A friction model was established for impulse control design in a precision control system. First, the physical characteristics of the impulse in momentum, such as motion and energy, were analyzed and formulated. Then,...A friction model was established for impulse control design in a precision control system. First, the physical characteristics of the impulse in momentum, such as motion and energy, were analyzed and formulated. Then, experimental response to a new pulse with two harmonic expansions was studied. The first harmonic is the main pulse to drive the arm, and the second harmonic has two functions： its first half helps the main pulse eliminate the dead zone, and its second half, a negative pulse, stops the arm motion quickly. Finally, an impulse feedback controller was developed. Comparison between simulation and experiments shows the effectiveness of the proposed controller.展开更多
Targeted stem cell delivery utilizing a magnetic actuation system is an emerging technology in stem cell engineering that efficiently targets stem cells in specific areas in vitro.However,integrating precise magnetic ...Targeted stem cell delivery utilizing a magnetic actuation system is an emerging technology in stem cell engineering that efficiently targets stem cells in specific areas in vitro.However,integrating precise magnetic control systems with selective neural differentiation has not yet been widely considered for building successful neural networks.Challenges arise in creating targeted functional neuronal networks,largely due to difficulties in simultaneously controlling the positions of stem cells and selectively stimulating their differentiation.These challenges often result in suboptimal differentiation rates and abnormalities in transplanted neural stem cells.In contrast,ultrasound stimulation has superior tissue penetration and focusing capability,and represents a promising noninvasive neural stimulation technique capable of modulating neural activity and promoting selective differentiation into neuronal stem cells.In this study,we introduce a method for targeted neural differentiation using localized ultrasonic stimulation with a piezoelectric micromachined ultrasound transducer(pMUT)array.Differentiation was assessed quantitatively by monitoring neurite outgrowth as the ultrasound intensity was increased.The neurite length of cells ultrasonically stimulated for 40 min was found to have increased,compared to the non-stimulated group(119.9±34.3μm vs.63.2±17.3μm,respectively).Targeted differentiation was confirmed by measuring neurite lengths,where selective ultrasound stimulation induced differentiation in cells that were precisely delivered via an electromagnetic system.Magnetic cell-based robots reaching the area of localized ultrasound stimulation were confirmed to have enhanced differentiation.This research demonstrated the potential of the combination of precise stem cell delivery with selective neural differentiation to establish functional neural networks.展开更多
This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semicon...This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semiconductor integrated circuits(ICs).Leadingedge semiconductor lithography has some of the most aggressive technology requirements,and has been a key driver in the 50-year history of semiconductor scaling.Introducing a new,disruptive capability into this arena is therefore a case study in a“highrisk-high-reward”opportunity.This article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry,novel research ideas being explored,and literature in nanoimprint lithography.The article then focuses on the J-FIL process,and the interdisciplinary nature of risk,involving nanoscale precision systems,mechanics,materials,material delivery systems,contamination control,and process engineering.Next,the article discusses the strategic decisions that were made in the early phases of the project including:(i)choosing a step and repeat process approach;(ii)identifying the first target IC market for J-FIL;(iii)defining the product scope and the appropriate collaborations to share the risk-reward landscape;and(iv)properly leveraging existing infrastructure,including minimizing disruption to the widely accepted practices in photolithography.Finally,the paper discusses the commercial J-FIL stepper system and associated infrastructure,and the resulting advances in the key lithographic process metrics such as critical dimension control,overlay,throughput,process defects,and electrical yield over the past 5 years.This article concludes with the current state of the art in J-FIL technology for IC fabrication,including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.展开更多
基金The Foundation of Sichuan Education Department (No.09ZC24)
文摘A friction model was established for impulse control design in a precision control system. First, the physical characteristics of the impulse in momentum, such as motion and energy, were analyzed and formulated. Then, experimental response to a new pulse with two harmonic expansions was studied. The first harmonic is the main pulse to drive the arm, and the second harmonic has two functions： its first half helps the main pulse eliminate the dead zone, and its second half, a negative pulse, stops the arm motion quickly. Finally, an impulse feedback controller was developed. Comparison between simulation and experiments shows the effectiveness of the proposed controller.
基金financially supported by the National Convergence Research of Scientific Challenges through the National Research Foundation of Korea(NRF)(no.2021M3F7A1082275)funded by the Ministry of Science and ICT.
文摘Targeted stem cell delivery utilizing a magnetic actuation system is an emerging technology in stem cell engineering that efficiently targets stem cells in specific areas in vitro.However,integrating precise magnetic control systems with selective neural differentiation has not yet been widely considered for building successful neural networks.Challenges arise in creating targeted functional neuronal networks,largely due to difficulties in simultaneously controlling the positions of stem cells and selectively stimulating their differentiation.These challenges often result in suboptimal differentiation rates and abnormalities in transplanted neural stem cells.In contrast,ultrasound stimulation has superior tissue penetration and focusing capability,and represents a promising noninvasive neural stimulation technique capable of modulating neural activity and promoting selective differentiation into neuronal stem cells.In this study,we introduce a method for targeted neural differentiation using localized ultrasonic stimulation with a piezoelectric micromachined ultrasound transducer(pMUT)array.Differentiation was assessed quantitatively by monitoring neurite outgrowth as the ultrasound intensity was increased.The neurite length of cells ultrasonically stimulated for 40 min was found to have increased,compared to the non-stimulated group(119.9±34.3μm vs.63.2±17.3μm,respectively).Targeted differentiation was confirmed by measuring neurite lengths,where selective ultrasound stimulation induced differentiation in cells that were precisely delivered via an electromagnetic system.Magnetic cell-based robots reaching the area of localized ultrasound stimulation were confirmed to have enhanced differentiation.This research demonstrated the potential of the combination of precise stem cell delivery with selective neural differentiation to establish functional neural networks.
基金This work was partially funded by DARPA Contract No.N66001-02-C-8011NIST Advanced Technology Program Contract No.70NANB4H3012+2 种基金US DoD Contract No.N66001-06-C-2003DARPA A2P Program administered by AFRL Contract No.FA8650-15-C-7542by the National Science Foundation under Cooperative Agreement No.EEC-1160494.
文摘This article discusses the transition of a form of nanoimprint lithography technology,known as Jet and Flash Imprint Lithography(J-FIL),from research to a commercial fabrication infrastructure for leading-edge semiconductor integrated circuits(ICs).Leadingedge semiconductor lithography has some of the most aggressive technology requirements,and has been a key driver in the 50-year history of semiconductor scaling.Introducing a new,disruptive capability into this arena is therefore a case study in a“highrisk-high-reward”opportunity.This article first discusses relevant literature in nanopatterning including advanced lithography options that have been explored by the IC fabrication industry,novel research ideas being explored,and literature in nanoimprint lithography.The article then focuses on the J-FIL process,and the interdisciplinary nature of risk,involving nanoscale precision systems,mechanics,materials,material delivery systems,contamination control,and process engineering.Next,the article discusses the strategic decisions that were made in the early phases of the project including:(i)choosing a step and repeat process approach;(ii)identifying the first target IC market for J-FIL;(iii)defining the product scope and the appropriate collaborations to share the risk-reward landscape;and(iv)properly leveraging existing infrastructure,including minimizing disruption to the widely accepted practices in photolithography.Finally,the paper discusses the commercial J-FIL stepper system and associated infrastructure,and the resulting advances in the key lithographic process metrics such as critical dimension control,overlay,throughput,process defects,and electrical yield over the past 5 years.This article concludes with the current state of the art in J-FIL technology for IC fabrication,including description of the high volume manufacturing stepper tools created for advanced memory manufacturing.
