In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar ...In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.展开更多
Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major ...Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants, especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.展开更多
An AlSiY coating and two MCrAlY+AlSiY composite coatings with different thickness of MCrAlY interlayer were prepared by arc ion plating(AIP)and vacuum annealing.The isothermal oxidation behavior of coatings at 1100℃ ...An AlSiY coating and two MCrAlY+AlSiY composite coatings with different thickness of MCrAlY interlayer were prepared by arc ion plating(AIP)and vacuum annealing.The isothermal oxidation behavior of coatings at 1100℃ for 300 h was also investigated to characterize the microstructure evolution of coatings during annealing.The composite coatings exhibited a better high-temperature oxidation resistance at 1100℃ .The reason is that the addition of MCrAlY layer can greatly contribute to prevent the diffusion of refractory elements to the outer layer.The inhibition of Al inward diffusion can be much stronger,as the Si content increases in the outer layer during annealing.展开更多
Cyclic oxidation behavior of Ni Cr Al YSi+Ni Al/c BN abrasive coating at 900°C and the mechanical properties of the coating-substrate system were investigated.Results indicated that elemental interdiffusion occur...Cyclic oxidation behavior of Ni Cr Al YSi+Ni Al/c BN abrasive coating at 900°C and the mechanical properties of the coating-substrate system were investigated.Results indicated that elemental interdiffusion occurred between the coating and substrate,which caused the formation of interdiffusion zone(IDZ)and secondary reaction zone(SRZ)during aluminization,while their compositions and structures changed with oxidation.Al N interfacial layer formed at c BN/metallic matrix interface during aluminization,while it transformed into multilayer oxides during oxidation.Due to the microstructural evolution of these interfaces,the fracture behavior and bending toughness of the system changed greatly during three-point bending tests.Besides,the damage mechanisms were discussed.展开更多
The hot corrosion behavior of the NiAl coating and the 5Hf-NiAl coating induced by mixed salt at 900℃was investigated.Comparing with the NiAl coating,the 5Hf-NiAl coating exhibited superior hot corrosion resistance b...The hot corrosion behavior of the NiAl coating and the 5Hf-NiAl coating induced by mixed salt at 900℃was investigated.Comparing with the NiAl coating,the 5Hf-NiAl coating exhibited superior hot corrosion resistance because the addition of Hf promoted the formation of protective oxide scale and reduced the growth rate of oxide scale.Therefore,internal sulfides were not present in the 5Hf-NiAl coating after hot corrosion for 140 h.Cr exhibited different distribution in the two coatings since the addition of Hf changed the hot corrosion process of the coating.Hf and Ti in the 5Hf-NiAl coating trapped and captured sulfur,preventing the penetration of sulfur into the coating.The hot corrosion mechanism of the two coating and the effects of Hf on this process were discussed in this work.展开更多
The grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18 Cr-17 Mn-2 Mo-0.85 N high-n...The grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18 Cr-17 Mn-2 Mo-0.85 N high-nitrogen nickel-free austenitic stainless steel were systematically explored.The results show that stacking faults and planar slip bands appearing at the right amount of deformation(lower than 10%) are beneficial cold-rolled microstructures to the GBCD optimization.The proportion of special boundaries gradually increases in the subsequent stages of recrystallization and grain growth,accompanying with the growth of twin-related domain in the experimental steel.In this way,the fraction of low ∑ coincidence site lattice(CSL) boundaries can reach as high as 82.85% for the specimen cold-rolled by 5% and then annealed at 1423 K for 72 h.After GBCD optimization,low ∑ CSL boundaries and the special triple junctions(J2,J3) of high proportion can greatly hinder the nitride precipitation along grain boundaries and enhance the capability for intergranular crack arrest,thus improving the IGSCC resistance of the experimental steel.展开更多
The mid-T_(C) superconductor Ba1-XKXBiO3(BKBO)exhibits different superconducting mechanisms depending on x,in the range∼0.35–0.65.The optimal doping for the highest T_(C) is reported to be around x=0.4.To understand...The mid-T_(C) superconductor Ba1-XKXBiO3(BKBO)exhibits different superconducting mechanisms depending on x,in the range∼0.35–0.65.The optimal doping for the highest T_(C) is reported to be around x=0.4.To understand more about the dependence of the superconducting mechanism on x,high quality and reproducible epitaxial films with controlled x are needed.This has been challenging owing to the volatility of K and(to a lesser extent)Bi.In this work,we use pulsed laser deposition(PLD)with several novel process steps to achieve high-quality films in a reproducible way.These include a modified method for target preparation,a low NO_(2) growth pressure,and precise positioning of substrates in the PLD plume.Optimum T_(C) films(32 K onset)were grown from an x=0.4 target,i.e.with no excess K,as is normally used.Stable,higher K content films(made from an x=0.45 target),were also grown.These x=0.45 films had a lower T_(C) (22.5 K onset),as expected for(K)overdoped films,with very high upper critical field,H_(C2) (0 K),and irreversibility field,Hirr(0 K),values,from linear extrapolation,of∼31.7 T and∼28.8 T,respectively.The growth methodology demonstrated in this work is highly beneficial for fundamental mechanistic studies of this complex superconductor on which there is renewed interest,and where controlled compositions and crystalline quality are currently limited.展开更多
Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the tr...Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with extens-ive systematic studies of the dihadron correlations as a function ofФ_(s),trigger and associated particle pT,and the pseudo-rapidity range△_(η),should provide stringent inputs to help understand the underlying physics mechanisms of jet-medium interactions in high energy nuclear collisions.展开更多
Selection of sugar beet(Beta vulgaris L.)cultivars that are resistant to Cercospora Leaf Spot(CLS)disease is critical to increase yield.Such selection requires an automatic,fast,and objective method to assess CLS seve...Selection of sugar beet(Beta vulgaris L.)cultivars that are resistant to Cercospora Leaf Spot(CLS)disease is critical to increase yield.Such selection requires an automatic,fast,and objective method to assess CLS severity on thousands of cultivars in the field.For this purpose,we compare the use of submillimeter scale RGB imagery acquired from an Unmanned Ground Vehicle(UGV)under active illumination and centimeter scale multispectral imagery acquired from an Unmanned Aerial Vehicle(UAV)under passive illumination.Several variables are extracted from the images(spot density and spot size for UGV,green fraction for UGV and UAV)and related to visual scores assessed by an expert.Results show that spot density and green fraction are critical variables to assess low and high CLS severities,respectively,which emphasizes the importance of having submillimeter images to early detect CLS in field conditions.Genotype sensitivity to CLS can then be accurately retrieved based on time integrals of UGV-and UAV-derived scores.While UGV shows the best estimation performance,UAV can show accurate estimates of cultivar sensitivity if the data are properly acquired.Advantages and limitations of UGV,UAV,and visual scoring methods are finally discussed in the perspective of high-throughput phenotyping.展开更多
High transverse momentum(pT)particle production is suppressed owing to the parton(jet)energy loss in the hot dense medium created in relativistic heavy-ion collisions.Redistribution of energy at low-to-modest pT has b...High transverse momentum(pT)particle production is suppressed owing to the parton(jet)energy loss in the hot dense medium created in relativistic heavy-ion collisions.Redistribution of energy at low-to-modest pT has been difficult to measure,owing to large anisotropic backgrounds.We report a data-driven method for background evaluation and subtraction,exploiting the away-side pseudorapidity gaps,to measure the jetlike correlation shape in Au+Au collisions at √sNN=200 GeV in the STAR experiment.The correlation shapes,for trigger particles pT>3GeV/c and various associated particle pT ranges within 0.5<pT<10GeV/c,are consistent with Gaussians,and their widths increase with centrality.The results indicate jet broadening in the medium created in central heavy-ion collisions.展开更多
The initial-stage oxidation behaviours of unmodified,Pt and Pt+Hf modified NiAl coating are systematically investigated by employing the photo-stimulated luminescence spectroscopy(PSLS)and transmission electron micros...The initial-stage oxidation behaviours of unmodified,Pt and Pt+Hf modified NiAl coating are systematically investigated by employing the photo-stimulated luminescence spectroscopy(PSLS)and transmission electron microscopy(TEM)technique.Both Pt and Hf additions can retard the θ-toα-Al_(2)O_(3)phase transformation.The oxidation rates of the modified NiAl coatings are initially higher than that of the unmodified NiAl coating due to the longer presence of θ-Al_(2)O_(3).However,they decrease drastically when the oxide in the scale turns to be α-Al_(2)O_(3)dominantly.The delayed phase transformation in the modified coatings results in lower residual stress within the oxide scale.展开更多
Recent measurements of event-by-event elliptic flow in Au+Au collisions at S_(NN)^(1/2)=200GeV exhibit large relative fluctuations of about 40%—50%.The data are well described by fluctuations in the shape of the init...Recent measurements of event-by-event elliptic flow in Au+Au collisions at S_(NN)^(1/2)=200GeV exhibit large relative fluctuations of about 40%—50%.The data are well described by fluctuations in the shape of the initial collision region,as estimated event-by-event with the participant eccentricity using Glauber Monte Carlo.These results,combined with the demonstrated participant eccentricity scaling of the elliptic flow across nuclear species,constitute evidence of transverse granularity in the initial matter production in these collisions.展开更多
文摘In 2018,the STAR collaboration collected data from^(96)_(44)Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr at√^(S)NN=200 Ge V to search for the presence of the chiral magnetic effect in collisions of nuclei.The isobar collision species alternated frequently between 9644 Ru+^(96)_(44)Ru and^(96)_(40)Zr+^(96)_(40)Zr.In order to conduct blind analyses of studies related to the chiral magnetic effect in these isobar data,STAR developed a three-step blind analysis procedure.Analysts are initially provided a"reference sample"of data,comprised of a mix of events from the two species,the order of which respects time-dependent changes in run conditions.After tuning analysis codes and performing time-dependent quality assurance on the reference sample,analysts are provided a species-blind sample suitable for calculating efficiencies and corrections for individual≈30-min data-taking runs.For this sample,species-specific information is disguised,but individual output files contain data from a single isobar species.Only run-by-run corrections and code alteration subsequent to these corrections are allowed at this stage.Following these modifications,the"frozen"code is passed over the fully un-blind data,completing the blind analysis.As a check of the feasibility of the blind analysis procedure,analysts completed a"mock data challenge,"analyzing data from Au+Au collisions at√^(S)NN=27 Ge V,collected in 2018.The Au+Au data were prepared in the same manner intended for the isobar blind data.The details of the blind analysis procedure and results from the mock data challenge are presented.
基金supported by the National Natural Science Foundation of China (Grant 11502138)the National Key Research and Development Program (Grant 2016YFC0401500)the National Water Pollution Control and Treatment Science and Technology Major Project (Grant 2012ZX07506-002b)
文摘Vertical distribution processes of sediment contaminants in water were studied by flume experiments. Experimental results show that settling velocity of sediment particles and turbulence characteristics are the major hydrodynamic factors impacting distribution of pollutants, especially near the bottom where particle diameter is similar in size to vortex structure. Sediment distribution was uniform along the distance, while contaminant distribution slightly lagged behind the sediment. The smaller the initial sediment concentration was, the more time it took to achieve a uniform concentration distribution for suspended sediment. A contaminants transportation equation was established depending on mass conservation equations. Two mathematical estimation models of pollutant distribution in the overlying water considering adsorption and desorption were devised based on vertical distribution of suspended sediment: equilibrium partition model and dynamic micro-diffusion model. The ratio of time scale between the sediment movement and sorption can be used as the index of the models. When this ratio was large, the equilibrium assumption was reasonable, but when it was small, it might require dynamic micro-diffusion model.
基金supported by the Tianjin Major Science and Technology Project of Military-Civil Integration(No.18ZXJMTG00050)National Science and Technology Major Project under Grant(No.2017-VI-0002-0072)the National Natural Science Foundation of China(No.52001177)。
文摘An AlSiY coating and two MCrAlY+AlSiY composite coatings with different thickness of MCrAlY interlayer were prepared by arc ion plating(AIP)and vacuum annealing.The isothermal oxidation behavior of coatings at 1100℃ for 300 h was also investigated to characterize the microstructure evolution of coatings during annealing.The composite coatings exhibited a better high-temperature oxidation resistance at 1100℃ .The reason is that the addition of MCrAlY layer can greatly contribute to prevent the diffusion of refractory elements to the outer layer.The inhibition of Al inward diffusion can be much stronger,as the Si content increases in the outer layer during annealing.
基金supported by National Science and Technology Major Project(2017-VII-0012-0108)。
文摘Cyclic oxidation behavior of Ni Cr Al YSi+Ni Al/c BN abrasive coating at 900°C and the mechanical properties of the coating-substrate system were investigated.Results indicated that elemental interdiffusion occurred between the coating and substrate,which caused the formation of interdiffusion zone(IDZ)and secondary reaction zone(SRZ)during aluminization,while their compositions and structures changed with oxidation.Al N interfacial layer formed at c BN/metallic matrix interface during aluminization,while it transformed into multilayer oxides during oxidation.Due to the microstructural evolution of these interfaces,the fracture behavior and bending toughness of the system changed greatly during three-point bending tests.Besides,the damage mechanisms were discussed.
基金This work was supported by the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDRW-CN-2021-2-2)the Science Center for Gas Turbine Project(P2021-A-IV-002-003)+2 种基金the IMR Innovation Fund(2022-PY17)the Basic Research Project of Science,the Education and Industry Integration Pilot Project for Qilu University of Technology(Shandong Academy of Sciences)(2022PY063)the National Natural Science Foundation of China(No.5227011470).
文摘The hot corrosion behavior of the NiAl coating and the 5Hf-NiAl coating induced by mixed salt at 900℃was investigated.Comparing with the NiAl coating,the 5Hf-NiAl coating exhibited superior hot corrosion resistance because the addition of Hf promoted the formation of protective oxide scale and reduced the growth rate of oxide scale.Therefore,internal sulfides were not present in the 5Hf-NiAl coating after hot corrosion for 140 h.Cr exhibited different distribution in the two coatings since the addition of Hf changed the hot corrosion process of the coating.Hf and Ti in the 5Hf-NiAl coating trapped and captured sulfur,preventing the penetration of sulfur into the coating.The hot corrosion mechanism of the two coating and the effects of Hf on this process were discussed in this work.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51871048 and 52171108)the Fundamental Research Funds for the Central Universities(Grant Nos.N2002014 and N2202011)。
文摘The grain boundary character distribution(GBCD) optimization and its effect on the intergranular stress corrosion cracking(IGSCC) resistance in a cold-rolled and subsequently annealed Fe-18 Cr-17 Mn-2 Mo-0.85 N high-nitrogen nickel-free austenitic stainless steel were systematically explored.The results show that stacking faults and planar slip bands appearing at the right amount of deformation(lower than 10%) are beneficial cold-rolled microstructures to the GBCD optimization.The proportion of special boundaries gradually increases in the subsequent stages of recrystallization and grain growth,accompanying with the growth of twin-related domain in the experimental steel.In this way,the fraction of low ∑ coincidence site lattice(CSL) boundaries can reach as high as 82.85% for the specimen cold-rolled by 5% and then annealed at 1423 K for 72 h.After GBCD optimization,low ∑ CSL boundaries and the special triple junctions(J2,J3) of high proportion can greatly hinder the nitride precipitation along grain boundaries and enhance the capability for intergranular crack arrest,thus improving the IGSCC resistance of the experimental steel.
基金All the authors thank the ONRG-NICOP-N62909-18-1-2092 grant for funding this researchMuireann de h-Óra also thanks European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement number 861145–BeMAGIC for financial supportJudith L.MacManus-Driscoll also thanks the Royal Academy of Engineering Chair in Emerging Technologies grant-CIET1819\24 and the ERC grant EU-H2020-ERC-ADG#882929 EROS.
文摘The mid-T_(C) superconductor Ba1-XKXBiO3(BKBO)exhibits different superconducting mechanisms depending on x,in the range∼0.35–0.65.The optimal doping for the highest T_(C) is reported to be around x=0.4.To understand more about the dependence of the superconducting mechanism on x,high quality and reproducible epitaxial films with controlled x are needed.This has been challenging owing to the volatility of K and(to a lesser extent)Bi.In this work,we use pulsed laser deposition(PLD)with several novel process steps to achieve high-quality films in a reproducible way.These include a modified method for target preparation,a low NO_(2) growth pressure,and precise positioning of substrates in the PLD plume.Optimum T_(C) films(32 K onset)were grown from an x=0.4 target,i.e.with no excess K,as is normally used.Stable,higher K content films(made from an x=0.45 target),were also grown.These x=0.45 films had a lower T_(C) (22.5 K onset),as expected for(K)overdoped films,with very high upper critical field,H_(C2) (0 K),and irreversibility field,Hirr(0 K),values,from linear extrapolation,of∼31.7 T and∼28.8 T,respectively.The growth methodology demonstrated in this work is highly beneficial for fundamental mechanistic studies of this complex superconductor on which there is renewed interest,and where controlled compositions and crystalline quality are currently limited.
基金Supported in part by the Offices of NP and HEP within the U.S.DOE Office of Sciencethe U.S.NSF+18 种基金the Sloan Foundationthe DFG cluster of excellence‘Origin and Structure of the Universe’of Germany,CNRS/IN2P3STFC and EPSRC of the United KingdomFAPESP CNPq of Brazil,Ministry of Ed.Sci.of the Russian FederationNNSFCCASMoSTMoE of ChinaGA and MSMT of the Czech RepublicFOM and NWO of the NetherlandsDAEDSTCSIR of IndiaPolish Ministry of Sci.Higher Ed.,Korea Research Foundation,Ministry of Sci.,Ed.Sports of the Rep.Of CroatiaRussian Ministry of Sci.and TechRos-Atom of Russia。
文摘Dihadron azimuthal correlations containing a high transverse momentum(pr)trigger particle are sensit-ive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium,ie.jet-quenching.Previous measurements revealed a strong modification to di-hadron azimuthal correlations in Au+Au collisions with respect to ptp and d+Au collisions.The modification in-creases with the collision centrality,suggesting a path-length or energy density dependence to the je-quenching ef-fect.This paper reports STAR measurements of dihadron azimuthal correlations in mid-central(20%-60%)Au+Au collisions at√^(S)NN=200 GeV as a function of the trigger particle's azimuthal angle relative to the event plane,Ф_(s)=|Ф_(t)-ψ_(Ep)|.The azimuthal correlation is studied as a function of both the trigger and associated particle pr.The subtractions of the combinatorial background and anisotropic flow,assuming Zero Yield At Minimum(ZYAM),are described.The correlation results are first discussed with subtraction of the even harmonic(elliptic and quadrangu-lar)flow backgrounds.The away-side correlation is strongly modifed,and the modification varies withФ_(s),with a double-peak structure for out-of-plane trigger particles.The near-side ridge(long range pseudo-rapidity△_(η)correla-tion)appears to drop with increasingФ_(s)while the jet-like component remains approximately constant.The correla-tion functions are further studied with the subtraction of odd harmonic triangular flow background arising from fluc-tuations.It is found that the triangular flow,while responsible for the majority of the amplitudes,is not sufficient to explain theφs-dependence of the ridge or the away-side double-peak structure.The dropping ridge withФ_(s)could be attributed to aФ_(s)-dependent lliptie anisotropy;however,the physics mechanism of the ridge remains an open ques-tion.Even with aФ_(s)-dependent elliptic flow,the away-side correlation structure is robust.These results,with extens-ive systematic studies of the dihadron correlations as a function ofФ_(s),trigger and associated particle pT,and the pseudo-rapidity range△_(η),should provide stringent inputs to help understand the underlying physics mechanisms of jet-medium interactions in high energy nuclear collisions.
基金The authors would like to thank Catherine Zanotto and Mathieu Hemmerléfor their help in the experiments.This work was supported by the French National Research Agency in the framework of the“Investissements d’avenir”program AKER(ANR-11-BTBR-0007).
文摘Selection of sugar beet(Beta vulgaris L.)cultivars that are resistant to Cercospora Leaf Spot(CLS)disease is critical to increase yield.Such selection requires an automatic,fast,and objective method to assess CLS severity on thousands of cultivars in the field.For this purpose,we compare the use of submillimeter scale RGB imagery acquired from an Unmanned Ground Vehicle(UGV)under active illumination and centimeter scale multispectral imagery acquired from an Unmanned Aerial Vehicle(UAV)under passive illumination.Several variables are extracted from the images(spot density and spot size for UGV,green fraction for UGV and UAV)and related to visual scores assessed by an expert.Results show that spot density and green fraction are critical variables to assess low and high CLS severities,respectively,which emphasizes the importance of having submillimeter images to early detect CLS in field conditions.Genotype sensitivity to CLS can then be accurately retrieved based on time integrals of UGV-and UAV-derived scores.While UGV shows the best estimation performance,UAV can show accurate estimates of cultivar sensitivity if the data are properly acquired.Advantages and limitations of UGV,UAV,and visual scoring methods are finally discussed in the perspective of high-throughput phenotyping.
文摘High transverse momentum(pT)particle production is suppressed owing to the parton(jet)energy loss in the hot dense medium created in relativistic heavy-ion collisions.Redistribution of energy at low-to-modest pT has been difficult to measure,owing to large anisotropic backgrounds.We report a data-driven method for background evaluation and subtraction,exploiting the away-side pseudorapidity gaps,to measure the jetlike correlation shape in Au+Au collisions at √sNN=200 GeV in the STAR experiment.The correlation shapes,for trigger particles pT>3GeV/c and various associated particle pT ranges within 0.5<pT<10GeV/c,are consistent with Gaussians,and their widths increase with centrality.The results indicate jet broadening in the medium created in central heavy-ion collisions.
基金financially supported by Science and Technology Program of Guangzhou(No.202007020008)the National Natural Science Foundation of China(No.52001137)+2 种基金the Guangdong Academy of Sciences Program(No.2020GDASYL-20200104028)the Natural Science Foundation of Guangdong Province(No.2020A1515010948)the Guang Dong Basic and Applied Basic Research Foundation(No.2021A1515111065)
文摘The initial-stage oxidation behaviours of unmodified,Pt and Pt+Hf modified NiAl coating are systematically investigated by employing the photo-stimulated luminescence spectroscopy(PSLS)and transmission electron microscopy(TEM)technique.Both Pt and Hf additions can retard the θ-toα-Al_(2)O_(3)phase transformation.The oxidation rates of the modified NiAl coatings are initially higher than that of the unmodified NiAl coating due to the longer presence of θ-Al_(2)O_(3).However,they decrease drastically when the oxide in the scale turns to be α-Al_(2)O_(3)dominantly.The delayed phase transformation in the modified coatings results in lower residual stress within the oxide scale.
基金Supported by U.S.DOE Grants DE-AC02-98CH10886,DE-FG02-93ER40802,DE-FG02-94ER40818,DE-FG02-94ER40865,DE-FG02-99ER41099,and DE-AC02-06CH11357by U.S.NSF Grants 9603486,0072204,and 0245011+2 种基金by Polish KBN Grant 1-P03B-062-27 (2004-2007)by NSC of Taiwan Contract NSC 89-2112-M-008-024by Hungarian OTKA Grant F049823
文摘Recent measurements of event-by-event elliptic flow in Au+Au collisions at S_(NN)^(1/2)=200GeV exhibit large relative fluctuations of about 40%—50%.The data are well described by fluctuations in the shape of the initial collision region,as estimated event-by-event with the participant eccentricity using Glauber Monte Carlo.These results,combined with the demonstrated participant eccentricity scaling of the elliptic flow across nuclear species,constitute evidence of transverse granularity in the initial matter production in these collisions.
