Smart Microcavity on the Tip of Multi-Core Optical Fiber for Gas Sensing

We designed and fabricated a smart microcavity sensor with a vertically coupled structure on the end face of a multi-core fiber using two-photon lithography technology. The influence of gap in vertical coupling structure on the resonance characteristics of bonding and anti-bonding modes in the transmission spectrum was studied through simulation and experiments. The results indicate that the bonding and anti-bonding modes generated by the vertical coupling of the two microcavities, as well as the changes in the radius and refractive index of the micro-toroid, and the distance between the microcavities caused by the absorption of vapor during the gas sensing process, exhibit different wavelength shifts for the two resonant modes. Smart microcavity sensors exhibit sensitivity and sensing characteristics. .

Structural Probing on the Sn-C(C5 ring)Bond of the Sn(Ⅱ)Metallocenes in Both the Solid State and the Temperature-dependent Solution Relaxation State

Various bond modes of the M-C（C5 ring） exist in metallocene compounds of group 14 heavier elements,mostly due to an intricate interaction between the lone electron pairs at the M center and the 6 p-electrons of the C5 ring.The tin（Ⅱ） metallocene complexes LSn R（L = HC[CMe（N-2,6-iPr2C6H3）]2,R = cyclopentadienyl,C5H5（1）; indenyl,C9H7（2）; fluorenyl,C（13）H9（3）） stabilized by the β-diketiminato ligand were prepared and utilized in the study on their solid and solution state structures.X-ray single-crystal diffraction data revealed an η~1-mode of the Sn-C（C5 ring） bond in each 1~3.However,the room temperature ~1H NMR spectral studies disclosed such a fluxional bonding mode in solution.The 119 Sn NMR studies suggested a quadruple coordination nature of the Sn center in 1 while the triple coordination manner was for the Sn atom in both 2 and 3.Then the variable-temperature（25~–75 ℃） ~1H NMR spectral studies for each 1~3 were performed,which detected the relaxation state structures of 1~3 at lower temperature.All of these results indicate a stereochemical activity of the lone electron pairs at the tin（Ⅱ） atom that definitely has an electronic interaction with the 6 p-electrons of the C5 ring.The observed Sn-C（C5 ring） bond modes appear influenced by either the metallocene size or the compound state existed.

Regulation mechanism for the formation and microwave absorbing performance of CNT/CoFe-MOF derived hierarchical composite

The structure design,performance analysis,and process optimization of CNT/MOF-derived hierarchical composite play an important role in the development of high-performance microwave absorbing materi-als.Herein,the preparation,morphology evolution,and electromag-netic wave absorption mechanism of CNT/MOF-derived hierarchical composite were systematically investigated.The regulation mechan-ism was revealed by studying the changes in the morphological characteristics,electromagnetic properties,and microwave absorbing performance of CNT/MOF-derived hierarchical composite under differ-ent process parameters.The results show that the morphological characteristics and interface bonding between CNT and MOF have a great impact on the absorptive capacity.The composite with com-position of 0.28Co/0.26Fe has a maximum absorption of−46 dB at 8.6 GHz and a thickness of 4 mm.In addition,the absorption band with reflection loss values of less than−20 dB can be operated with this thickness between 7.15 and 10.18 GHz,showing excellent absorbing ability and electromagnetic wave bandwidth.The regulation mechan-ism of CNT/MOF-derived hierarchical composite mainly depends on the effect of Lorentz force,the ion disorder of CoO-Fe_(2)O_(3) heterojunc-tion,and the spin polarization mechanism of free electrons.This study further improves the corresponding theoretical basis and new design principles,which provides technical support for the development of high-performance absorbing materials.