The selection and modulation of the static and dynamic units within molecular-scale actuators,particularly regarding framework structures,are critical for initiating synergistic inter-and intramolecular motions.Howeve...The selection and modulation of the static and dynamic units within molecular-scale actuators,particularly regarding framework structures,are critical for initiating synergistic inter-and intramolecular motions.However,achieving controllable macroscopic mechanical switching through the collective transfer of microscopic motion while minimizing energy dissipation presents a significant challenge.This paper reports a two-dimensional magnetic coordination framework,Fe(tpe)(NCBH_(3))_(2)(tpe=1,1,2,2-tetra(pyridin-4-yl)ethene,1),synthesized by the minimally sized,planar tetradentate pyridine-based tpe ligand in conjunction with the precursor Fe(NCBH_(3))_(2).A single-crystal-to-single-crystal(SCSC)transformation,occurring via the adsorption and desorption of C_(2)Cl_(4) vip molecules,is directly associated with the activation of spin crossover(SCO)and CO_(2)/C_(2)H_(2) separation performance,correlating with the overall elastic frustration and toughness present in the framework.The establishment of multiple C–Hδ+⋯Hδ−–B dihydrogen bonds surrounding the tpe ligand facilitates its effective function as a static unit,simultaneously augmenting cooperativity with the Fe(NCBH_(3))_(2) acting as a dynamic unit,thereby enabling a macroscopic shape change in the free single crystal with reduced energy dissipation.The spin transition of the Fe2+metal center,activated by SCSC transformation and serving as a driving force for crystal macroscopic deformation,provides new insights into the mechanism of structural adaptability in frameworks and designing novel molecular machines.展开更多
There are 140 beam position monitors （BPMs） in the Shanghai Synchrotron Radiation Facility （SSRF） storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum...There are 140 beam position monitors （BPMs） in the Shanghai Synchrotron Radiation Facility （SSRF） storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment （BBA） method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.展开更多
基金funded by the Ningbo Soft Science Science Research Program(2023R002)Ningbo Natural Science Foundation(2022J096)+1 种基金National Natural Science Foundation of China(21571110)Natural Science Foundation of Zhejiang province(LY18B010003).
文摘The selection and modulation of the static and dynamic units within molecular-scale actuators,particularly regarding framework structures,are critical for initiating synergistic inter-and intramolecular motions.However,achieving controllable macroscopic mechanical switching through the collective transfer of microscopic motion while minimizing energy dissipation presents a significant challenge.This paper reports a two-dimensional magnetic coordination framework,Fe(tpe)(NCBH_(3))_(2)(tpe=1,1,2,2-tetra(pyridin-4-yl)ethene,1),synthesized by the minimally sized,planar tetradentate pyridine-based tpe ligand in conjunction with the precursor Fe(NCBH_(3))_(2).A single-crystal-to-single-crystal(SCSC)transformation,occurring via the adsorption and desorption of C_(2)Cl_(4) vip molecules,is directly associated with the activation of spin crossover(SCO)and CO_(2)/C_(2)H_(2) separation performance,correlating with the overall elastic frustration and toughness present in the framework.The establishment of multiple C–Hδ+⋯Hδ−–B dihydrogen bonds surrounding the tpe ligand facilitates its effective function as a static unit,simultaneously augmenting cooperativity with the Fe(NCBH_(3))_(2) acting as a dynamic unit,thereby enabling a macroscopic shape change in the free single crystal with reduced energy dissipation.The spin transition of the Fe2+metal center,activated by SCSC transformation and serving as a driving force for crystal macroscopic deformation,provides new insights into the mechanism of structural adaptability in frameworks and designing novel molecular machines.
文摘There are 140 beam position monitors （BPMs） in the Shanghai Synchrotron Radiation Facility （SSRF） storage ring used for measuring the closed orbit. As the BPM pickup electrodes are assembled directly on the vacuum chamber, it is important to calibrate the electrical center offset of the BPM to an adjacent quadrupole magnetic center. A beam based alignment （BBA） method which varies individual quadrupole magnet strength and observes its effects on the orbit is used to measure the BPM offsets in both the horizontal and vertical planes. It is a completely automated technique with various data processing methods. There are several parameters such as the strength change of the correctors and the quadrupoles which should be chosen carefully in real measurement. After several rounds of BBA measurement and closed orbit correction, these offsets are set to an accuracy better than 10 μm. In this paper we present the method of beam based calibration of BPMs, the experimental results of the SSRF storage ring, and the error analysis.
