中国排球代表运动员:有化学高手吗

能帮忙翻译下吗，感激不尽啊
Several methods [1–3] for large scale synthesis of
carbon nanotubes have opened the door to studying their
physical and chemical properties, which were expected to
be unique [4,5]. However, the as-prepared carbon
nanotubes usually contain a large amount of impurities,
such as metal particles, amorphous carbon, and multishell
carbon nanocapsules. Such impurities are a serious impedi-
ment to detailed characterization of the properties of the
nanotubes.
There are several reports [6–12] on purification of
multi-walled carbon nanotubes (MWNTs). One of the
efficient purification methods was oxidation in air at
temperatures around 7508C [6]. Owing to the small
difference in reactivity between MWNTs and nanoparti-
cles, pure MWNTs were obtained in the risk of burning off
99 wt.% of the sample after prolonged oxidation [6].
Another purification method was based on liquid-phase
oxidation using KMnO /H SO solution [7]. Electron 4 2 4
microscopy images showed that the residual carbon sample
contained exclusively pure nanotubes, but that the tubes
appeared to be severely damaged [7]. Chen et al. [8]
reported an interesting approach to the purification of
nanotubes which was based on graphite intercalation. Their
result showed that the nanotubes were less susceptible to
bromination than the carbon nanoparticles, and subsequent
heating in air at 5308C resulted in preferential destruction
of the intercalated carbon. However, the metal particles
still remained in the product.
In this paper, we report a multi-step method of purifying
carbon nanotubes, which could effectively remove metal
particles, amorphous carbon and multishell carbon
nanocapsules. Furthermore the yield could approach 50%.
In order to elucidate the effect of bromination on purifying
MWNTs, a multi-step method with bromination and
without bromination were used to purify the same batch of
as-prepared product. The result revealed that bromination
played a great role in purifying MWNTs.