Effect of inner-surface roughness of conical target on laser absorption and fast electron generation

The effect of inner-surface roughness of conical targets on the generation of fast electrons in the laser-cone interaction is investigated using particle-in-cell simulation. It is found that the surface roughness can reduce the fast-electron number （in the energy range E 〉 1 MeV） and energy, as compared to that from a cone with smooth inner wall. A scaling law for the laser reflectivity based on the vacuum-heating model is derived. Both theory and simulation indicate that laser reflection increases with the height-to-width ratio of the periodic inner surface structure and approaches that of a smooth cone as this ratio becomes zero.

Fabrication of nanostructure in inner-surface of AISI 304 stainless steel pipe with surface plastic deformation

In the present investigation, a pipe inner-surface grinding（PISG） technique was developed to fabricate nanostructure in the inner-surface of an austenitic 304 stainless steel pipe. PISG was performed by high speed shearing with hard sphere tips, leading to gradient distribution of strain, strain rate and strain gradient along depth. Nano-austenite with an average boundary spacing of 20 nm was generated, followed by deformation microstructure characterized by shear bands, multi-and uni-directional twins and planar dislocation arrays. Deformation induced grain refinement of austenitic 304 stainless steel with low stacking fault energy（SFE） covering 4–5 order＇s magnitude of length scales toward nanometer regime was unified.

High proton conductivity in metalloring-cluster based metalorganic nanotubes

Two novel anionic single-walled metal-organic nanotubes(MONTs),[(CH_(3))_(2)NH_(2)][ln(cdc)(thb)].2DMF.9.5H_(2)O(FJU-105)and[(CH_(3))_(2)NH_(2)][ln(cdc)(H-btc)]-2DMA·11H_(2)O(FJU-106)(H_(2)cdc=9H-carbazole-3,6-dicarboxylic acid,H_(2)thb=2,5-thiophene dicarboxylic acid,H3btc=1,3,5-benzene tricarboxylic acid),are achieved by employing[ln_(6)(cdc)_(6)]^(6+)metalloring cluster with largest diameter as the secondary building blocks(SBUs).The inner surface of FJU-106 is functionalized by uncoordinated-COOH groups of the H-btc linkers,leading to a higher proton conduction than FJU-105.At 70℃,FJU-106 displays the proton conduction performances among MONTs,up to 1.80×10^(-2)S·cm(^-1).And FJU-105 and FJU-106 are the first examples of MONT proton conductors operating at subzero temperature.

On the microstructural evolution pattern toward nano-scale of an AISI 304 stainless steel during high strain rate surface deformation

In the present investigation,an austenitic AISI 304 stainless steel was subjected to high strain rate surface deformation by Pipe Inner-Surface Grinding(PISG)technique.The depth-dependent deformation parameters(strain,strain rate and strain gradient)were evaluated and the microstructures were systematically characterized.Microstructural evolution from millimeter-to nano-scale was explored,with special attention paid to the localized deformation.Microstructural evolution begins with the formation of planar dislocation arrays and the twin-matrix lamellae,which is followed by the localized deformation characterized by the initiation and the development of shear bands.A twinning-dominated process that was supplemented with dislocation slip-dominated one governed the microstructural evolution inside shear bands.The twin-matrix lamellae transform into extended/lamellar structure and finally the nanosized grains.Austenitic grains were substantially refined and martensitic transformation was effectively suppressed,of which the underlying mechanisms were analyzed.