Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Exponential truncated

This prediction has been confirmed by the results of Refs. 123 and 124. In fact, the numerical result of Ref. 123 indicates that the waiting time distribution of Eq. (274) has an exponential truncation, this being an effect of the tunneling from the boundary between chaotic sea and accelerator island, back to the chaotic sea. The authors of Refs. 31 and 122 argue that the quantum induced recovery of ordinary diffusion is followed by a corresponding localization process. [Pg.444]

Defibrillators are also made as implanted types, using intracardial catheter electrodes. To reduce energy consumption, new waveforms have been taken into use the exponential truncated waveform. It may be monophasic or biphasic. The idea of the hiphasic waveform is that the second pulse shall cancel the net charge caused by the first pulse and thereby reduce the chance of refibrillation. [Pg.452]

The state-transition model can be analyzed using a number of approaches as a Markov chains, using semi-Markov processes or using Monte Carlo simulation (Fishman 1996). The applicability of each method depends on the assumptions that can be made regarding faults occurrence and a repair time. In case of the Markov approach, it is necessary to assume that both the faults and renewals occur with constant intensities (i.e. exponential distribution). Also the large number of states makes Markov or semi-Markov method more difficult to use. Presented in the previous section reliability model includes random values with exponential, truncated normal and discrete distributions as well as some periodic relations (staff working time), so it is hard to be solved by analytical methods. [Pg.2081]

It can be shown [ ] that the expansion of the exponential operators truncates exactly at the fourth power in T. As a result, the exact CC equations are quartic equations for the t y, etc amplitudes. The matrix elements... [Pg.2178]

This means that the discrete solution nearly conserves the Hamiltonian H and, thus, conserves H up to 0 t ). If H is analytic, then the truncation index N in (2) is arbitrary. In general, however, the above formal series diverges as jV —> 00. The term exponentially close may be specified by the following theorem. [Pg.101]

Theorem 1 ([8]). Let H be analytic. There exists some r > 0, so that for all T < Tt the numerical solution Xk = ) Xo and the exact solution x of the perturbed system H (the sum being truncated after N = 0 1/t) terms) with x(0) = Xq remain exponentially close in the sense that... [Pg.101]

In mathematics there is a large number of complete sets of one-particle functions given, and many of those may be convenient for physical applications. With the development of the modern electronic computers, there has been a trend to use such sets as render particularly simple matrix elements HKL of the energy, and the accuracy desired has then been obtained by choosing the truncated set larger and larger. Here we would like to mention the use of Gaussian wave functions (Boys 1950, Meckler 1953) and the use of the exponential radial set (Boys 1955), i.e., respectively... [Pg.276]

The stagnant region can be detected if the mean residence time is known independently, i.e., from Equation (1.41). Suppose we know that f=lh for this reactor and that we truncate the integration of Equation (15.13) after 5h. If the tank were well mixed (i.e., if W t) had an exponential distribution), the integration of Equation (15.13) out to 5f would give an observed t of... [Pg.554]

Fig. 39.15. Area under a plasma concentration curve AUC as the sum of a truncated and an extrapolated part. The former is obtained by numerical integration (e.g. trapezium rule) between times 0 and T, the latter is computed from the parameters of a least squares fit to the exponentially decaying part of the curve (P-phase). Fig. 39.15. Area under a plasma concentration curve AUC as the sum of a truncated and an extrapolated part. The former is obtained by numerical integration (e.g. trapezium rule) between times 0 and T, the latter is computed from the parameters of a least squares fit to the exponentially decaying part of the curve (P-phase).
Many other filter functions can be designed, e.g. an exponential or a trapezoidal function, or a band pass filter. As a rule exponential and trapezoidal filters perform better than cut-off filters, because an abrupt truncation of the Fourier coefficients may introduce artifacts, such as the annoying appearance of periodicities on the signal. The problem of choosing filter shapes is discussed in more detail by Lam and Isenhour [11] with references to a more thorough mathematical treatment of the subject. The expression for a band-pass filter is H v) = 1 for v j < v < else... [Pg.548]

So far in our revision of the Debye-Hiickel theory we have focused our attention on the truncation of Coulomb integrals due to hard sphere holes formed around the ions. The corresponding corrections have redefined the inverse Debye length k but not altered the exponential form of the charge density. Now we shall take note of the fact that the exponential form of the charge density cannot be maintained at high /c-values, since this would imply a negative coion density for small separations. Recall that in the linear theory for symmetrical primitive electrolyte models we have... [Pg.114]

The exact amount of error introduced cannot immediately be inferred from the strength of the amplitudes of the neglected Fourier coefficients, because errors will pile up in different points in the crystal depending on the structure factors phases as well to investigate the errors, a direct comparison can be made in real space between the MaxEnt map, and a map computed from exponentiation of a resolution-truncated perfect m -map, whose Fourier coefficients are known up to any order by analysing log(<7 (x) tm (x)). [Pg.20]

Sometimes the FID doesn t behave as we would like. If we have a truncated FID, Fourier transformation (see Section 4.4) will give rise to some artefacts in the spectrum. This is because the truncation will appear to have some square wave character to it and the Fourier transform of this gives rise to a Sine function (as described previously). This exhibits itself as nasty oscillations around the peaks. We can tweak the data to make these go away by multiplying the FID with an exponential function (Figure 4.1). [Pg.34]

This observation is expected from theory, as the observed thickness distributions are exactly the functions by which one-dimensional short-range order is theoretically described in early literature models (Zernike and Prins [116] J. J. Hermans [128]). From the transformed experimental data we can determine, whether the principal thickness distributions are symmetrical or asymmetrical, whether they should be modeled by Gaussians, gamma distributions, truncated exponentials, or other analytical functions. Finally only a model that describes the arrangement of domains is missing - i.e., how the higher thickness distributions are computed from two principal thickness distributions (cf. Sect. 8.7). Experimental data are fitted by means of such models. Unsuitable models are sorted out by insufficient quality of the fit. Fit quality is assessed by means of the tools of nonlinear regression (Chap. 11). [Pg.167]

Several computed IDFs of iterated stochastic structures are presented in Fig. 8.40. As long as the crystallite thickness is uniform, the truncated exponentials of the amorphous thickness distributions are clearly identified in the IDF. [Pg.189]

Dodelet and Freeman, 1975 Jay-Gerin et ah, 1993). The main outcome from such analysis is that the free-ion yield, and therefore by implication the (r(h) value, increases with electron mobility, which in turn increases with the sphericity of the molecule. The heuristic conclusion is that the probability of inter-molecular energy losses decreases with the sphericity of the molecule, since there is no discernible difference between the various hydrocarbons for electronic or intramolecular vibrational energy losses. The (rth) values depend somewhat on the assumed form of distribution and, of course, on the liquid itself. At room temperature, these values range from -25 A for a truncated power-law distribution in n-hexane to -250 A for an exponential distribution in neopentane. [Pg.268]

Expansion of Pesc in powers of E is generally not recommended, because that expansion truncated to a finite number of terms results in large error as in a similar expansion of an exponential function of large argument. [Pg.307]

Edwards et al. (6) made the assumption that was equal to 4>pure a at the same pressure and temperature. Further theyused the virial equation, truncated after the second term to estimate pUre a These assumptions are satisfactory when the total pressure is low or when the mole fraction of the solute in the vapor phase is near unity. For the water, the assumption was made that <(>w, , aw and the exponential term were unity. These assumptions are valid when the solution consists mostly of water and the total pressure is low. The activity coefficient of the electrolyte was calculated using the extended Debye-Hiickel theory ... [Pg.52]

A source of error in the CASSCF(6e, 6o)-based methods is an incomplete treatment of the active-core relaxation. Although some effects of active-core relaxation are incorporated via the exponential operator in the CT calculations, this is incomplete due to the truncation of some operators in the ccaa class as explained in Section lll.C. Comparing CAS(10e, 80) with CAS(6e, 60) shows us the effects of the truncation. At the equilibrium structure (rNN = 1.15 A), we observe that the L-CTSD energy with CAS(6e, 60) is 3.5 mEh higher than that with CAS(10e, 80). For comparison, the MRMP energy with CAS(6e, 60) is 6.7 mEh higher that that with CAS(10e, 80). Thus the truncated ccaa operators... [Pg.374]

For thin systems with low absorbance, the exponential can be expanded and truncated at two terms so that the absorbed light intensity becomes [92]... [Pg.186]

When simple electrical RC filters are treated, the truncated exponential e, x,H(x) is indispensable. Its transform is given by (2n) 1/2(1 — jco)/( 1 + co2). If the truncated exponential is reflected about the origin, eliminating H(x) and leaving e x, the imaginary part of the transform disappears. We obtain the transform (2/7c)1/2/(l + co2). This is the resonance contour, Cauchy distribution, or Lorentzian shape encountered previously in Section III.B. [Pg.17]

In Eq. (12.16), one may imagine taking X intervals so small that AE on any given interval is arbitrarily close to zero. In that case, we may represent the exponential as a truncated power series, deriving... [Pg.435]

As a check on the consistency of our mathematics, it is profitable to verify that Equation (63) reduces to Equation (37) in the limit of low potentials. Expanding the exponentials in T and truncating the series so that only one term survives in both the numerator and denominator results in the Debye-Hiickel expression, Equation (37). [Pg.518]

Delta function Exponential Power law Gaussian Truncated gaussian... [Pg.179]


See other pages where Exponential truncated is mentioned: [Pg.428]    [Pg.428]    [Pg.110]    [Pg.55]    [Pg.22]    [Pg.187]    [Pg.188]    [Pg.308]    [Pg.308]    [Pg.3]    [Pg.312]    [Pg.339]    [Pg.363]    [Pg.268]    [Pg.2]    [Pg.76]    [Pg.30]    [Pg.372]    [Pg.397]    [Pg.25]    [Pg.17]    [Pg.142]    [Pg.142]    [Pg.225]    [Pg.526]    [Pg.173]    [Pg.179]    [Pg.179]   
See also in sourсe #XX -- [ Pg.17 ]

See also in sourсe #XX -- [ Pg.199 ]




SEARCH



Truncating

Truncation

Truncation of the Exponential Ansatz

© 2024 chempedia.info