Taking Sutong Bridge as the object investigated, the correctness of the geometry control method is verified by numerical simulation analysis. Taking the impact of geometric nonlinearity into account, the impacts of st...Taking Sutong Bridge as the object investigated, the correctness of the geometry control method is verified by numerical simulation analysis. Taking the impact of geometric nonlinearity into account, the impacts of structural geo- metric profile induced by temporary loads and temperature field during the construction procedure are investigated. The simulation results indicate that only the stage state of the structure during construction is affected. Satisfied outcome of construction control can be achieved based on ~eometrv control method.展开更多
Nerve guidance channels for peripheral nerve injury： Over the past decade, nerve guidance channels （NGCs） have emerged as a promising technology for regenerating gap injuries in peripheral nerves. Nerve gap injurie...Nerve guidance channels for peripheral nerve injury： Over the past decade, nerve guidance channels （NGCs） have emerged as a promising technology for regenerating gap injuries in peripheral nerves. Nerve gap injuries resulting from neurodegeneration and trauma, such as car accidents and battlefield wounds, affect hun- dreds of thousands of people annually. Motivated by suboptimal results obtained with the current gold standard of autologous grafting （i.e., autografts）, various commercially available NGCs composed of synthetic and biomaterials are now alternatively available （Jia et al., 2014; Jones et al., 2016）.展开更多
Precise control of a magnetically suspended double-gimbal control moment gyroscope （MSDGCMG） is of vital importance and challenge to the attitude positioning of spacecraft owing to its multivariable, nonlinear and s...Precise control of a magnetically suspended double-gimbal control moment gyroscope （MSDGCMG） is of vital importance and challenge to the attitude positioning of spacecraft owing to its multivariable, nonlinear and strong coupled properties. This paper proposes a novel linearization and decoupling method based on differential geometry theory and combines it with the internal model controller （IMC） to guarantee the system robustness to the external disturbance and parameter uncertainty. Furthermore, by introducing the dynamic compensation for the inner-gimbal rate-servo system and the magnetically suspended rotor （MSR） system only, we can eliminate the influence of the unmodeled dynamics to the decoupling control accuracy as well as save costs and inhibit noises effectively. The simulation results verify the nice decoupling and robustness performance of the system using the proposed method.展开更多
The Sutong Yangtze River Bridge(short as Sutong Bridge)is now the largest span cable-stayed bridge in the world.The construction of the superstructure of the middle bridge covered several stages including erection of ...The Sutong Yangtze River Bridge(short as Sutong Bridge)is now the largest span cable-stayed bridge in the world.The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span,assistant span and tower area,erection of standard girders and closure of the middle span.The big block girders were hoisted by a floating crane,and the standard girders were hoisted by a double crane system on the deck.The pushing assistant method was adopted for the middle span closure construction.Furthermore,key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically.An all-stage self-adaptive geometry control method was used in the construction process.By accurately controlling the unstressed dimensions and shape of all structural components in each step,and realization that the control system and the controlled system adapt to each other,the goal was to make control of the final line shape and inner force of the bridge structure achievable.Two solutions,including GPS based and total station based dynamic geometry monitoring systems,were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state.Finally,research on the wind-induced vibration of the superstructure during the construction period was executed.Buffeting response analysis to the longest single and double cantilever states were carried out.The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made,and corresponding wind resistance measures were suggested.The as-built geometric error and cable force error were controlled in a required design range,and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.展开更多
A new non-decoupling three-dimensional guidance law is proposed for bank-to-turn （BTT） missiles with the motion coupling problem. In this method, the different geometry is taken for theoretically modeling on B-IT mi...A new non-decoupling three-dimensional guidance law is proposed for bank-to-turn （BTT） missiles with the motion coupling problem. In this method, the different geometry is taken for theoretically modeling on B-IT missiles＇ motion within the threedimensional style without information loss, and meanwhile, Liegroup is utilized to describe the line-of-sight （LOS） azimuth when the terminal angular constraints are considered. Under these cir- cumstances, a guidance kinematics model is established based on differential geometry. Then, corresponding to no terminal angular constraint and terminal angular constraints, guidance laws are re- spectively designed by using proportional control and generalized proportional-derivative （PD） control in SO（3） group. Eventually, simulation results validate that this developed method can effectively avoid the complexity of pure Lie-group method and the information loss of the traditional decoupling method as well.展开更多
A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and t...A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.展开更多
Synthetic control of metal oxide nanocrystals with precise size and morphology is of great importance for promising optoelectronic applications due to their unique size-and shape-dependent optical/optoelectronic prope...Synthetic control of metal oxide nanocrystals with precise size and morphology is of great importance for promising optoelectronic applications due to their unique size-and shape-dependent optical/optoelectronic properties.Nevertheless,the understanding of the mechanism for size and morphology control of metal oxide nanocrystals are less studied.Here,we demonstrate that acetic acid,the byproduct of the initial chemical reaction of precursors,plays a dominant role in determining the morphology of indium oxide(In_(2)O_(3))nanocrystals by influencing the nucleation of the nanocrystals formation.Sufficient acetic acid would induce anisotropic growth,leading to the generation of nanoflowers,while limited existence of acetic acid results in sphere-shaped nanocrystals.Furthermore,the effects of geometries of In_(2)O_(3) nanocrystals on their plasmonic properties are studied.The resulting plasmonic In_(2)O_(3) nanocrystals show size-tunable plasmon resonance peaks in the near-infrared to mid-infrared regime and outstanding air/thermal stability.Our work shall give an in-depth understanding of the mechanism for geometry control of nanocrystals and offer more opportunities in potential optoelectronic and photothermal applications based on plasmonic metal oxide nanocrystals.展开更多
基金National Science and Technology Supporting Program of China ( No. 2006BAG04B03)
文摘Taking Sutong Bridge as the object investigated, the correctness of the geometry control method is verified by numerical simulation analysis. Taking the impact of geometric nonlinearity into account, the impacts of structural geo- metric profile induced by temporary loads and temperature field during the construction procedure are investigated. The simulation results indicate that only the stage state of the structure during construction is affected. Satisfied outcome of construction control can be achieved based on ~eometrv control method.
基金supported by the Maryland Stem Cell Research Fund(2013-MSCRFE-146-00)(to XJ)in part by the National Institute of Health(R01HL118084)(to XJ)
文摘Nerve guidance channels for peripheral nerve injury： Over the past decade, nerve guidance channels （NGCs） have emerged as a promising technology for regenerating gap injuries in peripheral nerves. Nerve gap injuries resulting from neurodegeneration and trauma, such as car accidents and battlefield wounds, affect hun- dreds of thousands of people annually. Motivated by suboptimal results obtained with the current gold standard of autologous grafting （i.e., autografts）, various commercially available NGCs composed of synthetic and biomaterials are now alternatively available （Jia et al., 2014; Jones et al., 2016）.
文摘Precise control of a magnetically suspended double-gimbal control moment gyroscope （MSDGCMG） is of vital importance and challenge to the attitude positioning of spacecraft owing to its multivariable, nonlinear and strong coupled properties. This paper proposes a novel linearization and decoupling method based on differential geometry theory and combines it with the internal model controller （IMC） to guarantee the system robustness to the external disturbance and parameter uncertainty. Furthermore, by introducing the dynamic compensation for the inner-gimbal rate-servo system and the magnetically suspended rotor （MSR） system only, we can eliminate the influence of the unmodeled dynamics to the decoupling control accuracy as well as save costs and inhibit noises effectively. The simulation results verify the nice decoupling and robustness performance of the system using the proposed method.
基金National Science and Technology Support Program of China(No.2006BAG04B03)
文摘The Sutong Yangtze River Bridge(short as Sutong Bridge)is now the largest span cable-stayed bridge in the world.The construction of the superstructure of the middle bridge covered several stages including erection of the big block girders for the side span,assistant span and tower area,erection of standard girders and closure of the middle span.The big block girders were hoisted by a floating crane,and the standard girders were hoisted by a double crane system on the deck.The pushing assistant method was adopted for the middle span closure construction.Furthermore,key technologies and innovative methods used in the processes of girder erection and cable assemblage in all stages were expatiated systematically.An all-stage self-adaptive geometry control method was used in the construction process.By accurately controlling the unstressed dimensions and shape of all structural components in each step,and realization that the control system and the controlled system adapt to each other,the goal was to make control of the final line shape and inner force of the bridge structure achievable.Two solutions,including GPS based and total station based dynamic geometry monitoring systems,were used to resolve the measure problem under the wide-range of wind-induced vibrations in the long cantilever state.Finally,research on the wind-induced vibration of the superstructure during the construction period was executed.Buffeting response analysis to the longest single and double cantilever states were carried out.The analysis and evaluation of wind resistance safety of the main girders under the longest single cantilever state was made,and corresponding wind resistance measures were suggested.The as-built geometric error and cable force error were controlled in a required design range,and this whole technological achievement can be a benchmark for construction of other large span cable-stayed bridges in the future.
基金supported by the National University of Defense Technology Innovation Support Project for Outstanding Graduate Student(B100303)
文摘A new non-decoupling three-dimensional guidance law is proposed for bank-to-turn （BTT） missiles with the motion coupling problem. In this method, the different geometry is taken for theoretically modeling on B-IT missiles＇ motion within the threedimensional style without information loss, and meanwhile, Liegroup is utilized to describe the line-of-sight （LOS） azimuth when the terminal angular constraints are considered. Under these cir- cumstances, a guidance kinematics model is established based on differential geometry. Then, corresponding to no terminal angular constraint and terminal angular constraints, guidance laws are re- spectively designed by using proportional control and generalized proportional-derivative （PD） control in SO（3） group. Eventually, simulation results validate that this developed method can effectively avoid the complexity of pure Lie-group method and the information loss of the traditional decoupling method as well.
基金Supported by Diesel Engine Development Program of MIIT(DEDP-1004)Natural Science Foundation of BIT(3030012211428)
文摘A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.
基金financially supported by the National Natural Science Foundation of China (22005267 and 22105011)the Basic Public Research Program of Zhejiang Province (LGF22B010004 and LY23B010001)+3 种基金the National Key Technologies R&D Program of China (2022YFA1207000)the Research Funds of Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences (A05006C019001 and 2024HIAS-Y008)Hangzhou Science and Technology Bureau of Zhejiang Province (TD2020002)Department of Science and Technology of Zhejiang Province (2024C01192)。
文摘Synthetic control of metal oxide nanocrystals with precise size and morphology is of great importance for promising optoelectronic applications due to their unique size-and shape-dependent optical/optoelectronic properties.Nevertheless,the understanding of the mechanism for size and morphology control of metal oxide nanocrystals are less studied.Here,we demonstrate that acetic acid,the byproduct of the initial chemical reaction of precursors,plays a dominant role in determining the morphology of indium oxide(In_(2)O_(3))nanocrystals by influencing the nucleation of the nanocrystals formation.Sufficient acetic acid would induce anisotropic growth,leading to the generation of nanoflowers,while limited existence of acetic acid results in sphere-shaped nanocrystals.Furthermore,the effects of geometries of In_(2)O_(3) nanocrystals on their plasmonic properties are studied.The resulting plasmonic In_(2)O_(3) nanocrystals show size-tunable plasmon resonance peaks in the near-infrared to mid-infrared regime and outstanding air/thermal stability.Our work shall give an in-depth understanding of the mechanism for geometry control of nanocrystals and offer more opportunities in potential optoelectronic and photothermal applications based on plasmonic metal oxide nanocrystals.
