Say Hello, Wave Goodbye
Say Hello, Wave Goodbye
Say Hello, Wave Goodbye is an EP by Danish pop duo Junior Senior. Released in 2007, it is the duo's second EP release after Boy Meets Girl in 2003. It is their last release before their breakup in 2008. The EP was released with some repackages of the duo's second studio album, Hey Hey My My Yo Yo.
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Two in the Wave
Two in the Wave (French: Deux de la Vague) is a 2010 French documentary film directed by Emmanuel Laurent. The film depicts the friendship between French directors Franois Truffaut and Jean-Luc Godard.
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When describing light, what is meant by wave particle duality?
There are experiments where light will behave like a wave. Light can be measured to transmit energy and to oscillate at specific frequencies and wavelengths.There also experiments where light behaves like a particle, a photon, that has mass and momentum. No experiment has yet been devised where light behaves as both a particle and a wave.Light cannot be one or the other, but it appears in experiments as such. It is not either, nor is it both
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Samsung Wave 723
The Samsung Wave 723, or Samsung S7230, was released in October, 2010, alongside the Samsung Wave 525 and Samsung Wave 533. It was marketed as a mid-range phone, and cost around €130 ($170).
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2007 European heat wave
The 2007 European heat wave affected most of Southern Europe and the Balkans. The phenomenon began affecting Italy and Turkey on 17 June and expanded into Greece and the rest of the Balkans, Hungary and Ukraine on 18 June. The costs of the heat wave were estimated at 2 billion euros. .
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Ion acoustic wave
In plasma physics, an ion acoustic wave is one type of longitudinal oscillation of the ions and electrons in a plasma, much like acoustic waves traveling in neutral gas. However, because the waves propagate through positively charged ions, ion acoustic waves can interact with their electromagnetic fields, as well as simple collisions. In plasmas, ion acoustic waves are frequently referred to as acoustic waves or even just sound waves. They commonly govern the evolution of mass density, for instance due to pressure gradients, on time scales longer than the frequency corresponding to the relevant length scale. Ion acoustic waves can occur in an unmagnetized plasma or in a magnetized plasma parallel to the magnetic field. For a single ion species plasma and in the long wavelength limit, the waves are dispersionless ( ω = v s k displaystyle omega =v_sk ) with a speed given by (see derivation below) v s = γ e Z K B T e γ i K B T i M displaystyle v_s=sqrt frac gamma _eZK_BT_egamma _iK_BT_iM where K B displaystyle K_B is Boltzmann's constant, M displaystyle M is the mass of the ion, Z displaystyle Z is its charge, T e displaystyle T_e is the temperature of the electrons and T i displaystyle T_i is the temperature of the ions. Normally γe is taken to be unity, on the grounds that the thermal conductivity of electrons is large enough to keep them isothermal on the time scale of ion acoustic waves, and γi is taken to be 3, corresponding to one-dimensional motion. In collisionless plasmas, the electrons are often much hotter than the ions, in which case the second term in the numerator can be ignored.
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Bloch wave
A Bloch wave (also called Bloch state or Bloch function or Bloch wavefunction), named after Swiss physicist Felix Bloch, is a kind of wave function which can be written as a plane wave modulated by a periodic function. By definition, if a wave is a Bloch wave, its wavefunction can be written in the form: where r displaystyle mathbf r is position, displaystyle psi is the Bloch wave, u displaystyle u is a periodic function with the same periodicity as the crystal, the wave vector k displaystyle mathbf k is the crystal momentum vector, e displaystyle mathrm e is Euler's number, and i displaystyle mathrm i is the imaginary unit. Bloch waves are important in solid-state physics, where they are often used to describe an electron in a crystal. This application is motivated by Bloch's theorem, which states that the energy eigenstates for an electron in a crystal can be written as Bloch waves (more precisely, it states that the electron wave functions in a crystal have a basis consisting entirely of Bloch wave energy eigenstates). This fact underlies the concept of electronic band structures. These Bloch wave energy eigenstates are written with subscripts as n k displaystyle psi _nmathbf k , where n displaystyle n is a discrete index, called the band index, which is present because there are many different Bloch waves with the same k displaystyle mathbf k (each has a different periodic component u displaystyle u ). Within a band (i.e., for fixed n displaystyle n ), n k displaystyle psi _nmathbf k varies continuously with k displaystyle mathbf k , as does its energy. Also, for any reciprocal lattice vector K displaystyle mathbf K , n k = n ( k K ) displaystyle psi _nmathbf k =psi _n(mathbf kK ) . Therefore, all distinct Bloch waves occur for values of k displaystyle mathbf k which fall within the first Brillouin zone of the reciprocal lattice.
