To explore hostile extraterrestrial landforms and construct an engineering prototype,this paper presents the task-oriented topology system synthesis of reconfigurable legged mobile lander(ReLML)with three operation mo...To explore hostile extraterrestrial landforms and construct an engineering prototype,this paper presents the task-oriented topology system synthesis of reconfigurable legged mobile lander(ReLML)with three operation modes from adjusting,landing,to roving.Compared with our preceding works,the adjusting mode with three rotations(3R)provides a totally novel exploration approach to geometrically matching and securely arriving at complex terrains dangerous to visit currently;the landing mode is redefined by two rotations one translation(2R1T),identical with the tried-and-tested Apollo and Chang'E landers to enhance survivability via reasonable touchdown buffering motion;roving mode also utilizes 2R1T motion for good motion and force properties.The reconfigurable mechanism theory is first brought into synthesizing legged mobile lander integrating active and passive metamorphoses,composed of two types of metamorphic joints and metamorphic execution and transmission mechanisms.To reveal metamorphic principles with multiple finite motions,the finite screw theory is developed to present the procedure from unified mathematical representation,modes and source phase derivations,metamorphic joint and limb design,to final structure assembly.To identify the prototype topology,the 3D optimal selection matrix method is proposed considering three operation modes,five evaluation criteria,and two topological subsystems.Finally,simulation verifies the whole task implementation process to ensure the reasonability of design.展开更多
When Kant discusses the comprehensive role of transcendental imagination,he mentions the role of an empirical synthesis,which is the basis of perceptual activity,but if it is based on empirical synthesis then the cont...When Kant discusses the comprehensive role of transcendental imagination,he mentions the role of an empirical synthesis,which is the basis of perceptual activity,but if it is based on empirical synthesis then the contradiction of a priori comprehensive ability and empirical synthesis has occurred,and the relationship between active synthesis and passive synthesis of consciousness has now become a problem that must be solved.The description of the association idea has already incorporated the passive synthesis component,which actually provides a solution to this contradiction.展开更多
A series of boron- and phosphorus-doped silicon wafers are used to prepare a series of doped silicon nanocrystals （nc-Si） by high-energy ball milling with carboxylic acid-terminated surface. The sizes of the nc-Si s...A series of boron- and phosphorus-doped silicon wafers are used to prepare a series of doped silicon nanocrystals （nc-Si） by high-energy ball milling with carboxylic acid-terminated surface. The sizes of the nc-Si samples are demonstrated to be 〈 S nm. The doping levels of the nc-Si are found to be nonlinearly dependent on the original doping level of the wafers by x-ray photoelectron spectroscopy measurement. It is found that the nonlinear doping process will lead to the nonlinear chemical passivation and photoluminescence （I3L） intensity evolution. The doping, chemical passivation and PL mechanisms of the doped nc-Si samples prepared by mechanochemical synthesis are analyzed in detail.展开更多
As promising optoelectronic materials,lead sulfide quantum dots(PbS QDs)have attracted great attention.However,their applications are substantially limited by the QD quality and/or complicated synthesis.Herein,a facil...As promising optoelectronic materials,lead sulfide quantum dots(PbS QDs)have attracted great attention.However,their applications are substantially limited by the QD quality and/or complicated synthesis.Herein,a facile new synthesis is developed for highly monodisperse and halide passivated PbS QDs.The new synthesis is based on a heterogeneous system containing a PbCl_(2)-Pb(OA)_(2)solid-liquid precursor solution.The solid PbCl_(2)inhibits the diffusion of monomers and maintains a high oversaturation condition for the growth of PbS QDs,resulting in high monodispersities.In addition,the PbCl_(2)gives rise to halide passivation on the PbS QDs,showing excellent stability in air.The high monodispersity and good passivation endow these PbS QDs with outstanding optoelectronic properties,demonstrated by a 9.43%power conversion efficiency of PbS QD solar cells with a bandgap of~0.95 eV(1,300 nm).We believe that this heterogeneous strategy opens up a new avenue optimizing for the synthesis and applications of QDs.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51735009)State Key Lab of Mechanical System and Vibration Project of China(Grant No.MSVZD202008)National Aerospace Science Foundation of China(040102).
文摘To explore hostile extraterrestrial landforms and construct an engineering prototype,this paper presents the task-oriented topology system synthesis of reconfigurable legged mobile lander(ReLML)with three operation modes from adjusting,landing,to roving.Compared with our preceding works,the adjusting mode with three rotations(3R)provides a totally novel exploration approach to geometrically matching and securely arriving at complex terrains dangerous to visit currently;the landing mode is redefined by two rotations one translation(2R1T),identical with the tried-and-tested Apollo and Chang'E landers to enhance survivability via reasonable touchdown buffering motion;roving mode also utilizes 2R1T motion for good motion and force properties.The reconfigurable mechanism theory is first brought into synthesizing legged mobile lander integrating active and passive metamorphoses,composed of two types of metamorphic joints and metamorphic execution and transmission mechanisms.To reveal metamorphic principles with multiple finite motions,the finite screw theory is developed to present the procedure from unified mathematical representation,modes and source phase derivations,metamorphic joint and limb design,to final structure assembly.To identify the prototype topology,the 3D optimal selection matrix method is proposed considering three operation modes,five evaluation criteria,and two topological subsystems.Finally,simulation verifies the whole task implementation process to ensure the reasonability of design.
文摘When Kant discusses the comprehensive role of transcendental imagination,he mentions the role of an empirical synthesis,which is the basis of perceptual activity,but if it is based on empirical synthesis then the contradiction of a priori comprehensive ability and empirical synthesis has occurred,and the relationship between active synthesis and passive synthesis of consciousness has now become a problem that must be solved.The description of the association idea has already incorporated the passive synthesis component,which actually provides a solution to this contradiction.
基金Supported by the National Natural Science Foundation of China under Grant No 61575216
文摘A series of boron- and phosphorus-doped silicon wafers are used to prepare a series of doped silicon nanocrystals （nc-Si） by high-energy ball milling with carboxylic acid-terminated surface. The sizes of the nc-Si samples are demonstrated to be 〈 S nm. The doping levels of the nc-Si are found to be nonlinearly dependent on the original doping level of the wafers by x-ray photoelectron spectroscopy measurement. It is found that the nonlinear doping process will lead to the nonlinear chemical passivation and photoluminescence （I3L） intensity evolution. The doping, chemical passivation and PL mechanisms of the doped nc-Si samples prepared by mechanochemical synthesis are analyzed in detail.
基金supported by the National Key R&D Program of China(Nos.2021YFA0715502 and 2021YFA0715500)the National Natural Science Foundation of China(Nos.61974052 and 61904065),the Innovation Project of Optics Valley Laboratory(No.OVL2021BG009)+2 种基金the Fund from Science,Technology and Innovation Commission of Shenzhen Municipality(No.GJHZ20210705142540010)the Key R&D Program of Hubei Province(No.2021BAA014)the International Science and Technology Cooperation Project of Hubei Province(No.2021EHB010).
文摘As promising optoelectronic materials,lead sulfide quantum dots(PbS QDs)have attracted great attention.However,their applications are substantially limited by the QD quality and/or complicated synthesis.Herein,a facile new synthesis is developed for highly monodisperse and halide passivated PbS QDs.The new synthesis is based on a heterogeneous system containing a PbCl_(2)-Pb(OA)_(2)solid-liquid precursor solution.The solid PbCl_(2)inhibits the diffusion of monomers and maintains a high oversaturation condition for the growth of PbS QDs,resulting in high monodispersities.In addition,the PbCl_(2)gives rise to halide passivation on the PbS QDs,showing excellent stability in air.The high monodispersity and good passivation endow these PbS QDs with outstanding optoelectronic properties,demonstrated by a 9.43%power conversion efficiency of PbS QD solar cells with a bandgap of~0.95 eV(1,300 nm).We believe that this heterogeneous strategy opens up a new avenue optimizing for the synthesis and applications of QDs.
