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430 results on '"Kroto, H. W."'

8. General Discussion after Session V

Author

Wickramasinghe, N. C., Porter, George, Lipschutz, M. E., Chang, S., Pellas, P., Wasserburg, G. J., McKay, D., Woolfson, M. M., Wallis, M. K., Lovell, Bernard, and Kroto, H. W.

Published
1988

10. General Discussion after Session I

Author

Williams, D. A., Clayton, D., Kroto, H. W., Fegley, B., Pillinger, C. T., Tayler, R. J., Chang, S., Wetherhill, G. W., Wolstencroft, R. D., Woolfson, M. M., Turner, G., and Pellas, P.

Published
1988

33. Condensed-phase nanotubes

Author

Hsu, W. K., Hare, J. P., Terrones, M., Kroto, H. W., Walton, D. R. M., and Harris, P. J. F.

Published
1995

34. The formation and structure of circumstellar and interstellar dust

Author

Kroto, H. W

Subjects
Astrophysics
Abstract

The intriguing abundance of long linear carbon chain molecules in some dark clouds and in circumstellar shells is still not well understood. Recent laboratory studies which have probed this problem indicate that when carbon vapor nucleates to form particles, linear chains and hollow cage molecules (fullerenes) also form at more-or-less the same time. The results have consequences for the formation, structures and spectroscopic properties of the molecular and dust components ejected from cool carbon-rich stars. A most interesting result of the experimental observations relates to the probability that a third character in addition to the chains and grains, the C(sub 60) molecule probably in the form of the ion C(sub 60)(sup +) in the less shielded regions, is present and perhaps responsible for some of the ubiquitously observed interstellar spectroscopic features such as the Diffuse Interstellar Features, the 2170A UV Absorption or perhaps some of the Unidentified Infrared Bands. Further study of small carbon particles which form in the gas phase has resulted in the discovery that they have quasi-icosahedral spiral shell structures. The role that such species may play in the interstellar medium as well as that played by C(sub 60) (or C sub 60 sup +) should soon be accessible to verification by a combination of laboratory experiment and astronomical spectroscopy.

Published
1990

35. Compartmentalized CN[sub x] nanotubes: Chemistry, morphology, and growth.

Author

Trasobares, S., Ste´phan, O., Colliex, C., Hsu, W. K., Kroto, H. W., and Walton, D. R. M.

Subjects
NANOTUBES, NITROGEN, CARBON
Abstract

A systematic study of the effect of different synthesis parameters on N incorporation into C nanotubes is presented. CN[sub x] nanotubes prepared by catalyzed pyrolysis of melamine exhibit a highly compartmentalized morphology with a remarkable periodicity structure along the nanotube axis. Spatially resolved electron energy loss spectroscopy (spectrum-imaging mode) indicates that the nanotubes are made of carbon and nitrogen, inhomogeneously distributed with an enrichment of carbon on the external surfaces. The evolution of the C-K-edge shape across the nanotube reveals a transition from a graphitic stacking on the outside to a disorganized-mixed type in the core of the nanotube. For the N-K edge, the situation is more complex. The fine structure of the N-K edge differs depending on the used catalyst, which indicates differences in the bonding configuration. When Ni is used as a catalyst, N replaces C in the graphitic structure whereas C–N pyridinic-like bonds are formed when the catalyst is Fe. The compartmentalized periodic morphology is the result of a systematic catalytic particle movement from the root of the nanotube to the tip. This displacement is defined by the nature of the catalytic particle, diffusion, and supersaturation (C/N) in the liquid particle and precipitation process. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2002
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37. Fullerene Derivatives as Nano-Additives in Polymer Composites

Author

Penkova, A. V., Acquah, S. F. A., Piotrovskiy, L. B., Markelov, D., Semisalova, A., and Kroto, H. W.

Subjects
photovoltaic, antioxidant, Fullerene, sensor, catalyst
Abstract

Since their discovery, fullerenes have become one of the most recognizable molecules in science. The “beautiful molecule” described by Sir Harold Kroto has been subtly referenced in movie, and has adorned the covers of many science-based textbooks. The physical and chemical properties of fullerenes have generated a lot of interest in the science community with many opportunities to develop new avenues for scientific research. However, the difficulties in the commercial use of fullerenes, such as C60, have likely been due to issues with solubility. Fortunately, the situation has improved over the last decade with research into fullerene derivatives. Once modified, fullerenes may have applications in a variety of areas, including medicine, drug delivery, optoelectronics, and electrochemistry. The addition of low concentrations of carbon nanoparticles to polymer matrices may result in significant changes in the function of polymer-based composite materials. This review will highlight the applications of fullerene derivatives as nano-additives for polymer composites. In this review, fullerene derivatives, such as water-soluble carbon nanoclusters (hydroxyl and carboxyl groups), and hydrophobic fullerenes, such as metallofullerenes and methanofullerenes, will be evaluated in regards to their potential impact on commercial applications, such as photovoltaic devices, fuel cells, membrane technology and biocompatible electroactive actuators.

Published
2017

40. Magnetic and Hysteretic Properties of Fe-Filled Nanotubes

Author

Prados, C., Crespo, P., Gonzalez, J. M., Hernando, A., Marco, J. F., Gancedo, R., Grobert, N., Terrones, M., Walton, R. M., and Kroto, H. W.

Subjects
Iron -- Analysis, Anisotropy -- Analysis, Spectrum analysis -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

The hysteretic properties of Fe-filled carbon nanotubes samples are presented and related to their magnetic phase distribution obtained by Massbauer spectroscopy. The most relevant result corresponds to the observation of a high anisotropy [Gamma]-Fe phase getting magnetically ordered at 100 K. Below this temperature, irreversibility in the high field zero field cooling (ZFC)-field cooling (FC) curves, as well as shifted hysteresis loops are observed. These results are explained in terms of the blocking of the high anisotropy phase and the development of exchange anisotropy. Index Terms--Carbon nanotubes, coercive field, exchange anisotropy, Fe nanowires.

Published
2001

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