Wave oscillating

EIOs), backward wave oscillators (BWOs) or magnetrons are available. Their spectral characteristics may be favourable however, they typically require highly stabilized high-voltage power supplies. Still higher frequencies may be obtained using far-infrared gas lasers pumped for example by a CO- laser [49]. 

In the microwave region tunable monochromatic radiation is produced by klystrons, each one being tunable over a relatively small frequency range, or a backward wave oscillator, tunable over a much larger range. Both are electronic devices. Absorption experiments are usually carried out in the gas phase, and mica windows, which transmit in this region, are placed on either end of the absorption cell, which may be several metres in length. Stark... 

Microwave Klystron backward wave oscillator Mica None Crystal diode... 

Millimetre wave Klyston (frequency multiplied) backward wave oscillator Mica polymer None Crystal diode Golay cell thermocouple bolometer pyroelectric... 

Millimetre wave radiation may also be generated by a klystron or backward wave oscillator but, since klystrons produce only microwave radiation, the frequency must be... 

Full-wave oscillations will not occur for values below Bs = 0.5 X 10-5... 

Plane-polarized light (Section 9.3) Ordinary light that has its electromagnetic waves oscillating in a single plane rather than in random planes. The plane of polarization is rotated when the light is passed through a solution of a chiral substance. 

The pressure spike introduces a disruption in the flow. Depending on the local conditions, the excess pressure inside the bubble may overcome the inertia of the incoming liquid and the pressure in the inlet manifold, and cause a reverse flow of varying intensity depending on the local conditions. There are two ways to reduce the flow instabilities reduce the local liquid superheat at the ONB and introduce a pressure drop element at the entrance of each channel, Kandlikar (2006). Kakac and Bon (2008) reported that density-wave oscillations were observed also in conventional size channels. Introduction of additional pressure drop at the inlet (small diameter orifices were employed for this purpose) stabilized the system. 

Density-wave oscillations Pressure drop oscillations Flow regime-induced instability... 

Lahey (1990) indicated the applications of fractal and chaos theory in the field of two-phase flow and heat transfer, especially during density wave oscillations in boiling flow. 

Yadigaroglu, G., and A. E. Bergles, 1969, An Experimental and Theoretical Study of Density-Wave Oscillation in Two-Phase Flow, M.I.T. Rep. DSR 74629-3 (HTL 74629-67), Massachusetts Institute of Technology, Cambridge, MA. (6)... 

Hz = Hertz, unit of frequency - the number of times a wave oscillates per unit time - measured in cycles per second. 

A family of vacuum-tube MMW sources is based on the propagation of an electron beam through a so-called slow-wave or periodic structure. Radiation propagates on the slow-wave structure at the speed of the electron beam, allowing the beam and radiation field to interact. Devices in this category are the traveling-wave tube (TWT), the backward-wave oscillator (BWO) and the extended interaction oscillator (EIO) klystron. TWTs are characterized by wide bandwidths and intermediate power output. These devices operate well at frequencies up to 100 GHz. BWOs, so called because the radiation within the vacuum tube travels in a direction opposite to that of the electron beam, have very wide bandwidths and low output powers. These sources operate at frequencies up to 1.3 THz and are extensively used in THZ spectroscopic applications [10] [11] [12]. The EIO is a high-power, narrow band tube that has an output power of 1 kW at 95 GHz and about 100 W at 230 GHz. It is available in both oscillator and amplifier, CW and pulsed versions. This source has been extensively used in MMW radar applications with some success [13]. 

Fig. 7. MR detection of ultrasonic waves oscillating at 515 kHz. (a) Phase image of a phantom without insonation. (b) Phase image with 40 W peak power insonation. In the NMR sequence 50,000 cycles of synchronized sine-shaped motion-sensitizing gradient were applied. Arrows indicate the null-gradient positions of the dedicated gradient coil system. Wavelength is around 2.9 mm and peak matter displacement is around 120 nm. From Ref. 30, reprinted by permission of Wiley-Liss, Inc., a subsidiary of John Wiley Sons, Inc.

A. Destexhe and T. J. Sejnowski, Interactions between membrane conductances underlying thalamocortical slow wave oscillations. Physiol. Rev 83, 1401-1453 (2(X)3). 

N) E.W. Price, "Recent Advances in Solid Propellant Combustion Instability , Ibid, pp 101-113 O) G.A. Marxman C.E. Wooldridge, "Finite-Amplitude Axial Instability in Solid-Rocket Combustion , Ibid, pp 115-27 P) W.A. Sirignano, "A Theory of Axial-Mode Shock-Wave Oscillations in a Solid-Rocket Combustor ,Ibid, pp 129-37 Q) B.T.Zinn C.T. Saveli, "A Theoretical Study of Three-Dimensional Combustion Instability in Liquid-Propellant Rocket Engines , Ibid, pp 139-47 R) R.J. Priem E.J. Rice, "Combustion Instability with Finite Mach Number Flow and Acoustic Liners , Ibid, pp 149-59 S) M.W. Thring, "Combustion Oscillations in Industrial Combustion Chambers , Ibid, pp 163-68... 

Sirignano, "A Theory of Axial-Mode Shock-Wave Oscillations in a Solid-Rocket Combustor , 12thSympCombstn (1968), pp 129-37... 

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