The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,a...The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,and added value for aircraft.Through the past decades,remarkable advances have been achieved in manufacturing technologies for conformal windows,where the machining accuracy approaches the nanometer level,and the surface form becomes more complex.These advances are critical to aircraft development,and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining field.In this review,the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their performances.The remarkable advances and concrete work accomplished by researchers are reviewed.The challenges in manufacturing conformal windows that should be faced in the future are discussed.展开更多
The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the ...The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring.The full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target values.These milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam commissioning.As measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,respectively.This paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.展开更多
BACKGROUND Thrombocytopenia is common in patients with sepsis and septic shock.AIM To analyse the decrease in the number of platelets for predicting bloodstream infection in patients with sepsis and septic shock in th...BACKGROUND Thrombocytopenia is common in patients with sepsis and septic shock.AIM To analyse the decrease in the number of platelets for predicting bloodstream infection in patients with sepsis and septic shock in the intensive care unit.METHODS A retrospective analysis of patients admitted with sepsis and septic shock in Xingtai People Hospital was revisited.Patient population characteristics and laboratory data were collected for analysis.RESULTS The study group consisted of 85(39%)inpatients with bloodstream infection,and the control group consisted of 133(61%)with negative results or contamination.The percentage decline in platelet counts(PPCs)in patients positive for pathogens[57.1(41.3-74.6)]was distinctly higher than that in the control group[18.2(5.1–43.1)](P<0.001),whereas the PPCs were not significantly different among those with gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.Using receiver operating characteristic curves,the area under the curve of the platelet drop rate was 0.839(95%CI:0.783-0.895).CONCLUSION The percentage decline in platelet counts is sensitive in predicting bloodstream infection in patients with sepsis and septic shock.However,it cannot identify gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.展开更多
In the past decade,boron neutron capture therapy utilizing an accelerator-based neutron source(ABNS)designed primarily for producing epithermal neutrons has been implemented in the treatment of brain tumors and other ...In the past decade,boron neutron capture therapy utilizing an accelerator-based neutron source(ABNS)designed primarily for producing epithermal neutrons has been implemented in the treatment of brain tumors and other cancers.The specifications for designing an epithermal beam are primarily based on the IAEA-TECODC-1223 report,issued in 2001 for reactor neutron sources.Based on this report,the latest perspectives and clinical requirements,we designed an ABNS capable of adjusting the average neutron beam energy.The design was based on a 2.8 MeV,20 mA proton beam bombarding a lithium target to produce neutrons that were subsequently moderated and tuned through a tunable beam shaping assembly(BSA)which can modify the thicknesses and materials of the coin-shaped moderators,back reflectors,filters,and collimators.The simulation results demonstrated that epithermal neutron beams for deep seated tumor treatment,which were generated by utilizing magnesium fluoride with lengths ranging between 28 and 36 cm as the moderator,possessed a treatment depth of 5.6 cm although the neutron flux peak shifts from 4.5 to 1.0 keV.When utilizing a thinner moderator,a less accelerated beam power can meet the treatment requirements.However,higher powers reduced the treatment time.In contrast,employing a thick moderator can reduce the skin dose.In scenarios that required relatively low energy neutron beams,the removal of the thermal neutron filter can raise the thermal neutron flux at the beam port.And the depth of the dose rate peak could be adjusted between 0.25 and 2.20 cm by combining magnesium fluoride and polyethylene coins of different thicknesses.Hence,this device has a better adaptability for the treatment of superficial tumors.Overall,the tunable BSA provides greater flexibility for clinical treatment than common BSA designs that can only adjust the port size.展开更多
Ultrasonic guided wave is an attractive monitoring technique for large-scale structures but is vulnerable to changes in environmental and operational conditions(EOC),which are inevitable in the normal inspection of ci...Ultrasonic guided wave is an attractive monitoring technique for large-scale structures but is vulnerable to changes in environmental and operational conditions(EOC),which are inevitable in the normal inspection of civil and mechanical structures.This paper thus presents a robust guided wave-based method for damage detection and localization under complex environmental conditions by singular value decomposition-based feature extraction and one-dimensional convolutional neural network(1D-CNN).After singular value decomposition-based feature extraction processing,a temporal robust damage index(TRDI)is extracted,and the effect of EOCs is well removed.Hence,even for the signals with a very large temperature-varying range and low signal-to-noise ratios(SNRs),the final damage detection and localization accuracy retain perfect 100%.Verifications are conducted on two different experimental datasets.The first dataset consists of guided wave signals collected from a thin aluminum plate with artificial noises,and the second is a publicly available experimental dataset of guided wave signals acquired on a composite plate with a temperature ranging from 20℃to 60℃.It is demonstrated that the proposed method can detect and localize the damage accurately and rapidly,showing great potential for application in complex and unknown EOC.展开更多
Mobile Edge Computing(MEC)and 5G technology allow clients to access computing resources at the network frontier,which paves the way for applying Mobile Augmented Reality(MAR)applications.Under the MEC paradigm,MAR cli...Mobile Edge Computing(MEC)and 5G technology allow clients to access computing resources at the network frontier,which paves the way for applying Mobile Augmented Reality(MAR)applications.Under the MEC paradigm,MAR clients can offload complex tasks to the MEC server and enhance the human perception of the world by merging the received virtual information with the real environment.However,the resource allocation problem arises as a critical challenge in circumstances where several MAR clients compete for limited resources at the network frontier.In this paper,we aim to design an online resource allocation scheme on the MEC server that takes both high quality of experience and good fairness performance for MAR clients into consideration.We first formulate this problem as a Markov decision process and tackle the challenge of applying the deep reinforcement learning paradigm.Then,we propose DRAM,a Deep reinforcement learning-based Resource allocation scheme for mobile Augmented reality service in MEC.We also propose a self-adaptive algorithm on the MAR client that is derived based on the analysis of the MAR service to tackle client adaptation problems.The simulation results demonstrated that DRAM can provide high quality of experience and simultaneously achieve good fairness performance by coordinating with clients’adaptation algorithms.展开更多
Recently discovered kagome metals AV_(3)Sb_(5)(A=K,Rb,and Cs)provide an ideal platform to study the correlation among nontrivial band topology,unconventional charge density wave(CDW),and superconductivity.The evolutio...Recently discovered kagome metals AV_(3)Sb_(5)(A=K,Rb,and Cs)provide an ideal platform to study the correlation among nontrivial band topology,unconventional charge density wave(CDW),and superconductivity.The evolution of electronic structures associated with the change of lattice modulations is crucial for understanding of the CDW mechanism,with the combination of angle-resolved photoemission spectroscopy(ARPES)measurements and density functional theory calculations,we investigate how band dispersions change with the increase of lattice distortions.In particular,we focus on the electronic states around M point,where the van Hove singularities are expected to play crucial roles in the CDW transition.Previous ARPES studies reported a spectral weight splitting of the van Hove singularity around M point,which is associated with the 3D lattice modulations.Our studies reveal that this“splitting”can be connected to the two van Hove singularities at k_(z)=0 and k_(z)=π/c in the normal states.When the electronic system enters into the CDW state,both van Hove singularities move down.Such novel properties are important for understanding of the CDW transition.展开更多
Soil salinity is a growing concern for global crop production and the sustainable development of humanity.Therefore,it is crucial to comprehend salt tolerance mechanisms and identify salt-tolerance genes to enhance cr...Soil salinity is a growing concern for global crop production and the sustainable development of humanity.Therefore,it is crucial to comprehend salt tolerance mechanisms and identify salt-tolerance genes to enhance crop tolerance to salt stress.Suaeda glauca,a halophyte species well adapted to the seawater environment,possesses a unique ability to absorb and retain high salt concentrations within its cells,particularly in its leaves,suggesting the presence of a distinct mechanism for salt tolerance.In this study,we performed de novo sequencing of the S.glauca genome.The genome has a size of 1.02 Gb(consisting of two sets of haplotypes)and contains 54761 annotated genes,including alleles and repeats.Comparative genomic analysis revealed a strong synteny between the genomes of S.glauca and Beta vulgaris.Of the S.glauca genome,70.56%comprises repeat sequences,with retroelements being the most abundant.Leveraging the allele-aware assembly of the S.glauca genome,we investigated genome-wide allele-specific expression in the analyzed samples.The results indicated that the diversity in promoter sequences might contribute to consistent allele-specific expression.Moreover,a systematic analysis of the ABCE gene families shed light on the formation of S.glauca’s flower morphology,suggesting that dysfunction of A-class genes is responsible for the absence of petals in S.glauca.Gene family expansion analysis demonstrated significant enrichment of Gene Ontology(GO)terms associated with DNA repair,chromosome stability,DNA demethylation,cation binding,and red/far-red light signaling pathways in the co-expanded gene families of S.glauca and S.aralocaspica,in comparison with glycophytic species within the chenopodium family.Time-course transcriptome analysis under salt treatments revealed detailed responses of S.glauca to salt tolerance,and the enrichment of the transition-upregulated genes in the leaves associated with DNA repair and chromosome stability,lipid biosynthetic process,and isoprenoid metabolic process.Additionally,genome-wide analysis of transcription factors indicated a significant expansion of FAR1 gene family.However,further investigation is needed to determine the exact role of the FAR1 gene family in salt tolerance in S.glauca.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.52206222,No.22227901)State Key Laboratory of Laser Interaction with Matter Foundation(SKLLIM2009).
基金the support from the National Key Research and Development Program of China[2018YFA0703400].
文摘The infrared conformal window is one of the most critical components in aircraft.Conformal windows with high performance bring low aberrations,high aerodynamic performance,reliability in extreme working environments,and added value for aircraft.Through the past decades,remarkable advances have been achieved in manufacturing technologies for conformal windows,where the machining accuracy approaches the nanometer level,and the surface form becomes more complex.These advances are critical to aircraft development,and these manufacturing technologies also have significant reference values for other directions of the ultra-precision machining field.In this review,the infrared materials suitable for manufacturing conformal windows are introduced and compared with insights into their performances.The remarkable advances and concrete work accomplished by researchers are reviewed.The challenges in manufacturing conformal windows that should be faced in the future are discussed.
基金This work was supported by the National Natural Science Foundation of China(No.12005239).
文摘The high-energy photon source(HEPS)is the first fourth-generation synchrotron light source facility in China.The HEPS injector consists of a linear accelerator(Linac)and a full energy booster.The booster captures the electron beam from the Linac and increases its energy to the value required for the storage ring.The full-energy beam could be injected to the storage ring directly or after“high-energy accumulation.”On November 17,2023,the key booster parameters successfully reached their corresponding target values.These milestone results were achieved based on numerous contributions,including nearly a decade of physical design,years of equipment development and installation,and months of beam commissioning.As measured at the extraction energy of 6 GeV,the averaged beam current and emittance reached 8.57 mA with 5 bunches and 30.37 nm rad with a single-bunch charge of 5.58 nC,compared with the corresponding target values of 6.6 mA and 35 nm rad,respectively.This paper presents the physical design,equipment development,installation,and commissioning process of the HEPS booster.
文摘BACKGROUND Thrombocytopenia is common in patients with sepsis and septic shock.AIM To analyse the decrease in the number of platelets for predicting bloodstream infection in patients with sepsis and septic shock in the intensive care unit.METHODS A retrospective analysis of patients admitted with sepsis and septic shock in Xingtai People Hospital was revisited.Patient population characteristics and laboratory data were collected for analysis.RESULTS The study group consisted of 85(39%)inpatients with bloodstream infection,and the control group consisted of 133(61%)with negative results or contamination.The percentage decline in platelet counts(PPCs)in patients positive for pathogens[57.1(41.3-74.6)]was distinctly higher than that in the control group[18.2(5.1–43.1)](P<0.001),whereas the PPCs were not significantly different among those with gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.Using receiver operating characteristic curves,the area under the curve of the platelet drop rate was 0.839(95%CI:0.783-0.895).CONCLUSION The percentage decline in platelet counts is sensitive in predicting bloodstream infection in patients with sepsis and septic shock.However,it cannot identify gram-positive bacteraemia,gram-negative bacteraemia,and fungal infection.
基金supported by the National Natural Science Foundation of China (12132016, 11972032, 12172349)USTC Research Funds of the Double First-Class Initiative (YD2480002004)+1 种基金the Fundamental Research Funds for the Central Universities (WK2480000007)USTC Center for Micro- and Nanoscale Research and Fabrication。
基金supported by the National Nature Science Foundation of China(No.1210050454)the program of Chinese Scholarship Council(No.202106280126)。
文摘In the past decade,boron neutron capture therapy utilizing an accelerator-based neutron source(ABNS)designed primarily for producing epithermal neutrons has been implemented in the treatment of brain tumors and other cancers.The specifications for designing an epithermal beam are primarily based on the IAEA-TECODC-1223 report,issued in 2001 for reactor neutron sources.Based on this report,the latest perspectives and clinical requirements,we designed an ABNS capable of adjusting the average neutron beam energy.The design was based on a 2.8 MeV,20 mA proton beam bombarding a lithium target to produce neutrons that were subsequently moderated and tuned through a tunable beam shaping assembly(BSA)which can modify the thicknesses and materials of the coin-shaped moderators,back reflectors,filters,and collimators.The simulation results demonstrated that epithermal neutron beams for deep seated tumor treatment,which were generated by utilizing magnesium fluoride with lengths ranging between 28 and 36 cm as the moderator,possessed a treatment depth of 5.6 cm although the neutron flux peak shifts from 4.5 to 1.0 keV.When utilizing a thinner moderator,a less accelerated beam power can meet the treatment requirements.However,higher powers reduced the treatment time.In contrast,employing a thick moderator can reduce the skin dose.In scenarios that required relatively low energy neutron beams,the removal of the thermal neutron filter can raise the thermal neutron flux at the beam port.And the depth of the dose rate peak could be adjusted between 0.25 and 2.20 cm by combining magnesium fluoride and polyethylene coins of different thicknesses.Hence,this device has a better adaptability for the treatment of superficial tumors.Overall,the tunable BSA provides greater flexibility for clinical treatment than common BSA designs that can only adjust the port size.
基金financially supported in part by the National Key R&D Program of China (2020YFA0406103)the National Natural Science Foundation of China (21725102, 22122506, 91961106, 22075267, 22109148)+4 种基金Strategic Priority Research Program of the Chinese Academy of Sciences (XDPB14)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (2019444)the Hundred Talents Program of the Chinese Academy of SciencesFundamental Research Funds for the Central Universities (WK2060000039)support from the USTC Center for Micro- and Nanoscale Research and Fabrication。
基金Supported by National Natural Science Foundation of China(Grant Nos.52272433 and 11874110)Jiangsu Provincial Key R&D Program(Grant No.BE2021084)Technical Support Special Project of State Administration for Market Regulation(Grant No.2022YJ11).
文摘Ultrasonic guided wave is an attractive monitoring technique for large-scale structures but is vulnerable to changes in environmental and operational conditions(EOC),which are inevitable in the normal inspection of civil and mechanical structures.This paper thus presents a robust guided wave-based method for damage detection and localization under complex environmental conditions by singular value decomposition-based feature extraction and one-dimensional convolutional neural network(1D-CNN).After singular value decomposition-based feature extraction processing,a temporal robust damage index(TRDI)is extracted,and the effect of EOCs is well removed.Hence,even for the signals with a very large temperature-varying range and low signal-to-noise ratios(SNRs),the final damage detection and localization accuracy retain perfect 100%.Verifications are conducted on two different experimental datasets.The first dataset consists of guided wave signals collected from a thin aluminum plate with artificial noises,and the second is a publicly available experimental dataset of guided wave signals acquired on a composite plate with a temperature ranging from 20℃to 60℃.It is demonstrated that the proposed method can detect and localize the damage accurately and rapidly,showing great potential for application in complex and unknown EOC.
基金supported by the National Key R&D Program of China(2020YFB1807804,2020YFB1807800)the National Nat-ural Science Foundation of China(NSFC)(62001087,62072079,U20A20156).
文摘Mobile Edge Computing(MEC)and 5G technology allow clients to access computing resources at the network frontier,which paves the way for applying Mobile Augmented Reality(MAR)applications.Under the MEC paradigm,MAR clients can offload complex tasks to the MEC server and enhance the human perception of the world by merging the received virtual information with the real environment.However,the resource allocation problem arises as a critical challenge in circumstances where several MAR clients compete for limited resources at the network frontier.In this paper,we aim to design an online resource allocation scheme on the MEC server that takes both high quality of experience and good fairness performance for MAR clients into consideration.We first formulate this problem as a Markov decision process and tackle the challenge of applying the deep reinforcement learning paradigm.Then,we propose DRAM,a Deep reinforcement learning-based Resource allocation scheme for mobile Augmented reality service in MEC.We also propose a self-adaptive algorithm on the MAR client that is derived based on the analysis of the MAR service to tackle client adaptation problems.The simulation results demonstrated that DRAM can provide high quality of experience and simultaneously achieve good fairness performance by coordinating with clients’adaptation algorithms.
基金supported by the National Key R&D Program of China (Grant No.2017YFA0402901)the National Natural Science Foundation of China (Grant No.U2032153)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDB25000000)the Users with Excellence Program of Hefei Science Center of the Chinese Academy of Sciences (Grant No.2021HSC-UE004)。
文摘Recently discovered kagome metals AV_(3)Sb_(5)(A=K,Rb,and Cs)provide an ideal platform to study the correlation among nontrivial band topology,unconventional charge density wave(CDW),and superconductivity.The evolution of electronic structures associated with the change of lattice modulations is crucial for understanding of the CDW mechanism,with the combination of angle-resolved photoemission spectroscopy(ARPES)measurements and density functional theory calculations,we investigate how band dispersions change with the increase of lattice distortions.In particular,we focus on the electronic states around M point,where the van Hove singularities are expected to play crucial roles in the CDW transition.Previous ARPES studies reported a spectral weight splitting of the van Hove singularity around M point,which is associated with the 3D lattice modulations.Our studies reveal that this“splitting”can be connected to the two van Hove singularities at k_(z)=0 and k_(z)=π/c in the normal states.When the electronic system enters into the CDW state,both van Hove singularities move down.Such novel properties are important for understanding of the CDW transition.
基金supported by the National Natural Science Foundation of China(32170380)the Science and Technology Innovation Project of Pingtan Institute of Science and Technology(PT2021001)the Postdoctoral Foundation of China(2018 M642550).
文摘Soil salinity is a growing concern for global crop production and the sustainable development of humanity.Therefore,it is crucial to comprehend salt tolerance mechanisms and identify salt-tolerance genes to enhance crop tolerance to salt stress.Suaeda glauca,a halophyte species well adapted to the seawater environment,possesses a unique ability to absorb and retain high salt concentrations within its cells,particularly in its leaves,suggesting the presence of a distinct mechanism for salt tolerance.In this study,we performed de novo sequencing of the S.glauca genome.The genome has a size of 1.02 Gb(consisting of two sets of haplotypes)and contains 54761 annotated genes,including alleles and repeats.Comparative genomic analysis revealed a strong synteny between the genomes of S.glauca and Beta vulgaris.Of the S.glauca genome,70.56%comprises repeat sequences,with retroelements being the most abundant.Leveraging the allele-aware assembly of the S.glauca genome,we investigated genome-wide allele-specific expression in the analyzed samples.The results indicated that the diversity in promoter sequences might contribute to consistent allele-specific expression.Moreover,a systematic analysis of the ABCE gene families shed light on the formation of S.glauca’s flower morphology,suggesting that dysfunction of A-class genes is responsible for the absence of petals in S.glauca.Gene family expansion analysis demonstrated significant enrichment of Gene Ontology(GO)terms associated with DNA repair,chromosome stability,DNA demethylation,cation binding,and red/far-red light signaling pathways in the co-expanded gene families of S.glauca and S.aralocaspica,in comparison with glycophytic species within the chenopodium family.Time-course transcriptome analysis under salt treatments revealed detailed responses of S.glauca to salt tolerance,and the enrichment of the transition-upregulated genes in the leaves associated with DNA repair and chromosome stability,lipid biosynthetic process,and isoprenoid metabolic process.Additionally,genome-wide analysis of transcription factors indicated a significant expansion of FAR1 gene family.However,further investigation is needed to determine the exact role of the FAR1 gene family in salt tolerance in S.glauca.
