Tailored especially for the working health professional, Radio Frequency and ELF Electrogmagnetic Energies is a practical guide to understanding, evaluating, and controlling the human health effects of radio-frequency (RF) and extremely low frequency (ELF) electromagnetic fields. Providing a perfect blend of applied information and theory, you'll find all you need to know about radiation safety, from the basic physics to how to set up a safety program. This book brings you cutting-edge discussions of exposure limits, monitoring instrumentation, new measurements required by human exposure standards, induced currents and contact currents, and the latest data on biological effects.
The linear theory of oscillations traditionally operates with frequency representa tions based on the concepts of a transfer function and a frequency response. The universality of the critria of Nyquist and Mikhailov and the simplicity and obvi ousness of the application of frequency and amplitude - frequency characteristics in analysing forced linear oscillations greatly encouraged the development of practi cally important nonlinear theories based on various forms of the harmonic balance hypothesis . Therefore mathematically rigorous frequency methods of investi gating nonlinear systems, which appeared in the 60s, also began to influence many areas of nonlinear theory of oscillations. First in this sphere of influence was a wide range of problems connected with multidimensional analogues of the famous van der Pol equation describing auto oscillations of generators of various radiotechnical devices. Such analogues have as a rule a unique unstable stationary point in the phase space and are Levinson dis sipative. One of the pioneering works in this field, which started the investigation of a three-dimensional analogue of the van der Pol equation, was K. O. Friedrichs's paper . The author suggested a scheme for constructing a positively invariant set homeomorphic to a torus, by means of which the existence of non-trivial periodic solutions was established. That scheme was then developed and improved for dif ferent classes of multidimensional dynamical systems [131, 132, 297, 317, 334, 357, 358]. The method of Poincare mapping [12, 13, 17] in piecewise linear systems was another intensively developed direction.
Due to the explosive global growth in the number of mobile subscribers, as well as the growth predicted in the mobile data segment, the need for improved spectrum efficiency on the radio interface becomes more and more important. Frequency hopping (FH) is an effective method for improving the spectrum efficiency. One of the advantages of FH is that it can be combined with other spectral efficiency improving features like power control, handover and reuse partitioning.
1. 1. Short History of Solar Radio Astronomy Since its birth in the forties of our century, solar radio astronomy has grown into an extensive scientific branch comprising a number of quite different topics covering technical sciences, astrophysics, plasma physics, solar-terrestrial physics, and other disciplines. Historically, the story of radio astronomy goes back to the times of James Clerk Maxwell, whose well known phenomenological electromagnetic field equations have become the basis of present-time radio physics. As a direct consequence of these equations, Maxwell was able to prognosticate the existence of radio waves which fifteen years later were experimentally detected by the famous work of Heinrich Hertz (1887/88). However, all attempts to detect radio waves from cosmic objects failed until 1932, which was mainly due to the early stage of development of receiving techniques and the as yet missing knowledge of the existence of a screening ionosphere (which was detected in 1925). Therefore, famous inventors like Thomas Edison and A. E. Kennelly, as well as Sir Oliver Lodge, were unsuccessful in receiving any radio emission from the Sun or other extraterrestrial sources. Another hindering point was that nobody could a priori expect that solar radio emission should have something to do with solar activity so that unfortunately by chance some experiments were carried out just at periods of low solar activity. This was also why Karl Guthe Jansky at the birth of radio astronomy detected galactic radio waves but no emission from the Sun.
A Frequency Dictionary of Turkish enables students of all levels to build on their study of Turkish in an efficient and engaging way.
Based on a 50 million word corpus, A Frequency Dictionary of Turkish provides a list of core vocabulary for learners of Turkish as a second or foreign language. It gives the most updated, reliable frequency guidelines for common vocabulary in spoken and written Turkish. Each of the 5000 entries are supported by detailed information including the English equivalent, an illustrative example with English translation and usage statistics.
The Dictionary provides a rich resource for language teaching and curriculum design, while a separate CD version provides the full text in a tab-delimited format ideally suited for use by corpus and computational linguists.
With entries arranged both by frequency and alphabetically, A Frequency Dictionary of Turkishenables students of all levels to get the most out of their study of vocabulary in an engaging and efficient way.