To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,wh...To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.展开更多
In the fabrication process of nanoelectronic device arrays based on single-wall carbon nanotube(SWCNT),oriented alignment of SWCNTs and property modification of metallic SWCNTs in the array are the key problems to be ...In the fabrication process of nanoelectronic device arrays based on single-wall carbon nanotube(SWCNT),oriented alignment of SWCNTs and property modification of metallic SWCNTs in the array are the key problems to be solved.Pulse gas alignment with substrate downward tilt is proposed to realize the controllable alignment of SWCNTs.Experimental results demonstrate that 84%SWCNTs are aligned in-15°―15°angular to the pulse gas direction.A modified nanomanipulation technology based on atomic force microscope(AFM)is utilized to perform various kinds of SWCNT manipulation,such as SWCNT separation from the"Y"CNT,catalyst removal from the SWCNT end,continual nano buckles fabrication on SWCNT and even stretching to break,which provides a feasible way to modify the size,shape and the electrical property of SWCNTs.展开更多
The capability to image, as well as control and manipulate single molecules such as nucleic acids(DNA or RNA) can greatly enrich our knowledge of the roles of individual biomolecules in cellular processes and their be...The capability to image, as well as control and manipulate single molecules such as nucleic acids(DNA or RNA) can greatly enrich our knowledge of the roles of individual biomolecules in cellular processes and their behavior in native environments. Here we summarize the recent advances of single nucleic acid imaging based on optical observation and force manipulation. We start by discussing the superiority of single molecule image, the central roles nucleic acids play in biosystems, and the significance of single molecule image towards nucleic acids. We then list a series of representative examples in brief to illustrate how nucleic acid of various morphologies has been imaged from different aspects, and what can be learned from such characterizations. Finally,concluding remarks on parts of which should be improved and outlook are outlined.展开更多
基金Supported by the National Natural Science Foundation of China(No.11672290)
文摘To eliminate the load weight limit of carrier rockets and reduce the burden on support structures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules,which requires smooth operation of assembly robots,and flexible force control technology is necessary. A ground demonstration system is presented for in-orbit assembly focusing on flexible force control. A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity. For translation and rotation,an algorithm for flexible control is proposed. A ground transportation demonstration verifies accuracy and smoothness of flexible force control,and the transportation and assembly task is completed automatically. The proposed system is suitable for the development of in-orbit assembly robots.
基金the National High Technology Research and Development Program(863 Program No.2006AA04Z320)Excellent Young Scholars Training Grant of Liaoning Province(Grant No.2005220025)
文摘In the fabrication process of nanoelectronic device arrays based on single-wall carbon nanotube(SWCNT),oriented alignment of SWCNTs and property modification of metallic SWCNTs in the array are the key problems to be solved.Pulse gas alignment with substrate downward tilt is proposed to realize the controllable alignment of SWCNTs.Experimental results demonstrate that 84%SWCNTs are aligned in-15°―15°angular to the pulse gas direction.A modified nanomanipulation technology based on atomic force microscope(AFM)is utilized to perform various kinds of SWCNT manipulation,such as SWCNT separation from the"Y"CNT,catalyst removal from the SWCNT end,continual nano buckles fabrication on SWCNT and even stretching to break,which provides a feasible way to modify the size,shape and the electrical property of SWCNTs.
基金supported by the National Natural Science Foundation of China (21525523, 21574048, 21375042, 21405054)the National Basic Research Program of China (2015CB932600, 2013CB933000)+1 种基金the Special Fund for Strategic New Industry Development of Shenzhen, China (JCYJ20150616144425376)1000 Young Talent (to Fan Xia)
文摘The capability to image, as well as control and manipulate single molecules such as nucleic acids(DNA or RNA) can greatly enrich our knowledge of the roles of individual biomolecules in cellular processes and their behavior in native environments. Here we summarize the recent advances of single nucleic acid imaging based on optical observation and force manipulation. We start by discussing the superiority of single molecule image, the central roles nucleic acids play in biosystems, and the significance of single molecule image towards nucleic acids. We then list a series of representative examples in brief to illustrate how nucleic acid of various morphologies has been imaged from different aspects, and what can be learned from such characterizations. Finally,concluding remarks on parts of which should be improved and outlook are outlined.
