Accumulation period

An accumulation period (synthesis of organic building blocks),... 

In the experimental analysis the SW potential scan is preceded by a certain delay period (/delay) to allow the reactant to adsorb on the electrode surface. Besides, the reactant adsorbs additionally in the course of the voltammetric scan starting from the initial (Es) to the peak potential (fp). Thus, the total accumulation period (face)... 

Also bioaccumulating substances may in some situations call for a higher assessment factor. If accumulation is likely, the toxicity studies need to be of sufficient length to cover the accumulation period (e.g., the time to reach a steady-state concentration). If there is limited information on these aspects, it has to be considered to which extent this lack of information should affect the assessment factor. 

Apparatus for parallel-in to serial-out conversion is shown in GB-A-2007909. According to this invention a stationary image is focussed on the detector and a standing distribution of ambipolar carriers is allowed to accumulate. After an accumulation period a pulsed bias current is applied to sweep the carriers to the read-out region. 

Before beginning studies of inIn-eosinophil accumulation, it is recommended that the circulating mIn-eosinophils and %mIn free in the plasma are measured as a function of time. Circulating mIn-eosinophils will decrease because of clearance mechanisms and % free label will increase with time. We have found that a 2 1 h accumulation period gives satisfactory results. 

After an appropriate eosinophil accumulation period, kill the animals by C02-induced asphyxia. Remove, clean, and excise the skin injection sites, as described in Subheading 3.2.3., and freeze at -80°C. 

Adsorptive accumulation — Organic substances which exhibit -> surface activity and electroactivity can be electrochemically analyzed by adsorptive accumulation on the surface of a an electrode, e.g., mercury electrode, followed by the reduction, or oxidation of the adsorbate using -> voltammetry [i,ii]. Also, the adsorption of highly stable and inert -> complexes of metal ions with surface-active organic ligands is utilized for the determination of trace metals [iii]. In all these methods the maximum voltammetric response is linearly proportional to the surface concentration of the adsorbed analyte at the end of the accumulation period [iv]. In the majority of cases, the adsorption on mercury can be described by the -> Frumkin isotherm /icx=o = 0exp(ad)/(1- 9), where f is the adsorption constant, cx=o is the concentration of the dissolved compound at the electrode surface, 6 = T/rmax is the surface coverage, T is the surface concentration of the adsorbed compound, rmax is the maximum surface concentration and a is the Frumkin... 

Presence and Absence of Particles. Turnover of Co and Cs in Mya arenaria were measured by following both the accumulation and loss of radionuclides. However, the conditions under which the accumulation were measured differed from those of loss. During the accumulation period, the animals were maintained in filtered water in a closed system, whereas during the loss period, they... 

A chronopotentiometric method for determination of amino derivatives of PAH is based on the high affinity of DNA for such compounds. In a cell consisting of a DNA-modified CPE, a reference SSCE and a Pt wire auxiliary electrode, an aqueous solution of the PAA is submitted to an accumulation period, during which the analytes are transferred to the working electrode by an intercalation mechanism, after which the solution is changed... 

Solid scintillators such as anthracene have been tested as alternatives for continuous measurements (ICRU 1972). The scintillation material and the radionuclide collector are combined, as discussed above for scintillation beads (Winn 1993). The operating characteristics of these devices, such as the sample volume, count accumulation period, energy resolution, detection efficiency, and background must be arranged to satisfy radionuclide concentration limit specifications. 

Figure 6.15 The computer simulalion results of the heat-up process in Figure 6.14 (left). The temporal changes of various parameters near t = 0 are shown in the right plots. The symbols and notations are the same as those in Figure 6.12 except for the shaded area with the vertical stripes, which indicates the accumulation period.

The trust will tend to reduce in size as principal payments are received on the mortgages, and this principal can be used in one of three ways. Outside an accumulation period and when there are no amortising notes being redeemed, the principal receipts will be paid to the seller. In an accumula-... 

The master trust structure gives originators a high degree of flexibility over the redemption profiles of the notes they can create. The emphasis has understandably been on creating bullet securities in order to attract investors who would prefer to invest in securities with traditional bullet redemption profiles and short legal maturities. There have also been notes with a scheduled redemption profile issued from master trust structures and, in practice, the redemption profiles that can be created will only be limited by the size of the trust, the length of the required accumulation period, and any other note redemptions that are due from the same trust. 

Adsorptive stripping (AdSV) can be employed in the trace analysis of a wide variety of organic compounds exhibiting surface active properties. When the given compound contains an electrochemically reducible or oxidizable group, the peak current on the voltammetric curve recorded after completion of the accumulation period then corresponds practically only to the reduction or oxidation of the whole amount of the adsorbed electroactive species. Only tensammetric adsorption/desorption peaks are obtained for electroinactive compounds. 

Figure 2. Time course of PChlide and Mg-PPIXME disappearance from ALA plus DP-treated cucumber seedlings in daylight after a 17-h accumulation period.

The time distribution of the x-ray photons incident on the detector in an x-ray fluorescence spectrometer is described by Poisson statistics, providing that the half-life of the radioisotope excitation source is long compared to the data accumulation period, or providing that the x-ray tube output is truly constant. This means that both the x-ray tube current and voltage must be constant, with negligible drift or line frequency ripple. The arrival of photons at the detector is random in time as illustrated in Fig. 4.40. 

Figure 1 Typical stripping chronopotentiogram obtained from PSA. After an initial accumulation period, tec, at potential, Eacc. potentiostatic control of the electrochemical cell is discontinued and change in potential is plotted versus time.

Since the absolute amount of analyte accumulated during the preconcentration process is small the concentration of oxidant(s) in solution is assumed to be constant during the stripping process. The ratio [6] dstrip/ aco which is assumed to be between 5 and 10 under normal experimental conditions, can be kept constant by keeping the stirring rate during each accumulation period constant between experiments. 

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