Precipitation of multiple strong nanoprecipitates is crucial for the development of ultrahigh-strength structural materials with a strength of 2.5 GPa or above.Nevertheless,the ductility usually loses rapidly with str...Precipitation of multiple strong nanoprecipitates is crucial for the development of ultrahigh-strength structural materials with a strength of 2.5 GPa or above.Nevertheless,the ductility usually loses rapidly with strength due to limited dislocation mobility and high cracking tendency if coarse non-deformable precipitates are employed.Herein,we report a 2.5 GPa maraging steel strengthened by an ultrahigh den-sity of intermeshed shearable nanostructures consisting of Ni(Al,Fe)nanoprecipitates and Mo-rich(∼30 at.%)disordered clusters,both of which assume coherent interfaces.The fully coherent B2-Ni(Al,Fe)par-ticles precipitate in an extremely fast fashion,effectively accelerating local aggregation of low-diffusivity Mo atoms and promoting the formation of Mo-rich clusters surrounding them.This elemental partition was found to be further enhanced by Co addition via depleting both residual Al and Mo within the ma-trix,leading to the formation of copious yet fine intermeshed nanostructures.During plastic deformation,the interlocked nanostructures not only enhance local cutting stress by combining long-range elastic and short-range chemically ordering effects but also improve dislocation activity and resist shear-induced plastic instability.The multiple shearable nanostructures endow decent ductility(>6%)of the 2.5 GPa steel,suggesting a new paradigm for designing ultrastrong steels.展开更多
Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films...Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films have been investigated using optical spectroscopy, band structure analyses and ultraviolet photoelectro n spectroscopy (UPS). ZnO films have direct allowed transition band structure, w hich has been confirmed by the character of the optical absorption coefficient. The apparent band gap has been found directly proportional to N2/3, showing that the effect of Burstein-Moss shift on the band gap variations dominates over the many-body effect. With only standard cleaning protocols, the work function of ZnO: (Al, Mn) and ZnO: Al films have been measured to be 4.26 and 4.21eV, respec tively. The incorporation of Mn element into the matrix of ZnO, as a relatively deep donor, can remove some electrons from the conduction band and deplete the d ensity of occupied states at the Fermi energy, which causes a loss in measured p hotoemission intensity and an increase in the surface work function. Based on th e band gap and work function results, the energy band diagram of the ZnO: (Al, M n) film near its surface is also given.展开更多
The effect of La alloying on the crystalline characteristics, electrochemical capacity and activity of AB2 type Zr-Cr-Ni hydride electrodes was investigated. It was found that La alloying was able to shorten the activ...The effect of La alloying on the crystalline characteristics, electrochemical capacity and activity of AB2 type Zr-Cr-Ni hydride electrodes was investigated. It was found that La alloying was able to shorten the activating process from 15 cycles of La-free alloy to 2 cycles, and that the main phase shifts from C14 to C15 by XRD analysis. It may be attributed to the modification of surface chemical states and change in internal microstructures. However, the cycling stability was also found to degrade severely for La-containing hydride electrode because of the collapse of its distorted lattice.展开更多
We report the experimental results of the commissioning phase in the 10 PW laser beamline of the Shanghai Superintense Ultrafast Laser Facility(SULF).The peak power reaches 2.4 PW on target without the last amplifying...We report the experimental results of the commissioning phase in the 10 PW laser beamline of the Shanghai Superintense Ultrafast Laser Facility(SULF).The peak power reaches 2.4 PW on target without the last amplifying during the experiment.The laser energy of 72±9 J is directed to a focal spot of approximately 6μm diameter(full width at half maximum)in 30 fs pulse duration,yielding a focused peak intensity around 2.0×10^(21)W/cm^(2).The first laser-proton acceleration experiment is performed using plain copper and plastic targets.High-energy proton beams with maximum cut-off energy up to 62.5 MeV are achieved using copper foils at the optimum target thickness of 4μm via target normal sheath acceleration.For plastic targets of tens of nanometers thick,the proton cut-off energy is approximately 20 MeV,showing ring-like or flamented density distributions.These experimental results reflect the capabilities of the SULF-10 PW beamline,for example,both ultrahigh intensity and relatively good beam contrast.Further optimization for these key parameters is underway,where peak laser intensities of 10^(22)-10^(23)w/cm^(2)are anticipated to support various experiments on extreme field physics.展开更多
As a typical plasma-based optical element that can sustain ultra-high light intensity,plasma density gratings driven by intense laser pulses have been extensively studied for wide applications.Here,we show that the pl...As a typical plasma-based optical element that can sustain ultra-high light intensity,plasma density gratings driven by intense laser pulses have been extensively studied for wide applications.Here,we show that the plasma density grating driven by two intersecting driver laser pulses is not only nonuniform in space but also varies over time.Consequently,the probe laser pulse that passes through such a dynamic plasma density grating will be depolarized,that is,its polarization becomes spatially and temporally variable.More importantly,the laser depolarization may spontaneously take place for crossed laser beams if their polarization angles are arranged properly.The laser depolarization by a dynamic plasma density grating may find application in mitigating parametric instabilities in laser-driven inertial confinement fusion.展开更多
基金This research was supported by the National Key Research and Development Program of China(nos.2022YFB3705201 and 2022YFB4602101)National Natural Science Foundation of China(nos.51971018,U20B2025,11790293,52225103,51871016,51971017,52071024,52271003)+3 种基金the Funds for Creative Research Groups of NSFC(51921001)Projects of International Cooperation and Exchanges of NSFC(nos.51961160729,52061135207)111 Project(no.BP0719004)Program for Changjiang Scholars and In-novative Research Team in University of China(no.IRT_14R05),and the Fundamental Research Funds for the Central Universities of China:FRF-MP-20-43Z(JSH),FRF-TP-22-130A1(ZXB),FRF-TP-22-001C2(WY).
文摘Precipitation of multiple strong nanoprecipitates is crucial for the development of ultrahigh-strength structural materials with a strength of 2.5 GPa or above.Nevertheless,the ductility usually loses rapidly with strength due to limited dislocation mobility and high cracking tendency if coarse non-deformable precipitates are employed.Herein,we report a 2.5 GPa maraging steel strengthened by an ultrahigh den-sity of intermeshed shearable nanostructures consisting of Ni(Al,Fe)nanoprecipitates and Mo-rich(∼30 at.%)disordered clusters,both of which assume coherent interfaces.The fully coherent B2-Ni(Al,Fe)par-ticles precipitate in an extremely fast fashion,effectively accelerating local aggregation of low-diffusivity Mo atoms and promoting the formation of Mo-rich clusters surrounding them.This elemental partition was found to be further enhanced by Co addition via depleting both residual Al and Mo within the ma-trix,leading to the formation of copious yet fine intermeshed nanostructures.During plastic deformation,the interlocked nanostructures not only enhance local cutting stress by combining long-range elastic and short-range chemically ordering effects but also improve dislocation activity and resist shear-induced plastic instability.The multiple shearable nanostructures endow decent ductility(>6%)of the 2.5 GPa steel,suggesting a new paradigm for designing ultrastrong steels.
基金This work was supported by the National Nalural Science Foundation of China(No.50172051).
文摘Al and Mn co-doped-ZnO films have been prepared at room temperature by DC reacti ve magnetron sputtering technique. The optical absorption coefficient, apparent and fundamental band gap, and work function of the films have been investigated using optical spectroscopy, band structure analyses and ultraviolet photoelectro n spectroscopy (UPS). ZnO films have direct allowed transition band structure, w hich has been confirmed by the character of the optical absorption coefficient. The apparent band gap has been found directly proportional to N2/3, showing that the effect of Burstein-Moss shift on the band gap variations dominates over the many-body effect. With only standard cleaning protocols, the work function of ZnO: (Al, Mn) and ZnO: Al films have been measured to be 4.26 and 4.21eV, respec tively. The incorporation of Mn element into the matrix of ZnO, as a relatively deep donor, can remove some electrons from the conduction band and deplete the d ensity of occupied states at the Fermi energy, which causes a loss in measured p hotoemission intensity and an increase in the surface work function. Based on th e band gap and work function results, the energy band diagram of the ZnO: (Al, M n) film near its surface is also given.
文摘The effect of La alloying on the crystalline characteristics, electrochemical capacity and activity of AB2 type Zr-Cr-Ni hydride electrodes was investigated. It was found that La alloying was able to shorten the activating process from 15 cycles of La-free alloy to 2 cycles, and that the main phase shifts from C14 to C15 by XRD analysis. It may be attributed to the modification of surface chemical states and change in internal microstructures. However, the cycling stability was also found to degrade severely for La-containing hydride electrode because of the collapse of its distorted lattice.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB16)the National Natural Science Foundation of China(Nos.11875307,11935008,11804348,11705260,11905278 and 11975302)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2021242).
文摘We report the experimental results of the commissioning phase in the 10 PW laser beamline of the Shanghai Superintense Ultrafast Laser Facility(SULF).The peak power reaches 2.4 PW on target without the last amplifying during the experiment.The laser energy of 72±9 J is directed to a focal spot of approximately 6μm diameter(full width at half maximum)in 30 fs pulse duration,yielding a focused peak intensity around 2.0×10^(21)W/cm^(2).The first laser-proton acceleration experiment is performed using plain copper and plastic targets.High-energy proton beams with maximum cut-off energy up to 62.5 MeV are achieved using copper foils at the optimum target thickness of 4μm via target normal sheath acceleration.For plastic targets of tens of nanometers thick,the proton cut-off energy is approximately 20 MeV,showing ring-like or flamented density distributions.These experimental results reflect the capabilities of the SULF-10 PW beamline,for example,both ultrahigh intensity and relatively good beam contrast.Further optimization for these key parameters is underway,where peak laser intensities of 10^(22)-10^(23)w/cm^(2)are anticipated to support various experiments on extreme field physics.
基金supported by the National Natural Science Foundation of China(Grant Nos.11975154,11991074,12005287 and 12135009)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA25050100 and XDA25010100)+1 种基金the Presidential Foundation of the China Academy of Engineering Physics(Grant No.YZJJLX2016008)the Science Challenge Project(Grant No.TZ2018005).
文摘As a typical plasma-based optical element that can sustain ultra-high light intensity,plasma density gratings driven by intense laser pulses have been extensively studied for wide applications.Here,we show that the plasma density grating driven by two intersecting driver laser pulses is not only nonuniform in space but also varies over time.Consequently,the probe laser pulse that passes through such a dynamic plasma density grating will be depolarized,that is,its polarization becomes spatially and temporally variable.More importantly,the laser depolarization may spontaneously take place for crossed laser beams if their polarization angles are arranged properly.The laser depolarization by a dynamic plasma density grating may find application in mitigating parametric instabilities in laser-driven inertial confinement fusion.
