Study of the Formation of Nano-Networks in Colloidal Particles

The authors studied the formation of a wafer-scale network of connected colloidal beads by reactive ion etching. The dimensions of the connections have been studied as a function of etching time for colloidal beads of different sizes, and could be well controlled. The authors have found that the nano-network forms and disappears for the same time of etching independent of the diameter of the polystyrene beads. With recent interest of connected colloidal networks in various optical sensing applications, such as photonic crystals, as surface-enhanced Raman scattering substrates, the studies have potential uses in the development of wafer-scale nanophotonic sensors.     

碳纳米物质的直接激光飞行时间质谱分析

用含金属氧化物的石墨棒作电极 ,在氩气氛中利用弧放电制备碳纳米类物质。用于分析测定的物质是碳纳米类物质 C6 0 、C70 、C76 、C78、C84 以及 La@C82 ,得到其在正离子状态下的分子离子及碎片离子。碳纳米类分子以 C2 -碎片丢失的方式进行特征解离。对不同碳纳米物质的系列碎片峰的强度进行研究结果表明 :碎片[M-C2 n H]+丰度随球形分子的体积的增大而增加 ,而且碎片 [M-C2 n H]+的丰度略大于 [M-C2 n]+。激光飞行时间质谱分析为碳纳米分子结构及其稳定性提供了十分有用的信息     

分子通信研究综述

基于生物启发的分子通信是一种以生物化学分子作为信息载体、用于互联纳米机器以组成分布式纳米网络的通信技术。归纳了分子通信的定义和特性,以及基于分子通信纳米网络的应用领域和国内外相关领域的重要科研活动与项目;介绍了分子通信的系统结构,其中重点描述了信息分子的传输机制;分别从系统的设计与实现、理论研究和基于分子通信的纳米网络技术3个方向总结和分析了分子通信的研究与发展现状,并展望了未来的研究方向。     

Sundew adhesive: a naturally occurring hydrogel

Bioadhesives have drawn increasing interest in recent years, owing to their eco-friendly, biocompatible and biodegradable nature. As a typical bioadhesive, sticky exudate observed on the stalked glands of sundew plants aids in the capture of insects and this viscoelastic adhesive has triggered extensive interests in revealing the implied adhesion mechanisms. Despite the significant progress that has been made, the structural traits of the sundew adhesive, especially the morphological characteristics in nanoscale, which may give rise to the viscous and elastic properties of this mucilage, remain unclear. Here, we show that the sundew adhesive is a naturally occurring hydrogel, consisting of nano-network architectures assembled with polysaccharides. The assembly process of the polysaccharides in this hydrogel is proposed to be driven by electrostatic interactions mediated with divalent cations. Negatively charged nanoparticles, with an average diameter of 231.9 ± 14.8 nm, are also obtained from this hydrogel and these nanoparticles are presumed to exert vital roles in the assembly of the nano-networks. Further characterization via atomic force microscopy indicates that the stretching deformation of the sundew adhesive is associated with the flexibility of its fibrous architectures. It is also observed that the adhesion strength of the sundew adhesive is susceptible to low temperatures. Both elasticity and adhesion strength of the sundew adhesive reduce in response to lowering the ambient temperature. The feasibility of applying sundew adhesive for tissue engineering is subsequently explored in this study. Results show that the fibrous scaffolds obtained from sundew adhesive are capable of increasing the adhesion of multiple types of cells, including fibroblast cells and smooth muscle cells, a property that results from the enhanced adsorption of serum proteins. In addition, in light of the weak cytotoxic activity exhibited by these scaffolds towards a variety of mammal cells, evidence is sufficient to propose that sundew adhesive is a promising nanomaterial worth further exploitation in the field of tissue engineering.     

Preparation of basalt fiber@perovskite PbTiO3 core–shell composites and their effects on CH4 production from CO2 photoreduction

Newly designed composites of basalt fiber (BF) core–shells coated with TiO₂− and PbTiO₃ (BF@TiO₂ and BF@PbTiO₃, respectively) were introduced to improve CO₂ photoreduction to CH₄. A facile dipping method was used to construct the BF@TiO₂ and BF@PbTiO₃ materials with a three-dimensional nano-network microstructure. The composites were characterized by X-ray diffraction, scanning electron microscopy, and CO₂- and H₂O-TPD. The core@shell structure increased significantly the adsorption of CO₂ and H₂O gases on the nano-network microstructure, which effectively enlarged the microfiber/nanoparticle interface. BF@PbTiO₃ exhibited superior photocatalytic behavior, and produced 290 μmol g_cat⁻¹ L⁻¹ CH₄ gas after a 6 h reaction. These results were attributed to the effective CO₂ gas adsorption and inhibition of the recombination of photogenerated electron–hole pairs. A model for the enhanced photoactivity over basalt BF@PbTiO₃ was proposed. This highly stable core–shell 3D network structural composite is quite promising for use as a photocatalyst for the reduction of CO₂–CH₄.     

细菌分子通信和身体域纳米网络

纳米与生物技术的快速发展为身体域的分子通信研究提供了强有力的基础.笔者总结了细菌分子通信领域的最新研究进展,介绍了细菌接合传输和细菌分泌传输2种机制以及相关的实验和仿真结果.基于细菌分子通信,讨论了身体域纳米网络相关的中继组网技术,阐述了纳米生物技术的发展趋势和所面临的挑战.     

Phosphosilicate nano-network (PPSN)-Polybenzimidazole (PBI) composite electrolyte membrane for enhanced proton conductivity,durability and power generation of HT-PEMFC

Here we report a composite electrolyte membrane of Polybenzimidazole (PBI) with Phosphosilicate nano-network (PPSN) for enhanced proton conductivity, durability and power generation of high temperature polymer electrolyte membrane fuel cell (HT-PEMFC). Solid state proton conductor three dimensional Phosphosilicate nano-network (average particle size <10 nm) is synthesized using easy and low-cost sol gel method followed by ball milling and composited with PBI at different loading employing methane sulfonic acid (MSA) as solvent. The electrolyte membrane is characterized using FESEM, XRD, FTIR, TGA; proton conductivity, ion exchange capacity, water uptake and acid doping level, chemical stability and mechanical yield strength are measured and the membrane is tested for HT-PEMFC application. Property and performance mapping reveals that with 10% PPSN loading, composite (PPSN-PBI-10) membrane offers the maximum enhancement of all properties and power generation of HT-PEMFC, while beyond a critical loading (～22%) properties and performance deteriorate below that of pristine PBI. Using optimum loading of PPSN, compared to pristine PBI, a remarkable rise in water uptake and acid doping level is achieved that facilitates proton conduction; also in spite of the presence of Phosphoric acid in the PPSN filler, the maximum 47.5% enhancement of ultimate strength is attained. The performance of HT-PEMFC using composite PPSN-PBI unveil that almost 2 times (100%) enhancement of peak power generation (～0.73 W cm^?2) is achieved using PPSN-PBI-10 at 170 °C operating temperature compared to pristine PBI. This may be attributed to the facilitated proton conduction through the extended tunnelling network offered by PPSN. Incorporation of PPSN improves the durability; over 48 h only 16% decay in voltage is noticed using PPSN-PBI-10 membrane which is remarkably lower than the 31% decay of pristine PBI membrane.     

基于扩散的分子通信与身体域纳米网络

分子通信技术能够实现纳米尺度上的信息通信,由于其具有生物兼容性,可应用于身体域纳米网络,受到学术界的广泛关注.首先介绍了分子通信的研究和发展现状,描述了基于扩散的分子通信原理;给出了基于扩散的分子通信的身体域纳米网络的组网理论和方法,讨论了相应的信息理论研究成果;最后以微粒药物递送技术为例展望了基于扩散的分子通信理论在身体域纳米网络中的应用.