目的探讨源于钆塞酸增强MRI的肝细胞摄取率是否与肝功能的定量测量有关,并帮助识别大范围肝切除术的禁忌证。材料与方法在2016年8月—2016年10月期间,纳入50例患有慢性肝病或肝硬化的受试者进行3.0 T MRI肝脏检查,包括T1 mapping和弹性...目的探讨源于钆塞酸增强MRI的肝细胞摄取率是否与肝功能的定量测量有关,并帮助识别大范围肝切除术的禁忌证。材料与方法在2016年8月—2016年10月期间,纳入50例患有慢性肝病或肝硬化的受试者进行3.0 T MRI肝脏检查,包括T1 mapping和弹性成像。展开更多
Precipitation strengthening provides one of the most widely-used mechanisms for strengthen-ing multi-principal-element alloys(MPEAs).Here,we report dual-morphology B2 precipitates in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)...Precipitation strengthening provides one of the most widely-used mechanisms for strengthen-ing multi-principal-element alloys(MPEAs).Here,we report dual-morphology B2 precipitates in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)Ti_(4)Mo_(1)MPEA obtained by thermo-mechanical processing.Electron microscopy charac-terization reveals that the dual-morphology B2 precipitates are either recrystallized B2 particles formed at the grain boundaries or triple junctions with recrystallization process,or rod-like within the non-recrystallized FCC matrix.The dual-morphology B2 precipitates enhance the yield strength and ultimate tensile strength up to 1120 MPa and 1480 MPa,respectively.This work suggests the mechanical proper-ties of the alloy can be optimized by B2 precipitation strengthening to meet the needs of engineering applications.展开更多
Tungsten powder was fabricated from the system CaWO4-Mg by self-propagating high-temperature synthesis (SHS) with a magnesium thermit stage. The physic-chemical change during heating and the effects of pressure of sam...Tungsten powder was fabricated from the system CaWO4-Mg by self-propagating high-temperature synthesis (SHS) with a magnesium thermit stage. The physic-chemical change during heating and the effects of pressure of sample and diluents (W powder) on product have been studied. The experimental results show that the porosity of combustion product and the particle size of final tungsten powder decrease with increasing pressure of sample. Addition of diluents could increase the particle size of final tungsten powder. The purity of tungsten is improved by leaching in NaOH solution. The results of spectral analysis and particle size distribution of final tungsten powder show that the final Tungsten powder has a median diameter of 0.87μm,specific surface area of 1.09m2/g and purity of above 99.0%.展开更多
We report a detailed study of polarization characteristics and subpulse drifting in PSR J1110-5637 with the observations of the Parkes 64 m radio telescope at 1369 MHz.The observations revealed that the trailing compo...We report a detailed study of polarization characteristics and subpulse drifting in PSR J1110-5637 with the observations of the Parkes 64 m radio telescope at 1369 MHz.The observations revealed that the trailing component of the pulse profile has obvious subpulse drifting,while the leading component has no subpulse drifting.Using the two-dimensional fluctuation spectrum(2DFS),we detected three distinct emission modes in the trailing component(modes A,B and C).The emission in mode A is chaotic and indistinguishable,while modes B and C have obvious subpulse drifting.The vertical modulation periods P3of modes B and C are around the mean values of 12 P and 8 P,respectively.The subpulse drifting of PSR J1110-5637 will expand the pulsar sample with multiple subpulse drifting rates,and this will help future systematic studies on the physical origin of the subpulse drifting phenomenon.展开更多
基金supported by the Central Guidance on Local Science and Technology Development Fund of Hebei Province(No.216Z1012G)the National Natural Science Foundation of China(No.12174274).
文摘Precipitation strengthening provides one of the most widely-used mechanisms for strengthen-ing multi-principal-element alloys(MPEAs).Here,we report dual-morphology B2 precipitates in Co_(36)Cr_(15)Fe_(18)Ni_(18)Al_(8)Ti_(4)Mo_(1)MPEA obtained by thermo-mechanical processing.Electron microscopy charac-terization reveals that the dual-morphology B2 precipitates are either recrystallized B2 particles formed at the grain boundaries or triple junctions with recrystallization process,or rod-like within the non-recrystallized FCC matrix.The dual-morphology B2 precipitates enhance the yield strength and ultimate tensile strength up to 1120 MPa and 1480 MPa,respectively.This work suggests the mechanical proper-ties of the alloy can be optimized by B2 precipitation strengthening to meet the needs of engineering applications.
文摘Tungsten powder was fabricated from the system CaWO4-Mg by self-propagating high-temperature synthesis (SHS) with a magnesium thermit stage. The physic-chemical change during heating and the effects of pressure of sample and diluents (W powder) on product have been studied. The experimental results show that the porosity of combustion product and the particle size of final tungsten powder decrease with increasing pressure of sample. Addition of diluents could increase the particle size of final tungsten powder. The purity of tungsten is improved by leaching in NaOH solution. The results of spectral analysis and particle size distribution of final tungsten powder show that the final Tungsten powder has a median diameter of 0.87μm,specific surface area of 1.09m2/g and purity of above 99.0%.
基金supported by Guizhou Province Science and Technology Foundation(No.ZK[2022]304)the National Natural Science Foundation of China(Nos.U1731238,11565010,12103013 and U1831120)+1 种基金the Foundation of Guizhou Provincial Education Department(No.KY(2020)003 and KY(2021)303)The Parkes radio telescope is part of the Australia Telescope National Facility which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO。
文摘We report a detailed study of polarization characteristics and subpulse drifting in PSR J1110-5637 with the observations of the Parkes 64 m radio telescope at 1369 MHz.The observations revealed that the trailing component of the pulse profile has obvious subpulse drifting,while the leading component has no subpulse drifting.Using the two-dimensional fluctuation spectrum(2DFS),we detected three distinct emission modes in the trailing component(modes A,B and C).The emission in mode A is chaotic and indistinguishable,while modes B and C have obvious subpulse drifting.The vertical modulation periods P3of modes B and C are around the mean values of 12 P and 8 P,respectively.The subpulse drifting of PSR J1110-5637 will expand the pulsar sample with multiple subpulse drifting rates,and this will help future systematic studies on the physical origin of the subpulse drifting phenomenon.
