巴基葱及其电学特性研究

利用直流弧光放电法制备了巴基葱，高分辨透射电子显微镜分析表明这种巴基葱为空心椭球形，由１１层富勒烯组成。利用超高真空原子力显微镜和扫描隧道显微镜研究了巴基葱在高定向石墨基底上的行为和电学特性。巴基葱的扫描隧道谱结果表明，巴基葱的电学特性介于石墨和单层富勒烯之间。     

巴基葱及其电学特性研究

利用直流弧光放电法制备了巴基葱,高分辨透射电子显微镜分析表明这种巴基葱为空心椭球形,由11层富勒烯组成。利用超高真空原子力显微镜和扫描隧道显微镜研究了巴基葱在高定向石墨基底上的行为和电学特性。巴基葱的扫描隧道谱结果表明,巴基葱的电学特性介于石墨和单层富勒烯之间。     

巴基管（BUCKYTUBE）稳定性的研究

采用差热分析方法以及对用铸造法合成的Ｆｅ／Ｂｕｃｋｙｔｕｂｅ（译为巴基管，以下同此）复合材料中巴基管的热稳定性进行了深入的研究，结果表明：在Ａｒ气体保护下，巴基管在１４００℃时是稳定的；在Ｆｅ／Ｂｕｃｋｙｔｕｂｅ复合材料中，有一部分巴基管的结构被破坏，大量巴基管被保留下来，巴基管稳定的Ｆｅ／Ｂｕｃｋｙｔｕｂｅ复合材料的直接合成在动力学上是可行的。     

铁-巴基管复合材料的研究

采用直接熔化方法合成铁-巴基管复合材料,研究了复合材料淬火处理后的硬度及显微组织变化。实验结果表明:在适当的淬火工艺下,铁-巴基管复合材料硬度可达HRc65,而且比相同工艺下普通铁碳合金的硬度平均高出5～10HRc.显微组织分析发现淬火马氏体中有规则晶体外形的白亮相存在,波谱分析结果证明它们是贫铁相。差热分析结果表明直到1400℃的高温,巴基管没有相变。高分辨透射电镜观察到复合材料中弥散分布着巴基管,巴基管能在复合材料中稳定存在而起强化作用。     

巴基管的研究进展

巴基管的研究是纳米材料研究中的新领域。综述了巴基管的制备方法和化学氧化等方面的新进展。     

巴基球研究的新进展

自姜国科学家发现C_(60)以来,人们相继开发出这一新材料的各种用途,如作高温润滑剂,耐热、防水材料,超导材料等。本文对巴基球的发现、发展以及一些基本性质和用途作一总结和介绍。     

科学家破解巴基球形成之谜

据物理学家组织网报道，经过25年的探索，美国科学家们最近揭开了富勒烯家族中巴基球的笼状碳分子形成之谜。美国佛罗里达州立大学和美国国家科学基金会支持的国家高磁场实验室的研究团队取得的这一成果，     

多壁巴基纸/环氧复合材料拉伸性能的影响因素

采用抽滤法制备了多壁碳纳米管(MWCNTs)纸(又称巴基纸), 研究了巴基纸增强不同环氧基体复合材料(巴基纸复合材料)的拉伸性能及其断口形貌, 分析了MWCNT含量、 树脂基体拉伸性能以及巴基纸与树脂的界面黏附作用对复合材料拉伸性能的影响。结果表明: 在MWCNT质量分数小于39.1%范围内, 增加碳纳米管含量, 可显著提高巴基纸/环氧复合材料的拉伸性能; 巴基纸/环氧复合材料的拉伸强度和模量与树脂基体的性能密切相关, 其拉伸破坏形式受基体的脆韧性影响显著; 相比较而言, 巴基纸与树脂间的黏附功对巴基纸/环氧复合材料拉伸性能的影响不明显。     

碳纳米管的制备及研究

介绍了在直流电弧放电法制备富勒烯过程中，从阴电极表面收集到大量的碳纳米管及巴基葱，产生率达到５０％，并用电子显微镜对其进行了观察和初步研究。     

碳基天然气贮存材料

综述了碳基天然气储存材料的分类、特性和研究现状,并介绍了极有可能成为２１世纪吸附材料的纳米碳材料：富勒烯和巴基管。     

Kinetic Instability of Boron Heterofullerenes

Although boron heterofullerenes are produced abundantly in the gas phase, they cannot be isolated in macroscopic amounts. Those with two to six boron atoms were found to have minimum bond resonance energies (min BRE) of less than -0.100 |β|. All carbon-boron bonds have negative BREs, suggesting that boron atoms markedly destabilize nearby π bonds. on this theoretical basis, typical boron heterofullerenes are predicted to be kinetically very unstable and chemically very reactive. In contrast, the molecular anions with 60 π electrons of boron heterofullerenes are predicted to be kinetically much more stable. These anions do not have bonds wirh large negative BREs. Some of them may be isolable as salts or endohedral complexes. This study constitutes the first attempt to apply the BRE method to heteroconjugated systems.     

Kinetic Instability of Boron Heterofullerenes

Abstract

Although boron heterofullerenes are produced abundantly in the gas phase, they cannot be isolated in macroscopic amounts. Those with two to six boron atoms were found to have minimum bond resonance energies (min BRE) of less than -0.100 |β|. All carbon-boron bonds have negative BREs, suggesting that boron atoms markedly destabilize nearby π bonds. on this theoretical basis, typical boron heterofullerenes are predicted to be kinetically very unstable and chemically very reactive. In contrast, the molecular anions with 60 π electrons of boron heterofullerenes are predicted to be kinetically much more stable. These anions do not have bonds wirh large negative BREs. Some of them may be isolable as salts or endohedral complexes. This study constitutes the first attempt to apply the BRE method to heteroconjugated systems.     

Synthesis of carbon nanotubes by arc discharge in open air

In this work Carbon nanotubes have been synthesized by arc discharge in open air. A TIG welding ac/dc inverter was used as the power source for arc discharge. During each run of the arc discharge based synthesis, the anode was a low purity (approximately 85% C by weight) graphite rod. The effect of varying the atmosphere on the yield of soot of the carbon nanotube containing carbon soot has been studied. Various soots were produced, purified by oxidation and characterized to confirm formation of carbon nanotubes and their relative quality, using transmission electron microscopy, Raman spectroscopy, and XRD. It was found that the yield of soot formed on the cathode is higher when synthesis is carried out in open air than when carried out in a flowing argon atmosphere. When synthesized in open air, using a 7.2-mm-diameter graphite rod as anode, the yield of soot was around 50% by weight of the graphite consumed. Current and voltage for arcing were at identical starting values in all the experiments. This modified method does not require a controlled atmosphere as in the case of a conventional arc discharge method of synthesis and hence the cost of production may be reduced.     

碳包Ni纳米晶的形成及其特性

用直流碳弧法制备出碳包Ni金属纳米晶.在石墨阳极复合棒中掺入不同组份的Ni，研究其对碳包Ni纳米晶，富勒烯等碳微团特性的影响结果表明：碳包Ni纳米晶含Ni和石墨，不含碳化物和氧化物；纳米品数量随Ni增加而增加．而纳米晶的粒径出现极值；Ni催化碳微团石墨化并使C60／70产率下降；碳包Ni金属纳米晶单位质量的饱和磁化强度随Ni的增加而增加     

Arc Synthesis of Silicon-Doped Heterofullerenes in Plasma at Atmospheric Pressure

For the first time, an arc synthesis at atmospheric pressure was carried out for obtaining silicon-doped heterofullerenes C₅₂Si₈ and C₆₂Si₈. These molecules were detected in a pyridine extract from soot by mass spectrometry in amounts of no more than 1%. The abundance ratio of the heterofullerenes is the same as that for C₆₀/C₇₀ mixture. An explanation of the absence of heterofullerenes with lower number of Si atoms is given.     

A New Method to Obtain C60 and Higher Fullerenes

Abstract

In this paper we describe a new experimental method to produce fullerenes with substantial yield, based on the simple vaporisation of graphite rods in a low-frequency plasma jet. The proposed method is sustained by our earlier work on differently configured carbon structures produced by condensing carbon from vapor phase. Our goal is to provide a better-controlled, straightforward and low-cost method for generating large quantities of fullerene-containing carbon soot. A key feature of the vaporisation apparatus is that it is a combination between arc discharge and plasma jet dissociation. The vaporisation of the carbon rod is not driven by ohmic heating but rather by a discharge between the end of graphite rod and the cathode of the plasma-jet system. There are several attractive features of this procedure. First, variations in the parameters of plasma jet may be used to control systematically the size distribution of fullerene clusters. Secondly, this could be used for solid studies of larger fullerenes clusters since large clusters are only produced in low yield by the arc-discharge method. Also, we believe that there is great potential to investigate systematic doping of fullerene cluster using this technique since dopants can be easly introduced into the plasma jet prior to thermal dissociation.     

Microscope studies of the morphology and structure of carbon nanotubes

We have studied the morphologies and structures of carbon nanotubes (bucky-tubes) and carbon nanoparticles (buckyonions) using scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and scanning tunnelling microscopy (STM). By SEM the carbon nanotubes are observed with features similar to those of some fibrous whiskers grown from pyrolytic graphite. This growth feature is supported by transmission electron microscopy (TEM) observations. The TEM results show also that the graphitic sheets can be bent into curved shapes to cap the nanotubes or form the onions. In the curved graphitic sheets elastic strains induced by layer mismatches and dislocations are revealed. The STM observations on the nanotubes show a bundle-like morphology of the carbon nanotubes, and by atomic resolution images the zigzag and armchair atomic configurations may be identified. The results also show structural distortions which may be produced by folding the graphite sheets to create the nanotubes and are responsible for the lattice mismatch.     

A New Method to Obtain C60 and Higher Fullerenes

In this paper we describe a new experimental method to produce fullerenes with substantial yield, based on the simple vaporisation of graphite rods in a low-frequency plasma jet. The proposed method is sustained by our earlier work on differently configured carbon structures produced by condensing carbon from vapor phase. Our goal is to provide a better-controlled, straightforward and low-cost method for generating large quantities of fullerene-containing carbon soot. A key feature of the vaporisation apparatus is that it is a combination between arc discharge and plasma jet dissociation. The vaporisation of the carbon rod is not driven by ohmic heating but rather by a discharge between the end of graphite rod and the cathode of the plasma-jet system. There are several attractive features of this procedure. First, variations in the parameters of plasma jet may be used to control systematically the size distribution of fullerene clusters. Secondly, this could be used for solid studies of larger fullerenes clusters since large clusters are only produced in low yield by the arc-discharge method. Also, we believe that there is great potential to investigate systematic doping of fullerene cluster using this technique since dopants can be easly introduced into the plasma jet prior to thermal dissociation.     

Soot and other Products Formation from the Submerged Carbon Arc in Halogenated Solvents

A series of selected halomethanes were treated with the submerged carbon arc using graphite electrodes at 10A. CCl₄ and CHCl₃ produce abundant soot which is double in comparison to the soot produced by arcing CH₂Cl₂ and is one order of magnitude higher than the amount of soot produced by arcing hydrocarbons such as n-hexane or decalin and two orders of magnitudes higher in comparison to the amounts of soot produced by arcing alcohols. It was found a anticorrelation between the amount of polyynes present in the solution of the arced solvent and the amount of soot produced by arcing. In the case of CCl₄ and CHCl₃ no polyynes were detected by liquid chromatographic analysis (HPLC-DAD), while polyynes were detected in CH₂Cl₂ and are present in higher concentration in arced hydrocarbon solutions. The soot produced from halomethanes was analyzed by FT-IR spectroscopy in comparison to the soot produced by arcing hydrocarbons and alcohols. Furthermore, the soot from halomethanes was analyzed by HPLC-DAD after extraction with acetonitrile and found to contain a mixture of halogenated polycyclic aromatic hydrocarbons (PAHs). Also CHClBr and CH₂I₂ were arced between graphite electrodes. The former compound produces free bromine and soot; bromine causes halogenation of the polyynes. In the case of the latter compound, free iodine is released from the arc and the amount of soot produced is comparable to that obtained by arcing CH₂Cl₂.     

石墨镶嵌Co纳米晶的形成及其特性

用直流碳弧法在阳极石墨棒中加入金属Ｃｏ产生石墨镶嵌Ｃｏ纳米晶,研究在复合石墨棒中加入不同的Ｃｏ含量对石墨镶嵌Ｃｏ纳米晶的形貌、结构特性及晶粒尺寸分布的影响,探讨石墨镶嵌Ｃｏ纳米晶的形成原因及碳弧法中氦气压力和Ｃｏ含量对掺Ｃｏ阳极石墨棒所产生的碳灰的Ｃ６０／７０产率的影响。结果表明,复合阳极棒中的Ｃｏ含量决定了石墨镶嵌Ｃｏ纳米晶的数量和晶凿直径分布,碳弧法中的Ｈｅ气压力仍是影响掺Ｃｏ阳极棒所产生的碳