Physical Concept

Here we expand upon the terms explained briefly in the Glossary. 

The instrument AMS, first on the Space Shuttle, and then the International Space Station, will search for antimatter particles. 

The total particle spectrum spectmm is about below the knee and about above the knee, at 5 PeV, and flattens again to about beyond the ankle, at about 3 EeV. Electrons have a spectrum which is similar to that of protons below about 10 GeV, and steeper near above this energy. The lower energy spectrum of electrons is inferred from radio emission, while the steeper spectrum at the higher energies is measured directly (Fig. 1). 

The fraction of antiparticles, ie., positrons and antiprotons, is a few percent for the positron fraction and a few 10 for antiprotons. No other antinuclei have been found (Figs. 3-5). 

There is no significant anisotropy of cosmic rays at any energy, not even at the highest energies, beyond the GZK cutoff. Only at those highest energies is there a persistent hint that events at quite different energies occasionally cluster into pairs and triplets in the sky in the arrival direction, and this is hard to understand in almost any model. 

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Sohmidt R, Lutz FI O and Dreizier R (eds) 1992 Nuclear Physics Concepts in the Study of Atomic Cluster Physics (Berlin Springer)... 

We have tried to present the material in an uncomplicated way, and to make the examples entertaining, while establishing basic physical concepts and their application to materials processing. We found that the best way to do this was to identify a small set of "generic" materials of each class (of metals, of ceramics, etc.) which broadly typified the class, and to base the development on these they provide the pegs on which the discussion and examples are hung. But the lecturer who wishes to draw other materials into the discussion should not find this difficult. 

ERDA, like RBS, is based on the following physical concepts ... 

The analysis of the consequences of nuclear accidents began with physical concepts of core melt, discussed the mathematical and code models of radionuclide release and transport within the plant to its release into the environment, models for atmospheric transport and the calculation of health effects in humans. After the probabilities and consequences of the accidents have been determined, they must be assembled and the results studied and presented to convey the meanings. 

The duality of the piot in Figure 1-24 is important. That is, stiffness is often equally important and sometimes even more important than strength. Some people tend to say strength when they actually a iean stiffness. We must carefully and completely distinguish between these two very different physical concepts. 

Today, a large number of researchers from a variety of fields are enthusiastically working on CNTs. Field emission has a relatively long history and has proceeded considerably, while the investigation into nanodevices has just begun. Some of research only involves the replacement the well-established material by CNTs. It is, however, more exciting to find out the new physical concepts through research of this novel material, CNTs. 

In the first chapter several traditional types of physical models were discussed. These models rely on the physical concepts of energies and forces to guide the actions of molecules or other species, and are customarily expressed mathematically in terms of coupled sets of ordinary or partial differential equations. Most traditional models are deterministic in nature— that is, the results of simulations based on these models are completely determined by the force fields employed and the initial conditions of the simulations. In this chapter a very different approach is introduced, one in which the behaviors of the species under investigation are governed not by forces and energies, but by rules. The rules, as we shall see, can be either deterministic or probabilistic, the latter leading to important new insights and possibilities. This new approach relies on the use of cellular automata. 

The physical concept of a single electrode potential has been also discussed in terms of the energy levels of ions in electrode systems. This concept may be usefirl in the cases where the system has no electronic energy levels in a range of practical interest, such as in ionic solid crystalline and electronically nonconductive membrane electrodes. "... 

Appendix B Chemical and Physical Concepts LIQUID AND SOLID... 

Appendix B covers some relevant chemical and physical concepts used in the book. 

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