Modifying the Properties of Tungsten Based Plasma Facing Materials with Single-Wall Carbon Nanotubes

Tungsten is one of the best candidates for plasma-facing components in fusion reactors owing to its unique properties. But disadvantages such as its brittleness and high ductile-to-brittle transition temperature have restricted its fusion energy application. Single-walled carbon nanotubes （SWCNTs） have the potential to be used as reinforcements due to their excellent mechanical properties. A new method of modifying the properties of tungsten by doping with SWCNTs was introduced. An efficient way of dispersing SWCNTs into the tungsten matrix with strong interfaces by heterocoagulation and ultrasonication was employed, and hot explosive compaction （HEC） technology was selected to compact and sinter the composite powders. The sintering properties, microstructure, densification effect, thermal conductivity, hardness and fracture toughness of the obtained SWCNTs/W bulk samples were tested, and compared with pure tungsten. The influences of SWCNTs on these properties and the main toughening mechanism of SWCNTs in a tungsten matrix were discussed.     

硝酸法纯化碳纳米管的研究

本文采用YNi2合金为催化剂使用电弧放电的方法制备单壁碳纳米管.采用硝酸回流法进行处理,分别经过超声、回流、水洗、研磨、培烧,得到较纯净的碳纳米管.分别用近红外光谱、拉曼光谱、热重分析进行表征.纯化后的碳纳米管可以进一步用来化学修饰、金属和半导体性的分离等.     

碳纳米管超薄膜实现可控制备

中科院苏州纳米技术与纳米仿生研究所的科研人员日前提出一种新颖巧妙的方法,多次可控制备性能均一的自支持单壁碳纳米管超薄膜。研究人员利用水的表面张力,层层剥离出厚度、尺寸及性能均一的单壁碳纳米管超薄膜,制备的     

氨基-β-环糊精-单壁碳纳米管-二茂铁修饰电极对抗坏血酸的电化学行为研究

合成制备了氨基-β-环糊精(NH2-β-CD),然后通过主客体反应将NH2-β-CD与二茂铁(Fc)形成稳定的包合物,再与单壁碳纳米管(SWCNTs)复合后得到NH2-β-CD/Fc/SWCNTs复合膜修饰电极。通过循环伏安法研究该修饰电极对抗坏血酸(AA)的电催化行为。结果表明,在pH7.0的磷酸盐缓冲溶液(PBS)中,电位范围在-0.2～0.6V内,峰电流的变化值与抗坏血酸的浓度在1×10-5～1×10-3mol/L范围内成良好的线性关系,检出限为3.6×10-7mol/L。当用于模拟样品的测定,加标回收率为98.3%～100.8%,效果良好。     

基于单壁碳纳米管可饱和吸收体的被动锁模光纤激光器研究

基于单壁碳纳米管(SWCNTs)作为光学可饱和吸收体(SA)的恢复时间快(<1ps)、饱和光强低、锁模自启动、工作光谱范围宽且制备方法简单、成本低、化学稳定性好、易与光纤兼容等优点,利用SWCNTs-SA实现了稳定脉冲序列输出的实验结果。利用聚甲基丙烯酸甲酯(PMMA)易成膜且机械性能良好的特点,将SWCNTs与PMMA一起分散在二氯化苯(DCB)溶液中,运用光学诱导作用将SWCNTs吸附在单模光纤(SMF)端面,并加热固化成膜。在光纤激光器环形腔结构中引入SWCNT/PMMA薄膜作为SA,获得了具有稳定的重复频率为8.366MHz的基频锁模脉冲序列,其中心波长在1 562nm,脉冲宽度为1.2ps。     

单壁碳纳米管的研究进展

单壁碳纳米管是一种新型纳米材料,其制备方法有石墨电弧放电法、化学气相沉积法（又称催化裂解法）和激光蒸发法。化学气相沉积法是产业化生产单壁碳纳米管的有效方法。碳纳米管强度高、密度低,具有奇特的光学、电磁、热学、储氢性能等,广泛应用于现代科技中航空、航天、军事、医学等科学技术领域。     

Effects of gamma irradiation for sterilization on aqueous dispersions of length sorted carbon nanotubes

There is currently great interest in the potential use of carbon nanotubes as delivery vessels for nanotherapeutics and other medical applications. However, no data are available on the effects of sterilization methods on the properties of nanotube dispersions, the form in which most medical applications will be processed. Here we show the effects of gamma irradiation from a ⁶⁰Co source on the dispersion and optical properties of single-wall carbon nanotubes in aqueous dispersion. Samples of different length-refined populations were sealed in ampoules and exposed to a dose of approximately 28 kGy, a level sufficient to ensure sterility of the dispersions. In contrast to literature results for solid-phase nanotube samples, the effects of gamma irradiation on the dispersion and optical properties of the nanotube samples were found to be minimal. Based on these results, gamma irradiation appears sufficiently non-destructive to be industrially useful for the sterilization of nanotube dispersions.     

Tunable separation of single-walled carbon nanotubes by dual-surfactant density gradient ultracentrifugation

We present a systematic study of the effects of surfactants in the separation of single-walled carbon nanotubes (SWNTs) by density gradient ultracentrifugation (DGU). Through analysis of the buoyant densities, layer positions, and optical absorbance spectra of SWNT separation using the bile salt sodium deoxycholate (DOC) and the anionic salt sodium dodecyl sulfate (SDS), we clarify the roles and interactions of these two surfactants in yielding different DGU outcomes. The separation mechanism described here can also help in designing new DGU experiments by qualitatively predicting outcomes of different starting recipes, improving the efficacy of DGU and simplifying post-DGU fractionation.      

Polarized light microscopy and spectroscopy of individual single-walled carbon nanotubes

Polarized light microscopy (PLM) is used to image individual single-walled carbon nanotubes (SWNTs) suspended in air across a slit opening. The imaging contrast relies on the strong optical anisotropy typical of SWNTs. We combine PLM with a tunable light source to enable hyperspectral excitation spectroscopy and nanotube chirality assignment. Comparison with fluorescence microscopy and spectroscopy confirms the assignment made with PLM. This represents a versatile new approach to imaging SWNTs and related structures.      

单壁碳纳米管应力传感器研究取得新进展

国家纳米科学中心孙连峰研究员小组的刘政在攻读博士期间发现,利用单壁碳纳米管薄膜两端的开路电压可以构建成高性能的应力传感器。他们把极性液滴在悬空碳纳米管薄膜和液滴之间产生毛细管桥,然后对碳纳米管薄膜施加一定作用的应力。