Gas flow dynamic

R. W. Mair, R. L. Walsworth 2005, (Study of gas-fluidization dynamics with laser-polarized 129Xe), Magn. Reson. /mag. 23, 203-207 (b) R. Wang 2005, (Study of gas flow dynamics in porous and granular media with laser-polarized 129Xe NMR), Ph.D. Thesis, Department of Nuclear Engineering, Massachusetts Institute of Technology, February 2005. 

Chemical vapor deposition is a very complex process. There are numerous factors such as type, shape, and size of reactor, gas flow rate and arrangement that can affect the properties of the coating. Therefore, it is necessary to review briefly the process itself which includes reactor, reaction zones, temperature, pressure, precursors, and gas flow dynamics before discussing the thermodynamics and kinetics of the CVD. 

In situ adsorption cells enable adsorption under gas flow (dynamic mode) or under pressure (static mode). The catalysts are generally studied afler pre-treatment, under specific gases or under secondary vacuum, at high temperature. Adsorption may be carried out between 450 C and liquid nitrogen temperature depending on the material used. 

In the case of a toroidal microwave discharge obtained in a microwave plasma torch, the frequency dependent noise stemming from the gas flow dynamics could also be found at a frequency of 150-250 Hz (Fig. 11) [39]. When using hydride... 

However, as shown in the noise spectra (Fig. 9), there is a frequency dependent component at about 200 Hz, this being due to the gas flow dynamics, as has been mentioned by Belchamber and Horlick [400], The flicker noise present increases when particles are entering the ICP that can no longer be completely evaporated. This is e.g. the case when blowing powders into the ICP. 

GAS FLOW - DYNAMIC MEASUREMENT PISTON-TYPE PROVER... 

In a noise spectrum (Fig. 5) the noise amplitude is plotted as a function of frequency [31]. White noise (Fig. 5 A) occurs over all frequencies and is almost always fundamental in origin, whereas for Mf noise (Fig. 5B) the amplitude decreases with the frequency and it is nonfundamental in origin. Discrete noise bands with well-defined causes may also occur (Fig. 5 C). These may stem from the source, caused by gas flow dynamics or contributions from the vacuum line, etc. Noise spectra are a powerful diagnostic tool to trace the sources of noise, and to study instrumental limitations to the power of detection. In atomic. spectrometry, it is important to determine if noise from the detector is predominant if so. it can be described by a Poisson distribution ... 

In plasma mass spectrometry, noise power spectra were also found to reflect the gas flows dynamics (Fig. 13) [41]. However, in ICP-MS they also were found to be severely influenced by the cooling of the spray chamber. This is understandable as this will influence the droplet evaporation during aerosol transport as well as the... 

Figure 6.6 Visualization of gas flow dynamics in the ablation cell using materials of different particle size diameter. (Reproduced from reference 12, with permission of The Royal Society of Chemistry.)...

---