This paper is devoted to the images and preimages of D0 spaces.First of all,we prove that the preimage X of a D0 space Y under a perfect mapping f is a D0 space whenever X has a G^*-diagonal or every compact subset of...This paper is devoted to the images and preimages of D0 spaces.First of all,we prove that the preimage X of a D0 space Y under a perfect mapping f is a D0 space whenever X has a G^*-diagonal or every compact subset of Xif Gδ，And then we give a representation theorem of Dδ spaces.At last,we give a characterization of countably compact D0 spaces.展开更多
One of the key components of any grid architecture is managing compute and storage resources and optimizing their utilization.SAM has implemented features that allow it to exercise a "fair share" and "p...One of the key components of any grid architecture is managing compute and storage resources and optimizing their utilization.SAM has implemented features that allow it to exercise a "fair share" and "prioritized" policy among many groups of users.The goals are as follows:1)implement th experiments policies for resource usage by research group and by data access mode,and 2) optimize the resource usage to maximize the overall throughput defined in terms of real data processing activity,At the lowest level of SAM architecture,called the station,the SAM system integrates the data delivery and cache management with the job control and scheduling of the batch system.At the site-level,for example at Fermilab,requests for data from on-site stations are managed to optimize Mass Storage System resources and network throughput,Management of resources at a various geographic levels are discussed.展开更多
SAM is a network-distributed data management system developed at Fermilab for use with Run II data,It is being Employed by the D0 Experiment to store,manage,deliver,and track processing of all data.We describe the de...SAM is a network-distributed data management system developed at Fermilab for use with Run II data,It is being Employed by the D0 Experiment to store,manage,deliver,and track processing of all data.We describe the design and features of the system including resource management and data transfer mechanisms,We show the operational experience D0 has accumulated to date including data acquisition processing,and all levels of access and delivery.We present various configurations of the system and describe their use in the collaboration.展开更多
We report on the first operations of the reconstruction farms for the D0 experiment.Data were read from a tape robot to 50 PC's running Linux,processed,spooled to a central disk buffer for merging and then written...We report on the first operations of the reconstruction farms for the D0 experiment.Data were read from a tape robot to 50 PC's running Linux,processed,spooled to a central disk buffer for merging and then written back to the tape robot.The farms are being used successfully to reconstruct the data as it comes in.Transfer rates well over the 12.5 MB/sec needed for full data rates have been achieved.展开更多
Refractory high-entropy alloys have recently emerged as promising candidates for high-temperature structural applications.However,their performance is compromised by the trade-off required between strength and ductili...Refractory high-entropy alloys have recently emerged as promising candidates for high-temperature structural applications.However,their performance is compromised by the trade-off required between strength and ductility.Here,a novel W30Ta5(FeNi)65 refractory high-entropy alloy with an outstanding combination of strength and plasticity at both room and elevated temperatures is designed,based on the multi-phase transitions design strategy.The alloy comprises a body-centered cubic dendrite phase,a topologically close-packed μ rhombohedral phase,and a high-density coherent nano-precipitate γ"phase with the D0_(22)structure(Ni3Ta type)embedded in a continuous face-centered cubic matrix.Owing to pre-cipitation strengthening of D0_(22),the yield stress of the alloy is determined as high as 1450 MPa,which is a significant improvement(~100%)in comparison with the D0_(22)-free alloy,without a loss of ductil-ity.This alloy exhibits an excellent high-temperature strength,with the yield strengths of 1300 MPa at 600 ℃ and 320 MPa at 1000 ℃.Detailed microstructural characterization using transmission electron mi-croscopy,high-angle annular dark-field imaging,and three-dimensional atom probe tomography analyses indicated that this superior strength-plasticity combination stems from the synergy of a multiple-phase structure.These results provide a new insight into the design of RHEAs and other advanced alloys.展开更多
According to the physics of tokamak start-up,this study constructs a zero-dimensional(0D)model applicable to electron cyclotron(EC)wave assisted start-up in NCST spherical torus(spherical tokamak)and CN-H1 stellarator...According to the physics of tokamak start-up,this study constructs a zero-dimensional(0D)model applicable to electron cyclotron(EC)wave assisted start-up in NCST spherical torus(spherical tokamak)and CN-H1 stellarators.Using the constructed 0D model,the results obtained in this study under the same conditions are compared and validated against reference results for pure hydrogen plasma start-up in tokamak.The results are in good agreement,especially regarding electron temperature,ion temperature and plasma current.In the presence of finite Ohmic electric field in the spherical tokamak,a study on the EC wave assisted start-up of the NCST plasma at frequency of 28 GHz is conducted.The impact of the vertical magnetic field B_(v)on EC wave assisted start-up,the relationship between EC wave injection power P_(inj),Ohmic electric field E,and initial hydrogen atom density n_(H0)are explored separately.It is found that under conditions of Ohmic electric field lower than ITER(~0.3 V m^(-1)),EC wave can expand the operational space to achieve better plasma parameters.Simulating the process of28 GHz EC wave start-up in the CN-H1 stellarator plasma,the plasma current in the zerodimensional model is replaced with the current in the poloidal coil of the stellarator.Plasma startup can be successfully achieved at injection powers in the hundreds of kilowatts range,resulting in electron densities on the order of 10^(17)-10^(18)m^(-3).展开更多
To the Editor: Early infantile epileptic encephalopathy 23 (EIEE23;OMIM #615859) is a rare (<1/1,000,000 worldwide) kind of inherited autosomal recessive disorder. Patients with EIEE23 are characterized by in tract...To the Editor: Early infantile epileptic encephalopathy 23 (EIEE23;OMIM #615859) is a rare (<1/1,000,000 worldwide) kind of inherited autosomal recessive disorder. Patients with EIEE23 are characterized by in tractable seizures between 2 and 6 months of age.展开更多
文摘This paper is devoted to the images and preimages of D0 spaces.First of all,we prove that the preimage X of a D0 space Y under a perfect mapping f is a D0 space whenever X has a G^*-diagonal or every compact subset of Xif Gδ，And then we give a representation theorem of Dδ spaces.At last,we give a characterization of countably compact D0 spaces.
文摘One of the key components of any grid architecture is managing compute and storage resources and optimizing their utilization.SAM has implemented features that allow it to exercise a "fair share" and "prioritized" policy among many groups of users.The goals are as follows:1)implement th experiments policies for resource usage by research group and by data access mode,and 2) optimize the resource usage to maximize the overall throughput defined in terms of real data processing activity,At the lowest level of SAM architecture,called the station,the SAM system integrates the data delivery and cache management with the job control and scheduling of the batch system.At the site-level,for example at Fermilab,requests for data from on-site stations are managed to optimize Mass Storage System resources and network throughput,Management of resources at a various geographic levels are discussed.
文摘SAM is a network-distributed data management system developed at Fermilab for use with Run II data,It is being Employed by the D0 Experiment to store,manage,deliver,and track processing of all data.We describe the design and features of the system including resource management and data transfer mechanisms,We show the operational experience D0 has accumulated to date including data acquisition processing,and all levels of access and delivery.We present various configurations of the system and describe their use in the collaboration.
文摘We report on the first operations of the reconstruction farms for the D0 experiment.Data were read from a tape robot to 50 PC's running Linux,processed,spooled to a central disk buffer for merging and then written back to the tape robot.The farms are being used successfully to reconstruct the data as it comes in.Transfer rates well over the 12.5 MB/sec needed for full data rates have been achieved.
基金National Natural Science Foundation of China(Nos.11790292,11972346,12102433,U2141204 and 11988102)National Key Research and Development Program of China(No.2017YFB0702003)+4 种基金Strategic Priority Research Program(Nos.XDB22040302 and XDB22040303)Key Research Program of Frontier Sciences(No.QYZDJSSW-JSC011)Science Challenge Project(No.TZ2016001)Key Research Program of the Chinese Academy of Sciences(No.ZDRW-CN-2021-2-3)Opening Project of State Key Laboratory of Explosion Science and Technology(No.KFJJ21-01Z).
文摘Refractory high-entropy alloys have recently emerged as promising candidates for high-temperature structural applications.However,their performance is compromised by the trade-off required between strength and ductility.Here,a novel W30Ta5(FeNi)65 refractory high-entropy alloy with an outstanding combination of strength and plasticity at both room and elevated temperatures is designed,based on the multi-phase transitions design strategy.The alloy comprises a body-centered cubic dendrite phase,a topologically close-packed μ rhombohedral phase,and a high-density coherent nano-precipitate γ"phase with the D0_(22)structure(Ni3Ta type)embedded in a continuous face-centered cubic matrix.Owing to pre-cipitation strengthening of D0_(22),the yield stress of the alloy is determined as high as 1450 MPa,which is a significant improvement(~100%)in comparison with the D0_(22)-free alloy,without a loss of ductil-ity.This alloy exhibits an excellent high-temperature strength,with the yield strengths of 1300 MPa at 600 ℃ and 320 MPa at 1000 ℃.Detailed microstructural characterization using transmission electron mi-croscopy,high-angle annular dark-field imaging,and three-dimensional atom probe tomography analyses indicated that this superior strength-plasticity combination stems from the synergy of a multiple-phase structure.These results provide a new insight into the design of RHEAs and other advanced alloys.
基金supported by the National Key Research and Development Program of China(Nos.2022YFE03070000 and 2022YFE03070003)National Natural Science Foundation of China(Nos.12375220 and 12075114)。
文摘According to the physics of tokamak start-up,this study constructs a zero-dimensional(0D)model applicable to electron cyclotron(EC)wave assisted start-up in NCST spherical torus(spherical tokamak)and CN-H1 stellarators.Using the constructed 0D model,the results obtained in this study under the same conditions are compared and validated against reference results for pure hydrogen plasma start-up in tokamak.The results are in good agreement,especially regarding electron temperature,ion temperature and plasma current.In the presence of finite Ohmic electric field in the spherical tokamak,a study on the EC wave assisted start-up of the NCST plasma at frequency of 28 GHz is conducted.The impact of the vertical magnetic field B_(v)on EC wave assisted start-up,the relationship between EC wave injection power P_(inj),Ohmic electric field E,and initial hydrogen atom density n_(H0)are explored separately.It is found that under conditions of Ohmic electric field lower than ITER(~0.3 V m^(-1)),EC wave can expand the operational space to achieve better plasma parameters.Simulating the process of28 GHz EC wave start-up in the CN-H1 stellarator plasma,the plasma current in the zerodimensional model is replaced with the current in the poloidal coil of the stellarator.Plasma startup can be successfully achieved at injection powers in the hundreds of kilowatts range,resulting in electron densities on the order of 10^(17)-10^(18)m^(-3).
基金the China Postdoctoral Science Foundation (2016M602729 to B. B.)Health Technology Commission of Yunnan Province (2016NS235 to B.B.).
文摘To the Editor: Early infantile epileptic encephalopathy 23 (EIEE23;OMIM #615859) is a rare (<1/1,000,000 worldwide) kind of inherited autosomal recessive disorder. Patients with EIEE23 are characterized by in tractable seizures between 2 and 6 months of age.
