Noise-power spectrum

Fig. 8. Noise power spectra commonly found in chemical instrumentation. (A) white"...

Fig. 9. Noise power spectra for ICP-OES using a Fassel-type torch, (a) 0-500 Hz and (b) 0-24 Hz sample 10000 pg/mLAI solution power 1.8 kW, outer gas 18 L/min Ar nebulizer pressure 3 bar Ar sample uptake rate 1 mL/min. (Reprinted with permission from Ref. [37].)...

In plasma mass spectrometry noise power spectra were also found to reflect the... 

Fig. 13. Noise power spectra in ICP-MS for ArO+ (56 dalton). Meinhard nebulizer, power 1350 W, outer gas 14 L/min, intermediate gas 1.4 L/min, nebulizer gas 1.0 L/min, sample uptake rate 1.05 mL/min, doubly distilled water. (Reprinted with permission from Ref. [41].)...

POLLMANN D., PlLGER C., Hergenroder R., Leis F., Tschopel P. and Broekaert J. A. C. (1994) Noise power spectra of inductively coupled plasma mass spectrometry using a cooled spray chamber, Spectrochim Acta, Part B 49 683-690. 

Belchamber R. M. and Horlick G. (1982) Noise power spectra of optical and acoustic emission signals from an ICP, Spectrochim Acta, Part B 37 17— 27. 

M.E. Green and M. Yafuso, A study of the noise generated during ion transport across membranes, J. Phys. Chem., 1968, 72, 4072-4078 I. Rubinstein. Mechanism for an electrodiffusional instability in concentration polarization, J. Chem. Soc., Faraday Trans. 2. 1981, 77, 1595-1609 F. Maletzki, H.-W. Rosier and E. Staude, Ion transport across electrodialysis membranes in the overlimiting current density range Stationary voltage current characteristics and current noise power spectra under different conditions of free convection, J. Membr. Sci., 1992, 71, 105-115. 

To check vdiether the system is operating at a dose level at vdiich quantum noise is the largest component, the response function can be used to translate typical pixel values (in the unprocessed image) to a detector dose level. It is also possible to evaluate the noise components in the frequency domain using the Noise Power Spectra. However, these results are more difficult to interpret and for QC purposes the analysis in the spatial domain is sufficient (Ravaglia et al. 2009). 

Instead of sending the two original images for analysis to a remote centre for quality supervision, a smaller package of data is sent, which includes the SNR in a specific ROI, the thumbnail images, a selection of DICOM header tags (for DR systems) or manual input such as anode/filter combination, peak tube voltage and tube current for CR with incomplete DICOM headers, a few line profiles and noise power spectra of six specific ROIs. 

F. 8. Noise power spectra commonly found in chemical instrumentation. (A) "white noise (B) flicker (1//) noise and (C) interference noise. (Reprinted with permission from Ref [36].)... 

Noise power spectra of inductively coupled plasma mass spectrometry using a cooled spray chamber,... 

Figure 53a displays typical noise power spectra of the Euq 4QSrp spin glass at two different temperatures above and below T = 1.54 K, compared to the noise of the detection system alone (Reim et al. 1986). While the empty-system noise is white above 1 Hz and shows some 1/tv component below 1 Hz, the noise level of the sample is up to three orders of magnitude larger and displays a 1/tv" behavior... 

Fig. 54. Logarithmic slope of the noise power spectra (from fig. 53) versus temperature near T, at five different frequencies. The solid curves show polynomial fits as guides for the eyes (from Reim et al. 1986).

Fig. 10. Noise power spectra and precision in ICP-OES for the introduction of (a) a 10000 pg/mL Al solution,...

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... 

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