Flicker-noise

Intermlttency Manneville [mann80] showed that for the special case of a generic intermittency threshold in which the tangent point lies at the endpoint of the interval (in the case of a one dimensional iterative map of an interval to itself), the resulting chaotic dynamics has a power spectrum S f) 1/ (/(log/) ) for low /. Miracky, et. al. were able to modify the map to obtain an exact 1// behavior [mirack87]. Because the result depends on the fine-tuning of an external parameter, however, it does not so mucdi explain the generic appearance of flicker noise phenomena as beg the obvious question, why do systems typically sit at whatever... 

Because process mixtures are complex, specialized detectors may substitute for separation efficiency. One specialized detector is the array amperometric detector, which allows selective detection of electrochemically active compounds.23 Electrochemical array detectors are discussed in greater detail in Chapter 5. Many pharmaceutical compounds are chiral, so a detector capable of determining optical purity would be extremely useful in monitoring synthetic reactions. A double-beam circular dichroism detector using a laser as the source was used for the selective detection of chiral cobalt compounds.24 The double-beam, single-source construction reduces the limitations of flicker noise. Chemiluminescence of an ozonized mixture was used as the principle for a sulfur-selective detector used to analyze pesticides, proteins, and blood thiols from rat plasma.25 Chemiluminescence using bis (2,4, 6-trichlorophenyl) oxalate was used for the selective detection of catalytically reduced nitrated polycyclic aromatic hydrocarbons from diesel exhaust.26... 

As usual, we will continue in the next chapter we will now start on the derivations of formulas relating to the effects of what we have previously called scintillation noise , and which is also called flicker noise , source noise , and other labels. Basically this... 

Therefore the flicker noise is expected to grow with 7 as the device size is scaled down. In deep submicron MOSFETs the corner frequency at which thermal noise equals flicker noise may be as large as 100 MHz, indicating that, at low frequency, 1/f noise is the most severe noise source which affects sensor performance. 

Flexural modulus, 10 177, 223, 224 of filled polymers, 11 303 Flexure strength, of silicon carbide, 22 528t FLExX, 6 13 FlexX method, 10 337 Flicker noise, silicon-based semiconductors and, 22 237 Flint, 5 640 22 480... 

A completely new design of ROA instrument with significant advantages inherent to the SCP strategy has recently been developed by Hug [19, 25]. This strategy cancels out the flicker noise arising from dust particles and... 

Photon shot-noise or preamplifier shot-noise limitations, or source-flicker-noise limitations but utilizing source compensation" techniques... 

Source compensation Pulse-to-pulse intensity variations and intensity fluctuations in the spectrometric excitation source are often the dominant noise source affecting the performance of the detection system. However, since OIDs are parallel multichannel detectors, these intensityvariations do equally and simultaneously affect the entire spectral distribution as a whole. Thus, with the aid of a single-channel reference detector, monitoring a portion of the source s light flux, it is possible to accurately normalize for spectrum-to-spectrum variations and practically eliminate these and any other source flicker noise related effects. 

Sometimes, 1//noise is called flicker noise and is allowed a distribution function... 

Flicker-noise spectroscopy — The spectral density of - flicker noise (also known as 1// noise, excess noise, semiconductor noise, low-frequency noise, contact noise, and pink noise) increases with frequency. Flicker noise spectroscopy (FNS) is a relatively new method based on the representation of a nonstationary chaotic signal as a sequence of irregularities (such as spikes, jumps, and discontinuities of derivatives of various orders) that conveys information about the time dynamics of the signal [i—iii]. This is accomplished by analysis of the power spectra and the moments of different orders of the signal. The FNS approach is based on the ideas of deterministic chaos and maybe used to identify any chaotic nonstationary signal. Thus, FNS has application to electrochemical systems (-> noise analysis). 

Refs. [i] Timashev SF (1993) Zh Fiz Khim 67 1755 [ii] Timashev SF (2001) Russ J Phys Chem 75 1742 [Hi] Timashev SF (2001) Flicker-noise spectroscopy as a tool for analysis of fluctuations in physical systems. In Bosman G (ed) Noise in physical systems and 1/f fluctuations. ICNF, World Scientific, New Jersey, pp 775-778 [iv] Timashev SF, Vstovskii GV (2003) Russ JElectrochem 39 141 [v] Parkhutik V, Patil R, Harima Y, Matveyeva E (2006) Electrochim Acta 51 2656 [vi]Parkhutik V, RayonE, FerrerC, TimashevS, Vstovsky G (2003) Phys Status Solidi A Applied Research 197 471... 

FNS - flicker-noise spectroscopy Formal potential - potential Foerster, Fritz... 

Flicker noise — is common to all solid-state devices and predominates in measurements at frequencies, / < 300 Hz. Although the physical origin of this noise is not well understood, it can be described by the following empirical equation [/fiicker = (KI2If)1/2, [/flicker is the - root mean square amplitude of this noise, K is a constant depending on factors such as resistor materials and geometry, and I is the DC current [i]. 

Wavelet analysis is a rather new mathematical tool for the frequency analysis of nonstationary time series signals, such as ECN data. This approach simulates a complex time series by breaking up the ECN data into different frequency components or wave packets, yielding information on the amplitude of any periodic signals within the time series data and how this amplitude varies with time. This approach has been applied to the analysis of ECN data [v, vi]. Since electrochemical noise is 1/f (or flicker) noise, the new technique of -> flicker noise spectroscopy may also find increasing application. 

However, the disadvantages of optical rotation detectors may be limited by shot or flicker noise, which are dependent on the optical and mechanical properties of the system or by noise in the detector electronics. Generally, the usefulness of this technique has been limited by the lack of sensitivity of commercially available instruments. 

Flicker noise is commonly defined classically for absorption and emission spectroscopy (see Ref. 1, pp. 144-145) but also applies to Raman spectroscopy. Variation in laser intensity at both low and high frequencies will... 

Spectrometer designs vary in their sensitivity to flicker noise as will be discussed in Chapters 8 and 9. For example, a multichannel spectrometer is fairly immune to flicker noise because all wavelengths are monitored in parallel, while a scanning system is very sensitive to flicker noise depending on the flicker frequency. Interferometers used in FT-Raman are sensitive to flicker noise when the sampling frequency is comparable to the flicker frequncy. 

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