Preparation of cellulose I nanowhiskers with a mildly acidic aqueous ionic liquid: reaction efficiency and whiskers attributes

Cellulose I nanowhiskers were prepared in relatively high yield (48 ± 2 %) by single-stage hydrolysis of microcrystalline cellulose with an aqueous solution of 1-butyl-3-methylimidazolium hydrogen sulfate ([Bmim]HSO₄). This reaction occurred under mildly acidic reaction conditions with an [H⁺]/[AGU] ratio of 0.24 mol/mol, i.e., 2 orders of magnitude lower than with concentrated sulfuric acid. The nanowhiskers exhibited small width and width distribution and also smaller length than nanowhiskers obtained with concentrated acid. With a relatively low content of sulfur they also exhibited higher thermal stability than whiskers obtained with concentrated sulfuric acid. The lower solvating power of the aqueous ionic liquid compared to that of concentrated sulfuric acid likely contributes to the greater hydrolysis efficiency in the present system.     

The development of hollow multishelled structure: from the innovation of synthetic method to the discovery of new characteristics

Hollow multishelled structure(HoMS)is one of the most promising multifunctional structures.The high complexity of its structure makes the general and controllable synthesis of HoMS rather challenging.By integration of multidisciplinary knowledge,a great achievement in HoMSs has been obtained in the past decade.Especially,the developed sequential templating approach has significantly boomed the progress of HoMS in composition and structure diversity and application area.The implementation of the temporal-spatial ordering in HoMS makes it indispensable in solving the key scientific problems in energy conversion,catalysis and drug delivery areas.Further development in HoMSs with novel intricate structures will bring new understandings.In this review,we systematically introduce the development history of HoMSs,summarize the inspiration inherited from the previous research on hollow structures,and discuss the milestones in the development of HoMSs,with a focus on the sequential templating approach for HoMS fabrication,attractive temporal-spatial ordering property and dynamic smart behavior for advanced applications.We hope to reveal the inherent relationship between the precise synthesis of HoMS and its highly tunable compositional and structural characteristics,and point out its future direction to boost HoMS area further.     

Controlled electropolymerization based on self-dimerizations of monomers

Electropolymerization is one of the most important methodologies to synthesize and develop conducting polymers. The complexity of the polymerization mechanism, ion doping processes and structural defects are considered to be symbiotic and unavoidable, making the stagnant state and huge band gap with advanced interdisciplinary research fields and important applications in the last three decades. Herein, we provide a point of view into controlled electropolymerization by regioselective activation reactions of monomers, where self-dimerizations instead of self-electropolymerizations were utilized. The resulting dimers play a role in the connections between functional building blocks to form functional polymers on demand. This account highlights the typical findings in controlled electropolymerizations as a forum for discussing new opportunities in exploiting novel designs and applications.     

Structural phase transition of vanadium at 69 GPa

A phase transition was observed at 63-69 GPa and room temperature in vanadium with synchrotron x-ray diffraction. The transition is characterized as a rhombohedral lattice distortion of the body-centered-cubic vanadium without a discontinuity in the pressure-volume data, thus representing a novel type of transition that has never been observed in elements. Instead of driven by the conventional s-d electronic transition mechanism, the phase transition could be associated with the softening of C44 trigonal elasticity tensor that originates from the combination of Fermi surface nesting, band Jahn-Teller distortion, and electronic topological transition.     

Lattice Distortion in Hollow Multi-Shelled Structures for Efficient Visible-Light CO2 Reduction with a SnS2/SnO2 Junction

Precise control of the micro-/nanostructures of nanomaterials, such as hollow multi-shelled structures (HoMSs), has shown its great advantages in various applications. Now, the crystal structure of building blocks of HoMSs are controlled by introducing the lattice distortion in HoMSs, for the first time. The lattice distortion located at the nanoscale interface of SnS₂/SnO₂ can provide additional active sites, which not only provide the catalytic activity under visible light but also improve the separation of photoexcited electron–hole pairs. Combined with the efficient light utilization, the natural advantage of HoMSs, a record catalytic activity was achieved in solid–gas system for CO₂ reduction, with an excellent stability and 100 % CO selectivity without using any sensitizers or noble metals.     

Stabilization of the Closed-Ring Isomer of Spiropyran by Amide Naphthotube in Water and Its Application in Naked-Eye Detection of Toxic Paraoxon

The thermodynamically unstable, colourless closed-ring isomer of spiropyran can be stabilized in water by the anti-configurational isomer of amide naphthotube. The influence of the binding on the thermodynamics and kinetics of spiropyran have been studied. The complex was further used to prepare a test paper that allows naked-eye detection of toxic paraoxon.     

随机生长误差对双腔型平顶法布里-珀罗滤波器的影响

在光网络中平顶滤波器可以有效地提高信道光检测的快速性和准确性。利用两个法布里珀罗腔间的串联耦合,可以构建出具有平顶透射特性的双腔型法布里珀罗滤波器。采用传输矩阵的方法,研究了随机生长误差对双腔型平顶滤波器透射特性的影响。模拟分析表明,当两个法布里珀罗腔的物理厚度差超过一个纳米时,在透射谱中就会出现两个高度不同的透射峰;解释了实测器件的透射谱中的双峰不对称性;用界面起伏的概念解释了实测滤波器带宽大于理论值的原因。理论分析与实验结果取得了较好的一致。