groundwork for studying various operation modes to explore different reaction channels.The simulation results suggest that the conditions in EHL-2 could be sufficient for investigating p-11B thermonuclear reactions.In addition,we found that EHL-2 offered good confinement for energetic particles,allowing us to research the interactions between these ions and plasmas.This research enhances our understanding of burning plasma physics.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0790303)National Natural Science Foundation of China(No.12175226)。
文摘A new method for directly injecting plasma into the central cell of the Keda Mirror with AXisymmetricity(KMAX)device by using a compact toroid(CT)has been developed.This radial injection approach overcomes the limitations of conventional plasma initiation methods,which typically rely on injecting plasma from one or both ends in a magnetic mirror configuration.The radial injection method aims to produce high-density plasma and facilitate studies of mirror-confined plasma.This paper presents its latest results and provides a detailed description of the injection system design.Our findings confirm the theoretical prediction that the injected plasma must achieve sufficient speed to penetrate the magnetic field and reach the chamber's center.Experimental observations show that,at medium voltage,the plasmoid may linger near the chamber edge,marking the first experimental identification of the conditions required for plasma penetration.
基金supported by the Open Fund of Magnetic Confinement Fusion Laboratory of Anhui Province(No.2024AMF04003)the Natural Science Foundation of Anhui Province(No.228085ME142)Comprehensive Research Facility for Fusion Technology(No.20180000527301001228)。
文摘This research focuses on solving the fault detection and health monitoring of high-power thyristor converter.In terms of the critical role of thyristor converter in nuclear fusion system,a method based on long short-term memory(LSTM)neural network model is proposed to monitor the operational state of the converter and accurately detect faults as they occur.By sampling and processing a large number of thyristor converter operation data,the LSTM model is trained to identify and detect abnormal state,and the power supply health status is monitored.Compared with traditional methods,LSTM model shows higher accuracy and abnormal state detection ability.The experimental results show that this method can effectively improve the reliability and safety of the thyristor converter,and provide a strong guarantee for the stable operation of the nuclear fusion reactor.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest of China(201003073)Key Laboratory Program of Agriculture Ministry of China(2013JCYJ-004)+1 种基金Applied Basic Research Program of Chengdu City Science and Technology Bureau(11DXYB039NC)Youth Foundation of Sichuan Province(2011QNJJ-010)~~
文摘ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation （red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk） was used as material; HPLC analysis of β-carotene content was conducted. ResultThe β-carotene concentration in the flesh of wild and mutant types was 60.9 and 4.6 μg/g fresh weight, respectively. According to the conserved regions of genes from rose family genome, carotenogenic gene fragments in wild and mutant types were obtained. No nucleotide variation of the carotenogenic gene fragments was observed between wild and mutant genome. Real-time quantitative polymerase chain reaction （Q-PCR） was compared and one carotenogenic gene, β-ring hydroxylase （HYB） were considerably suppressed in mature mutant loquat fruits compared with that in wild. The other six carotenogenic genes were also expressed but the expression patterns appeared to be not correlated with the amount of β-carotene concentration in wild loquat flesh. ConclusionThe mutant whitish loquat lacks the ability to synthesize β-carotene because of the transcriptional down-regulation of carotenogenic gene HYB.
