In this work,we introduce a roll-to-roll system that can continuously print three-dimensional(3D)periodic nanostructures over large areas.This approach is based on Langmuir-Blodgett assembly of colloidal nanospheres,w...In this work,we introduce a roll-to-roll system that can continuously print three-dimensional(3D)periodic nanostructures over large areas.This approach is based on Langmuir-Blodgett assembly of colloidal nanospheres,which diffract normal incident light to create a complex intensity pattern for near-field nanolithography.The geometry of the 3D nanostructure is defined by the Talbot effect and can be precisely designed by tuning the ratio of the nanosphere diameter to the exposure wavelength.Using this system,we have demonstrated patterning of 3D photonic crystals with a 500 nm period on a 50×200 mm^(2) flexible substrate,with a system throughput of 3mm/s.The patterning yield is quantitatively analyzed by an automated electron beam inspection method,demonstrating long-term repeatability of an up to 88% yield over a 4-month period.The inspection method can also be employed to examine pattern uniformity,achieving an average yield of up to 78.6% over full substrate areas.The proposed patterning method is highly versatile and scalable as a nanomanufacturing platform and can find application in nanophotonics,nanoarchitected materials,and multifunctional nanostructures.展开更多
VCSEL Injection locking is demonstrated to increase laser bandwidth and reduce non-linearity and chirp. All these properties enhance analog and digital modulation performance.
Several recently developed AUSM-family numerical flux functions(SLAU,SLAU2,AUSM+-up2,and AUSMPW+)have been successfully extended to compute compressible multiphase flows,based on the stratified flow model concept,by f...Several recently developed AUSM-family numerical flux functions(SLAU,SLAU2,AUSM+-up2,and AUSMPW+)have been successfully extended to compute compressible multiphase flows,based on the stratified flow model concept,by following two previous works:one by M.-S.Liou,C.-H.Chang,L.Nguyen,and T.G.Theofanous[AIAA J.46:2345-2356,2008],in which AUSM+-up was used entirely,and the other by C.-H.Chang,and M.-S.Liou[J.Comput.Phys.225:840-873,2007],in which the exact Riemann solver was combined into AUSM+-up at the phase interface.Through an extensive survey by comparing flux functions,the following are found:(1)AUSM+-up with dissipation parameters of Kp and Ku equal to 0.5 or greater,AUSMPW+,SLAU2,AUSM+-up2,and SLAU can be used to solve benchmark problems,including a shock/water-droplet interaction;(2)SLAU shows oscillatory behaviors[though not as catastrophic as those of AUSM+(a special case of AUSM+-up with Kp=Ku=0)]due to insufficient dissipation arising from its ideal-gas-based dissipation term;and(3)when combined with the exact Riemann solver,AUSM+-up(Kp=Ku=1),SLAU2,and AUSMPW+are applicable to more challenging problems with high pressure ratios.展开更多
基金This work was supported by the National Science Foundation(NSF)under grant CMMI#1552424.
文摘In this work,we introduce a roll-to-roll system that can continuously print three-dimensional(3D)periodic nanostructures over large areas.This approach is based on Langmuir-Blodgett assembly of colloidal nanospheres,which diffract normal incident light to create a complex intensity pattern for near-field nanolithography.The geometry of the 3D nanostructure is defined by the Talbot effect and can be precisely designed by tuning the ratio of the nanosphere diameter to the exposure wavelength.Using this system,we have demonstrated patterning of 3D photonic crystals with a 500 nm period on a 50×200 mm^(2) flexible substrate,with a system throughput of 3mm/s.The patterning yield is quantitatively analyzed by an automated electron beam inspection method,demonstrating long-term repeatability of an up to 88% yield over a 4-month period.The inspection method can also be employed to examine pattern uniformity,achieving an average yield of up to 78.6% over full substrate areas.The proposed patterning method is highly versatile and scalable as a nanomanufacturing platform and can find application in nanophotonics,nanoarchitected materials,and multifunctional nanostructures.
文摘VCSEL Injection locking is demonstrated to increase laser bandwidth and reduce non-linearity and chirp. All these properties enhance analog and digital modulation performance.
文摘Several recently developed AUSM-family numerical flux functions(SLAU,SLAU2,AUSM+-up2,and AUSMPW+)have been successfully extended to compute compressible multiphase flows,based on the stratified flow model concept,by following two previous works:one by M.-S.Liou,C.-H.Chang,L.Nguyen,and T.G.Theofanous[AIAA J.46:2345-2356,2008],in which AUSM+-up was used entirely,and the other by C.-H.Chang,and M.-S.Liou[J.Comput.Phys.225:840-873,2007],in which the exact Riemann solver was combined into AUSM+-up at the phase interface.Through an extensive survey by comparing flux functions,the following are found:(1)AUSM+-up with dissipation parameters of Kp and Ku equal to 0.5 or greater,AUSMPW+,SLAU2,AUSM+-up2,and SLAU can be used to solve benchmark problems,including a shock/water-droplet interaction;(2)SLAU shows oscillatory behaviors[though not as catastrophic as those of AUSM+(a special case of AUSM+-up with Kp=Ku=0)]due to insufficient dissipation arising from its ideal-gas-based dissipation term;and(3)when combined with the exact Riemann solver,AUSM+-up(Kp=Ku=1),SLAU2,and AUSMPW+are applicable to more challenging problems with high pressure ratios.
