Tachypnea - Distinction from other breathing terms. 1  Different sources produce different classifications for breathing terms. 2  Some describe tachypnea as any rapid breathing. Hyperventilation is then described as increased ventilation of the alveoli (which can occur through increased rate or depth of breathing, or both) where there is a smaller rise in metabolic carbon dioxide relative to this increase in ventilation.
However, guidance is also possible, e.g., by the use of reflections, e.g. at metallic interfaces. Some waveguides also involve plasmonic effects at metals. Figure 1: Two different kinds of waveguides. Planar waveguides guide light only in the vertical direction, whereas channel waveguides guide in two dimensions.
The form of any wave (matter or electromagnetic) is determined by its source and described by the. shape of its wavefront, i.e., the locus of points of constant phase. If a traveling wave is emitted by. a planar source, then the points of constant phase form a plane surface parallel to the face of the. source. Such a wave is called a plane wave, and travels in one direction (ideally). Since energy is. conserved, the total energy in the wave must equal the energy emitted by the source, and therefore. the energy density (the energy passing through a unit area), is constant for a plane wave.