Radio Frequency source

The sample is taken in a glass tube which is placed between pole faces of a magnet. A radio frequency source (v = 60 mega cycles sec ) is made to fall on the sample. It is done by feeding... 

Interestingly, the precessing proton can only absorb energy from the radio frequency source if the precessing frequency is exactly the same as that of the radio frequency beam and when this particular situation arises, the nucleus and the radio frequency beam are said to be in resonance, thereby justifying the term nuclear magnetic resonance . 

When fired electrically, fireworks are connected to wirebridge fuseheads. The fuseheads can inadvertently ignite if subjected to radio hazard (RAD HAZ) when in the vicinity of radio frequency sources such as cellular (mobile) telephones or walkie-talkie radios. Further advice on this should be sought from the makers of the wirebridge fuseheads and of the communication equipment because the characteristics of all these items can vary to some extent. 

Figure 1. Polymerization reactor (1 m long and 75 mm in diameter) (M) leads to monomer mixing system and (P) to pumps (O) is a 75 O-ring joint (A) and (B) are 24/40 ground glass joints, (A) connects to a secondary inlet system and (B) to a pressure guage and, (RF) is the 27.1 MHz radio frequency source.

To this list can be added various major specialized sub-systems that are required for some of the more sophisticated experiments. Some of the basic sub-systems also require modification for these experiments. (7) Pulse programmer for time domain ESR (8) programmable radio frequency source for electron-nuclear double resonance (ENDOR) (9) pump microwave source for electron-electron double resonance (ELDOR). 

High resolution NMR spectrometers can be categorized into continuous wave (CW) and pulsed FT, both of them requiring a radio-frequency source and a magnetic field. As... 

The simultaneous application of a strong external magnetic field Ho, and the radiation from a second and weaker radio-frequency source Hi (applied perpendicular to Hg) to the nuclei results in transitions between energy states of the nuclear spin. The NMR phenomenon occurs when these nuclei undergo transition from one alignment in the applied field to an opposite one. This process is illustrated in Fig. 14 for a hydrogen nucleus. 

Equipment found in laboratories that can produce hazardous amounts of electromagnetic radiation includes ultraviolet lamps, arc lamps, heat lamps, lasers, microwave and radio-frequency sources, and x-rays and electron beams. 

FIGURE 22.5 Electromagnetic frequency spectrum (a) to light and beyond, (b) selected radio frequencies. Source-1996 Hammett Edison, Inc. With permission.)... 

Figure 5.8(a)). Some recently developed visible-deuterium lamps (see Figure 5.8(b)) are powered by radio frequency sources and can operate in a flashing mode, which saves energy and stabilization time. In addition, they use voltages low enough to be used in held measurements. 

EDLs are available commercially for fifteen or more elements. Their performance is not as reliable as that of the hollow-cathode lamp, but for elements such as Se, As, Cd. and Sb, EDLs exhibit better detection limits than do hollow-cathode lamps. This occurs because EDLs for these elements are more intense than the corresponding hollow-cathode lamps, and thus, EDLs are quite useful in determining these elements. Figure 9-12 is a schematic of a commercial EDL, which is powered by a 27-MHz radio-frequency source. 

Radio Frequency Sources RF sources, also referred to as RF antenna sources, have found recent application in Dynamic SIMS (Smith et al. 

Figure 4.6 Simplified schematic illustration of a typical Radio Frequency source.

AE = energy absorbed from the radio-frequency source which will induce transitions between the two states of the electron h = Planck s constant ... 

Radio frequency sources are sources where rf energy is directly inductively coupled into an electrical conductor such as metals or carbon. The rf can be used to heat the source material directly or to heat the container ( susceptor ) that holds the source material. This technique has been particularly useful in evaporating aluminum from BN and BN/TiB2 crucibles. 

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