دانلود کتاب Almost All About Waves

Among his peers, John R. Pierce is properly appreciated as a creator of complex engineering realities from the most basic of scientific insights. To those of more modest technical attainment, he can be directly valued as a teacher with a talent for making his concerns understandable to those willing to commit their interest and attention. In this book, he once again brings a diffuse and difficult subject within reach of nonspecialized readers. The book presents waves in all their manifestations and realizations, a subject that perfectly joins basic science and everyday reality. And it does so with what, nowadays, might be regarded as a modicum of mathematics, venturing just across the line of partial differential equations, which is where the wave equation is at home and emerges to be seen fully revealed. Pierce considers waves in the most general light as one of the great unifying concepts of physics. This approach will allow the reader to comprehend an almost unlimited array of specific phenomena: "Modern physics is full of waves," Pierce writes, "the earthquake waves which seismologists study; the waves and ripples on oceans, lakes, and ponds; the waves of sound which travel through the air; the mechanical waves in stretched strings and in the quartz crystals that are used to control the frequency of radio transmitters; the electromagnetic waves that constitute light, and that are radiated by radio transmitters and received by radio receivers; and finally, the waves of what?—probability, perhaps—which are used in quantum mechanics to predict the behavior of electrons, atoms, and complex substances." The emphasis is on behavior common to all these and other waves: what happens when waves interact with one another in waveguides and traveling-wave tubes; the behavior of waves in moving media; the directional patterns of complex sources; transmission between directive antennas; waves from bodies moving faster than the speed of waves in the medium and waves carried along by bodies moving more slowly than waves in the medium and the nature of plane and nearly plane waves. Among the concepts covered are phase velocity and group velocity, vector and complex representation, energy and momentum, coupled modes and coupling between modes, polarization, diffraction, and radiation.