The 3D characteristic diagram of acoustically induced surface vibration was employed to study the influence of different buried landmines on the acoustic detection signal. By using the vehicular experimental system fo...The 3D characteristic diagram of acoustically induced surface vibration was employed to study the influence of different buried landmines on the acoustic detection signal. By using the vehicular experimental system for acoustic landmine detection and the method of scanning detection, the 3D characteristic diagrams of surface vibration were measured when different objects were buried underground, including big plastic landmine, small plastic landmine, big metal landmine and bricks. The results show that, under the given conditions, the surface vibration amplitudes of big plastic landmine, big metal landmine, small plastic landmine and bricks decrease in turn. The 3D characteristic diagrams of surface vibration can be used to further identify the locations of buried landmines.展开更多
The insulating ceramics were processed with sinking and wire cut electrical discharge machining(EDM). The new technology was named as the assisting electrode method. In the machining, the electrical conductive materia...The insulating ceramics were processed with sinking and wire cut electrical discharge machining(EDM). The new technology was named as the assisting electrode method. In the machining, the electrical conductive material was adhered on the surface of insulating workpiece as the starting point of electrical discharge. As the processing operated in oil, the electrical conductive product composed of decomposition carbon element from working oil adhered on the workpiece during discharge. The discharges generated continuously with the formation of the electrical conductive layer. So, the insulating ceramics turn to the machinable material by EDM. We introduced the mechanism and the application of the machining of insulating ceramics such as Si3N4 and ZrO2.展开更多
The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine...The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine detection and the characteristics of low-frequency acoustics, the “soil-mine” system could be equivalent to a damping “mass-spring” resonance model with a lumped parameter analysis method. The dynamic simulation software, Adams, is adopted to analyze the lumped parameter system model numerically. The simulated resonance frequency and anti-resonance frequency are 151 Hz and 512 Hz respectively, basically in agreement with the published resonance frequency of 155 Hz and anti-resonance frequency of 513 Hz, which were measured in the experiment. Therefore, the technique of numerical simulation is validated to have the potential for analyzing the acoustic mine detection model quantitatively. The influences of the soil and mine parameters on the resonance characteristics of the soil–mine system could be investigated by changing the parameter setup in a flexible manner.展开更多
We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram...We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.展开更多
For the aim of synthesis of the carbon-iodine compound, the preparation of iodin e-included carbon using RF plasma CVD was studied. Iodine-included carbon was sy nthesized on Si substrate using ICP type RF plasma CVD ...For the aim of synthesis of the carbon-iodine compound, the preparation of iodin e-included carbon using RF plasma CVD was studied. Iodine-included carbon was sy nthesized on Si substrate using ICP type RF plasma CVD apparatus. C2H5OH and I2 dissolved C2H5OH was used as reactant gases. As a result, surface morphologies o f Iodine included carbon films showed flat surfaces for each samples. On the str ucture of films estimated by Raman spectroscopy, amorphous carbon was recognized . And I2 peaks were observed in XPS spectra. As a result of friction test, frict ion coefficient of the sample growth with C2H5OH showed about 0.45. On the other hand, that of the sample with I2-C2H5OH showed about 0.3 and decrease of fricti on coefficient was recognized. Iodine inclusion for carbon materials can be achi eved by RF plasma CVD using an I2-C2H5OH reactant. The coefficient of iodine-inc luded carbon showed lower than of without iodine展开更多
In order to verify the properties of the light propagating through a gradient-index (GRIN) fibre probe for optical coherence tomography (OCT), numerical simulation using the optical software GLAD is carried out. F...In order to verify the properties of the light propagating through a gradient-index (GRIN) fibre probe for optical coherence tomography (OCT), numerical simulation using the optical software GLAD is carried out. Firstly, the model of the GRIN fibre probe is presented, which is consisted of a single mode fibre (SMF), a no-core fibre (NCF), a GRIN fibre lens and an air path. Then, the software GLAD is adopted to numerically investigate how the lengths of the NCF and the GRIN fibre lens influence the performance of the Gaussian beam focusing through the GRIN fibre probe. The simulation results are well consistent with the experimental ones, showing that the GLAD based numerical simulation technique is an intuitive and effective tool for the verification of the properties of the light propagation. In this paper, we find that on the conditions of a constant GRIN fibre lens length of 0.1 mm and an NCF length of 0.36 mm, the working distance of the probe will be 0.75 mm and the focus spot size is 32 μm.展开更多
The processed surface contour shape is extracted with the finite element simulation software.The difference value of contour shape change is used as the parameters of balancing surface roughness to construct finite el...The processed surface contour shape is extracted with the finite element simulation software.The difference value of contour shape change is used as the parameters of balancing surface roughness to construct finite element model of supersonic vibration milling in cutting stability domain.The surface roughness trial scheme is designed in the orthogonal test design method to analyze the surface roughness test result in the response surface methodology.The surface roughness prediction model is established and optimized.Finally,the surface roughness finite element simulation prediction model is verified by experiments.The research results show that,compared with the experiment results,the error range of the finite element simulation model is 27.5%–30.9%,and the error range of the empirical model obtained by the response surface method is between 4.4%and 12.3%.So,the model in this paper is accurate and will provide the theoretical basis for the optimization study of the auxiliary milling process of supersonic vibration.展开更多
Wetting is one of the omnipresent phenomena governed via natural laws. Moreover, surface wettability at non-ambient temperature especially at high temperature (30°C to 90°C) is of great importance in many in...Wetting is one of the omnipresent phenomena governed via natural laws. Moreover, surface wettability at non-ambient temperature especially at high temperature (30°C to 90°C) is of great importance in many industrial processes. In this study, Si wafers with various structures were fabricated to investigate wettability at different temperatures. Three shapes with micro-pillar structured surfaces were designed and fabricated. Pillar-structured surfaces were fabricated by photolithography and ICP etching. The temperature-dependent wettability of single-phase regime droplets was characterized using contact angle measurements. The wetting behavior of a water droplet was observed.展开更多
In order to control cutting force and its direction i n milling operation, a new milling head was developed. The head has two milling cutters, which are connected by a pair of gears and rotate in opposite direction re...In order to control cutting force and its direction i n milling operation, a new milling head was developed. The head has two milling cutters, which are connected by a pair of gears and rotate in opposite direction respectively. Both up-cut and down-cut can be carried out simultaneously by t hese milling cutters. The each depth of cut, the ratio of up/down cutting depth , by these cutters can be also selected. The cutting force characteristics were experimentally discussed by changing the ratio. The cutting force and its locus can be also changed by the selection of the ratio of up/down cutting depth. For practical usage of the head the analytical prediction method of the cutting forc e characteristics under selected cutting condition was proposed based on the ene rgy approach method proposed, in which both of cutting force characteristics of a single milling cutter and the combined milling cutter under a selected up/dow n cutting depth ratio were analytically estimated based on the two dimensional c utting data. It was experimentally shown that in NC milling machine the cutting force locus was controlled in pre-determined direction under various tool paths .展开更多
The marine area of Japan, including territorial waters and the exclusive economic zone, is the sixth largest in the world at about 4,470,000 km2. Therefore, it is becoming necessary to establish appropriate means of t...The marine area of Japan, including territorial waters and the exclusive economic zone, is the sixth largest in the world at about 4,470,000 km2. Therefore, it is becoming necessary to establish appropriate means of transportation other than ships in order to utilize the area efficiently. In this respect, ultra-light seaplanes are attracting attention from the viewpoint of protecting the natural environment. Accordingly, JRPS (Japan Reinforced Plastics Society) is currently developing FRP (fiber-reinforced plastic) floats for such planes. In this study, we conducted simulations of seaplane behavior during alighting by using the smoothed particle hydrodynamics method, which is one of the functions in the PAM-CRASH solver, and we present the observed trend in the vertical acceleration of the floats as a first step toward deriving the impact force from analytical data.展开更多
This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence signals.The interfacial conditions between the tool and the workpiece in mechanical machining are imp...This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence signals.The interfacial conditions between the tool and the workpiece in mechanical machining are important for understanding these phenomena and mechanisms.In this study,indentation tests with transparent tools were used to observe interfaces;however,it was challenging to obtain the signal from a thin fluorescent liquid film on smooth and steeply inclined surfaces.Therefore,fluorescence-based measurement,such as laser-induced fluorescence,was employed.To measure the absolute thickness of the thin fluorescent film,calibration of the measurement system is necessary.Therefore,a theoretical model was proposed considering the multiple reflections of excitation light and fluorescence at the inclined surface between the indenter and workpiece.By measuring the profile of the surface topography of the indented workpiece and comparing the results with those measured by a surface profiler,the validity of the proposed calibration method and the performance of this measurement system were demonstrated.The measured surface profiles,including scratches of 2–4μm,were in good agreement,demonstrating the validity of the proposed method.展开更多
Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to...Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active sites.In this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and OER.The Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M KOH.Experimental results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption energy.For evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,respectively.The present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.展开更多
Configuration design is an essential, creative and decision-making step m parallel manipulator design process, in which modeling and assembly are iterative and trivial. Combined approach with automatic parametric mode...Configuration design is an essential, creative and decision-making step m parallel manipulator design process, in which modeling and assembly are iterative and trivial. Combined approach with automatic parametric modeling and automatic assembly is proposed for parallel manipulator configuration design. The design process and key techniques, such as configuration design, configuration verification, poses calculation of all parts in parallel manipulator, virtual assembly and etc., are discussed and demonstrated by an example. A software package is developed for parallel manipulator configuration design based on the proposed method with Visual C++ and UG/OPEN on Unigraphics.展开更多
Overlay(OVL)for patterns placed at two different layers during microchip production is a key parameter that controls the manufacturing process.The tolerance of OVL metrology for the latest microchip needs to be at nan...Overlay(OVL)for patterns placed at two different layers during microchip production is a key parameter that controls the manufacturing process.The tolerance of OVL metrology for the latest microchip needs to be at nanometer scale.This paper discusses the influence on the accuracy and sensitivity of diffraction-based overlay(DBO)after developing inspection and after etching inspection by the asymmetrical deformation of the OVL mark induced by chemical mechanical polishing or etching.We show that the accuracy and sensitivity of DBO metrology can be significantly improved by matching the measuring light wavelength to the thickness between layers and by collecting high-order diffraction signals,promising a solution for future OVL metrology equipment.展开更多
Since small unmanned helicopter flight attitude control process has strong time-varying characteristics and there are random disturbances,the conventional control methods with unchanged parameters are often unworkable...Since small unmanned helicopter flight attitude control process has strong time-varying characteristics and there are random disturbances,the conventional control methods with unchanged parameters are often unworkable.An on-line adaptive fuzzy control system(AFCS)was designed,in a way that does not depend on a process model of the plant or its approximation in the form of a Jacobian matrix.Neither is it necessary to know the desired response at each instant of time.AFCS implement a simultaneous on-line tuning of fuzzy rules and output scale of fuzzy control system.The two cascade controller design with an inner(attitude controller)and outer controller(navigation controller)of the small unmanned helicopter was proposed.At last,an attitude controller based on AFCS was implemented.The flight experiment showed that the proposed fuzzy logic controller provides quicker response,smaller overshoot,higher precision,robustness and adaptive ability.It satisfies the needs of autonomous flight.展开更多
A new controllable laser beam shaping technique is demonstrated, where a magnetic fluid-based liquid deformable mirror is proposed to redistribute the laser phase profile and thus change the propagation property of th...A new controllable laser beam shaping technique is demonstrated, where a magnetic fluid-based liquid deformable mirror is proposed to redistribute the laser phase profile and thus change the propagation property of the beam. The mirror is driven by an inner miniature actuator array along with a large outer actuator. The inner actuator array is used for deforming the magnetic fluid surface, while the outer actuator is used to linearize the fluid surface response and amplify the magnitude of the deflection. In comparison to other laser beam shaping techniques, this technique offers the advantages such as simplicity, low cost, large shape deformation, and high adaptability. Based on a fabricated prototype of the liquid deformable mirror, an experimental AO system was set up to produce a desired conical surface shape that shaped the incident beam into a Bessel beam. The experimental results show the effectiveness of the proposed technique for laser beam shaping.展开更多
The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functi...The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functional theory(DFT).We identify several types of structural defects and find that most have a local character limited to a single CDW site,with a single exception which effectively behaves as a dopant,leading to band-bending and affecting multiple neighboring sites.While only one type of defect can be observed by STM topographic imaging,all defects are easily resolved in STS mapping.Our results indicate modulation of the Mott band gap commensurate with the CDW and breaking of the three-fold symmetry of electronic states.DFT calculations(with included Coulomb interactions)are used to investigate the electronic structure,focusing on both sulfur vacancy and oxygen-sulfur substitution.The sulfur vacancy system,characterized with a metallic behavior,is identified as the origin of one of the experimentally observed defects.Additionally,the effect of oxidation of 1T-TaS_(2)depends on the substitution site,leading to the heterogeneity of electronic properties.展开更多
Organic soft actuators are of special interest in many fields including intravascular neurosurgery. Ion conductive polymer film (ICPF) actuators have been one of the strong candidates. The ICPF investigated here was...Organic soft actuators are of special interest in many fields including intravascular neurosurgery. Ion conductive polymer film (ICPF) actuators have been one of the strong candidates. The ICPF investigated here was a cation-exchange membrane (Nation 117, Du Pont). When a voltage is given between the metal eIectrodes of an ICPF actuator, the ICPF actuator bends in the water due to the motion of Li+ cations with associated water. In order to increase the freedom of the deformation of the ICPF actuator, structures of independent electrode pairs were proposed. The electrodes were selectively deposited by non-electrokvzed plating including the Pt [(NH3)6]^4+ deposition process in a [Pt(NH3)6]Cl4 solution and the reduction process in a NaBH4 solution. Here, an elastomer adhesive tape with a fine electrode patterns was used performances were reported in detail. as a mask. The actuators processing conditions and their actuator展开更多
The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differentia...The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differential kinematics and mobility are studied. The minimal structure for realizing the task motion of the object is obtained, and the conditions for dexterous manipulation are presented. Finally, some rolling manipulations are used as examples to demonstrate the applicability of approach proposed.展开更多
基金Supported by the National Natural Science Foundation of China(No.61575119)Science and Technology on Near-Surface Detection Laboratory(No.TCGZ2015A005)State Key Laboratory of Precision Measuring Technology and Instruments(PIL1402)
文摘The 3D characteristic diagram of acoustically induced surface vibration was employed to study the influence of different buried landmines on the acoustic detection signal. By using the vehicular experimental system for acoustic landmine detection and the method of scanning detection, the 3D characteristic diagrams of surface vibration were measured when different objects were buried underground, including big plastic landmine, small plastic landmine, big metal landmine and bricks. The results show that, under the given conditions, the surface vibration amplitudes of big plastic landmine, big metal landmine, small plastic landmine and bricks decrease in turn. The 3D characteristic diagrams of surface vibration can be used to further identify the locations of buried landmines.
文摘The insulating ceramics were processed with sinking and wire cut electrical discharge machining(EDM). The new technology was named as the assisting electrode method. In the machining, the electrical conductive material was adhered on the surface of insulating workpiece as the starting point of electrical discharge. As the processing operated in oil, the electrical conductive product composed of decomposition carbon element from working oil adhered on the workpiece during discharge. The discharges generated continuously with the formation of the electrical conductive layer. So, the insulating ceramics turn to the machinable material by EDM. We introduced the mechanism and the application of the machining of insulating ceramics such as Si3N4 and ZrO2.
基金Project supported,in part,by the National Natural Science Foundation of China(Grant No.41104065)the"Chen Guang"Program of Shanghai Municipal Ed-ucation Commission and Shanghai Education Development Foundation,China(Grant No.12CG047)+1 种基金the Scientific Research Innovation Program of Shanghai Municipal Education Commission,China(Grant No.13YZ022)the State Key Laboratory of Precision Measuring Technology and Instruments,China
文摘The method of numerical analysis is employed to study the resonance mechanism of the lumped parameter system model for acoustic mine detection. Based on the basic principle of the acoustic resonance technique for mine detection and the characteristics of low-frequency acoustics, the “soil-mine” system could be equivalent to a damping “mass-spring” resonance model with a lumped parameter analysis method. The dynamic simulation software, Adams, is adopted to analyze the lumped parameter system model numerically. The simulated resonance frequency and anti-resonance frequency are 151 Hz and 512 Hz respectively, basically in agreement with the published resonance frequency of 155 Hz and anti-resonance frequency of 513 Hz, which were measured in the experiment. Therefore, the technique of numerical simulation is validated to have the potential for analyzing the acoustic mine detection model quantitatively. The influences of the soil and mine parameters on the resonance characteristics of the soil–mine system could be investigated by changing the parameter setup in a flexible manner.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474194,11004037,and 61101176)the Natural Science Foundation of Shanghai,China(Grant No.14ZR1415500)
文摘We present holographic storage of three-dimensional(3D) images and data in a photopolymer film without any applied electric field.Its absorption and diffraction efficiency are measured,and reflective analog hologram of real object and image of digital information are recorded in the films.The photopolymer is compared with polymer dispersed liquid crystals as holographic materials.Besides holographic diffraction efficiency of the former is little lower than that of the latter,this work demonstrates that the photopolymer is more suitable for analog hologram and big data permanent storage because of its high definition and no need of high voltage electric field.Therefore,our study proposes a potential holographic storage material to apply in large size static 3D holographic displays,including analog hologram displays,digital hologram prints,and holographic disks.
文摘For the aim of synthesis of the carbon-iodine compound, the preparation of iodin e-included carbon using RF plasma CVD was studied. Iodine-included carbon was sy nthesized on Si substrate using ICP type RF plasma CVD apparatus. C2H5OH and I2 dissolved C2H5OH was used as reactant gases. As a result, surface morphologies o f Iodine included carbon films showed flat surfaces for each samples. On the str ucture of films estimated by Raman spectroscopy, amorphous carbon was recognized . And I2 peaks were observed in XPS spectra. As a result of friction test, frict ion coefficient of the sample growth with C2H5OH showed about 0.45. On the other hand, that of the sample with I2-C2H5OH showed about 0.3 and decrease of fricti on coefficient was recognized. Iodine inclusion for carbon materials can be achi eved by RF plasma CVD using an I2-C2H5OH reactant. The coefficient of iodine-inc luded carbon showed lower than of without iodine
基金supported by the International Cooperation Project of Shanghai Science and Technology Committee,China(Grant No.09530708700)
文摘In order to verify the properties of the light propagating through a gradient-index (GRIN) fibre probe for optical coherence tomography (OCT), numerical simulation using the optical software GLAD is carried out. Firstly, the model of the GRIN fibre probe is presented, which is consisted of a single mode fibre (SMF), a no-core fibre (NCF), a GRIN fibre lens and an air path. Then, the software GLAD is adopted to numerically investigate how the lengths of the NCF and the GRIN fibre lens influence the performance of the Gaussian beam focusing through the GRIN fibre probe. The simulation results are well consistent with the experimental ones, showing that the GLAD based numerical simulation technique is an intuitive and effective tool for the verification of the properties of the light propagation. In this paper, we find that on the conditions of a constant GRIN fibre lens length of 0.1 mm and an NCF length of 0.36 mm, the working distance of the probe will be 0.75 mm and the focus spot size is 32 μm.
基金National Natural Science Foundation of China(Grant No.52175393).
文摘The processed surface contour shape is extracted with the finite element simulation software.The difference value of contour shape change is used as the parameters of balancing surface roughness to construct finite element model of supersonic vibration milling in cutting stability domain.The surface roughness trial scheme is designed in the orthogonal test design method to analyze the surface roughness test result in the response surface methodology.The surface roughness prediction model is established and optimized.Finally,the surface roughness finite element simulation prediction model is verified by experiments.The research results show that,compared with the experiment results,the error range of the finite element simulation model is 27.5%–30.9%,and the error range of the empirical model obtained by the response surface method is between 4.4%and 12.3%.So,the model in this paper is accurate and will provide the theoretical basis for the optimization study of the auxiliary milling process of supersonic vibration.
文摘Wetting is one of the omnipresent phenomena governed via natural laws. Moreover, surface wettability at non-ambient temperature especially at high temperature (30°C to 90°C) is of great importance in many industrial processes. In this study, Si wafers with various structures were fabricated to investigate wettability at different temperatures. Three shapes with micro-pillar structured surfaces were designed and fabricated. Pillar-structured surfaces were fabricated by photolithography and ICP etching. The temperature-dependent wettability of single-phase regime droplets was characterized using contact angle measurements. The wetting behavior of a water droplet was observed.
文摘In order to control cutting force and its direction i n milling operation, a new milling head was developed. The head has two milling cutters, which are connected by a pair of gears and rotate in opposite direction respectively. Both up-cut and down-cut can be carried out simultaneously by t hese milling cutters. The each depth of cut, the ratio of up/down cutting depth , by these cutters can be also selected. The cutting force characteristics were experimentally discussed by changing the ratio. The cutting force and its locus can be also changed by the selection of the ratio of up/down cutting depth. For practical usage of the head the analytical prediction method of the cutting forc e characteristics under selected cutting condition was proposed based on the ene rgy approach method proposed, in which both of cutting force characteristics of a single milling cutter and the combined milling cutter under a selected up/dow n cutting depth ratio were analytically estimated based on the two dimensional c utting data. It was experimentally shown that in NC milling machine the cutting force locus was controlled in pre-determined direction under various tool paths .
文摘The marine area of Japan, including territorial waters and the exclusive economic zone, is the sixth largest in the world at about 4,470,000 km2. Therefore, it is becoming necessary to establish appropriate means of transportation other than ships in order to utilize the area efficiently. In this respect, ultra-light seaplanes are attracting attention from the viewpoint of protecting the natural environment. Accordingly, JRPS (Japan Reinforced Plastics Society) is currently developing FRP (fiber-reinforced plastic) floats for such planes. In this study, we conducted simulations of seaplane behavior during alighting by using the smoothed particle hydrodynamics method, which is one of the functions in the PAM-CRASH solver, and we present the observed trend in the vertical acceleration of the floats as a first step toward deriving the impact force from analytical data.
基金would like to thank JSPS KAKENHI(No.23H01313)Machine Tool Engineering Foundation(No.RU-18),The Die and Mould Technology Promotion Foundation and The SATOMI Scholarship Foundation to provide financial support to this research.
文摘This study proposes a model for the measurement of microscale liquid film thickness distribution using fluorescence signals.The interfacial conditions between the tool and the workpiece in mechanical machining are important for understanding these phenomena and mechanisms.In this study,indentation tests with transparent tools were used to observe interfaces;however,it was challenging to obtain the signal from a thin fluorescent liquid film on smooth and steeply inclined surfaces.Therefore,fluorescence-based measurement,such as laser-induced fluorescence,was employed.To measure the absolute thickness of the thin fluorescent film,calibration of the measurement system is necessary.Therefore,a theoretical model was proposed considering the multiple reflections of excitation light and fluorescence at the inclined surface between the indenter and workpiece.By measuring the profile of the surface topography of the indented workpiece and comparing the results with those measured by a surface profiler,the validity of the proposed calibration method and the performance of this measurement system were demonstrated.The measured surface profiles,including scratches of 2–4μm,were in good agreement,demonstrating the validity of the proposed method.
基金supported by the Regional Leading Research Center Program(2019R1A5A8080326)Basic Science Research Program(2020R1F1A1075921)BRL Program(2020R1A4A1018259)through the National Research Foundation(NRF)funded by the Ministry of Science and ICT of Republic of Korea.
文摘Two-dimensional metal dichalcogenides have been evidenced as potential electrocatalysts for hydrogen evolution reaction(HER);however,their application is limited by a poor oxygen evolution reaction(OER)activity due to insufficient number/types of multi-integrated active sites.In this study,we report a novel bifunctional catalyst developed by simultaneous engineering of single nickel atoms(Ni_(SA)) and nickel phosphate clusters(Ni_(Pi)) to synergistically trigger surface-functionalized MoS_(2) nanosheets(NSs)resulting in high reactivities for both HER and OER.The Ni_(SA)-Ni_(Pi)/MoS_(2)NSs material exhibits a fairly Pt-like HER behavior with an overpotential of 94.0 mV and a small OER overpotential of 314.0 mV to reach 10 mA cm^(-2) in freshwater containing 1.0 M KOH.Experimental results of the catalyst are well supported by theoretical study,which reveals the significant modulation of electronic structure and enrichment of electroactive site number/types with their reasonably adjusted free adsorption energy.For evaluating practicability,the Ni_(SA)-Ni_(Pi)/MoS_(2)NSs-based electrolyzer delivers effective operation voltage of 1.62,1.52,and 1.66 V at 10 mA cm^(-2) and superior long-term stability as compared to Pt/C//RuO_(2) system in freshwater,mimic seawater,and natural seawater,respectively.The present study indicates that the catalyst is a promising candidate for the practical production of green hydrogen via water electrolysis.
文摘Configuration design is an essential, creative and decision-making step m parallel manipulator design process, in which modeling and assembly are iterative and trivial. Combined approach with automatic parametric modeling and automatic assembly is proposed for parallel manipulator configuration design. The design process and key techniques, such as configuration design, configuration verification, poses calculation of all parts in parallel manipulator, virtual assembly and etc., are discussed and demonstrated by an example. A software package is developed for parallel manipulator configuration design based on the proposed method with Visual C++ and UG/OPEN on Unigraphics.
基金supported by the Science and Technology Commission of Shanghai Municipality(No.22DZ1100300)。
文摘Overlay(OVL)for patterns placed at two different layers during microchip production is a key parameter that controls the manufacturing process.The tolerance of OVL metrology for the latest microchip needs to be at nanometer scale.This paper discusses the influence on the accuracy and sensitivity of diffraction-based overlay(DBO)after developing inspection and after etching inspection by the asymmetrical deformation of the OVL mark induced by chemical mechanical polishing or etching.We show that the accuracy and sensitivity of DBO metrology can be significantly improved by matching the measuring light wavelength to the thickness between layers and by collecting high-order diffraction signals,promising a solution for future OVL metrology equipment.
基金sponsored by The National High-tech Research and Development Program(Project No.2007AA041503 and 2007AA404260)the Research Program of Shanghai Science and Technology Committee (Project No.07dz05813)State Leading Academic Discipline,Shanghai Leading Aca-demic Discipline
文摘Since small unmanned helicopter flight attitude control process has strong time-varying characteristics and there are random disturbances,the conventional control methods with unchanged parameters are often unworkable.An on-line adaptive fuzzy control system(AFCS)was designed,in a way that does not depend on a process model of the plant or its approximation in the form of a Jacobian matrix.Neither is it necessary to know the desired response at each instant of time.AFCS implement a simultaneous on-line tuning of fuzzy rules and output scale of fuzzy control system.The two cascade controller design with an inner(attitude controller)and outer controller(navigation controller)of the small unmanned helicopter was proposed.At last,an attitude controller based on AFCS was implemented.The flight experiment showed that the proposed fuzzy logic controller provides quicker response,smaller overshoot,higher precision,robustness and adaptive ability.It satisfies the needs of autonomous flight.
基金Project supported by the National Natural Science Foundation of China(Grant No.51675321)Shanghai Municipal Natural Science Foundation,China(Grant No.15ZR1415800)the Innovation Program of Shanghai Municipal Education Commission,China(Grant No.14ZZ092)
文摘A new controllable laser beam shaping technique is demonstrated, where a magnetic fluid-based liquid deformable mirror is proposed to redistribute the laser phase profile and thus change the propagation property of the beam. The mirror is driven by an inner miniature actuator array along with a large outer actuator. The inner actuator array is used for deforming the magnetic fluid surface, while the outer actuator is used to linearize the fluid surface response and amplify the magnitude of the deflection. In comparison to other laser beam shaping techniques, this technique offers the advantages such as simplicity, low cost, large shape deformation, and high adaptability. Based on a fabricated prototype of the liquid deformable mirror, an experimental AO system was set up to produce a desired conical surface shape that shaped the incident beam into a Bessel beam. The experimental results show the effectiveness of the proposed technique for laser beam shaping.
基金supported by the National Science Centre,Poland under grants 2015/19/B/ST3/03142 and 2019/32/T/ST3/00487M.L.S.thanks for University of Lodz support under IDUB 6/JRR/2021 project.T.-C.C acknowledges support of the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Division of Materials Science and Engineering,under Grant No.DE-FG02-07ER46383+4 种基金M.G.acknowledges financial support provided by Slovak Research and Development Agency provided under Contract No.APVV-SKCZ-RD-21-0114by the Ministry of Education,Science,Research and Sport of the Slovak Republic provided under Grant No.VEGA 1/0105/20Slovak Academy of Sciences project IMPULZ IM-2021-42project FLAG ERA JTC 20212DSOTECHAuthor acknowledges the provision of the Polish Ministry of Education and Science project(Support for research and development with the use of research infrastructure of the National Synchrotron Radiation Centre SOLARIS”under contract nr 1/SOL/2021/2).
文摘The influence of intrinsic defects of 1T-TaS_(2)on charge density waves(CDWs)is studied using scanning tunneling microscopy and spectroscopy(STM,STS),angle-resolved photoelectron spectroscopy(ARPES),and density functional theory(DFT).We identify several types of structural defects and find that most have a local character limited to a single CDW site,with a single exception which effectively behaves as a dopant,leading to band-bending and affecting multiple neighboring sites.While only one type of defect can be observed by STM topographic imaging,all defects are easily resolved in STS mapping.Our results indicate modulation of the Mott band gap commensurate with the CDW and breaking of the three-fold symmetry of electronic states.DFT calculations(with included Coulomb interactions)are used to investigate the electronic structure,focusing on both sulfur vacancy and oxygen-sulfur substitution.The sulfur vacancy system,characterized with a metallic behavior,is identified as the origin of one of the experimentally observed defects.Additionally,the effect of oxidation of 1T-TaS_(2)depends on the substitution site,leading to the heterogeneity of electronic properties.
文摘Organic soft actuators are of special interest in many fields including intravascular neurosurgery. Ion conductive polymer film (ICPF) actuators have been one of the strong candidates. The ICPF investigated here was a cation-exchange membrane (Nation 117, Du Pont). When a voltage is given between the metal eIectrodes of an ICPF actuator, the ICPF actuator bends in the water due to the motion of Li+ cations with associated water. In order to increase the freedom of the deformation of the ICPF actuator, structures of independent electrode pairs were proposed. The electrodes were selectively deposited by non-electrokvzed plating including the Pt [(NH3)6]^4+ deposition process in a [Pt(NH3)6]Cl4 solution and the reduction process in a NaBH4 solution. Here, an elastomer adhesive tape with a fine electrode patterns was used performances were reported in detail. as a mask. The actuators processing conditions and their actuator
基金This project is supported by Scientific Research Foundation for ReturnedOverseas Chinese Scholars, Education Ministry of China and ProvincialNatural Science Foundation of Shanxi, China (No.2000C37).
文摘The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differential kinematics and mobility are studied. The minimal structure for realizing the task motion of the object is obtained, and the conditions for dexterous manipulation are presented. Finally, some rolling manipulations are used as examples to demonstrate the applicability of approach proposed.