Carbon nanostructures produced through ion irradiation

Several nanostructures we produced by ion irradiation have been reviewed in this paper. By using ions to irradiate two ultrahigh molecular weight polyethylene targets respectively, it was found that small fullerenes C20 and C26 were grown, adding two members to the fullerene family. Meanwhile, crystalline diamonds also have been produced by Ar+ ions irradiation of graphite. In the experiment of double ions Ni+ and Ar+ irradiation, nanoscale argon bubbles formed. On the other side, when multi-wall carbon nanotubes were irradiated by C+, many MWCNTs evolved to amorphous carbon nanowires and amorphous carbon nanotubes. And there are possible welding in the crossed nanotubes.

Optical absorption of ion irradiated multi-walled carbon nanotube sheets in the visible to terahertz ranges

Optical absorption of Ar and H ion beam irradiated multi-walled carbon nanotube (MWCNT) sheets at various doses in the visible and terahertz spectral ranges was investigated.It was found that the optical absorption of MWCNT sheets in the visible range was decreased with increasing ion irradiation dose.Similar behavior was observed in terahertz range,where the optical absorption of MWCNT sheets in the range of 0 to 1.5 THz was also decreased with increasing ion irradiation dose.The optical absorption decreases in irradiated MWCNT sheets can be ascribed to the increase of defects in the irradiated MWCNTs.

γ射线与N离子辐照类金刚石薄膜的机理研究

对类金刚石 (以下简称 DLC)薄膜受 γ射线与 N离子辐照的结果进行了比较 .通过 Raman光谱分析得出 :γ射线辐照造成薄膜中 SP3C— H和 SP2 C— H键的减少及 SP3C— C键的增加 ,与此同时氢原子结合成氢分子 ,并从膜中释出 ,薄膜的类金刚石特征更加明显 .当辐照剂量达 1 0× 1 0 4Gy时 ,SP3C—H键减少了约 5 0 % .N离子辐照使 DLC薄膜中 SP3C— C键、SP2 C—H键及 SP3C—H键的含量均变少 ,并伴随着氢分子的释出 ,直接导致 DLC薄膜的进一步石墨化 ,其对 SP3C—H及 SP2 C— H键的破坏程度远大于γ射线 .

碳离子辐照对菘蓝药性品质和分子水平的诱变效应

以野生菘蓝种子为材料,以不同剂量的碳离子(12 C6+)进行辐照处理(辐照剂量分别为30Gy、60Gy、90Gy、120Gy),分析12 C6+辐照对菘蓝种子萌发、幼苗生长、主要药用成分含量及其基因和蛋白质多态性变化的影响,为菘蓝品质育种、分子生物学研究和重离子辐照诱变的应用提供依据。结果显示:(1)12 C6+辐照处理后菘蓝的成苗率和根鲜重均随辐照剂量增加而逐步显著降低,其中30Gy处理对菘蓝生长抑制程度最小,但处理后菘蓝根中的主要药效成分4(3H)喹唑酮和靛玉红的含量增加幅度最大且最高,分别为野生型的2.2倍和2.3倍。(2)SRAP分子标记分析表明,菘蓝基因组的变异度随着辐照强度的增强而增大,其中30Gy处理的突变体与野生型相比有33.59%的多态性变异。(3)SDS-PAGE考马斯亮蓝染色和磷酸化染色分析表明,菘蓝的总蛋白和磷酸化蛋白表达水平均随辐照剂量变化出现了不同程度的改变,但并不与辐照强度呈正相关,说明植物在防御重离子辐照伤害时存在补偿机制。研究发现,30Gy的12 C6+辐照是菘蓝诱变的最佳剂量,能够显著提高其有效成分的含量,为优质菘蓝诱变育种奠定了基础。

Ar离子束辐照下多壁碳纳米管网络的导电性增强

用Ar离子束辐照800K高温下的多壁碳纳米管(MWCNT)网络,注量为2×1016/cm2时,MWCNT网络的导电性提高～80%。实验结果表明,离子束辐照可通过在多壁碳纳米管间的引入连接改善多壁碳纳米管间的电学接触,制备高导电性的透明碳纳米管网络。

利用粒子辐照技术实现碳纳米管向金刚石的转变

采用低能氢等离子体和中能C+离子束辐照技术相结合的方法,实现了碳纳米管向金刚石纳米晶粒的转变,完成了一个从有序(碳纳米管)到无序(无定形碳纳米线)再到有序(金刚石纳米晶)的转变过程。利用透射电子显微镜(TEM)、选区电子衍射(SAD)和拉曼光谱(Raman)等研究了晶粒的微观结构,并对纳米金刚石晶粒的生成机理进行了初步探讨。

离子束辐照的碳纳米管及其物性研究

离子束辐照通常被认为导致材料产生缺陷,形成无序结构,从而破坏材料的性能。但是,最近利用离子束辐照碳纳米管的实验显示离子束辐照碳纳米管形成无定形的过程不能用传统的离子束辐照材料的机制来解释,离子束辐照可导致碳纳米管形成一些自组装结构,如无定形碳纳米结和碳纳米管连接结等。研究还发现离子束辐照的碳纳米管薄膜在导电性和场发射性能方面都能得到明显的增强。