Using coinage metal （Cu（Ⅱ）, Ag（Ⅰ）） hinges, two sets of heterometallic molecular capsules with analogous open-ended cavities were prepared based on the half-sandwich rhodium fragments. In the case of [Rh4Cu4] c...Using coinage metal （Cu（Ⅱ）, Ag（Ⅰ）） hinges, two sets of heterometallic molecular capsules with analogous open-ended cavities were prepared based on the half-sandwich rhodium fragments. In the case of [Rh4Cu4] cages, up to six-fold-stacked host-guest structures were formed by varying the cavity＇s dimensions. Moreover, the series of capsules were demonstrated to self-fine-tune to form multi-heteroguest arrays via favourable donor-acceptor interactions and Ag-π interactions, as evidenced from single-crystal X-ray analysis.展开更多
Very long and open aligned carbon nanotubes that reach about 2 mm long, an order of magnitude longer than previously reached, have been prepared by chemical vapor deposition over silica dioxide substrates on the surfa...Very long and open aligned carbon nanotubes that reach about 2 mm long, an order of magnitude longer than previously reached, have been prepared by chemical vapor deposition over silica dioxide substrates on the surface, where iron/silica nano-composite particles are evenly positioned. The nanotubes are naturally opened at the bottom ends. The growth mechanism of the very long and open-ended nanotubes is also discussed.展开更多
Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently pr...Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.展开更多
基金This work was supported by the National Natural Science Foundation of China （Nos. 21531002, 21720102004） and the Shanghai Science Technology Committee （No. 13JC1400600）. Guo-Xin Jin thanks the Alexander yon Humboldt Foundation for a Humboldt Research Award.
文摘Using coinage metal （Cu（Ⅱ）, Ag（Ⅰ）） hinges, two sets of heterometallic molecular capsules with analogous open-ended cavities were prepared based on the half-sandwich rhodium fragments. In the case of [Rh4Cu4] cages, up to six-fold-stacked host-guest structures were formed by varying the cavity＇s dimensions. Moreover, the series of capsules were demonstrated to self-fine-tune to form multi-heteroguest arrays via favourable donor-acceptor interactions and Ag-π interactions, as evidenced from single-crystal X-ray analysis.
文摘Very long and open aligned carbon nanotubes that reach about 2 mm long, an order of magnitude longer than previously reached, have been prepared by chemical vapor deposition over silica dioxide substrates on the surface, where iron/silica nano-composite particles are evenly positioned. The nanotubes are naturally opened at the bottom ends. The growth mechanism of the very long and open-ended nanotubes is also discussed.
基金supported by the Russian Science Foundation(Grant No.18-72-10137)。
文摘Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.
