There are however some stringent restrictions on the applicability of the adiabatic principle (Mehra and Rechenberg [1982]). Ehrenfest himself [1917] showed that it was applicable to simply periodic systems. These are systems having two or more frequencies which are rational fractions of each other. In such systems the motion will necessarily repeat itself after a fixed interval of time. Burgers [1917], a student of Ehrenfest, showed that it was also applicable... [Pg.20]

In the first place, the difference between the (NA) systems and the (A) ones is that for the first there exists always a periodic solution with period 2w (or a rational fraction of 2ir), whereas for the second, the period of oscillation (if it exists) is determined by the parameters... [Pg.350]

In Europe the notion of the zero evolved slowly in various forms. Eventually, probably to express debts, it was found necessary to invent negative integers. The requirements of trade and commerce lead to the use of fractions, as ratios of whole numbers. However, it is obviously more convenient to express fractions in the form of decimals. The ensemble of whole numbers and fractions (as ratios of whole numbers) is referred to as rational numbers. The mathematical relation between decimal and rational fractions is of importance, particularly in modem computer applications. [Pg.216]

As an example, consider the decimal fraction x — 0.616161 . Multiplication by 100 yields the expression 100 x = 61.6161 = 61 + jc and thus, x = 61/99, is a rational fraction. In general, if a decimal expression contains an infinitely repeating set of digits (61 in this example), it is a rational number. However, most decimal fractions do not contain a repeating set of... [Pg.216]

The expression given for X as a function of C leaves us in trouble at both ends of the diffusion profile. X appropriately tends towards + oo and - oo when CCe tends asymptotically towards —0.05 and 1.93, respectively, which are nearly the extreme concentrations in the profile. This is what we expect from an infinite system. However, the integrals of the rational fractions are simply natural logarithms which cannot be evaluated for a zero argument and therefore do not converge when evaluated between C0 and Cl. We will therefore restrict the calculation to the interval between extreme concentrations, say C0 = 1.865 and = 0.012. The flux at both ends will not be strictly zero, since for these values,... [Pg.427]

More precisely, the following proposition is valid (see Theorem 14.1 in a monograph by Bykov et al., 1998). We are assuming that none of rational fractions Bq,...,Bl in Equation (25) is reducible. We write Bo B if Bq/B/O for generic... [Pg.63]

In Figure 2.7 the arrows indicate possible orientations of the total angular momentum vector such that the component in the line-of-force direction is always a rational fraction of the total measure. The possible vectors are identified by their projection on the radius of the unit circle as fractions k/n. The quantum number k = 0 is considered meaningless. In Sommerfeld s words [8] ... [Pg.29]

The most convincing derivation of periodic structure, using the concepts of number theory, comes from a comparison with Farey sequences. The Farey scheme is a device to arrange rational fractions in enumerable order. Starting from the end members of the interval [0,1] an infinite tree structure is generated by separate addition of numerators and denominators to produce the Farey sequences ni of order n, where n limits the values of denominators... [Pg.141]

Each rational fraction, h/k, defines a Ford circle with a radius and y-coordinate of 1/(2k2), positioned at an -coordinate h/k. The Ford circles of any unimodular pair are tangent to each other and to the x-axis. The circles, numbered from 1 to 4 in the construction overleaf, represent the Farey sequence of order 4. This sequence has the remarkable property of one-to-one correspondence with the natural numbers ordered in sets of 2k2 and in the same geometrical relationship as the Ford circles of 4. [Pg.141]

The rational fractions defined by successive Fibonacci numbers in the sequence ... [Pg.143]

The principle that governs the periodic properties of atomic matter is the composition of atoms, made up of integral numbers of discrete sub-atomic units - protons, neutrons and electrons. Each nuclide is an atom with a unique ratio of protonsmeutrons, which defines a rational fraction. The numerical function that arranges rational fractions in enumerable order is known as a Farey sequence. A simple unimodular Farey sequence is obtained by arranging the fractions (n/n+1) as a function of n. The set of /c-modular sequences ... [Pg.282]

As an example, Table 5 shows that the terms up to Cio, together with a second-order perturbation correction [38], account for the variationally calculated energy of the IslOA state to within an accuracy of only a few Hz. All the entries can be expressed analytically as rational fractions. For example, the Ci r A) contribution is exactly (in atomic units)... [Pg.68]

Here p is either integer (p = 1,2,3, etc.) for the integer quantum Hall effect, first measured by von Klitzing25 at cryogenic temperatures [14], or a rational fraction (p 1 /3, 1/5, 5/2, etc.) for the fractional quantum Hall effect, first measured by Tsui, Stormer, and Laughlin [15]. The very well measured quantity ez/h = 25.81280745 kQ is called the von Klitzing constant, although it should also be called Landauer s constant. [Pg.453]

For p values with rational fractions (p 1/2,2/3), a Wigner crystal [56] can occur The charges alternate regularly in the crystal, yielding a "frozen CDW", so that one site has p 0, the next p 1, and so on. A Wigner crystal is thus the antithesis of a mixed-valent [38] state. [Pg.478]

Figure 2.9 Farey sequence of rational fractions. Starting with the first row and reading from right to left 3/1 is identified as the 12th rational fraction. |

Figure 2.10 Possible combinations of integers Z and A — Z such that A = 4m and Z = 2n, represented as rational fractions plotted against Z... |

One application of an analog oscilloscope is in examining the relative phase relationship of two sinusoidal wave forms, one of which (of frequency is supplied to the vertical input (/) of the oscilloscope, the other (of frequency /j/) to the horizontal input (x). When the display mode is chosen to be. v vs. /, the. v voltage replaces the internal sawtooth sweep voltage and the oscilloscope becomes a sensitive device for comparing the frequencies of the sine waves. When the ratio of the frequencies is a rational fraction, a symmetrical closed pattern called a Lissajous figure will appear on the screen. The frequency ratio can be obtained from the form of the pattern by using the formula... [Pg.608]

Below Tp, the static ( locked ) CDW of the conduction electrons at 2 kp (or 4 kp), couple with the other atomic or molecular electrons in the lattice, cause a slight lattice distortion, and gives rise to extra X-ray reflections. Above Tp, these CDW are mobile, with no phase locking between excitations on nearby chains one sees X-ray diffuse reflections, similar to thermal diffuse scattering, which sharpen as T is lowered. Below Tp the static distortion produces new, usually weak, reflections between reciprocal-lattice layer lines. When the band filling is a rational fraction (1/4, 1/2, 2/3,1, etc.) then these reflections overlap with certain Bragg reflections of the background lattice, and are more difficult to detect. [Pg.321]

When we deal with n terms of the same type, their sum can be represented by means of a rational fraction... [Pg.408]

The evaluation of the inverse of this equation requires us to decompose it into rational fractions, as follows ... [Pg.738]

See also in sourсe #XX -- [ Pg.209 ]

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