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
In our efforts to construct new metal-organic frameworks （MOFs） by template-directing method, a new cadmium oxalate, [Co（NH3）612[Cds（C204）ll（H20）4].8H20 （denoted HNU-1 ）, has been synthesized under hydrother...In our efforts to construct new metal-organic frameworks （MOFs） by template-directing method, a new cadmium oxalate, [Co（NH3）612[Cds（C204）ll（H20）4].8H20 （denoted HNU-1 ）, has been synthesized under hydrothermal condition in the presence of C0（NH3）6C13, The crystal structure of HNU-1 was determined by single-crystal X-ray diffraction （monoclinic, C2/c）, a = 11.126（2）A, b = 17.361 （4）,A, c = 16.119（3）A, fi = 102.40（3）, V = 3040.8（10） A and Z = 8. The open framework of HNU-1 contains 12-ring channels and exhibits a 5-connected sqp topological network with dinuclear Cd（ll） clusters acting as nodes. The Co（NH3）63＋ cations and unusual hydrogen-bonded （H20）4 clusters are found in the 12-ring channels with an alternative arrangement. It is believed that the （H20）4 clusters play a co-templating role in the crystallization of HNU-1.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.
基金supported by the National Natural Science Foundation of China (No. 21101047)the Program for New Century Excellent Talents in University (No. NCET-11-0929)+1 种基金the Natural Science Foundation of Hainan Province (No. 211010)the Priming Scientifc Research Foundation of Hainan University (No. kyqd1051)
文摘In our efforts to construct new metal-organic frameworks （MOFs） by template-directing method, a new cadmium oxalate, [Co（NH3）612[Cds（C204）ll（H20）4].8H20 （denoted HNU-1 ）, has been synthesized under hydrothermal condition in the presence of C0（NH3）6C13, The crystal structure of HNU-1 was determined by single-crystal X-ray diffraction （monoclinic, C2/c）, a = 11.126（2）A, b = 17.361 （4）,A, c = 16.119（3）A, fi = 102.40（3）, V = 3040.8（10） A and Z = 8. The open framework of HNU-1 contains 12-ring channels and exhibits a 5-connected sqp topological network with dinuclear Cd（ll） clusters acting as nodes. The Co（NH3）63＋ cations and unusual hydrogen-bonded （H20）4 clusters are found in the 12-ring channels with an alternative arrangement. It is believed that the （H20）4 clusters play a co-templating role in the crystallization of HNU-1.
