Track radius

Turning now to alpha radiation, the track density is such that almost any overlap with a macromolecule results in multiple hits. For 2-m.e.v. alpha particles, a dose of r rads requires a flux of only 4 X 104 r particles per sq. cm., and with a track radius a = 15A., the total area covered is only 2.8 X 10"9 r per sq. cm. For 50% of target molecules to be hit at the doses envisaged each must have a larger area. 

The ion track radius is also an important parameter in such reactions, reflecting the local spatial distribution of energy deposited by an incident ion and influencing the character of subsequent chemical reactions [8-12]. We recently reported on main-chain scission and crosslinking reactions in a variety of polymer systems and proposed chemical core sizes in ion tracks based on discussion of the non-homogeneous spatial distribution of reactions [9-15]. Intratrack crosslinking reactions are also of interest with respect to the potential for the direct formation of nano-structured materials, and materials exhibiting these reactions have been successfully visualized in recent years [11,13]. However, despite the extensive experimental and theoretical study undertaken to date, many factors in the relationship between the ion track structure and the chemical core radius remain unclear. This paper proposes a new formulation that determines the chemical core radius in an ion track based on the initial... 

Track radius, corresponding to chemical core in the previous section, is discussed from fluence-dependence of radical saturation [95], convergence of molecular weight distribution [88], and decay of optical density [96], under the assumption that inter-track overlapping would affect these phenomena. The track radius thus evaluated ranges from a few to several dozen nanometers, and increase with increasing LET. 

Figure 5. Schematic of pin-on-disk wear test system. F is the normal force on the pin, d is the pin diameter, D Is the disk diameter, R Is the wear track radius, and W is the...

F. 3 Speed dependence of coefficient of friction (p) ftom mini-traction-machine measmements for different compositions of HEPES-glycerol mixtures with ( ) and without ( ) polymer. A rotating steel ball is brought into contact with a rotating glass disk under an applied load of 10 N and with a track radius of 20.7 mm. The mean speed of the ball and disk varied from 0 to 2500 mm/s with a SRR of 10%... 

Fig. 6 Coefficient of friction (fi) versus number of laps for sliding contact between a steel pin and a glass disk in a pin-on-disk tribometer. a For HEPES solution as lubricant fluid b For 50 vol.% glycerol in HEPES as lubricant fluid. Case II concerns the tribopair pre-incubated in an aqueous-polymer-containing glycerol solution, while the solution in the cup does not contain any dissolved polymer. In Case ID, the surface was also pre-coated with polymer in a similar way, and also the solution in the cup contains the polymer at a concentration of 0.25 mg/ml. Case IV represents surfaces that are similarly pre-coated with polymer but the polymer concentration of the solution in the cup is changed from 0 to 0.25 mg/ml following the injection of the polymer solution into the cup at the 13th lap (load = 2 N, sliding speed = 5 mm/s and track radius = 3 mm)...

The core of the network is the region of the rail network in which the branch line of two transformer substations or of any other branch line is less than 2 km distant in a direct line. All branch lines outside the core of the network are termed outlying lines. In a branched rail network, not only the stretches of line within a circle with a radius of 2 km from the most negative return current point of a transformer substation belong to the core of the network, but also connecting branch lines that are less than 2 km from each other [1]. The area of a network core can be simply determined on a track plan with the help of a circular template as in Fig. 15-1. 

FIGURE 26.17 Temperature rise between a rubber track and a steel slider as function of speed (a) cone tip radius 1 mm, (b) sphere 11 mm dia. and (c) cone sliding on wet track. Load in all cases 2.5 N. (From Grosch, K.A., The Physics of Tire Traction, Theory and Experiment, Hayes, D.L. and Browne, A.L. (eds.). Plenum Press, New York/London, 1974.)... 

The main purpose of railroads is to provide an inexpensive means for obtaining raw materials and for shipping products. This means that they should be close to raw material and / or product storage. Buildings and loading docks should be set back 8 ft (2.4 m) from the center of the railroad track. Spurs and switches should be laid out with a 100 ft. (30 m) radius.3 Roads are used not only for these purposes, but... 

The Samuel-Magee model can be extended to a-particle tracks, considered as cylindrical columns formed by excessive spur overlap due to high LET. To a good approximation, the length I of the cylinder remains constant while its radius grows by diffusion. In this geometry, the normalized radical distribution is given by... 

The Hayashi track (Hayashi 1961, 1966) is the locus of fully convective stars in the HR diagram, dependent on the mass, luminosity and chemical composition. However, it is mainly the surface properties - luminosity and radius or luminosity and effective temperature - that govern the entire stellar structure by fixing the adiabatic constant. A sketch derivation of its properties is the following. 

Fig. 5.19. Evolutionary track in the HR diagram of an AGB model of total mass 0.6 Mq, initial composition (Y, Z) = (0.25, 0.001 Z /20). Heavy dots marked 2 to 11 indicate the start of a series of thermal pulses (see Fig. 5.20), which lead to excursions along the steep diagonal lines. Numbers along the horizontal and descending track indicate times in years relative to the moment when an ionized planetary nebula appears and (in parentheses) the mass of the envelope in units of Mq. R = 0.0285 indicates a line of constant radius (R in solar units) corresponding to the white-dwarf sequence. Shaded areas represent earlier evolutionary stages for stars with initial masses 3,5 and 7 Mq and the steep broken line marks the high-temperature boundary of the instability strip in which stars pulsate in their fundamental mode. The y-axis gives log L/Lq. Adapted from Iben and Renzini (1983).

For a microring resonator with a waveguide width of 5 pm and coupling gap of 200 nm, a resonance extinction ratio of 12 dB for TE polarization and 9 dB for TM polarization has been achieved, as shown in Fig. 2.10. The ring resonator had a race track shape with circular sections of 500 pm radius and straight coupling section of 100 pm in length. The width of the two exposed strips is about 50 pm. 

The BioCD laser scanning takes place on circular tracks of fixed radius r on the disc that is spinning with angular frequency co. The linear velocity is... 

The equation of motion of a charged particle in a magnetic field of strength B is given by the following, where r is the radius of the circular track taken by the ion ... 

The quantities determined directly by the spectroscopic analysis as performed for hot stars are effective temperature Tef f surface gravity g and element abundances. Of course, this is not sufficient to place a star in the HR diagram. This is possible only with further knowledge of either luminosity, radius, mass or distance of the star. However, uncertainties in these quantities (which are usually much larger than the uncertainties in Te and g) directly translate into the HR diagram. On the other hand, theoretical evolutionary tracks can be easily expressed in terms of Teff and g without loss of precision. It is therefore good practice to discuss the results of spectroscopic analyses directly in a (log Te -log g) diagram as we shall do in this paper. 

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